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Large area avalanche photodiode detector array upgrade for a ruby-laser Thomson scattering system
Large area avalanche photodiode detector array upgrade for a ruby-laser Thomson scattering system T microchannel plate MCP detector was replaced with an array of modular large area avalanche photodiode detectors-laser head, collection optics, a Jarrell-Ash MonoSpec-27 Model 82-499 spectrometer, and avalanche photodiode
Biewer, Theodore
A photon-counting photodiode array detector for far ultraviolet (FUV) astronomy
NASA Technical Reports Server (NTRS)
A compact, stable, single-stage intensified photodiode array detector designed for photon-counting, far ultraviolet astronomy applications employs a saturable, 'C'-type MCP (Galileo S. MCP 25-25) to produce high gain pulses with a narrowly peaked pulse height distribution. The P-20 output phosphor exhibits a very short decay time, due to the high current density of the electron pulses. This intensifier is being coupled to a self-scanning linear photodiode array which has a fiber optic input window which allows direct, rigid mechanical coupling with minimal light loss. The array was scanned at a 250 KHz pixel rate. The detector exhibits more than adequate signal-to-noise ratio for pulse counting and event location.
Hartig, G. F.; Moos, H. W.; Pembroke, R.; Bowers, C.
General method for determining flavonoids in medicinal plants and raw cosmetics using HPLC with a photodiode array detector
The separation of flavonoids in medicinal plants and raw cosmetics was described by high performance liquid chromatography\\u000a with a photodiode array detector. The influence of wavelength, mobile phase component, sample treatment including solvent\\u000a selection and extraction and other conditions affecting the separation were optimized. Elution with methanol\\/phosphoric acid\\u000a (pH 2.0) in a Phenomenex C18 (25 cm ? 4.6 mm i.d.)
L.-H. Wang; W.-H. Li
Radiation Effects on the Performance of CMOS Photodiode Array Detectors and the Role of Gain-Offset Corrections
We report the observation of performance degradation in a detector consisting of a phosphor screen and a CMOS (complementary metal-oxide-semiconductor) photodiode array under the continuous irradiation of 45-kVp x-rays. The performance was assessed in terms of dark pixel signal, dynamic range, modulation-transfer function (MTF), noise-power spectrum (NPS), and detective quantum efficiency (DQE). From the measurement results, it has been observed
Ho Kyung Kim; Min Kook Cho; Thorsten Achterkirchen; Wonho Lee
Lutetium oxyorthosilicate block detector readout by avalanche photodiode arrays for high resolution animal PET
Avalanche photodiodes (APDs) have proven to be useful as light detectors for high resolution positron emission tomography (PET). Their compactness makes these devices excellent candidates for replacing bulky photomultiplier tubes (PMTs) in PET systems where space limitations are an issue. The readout of densely packed, 10 10 lutetium oxyorthosilicate (LSO) block detectors (crystal size 2.0 2.0 12 mm3) with custom-built
B J Pichler; B K Swann; J Rochelle; R E Nutt; S R Cherry; S B Siegel
Simultaneous determination of catechins, caffeine and gallic acids in green, Oolong, black and pu-erh teas using HPLC with a photodiode array detector
A simple and fast HPLC method using a photodiode array detector was developed for simultaneous determination of four major catechins, gallic acid and caffeine. After multiple extractions with aqueous methanol and acidic methanol solutions, tea extract was separated within 20 min using a methanol�acetate�water buffer gradient elution system on a C18 column. The sample extraction data demonstrated that the single
Yuegang Zuo; Hao Chen; Yiwei Deng
Avalanche Photodiode Arrays for Optical Communications Receivers
NASA Technical Reports Server (NTRS)
An avalanche photodiode (APD) array for ground-based optical communications receivers is investigated for the reception of optical signals through the turbulent atmosphere. Kolmogorov phase screen simulations are used to generate realistic spatial distributions of the received optical field. It is shown that use of an APD array for pulse-position modulation detection can improve performance by up to 4 dB over single APD detection in the presence of turbulence, but that photon-counting detector arrays yield even greater gains.
Srinivasan, M.; Vilnrotter, V.
Instrumentation: Photodiode Array Detectors in UV-VIS Spectroscopy. Part II.
ERIC Educational Resources Information Center
A previous part (Analytical Chemistry; v57 n9 p1057A) discussed the theoretical aspects of diode ultraviolet-visual (UV-VIS) spectroscopy. This part describes the applications of diode arrays in analytical chemistry, also considering spectroelectrochemistry, high performance liquid chromatography (HPLC), HPLC data processing, stopped flow, and�
Jones, Dianna G.
Nuclear resonant scattering measurements on (57)Fe by multichannel scaling with a 64-pixel silicon avalanche photodiode linear-array detector.
We developed a silicon avalanche photodiode (Si-APD) linear-array detector for use in nuclear resonant scattering experiments using synchrotron X-rays. The Si-APD linear array consists of 64 pixels (pixel size: 100 � 200 ?m(2)) with a pixel pitch of 150 ?m and depletion depth of 10 ?m. An ultrafast frontend circuit allows the X-ray detector to obtain a high output rate of >10(7) cps per pixel. High-performance integrated circuits achieve multichannel scaling over 1024 continuous time bins with a 1 ns resolution for each pixel without dead time. The multichannel scaling method enabled us to record a time spectrum of the 14.4 keV nuclear radiation at each pixel with a time resolution of 1.4 ns (FWHM). This method was successfully applied to nuclear forward scattering and nuclear small-angle scattering on (57)Fe. PMID:25430093
Kishimoto, S; Mitsui, T; Haruki, R; Yoda, Y; Taniguchi, T; Shimazaki, S; Ikeno, M; Saito, M; Tanaka, M
Nuclear resonant scattering measurements on 57Fe by multichannel scaling with a 64-pixel silicon avalanche photodiode linear-array detector
NASA Astrophysics Data System (ADS)
We developed a silicon avalanche photodiode (Si-APD) linear-array detector for use in nuclear resonant scattering experiments using synchrotron X-rays. The Si-APD linear array consists of 64 pixels (pixel size: 100 � 200 ?m2) with a pixel pitch of 150 ?m and depletion depth of 10 ?m. An ultrafast frontend circuit allows the X-ray detector to obtain a high output rate of >107 cps per pixel. High-performance integrated circuits achieve multichannel scaling over 1024 continuous time bins with a 1 ns resolution for each pixel without dead time. The multichannel scaling method enabled us to record a time spectrum of the 14.4 keV nuclear radiation at each pixel with a time resolution of 1.4 ns (FWHM). This method was successfully applied to nuclear forward scattering and nuclear small-angle scattering on 57Fe.
Kishimoto, S.; Mitsui, T.; Haruki, R.; Yoda, Y.; Taniguchi, T.; Shimazaki, S.; Ikeno, M.; Saito, M.; Tanaka, M.
Simultaneous determination of eperisone hydrochloride and paracetamol in mouse plasma by high performance liquid chromatography-photodiode array detector.
This paper reports the validation of a quantitative high performance liquid chromatography-photodiode array (HPLC-PDA) method for the simultaneous analysis, in mouse plasma, of eperisone hydrochloride and paracetamol by protein precipitation using zinc sulphate-methanol-acetonitrile. The analytes were resolved on a Gemini C18 column (4.6mm�250mm; 5?m particle size) using a gradient elution mode with a run time of 15min, comprising re-equilibration, at 60�C (�1�C). The method was validated over the concentration range from 0.5 to 25?g/mL for eperisone hydrochloride and paracetamol, in mouse plasma. Ciprofloxacin was used as Internal Standard. Results from assay validations show that the method is selective, sensitive and robust. The limit of quantification of the method was 0.5?g/mL for eperisone hydrochloride and paracetamol, and matrix-matched standard curves showed a good linearity, up to 25?g/mL with correlation coefficients (r(2))?0.9891. In the entire analytical range the intra and inter-day precision (RSD%) values were ?1.15% and ?1.46% for eperisone hydrochloride, and ?0.35% and ?1.65% for paracetamol. For both analytes the intra and inter-day trueness (bias%) values ranged, respectively, from -5.33% to 4.00% and from -11.4% to -4.00%. The method was successfully tested in pharmacokinetic studies after oral administration in mouse. Furthermore, the application of this method results in a significant reduction in terms of animal number, dosage, and improvement in speed, rate of analysis, and quality of pharmacokinetic parameters related to serial blood sampling. PMID:25704771
Locatelli, Marcello; Cifelli, Roberta; Di Legge, Cristina; Barbacane, Renato Carmine; Costa, Nicola; Fresta, Massimo; Celia, Christian; Capolupo, Carlo; Di Marzio, Luisa
Photodiode array to charged aerosol detector response ratio enables comprehensive quantitative monitoring of basic drugs in blood by ultra-high performance liquid chromatography.
Quantitative screening for a broad range of drugs in blood is regularly required to assess drug abuse and poisoning within analytical toxicology. Mass spectrometry-based procedures suffer from the large amount of work required to maintain quantitative calibration in extensive multi-compound methods. In this study, a quantitative drug screening method for blood samples was developed based on ultra-high performance liquid chromatography with two consecutive detectors: a photodiode array detector and a corona charged aerosol detector (UHPLC-DAD-CAD). The 2.1mm�150mm UHPLC column contained a high-strength silica C18 bonded phase material with a particle size of 1.8?m, and the mobile phase consisted of methanol/0.1% trifluoroacetic acid in gradient mode. Identification was based on retention time, UV spectrum and the response ratio from the two detectors. Using historic calibration over a one-month period, the median precision (RSD) of retention times was 0.04% and the median accuracy (bias) of quantification 6.75%. The median precision of the detector response ratio over two orders of magnitude was 12%. The applicable linear ranges were generally 0.05-5mgL(-1). The method was validated for 161 compounds, including antipsychotics, antidepressants, antihistamines, opioid analgesics, and adrenergic beta blocking drugs, among others. The main novelty of the method was the proven utility of the response ratio of DAD to CAD, which provided the additional identification efficiency required. Unlike with mass spectrometry, the high stability of identification and quantification allowed the use of facile historic calibration. PMID:25732578
Viinam�ki, Jenni; Ojanper�, Ilkka
Current isolating epitaxial buffer layers for high voltage photodiode array
An array of photodiodes in series on a common semi-insulating substrate has a non-conductive buffer layer between the photodiodes and the semi-insulating substrate. The buffer layer reduces current injection leakage between the photodiodes of the array and allows optical energy to be converted to high voltage electrical energy.
Morse, Jeffrey D. (Martinez, CA); Cooper, Gregory A. (Pleasant Hill, CA)
Design of Low Power CMOS Read-Out with TDI Function for Infrared Linear Photodiode Array Detectors
NASA Technical Reports Server (NTRS)
A new low voltage CMOS infrared readout circuit using the buffer-direct injection method is presented. It uses a single supply voltage of 1.8 volts and a bias current of 1uA. The time-delay integration technique is used to increase the signal to noise ratio. A current memory circuit with faulty diode detection is used to remove dark current for background compensation and to disable a photodiode in a cell if detected as faulty. Simulations are shown that verify the circuit that is currently in fabrication in 0.5ym CMOS technology.
Vizcaino, Paul; Ramirez-Angulo, Jaime; Patel, Umesh D.
Identification of components in Zhi-Zi-Da-Huang decoction by HPLC coupled with electrospray ionization tandem mass spectrometry, photodiode array and fluorescence detectors.
High-performance liquid chromatography (HPLC) coupled with electrospray ionization (ESI) tandem mass spectrometry (MS) in positive and negative ion mode and photodiode array (PDA) and fluorescence detectors (FD) was applied to simultaneously characterise thirty active components in Zhi-Zi-Da-Huang decoction (ZZDHD). The analysis was preformed on a Lichrospher C(18) column (4.6 mm x 250 mm, 5 microm) using a binary eluent (0.1% aqueous acetic acid (A) and methanol (B), 1 ml/min) under gradient conditions. Based on the retention times (t(R)), UV spectral data, fluorescence characteristics, results of extracted ion current (EIC), information of molecular weight and mass fragmentation behaviours, 17 flavonoids, five anthraquinones, two coumarins and six iridoids were detected and identified. The ESI-MS/MS fragmentation behaviour of iridoids, flavonoids, anthraquinones, coumarins was also proposed. The fragmentation patterns proposed could be extended to the components mentioned above but in different herbs and prescriptions. The method was useful for the identification of unknown components in the herbal system and other complex samples, especially for which standards are unavailable. PMID:19356878
Wang, Hang; Feng, Fang
ASIC Readout Circuit Architecture for Large Geiger Photodiode Arrays
NASA Technical Reports Server (NTRS)
The objective of this work was to develop a new class of readout integrated circuit (ROIC) arrays to be operated with Geiger avalanche photodiode (GPD) arrays, by integrating multiple functions at the pixel level (smart-pixel or active pixel technology) in 250-nm CMOS (complementary metal oxide semiconductor) processes. In order to pack a maximum of functions within a minimum pixel size, the ROIC array is a full, custom application-specific integrated circuit (ASIC) design using a mixed-signal CMOS process with compact primitive layout cells. The ROIC array was processed to allow assembly in bump-bonding technology with photon-counting infrared detector arrays into 3-D imaging cameras (LADAR). The ROIC architecture was designed to work with either common- anode Si GPD arrays or common-cathode InGaAs GPD arrays. The current ROIC pixel design is hardwired prior to processing one of the two GPD array configurations, and it has the provision to allow soft reconfiguration to either array (to be implemented into the next ROIC array generation). The ROIC pixel architecture implements the Geiger avalanche quenching, bias, reset, and time to digital conversion (TDC) functions in full-digital design, and uses time domain over-sampling (vernier) to allow high temporal resolution at low clock rates, increased data yield, and improved utilization of the laser beam.
Vasile, Stefan; Lipson, Jerold
Design studies for a PET detector module using a PIN photodiode to measure depth of interaction
We present design studies of a multi-layer PET detector module that uses an 8�8 array of 3 mm square PIN photodiodes to both identify the crystal of interaction and measure the depth of interaction. Each photodiode is coupled to one end of a 3�3�30 mm BGO crystal, with the opposite ends of 64 such crystals attached to a single 1\\
W. W. Moses; S. E. Derenzo
A polychromator-type near-infrared spectrometer with a high-sensitivity and high-resolution photodiode array detector for pharmaceutical process monitoring on the millisecond time scale.
In the fine chemicals industry, particularly in the pharmaceutical industry, advanced sensing technologies have recently begun being incorporated into the process line in order to improve safety and quality in accordance with process analytical technology. For estimating the quality of powders without preparation during drug formulation, near-infrared (NIR) spectroscopy has been considered the most promising sensing approach. In this study, we have developed a compact polychromator-type NIR spectrometer equipped with a photodiode (PD) array detector. This detector is consisting of 640 InGaAs-PD elements with 20-?m pitch. Some high-specification spectrometers, which use InGaAs-PD with 512 elements, have a wavelength resolution of about 1.56 nm when covering 900-1700 nm range. On the other hand, the newly developed detector, having the PD with one of the world's highest density, enables wavelength resolution of below 1.25 nm. Moreover, thanks to the combination with a highly integrated charge amplifier array circuit, measurement speed of the detector is higher by two orders than that of existing PD array detectors. The developed spectrometer is small (120 mm � 220 mm � 200 mm) and light (6 kg), and it contains various key devices including the high-density and high-sensitivity PD array detector, NIR technology, and spectroscopy technology for a spectroscopic analyzer that has the required detection mechanism and high sensitivity for powder measurement, as well as a high-speed measuring function for blenders. Moreover, we have evaluated the characteristics of the developed NIR spectrometer, and the measurement of powder samples confirmed that it has high functionality. PMID:23464192
Murayama, Kodai; Genkawa, Takuma; Ishikawa, Daitaro; Komiyama, Makoto; Ozaki, Yukihiro
A polychromator-type near-infrared spectrometer with a high-sensitivity and high-resolution photodiode array detector for pharmaceutical process monitoring on the millisecond time scale
NASA Astrophysics Data System (ADS)
In the fine chemicals industry, particularly in the pharmaceutical industry, advanced sensing technologies have recently begun being incorporated into the process line in order to improve safety and quality in accordance with process analytical technology. For estimating the quality of powders without preparation during drug formulation, near-infrared (NIR) spectroscopy has been considered the most promising sensing approach. In this study, we have developed a compact polychromator-type NIR spectrometer equipped with a photodiode (PD) array detector. This detector is consisting of 640 InGaAs-PD elements with 20-?m pitch. Some high-specification spectrometers, which use InGaAs-PD with 512 elements, have a wavelength resolution of about 1.56 nm when covering 900-1700 nm range. On the other hand, the newly developed detector, having the PD with one of the world's highest density, enables wavelength resolution of below 1.25 nm. Moreover, thanks to the combination with a highly integrated charge amplifier array circuit, measurement speed of the detector is higher by two orders than that of existing PD array detectors. The developed spectrometer is small (120 mm � 220 mm � 200 mm) and light (6 kg), and it contains various key devices including the high-density and high-sensitivity PD array detector, NIR technology, and spectroscopy technology for a spectroscopic analyzer that has the required detection mechanism and high sensitivity for powder measurement, as well as a high-speed measuring function for blenders. Moreover, we have evaluated the characteristics of the developed NIR spectrometer, and the measurement of powder samples confirmed that it has high functionality.
Murayama, Kodai; Genkawa, Takuma; Ishikawa, Daitaro; Komiyama, Makoto; Ozaki, Yukihiro
Modeling scintillator-photodiodes as detectors for megavoltage CT.
The use of cadmium tungstate (CdWO4) and cesium iodide [CsI(Tl)] scintillation detectors is studied in megavoltage computed tomography (MVCT). A model describing the signal acquired from a scintillation detector has been developed which contains two steps: (1) the calculation of the energy deposited in the crystal due to MeV photons using the EGSnrc Monte Carlo code; and (2) the transport of the optical photons generated in the crystal voxels to photodiodes using the optical Monte Carlo code DETECT2000. The measured detector signals in single CdWO4 and CsI(Tl) scintillation crystals of base 0.275 x 0.8 cm2 and heights 0.4, 1, 1.2, 1.6 and 2 cm were, generally, in good agreement with the signals calculated with the model. A prototype detector array which contains 8 CdWO4 crystals, each 0.275 x 0.8 x 1 cm3, in contact with a 16-element array of photodiodes was built. The measured attenuation of a Cobalt-60 beam as a function of solid water thickness behaves linearly. The frequency dependent modulation transfer function [MTF(f)], noise power spectrum [NPS(f)], and detective quantum efficiency [DQE(f)] were measured for 1.25 MeV photons (in a Cobalt-60 beam). For 6 MV photons, only the MTF(f) was measured from a linear accelerator, where large pulse-to-pulse fluctuations in the output of the linear accelerator did not allow the measurement of the NPS(f). A two-step Monte Carlo simulation was used to model the detector's MTF(f), NPS(f) and DQE(f). The DQE(0) of the detector array was found to be 26% and 19% for 1.25 MeV and 6 MV photons, respectively. For 1.25 MeV photons, the maximum discrepancies between the measured and modeled MTF(f), relative NPS(f) and the DQE(f) were found to be 1.5%, 1.2%, and 1.9%, respectively. For the 6 MV beam, the maximum discrepancy between the modeled and the measured MTF(f) was found to be 2.5%. The modeling is sufficiently accurate for designing appropriate detectors for MVCT. PMID:15191313
Monajemi, T T; Steciw, S; Fallone, B G; Rathee, S
Scintillator-photodiode linear arrays for X-ray inspection system
The evaluations of the following performances of detectors for design of the radiographic system were carried out by mathematical simulation method and experimentally: sensitivity to absorbed energy, noise level, form of apparatus function for spatial resolution of detectors array. The results of calculations were used for designing of CdWO{sub 4}-Si arrays with optimal sizes of scintillator and photodiode for resolution ability. At the given stage the quality of radiation detectors was evaluated by spectroscopic methods. At the bias voltage on photodiode 24 V, the sensitivity of detectors has made up (0.95--1.00) {times} 10{sup {minus}21} C/eV, noise level -- (1.50--1.75) {times} 10{sup {minus}16} C together with electronic noise. Dynamic range at absorbed energy by separate detector is more than 10{sup 5}, what is sufficient to get required image contrast.
Ignatov, S.M.; Potapov, V.N.; Fedin, A.V.; Chirkin, V.M.; Urutskoev, L.I. [RECOM Ltd., Moscow (Russian Federation). Kurchatov Inst.; Gostilo, V.V.; Kondrashov, V.V.; Sokolov, A.D. [Baltic Scientific Instruments, Riga (Latvia)
NSDL National Science Digital Library
This Quicktime presentation explains the basics of the photodiode. Some concepts that are explained include the photodiode package, photodiode illumination, internal connections, photodiode chip, photon absorption and electron-hole pair generation.
Van Zeghbroeck, Bart Jozef
Characterization of InGaAs avalanche photodiode arrays with varying geometries for free-space optical communication
NASA Astrophysics Data System (ADS)
Photodiode arrays are instrumental in providing pointing and tracking information for free space optical communication systems. Recent advances in the fabrication and development of low noise, high bandwidth avalanche photodiode (APD) arrays have enabled these devices to be used not only as position sensitive detectors (PSD) for tracking but also as communications receivers. In a collaborative effort with Optogration, Inc., the U.S. Naval Research Laboratory has developed avalanche photodiode arrays with three different geometries: a 3x3 square pixel array, a centered hexagonal pixel array, and a 5 pixel concentric array configuration with a center pixel and four periphery pixels. The characterization and performance of each array geometry will be described along with associated front-end and digital electronics. Design tradeoffs for maximizing the performance of a given array geometry will also be discussed.
Ferraro, Mike S.; Burris, Harris R.; Mahon, Rita; Rabinovich, William S.; Freeman, Wade T.; Murphy, James L.; Goetz, Peter G.; Moore, Christopher I.; Thomas, Linda M.; Clark, William R.; Waters, William D.; Vaccaro, Kenneth; Krejca, Brian D.
Photodiode arrays having minimized cross-talk between diodes
Photodiode arrays are formed with close diode-to-diode spacing and minimized cross-talk between diodes in the array by isolating the diodes from one another with trenches that are formed between the photodiodes in the array. The photodiodes are formed of spaced regions in a base layer, each spaced region having an impurity type opposite to that of the base layer to define a p-n junction between the spaced regions and the base layer. The base layer meets a substrate at a boundary, with the substrate being much more heavily doped than the base layer with the same impurity type. The trenches extend through the base layer and preferably into the substrate. Minority carriers generated by absorption of light photons in the base layer can only migrate to an adjacent photodiode through the substrate. The lifetime and the corresponding diffusion length of the minority carriers in the substrate is very short so that all minority carriers recombine in the substrate before reaching an adjacent photodiode.
Guckel, Henry (Madison, WI); McNamara, Shamus P. (Madison, WI)
Avalanche photodiode based detector for beam emission spectroscopy.
An avalanche photodiode based (APD) detector for the visible wavelength range was developed for low light level, high frequency beam emission spectroscopy (BES) experiments in fusion plasmas. This solid state detector has higher quantum efficiency than photomultiplier tubes, and unlike normal photodiodes, it has internal gain. This paper describes the developed detector as well as the noise model of the electronic circuit. By understanding the noise sources and the amplification process, the optimal amplifier and APD reverse voltage setting can be determined, where the signal-to-noise ratio is the highest for a given photon flux. The calculations are compared to the absolute calibration results of the implemented circuit. It was found that for a certain photon flux range, relevant for BES measurements (?10(8)-10(10)?photons/s), the new detector is superior to both photomultipliers and photodiodes, although it does not require cryogenic cooling of any component. The position of this photon flux window sensitively depends on the parameters of the actual experimental implementation (desired bandwidth, detector size, etc.) Several detector units based on these developments have been built and installed in various tokamaks. Some illustrative results are presented from the 8-channel trial BES system installed at Mega-Ampere Spherical Tokamak (MAST) and the 16-channel BES system installed at the Torus Experiment for Technology Oriented Research (TEXTOR). PMID:21034087
Dunai, D; Zoletnik, S; S�rk�zi, J; Field, A R
Large-Format AlGaN PIN Photodiode Arrays for UV Images
NASA Technical Reports Server (NTRS)
A large-format hybridized AlGaN photodiode array with an adjustable bandwidth features stray-light control, ultralow dark-current noise to reduce cooling requirements, and much higher radiation tolerance than previous technologies. This technology reduces the size, mass, power, and cost of future ultraviolet (UV) detection instruments by using lightweight, low-voltage AlGaN detectors in a hybrid detector/multiplexer configuration. The solar-blind feature eliminates the need for additional visible light rejection and reduces the sensitivity of the system to stray light that can contaminate observations.
Aslam, Shahid; Franz, David
Infrared imaging arrays based on superlattice photodiodes
We report on the status of focal plane arrays (FPAs) based on GaSb\\/InAs type-II superlattice diodes grown by molecular beam epitaxy (MBE) and designed for infrared absorption in the 2-5mum and 8-10mum bands. Recent LWIR devices have produced differential resistance-area product greater than 100 Ohmcm2 at 80K with a long wavelength cutoff of approximately 10mum. The measured quantum efficiency of
Cory J. Hill; Alexander Soibel; Sam A. Keo; Jason M. Mumolo; Sarath D. Gunapala; David R. Rhiger; Robert E. Kvaas; Sean F. Harris
Detector arrays in spectroscopy
NASA Astrophysics Data System (ADS)
Spatially dispersed spectra of ions, electrons or photons are traditionally measured by scanning the spectra across a narrow slit behind which is a detector. However, the efficiency increase offered by arrays of detectors is so large that their development is increasingly demanding the attention of spectrometer manufacturers. One-dimensional arrays of independent detectors (discrete electrode arrays) offer the highest data accumulation rate as detection can occur simultaneously at many sites, but a high resolution array of this type requires much associated electronics and this has limited the size and the market of such devices. The design and performance issues relating to discrete electrode arrays are discussed and a new high resolution array with all electronics integrated on a single silicon chip developed at Aberystwyth is described. A familiarity with silicon technology is not required by the reader. It is shown that integration brings not only advantages of scale but also of performance.
Birkinshaw, K.
Organic light detectors: photodiodes and phototransistors.
While organic electronics is mostly dominated by light-emitting diodes, photovoltaic cells and transistors, optoelectronics properties peculiar to organic semiconductors make them interesting candidates for the development of innovative and disruptive applications also in the field of light signal detection. In fact, organic-based photoactive media combine effective light absorption in the region of the spectrum from ultraviolet to near-infrared with good photogeneration yield and low-temperature processability over large areas and on virtually every substrate, which might enable innovative optoelectronic systems to be targeted for instance in the field of imaging, optical communications or biomedical sensing. In this review, after a brief resume of photogeneration basics and of devices operation mechanisms, we offer a broad overview of recent progress in the field, focusing on photodiodes and phototransistors. As to the former device category, very interesting values for figures of merit such as photoconversion efficiency, speed and minimum detectable signal level have been attained, and even though the simultaneous optimization of all these relevant parameters is demonstrated in a limited number of papers, real applications are within reach for this technology, as it is testified by the increasing number of realizations going beyond the single-device level and tackling more complex optoelectronic systems. As to phototransistors, a more recent subject of study in the framework of organic electronics, despite a broad distribution in the reported performances, best photoresponsivities outperform amorphous silicon-based devices. This suggests that organic phototransistors have a large potential to be used in a variety of optoelectronic peculiar applications, such as a photo-sensor, opto-isolator, image sensor, optically controlled phase shifter, and opto-electronic switch and memory. PMID:23483718
Baeg, Kang-Jun; Binda, Maddalena; Natali, Dario; Caironi, Mario; Noh, Yong-Young
Compact multispectral photodiode arrays using micropatterned dichroic filters
NASA Astrophysics Data System (ADS)
The next generation of multispectral instruments requires significant improvements in both spectral band customization and portability to support the widespread deployment of application-specific optical sensors. The benefits of spectroscopy are well established for numerous applications including biomedical instrumentation, industrial sorting and sensing, chemical detection, and environmental monitoring. In this paper, spectroscopic (and by extension hyperspectral) and multispectral measurements are considered. The technology, tradeoffs, and application fits of each are evaluated. In the majority of applications, monitoring 4-8 targeted spectral bands of optimized wavelength and bandwidth provides the necessary spectral contrast and correlation. An innovative approach integrates precision spectral filters at the photodetector level to enable smaller sensors, simplify optical designs, and reduce device integration costs. This method supports user-defined spectral bands to create application-specific sensors in a small footprint with scalable cost efficiencies. A range of design configurations, filter options and combinations are presented together with typical applications ranging from basic multi-band detection to stringent multi-channel fluorescence measurement. An example implementation packages 8 narrowband silicon photodiodes into a 9x9mm ceramic LCC (leadless chip carrier) footprint. This package is designed for multispectral applications ranging from portable color monitors to purpose- built OEM industrial and scientific instruments. Use of an eight-channel multispectral photodiode array typically eliminates 10-20 components from a device bill-of-materials (BOM), streamlining the optical path and shrinking the footprint by 50% or more. A stepwise design approach for multispectral sensors is discussed - including spectral band definition, optical design tradeoffs and constraints, and device integration from prototype through scalable volume production. Additional customization options are explored for application-specific OEM sensors integrated into portable devices using multispectral photodiode arrays.
Chandler, Eric V.; Fish, David E.
Single-Crystalline Silicon-Based Heterojunction Photodiode Arrays on Flexible Plastic Substrates
A silicon-based photodiode array was fabricated on a flexible polyethylene terephthalate substrate using a trans- fer printing technique. A heterojunction structure composed of a 15-nm-thick highly doped hydrogenated amorphous-silicon (n + a-Si:H) layer and a 3-�m-thick p-type single-crystal silicon (p c-Si) membrane layer was adopted as the active layer of the flexible photodiode. The highly ordered photodiode array formed on
Sangwook Lee; Juree Hong; Ja Hoon Koo; Seulah Lee; Kwanghyun Lee; Seongil Im; Taeyoon Lee
Nano-Multiplication-Region Avalanche Photodiodes and Arrays
NASA Technical Reports Server (NTRS)
Nano-multiplication-region avalanche photodiodes (NAPDs), and imaging arrays of NAPDs integrated with complementary metal oxide/semiconductor (CMOS) active-pixel-sensor integrated circuitry, are being developed for applications in which there are requirements for high-sensitivity (including photoncounting) detection and imaging at wavelengths from about 250 to 950 nm. With respect to sensitivity and to such other characteristics as speed, geometric array format, radiation hardness, power demand of associated circuitry, size, weight, and robustness, NAPDs and arrays thereof are expected to be superior to prior photodetectors and arrays including CMOS active-pixel sensors (APSs), charge-coupled devices (CCDs), traditional APDs, and microchannelplate/ CCD combinations. Figure 1 depicts a conceptual NAPD array, integrated with APS circuitry, fabricated on a thick silicon-on-insulator wafer (SOI). Figure 2 presents selected aspects of the structure of a typical single pixel, which would include a metal oxide/semiconductor field-effect transistor (MOSFET) integrated with the NAPD. The NAPDs would reside in silicon islands formed on the buried oxide (BOX) layer of the SOI wafer. The silicon islands would be surrounded by oxide-filled insulation trenches, which, together with the BOX layer, would constitute an oxide embedding structure. There would be two kinds of silicon islands: NAPD islands for the NAPDs and MOSFET islands for in-pixel and global CMOS circuits. Typically, the silicon islands would be made between 5 and 10 m thick, but, if necessary, the thickness could be chosen outside this range. The side walls of the silicon islands would be heavily doped with electron-acceptor impurities (p+-doped) to form anodes for the photodiodes and guard layers for the MOSFETs. A nanoscale reach-through structure at the front (top in the figures) central position of each NAPD island would contain the APD multiplication region. Typically, the reach-through structure would be about 0.1 microns in diameter and between 0.3 and 0.4 nm high. The top layer in the reach-through structure would be heavily doped with electron-donor impurities (n+-doped) to make it act as a cathode. A layer beneath the cathode, between 0.1 and 0.2 nm thick, would be p-doped to a concentration .10(exp 17)cu cm. A thin n+-doped polysilicon pad would be formed on the top of the cathode to protect the cathode against erosion during a metal-silicon alloying step that would be part of the process of fabricating the array.
Zheng, Xinyu; Pain, Bedabrata; Cunningham, Thomas
Calibration of a Photodiode Array Spectrometer Against the Copper Point
NASA Astrophysics Data System (ADS)
This paper describes a method to calibrate photodiode array spectrometers in the spectral radiance mode using a fixed-point blackbody as a reference source. Fixed-point blackbodies are characterized by their excellent emissivity, uniformity, and stability, which make them superior to both conventional standard lamps and variable temperature blackbodies. The temperature of these fixed points is accurately determined being traceable to either the International Temperature Scale (ITS-90) or thermodynamically through radiometric standards. The potential advantage of the fixed-point traceability chain is that it can be universally reproduced without recourse to any hierarchical calibrations or standards. The paper presents the calibration system and discusses the limitations of such an approach. The method used obtained an uncertainty of around 1.4 % () associated with radiance responsivity across the spectral region from 550 nm to 1050 nm, which is comparable to what is readily achieved with a lamp-tile or lamp-illuminated spherical source.
Salim, S. G. R.; Woolliams, E. R.; Fox, N. P.
High resolution, low energy avalanche photodiode X-ray detectors
NASA Technical Reports Server (NTRS)
Silicon avalanche photodiodes have been fabricated, and their performance as X-ray detectors has been measured. Photon sensitivity and energy resolution were measured as a function of size and operating parameters. Noise thresholds as low as 212 eV were obtained at room temperature, and backscatter X-ray fluorescence data were obtained for aluminum and other light elements. It is concluded that the results with the X-ray detector are extremely encouraging, and the performance is challenging the best available proportional counters. While not at the performance level of either cryogenic silicon or HgI2, these device operate at room temperature and can be reproduced in large numbers and with much larger areas than typically achieved with HgI2. In addition, they are rugged and appear to be indefinitely stable.
Farrell, R.; Vanderpuye, K.; Entine, G.; Squillante, M. R.
Linear array of photodiodes to track a human speaker for video recording
NASA Astrophysics Data System (ADS)
Communication and collaboration using stored digital media has garnered more interest by many areas of business, government and education in recent years. This is due primarily to improvements in the quality of cameras and speed of computers. An advantage of digital media is that it can serve as an effective alternative when physical interaction is not possible. Video recordings that allow for viewers to discern a presenter's facial features, lips and hand motions are more effective than videos that do not. To attain this, one must maintain a video capture in which the speaker occupies a significant portion of the captured pixels. However, camera operators are costly, and often do an imperfect job of tracking presenters in unrehearsed situations. This creates motivation for a robust, automated system that directs a video camera to follow a presenter as he or she walks anywhere in the front of a lecture hall or large conference room. Such a system is presented. The system consists of a commercial, off-the-shelf pan/tilt/zoom (PTZ) color video camera, a necklace of infrared LEDs and a linear photodiode array detector. Electronic output from the photodiode array is processed to generate the location of the LED necklace, which is worn by a human speaker. The computer controls the video camera movements to record video of the speaker. The speaker's vertical position and depth are assumed to remain relatively constant- the video camera is sent only panning (horizontal) movement commands. The LED necklace is flashed at 70Hz at a 50% duty cycle to provide noise-filtering capability. The benefit to using a photodiode array versus a standard video camera is its higher frame rate (4kHz vs. 60Hz). The higher frame rate allows for the filtering of infrared noise such as sunlight and indoor lighting-a capability absent from other tracking technologies. The system has been tested in a large lecture hall and is shown to be effective.
DeTone, D.; Neal, H.; Lougheed, R.
Nano-multiplication region avalanche photodiodes and arrays
NASA Technical Reports Server (NTRS)
An avalanche photodiode with a nano-scale reach-through structure comprising n-doped and p-doped regions, formed on a silicon island on an insulator, so that the avalanche photodiode may be electrically isolated from other circuitry on other silicon islands on the same silicon chip as the avalanche photodiode. For some embodiments, multiplied holes generated by an avalanche reduces the electric field in the depletion region of the n-doped and p-doped regions to bring about self-quenching of the avalanche photodiode. Other embodiments are described and claimed.
Zheng, Xinyu (Inventor); Pain, Bedabrata (Inventor); Cunningham, Thomas J. (Inventor)
X-ray pixel array detectors (PADs) are generally thought of as either digital photon counters (DPADs) or X-ray analog-integrating pixel array detectors (APADs). Experiences with APADs, which are especially well suited for X-ray imaging experiments where transient or high instantaneous flux events must be recorded, are reported. The design, characterization and experimental applications of several APAD designs developed at Cornell University are discussed. The simplest design is a ;flash' architecture, wherein successive integrated X-ray images, as short as several hundred nanoseconds in duration, are stored in the detector chips for later off-chip digitization. Radiography experiments using a prototype flash APAD are summarized. Another design has been implemented that combines flash capability with the ability to continuously stream X-ray images at slower (e.g. milliseconds) rates. Progress is described towards radiation-hardened APADs that can be tiled to cover a large area. A mixed-mode PAD, design by combining many of the attractive features of both APADs and DPADs, is also described. PMID:16495611
Ercan, A; Tate, M W; Gruner, S M
Solid state neutron detector array
A neutron detector array is capable of measuring a wide range of neutron fluxes. The array includes multiple semiconductor neutron detectors. Each detector has a semiconductor active region that is resistant to radiation damage. In one embodiment, the array preferably has a relatively small size, making it possible to place the array in confined locations. The ability of the array to detect a wide range of neutron fluxes is highly advantageous for many applications such as detecting neutron flux during start up, ramp up and full power of nuclear reactors.
Seidel, John G. (Pittsburgh, PA); Ruddy, Frank H. (Monroeville, PA); Brandt, Charles D. (Mount Lebanon, PA); Dulloo, Abdul R. (Pittsburgh, PA); Lott, Randy G. (Pittsburgh, PA); Sirianni, Ernest (Monroeville, PA); Wilson, Randall O. (Greensburg, PA)
Solid state neutron detector array
A neutron detector array is capable of measuring a wide range of neutron fluxes. The array includes multiple semiconductor neutron detectors. Each detector has a semiconductor active region that is resistant to radiation damage. In one embodiment, the array preferably has a relatively small size, making it possible to place the array in confined locations. The ability of the array to detect a wide range of neutron fluxes is highly advantageous for many applications such as detecting neutron flux during start up, ramp up and full power of nuclear reactors. 7 figs.
Seidel, J.G.; Ruddy, F.H.; Brandt, C.D.; Dulloo, A.R.; Lott, R.G.; Sirianni, E.; Wilson, R.O.
High-Power InP-based Waveguide Photodiodes and Photodiode Arrays Heterogeneously Integrated on SOI
evanescently-coupled modified uni-traveling carrier photodiodes (MUTC PDs) on silicon-on-insulator (SOI the potential to achieve low dark current, high saturation current and wideband absorption over C- and L waveguides followed by transferring the III-V wafer to the patterned SOI/Si substrate through low
Bowers, John
Analysis of flavonoids from lotus (Nelumbo nucifera) leaves using high performance liquid chromatography/photodiode array detector tandem electrospray ionization mass spectrometry and an extraction method optimized by orthogonal design.
The extraction protocol of flavonoids from lotus (Nelumbo nucifera) leaves was optimized through an orthogonal design. The solvent was the most important factor comparing solvent, solvent:tissue ratio, extraction time, and temperature. The highest yield of flavonoids was achieved with 70% methanol-water and a solvent:tissue ratio of 30:1 at 4 �C for 36 h. The optimized analytical method for HPLC was a multi-step gradient elution using 0.5% formic acid (A) and CH?CN containing 0.1% formic acid (B), at a flow rate of 0.6 mL/min. Using this optimized method, thirteen flavonoids were simultaneously separated and identified by high performance liquid chromatography coupled with photodiode array detection/electrospray ionization mass spectrometry (HPLC/DAD/ESI-MS(n)). Five of the bioactive compounds are reported in lotus leaves for the first time. The flavonoid content of the leaves of three representative cultivars was assessed under the optimized extraction and HPLC analytical conditions, and the seed-producing cultivar 'Baijianlian' had the highest flavonoid content compared with rhizome-producing 'Zhimahuoulian' and wild floral cultivar 'Honglian'. PMID:22265782
Chen, Sha; Wu, Ben-Hong; Fang, Jin-Bao; Liu, Yan-Ling; Zhang, Hao-Hao; Fang, Lin-Chuan; Guan, Le; Li, Shao-Hua
Characterization of avalanche photodiodes for lidar atmospheric return signal detectors
NASA Technical Reports Server (NTRS)
Results are presented from tests to characterize noise, dark current, overload, and gain versus bias, relationships of ten avalanche photodiodes. The advantages of avalanche photodiodes over photomultiplier tubes for given laser wavelengths and return signal amplitudes are outlined. The relationship between responsivity and temperature and dark current and temperature are examined. Also, measurements of the noise equivalent power, the excess noise factor, and linearity are given. The advantages of using avalanche photodiodes in the Lidar Atmospheric Sensing Experiment and the Lidar In-Space Technology Experiment are discussed.
Antill, C. W., Jr.; Holloway, R. M.
Development of a large pixel, spectrally optimized, pinned photodiode/interline charge coupled device (CCD) detector for the Earth Observing System (EOS)/Moderate-Resolution Imaging Spectrometer-Tilt (MODIS-T) instrument
NASA Technical Reports Server (NTRS)
A pinned photodiode/interline CCD Detector Array is under development for the EOS/MODIS-T project. Outstanding features of the device include large pixels, spectrally optimized fill factors, and blooming protection. The detector has 30 spatial rows and 32 spectral columns. The device layout is split into two halves; each half has its own detector area, storage area, and output structure.
Ewin, Audrey J.; Jhabvala, Murzy; Shu, Peter K.
64-element photodiode array for scintillation detection of x-rays
NASA Astrophysics Data System (ADS)
The paper presents the design, technology and parameters of a new, silicon 64-element linear photodiode array developed at the Institute of Electron Technology (ITE) for the detection of scintillations emitted by CsI scintillators (??550 nm). The arrays are used in a device for examining the content of containers at border crossings under development at the National Centre for Nuclear Research. Two arrays connected with a scintillator block (128 CsI scintillators) form a 128-channel detection module. The array consists of 64 epiplanar photodiode structures (5.1 � 7.2 mm) and a 5.3 mm module. p+-?-n+ photodiode structures are optimised for the detection of radiation of ?? 550 nm wavelength with no voltage applied (photovoltaic mode). The structures are mounted on an epoxy-glass laminate substrate, copper-clad on both sides, on which connections with a common anode and separate cathode leads are located. The photosensitive surface of photodiodes is covered with a special silicone gel, which protects photodiodes against the mechanical impact of scintillators
Wegrzecki, Maciej; Wolski, Dariusz; Bar, Jan; Budzy?ski, Tadeusz; Ch?opik, Arkadiusz; Grabiec, Piotr; K?os, Helena; Panas, Andrzej; Piotrowski, Tadeusz; S?ysz, Wojciech; Stolarski, Maciej; Szmigiel, Dariusz; Wegrzecka, Iwona; Zaborowski, Micha?
Development of a photodiode array biochip using a bipolar semiconductor and its application to detection of human papilloma virus
We describe a DNA microarray system using a bipolar integrated circuit photodiode array (PDA) chip as a new platform for DNA\\u000a analysis. The PDA chip comprises an 8?�?6 array of photodiodes each with a diameter of 600�?m. Each photodiode element acts\\u000a both as a support for an immobilizing probe DNA and as a two-dimensional photodetector. The usefulness of the PDA
Taek Jin Baek; Pan Yun Park; Kwi Nam Han; Ho Taik Kwon; Gi Hun Seong
A microwave detector based on an MCT photodiode for subthermonuclear plasma research
A microwave detector including a single-element infrared (IR) photodiode mounted in a cooled Dewar and a preamplifier is developed.\\u000a An IR photodiode of the n\\u000a +-p type is created on the basis of mercury-cadmium telluride (HgCdTe or MCT) heteroepitaxial structures grown by means of molecular\\u000a beam epitaxy. A special profile of MCT structures throughout the MCT layer thickness ensures a
V. V. Vasilyev; S. A. Dvoretsky; V. S. Varavin; N. N. Mikhailov; I. V. Marchishin; Yu. G. Sidorov; A. O. Suslyakov; V. N. Ovsyuk; V. S. Burmasov; S. S. Popov; E. P. Kruglyakov; A. L. Aseev
Advanced UV Detectors and Detector Arrays
NASA Technical Reports Server (NTRS)
Gallium Nitride (GaN) with its wide energy bandgap of 3.4 eV holds excellent promise for solar blind UV detectors. We have successfully designed, fabricated and tested GaN p-i-n detectors and detector arrays. The detectors have a peak responsivity of 0.14A/W at 363 nm (3.42 eV) at room temperature. This corresponds to an internal quantum efficiency of 56%. The responsivity decreases by several orders of magnitude to 0.008 A/W at 400 nm (3.10 eV) giving the excellent visible rejection ratio needed for solar-blind applications.
Pankove, Jacques I.; Torvik, John
Initial characterization of a bgo-Photodiode detector for high resolution positron emission tomography
Spatial resolution in positron emission tomography is currently limited by the resolution of the detectors. This work presents the initial characterization of a detector design using small bismuth germanate (BGO) crystals individually coupled to silicon photodiodes (SPDs) for crystal identification, and coupled in groups to phototubes (PMTs) for coincidence timing. A 3 mm x 3 mm x 3 mm BGO
Stephen E. Derenzo
A bench-top megavoltage fan-beam CT using CdWO4-photodiode detectors. I. System description and detector characterization.
We describe the components of a bench-top megavoltage computed tomography (MVCT) scanner that uses an 80-element detector array consisting of CdWO4 scintillators coupled to photodiodes. Each CdWO4 crystal is 2.75 x 8 x 10 mm3. The detailed design of the detector array, timing control, and multiplexer are presented. The detectors show a linear response to dose (dose rate was varied by changing the source to detector distance) with a correlation coefficient (R2) nearly unity with the standard deviation of signal at each dose being less than 0.25%. The attenuation of a 6 MV beam by solid water measured by this detector array indicates a small, yet significant spectral hardening that needs to be corrected before image reconstruction. The presampled modulation transfer function is strongly affected by the detector's large pitch and a large improvement can be obtained by reducing the detector pitch. The measured detective quantum efficiency at zero spatial frequency is 18.8% for 6 MV photons which will reduce the dose to the patient in MVCT applications. The detector shows a less than a 2% reduction in response for a dose of 24.5 Gy accumulated in 2 h; however, the lost response is recovered on the following day. A complete recovery can be assumed within the experimental uncertainty (standard deviation <0.5%); however, any smaller permanent damage could not be assessed. PMID:16696485
Rathee, S; Tu, D; Monajemi, T T; Rickey, D W; Fallone, B G
Detector Arrays For Infrared Astronomy
NASA Technical Reports Server (NTRS)
Paper describes status of program for developing integrated infrared detectors for astronomy. Program covers variety of detectors, including extrinsic silicon, extrinsic germanium, and indium antimonide devices with hybrid silicon multiplexers. Paper notes for arrays to reach background noise limit in cryogenic telescope, continued reductions in readout noise and dark current needed.
Mccreight, C. R.; Mckelvey, M. E.; Goebel, J. H.; Anderson, G. M.; Lee, J. H.
Versatile Silicon Photodiode Detector Technology for Scanning Electron Microscopy with High-Efficiency Sub-5 keV Electron Detection
Versatile Silicon Photodiode Detector Technology for Scanning Electron Microscopy with High: +31 (0)15 26 22163, Email: email@example.com Abstract A new silicon electron detector technology for Scanning Electron Microscopy, based on ultrashallow p+ n boron-layer photodiodes, features nm-thin anodes
Technische Universiteit Delft
A prototype high-resolution animal positron tomograph with avalanche photodiode arrays and LSO crystals
To fully utilize positron emission tomography (PET) as a non-invasive tool for tissue characterization, dedicated instrumentation is being developed which is specially suited for imaging mice and rats. Semiconductor detectors, such as avalanche photodiodes (APDs), may offer an alternative to photomultiplier tubes for the readout of scintillation crystals. Since the scintillation characteristics of lutetium oxyorthosilicate (LSO) are well matched to
Sibylle I. Ziegler; Bernd J. Pichler; Guido Boening; Magdalena Rafecas; Wendelin Pimpl; Eckart Lorenz; Norbert Schmitz; Markus Schwaiger
Noise characteristics of avalanche photodiode arrays of the bevel-edge type
A calculation of the noise characteristics beveled-edge avalanche photodiode arrays is presented. It describes well the observed results from 61-element arrays with 1.2�1.2 mm2 and 0.45�0.45 mm2 pixel size. The main source of noise at low gain is Johnson noise from the interpixel resistance. At high gain, the shot noise from the bulk dark current dominates. There is an intermediate
Ernesto Gramsch
Electrical crosstalk in front-illuminated photodiode array with different guard ring designs for medical CT applications
This paper presents electrical crosstalk studies on front-illuminated photodiode arrays for medical computed tomography (CT) applications. Crosstalk is an important factor to the system noise and image quality. The electrical crosstalk depends on silicon substrate properties and photodiode structures. The photodiode samples employed in this paper are planar processed on high-resistivity n-type silicon substrate, resulting in a p+\\/n?\\/n+ diode structure.
Fan Ji; Mikko Juntunen; Iiro Hietanen
CMOS Geiger photodiode array with integrated signal processing for imaging of 2D objects using quantum dots
NASA Astrophysics Data System (ADS)
Geiger-mode photodiodes (GPD) act as binary photon detectors that convert analog light intensity into digital pulses. Fabrication of arrays of GPD in a CMOS environment simplifies the integration of signal-processing electronics to enhance the performance and provide a low-cost detector-on-a-chip platform. Such an instrument facilitates imaging applications with extremely low light and confined volumes. High sensitivity reading of small samples enables twodimensional imaging of DNA arrays and for tracking single molecules, and observing their dynamic behavior. In this work, we describe the performance of a prototype imaging detector of GPD pixels, with integrated active quenching for use in imaging of 2D objects using fluorescent labels. We demonstrate the integration of on-chip memory and a parallel readout interface for an array of CMOS GPD pixels as progress toward an all-digital detector on a chip. We also describe advances in pixel-level signal processing and solid-state photomultiplier developments.
Stapels, Christopher J.; Lawrence, William G.; Gurjar, Rajan S.; Johnson, Erik B.; Christian, James F.
Development of compact radiation detectors based on MAPD photodiodes with Lutetium Fine Silicate and stilbene scintillators
NASA Astrophysics Data System (ADS)
Results of gamma-ray measurements taken with Lutetium Fine Silicate (LFS) scintillators and Micro-Pixel Avalanche Photodiodes (MAPD) are presented in the energy range of 59.6 keV to 834.8 keV . Dependences of energy resolution on gamma-ray energy are studied. Results of several measurements are discussed to assess the performance of gamma ray source identification of the developed detector. The alpha particle and neutron detection performance of LFS and stilbene scintillators coupled to micro-pixel avalanche photodiode are discussed as well.
Ahmadov, F.; Ahmadov, G.; Abdullaev, X.; Garibov, A.; Guliyev, E.; Khorev, S.; Madatov, R.; Muxtarov, R.; Naghiyev, J.; Sadigov, A.; Sadygov, Z.; Suleymanov, S.; Zerrouk, F.
Effect of different drying methods on the quality of Angelicae Sinensis Radix evaluated through simultaneously determining four types of major bioactive components by high performance liquid chromatography photodiode array detector and ultra-high performance liquid chromatography quadrupole time-of-flight mass spectrometry.
In the present study, the effect of drying methods on the quality of Angelicae Sinensis Radix (DG), was evaluated by newly developed high performance liquid chromatography photodiode array detector (HPLC-DAD) and ultra-high performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS/MS). Ten major bioactive components including two phenolic acids, two hydroxyl phthalides, four alkyl phthalides and two phthalide dimers were selected as evaluation chemical markers and the newly-established method was qualitatively and quantitatively validated. DG slices and whole roots dried in shade, sun light, hot air, vacuum, microwave, far infrared ray and combination of microwave and far infrared ray as well as the fresh DG samples were determined by the established methods. DG slices dried in hot air kept the similar chemical composition to that of fresh DG, while DG whole roots dried in vacuum retained highest contents of the major components. Coniferyl ferulate and ligustilide degraded significantly in DG slices dried by microwave, far infrared ray and their combination. The influence of such chemical changes induced by different drying methods on the bioactivities of DG warrants further investigation, so that the optimal drying method can be obtained for the standardization of DG herb. PMID:24561333
Bai, Ying-Jia; Kong, Ming; Xu, Jin-Di; Zhang, Xiao-Lin; Zhou, Shan-Shan; Wang, Xiao-Ning; Liu, Li-Fang; Li, Song-Lin
Avalanche photodiode array sensor with high-speed CCD delay line readout
NASA Astrophysics Data System (ADS)
A prototype solid-state multi-chip-module (MCM) optical sensor circuit is described. The MCM is designed to sample the optical signals from a fiber-optic array at rates up to 200 MHz. The fiber-optic inputs interface to the MCM avalanche-photodiode (APD) sensor array. The prototype 40 pixel MCM stores approximately 1000 samples from each fiber before readout. This is done on the MCM using high-speed charge-injection input CCD delay line ICs. The MCM is designed to be cooled to 0 degrees C. This stabilizes the APD gain and minimizes dark current generation in the APD and the CCD delay line.
Albright, Kevin L.; Bradley, Jeffrey M.
A new silicon avalanche photodiode photon counting detector module for astronomy
A new Silicon avalanche photodiode photon counting detector module with a peak detection efficiency of 45% and a maximum counting rate of more than 3,000,000cts\\/sec is described and its performance assessed over a range of operating conditions. The module should prove ideal for a wide variety of astronomical instrumentation as it covers the spectral range 350�1050nm and is compact, rugged
N. S. Nightingale; Cavendish Labomtov
Development of a testbed for flexible a-Si:H photodiode sensing arrays
NASA Astrophysics Data System (ADS)
Large area, flexible sensing arrays for imaging, biochemical sensing and radiation detection are now possible with the development of flexible active matrix display technology. In particular, large-area flexible imaging arrays can provide considerable advancement in defense and security industries because of their inherent low manufacturing costs and physical plasticity that allows for increased adaptability to non-planar mounting surfaces. For example, a flexible array of photodetectors and lenslets formed into a cylinder could image simultaneously with a 360 degree view without the need for expensive bulky optics or a gimbaled mount. Here we report the design and development of a scalable 16x16 pixel testbed for flexible sensor arrays using commercial-off-the-shelf (COTS) parts and demonstrate the capture of a shadow image with an array of photodiodes and active pixel sensors on a plastic substrate. The image capture system makes use of an array of low-noise, InGaZnO active pixel amplifiers to detect changes in current in 2.4 ?m-thick reverse-biased a-Si:H PIN diodes. A thorough characterization of the responsivity, detectivity, and optical gain of an a- Si:H photodiode is also provided. At the back end, analog capture circuitry progressively scans the array and constructs an image based on the electrical activity in each pixel. The use of correlated-double-sampling to remove fixed pattern noise is shown to significantly improve spatial resolution due to process variations. The testbed can be readily adapted for the development of neutron, alpha-particle, or X-ray detection arrays given an appropriate conversion layer.
Dominguez, Alfonso; Kunnen, George; Vetrano, Michael; Smith, Joseph; Marrs, Michael; Allee, David R.
Determination of bixin and norbixin in meat using liquid chromatography and photodiode array detection.
The development of an analytical method that enables routine analysis of annatto dye, specifically bixin and norbixin, in meat tissue is described. Liquid-solid extraction was carried out using acetonitrile. Analysis was by HPLC with photodiode array detection using two fixed wavelengths (458 and 486 nm). The possibilities of ion trap mass spectrometry (MS) were also assessed. Method performance characteristics, according to Commission Decision 2002/657/EC, were determined, with recoveries between 99 and 102% and calibration curves being linear in the 0.5-10 mg kg(-1) range. The limit of quantification was 0.5 mg kg(-1). PMID:19680866
Noppe, H; Abuin Martinez, S; Verheyden, K; Van Loco, J; Companyo Beltran, R; De Brabander, H F
Initial characterization of a position-sensitive photodiode/BGO detector for PET (positron emission tomography)
We present initial results of a position-sensitive photodiode/BGO detector for high resolution, multi-layer positron emission tomography (PET). Position sensitivity is achieved by dividing the 3 mm /times/ 20 mm rectangular photosensitive area along the diagonal to form two triangular segments. Each segment was individually connected to a low-noise amplifier. The photodiodes and crystals were cooled to /minus/100/degree/C to reduce dark current and increase the BGO signal. With an amplifier peaking time of 17 ..mu..sec, the sum of the signals (511 keV photopeak) was 3200 electrons with a full width at half maximum (fwhm) of 750 electrons. The ratio of one signal to the sum determined the depth of interaction with a resolution of 11 mm fwhm. 27 refs., 7 figs.
Derenzo, S.E.; Moses, W.W.; Jackson, H.G.; Turko, B.T.; Cahoon, J.L.; Geyer, A.B.; Vuletich, T.
Arrays of Bolometric Detectors for Submillimeter Astronomy
NASA Technical Reports Server (NTRS)
Large format two dimensional arrays of bolometric detectors are required for many millimeter and submillimeter applications. We describe the development and testing of such arrays and the plans for using them in both a ground-based and airborne instrument.
Silverberg, R. F.; Moseley, S. H.; Freund, M.; Allen, C.; Harper, A.; Loewenstein, R.; Dowell, C. D.; Fisher, Richard R. (Technical Monitor)
A linear photodiode array employed in a short range laser triangulation obstacle avoidance sensor. M.S. Thesis; [Martian roving vehicle sensor
NASA Technical Reports Server (NTRS)
An opto-electronic receiver incorporating a multi-element linear photodiode array as a component of a laser-triangulation rangefinder was developed as an obstacle avoidance sensor for a Martian roving vehicle. The detector can resolve the angle of laser return in 1.5 deg increments within a field of view of 30 deg and a range of five meters. A second receiver with a 1024 elements over 60 deg and a 3 meter range is also documented. Design criteria, circuit operation, schematics, experimental results and calibration procedures are discussed.
Odenthal, J. P.
Predictions of silicon avalanche photodiode detector performance in water vapor differential absorption lidar
NASA Technical Reports Server (NTRS)
Performance analyses are presented which establish that over most of the range of signals expected for a down-looking differential absorption lidar (DIAL) operated at 16 km the silicon avalanche photodiode (APD) is the preferred detector for DIAL measurements of atmospheric water vapor in the 730 nm spectral region. The higher quantum efficiency of the APD's, (0.8-0.9) compared to a photomultiplier's (0.04-0.18) more than offsets the higher noise of an APD receiver. In addition to offering lower noise and hence lower random error the APD's excellent linearity and impulse recovery minimize DIAL systematic errors attributable to the detector. Estimates of the effect of detector system parameters on overall random and systematic DIAL errors are presented, and performance predictions are supported by laboratory characterization data for an APD receiver system.
Kenimer, R. L.
Evaluation of a PIN Photodiode Detector in Neutron-Gamma Fields
NASA Astrophysics Data System (ADS)
Semiconductor detectors are suitable for applications in radiation dosimetry in nuclear research reactors and for radiation protection purposes. The performance of these detectors depends on the quality of their semiconductor. The aim of this work was to evaluate a commercial PIN Photodiode in the neutron-gamma fields of the IEA-R1 nuclear research reactor and from an AmBe neutron source. This semiconductor was studied as a neutron detector using some types of converters to determine a dose-to-counts conversion factor to dose equivalent. The results have shown that this component may be implemented for assessing the neutron spectra in some radiation fields and in dose equivalent in radiation protection routines.
C�rdenas, Jos� Patricio N.; Campos, Let�cia L.; Filho, Tufic Madi
Optoelectronic measurement for parameters of high-speed flying objects based on laser screen and photodiode array
NASA Astrophysics Data System (ADS)
The impacting or penetrating power of high-speed flying object can be evaluated by its mass and velocity, so the velocity and the mass are two key parameters. Here we present an optoelectronic measurement method for parameters of high-speed flying objects based on parallel laser screen and photodiode array. The system consists of two thin laser screens with parallel each other and certain distance, orthogonal two dimensional photodiode arrays, data acquisition module, control module and data transmission processing module. When the object flies through the thin screen, the incident light of some photodiodes at the corresponding position is blocked and the output states of the corresponding photodiodes are changed. The flying position, which can be used to correct the distance error, velocity and the overall dimension of the object are determined by high-speed sampling and storing all the output states of photodiode array at any sampling moment when the object flying through the thin screens. We employed a line-shaped laser diode and a Fresnel lens with long-focal-length and aberration-free to generate parallel laser screen. The high-speed large-amount parallel data sampling module is comprised of four FPGA-based boards with built-in FIFO buffer memory, and the control module is constructed by one FPGA board and a FLASH memory. Functions simulation and experiment results of the FPGA-based data acquisition storage and the LabVIEW-based data processing indicate that the method and the design are feasible.
Zhao, Donge; Zhang, Bin; Liu, Ji; Xiao, Kai-jia; Wang, Lei
NASA Technical Reports Server (NTRS)
Highlights of the results obtained on arsenic-doped silicon blocked impurity band (BIB) detectors and arrays since the invention of the BIB concept a few years ago are presented. After a brief introduction and a description of the BIB concept, data will be given on single detector performance. Then different arrays that were fabricated will be described and test data presented.
Bharat, R.; Petroff, M. D.; Speer, J. J.; Stapelbroek, M. G.
Junction-side illuminated silicon detector arrays
A junction-side illuminated detector array of pixelated detectors is constructed on a silicon wafer. A junction contact on the front-side may cover the whole detector array, and may be used as an entrance window for light, x-ray, gamma ray and/or other particles. The back-side has an array of individual ohmic contact pixels. Each of the ohmic contact pixels on the back-side may be surrounded by a grid or a ring of junction separation implants. Effective pixel size may be changed by separately biasing different sections of the grid. A scintillator may be coupled directly to the entrance window while readout electronics may be coupled directly to the ohmic contact pixels. The detector array may be used as a radiation hardened detector for high-energy physics research or as avalanche imaging arrays.
Iwanczyk, Jan S.; Patt, Bradley E.; Tull, Carolyn
Apparatus and method for heterodyne-generated two-dimensional detector array using a single element detector
Apparatus and method are disclosed for heterodyne-generated, two-dimensional detector array using a single detector. Synthetic-array heterodyne detection, permits a single-element optical detector to behave as though it were divided into an array of separate heterodyne detector elements. A fifteen-element synthetic array has successfully been experimentally realized on a single-element detector, permitting all of the array elements to be read out continuously and in parallel from one electrical connection. A CO{sub 2} laser and a single-element HgCdTe photodiode are employed. A different heterodyne local oscillator frequency is incident upon the spatially resolvable regions of the detector surface. Thus, different regions are mapped to different heterodyne beat frequencies. One can determine where the photons were incident on the detector surface even though a single electrical connection to the detector is used. This also prevents the destructive interference that occurs when multiple speckles are imaged (similar to spatial diversity), In coherent LIDAR this permits a larger field of view. An acoustooptic modulator generates the local oscillator frequencies and can achieve adequate spatial separation of optical frequencies of the order of a megahertz apart. 4 figs.
Strauss, C.E.
Apparatus and method for heterodyne-generated two-dimensional detector array using a single element detector
Apparatus and method for heterodyne-generated, two-dimensional detector array using a single detector. Synthetic-array heterodyne detection, permits a single-element optical detector to behave as though it were divided into an array of separate heterodyne detector elements. A fifteen-element synthetic array has successfully been experimentally realized on a single-element detector, permitting all of the array elements to be read out continuously and in parallel from one electrical connection. A CO.sub.2 laser and a single-element HgCdTe photodiode are employed. A different heterodyne local oscillator frequency is incident upon the spatially resolvable regions of the detector surface. Thus, different regions are mapped to different heterodyne beat frequencies. One can determine where the photons were incident on the detector surface even though a single electrical connection to the detector is used. This also prevents the destructive interference that occurs when multiple speckles are imaged (similar to spatial diversity), In coherent LIDAR this permits a larger field of view. An acoustooptic modulator generates the local oscillator frequencies and can achieve adequate spatial separation of optical frequencies of the order of a megahertz apart.
Strauss, Charlie E. (Santa Fe, NM)
Infrared array detectors. [for astronomical observation
NASA Technical Reports Server (NTRS)
Arrays of detectors sensitive to infrared radiation will enable astronomical observations to be made with shorter observing times than with discrete detectors and with good relative spatial accuracy. Systems using such arrays are being developed for astronomy in several regions of the electromagnetic spectrum. An example of an infrared system is given here consisting of a 32x32 element bismuth doped silicon charge injection device array that has been used in an astronomical camera.
Arens, J. F.
Large Format Detector Arrays for Astrophysics
NASA Technical Reports Server (NTRS)
Improvements in detector design and advances in fabrication techniques has resulted in devices which can reach fundamental sensitivity limits in many cases. Many pressing astrophysical questions require large arrays of such sensitive detectors. I will describe the state of far infrared through millimeter detector development at NASA/GSFC, the design and production of large format arrays, and the initial deployment of these powerful new tools.
Moseley, Harvey
Determination of acaricides in honey by high-performance liquid chromatography with photodiode array detection.
Rapid analytical methods are described to control quality of honeys, concerning residues of acaricides applied in hives to prevent Varroa jacobsoni infestation. A liquid-liquid extraction with hexane-propanol-2-ammonia (60 ml:30 ml:0.28%) was used for the simultaneous analysis of coumaphos, bromopropylate, amitraz and fluvalinate. For thymol, one clean up on a solid-phase extraction C18 (500 mg, 6 ml) column was performed; for rotenone, a liquid extraction with dichloromethane was realised. Quantitative recoveries obtained with honey were satisfactory and were superior to 80%. All acaricides are identified by reversed-phase high-performance liquid chromatography with photodiode array detection. Quantification limits obtained were below maximal residue limits when these exist. PMID:12058901
Martel, Anne-Claire; Zeggane, Sarah
Thermopile Detector Arrays for Space Science Applications
NASA Technical Reports Server (NTRS)
Thermopile detectors are widely used in uncooled applications where small numbers of detectors are required, particularly in low-cost commercial applications or applications requiring accurate radiometry. Arrays of thermopile detectors, however, have not been developed to the extent of uncooled bolometer and pyroelectric/ferroelectric arrays. Efforts at JPL seek to remedy this deficiency by developing high performance thin-film thermopile detectors in both linear and two-dimensional formats. The linear thermopile arrays are produced by bulk micromachining and wire bonded to separate CMOS readout electronic chips. Such arrays are currently being fabricated for the Mars Climate Sounder instrument, scheduled for launch in 2005. Progress is also described towards realizing a two-dimensional thermopile array built over CMOS readout circuitry in the substrate.
Foote, M. C.; Kenyon, M.; Krueger, T. R.; McCann, T. A.; Chacon, R.; Jones, E. W.; Dickie, M. R.; Schofield, J. T.; McCleese, D. J.; Gaalema, S.
A 4 ? charged-particle detector array for light-ion-induced nuclear fragmentation studies
NASA Astrophysics Data System (ADS)
Operating characteristics of the Indiana Silicon Sphere 4 ? detector array are outlined. The detector geometry is spherical, with 90 telescopes in the forward hemisphere and 72 at backward angles, covering a total solid angle of 74% of 4?. Each telescope consists of a simple gas-ion chamber, operated with C3F8 gas, followed by a 0.5 mm thick ion-implanted silicon detector and a 28 mm CsI(Tl) crystal, readout by a photodiode. Custom-built bias supplies and NIM preamp/shaper modules were used in conjunction with commercial CFD, TDC and ADC CAMAC units.
Kwiatkowski, K.; Alexander, A.; Bracken, D. S.; Brzychczyk, J.; Dorsett, J.; Ensman, R.; Renshaw Foxford, E.; Hamilton, T.; Komisarcik, K.; McDonald, K. N.; Morley, K. B.; Poehlman, J.; Powell, C.; Viola, V. E.; Yoder, N. R.; Ottarson, J.; Madden, N.
The Indiana silicon sphere 4 ? charged-particle detector array
NASA Astrophysics Data System (ADS)
A low threshold charged particle detector array for the study of fragmentation processes in light-ion-induced reactions has been constructed and successfully implemented at the IUCF and Saturne II accelerators. The array consists of 162-triple-element detector telescopes mounted in a spherical geometry and covering 74% of 4? in solid angle. Telescope elements are composed of (1) an axial-field gas ionization chamber operated with C3F8 gas; (2) a 0.5 mm thick passivated silicon detector, and (3) a 2.8 cm thick CsI(TI) scintillation crystal with photodiode readout. Discrete element identification is obtained for ejectiles up to Z ~ 16 over the dynamic range 0.7 <= E/A <= 95 MeV/nucleon. Isotopes are also distinguished for H, He, Li and Be ejectiles with 8 <~ E/A <~ 95 MeV. Custom-designed electronics are employed for bias supplies and linear signal processing. Data are acquired via a CAMAC/VME/Ethernet system.
Kwiatkowski, K.; Bracken, D. S.; Morley, K. B.; Brzychczyk, J.; Foxford, E. Renshaw; Komisarcik, K.; Viola, V. E.; Yoder, N. R.; Dorsett, J.; Poehlman, J.; Madden, N.; Ottarson, J.
Determination of nitroaromatic explosives and their degradation products in unsaturated-zone water samples by high-performance liquid chromatography with photodiode-array, mass spectrometric, and tandem mass spectrometric detection
Mass spectrometry and tandem mass spectrometry, coupled by a thermospray interface to a high-performance liguid chromatography system and equipped with a photodiode array detector, were used to determine the presence of nitroaromatic explosives and their degradation products in USA unsaturated-zone water samples. Using this approach, the lower limits of quantitation for explosives determined by mass spectrometry in this study typically ranged from 10 to 100 ng/l.
Gates, P.M.; Furlong, E.T.; Dorsey, T.F.; Burkhardt, M.R.
Large Ge Detector Array (GEANIE) at LANSCE
The large scale array GEANIE consists of 20 escape suppressed HPGe detectors and 10 low energy photon spectrometers (LEPS). This array is assembled on the 20 meter flight path 60R at the Weapons Neutron Research (WNR) facility in Los Alamos National Laboratory. The LANSCE spallation source produces high intensity neutrons between 0 and 400 MeV in energy. This unique facility
D. E. Archer; L. A. Bernstein; J. A. Becker; K. Hauschild; R. O. Nelson; S. Wender
High-resolution ionization detector and array of such detectors
A high-resolution ionization detector and an array of such detectors are described which utilize a reference pattern of conductive or semiconductive material to form interaction, pervious and measurement regions in an ionization substrate of, for example, CdZnTe material. The ionization detector is a room temperature semiconductor radiation detector. Various geometries of such a detector and an array of such detectors produce room temperature operated gamma ray spectrometers with relatively high resolution. For example, a 1 cm.sup.3 detector is capable of measuring .sup.137 Cs 662 keV gamma rays with room temperature energy resolution approaching 2% at FWHM. Two major types of such detectors include a parallel strip semiconductor Frisch grid detector and the geometrically weighted trapezoid prism semiconductor Frisch grid detector. The geometrically weighted detector records room temperature (24.degree. C.) energy resolutions of 2.68% FWHM for .sup.137 Cs 662 keV gamma rays and 2.45% FWHM for .sup.60 Co 1.332 MeV gamma rays. The detectors perform well without any electronic pulse rejection, correction or compensation techniques. The devices operate at room temperature with simple commercially available NIM bin electronics and do not require special preamplifiers or cooling stages for good spectroscopic results.
McGregor, Douglas S. (Ypsilanti, MI); Rojeski, Ronald A. (Pleasanton, CA)
Versatile silicon photodiode detector technology for scanning electron microscopy with high-efficiency sub-5 keV electron detection
A new silicon electron detector technology for Scanning Electron Microscopy, based on ultrashallow p+n boron-layer photodiodes, features nm-thin anodes enabling low-energy electron detection with record-high sensitivity down to 200 eV. Designs with segmented, closely-packed photodiodes and through-wafer apertures allow flexible configurations for optimal material and\\/or topographical contrasts. A high scanning speed is obtained by growing a well-controlled, lightly-doped, tens-of-microns-thick epi-layer
L. K. Nanver; G. van Veen; K. Kooijman; P. Vogelsang; T. L. M. Scholtes; W. de Boer; W. H. A. Wien; S. Milosavljevic?; C. T. H. Heerkens; I. Spee
Modeling Charge Collection in Detector Arrays
NASA Technical Reports Server (NTRS)
A detector array charge collection model has been developed for use as an engineering tool to aid in the design of optical sensor missions for operation in the space radiation environment. This model is an enhancement of the prototype array charge collection model that was developed for the Next Generation Space Telescope (NGST) program. The primary enhancements were accounting for drift-assisted diffusion by Monte Carlo modeling techniques and implementing the modeling approaches in a windows-based code. The modeling is concerned with integrated charge collection within discrete pixels in the focal plane array (FPA), with high fidelity spatial resolution. It is applicable to all detector geometries including monolithc charge coupled devices (CCDs), Active Pixel Sensors (APS) and hybrid FPA geometries based on a detector array bump-bonded to a readout integrated circuit (ROIC).
Hardage, Donna (Technical Monitor); Pickel, J. C.
Monolithic short wave infrared (SWIR) detector array
NASA Technical Reports Server (NTRS)
A monolithic self-scanned linear detector array was developed for remote sensing in the 1.1- 2.4-micron spectral region. A high-density IRCCD test chip was fabricated to verify new design approaches required for the detector array. The driving factors in the Schottky barrier IRCCD (Pdsub2Si) process development are the attainment of detector yield, uniformity, adequate quantum efficiency, and lowest possible dark current consistent with radiometric accuracy. A dual-band module was designed that consists of two linear detector arrays. The sensor architecture places the floating diffusion output structure in the middle of the chip, away from the butt edges. A focal plane package was conceptualized and includes a polycrystalline silicon substrate carrying a two-layer, thick-film interconnecting conductor pattern and five epoxy-mounted modules. A polycrystalline silicon cover encloses the modules and bond wires, and serves as a radiation and EMI shield, thermal conductor, and contamination seal.
Neutron detector characterization for SCINTIA array
SCINTIA is a new detector array of organic scintillators under development at the Inst. for Reference Materials and Measurements (IRMM). The present design of SCINTIA includes NE213, p-terphenyl and Li glass neutron detectors positioned in a spherical configuration around the target. The properties of a novel p-terphenyl neutron detector to be used with SCINTIA have been investigated using photon sources and neutrons from a time tagged {sup 252}Cf(sf) source. The results show that the p-terphenyl crystal has better energy resolution, increased proton light output and neutron efficiency when compared to a similar size NE213 equivalent neutron detector. (authors)
Matei, C.; Hambsch, F. J.; Oberstedt, S. [EC-JRC - Inst. for Reference Materials and Measurements, B-2440 Geel (Belgium)
Single-Photon-Sensitive HgCdTe Avalanche Photodiode Detector
NASA Technical Reports Server (NTRS)
The purpose of this program was to develop single-photon-sensitive short-wavelength infrared (SWIR) and mid-wavelength infrared (MWIR) avalanche photodiode (APD) receivers based on linear-mode HgCdTe APDs, for application by NASA in light detection and ranging (lidar) sensors. Linear-mode photon-counting APDs are desired for lidar because they have a shorter pixel dead time than Geiger APDs, and can detect sequential pulse returns from multiple objects that are closely spaced in range. Linear-mode APDs can also measure photon number, which Geiger APDs cannot, adding an extra dimension to lidar scene data for multi-photon returns. High-gain APDs with low multiplication noise are required for efficient linear-mode detection of single photons because of APD gain statistics -- a low-excess-noise APD will generate detectible current pulses from single photon input at a much higher rate of occurrence than will a noisy APD operated at the same average gain. MWIR and LWIR electron-avalanche HgCdTe APDs have been shown to operate in linear mode at high average avalanche gain (M > 1000) without excess multiplication noise (F = 1), and are therefore very good candidates for linear-mode photon counting. However, detectors fashioned from these narrow-bandgap alloys require aggressive cooling to control thermal dark current. Wider-bandgap SWIR HgCdTe APDs were investigated in this program as a strategy to reduce detector cooling requirements.
Huntington, Andrew
Photodiode radiation hardness, lyman-alpha emitting galaxies and photon detection in liquid argon neutrino detectors
NASA Astrophysics Data System (ADS)
My dissertation is comprised of three projects: 1) studies of Lyman-alpha Emitting galaxies (LAEs), 2) radiation hardness studies of InGaAs photodiodes (PDs), and 3) scintillation photon detection in liquid argon (LAr) neutrino detectors. I began work on the project that has now become WFIRST, developing a science case that would use WFIRST after launch for the observation of LAEs. The radiation hardness of PDs was as an effort to support the WFIRST calibration team. When WFIRST was significantly delayed, I joined an R&D effort that applied my skills to work on photon detection in LAr neutrino detectors. I report results on a broadband selection method developed to detect high equivalent width (EW) LAEs. Using photometry from the CFHT-Legacy Survey Deep 2 and 3 fields, I have spectroscopically confirmed 63 z=2.5-3.5 LAEs using the WIYN/Hydra spectrograph. Using UV continuum-fitting techniques I computed properties such as EWs, internal reddening and star formation rates. 62 of my LAEs show evidence to be normal dust-free LAEs. Second, I present an investigation into the effects of ionizing proton radiation on commercial off-the-shelf InGaAs PDs. I developed a monochromator-based test apparatus that utilized NIST-calibrated reference PDs. I tested the PDs for changes to their dark current, relative responsivity as a function of wavelength, and absolute responsivity. I irradiated the test PDs using 30, 52, and 98 MeV protons at the IU Cyclotron Facility. I found the InGaAs PDs showed increased dark current as the fluence increased with no evidence of broadband response degradation at the fluences expected at an L2 orbit and a 10-year mission lifetime. Finally, I detail my efforts on technology development of both optical detector technologies and waveshifting light guide construction for LAr vacuum UV scintillation light. Cryogenic neutrino detectors use photon detection for both accelerator based science and for SNe neutrino detection and proton decay. I have developed waveshifter doped cast acrylic light guides that convert scintillation light and guide the waveshifted light to SiPMs detectors.
Baptista, Brian
The SAPHIRA Near-Infrared Avalanche Photodiode Array: Telescope Deployments and Future Developments
NASA Astrophysics Data System (ADS)
We present our recent achievements of the Selex SAPHIRA APD arrays, which this year have seen deployment at three different telescopes, most notably demonstrating tip-tilt wavefront sensing in conjunction with the Palomar 1.5-m Telescope's Robo-AO system. A cooperative effort to provide enhanced speckle nulling capability to the SCExAO instrument on the Subaru telescope is also underway. We present the progress and development timeframe for the SAPHIRA and expected future applications, including targets and observational parameter space we expect the detectors to open to the astronomical community.
Atkinson, Dani Eleanor; Hall, Donald; Baranec, Christoph
Centroid tracking with area array detectors
NASA Technical Reports Server (NTRS)
A computer program (ALGEVAL) has been developed to simulate the position estimating behavior of a centroid estimator algorithm using data typical of optical point spread function data recorded by an area array detector. Typical results are shown of varying detector properties and optical point spread function types. The detector parameters currently available for study include read noise mean value, dark current mean value and spatial variation, charge transfer efficiency and point spread function location, saturation level, signal level and pixel size. The program is capable of calculating any order centroid using an array size from 2 x 2 to 15 x 15 pixels. The output of the program is either a performance map, histogram data or tabluar data. A number of further developments are recommended.
Glavich, T. A.
Terahertz detectors and focal plane arrays
NASA Astrophysics Data System (ADS)
Terahertz (THz) technology is one of emerging technologies that will change our life. A lot of attractive applications in security, medicine, biology, astronomy, and non-destructive materials testing have been demonstrated already. However, the realization of THz emitters and receivers is a challenge because the frequencies are too high for conventional electronics and the photon energies are too small for classical optics. As a result, THz radiation is resistant to the techniques commonly employed in these well established neighbouring bands. In the paper, issues associated with the development and exploitation of THz radiation detectors and focal plane arrays are discussed. Historical impressive progress in THz detector sensitivity in a period of more than half century is analyzed. More attention is put on the basic physical phenomena and the recent progress in both direct and heterodyne detectors. After short description of general classification of THz detectors, more details concern Schottky barrier diodes, pair braking detectors, hot electron mixers and field-effect transistor detectors, where links between THz devices and modern technologies such as micromachining are underlined. Also, the operational conditions of THz detectors and their upper performance limits are reviewed. Finally, recent advances in novel nanoelectronic materials and technologies are described. It is expected that applications of nanoscale materials and devices will open the door for further performance improvement in THz detectors.
Rogalski, A.; Sizov, F.
A new single nucleotide polymorphisms typing method and device by bioluminometric assay coupled with a photodiode array
NASA Astrophysics Data System (ADS)
Easy and inexpensive single nucleotide polymorphisms (SNPs) typing systems are required for the practice of genetic testing as well as genetic medicine. Most of the SNPs typing systems use laser-induced fluorescence detection coupled with fluorophore tagging on DNA, which are expensive. A new simple and inexpensive SNPs typing system is presented. It uses a bioluminometric assay coupled with modified primer extension reactions and an inexpensive photodiode array for the luminometric detection. The reagents consumed in the assay are also inexpensive. Although the system is very small, simple and inexpensive, it gives enough sensitivity for detecting target DNAs as small as 10 fmol, which is good enough for SNPs typing.
Kamahori, Masao; Harada, Kunio; Kambara, Hideki
Linear arrays of InGaAs/InP avalanche photodiodes for 1.0-1.7 micron
NASA Technical Reports Server (NTRS)
Separate absorption and multiplication InGaAs/InP avalanche photodiodes (SAM-APDs) with a floating guard ring structure that is well-suited to array applications have been successfully demonstrated. Individual APDs have breakdown voltages greater than 80 V, multiplications over 40 at 100 nA dark current, and uniform spatial gain profiles. Uniform I-V characteristics and gains have been measured over linear dimensions as large as 1.2 cm. Gains over 10 at low multiplied dark currents were measured on 21 consecutive devices at the wafer level.
Ackley, D. E.; Hladky, J.; Lange, M. J.; Mason, S.; Erickson, G.; Olsen, G. H.; Ban, V. S.; Forrest, S. R.; Staller, C.
Development of the ORRUBA Silicon Detector Array
High quality radioactive beams have recently made possible the measurement of (d,p) reactions on unstable nuclei in inverse kinematics, which can yield information on the development of single-neutron structure away from stability, and are of astrophysical interest due to the proximity to suggested r-process paths. The Oak Ridge Rutgers University Barrel Array (ORRUBA) is a new high solid-angular coverage array, composed of two rings of silicon detectors, optimized for measuring (d,p) reactions. A partial implementation has been used to measure (d,p) reactions on nuclei around the N = 82 shell closure.
Pain, S. D. [Rutgers University; Bardayan, Daniel W [ORNL; Blackmon, Jeff C [ORNL; Chae, K. Y. [University of Tennessee, Knoxville (UTK); Chipps, K. [Colorado School of Mines, Golden; Cizewski, J. A. [Rutgers University; Hatarik, Robert [Rutgers University; Johnson, M. S. [Oak Ridge Associated Universities (ORAU); Jones, K. L. [University of Tennessee, Knoxville (UTK); Kapler, R. [University of Tennessee, Knoxville (UTK); Kozub, R. L. [Tennessee Technological University; Matei, Catalin [Oak Ridge Associated Universities (ORAU); Moazen, Brian [University of Tennessee, Knoxville (UTK); Nesaraja, Caroline D [ORNL; O'Malley, Patrick [Rutgers University; Smith, Michael Scott [ORNL; Thomas, J. S. [Rutgers University
Design of a high sensitivity emitter-detector avalanche photodiode imager using very high transmittance, back-illuminated, silicon-on-sapphire
NASA Astrophysics Data System (ADS)
We present a detailed design study for a novel solid-state focal plane array of silicon avalanche photodiodes (APDs) using an advanced silicon-on-sapphire substrate incorporating an antireflective bilayer consisting of crystalline aluminum nitride (AlN) and amorphous, non-stoichiometric, silicon rich, silicon nitride (a-SiNX<1.33) between the silicon and sapphire. The substrate supports electrical and optical integration of a nearly 100% quantum efficiency, silicon APD capable of operating with wide dynamic range in dual linear or Geiger-mode, with a gallium nitride (GaN) laser diode in each pixel. The APD device and epitaxially grown GaN laser are fabricated within a crystallographically etched silicon mesa. The high resolution 27 ?m emitter-detector pixel design enables single photon sensitive, solid-state focal plane arrays (FPAs), with passive and active imaging capability in a single FPA. The square 27 ?m emitter-detector pixel achieves SNR>10 in active detection mode for Lambert surfaces at 20,000 m.
Stern, Alvin G.
Multi-channel photon counting three-dimensional imaging laser radar system using fiber array coupled Geiger-mode avalanche photodiode
NASA Astrophysics Data System (ADS)
Photon counting laser radar is the most sensitive and efficiency detection method of direct-detection laser radar. With the use of Geiger-mode avalanche photodiode (APD) or other single photon detectors, every laser photon could be sufficiently used for ranging and three-dimensional imaging. The average energy of received laser signal could be as low as a single photon, or even less than one. This feature of photon counting laser radar enables ranging under conditions of long range, low laser pulse energy, and multi-pixel detection, while receiver size, mass, power, and complexity of laser radar are reduced. In this paper, a latest multi-channel photon counting 3D imaging laser radar system using fiber array coupled Geiger-mode avalanche photodiode (APD) is introduced. Detection model based on Poisson statistics of a photon counting laser radar is discussed. A laser radar system, working under daylight condition with ultra-low signal level (less than single photon per pulse), has been designed and analyzed with the detection model and photon counting three-dimensional imaging theory. A passively Q-switched microchip laser is used to transmit short sub-nanosecond laser pulses at 532nm. The output laser is divided into 1�8 laser spots, which correspond to 8 Geiger-mode avalanche photodiodes coupled by a 1�8-pixel fiber array. A FPGA based time-to-digital converter (TDC), which is designed by delay line interpolation technology, is used for multi-hit signal acquisition. The algorithm of photon counting three-dimensional imaging is developed for signal photon events extraction and noise filter. Three-dimensional images under daylight conditions were acquired and analyzed. The results show that system could operate at strong solar background. The ranging accuracy of the system is 6.3cm (?) while received laser pulse signal level is only 0.04 photoelectrons on average. The advantages and feasibility of photon counting laser radar working at daylight have been demonstrated experimentally.
Shu, Rong; Huang, Genghua; Hou, Libing; He, Zhiping; Hu, Yihua
SQUID Multiplexers for Cryogenic Detector Arrays
NASA Technical Reports Server (NTRS)
SQUID multiplexers make it possible to build arrays of thousands of cryogenic detectors with a manageable number of readout channels. We are developing time-division SQUID multiplexers based on Nb trilayer SQUIDs to read arrays of superconducting transition-edge sensors. Our first-generation, 8-channel SQUID multiplexer was used in FIBRE, a one-dimensional TES array for submillimeter astronomy. Our second-generation 32-pixel multiplexer, based on an improved architecture, has been developed for instruments including Constellation-X, SCUBA-2, and solar x-ray astronomy missions. SCUBA-2, which is being developed for the James Clerk Maxwell Telescope, will have more than 10,000 pixels. We are now developing a third-generation architecture based on superconducting hot-electron switches. The use of SQUID multiplexers in instruments operating at above 2 K will also be discussed.
Irwin, Kent; Beall, James; Deiker, Steve; Doriese, Randy; Duncan, William; Hilton, Gene; Moseley, S. Harvey; Reintsema, Carl; Stahle, Caroline; Ullom, Joel; Vale, Leila
Development of high-transmittance back-illuminated silicon-on-sapphire substrates thinned below 25 micrometers and bonded to fused silica for high quantum efficiency and high resolution avalanche photodiode imaging arrays
NASA Astrophysics Data System (ADS)
There is a growing need in scientific and industrial applications for dual-mode, passive and active 2D and 3D LADAR imaging methods. To fill this need, solid-state, single photon sensitive silicon avalanche photodiode (APD) detector arrays offer high sensitivity and the possibility to operate with wide dynamic range in dual linear and Geiger-mode for passive and active imaging. To support the fabrication of large scale, high quantum efficiency and high resolution silicon avalanche photodiode arrays and other advanced solid-state optoelectronics, a novel, high transmittance, backilluminated silicon-on-sapphire substrate has been developed incorporating a single crystal, epitaxially grown aluminum nitride (AlN) antireflective layer between silicon and R-plane sapphire, that provides refractive index matching to improve the optical transmittance into silicon from sapphire. A one quarter wavelength magnesium fluoride antireflective layer deposited on the back-side of the sapphire improves optical transmittance from the ambient into the sapphire. The magnesium fluoride plane of the Si-(AlN)-sapphire substrate is bonded to a fused silica wafer that provides mechanical support, allowing the sapphire to be thinned below 25 micrometers to improve back-illuminated optical transmittance, while suppressing indirect optical crosstalk from APD emitted light undergoing reflections in the sapphire, to enable high quantum efficiency and high resolution detector arrays.
Stern, Alvin G.
Impact of a New Highly Sensitive HgCdTe Avalanche Photodiode Detector on Receiver Performance for the CO2 Sounder Lidar for the ASCENDS Mission
NASA Astrophysics Data System (ADS)
NASA Goddard Space Flight Center (GSFC) is currently developing a CO2 lidar as a candidate for the NASA's planned ASCENDS mission under the support of Earth Science Technology Office (ESTO) Instrument Incubator Program (IIP). As part of this work we have demonstrated new type of lower noise HgCdTe avalanche photodiode (APD) multi-element detector for the lidar receiver. This significantly improves the receiver sensitivity, lower the laser power, and reduce the receiver telescope size compared to InGaAs photomultiplier tubes (PMT) and APDs currently used. The HgCdTe APD arrays were designed and manufactured by DRS Technologies, Reconnaissance, Surveillance and Target Acquisition (RSTA) Division, which combines their mature HgCdTe APD detector in a hybrid package with a new custom cryogenic silicon preamplifier. The new detectors were specially designed for our airborne CO2 lidar and operate at ~ 77K inside a turn-key closed-cycle cooler. The detector has 80 ?m square pixels in a 4x4 array, and >70% fill factor and was custom designed to match the optics of our airborne and eventually space-based CO2 lidar. The initial results of evaluating the detector at NASA GSFC showed the HgCdTe APD assembly has a quantum efficiency of ~90% near 1550-nm, >500 APD gain, 8-10 MHz electrical bandwidth, and an average noise equivalent power of <1fW/Hz1/2. The detector also has a much wider linear dynamic range than PMTs, since it operates in a linear analog mode and has variable gain. Given the wide range of surface reflectivities this is important for ASCENDS. The new detector also greatly improves our CO2 lidar's receiver sensitivity. Calculations show it enables us to reduce the laser transmitter power by half for the space borne instrument while staying with a conventional reasonably sized (~1.2 m) diameter receiver telescope. We will show analysis and laboratory test results of the CO2 lidar performance using a receiver with this new detector. We are also funded by NASA ESTO to develop a high bandwidth HgCdTe APD under an Advanced Component Technology (ACT) program. DRS RSTA will use a new higher speed preamplifier and reduce the input capacitance to further reduce the noise and achieve linear mode photon counting performance.
Sun, X.; Abshire, J. B.
Two-dimensional detector arrays for gamma spectroscopy
We have developed a pixel detector hybrid called DANA-2 (Detector Array for Nuclear Applications). DANA-2 consists of a two-dimensional, monolithic Cadmium Zinc Telluride (CZT) detector array flip-chip bonded directly to a readout IC designed for high energy resolution. Both the detector and the IC have 16 � 16 pixels with a pitch of 0.5 mm � 0.5 mm; the detector
Martin Clajus; Victoria B. Cajipe; Tumay O. Tumer; Alexander Volkovskii
Radio Detector Array Simulation - A Full Simulation Chain for an Array of Antenna Detectors
Recently radio signals originating from extensive air showers have been observed at the Pierre Auger Observatory. In this note we present software to simulate the response of an array of antenna detectors and to reconstruct the radio signals. With this software it is possible to investigate design parameters of an antenna array and to visualize the radio data. We show comparisons between measurements of radio signals from air showers and simulated data which were generated with the REAS2 generator and then processed with the detector simulation and reconstruction software.
Fliescher, Stefan
Radio Detector Array Simulation - A Full Simulation Chain for an Array of Antenna Detectors
Recently radio signals originating from extensive air showers have been observed at the Pierre Auger Observatory. In this note we present software to simulate the response of an array of antenna detectors and to reconstruct the radio signals. With this software it is possible to investigate design parameters of an antenna array and to visualize the radio data. We show comparisons between measurements of radio signals from air showers and simulated data which were generated with the REAS2 generator and then processed with the detector simulation and reconstruction software.
Stefan Fliescher; for the Auger Collaboration
Test and evaluation of infrared detectors and arrays; Proceedings of the Meeting, Orlando, FL, Mar. 27-29, 1989
NASA Astrophysics Data System (ADS)
Papers on the testing and evaluation of IR detectors and arrays are presented, covering topics such as a short wavelength IR test system, pulse height analysis, the use of an expert system for IR detector testing, low-background IR focal plane testing, electron beam testing, high performance silicide Schottky photodiodes, the SDI organization focal plane test program, the absorption cross section of arsenic in silicon, and long wavelength IR hybrids. Other topics include low background radiometric detector measurements, an ultralow background dewar for IR detector characterization studies, a computer assisted mosaic array test station, a configurable detector array test station, automated detector material characterization capabilities, and a test system for mercury cadmium telluride photoconductor arrays. Additional topics include ionization dosimetry measurements inside a dewar for linac electron and californium-252 neutron environments, a radiation test facility using a variable-flux electron beam source, automated visual inspection of IR focal plane arrays, a titanium cryostat for low temperature radiation effects studies, a low dose rate gamma test facility, and the test and evaluation of stability in IR staring focal plane arrays after nonuniformity correction.
Hoke, Forney M.
The Trace Analysis of DEET in Water using an On-line Preconcentration Column and Liquid Chromatography with UV Photodiode Array Detection
A method for the detection of trace levels of N,N-diethyl-m-toluamide (DEET) in water is discussed. The method utilizes an on-line preconcentration column in series with high performance liquid chromatography (HPLC) and UV photodiode array detection. DEET, a common insect repel...
Microfluidic Biosensor Array with Integrated Poly(2,7-Carbazole)/Fullerene-Based Photodiodes for Rapid Multiplexed Detection of Pathogens
A multiplexed microfluidic biosensor made of poly(methylmethacrylate) (PMMA) was integrated into an array of organic blend heterojunction photodiodes (OPDs) for chemiluminescent detection of pathogens. Waterborne Escherichia coli O157:H7, Campylobacter jejuni and adenovirus were targeted in the PMMA chip, and detection of captured pathogens was conducted by poly(2,7-carbazole)/fullerene OPDs which showed a responsivity over 0.20 A/W at 425 nm. The limits of chemiluminescent detection were 5 � 105 cells/mL for E. coli, 1 � 105 cells/mL for C. jejuni, and 1 � 10?8 mg/mL for adenovirus. Parallel analysis for all three analytes in less than 35 min was demonstrated. Further recovery tests illustrated the potential of the integrated biosensor for detecting bacteria in real water samples. PMID:24287522
Pires, Nuno Miguel Matos; Dong, Tao
InAs/GaSb superlattice focal plane array infrared detectors: manufacturing aspects
NASA Astrophysics Data System (ADS)
InAs/GaSb type-II short-period superlattice (SL) photodiodes have been shown to be very promising for 2nd and 3rd generation thermal imaging systems with excellent detector performance. A multi-wafer molecular beam epitaxy (MBE) growth process on 3"-GaSb substrates, which allows simultaneous growth on five substrates with excellent homogeneity has been developed. A reliable III/V-process technology for badge processing of single-color and dual-color FPAs has been set up to facilitate fabrication of mono- and bi-spectral InAs/GaSb SL detector arrays for the mid-IR spectral range. Mono- and bispectral SL camera systems with different pitch and number of pixels have been fabricated. Those imaging systems show excellent electro-optical performance data with a noise equivalent temperature difference (NETD) around 10 mK.
Rutz, Frank; Rehm, Robert; Schmitz, Johannes; Fleissner, Joachim; Walther, Martin; Scheibner, Ralf; Ziegler, Johann
Silicon carbide photodiodes: future solar-blind EUV\\/soft x-ray detectors
The responsivity of a SiC photodiode was measured with synchrotron radiation in the deep UV and for the first time in the EUV and soft x-ray wavelength regions. A peak responsivity was 200 mA\\/W at 270 nm wavelength and 60 mA\\/w at 13 nm in the EUV. Extended measurements at shorter wavelengths demonstrated a responsivity up to 80 mA\\/W for
J. F. Seely; Benjawan Kjornrattanawanich; Raj Korde
Energy resolution of scintillation detectors readout with large area avalanche photodiodes and photomultipliers
The energy resolution of small NaI(Tl), CsI(Tl), BGO, GSO, YAP and LSO crystals has been studied using 16 mm diameter large area avalanche photodiodes (LAAPD) and a 52 mm diameter photomultiplier. The best result of 4.8% for 662 keV ?-rays from a 137Cs source was obtained with a 9 mm in diameter by 9 mm high CsI(Tl) scintillator coupled to
M. Moszynski; M. Kapusta; D. Wolski; M. Szawlowski; W. Klamra
Fabrication of pop-up detector arrays on Si wafers
High sensitivity is a basic requirement for a new generation of thermal detectors. To meet the requirement, close-packed, 2D silicon detector arrays have been developed in NASA Goddard Space Flight Center. The goal of the task is to fabricate detector arrays configured with thermal detectors such as IR bolometers and x-ray calorimeters to use in space flight missions. This paper
Mary J. Li; Christine A. Allen; Scott A. Gordon; Jonathan L. Kuhn; David B. Mott; Caroline K. Stahle; Liqin L. Wang
A validated high performance liquid chromatograph-photodiode array method for simultaneous determination of 10 bioactive components in compound hongdoushan capsule
Background: The compound Hongdoushan capsule (CHC) is widely known as compound herbal preparation and is often used to treat ovarian cancer and breast cancer, and to enhance the body immunity, etc., in clinical practice. Objective: To determine simultaneously 10 bioactive components from CHC, namely glycyrrhetinic acid, liquiritin, glycyrrhizin, baccatin III, 10-deacetylbaccatin III, cephalomannine, taxol, ginsenoside Rg1, ginsenoside Re, and ginsenoside Rb1. Materials and Methods: A high performance liquid chromatograph method coupled with photodiode array detector was developed and validated for the 1st time. Chromatographic analysis was performed on a SHIMADZU C18 by utilizing a gradient elution program. The mobile phase was acetonitrile (A)-water (B) at a flow rate of 0.8 mL/min. Results: The calibration curve was linear over the investigated concentration ranges with the values of r2 higher than 0.9993 for all the 10 bioactive components. The average recovery rates range from 98.4% to 100.5% with relative standard deviations ?2.9%. The developed method was successfully applied to analyze 10 compounds in six CHC samples from different batches. In addition, the herbal sources of 32 chromatographic peaks were identified through comparative studying on chromatograms of standard, the respective extracts of Hongdoushan, RenShen, GanCao, and CHC. Conclusion: All the results imply that the accurate and reproducible method developed has high separation rate and enables the determination of 10 bioactive components in a single run for the quality control of CHC. PMID:24696551
Zhu, Liancai; Yang, Xian; Tan, Jun; Wang, Bochu; Zhang, Xue
Achieving a Linear Dose Rate Response in Pulse-Mode Silicon Photodiode Scintillation Detectors Over a Wide Range of Excitations
NASA Astrophysics Data System (ADS)
We are developing a new dose calibrator for nuclear pharmacies that can measure radioactivity in a vial or syringe without handling it directly or removing it from its transport shield �pig�. The calibrator's detector comprises twin opposing scintillating crystals coupled to Si photodiodes and current-amplifying trans-resistance amplifiers. Such a scheme is inherently linear with respect to dose rate over a wide range of radiation intensities, but accuracy at low activity levels may be impaired, beyond the effects of meager photon statistics, by baseline fluctuation and drift inevitably present in high-gain, current-mode photodiode amplifiers. The work described here is motivated by our desire to enhance accuracy at low excitations while maintaining linearity at high excitations. Thus, we are also evaluating a novel �pulse-mode� analog signal processing scheme that employs a linear threshold discriminator to virtually eliminate baseline fluctuation and drift. We will show the results of a side-by-side comparison of current-mode versus pulse-mode signal processing schemes, including perturbing factors affecting linearity and accuracy at very low and very high excitations. Bench testing over a wide range of excitations is done using a Poisson random pulse generator plus an LED light source to simulate excitations up to �106 detected counts per second without the need to handle and store large amounts of radioactive material.
Carroll, Lewis
Organic non-volatile resistive photo-switches for flexible image detector arrays.
A unique implementation of an organic image detector using resistive photo-switchable pixels is presented. This resistive photo-switch comprises the vertical integration of an organic photodiode and an organic resistive switching memory element. The photodiodes act as a photosensitive element while the resistive switching elements simultaneously store the detected light information. PMID:25534514
Nau, Sebastian; Wolf, Christoph; Sax, Stefan; List-Kratochvil, Emil J W
Room-temperature InGaAs detector arrays for 1.0 - 1.7 microns spectroscopy
NASA Technical Reports Server (NTRS)
Linear arrays of 256 element InGaAs detectors with 100 x 30 micron pixels were mounted in multiplexer packages and tested in an optical multichannel analyzer (OMA). Typical performance characteristics include dark current (-5V) of 400 picoamps and responsivities of 0.75 A/W (1.3 microns) and 0.14 A/W (0.85 microns). The 256 element exhibited a mean room-temperature dark current of under 400 picoamps when mounted in the OMA and a dynamic range over 11 bits (2000:1). Future applications, including room-temperature detector arrays for 2.5 microns and avalanche photodiode arrays for 1.0-1.7 microns, are discussed.
Olsen, G. H.; Joshi, A. M.; Mykietyn, E.; Colosi, J.; Woodruff, K. M.
Detector arrays for low-background space infrared astronomy
NASA Technical Reports Server (NTRS)
The status of development and characterization tests of integrated infrared detector array technology for astronomy applications is described. The devices under development include intrinsic, extrinsic silicon, and extrinsic germanium detectors, with hybrid silicon multiplexers. Laboratary test results and successful astronomy imagery have established the usefulness of integrated arrays in low-background astronomy applications.
Mccreight, C. R.; Mckelvey, M. E.; Goebel, J. H.; Anderson, G. M.; Lee, J. H.
Position sensitivity of MAMA detectors. [Multi-Anode Microchannel Array
NASA Technical Reports Server (NTRS)
The results of laboratory and telescopic measurements of the position sensitivity of a visible MAMA detector utilizing a 'coarse-fine' array are presented. The photometric accuracy of this detector was determined under point source illumination. It was found that computed centroid positions are accurate across the entire array to within 0.04 pixels.
Morgan, J. S.; Slater, D. S.; Timothy, J. G.; Jenkins, E. B.
The Impact of Array Detectors on Raman Spectroscopy
ERIC Educational Resources Information Center
The impact of array detectors in the field of Raman spectroscopy and all low-light-level spectroscopic techniques is examined. The high sensitivity of array detectors has allowed Raman spectroscopy to be used to detect compounds at part per million concentrations and to perform Raman analyses at advantageous wavelengths.
Denson, Stephen C.; Pommier, Carolyn J. S.; Denton, M. Bonner
Detector arrays for low-background space infrared astronomy
NASA Technical Reports Server (NTRS)
The status of development and characterization tests of integrated infrared detector array technology for astronomy applications is described. The devices under development include intrinsic, extrinsic silicon, and extrinsic germanium detectors, with hybrid silicon multiplexers. Laboratory test results and successful astronomy imagery have established the usefulness of integrated arrays in low-background astronomy applications.
Mccreight, C. R.; Mckelvey, M. E.; Goebel, J. H.; Anderson, G. M.; Lee, J. H.
The 1.06 micrometer avalanche photodiode detectors with integrated circuit preamplifiers
NASA Technical Reports Server (NTRS)
The development of a complete solid state 1.06 micron optical receiver which can be used in optical communications at data rates approaching 1.5 Gb/s, or in other applications requiring sensitive, short-pulse detection, is reported. This work entailed both the development of a new type of heterojunction 3-5 semiconductor alloy avalanche photodiode and an extremely charge-sensitive wideband low-noise preamp design making use of GaAs Schottky barrier-gate field effect transistors.
Eden, R. C.
Triangular-barrier quantum rod photodiodes: Their fabrication and detector characteristics
We have fabricated a GaAs-based triangular-barrier photodiode, in which self-assembled InGaAs quantum rods (Q-rods) are embedded in its barrier region. Transport study at 100?K has shown that electrons start to flow mainly through Q-rods when a bias is set above a threshold. Upon illumination, photo-generated holes are found to accumulate in the middle portion of Q-rods and efficiently lower the local barrier height, yielding the responsivity as high as 10{sup 5}?A/W at the incident light of 1 fW.
Ohmori, M.; Kobayashi, Y.; Vitushinskiy, P.; Nakamura, S.; Kojima, T.; Sakaki, H. [Toyota Technological Institute, 2-12-1 Hisakata, Tempaku-ku, Nagoya 468-0034 (Japan)
Design and testing of an active quenching circuit for an avalanche photodiode photon detector
NASA Technical Reports Server (NTRS)
The photon-detection capabilities of avalanche photodiodes (APDs) operating above their theoretical breakdown voltages are described, with particular attention given to the needs and methods of quenching an avalanche once breakdown has occurred. A brief background on the motives of and previous work with this mode of operation is presented. Finally, a description of the design and testing of an active quenching circuit is given. Although the active quenching circuit did not perform as expected, knowledge was gained as to the signal amplitudes necessary for quenching and the need for a better model for the above-breakdown circuit characteristics of the Geiger-mode APD.
Arbel, D.; Schwartz, J. A.
Multiwavelength infrared focal plane array detector
NASA Technical Reports Server (NTRS)
A multiwavelength focal plane array infrared detector is included on a common substrate having formed on its top face a plurality of In.sub.x Ga.sub.1-x As (x.ltoreq.0.53) absorption layers, between each pair of which a plurality of InAs.sub.y P.sub.1-y (y<1) buffer layers are formed having substantially increasing lattice parameters, respectively, relative to said substrate, for preventing lattice mismatch dislocations from propagating through successive ones of the absorption layers of decreasing bandgap relative to said substrate, whereby a plurality of detectors for detecting different wavelengths of light for a given pixel are provided by removing material above given areas of successive ones of the absorption layers, which areas are doped to form a pn junction with the surrounding unexposed portions of associated absorption layers, respectively, with metal contacts being formed on a portion of each of the exposed areas, and on the bottom of the substrate for facilitating electrical connections thereto.
Forrest, Stephen R. (Inventor); Olsen, Gregory H. (Inventor); Kim, Dong-Su (Inventor); Lange, Michael J. (Inventor)
Performance characteristics of multi-anode microchannel array detector systems
NASA Technical Reports Server (NTRS)
The multi-anode microchannel arrays (MAMAs) are state-of-the-art, pulse-counting, photoelectric array detectors designed specifically for use in space astrophysics instruments. The present paper provides a description of recent progress related to the development of ultraviolet and visible-light versions of the MAMA detectors, taking into account a comparison of the operating characteristics of these devices with those of photoconductive array detectors, such as the CCDs. Attention is given to MAMA detector system design parameters, the operating characteristics of MAMAs and CCDs, MAMA performance characteristics, and future developments.
Timothy, J. G.
1-D array of perforated diode neutron detectors
Performance of a 4cm long 64-pixel perforated diode neutron detector array is compared with an identical array of thin-film coated diodes. The perforated neutron detector design has been adapted to a 1-D pixel array capable of 120?m spatial resolution and counting efficiency greater than 12%. Deep vertical trenches filled with 6LiF provide outstanding improvement in efficiency over thin-film coated diode
Walter J. McNeil; Steven L. Bellinger; Troy C. Unruh; Chris M. Henderson; Phil Ugorowski; Bryce Morris-Lee; Russell D. Taylor; Douglas S. McGregor
1-D array of perforated diode neutron detectors
Performance of a 4 cm long 64-pixel perforated diode neutron detector array is compared with an identical array of thin-film coated diodes. The perforated neutron detector design has been adapted to a 1-D pixel array capable of 120 mum spatial resolution and counting efficiency greater than 12%. Deep vertical trenches filled with 6LiF provide outstanding improvement in efficiency over thin-film
Walter J. McNeil; Steven L. Bellinger; Troy C. Unruh; Chris M. Henderson; Phil Ugorowski; Bryce Morris-Lee; Russell D. Taylor; Douglas S. McGregor
Comparison of magnetic resonance imaging-compatible optical detectors for in-magnet tissue spectroscopy: photodiodes versus silicon photomultipliers
NASA Astrophysics Data System (ADS)
Tissue spectroscopy inside the magnetic resonance imaging (MRI) system adds a significant value by measuring fast vascular hemoglobin responses or completing spectroscopic identification of diagnostically relevant molecules. Advances in this type of spectroscopy instrumentation have largely focused on fiber coupling into and out of the MRI; however, nonmagnetic detectors can now be placed inside the scanner with signal amplification performed remotely to the high field environment for optimized light detection. In this study, the two possible detector options, such as silicon photodiodes (PD) and silicon photomultipliers (SiPM), were systematically examined for dynamic range and wavelength performance. Results show that PDs offer 10 (160 dB) dynamic range with sensitivity down to 1 pW, whereas SiPMs have 10 (140 dB) dynamic range and sensitivity down to 10 pW. A second major difference is the spectral sensitivity of the two detectors. Here, wavelengths in the 940 nm range are efficiently captured by PDs (but not SiPMs), likely making them the superior choice for broadband spectroscopy guided by MRI.
El-Ghussein, Fadi; Jiang, Shudong; Pogue, Brian W.; Paulsen, Keith D.
Investigation of depth-of-interaction by pulse shape discrimination in multicrystal detectors read out by avalanche photodiodes
The measurement of depth of interaction (DOI) within detectors is necessary to improve resolution uniformity across the FOV of small diameter PET scanners. DOI encoding by pulse shape discrimination (PSD) has definite advantages as it requires only one readout per pixel and it allows DOI measurement of photoelectric and Compton events. The PSD time characteristics of various scintillators were studied with avalanche photodiodes (APD) and the identification capability was tested in multi-crystal assemblies with up to four scintillators. In the PSD time spectrum of an APD-GSO/LSO/BGO/CsI(Tl) assembly, four distinct time peaks at 45, 26, 88 and 150 ns relative to a fast test pulse, having resolution of 10.6, 5.2, 20 and 27 ns, can be easily separated. Whereas the number and position of scintillators in the multi-crystal assemblies affect detector performance, the ability to identify crystals is not compromised. Compton events have a significant effect on PSD accuracy, suggesting that photopeak energy gating should be used for better crystal identification. However, more sophisticated PSD techniques using parametric time-energy histograms can also improve crystal identification in cases where PSD time or energy discrimination alone is inadequate. These results confirm the feasibility of PSD DOI encoding with APD-based detectors for PET.
Saoudi, A.; Pepin, C.M.; Dion, F.; Bentourkia, M.; Lecomte, R. [ Univ. de Sherbrooke, Quebec (Canada). Dept. of Nuclear Medicine and Radiobiology] [Univ. de Sherbrooke, Quebec (Canada). Dept. of Nuclear Medicine and Radiobiology; Andreaco, M.; Casey, M.; Nutt, R. [CTI PET Systems Inc., Knoxville, TN (United States)] [CTI PET Systems Inc., Knoxville, TN (United States); Dautet, H. [EG and G Optoelectronics, Vaudreuil, Quebec (Canada)] [EG and G Optoelectronics, Vaudreuil, Quebec (Canada)
Multianode microchannel array detectors for Space Shuttle imaging applications
NASA Technical Reports Server (NTRS)
The Multi-Anode Microchannel Arrays (MAMAs) are a family of photoelectric, photoncounting array detectors that have been developed and qualified specifically for use in space. MAMA detectors with formats as large as 256 x 1024 pixels are now in use or under construction for a variety of imaging and tracking applications. These photo-emissive detectors can be operated in a windowless configuration at extreme ultraviolet and soft X-ray wavelengths or in a sealed configuration at ultraviolet and visible wavelengths. The construction and modes-of-operation of the MAMA detectors are briefly described and the scientific objectives of a number of sounding rocket and Space Shuttle instruments utilizing these detectors are outlined. Performance characteristics of the MAMA detectors that are of fundamental importance for operation in the Space Shuttle environment are described and compared with those of the photo-conductive array detectors such as the CCDs and CIDs.
Timothy, J. G.; Bybee, R. L.
Enhanced photoresponse of conformal TiO{sub 2}/Ag nanorod array-based Schottky photodiodes fabricated via successive glancing angle and atomic layer deposition
In this study, the authors demonstrate a proof of concept nanostructured photodiode fabrication method via successive glancing angle deposition (GLAD) and atomic layer deposition (ALD). The fabricated metal-semiconductor nanorod (NR) arrays offer enhanced photoresponse compared to conventional planar thin-film counterparts. Silver (Ag) metallic NR arrays were deposited on Ag-film/Si templates by utilizing GLAD. Subsequently, titanium dioxide (TiO{sub 2}) was deposited conformally on Ag NRs via ALD. Scanning electron microscopy studies confirmed the successful formation of vertically aligned Ag NRs deposited via GLAD and conformal deposition of TiO{sub 2} on Ag NRs via ALD. Following the growth of TiO{sub 2} on Ag NRs, aluminum metallic top contacts were formed to complete the fabrication of NR-based Schottky photodiodes. Nanostructured devices exhibited a photo response enhancement factor of 1.49?�?10{sup 2} under a reverse bias of 3 V.
Haider, Ali; Biyikli, Necmi, E-mail: firstname.lastname@example.com [National Nanotechnology Research Center (UNAM), Bilkent University, Bilkent, Ankara 06800, Turkey and Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, Ankara 06800 (Turkey); Cansizoglu, Hilal; Cansizoglu, Mehmet Fatih; Karabacak, Tansel [Department of Physics and Astronomy, University of Arkansas at Little Rock, Little Rock, Arkansas 72204 (United States); Okyay, Ali Kemal [National Nanotechnology Research Center (UNAM), Bilkent University, Bilkent, Ankara 06800 (Turkey); Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, Ankara 06800 (Turkey); Department of Electrical and Electronics Engineering, Bilkent University, Bilkent, Ankara 06800 (Turkey)
Results from the Puebla extensive air shower detector array
NASA Astrophysics Data System (ADS)
We describe the design and operation of the first stage of the EAS-UAP extensive air shower array, as a detector of very high energy cosmic rays ( Eo > 10 14eV). The array is located at the Campus of Puebla University and consists of 18 liquid scintillator detectors, with an active surface of 1 m2 each and a detector spacing of 20 m in a square grid. In this report we discuss the stability and the calibration of the detector array, as derived from the 10 detectors in operation in the first stage. The main characteristics of the array allow us also to use it as an educational and training facility. First distributions of the arrival direction and the lateral shower srpead are also given.
Salazar, H.; Martinez, O.; Moreno, E.; Cotzomi, J.; Villase�or, L.; Saavedrac, O.
Simultaneous determination of vitamins C, E and ?-carotene in human plasma by high-performance liquid chromatography with photodiode-array detection
Purpose: To develop a high-performance liq- uid chromatography (HPLC) method with photodiode- array ultraviolet detection for the simultaneous determi- nation of vitamin C, vitamin E and ?-carotene. Meth- ods: Following liquid-phase extraction from the human plasma samples, these three vitamins were successfully separated on the LiChrospher 100 RP-18 column (125 � 4 mm I.D.; particle size, 5 �m) at a
Bin Zhao; Su-Yin Tham; Jia Lu; Mui Hoon Lai; Lionel K. H. Lee; Shabbir M Moochhala
Use of high-performance liquid chromatography with photodiode-array UV detection for the creation of a 600-compound library application to forensic toxicology
A high-performance liquid chromatographic method is described with photodiode array detection for systematic toxicological analysis in human blood and urine. After a single step liquid-liquid extraction using Toxi-Tube A, drugs are analyzed with a multi step gradient (phosphate pH 3.8-acetonitrile) on a Symmetry C8 5-?m column (250 mm � 4.6 mm I.D.) (Waters), operated at 30�C. The flow-rate is varied
Yvan Gaillard; Gilbert P�pin
Analysis of several phenolic compounds with potential antioxidant properties in grape extracts and wines by high-performance liquid chromatography�photodiode array detection without sample preparation
A RP-HPLC method that allows the separation of several types of phenolic compounds present in grapes and wines by direct injection of samples, using a binary gradient with solvents free of salts and photodiode array detection is described. Results show that more than 15 different phenolic molecules with antioxidant properties (flavan-3-ols, anthocyanins, cinnamic acid derivatives, flavonol derivatives and trans-resveratrol) may
Eugenio Revilla; Jos�-Mar??a Ryan
Quantitative analysis of flavonols, flavones, and flavanones in fruits, vegetables and beverages by high-performance liquid chromatography with photo-diode array and mass spectrometric detection
A high-performance liquid chromatographic (HPLC) separation method with photo-diode array (PDA) and mass spectrometric (MS) detection was developed to determine and quantify flavonols, flavones, and flavanones in fruits, vegetables and beverages. The compounds were analysed as aglycones, obtained after acid hydrolysis of freeze-dried food material. Identification was based on retention time, UV and mass spectra by comparison with commercial standards,
Ulla Justesen; Pia Knuthsen; Torben Leth
Automated on-line liquid chromatography�photodiode array�mass spectrometry method with dilution line for the determination of bisphenol A and 4-octylphenol in serum
A novel on-line liquid chromatography�photodiode array detection�mass spectrometry (LC�DAD�MS) system was established with restricted-access media (RAM) pre-column and dilution line combined with a column-switching valve. The serum samples were injected directly onto pre-column under diluted condition by dilution line. After elution of proteins in the serum, the analytes were backflushed onto an ODS analytical column using a six-port column-switching device.
Min Liu; Yuki Hashi; Fengyun Pan; Jianguo Yao; Guanqun Song; Jin-Ming Lin
High-performance liquid chromatographic analysis of Black Cohosh ( Cimicifuga racemosa) constituents with in-line evaporative light scattering and photodiode array detection
A validated and reproducible high-performance liquid chromatography (HPLC) method with in-line evaporative light scattering and photodiode array detection was developed for the analysis of major constituents in Black Cohosh (Cimicifuga racemosa L.). The method is based on the baseline chromatographic separation of 18 compounds reported to be present in Black Cohosh on a C-18 column (5?m, 4.6mm�250mm) with water (0.05%
Wenkui Li; Shaonong Chen; Daniel Fabricant; Cindy K Angerhofer; Harry H. S Fong; Norman R Farnsworth; John F Fitzloff
Use of a linear photodiode array in order to estimate in real time the contribution of the lower atmospheric layers in astronomical-image degradation
One-dimensional autocorrelation functions for the angle-of-arrival fluctuations are estimated in real time using a linear photodiode array and a numerical correlator. The results are found to be in agreement with the inertial model of turbulence for spatial shifts up to 25 cm in daytime conditions and up to 1.10 m in nighttime conditions. The Fried's seeing parameter r0 and the
M. Azouit; J. Borgnino; J. Vernin
Ultrasound-assisted extraction of phenolic compounds from strawberries prior to liquid chromatographic separation and photodiode array ultraviolet detection.
Ultrasound-assisted extraction was used for the determination of phenolic compounds present in strawberries. The optimization study of the extraction was carried out using spiked samples (100 mg/kg). The sample immersed in an aqueous solution containing hydrochloric acid (0.4 M) was sonicated for 2 min (duty cycle 0.2 s, output amplitude 20% of the nominal amplitude of the converter, applied power 100 W with the probe placed 1cm from the bottom of the water bath and 5 cm from the walls of the precipitate glass). Subsequent separation was carried out by liquid chromatography (LC) with photodiode array UV detection. Calibration curves using the standard addition in green strawberries typically gave linear dynamic ranges of 2-300 mg/l for all analytes; R(2) values exceeded 0.996 in all cases. The method was applied to two types of strawberries to demonstrate the applicability of the proposed method, which is much faster and produces less analyte degradation than methods as solid-liquid, subcritical water and microwave-assisted extraction. PMID:16203008
Herrera, M C; de Castro, M D Luque
Hybrid photomultiplier tube and photodiode parallel detection array for wideband optical spectroscopy of the breast guided by magnetic resonance imaging
Abstract. A new optical parallel detection system of hybrid frequency and continuous-wave domains was developed to improve the data quality and accuracy in recovery of all breast optical properties. This new system was deployed in a previously existing system for magnetic resonance imaging (MRI)-guided spectroscopy, and allows incorporation of additional near-infrared wavelengths beyond 850�nm, with interlaced channels of photomultiplier tubes (PMTs) and silicon photodiodes (PDs). The acquisition time for obtaining frequency-domain data at six wavelengths (660, 735, 785, 808, 826, and 849�nm) and continuous-wave data at three wavelengths (903, 912, and 948�nm) is 12�min. The dynamic ranges of the detected signal are 105 and 106 for PMT and PD detectors, respectively. Compared to the previous detection system, the SNR ratio of frequency-domain detection was improved by nearly 103 through the addition of an RF amplifier and the utilization of programmable gain. The current system is being utilized in a clinical trial imaging suspected breast cancer tumors as detected by contrast MRI scans. PMID:23979460
El-Ghussein, Fadi; Mastanduno, Michael A.; Jiang, Shudong; Pogue, Brian W.; Paulsen, Keith D.
Hybrid photomultiplier tube and photodiode parallel detection array for wideband optical spectroscopy of the breast guided by magnetic resonance imaging
NASA Astrophysics Data System (ADS)
A new optical parallel detection system of hybrid frequency and continuous-wave domains was developed to improve the data quality and accuracy in recovery of all breast optical properties. This new system was deployed in a previously existing system for magnetic resonance imaging (MRI)-guided spectroscopy, and allows incorporation of additional near-infrared wavelengths beyond 850 nm, with interlaced channels of photomultiplier tubes (PMTs) and silicon photodiodes (PDs). The acquisition time for obtaining frequency-domain data at six wavelengths (660, 735, 785, 808, 826, and 849 nm) and continuous-wave data at three wavelengths (903, 912, and 948 nm) is 12 min. The dynamic ranges of the detected signal are 105 and 106 for PMT and PD detectors, respectively. Compared to the previous detection system, the SNR ratio of frequency-domain detection was improved by nearly 103 through the addition of an RF amplifier and the utilization of programmable gain. The current system is being utilized in a clinical trial imaging suspected breast cancer tumors as detected by contrast MRI scans.
El-Ghussein, Fadi; Mastanduno, Michael A.; Jiang, Shudong; Pogue, Brian W.; Paulsen, Keith D.
Development of 58 x 62 Si:Sb detector arrays
NASA Technical Reports Server (NTRS)
The fabrication of antimony doped silicon (Si:Sb) detector arrays are described for use in 30 micron infrared imaging applications. The operation of the multiplexer readout circuit which will be used for this application is also described.
Worley, S.; Gaalema, S.
Achiral and chiral high-performance liquid chromatographic determination of flubendazole and its metabolites in biomatrices using UV photodiode-array and mass spectrometric detection.
Flubendazole, methyl ester of [5-(4-fluorobenzoyl)-1H-benzimidazol-2-yl]carbamic acid, belongs to the group of benzimidazole anthelmintics, which are widely used in veterinary and human medicine. The phase I flubendazole biotransformation includes a hydrolysis of the carbamoyl methyl moiety accompanied by a decarboxylation (hydrolysed flubendazole) and a carbonyl reduction of flubendazole (reduced flubendazole). Flubendazole is a prochiral drug, hence a racemic mixture is formed during non-stereoselective reductions at the carbonyl group. Two bioanalytical HPLC methods were developed and validated for the determination of flubendazole and its metabolites in pig and pheasant hepatic microsomal and cytosolic fractions. Analytes were extracted from biomatrices into tert-butylmethyl ether. The first, achiral method employed a 250 mm x 4 mm column with octylsilyl silica gel (5 microm) and an isocratic mobile phase acetonitrile-0.025 M KH(2)PO(4) buffer pH 3 (28:72, v/v). Albendazole was used as an internal standard. The whole analysis lasted 27 min at a flow rate of 1 ml/min. The second, chiral HPLC method, was performed on a Chiralcel OD-R 250 mm x 4.6 mm column with a mobile phase acetonitrile-1 M NaClO(4) (4:6, v/v). This method enabled the separation of both reduced flubendazole enantiomers. The enantiomer excess was evaluated. The column effluent was monitored using a photodiode-array detector (scan or single wavelength at lambda=246 nm). Each of the analytes under study had characteristic UV spectrum, in addition, their chemical structures were confirmed by high-performance liquid chromatography-mass spectrometry (HPLC-MS) experiments. Stereospecificity in the enzymatic carbonyl reduction of flubendazole was observed. While synthetic racemic mixture of reduced flubendazole was separated to equimolar amounts of both enantiomers, practically only one enantiomer was detected in the extracts from all incubates. PMID:17258754
Nobilis, Milan; Jira, Thomas; L�sa, Miroslav; Holcapek, Michal; Szot�kov�, Barbora; Lamka, Jir�; Sk�lov�, Lenka
Determination of HT-2 and T-2 toxins in oats and wheat by ultra-performance liquid chromatography with photodiode array detection.
European intake estimates indicate that the presence of HT-2 and T-2 toxins in cereals, mainly in oats, can be of concern for human health. Therefore, the development of sensitive, rapid and reliable methods for determining these mycotoxins in cereals, in particular oats, has high priority. A rapid ultra-performance liquid chromatographic (UPLC) method has been developed for the simultaneous determination of HT-2 and T-2 toxins in oats and wheat at ?g kg(-1) level. Ground samples were extracted with methanol/water (90:10, v/v) and the diluted extracts were cleaned up through immunoaffinity columns. HT-2 and T-2 toxins were separated and quantified by UPLC with photodiode array (PDA) detector (?=202 nm) in less than 5 min. Mean recoveries from blank oats samples spiked with HT-2 and T-2 toxins at levels of 50-1000 ?g kg(-1) ranged from 87 to 96%, with relative standard deviations (RSDs) lower than 7%; mean recoveries from wheat spiked with HT-2 and T-2 toxins at levels of 25-100 ?g kg(-1) ranged from 91 to 103%, with RSDs lower than 5%. The limit of detection of the method was 8 ?g kg(-1) for both toxins (signal-to-noise ratio 3:1). The method was successfully applied to the analysis of HT-2 and T-2 toxins in naturally contaminated oats and wheat samples. A good correlation was found by comparative analysis of naturally contaminated samples of oats (r=0.9985) and wheat (r=0.9058) using the proposed method or a reliable HPLC method with fluorescence detection after pre-column derivatization with 1-anthroylnitrile. PMID:22284485
Pascale, Michelangelo; Panzarini, Giuseppe; Visconti, Angelo
Muon detector of the Kover-2 array
NASA Astrophysics Data System (ADS)
The general design and principal features of Kover-2, a large-area EAS array now under construction in the vicinity of the Kover EAS array in the Baksan Valley in North Caucasus, are described. The Kover 2 array, which is to be completed in 1993, will have a total area of 700 sq m and a threshold muon energy of 1 GeV. The performance of the array has been successfully demonstrated using a functional mockup.
Alekseev, E. N.; Alekseenko, V. V.; Alekseenko, N. A.; Voevodskij, A. V.; Dzhappuev, D. D.; Konovalov, Yu. N.; Konoplya, M. M.; Kudzhaev, A. U.; Marchuk, D. L.; Malovichko, Yu. V.
Particle Identification in the NIMROD-ISiS Detector Array
Interest in the influence of the neutron-to-proton (N/Z) ratio on multifragmenting nuclei has demanded an improvement in the capabilities of multi-detector arrays as well as the companion analysis methods. The particle identification method used in the NIMROD-ISiS 4 $\\pi$ array is described. Performance of the detectors and the analysis method are presented for the reaction of 86Kr+64Ni at 35MeV/u.
S. Wuenschel; K. Hagel; L. W. May; R. Wada; S. J. Yennello
Particle Identification in the NIMROD-ISiS Detector Array
Interest in the influence of the neutron-to-proton (N/Z) ratio on multifragmenting nuclei has demanded an improvement in the capabilities of multi-detector arrays as well as the companion analysis methods. The particle identification method used in the NIMROD-ISiS 4{pi} array is described. Performance of the detectors and the analysis method are presented for the reaction of {sup 86}Kr+{sup 64}Ni at 35 MeV/u.
Wuenschel, S.; Hagel, K.; May, L. W.; Wada, R.; Yennello, S. J. [Texas A and M University Cyclotron Institute College Station TX 77843 (United States)
A Research on CdZnTe Array Detector
NASA Astrophysics Data System (ADS)
The CdZnTe array detector is a new type of semiconductor detector, and it has been developing rapidly in recent years. It has some characteristics of high spatial resolution, high energy resolution, and it can work at room temperature. This article describes the physical characteristics and the working principle of the CdZnTe detector. It also introduces the production process of the CdZnTe array detector, including the pretreatment of the chips, passivation, ohmic electrode production, array template selection, and array package process selection (micro-interconnect). For evaluating the performance of the detector, the authors produced a 4 pixel � 4 pixel CdZnTe array and an 8 pixel � 8 pixel CdZnTe array (The thicknesses are 5 mm and 2 mm, respectively.The pixel size is 2 mm � 2 mm. The gaps are 0.15 mm and 0.2 mm, respectively.) with cooperation partner successfully. A multi-channel electronic readout system based on the ASIC (Application Specific Integrated Circuit) chip is used for the charge measurement of the 4 pixel � 4 pixel array of CdZnTe. The 16-pixel spectrum and the corresponding energy resolution are obtained with the ^{137}Cs radiation source. Among the results of each pixel, the best resolution is 4.8%@662 keV.
Cai, M. S.; Guo, J. H.; Xie, M. G.; Zheng, C. X.
Gamma-spectrometry with Compton suppressed detectors arrays
Recent results of experiments performed with two different Compton-suppressed detectors arrays in Daresbury and Berkeley (/sup 163,164/Yb and /sup 154/Er, respectively), are presented together with a brief description of the national French array presently under construction in Strasbourg. 25 refs., 15 figs.
Schueck, C.; Hannachi, F.; Chapman, R.; Lisle, J.C.; Mo, J.N.; Paul, E.; Love, D.J.G.; Nolan, P.J.; Nelson, A.H.; Walker, P.M.
Small HgCdTe infrared detector arrays from UWA
Single infrared detectors and small arrays find widespread applications in spectroscopy, radiometry, scanning imaging systems, target tracking etc. The technology of such devices based on mercury cadmium telluride (HgCdTe), the material of choice for high performance infrared detectors, has been a subject of intensive research in many countries. Projects conducted in this field at The University of Western Australia resulted
J. Antoszewski; C. A. Musca; J. M. Dell; L. Faraone; M. Wagener; I. Switala; R. Oermann
Turntable Wide Band Infrared Detector Array for Space Situational Awareness
The Center for High Technology Materials at the University of New Mexico has been investigating tunable quantum well\\/dot detectors for infrared detection. These devices have been manufactured in 300 x 256 pixel arrays and can be adjusted to obtain a maximum responsivity to wavelengths ranging from 1 mm to 10 mm by applying an external bias voltage. This detector has
J. Andrews; S. Restaino; S. Teare; S. Krishna; C. Wilcox; T. Martinez
Beam profile monitor for the NSLS vuv ring employing linear photodiode arrays
Among the most important parameters of a storage accelerator are the position and size of the particle beam. In an electron machine, these parameters can be derived from measurements of the emitted synchrotron radiation. We discuss a system which monitors the two-dimensional profile of the synchrotron light in the NSLS vuv ring using commercially available high-resolution linear photosensitive diode arrays. The optical system has been designed to match the size of the image space to the dimensions of the diode sensor area. The scanning rate is automatically adjusted to hold the peaks of the profiles constant over a wide range of beam intensity variations. Video signals from the diode sensors can be readily interfaced to a computer for beam diagnostic purposes. Optics and factors determining the overall resolution of the system are discussed. Preliminary results of beam observations are presented.
Nawrocky, R.J.; Galayda, J.; Yu, L.H.; Shu, D.M.
Low-background detector arrays for infrared astronomy
NASA Technical Reports Server (NTRS)
The status of a program which develops and characterizes integrated infrared (IR) detector array technology for space astronomical applications is described. The devices under development include intrinsic, extrinsic silicon, and extrinsic germanium detectors, coupled to silicon readout electronics. Low-background laboratory test results include measurements of responsivity, noise, dark current, temporal response, and the effects of gamma-radiation. In addition, successful astronomical imagery has been obtained on some arrays from this program. These two aspects of the development combine to demonstrate the strong potential for integrated array technology for IR space astronomy.
Mccreight, C. R.; Estrada, J. A.; Goebel, J. H.; Mckelvey, M. E.; Mckibbin, D. D.; Mcmurray, R. E., Jr.; Weber, T. T.
A Study on the CdZnTe Array Detector
NASA Astrophysics Data System (ADS)
The CdZnTe array detector is a new type of semiconductor detector being rapidly developed in recent years. It possesses a high spatial resolution and a high energy resolution, and it can work at room temperatures. This paper describes the physical properties and working principle of the CdZnTe array detector, as well as the manufacturing technology, including the chip pretreatment, passivation, ohmic electrode preparation, array template selection, and array packaging technology (micro-interconnection). For evaluating the perfor-mance of the detector, the authors have developed successfully a 4 pixel�4 pixel CdZnTe array and an 8 pixel�8 pixel CdZnTe array (with the thicknesses of 5 mm and 2 mm, the pixel size of 2 mm�2 mm, and the gaps of 0.15 mm and 0.2 mm, respectively) in cooperation with the partner. A multi-channel electronic readout system based on the ASIC (Application Specific Integrated Circuit) chip is devel-oped independently for the charge measurement of the 4 pixel�4 pixel CdZnTe array. The energy spectra and corresponding energy resolutions of the 16 pixels are obtained with the 137Cs radiative source, among them the best resolution is 4.8%@662 kev.
Cai, Ming-sheng; Guo, Jian-hua; Xie, Ming-gang; Zheng, Chun-xiao
Adaptive Waveform Correlation Detectors for Arrays: Algorithms for Autonomous Calibration
Waveform correlation detectors compare a signal template with successive windows of a continuous data stream and report a detection when the correlation coefficient, or some comparable detection statistic, exceeds a specified threshold. Since correlation detectors exploit the fine structure of the full waveform, they are exquisitely sensitive when compared to power (STA/LTA) detectors. The drawback of correlation detectors is that they require complete knowledge of the signal to be detected, which limits such methods to instances of seismicity in which a very similar signal has already been observed by every station used. Such instances include earthquake swarms, aftershock sequences, repeating industrial seismicity, and many other forms of controlled explosions. The reduction in the detection threshold is even greater when the techniques are applied to arrays since stacking can be performed on the individual channel correlation traces to achieve significant array gain. In previous years we have characterized the decrease in detection threshold afforded by correlation detection across an array or network when observations of a previous event provide an adequate template for signals from subsequent events located near the calibration event. Last year we examined two related issues: (1) the size of the source region calibration footprint afforded by a master event, and (2) the use of temporally incoherent detectors designed to detect the gross envelope structure of the signal to extend the footprint. In Case 1, results from the PETROBAR-1 marine refraction profile indicated that array correlation gain was usable at inter-source separations out to one or two wavelengths. In Case 2, we found that incoherent detectors developed from a magnitude 6 event near Svalbard were successful at detecting aftershocks where correlation detectors derived from individual aftershocks were not. Incoherent detectors might provide 'seed' events for correlation detectors that then could extend detection to lower magnitudes. This year we addressed a problem long known to limit the acceptance of correlation detectors in practice: the labor intensive development of templates. For example, existing design methods cannot keep pace with rapidly unfolding aftershock sequences. We successfully built and tested an object-oriented framework (as described in our 2005 proposal) for autonomous calibration of waveform correlation detectors for an array. The framework contains a dynamic list of detectors of several types operating on a continuous array data stream. The list has permanent detectors: beam forming power (STA/LTA) detectors which serve the purpose of detecting signals not yet characterized with a waveform template. The framework also contains an arbitrary number of subspace detectors which are launched automatically using the waveforms from validated power detections as templates. The implementation is very efficient such that the computational cost of adding subspace detectors was low. The framework contains a supervisor that oversees the validation of power detections, and periodically halts the processing to revise the portfolio of detectors. The process of revision consists of collecting the waveforms from all detections, performing cross-correlations pairwise among all waveforms, clustering the detections using correlations as a distance measure, then creating a new subspace detector from each cluster. The collection of new subspace detectors replaces the existing portfolio and processing of the data stream resumes. This elaborate scheme was implemented to prevent proliferation of closely-related subspace detectors. The method performed very well on several simple sequences: 2005 'drumbeat' events observed locally at Mt. St. Helens, and the 2003 Orinda, CA aftershock sequence. Our principal test entailed detection of the aftershocks of the San Simeon earthquake using the NVAR array; in this case, the system automatically detected and categorized approximately 2/3 of the events above magnitude 2.8.
Ringdal, F; Harris, D B; Dodge, D; Gibbons, S J
Data Acquisition System of Surface Detector Array of the Telescope Array experiment
The Telescope Array(TA) experiment will investigate the origin of the ultrahigh energy cosmic rays (UHECRs). This experiment is a hybrid observation of an air shower array and fluorescence telescopes installed in Utah, USA. We finised deploying about 500 Surface Detectors(SDs) for AS array to our site in winter of 2006-2007, and start SD operation from April 2007. Effective area of
S. Ozawa; M. Fukushima; S. Kawakami
High-energy interactions in kinetic inductance detectors arrays
NASA Astrophysics Data System (ADS)
The impacts of Cosmic Rays on the detectors are a key problem for space-based missions. We are studying the effects of such interactions on arrays of Kinetic Inductance Detectors (KID), in order to adapt this technology for use on board of satellites. Before proposing a new technology such as the Kinetic Inductance Detectors for a space-based mission, the problem of the Cosmic Rays that hit the detectors during in-flight operation has to be studied in detail. We present here several tests carried out with KID exposed to radioactive sources, which we use to reproduce the physical interactions induced by primary Cosmic Rays, and we report the results obtained adopting different solutions in terms of substrate materials and array geometries. We conclude by outlining the main guidelines to follow for fabricating KID for spacebased applications.
D'Addabbo, A.; Calvo, M.; Goupy, J.; Benoit, A.; Bourrion, O.; Catalano, A.; Macias-Perez, J. F.; Monfardini, A.
Detectors based on silicon photomultiplier arrays for medical imaging applications
Silicon photomultipliers (SiPMs) have experienced a fast development and are now employed in different research fields. The availability of 2D arrays that provide information of the interaction position in the detector has had a high interest for medical imaging. Continuous crystals combined with segmented photodetectors can provide higher efficiency than pixellated crystals and very high spatial resolution. The IRIS group at IFIC is working on the development of detector heads based on continuous crystals coupled to SiPM arrays for different applications, including a small animal PET scanner in collaboration with the Univ. of Pisa and INFN Pisa, and a Compton telescope for dose monitoring in hadron therapy. (authors)
Llosa, G.; Barrio, J.; Cabello, J.; Lacasta, C.; Oliver, J. F. [Instituto de Fisica Corpuscular - IFIC-CSIC/UVEG, Valencia (Spain); Rafecas, M. [Instituto de Fisica Corpuscular - IFIC-CSIC/UVEG, Valencia (Spain); Departamento de Fisica Atomica, Molecular Y Nuclear, Universitat de Valencia, Valencia (Spain); Stankova, V.; Solaz, C. [Instituto de Fisica Corpuscular - IFIC-CSIC/UVEG, Valencia (Spain); Bisogni, M. G.; Del Guerra, A. [Universite di Pisa, INFN Pisa, Pisa (Italy)
The Cosmic Muon Detector Array at Westmont College
NASA Astrophysics Data System (ADS)
At Westmont College we have designed and constructed the Cosmic Muon Detector Array (CMDA), consisting of 8 1-m long position-sensitive scintillator detector bars arranged in two layers of 4 detectors each, one above the other. The purpose of the array has been to measure and monitor the cosmic muon flux over a large angular range in the sky - approximately � 50^o (north-south) by � 30^o (east-west), by correlating event positions between the two layers. The CMDA also monitors the long term north-south sky flux ratio, binned by sidereal hour, to look for possible flux correlations from cosmic sources including the galactic core. The detectors, electronics, and analysis software was modeled after the Modular Neutron Array (MoNA) located at the NSCL, Michigan State University, and simultaneous flux correlations for the CMDA and MoNA were monitored for approximately 1 week. After taking over a year's worth of data, the original array burned in a campus wildfire, which was then replaced by the second generation array (currently in operation). The CMDA serves both as a training ground for students preparing for participation in MoNA collaboration experiments as well as for Westmont student research experience.
Rogers, Warren
Application of a single area array detector for acquistion, tracking and point-ahead in space optical communications
NASA Technical Reports Server (NTRS)
Functions of acquisition, tracking, and point-ahead in space optical communications are being combined into a single system utilizing an area array detector. An analysis is presented of the feasibility concept. The key parameters are: optical power less than 1 pW at 0.86 micrometer, acquisition in less than 30 seconds in an acquisition field of view (FOV) of 1 mrad, tracking with 0.5 microrad rms noise at 1000 Hz update rate, and point ahead transfer function precision of 0.25 microrad over a region of 150 microrad. Currently available array detectors were examined. The most demanding specifications are low output noise, a high detection efficiency, a large number of pixels, and frame rates over 1kHz. A proof of concept (POC) demonstration system is currently being built utilizing the Kodak HS-40 detector (a 128 x 128 photodiode array with a 64 channel CCD readout architecture which can be operated at frame rates as high as 40,000/sec). The POC system implements a windowing scheme and special purpose digital signal processing electronic for matched filter acquisition and tracking algorithms.
Clark, D. L.; Cosgrove, M.; Vanvranken, R.; Park, H.; Fitzmaurice, M.
16 x 25 Ge:Ga detector arrays for FIFI LS
NASA Astrophysics Data System (ADS)
We are developing 2D 16 X 25 pixel detector arrays of both unstressed and stressed Ge:Ga photoconductive detectors for far-infrared astronomy from SOFIA. The arrays, based on earlier 5 X 5 detector arrays used on the KAO, will be for our new instrument, the Far Infrared Field Imaging Line Spectrometer (FIFI LS). The unstressed Ge:Ga detector array will cover the wavelength range from 40 to 120 micrometers , and the stressed Ge:Ga detector array from 120 to 210 micrometers . The detector arrays will be operated with multiplexed integrating amplifiers with cryogenic readout electronics located close to the detector arrays. The design of the stressed detector array and results of current measurements on several prototype 16 pixel linear arrays will be reported. They demonstrate the feasibility of the current concept.
Rosenthal, Dirk; Beeman, Jeffrey W.; Geis, Norbert; Looney, Leslie W.; Poglitsch, Albrecht; Park, Won K.; Raab, Walfried; Urban, Alexander
Reflectance colorimetry measurement system using scanning spectrometer with array detector
NASA Astrophysics Data System (ADS)
A reflectance colorimetry measurement system is constructed using scanning spectrometer with array detector, and the color measurement can be achieved under 45:0 and 0:45 geometry conditions. Typically, there are two types of spectrometer for colorimetry measurement: the scanning spectrometer with single-channel detector requires point-by-point spectral reading, and the measurement is time consuming; array sensor spectrometer (multichannel spectrometer) can completes the measurement in a few milliseconds, but its spectral resolution and range are limited by the array sensor and the optical elements. This colorimetry measurement system is designed for color calibration service, it using a scanning spectrometer with array detector, which divides the board spectral measurement range into sections, and uses the array detector to measure each section respectively, thus achieving the rapid measurement of spectral data with high resolution and wide wavelength range, so as to realized fast color measurement with high precision. The array sensor of the system using a photo diode array (PDA) with 1024 pixel, having a larger dynamic range and better linearity compared to CCD. The grating is rotated with a precision rotation stage, and the rotation angle is calculated basing the parameters of grating and collimator lens, so as to stitch the spectral data of each measurement section., the measurement signal is mutated at the junction point between measurement sections, due to the rotation angle and the shape of grating efficiency curve. The theoretical analysis and experiment shows that the signal mutation at the junction point can be eliminated by comparison measurement of reflectance.
Sun, Ruoduan; Ma, Yu; Dai, Caihong; Chen, Xiaju
An Event Reconstruction Method for the Telescope Array Fluorescence Detectors
We measure arrival directions, energies and mass composition of ultra-high energy cosmic rays with air fluorescence detector telescopes. The longitudinal profile of the cosmic ray induced extensive air shower cascade is imaged on focal plane of the telescope camera. Here, we show an event reconstruction method to obtain the primary information from data collected by the Telescope Array Fluorescence Detectors. In particular, we report on an ''Inverse Monte Carlo (IMC)'' method in which the reconstruction process searches for an optimum solution via repeated Monte Carlo simulations including characteristics of all detectors, atmospheric conditions, photon emission and scattering processes.
Fujii, T.; Ogio, S.; Yamazaki, K. [Graduate Schiool of Science, Osaka City University, Sumiyoshi, Osaka 558-8585 (Japan); Fukushima, M.; Ikeda, D.; Sagawa, H.; Takahashi, Y.; Tameda, Y. [Institute of Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Hayashi, K.; Ishimori, R.; Kobayashi, Y.; Tokuno, H.; Tsunesada, Y. [Graduate School of Science and Engineering, Tokyo Institute of Technology, Meguro, Tokyo 152-8551 (Japan); Honda, K.; Tomida, T. [Graduate School of Medicine and Engineering, University of Yamanashi, Kofu, Yamanashi 400-8511 (Japan); Udo, S. [Faculty of Engineering, Kanagawa University, Yokohama, Kanagawa 221-8686 (Japan)
Calibration and operational data for a compact photodiode detector useful for monitoring the location of moving sources of positron emitting radioisotopes
D-Pace has developed a compact cost-effective gamma detector system based on technology licensed from TRIUMF. These photodiode detectors are convenient for detecting the presence of positron emitting radioisotopes, particularly for the case of transport of radioisotopes from a PET cyclotron to hotlab, or from one location to another in an automated radiochemistry processing unit. This paper describes recent calibration experiments undertaken at the Turku PET Centre for stationary and moving sources of F18 and C11 in standard setups. The practical diagnostic utility of using several of these devices to track the transport of radioisotopes from the cyclotron to hotlab is illustrated. For example, such a detector system provides: a semi-quantitative indication of total activity, speed of transport, location of any activity lost en route and effectiveness of follow-up system flushes, a means of identifying bolus break-up, feedback useful for deciding when to change out tubing.
Marsland, M. G.; Dehnel, M. P.; Theroux, J.; Christensen, T.; Hollinger, C. [D-Pace, Inc. P.O. Box 201, Nelson, B.C., V1L 5P9 (Canada); Johansson, S.; Rajander, J.; Solin, O. [Turku PET Center, Abo Akademi University, Porthansgatan 3, Turku FI-20500 (Finland); Stewart, T. M. [D-Pace, Inc. P.O. Box 201, Nelson, B.C., V1L 5P9 (Canada)
Conceptual design of a hybrid Ge:Ga detector array
NASA Technical Reports Server (NTRS)
For potential applications in space infrared astronomy missions such as the Space Infrared Telescope Facility and the Large Deployable Reflector, integrated arrays of long-wavelength detectors are desired. The results of a feasibility study which developed a design for applying integrated array techniques to a long-wavelength (gallium-doped germanium) material to achieve spectral coverage between 30 and 200 microns are presented. An approach which builds up a two-dimensional array by stacking linear detector modules is presented. The spectral response of the Ge:Ga detectors is extended to 200 microns by application of uniaxial stress to the stack of modules. The detectors are assembled with 1 mm spacing between the elements. Multiplexed readout of each module is accomplished with integration sampling of a metal-oxide-semiconductor (MOS) switch chip. Aspects of the overall design, including the anticipated level of particle effects on the array in the space environment, a transparent electrode design for 200 microns response, estimates of optical crosstalk, and mechanical stress design calculations are included.
Parry, C. M.
Si:Bi switched photoconducttor infrared detector array
NASA Technical Reports Server (NTRS)
A multiplexed infrared detector array is described. The small demonstration prototype consisted of two cryogenically cooled, bismuth doped silicon, extrinsic photoconductor pixels multiplexed onto a single output channel using an on focal plane switch integration sampling technique. Noise levels of the order of 400 to 600 rms electrons per sample were demonstrated for this chip and wire hybrid version.
Eakin, C. E.
A Broadband Superconducting Detector Suitable for Use in Large Arrays
NASA Technical Reports Server (NTRS)
Cryogenic detectors are extremely sensitive and have a wide variety of applications (particularly in astronomy), but are difficult to integrate into large arrays like a modern CCD (charge-coupled device) camera. As current detectors of the cosmic microwave background (CMB) already have sensitivities comparable to the noise arising from the random arrival of CMB photons, the further gains in sensitivity needed to probe the very early Universe will have to arise from large arrays. A similar situation is encountered at other wavelengths. Single-pixel X-ray detectors now have a resolving power of (Delta)E < 5 eV for single 6-keV photons, and future X-ray astronomy missions anticipate the need for 1,000-pixel arrays. Here we report the demonstration of a superconducting detector that is easily fabricated and can readily be incorporated into such an array. Its sensitivity is already within an order of magnitude of that needed for CMB observations, and its energy resolution is similarly close to the targets required for future X-ray astronomy missions.
Day, Peter K.; LeDuc, Henry G.; Mazin, Benjamin A.; Vayonakis, Anastasios; Zmuldzinas, Jonas
High resolution decoding of Multi-Anode Microchannel Array detectors
NASA Technical Reports Server (NTRS)
The Multi-Anode Microchannel Array (MAMA) is a photon counting detector which utilizes a photocathode for photon to electron conversion, a microchannel plate (MCP) for signal amplification and a proximity focused anode array for position sensitivity. The detector electronics decode the position of an event through coincidence discrimination. The decoding algorithm which associates a given event with the appropriate pixel is determined by the geometry of the array. A new algorithm incorporated into a CMOS Application Specific Integrated Circuit (ASIC) decoder which improves the pixel spatial resolution is described. The new algorithm does not degrade the detector throughput and does not require any modifications to the detector tube. The standard MAMA detector has a pixel size of 25 x 25 square microns, but with the new decoder circuit the pixel size is reduced to 12.5 x 12.5 square microns. We have built the first set of decode electronics utilizing the new ASIC chips and report here on the first imaging tests of this system.
Kasle, David B.; Morgan, Jeffrey S.
Keck array and BICEP3: spectral characterization of 5000+ detectors
NASA Astrophysics Data System (ADS)
The inflationary paradigm of the early universe predicts a stochastic background of gravitational waves which would generate a B-mode polarization pattern in the cosmic microwave background (CMB) at degree angular scales. Precise measurement of B-modes is one of the most compelling observational goals in modern cosmology. Since 2011, the Keck Array has deployed over 2500 transition edge sensor (TES) bolometer detectors at 100 and 150 GHz to the South Pole in pursuit of degree-scale B-modes, and Bicep3 will follow in 2015 with 2500 more at 100 GHz. Characterizing the spectral response of these detectors is important for controlling systematic effects that could lead to leakage from the temperature to polarization signal, and for understanding potential coupling to atmospheric and astrophysical emission lines. We present complete spectral characterization of the Keck Array detectors, made with a Martin-Puplett Fourier Transform Spectrometer at the South Pole, and preliminary spectra of Bicep3 detectors taken in lab. We show band centers and effective bandwidths for both Keck Array bands, and use models of the atmosphere at the South Pole to cross check our absolute calibration. Our procedure for obtaining interferograms in the field with automated 4-axis coupling to the focal plane represents an important step towards efficient and complete spectral characterization of next-generation instruments more than 10000 detectors.
Karkare, K. S.; Ade, P. A. R.; Ahmed, Z.; Aikin, R. W.; Alexander, K. D.; Amiri, M.; Barkats, D.; Benton, S. J.; Bischoff, C. A.; Bock, J. J.; Bonetti, J. A.; Brevik, J. A.; Buder, I.; Bullock, E. W.; Burger, B.; Connors, J.; Crill, B. P.; Davis, G.; Dowell, C. D.; Duband, L.; Filippini, J. P.; Fliescher, S. T.; Golwala, S. R.; Gordon, M. S.; Grayson, J. A.; Halpern, M.; Hasselfield, M.; Hildebrandt, S. R.; Hilton, G. C.; Hristov, V. V.; Hui, H.; Irwin, K. D.; Kang, J. H.; Karpel, E.; Kefeli, S.; Kernasovskiy, S. A.; Kovac, J. M.; Kuo, C. L.; Leitch, E. M.; Lueker, M.; Mason, P.; Megerian, K. G.; Netterfield, C. B.; Nguyen, H. T.; O'Brient, R.; Ogburn, R. W.; Pryke, C. L.; Reintsema, C. D.; Richter, S.; Schwarz, R.; Sheehy, C. D.; Staniszewski, Z. K.; Sudiwala, R. V.; Teply, G. P.; Thompson, K. L.; Tolan, J. E.; Turner, A. D.; Vieregg, A.; Weber, A.; Wong, C. L.; Wu, W. L. K.; Yoon, K. W.
A readout for large arrays of microwave kinetic inductance detectors.
Microwave kinetic inductance detectors (MKIDs) are superconducting detectors capable of counting single photons and measuring their energy in the UV, optical, and near-IR. MKIDs feature intrinsic frequency domain multiplexing (FDM) at microwave frequencies, allowing the construction and readout of large arrays. Due to the microwave FDM, MKIDs do not require the complex cryogenic multiplexing electronics used for similar detectors, such as transition edge sensors, but instead transfer this complexity to room temperature electronics where they present a formidable signal processing challenge. In this paper, we describe the first successful effort to build a readout for a photon counting optical/near-IR astronomical instrument, the ARray Camera for Optical to Near-infrared Spectrophotometry. This readout is based on open source hardware developed by the Collaboration for Astronomy Signal Processing and Electronics Research. Designed principally for radio telescope backends, it is flexible enough to be used for a variety of signal processing applications. PMID:22559560
McHugh, Sean; Mazin, Benjamin A; Serfass, Bruno; Meeker, Seth; O'Brien, Kieran; Duan, Ran; Raffanti, Rick; Werthimer, Dan
Applications of pyroelectric materials in array-based detectors.
The development of low-cost, uncooled (room temperature operation) thermal detector arrays has been accelerating in recent years and now commercial products are becoming widely available. As costs come down and volumes rise, these devices are entering the consumer marketplace, providing everything from sophisticated security and people-monitoring devices to hand-held thermal imagers for preventative maintenance and building inspection. Two technologies have established significant market shares in uncooled thermal detector array products. These are resistive microbolometers and pyroelectric ceramics. To address the true mass market, the pyroelectric arrays offer significant cost advantage. In this paper, recent developments in a variety of products based on pyroelectric ceramic arrays are described and their performance and applicability are compared and contrasted with competing technologies. This includes the use of low-element-count arrays for applications in people counting and queue measurement, and the drive for cost-effective imaging arrays for mass-market thermal imaging. The technical challenges in materials production, device development, and low-cost manufacture are reviewed and future opportunities and challenges are outlined. PMID:21937335
Holden, Anthony J
Order-sorting filter transmittance measured with an array detector
NASA Technical Reports Server (NTRS)
The simultaneous measurement of the spectrally and spatially variant transmittance of a linear variable order-sorting filter in a manner that closely resembles its conditions of actual use is described. The transmittance of a prototype order-sorting filter was measured in the 400- to 880-nm wavelength region by illuminating it with the output beam of a spectrophotometer while the filter was attached to the front of a 30 x 32 pixel silicon array detector. The filter was designed to be used in the output beam of a grating spectrometer to prevent the dispersal of higher diffracted orders onto an array detector. Areas of the filter that were spatially matched to the corresponding detector pixel column had measured peak transmittances of about 90 percent that were uniform to within +/- 1.5 percent along a given column. Transmittances for incident wavelengths shorter than the desired bandpass, corresponding to the order overlap region, were measured in the 0.003 range. Line spread function measurements made with the array detector indicated no significant beam spreading caused by inserting the filter into the beam.
Heaney, James B.; Bradley, Scott E.; Bly, Vincent T.; Ewin, Audrey J.; La, Anh T.
Geiger-mode avalanche photodiodes for laser communications and laser radar
Arrays of photon-counting avalanche photodiodes (APDs) enable laser-communications and laser-radar receivers with unprecedented sensitivity at 1.06-mum wavelength. Near room temperature, the best detectors have: 50% photon detection efficiency, 30-kHz dark count rate, and a 1-mus reset time to avoid after-pulsing. Arrays with 64 elements were fabricated in the InGaAsP\\/InP materials system and were bump-bonded to a custom CMOS integrated circuit
B. F. Aull; J. C. Aversa; E. A. Dauler; J. P. Donnelly; E. K. Duerr; J. P. Frechette; J. E. Funk; S. H. Groves; P. I. Hopman; K. E. Jensen; Z.-L. Liau; J. M. Mahan; L. J. Mahoney; K. A. McIntosh; A. Napoleone; D. C. Oakley; E. J. Ouellette; D. C. Shaver; G. M. Smith; S. Verghese; C. J. Vineis
A low capacitance photodiode based on the principle of the solid state drift chamber has been constructed and tested. The device is based on a cellular design with an anode at the centre of each of five cells allowing electrons liberated by ionisation to drift up to 1mm to the read out strip. Results on the performance of the detector, including leakage current, capacitance and drift properties, are presented and compared with simulations.
Avset, B.S.; Evensen, L.; Ellison, J.A.; Hall, G.; Roe, S.; Wheadon, R.; Hansen, T.E.
Superconducting infrared detector arrays with integrated processing circuitry
This paper reports on thin film Josephson junctions used as infrared detectors' which function by a thermal sensing mechanism. In addition to the potential for high sensitivity to a broad range of optical wavelengths, they are ideally suited for integration with superconducting electronics on a single wafer. A project at HYPRES to develop these arrays is directed along two avenues: maximizing the sensitivity of individual Josephson junction detector/SQUID amplifier units and development of superconducting on-chip processing circuitry - multiplexers and A to D converters.
Osterman, D.P.; Marr, P.; Dang, H.; Yao, C.T.; Radparvar, M. (Hypres, Inc., Elmsford, NY (United States))
InGaAs detector arrays hermetic encapsulation technology
In this paper, 256�1 and 512�1 element linear InGaAs detector arrays are hermetic packaged. Some processes were studied, including the structure design, thermoelectric cooler (TEC) heat load performance test, TEC vacuum baking, the window sealing, the seam welding of the cover lid and shell, and so on. The results show that the cooling temperature difference of TEC can reach over
Qinfei Xu; Dafu Liu
A linear array position sensitive detector based on amorphous silicon
A linear array thin film position sensitive detector (LTFPSD) based on hydrogenated amorphous silicon (a-Si:H) is proposed for the first time. Taking advantage of the optical properties presented by a-Si:H devices, we have developed a LTFPSD with 128 integrated elements able to be used in 3D inspections\\/measurements. Each element consists of a one-dimensional LTFPSD, based on a p-i-n diode produced
Rodrigo Martins; Guilherme Lavareda; Elvira Fortunato; Fernando Soares; Lu�s Fernandes; Lu�s Ferreira
Optimal extraction and fingerprint analysis of Cnidii fructus by accelerated solvent extraction and high performance liquid chromatographic analysis with photodiode array and mass spectrometry detections.
A confirmatory and reliable procedure has been developed for extraction and determination of Cnidii fructus by accelerated solvent extraction (ASE) and high-performance liquid chromatography coupled with photodiode array, electrospray ionisation ion trap tandem mass spectrometry and time of flight mass spectrometry (HPLC-PDA-ESI-ITMS(n)/TOF-MS). The determination method enabled the characterisation of sixteen bioactive components in C. fructus and quantification of three major coumarins, namely osthole, imperatorin and isopimpinellin. Response surface methodology (RSM) was employed to optimise the extraction parameters yielding the optimum conditions of ASE (extraction temperature 122 �C, extraction time 5 min and two static cycles). And the total contents of three major coumarins extracted by ASE under the optimum conditions was significantly higher than those by reflux and ultrasonic extraction (P<0.05) with better reproducibility. At last, the proposed method coupled with pattern recognition was applied to analysis of C. fructus from eight different regions in China. PMID:23870916
Gao, Fangyuan; Hu, Yongsheng; Ye, Xiaolan; Li, Ji; Chen, Zhao; Fan, Guorong
Design of a silicon avalanche photodiode pixel with integrated laser diode using back-illuminated crystallographically etched silicon-on-sapphire with monolithically integrated microlens for dual-mode passive and active imaging arrays
NASA Astrophysics Data System (ADS)
There is a growing need in scientific research applications for dual-mode, passive and active 2D and 3D LADAR imaging methods. To fill this need, an advanced back-illuminated silicon avalanche photodiode (APD) design is presented using a novel silicon-on-sapphire substrate incorporating a crystalline aluminum nitride (AlN) antireflective layer between the silicon and R-plane sapphire. This allows integration of a high quantum efficiency silicon APD with a gallium nitride (GaN) laser diode in each pixel. The pixel design enables single photon sensitive, solid-state focal plane arrays (FPAs) with wide dynamic range, supporting passive and active imaging capability in a single FPA. When (100) silicon is properly etched with TMAH solution, square based pyramidal frustum or mesa arrays result with the four mesa sidewalls of the APD formed by (111) silicon planes that intersect the (100) planes at a crystallographic angle, ? c = 54.7�. The APD device is fabricated in the mesa using conventional silicon processing technology. The GaN laser diode is fabricated by epitaxial growth inside of an inverted, etched cavity in the silicon mesa. Microlenses are fabricated in the thinned, and AR-coated sapphire substrate. The APDs share a common, front-side anode contact, and laser diodes share a common cathode. A low resistance (Al) or (Cu) metal anode grid fills the space between pixels and also inhibits optical crosstalk. SOS-APD arrays are flip-chip bump-bonded to CMOS readout ICs to produce hybrid FPAs. The square 27 ?m emitter-detector pixel achieves SNR > 1 in active detection mode for Lambert surfaces at 1,000 meters.
Stern, Alvin G.
Integration of a detector array with an optical waveguide structure
NASA Astrophysics Data System (ADS)
Current research under grant involves integration of a detector array with an optical waveguide structure and applications to signal processing. The present report summarizes progress achieved in Part 1 of this research program (March 15, 1981 - March 14, 1982). The main accomplishments resulting from research performed during this period include a number of accomplishments in the area of laser processing of semiconductors and demonstration of graded index SiO2 waveguides having very low scattering loss. Significant progress was also made with regard to implementation of a log converting array sensor element for charge-coupled device (CCD) image arrays and demonstration of the advantages of edge detection of long wavelength radiation by silicon photodetectors. Results in each of these areas are discussed in the following sections.
Boyd, J. T.
CMOS arrays as chemiluminescence detectors on microfluidic devices.
A simple, low-cost process to integrate complementary metal oxide semiconductor array detectors (CMOSAD) for chemiluminescence is presented, evaluated, and applied to the determination of nitrite in ground water samples. CMOS arrays of different brands (obtained from commercial image sensors) were adapted as chemiluminescence detectors on microfluidic devices. The performance of the CMOSADs was evaluated in the visible zone of the spectrum using a tungsten halogen lamp as light source. Intrinsic parameters assessed included signal stability, spectral response, dark current, and signal-to-noise ratio. Thereafter, the CMOSADs were integrated on microfluidic devices and their performances in quantitative analysis were assessed with the chemiluminometric reaction of hydrogen peroxide with luminol, catalyzed with hexacyanoferrate (III). The parameters assessed were sensitivity, linear range, detection limit, reproducibility, correlation coefficient of the calibration curves, and baseline drift during measurements. The CMOSAD with the best performance was selected to assess the applicability of the developed microfluidic devices with the integrated detector. The microfluidic system permitted the determination of nitrite with both good precision and good recovery values in the analysis of ground water samples. Integration was easily achieved and enabled the development of a simple, low-cost, and feasible alternative to conventional detectors. PMID:20177663
Rodrigues, Eunice R G O; Lapa, Rui A S
Cadmium-zinc telluride detector arrays for synchrotron radiation applications
NASA Astrophysics Data System (ADS)
We have begun a program to develop CZT-based detectors optimized for Synchrotron Radiation (SR) applications. SR provides high brightness beams of hard x-rays, typically in the range 5-100keV. Below 10keV, Peltier-cooled silicon detector arrays can provide high throughput with good spectroscopic resolution. At higher energies, only cryo-cooled germanium detectors or scintillation counters are available. Neither are easily available in large arrays, and scintillation counters lack energy resolution. CZT offers a solution to both these problems. Our development has focused on surface preparation and contact definition technologies which minimize device leakage currents while allowing high-definition contact patterns suitable for SR applications. We have used SR also for diagnostic purposes in these developments, both for detector testing and material characterization. X-ray diffraction, Infrared microscopy and photoemission are all relevant SR-based tools which we are using in our work. As an example, we have observed that bromine remains attached to the CZT surface after chemical etching, and is remarkably persistent in the face of surface cleaning and argon ion sputtering, as revealed by photoemission spectroscopy and x-ray absorption spectroscopy.
Kakuno, Edson M.; Camarda, Giuseppe S.; Siddons, D. P.
Imaging MAMA detector systems. [Multi-Anode Microchannel Array
NASA Technical Reports Server (NTRS)
Imaging multianode microchannel array (MAMA) detector systems with 1024 x 1024 pixel formats have been produced for visible and UV wavelengths; the UV types employ 'solar blind' photocathodes whose detective quantum efficiencies are significantly higher than those of currently available CCDs operating at far-UV and EUV wavelengths. Attention is presently given to the configurations and performance capabilities of state-of-the-art MAMA detectors, with a view to the development requirements of the hybrid electronic circuits needed for forthcoming spacecraft-sensor applications. Gain, dark noise, uniformity, and dynamic range performance data are presented for the curved-channel 'chevron', 'Z-plate', and helical-channel high gain microchannel plate configurations that are currently under evaluation with MAMA detector systems.
Slater, David C.; Timothy, J. G.; Morgan, Jeffrey S.; Kasle, David B.
Frisch-ring CdZnTe detectors have demonstrated good energy resolution for identifying isotopes, <1% FWHM at 662 keV, and good efficiency for detecting gamma rays. We will fabricate and test at Brookhaven National Laboratory an integrated module of a 64-element array of 6 x 6 x 12 mm{sup 3} Frisch-ring detectors, coupled with a readout electronics system. It supports 64 readout channels, and includes front-end electronics, signal processing circuit, USB interface and high-voltage power supply. The data-acquisition software is used to process the data stream, which includes amplitude and timing information for each detected event. This paper describes the design and assembly of the detector modules, readout electronics, and a conceptual prototype system. Some test results are also reported.
Dual APD array readout of LSO crystals: optimization of crystal surface treatment
We are developing a compact positron emission tomography (PET) detector module with a depth of interaction capability (DOI) based on a lutetium oxyorthosilicate (LSO) scintillator array coupled at both ends by avalanche photodiode (APD) arrays. This leads to a detector with high sensitivity that can provide high and uniform image resolution. We report studies on improving the DOI resolution by
Y. Shao; K. Meadors; R. W. Silverman; R. Farrell; L. Cirignano; R. Grazioso; K. S. Shah; S. R. Cherry
Design of micro-sensor-array detector for toxic gas
NASA Astrophysics Data System (ADS)
To quickly measure the trace concentration of the single component toxic gas (e.g. sarin), a micro-array toxic gas detector is designed. A 3 x 3 gas sensor array with metalloporphyrins as sensitive materials is introduced. A micro-capsule that can be easy to be loaded and unloaded is designed for the gas reaction. A fiber-array optical path is designed, which is based on the principle that gas sensors will show different colors after reaction with the toxic gas. The tricolor information about the concentration of gas is collected by the color liner CCD. A control handling system with C8051F021 MCU as the core is implemented and embedded into the detector to perform the functions of gas sampling, data collection and analysis calculation. Data acquisition experimental results show that the proposed scheme can effectively collect the color information after gas reaction. Moreover, the system has many important advantages, such as small size, compact structure, high degree of automation, fast detection speed and high performance-cost ratio, etc.
Liao, Hai-yang; Tian, Peng
Fast, High-Precision Readout Circuit for Detector Arrays
NASA Technical Reports Server (NTRS)
The GEO-CAPE mission described in NASA's Earth Science and Applications Decadal Survey requires high spatial, temporal, and spectral resolution measurements to monitor and characterize the rapidly changing chemistry of the troposphere over North and South Americas. High-frame-rate focal plane arrays (FPAs) with many pixels are needed to enable such measurements. A high-throughput digital detector readout integrated circuit (ROIC) that meets the GEO-CAPE FPA needs has been developed, fabricated, and tested. The ROIC is based on an innovative charge integrating, fast, high-precision analog-to-digital circuit that is built into each pixel. The 128�128-pixel ROIC digitizes all 16,384 pixels simultaneously at frame rates up to 16 kHz to provide a completely digital output on a single integrated circuit at an unprecedented rate of 262 million pixels per second. The approach eliminates the need for off focal plane electronics, greatly reducing volume, mass, and power compared to conventional FPA implementations. A focal plane based on this ROIC will require less than 2 W of power on a 1�1-cm integrated circuit. The ROIC is fabricated of silicon using CMOS technology. It is designed to be indium bump bonded to a variety of detector materials including silicon PIN diodes, indium antimonide (InSb), indium gallium arsenide (In- GaAs), and mercury cadmium telluride (HgCdTe) detector arrays to provide coverage over a broad spectral range in the infrared, visible, and ultraviolet spectral ranges.
Rider, David M.; Hancock, Bruce R.; Key, Richard W.; Cunningham, Thomas J.; Wrigley, Chris J.; Seshadri, Suresh; Sander, Stanley P.; Blavier, Jean-Francois L.
Cerenkov radiators for photodiodes
Several materials have been examined for use as Cerenkov converters in front of photodiodes in an effort to find a gamma detector system that has more sensitivity than a Compton detector but makes little sacrifice in bandwidth. Suprasil (fused silica) and UVT Lucite (acrylic) were 10-100 times more sensitive than a Compton detector and provided almost the same bandwidth. Barium fluoride provided almost 1000 times the sensitivity, but with a factor of 3 or 4 reduction in bandwidth. Relative sensitivities are strongly dependent on beam composition; the Cerenkov package is less sensitive to a pure ..gamma..-ray beam than to a ..gamma..-electron shower beam. Hence, beam composition must be considered in any application of these detectors.
Toevs, J.W.; Young, C.S.; Zagarino, P.A.; Seno, R.D.
Development of high performance Avalanche Photodiodes and dedicated analog systems for HXI/SGD detectors onboard the Astro-H mission
NASA Astrophysics Data System (ADS)
Hard X-ray Imager and Soft Gamma-ray Detector are being developed as onboard instruments for the Astro-H mission, which is scheduled for launch in 2014. In both detectors, BGO scintillators play key roles in achieving high sensitivity in low Earth orbit (LEO), by generating active veto signals to reject cosmic-ray events and gamma-ray backgrounds from radio-activated detector materials. In order to maximize background rejection power, it is also important to minimize the energy threshold of this shield. As a readout sensor of weak scintillation light from a number of BGO crystals in a complicated detector system, high performance, reverse-type Avalanche Photodiodes (APDs), with an effective area of 10�10 mm2 are being employed, instead of bulky photomultiplier tubes (PMTs).Another advantage of using APDs is their low power consumption, although the relatively low gain of APDs (compared to conventional PMTs) requires dedicated analog circuits for noise suppression. In this paper, we report on the development and performance of APD detectors specifically designed for the Astro-H mission. In addition to APD performance, various environmental tests, including radiation hardness and qualification thermal cycling, will be described in detail. Moreover, a dedicated charge sensitive amplifier and analog filters are newly developed and tested here to optimize the performance of APDs to activate fast veto signals within a few ?s from the BGO trigger. We will also report on overall performance testing of a prototype BGO detector system that mimics the data acquisition system onboard Astro-H.
Saito, T.; Nakamori, T.; Yoshino, M.; Mizoma, H.; Kataoka, J.; Kawakami, K.; Yatsu, Y.; Ohno, M.; Goto, K.; Hanabata, Y.; Takahashi, H.; Fukazawa, Y.; Sasano, M.; Torii, S.; Uchiyama, H.; Nakazawa, K.; Makishima, K.; Watanabe, S.; Kokubun, M.; Takahashi, T.; Mori, K.; Tajima, H.; Astro-H HXI/SGD Team
Undersampling Correction for Array Detector-Based Satellite Spectrometers
NASA Technical Reports Server (NTRS)
Array detector-based instruments are now fundamental to measurements of ozone and other atmospheric trace gases from space in the ultraviolet, visible, and infrared. The present generation of such instruments suffers, to a greater or lesser degree, from undersampling of the spectra, leading to difficulties in the analysis of atmospheric radiances. We provide extended analysis of the undersampling suffered by modem satellite spectrometers, which include Global Ozone Monitoring Experiment (GOME), Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY), Ozone Monitoring Instrument (OMI), and Ozone Mapping and Profiler Suite (OMPS). The analysis includes basic undersampling, the effects of binning into separate detector pixels, and the application of high-resolution Fraunhofer spectral data to correct for undersampling in many useful cases.
Chance, Kelly; Kurosu, Thomas P.; Sioris, Christopher E.
Nuclear structure through moment measurements: Exploiting ?-ray detector arrays with ancillary detectors
Experimental methods to measure the magnetic moments of short-lived excited states in beams of rare isotopes are outlined. The emphasis is on the so-called High-Velocity Transient-Field (HVTF) and the Recoil in Vacuum (RIV) methods, and the role of ?-ray detector arrays with ancillary detectors. Insights into the structure of neutron-rich nuclei through such measurements on radioactive beams are discussed. Opportunities for the future development of these techniques, for applications to both stable and radioactive beams, are explored.
Stuchbery, Andrew E. [Department of Nuclear Physics, The Australian National University, Canberra, ACT 0200 (Australia)
Two detector arrays for fast neutrons at LANSCE
NASA Astrophysics Data System (ADS)
The neutron spectrum from neutron-induced fission needs to be known in designing new fast reactors, predicting criticality for safety analyses, and developing techniques for global security application. The experimental data base of fission neutron spectra is very incomplete and most present evaluated libraries are based on the approach of the Los Alamos Model. To validate these models and to provide improved data for applications, a program is underway to measure the fission neutron spectrum for a wide range of incident neutron energies using the spallation source of fast neutrons at the Weapons Neutron Research (WNR) facility at the Los Alamos Neutron Science Center (LANSCE). In a double time-of-flight experiment, fission neutrons are detected by arrays of neutron detectors to increase the solid angle and also to investigate possible angular dependence of the fission neutrons. The challenge is to measure the spectrum from low energies, down to 100 keV or so, to energies over 10 MeV, where the evaporation-like spectrum decreases by 3 orders of magnitude from its peak around 1 MeV. For these measurements, we are developing two arrays of neutron detectors, one based on liquid organic scintillators and the other on 6Li-glass detectors. The range of fission neutrons detected by organic liquid scintillators extends from about 600 keV to well over 10 MeV, with the lower limit being defined by the limit of pulse-shape discrimination. The 6Li-glass detectors have a range from very low energies to about 1 MeV, where their efficiency then becomes small. Various considerations and tests are in progress to understand important contributing factors in designing these two arrays and they include selection and characterization of photomultiplier tubes (PM), the performance of relatively thin (1.8 cm) 6Li-glass scintillators on 12.5 cm diameter PM tubes, use of 17.5 cm diameter liquid scintillators with 12.5 cm PM tubes, measurements of detector efficiencies with tagged neutrons from the WNR/LANSCE neutron beam, and efficiency calibration with 252Cf spontaneous fission neutrons. Design considerations and test results are presented.
Haight, R. C.; Lee, H. Y.; Taddeucci, T. N.; O'Donnell, J. M.; Perdue, B. A.; Fotiades, N.; Devlin, M.; Ullmann, J. L.; Laptev, A.; Bredeweg, T.; Jandel, M.; Nelson, R. O.; Wender, S. A.; White, M. C.; Wu, C. Y.; Kwan, E.; Chyzh, A.; Henderson, R.; Gostic, J.
The hybrid energy spectrum of Telescope Array's Middle Drum Detector and surface array
NASA Astrophysics Data System (ADS)
The Telescope Array experiment studies ultra high energy cosmic rays using a hybrid detector. Fluorescence telescopes measure the longitudinal development of the extensive air shower generated when a primary cosmic ray particle interacts with the atmosphere. Meanwhile, scintillator detectors measure the lateral distribution of secondary shower particles that hit the ground. The Middle Drum (MD) fluorescence telescope station consists of 14 telescopes from the High Resolution Fly's Eye (HiRes) experiment, providing a direct link back to the HiRes measurements. Using the scintillator detector data in conjunction with the telescope data improves the geometrical reconstruction of the showers significantly, and hence, provides a more accurate reconstruction of the energy of the primary particle. The Middle Drum hybrid spectrum is presented and compared to that measured by the Middle Drum station in monocular mode. Further, the hybrid data establishes a link between the Middle Drum data and the surface array. A comparison between the Middle Drum hybrid energy spectrum and scintillator Surface Detector (SD) spectrum is also shown.
Abbasi, R. U.; Abe, M.; Abu-Zayyad, T.; Allen, M. G.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Chae, M. J.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, W. R.; Fujii, T.; Fukushima, M.; Goto, T.; Hanlon, W.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Honda, K.; Ikeda, D.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kawata, K.; Kido, E.; Kim, H. B.; Kim, J. H.; Kim, J. H.; Kitamura, S.; Kitamura, Y.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lim, S. I.; Lundquist, J. P.; Machida, K.; Martens, K.; Matsuda, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Mukai, K.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nonaka, T.; Nozato, A.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, H. S.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzawa, T.; Takamura, M.; Takeda, M.; Takeishi, R.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Uchihori, Y.; Udo, S.; Urban, F.; Vasiloff, G.; Wong, T.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yashiro, K.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.
Fluorometric flow-immunoassay for alkylphenol polyethoxylates on a microchip containing a fluorescence detector comprised of an organic light emitting diode and an organic photodiode.
A compact fluorescence detector was constructed on a microchip from an organic light emitting diode (OLED) as the light source and an organic photodiode (OPD) as the photo-detector and was used in an immunoassay for alkylphenol polyethoxylates (APE). The OLED based on a terbium complex emitted a sharp light at the main wavelength of 546 nm with a full width at half maximum of 9 nm. The incident photo-to-current conversion efficiency (IPCE) of the OPD fabricated with Fullerene 70 (C70) and tris[4-(5-phenylthiopen-2-yl)phenyl]-amine (TPTPA) was approximately 44% for light at a wavelength of 586 nm. The performance of the fluorescence detector was evaluated for the determination of resorufin (?(em)=586 nm) and the photocurrent of the OPD due to the fluorescence of resorufin was proportional to the concentration of resorufin in the range from 0 to 18 �M with a detection limit (S/N=3) of 0.6 �M. The fluorescence detector was successfully utilized in a competitive enzyme-linked immunosorbent assay for APE, where an anti-APE antibody was immobilized on the surface of the channel of the Polydimethylsiloxane (PDMS) microchip or on the surface of magnetic microbeads. After an immunoreaction with a sample solution of APE containing a horse radish peroxidase (HRP)-labeled APE, the fluorescence of resorufin generated just after introduction of a mixed solution of Amplex Red and H2O2 was measured using the fluorescence detector. The calibration curve for the photocurrent signals of the OPD due to the fluorescence of resorufin against the logarithmic concentration of APE was sigmoidal in shape. The detection limits defined as IC80 were ca. 1 ppb and ca. 2 ppb, respectively, for the methods using the anti-APE antibody immobilized on the surface of the microchannel and in the case where the antibody was immobilized on the surface of magnetic microbeads. PMID:25618638
Liu, Rong; Ishimatsu, Ryoichi; Yahiro, Masayuki; Adachi, Chihaya; Nakano, Koji; Imato, Toshihiko
The application of UV diode array detection in high-performance liquid chromatographic (HPLC) identification and quantitation of several classes of synthetic and commercially available alkylated nucleobases is investigated. uantitative spectral overlays of these compounds to meth...
A sub-millimeter resolution PET detector module using a multi-pixel photon counter array
A PET block detector module using an array of sub-millimeter lutetium oxyorthosilicate (LSO) crystals read out by an array of surface-mount, semiconductor photosensors has been developed. The detector consists of a LSO array, a custom acrylic light guide, a 3 � 3 multi-pixel photon counter (MPPC) array (S10362-11-050P, Hamamatsu Photonics, Japan) and a readout board with a charge division resistor
Tae Yong Song; Heyu Wu; Sergey Komarov; Stefan B. Siegel; Yuan-Chuan Tai
Advanced Antenna-Coupled Superconducting Detector Arrays for CMB Polarimetry
NASA Astrophysics Data System (ADS)
We are developing high-sensitivity millimeter-wave detector arrays for measuring the polarization of the cosmic microwave background (CMB). This development is directed to advance the technology readiness of the Inflation Probe mission in NASA's Physics of the Cosmos program. The Inflation Probe is a fourth-generation CMB satellite that will measure the polarization of the CMB to astrophysical limits, characterizing the inflationary polarization signal, mapping large-scale structure based on polarization induced by gravitational lensing, and mapping Galactic magnetic fields through measurements of polarized dust emission. The inflationary polarization signal is produced by a background of gravitational waves from the epoch of inflation, an exponential expansion of space-time in the early universe, with an amplitude that depends on the physical mechanism producing inflation. The inflationary polarization signal may be distinguished by its unique 'B-mode' vector properties from polarization from the density variations that predominantly source CMB temperature anisotropy. Mission concepts for the Inflation Probe are being developed in the US, Europe and Japan. The arrays are based on planar antennas that provide integral beam collimation, polarization analysis, and spectral band definition in a compact lithographed format that eliminates discrete fore-optics such as lenses and feedhorns. The antennas are coupled to transition-edge superconducting bolometers, read out with multiplexed SQUID current amplifiers. The superconducting sensors and readouts developed in this program share common technologies with NASA X-ray and FIR detector applications. Our program targets developments required for space observations, and we discuss our technical progress over the past two years and plans for future development. We are incorporating arrays into active sub-orbital and ground-based experiments, which advance technology readiness while producing state of the art CMB polarization measurements.
Bock, James
Capillary Array Waveguide Amplified Fluorescence Detector for mHealth
Mobile Health (mHealth) analytical technologies are potentially useful for carrying out modern medical diagnostics in resource-poor settings. Effective mHealth devices for underserved populations need to be simple, low cost, and portable. Although cell phone cameras have been used for biodetection, their sensitivity is a limiting factor because currently it is too low to be effective for many mHealth applications, which depend on detection of weak fluorescent signals. To improve the sensitivity of portable phones, a capillary tube array was developed to amplify fluorescence signals using their waveguide properties. An array configured with 36 capillary tubes was demonstrated to have a ~100X increase in sensitivity, lowering the limit of detection (LOD) of mobile phones from 1000 nM to 10 nM for fluorescein. To confirm that the amplification was due to waveguide behavior, we coated the external surfaces of the capillaries with silver. The silver coating interfered with the waveguide behavior and diminished the fluorescence signal, thereby proving that the waveguide behavior was the main mechanism for enhancing optical sensitivity. The optical configuration described here is novel in several ways. First, the use of capillaries waveguide properties to improve detection of weak florescence signal is new. Second we describe here a three dimensional illumination system, while conventional angular laser waveguide illumination is spot (or line), which is functionally one-dimensional illumination, can illuminate only a single capillary or a single column (when a line generator is used) of capillaries and thus inherently limits the multiplexing capability of detection. The planar illumination demonstrated in this work enables illumination of a two dimensional capillary array (e.g. x columns and y rows of capillaries). In addition, the waveguide light propagation via the capillary wall provides a third dimension for illumination along the axis of the capillaries. Such an array can potentially be used for sensitive analysis of multiple fluorescent detection assays simultaneously. The simple phone based capillary array approach presented in this paper is capable of amplifying weak fluorescent signals thereby improving the sensitivity of optical detectors based on mobile phones. This may allow sensitive biological assays to be measured with low sensitivity detectors and may make mHealth practical for many diagnostics applications, especially in resource-poor and global health settings. PMID:24039345
Balsam, Joshua; Bruck, Hugh Alan; Rasooly, Avraham
Responsivity performance of extended wavelength InGaAs shortwave infrared detector arrays
NASA Astrophysics Data System (ADS)
InxGa1-xAs ternary compound is suitable for detector applications in the shortwave infrared (1-3 ?m) band. In this paper, we reported on mesa type and planar type extended wavelength InGaAs detector arrays. The photo response performances of these detector arrays were investigated. The blackbody responsivities (Rbb) of these detectors at different temperatures were measured, and the results showed that the Rbb of planar type arrays was higher than that of the conventionally passivated mesa type, but the mesa arrays fabricated by improved passivating technique has the highest responsivity. The reason of the Rbb difference between the arrays was analyzed, and it is found that the difference mostly comes from the minority carrier lifetime, which is related to the device structures and fabrication processes. With the optimized fabrication processes the mesa type arrays can obtain higher blackbody responsivity even more than the planar arrays.
Li, Tao; Deng, Shuang-yan; Li, Xue; Shao, Xiu-mei; Tang, Heng-jing; Gong, Hai-mei
Determination of plant hormones in fertilizers by high-performance liquid chromatography with photodiode array detection: method development and single-laboratory validation.
A simple and reliable high-performance liquid chromatographic method that uses photodiode array detection was developed for the simultaneous determination of 12 native and synthetic plant hormones, i.e., plant growth regulators (PGRs), in fertilizers, such as 1-naphthol, 2,4-dichlorophenoxyacetic acid, 4-(2,4-dichlorophenoxy)butyric acid, 4-chlorophenoxyacetic acid, indole-3-acetic acid, 4-(3-indolyl)butyric acid, dichlorprop, (4-chloro-2-methylphenoxy)acetic acid, alpha-naphthaleneacetic acid, 1-naphthaleneacetamide, beta-naphthoxyacetic acid, and thidiazuron. The method was experimentally validated for routine regulatory application, and the following analytical parameters were assessed for all PGRs studied: linearity; specificity; precision (relative standard deviation) and accuracy, both measured at 3 concentration levels (0.1, 0.05, and 0.01%, w/w); ruggedness; limit of detection; and limit of quantification. Results were satisfactory for all method validation parameters tested and for all PGRs studied, demonstrating the suitability of the method for the determination of PGRs in fertilizers. The uncertainty of measurement was also estimated at 3 concentration levels for all PGRs by using the approach of the International Organization for Standardization, described in its Guide to the Expression of Uncertainty in Measurement. The method was applied to 20 samples of liquid fertilizer with declared biostimulant properties. PMID:19202783
Gambino, Grazia Laura; Pagano, Pietro; Scordino, Monica; Sabatino, Leonardo; Scollo, Emanuele; Traulo, Pasqualino; Gagliano, Giacomo
Determination of the polyphenolic content of a Capsicum annuum L. extract by liquid chromatography coupled to photodiode array and mass spectrometry detection and evaluation of its biological activity.
The present study was aimed to investigate the polyphenolic profile of a pepper (Capsicum annuum L.) extract from Algeria and evaluate its biological activity. The total polyphenol content of the extract was determined as 1.373�mg of gallic acid equivalents (�0.0046), whereas the flavonoids were determined as 0.098�mg of quercetin (�0.0015). The determination of the complete polyphenolic profile of the extract was achieved by liquid chromatography with an RP-amide column in combination with photodiode array and mass spectrometry detection through an electrospray ionization interface. A total of 18 compounds were identified, of which five were reported for the first time in the sample tested. Quercetin rhamnoside was the most abundant compound (82.6 ?g/g of fresh pepper) followed by quercetin glucoside (19.86 ?g/g). The antioxidant activity and antimicrobial effects were also determined. For the antimicrobial tests assessed against Gram-positive and Gram-negative bacteria, kaempferol showed the strongest inhibitory effect followed by quercetin and caffeic acids. In the study of the cytotoxicity of the extract, the cancer cells (U937) were more affected than the normal cells (peripheral blood mononucleated cells), with more than 62% inhibition at the highest concentration. PMID:25378270
Mokhtar, Meriem; Soukup, Jan; Donato, Paola; Cacciola, Francesco; Dugo, Paola; Riazi, Ali; Jandera, Pavel; Mondello, Luigi
Ultrasound-assisted solid-phase extraction coupled with photodiode-array and fluorescence detection for chemotaxonomy of isoflavone phytoestrogens in Trifolium L. (Clover) species.
Detailed chemotaxonomic studies were undertaken to establish the qualitative profile and real amounts of the pharmacologically active isoflavone aglycones genistein, daidzein, formononetin, and biochanin A in aerial parts of thirteen Trifolium L. (clover) species, native to Poland. A newly elaborated micropreparative technique--SPE--on BakerBond octadecyl, cyclohexyl, and phenyl cartridges was used in combination with ultrasound-assisted extraction for isolation of isoflavone aglycones from hydrolyzed samples. The effectiveness of all three SPE sorbents in the purification of plant extracts was compared and very high recoveries (>96%) were documented for four isoflavones. Classical photodiode-array and very sensitive fluorescence detection, coupled with reversed-phase high-performance liquid chromatography (RP-HPLC), were employed to obtain the most reliable qualitative and quantitative results. Chemotaxonomic differences combined with flower color variability were demonstrated within thirteen clover species. Concentration levels of particular isoflavones in ten Trifolium species possessing flowers with white, pink, or purple-red corolla ranged from approximately 3 to approximately 3300 microg/g dry weight, while in three yellow flowering clovers (T. aureum, T. dubium, and T. campestre) isoflavone compounds have not been detected at all. RSD values, determined for intra- and inter-day precision of the quantitative results, were not higher than 6.2% and 7.1%, respectively. PMID:19226567
Zg�rka, Grazyna
Assessment study of infrared detector arrays for low-background astronomical research
NASA Technical Reports Server (NTRS)
The current state-of-the-art of infrared detector arrays employing charge coupled devices (CCD) or charge injection devices (CID) readout are assessed. The applicability, limitations and potentials of such arrays under the low-background astronomical observing conditions of interest for SIRFT (Shuttle Infrared Telescope Facility) are determined. The following are reviewed: (1) monolithic extrinsic arrays; (2) monolithic intrinsic arrays; (3) charge injection devices; and (4) hybrid arrays.
Ando, K. J.
Terahertz spectroscopy with a holographic Fourier transform spectrometer plus array detector using coherent synchrotron radiation
By use of coherent terahertz synchrotron radiation, we experimentally tested a holographic Fourier transform spectrometer coupled to an array detector to determine its viability as a spectral device. Somewhat surprisingly, the overall performance strongly depends on the absorptivity of the birefringent lithium tantalate pixels in the array detector.
Nikolay I. Agladz, John Klopf, Gwyn Williams, Albert J. Sievers
New results from the Antarctic Muon And Neutrino Detector Array K. Woschnagg for the AMANDA Collaboration
1 New results from the Antarctic Muon And Neutrino Detector Array K. Woschnagg for the AMANDA. Rawlins j , E. Resconi a , W. Rhode f , M. Ribordy l , S. Richter j , J. Rodr�??�guez Martino k , H And Neutrino Detector Array (AMANDA) on searches for highenergy neutrinos of extraterrestrial origin. We have
Woschnagg, Kurt
HgCdTe e-APD detector arrays with single photon sensitivity for space lidar applications
NASA Astrophysics Data System (ADS)
A multi-element HgCdTe electron initiated avalanche photodiode (e-APD) array has been developed for space lidar. The detector array was fabricated with 4.3?m cutoff HgCdTe with a spectral response from 0.4 to 4.3 ?m. We have demonstrated a 4x4 e-APD array with 80 ?m square elements followed by a custom cryogenic CMOS read-out integrated circuit (ROIC). The device operates at 77K inside a small closed-cycle cooler-Dewar with the support electronics integrated in a field programmable gate array. Measurements showed a unity gain quantum efficiency of about 90% at 1.5-1.6 ?m wavelength. The bulk dark current of the HgCdTe e-APD at 77K was less than 50,000 input referred electrons/s at 12 V APD bias where the APD gain was 620 and the measured noise equivalent power (NEP) was 0.4 fW/Hz1/2. The electrical bandwidth of the device was about 6 MHz, mostly limited by the ROIC, but sufficient for the lidar application. Although the devices were designed for low bandwidth pulse detections, the high gain and low dark current enabled them to be used for single photon detections. Because the APD was biased below the break-down voltage, the output is linear to the input signal and there were no nonlinear effect such as dead-time and afterpulsing, and no need for gated operation. A new series of HgCdTe e-APDs have also been developed with a much wider bandwidth ROIC and higher APD gain, which is expected to give a much better performance in single photon detections.
Sun, Xiaoli; Abshire, James B.; Beck, Jeffrey D.
Method of fabricating multiwavelength infrared focal plane array detector
NASA Technical Reports Server (NTRS)
A multiwavelength local plane array infrared detector is included on a common substrate having formed on its top face a plurality of In.sub.x Ga.sub.1-x As (x.ltoreq.0.53) absorption layers, between each pair of which a plurality of InAs.sub.y P.sub.1-y (y.ltoreq.1) buffer layers are formed having substantially increasing lattice parameters, respectively, relative to said substrate, for preventing lattice mismatch dislocations from propagating through successive ones of the absorption layers of decreasing bandgap relative to said substrate, whereby a plurality of detectors for detecting different wavelengths of light for a given pixel are provided by removing material above given areas of successive ones of the absorption layers, which areas are doped to form a pn junction with the surrounding unexposed portions of associated absorption layers, respectively, with metal contacts being formed on a portion of each of the exposed areas, and on the bottom of the substrate for facilitating electrical connections thereto.
Forrest, Stephen R. (Inventor); Olsen, Gregory H. (Inventor); Kim, Dong-Su (Inventor); Lange, Michael J. (Inventor)
Fatal Datura poisoning: identification of atropine and scopolamine by high performance liquid chromatography/photodiode array/mass spectrometry.
A forensic method comprising solid phase extraction and HPLC analysis was developed for the detection and confirmation of atropine and scopolamine, the main toxic alkaloids of Datura stramonium and Datura ferox. This method allowed the direct coupling of an electrospray (ZMD) mass selective detector to the HPLC system. Under these conditions, atropine and scopolamine were well separated from other components and detected on the PDA (LOD = 1 microg/ml) and ZMD (LOD(atropine) = 10 pg/ml; LOD(scopolamine) = 100 pg/ml) detectors. Four geographically isolated populations of each of D. stramonium and D. ferox were analysed for seed alkaloids and it was found that the two species were diagnostically different in their atropine-scopolamine ratios. The optimised HPLC method was used to analyse three viscera samples of an adult Caucasian male whose death was ascribed to a fatal heart attack. Atropine and scopolamine were detected in the stomach and its contents, which contained Datura seeds. The chemical profile of the seeds found in the stomach contents was similar to those from four geographically different D. ferox plants. PMID:15374592
Steenkamp, P A; Harding, N M; van Heerden, F R; van Wyk, B-E
Coherent summation of spatially distorted Doppler lidar signals using a two-dimensional heterodyne detector array
We have investigated the improvement in the signal-to-noise ratio for a coherent Doppler lidar through the use of a multi-element heterodyne detector array. Such an array enables the spatial summation of atmospheric refractive turbulence induced speckles, and time varying target speckles. Our recent experiments have shown that the non-coherent summation of the lidar signals from a heterodyne detector array can
Kin Pui Chan; Dennis K. Killinger
Two-dimensional phased arrays of sources and detectors for depth discrimination in diffuse optical imaging
Two-dimensional phased arrays of sources and detectors for depth discrimination in diffuse optical, multidetector phased-array ap- proach to diffuse optical imaging that is based on postprocessing continuous of elements. We find that the proposed phased-array method is able to separate cylinders at differ- ent depths
Fantini, Sergio
Stressed and unstressed Ge:Ga detector arrays for airborne astronomy
NASA Technical Reports Server (NTRS)
The construction and operation of 2D arrays of both unstressed and stressed Ge:Ga photoconductive detectors for far-IR astronomy from the Kuiper Airborne Observatory is presented. The 25 element (5 x 5) arrays are designed for a new cryogenically cooled spectrometer. The 2D spatial array described has the advantage of absolute registry between pixels in a map.
Stacey, G. J.; Beeman, J. W.; Haller, E. E.; Geis, N.; Poglitsch, A.; Rumitz, M.
Leakage mechanisms and potential performance of molecular-beam epitaxially grown GaInAsSb 2.4 {mu}m photodiode detectors
We report on the growth, processing, and characterization of uncoated, unpassivated GaInAsSb detector mesa photodiodes with a cutoff wavelength of 2.4 {mu}m. We find peak room temperature specific detectivity value of 6x10{sup 10} cm Hz{sup 1/2}/W and maximum zero-bias resistivity of 25 {omega} cm{sup 2}. The zero-bias resistivities of mesas with areas ranging from 50{sup 2} {mu}m{sup 2} to 1 mm{sup 2} were found to be limited by generation-recombination currents at mesa sidewalls. At low temperatures, devices were limited by Ohmic leakage, which is likely due to the formation of oxides on the sidewalls. After 6 months of aging, Ohmic leakage becomes the limiting factor at room temperature as well. Based on experimentally obtained material parameters in this and other studies, an upper limit D* and R{sub 0}A were estimated for GaInAsSb materials and compared to those HgCdTe and InGaAs.
Prineas, J. P.; Yager, J.; Seyedmohamadi, S. [Department of Physics and Astronomy, Optical Sciences and Technology Center, University of Iowa, Iowa City, Iowa 52242 (United States); Olesberg, J. T. [Department of Chemistry, Optical Sciences and Technology Center, University of Iowa, Iowa City, Iowa 52242 (United States)
Investigation of depth-of-interaction by pulse shape discrimination in multicrystal detectors read out by avalanche photodiodes
The measurement of depth of interaction (DOI) within detectors is necessary to improve resolution uniformity across the FOV of small diameter PET scanners. DOI encoding by pulse shape discrimination (PSD) has definite advantages as it requires only one readout per pixel and it allows DOI measurement of photoelectric and Compton events. The PSD time characteristics of various scintillators were studied
A. Saoudi; C. Pepin; F. Dion; M. Bentourkin; R. Lecomte; M. Andreacu; M. Casey; R. Nutt; H. Dautet
Investigation of depth-of-interaction by pulse shape discrimination in multicrystal detectors read out by avalanche photodiodes
The measurement of depth of interaction (DOI) within detectors is necessary to improve resolution uniformity across the FOV of small diameter PET scanners. DOI encoding by pulse shape discrimination (PSD) has definite advantages as it requires only one readout per pixel and it allows DOI measurement of photoelectric and Compton events. The PSD time characteristics of various scintillators were studied
A. Saoudi; C. M. Pepin; F. Dion; M. Bentourkia; R. Lecomte; M. Andreaco; M. Casey; R. Nutt; H. Dautet
Stable, high quantum efficiency silicon photodiodes for vacuum-UV applications
NASA Technical Reports Server (NTRS)
Silicon photodiodes have been developed by defect-free phosphorus diffusion having practically no carrier recombination at the SiSiO2 interface or in the front diffused region. The quantum efficiency of these photodiodes was found to be around 120 percent at 100 nm. Unlike the previously tested silicon photodiodes, the developed photodiodes exhibit extremely stable quantum efficiency over extended periods of time. The possibility of using these photodiodes as vacuum ultraviolet detector standards is being currently investigated.
Korde, Raj; Canfield, L. Randall; Wallis, Brad
Simultaneous determination of thirteen beta-blockers and one metabolite by gradient high-performance liquid chromatography with photodiode-array UV detection.
A new rapid and sensitive high-performance liquid chromatography (HPLC) method has been developed for the simultaneous identification and quantification in human plasma of the 13 most commonly prescribed beta-blockers and one active metabolite-atenolol, sotalol, diacetolol, carteolol, nadolol, pindolol, acebutolol, metoprolol, celiprolol, oxprenolol, labetalol, propranolol, tertatolol and betaxolol. It involves liquid-liquid extraction procedures followed by liquid chromatography coupled to photodiode-array UV detection with a fixed wavelength at 220 nm for quantification. Compounds were separated on a 5 microm Hypurity C(18) (ThermoHypersil) analytical column (250 mm x 4.6 mm, i.d.) using a gradient of acetonitrile-phosphate buffer pH 3.8 at a flow rate of 1.0 ml/min. The total analysis time was 26 min per sample. Extraction recoveries were between 74 and 113% for the polar compounds and between 20 and 56% for the most apolar compounds. Calibration lines were linear in the range from 25 to 1000 ng/ml for all compounds excepted carteolol and nadolol (50-1000 ng/ml), all of them with coefficients of determination (r2 values) >/=0.994. Limits of detection (LODs) ranged from 5 to 10 ng/ml. Intra-assay and inter-assay precision and accuracy were studied at two concentration levels (100 and 500 ng/ml). The intra-assay coefficients of variation (CVs) for all compounds were = 8.3% and all inter-assays CVs were below 12.6%. The intra-assay and inter-assay accuracies for all compounds were found to be within 91.4 and 105.6% at 100 ng/ml and within 94.1 and 107.4% at 500 ng/ml. Thus, the performance of the method described allows its use in toxicological screening and in quantification of the most prescribed beta-blockers drugs. PMID:15066710
Delamoye, Magali; Duverneuil, Charlotte; Paraire, Fran�ois; de Mazancourt, Philippe; Alvarez, Jean-Claude
Progress of Multicolor Single Detector to Detector Array Development for Remote Sensing
NASA Technical Reports Server (NTRS)
Knowledge of the spatial and temporal distribution of atmospheric species such as CO2, O3, H2O, and CH4 is important for understanding the chemistry and physical cycles involving Earth s atmosphere. Although several remote sensing techniques are suitable for such measurements they are considered high cost techniques involving complicated instrumentation. Therefore, simultaneous measurement of atmospheric species using a single remote sensing instrument is significant for minimizing cost, size and complexity. While maintaining the instrument sensitivity and range, quality of multicolor detector, in terms of high quantum efficiency and low noise are vital for these missions. As the first step for developing multicolor focal plan array, the structure of a single element multicolor detector is presented in this paper. The detector consists of three p-n junction layers of Si, GaSb and InAs wafer bonded to cover the spectral range UV to 900 nm, 800 nm to 1.7 m, and 1.5 m to 3.4 m, respectively. Modeling of the absorption coefficient for each material was carried out for optimizing the layers thicknesses for maximum absorption. The resulted quantum efficiency of each layer has been determined except InAs layer. The optical and electrical characterization of each layer structure is reported including dark current and spectral response measurements of Si pin structure and of GaSb and InAs p-n junctions. The effect of the material processing is discussed.
Abedin, M. Nurul; Refaat, Tamer F.; Bhat, Ishwara; Xiao, Ye-Gao; Bandra, Sumith; Gunapala, Sarath D.
A Prototype Three-Dimensional Position Sensitive CdZnTe Detector Array
A new CdZnTe gamma-ray spectrometer system that employs two layers of modular detector arrays is being developed under the collaboration between the University of Michigan and the Pacific Northwest National Labaratory (PNNL). Each layer can accommodate up to three by three 3-dimensional position sensitive CdZnTe gamma-ray spectrometers. This array system is based on the newly developed VAS_UM/TAT4 ASIC readout electronics. Each of the nine detector modules consists of a pixellated CdZnTe detector and a VAS_UM/TAT4 ASIC frontend board. Each 1.5�1.5�1.0 cm3 CdZnTe detector employs an array of 11 by 11 pixellated anodes and a planar cathode. The energy depositions and 3-dimensional positions of individual interactions of each incident gamma ray can be obtained from pulse amplitude, location of each pixel anode and the drift time of electrons. Ten detectors were tested individually and half of them achieved resolution of <1.0% FWHM at 662 keV for single-pixel events (~30% of all 662 keV full energy deposition events). Two of them were tested in a simple array to verify that the upgrade to an array system does not sacrifice the performance of individual detectors. Experimental results of individual detectors and a twodetector array system are presented, and possible causes for several worse performing detectors are discussed.
Zhang, Feng; He, Zhong; Seifert, Carolyn E.
Adaptive optics wavefront sensors based on photon-counting detector arrays
NASA Astrophysics Data System (ADS)
For adaptive optics systems, there is a growing demand for wavefront sensors that operate at higher frame rates and with more pixels while maintaining low readout noise. Lincoln Laboratory has been investigating Geiger-mode avalanche photodiode arrays integrated with CMOS readout circuits as a potential solution. This type of sensor counts photons digitally within the pixel, enabling data to be read out at high rates without the penalty of readout noise. After a brief overview of adaptive optics sensor development at Lincoln Laboratory, we will present the status of silicon Geigermode- APD technology along with future plans to improve performance.
Aull, Brian F.; Schuette, Daniel R.; Reich, Robert K.; Johnson, Robert L.
Bi-material resonant infrared thermal detector and array
NASA Astrophysics Data System (ADS)
A resonant infrared thermal sensor with high sensitivity, whose sensing element is a bi-material structure with thermal expansion mismatch effect, is presented in this paper. The sensor detects infrared radiation by means of tracking the change in resonance frequency of the bi-material structure with temperature change attributed to the infrared radiation from targets. The bi-material structure can amplify the change in resonance frequency compared to a single material sensing structure. In accordance with the theory of vibration mechanics and design principle of infrared thermal detector, the bi-material resonant sensor by means of which an array can be achieved is designed. The simulation results, by ANSYS software analysis based on multi-layer shell finite element, demonstrate that the dependence of resonance frequency on temperature of the designed sensing structure achieves 1Hz/0.01�C. A microarray with 6�6 resonant infrared sensors is fabricated based on microelectronics processes being compatible with integrated circuit fabrication technology. The frequency variation corresponding to the temperature shift can be obtained by electrical measurement.
Zhang, Xia; Zhang, Dacheng
Synthesis arrangement and parity correction of linear array infrared detector
NASA Astrophysics Data System (ADS)
According to the configuration and technical specification of the detector, which has multiple channels, channels mixing, high speed outputs and separate columns between odd and even, a real time digital processing unit based on the CPLD, FPGA and DSP has been developed to achieve the data synthesis and arrangement function and the parity correction algorithm. A special interface circuit with 4 CPLDs is designed to complete the first synthesis step where the 16 channels of data are combined into 4 channels. The second step is finished in FPGA and ROM address encoder where the 4 channels of data are combined into 1 channel. For output data synchronization, FIFO is adopted to achieve the delay of even channels in the parity correction. Data of odd channels enters the columns synthesis unit without any processing and even channels shall be processed in the columns synthesis unit after entering the FIFO unit first and experiencing the delay process. Thereby the pre-processing before image processing of the linear array thermal imager is accomplished.
Wang, Qun; Hong, Pu; Wang, Bo; Wang, Chensheng
The Design and Performance of the 384: Element Submillimeter Detector Array for SHARC II
NASA Technical Reports Server (NTRS)
We report on the performance of the SHARC II detector, a 12 x 32 array of ion implanted Si pop-up bolometers. This 384 element detector array was built as a prototype for the High Angular Resolution Widefield Camera (HAWC) for the Stratospheric Observatory for Infrared Astronomy (SOFIA). We will discuss the design process, the characterization of the detectors, and the performance of the array in the SHARC II instrument. SHARC II is now a facility instrument on the Caltech Submillimeter Observatory, providing background-limited imaging at 350 and 450 microns.
Moseley, Samuel H.; Allen, Christine; Benford, Dominic; Silverberg, Robert; Staguhn, Johannes; Dowell, Darren; Phillips, Tom
Microreactor and electrochemical detectors fabricated using Si and EPON SU8
An electrochemiluminescence (ECL) detector and a microenzymatic reactor (MER) combining Si and SU-8 technologies are described. Both devices were fabricated using standard processing techniques to produce on-wafer sensor elements, which were composed of a platinum or, alternatively, carbon interdigitated electrode array. The platinum array was resting on top of an Si pn photodiode. After these elements were completed, the entire
E L'Hostis; Ph. E Michel; G. C Fiaccabrino; D. J Strike; N. F de Rooij; M Koudelka-Hep
Method for producing a hybridization of detector array and integrated circuit for readout
NASA Technical Reports Server (NTRS)
A process is explained for fabricating a detector array in a layer of semiconductor material on one substrate and an integrated readout circuit in a layer of semiconductor material on a separate substrate in order to select semiconductor material for optimum performance of each structure, such as GaAs for the detector array and Si for the integrated readout circuit. The detector array layer is lifted off its substrate, laminated on the metallized surface on the integrated surface, etched with reticulating channels to the surface of the integrated circuit, and provided with interconnections between the detector array pixels and the integrated readout circuit through the channels. The adhesive material for the lamination is selected to be chemically stable to provide electrical and thermal insulation and to provide stress release between the two structures fabricated in semiconductor materials that may have different coefficients of thermal expansion.
Fossum, Eric R. (inventor); Grunthaner, Frank J. (inventor)
Evaluation of selected detector arrays for space applications
NASA Technical Reports Server (NTRS)
The development of a high density Schottky barrier Infrared Charged Coupled Device (IRCCD) type image sensor for earth observation was initiated. A dual band 512 pixel linear array was developed, which was capable of being butted end to end to make an arbitrarily long linear array. Measurement made on palladium silicide IRCCDs that were two-dimensional 63 x 32 pixel arrays were summarized. The test data on a 512 pixel linear array is also summarized.
Lowrance, J. L.
I-V and noise performance in MWIR to VLWIR large area Hg1-xCdxTe photodiodes
NASA Astrophysics Data System (ADS)
The National Polar-orbiting Operational Environmental Satellite System (NPOESS), is overseen by the Integrated Program Office (IPO), a joint effort of the Department of Defense, Department of Commerce and NASA. One of the instruments on the NPOESS satellite is the Cross-track Infrared Sounder (CrIS) instrument. CrIS is a Fourier Transform interferometric infrared (FTIR) sensor used to measure earth radiance at high spectral resolution to derive pressure, temperature, and moisture profiles of the atmosphere from the ground on up. Each CrIS instrument contains three different cutoff wavelength (?c)focal plane modules (FPMs): an SWIR FPM [?c(98 K) ~ 5 mm], MWIR FPM [?c(98 K) ~ 9 mm] and a LWIR FPM [?c(81 K) ~ 15.5 mm]. There are nine large (850 mm diameter) photodiodes per FPM, the nine detectors being arranged in a 3 x 3 array. The nine detectors are placed under tight tolerances in the X, Y, and Z dimensions. The steps involved in the transfer of photodiodes as part of a newly fabricated wafer to the mounting of the photodiodes on the FPM involves many processing steps including a significant amount of dicing, cleaning, wire bonding and baking at elevated temperatures. Quantum efficiency and 1/f noise in Hg1-xCdxTe photodiodes are critical parameters that limit the sensitivity of infrared sounders. The ratio ?, defined as the noise current in unit bandwidth in(f = 1 Hz, Vd, ?f = 1 Hz) to the dark current Id(Vd), that is, ? = in/Id is one of the parameters used to select photodiodes for placement in FPMs. ? is equivalent to ??H/N that appears in the well-known Hooge expression. For the sixty-one, ?c ~ 9 ?m photodiodes measured at 60 mV reverse bias and at 98 K, the average value of ?dark = 1.3 x 10-4 in the dark and ?PHOTO = in/IPHOTO is ~ 2 x 10-6 under illuminated conditions. These values of ? are a factor of two lower than that reported previously. The ?c ~ 15.5 ?m photodiodes have average ?dark = 1.3 x 10-5 with the highest performance, diffusion current limited photodiodes having values of ?dark in the mid 10-6 range. All of the 850 ?m diameter, ?c ~ 15.5 ?m photodiodes measured have excess low frequency noise, with the best performers having in(f = 100 Hz, Vd =-60 mV , ?f = 1 Hz) ~ 2 x 10-11 A/Hz1/2 and the best photodiode ?dark = 3.92 x 10-6. I-V measurements, noise, and visual inspections are performed at several steps in the photodiodes manufacturing process. It was observed, following FPM fabrication, photodiode dark current and noise had increased from the initial pre-mounting leadless chip carrier (LCC) measurements for some of the nine photodiodes. The performance degradation observed led to an investigation into the cause (baking at elevated temperatures, mechanical handling, electrical stress etc.) of photodiode degradation that occurred between LCC and FPM testing. Correlations between I-V, noise and surface visual defects have been performed on some ?c ~ 15.5 mm photodiodes. This paper outlines the results of the study, correlating the electrical performance observed to visual defects on the surface and to defects seen following cross sectioning of degraded photodiodes. In addition, other lessons learned and the corrective actions implemented that led to the successful manufacture of SWIR, MWIR and LWIR large photodiodes from the material growth to insertion into and successful demonstration of flight FPMs for the CrIS program are described.
D'Souza, A. I.; Stapelbroek, M. G.; Dolan, P. N.; Wijewarnasuriya, P. S.; Boehmer, E.; Smith, D. S.; Ehlert, J. C.; Andrews, J. E.
A charged particle detector array for detection of light charged particles from nuclear reactions
NASA Astrophysics Data System (ADS)
A 4? charged particle detector array (CPDA), for detecting low-Z charged particles from nuclear reactions, was built to improve selection of fusion evaporation channels for in-beam gamma spectroscopy measurements at Inter University Accelerator Centre, New Delhi. The array consists of fourteen fast-slow plastic phoswich detectors coupled to photomultiplier tubes through indigenously developed optical light guides. This paper describes design of optical light guide, target chamber, front-end electronics and presents in-beam performance of the array. Custom made analogue electronic device enables online selection of nuclear reaction channel. The charged particle detection efficiency and improvement in peak to background ratio obtained using CPDA in conjunction with a gamma-detector array demonstrates its usefulness in selection of specific nuclear reaction channel. This array has been used in a number of nuclear spectroscopic and reaction investigations.
Muralithar, S.; Mukherjee, B.; Singh, R. P.; Mukherjee, G.; Joshi, P.; Punithan, A.; Sahu, B. K.; Gupta, A.; Ahuja, R.; Ram, R.; Rao, S.; Saini, S. K.; Zacharis, J.; Bhowmik, R. K.
Enhancement of concentration range of chromatographically detectable components with array detector mass spectrometry
Methods and instruments for high dynamic range analysis of sample components are described. A sample is subjected to time-dependent separation, ionized, and the ions dispersed with a constant integration time across an array of detectors according to the ions m/z values. Each of the detectors in the array has a dynamically adjustable gain or a logarithmic response function, producing an instrument capable of detecting a ratio of responses or 4 or more orders of magnitude.
Enke, Christie
Studies on the fabrication method for the array of polycrystalline mercuric iodide detectors
NASA Astrophysics Data System (ADS)
The Mercuric Iodide (HgI2) semiconductor array detectors possess the characters of low noise, high detection efficiency, high energy resolution and working in room temperature. In this work, modified hot-wall physical vapor deposition (HW-PVD) method was used to grow high-quality polycrystalline HgI2 thin-films on ITO glasses, and then 4�4 and 8�8 HgI2 array detectors for X-ray radiation were fabricated. We used two fabrication processes for polycrystalline HgI2 array detectors. One was using mask made of stainless steel with good flexibility; while the other was to photo lithography the array on the ITO glass. The main purpose for this work was to compare the electrical properties of polycrystalline HgI2 array detectors fabricated from different processes, and to find out the optimal process for HgI2 detectors. Results indicated that the photo lithography method was a better way to fabricate polycrystalline mercuric iodide array detector than using mask method.
Zheng, Wei-feng; Shi, Wei-min; Li, Dong-mei; Qin, Juan; Wang, Lin-jun; Huang, Jian; Yu, Jun-yang; Xia, Yi-ben
Observation of high energy atmospheric neutrinos with the Antarctic muon and neutrino detector array
The Antarctic muon and neutrino detector array (AMANDA) began collecting data with ten strings in 1997. Results from the first year of operation are presented. Neutrinos coming through the Earth from the Northern Hemisphere are identified by secondary muons moving upward through the array. Cosmic rays in the atmosphere generate a background of downward moving muons, which are about 106
J. Ahrens; E. Andr�s; X. Bai; G. Barouch; S. W. Barwick; R. C. Bay; T. Becka; K.-H. Becker; D. Bertrand; F. Binon; A. Biron; J. Booth; O. Botner; A. Bouchta; O. Bouhali; M. M. Boyce; S. Carius; A. Chen; D. Chirkin; J. Conrad; J. Cooley; C. G. S. Costa; D. F. Cowen; E. Dalberg; C. de Clercq; T. De Young; P. Desiati; J.-P. Dewulf; P. Doksus; J. Edsj�; P. Ekstr�m; T. Feser; J.-M. Fr�re; T. K. Gaisser; M. Gaug; A. Goldschmidt; A. Hallgren; F. Halzen; K. Hanson; R. Hardtke; T. Hauschildt; M. Hellwig; H. Heukenkamp; G. C. Hill; P. O. Hulth; S. Hundertmark; J. Jacobsen; A. Karle; J. Kim; B. Koci; L. K�pke; M. Kowalski; J. I. Lamoureux; H. Leich; M. Leuthold; P. Lindahl; I. Liubarsky; P. Loaiza; D. M. Lowder; J. Madsen; P. Marciniewski; H. S. Matis; C. P. McParland; T. C. Miller; Y. Minaeva; P. Miocinovic; P. C. Mock; R. Morse; T. Neunh�ffer; P. Niessen; D. R. Nygren; H. �gelman; Ph. Olbrechts; C. P�rez de Los Heros; A. C. Pohl; R. Porrata; P. B. Price; G. T. Przybylski; K. Rawlins; C. Reed; W. Rhode; M. Ribordy; S. Richter; J. Rodr�guez Martino; P. Romenesko; D. Ross; H.-G. Sander; T. Schmidt; D. Schneider; R. Schwarz; A. Silvestri; M. Solarz; G. M. Spiczak; C. Spiering; N. Starinsky; D. Steele; P. Steffen; R. G. Stokstad; O. Streicher; P. Sudhoff; K.-H. Sulanke; I. Taboada; L. Thollander; T. Thon; S. Tilav; M. Vander Donckt; C. Walck; C. Weinheimer; C. H. Wiebusch; C. Wiedeman; R. Wischnewski; H. Wissing; K. Woschnagg; W. Wu; G. Yodh; S. Young
The FPGA Pixel Array Detector Marianne S. Hromalik a,b,n
The FPGA Pixel Array Detector Marianne S. Hromalik a,b,n , Katherine S. Green b , Hugh T. Philipp b field programmable gate array (FPGA) into a 3-layer device along with a high-resistivity diode detection an energy-discriminating photon-counting front end with photon hits streamed directly to the FPGA via
Gruner, Sol M.
Design of Light Pipe for an Active Target in the Blowfish Detector Array
Design of Light Pipe for an Active Target in the Blowfish Detector Array Michael Barnett Jennifer of Saskatchewan August 30, 2004 1 Introduction This report outlines the development of a light pipe for an active target in the Blowfish array at the High Energy Gamma Source at Duke University. The light pipe
Saskatchewan, University of
Modulation Transfer Function (MTF) measurement techniques for lenses and linear detector arrays
NASA Technical Reports Server (NTRS)
Application is the determination of the Modulation Transfer Function (MTF) for linear detector arrays. A system set up requires knowledge of the MTF of the imaging lens. Procedure for this measurement is described for standard optical lab equipment. Given this information, various possible approaches to MTF measurement for linear arrays is described. The knife edge method is then described in detail.
Schnabel, J. J., Jr.; Kaishoven, J. E., Jr.; Tom, D.
Observation of high energy atmospheric neutrinos with the Antarctic muon and neutrino detector array
Observation of high energy atmospheric neutrinos with the Antarctic muon and neutrino detector. Rawlins,11 C. Reed,8,§§ W. Rhode,2 M. Ribordy,4 S. Richter,11 J. Rodri´guez Martino,14 P. Romenesko,11 D; published 31 July 2002 The Antarctic muon and neutrino detector array AMANDA began collecting data with ten
Woschnagg, Kurt
Observation of high energy atmospheric neutrinos with the Antarctic muon and neutrino detector array
Observation of high energy atmospheric neutrinos with the Antarctic muon and neutrino detector. Rawlins, 11 C. Reed, 8,§§ W. Rhode, 2 M. Ribordy, 4 S. Richter, 11 J. Rodr� �?? guez Martino, 14 P and neutrino detector array #AMANDA# began collecting data with ten strings in 1997. Results from the first
Woschnagg, Kurt
A multilayer detector for PET based on APD arrays and continuous crystal elements
Scintillation detectors developed for PET traditionally uses relatively thick crystals (to ensure good efficiency), which are coupled to photomultiplier tubes. The crystals typically measure between 10 and 30mm thick. Detectors also require good spatial resolution so the scintillator is normally made up of a densely packed array of long thin crystals. In our design the detection crystal is divided into
Stephen McCallum; Peter Clowes; Andrew Welch
A PCI Based Data Acquisition System for Ground Array Detectors with Wireless Synchronization through GPS
The synchronization of ground based cosmic ray detectors is a recurring problem. Traditional acquisition systems usually drive signal cables from each station of an array of detectors to a central acquisition system. In the context of ULTRA, a support experiment for the EUSO mission, a distributed wireless acquisition system based on a PCI board with synchronization through GPS was developed.
P. Assis; P. Brogueira; L. Melo; M. Pimenta; J. C. Silva; J. Varela
Chemical imaging of cotton fibers using an infrared microscope and a focal-plane array detector
Technology Transfer Automated Retrieval System (TEKTRAN)
In this presentation, the chemical imaging of cotton fibers with an infrared microscope and a Focal-Plane Array (FPA) detector will be discussed. Infrared spectroscopy can provide us with information on the structure and quality of cotton fibers. In addition, FPA detectors allow for simultaneous spe...
Cimicifuga species identification by high performance liquid chromatography�photodiode array\\/mass spectrometric\\/evaporative light scattering detection for quality control of black cohosh products
Black cohosh has become one of the most important herbal products in the US dietary supplements market. It is manufactured from roots and rhizomes of Cimicifuga racemosa (Ranunculaceae). Botanical identification of the raw starting material is a key step in the quality control of black cohosh preparations. The present report summarizes a fingerprinting approach based on high performance liquid chromatography�photodiode
Kan He; Guido F. Pauli; Bolin Zheng; Huikang Wang; Naisheng Bai; Tangsheng Peng; Marc Roller; Qunyi Zheng
Trigger and aperture of the surface detector array of the Pierre Auger Observatory
The surface detector array of the Pierre Auger Observatory consists of 1600 water-Cherenkov detectors, for the study of extensive air showers (EAS) generated by ultra-high-energy cosmic rays. We describe the trigger hierarchy, from the identification of candidate showers at the level of a single detector, amongst a large background (mainly random single cosmic ray muons), up to the selection of
J. Abraham; P. Abreu; M. Aglietta; E. J. Ahn; D. Allard; I. Allekotte; J. Allen; J. Alvarez-Mu�iz; M. Ambrosio; L. Anchordoqui; S. Andringa; T. Anticic; A. Anzalone; C. Aramo; E. Arganda; K. Arisaka; F. Arqueros; H. Asorey; P. Assis; J. Aublin; G. Avila; T. B�cker; D. Badagnani; M. Balzer; K. B. Barber; A. F. Barbosa; S. L. C. Barroso; B. Baughman; P. Bauleo; J. J. Beatty; B. R. Becker; K. H. Becker; A. Bell�toile; J. A. Bellido; S. Benzvi; C. Berat; T. Bergmann; X. Bertou; P. L. Biermann; P. Billoir; O. Blanch-Bigas; F. Blanco; M. Blanco; H. Bl�mer; M. Boh�cov�; D. Boncioli; C. Bonifazi; R. Bonino; N. Borodai; J. Brack; P. Brogueira; W. C. Brown; R. Bruijn; P. Buchholz; A. Bueno; R. E. Burton; N. G. Busca; K. S. Caballero-Mora; L. Caramete; R. Caruso; A. Castellina; O. Catalano; G. Cataldi; L. Cazon; R. Cester; J. Chauvin; A. Chiavassa; J. A. Chinellato; A. Chou; J. Chudoba; R. W. Clay; E. Colombo; M. R. Coluccia; R. Concei��o; F. Contreras; H. Cook; M. J. Cooper; J. Coppens; A. Cordier; U. Cotti; S. Coutu; C. E. Covault; A. Creusot; A. Criss; J. Cronin; A. Curutiu; S. Dagoret-Campagne; R. Dallier; K. Daumiller; B. R. Dawson; R. M. de Almeida; C. de Donato; S. J. de Jong; G. De La Vega; I. De Mitri; V. de Souza; K. D. de Vries; G. Decerprit; L. del Peral; O. Deligny; A. Della Selva; C. Delle Fratte; H. Dembinski; C. Di Giulio; J. C. Diaz; M. L. D�az Castro; P. N. Diep; C. Dobrigkeit; J. C. D�Olivo; P. N. Dong; A. Dorofeev; J. C. dos Anjos; M. T. Dova; D. D�Urso; I. Dutan; M. A. DuVernois; J. Ebr; R. Engel; M. Erdmann; C. O. Escobar; A. Etchegoyen; P. Facal San Luis; H. Falcke; G. Farrar; A. C. Fauth; N. Fazzini; A. Ferrero; B. Fick; A. Filevich; A. Filipcic; I. Fleck; S. Fliescher; C. E. Fracchiolla; E. D. Fraenkel; U. Fr�hlich; W. Fulgione; R. F. Gamarra; S. Gambetta; B. Garc�a; D. Garc�a G�mez; D. Garcia-Pinto; X. Garrido; G. Gelmini; H. Gemmeke; P. L. Ghia; U. Giaccari; M. Giller; H. Glass; L. M. Goggin; M. S. Gold; G. Golup; F. Gomez Albarracin; M. G�mez Berisso; P. Gon�alves; D. Gonzalez; J. G. Gonzalez; D. G�ra; A. Gorgi; P. Gouffon; S. R. Gozzini; E. Grashorn; S. Grebe; M. Grigat; A. F. Grillo; Y. Guardincerri; F. Guarino; G. P. Guedes; J. D. Hague; V. Halenka; P. Hansen; D. Harari; S. Harmsma; J. L. Harton; A. Haungs; T. Hebbeker; D. Heck; A. E. Herve; C. Hojvat; V. C. Holmes; P. Homola; J. R. H�randel; A. Horneffer; M. Hrabovsk�; T. Huege; M. Hussain; M. Iarlori; A. Insolia; F. Ionita; A. Italiano; S. Jiraskova; K. Kadija; M. Kaducak; K. H. Kampert; T. Karova; P. Kasper; B. K�gl; B. Keilhauer; A. Keivani; J. Kelley; E. Kemp; R. M. Kieckhafer; H. O. Klages; M. Kleifges; J. Kleinfeller; R. Knapik; J. Knapp; D.-H. Koang; A. Krieger; O. Kr�mer; D. Kruppke-Hansen; F. Kuehn; D. Kuempel; K. Kulbartz; N. Kunka; A. Kusenko; G. La Rosa; C. Lachaud; B. L. Lago; P. Lautridou; M. S. A. B. Le�o; D. Lebrun; P. Lebrun; J. Lee; M. A. Leigui de Oliveira; A. Lemiere; A. Letessier-Selvon; I. Lhenry-Yvon; R. L�pez; A. Lopez Ag�era; K. Louedec; J. Lozano Bahilo; A. Lucero; M. Ludwig; H. Lyberis; M. C. Maccarone; C. Macolino; S. Maldera; D. Mandat; P. Mantsch; A. G. Mariazzi; V. Marin; I. C. Maris; H. R. Marquez Falcon; G. Marsella; D. Martello; O. Mart�nez Bravo; H. J. Mathes; J. Matthews; G. Matthiae; D. Maurizio; P. O. Mazur; M. McEwen; G. Medina-Tanco; M. Melissas; D. Melo; E. Menichetti; A. Menshikov; C. Meurer; S. Micanovic; M. I. Micheletti; W. Miller; L. Miramonti; S. Mollerach; M. Monasor; D. Monnier Ragaigne; F. Montanet; B. Morales; C. Morello; E. Moreno; J. C. Moreno; C. Morris; M. Mostaf�; S. Mueller; M. A. Muller; R. Mussa; G. Navarra; J. L. Navarro; S. Navas; P. Necesal; L. Nellen; P. T. Nhung; N. Nierstenhoefer; D. Nitz; D. Nosek; L. Nozka; M. Nyklicek; J. Oehlschl�ger; A. Olinto; P. Oliva; V. M. Olmos-Gilbaja; M. Ortiz; N. Pacheco; D. Pakk Selmi-Dei; M. Palatka; J. Pallotta; N. Palmieri; G. Parente; E. Parizot; S. Parlati; A. Parra; J. Parrisius; R. D. Parsons; S. Pastor; T. Paul; V. Pavlidou; K. Payet; M. Pech; R. Pelayo; I. M. Pepe; L. Perrone; R. Pesce; E. Petermann; S. Petrera; P. Petrinca; A. Petrolini; Y. Petrov; J. Petrovic; C. Pfendner; R. Piegaia; T. Pierog; M. Pimenta; V. Pirronello; M. Platino; V. H. Ponce; M. Pontz; P. Privitera; M. Prouza; E. J. Quel; J. Rautenberg; O. Ravel; D. Ravignani; A. Redondo; B. Revenu; F. A. S. Rezende; J. Ridky; S. Riggi; M. Risse; P. Ristori; C. Rivi�re; V. Rizi; C. Robledo; G. Rodriguez; J. Rodriguez Martino; J. Rodriguez Rojo; I. Rodriguez-Cabo; M. D. Rodr�guez-Fr�as; G. Ros; J. Rosado; T. Rossler; M. Roth; B. Rouill�-d�Orfeuil; E. Roulet; A. C. Rovero; F. Salamida; H. Salazar; G. Salina; F. S�nchez; M. Santander; C. E. Santo; E. Santo; E. M. Santos; F. Sarazin; S. Sarkar; R. Sato; N. Scharf; V. Scherini; H. Schieler; P. Schiffer; A. Schmidt; F. Schmidt
Majorana: An Ultra-Low Background Enriched-Germanium Detector Array for Fundamental Physics Measurements
The Majorana collaboration will search for neutrinoless double-beta decay (0nubetabeta) by fielding an array of high-purity germanium (HPGe) detectors in ultra-clean electroformed-copper cryostats deep underground. Recent advances in HPGe detector technology, in particular P-type Point-Contact (PPC) detectors, present exciting new techniques for identifying and reducing backgrounds to the 0nubetabeta. This should result in greatly improved sensitivity over previous generation experiments.
Michael Miller
MAJORANA: An Ultra-Low Background Enriched-Germanium Detector Array for Fundamental Physics Measurements
The Majorana collaboration aims to perform a search for neutrinoless double-beta decay (0nubetabeta) by fielding arrays of HPGe detectors mounted in ultra-clean electroformed-copper cryostats located deep underground. Recent advances in HPGe detector technology, in particular P-type Point-Contact (PPC) detectors, show great promise for identifying and reducing backgrounds to the 0nubetabeta signal, which should result in improved sensitivity over previous generation
Jason Detwiler
Integrated filter and detector array for spectral imaging
NASA Technical Reports Server (NTRS)
A spectral imaging system having an integrated filter and photodetector array is disclosed. The filter has narrow transmission bands which vary in frequency along the photodetector array. The frequency variation of the transmission bands is matched to, and aligned with, the frequency variation of a received spectral image. The filter is deposited directly on the photodetector array by a low temperature deposition process. By depositing the filter directly on the photodetector array, permanent alignment is achieved for all temperatures, spectral crosstalk is substantially eliminated, and a high signal to noise ratio is achieved.
Labaw, Clayton C. (inventor)
Optimal heterodyne detector array size for 1-microm coherent lidar propagation through atmospheric turbulence.
The heterodyne detection efficiency for a 1-microm coherent atmospheric backscatter lidar was numerically calculated using a Monte Carlo technique which included a simple model for the effects of atmospheric turbulence. The results show that the heterodyne detection efficiency of a single-element detector is severely reduced by the effects of atmospheric turbulence, but that the use of an appropriate sized, multiple-element heterodyne detector array can overcome these effects. In addition, the statistical fluctuation (signal-to-noise ratio) of the lidar signal was also calculated and showed that the use of a heterodyne detector array can increase the accuracy to that for direct detection. PMID:20700250
Sugimoto, N; Chan, K P; Killinger, D K
Extending the Astronomical Application of Photon Counting HgCdTe Linear Avalanche Photo-Diode Arrays to Low Background Space Observations.
NASA Astrophysics Data System (ADS)
The high quantum efficiency and very low dark current, together with the ability to set the wavelength cutoff from one to far beyond 5.5 microns, of large format HAWAII HgCdTe arrays have already made them the workhorse for NASA space astronomy (and related) observations in the 1 to 5.5 micron infrared. They have performed outstandingly on Hubble Wide Field Camera 3 and WISE (and also Deep Impact/EPOXI and OCO-2) and are crucial to the two major NASA Astrophysics missions, JWST and WFIRST, and to Euclid. The proposed investigation seeks to extend these benefits to the most demanding observations those that seek to wring information from only a few photons (starved due to either the intrinsic faintness of the source or the need for high spectral or time resolution) or to discriminate a weak signature against a bright source. We will characterize, and optimize for space astronomy observations, the unique linear avalanche properties of HgCdTe photo-diodes (HgCdTe L-APDs) that allow noiseless (i.e. faithfully preserves the Poisson statistics of the incoming photons) avalanche multiplication of individual photo-electrons. 2.5 micron HgCdTe L-APD technology, developed for infrared eye-safe LIDAR and range gated imaging, is already benefiting infrared wavefront sensing for ground based adaptive optics. In HgCdTe the L-APD gain and the onset voltage for tunneling current are exponential functions of bandgap while also varying with cryogenic operating temperature. The unique HgCdTe bandgap engineering that allows tuning of the cutoff wavelength can be used to critically improve avalanche performance for specific applications. We will thoroughly evaluate avalanche performance at several representative bandgaps so as to allow model prediction of performance over the critical 1 to 5 micron spectral interval. The proposed investigation will hybridize modest 32x32 arrays of HgCdTe L-APDs to photon counting readouts already developed under another award and characterize their infrared photon counting performance at the low and ultra-low backgrounds required for NASA space astronomy missions. Specifically this will involve 1) Measuring the gain normalized dark count rate and avalanche gain of 2.5, 3.3 and 4 micron cutoff HgCdTe at cryogenic temperatures from 30 to 80 K and bias voltages up to 20 V, 2) Using these results to validate and refine models of avalanche gain along with generation- recombination and surface trap induced tunneling current in L-APD HgCdTe and, 3) Modeling the gain normalized dark count rate, surface tunneling current and avalanche gain of 2 to 5 micron cutoff HgCdTe L-APD arrays for astrophysics and other NASA missions. The overall objective of the investigation is to develop the tools to identify the sweet spot in bandgap and cryogenic operating temperature for each specific NASA astrophysics mission and to accurately predict ultimate performance. HgCdTe L-APD technology offers to NASA the ultimate performance for space astronomy in photon starved applications such as: 1) ultra-low background, extra- Zodiacal imaging and faint object spectroscopy from elliptical orbits beyond the asteroid belt with missions such as Extra-Zodiacal Explorer, 2) spectroscopy of the faintest O/IR sources from near earth and L-2 orbit at moderate to high resolution and, 3) time domain astronomy observations (photometric or spectral variations at frequencies above 1 Hz) of sources as diverse as close binaries, accretion disks, compact objects etc. HgCdTe L- APD arrays have the potential to enable new classes of missions and to bring critical observations within reach of the capabilities of the NASA SMD Astrophysics Explorer program. As they utilize the same mature TRL base as the large format JWST HgCdTe arrays, requiring only qualification of n-on-p material operated at higher bias voltages, the path to flight qualification is unusually direct.
Hall, Donald
Development of uncooled focal plane detector arrays for smart IR sensors
NASA Astrophysics Data System (ADS)
This paper reports on the development of silicon microbolometer uncooled IR focal plane detector arrays at the Defence Science and Technology Organization (DSTO), in collaboration with the National Defence Research Establishment (FOA). The detector arrays were designed by Electro-optic Sensor Design, which also provided specialist scientific advice on array fabrication. Detector arrays are prepared by monolithic processing at DSTO, using surface micromachining to achieve thermal isolation, and are integrated on-chip with a CMOS signal conditioning and readout microcircuit designed by FOA. The CMOS circuit incorporates 16-bit analog-to-digital conversion, and is described in more detail in an accompanying paper presented. The ultimate objective is to develop 'smart' focal plane arrays which have on-chip signal processing functions, giving a capability for decision making such as automatic target detection. The silicon microbolometer technology described in the paper was invented at DSTO, and is representative of core technology employed in many initiatives world-wide. A brief overview will be given of theoretical considerations which influence detector array design, followed by an outline of recent developments in array processing.
Liddiard, Kevin C.; Reinhold, Olaf; Ringh, Ulf; Jansson, Christer
Trigger and Aperture of the Surface Detector Array of the Pierre Auger Observatory
The surface detector array of the Pierre Auger Observatory consists of 1600 water-Cherenkov detectors, for the study of extensive air showers (EAS) generated by ultra-high-energy cosmic rays. We describe the trigger hierarchy, from the identification of candidate showers at the level of a single detector, amongst a large background (mainly random single cosmic ray muons), up to the selection of real events and the rejection of random coincidences. Such trigger makes the surface detector array fully efficient for the detection of EAS with energy above $3\\times 10^{18}$ eV, for all zenith angles between 0$^\\circ$ and 60$^\\circ$, independently of the position of the impact point and of the mass of the primary particle. In these range of energies and angles, the exposure of the surface array can be determined purely on the basis of the geometrical acceptance.
Abraham, J; Aglietta, M; Aguirre, C; Ahn, E J; Allard, D; Allekotte, I; Allen, J; Alvarez-Mu�iz, J; Ambrosio, M; Anchordoqui, L; Andringa, S; Anzalone, A; Aramo, C; Arganda, E; Argir�, S; Arisaka, K; Arneodo, F; Arqueros, F; Asch, T; Asorey, H; Assis, P; Aublin, J; Ave, M; Avila, G; B�cker, T; Badagnani, D; Barber, K B; Barbosa, A F; Barroso, S L C; Baughman, B; Bauleo, P; Beatty, J J; Beau, T; Becker, B R; Becker, K H; Bell�toile, A; Bellido, J A; BenZvi, S; Berat, C; Bernardini, P; Bertou, X; Biermann, P L; Billoir, P; Blanch-Bigas, O; Blanco, F; Bleve, C; Bl�mer, H; Boh�?ov�, M; Boncioli, D; Bonifazi, C; Bonino, R; Borodai, N; Brack, J; Brogueira, P; Brown, W C; Bruijn, R; Buchholz, P; Bueno, A; Burton, R E; Busca, N G; Caballero-Mora, K S; Caramete, L; Caruso, R; Carvalho, W; Castellina, A; Catalano, O; Cazon, L; Cester, R; Chauvin, J; Chiavassa, A; Chinellato, J A; Chou, A; Chudoba, J; Chye, J; Clay, R W; Colombo, E; Concei��o, R; Connolly, B; Contreras, F; Coppens, J; Cordier, A; Cotti, U; Coutu, S; Covault, C E; Creusot, A; Criss, A; Cronin, J; Curutiu, A; Dagoret-Campagne, S; Dallier, R; Daumiller, K; Dawson, B R; de Almeida, R M; De Domenico, M; De Donato, C; de Jong, S J; De La Vega, G; Junior, W J M de Mello; Neto, J R T de Mello; De Mitri, I; de Souza, V; de Vries, K D; Decerprit, G; del Peral, L; Deligny, O; Della Selva, A; Fratte, C Delle; Dembinski, H; Di Giulio, C; Diaz, J C; Diep, P N; Dobrigkeit, C; D'Olivo, J C; Dong, P N; Dorofeev, A; Anjos, J C dos; Dova, M T; D'Urso, D; Dutan, I; DuVernois, M A; Engel, R; Erdmann, M; Escobar, C O; Etchegoyen, A; Luis, P Facal San; Falcke, H; Farrar, G; Fauth, A C; Fazzini, N; Ferrer, F; Ferrero, A; Fick, B; Filevich, A; Filip?i?, A; Fleck, I; Fliescher, S; Fracchiolla, C E; Fraenkel, E D; Fulgione, W; Gamarra, R F; Gambetta, S; Garc�a, B; G�mez, D Garc�a; Garcia-Pinto, D; Garrido, X; Gelmini, G; Gemmeke, H; Ghia, P L; Giaccari, U; Giller, M; Glass, H; Goggin, L M; Gold, M S; Golup, G; Albarracin, F Gomez; Berisso, M G�mez; Gon�alves, P; Amaral, M Gon�alves do; Gonzalez, D; Gonzalez, J G; G�ra, D; Gorgi, A; Gouffon, P; Gozzini, S R; Grashorn, E; Grebe, S; Grigat, M; Grillo, A F; Guardincerri, Y; Guarino, F; Guedes, G P; Guti�rrez, J; Hague, J D; Halenka, V; Hansen, P; Harari, D; Harmsma, S; Harton, J L; Haungs, A; Healy, M D; Hebbeker, T; Hebrero, G; Heck, D; Hojvat, C; Holmes, V C; Homola, P; H�randel, J R; Horneffer, A; Hrabovsk�, M; Huege, T; Hussain, M; Iarlori, M; Insolia, A; Ionita, F; Italiano, A; Jiraskova, S; Kaducak, M; Kampert, K H; Karova, T; Kasper, P; K�gl, B; Keilhauer, B; Kemp, E; Kieckhafer, R M; Klages, H O; Kleifges, M; Kleinfeller, J; Knapik, R; Knapp, J; Koang, D -H; Krieger, A; Kr�mer, O; Kruppke-Hansen, D; Kuehn, F; Kuempel, D; Kulbartz, K; Kunka, N; Kusenko, A; La Rosa, G; Lachaud, C; Lago, B L; Lautridou, P; Le�o, M S A B; Lebrun, D; Lebrun, P; Lee, J; de Oliveira, M A Leigui; Lemiere, A; Letessier-Selvon, A; Leuthold, M; Lhenry-Yvon, I; L�pez, R; Ag�era, A Lopez; Louedec, K; Bahilo, J Lozano; Lucero, A; Lyberis, H; Maccarone, M C; Macolino, C; Maldera, S; Mandat, D; Mantsch, P; Mariazzi, A G; Maris, I C; Falcon, H R Marquez; Martello, D; Bravo, O Mart�nez; Mathes, H J; Matthews, J; Matthews, J A J; Matthiae, G; Maurizio, D; Mazur, P O; McEwen, M; McNeil, R R; Medina-Tanco, G; Melissas, M; Melo, D; Menichetti, E; Menshikov, A; Meyhandan, R; Micheletti, M I; Miele, G; Miller, W; Miramonti, L; Mollerach, S; Monasor, M; Ragaigne, D Monnier; Montanet, F; Morales, B; Morello, C; Moreno, J C; Morris, C; Mostaf�, M; Moura, C A; Mueller, S; Muller, M A; Mussa, R; Navarra, G; Navarro, J L; Navas, S; Necesal, P; Nellen, L; Newman-Holmes, C; Newton, D; Nhung, P T; Nierstenhoefer, N; Nitz, D; Nosek, D; No�ka, L; Nyklicek, M; Oehlschl�ger, J; Olinto, A; Oliva, P; Olmos-Gilbaja, V M; Ortiz, M; Pacheco, N; Selmi-Dei, D Pakk; Palatka, M; Pallotta, J; Parente, G; Parizot, E; Parlati, S; Pastor, S; Patel, M; Paul, T; Pavlidou, V; Payet, K; Pech, M; P?kala, J; Pepe, I M; Perrone, L; Pesce, R; Petermann, E; Petrera, S; Petrinca, P; Petrolini, A; Petrov, Y; Petrovic, J; Pfendner, C; Piegaia, R; Pierog, T; Pimenta, M; Pinto, T; Pirronello, V; Pisanti, O; Platino, M; Pochon, J; Ponce, V H; Pontz, M; Privitera, P; Prouza, M; Quel, E J; Rautenberg, J; Ravel, O; Ravignani, D; Redondo, A; Revenu, B; Rezende, F A S; Ridky, J; Riggi, S; Risse, M; Rivi�re, C; Rizi, V; Robledo, C; Rodriguez, G; Martino, J Rodriguez; Rojo, J Rodriguez; Rodriguez-Cabo, I; Rodr�guez-Fr�as, M D; Ros, G; Rosado, J; Rossler, T; Roth, M; Rouill�-d'Orfeuil, B; Roulet, E; Rovero, A C; Salamida, F; Salazar, H; Salina, G; S�nchez, F; Santander, M; Santo, C E; Santos, E M; Sarazin, F; Sarkar, S; Sato, R; Scharf, N; Scherini, V; Schieler, H; Schiffer, P; Schmidt, A; Schmidt, F; Schmidt, T
Electronics for the Extensive Air Shower Detector Array at the University of Puebla
NASA Astrophysics Data System (ADS)
In this paper we describe in detail the electronics cards that were designed to be the basis of the data acquisition system (DAS) of the extensive air shower detector array built in the Campus of the University of Puebla. The purpose of this observatory is to measure the energy and arrival direction of primary cosmic rays with energies around 1015 eV. The array consists of 18 liquid scintillator detectors (12 in the first stage) and 6 water Cherenkov detectors (one of 10 m2 cross section and five smaller ones of 1.86 m2 cross section), distributed in a square grid with a detector spacing of 20 m over an area of 4000 m2. The electronics described here uses analog to digital converters of 10 bits working at a sampling speed of 40 MS/s and field-programmable gate array (FPGA).
P�rez, E.; Conde, R.; Mart�nez, O.; Murrieta, T.; Salazar, H.; Villase�or, L.
A cooled avalanche photodiode with high photon detection probability
NASA Technical Reports Server (NTRS)
An avalanche photodiode has been operated as a photon-counting detector with 2 to 3 times the sensitivity of currently-available photomultiplier tubes. APD (avalanche photodiodes) detection probabilities that exceed 27% and approach 50% have been measured at an optimum operating temperature which minimizes noise. The sources of noise and their dependence on operating temperature and bias voltage are discussed.
Robinson, D. L.; Metscher, B. D.
A large underground water Cherenkov muon detector array with the Tibet air shower array for Gamma-ray astronomy in the 100 TeV region: detector design and simulation
We are planning to build a large water-Cherenkov-type muon detector array around the Tibet air shower array for Gamma-ray astronomy in the 100 TeV Region. In this paper, we describe the design of the Tibet MD array and details of the Monte Carlo simulation to demonstrate the sensitivity of the Tibet AS+MD array.
S. Ayabe; X. J. Bi; D. Chen; S. W. Cui; Danzengluobu; L. K. Ding; X. H. Ding; C. F. Feng; Zhaoyang Feng; Z. Y. Feng; X. Y. Gao; Q. X. Geng; H. W. Guo; H. H. He; M. He; K. Hibino; N. Hotta; Haibing Hu; H. B. Hu; J. Huang; Q. Huang; H. Y. Jia; F. Kajino; K. Kasahara; Y. Katayose; C. Kato; K. Kawata; Labaciren; G. M. Le; A. F. Li; J. Y. Li; Y.-Q. Lou; H. Lu; S. L. Lu; X. R. Meng; K. Mizutani; J. Mu; K. Munakata; A. Nagai; H. Nanjo; M. Nishizawa; M. Ohnishi; I. Ohta; H. Onuma; T. Ouchi; S. Ozawa; J. R. Ren; T. Saito; M. Sakata; T. Sasaki; M. Shibata; A. Shiomi; T. Shirai; H. Sugimoto; M. Takita; Y. H. Tan; N. Tateyama; T. K. Sako; S. Torii; H. Tsuchiya; S. Udo; B. Wang; H. Wang; X. Wang; Y. G. Wang; H. R. Wu; L. Xue; Y. Yamamoto; C. T. Yan; X. C. Yang; S. Yasue; Z. H. Ye; G. C. Yu; A. F. Yuan; T. Yuda; H. M. Zhang; J. L. Zhang; N. J. Zhang; X. Y. Zhang; Y. Zhang; Yi Zhang; Zhaxisangzhu; X. X. Zhou
Imaging by time-tagging photons with the multi-anode microchannel array detector system
NASA Technical Reports Server (NTRS)
The capability and initial use of the Multi-Anode Microchannel Array (MAMA) detector in the time-tag mode is reported. The detector hardware currently in use consists of a visible-light detector tube with a semitransparent photocathode proximity-focused to a high-gain curved-channel microchannel plate MCP. The photoevents are detected by a (256 x 1024)-pixel coincidence-anode array with pixel dimensions of 25 x 25 microns connected to charge-sensitive amplifiers and event-detection circuitry. In the time-lag mode, the detector delivers the pixel address and the time of arrival for each detected photon to an accuracy of 10 microns. The maximum count rate is limited by the speed of data-acquisition hardware. The MAMA detector in the time-lag mode is currently being evaluated in programs of astrometry and speckle imaging.
Timothy, J. G.; Morgan, J. S.
Description of the Role of Shot Noise in Spectroscopic Absorption and Emission Measurements with Photodiode and Photomultiplier Tube Detectors: Information for an Instrumental Analysis Course
ERIC Educational Resources Information Center
A description of shot noise and the role it plays in absorption and emission measurements using photodiode and photomultiplier tube detection systems is presented. This description includes derivations of useful forms of the shot noise equation based on Poisson counting statistics. This approach can deepen student understanding of a fundamental�
McClain, Robert L.; Wright, John C.
The development and test of multi-anode microchannel array detector systems. Part 2: Soft X-ray detectors
NASA Technical Reports Server (NTRS)
Multi-Anode Microchannel Array (MAMA) detector systems with formats of 256 x 1024 pixels and active areas of 6 x 26 square mm are now under evaluation at visible, ultraviolet and soft x-ray wavelengths. Very-large-format versions of the MAMA detectors with formats of 2048 x 2048 pixels and active areas of 52 x 52 square mm are under development for use in the NASA Goddard Space Flight Center's Space Telescope Imaging Spectrograph (STIS). Open-structure versions of these detectors with CsI photocathodes can provide a high-resolution imaging capability at extreme ultraviolet (EUV) and soft x-ray wavelengths and can deliver a maximum count rate from each array in excess of 1 million counts s-1. In addition, these detector systems have the unique capability to determine the arrival time of a detected photon to an accuracy of 100 ns or better. The construction, mode-of-operation and performance characteristics of the MAMA detectors are described and the program for the development of the very-large-format detectors is outlined.
Timothy, J. G.
MONSOON image acquisition system: control techniques for application to the orthogonal transfer array detectors
NASA Astrophysics Data System (ADS)
The MONSOON Detector Controller has successfully demonstrated the ability to control the complex image acquisition and real time processing required to achieve quality science performance from the Orthogonal Transfer Array (OTA) detector technology. A mosaic of four OTA detectors has been used to track multiple guide stars and apply charge shift corrections to compensate for real time image motion. The control algorithms required to achieve this have been embedded and distributed within the MONSOON controller to reduce the control loop latency and improve correction efficiency. This paper highlights the flexibility of the MONSOON architecture in supporting the many roles required by applications of scientific detectors.
Moore, Peter; Buchholz, Nick; Hunten, Mark; Sawyer, David
High-resolution pulse-counting array detectors for imaging and spectroscopy at ultraviolet wavelengths
NASA Technical Reports Server (NTRS)
The performance characteristics of multianode microchannel array (MAMA) detector systems which have formats as large as 256 x 1024 pixels and which have application to imaging and spectroscopy at UV wavelengths are evaluated. Sealed and open-structure MAMA detector tubes with opaque CsI photocathodes can determine the arrival time of the detected photon to an accuracy of 100 ns or better. Very large format MAMA detectors with CsI and Cs2Te photocathodes and active areas of 52 x 52 mm (2048 x 2048 pixels) will be used as the UV solar blind detectors for the NASA STIS.
Timothy, J. Gethyn; Bybee, Richard L.
Quantum Well and Quantum Dot Modeling for Advanced Infrared Detectors and Focal Plane Arrays
NASA Technical Reports Server (NTRS)
This viewgraph presentation reviews the modeling of Quantum Well Infrared Detectors (QWIP) and Quantum Dot Infrared Detectors (QDIP) in the development of Focal Plane Arrays (FPA). The QWIP Detector being developed is a dual band detector. It is capable of running on two bands Long-Wave Infrared (LWIR) and Medium Wavelength Infrared (MWIR). The same large-format dual-band FPA technology can be applied to Quantum Dot Infrared Photodetector (QDIP) with no modification, once QDIP exceeds QWIP in single device performance. Details of the devices are reviewed.
Ting, David; Gunapala, S. D.; Bandara, S. V.; Hill, C. J.
Coherent summation of spatially distorted Doppler lidar signals using a two-dimensional heterodyne detector array
NASA Technical Reports Server (NTRS)
We have investigated the improvement in the signal-to-noise ratio for a coherent Doppler lidar through the use of a multi-element heterodyne detector array. Such an array enables the spatial summation of atmospheric refractive turbulence induced speckles, and time varying target speckles. Our recent experiments have shown that the non-coherent summation of the lidar signals from a heterodyne detector array can enhance the heterodyne mixing efficiency and thus the signal-to-noise ratio. In this paper, we expand this work to include the coherent summation of array signals. The digitized heterodyne signals were stored in a personal computer. Fast Fourier transforms were performed on both the non-coherent and coherent summations of the detector array signals. It was found that the coherent summation greatly enhanced the accuracy in the Doppler frequency estimate. A theoretical analysis was performed and indicated good agreement with experimental results. We have also applied these results to the more general lidar applications including atmospheric wind sensing, and have found that in most lidar applications the Doppler frequency estimate is increased through the use of the heterodyne detector array.
Chan, Kin Pui; Killinger, Dennis K.
Semiconductor detectors and focal plane arrays for far-infrared imaging
NASA Astrophysics Data System (ADS)
The detection of far-infrared (far-IR) and sub-mm-wave radiation is resistant to the commonly employed techniques in the neighbouring microwave and IR frequency bands. In this wavelength detection range the use of solid state detectors has been hampered for the reasons of transit time of charge carriers being larger than the time of one oscillation period of radiation. Also the energy of radiation quanta is substantially smaller than the thermal energy at room temperature and even liquid nitrogen temperature. The realization of terahertz (THz) emitters and receivers is a challenge because the frequencies are too high for conventional electronics and the photon energies are too small for classical optics. Development of semiconductor focal plane arrays started in seventies last century and has revolutionized imaging systems in the next decades. This paper presents progress in far-IR and sub-mm-wave semiconductor detector technology of focal plane arrays during the past twenty years. Special attention is given on recent progress in the detector technologies for real-time uncooled THz focal plane arrays such as Schottky barrier arrays, field-effect transistor detectors, and microbolometers. Also cryogenically cooled silicon and germanium extrinsic photoconductor arrays, and semiconductor bolometer arrays are considered.
Rogalski, A.
Performance of high resolution decoding with Multi-Anode Microchannel Array detectors
NASA Technical Reports Server (NTRS)
The Multi-Anode Microchannel Array (MAMA) is a microchannel plate based photon counting detector with applications in ground-based and space-based astronomy. The detector electronics decode the position of each photon event, and the decoding algorithm that associates a given event with the appropriate pixel is determined by the geometry of the anode array. The standard MAMA detector has a spatial resolution set by the anode array of 25 microns, but the MCP pore resolution exceeds this. The performance of a new algorithm that halves the pixel spacing and improves the pixel spatial resolution is described. The new algorithm does not degrade the pulse-pair resolution of the detector and does not require any modifications to the detector tube. Measurements of the detector's response demonstrate that high resolution decoding yields a 60 percent enhancement in spatial resolution. Measurements of the performance of the high resolution algorithm with a 14 micron MAMA detector are also described. The parameters that control high resolution performance are discussed. Results of the application of high resolution decoding to speckle interferometry are presented.
Kasle, David B.; Horch, Elliott P.
Underground water Cherenkov muon detector array with the Tibet air shower array for gamma-ray astronomy in the 100 TeV region
We propose to build a large water-Cherenkov-type muon-detector array (Tibet MD array) around the 37?000�m2 Tibet air shower array (Tibet AS array) already constructed at 4300�m above sea level in Tibet, China. Each muon detector\\u000a is a waterproof concrete pool, 6�m wide 6�m long 1.5�m deep in size, equipped with a 20 inch-in-diameter PMT. The Tibet\\u000a MD array consists of
M. Amenomori; S. Ayabe; X. J. Bi; D. Chen; S. W. Cui; Danzengluobu; L. K. Ding; X. H. Ding; C. F. Feng; Zhaoyang Feng; Z. Y. Feng; X. Y. Gao; Q. X. Geng; H. W. Guo; H. H. He; M. He; K. Hibino; N. Hotta; Haibing Hu; H. B. Hu; J. Huang; Q. Huang; H. Y. Jia; F. Kajino; K. Kasahara; Y. Katayose; C. Kato; K. Kawata; Labaciren; G. M. Le; A. F. Li; J. Y. Li; H. Lu; S. L. Lu; X. R. Meng; K. Mizutani; J. Mu; K. Munakata; A. Nagai; H. Nanjo; M. Nishizawa; M. Ohnishi; I. Ohta; H. Onuma; T. Ouchi; S. Ozawa; J. R. Ren; T. Saito; M. Sakata; T. K. Sako; T. Sasaki; M. Shibata; A. Shiomi; T. Shirai; H. Sugimoto; M. Takita; Y. H. Tan; N. Tateyama; S. Torii; H. Tsuchiya; S. Udo; B. Wang; H. Wang; X. Wang; Y. G. Wang; H. R. Wu; L. Xue; Y. Yamamoto; C. T. Yan; X. C. Yang; S. Yasue; Z. H. Ye; G. C. Yu; A. F. Yuan; T. Yuda; H. M. Zhang; J. L. Zhang; N. J. Zhang; X. Y. Zhang; Y. Zhang; Yi Zhang; Zhaxisangzhu; X. X. Zhou
Underground water Cherenkov muon detector array with the Tibet air shower array for gamma-ray astronomy in the 100 TeV region
\\u000a We propose to build a large water-Cherenkov-type muon-detector array (Tibet MD array) around the 37?000�m2 Tibet air shower array (Tibet AS array) already constructed at 4300�m above sea level in Tibet, China. Each muon detector\\u000a is a waterproof concrete pool, 6�m wide � 6�m long � 1.5�m deep in size, equipped with a 20 inch-in-diameter PMT. The Tibet\\u000a MD array
M. Amenomori; S. Ayabe; X. J. Bi; D. Chen; S. W. Cui; Danzengluobu; L. K. Ding; X. H. Ding; C. F. Feng; Zhaoyang Feng; Z. Y. Feng; X. Y. Gao; Q. X. Geng; H. W. Guo; H. H. He; M. He; K. Hibino; N. Hotta; Haibing Hu; H. B. Hu; J. Huang; Q. Huang; H. Y. Jia; F. Kajino; K. Kasahara; Y. Katayose; C. Kato; K. Kawata; Labaciren; G. M. Le; A. F. Li; J. Y. Li; H. Lu; S. L. Lu; X. R. Meng; K. Mizutani; J. Mu; K. Munakata; A. Nagai; H. Nanjo; M. Nishizawa; M. Ohnishi; I. Ohta; H. Onuma; T. Ouchi; S. Ozawa; J. R. Ren; T. Saito; M. Sakata; T. K. Sako; T. Sasaki; M. Shibata; A. Shiomi; T. Shirai; H. Sugimoto; M. Takita; Y. H. Tan; N. Tateyama; S. Torii; H. Tsuchiya; S. Udo; B. Wang; H. Wang; X. Wang; Y. G. Wang; H. R. Wu; L. Xue; Y. Yamamoto; C. T. Yan; X. C. Yang; S. Yasue; Z. H. Ye; G. C. Yu; A. F. Yuan; T. Yuda; H. M. Zhang; J. L. Zhang; N. J. Zhang; X. Y. Zhang; Y. Zhang; Yi Zhang; Zhaxisangzhu; X. X. Zhou
Development of sensitive long-wave infrared detector arrays for passively cooled space missions
NASA Astrophysics Data System (ADS)
The near-earth object camera (NEOCam) is a proposed infrared space mission designed to discover and characterize most of the potentially hazardous asteroids larger than 140 m in diameter that orbit near the Earth. NASA has funded technology development for NEOCam, including the development of long wavelength infrared detector arrays that will have excellent zodiacal background emission-limited performance at passively cooled focal plane temperatures. Teledyne Imaging Sensors has developed and delivered for test at the University of Rochester the first set of approximately 10 ?m cutoff, 1024�1024 pixel HgCdTe detector arrays. Measurements of these arrays show the development to be extremely promising: noise, dark current, quantum efficiency, and well depth goals have been met by this technology at focal plane temperatures of 35 to 40 K, readily attainable with passive cooling. The next set of arrays to be developed will address changes suggested by the first set of deliverables.
McMurtry, Craig; Lee, Donald; Beletic, James; Chen, Chi-Yi A.; Demers, Richard T.; Dorn, Meghan; Edwall, Dennis; Fazar, Candice Bacon; Forrest, William J.; Liu, Fengchuan; Mainzer, Amanda K.; Pipher, Judith L.; Yulius, Aristo
IR Imaging Using Arrays of SiO2 Micromechanical Detectors
In this letter, we describe the fabrication of an array of bimaterial detectors for infrared (IR) imaging that utilize SiO2 as a structural material. All the substrate material underneath the active area of each detector element was removed. Each detector element incorporates an optical resonant cavity layer in the IR absorbing region of the sensing element. The simplified microfabrication process requires only four photolithographic steps with no wet etching or sacrificial layers. The thermomechanical deflection sensitivity was 7.9 10-3 rad/K which corresponds to a noise equivalent temperature difference (NETD) of 2.9 mK. In the present work the array was used to capture IR images while operating at room temperature and atmospheric pressure and no need for vacuum packaging. The average measured NETD of our IR detector system was approximately 200 mK but some sensing elements exhibited an NETD of 50 mK.
Grbovic, Dragoslav [ORNL; Lavrik, Nickolay V [ORNL; Rajic, Slobodan [ORNL; Datskos, Panos G [ORNL; Hunter, Scott Robert [ORNL
Initial Field Measurements with the Multisensor Airborne Radiation Survey (MARS) High Purity Germanium (HPGe) Detector Array
Abstract: The Multi-sensor Airborne Radiation Survey (MARS) project has developed a new single cryostat detector array design for high purity germanium (HPGe) gamma ray spectrometers that achieves the high detection efficiency required for stand-off detection and actionable characterization of radiological threats. This approach is necessary since a high efficiency HPGe detector can only be built as an array due to limitations in growing large germanium crystals. The system is ruggedized and shock mounted for use in a variety of field applications. This paper reports on results from initial field measurements conducted in a truck and on two different boats.
Fast, James E.; Bonebrake, Christopher A.; Dorow, Kevin E.; Glasgow, Brian D.; Jensen, Jeffrey L.; Morris, Scott J.; Orrell, John L.; Pitts, W. Karl; Rohrer, John S.; Todd, Lindsay C.
3D imaging LADAR with linear array devices: laser, detector and ROIC
NASA Astrophysics Data System (ADS)
This paper introduces the recent development of 3D imaging LADAR (LAser Detection And Ranging) in Mitsubishi Electric Corporation. The system consists of in-house-made key devices which are linear array: the laser, the detector and the ROIC (Read-Out Integrated Circuit). The laser transmitter is the high power and compact planar waveguide array laser at the wavelength of 1.5 micron. The detector array consists of the low excess noise Avalanche Photo Diode (APD) using the InAlAs multiplication layer. The analog ROIC array, which is fabricated in the SiGe- BiCMOS process, includes the Trans-Impedance Amplifiers (TIA), the peak intensity detectors, the Time-Of-Flight (TOF) detectors, and the multiplexers for read-out. This device has the feature in its detection ability for the small signal by optimizing the peak intensity detection circuit. By combining these devices with the one dimensional fast scanner, the real-time 3D range image can be obtained. After the explanations about the key devices, some 3D imaging results are demonstrated using the single element key devices. The imaging using the developed array devices is planned in the near future.
Kameyama, Shumpei; Imaki, Masaharu; Tamagawa, Yasuhisa; Akino, Yosuke; Hirai, Akihito; Ishimura, Eitaro; Hirano, Yoshihito
Measuring the ultra-high energy comic ray flux with the Telescope Array Middle Drum detector
NASA Astrophysics Data System (ADS)
The Telescope Array (TA) Experiment, located 200 kilometers southwest of Salt Lake City, Utah, is the largest Ultra-High Energy cosmic ray detector in the northern hemisphere. TA is a follow up to the High Resolution Fly's Eye (HiRes) and AGASA experiments, and seeks to gain insight into cosmic ray acceleration by measuring the flux of cosmic rays with energies over 10^18 eV. The detector consists of 507 scintillator counters distributed in a square grid with 1.2 km spacing. Three fluorescence detector stations sit on the corners of a 30 km equilateral triangle overlooking the array of surface detectors, and provide full hybrid coverage with the scintillator array above 10 EeV. Telescope Array underwent commissioning in 2007 and began routine data collection operations at the beginning of 2008. One of the three fluorescence stations, the Middle Drum (MD) site, is instrumented with detectors previously used at the HiRes-1 site. The inclusion of the MD site makes possible a direct comparison between the fluorescence energy scales and spectra between TA and HiRes. We will present a progress report on the analysis of the TA data collected by the MD site.
Sonley, Thomas
A sub-millimeter resolution PET detector module using a multi-pixel photon counter array
A PET block detector module using an array of sub-millimeter lutetium oxyorthosilicate (LSO) crystals read out by an array of surface-mount, semiconductor photosensors has been developed. The detector consists of a LSO array, a custom acrylic light guide, a 3 � 3 multi-pixel photon counter (MPPC) array (S10362-11-050P, Hamamatsu Photonics, Japan) and a readout board with a charge division resistor network. The LSO array consists of 100 crystals, each measuring 0.8 � 0.8 � 3 mm3 and arranged in 0.86 mm pitches. A Monte Carlo simulation was used to aid the design and fabrication of a custom light guide to control distribution of scintillation light over the surface of the MPPC array. The output signals of the nine MPPC are multiplexed by a charge division resistor network to generate four position-encoded analog outputs. Flood image, energy resolution and timing resolution measurements were performed using standard NIM electronics. The linearity of the detector response was investigated using gamma-ray sources of different energies. The 10 � 10 array of 0.8 mm LSO crystals was clearly resolved in the flood image. The average energy resolution and standard deviation were 20.0% full-width at half-maximum (FWHM) and �5.0%, respectively, at 511 keV. The timing resolution of a single MPPC coupled to a LSO crystal was found to be 857 ps FWHM, and the value for the central region of detector module was 1182 ps FWHM when �10% energy window was applied. The nonlinear response of a single MPPC when used to read out a single LSO was observed among the corner crystals of the proposed detector module. However, the central region of the detector module exhibits significantly less nonlinearity (6.5% for 511 keV). These results demonstrate that (1) a charge-sharing resistor network can effectively multiplex MPPC signals and reduce the number of output signals without significantly degrading the performance of a PET detector and (2) a custom light guide to permit light sharing among multiple MPPC and to diffuse and direct scintillation light can reduce the nonlinearity of the detector response within the limited dynamic range of a typical MPPC. As a result, the proposed PET detector module has the potential to be refined for use in high-resolution PET insert applications. PMID:20393236
Song, Tae Yong; Wu, Heyu; Komarov, Sergey; Siegel, Stefan B; Tai, Yuan-Chuan
Characterization and simulation of linear scintillator arrays for low-energy x-ray detection
NASA Astrophysics Data System (ADS)
Current x-ray imaging in many industrial and medical applications uses different scintillator materials coupled to photodiode arrays. Knowledge of the light distribution and photoelectron signal allows for the improvement of the imaging properties of such devices. We have measured and simulated the pixel scintillation light distribution collected by the photodiode arrays for four commercial scintillator arrays made of cesium iodide, cadmium tungstate and gadolinium oxysulfide with pitches of 0.8 mm and 1.6 mm. We used a collimated low-energy x-ray beam to study the collected signal in each array element and the effective fill factors determined from the photodiode geometry, backing material and radiation transport in the scintillator. A proper description of the optical parameters of these detectors provides excellent agreement of the experimental results with Monte Carlo simulations performed with MANTIS.
Franco, L.; G�mez, F.; Badano, A.
Operational performance characteristics of the WISH detector array on the ISIS spallation neutron source
NASA Astrophysics Data System (ADS)
The performance of the position sensitive neutron detector array of the WISH diffractometer is discussed. WISH (Wide angle In a Single Histogram) is one of the seven instruments currently available for users on the second target station (TS2) of the ISIS spallation neutron source, and is used mainly for magnetic studies of materials. WISH is instrumented with an array of 10 detector panels, covering an angular range of 320o, orientated in two semi-cylindrical annuli around a central sample position at a radius of 2.2m. In total the 10 detector panels are composed of 1520 3He based position sensitive detector tubes. Each tube has an active length of one metre, a diameter of 8mm and is filled with 3He at 15 bar. The specification for the WISH detectors included a neutron detection efficiency of 50% at a neutron wavelength of 1� with good gamma rejection. A position resolution better than 8 mm FWHM along the length of the tubes was also required which has been met experimentally. Results obtained from the detector arrays showing pulse height and positional information both prior to and post installation are shown. The first 5 of the 10 detector panels have been operational since 2009, and comparable diffraction data from powder and single crystal samples taken from the remaining 5 panels (installation completed in 2013) shows that we have a detector array with a highly stable performance which is easily assembled and maintained. Finally some real user data is shown, highlighting the excellent quality of data attainable with this instrument.
Duxbury, D.; Khalyavin, D.; Manuel, P.; Raspino, D.; Rhodes, N.; Schooneveld, E.; Spill, E.
Charge sharing and charge loss in a cadmium�zinc�telluride fine-pixel detector array
Because of its high atomic number, room temperature operation, low noise, and high spatial resolution a cadmium�zinc�telluride multi-pixel detector is ideal for hard X-ray astrophysical observation. As part of on-going research at MSFC to develop multi-pixel CdZnTe detectors for this purpose, we have measured charge sharing and charge loss for a 4�4 (750?m pitch), 1mm thick pixel array and modeled
J. A. Gaskin; D. P. Sharma; B. D. Ramsey
Charge sharing and charge loss in a cadmium-zinc-telluride fine-pixel detector array
Because of its high atomic number, room temperature operation, low noise, and high spatial resolution a cadmium-zinc-telluride multi-pixel detector is ideal for hard X-ray astrophysical observation. As part of on-going research at MSFC to develop multi-pixel CdZnTe detectors for this purpose, we have measured charge sharing and charge loss for a 4�4 (750mum pitch), 1mm thick pixel array and modeled
J. A. Gaskin; D. P. Sharma; B. D. Ramsey
Circuit for high resolution decoding of multi-anode microchannel array detectors
NASA Technical Reports Server (NTRS)
A circuit for high resolution decoding of multi-anode microchannel array detectors consisting of input registers accepting transient inputs from the anode array; anode encoding logic circuits connected to the input registers; midpoint pipeline registers connected to the anode encoding logic circuits; and pixel decoding logic circuits connected to the midpoint pipeline registers is described. A high resolution algorithm circuit operates in parallel with the pixel decoding logic circuit and computes a high resolution least significant bit to enhance the multianode microchannel array detector's spatial resolution by halving the pixel size and doubling the number of pixels in each axis of the anode array. A multiplexer is connected to the pixel decoding logic circuit and allows a user selectable pixel address output according to the actual multi-anode microchannel array detector anode array size. An output register concatenates the high resolution least significant bit onto the standard ten bit pixel address location to provide an eleven bit pixel address, and also stores the full eleven bit pixel address. A timing and control state machine is connected to the input registers, the anode encoding logic circuits, and the output register for managing the overall operation of the circuit.
Kasle, David B. (inventor)
assignments. These FPAs have subsequently been integrated into the NICMOS flight dewar and are now being characterization and calibration of the detectors in the fully integrated NICMOS system will be carried out during the System Level Thermal Vacuum (SLTV) test, scheduled for late spring/early summer of 1996. The values
Schneider, Glenn
Status of LWIR HgCdTe infrared detector technology
NASA Technical Reports Server (NTRS)
The performance requirements that today's advanced Long Wavelength Infrared (LWIR) focal plane arrays place on the HgCdTe photovoltaic detector array are summarized. The theoretical performance limits for intrinsic LWIR HgCdTe detectors are reviewed as functions of cutoff wavelength and operating temperature. The status of LWIR HgCdTe photovoltaic detectors is reviewed and compared to the focal plane array (FPA) requirements and to the theoretical limits. Emphasis is placed on recent data for two-layer HgCdTe PLE heterojunction photodiodes grown at Loral with cutoff wavelengths ranging between 10 and 19 microns at temperatures of 70 to 80 K. Development trends in LWIR HgCdTe detector technology are outlined, and conclusions are drawn about the ability for photovoltaic HgCdTe detector arrays to satisfy a wide variety of advanced FPA array applications.
Reine, M. B.
Vertical Isolation for Photodiodes in CMOS Imagers
NASA Technical Reports Server (NTRS)
In a proposed improvement in complementary metal oxide/semi conduct - or (CMOS) image detectors, two additional implants in each pixel would effect vertical isolation between the metal oxide/semiconductor field-effect transistors (MOSFETs) and the photodiode of the pixel. This improvement is expected to enable separate optimization of the designs of the photodiode and the MOSFETs so as to optimize their performances independently of each other. The purpose to be served by enabling this separate optimization is to eliminate or vastly reduce diffusion cross-talk, thereby increasing sensitivity, effective spatial resolution, and color fidelity while reducing noise.
Pain, Bedabrata
Photodiode-Based X-Ray Beam-Position Monitor With High Spatial-Resolution for the NSLS-II Beamlines
We developed a photodiode-based monochromatic X-ray beam-position monitor (X-BPM) with high spatial resolution for the project beamlines of the NSLS-II. A ring array of 32 Si PIN-junction photodiodes were designed for use as a position sensor, and a low-noise HERMES4 ASIC chip was integrated into the electronic readout system. A series of precision measurements to characterize electrically the Si-photodiode sensor and the ASIC chip demonstrated that the inherent noise is sufficiently below tolerance levels. Following up modeling of detector's performance, including geometrical optimization using a Gaussian beam, we fabricated and assembled a first prototype. In this paper, we describe the development of this new state-of-the-art X-ray BPM along the beamline, in particular, downstream from the monochromator.
Yoon, P.S.; Siddons, D. P.
Progress with type-II superlattice IR detector arrays
We report progress in the development of long wavelength infrared (LWIR) focal plane arrays (FPAs) built on type-II strained layer InAs\\/GaSb superlattice materials. Work at Raytheon Vision Systems and Jet Propulsion Laboratory has led to successful devices with cutoff wavelengths in the 10 to 12 mum range. Pixels have been formed by wet etching and surface passivation by plasma-deposited silicon
David R. Rhiger; Robert E. Kvaas; Sean F. Harris; Richard E. Bornfreund; Yen N. Thai; Cory J. Hill; Jian V. Li; Sarath D. Gunapala; Jason M. Mumolo
Dual source and dual detector arrays tetrahedron beam computed tomography for image guided radiotherapy.
Cone-beam computed tomography (CBCT) is an important online imaging modality for image guided radiotherapy. But suboptimal image quality and the lack of a real-time stereoscopic imaging function limit its implementation in advanced treatment techniques, such as online adaptive and 4D radiotherapy. Tetrahedron beam computed tomography (TBCT) is a novel online imaging modality designed to improve on the image quality provided by CBCT. TBCT geometry is flexible, and multiple detector and source arrays can be used for different applications. In this paper, we describe a novel dual source-dual detector TBCT system that is specially designed for LINAC radiation treatment machines. The imaging system is positioned in-line with the MV beam and is composed of two linear array x-ray sources mounted aside the electrical portal imaging device and two linear arrays of x-ray detectors mounted below the machine head. The detector and x-ray source arrays are orthogonal to each other, and each pair of source and detector arrays forms a tetrahedral volume. Four planer images can be obtained from different view angles at each gantry position at a frame rate as high as 20 frames per second. The overlapped regions provide a stereoscopic field of view of approximately 10-15�cm. With a half gantry rotation, a volumetric CT image can be reconstructed having a 45�cm field of view. Due to the scatter rejecting design of the TBCT geometry, the system can potentially produce high quality 2D and 3D images with less radiation exposure. The design of the dual source-dual detector system is described, and preliminary results of studies performed on numerical phantoms and simulated patient data are presented. PMID:24434681
Kim, Joshua; Lu, Weiguo; Zhang, Tiezhi
Dual source and dual detector arrays tetrahedron beam computed tomography for image guided radiotherapy
NASA Astrophysics Data System (ADS)
Cone-beam computed tomography (CBCT) is an important online imaging modality for image guided radiotherapy. But suboptimal image quality and the lack of a real-time stereoscopic imaging function limit its implementation in advanced treatment techniques, such as online adaptive and 4D radiotherapy. Tetrahedron beam computed tomography (TBCT) is a novel online imaging modality designed to improve on the image quality provided by CBCT. TBCT geometry is flexible, and multiple detector and source arrays can be used for different applications. In this paper, we describe a novel dual source-dual detector TBCT system that is specially designed for LINAC radiation treatment machines. The imaging system is positioned in-line with the MV beam and is composed of two linear array x-ray sources mounted aside the electrical portal imaging device and two linear arrays of x-ray detectors mounted below the machine head. The detector and x-ray source arrays are orthogonal to each other, and each pair of source and detector arrays forms a tetrahedral volume. Four planer images can be obtained from different view angles at each gantry position at a frame rate as high as 20 frames per second. The overlapped regions provide a stereoscopic field of view of approximately 10-15 cm. With a half gantry rotation, a volumetric CT image can be reconstructed having a 45 cm field of view. Due to the scatter rejecting design of the TBCT geometry, the system can potentially produce high quality 2D and 3D images with less radiation exposure. The design of the dual source-dual detector system is described, and preliminary results of studies performed on numerical phantoms and simulated patient data are presented.
Kim, Joshua; Lu, Weiguo; Zhang, Tiezhi
High performance SPAD array detectors for parallel photon timing applications
NASA Astrophysics Data System (ADS)
Over the past few years there has been a growing interest in monolithic arrays of single photon avalanche diodes (SPAD) for spatially resolved detection of faint ultrafast optical signals. SPADs implemented in planar technologies offer the typical advantages of microelectronic devices (small size, ruggedness, low voltage, low power, etc.). Furthermore, they have inherently higher photon detection efficiency than PMTs and are able to provide, beside sensitivities down to single-photons, very high acquisition speeds. Although currently available silicon devices reached remarkable performance, nevertheless further improvements are needed in order to meet the requirements of most demanding timeresolved techniques, it is necessary to face problems like electrical crosstalk between adjacent pixel, high detection efficiency in the red spectral range, large area, low dark counting rate. Moreover to develop array with high number of pixel became more and more important to develop all the TCSPC electronics with picosecond resolution to create a new family of detection system for TCSPC applications. Recent advances in our research on single photon time resolved array is here presented.
Rech, I.; Cammi, C.; Crotti, M.; Gulinatti, A.; Maccagnani, P.; Ghioni, M.; Cova, S.
Detector Arrays for the James Webb Space Telescope Near-Infrared Spectrograph
NASA Technical Reports Server (NTRS)
The James Webb Space Telescope's (JWST) Near Infrared Spectrograph (NIRSpec) incorporates two 5 micron cutoff (lambda(sub co) = 5 microns) 2048x2048 pixel Teledyne HgCdTe HAWAII-2RG sensor chip assemblies. These detector arrays, and the two Teledyne SIDECAR application specific integrated circuits that control them, are operated in space at T approx. 37 K. In this article, we provide a brief introduction to NIRSpec, its detector subsystem (DS), detector readout in the space radiation environment, and present a snapshot of the developmental status of the NIRSpec DS as integration and testing of the engineering test unit begins.
Rauscher, Bernard J.; Alexander, David; Brambora, Clifford K.; Derro, Rebecca; Engler, Chuck; Fox, Ori; Garrison, Matthew B.; Henegar, Greg; Hill, robert J.; Johnson, Thomas; Lindler, Don J.; Manthripragada, Sridhar S.; Marshall, Ceryl; Mott, Brent; Parr, Thomas M.; Roher, Wayne D.; Shakoorzadeh, Kamdin B.; Smith, Miles; Waczynski, Augustyn; Wen, Yiting; Wilson, Donna; Xia-Serafino, Wei
Laboratory characterization of direct readout Si:Sb and Si:Ga infrared detector arrays
NASA Technical Reports Server (NTRS)
Highlights of recent results obtained at Ames Research Center in performance evaluations of infrared detector arrays are presented. Antimony- and gallium-doped silicon direct readout 58x62 element hybrid devices from Ames' ongoing detector technology development program are described. The observed characteristics meet most of the performance goals specified by the Space Infrared Telescope Facility (SIRTF) instrument teams and compare favorably with the best performance reported for discrete non-integrating extrinsic silicon detectors. Initial results of radiation environment testing are reported, and non-ideal behavior demonstrated by these test devices is discussed.
Mckelvey, Mark E.; Moss, Nicolas N.; Mcmurray, R. E., Jr.; Estrada, John A.; Goebel, John H.; Mccreight, Craig R.; Savage, Maureen L.; Junga, Frank; Whittemore, Thomas
Silicon Wafer-Scale Substrate for Microshutters and Detector Arrays
NASA Technical Reports Server (NTRS)
The silicon substrate carrier was created so that a large-area array (in this case 62,000+ elements of a microshutter array) and a variety of discrete passive and active devices could be mounted on a single board, similar to a printed circuit board. However, the density and number of interconnects far exceeds the capabilities of printed circuit board technology. To overcome this hurdle, a method was developed to fabricate this carrier out of silicon and implement silicon integrated circuit (IC) technology. This method achieves a large number of high-density metal interconnects; a 100-percent yield over a 6-in. (approximately equal to 15-cm) diameter wafer (one unit per wafer); a rigid, thermally compatible structure (all components and operating conditions) to cryogenic temperatures; re-workability and component replaceability, if required; and the ability to precisely cut large-area holes through the substrate. A method that would employ indium bump technology along with wafer-scale integration onto a silicon carrier was also developed. By establishing a silicon-based version of a printed circuit board, the objectives could be met with one solution. The silicon substrate would be 2 mm thick to survive the environmental loads of a launch. More than 2,300 metal traces and over 1,500 individual wire bonds are required. To mate the microshutter array to the silicon substrate, more than 10,000 indium bumps are required. A window was cut in the substrate to allow the light signal to pass through the substrate and reach the microshutter array. The substrate was also the receptacle for multiple unpackaged IC die wire-bonded directly to the substrate (thus conserving space over conventionally packaged die). Unique features of this technology include the implementation of a 2-mmthick silicon wafer to withstand extreme mechanical loads (from a rocket launch); integrated polysilicon resistor heaters directly on the substrate; the precise formation of an open aperture (approximately equal to 3x3cm) without any crack propagation; implementation of IR transmission blocking techniques; and compatibility with indium bump bonding. Although designed for the microshutter arrays for the NIRSpec instrument on the James Webb Space Telescope, these substrates can be linked to microshutter applications in the photomask generation and stepper equipment used to make ICs and microelectromechanical system (MEMS) devices.
Jhabvala, Murzy; Franz, David E.; Ewin, Audrey J.; Jhabvala, Christine; Babu, Sachi; Snodgrass, Stephen; Costen, Nicholas; Zincke, Christian
Photon detection with cooled avalanche photodiodes
NASA Technical Reports Server (NTRS)
Commercial avalanche photodiodes have been operated as single-photon detectors at an optimum operating temperature and bias voltage. These detectors were found to be 1.5-3 times more sensitive than presently available photomultiplier tubes (PMTs). Both single-photon detection probability and detector noise increase with bias voltage; detection probabilities greater than twice that of a PMT were obtained with detector noise levels below 100 counts per second. Higher probabilities were measured at higher noise levels. The sources of noise and their dependence on temperature and bias voltage are discussed.
Robinson, D. L.; Metscher, B. D.
Cooled avalanche photodiode used for photon detection
NASA Technical Reports Server (NTRS)
Commercial avalanche photodiodes have been operated as single-photon detectors at an optimum operating temperature and bias voltage. These detectors were found to be 1.5 to 3 times more sensitive than presently-available photomultiplier tubes (PPMTs). Both single-photon detection probability and detector noise increase with bias voltage; detection probabilities greater than 25 percent were obtained with detector noise levels comparable to the noise of a PMT; higher probabilities were measured at higher noise levels. The sources of noise and their dependence on temperature and bias voltage are discussed.
Robinson, Deborah L.; Metscher, Brian D.
Digital Radiography and Computed Tomography Project -- Fully Integrated Linear Detector ArrayStatus Report
The field-portable Digital Radiography and Computed Tomography (DRCT) x-ray inspection systems developed for the Project Manager for NonStockpile Chemical Materiel (PMNSCM) over the past 13 years have used linear diode detector arrays from two manufacturers; Thomson and Thales. These two manufacturers no longer produce this type of detector. In the interest of insuring the long term viability of the portable DRCT single munitions inspection systems and to improve the imaging capabilities, this project has been investigating improved, commercially available detectors. During FY-10, detectors were evaluated and one in particular, manufactured by Detection Technologies (DT), Inc, was acquired for possible integration into the DRCT systems. The remainder of this report describes the work performed in FY-11 to complete evaluations and fully integrate the detector onto a representative DRCT platform.
Tim Roney; Robert Seifert; Bob Pink; Mike Smith
Development of 256 x 256 Element Impurity Band Conduction Infrared Detector Arrays for Astronomy
NASA Technical Reports Server (NTRS)
This report describes the work performed on a one and a half year advance technology program to develop Impurity Band Conduction (IBC) detectors with very low dark current, high quantum efficiency, and with good repeatable processes. The program fabricated several epitaxial growths of Si:As detecting layers from 15 to 35 microns thick and analyzed the performance versus the thickness and the Arsenic concentration of these epitaxial layers. Some of the epitaxial runs did not yield because of excessive residual impurities. The thicker epitaxial layers and the ones with higher Arsenic concentration resulted in good detectors with low dark currents and good quantum efficiency. The program hybridized six detector die from the best detector wafers to a low noise, 256 x 256 readout array and delivered the hybrids to NASA Ames for a more detailed study of the performance of the detectors.
Domingo, George
Highly segmented detector arrays for studying the resonant decay of unstable nuclei
NASA Astrophysics Data System (ADS)
Resonant spectroscopy of short-lived nuclei produced in nucleus-nucleus collisions can provide information on the nature of the nuclear surface and the formation of clusters. Detection of these resonant decays requires detector arrays with good energy and angular resolution. This newest generation of detector array is typically comprised of silicon strip detectors with several hundred to several thousand independent segments. As a key issue of such arrays is the processing of their signals, we report on the development of a non-ASIC system designed to simplify the analog processing and readout from a highly segmented silicon detector array. The non-ASIC system called MASE (multiplexed analog shaper electronics) focuses on providing good energy resolution and adequate timing information for up to 4096 channels. It consists of 16-channel boards which can be either used independently or as part of a larger system. The analog portion of each channel has low and high gain shapers with associated leading edge discriminators and peak hold circuits. The logic for readout of the analog signals is performed by two FPGA chips located on each board. Readout of MASE channels is multiplexed. Logical signals are transferred via LVDS while the analog signals are sequenced into a multisampling ADC. Signals are also multiplexed for inspection purposes. Shaper gains and discriminator thresholds are adjustable through DACs via a USB interface.
deSouza, Romualdo T.; Metelko, Carl; Hudan, Sylvie
Analyzing the performance of a nanosatellite cluster-detector array receiver for laser communication
This work analyzes laser communication between a cluster of nanosatellites, which is a concentrated formation of small lightweight satellites and a ground station. The scenario under consideration is a cluster of nanosatellites communicating by means of a laser beam with a detector array receiver that is located on the earth's surface and equipped with a common optical system for all
Denis Bushuev; Debbie Kedar; Shlomi Arnon
Converting films for x-ray detectors, applied to amorphous silicon arrays.
This paper presents results from our on-going efforts to characterize semiconductor thin films for direct x-ray conversion. We deposit these thin films onto an amorphous silicon (a-Si:H) readout array with the overall goal of developing a large area x-ray detector for protein crystallography, and for other x-ray imaging fields.
Ross, S.; Zentai, G.
The GERMANIUM DETECTOR ARRAY ( GERDA) for the search of neutrinoless ?? decays of 76Ge at LNGS
NASA Astrophysics Data System (ADS)
This paper describes the proposed GERDA experiment, the GERMANIUM DETECTOR ARRAY for the search of neutrinoless ?? decays of 76Ge at LNGS. The goal of the GERDA project is to operate bare germanium diodes enriched in 76Ge in an (optional active) cryogenic fluid shield with a sensitivity for neutrinoless ?? decay of T>2?10 years after an exposure of 100 kg ? years.
Sch�nert, S.; Abt, I.; Altmann, M.; Bakalyarov, A. M.; Barabanov, I.; Bauer, C.; Bauer, M.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Bettini, A.; Bezrukov, L.; Brudanin, V.; B�ttner, C.; Bolotsky, V. P.; Caldwell, A.; Cattadori, C.; Chirchenko, M. V.; Chkvorets, O.; Clement, H.; Demidova, E.; di Vacri, A.; Eberth, J.; Egorov, V.; Farnea, E.; Gangapshev, A.; Grigoriev, G. Y.; Gurentsov, V.; Gusev, K.; Hampel, W.; Heusser, G.; Hofmann, W.; Inzhechik, L. V.; Jochum, J.; Junker, M.; Katulina, S.; Kiko, J.; Kirpichnikov, I. V.; Klimenko, A.; Kn�pfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kotthaus, R.; Kusminov, V.; Laubenstein, M.; Lebedev, V. I.; Liu, X.; Moser, H.-G.; Nemchenok, I.; Pandola, L.; Peiffer, P.; Richter, R. H.; Rottler, K.; Rossi Alvarez, C.; Sandukovsky, V.; Sch�nert, S.; Scholl, S.; Schreiner, J.; Schwingenheuer, B.; Simgen, H.; Smolnikov, A.; Tikhomirov, A. V.; Tomei, C.; Ur, C. A.; Vasenko, A. A.; Vasiliev, S.; Wei�haar, D.; Wojcik, M.; Yanovich, E.; Yurkowski, J.; Zhukov, S. V.; Zuzel, G.; Gerda Collaboration
Electronics for the Extensive Air Shower Detector Array at the University of Puebla
In this paper we describe in detail the electronics cards that were designed to be the basis of the data acquisition system (DAS) of the extensive air shower detector array built in the Campus of the University of Puebla. The purpose of this observatory is to measure the energy and arrival direction of primary cosmic rays with energies around 1015
E. P�rez; R. Conde; O. Mart�nez; T. Murrieta; H. Salazar; L. Villase�or
Multiplexed Readout of MMC Detector Arrays Using Non-hysteretic rf-SQUIDs
NASA Astrophysics Data System (ADS)
Metallic magnetic calorimeters (MMCs) are widely used for various experiments in fields ranging from atomic and nuclear physics to X-ray spectroscopy, laboratory astrophysics or material science. Whereas in previous experiments single pixel detectors or small arrays have been used, for future applications large arrays are needed. Therefore, suitable multiplexing techniques for MMC arrays are currently under development. A promising approach for the readout of large arrays is the microwave SQUID multiplexer that employs non-hysteretic rf-SQUIDs to create a frequency shift of high resonators that is in accordance with the detector signal and that can be monitored by using standard microwave measurement techniques. In this paper we discuss the design of a recently developed and fabricated 64 pixel detector array with integrated microwave SQUID multiplexer that was produced to test the suitability of this readout technique. The characterization of dc-SQUIDs with virtually identical washer design compared to the rf-SQUIDs of the SQUID multiplexer revealed that the crucial SQUID parameters such as the critical current of the Josephson junctions or the washer inductance are close to the design values and anticipates a successful operation of the SQUID multiplexer.
Kempf, S.; Wegner, M.; Gastaldo, L.; Fleischmann, A.; Enss, C.
Development of Yangbajing Air shower Core detector array for a new EAS hybrid Experiment
Aiming at the observation of cosmic-ray chemical composition at the "knee" energy region, we have been developinga new type air-shower core detector (YAC, Yangbajing Air shower Core detector array) to be set up at Yangbajing (90.522$^\\circ$ E, 30.102$^\\circ$ N, 4300 m above sea level, atmospheric depth: 606 g/m$^2$) in Tibet, China. YAC works together with the Tibet air-shower array (Tibet-III) and an underground water cherenkov muon detector array (MD) as a hybrid experiment. Each YAC detector unit consists of lead plates of 3.5 cm thick and a scintillation counter which detects the burst size induced by high energy particles in the air-shower cores. The burst size can be measured from 1 MIP (Minimum Ionization Particle) to $10^{6}$ MIPs. The first phase of this experiment, named "YAC-I", consists of 16 YAC detectors each having the size 40 cm $\\times$ 50 cm and distributing in a grid with an effective area of 10 m$^{2}$. YAC-I is used to check hadronic interaction models. The second phase of the experiment,...
Liu, Jinsheng; Chen, Ding; Zhang, Ying; Zhai, Liuming; Chen, Xu; Hu, Xiaobin; Lin, Yuhui; Zhang, Xueyao; Feng, Cunfeng; Jia, Huanyu; Zhou, Xunxiu; DanZengLuoBu,; Chen, Tianlu; Li, Haijin; Liu, Maoyuan; Yuan, Aifang
High resolution positron emission tomography with a prototype camera based on solid state scintillation detectors
The prototype of a high-resolution PET (positron emission tomography) camera consisting of two opposite arrays of detectors with independent solid-state readout was built and tested. The basic detector unit is the RCA C30994 detector module consisting of two 3-mm�5-mm�20-mm BGO scintillators, each coupled to one silicon avalanche photodiode. The two-dimensional stacking capability of the module allows a high-resolution multiring detection
R. Lecomte; J. Cadorette; A. Jouan; M. Heon; D. Rouleau; G. Gauthier
Characterization of One-Dimensional Fiber-Optic Scintillating Detectors for Electron-Beam Therapy Dosimetry
In this study, a one-dimensional fiber-optic scintillating detector was developed for electron-beam therapy dosimetry. Each fiber-optic detector contains an organic scintillator as a sensitive volume and it is embedded and arrayed in a plastic phantom to measure one-dimensional high-energy electron-beam profiles of clinical linear accelerators. Plastic optical fibers guide the scintillating light which each detector probe generates to a photodiode
Bongsoo Lee; Kyoung Won Jang; Dong Hyun Cho; Wook Jae Yoo; Sang Hun Shin; Gye-Rae Tack; Soon-Cheol Chung; Sin Kim; Hyosung Cho; Byung Gi Park; Joo Hyun Moon; Siyong Kim
Design and testing of a high-speed low-noise infrared detector array
NASA Astrophysics Data System (ADS)
For infrared laser remote sensing, a direct detection receiver may be optimally designed around a high speed, low noise focal plane array (FPA). Short pulse, high repetition rate operation of the laser transmitter makes it beneficial to operate the detector with short integration times, lowering the limiting integrated background photon flux. With this photon signal (which constitutes a noise contribution) made small enough, improved low-noise readout integrated circuits (ROIC) can be used to realize a significantly improved imaging lidar receiver. A 10 by 10 pixel ROIC has recently been designed and fabricated. Demonstrated capabilities include > 100 kHz frame rate, 50 ns integration time, and less than 100 e- of input-referred readout noise. These ROICs have been mated with long-wavelength HgCdTe infrared detector arrays, with cutoff wavelengths greater than 11 micrometer. Characteristics of the demonstrated ROIC design will be presented, along with testing of the focal plane arrays hybridized to them.
Jacobson, Phillip L.; Busch, George E.; Jolin, L. John; Wang, Peter C.; Cannata, Robert F.; Kincaid, Glenn T.; Gurgenian, Ray K.; Mesropian, Shoghig
Recent progress with multi-anode microchannel array detector systems. [for use in instruments on telescopes
NASA Technical Reports Server (NTRS)
The construction and modes of operation of Multi-Anode Microchannel Arrays (MAMA's) are briefly reviewed. The MAMA detectors, which are a family of photoelectric, photon-counting array detectors being developed specifically for use in instruments on ground-based and space-borne telescopes, combine the high sensitivity and photometric stability of a conventional channel electron multiplier with a high-resolution imaging capability. The MAMA detectors feature low applied potential (less than 3 kV), high gain (greater than 10 to the 6th electrons/pulse), an absolute event timing accuracy of 100 ns or better, a very long count lifetime (greater than 2.5 x 10 to the 11th counts/sq mm), and a power consumption of less than 30 W for a complete system
Timothy, J. G.
Multiple detector focal plane array ultraviolet spectrometer for the AMPS laboratory
NASA Technical Reports Server (NTRS)
The possibility of meeting the requirements of the amps spectroscopic instrumentation by using a multi-element focal plane detector array in a conventional spectrograph mount was examined. The requirements of the detector array were determined from the optical design of the spectrometer which in turn depends on the desired level of resolution and sensitivity required. The choice of available detectors and their associated electronics and controls was surveyed, bearing in mind that the data collection rate from this system is so great that on-board processing and reduction of data are absolutely essential. Finally, parallel developments in instrumentation for imaging in astronomy were examined, both in the ultraviolet (for the Large Space Telescope as well as other rocket and satellite programs) and in the visible, to determine what progress in that area can have direct bearing on atmospheric spectroscopy.
Feldman, P. D.
CdZnTe and CdTe detector arrays for hard X-ray and gamma-ray astronomy
A variety of CdZnTe and CdTe detector arrays were fabricated at NASA\\/GSFC for use in hard X-ray and gamma-ray astronomy. Mosaic, pixel, and 3-D position-sensitive detector arrays were built to demonstrate the capabilities for high-resolution imaging and spectroscopy for 10 to 2MeV. This paper will summarize the different arrays and their applications for instruments being developed at NASA\\/GSFC. Specific topics
C. M Stahle; B. H Parker; A. M Parsons; L. M Barbier; S. D Barthelmy; N. A Gehrels; D. M Palmer; S. J Snodgrass; J Tueller
Fabrication of Metallic Magnetic Calorimeter X-ray Detector Arrays
NASA Astrophysics Data System (ADS)
Microcalorimeters with metallic magnetic sensors show great promise for use in astronomical X-ray spectroscopy. We describe the design and fabrication of a lithographically patterned magnetic microcalorimeter. A paramagnetic AuEr film is sputter-deposited as the sensor, which is coupled to a low noise SQUID via a meander superconducting pickup loop used as an inductor. This inductor also provides the magnetic field bias to the sensor. The AuEr film is deposited over this meander such that the field created by a large current flowing in the loop magnetizes the sensor material. The use of thin film techniques in the fabrication of these magnetic sensors not only allows strong magnetic coupling between the sensor and the inductor, it also is scalable for array fabrication.
Hsieh, W.-T.; Adams, J. A.; Bandler, S. R.; Beyer, J.; Denis, K. L.; Eguchi, H.; Figueroa-Feliciano, E.; Rotzinger, H.; Schneider, G. H.; Seidel, G. M.; Stevenson, T. R.; Travers, D. E.
NORSAR Final Scientific Report Adaptive Waveform Correlation Detectors for Arrays: Algorithms for Autonomous Calibration
Correlation detection is a relatively new approach in seismology that offers significant advantages in increased sensitivity and event screening over standard energy detection algorithms. The basic concept is that a representative event waveform is used as a template (i.e. matched filter) that is correlated against a continuous, possibly multichannel, data stream to detect new occurrences of that same signal. These algorithms are therefore effective at detecting repeating events, such as explosions and aftershocks at a specific location. This final report summarizes the results of a three-year cooperative project undertaken by NORSAR and Lawrence Livermore National Laboratory. The overall objective has been to develop and test a new advanced, automatic approach to seismic detection using waveform correlation. The principal goal is to develop an adaptive processing algorithm. By this we mean that the detector is initiated using a basic set of reference ('master') events to be used in the correlation process, and then an automatic algorithm is applied successively to provide improved performance by extending the set of master events selectively and strategically. These additional master events are generated by an independent, conventional detection system. A periodic analyst review will then be applied to verify the performance and, if necessary, adjust and consolidate the master event set. A primary focus of this project has been the application of waveform correlation techniques to seismic arrays. The basic procedure is to perform correlation on the individual channels, and then stack the correlation traces using zero-delay beam forming. Array methods such as frequency-wavenumber analysis can be applied to this set of correlation traces to help guarantee the validity of detections and lower the detection threshold. In principle, the deployment of correlation detectors against seismically active regions could involve very large numbers of very specific detectors. To meet this challenge, we have examined two strategies: (1) use of subspace detectors, a multi-dimensional extension of correlators, which allow representation and detection of signals exhibiting some degree of variation; and (2) autonomous calibration of many subspace and correlation detectors in an adaptive detection framework, subject to analyst review. Because correlation detectors are relatively new to seismology, a significant amount of research on how to tune these detectors has been needed to address later calibration efforts that will arise as they are adopted for operational use. We have approached these challenges by carrying out a number of case studies, encompassing various monitoring scenarios such as earthquake aftershock sequences and swarms, recurring mining explosions, other types of explosions, and rockbursts. We have studied several different geographical regions (the European Arctic, Central Asia, and the western United States). We have drawn on available Ground Truth data in assessing the results of the various processing schemes. In all cases, we have benefited from the high-quality seismic arrays or networks available in these regions, and we have thus been able to evaluate the performance of array-based correlation processing under a variety of conditions. The main results of the project are summarized as follows: (1) Array-based waveform correlation has been demonstrated to lower significantly detection thresholds in comparison with standard single-channel waveform correlation. (2) Frequency-wavenumber analysis of the correlation traces on a small-aperture array provides an effective method for screening out a certain category of false alarms, and can therefore be used to improve detector sensitivity by lowering the threshold for automatic array detection. (3) We have developed and tested a framework for autonomous correlation detection. The framework comprises a set of conventional (STA/LTA) detectors on a collection of array beams, augmented by correlation and subspace detectors. The detectors are applied in parallel. (4) We have expe
Gibbons, S J; Ringdal, F; Harris, D B
Dynamic range considerations for EUV MAMA detectors. [Extreme UV Multianode Microchannel Array
NASA Technical Reports Server (NTRS)
The multianode microchannel array (MAMA) has been chosen as the detector for two instruments on the ESA/NASA Solar Heliospheric Observatory. The response of the MAMA to the two extreme types of solar spectra, disk and corona, have been modeled with a view toward evaluating dynamic range effects present. The method of MAMA operation is discussed, with emphasis given to modeling the effect of electron cloud charge spreading to several detector anodes and amplifiers (n-fold events). Representative synthetic EUV spectra have been created. The detector response to these spectra is modeled by dissecting the input photon radiation field across the detector array into contributions to the various amplifier channels. The results of this dissection are shown for spectral regions across the entire wavelength region of interest. These results are used to identify regions in which total array photon counting rate or individual amplifier rate may exceed the design limits. This allows the design or operational modes to be tailored to eliminate the problem areas.
Illing, Rainer M. E.; Bybee, Richard L.; Timothy, J. G.
MEGHNAD - A multi element detector array for heavy ion collision studies
NASA Astrophysics Data System (ADS)
In the coming decade, the expanding field of experimental nuclear physics in our country is going to see a quantum leap in research and developmental activities with new accelerator facilities like the variable energy cyclotron with ECR heavy ion source, the upcoming K-500 superconducting cyclotron, both at VECC, Calcutta, and the superconducting linac boosters at both the Pelletron Accelerator Facilities at TIFR, Mumbai and NSC, New Delhi. When heavy ion beam available from such machines fall on a target and undergo collision, very rich and often pristine fields of research open up. In order to carry on such activities, we have taken up a project to build a multi element gamma, heavy ion and neutron array of detectors (MEGHNAD) to detect and study the properties of a wide variety of particles like neutrons, protons, light mass clusters, massive ejected fragments, and gamma rays with good solid angle coverage and efficiency. Design of the detector array, performance of the prototype detector and brief outline of the research programme to be undertaken with the detector array will be discussed.
Saha, Satyajit
Improving the angular resolution for the silicon detectors of the STARS array
NASA Astrophysics Data System (ADS)
The STARS (Silicon Telescope Array for Reaction Studies) array at LBNL is used to measure the emission angles of light charged particles (protons, deuterons and tritons) following transfer reactions. The array consists of two CD-shaped silicon energy detectors: a thin ``delta E'' detector and a thicker ``E'' detector, each segmented into twenty-four concentric rings. The angle at which a particle hits the delta E detector is typically approximated in the off-line analysis code as the angle from the beam axis to the center of the ring traversed by the particle. To improve angular resolution, a new method of approximating the angle was investigated. It was thought that energy loss in the delta E could be used to derive angle. SRIM was used to create functions of energy loss per unit distance with respect to particle energy. These functions were used in Fortran codes to create matrices of energy loss for a range of angles and final energies. The matrices were then worked into the off-line analysis code. Preliminary results will be shown. This work is partly supported by the DOE under grant numbers DE-FG02-52NA26206 and DE-FG02-05ER41379.
Shaw, John; Pauerstein, Benjamin; Chen, Danyi; Ross, Timothy; Hughes, Richard; Beausang, Con
3D Dose Verification Using Tomotherapy CT Detector Array
Purpose: To evaluate a three-dimensional dose verification method based on the exit dose using the onboard detector of tomotherapy. Methods and Materials: The study included 347 treatment fractions from 24 patients, including 10 prostate, 5 head and neck (HN), and 9 spinal stereotactic body radiation therapy (SBRT) cases. Detector sonograms were retrieved and back-projected to calculate entrance fluence, which was then forward-projected on the CT images to calculate the verification dose, which was compared with ion chamber and film measurement in the QA plans and with the planning dose in patient plans. Results: Root mean square (RMS) errors of 2.0%, 2.2%, and 2.0% were observed comparing the dose verification (DV) and the ion chamber measured point dose in the phantom plans for HN, prostate, and spinal SBRT patients, respectively. When cumulative dose in the entire treatment is considered, for HN patients, the error of the mean dose to the planning target volume (PTV) varied from 1.47% to 5.62% with a RMS error of 3.55%. For prostate patients, the error of the mean dose to the prostate target volume varied from -5.11% to 3.29%, with a RMS error of 2.49%. The RMS error of maximum doses to the bladder and the rectum were 2.34% (-4.17% to 2.61%) and 2.64% (-4.54% to 3.94%), respectively. For the nine spinal SBRT patients, the RMS error of the minimum dose to the PTV was 2.43% (-5.39% to 2.48%). The RMS error of maximum dose to the spinal cord was 1.05% (-2.86% to 0.89%). Conclusions: An excellent agreement was observed between the measurement and the verification dose. In the patient treatments, the agreement in doses to the majority of PTVs and organs at risk is within 5% for the cumulative treatment course doses. The dosimetric error strongly depends on the error in multileaf collimator leaf opening time with a sensitivity correlating to the gantry rotation period.
Sheng Ke, E-mail: firstname.lastname@example.com [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States); Jones, Ryan; Yang Wensha; Saraiya, Siddharth; Schneider, Bernard [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States); Chen Quan; Sobering, Geoff; Olivera, Gustavo [TomoTherapy, Inc., Madison, WI (United States); Read, Paul [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States)
Materials preparation and fabrication of pyroelectric polymer/silicon MOSFET detector arrays. Final report
The authors have delivered several 64-element linear arrays of pyroelectric elements fully integrated on silicon wafers with MOS readout devices. They have delivered detailed drawings of the linear arrays to LANL. They have processed a series of two inch wafers per submitted design. Each two inch wafer contains two 64 element arrays. After spin-coating copolymer onto the arrays, vacuum depositing the top electrodes, and polarizing the copolymer films so as to make them pyroelectrically active, each wafer was split in half. The authors developed a thicker oxide coating separating the extended gate electrode (beneath the polymer detector) from the silicon. This should reduce its parasitic capacitance and hence improve the S/N. They provided LANL three processed 64 element sensor arrays. Each array was affixed to a connector panel and selected solder pads of the common ground, the common source voltage supply connections, the 64 individual drain connections, and the 64 drain connections (for direct pyroelectric sensing response rather than the MOSFET action) were wire bonded to the connector panel solder pads. This entails (64 + 64 + 1 + 1) = 130 possible bond connections per 64 element array. This report now details the processing steps and the progress of the individual wafers as they were carried through from beginning to end.
Bloomfield, P. [Drexel Univ., Philadelphia, PA (United States). Dept. of Materials Engineering
Inverse-geometry volumetric CT system with multiple detector arrays for wide field-of-view imaging
Current volumetric computed tomography (CT) methods require seconds to acquire a thick volume (>8 cm) with high resolution. Inverse-geometry CT (IGCT) is a new system geometry under investigation that is anticipated to be able to image a thick volume in a single gantry rotation with isotropic resolution and no cone-beam artifacts. IGCT employs a large array of source spots opposite a smaller detector array. The in-plane field of view (FOV) is primarily determined by the size of the source array, in much the same way that the FOV is determined by the size of the detector array in a conventional CT system. Thus, the size of the source array can be a limitation on the achievable FOV. We propose adding additional detector arrays, spaced apart laterally, to increase the in-plane FOV while still using a modestly sized source array. We determine optimal detector placement to maximize the FOV while obtaining relatively uniform sampling. We also demonstrate low wasted radiation of the proposed system through design and simulation of a pre-patient collimator. Reconstructions from simulated projection data show no artifacts when combining the data from the detector arrays. Finally, to demonstrate feasibility of the concept, an anthropomorphic thorax phantom containing a porcine heart was scanned on a prototype table-top system. The reconstructed axial images demonstrate a 45 cm in-plane FOV using a 23 cm source array.
Mazin, Samuel R.; Star-Lack, Josh; Bennett, N. Robert; Pelc, Norbert J. [Departments of Electrical Engineering and Radiology, Stanford University, Stanford, California 94305 (United States); NexRay, Inc., Los Gatos, California 95030 (United States); Department of Radiology, Stanford University, Stanford, California 94305 (United States); Departments of Radiology, Bioengineering and Electrical Engineering, Stanford University, Stanford, California 94305 (United States)
Detection and localization of particle-emitting sources with compound-eye inspired detector arrays
NASA Astrophysics Data System (ADS)
We develop methods to detect and localize particle-emitting sources using detector arrays that are inspired by biological compound eyes. The sources of interest may be optical, nuclear, or cosmic; they emit particles such as visible photons, neutrons, protons, or charged particles. Our results may have wide applications to artificial vision, which can be important in robotics (robot vision) or medicine (e.g., artificial eyes for the blind); security, where the detection of nuclear materials is needed; or astronomy. This dissertation consists of three parts. First, we detect a far-field particle source using two directional detector arrays: cubic and spherical. We propose a mean-difference test (MDT) detector, analyze its statistical performance, and show that the MDT has a number of advantages over the generalized likelihood- ratio test (GLRT). Second, we localize the source by proposing a novel biologically inspired detector array, whose configuration generalizes the compound eye of insects. This array combines the advantages of compound eyes (e.g., large field-of-view) and human eyes (e.g., high angular resolution). Based on a statistical model of the array measurements, we analyze the array performance by computing the Cram�rao bound (CRB) on the error in estimating the source direction. We also derive lower bounds on the mean-square angular error (MSAE) of the source localization and investigate the MSAE of two source- direction estimators. Numerical examples, including the optimal array design, are presented to further illustrate the array performance. Third, we derive a statistical angular resolution limit (ARL) on resolving two closely spaced point sources in a three-dimensional frame, which is applicable to various measurement models (e.g., radar, sonar, or astronomy). Using the asymptotic analysis of the GLRT, we derive the ARL with constraints on the probabilities of false alarm and detection. Our results give explicit analytical expression for the ARL that is proportional to the square root of the CRB on the angular source separation, or equivalently to the lower bound on the MSAE.
Liu, Zhi
Photo sensor array technology development
NASA Technical Reports Server (NTRS)
The development of an improved capability photo sensor array imager for use in a Viking '75 type facsimile camera is presented. This imager consists of silicon photodiodes and lead sulfide detectors to cover a spectral range from 0.4 to 2.7 microns. An optical design specifying filter configurations and convergence angles is described. Three electronics design approaches: AC-chopped light, DC-dual detector, and DC-single detector, are investigated. Experimental and calculated results are compared whenever possible using breadboard testing and tolerance analysis techniques. Results show that any design used must be forgiving of the relative instability of lead sulfide detectors. A final design using lead sulfide detectors and associated electronics is implemented by fabrication of a hybrid prototype device. Test results of this device show a good agreement with calculated values.
Rossman, M. W.; Young, V. F.; Beall, J. R.
High-resolution spectroscopy with the multi-anode microchannel array detector systems
NASA Technical Reports Server (NTRS)
The results of a series of high-resolution spectroscopic observations undertaken with a linear (1 x 1024)-pixel visible-light Multi-Anode Microchannel Array (MAMA) detector on the Coudespectrograph of the 2.2-meter telescope at the Mauna Kea Observatory and on the vacuum spectrograph of the McMath Solar telescope at the Kitt Peak National Observatory are described. In addition, the two-dimensional MAMA detector systems with (16 x 1024)-pixel, (24 x 1024)-pixel, and (256 x 1024)-pixel formats which are now being readied for use in a series of ground-based, balloon, and sounding-rocket observing programs are briefly described.
Timothy, J. G.; Joseph, C. L.; Wolf, S. C.
Development of Yangbajing Air shower Core detector array for a new EAS hybrid Experiment
Aiming at the observation of cosmic-ray chemical composition at the "knee" energy region, we have been developinga new type air-shower core detector (YAC, Yangbajing Air shower Core detector array) to be set up at Yangbajing (90.522$^\\circ$ E, 30.102$^\\circ$ N, 4300 m above sea level, atmospheric depth: 606 g/m$^2$) in Tibet, China. YAC works together with the Tibet air-shower array (Tibet-III) and an underground water cherenkov muon detector array (MD) as a hybrid experiment. Each YAC detector unit consists of lead plates of 3.5 cm thick and a scintillation counter which detects the burst size induced by high energy particles in the air-shower cores. The burst size can be measured from 1 MIP (Minimum Ionization Particle) to $10^{6}$ MIPs. The first phase of this experiment, named "YAC-I", consists of 16 YAC detectors each having the size 40 cm $\\times$ 50 cm and distributing in a grid with an effective area of 10 m$^{2}$. YAC-I is used to check hadronic interaction models. The second phase of the experiment, called "YAC-II", consists of 124 YAC detectors with coverage about 500 m$^2$. The inner 100 detectors of 80 cm $\\times $ 50 cm each are deployed in a 10 $\\times$ 10 matrix from with a 1.9 m separation and the outer 24 detectors of 100 cm $\\times$ 50 cm each are distributed around them to reject non-core events whose shower cores are far from the YAC-II array. YAC-II is used to study the primary cosmic-ray composition, in particular, to obtain the energy spectra of proton, helium and iron nuclei between 5$\\times$$10^{13}$ eV and $10^{16}$ eV covering the "knee" and also being connected with direct observations at energies around 100 TeV. We present the design and performance of YAC-II in this paper.
Jinsheng Liu; Jing Huang; Ding Chen; Ying Zhang; Liuming Zhai; Xu Chen; Xiaobin Hu; Yuhui Lin; Xueyao Zhang; Cunfeng Feng; Huanyu Jia; Xunxiu Zhou; DanZengLuoBu; Tianlu Chen; Haijin Li; Maoyuan Liu; Aifang Yuan
Design of multi-spot sensor array detector for toxic gas based on spectral analysis
NASA Astrophysics Data System (ADS)
According to the requirement of single-component toxic gases recognition and trace concentration measurement, a novel gas-sensitive sensor array is developed, which chooses metallic porphyrin as sensitive material. Moreover, the multi-spot sensor array detector is designed based on the absorption spectrum measurement and multi-spot measurement. This paper focuses on the structural design of the system and the establishment of the spectral analysis method. The model of after-spectrophotometric structure is adopted by the detector. The entire hardware platform is implemented based on S3C44B0 & ?C/OS-II embedded system. In addition, this paper puts forward a recognition model, that combines Principal Component Analysis (PCA) with BP Artificial Neural Networks (BPANN), and an algorithm for trace concentration measurement, based on visible light absorption spectrum analysis. The experimental results show that the correct rate of prediction for 50 unknown samples is 98%, and the maximum relative measuring error is 3%.
Liao, Hai-Yang; Tian, Peng
DALI2: A NaI(Tl) detector array for measurements of ? rays from fast nuclei
NASA Astrophysics Data System (ADS)
A NaI(Tl) detector array called DALI2 (Detector Array for Low Intensity radiation 2) has been constructed for in-beam ?-ray spectroscopy experiments with fast radioactive isotope (RI) beams. It consists typically of 186 NaI(Tl) scintillators covering polar angles from ~15� to ~160� with an average angular resolution of 6� in full width at half maximum. Its high granularity (good angular resolution) enables Doppler-shift corrections that result in, for example, 10% energy resolution and 20% full-energy photopeak efficiency for 1-MeV ? rays emitted from fast-moving nuclei (velocities of v/c?0.6). DALI2 has been employed successfully in numerous experiments using fast RI beams with velocities of v/c=0.3-0.6 provided by the RIKEN RI Beam Factory.
Takeuchi, S.; Motobayashi, T.; Togano, Y.; Matsushita, M.; Aoi, N.; Demichi, K.; Hasegawa, H.; Murakami, H.
Infrared absorption spectroscopy of solid propellant flames using a Pt-Si array detector
NASA Astrophysics Data System (ADS)
A multichannel infrared absorption technique has been developed and applied to the study of solid propellant flames. Infrared absorption spectra of HCN, H2CO, CH4, CO, CO2, N2O, and H2O have been obtained in the dark zone of solid propellant flames during steady state combustion conditions through the use of a 1024 element platinum silicide (Pt-Si) array detector. The experiment consists of a quartz tungsten halogen lamp as the source, a 0.320 m spectrometer with a 75 grooves/mm grating, the Pt-Si array detector and a windowed strand burner where cylindrical propellant samples are burned cigarette fashion in the presence of an inert buffer gas. Results for a nitramine propellant M43 are presented along with estimates for the temperature and species concentrations through the use of the HITRAN database and associated PC programs.
Modiano, Steven H.; Vanderhoff, John A.
Automated characterization of single-photon avalanche photodiode
We report an automated characterization of a single-photon detector based on commercial silicon avalanche photodiode (PerkinElmer C30902SH). The photodiode is characterized by I-V curves at different illumination levels (darkness, 10 pW and 10 uW), dark count rate and photon detection efficiency at different bias voltages. The automated characterization routine is implemented in C++ running on a Linux computer.
Aina M. M. Ghazali; Audun N. Bugge; Sebastien Sauge; Vadim Makarov
The Cosmology Large Angular Scale Surveyor (CLASS): 38 GHz detector array of bolometric polarimeters
The Cosmology Large Angular Scale Surveyor (CLASS) experiment aims to map the polarization of the Cosmic Microwave Background (CMB) at angular scales larger than a few degrees. Operating from Cerro Toco in the Atacama Desert of Chile, it will observe over 65% of the sky at 38, 93, 148, and 217 GHz. In this paper we discuss the design, construction, and characterization of the CLASS 38 GHz detector focal plane, the first ever Q-band bolometric polarimeter array.
Appel, John W; Amiri, Mandana; Araujo, Derek; Bennett, Charles L; Boone, Fletcher; Chan, Manwei; Cho, Hsiao-Mei; Chuss, David T; Colazo, Felipe; Crowe, Erik; Denis, Kevin; Dunner, Rolando; Eimer, Joseph; Essinger-Hileman, Thomas; Gothe, Dominik; Halpern, Mark; Harrington, Kathleen; Hilton, Gene; Hinshaw, Gary F; Huang, Caroline; Irwin, Kent; Jones, Glenn; Karakla, John; Kogut, Alan J; Larson, David; Limon, Michele; Lowry, Lindsay; Marriage, Tobias; Mehrle, Nicholas; Miller, Amber D; Miller, Nathan; Moseleyb, Samuel H; Novakh, Giles; Reintsemad, Carl; Rostemab, Karwan; Stevensonb, Thomas; Towner, Deborah; U-Yen, Kongpop; Wagner, Emily; Watts, Duncan; Wollack, Edward; Xu, Zhilei; Zeng, Lingzhen
High-resolution SPECT with a CdZnTe detector array and a scintillation camera
The emerging significance of transgenic animal research has motivated the development of radionuclide imaging systems for mice and other small animals. In this work we compare the performance of a scintillation camera with a pinhole collimator (aperture diameter = 0.5 mm, magnification = 8-10) to that of a pixellated CdZnTe hybrid detector array with a parallel-hole collimator (pixel pitch =
M. C. Wu; G. A. Kastis; S. J. Balzer; D. W. Wilson; H. B. Barber; H. H. Barrett; M. W. Dae; B. H. Hasegawa
Development of an intraoperative gamma camera based on a 256-pixel mercuric iodide detector array
A 256-element mercuric iodide (HgI2) detector array has been developed which is intended for use as an intraoperative gamma camera (IOGC). The camera is specifically designed for use in imaging gamma-emitting radiopharmaceuticals (such as 99m-Tc labeled Sestamibi) incorporated into brain tumors in the intraoperative surgical environment. The system is intended to improve the success of tumor removal surgeries by allowing
Bradley E. Patt; Martin P. Tornai; Jan S. Iwanczyk; Craig S. Levin; Edward J. Hoffman
Detector arrays for the James Webb Space Telescope near-infrared spectrograph
The James Webb Space Telescope's (JWST) Near Infrared Spectrograph (NIRSpec) incorporates two 5 mum cutoff (lambdaco =5 mum) 2048�2048 pixel Teledyne HgCdTe HAWAII-2RG sensor chip assemblies. These detector arrays, and the two Teledyne SIDECAR application specific integrated circuits that control them, are operated in space at T ~ 37 K. In this article, we provide a brief introduction to NIRSpec,
Bernard J. Rauscher; David Alexander; Clifford K. Brambora; Rebecca Derro; Chuck Engler; Ori Fox; Matthew B. Garrison; Greg Henegar; Robert J. Hill; Thomas Johnson; Don J. Lindler; Sridhar S. Manthripragada; Cheryl Marshall; Brent Mott; Thomas M. Parr; Wayne D. Roher; Kamdin B. Shakoorzadeh; Miles Smith; Augustyn Waczynski; Yiting Wen; Donna Wilson; Wei Xia-Serafino; Craig Cabelli; Edward Cheng; James Garnett; Markus Loose; Majid Zandian; Joseph Zino; Timothy Ellis; Bryan Howe; Mirium Jurado; Ginn Lee; John Nieznanski; Peter Wallis; James York; Michael W. Regan; Georgio Bagnasco; Torsten B�ker; Guido De Marchi; Pierre Ferruit; Peter Jakobsen; Paolo Strada
Focal Plane Array Shutter Mechanism of the JWST NIRSpec Detector System
NASA Technical Reports Server (NTRS)
This viewgraph presentation reviews the requirements, chamber location, shutter system design, stepper motor specifications, dry lubrication, control system, the environmental cryogenic function testing and the test results of the Focal Plane Array Shutter mechanism for the James Webb Space Telescope Near Infrared Spectrum Detector system. Included are design views of the location for the Shutter Mechanism, lubricant (lubricated with Molybdenum Di Sulfide) thickness, and information gained from the cryogenic testing.
Hale, Kathleen; Sharma, Rajeev
Optimization of Compton-suppression and summing schemes for the TIGRESS HPGe detector array
Methods of optimizing the performance of an array of Compton-suppressed, segmented HPGe clover detectors have been developed which rely on the physical position sensitivity of both the HPGe crystals and the Compton-suppression shields. These relatively simple analysis procedures promise to improve the precision of experiments with the TRIUMF-ISAC Gamma-Ray Escape-Suppressed Spectrometer (TIGRESS). Suppression schemes will improve the efficiency and peak-to-total
M. A. Schumaker; C. E. Svensson; C. Andreoiu; A. Andreyev; R. A. E. Austin; G. C. Ball; D. Bandyopadhyay; A. J. Boston; R. S. Chakrawarthy; R. Churchman; T. E. Drake; P. Finlay; P. E. Garrett; G. F. Grinyer; G. Hackman; B. Hyland; B. Jones; R. Maharaj; A. C. Morton; C. J. Pearson; A. A. Phillips; F. Sarazin; H. C. Scraggs; M. B. Smith; J. J. Valiente-Dob�n; J. C. Waddington; L. M. Watters
A multiple-filter F detector method for medium-aperture seismometer arrays
NASA Astrophysics Data System (ADS)
The generalized F method, developed for teleseismic signal detection at small-aperture arrays, is extended to medium-aperture arrays and regional-distance signals using a multiple-filter technique. The technique allows the continuous estimate of the instantaneous amplitude and phase of the array seismograms, while at the same time allowing time-domain beamforming, making the method applicable to situations where the transit time of the signal across an array is much greater than the signal duration. The method is tested by application to waveform data from 22 seismometer arrays of the International Monitoring System, being set up to monitor compliance with the Comprehensive Nuclear-Test-Ban Treaty. A comparison with the results of the traditional signal detection method used by the International Data Centre (IDC) shows that the F detector increases candidate first P associations with IDC Reviewed Event Bulletin events, whereas at the same time halving the overall number of detections. The F method increases the number of associations at 21 of the 22 arrays, and for all signal slownesses.
Selby, Neil D.
A space qualified thermal imaging system using a Pt Si detector array
NASA Technical Reports Server (NTRS)
EDO Corporation, Barnes Engineering Division designed and constructed a high resolution thermal imaging system on contract to Lockheed for use in the SDI Star Lab. This employs a Pt Si CCD array which is sensitive in the spectral range of 3 to 5 microns. Star Lab will be flown in the Shuttle bay and consists basically of a large, reflecting, tracking telescope with associated sensors and electronics. The thermal imaging system is designed to operate in the focal plane of this telescope. The configuration of the system is illustrated. The telescope provides a collimated beam output which is focussed onto the detector array by a silicon objective lens. The detector array subtends a field of view of 1.6 degrees x 1.22 degrees. A beam switching mirror permits bypassing the large telescope to give a field of 4 degrees x 3 degrees. Two 8 position filter wheels are provided, and background radiation is minimized by Narcissus mirrors. The detector is cooled with a Joule-Thompson cryostat fed from a high pressure supply tank. This was selected instead of a more convenient closed-cycle system because of concern with vibration. The latter may couple into the extremely critical Starlab tracking telescope. The electronics produce a digitized video signal for recording. Offset and responsivity correction factors are stored for all pixels and these corrections are made to the digitized output in real time.
Astheimer, Robert W.
Crown detectors arrays to observe horizontal and upward air-showers
NASA Astrophysics Data System (ADS)
Terrestrial Cerenkov Telescopes at tens GeV gamma energy and Scintillators set on a Crown-like array facing the Horizons may reveal far Cosmic Rays Showers or nearer PeVs Neutrino ?-e?W- shower in air as well as up-going ?? + N ? ? + X, ? ? Earth-Skimming tau air-showers. Even UHE SUSY ?o+e?e�??o+e at tens PeVs-EeV energy may blaze at Horizons, as ?-e?W- shower. We show first estimate on down- and up-going Horizontal Showers traces for present and future Magic-like Crown Arrays and their correlated Scintillator-like twin Crown Arrays. The one mono- or stereo-Magic elements facing the Horizons are already comparable to present Amanda underground neutrino detector.
Fargion, D.; Grossi, M.; De Santis, M.; De Sanctis Lucentini, P. G.; Iori, M.; Sergi, A.; Moscato, F.
Detector arrays for photometric measurements at soft X-ray, ultraviolet and visible wavelengths
NASA Technical Reports Server (NTRS)
The construction and modes of operation of the Multi-Anode Microchannel Array (MAMA) detectors are described, and the designs of spectrometers utilizing them are outlined. MAMA consists of a curved microchannel array plate, an opaque photocathode (peak quantum efficiency of 19% at 1216 A), and a multi-anode (either discrete- or coincidence-anode) readout array. Designed for use in instruments on spaceborne telescopes, MAMA can be operated in a windowless configuration in extreme-ultraviolet and soft X-ray wavelengths, or in a sealed configuration at UV and visible wavelengths. Advantages of MAMA include low applied potential (less than 3.0 kV), high gain (greater than 10 to the 6th electrons/pulse), low sensitivity to high-energy charged particles, and immunity to external magnetic fields of less than 500 Gauss
Timothy, J. G.; Mount, G. H.; Bybee, R. L.
The performance of CCD array detectors for application in high-resolution tomography
NASA Astrophysics Data System (ADS)
Charge coupled device arrays (CCDs) with low noise, small pixel size and high charge storage capacity are available at relatively low cost. Because of this, CCDs are finding increasing use in imaging applications. In this paper, the performance of a TI-4849 CCD array in an X-ray camera to be used for high-resolution synchrotron radiation tomography is discussed. The X-ray image is converted to visible light on a phosphor coated optical face plate which is imaged by a thermoelectrically cooled CCD. The measured modulation transfer function (high-contrast MTF) is presented for this system. The procedures for choosing and preparing the optimal phosphors for X-ray imaging are described. Advantages and limitations of CCD arrays over other detectors for tomographic applications are also discussed.
Kinney, J. H.; Johnson, Q. C.; Bonse, U.; Nusshardt, R.; Nichols, M. C.
Microelectrode Arrays with Overlapped Diffusion Layers as Electroanalytical Detectors: Theory and Basic Applications
This contribution contains a survey of basic literature dealing with arrays of microelectrodes with overlapping diffusion layers as prospective tools in contemporary electrochemistry. Photolithographic thin layer technology allows the fabrication of sensors of micrometric dimensions separated with a very small gap. This fact allows the diffusion layers of single microelectrodes to overlap as members of the array. Various basic types of microelectrode arrays with interacting diffusion layers are described and their analytical abilities are accented. Theoretical approaches to diffusion layer overlapping and the consequences of close constitution effects such as collection efficiency and redox cycling are discussed. Examples of basis applications in electroanalytical chemistry such as amperometric detectors in HPLC and substitutional stripping voltammetry are also given. PMID:24152927
Tom?�k, Peter
A large area plastic scintillator detector array for fast neutron measurements
A large area plastic scintillator detector array(~ 1 m x1m) has been set up for fast neutron spectroscopy at the BARC-TIFR Pelletron laboratory, Mumbai. The energy, time and position response has been measured for electrons using radioactive sources and for mono-energetic neutrons using the 7Li(p,n1)7Be*(0.429 MeV) reaction at proton energies between 6.3 and 19 MeV. A Monte Carlo simulation of the energy dependent efficiency of the array for neutron detection is in agreement with the 7Li(p,n1) measurements. The array has been used to measure the neutron spectrum, in the energy range of 4-12 MeV, in the reaction 12C+ 93Nb at E(12C)= 40 MeV. This is in reasonable agreement with a statistical model calculation.
P. C. Rout; D. R. Chakrabarty; V. M. Datar; Suresh Kumar; E. T. Mirgule; A. Mitra; V. Nanal; R. Kujur
Performance of charge-injection-device infrared detector arrays at low and moderate backgrounds
NASA Technical Reports Server (NTRS)
Three 2 x 64 element charge injection device infrared detector arrays were tested at low and moderate background to evaluate their usefulness for space based astronomical observations. Testing was conducted both in the laboratory and in ground based telescope observations. The devices showed an average readout noise level below 200 equivalent electrons, a peak responsivity of 4 A/W, and a noise equivalent power of 3x10 sq root of W/Hz. Array well capacity was measured to be significantly smaller than predicted. The measured sensitivity, which compares well with that of nonintegrating discrete extrinsic silicon photoconductors, shows these arrays to be useful for certain astronomical observations. However, the measured readout efficiency and frequency response represent serious limitations in low background applications.
Mckelvey, M. E.; Mccreight, C. R.; Goebel, J. H.; Reeves, A. A.
Development of a large scale stressed Ge:Ga detector array for SAFARI
NASA Astrophysics Data System (ADS)
We report on the development of a large-format stressed gallium doped germanium (Ge:Ge) array for the SAFARI instrument planned for the Japanese infrared satellite SPICA. Building on flight proven PACS heritage, the goal of our development is a 32 pixel stressed Ge:Ga module for the wavelength range between 110 and 210 ?m, being the building block of a 32 � 32 pixel detector array. The unprecedented size of this array would allow the use of almost all of the 3.8 � 3.8 arcmin field of view available to SAFARI in the SPICA focal plane. Our 32 pixel prototype module features three selectable read-out architectures enabling the evaluation and optimization of the detector performance as well as a two stage multiplexer to distribute the dissipative heat load on the temperature stages provided by the satellite. Thermal modeling has shown that the heat loads are in compliance with the thermal budgets of the SPICA cryogenic system. The ultimate development goal with optimized read-out circuits is an NEP of 1 � 10-18 W/Hz1/2, which presents a factor of 8 improvement in noise performance compared to the PACS stressed Ge:Ga array.
Raab, Walfried; Poglitsch, Albrecht; H�hnle, Rainer; Barl, Lothar
Development of Passively Cooled Long Wave Infrared Detector Arrays for NEOCam
NASA Astrophysics Data System (ADS)
The Near Earth Object Camera (NEOCam) is a proposed space mission designed to discover and characterize most of the potentially hazardous asteroids that orbit near the Earth. NEOCam consists of an infrared telescope and a passively cooled wide-field camera operating at thermal infrared wavelengths. NASA has funded technology development for NEOCam, including the development of long wavelength infrared detector arrays that will have excellent performance at NEOCam�s zodiacal emission-limited background. Teledyne Imaging Sensors has developed and delivered for test at the University of Rochester the first set of approximately 10 micron cutoff, 1024 x 1024 HgCdTe detector arrays in accord with NEOCam requirements. The first measurements of these arrays show the development to be extremely promising: noise, dark current, quantum efficiency and well depth goals have been met by this technology at focal plane temperatures of 40K, readily attainable with passive cooling. The next set of arrays to be developed will address changes suggested by the first set of deliverables.
McMurtry, Craig W.; Lee, D.; Beletic, J.; Chen, C.; Demers, R.; Dorn, M.; Edwall, D.; Bacon Fazar, C.; Forrest, W. J.; Liu, F.; Mainzer, A. K.; Pipher, J.; Yulius, A.
Hybrid UV Imager Containing Face-Up AlGaN/GaN Photodiodes
NASA Technical Reports Server (NTRS)
A proposed hybrid ultraviolet (UV) image sensor would comprise a planar membrane array of face-up AlGaN/GaN photodiodes integrated with a complementary metal oxide/semiconductor (CMOS) readout-circuit chip. Each pixel in the hybrid image sensor would contain a UV photodiode on the AlGaN/GaN membrane, metal oxide/semiconductor field-effect transistor (MOSFET) readout circuitry on the CMOS chip underneath the photodiode, and a metal via connection between the photodiode and the readout circuitry (see figure). The proposed sensor design would offer all the advantages of comparable prior CMOS active-pixel sensors and AlGaN UV detectors while overcoming some of the limitations of prior (AlGaN/sapphire)/CMOS hybrid image sensors that have been designed and fabricated according to the methodology of flip-chip integration. AlGaN is a nearly ideal UV-detector material because its bandgap is wide and adjustable and it offers the potential to attain extremely low dark current. Integration of AlGaN with CMOS is necessary because at present there are no practical means of realizing readout circuitry in the AlGaN/GaN material system, whereas the means of realizing readout circuitry in CMOS are well established. In one variant of the flip-chip approach to integration, an AlGaN chip on a sapphire substrate is inverted (flipped) and then bump-bonded to a CMOS readout circuit chip; this variant results in poor quantum efficiency. In another variant of the flip-chip approach, an AlGaN chip on a crystalline AlN substrate would be bonded to a CMOS readout circuit chip; this variant is expected to result in narrow spectral response, which would be undesirable in many applications. Two other major disadvantages of flip-chip integration are large pixel size (a consequence of the need to devote sufficient area to each bump bond) and severe restriction on the photodetector structure. The membrane array of AlGaN/GaN photodiodes and the CMOS readout circuit for the proposed image sensor would be fabricated separately.
Zheng, Xinyu; Pain, Bedabrata
Charge-coupled-device/fiberoptic taper array X-ray detector for protein crystallography
A large area, charge-couple-device (CCD) based fiberoptic taper array detector (APS-1) has been installed at the insertion-device beamline of the Structural Biology Center at the ANL Advanced Photon Source. The detector is used in protein crystallography diffraction experiments, where the objective is to measure the position and intensity of X-ray Bragg peaks in diffraction images. Large imaging area, very high spatial resolution, high X-ray sensitivity, good detective quantum efficiency, low noise, wide dynamic range, excellent stability and short readout time are all fundamental requirements in this application. The APS-1 detector converts the two-dimensional X-ray patterns to a visible light images by a thin layer of X-ray sensitive phosphor. The phosphor coating is directly deposited on the large ends of nine fiberoptic tapers arranged in a 3x3 array. Nine, thermoelectrically cooled 1024 x 1024 pixel CCD`s image the patterns, demagnified by the tapers. After geometrical and uniformity corrections, the nine areas give a continuous image of the detector face with virtually no gaps between the individual tapers. The 18 parallel analog signal-processing channels and analog-to-digital converters assure short readout time and low readout noise.
Naday, I.; Ross, S.; Westbrook, E.M.; Zentai, G.
Pixel Array Detector for Time-Resolved X-ray Science, September 1, 1997 - September 14, 2000
Progress on the design, fabrication, testing and assembly of two-layer Pixel Array Detectors (PADs) is described. The PADs are developed for challenging time-resolved X-ray imaging applications at synchrotron radiation X-ray sources.
Gruner, Sol M.
Numerical Simulation of the Modulation Transfer Function in HgCdTe Detector Arrays
NASA Astrophysics Data System (ADS)
In this work, we develop a method for simulating the modulation transfer function (MTF) of infrared detector arrays, which is based on numerical evaluation of the detector physics. The finite-difference time-domain and finite element methods are used to solve the electromagnetic and electrical equations for the device, respectively. We show how the total MTF can be deconvolved to examine the effects of specific physical processes. We introduce the MTF area difference and use it to quantify the effectiveness of several crosstalk mitigation techniques in improving the system MTF. We then apply our simulation methods to two-thirds generation mercury cadmium telluride (HgCdTe) detector architectures. The methodology is general, can be implemented with commercially available software, has experimentally realizable analogs, and is extendable to other material systems and device designs.
Pinkie, Benjamin; Bellotti, Enrico
X-ray analog pixel array detector for single synchrotron bunch time-resolved imaging
Dynamic X-ray studies can reach temporal resolutions limited by only the X-ray pulse duration if the detector is fast enough to segregate synchrotron pulses. An analog integrating pixel array detector with in-pixel storage and temporal resolution of around 150?ns, sufficient to isolate pulses, is presented. Analog integration minimizes count-rate limitations and in-pixel storage captures successive pulses. Fundamental tests of noise and linearity as well as high-speed laser measurements are shown. The detector resolved individual bunch trains at the Cornell High Energy Synchrotron Source at levels of up to 3.7 � 103?X-rays per pixel per train. When applied to turn-by-turn X-ray beam characterization, single-shot intensity measurements were made with a repeatability of 0.4% and horizontal oscillations of the positron cloud were detected. PMID:21335901
Koerner, Lucas J.; Gruner, Sol M.
Real-time scintillation array dosimetry for radiotherapy: The advantages of photomultiplier detectors
Purpose: In this paper, a photomultiplier tube (PMT) array dosimetry system has been developed and tested for the real-time readout of multiple scintillation signals from fiber optic dosimeters. It provides array dosimetry with the advantages in sensitivity provided by a PMT, but without the need for a separate PMT for each detector element. Methods: The PMT array system consisted of a multianode PMT, a multichannel data acquisition system, housing and optic fiber connections suitable for clinical use. The reproducibility, channel uniformity, channel crosstalk, acquisition speed, and sensitivity of the PMT array were quantified using a constant light source. Its performance was compared to other readout systems used in scintillation dosimetry. An in vivo HDR brachytherapy treatment was used as an example of a clinical application of the dosimetry system to the measurement of dose at multiple sites in the rectum. The PMT array system was also tested in the pulsed beam of a linear accelerator to test its response speed and its application with two separate methods of Cerenkov background removal. Results: The PMT array dosimetry system was highly reproducible with a measurement uncertainty of 0.13% for a 10 s acquisition period. Optical crosstalk between neighboring channels was accounted for by omitting every second channel. A mathematical procedure was used to account for the crosstalk in next-neighbor channels. The speed and sensitivity of the PMT array system were found be superior to CCD cameras, allowing for measurement of more rapid changes in dose rate. This was further demonstrated by measuring the dose delivered by individual photon pulses of a linear accelerator beam. Conclusions: The PMT array system has advantages over CCD camera-based systems for the readout of scintillation light. It provided a more sensitive, more accurate, and faster response to meet the demands of future developments in treatment delivery.
Liu, Paul Z. Y.; Suchowerska, Natalka; Abolfathi, Peter; McKenzie, David R. [School of Physics, University of Sydney, New South Wales 2006, Australia and Department of Radiation Oncology, Royal Prince Alfred Hospital, Camperdown, New South Wales 2050 (Australia); School of Physics, University of Sydney, New South Wales 2006 (Australia)
Lung counting: comparison of detector performance with a four detector array that has either metal or carbon fibre end caps, and the effect on mda calculation.
This study described the performance of an array of high-purity Germanium detectors, designed with two different end cap materials-steel and carbon fibre. The advantages and disadvantages of using this detector type in the estimation of the minimum detectable activity (MDA) for different energy peaks of isotope (152)Eu were illustrated. A Monte Carlo model was developed to study the detection efficiency for the detector array. A voxelised Lawrence Livermore torso phantom, equipped with lung, chest plates and overlay plates, was used to mimic a typical lung counting protocol with the array of detectors. The lung of the phantom simulated the volumetric source organ. A significantly low MDA was estimated for energy peaks at 40 keV and at a chest wall thickness of 6.64 cm. PMID:22355171
Ahmed, Asm Sabbir; Hauck, Barry; Kramer, Gary H
Micro-mirror arrays for spectroscopic applications
NASA Astrophysics Data System (ADS)
Visible and Near Infrared (NIR) spectroscopy finds use in a number of applications including security, biomedicine, military, materials science, and materials processing areas to name a few. Visible red and NIR ranges are particularly valuable for in vivo studies because photons in this range have very low potential energy and are hence usually considered noninvasive. Integrated spectrometers operating in the NIR spectral range can have high resolution and transmission, low cost, and can exhibit low noise depending on detection properties and light throughput. Optical and NIR spectrometers in this and other work have been shown to operate under normal environmental conditions (such as temperature, atmospheric gases, and humidity) and do not generally require vacuum operation. In this research, the "spectral analysis" sections of a micro-mirror based Reflective Adaptive Slit (RAS) with single InGaAs photodiode spectrometer has been studied and compared to a conventional InGaAs array detector based spectrometer. It should be noted that in both approach, either RAS with single photodiode or Conventional Array Detector (CAD) based spectrometry, the spectrometer system requires a dispersive element (prism or grating) or filter to separate the polychromatic light beam under analysis. If the system is a so called "active" system, a light source is also needed. In this work we test, model, and compare a Reflective Adaptive Slit micro-mirror based single element photodiode system to a commercial array detector based spectrometer. Within the context of the Reflective single photodiode micro-mirror Slit spectrometer, we are establishing a set of optical requirements to ideally cover a number of applications. In addition to experimental performance comparisons between the spectrometer approaches, we will report on the performance requirements and environmental issues for these NIR spectrometers.
Duncan, W. M.; Maxwell, C. J.
Calibration of a detector array through beam profile reconstruction with error-locking.
An iterative method is proposed to calibrate radiation sensitivities of an arbitrary two-dimensional (2D) array of detectors. The array is irradiated with a wide open- field beam at the central position, as well as at laterally and longitudinal shifted positions; the 2D beam profile of the wide field is reconstructed iteratively from the ratios of shifted images to the central image. The propagation errors due to output variation and inaccurate array positioning are estimated and removed from the reconstructed beam profile by an error-locking scheme with narrow open-field irradiations. The beam profile is interpolated when necessary and then compared to raw detector responses to determine sensitivities. Two additional methods were implemented for comparison: 1) the commercial iterative calibration method for MapCHECK2 with translation and rotation operations; 2) a labor-intensive noniterative method without the issue of error propagation. A MapCHECK2 2D detector array was used to validate the proposed method with the 6 MV photon beam from a Varian iX linear accelerator. All calibration methods were repeated three times. A total of 5, 9, and 29 irradiations were required to implement the commercial method, the proposed method and the noniterative method respec- tively. Moreover, a 5 mm positioning error was intentionally introduced into the calibration procedures of the commercial and the proposed method to test their robustness. Under the normal operation condition of the linear accelerator and with careful alignment of the MapCHECK2, the deviations of the calibrated sensitivities of the proposed method and commercial method with respect to the noniterative method were 0.30% � 0.29% and 0.92% � 0.63% respectively; when the 5 mm positioning error was presented, these two methods resulted in deviations of 0.40% � 0.36% and 3.58% � 1.94%, respectively. A patient study suggested that, due to this 5 mm positioning error, the mean DTA (dose to agreement) passing rate by the commercial method was 2.7% lower than that by the noniterative method, whereas the proposed method led to a comparable passing rate. It is evident from this study that the proposed iterative method leads to within 1% mean calibration results to established methods. It requires much fewer number of measurements than noniterative method and is more robust against the positioning error than the commercial iterative method. The method also eliminates the need of rotation operations and, therefore, is applicable to inline detector arrays without rotation function, such as electronic portal imager device (EPID).� PMID:25493504
Wang, Song; Li, Zhiqiu; Chao, K S Clifford; Chang, Jenghwa
Photon Counting Energy Dispersive Detector Arrays for X-ray Imaging
The development of an innovative detector technology for photon-counting in X-ray imaging is reported. This new generation of detectors, based on pixellated cadmium telluride (CdTe) and cadmium zinc telluride (CZT) detector arrays electrically connected to application specific integrated circuits (ASICs) for readout, will produce fast and highly efficient photon-counting and energy-dispersive X-ray imaging. There are a number of applications that can greatly benefit from these novel imagers including mammography, planar radiography, and computed tomography (CT). Systems based on this new detector technology can provide compositional analysis of tissue through spectroscopic X-ray imaging, significantly improve overall image quality, and may significantly reduce X-ray dose to the patient. A very high X-ray flux is utilized in many of these applications. For example, CT scanners can produce ~100 Mphotons/mm2/s in the unattenuated beam. High flux is required in order to collect sufficient photon statistics in the measurement of the transmitted flux (attenuated beam) during the very short time frame of a CT scan. This high count rate combined with a need for high detection efficiency requires the development of detector structures that can provide a response signal much faster than the transit time of carriers over the whole detector thickness. We have developed CdTe and CZT detector array structures which are 3 mm thick with 16�16 pixels and a 1 mm pixel pitch. These structures, in the two different implementations presented here, utilize either a small pixel effect or a drift phenomenon. An energy resolution of 4.75% at 122 keV has been obtained with a 30 ns peaking time using discrete electronics and a 57Co source. An output rate of 6�106 counts per second per individual pixel has been obtained with our ASIC readout electronics and a clinical CT X-ray tube. Additionally, the first clinical CT images, taken with several of our prototype photon-counting and energy-dispersive detector modules, are shown. PMID:19920884
Iwanczyk, Jan S.; Nyg�rd, Einar; Meirav, Oded; Arenson, Jerry; Barber, William C.; Hartsough, Neal E.; Malakhov, Nail; Wessel, Jan C.
Array detector for high energy laser based on diffuse transmission sampling
In order to improve the ability and accuracy of measuring the temporal�spatial distribution of the intensity of a large-size, high-energy laser beam, a novel array detecting method based on diffuse transmission sampling is proposed. The measurement principle and the design of the sampling and attenuating unit are presented. High-temperature-resistant diffuse transmission material is used to sample and attenuate a high energy laser beam. Pure copper, whose surface is first sand-blasted and then gold-plated, is applied to scatter the incident high-energy laser beam. The formula for the attenuation ratio was derived in detail. We developed two large-aperture array detectors with spatial resolution of 5 mm, spatial duty ratio of 20%, and useable angle range of �30� without varying the responsivity, the non-uniformity in the laser profile measurement is below 1%, and the repeatability error in the laser power measurement is approximately 1%. The maximal energy density that the array detector can endure is more than 10 kJ/cm{sup 2}.
Pang, Miao [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China) [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang, 621900 China (China); Key Laboratory of High Energy Laser, CAEP, Mianyang 621900 (China); Rong, Jian [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China)] [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Zhou, Shan; Wu, Juan; Zhang, Wei; Hu, Xiaoyang [Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang, 621900 China (China)] [Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang, 621900 China (China); Fan, Guobin [Key Laboratory of High Energy Laser, CAEP, Mianyang 621900 (China)] [Key Laboratory of High Energy Laser, CAEP, Mianyang 621900 (China)
Population density estimated from locations of individuals on a passive detector array
The density of a closed population of animals occupying stable home ranges may be estimated from detections of individuals on an array of detectors, using newly developed methods for spatially explicit capture�recapture. Likelihood-based methods provide estimates for data from multi-catch traps or from devices that record presence without restricting animal movement ("proximity" detectors such as camera traps and hair snags). As originally proposed, these methods require multiple sampling intervals. We show that equally precise and unbiased estimates may be obtained from a single sampling interval, using only the spatial pattern of detections. This considerably extends the range of possible applications, and we illustrate the potential by estimating density from simulated detections of bird vocalizations on a microphone array. Acoustic detection can be defined as occurring when received signal strength exceeds a threshold. We suggest detection models for binary acoustic data, and for continuous data comprising measurements of all signals above the threshold. While binary data are often sufficient for density estimation, modeling signal strength improves precision when the microphone array is small.
Efford, Murray G.; Dawson, Deanna K.; Borchers, David L.
A new detector for mass spectrometry: Direct detection of low energy ions using a multi-pixel photon counter
A new type of ion detector for mass spectrometry and general detection of low energy ions is presented. The detector consists of a scintillator optically coupled to a single-photon avalanche photodiode (SPAD) array. A prototype sensor has been constructed from a LYSO (Lu{sub 1.8}Y{sub 0.2}SiO{sub 5}(Ce)) scintillator crystal coupled to a commercial SPAD array detector. As proof of concept, the detector is used to record the time-of-flight mass spectra of butanone and carbon disulphide, and the dependence of detection sensitivity on the ion kinetic energy is characterised.
Wilman, Edward S.; Gardiner, Sara H.; Vallance, Claire [Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Rd, Oxford OX1 3TA (United Kingdom); Nomerotski, Andrei [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Rd, Oxford OX1 3RH (United Kingdom); Turchetta, Renato [Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom); Brouard, Mark [Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Rd, Oxford OX1 3QZ (United Kingdom)
Multiplexed Intrinsic Detector Arrays with Signal Processing \\/MIDASP\\/ program development of hybrid technology for advanced scanning systems
Systems developed within the framework of the Multiplexed Intrinsic Detector Arrays with Signal Processing (MIDASP) program, which was intended to provide technology necessary for the fabrication of hybrid (Hg, Cd)Te photovoltaic detector\\/silicon signal processor focal planes for second-generation FLIR systems, are discussed. The baseline focal plane design consists of modules each containing about 200 detectors transverse to the scan direction
M. Gurnee; R. Rawe; M. Dries
Majo-ra-na: An Ultra-Low Background Enriched-Germanium Detector Array for Fundamental Physics Measurements
The Majo-ra-na collaboration will search for neutrinoless double-beta decay (0nubetabeta) by fielding an array of high-purity germanium (HPGe) detectors in ultra-clean electroformed-copper cryostats deep underground. Recent advances in HPGe detector technology, in particular P-type Point-Contact (PPC) detectors, present exciting new techniques for identifying and reducing backgrounds to the 0nubetabeta signal. This should result in greatly improved sensitivity over previous generation
Victor Gehman
Temperature Dependence of the EUV Responsivity of Silicon Photodiodes
Responsivity of silicon photodiodes was measured from -100 C to +50 C in the 3 to 250 nm wavelength range using synchrotron and laboratory radiation sources. Two types of silicon photodiodes were studied, the AXUV series having a thin nitrided silicon dioxide surface layer and the SXUV series having a thin metal silicide surface layer. Depending on the wavelength, the responsivity increases with temperature with the rates 0.013%/C to 0.053%/C for the AXUV photodiode and 0.020%/C to 0.084%/C for the SXUV photodiode. The increase in responsivity is consistent with the decrease in the silicon bandgap energy which causes a decrease in the pair creation energy. These results are particularly important for dose measurement in extreme ultraviolet (EUV) lithography steppers and sources since the detector temperature often increases because of the high EUV intensities involved.
Kjornrattanawanich,B.; Korde, R.; Boyer, C.; Holland, G.; Seely, J.
DENSITY: software for analysing capture-recapture data from passive detector arrays
A general computer-intensive method is described for fitting spatial detection functions to capture-recapture data from arrays of passive detectors such as live traps and mist nets. The method is used to estimate the population density of 10 species of breeding birds sampled by mist-netting in deciduous forest at Patuxent Research Refuge, Laurel, Maryland, U.S.A., from 1961 to 1972. Total density (9.9 ? 0.6 ha-1 mean ? SE) appeared to decline over time (slope -0.41 ? 0.15 ha-1y-1). The mean precision of annual estimates for all 10 species pooled was acceptable (CV(D) = 14%). Spatial analysis of closed-population capture-recapture data highlighted deficiencies in non-spatial methodologies. For example, effective trapping area cannot be assumed constant when detection probability is variable. Simulation may be used to evaluate alternative designs for mist net arrays where density estimation is a study goal.
Efford, M.G.; Dawson, D.K.; Robbins, C.S.
Observation of high energy atmospheric neutrinos with antarctic muon and neutrino detector array
The Antarctic Muon and Neutrino Detector Array (AMANDA) began collecting data with ten strings in 1997. Results from the first year of operation are presented. Neutrinos coming through the Earth from the Northern Hemisphere are identified by secondary muons moving upward through the array. Cosmic rays in the atmosphere generate a background of downward moving muons, which are about 10{sup 6} times more abundant than the upward moving muons. Over 130 days of exposure, we observed a total of about 300 neutrino events. In the same period, a background of 1.05 x 10{sup 9} cosmic ray muon events was recorded. The observed neutrino flux is consistent with atmospheric neutrino predictions. Monte Carlo simulations indicate that 90 percent of these events lie in the energy range 66 GeV to 3.4 TeV. The observation of atmospheric neutrinos consistent with expectations establishes AMANDA-B10 as a working neutrino telescope.
Ahrens, J.; Andres, E.; Bai, X.; Barouch, G.; Barwick, S.W.; Bay, R.C.; Becka, T.; Becker, K.-H.; Bertrand, D.; Binon, F.; Biron, A.; Booth, J.; Botner, O.; Bouchta, A.; Bouhali, O.; Boyce, M.M.; Carius, S.; Chen, A.; Chirkin, D.; Conrad, J.; Cooley, J.; Costa, C.G.S.; Cowen, D.F.; Dalberg, E.; De Clercq, C.; DeYoung, T.; Desiati, P.; Dewulf, J.-P.; Doksus, P.; Edsjo, J.; Ekstrom, P.; Feser, T.; Frere, J.-M.; Gaisser, T.K.; Gaug, M.; Goldschmidt, A.; Hallgren, A.; Halzen, F.; Hanson, K.; Hardtke, R.; Hauschildt, T.; Hellwig, M.; Heukenkamp, H.; Hill, G.C.; Hulth, P.O.; Hundertmark, S.; Jacobsen, J.; Karle, A.; Kim, J.; Koci, B.; Kopke, L.; Kowalski, M.; Lamoureux, J.I.; Leich, H.; Leuthold, M.; Lindahl, P.; Liubarsky, I.; Loaiza, P.; Lowder, D.M.; Madsen, J.; Marciniewski, P.; Matis, H.S.; McParland, C.P.; Miller, T.C.; Minaeva, Y.; Miocinovic, P.; Mock, P.C.; Morse, R.; Neunhoffer, T.; Niessen, P.; Nygren, D.R.; Ogelman, H.; Olbrechts, Ph.; Perez de los Heros, C.; Pohl, A.C.; Porrata, R.; Price, P.B.; Przybylski, G.T.; Rawlins, K.; Reed, C.; Rhode, W.; Ribordy, M.; Richter, S.; Rodriguez Martino, J.; Romenesko, P.; Ross, D.; Sander, H.-G.; Schmidt, T.; Schneider, D.; Schwarz, R.; Silvestri, A.; Solarz, M.; Spiczak, G.M.; Spiering, C.; Starinsky, N.; Steele, D.; Steffen, P.; Stokstad, R.G.; Streicher, O.; Sudhoff, P.; Sulanke, K.-H.; Taboada, I.; Thollander, L.; Thon, T.; Tilav, S.; Vander Donckt, M.; Walck, C.; Weinheimer, C.; Wiebusch, C.H.; Wiedeman, C.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Wu, W.; Yodh, G.; Young, S.
Parallel Beam Approximation for Calculation of Detection Efficiency of Crystals in PET Detector Arrays.
In this work we propose a parallel beam approximation for the computation of the detection efficiency of crystals in a PET detector array. In this approximation the detection efficiency of a crystal is estimated using the distance between source and the crystal and the pre-calculated detection cross section of the crystal in a crystal array which is calculated for a uniform parallel beam of gammas. The pre-calculated detection cross sections for a few representative incident angles and gamma energies can be used to create a look-up table to be used in simulation studies or practical implementation of scatter or random correction algorithms. Utilizing the symmetries of the square crystal array, the pre-calculated look-up tables can be relatively small. The detection cross sections can be measured experimentally, calculated analytically or simulated using a Monte Carlo (MC) approach. In this work we used a MC simulation that takes into account the energy windowing, Compton scattering and factors in the "block effect". The parallel beam approximation was validated by a separate MC simulation using point sources located at different positions around a crystal array. Experimentally measured detection efficiencies were compared with Monte Carlo simulated detection efficiencies. Results suggest that the parallel beam approximation provides an efficient and accurate way to compute the crystal detection efficiency, which can be used for estimation of random and scatter coincidences for PET data corrections. PMID:25400292
Komarov, Sergey; Song, Tae Yong; Wu, Heyu; Tai, Yuan-Chuan
Effect of atmospheric turbulence on the bit error probability of a space to ground near infrared laser communications link using binary pulse position modulation and an avalanche photodiode detector
NASA Technical Reports Server (NTRS)
The effect of atmospheric turbulence on the bit error rate of a space-to-ground near infrared laser communications link is investigated, for a link using binary pulse position modulation and an avalanche photodiode detector. Formulas are presented for the mean and variance of the bit error rate as a function of signal strength. Because these formulas require numerical integration, they are of limited practical use. Approximate formulas are derived which are easy to compute and sufficiently accurate for system feasibility studies, as shown by numerical comparison with the exact formulas. A very simple formula is derived for the bit error rate as a function of signal strength, which requires only the evaluation of an error function. It is shown by numerical calculations that, for realistic values of the system parameters, the increase in the bit error rate due to turbulence does not exceed about thirty percent for signal strengths of four hundred photons per bit or less. The increase in signal strength required to maintain an error rate of one in 10 million is about one or two tenths of a db.
Safren, H. G.
Neutron irradiation studies of avalanche photodiodes using californium-252
NASA Astrophysics Data System (ADS)
Californium-252 is a convenient and copious source of neutrons of energies around 1 MeV, and provides many advantages over reactors for neutron irradiation studies of detector components. We describe here an experimental setup at Oak Ridge National Laboratory which has been constructed to study the performance of avalanche photodiodes in neutron fluences up to 10 13 neutrons/cm 2, similar to what is expected in parts of the CMS detector at the LHC. An irradiation study of some avalanche photodiodes is discussed, followed by a brief summary of results obtained.
Reucroft, S.; Rusack, R.; Ruuska, D.; Swain, J.
Intra-pixel response of the new JWST infrared detector arrays
NASA Astrophysics Data System (ADS)
We have repeated some of our previous measurements of the intra-pixel response of the infrared detector arrays for the Fine Guidance Sensor (FGS) instrument on the James Webb Space Telescope (JWST). This set of tests was performed on a 5 micron cutoff substrate-removed HAWAII-1RG from the new batch of devices produced for JWST. The measurements were done at wavelengths from 650 nm to 1550 nm. The results from these tests indicate that there are no significant differences in the intra-pixel response between the older JWST devices and the new ones. Modeling suggests that the primary contributor to the response profile is diffusion in the bulk detector material.
Hardy, T.; Willot, Chris; Pazder, J.
In situ two-dimensional imaging quick-scanning XAFS with pixel array detector
Quick-scanning X-ray absorption fine structure (XAFS) measurements were performed in transmission mode using a PILATUS 100K pixel array detector (PAD). The method can display a two-dimensional image for a large area of the order of a centimetre with a spatial resolution of 0.2?mm at each energy point in the XAFS spectrum. The time resolution of the quick-scanning method ranged from 10?s to 1?min per spectrum depending on the energy range. The PAD has a wide dynamic range and low noise, so the obtained spectra have a good signal-to-noise ratio. PMID:21997918
Tanida, Hajime; Yamashige, Hisao; Orikasa, Yuki; Oishi, Masatsugu; Takanashi, Yu; Fujimoto, Takahiro; Sato, Kenji; Takamatsu, Daiko; Murayama, Haruno; Arai, Hajime; Matsubara, Eiichiro; Uchimoto, Yoshiharu; Ogumi, Zempachi
In situ two-dimensional imaging quick-scanning XAFS with pixel array detector.
Quick-scanning X-ray absorption fine structure (XAFS) measurements were performed in transmission mode using a PILATUS 100K pixel array detector (PAD). The method can display a two-dimensional image for a large area of the order of a centimetre with a spatial resolution of 0.2?mm at each energy point in the XAFS spectrum. The time resolution of the quick-scanning method ranged from 10?s to 1?min per spectrum depending on the energy range. The PAD has a wide dynamic range and low noise, so the obtained spectra have a good signal-to-noise ratio. PMID:21997918
Tanida, Hajime; Yamashige, Hisao; Orikasa, Yuki; Oishi, Masatsugu; Takanashi, Yu; Fujimoto, Takahiro; Sato, Kenji; Takamatsu, Daiko; Murayama, Haruno; Arai, Hajime; Matsubara, Eiichiro; Uchimoto, Yoshiharu; Ogumi, Zempachi
Digital Electronics For The Versatile Array Of Neutron Detectors At Low Energies
A {chi}{sup 2} minimization algorithm has been developed to extract sub-sampling-time information from digitized waveforms, to be used to instrument the future Versatile Array of Neutron Detectors at Low energies. The algorithm performance has been characterized with a fast Arbitrary Function Generator, obtaining time resolution better than 1 ns for signals of amplitudes between 50 mV and 1V, with negligible walk in the whole range. The proof-of-principle measurement of the beta-delayed neutron emission from {sup 89}Br indicates a resolution of 1 ns can be achieved in realistic experimental conditions.
Madurga, M.; Paulauskas, S.; Grzywacz, R.; Padgett, S. W.; Liddick, S. N. [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Bardayan, D. W. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Batchelder, J. C.; Matei, C.; Peters, W. A.; Rasco, C. [Oak Ridge Associated Universities, Oak Ridge, TN 37831 (United States); Blackmon, J. C. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 708034 (United States); Cizewski, J. A.; O'Malley, P. [Department of Physics and Astronomy, Rutgers University, New Brunswick, NJ 08903, US (Canada); Goans, R. E. [Oak Ridge Associated Universities, Oak Ridge, TN 37831 (United States); Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Raiola, F.; Sarazin, F. [Department of Physics, Colorado School of Mines, Golden, CO 80401 (United States)
On-board compensation for temporal changes in pushbroom scanner detector arrays
NASA Technical Reports Server (NTRS)
The design and operation of pushbroom and mechanical scanners are reviewed in order to determine differences in data preprocessing. Data preprocessing is categorized into spatial registration and radiometric corrections, as well as into systematic versus nonsystematic corrections. The category of nonsystematic radiometric errors due to temporal changes in detector array properties is emphasized as a subject of special interest and a challenging problem for onboard data preprocessing. Concepts for onboard compensation of temporal changes are presented. In particular one concept which uses dark current as an indicator of temperature change for determining gain and offset corrections is shown to have a number of advantages.
Jobson, D. J.
The Telescope Array (TA) collaboration has measured the energy spectrum of ultra-high energy cosmic rays (UHECRs) with primary energies above 1.6 Multiplication-Sign 10{sup 18} eV. This measurement is based upon four years of observation by the surface detector component of TA. The spectrum shows a dip at an energy of 4.6 Multiplication-Sign 10{sup 18} eV and a steepening at 5.4 Multiplication-Sign 10{sup 19} eV which is consistent with the expectation from the GZK cutoff. We present the results of a technique, new to the analysis of UHECR surface detector data, that involves generating a complete simulation of UHECRs striking the TA surface detector. The procedure starts with shower simulations using the CORSIKA Monte Carlo program where we have solved the problems caused by use of the ''thinning'' approximation. This simulation method allows us to make an accurate calculation of the acceptance of the detector for the energies concerned.
Abu-Zayyad, T.; Allen, M.; Anderson, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Hanlon, W. [High Energy Astrophysics Institute and Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah (United States); Aida, R. [University of Yamanashi, Interdisciplinary Graduate School of Medicine and Engineering, Kofu, Yamanashi (Japan); Azuma, R.; Fukuda, T. [Graduate School of Science and Engineering, Tokyo Institute of Technology, Meguro, Tokyo (Japan); Cheon, B. G.; Cho, E. J. [Department of Physics and Research Institute of Natural Science, Hanyang University, Seongdong-gu, Seoul (Korea, Republic of); Chiba, J. [Department of Physics, Tokyo University of Science, Noda, Chiba (Japan); Chikawa, M. [Department of Physics, Kinki University, Higashi Osaka, Osaka (Japan); Cho, W. R. [Department of Physics, Yonsei University, Seodaemun-gu, Seoul (Korea, Republic of); Fujii, H. [Institute of Particle and Nuclear Studies, KEK, Tsukuba, Ibaraki (Japan); Fujii, T. [Graduate School of Science, Osaka City University, Osaka, Osaka (Japan); Fukushima, M. [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba (Japan); and others
Charge State Measurements with Photocell Detectors
NASA Astrophysics Data System (ADS)
Measuring charge state distributions (CSD) of few electron systems, like lithium, through various targets can provide information to fill gaps in existing models. There is a need to look at target and ion velocity dependence for few electron systems and compare them with heavy ion interactions. Ultimately, there is a scientific need to probe the interactions between ion and target in order to understand the influences that each have on one another. The development, building, and characterizing of a photodiode array creates an effective tool for making measurements in ion beam experiments. Photodiodes as detectors provide distinct advantages over conventional silicon detectors in a laboratory setting. They are less sensitive to radiation damage, cost effective, easily replaceable, and a valuable teaching tool for undergraduates and graduate students alike. Other than a teaching tool their immediate experimental application will be as a beam monitor. The data presented shows test chamber results, the effects of beam induced damaged, and first CSD measurements.
Schmitt, Chris; Carilli, Michael; Collon, Philippe; Heinz, Andreas; Laverne, Jay; Robertson, Daniel; Sullivan, Sean
Three-dimensional numerical simulation of planar P+n heterojunction In0.53Ga0.47As photodiodes in dense arrays part II: modulation transfer function modeling
NASA Astrophysics Data System (ADS)
Processing improvements have facilitated manufacturing reduced pixel dimensions for lattice-matched InGaAs on InP short-wave infrared detectors. Due to its technological maturity, this material system continues to garner attention for low-light level imaging applications. With pixel dimensions smaller than minority carrier diffusion lengths, optimizing array performance by reducing crosstalk from lateral carrier diffusion remains an important design issue. Analytical models, however, have provided limited insight on underlying mechanisms limiting device performance in the conventional planar double heterointerface device. Quantitative modeling provides tools to investigate performance sensitivities and their underlying mechanisms. In this work we develop a three-dimensional numerical simulation for dense P+n In0.53Ga0.47As on InP photo detector focal plane arrays using a conventional planar, back-illuminated structure. We evaluate optical generation with finite-difference time-domain analysis, and model carrier transport in a drift diffusion analysis simultaneously solving the carrier continuity and Poisson equations. Using this model we investigate modulation transfer function variations with pixel pitch and diffused junction geometries for small dimension arrays. By accounting for carrier diffusion effects, these results should provide a benchmark against which to evaluate modulation transfer function contributions from other effects, such as crosstalk attributable to photon recycling.
Wichman, Adam R.; DeWames, Roger E.; Bellotti, Enrico
A 2-D Array of Superconducting Magnesium Diboride (MgB2) Far-IR Thermal Detectors for Planetary Exploration
NASA Technical Reports Server (NTRS)
A 2-D array of superconducting Magnesium Diboride(MgB2) far IR thermal detectors has been fabricated. Such an array is intended to be at the focal plane of future generation thermal imaging far-IR instruments that will investigate the outer planets and their icy moons. Fabrication and processing of the pixels of the array as well as noise characterization of architectured MgB2 thin films will be presented. Challenges and solutions for improving the performance of the array will be discussed.
Lakew, Brook
Enhanced radiation detectors using luminescent materials
A radiation detecting device comprising a radiation sensing element, and a layer of luminescent material to expand the range of wavelengths over which the sensing element can efficiently detect radiation. The luminescent material being selected to absorb radiation at selected wavelengths, causing the luminescent material to luminesce, and the luminescent radiation being detected by the sensing element. Radiation sensing elements include photodiodes (singly and in arrays), CCD arrays, IR detectors and photomultiplier tubes. Luminescent materials include polymers, oligomers, copolymers and porphyrines, Luminescent layers include thin films, thicker layers, and liquid polymers.
Vardeny, Zeev V. (Holladay, UT); Jeglinski, Stefan A. (Durham, NC); Lane, Paul A. (Sheffield, GB)
An improved high performance liquid chromatography-photodiode array detection-atmospheric pressure chemical ionization-mass spectrometry method for determination of chlorophylls and their derivatives in freeze-dried and hot-air-dried Rhinacanthus nasutus (L.) Kurz.
Rhinacanthus nasutus (L.) Kurz, a traditional Chinese herb possessing antioxidant and anti-cancer activities, has been reported to contain functional components like carotenoids and chlorophylls. However, the variety and amount of chlorophylls remain uncertain. The objectives of this study were to develop a high performance liquid chromatography-photodiode array detection-atmospheric pressure chemical ionization-mass spectrometry (HPLC-DAD-APCI-MS) method for determination of chlorophylls and their derivatives in hot-air-dried and freeze-dried R. nasutus. An Agilent Eclipse XDB-C18 column and a gradient mobile phase composed of methanol/N,N-dimethylformamide (97:3, v/v), acetonitrile and acetone were employed to separate internal standard zinc-phthalocyanine plus 12 cholorophylls and their derivatives within 21 min, including chlorophyll a, chlorophyll a', hydroxychlorophyll a, 15-OH-lactone chlorophyll a, chlorophyll b, chlorophyll b', hydroxychlorophyll b, pheophytin a, pheophytin a', hydroxypheophytin a, hydroxypheophytin a' and pheophytin b in hot-air-dried R. nasutus with flow rate at 1 mL/min and detection at 660 nm. But, in freeze-dried R. nasutus, only 4 chlorophylls and their derivatives, including chlorophyll a, chlorophyll a', chlorophyll b and pheophytin a were detected. Zinc-phthalocyanine was found to be an appropriate internal standard to quantify all the chlorophyll compounds. After quantification by HPLC-DAD, both chlorophyll a and pheophytin a were the most abundant in hot-air-dried R. nasutus, while in freeze-dried R. nasutus, chlorophyll a and chlorophyll b dominated. PMID:22063550
Kao, Tsai Hua; Chen, Chia Ju; Chen, Bing Huei
Development of novel on-chip, customer-design spiral biasing adaptor on for Si drift detectors and detector arrays for X-ray and nuclear physics experiments
NASA Astrophysics Data System (ADS)
A novel on-chip, customer-design spiral biasing adaptor (SBA) has been developed. A single SBA is used for biasing a Si drift detector (SDD) and SDD array. The use of an SBA reduces the biasing current. This paper shows the calculation of the geometry of an SBA and an SDD to get the best drift field in the SDD and SDD array. Prototype SBAs have been fabricated to verify the concept. Electrical measurements on these SBAs are in agreement with the expectations. The new SDD array with an SBA can be used for X-ray detection and in nuclear physics experiments.
Li, Zheng; Chen, Wei
Photon-number-resolving detector with 10 bits of resolution
A photon-number-resolving detector with single-photon resolution is described and demonstrated. It has 10 bits of resolution, does not require cryogenic cooling, and is sensitive to near ir wavelengths. This performance is achieved by flood illuminating a 32x32 element In{sub x}Ga{sub 1-x}AsP Geiger-mode avalanche photodiode array that has an integrated counter and digital readout circuit behind each pixel.
Jiang, Leaf A.; Dauler, Eric A.; Chang, Joshua T
Inkjet-printed organic photodiodes
Inkjet-printed organic photodiodes are reported, which eliminate the need for photodiode patterning as compared to other solution-based fabrication techniques. Both interlayer and bulk heterojunction ink formulations are optimized to fabricate diodes with low dark currents of 2?A\\/cm2 and high external quantum efficiencies of 68.5% at ?5V reverse bias. The current�voltage characteristics of the printed devices are competitive with photodiodes fabricated
Samuele Lilliu; Michaela B�berl; Maria Sramek; Sandro F. Tedde; J. Emyr Macdonald; Oliver Hayden
Dark current measurement of Type-II superlattice infrared focal plane array detector
NASA Astrophysics Data System (ADS)
We report the result of a dark current measurement of a Type-II superlattice (T2SL) infrared focal plane array (FPA), which consists of a 6 ?m cutoff T2SL detector array and the readout integration circuit (ROIC) ISC0903 of FLIR Systems. In order to measure the dark current of the FPA, we obtained images with different exposure times in a fully closed cold shield of 77 K. Using the temporal change rate of the output and considering the charge conversion efficiency of the ROIC, we obtained a dark current density with an average value of 4 � 10-5 A/cm2 at a bias of -100 mV. We also compare the result of the FPA dark current measurement with that of a test element group (TEG), which was a single pixel detector, fabricated by the same process as the FPA. The dark current density of the TEG was 3 � 10-6 A/cm2 at a bias of -100 mV, lower than that of the FPA. We discuss the discrepancy between the dark current densities of the FPA and the TEG.
Sakai, Michito; Katayama, Haruyoshi; Murooka, Junpei; Kimata, Masafumi; Iguchi, Yasuhiro
Fast infrared array spectrometer with a thermoelectrically cooled 160-element PbSe detector
NASA Astrophysics Data System (ADS)
A fast infrared array spectrometer (FIAS) with a thermoelectrically cooled 160-element PbSe detector was demonstrated using measurements of instantaneous infrared radiation intensities simultaneously over the 1.8-4.9 ?m wavelength range at a sampling rate of 390 Hz. A three-point second-degree Lagrange interpolation polynomial was constructed to calibrate the FIAS because of the nonlinear response of the infrared array detector to the incident radiation beam. This calibration method gave excellent measurements of blackbody radiation spectra except for a narrow band at wavelength of 4.3 ?m due to absorption by room carbon dioxide, which is one of the two major gas radiation peaks (2.7 and 4.3 ?m) from the lean premixed hydrocarbon/air combustion products in the midinfrared spectrum. Therefore, the absorption coefficient of room carbon dioxide was conveniently measured on site with the blackbody reference source, and was used in the calibration of the FIAS and also in the calculations of the radiation spectra. Blackbody tests showed that this procedure was effective in correcting for the room carbon dioxide absorption in the radiation spectra measured by the FIAS. For an example of its application, the calibrated FIAS was used to measure spectral radiation intensities from three lean premixed laminar flames and a premixed turbulent jet flame for which reference data with a grating spectrometer were available for comparison. The agreement between the FIAS measurements and the reference data was excellent.
Ji, Jun; Gore, Jay P.; Sivathanu, Yudaya R.; Lim, Jongmook
Performance assessment of a 2D array of plastic scintillation detectors for IMRT quality assurance
NASA Astrophysics Data System (ADS)
The purposes of this work are to assess the performance of a 2D plastic scintillation detectors array prototype for quality assurance in intensity-modulated radiation therapy (IMRT) and to determine its sensitivity and specificity to positioning errors of one multileaf collimator (MLC) leaf and one MLC leaf bank by applying the principles of signal detection theory. Ten treatment plans (step-and-shoot delivery) and one volumetric modulated arc therapy plan were measured and compared to calculations from two treatment-planning systems (TPSs) and to radiochromic films. The averages gamma passing rates per beam found for the step-and-shoot plans were 95.8% for the criteria (3%, 2 mm), 97.8% for the criteria (4%, 2 mm), and 98.1% for the criteria (3%, 3 mm) when measurements were compared to TPS calculations. The receiver operating characteristic curves for the one leaf errors and one leaf bank errors were determined from simulations (theoretical upper limits) and measurements. This work concludes that arrays of plastic scintillation detectors could be used for IMRT quality assurance in clinics. The use of signal detection theory could improve the quality of dosimetric verifications in radiation therapy by providing optimal discrimination criteria for the detection of different classes of errors.
Guillot, Mathieu; Gingras, Luc; Archambault, Louis; Beddar, Sam; Beaulieu, Luc
Dosimetric performance and array assessment of plastic scintillation detectors for stereotactic radiosurgery quality assurance
Purpose: To compare the performance of plastic scintillation detectors (PSD) for quality assurance (QA) in stereotactic radiosurgery conditions to a microion-chamber (IC), Gafchromic EBT2 films, 60 008 shielded photon diode (SD) and unshielded diodes (UD), and assess a new 2D crosshair array prototype adapted to small field dosimetry. Methods: The PSD consists of a 1 mm diameter by 1 mm long scintillating fiber (BCF-60, Saint-Gobain, Inc.) coupled to a polymethyl-methacrylate optical fiber (Eska premier, Mitsubishi Rayon Co., Ltd., Tokyo, Japan). Output factors (S{sub c,p}) for apertures used in radiosurgery ranging from 4 to 40 mm in diameter have been measured. The PSD crosshair array (PSDCA) is a water equivalent device made up of 49 PSDs contained in a 1.63 cm radius area. Dose profiles measurements were taken for radiosurgery fields using the PSDCA and were compared to other dosimeters. Moreover, a typical stereotactic radiosurgery treatment using four noncoplanar arcs was delivered on a spherical phantom in which UD, IC, or PSD was placed. Using the Xknife planning system (Integra Radionics Burlington, MA), 15 Gy was prescribed at the isocenter, where each detector was positioned. Results: Output Factors measured by the PSD have a mean difference of 1.3% with Gafchromic EBT2 when normalized to a 10 x 10 cm{sup 2} field, and 1.0% when compared with UD measurements normalized to the 35 mm diameter cone. Dose profiles taken with the PSD crosshair array agreed with other single detectors dose profiles in spite of the presence of the 49 PSDs. Gamma values comparing 1D dose profiles obtained with PSD crosshair array with Gafchromic EBT2 and UD measured profiles shows 98.3% and 100.0%, respectively, of detector passing the gamma acceptance criteria of 0.3 mm and 2%. The dose measured by the PSD for a complete stereotactic radiosurgery treatment is comparable to the planned dose corrected for its SD-based S{sub c,p} within 1.4% and 0.7% for 5 and 35 mm diameter cone, respectively. Furthermore, volume averaging of the IC can be observed for the 5 mm aperture where it differs by as much as 9.1% compared to the PSD measurement. The angular dependency of the UD is also observed, unveiled by an under-response around 2.5% of both 5 and 35 mm apertures. Conclusions: Output Factors and dose profiles measurements performed, respectively, with the PSD and the PSDCA were in agreement with those obtained with the UD and EBT2 films. For stereotactic radiosurgery treatment verification, the PSD gives accurate results compared to the planning system and the IC once the latter is corrected to compensate for the averaging effect of the IC. The PSD provides precise results when used as a single detector or in a dense array, resulting in a great potential for stereotactic radiosurgery QA measurements.
Gagnon, Jean-Christophe; Theriault, Dany; Guillot, Mathieu; Archambault, Louis; Beddar, Sam; Gingras, Luc; Beaulieu, Luc [Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada) and Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec G1R 2J6 (Canada); Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec G1R 2J6 (Canada); Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada) and Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec G1R 2J6 (Canada); Department of Radiation Physics, Unit 94, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States); Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada) and Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec G1R 2J6 (Canada)
Infrared Detector Activities at NASA Langley Research Center
NASA Technical Reports Server (NTRS)
Infrared detector development and characterization at NASA Langley Research Center will be reviewed. These detectors were intended for ground, airborne, and space borne remote sensing applications. Discussion will be focused on recently developed single-element infrared detector and future development of near-infrared focal plane arrays (FPA). The FPA will be applied to next generation space-based instruments. These activities are based on phototransistor and avalanche photodiode technologies, which offer high internal gain and relatively low noise-equivalent-power. These novel devices will improve the sensitivity of active remote sensing instruments while eliminating the need for a high power laser transmitter.
Abedin, M. N.; Refaat, T. F.; Sulima, O. V.; Amzajerdian, F.
STARS/LiBerACE: Segmented silicon and high-purity germanium detector arrays for low-energy nuclear reaction and structure studies
NASA Astrophysics Data System (ADS)
The Silicon Telescope Array for Reaction Studies (STARS) consists of large-area annular double-sided silicon detectors for charged-particle identification. The Livermore Berkeley Array for Collaborative Experiments (LiBerACE) is an array of six Compton-suppressed high-purity germanium Clover detectors for efficient detection of ?-rays. These detector arrays are versatile tools for studies of neutron-induced reaction cross-sections, fission, light neutron-rich nuclei, and other low-energy nuclear physics topics through transfer, fusion, incomplete-fusion, and inelastic-scattering reactions. The STARS and LiBerACE arrays and typical experimental configurations are described in detail.
Lesher, S. R.; Phair, L.; Bernstein, L. A.; Bleuel, D. L.; Burke, J. T.; Church, J. A.; Fallon, P.; Gibelin, J.; Scielzo, N. D.; Wiedeking, M.
Analysis of amatoxins alpha-amanitin and beta-amanitin in toadstool extracts and body fluids by capillary zone electrophoresis with photodiode array detection.
Over 90% of the lethal cases of mushroom toxin poisoning in man are caused by a species of amanita. The amatoxins (especially alpha- and beta-amanitin) found in amanita deserve special attention, because of their high pharmacological potency, their high natural concentration and their high chemical and thermal stability. Measures can be taken to improve the survival rates (aggressive gastroenteric decontamination, liver protection therapy) if the poisoning is diagnosed correctly and as early as possible. The standard assay for alpha-amanitin is a radioimmunoassay (RIA). Among other reagents, this assay uses 125I-labelled alpha-amaintin, which has a low shelf life. The assay is therefore not available at all hospitals and all year round. In this paper, a first attempt to employ capillary zone electrophoresis (CZE) to quantify amatoxins alpha- and beta-amanitin in urine samples of afflicted patients and in toadstool extracts is described. Diode array detection is used for identification of the resolved substances in the electropherogram. An analysis requires 20 min. The detection limit is 1 microgram/ml, i.e., 5 pg absolute. Relative standard deviations are between 1 and 2% for the calibration standards (peak height and area) and ca. 7.5% for the real samples. Advantages of the CZE over the RIA include lower cost, the possibility of quantifying several toxins in one analysis, less consumption of potentially harmful reagents (no radio-labelled substances, no addition of alpha-amanitin as reagent) and, most importantly, all-year-round availability of the assay. The detection limit is still somewhat high and does not cover the entire clinically relevant range. Attempts to lower the detection limit by the necessary order of magnitude are currently under way in our laboratory. These include application of laser-induced fluorescence detection, liquid chromatography-CZE and CZE-mass spectrometry techniques. PMID:8843665
Br�ggemann, O; Meder, M; Freitag, R
THz imaging using Glow Discharge Detector (GDD) focal plane arrays and large aperture quasi optic mirrors
NASA Astrophysics Data System (ADS)
The properties of terahertz (THz) radiation are well known. They penetrate well most nonconducting media; there are no known biological hazards, and atmospheric attenuation and scattering is lower than for visual and IR radiation. Recently we have found that common miniature commercial neon glow discharge detector (GDD) lamps costing typically about 30 cents each exhibit high sensitivity to THz radiation, with microsecond order rise times, thus making them excellent candidates for such focal plane arrays. Based on this technology we designed, built and tested 4X4 and 8X8 GDD focal plane arrays. A line vector of 32 GDD pixels is being designed in order to increase the number of pixels in such arrays and thus the image resolution. Unique large aperture quasi optic mirrors were design and tested experimentally in this work. A new technology of light weight large aperture mirrors is proposed in this work. In this case a metal coating on plastic substrate is demonstrated. According to first experiments this technology proves to reliable with minimal deformation in LAB conditions. THz Images at 100 GHz were taken using this new inexpensive technology with good quality and resolution.
Kopeika, N. S.; Abramovich, A.; Joseph, H.; Rozban, D.; Akram, A.; Levanon, A.; Yadid-Pecht, O.; Belenky, A.; Lineykin, S.
High-performance SPAD array detectors for parallel photon timing applications
NASA Astrophysics Data System (ADS)
Over the past few years there has been a growing interest in monolithic arrays of single photon avalanche diodes (SPAD) for spatially resolved detection of faint ultrafast optical signals. SPADs implemented in planar technologies offer the typical advantages of microelectronic devices (small size, ruggedness, low voltage, low power, etc.). Furthermore, they have inherently higher photon detection efficiency than PMTs and are able to provide, beside sensitivities down to single-photons, very high acquisition speeds. In order to make SPAD array more and more competitive in time-resolved application it is necessary to face problems like electrical crosstalk between adjacent pixel, moreover all the singlephoton timing electronics with picosecond resolution has to be developed. In this paper we present a new instrument suitable for single-photon imaging applications and made up of 32 timeresolved parallel channels. The 32x1 pixel array that includes SPAD detectors represents the system core, and an embedded data elaboration unit performs on-board data processing for single-photon counting applications. Photontiming information is exported through a custom parallel cable that can be connected to an external multichannel TCSPC system.
Rech, I.; Cuccato, A.; Antonioli, S.; Cammi, C.; Gulinatti, A.; Ghioni, M.
Proton irradiation of PACS stressed Ge:Ga detector arrays to simulate L2-orbit conditions
NASA Astrophysics Data System (ADS)
The ESA Herschel space observatory will be launched in 2008 into the Earth-Sun L2 orbit and the three instruments onboard will be exposed to cosmic radiation during the 4 years lifetime of the satellite. To study the impact of ionizing radiation on the Ge:Ga photoconductors of the PACS instrument (Photodetector Array Camera and Spectrometer), we performed a series of irradiation measurements at the cyclotron of the University of Louvain la Neuve, Belgium simulating the in-flight predicted proton fluxes including solar flare events. The PACS integral field spectrometer contains two 25�16 pixel arrays of Ge:Ga crystals: a low stressed configuration is used in the wavelength range from 55 to 105 ?m, and a high stressed device covers the range 105 to 210 ?m. Calibration of the detector modules under realistic IR background fluxes is done at MPE Garching and MPIA Heidelberg. 70 MeV protons were generated at the cyclotron test site. They were attenuated on their way to the detectors by beam conditioning elements and the metal shields of the cryostat before they reached the Ge:Ga crystals with a mean energy of 17 MeV and a standard deviation of 1.5 MeV. According to predictions the expected proton fluxes were set to nominally 10 ps -1cm -2 and to 400 ps -1cm -2 simulating solar flares. We observed radiation-induced glitches in the detector signal, changes in responsivity, increase in noise and transient behavior. The ongoing data evaluation indicates optimal operating parameters, the best curing method and frequency, calibration procedures and data processing algorithms aiming for a high photometric accuracy.
Katterloher, R.; Barl, L.; Poglitsch, A.; Royer, P.; Stegmaier, J.
Fourier transform spectroscopic imaging using an infrared focal-plane array detector.
A powerful new mid-infrared spectroscopic chemical imaging technique combining step-scan Fourier transform Michelson interferometry with indium antimonide focal-plane array (FPA) image detection is described. The coupling of an infrared focal-plane array detector to an interferometer provides an instrumental multiplex/multichannel advantage. Specifically, the multiple detector elements enable spectra at all pixels to be collected simultaneously, while the interferometer portion of the system allows all the spectral frequencies to be measured concurrently. With this method of mid-infrared spectroscopic imaging, the fidelity of the generated spectral images is limited only by the number of pixels on the FPA detector, and only several seconds of starting time is required for spectral image acquisition. This novel, high-definition technique represents the future of infrared chemical imaging analysis, a new discipline within the chemical and material sciences, which combines the capability of spectroscopy for molecular analysis with the power of visualization. In particular, chemical imaging is broadly applicable for noninvasive, molecular characterization of heterogeneous materials, since all solid-state materials exhibit chemical nonuniformity that exists either by design or by development during the course of material preparation or fabrication. Imaging, employing Raman and infrared spectroscopy, allows the precise characterization of the chemical composition, domain structure, and chemical architecture of a variety of substances. This information is often crucial to a wide range of activities, extending from the fabrication of new materials to a basic understanding of biological samples. In this study, step-scan imaging principles, instrument design details, and infrared chemical imaging results are presented. Since the prospect of performing high-resolution and high-definition mid-infrared chemical imaging very rapidly has been achieved with the step-scan approach, the implications for the chemical analysis of materials are many and varied. PMID:8686889
Lewis, E N; Treado, P J; Reeder, R C; Story, G M; Dowrey, A E; Marcott, C; Levin, I W
Non-local means-based nonuniformity correction for infrared focal-plane array detectors
NASA Astrophysics Data System (ADS)
The infrared imaging systems are normally based on the infrared focal-plane array (IRFPA) which can be considered as an array of independent detectors aligned at the focal plane of the imaging system. Unfortunately, every detector on the IRFPA may have a different response to the same input infrared signal which is known as the nonuniformity problem. Then we can observe the fixed pattern noise (FPN) from the resulting images. Standard nonuniformity correction (NUC) methods need to be recalibrated after a short period of time due the temporal drift of the FPN. Scene-based nonuniformity correction (NUC) techniques eliminate the need for calibration by correction coefficients based on the scene being viewed. However, in the scene-based NUC method the problem of ghosting artifacts widely seriously decreases the image quality, which can degrade the performance of many applications such as target detection and track. This paper proposed an improved scene-based method based on the retina-like neural network approach. The method incorporates the use of non-local means (NLM) method into the estimation of the gain and the offset of each detector. This method can not only estimates the accurate correction coefficient but also restrict the ghosting artifacts efficiently. The proposed method relies on the use of NLM method which is a very successful image denoising method. And then the NLM used here can preserve the image edges efficiently and obtain a reliable spatial estimation. We tested the proposed NUC method by applying it to an IR sequence of frames. The performance of the proposed method was compared the other well-established adaptive NUC techniques.
Yu, Hui; Zhang, Zhi-jie; Chen, Fu-sheng; Wang, Chen-sheng
[Research on the neas infrared focal plane array detector imaging technology used in the laser warning].
In order to achieve the incoming laser's accurate position, it is necessary to improve the detected laser's direction resolution. The InGaAs focal plane array detector with the type of FPA-320 x 256-C was selected as the core component of the diffraction grating laser warning device. The detection theory of laser wavelength and direction based on diffraction grating was introduced. The drive circuit was designed through the analysis of the detector's performance and parameters. Under the FPGA' s timing control, the detector's analog output was sampled by the high-speed AD. The data was cached to FPGA's extended SRAM, and then transferred to a PC through USB. Labview on a PC collects the raw data for processing and displaying. The imaging experiments were completed with the above method. With the wavelength of 1550 nm and 980 nm laser from different directions the diffraction images were detected. Through analysis the location of the zero order and one order can be determined. According to the grating diffraction theory, the wavelength and the direction of the two-dimensional angle can be calculated. It indicates that the wavelength error is less than 10 nm, and the angle error is less than 1 degrees. PMID:25007645
Wang, Zhi-Bin; Huang, Yan-Fei; Wang, Yao-Li; Zhang, Rui; Wang, Yan-Chao
Small-angle solution scattering using the mixed-mode pixel array detector
Solution small-angle X-ray scattering (SAXS) measurements were obtained using a 128 � 128 pixel X-ray mixed-mode pixel array detector (MMPAD) with an 860?�s readout time. The MMPAD offers advantages for SAXS experiments: a pixel full-well of >2 � 107 10?keV X-rays, a maximum flux rate of 108?X-rays pixel?1 s?1, and a sub-pixel point-spread function. Data from the MMPAD were quantitatively compared with data from a charge-coupled device (CCD) fiber-optically coupled to a phosphor screen. MMPAD solution SAXS data from lysozyme solutions were of equal or better quality than data captured by the CCD. The read-noise (normalized by pixel area) of the MMPAD was less than that of the CCD by an average factor of 3.0. Short sample-to-detector distances were required owing to the small MMPAD area (19.2?mm � 19.2?mm), and were revealed to be advantageous with respect to detector read-noise. As predicted by the Shannon sampling theory and confirmed by the acquisition of lysozyme solution SAXS curves, the MMPAD at short distances is capable of sufficiently sampling a solution SAXS curve for protein shape analysis. The readout speed of the MMPAD was demonstrated by continuously monitoring lysozyme sample evolution as radiation damage accumulated. These experiments prove that a small suitably configured MMPAD is appropriate for time-resolved solution scattering measurements. PMID:21335900
Koerner, Lucas J.; Gillilan, Richard E.; Green, Katherine S.; Wang, Suntao; Gruner, Sol M.
Development of a unit cell for a Ge:Ga detector array
NASA Technical Reports Server (NTRS)
Two modules of gallium-doped germanium (Ge:Ga) infrared detectors with integrated multiplexing readouts and supporting drive electronics were designed and tested. This development investigated the feasibility of producing two-dimensional Ge:Ga arrays by stacking linear modules in a housing capable of providing uniaxial stress for enhanced long-wavelength response. Each module includes 8 detectors (1x1x2 mm) mounted to a sapphire board. The element spacing is 12 microns. The back faces of the detector elements are beveled with an 18 deg angle, which was proved to significantly enhance optical absorption. Each module includes a different silicon metal-oxide semiconductor field effect transistor (MOSFET) readout. The first circuit was built from discrete MOSFET components; the second incorporated devices taken from low-temperature integrated circuit multiplexers. The latter circuit exhibited much lower stray capacitance and improved stability. Using these switched-FET circuits, it was demonstrated that burst readout, with multiplexer active only during the readout period, could successfully be implemented at approximately 3.5 K.
Intensity information extraction in Geiger mode detector array based three-dimensional imaging applications
NASA Astrophysics Data System (ADS)
Geiger-mode detectors have single photon sensitivity and picoseconds timing resolution, which make it a good candidate for low light level ranging applications, especially in the case of flash three dimensional imaging applications where the received laser power is extremely limited. Another advantage of Geiger-mode APD is their capability of large output current which can drive CMOS timing circuit directly, which means that larger format focal plane arrays can be easily fabricated using the mature CMOS technology. However Geiger-mode detector based FPAs can only measure the range information of a scene but not the reflectivity. Reflectivity is a major characteristic which can help target classification and identification. According to Poisson statistic nature, detection probability is tightly connected to the incident number of photon. Employing this relation, a signal intensity estimation method based on probability inversion is proposed. Instead of measuring intensity directly, several detections are conducted, then the detection probability is obtained and the intensity is estimated using this method. The relation between the estimator's accuracy, measuring range and number of detections are discussed based on statistical theory. Finally Monte-Carlo simulation is conducted to verify the correctness of this theory. Using 100 times of detection, signal intensity equal to 4.6 photons per detection can be measured using this method. With slight modification of measuring strategy, intensity information can be obtained using current Geiger-mode detector based FPAs, which can enrich the information acquired and broaden the application field of current technology.
Wang, Fei
Determination of selected water-soluble vitamins using hydrophilic chromatography: a comparison of photodiode array, fluorescence, and coulometric detection, and validation in a breakfast cereal matrix.
Water-soluble vitamins are an important class of compounds that require quantification from food sources to monitor nutritional value. In this study we have analysed six water-soluble B vitamins ([thiamine (B1), riboflavin (B2), nicotinic acid (B3, NAc), nicotinamide (B3, NAm), pyridoxal (B6), folic acid (B9)], and ascorbic acid (vit C) with hydrophilic interaction liquid chromatography (HILIC), and compared UV, fluorescent (FLD) and coulometric detection to optimise a method to quantitate the vitamins from food sources. Employing UV/diode array (DAD) and fluorimetric detection, six B vitamins were detected in a single run using gradient elution from 100% to 60% solvent B [10mM ammonium acetate, pH 5.0, in acetonitrile and water 95:5 (v:v)] over 18 min. UV detection was performed at 268 nm for B1, 260 nm for both B3 species and 284 nm for B9. FLD was employed for B2 at excitation wavelength of 268 nm, emission of 513 nm, and 284 nm/317 nm for B6. Coulometric detection can be used to detect B6 and B9, and vit C, and was performed isocratically at 75% and 85% of solvent B, respectively. B6 was analysed at a potential of 720 mV, while B9 was analysed at 600 mV, and vit C at 30 mV. Retention times (0.96 to 11.81 min), intra-day repeatability (CV 1.6 to 3.6), inter-day variability (CV 1.8 to 11.1), and linearity (R 0.9877 to 0.9995) remained good under these conditions with limits of detection varying from 6.6 to 164.6 ng mL(-1), limits of quantification between 16.8 and 548.7 ng mL(-1). The method was successfully applied for quantification of six B vitamins from a fortified food product and is, to our knowledge, the first to simultaneously determine multiple water-soluble vitamins extracted from a food matrix using HILIC. PMID:24792530
Langer, Swen; Lodge, John K
Silicon PIN diode hybrid arrays for charged particle detection: Building blocks for vertex detectors at the SSC
Two-dimensional arrays of solid state detectors have long been used in visible and infrared systems. Hybrid arrays with separately optimized detector and readout substrates have been extensively developed for infrared sensors. The characteristics and use of these infrared readout chips with silicon PIN diode arrays produced by MICRON SEMICONDUCTOR for detecting high-energy particles are reported. Some of these arrays have been produced in formats as large as 512 /times/ 512 pixels; others have been radiation hardened to total dose levels beyond 1 Mrad. Data generation rates of 380 megasamples/second have been achieved. Analog and digital signal transmission and processing techniques have also been developed to accept and reduce these high data rates. 9 refs., 15 figs., 2 tabs.
Kramer, G.; Gaalema, S.; Shapiro, S.L.; Dunwoodie, W.M.; Arens, J.F.; Jernigan, J.G.
SiPM detectors for the ASTRI project in the framework of the Cherenkov Telescope Array
NASA Astrophysics Data System (ADS)
The Cherenkov Telescope Array (CTA) is a worldwide new generation project aimed at realizing an array of a hundred ground based gamma-ray telescopes. ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) is the Italian project whose primary target is the development of an end-to-end prototype, named ASTRI SST-2M, of the CTA small size class of telescopes devoted to investigation of the highest energy region, from 1 to 100 TeV. Next target is the implementation of an ASTRI/CTA mini-array based on seven identical telescopes. Silicon Photo-Multipliers (SiPMs) are the semiconductor photosensor devices designated to constitute the camera detection system at the focal plane of the ASTRI telescopes. SiPM photosensors are suitable for the detection of the Cherenkov flashes, since they are very fast and sensitive to the light in the 300-700nm wavelength spectrum. Their drawbacks compared to the traditional photomultiplier tubes are high dark count rates, after-pulsing and optical cross-talk contributions, and intrinsic gains strongly dependent on temperature. Nonetheless, for a single pixel, the dark count rate is well below the Night Sky Background, the effects of cross-talk and afterpulses are typically lower than 20%, and the gain can be kept stable against temperature variations by means of adequate bias voltage compensation strategies. This work presents and discusses some experimental results from a large set of measurements performed on the SiPM sensors to be used for the ASTRI SST-2M prototype camera and on recently developed detectors demonstrating outstanding performance for the future evolution of the project in the ASTRI/CTA mini-array.
Billotta, Sergio; Marano, Davide; Bonanno, Giovanni; Belluso, Massimiliano; Grillo, Alessandro; Garozzo, Salvatore; Romeo, Giuseppe; Timpanaro, Maria Cristina; Maccarone, Maria Concetta C.; Catalano, Osvaldo; La Rosa, Giovanni; Sottile, Giuseppe; Impiombato, Domenico; Gargano, Carmelo; Giarrusso, Salavtore
Design and initial performance evaluation of a novel PET detector module based on compact SiPM arrays
Silicon Photomultiplier (SiPM) has been demonstrated to be a high performance PET sensor as alternative to conventional photomutiplier tubes. The aim of this work is to develop a PET detector module with compact SiPM device which consists of 3�3 SiPM arrays (4�4 pixels each array,3.17�3.17 mm2 each pixel). A compact design of readout electronics is proposed based on discretized position-sensitive
Tianpeng Xu; Peng Fan; Tianyu Ma; Shi Wang; Zhi Deng; Lingjun Lu; Yaqiang Liu
Thermal and Cold Neutron Computed Tomography at the Los Alamos Neutron Scattering Center Using an Amorphous Silicon Detector Array
The use of the EG and G-Heimann RTM 128 or dpiX FS20 amorphous silicon (a-Si) detector array for thermal neutron radiography\\/computed tomography has proven to be a quick and efficient means of producing high quality digital radiographic images. The resolution, although not as good as film, is about 750 pm with the RTM and 127 pm with the dpiX array
T. N. Claytor; M. J. Schwab; E. H. Farnum; T. E. McDonald; D. A. Summa; M. J. Sheats; D. M. Stupin; W. L. Sievers
Radiation damage of amorphous silicon photodiode sensors
The effect of [sup 60]Co radiation on the leakage current behavior of hydrogenated amorphous silicon photodiode sensors has been investigated. These sensors, with an n-i-p construction, are identical to those used on two-dimensional, pixelated imaging arrays currently under development. Sensor leakage current is reported as a function of dose up to a cumulative dose of [approximately]3 [times] 10[sup 6] cGy. Following the irradiation, the effect of room-temperature annealing on the leakage current was quantitatively studied. Finally, sensor noise measurements prior to and after the irradiation are also reported. The implications of this study for radiotherapy imaging are discussed.
Boundry, J.M.; Antonuk, L.E. (Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Radiation Oncology)
Electronics and data acquisition system of the extensive air shower detector array at the University of Puebla
NASA Astrophysics Data System (ADS)
Field programmable gate arrays (FPGAs) are playing an increasing role in DAQ systems in cosmic ray experiments due to their high speed and integration and their low cost and low power comsumption. In this paper we describe in detail the new electronics and data acquisition system based on FPGA boards of the extensive air shower detector array built in the Campus of the University of Puebla. The purpose of this detector array is to measure the energy and arrival direction of primary cosmic rays with energies around 1015 eV. The array consists of 10 liquid scintillator detectors and 6 water Cherenkov detectors (of 1.86 m2 cross section), distributed in a square grid with a detector spacing of 20 m over an area of 4000 m2. The electronics described also makes use of analog to digital converters with a resolution of 10 bits and sampling speeds of 100 MS/s to digitize the PMT signals. We also discuss the advantages of discriminating the PMT signals inside the FPGAs with respect to the conventional use of dedicated discrimination circuits.
Perez, E.; Salazar, H.; Villasenor, L.; et al.
Initial results from the Sherbrooke avalanche photodiode positron tomograph
The design features and engineering constraints of a PET system based on avalanche photodiode (APD) detectors have been described in a previous report. Here, the authors present the initial results obtained with the Sherbrooke APD-PET scanner, a very high spatial resolution device designed for dynamic imaging of small and medium-sized laboratory animals such as rats, cats, rabbits and small monkeys.
R. Lecomte; J. Cadorette; S. Rodrigue; D. Lapointe; D. Rouleau; M. Bentourkia; R. Yao; P. Msaki
Performance characteristics of the new detector array for the SANS2d instrument on the ISIS spallation neutron source
NASA Astrophysics Data System (ADS)
The performance of the new position sensitive neutron detector arrays of the Small Angle Neutron Scattering (SANS) instrument SANS2d is described. The SANS2d instrument is one of the seven instruments currently available for users on the second target station (TS2) of the ISIS spallation neutron source. Since the instrument became operational in 2009 it has used two one metre square multi-wire proportional detectors (MWPC). However, these detectors suffer from a low count rate capability, are easily damaged by excess beam and are then expensive to repair. The new detector arrays each consist of 120 individual position sensitive detector tubes, filled with 15 bar of 3He. Each of the tubes is one metre long and has a diameter of 8mm giving a detector array with an overall area of one square metre. Two such arrays have been built and installed in the SANS2d vacuum tank where they are currently taking user data. For SANS measurements operation of the detector within a vacuum is essential in order to reduce air scattering. A novel, fully engineered approach has been utilised to ensure that the high voltage connections and preamps are located inside the SANS2d vacuum tank at atmospheric pressure, within air tubes and air boxes respectively. The signal processing electronics and data acquisition system are located remotely in a counting house outside of the blockhouse. This allows easy access for maintenance purposes, without the need to remove the detectors from the vacuum tank. The design will be described in detail. A position resolution of 8mm FWHM or less has been measured along the length of the tubes. The initial measurements taken from a standard sample indicate that whilst the detector arrays themselves only represent a moderate improvement in overall detection efficiency (~ 20%), compared to the previous detector, the count rate capability is increased by a factor of 100. A significant advantage of the new array is the ability to change a single tube in situ within approximately one day with a relatively small staff effort. The results obtained from the first user trials are reported.
Duxbury, D.; Heenan, R.; McPhail, D.; Raspino, D.; Rhodes, N.; Rogers, S.; Schooneveld, E.; Spill, E.; Terry, A.
Tapered LSO Arrays for Small Animal PET
By using detectors with good depth encoding accuracy (~ 2 mm), an animal PET scanner can be built with a small ring diameter and thick crystals to simultaneously obtain high spatial resolution and high sensitivity. However, there will be large wedge-shaped gaps between detector modules in such a scanner if traditional cuboid crystal arrays are used in a polygonal arrangement. The gaps can be minimized by using tapered scintillator arrays enabling the sensitivity of the scanner to be further improved. In this work, tapered lutetium oxyorthosilicate (LSO) arrays with different crystal dimensions and different combinations of inter-crystal reflector and crystal surface treatments were manufactured and their performance was evaluated. Arrays were read out from both ends by position-sensitive avalanche photodiodes (PSAPDs). In the optimal configuration, arrays consisting of 0.5 mm LSO elements could be clearly resolved and a depth of interaction resolution of 2.6 mm was obtained for a 20-mm thick array. For this tapered array, the intrinsic spatial is degraded from 0.67 mm to 0.75 mm compared to a standard cuboidal array with similar dimensions, while the increase in efficiency is 41%. Tapered scintillator arrays offer the prospect of improvements in sensitivity and sampling for small-bore scanners, without large increases in manufacturing complexity. PMID:21119228
Yang, Yongfeng; James, Sara St.; Wu, Yibao; Du, Huini; Qi, Jinyi; Farrell, Richard; Dokhale, Purushottam A.; Shah, Kanai S.; Vaigneur, Keith; Cherry, Simon R.
Nuclear Structure of Radioactive Neutron-Rich Nuclei with 4pi Detector Arrays
In-beam studies of {gamma}-ray spectroscopy of radioactive neutron-rich nuclei using the 4{pi} TIGRESS array at TRIUMF requires a ''tag'' to improve the selectivity of the detected {gamma} rays in the high {gamma}-ray background produced by radioactive beams and the need for Doppler-shift correction. We propose development of two types of large solid angle auxiliary charged particle detectors to be used in conjunction with TRIGRESS in order to provide the required tag. The initial phase of detector development will focus on research involving light-mass radioactive beams with Z {le} 20. Gas avalanche detectors, such as CHICO, are not the ideal detector for lighter ions. Therefore, a new detector system, called Bambino, is being developed that is based on commercially available CD type position-sensitive silicon detectors. Three CD-S2 detectors, with a thickness of 140 {micro}m, have been ordered from Micron Semiconductor Ltd. A split spherical target chamber will be built in Rochester to accommodate two of those CD detectors in both forward and backward directions. These detectors will be placed 3 cm from the target, providing an angular coverage from 20.1{sup o} to 49.4{sup o} for the forward hemisphere and from 130.6{sup o} to 159.9{sup o} for the backward hemisphere. The detectors will us ten 8-channels preamplifiers, from Swan Research, that will be mechanically mounted on both the entrance and exit beam pipes. The work on both the internal and external cables connecting the detectors to the preamplifiers, vacuum feedthrough etc. is in progress. In addition, a vacuum chamber has been ordered from Kurt J. Lesker Company for testing these detectors. Bambino should be ready by the spring 2006. The second phase will involve the development of a next generation CHICO-like gas avalanche detector for experiments involving heavier radioactive beams. CHICO, a highly segmented parallel-plate avalanche counter, has proven to be very successful when used in conjunction with Gammasphere [1-2]. It has an angular coverage of 2.8{pi} sr and an angular resolution of 1{sup o} in {theta} and 4.6{sup o} in {phi} in addition to a time resolution of 500 ps. The proposed new avalanche detector will have an improved position resolution that matches the (2 mm) achieved by TIGRESS. This longer-term detector development project is predicated on future funding and we actively seek collaborators. Such a detector system, used in conjunction with a thin target, allows the detection of both scattered and recoiling nuclei in kinematic coincidence providing a unique tag for the detected {gamma} rays and at the same time providing sufficient information for the proper Doppler-shift corrections. This detector system can accommodate many types of experiments involving (quasi) two-body kinematics, such as Coulomb excitation [2-7], few-nucleon transfer reactions [8-10], deep-inelastic reactions [11-16], and spontaneous fissions [1] or fusion-fission reactions [17-20] we have carried out in the past. The initial phase of proposed experiments will be to study, by Coulomb excitation, the issue of the ''island of inversion'' for the Mg isotopes in the N {approx} 20 region. The B(E2) values for the first 2{sup +} states of {sup 30,32,34}Mg have been measured using intermediate-energy Coulomb excitation at projectile fragmentation facilities. The B(E2) value for {sup 30}Mg also was measured recently via conventional Coulomb excitation at the CERN REX-ISOLDE facility. The spread in measured B(E2)'s of up to a factor of two is insufficient to distinguish among various shell model predictions. Obviously, more precise measurements are necessary to ascertain how well the shell model can predict the properties of neutron-rich nuclei. An accuracy about 5% for the measured B(E2) can be achieved assuming a three-day beam time with an intensity about 3 x 10{sup 4} p/s of {sup 32}Mg on a 3 mg/cm{sup 2} {sup 208}Pb target at E{sub lab} = 115 MeV. A measure of the shape or the static quadrupole moment of this nucleus, in addition to the B(E2) value, would be possible if the
Wu, C Y; Becker, J A; Cline, D
Effects of 1-MeV gamma radiation on a multi-anode microchannel array detector tube
NASA Technical Reports Server (NTRS)
A multianode microchannel array (MAMA) detector tube without a photocathode was exposed to a total dose of 1,000,000 rads of 1-MeV gamma radiation from a Co-60 source. The high-voltage characteristic of the microchannel array plate, average dark count, gain, and resolution of pulse height distribution characteristics showed no degradation after this total dose. In fact, the degassing of the microchannels induced by the high radiation flux had the effect of cleaning up the array plate and improving its characteristics.
Timothy, J. G.; Bybee, R. L.
First results of neutrinoless double beta decay search with the GERmanium Detector Array "GERDA"
NASA Astrophysics Data System (ADS)
The study of neutrinoless double beta decay is the most powerful approach to the fundamental question if the neutrino is a Majorana particle, i.e. its own anti-particle. The observation of the lepton number violating neutrinoless double beta decay would establish the Majorana nature of the neutrino. Until now neutrinoless double beta decay was not observed. The GERmanium Detector Array, GERDA is a double beta decay experiment located at the INFN Gran Sasso National Laboratory, Italy. GERDA operates bare Ge diodes enriched in 76Ge in liquid argon supplemented by a water shield. The exposure accumulated adds up to 21.6 kg� yr with a background level of 1.8 � 10-2 cts/(keV�kg�yr). The results of the Phase I of the experiment are presented and the preparation of the Phase II is briefly discussed.
Janicsk� Cs�thy, J�zsef
Optimizing the signal-to-noise ratio in the measurement of photon pairs with detector arrays
NASA Astrophysics Data System (ADS)
To evidence multimode spatial entanglement of spontaneous down-conversion, detector arrays allow a full-field measurement, without any a priori selection of the paired photons. We show by comparing results of the recent literature that electron-multiplying CCD cameras allow, in the present state of technology, the detection of quantum correlations with the best signal-to-noise ratio (SNR), while intensified CCD cameras allow at best the identification of pairs. The SNR appears to be proportional to the square root of the number of coherence cells in each image, or Schmidt number. Then corrected estimates are derived for extended coherence cells and not-very-low and non-space-stationary photon fluxes. Finally, experimental measurements of the SNR confirm our model.
Lantz, Eric; Moreau, Paul-Antoine; Devaux, Fabrice
Touch-Sensitive Active-Matrix Display with Liquid-Crystal Capacitance Detector Arrays
NASA Astrophysics Data System (ADS)
We present two types of touch in-cell technology for active-matrix liquid crystal displays (AMLCDs) with liquid-crystal capacitance detector arrays embedded in a hydrogenated amorphous silicon (a-Si:H)-based backplane. The scanning method can determine and provide multiple simultaneous touch locations on the basis of the information extracted from each sensing element. On the other hand, the crossing method provides the position information from the coordinate information such that the system complexity and power consumption are expected to be considerably reduced. In both cases, by limiting the operation of sensors to the subthreshold region, we expect that the degradation of a-Si:H thin-film transistors (TFTs) will be suppressed and reliability will be ensured. Their relatively simple architecture enables the proposed touch-panel function to be readily integrated within large-area displays.
Hyun-Sang Park,; Yong-Jin Kim,; Min-Koo Han,
New insights from studies of spontaneous fission with large detector arrays
NASA Astrophysics Data System (ADS)
The new insights into a) the rapidly varying structures of neutron-rich nuclei up to spins as high as 20 + and 19 -, b) the spontaneous fission process itself, and c) modes of cluster radioactivity that have come out of studies of spontaneous fission of 242Pu, 248Cm and 252Cf with large detector arrays are presented. The studies include ?-?-? coincidences with the second generation (14-20 Compton-suppressed Ge arrays) and new, third generation (35-45 Compton-suppressed Ge arrays, Gammasphere and Eurogam) gamma-ray detector arrays. The neutron-rich nuclei observed span the full range from superdeformed ( ?2 ? 0.4) double-magic ground states to spherical double-magic nuclei and competing shapes in between. New structure insights include the following: New regions of identical ground state bands to spins of 10 + to 16 + were discovered; one at the sudden onset of large deformation at N=60,62 in both even- and odd-A 98-101Sr, one at midshell N = 64,66 in 108,110Ru, one for N = 88-90 144,146Ba, one for N = 92-94 152,154Nd, and at high spin in 156Nd and also in excited bands in these regions. New shape coexisting structures in both even- and odd-A for A = 96-102 Sr and Zr nuclei are found. Evidence is found in both even-even and odd-A nuclei for a new region of octupole deformation around Z = 56 and N = 86-88. Rapid changes in moments of inertia are observed with changes in Z and N of two units with sudden changes in the moments of inertia associated with band crossings. The levels in many neutron-rich nuclei are observed for the first time. Earlier, plunger studies yielded lifetimes of low spin states and recently the Doppler Shift Line Shape Analysis yielded lifetimes of high spin states. For the first time, direct measurements of yields and neutron multiplicities have been made for five correlated pairs of fission fragments of Sr?Nd, Zr?Ce, Mo?Ba, Ru?Xe and Pd?Te nuclei. Neutron multiplicities from 0-10 v emission (10v for the first time) were observed in Mo?Ba correlated pairs with the 0 and 7-10 neutron-emission yields enhanced compared to gross yields for all fragments. The Mo?Ba data provide evidence for two different fission modes. By unfolding the observed Mo?Ba yields, the masses and excitation energies and mass distributions at scission were extracted. These data revealed a new mode involving the high neutron multiplicities that occurs essentially through one pair, 108Mo? 144Ba, 107Mo? 145Ba, or 106Mo? 146Ba or some combination where the 144Ba, 145Ba and/or 146Ba at scission are hyperdeformed with a long-to-short axis ratio of 3:1. The zero-neutron emission channels provide new examples of the cold rearrangements of nucleons in a new type of cluster radioactivity. The cluster radioactivity model predicted the observed enhancements of the zero-neutron channels for odd-A-odd-A nuclei as well as the observed fine structure, that is, the spin distributions of the two fragments. The measurements of intensities and ?-?-? coincidences in SF with large detector arrays open a new era in the determination of previously inaccessible properties of neutron-rich nuclei and the fission process.
Hamilton, J. H.; Ramayya, A. V.; Zhu, S. J.; Ter-Akopian, G. M.; Oganessian, Yu. Ts.; Cole, J. D.; Rasmussen, J. O.; Stoyer, M. A.
Status of the Germanium Detector Array (GERDA) in the search of neutrinoless ?? decays of 76Ge at LNGS
NASA Astrophysics Data System (ADS)
The Germanium Detector Array (GERDA) in the search for neutrinoless ?? decays of 76Ge at LNGS will operate bare germanium diodes enriched in 76Ge in an (optional active) cryogenic fluid shield to investigate neutrinoless ?? decay with a sensitivity of T 1/2 > 2 � 1026 yr after an exposure of 100 kg yr. Recent progress includes the installation of the first underground infrastructures at Gran Sasso, the completion of the enrichment of 37.5 kg of germanium material for detector construction, prototyping of low-mass detector support and contacts, and front-end and DAQ electronics, as well as the preparation for construction of the cryogenic vessel and water tank.
Sch�nert, S.; Abt, I.; Altmann, M.; Bakalyarov, A. M.; Barabanov, I.; Bauer, C.; Bauer, M.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Bettini, A.; Bezrukov, L.; Brudanin, V.; Bolotsky, V. P.; Caldwell, A.; Cattadori, C.; Chirchenko, M. V.; Chkvorets, O.; Demidova, E.; di Vacri, A.; Eberth, J.; Egorov, V.; Farnea, E.; Gangapshev, A.; Gasparro, J.; Grabmayr, P.; Grigoriev, G. Y.; Gurentsov, V.; Gusev, K.; Hampel, W.; Heusser, G.; Heisel, M.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Jochum, J.; Junker, M.; Katulina, S.; Kiko, J.; Kirpichnikov, I. V.; Klimenko, A.; Knapp, M.; Kn�pfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kr�ninger, K.; Kuzminov, V. V.; Laubenstein, M.; Lebedev, V. I.; Liu, X.; Majorovits, B.; Marissens, G.; Nemchenok, I.; Pandola, L.; Peiffer, P.; Pullia, A.; Alvarez, C. R.; Sandukovsky, V.; Scholl, S.; Schreiner, J.; Schwan, U.; Schwingenheuer, B.; Simgen, H.; Smolnikov, A.; Stelzer, F.; Tikhomirov, A. V.; Tomei, C.; Ur, C. A.; Vasenko, A. A.; Vasiliev, S.; Wei�haar, D.; Wojcik, M.; Yanovich, E.; Yurkowski, J.; Zhukov, S. V.; Zocca, F.; Zuzel, G.
Reducing the Read Noise of H2RG Detector Arrays by more Efficient use of Reference Signals
NASA Technical Reports Server (NTRS)
We present a process for characterizing the correlation properties of the noise in large two-dimensional detector arrays, and describe an efficient process for its removal. In the case of the 2k x 2k HAWAII-2RG detectors (H2RG) detectors from Teledyne which are being used on the Near Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope (JWST), we find that we can reduce the read noise by thirty percent. Noise on large spatial scales is dramatically reduced. With this relatively simple process, we provide a performance improvement that is equivalent to a significant increase in telescope collecting area for high resolution spectroscopy with NIRSpec.
Rauscher, Bernard J.; Arendt, Richard G.; Fixen, D. J.; Lindler, Don; Loose, Markus; Moseley, S. H.; Wilson, D. V.
Hybrid AlGaN-SiC Avalanche Photodiode for Deep-UV Photon Detection
NASA Technical Reports Server (NTRS)
The proposed device is capable of counting ultraviolet (UV) photons, is compatible for inclusion into space instruments, and has applications as deep- UV detectors for calibration systems, curing systems, and crack detection. The device is based on a Separate Absorption and Charge Multiplication (SACM) structure. It is based on aluminum gallium nitride (AlGaN) absorber on a silicon carbide APD (avalanche photodiode). The AlGaN layer absorbs incident UV photons and injects photogenerated carriers into an underlying SiC APD that is operated in Geiger mode and provides current multiplication via avalanche breakdown. The solid-state detector is capable of sensing 100-to-365-nanometer wavelength radiation at a flux level as low as 6 photons/pixel/s. Advantages include, visible-light blindness, operation in harsh environments (e.g., high temperatures), deep-UV detection response, high gain, and Geiger mode operation at low voltage. Furthermore, the device can also be designed in array formats, e.g., linear arrays or 2D arrays (micropixels inside a superpixel).
Aslam, Shahid; Herrero, Federico A.; Sigwarth, John; Goldsman, Neil; Akturk, Akin
Final report on LDRD project : single-photon-sensitive imaging detector arrays at 1600 nm.
The key need that this project has addressed is a short-wave infrared light detector for ranging (LIDAR) imaging at temperatures greater than 100K, as desired by nonproliferation and work for other customers. Several novel device structures to improve avalanche photodiodes (APDs) were fabricated to achieve the desired APD performance. A primary challenge to achieving high sensitivity APDs at 1550 nm is that the small band-gap materials (e.g., InGaAs or Ge) necessary to detect low-energy photons exhibit higher dark counts and higher multiplication noise compared to materials like silicon. To overcome these historical problems APDs were designed and fabricated using separate absorption and multiplication (SAM) regions. The absorption regions used (InGaAs or Ge) to leverage these materials 1550 nm sensitivity. Geiger mode detection was chosen to circumvent gain noise issues in the III-V and Ge multiplication regions, while a novel Ge/Si device was built to examine the utility of transferring photoelectrons in a silicon multiplication region. Silicon is known to have very good analog and GM multiplication properties. The proposed devices represented a high-risk for high-reward approach. Therefore one primary goal of this work was to experimentally resolve uncertainty about the novel APD structures. This work specifically examined three different designs. An InGaAs/InAlAs Geiger mode (GM) structure was proposed for the superior multiplication properties of the InAlAs. The hypothesis to be tested in this structure was whether InAlAs really presented an advantage in GM. A Ge/Si SAM was proposed representing the best possible multiplication material (i.e., silicon), however, significant uncertainty existed about both the Ge material quality and the ability to transfer photoelectrons across the Ge/Si interface. Finally a third pure germanium GM structure was proposed because bulk germanium has been reported to have better dark count properties. However, significant uncertainty existed about the quantum efficiency at 1550 nm the necessary operating temperature. This project has resulted in several conclusions after fabrication and measurement of the proposed structures. We have successfully demonstrated the Ge/Si proof-of-concept in producing high analog gain in a silicon region while absorbing in a Ge region. This has included significant Ge processing infrastructure development at Sandia. However, sensitivity is limited at low temperatures due to high dark currents that we ascribe to tunneling. This leaves remaining uncertainty about whether this structure can achieve the desired performance with further development. GM detection in InGaAs/InAlAs, Ge/Si, Si and pure Ge devices fabricated at Sandia was shown to overcome gain noise challenges, which represents critical learning that will enable Sandia to respond to future single photon detection needs. However, challenges to the operation of these devices in GM remain. The InAlAs multiplication region was not found to be significantly superior to current InP regions for GM, however, improved multiplication region design of InGaAs/InP APDs has been highlighted. For Ge GM detectors it still remains unclear whether an optimal trade-off of parameters can achieve the necessary sensitivity at 1550 nm. To further examine these remaining questions, as well as other application spaces for these technologies, funding for an Intelligence Community post-doc was awarded this year.
Childs, Kenton David; Serkland, Darwin Keith; Geib, Kent Martin; Hawkins, Samuel D.; Carroll, Malcolm S.; Klem, John Frederick; Sheng, Josephine Juin-Jye; Patel, Rupal K.; Bolles, Desta; Bauer, Tom M.; Koudelka, Robert
Detection of ultra-high energy neutrino interactions in ice: comparing radio detector array designs
NASA Astrophysics Data System (ADS)
Ultra-high energy (UHE, >10^18 eV) cosmic neutrinos are anticipated to reveal the most distant, most obscured, and highest energy particle accelerators in the Universe. An almost guaranteed flux of UHE neutrinos is predicted from the interactions of UHE cosmic rays with the cosmic microwave background, and additional contributions may arise from prompt emission at individual sources. The spectrum of UHE neutrinos is a sensitive discriminator of the cosmological evolution of UHE sources, as well as the composition of UHE cosmic rays. At the same time, UHE neutrinos will enable several tests of fundamental physics, including constraints on the neutrino-nucleon interaction cross section at center-of-momentum energies ~100 TeV, and searches for Lorentz invariance violation.Theoretical predictions and subsequent laboratory measurements of coherent radio emission from showers initiated by neutrino interactions in dielectric media (e.g., ice, sand, salt, lunar regolith) have motivated diverse experimental approaches involving "detectors" comprised of up to millions of cubic kilometers of natural materials. I will discuss simulation results comparing the expected performance of several proposed radio detector array designs with subterranean, ice shelf, and above ice configurations.
Bechtol, Keith; Vieregg, Abigail
LWIR heterodyne HgCdTe detectors
NASA Astrophysics Data System (ADS)
Single element and linear array photodetectors operating in heterodyne mode for CO2 laser radiation detection have been developed and investigated. P-type mercury cadmium telluride (MCT) crystal with x=0.21 composition and hole concentration 1x1016 cm-3 at T=77K were used as substrates. The p-n junctions in p-type MCT were formed by ion implantation. Detector was packaged in metal-glass dewar together with preamplifier. Cooling was performed by liquid nitrogen. Single-element heterodyne detector with p- n junction area 300X300 micrometers operates at frequencies up to 100 MHz. The noise equivalent power (NEP) at 10,6 micrometers wavelength is equal to 5x1020 W/Hz for an applied local oscillator power 0,5 mW. 10-element photodiode linear array heterodyne detector been developed and investigated.
Boltar, K. O.; Bourlakov, I. D.; Golovin, S. V.; Lognikov, V. E.; Mansvetov, N. G.
Analysis of genetically modified organisms by pyrosequencing on a portable photodiode-based bioluminescence sequencer.
A portable bioluminescence analyser for detecting the DNA sequence of genetically modified organisms (GMOs) was developed by using a photodiode (PD) array. Pyrosequencing on eight genes (zSSIIb, Bt11 and Bt176 gene of genetically modified maize; Lectin, 35S-CTP4, CP4EPSPS, CaMV35S promoter and NOS terminator of the genetically modified Roundup ready soya) was successfully detected with this instrument. The corresponding limit of detection (LOD) was 0.01% with 35 PCR cycles. The maize and soya available from three different provenances in China were detected. The results indicate that pyrosequencing using the small size of the detector is a simple, inexpensive, and reliable way in a farm/field test of GMO analysis. PMID:24518318
Song, Qinxin; Wei, Guijiang; Zhou, Guohua
Large dynamic range radiation detector and methods thereof
According to one embodiment, a radiation detector comprises a scintillator and a photodiode optically coupled to the scintillator. The radiation detector also includes a bias voltage source electrically coupled to the photodiode, a first detector operatively electrically coupled to the photodiode for generating a signal indicative of a level of a charge at an output of the photodiode, and a second detector operatively electrically coupled to the bias voltage source for generating a signal indicative of an amount of current flowing through the photodiode.
Marrs, Roscoe E. (Livermore, CA); Madden, Norman W. (Sparks, NV)
Photon-counting array detectors for space and ground-based studies at ultraviolet and vacuum ultraviolet /VUV/ wavelengths
NASA Technical Reports Server (NTRS)
The Multi-Anode Microchannel Arrays (MAMAs) are a family of photoelectric photon-counting array detectors, with formats as large as (256 x 1024)-pixels that can be operated in a windowless configuration at vacuum ultraviolet (VUV) and soft X-ray wavelengths or in a sealed configuration at ultraviolet and visible wavelengths. This paper describes the construction and modes of operation of (1 x 1024)-pixel and (24 x 1024)-pixel MAMA detector systems that are being built and qualified for use in sounding-rocket spectrometers for solar and stellar observations at wavelengths below 1300 A. The performance characteristics of the MAMA detectors at ultraviolet and VUV wavelengths are also described.
Timothy, J. G.; Bybee, R. L.
Thermal and Cold Neutron Computed Tomography at the Los Alamos Neutron Scattering Center Using an Amorphous Silicon Detector Array
The use of the EG and G-Heimann RTM 128 or dpiX FS20 amorphous silicon (a-Si) detector array for thermal neutron radiography/computed tomography has proven to be a quick and efficient means of producing high quality digital radiographic images. The resolution, although not as good as film, is about 750 pm with the RTM and 127 pm with the dpiX array with a dynamic range in excess of 2,800. In many respects using an amorphous silicon detector is an improvement over other techniques such as imaging with a CCD camera, using a storage phosphor plate or film radiography. Unlike a CCD camera, which is highly susceptible to radiation damage, a-Si detectors can be placed in the beam directly behind the object under examination and do not require any special optics or turning mirrors. The amorphous silicon detector also allows enough data to be acquired to construct a digital image in just a few seconds (minimum gate time 40 ms) whereas film or storage plate exposures can take many minutes and then need to be digitized with a scanner. The flat panel can therefore acquire a complete 3D computed tomography data set in just a few tens of minutes. While a-Si detectors have been proposed for use in imaging neutron beams, this is the first reported implementation of such a detector for neutron imaging.
Claytor, T.N.; Schwab, M.J.; Farnum, E.H.; McDonald, T.E.; Summa, D.A.; Sheats, M.J.; Stupin, D.M.; Sievers, W.L.
Characterization of direct readout Si:Sb and Si:Ga infrared detector arrays for space-based astronomy
NASA Technical Reports Server (NTRS)
Preliminary test results from the evaluation of Si:Sb and Si:Ga 58 x 62-element infrared detector arrays are presented. These devices are being characterized under background conditions and readout rates representative of operation in orbiting, crogenically-cooled infrared observatories. The arrays are hybridized to silicon direct-readout multiplexers which allow random-access and nondestructive readout. Array performance optimization is being conducted with a flexible microcomputer-based drive and readoaut electronics system. Preliminary Si:Sb measurements indicate a sense node capacitance of 0.06 pF, peak (28-micron) responsivity above 3 A/W at 2V bias, read noise of 130 rms e(-), dark current approximately 10 e(-)/s, and a well capacity greater than 10 to the 5th e(-). The limited test data available on the performance of the Si:Ga array are also discussed.
Mckelvey, Mark E.; Mccreight, Craig R.; Goebel, John H.; Moss, Nicolas N.; Savage, Maureen L.
The VCSEL-based array optical transmitter (ATx) development towards 120-Gbps link for collider detector: development update
NASA Astrophysics Data System (ADS)
A compact radiation-tolerant array optical transmitter module (ATx) is developed to provide data transmission up to 10Gbps per channel with 12 parallel channels for collider detector applications. The ATx integrates a Vertical Cavity Surface-Emitting Laser (VCSEL) array and driver circuitry for electrical to optical conversion, an edge warp substrate for the electrical interface and a micro-lens array for the optical interface. This paper reports the continuing development of the ATx custom package. A simple, high-accuracy and reliable active-alignment method for the optical coupling is introduced. The radiation-resistance of the optoelectronic components is evaluated and the inclusion of a custom-designed array driver is discussed.
Guo, D.; Liu, C.; Chen, J.; Chramowicz, J.; Gong, D.; Hou, S.; Huang, D.; Jin, G.; Li, X.; Liu, T.; Prosser, A.; Teng, P. K.; Ye, J.; Zhou, Y.; You, Y.; Xiang, A. C.; Liang, H.
Boron-layer silicon photodiodes for high-efficiency low-energy electron detection Agata Sakic a,
for use as low-energy electron detectors have been fabricated using a pure-boron technology to form the pBoron-layer silicon photodiodes for high-efficiency low-energy electron detection Agata Sakic´ a photodiodes Electron detection Low-energy electrons Boron deposition Ultrashallow junctions Responsivity
Technische Universiteit Delft
Uncooled infrared detector with 12?m pixel pitch video graphics array
NASA Astrophysics Data System (ADS)
Uncooled infrared detectors with 12?m pixel pitch video graphics array (VGA) have been developed. To improve the signal to noise ratio (SNR) for 12?m pixel pitch, a highly sensitive bolometer material, an advanced pixel structure for thermal isolation and a newly designed read-out IC (ROIC) have been also developed. The bolometer material has been improved by using vanadium niobate. Over a wide range of temperature, temperature coefficient of resistance (TCR) is achieved higher level than -3.6%/K, which is 2 times higher than that for the conventional bolometer material. For thermal isolation, thermal conductance (Gth) value for the new pixel structure, fabricated by using triple level sacrificial layer process, is estimated to be 5nW/K, which is 1/5 times lower than that for the conventional pixel structure. On the other hand, since the imaging area is reduced by the pixel pitch, the uniformity of pixel can be improved. This enables to remove the non-uniformity correction (NUC) circuit in the ROIC. Removal of this circuit is effective for low power and low noise. This 12?m pixel pitch VGA detector is packaged in a compact (24 � 24 � 6.5 mm) and lightweight (11g) ceramic package. In addition, it has been incorporated in a newly developed prototype miniature imager. The miniature imager has dimension of 25(H) �25(W) �28(L) mm and weight of 30g. This imager is compact and small enough to fit in your hand. Hereafter, this imager is greatly expected to be applied to mobile systems.
Endoh, Tsutomu; Tohyama, Shigeru; Yamazaki, Takao; Tanaka, Yutaka; Okuyama, Kuniyuki; Kurashina, Seiji; Miyoshi, Masaru; Katoh, Kouji; Yamamoto, Takashi; Okuda, Yuuhi; Sasaki, Tokuhito; Ishizaki, Haruo; Nakajima, Tomohiko; Shinoda, Kentaro; Tsuchiya, Tetsuo
Signal and Noise Properties of Position-Sensitive Avalanche Photodiodes
After many years of development, position-sensitive avalanche photodiodes (PSAPDs) are now being incorporated into a range of scintillation detector systems, including those used in high-resolution small-animal PET and PET/MR scanners. In this work, the signal, noise, signal-to-noise ratio (SNR), flood histogram and timing resolution were measured for lutetium oxyorthosilicate (LSO) scintillator arrays coupled to PSAPDs ranging in size from 10�20 mm, and the optimum bias voltage and working temperature determined. Variations in the SNR performance of PSAPDs with the same dimensions were small, but the SNR decreased significantly with increasing PSAPD size and increasing temperature. Smaller PSAPDs (10 mm and 15 mm in width) produced acceptable flood histograms at 24 �C, and cooling lower than 16 �C produced little improvement. The optimum bias voltage was about 25 V below the break down voltage. The larger 20 mm PSAPDs have lower SNR and require cooling to 0�7 �C for acceptable performance. The optimum bias voltage also is lower (35 V or more below the break down voltage depending on the temperature). Significant changes in the timing resolution were observed as the bias voltage and temperature were varied. Higher bias voltages provided better timing resolution. The best timing resolution obtained for individual crystals was 2.8 ns and 3.3 ns for the 10 mm and 15 mm PSAPDs, respectively. The results of this work provide useful guidance for selecting the bias voltage and working temperature for scintillation detectors that incorporate PSAPDs as the photodetector. PMID:21896961
Yang, Yongfeng; Wu, Yibao; Farrell, Richard; Dokhale, Purushottam A.; Shah, Kanai S.; Cherry, Simon R.
Breadboard linear array scan imager using LSI solid-state technology
NASA Technical Reports Server (NTRS)
The performance of large scale integration photodiode arrays in a linear array scan (pushbroom) breadboard was evaluated for application to multispectral remote sensing of the earth's resources. The technical approach, implementation, and test results of the program are described. Several self scanned linear array visible photodetector focal plane arrays were fabricated and evaluated in an optical bench configuration. A 1728-detector array operating in four bands (0.5 - 1.1 micrometer) was evaluated for noise, spectral response, dynamic range, crosstalk, MTF, noise equivalent irradiance, linearity, and image quality. Other results include image artifact data, temporal characteristics, radiometric accuracy, calibration experience, chip alignment, and array fabrication experience. Special studies and experimentation were included in long array fabrication and real-time image processing for low-cost ground stations, including the use of computer image processing. High quality images were produced and all objectives of the program were attained.
Tracy, R. A.; Brennan, J. A.; Frankel, D. G.; Noll, R. E.
A Silicon-Based Positive-Intrinsic-Negative Photodetector Double Linear Array on a Thick Intrinsic Epitaxial Layer
NASA Astrophysics Data System (ADS)
To measure small particles in clouds without the optical amplification system, a new type of p�i�n photodetector linear array with 128 diode units altogether is designed and realized. In each die, there are two rows of photodiode line array, and each row has 64 photodiodes. Every photodiode has a size of 100 ?m � 100 ?m with an individual output, and each of them is isolated by the trenches. The depth of them has the same thickness as that of the epitaxial layer, which is designed to be 30 ?m to guarantee sufficient absorption of photons and leave a margin for the diffusion of p-type and n-type region. The detector has been tested with a laser whose wavelength was 650nm and irradiance is 50mW/cm2. The achieved photocurrent is 2 ?A. Hence, the current responsivity is about 0.4 A/W, and the external quantum efficiency is 76.45%. The dark current is less than 600 pA. Both of the sufficient absorption of photons and low dark current are achieved by utilizing the thick epitaxial intrinsic layer. Low interference of adjacent photodiodes is also guaranteed by the trenches around the photodiodes. With the obtained performance, the photodetector can be used to measure the diameter of precipitation particles in clouds. Therefore, rainfall can be judged based on the diameter of particles.
Yuan, Li; Wu, Can; Zhang, Zhao-Hua; Ren, Tian-Ling
Characterization of carotenes in a combination of a C18 HPLC column with isocratic elution and absorption spectra with a photodiode-array detector
Carotenes have attracted much attention in recent years for their biological function in processes such as photosynthesis.\\u000a The characterization of carotenes is difficult, however, because they consist of only carbon and hydrogen atoms, without oxygen.\\u000a In the present study, we systematically examined the chemical structures of more than 30 carotenes, including most of the\\u000a carotenes found in phototrophic organisms, and
Shinichi Takaichi
Update on the Fabrication and Performance of 2-D Arrays of Superconducting Magnesium Diboride (MgB2) Thermal Detectors for Outer-Planets Exploration
NASA Technical Reports Server (NTRS)
Detectors with better performance than the current thermopile detectors that operate at room temperature will be needed at the focal plane of far-infrared instruments on future planetary exploration missions. We will present an update on recent results from the 2-D array of MgB2 thermal detectors being currently developed at NASA Goddard. Noise and sensitivity results will be presented and compared to thermal detectors currently in use on planetary missions.
Lakew, Brook; Aslam, S.
Design and study of a coplanar grid array CdZnTe detector for improved spatial resolution.
Coplanar grid (CPG) CdZnTe detectors have been used as gamma-ray spectrometers for years. Comparing with pixelated CdZnTe detectors, CPG CdZnTe detectors have either no or poor spatial resolution, which directly limits its use in imaging applications. To address the issue, a 2�2 CPG array CdZnTe detector with dimensions of 7�7�5mm(3) was fabricated. Each of the CPG pairs in the detector was moderately shrunk in size and precisely designed to improve the spatial resolution while maintaining good energy resolution, considering the charge loss at the surface between the strips of each CPG pairs. Preliminary measurements were demonstrated at an energy resolution of 2.7-3.9% for the four CPG pairs using 662keV gamma rays and with a spatial resolution of 3.3mm, which is the best spatial resolution ever achieved for CPG CdZnTe detectors. The results reveal that the CPG CdZnTe detector can also be applied to imaging applications at a substantially higher spatial resolution. PMID:25305523
Ma, Yuedong; Xiao, Shali; Yang, Guoqiang; Zhang, Liuqiang
Evolution of miniature detectors and focal plane arrays for infrared sensors
NASA Technical Reports Server (NTRS)
Sensors that are sensitive in the infrared spectral region have been under continuous development since the WW2 era. A quest for the military advantage of 'seeing in the dark' has pushed thermal imaging technology toward high spatial and temporal resolution for night vision equipment, fire control, search track, and seeker 'homing' guidance sensing devices. Similarly, scientific applications have pushed spectral resolution for chemical analysis, remote sensing of earth resources, and astronomical exploration applications. As a result of these developments, focal plane arrays (FPA) are now available with sufficient sensitivity for both high spatial and narrow bandwidth spectral resolution imaging over large fields of view. Such devices combined with emerging opto-electronic developments in integrated FPA data processing techniques can yield miniature sensors capable of imaging reflected sunlight in the near IR and emitted thermal energy in the Mid-wave (MWIR) and longwave (LWIR) IR spectral regions. Robotic space sensors equipped with advanced versions of these FPA's will provide high resolution 'pictures' of their surroundings, perform remote analysis of solid, liquid, and gas matter, or selectively look for 'signatures' of specific objects. Evolutionary trends and projections of future low power micro detector FPA developments for day/night operation or use in adverse viewing conditions are presented in the following test.
Watts, Louis A.
Performance of BF focal plane array 320x256 InSb detectors
NASA Astrophysics Data System (ADS)
SCD Focal Plane Arrays (FPAs) are based on 320�256 InSb elements, or 640�512 InSb elements. In this paper we introduce the outstanding FPA based on the signal processor 'blue fairy' (BF) that has been designed at SCD, and is now in standard production for the 320�256 InSb FPAs. The BF Focal Plane Processor (FPP) enables integration capacity of more than 15Me- at Integrate While Read (IWR) mode, and more than 30 Me- at Integrate Than Read (ITR) mode. A combined mode for large dynamic range with high sensitivity is possible. An excellent linearity and residual non-uniformity is achieved, starting from extremely low electron capacity up to 13Me- at IWR mode and 24Me- at ITR mode. Many other modes can be selected via a communication channel such as: ITR/IWR, one of seven different gains, one of seven different biases for the detector, windows size and window location. A Correlated Double Sampling (CDS) between frames and rows can be used for low frequency noise reduction, and/or any external electronic gain and offset drift corrections. All these features enable the integration of the BF FPA in large variety application, with high performance at each application.
Nesher, Orna; Elkind, Shimon; Adin, Amnon; Palty, U.; Pelleg, Oshri; Jacobsohn, Eli; Markovitz, T.; Szafranek, Igor; Calahora, Zipora; Oiknine Schlesinger, J.
Shear Force at the Cell-Matrix Interface: Enhanced Analysis for Microfabricated Post Array Detectors
The interplay of mechanical forces between the extracellular environment and the cytoskeleton drives development, repair, and senescence in many tissues. Quantitative definition of these forces is a vital step in understanding cellular mechanosensing. Microfabricated post array detectors (mPADs) provide direct measurements of cell-generated forces during cell adhesion to extracellular matrix. A new approach to mPAD post labeling, volumetric imaging, and an analysis of post bending mechanics determined that cells apply shear forces and not point moments at the matrix interface. In addition, these forces could be accurately resolved from post deflections by using images of post tops and bases. Image analysis tools were then developed to increase the precision and throughput of post centroid location. These studies resulted in an improved method of force measurement with broad applicability and concise execution using a fully automated force analysis system. The new method measures cell-generated forces with less than 5%error and less than 90 seconds of computational time. Using this approach, we demonstrated direct and distinct relationships between cellular traction force and spread cell surface area for fibroblasts, endothelial cells, epithelial cells and smooth muscle cells. PMID:16708468
Lemmon, Christopher A.; Sniadecki, Nathan J.; Ruiz, Sami Alom; Tan, John L.; Romer, Lewis H.; Chen, Christopher S.