text:
Experimental Study of Hypernuclei Electroproduction by High Precision Spectroscopy
Jlab experiment E01-011, carried out in 2005 in JLab Hall C, is the second generation of the hypernuclear spectroscopy experiments by the (e,e{prime}K{sup +}) reaction. The (e,e{prime}K{sup +}) reaction is complimentary to the associated production reactions (K{sup -},{pi}{sup -}), ({pi}{sup +},K{sup +}) since, due to a larger momentum transfer to a hyperon, excitations of both spin-non-flip and spin-flip states are possible. The experiment uses high quality and continuous primary electron beam to produce neutron rich hypernuclei on various targets by the electroproduction. The experimental setup consists of splitter magnet, high resolution kaon spectrometer (HKS) and electron spectrometer (Enge) implemented in new configuration, the so called 'Tilt Method'. Production data was taken on multiple targets: CH{sub 2}, {sup 6}Li, {sup 7}Li, {sup 9}Be, {sup 10}B, {sup 12}C and {sup 28}Si. In present study the analysis of CH{sub 2}, {sup 12}C and {sup 28}Si is presented. The elementary processes of p(e,e{prime}K{sup +}){Lambda}/{Sigma} from CH{sup 2} data were used for calibration of the spectrometer optics and kinematics. The hypernuclear spectra of {sup 12}{sub {Lambda}}B was obtained with ground state resolution of 0.47 {+-} 0.07 MeV (FWHM), the best ever achieved. Feasibility of the electroproduction reaction to study medium to heavy targets has been proven with the first high resolution beyond p-shell hypernuclear spectra from {sup 28}{sub {Lambda}}Al hypernuclei. The obtained results of the E01-011 experiment confirmed that hypernuclear spectroscopy by the (e,e{prime}K{sup +}) reaction is a very useful technique.
Tomislav Seva
ERIC Educational Resources Information Center
THIS DOCUMENT IS AN EXPERIMENTAL VERSION OF A PROGRAMED TEXT ON MEASUREMENT AND PRECISION. PART I CONTAINS 24 FRAMES DEALING WITH PRECISION AND SIGNIFICANT FIGURES ENCOUNTERED IN VARIOUS MATHEMATICAL COMPUTATIONS AND MEASUREMENTS. PART II BEGINS WITH A BRIEF SECTION ON EXPERIMENTAL DATA, COVERING SUCH POINTS AS (1) ESTABLISHING THE ZERO POINT, (2)ģ
Harvard Univ., Cambridge, MA. Harvard Project Physics.
Highly precise experimental device for determining the heat capacity of liquids under pressure
NASA Astrophysics Data System (ADS)
An experimental device for making isobaric heat capacity measurements of liquids under pressure is presented. The device is an adaptation of the Setaram micro-DSC II atmospheric-pressure microcalorimeter, including modifications of vessels and a pressure line allowing the pressure in the measurement system to be set, controlled, and stabilized. The high sensitivity of the apparatus combined with a suitable calibration procedure allows very accurate heat capacity measurements under pressure to be made. The relative uncertainty in the isobaric molar heat capacity measurements provided by the new device is estimated to be 0.08% at atmospheric pressure and 0.2% at higher levels. The device was validated from isobaric molar heat capacity measurements for hexane, nonane, decane, undecane, dodecane, and tridecane, all of which were highly consistent with reported data. It also possesses a high sensitivity as reflected in its response to changes in excess isobaric molar heat capacity with pressure, which were examined in this work for the first time by making heat capacity measurements throughout the composition range of the 1-hexanol+n-hexane system. Finally, preliminary measurements at several pressures near the critical conditions for the nitromethane+2-butanol binary system were made that testify to the usefulness of the proposed device for studying critical phenomena in liquids under pressure.
Gonzßlez-Salgado, D.; Valencia, J. L.; Troncoso, J.; Carballo, E.; Peleteiro, J.; RomanĒ, L.; BessiĶres, D.
Highly precise experimental device for determining the heat capacity of liquids under pressure
An experimental device for making isobaric heat capacity measurements of liquids under pressure is presented. The device is an adaptation of the Setaram micro-DSC II atmospheric-pressure microcalorimeter, including modifications of vessels and a pressure line allowing the pressure in the measurement system to be set, controlled, and stabilized. The high sensitivity of the apparatus combined with a suitable calibration procedure allows very accurate heat capacity measurements under pressure to be made. The relative uncertainty in the isobaric molar heat capacity measurements provided by the new device is estimated to be 0.08% at atmospheric pressure and 0.2% at higher levels. The device was validated from isobaric molar heat capacity measurements for hexane, nonane, decane, undecane, dodecane, and tridecane, all of which were highly consistent with reported data. It also possesses a high sensitivity as reflected in its response to changes in excess isobaric molar heat capacity with pressure, which were examined in this work for the first time by making heat capacity measurements throughout the composition range of the 1-hexanol+n-hexane system. Finally, preliminary measurements at several pressures near the critical conditions for the nitromethane+2-butanol binary system were made that testify to the usefulness of the proposed device for studying critical phenomena in liquids under pressure.
Gonzalez-Salgado, D.; Valencia, J. L.; Troncoso, J.; Carballo, E.; Peleteiro, J.; Romani, L.; Bessieres, D. [Departamento de Fisica Aplicada, Facultad de Ciencias de Ourense, As Lagoas s/n, 32004 Ourense (Spain); Laboratoire de Fluides Complexes, Groupe Haute Pression, Universite de Pau et des Pays de l'Adour, BP 1155, 64013 Pau (France)
High Precision GPS Measurements.
National Technical Information Service (NTIS)
The objective of this project is to develop high precision GPS receivers by utilizing modernized GPS signals at L1, L2, and L5 frequencies to mitigate GPS measurement errors. For each successfully acquired and tracked GPS signal, a GPS receiver generates ...
F. Van Graas Y. Morton
EDITORIAL: High precision atomic physics High precision atomic physics
NASA Astrophysics Data System (ADS)
Accurate atomic collision and structure data are an essential ingredient for a wide range of research fields as well as for major technological applications. Areas from laboratory physics to quantum processing, from plasma research applications in nuclear fusion to lighting research, as well as astrophysics and cosmology, depend critically on such data. But many data still exhibit inconsistencies and inaccuracies, so that significant efforts are continuing to improve the data quality. Additionally, a substantial body of much-needed data is absent from the published literature and from databases. Appreciable progress is being made, aided by greatly improved, or even entirely new, laboratory equipment and by vastly expanded computer power, which has made possible the development of greatly refined atomic structure codes. Thus in recent years, atomic data have not only become more accurate, but the body of data has also greatly increased, highly ionized species and complex heavy atoms have been addressed, fully relativistic treatments have been developed, and new energy and frequency ranges have been explored. This special issue focuses on many of these new sophisticated theoretical and experimental approaches that have made high precision atomic physics a reality. On the experimental side, several contributions cover the area of highly charged ions, where accurate measurements have become possible mainly due to the availability of electron beam ion traps (EBITs) and the utilization of storage rings. Studies of QED effects in Li-like ions, determinations of atomic lifetimes and precision wavelength measurements of highly charged ions are discussed. Furthermore, two contributions illustrate the extremely high precision of spectroscopic measurements for heavy ions and atoms, and two fundamental investigations address a new search for the electric dipole moment of the electron and measurements of the anapole moment in Fr and Rb. On the theoretical side, the contributions demonstrate that new, expanded and refined atomic structure and electron-impact collision codes are successfully applied to complex atomic systems, such as highly charged ions and heavy atoms, using increasingly full relativistic treatments.
Hibbert, Alan; Johnson, Walter; Wiese, Wolfgang
A high precision Penning trap mass spectrometer
Penning ion traps are used as mass spectrometers for high precision determination of mass doublets. We present our experimental setup and discuss in detail possible sources of systematic uncertainties from electric and magnetic field distortions, misalignments and ion-ion interaction. Methods are discussed to deal with the associated line shifts. As a result, we demonstrate experimentally obtained resolutions of a few
Ch. Gerz; D. Wilsdorf; G. Werth
Experimental investigation on focusing characteristics of a He-Ne laser using circular Fresnel zone plate for high-precision alignment of linear accelerators
NASA Astrophysics Data System (ADS)
We experimentally investigate the focusing characteristics of a He-Ne laser at the focal region for the high-precision alignment of long-distance linear accelerators using a circular Fresnel zone plate. The laser wave passing through the Fresnel zone plate having a focal length of 66.7 m propagates for a 268-m-long distance at atmospheric pressure. A new laser-based alignment system using Fresnel zone plates as the alignment targets is discussed. The transverse displacement of the focused spot of the laser is measured as a function of the displacement of the target by a detector installed at the focal point. Systematic studies on the focusing characteristics and alignment precision have been successfully conducted in this experiment. The experimental results are in good agreement with theoretical calculations, and the alignment precision of the target is determined to be less than +/-30 ?m. In this study, we perform a detailed experimental investigation on the laser propagation and focusing characteristics using the circular Fresnel zone plate at the focal region along with theoretical calculations.
Suwada, Tsuyoshi; Satoh, Masanori; Telada, Souichi; Minoshima, Kaoru
Experimental investigation on focusing characteristics of a He-Ne laser using circular Fresnel zone plate for high-precision alignment of linear accelerators
We experimentally investigate the focusing characteristics of a He-Ne laser at the focal region for the high-precision alignment of long-distance linear accelerators using a circular Fresnel zone plate. The laser wave passing through the Fresnel zone plate having a focal length of 66.7 m propagates for a 268-m-long distance at atmospheric pressure. A new laser-based alignment system using Fresnel zone plates as the alignment targets is discussed. The transverse displacement of the focused spot of the laser is measured as a function of the displacement of the target by a detector installed at the focal point. Systematic studies on the focusing characteristics and alignment precision have been successfully conducted in this experiment. The experimental results are in good agreement with theoretical calculations, and the alignment precision of the target is determined to be less than {+-}30 {mu}m. In this study, we perform a detailed experimental investigation on the laser propagation and focusing characteristics using the circular Fresnel zone plate at the focal region along with theoretical calculations.
Suwada, Tsuyoshi; Satoh, Masanori [Accelerator Laboratory, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Telada, Souichi; Minoshima, Kaoru [Length Standards Section, Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563 (Japan)
Experimental investigation on focusing characteristics of a He-Ne laser using circular Fresnel zone plate for high-precision alignment of linear accelerators.
We experimentally investigate the focusing characteristics of a He-Ne laser at the focal region for the high-precision alignment of long-distance linear accelerators using a circular Fresnel zone plate. The laser wave passing through the Fresnel zone plate having a focal length of 66.7 m propagates for a 268-m-long distance at atmospheric pressure. A new laser-based alignment system using Fresnel zone plates as the alignment targets is discussed. The transverse displacement of the focused spot of the laser is measured as a function of the displacement of the target by a detector installed at the focal point. Systematic studies on the focusing characteristics and alignment precision have been successfully conducted in this experiment. The experimental results are in good agreement with theoretical calculations, and the alignment precision of the target is determined to be less than ▒30 ?m. In this study, we perform a detailed experimental investigation on the laser propagation and focusing characteristics using the circular Fresnel zone plate at the focal region along with theoretical calculations. PMID:22667611
Suwada, Tsuyoshi; Satoh, Masanori; Telada, Souichi; Minoshima, Kaoru
High precision positioning with a sensor network
We present an experimental high-precision ultrasonic positioning system based on a sensor network. The network can track an object moving along a straight line with an accuracy of 1 cm. The bulk of the position calculation is distributed, with sensor nodes exchanging only the times-of-flight of the ultrasonic pulses, and state information.
Julio I. Concha; Jae-Hyuk Oh
High Precision Pressure Measurement with a Funnel
ERIC Educational Resources Information Center
A simple experimental device for high precision differential pressure measurements is presented. Its working mechanism recalls that of a hydraulic press, where pressure is supplied by insufflating air under a funnel. As an application, we measure air pressure inside a soap bubble. The soap bubble is inflated and connected to a funnel which isģ
Lopez-Arias, T.; Gratton, L. M.; Oss, S.
High precision laser forming for microactuation
NASA Astrophysics Data System (ADS)
For assembly of micro-devices, such as photonic devices, the precision alignment of components is often critical for their performance. Laser forming, also known as laser-adjusting, can be used to create an integrated microactuator to align the components with sub-micron precision after bonding. In this paper a so-called three-bridge planar manipulator was used to study the laser-material interaction and thermal and mechanical behavior of the laser forming mechanism. A 3-D Finite Element Method (FEM) model and experiments are used to identify the optimal parameter settings for a high precision actuator. The goal in this paper is to investigate how precise the maximum occurring temperature and the resulting displacement are predicted by a 3-D FEM model by comparing with experimental results. A secondary goal is to investigate the resolution of the mechanism and the range of motion. With the experimental setup we measure the displacement and surface temperature in real-time. The time-dependent heat transfer FEM models match closely with experimental results, however the structural model can deviate more than 100% in absolute displacement. Experimentally, a positioning resolution of 0.1?m was achieved, with a total stroke exceeding 20?m. A spread of 10% in the temperature cycles between several experiments was found, which was attributed to a spread in the surface absorptivity. Combined with geometric tolerances, the spread in displacement can be as large as 20%. This implies that feedback control of the laser power, in combination with iterative learning during positioning, is required for high precision alignment. Even though the FEM models deviate substantially from the experiments, the 3-D FEM model predicts the trend in deformation sufficiently accurate to use it for design optimization of high precision 3-D actuators using laser adjusting.
Folkersma, Ger K. G. P.; R÷mer, G. R. B. E.; Brouwer, D. M.; Huis in't Veld, A. J.
High precision redundant robotic manipulator
A high precision redundant robotic manipulator for overcoming contents imposed by obstacles or imposed by a highly congested work space is disclosed. One embodiment of the manipulator has four degrees of freedom and another embodiment has seven degrees of freedom. Each of the embodiments utilize a first selective compliant assembly robot arm (SCARA) configuration to provide high stiffness in the vertical plane, a second SCARA configuration to provide high stiffness in the horizontal plane. The seven degree of freedom embodiment also utilizes kinematic redundancy to provide the capability of avoiding obstacles that lie between the base of the manipulator and the end effector or link of the manipulator. These additional three degrees of freedom are added at the wrist link of the manipulator to provide pitch, yaw and roll. The seven degrees of freedom embodiment uses one revolute point per degree of freedom. For each of the revolute joints, a harmonic gear coupled to an electric motor is introduced, and together with properly designed based servo controllers provide an end point repeatability of less than 10 microns. 3 figs.
Young, K.K.D.
High precision redundant robotic manipulator
A high precision redundant robotic manipulator for overcoming contents imposed by obstacles or imposed by a highly congested work space. One embodiment of the manipulator has four degrees of freedom and another embodiment has seven degreed of freedom. Each of the embodiments utilize a first selective compliant assembly robot arm (SCARA) configuration to provide high stiffness in the vertical plane, a second SCARA configuration to provide high stiffness in the horizontal plane. The seven degree of freedom embodiment also utilizes kinematic redundancy to provide the capability of avoiding obstacles that lie between the base of the manipulator and the end effector or link of the manipulator. These additional three degrees of freedom are added at the wrist link of the manipulator to provide pitch, yaw and roll. The seven degrees of freedom embodiment uses one revolute point per degree of freedom. For each of the revolute joints, a harmonic gear coupled to an electric motor is introduced, and together with properly designed based servo controllers provide an end point repeatability of less than 10 microns.
Young, Kar-Keung David (Mountain View, CA)
High precision pressure measurement with a funnel
NASA Astrophysics Data System (ADS)
A simple experimental device for high precision differential pressure measurements is presented. Its working mechanism recalls that of a hydraulic press, where pressure is supplied by insufflating air under a funnel. As an application, we measure air pressure inside a soap bubble. The soap bubble is inflated and connected to a funnel which is placed, upside down, in a container filled with distilled water, placed on a scale. Our method provides a theoretical precision for the pressure measurement of the order of 0.01 Pa. Beyond this, the advantage of this method relies on the simplicity of the materials used and on the opportunity to discuss, at an undergraduate level, basic concepts regarding all those phenomena in which low or very low differential pressures are relevant.
L¾pez-Arias, T.; Gratton, L. M.; Oss, S.
High precision triangular waveform generator
An ultra-linear ramp generator having separately programmable ascending and descending ramp rates and voltages is provided. Two constant current sources provide the ramp through an integrator. Switching of the current at current source inputs rather than at the integrator input eliminates switching transients and contributes to the waveform precision. The triangular waveforms produced by the waveform generator are characterized by accurate reproduction and low drift over periods of several hours. The ascending and descending slopes are independently selectable.
Mueller, Theodore R. (Oak Ridge, TN)
High Precision Sampling for Chromatographic Separations.
National Technical Information Service (NTIS)
The precision of several chromatographic sampling values of original design is shown to approach plus or minus 0.05% for unretained solutes. Hybrid-fluidic, high pressure, and commercial valves have been characterized by measuring the precision of their c...
B. E. Bowen S. P. Cram J. E. Leitner R. L. Wade
High precision thermal neutron detectors
Two-dimensional position sensitive detectors are indispensable in neutron diffraction experiments for determination of molecular and crystal structures in biology, solid-state physics and polymer chemistry. Some performance characteristics of these detectors are elementary and obvious, such as the position resolution, number of resolution elements, neutron detection efficiency, counting rate and sensitivity to gamma-ray background. High performance detectors are distinguished by more subtle characteristics such as the stability of the response (efficiency) versus position, stability of the recorded neutron positions, dynamic range, blooming or halo effects. While relatively few of them are needed around the world, these high performance devices are sophisticated and fairly complex; their development requires very specialized efforts. In this context, we describe here a program of detector development, based on {sup 3}He filled proportional chambers, which has been underway for some years at Brookhaven. Fundamental approaches and practical considerations are outlined that have resulted in a series of high performance detectors with the best known position resolution, position stability, uniformity of reliability over time of this type.
Radeka, V.; Schaknowski, N.A.; Smith, G.C.; and Yu, B.
Precision Crystal Calorimeters in High Energy Physics
Precision crystal calorimeters traditionally play an important role in high energy physics experiments. In the last two decades, it faces a challenge to maintain its precision in a hostile radiation environment. This paper reviews the performance of crystal calorimeters constructed for high energy physics experiments and the progress achieved in understanding crystal?s radiation damage as well as in developing high quality scintillating crystals for particle physics. Potential applications of new generation scintillating crystals of high density and high light yield, such as LSO and LYSO, in particle physics experiments is also discussed.
Ren-Yuan Zhu
High-rate precise point positioning (PPP) to measure seismic wave motions: An experimental comparison of GPS PPP with inertial measurement units
NASA Astrophysics Data System (ADS)
High-rate GPS has been widely used to construct displacement waveforms and to invert for source parameters of earthquakes. Almost all works on internal and external evaluation of high-rate GPS accuracy are based on GPS relative positioning. We build an experimental platform to externally evaluate the accuracy of 50 Hz PPP displacement waveforms. Since the shake table allows motion in any of six degrees of freedom, we install an inertial measurement unit (IMU) to measure the attitude of the platform and transform the IMU displacements into the GPS coordinate system. The experimental results have shown that high-rate PPP can produce absolute horizontal displacement waveforms at the accuracy of 2 to 4 millimeters and absolute vertical displacement waveforms at the sub-centimeter level of accuracy within a short period of time. The significance of the experiments indicates that high-rate PPP is capable of detecting absolute seismic displacement waveforms at the same high accuracy as GPS relative positioning techniques but requires no fixed datum station. We have also found a small scaling error of IMU and a small time offset of misalignment between high-rate PPP and IMU displacement waveforms by comparing the amplitudes of and cross-correlating both the displacement waveforms. For more details on this talk, one can now get access to the on-line-first version of our Journal of Geodesy paper: J Geod, DOI 10.1007/s00190-012-0606-z
Xu, Peiliang; Shi, Chuang; Fang, Rongxin; Liu, Jingnan; Niu, Xiaoji; Zhang, Quan; Yanagidani, Takashi
High precision x ray lithographic masks
NASA Astrophysics Data System (ADS)
This contract period was first concerned with winding up the projects on the embedded X-ray Mask structure and on the 'quantum lithography' idea. As a result of developments elsewhere it became clear that among the most critical issues in achieving high precision X-ray masks were those associated with achieving high precision in both feature size and feature placement in electron beam lithography. Most of the effort in this reporting period was aimed at achieving precision in feature size; notably an attack on the problem of proximity effects. There were two approaches: (1) A short term approach aimed at correcting effects in existing electron beam pattern generators (notably the ETEC MEBES 3 and 4) for feature sizes down 500 nm; and (2) A long term approach aimed at avoiding proximity effects by employing low energy electron exposure for feature size below 500 nm.
Pease, R. F.; Browning, R.
Aerodynamic window for high precision laser drilling
High precision laser drilling is getting more and more interesting for industry. Main applications for such holes are vaporising and injection nozzles. To enhance quality, the energy deposition has to be accurately defined by reducing the pulse duration and thereby reducing the amount of disturbing melting layer. In addition, an appropriate processing technology, for example the helical drilling, yields holes
Steffen Sommer; Friedrich Dausinger; Peter Berger; Helmuth H³gel
High precision measurements in crustal dynamic studies
NASA Technical Reports Server (NTRS)
The development of high-precision instrumentation for monitoring benchmark stability and evaluating coseismic strain and tilt signals is reviewed. Laser strainmeter and tilt observations are presented. Examples of coseismic deformation in several geographic locations are given. Evidence suggests that the Earth undergoes elastic response to abrupt faulting.
Wyatt, F.; Berger, J.
High precision, rapid laser hole drilling
A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.
Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.
High precision Woelter optic calibration facility
We have developed an off-line facility for very precise characterization of the reflectance and spatial resolution of the grazing incidence Woelter Type 1 x-ray optics used at Nova. The primary component of the facility is a high brightness, ``point`` x-ray source consisting of a focussed DC electron beam incident onto a precision manipulated target/pinhole array. The data are recorded with a selection of detectors. For imaging measurements we use direct exposure x-ray film modules or an x-ray CCD camera. For energy-resolved reflectance measurements, we use lithium drifted silicon detectors and a proportional counter. An in situ laser alignment system allows precise location and rapid periodic alignment verification of the x-ray point source, the statically mounted Woelter optic, and the chosen detector.
Morales, R.I.; Remington, B.A.; Schwinn, T.
High precision localization methods for HZE-particles
For experimental investigations in the field of microdosimetry of heavy ions a high precision localization method for biological objects relative to the path of the penetrating ion is mandatory. New methods are described for corn seeds of Arabidopsis thaliana and spores of Bacillus subtilis. In the latter case the actual penetration point of the particle in the spore layer is
M. Schõfer; H. B³cker; R. Facius; D. Hildebrand
High-precision hydraulic Stewart platform
NASA Astrophysics Data System (ADS)
We present a novel design for a Stewart platform (or hexapod), an apparatus which performs positioning tasks with high accuracy. The platform, which is supported by six hydraulic telescopic struts, provides six degrees of freedom with 1 ?m resolution. Rotations about user defined pivot points can be specified for any axis of rotation with microradian accuracy. Motion of the platform is performed by changing the strut lengths. Servo systems set and maintain the length of the struts to high precision using proportional hydraulic valves and incremental encoders. The combination of hydraulic actuators and a design which is optimized in terms of mechanical stiffness enables the platform to manipulate loads of up to 20 kN. Sophisticated software allows direct six-axis positioning including true path control. Our platform is an ideal support structure for a large variety of scientific instruments that require a stable alignment base with high-precision motion.
van Silfhout, Roelof G.
Portable high precision pressure transducer system
A high precision pressure transducer system is described for checking the reliability of a second pressure transducer system used to monitor the level of a fluid confined in a holding tank. Since the response of the pressure transducer is temperature sensitive, it is continually housed in an battery powered oven which is configured to provide a temperature stable environment at specified temperature for an extended period of time. Further, a high precision temperature stabilized oscillator and counter are coupled to a single board computer to accurately determine the pressure transducer oscillation frequency and convert it to an applied pressure. All of the components are powered by the batteries which during periods of availability of line power are charged by an on board battery charger. The pressure readings outputs are transmitted to a line printer and a vacuum fluorescent display. 2 figures.
Piper, T.C.; Morgan, J.P.; Marchant, N.J.; Bolton, S.M.
Portable high precision pressure transducer system
A high precision pressure transducer system for checking the reliability of a second pressure transducer system used to monitor the level of a fluid confined in a holding tank. Since the response of the pressure transducer is temperature sensitive, it is continually housed in an battery powered oven which is configured to provide a temperature stable environment at specified temperature for an extended period of time. Further, a high precision temperature stabilized oscillator and counter are coupled to a single board computer to accurately determine the pressure transducer oscillation frequency and convert it to an applied pressure. All of the components are powered by the batteries which during periods of availability of line power are charged by an on board battery charger. The pressure readings outputs are transmitted to a line printer and a vacuum florescent display.
Piper, Thomas C. (Idaho Falls, ID); Morgan, John P. (Idaho Falls, ID); Marchant, Norman J. (Idaho Falls, ID); Bolton, Steven M. (Pocatello, ID)
Portable high precision pressure transducer system
NASA Astrophysics Data System (ADS)
A high precision pressure transducer system for checking the reliability of a second pressure transducer system used to monitor the level of a fluid confined in a holding tank is presented. Since the response of the pressure transducer is temperature sensitive, it is continually housed in a battery powered oven which is configured to provide a temperature stable environment at specified temperature for an extended period of time. Further, a high precision temperature stabilized oscillator and counter are coupled to a single board computer to accurately determine the pressure transducer oscillation frequency and convert it to an applied pressure. All of the components are powered by the batteries which during periods of availability of line power are charged by an on-board battery charger. The pressure readings outputs are transmitted to a line printer and a vacuum fluorescent display.
Piper, T. C.; Morgan, J. P.; Marchant, N. J.; Bolton, S. M.
Measurement and Precision: High School Activity
NSDL National Science Digital Library
This activity from the Florida Advanced Technological Education (FL-ATE) Center asks students to use the concepts of measurement and precision in the context of designing and manufacturing surgical instruments. The interdisciplinary lesson plan involves science, computer technology, math and technical education. Students will have the opportunity to develop their understanding of number systems and their application in the context of a practical industrial situation. This version of the lesson is appropriate for high school aged students.
Fiber Scrambling for High Precision Spectrographs
NASA Astrophysics Data System (ADS)
The detection of Earth-like exoplanets with the radial velocity method requires extreme Doppler precision and long-term stability in order to measure tiny reflex velocities in the host star. Recent planet searches have led to the detection of so called "super-Earthsö (up to a few Earth masses) that induce radial velocity changes of about 1 m/s. However, the detection of true Earth analogs requires a precision of 10 cm/s. One of the largest factors limiting Doppler precision is variation in the Point Spread Function (PSF) from observation to observation due to changes in the illumination of the slit and spectrograph optics. Thus, this stability has become a focus of current instrumentation work. Fiber optics have been used since the 1980's to couple telescopes to high-precision spectrographs, initially for simpler mechanical design and control. However, fiber optics are also naturally efficient scramblers. Scrambling refers to a fiber's ability to produce an output beam independent of input. Our research is focused on characterizing the scrambling properties of several types of fibers, including circular, square and octagonal fibers. By measuring the intensity distribution after the fiber as a function of input beam position, we can simulate guiding errors that occur at an observatory. Through this, we can determine which fibers produce the most uniform outputs for the severest guiding errors, improving the PSF and allowing sub-m/s precision. However, extensive testing of fibers of supposedly identical core diameter, length and shape from the same manufacturer has revealed the "personalityö of individual fibers. Personality describes differing intensity patterns for supposedly duplicate fibers illuminated identically. Here, we present our results on scrambling characterization as a function of fiber type, while studying individual fiber personality.
Kaplan, Zachary; Spronck, J. F. P.; Fischer, D.
Adventures in High Precision Laser Spectroscopy
Optical frequency comb techniques are revolutionizing the art of measuring the frequency of light. The complex and highly specialized harmonic laser frequency chains of the past can now be replaced by a universal optical frequency comb synthesizer using just a single mode-locked femtosecond laser. After spectral broadening in a nonlinear optical fiber, such a laser emits a regular comb of hundred of thousands of evenly spaced sharp laser lines, extending throughout the visible and near infrared spectrum. The frequency of each line can be determined by radio frequency methods with extreme precision. Such frequency comb synthesizers are already revolutionizing precision laser spectroscopy, they provide the clock work for novel ultraprecise atomic clocks, based on optical transitions in atoms, ions or molecules, and they open new frontiers for stringent tests of fundamental physics laws.
Precision mass measurements of highly charged ions
NASA Astrophysics Data System (ADS)
The reputation of Penning trap mass spectrometry for accuracy and precision was established with singly charged ions (SCI); however, the achievable precision and resolving power can be extended by using highly charged ions (HCI). The TITAN facility has demonstrated these enhancements for long-lived (T1/2>=50 ms) isobars and low-lying isomers, including ^71Ge^21+, ^74Rb^8+, ^78Rb^8+, and ^98Rb^15+. The Q-value of ^71Ge enters into the neutrino cross section, and the use of HCI reduced the resolving power required to distinguish the isobars from 3 x 10^5 to 20. The precision achieved in the measurement of ^74Rb^8+, a superallowed ?-emitter and candidate to test the CVC hypothesis, rivaled earlier measurements with SCI in a fraction of the time. The 111.19(22) keV isomeric state in ^78Rb was resolved from the ground state. Mass measurements of neutron-rich Rb and Sr isotopes near A = 100 aid in determining the r-process pathway. Advanced ion manipulation techniques and recent results will be presented.
Kwiatkowski, A. A.; Bale, J. C.; Brunner, T.; Chaudhuri, A.; Chowdhury, U.; Ettenauer, S.; Frekers, D.; Gallant, A. T.; Grossheim, A.; Lennarz, A.; Mane, E.; MacDonald, T. D.; Schultz, B. E.; Simon, M. C.; Simon, V. V.; Dilling, J.
High precision kinematic surveying with laser scanners
NASA Astrophysics Data System (ADS)
The kinematic survey of roads and railways is becoming a much more common data acquisition method. The development of the Mobile Road Mapping System (MoSES) has reached a level that allows the use of kinematic survey technology for high precision applications. The system is equipped with cameras and laser scanners. For high accuracy requirements, the scanners become the main sensor group because of their geometric precision and reliability. To guarantee reliable survey results, specific calibration procedures have to be applied, which can be divided into the scanner sensor calibration as step 1, and the geometric transformation parameter estimation with respect to the vehicle coordinate system as step 2. Both calibration steps include new methods for sensor behavior modeling and multisensor system integration. To verify laser scanner quality of the MoSES system, the results are regularly checked along different test routes. It can be proved that a standard deviation of 0.004 m for height of the scanner points will be obtained, if the specific calibrations and data processing methods are applied. This level of accuracy opens new possibilities to serve engineering survey applications using kinematic measurement techniques. The key feature of scanner technology is the full digital coverage of the road area. Three application examples illustrate the capabilities. Digital road surface models generated from MoSES data are used, especially for road surface reconstruction tasks along highways. Compared to static surveys, the method offers comparable accuracy at higher speed, lower costs, much higher grid resolution and with greater safety. The system's capability of gaining 360 profiles leads to other complex applications like kinematic tunnel surveys or the precise analysis of bridge clearances.
Grõfe, Gunnar
High precision innovative micropump for artificial pancreas
NASA Astrophysics Data System (ADS)
The concept of artificial pancreas, which comprises an insulin pump, a continuous glucose meter and a control algorithm, is a major step forward in managing patient with type 1 diabetes mellitus. The stability of the control algorithm is based on short-term precision micropump to deliver rapid-acting insulin and to specific integrated sensors able to monitor any failure leading to a loss of accuracy. Debiotech's MEMS micropump, based on the membrane pump principle, is made of a stack of 3 silicon wafers. The pumping chamber comprises a pillar check-valve at the inlet, a pumping membrane which is actuated against stop limiters by a piezo cantilever, an anti-free-flow outlet valve and a pressure sensor. The micropump inlet is tightly connected to the insulin reservoir while the outlet is in direct communication with the patient skin via a cannula. To meet the requirement of a pump dedicated to closed-loop application for diabetes care, in addition to the well-controlled displacement of the pumping membrane, the high precision of the micropump is based on specific actuation profiles that balance effect of pump elasticity in low-consumption push-pull mode.
Chappel, E.; Mefti, S.; Lettieri, G.-L.; Proennecke, S.; Conan, C.
A High Precision Experiment of the Buckling of Spherical Caps Subjected to External Pressure.
National Technical Information Service (NTIS)
A high precision experiment has been carried out to bridge the gap between the theoretical and experimental buckling loads of spherical caps subjected to external pressure. The details of the forming process of test specimens, experimental arrangements an...
M. Sunakawa K. Ichida
Highly damped kinematic coupling for precision instruments
A highly damped kinematic coupling for precision instruments. The kinematic coupling provides support while causing essentially no influence to its nature shape, with such influences coming, for example, from manufacturing tolerances, temperature changes, or ground motion. The coupling uses three ball-cone constraints, each combined with a released flexural degree of freedom. This arrangement enables a gain of higher load capacity and stiffness, but can also significantly reduce the friction level in proportion to the ball radius divided by the distance between the ball and the hinge axis. The blade flexures reduces somewhat the stiffness of the coupling and provides an ideal location to apply constrained-layer damping which is accomplished by attaching a viscoelastic layer and a constraining layer on opposite sides of each of the blade flexures. The three identical ball-cone flexures provide a damped coupling mechanism to kinematically support the projection optics system of the extreme ultraviolet lithography (EUVL) system, or other load-sensitive apparatus.
Hale, Layton C. (Livermore, CA); Jensen, Steven A. (Livermore, CA)
High precision droplet based new form manufacturing
In collaboration with the University of California at Irvine (UCI), we are working on a new technology that relies on the precise deposition of nanoliter molten-metal droplets that are targeted onto a substrate by electrostatic charging and deflection. By this way, three-dimensional (3D) structural materials can be manufactured microlayer by microlayer. Because the volume of the droplets are small, they rapidly solidify on impact, bringing forth a material component with fine grain structures which lead to enhanced material properties (e.g., strength). UCI is responsible for an experimental investigation of the manufacturing feasibility of this process. LLNL has unique expertise in the computational modeling of 3D heat transfer and solid mechanics and has the large-scale computer resources necessary to model this large system. Process modeling will help move this technology from the bench-top to an industrial process. Applications at LLNL include rapid prototyping of metal parts and manufacturing new alloys by co-jetting different metals.
Aceves,S; Hadjiconstantinou, N; Miller, W O; Orme, M; Sahai, V; Shapiro, A B
High precision beam alignment of electromagnetic wigglers
The performance of Free-Electron Lasers depends critically on the quality of the alignment of the electron beam to the wiggler's magnetic axis and the deviation of this axis from a straight fine. The measurement of the electron beam position requires numerous beam position monitors in the wiggler, where space is at premium. The beam position measurement is used to set beam steerers for an orbit correction in the wiggler. The authors propose an alternative high precision alignment method in which one or two external Beam Position Monitors (BPM) are used. In this technique, the field in the electro-wiggler is modulated section by section and the beam position movement at the external BPM is detected in synchronism with the modulation. A beam offset at the modulated beam section will produce a modulation of the beam position at the detector that is a function of the of the beam offset and the absolute value of the modulation current. The wiggler errors produce a modulation that is a function of the modulation current. It will be shown that this method allows the detection and correction of the beam position at each section in the presence of wiggler errors with a good resolution. Furthermore, it allows one to measure the first and second integrals of the wiggler error over each wiggler section. Lastly, provided that wiggler sections can be degaussed effectively, one can test the deviation of the wiggler's magnetic axis from a straight line.
Ben-Zvi, I.; Qiu, X.Z.
Mechatronics Framework for High Precision Machining.
National Technical Information Service (NTIS)
The development of a new mechatronic tool holder system that is capable of fast and precise local tool adjustments based on sensory feedbacks is proposed. Central to this development is the use of magnetic servo levitation for driving the tool as well as ...
P. I. Ro
Advanced gravitational reference sensor for high precision space interferometers
LISA and the next generation of space-based laser interferometers require gravitational reference sensors (GRS) to provide distance measurements to picometre precision for LISA, and femtometre precision for the proposed Big Bang Observatory (BBO). We describe a stand-alone GRS structure that has the benefits of higher sensitivity and ease of fabrication. The proposed GRS structure enables high precision interferometric links in
Ke-Xun Sun; Graham Allen; Sasha Buchman; Dan DeBra; Robert Byer
High-precision triangular-waveform generator
An ultra-linear ramp generator having separately programmable ascending and decending ramp rates and voltages is provided. Two constant current sources provide the ramp through an integrator. Switching of the current at current source inputs rather than at the integrator input eliminates switching transients and contributes to the waveform precision. The triangular waveforms produced by the waveform generator are characterized by accurate reproduction and low drift over periods of several hours. The ascending and descending slopes are independently selectable.
Mueller, T.R.
Ultra-High-Precision Machining Techniques: Applications and Current Status.
National Technical Information Service (NTIS)
The article describes in general the applications of ultra-high precision machining techniques in present-day high-technology product manufacturing. Moreover, a general account is given of principal methods and means of implementing ultra-high-precision m...
X. Xin
High-precision thorium RIMS for geochemistry
We present our latest results in the development of resonance ionization mass spectrometry (RIMS) using cw lasers to measure isotope ratios of importance in geochemistry and geochronology. The RIMS method provides a higher ionization efficiency than thermal ionization allowing analysis of smaller sample sizes, while maintaining equivalent internal precision. The bias introduced in {sup 230/232}Th ratio measurements by the RIMS method when using narrow-band and broad-band lasers is discussed. Spectra of {sup 239}Th, which can be used as an internal standard, are also presented.
Fearey, B.L.; Tissue, B.M.; Olivares, J.A.; Loge, G.W.; Murrell, M.T.; Miller, C.M.
High-precision thorium RIMS for geochemistry
We present our latest results in the development of resonance ionization mass spectrometry (RIMS) using cw lasers to measure isotope ratios of importance in geochemistry and geochronology. The RIMS method provides a higher ionization efficiency than thermal ionization allowing analysis of smaller sample sizes, while maintaining equivalent internal precision. The bias introduced in {sup 230/232}Th ratio measurements by the RIMS method when using narrow-band and broad-band lasers is discussed. Spectra of {sup 239}Th, which can be used as an internal standard, are also presented.
Fearey, B.L.; Tissue, B.M.; Olivares, J.A.; Loge, G.W.; Murrell, M.T.; Miller, C.M.
A high precision telescope pointing system
NASA Astrophysics Data System (ADS)
A novel method of telescope pointing has been developed based on He-Ne laser interferometric measurements of mirror position. This technique has been applied to a Pfund-type telescope, which consists of a fixed parabolic mirror illuminated by a flat mirror which rotates in altitude and azimuth. If the parabolic mirror is stationary, the angle of pointing depends only on the change of orientation of the flat mirror with respect to the parabolic mirror. The relative angles of mirrors with radius of 1 meter are measured to a precision of about 0.05 arcsec. Fluctuations in the index of refraction of the atmosphere between the mirrors are the primary source of this limit; however, changes in pointing position involving only a gradient in the index of refraction perpendicular to the optic axis are largely compensated by this pointing technique. Conversion of interference fringe counts to precise angle of pointing involves solutions of equations of modest complexity, but is easily handled by a small computer.
Danchi, W. C.; Arthur, A.; Fulton, R.; Peck, M.; Sadoulet, B.
High contrast gratings for high-precision metrology
NASA Astrophysics Data System (ADS)
Experiments in the field of high-precision optical metrology are crucially limited by thermal noise of the optical components such as mirrors or beam splitters. Amorphous coatings stacks are found to be a main source for these thermal fluctuations. In this contribution we present approaches to realize coating free optical components based on resonant high contrast gratings (HCGs) made of crystalline silicon. It is shown that beside classical cavity mirrors the concept of HCGs can also be used for reflective cavity couplers. We compare the advantages and challenges of these HCG reflectors with distributed Bragg reflectors made of crystalline coatings for applications in optical metrology.
Kroker, Stefanie; Steiner, Stefan; Kõsebier, Thomas; Kley, Ernst-Bernhard; T³nnermann, Andreas
Advanced gravitational reference sensor for high precision space interferometers
NASA Astrophysics Data System (ADS)
LISA and the next generation of space-based laser interferometers require gravitational reference sensors (GRS) to provide distance measurements to picometre precision for LISA, and femtometre precision for the proposed Big Bang Observatory (BBO). We describe a stand-alone GRS structure that has the benefits of higher sensitivity and ease of fabrication. The proposed GRS structure enables high precision interferometric links in three-dimensional directions. The GRS housing provides the optical reference surface onto which the transmitted laser beam, and the independent received laser beam are referenced. The stand-alone GRS allows balanced optical probing of the distance of the proof mass relative to the housing at a power and wavelength that differ from the transmitted and received wavelengths and with picometre sensitivity without radiation pressure imbalance. The single parameter that reduces proof mass disturbance forces is the gap spacing. Optical readout allows the use of a large gap between the GRS housing and proof mass. We propose using rf-modulated optical interferometry to measure both relative displacement and absolute distance. Further we propose to use a reflective grating beamsplitter within the GRS and on the external optical bench. The reflective grating design eliminates the in-path transmissive optical components and the dn/dT related optical path effects, and simplifies the optical bench structure. Inside the GRS, a near-Littrow mounted grating enables picometre precision measurement at microwatts of optical power. Preliminary experimental results using a grating beamsplitter interferometer are presented, which demonstrate an optical sensing sensitivity of 30 pm Hz-1/2.
Sun, Ke-Xun; Allen, Graham; Buchman, Sasha; DeBra, Dan; Byer, Robert
High precision fiber SINS with spin technology
NASA Astrophysics Data System (ADS)
Fiber strapdown inertial navigation system (FSINS) is presently used in several applications related to marine navigation. However, the absolute position from FSINS contains the error that increases with time, which prevents its long-term use for the ship cruise. In order to improve the performance of FSINS based on our present inertial sensors, the spin technology was proposed in the system to mitigate the navigation errors and a prototype of the proposed system was developed in Navigation Lab. The prototype contains the IMU, temperature controller, rotating configuration, navigation and I/O electronics group, control and display, power supply subsystem and other modules. In the proposed spin technology, the IMU is rotated back and forth in azimuth through four orthogonal positions relative to the ship's longitudinal axis. Experimental testing was conducted for the prototype in the laboratory and the results showed that the RFSINS's navigation performance is improved 10 times.
Sun, Wei; Sun, Feng; Wang, Da-xue
Thermomechanically Driven Polymer Actuator for High-Precision Optical Alignment
Precise thermomechanical positioning has been demonstrated in an actuator device based on a silicone elastomer with a high thermal expansion coefficient. The actuator performance has been characterized using optical microscopy, and the actuator has been deployed in an optical coupling experiment to demonstrate the precise positioning of a ball lens between two single-mode fibers. Tuning of the coupling efficiency has
G. Jordan; A. M. Lyons
Development of pneumatic high precise position controllable servo valve
We developed a pneumatic high precise position controllable servo valve for a pneumatic precise positioning system. To improve the performance of a pneumatic, improvement of the servo valve characteristic is essential because the system performance is dominated by it. This valve is not affected by friction force because an air bearing is mounted on sliding surfaces of the valve. Furthermore,
Takashi Miyajima; Kazutoshi Sakaki; Takashi Shibukawa; T. Fujita; K. Kawashima; T. Kagawa
High precision defocused observations of planetary transits
NASA Astrophysics Data System (ADS)
It is only possible to measure physical properties of extrasolar planets, if they transit their host stars. One can determine the masses and the radii of this kind of objects, and hence, have constraints on their chemical composition, internal structure, formation and evolution. The availability of high quality light curves of planetary transits is essential in determining these properties within a few percent. In order to obtain high-quality transit light curves, we apply the well-established defocus technique on meter and sub-meter class telescopes in our project. This technique allows longer integration times, and hence collecting more photons to build up a higher S/N ratio. In this study, we present our first photometric results with the 1m Turkish telescope (T100) located at T▄B?TAK National Observatory (TUG) of Turkey, which proved to be a well suited instrument to these observations with its large field of view. %
Ba?t³rk, ų.; Hinse, T. C.; ųzavc?, ?.; Tezcan, C. T.; ?enavc?, H. V.; Burdanov, A.; Y&÷r³ko?lu, O.; Orhan, R.; Selam, S. O.
Experimental evaluation of uncalibrated visual servoing for precision manipulation
We present an experimental evaluation of adaptive and non-adaptive visual servoing in 3, 6 and 12 degrees of freedom (DOF), comparing it to traditional joint feedback control. While the purpose of experiments in most other work has been to show that the particular algorithm presented indeed also works in practice, we do not focus on the algorithm but rather on
Martin Jagersand; Olac Fuentes; Randal Nelson
High-precision x-ray spectroscopy of highly charged ions with microcalorimeters
NASA Astrophysics Data System (ADS)
The precise determination of the energy of the Lyman ?1 and ?2 lines in hydrogen-like heavy ions provides a sensitive test of quantum electrodynamics in very strong Coulomb fields. To improve the experimental precision, the new detector concept of microcalorimeters is now exploited for such measurements. Such detectors consist of compensated-doped silicon thermistors and Pb or Sn absorbers to obtain high quantum efficiency in the energy range of 40-70 keV, where the Doppler-shifted Lyman lines are located. For the first time, a microcalorimeter was applied in an experiment to precisely determine the transition energy of the Lyman lines of lead ions at the experimental storage ring at GSI. The energy of the Ly ?1 line E(Ly-?1, 207Pb81+) = (77937 ▒ 12stat ▒ 25syst) eV agrees within error bars with theoretical predictions. To improve the experimental precision, a new detector array with more pixels and better energy resolution was equipped and successfully applied in an experiment to determine the Lyman-? lines of gold ions 197Au78+.
Kraft-Bermuth, S.; Andrianov, V.; Bleile, A.; Echler, A.; Egelhof, P.; Grabitz, P.; Ilieva, S.; Kilbourne, C.; Kiselev, O.; McCammon, D.; Meier, J.
A Comparison of three high-precision quadrature schemes
The authors have implemented three numerical quadrature schemes, using the new Arbitrary Precision (ARPREC) software package, with the objective of seeking a completely ''automatic'' arbitrary precision quadrature facility, namely one that does not rely on a priori information of the function to be integrated. Such a facility is required, for example, to permit the experimental identification of definite integrals based on their numerical values. The performance and accuracy of these three quadrature schemes are compared using a suite of 15 integrals, ranging from continuous, well-behaved functions on finite intervals to functions with vertical derivatives and integrable singularities at endpoints, as well as several integrals on an infinite interval.
Bailey, David H.; Li, Xiaoye S.
Experimental Dynamic Characterization of a Reconfigurable Adaptive Precision Truss
NASA Technical Reports Server (NTRS)
The dynamic behavior of a reconfigurable adaptive truss structure with non-linear joints is investigated. The objective is to experimentally examine the effects of the local non-linearities on the global dynamics of the structure. Amplitude changes in the frequency response functions are measured at micron levels of motion. The amplitude and frequency variations of a number of modes indicate a non-linear Coulomb friction response. Hysteretic bifurcation behavior is also measured at an amplitude approximately equal to the specified free-play in the joint. Under the 1 g pre-load, however, the non-linearity was dominantly characteristic of Coulomb friction with little evidence of free-play stiffening.
Hinkle, J. D.; Peterson, L. D.
Towards a precision spectroscopy of very highly charged ions by employing dielectronic recombination
The measurement of dielectronic recombination (DR) with high energy resolution provides a unique tool for precision spectroscopy of intermediate doubly excited states of very highly charged ions. One of our experimental goals at the experimental storage ring (ESR) of GSI is the determination of the 2s12-2p12 energy splitting ? in high-Z Li-like ions. This requires electron-ion center-of-mass energies for DR
W. Spies; O. Uwira; A. M³ller; J. Linkemann; L. Empacher; A. Frank; C. Kozhuharov; P. H. Mokler; F. Bosch; O. Klepper; B. Franzke; M. Steck
Theoretical and experimental analysis of nano-surface generation in ultra-precision raster milling
The fabrication of high-quality freeform surfaces is based on ultra-precision raster milling, which allows direct machining of the freeform surfaces with sub-micrometric form accuracy and nanometric surface finish. Ultra-precision raster milling is an emerging manufacturing technology for the fabrication of high-precision and high-quality components with a surface roughness of less than 10nm and a form error of less than 0.2?m
M. N. Cheng; C. F. Cheung; W. B. Lee; S. To; L. B. Kong
High-precision digital ? counting for superallowed ?-decay studies
NASA Astrophysics Data System (ADS)
Superallowed ?-decay ft values must be measured to high precision in order to test the Electroweak Standard Model and probe new physics beyond it. To establish a more robust ? counting system for high precision half-life measurements, we have developed a new digital ? counting system, which we have now tested on-line. An 8-bit digitizer with 1 GS/s sampling rate was used to record the waveforms from our gas proportional counter, and a software filter applied to discriminate and count genuine decay events. The software filter uses pulse-shape analysis to separate genuine ?-decay events from proportional-counter spurious pulses. The digital counting method and the results obtained from our recent on-line test experiments will be presented in detail. This work demonstrates the first successful application of a high-speed digitizer and off-line digital-signal-processing techniques to high precision nuclear ?-decay lifetime measurements.
Chen, Lixin; Hardy, John C.
High precision spectroscopy and imaging in THz frequency range
NASA Astrophysics Data System (ADS)
Application of microwave methods for development of the THz frequency range has resulted in elaboration of high precision THz spectrometers based on nonstationary effects. The spectrometers characteristics (spectral resolution and sensitivity) meet the requirements for high precision analysis. The gas analyzers, based on the high precision spectrometers, have been successfully applied for analytical investigations of gas impurities in high pure substances. These investigations can be carried out both in absorption cell and in reactor. The devices can be used for ecological monitoring, detecting the components of chemical weapons and explosive in the atmosphere. The great field of THz investigations is the medicine application. Using the THz spectrometers developed one can detect markers for some diseases in exhaled air.
Vaks, Vladimir L.
High-precision thermal and electrical characterization of thermoelectric modules.
This paper describes an apparatus for performing high-precision electrical and thermal characterization of thermoelectric modules (TEMs). The apparatus is calibrated for operation between 20?░C and 80?░C and is normally used for measurements of heat currents in the range 0-10 W. Precision thermometry based on miniature thermistor probes enables an absolute temperature accuracy of better than 0.010?░C. The use of vacuum isolation, thermal guarding, and radiation shielding, augmented by a careful accounting of stray heat leaks and uncertainties, allows the heat current through the TEM under test to be determined with a precision of a few mW. The fractional precision of all measured parameters is approximately 0.1%. PMID:24880397
Kolodner, Paul
High-precision thermal and electrical characterization of thermoelectric modules
NASA Astrophysics Data System (ADS)
This paper describes an apparatus for performing high-precision electrical and thermal characterization of thermoelectric modules (TEMs). The apparatus is calibrated for operation between 20 ░C and 80 ░C and is normally used for measurements of heat currents in the range 0-10 W. Precision thermometry based on miniature thermistor probes enables an absolute temperature accuracy of better than 0.010 ░C. The use of vacuum isolation, thermal guarding, and radiation shielding, augmented by a careful accounting of stray heat leaks and uncertainties, allows the heat current through the TEM under test to be determined with a precision of a few mW. The fractional precision of all measured parameters is approximately 0.1%.
Kolodner, Paul
High precision boundary fractal analysis for shape characterization
NASA Astrophysics Data System (ADS)
Numerous kinds of particles in geological and environmental sciences may be characterized by their boundary fractal dimension. Several methods are available: structured walk, box-counting, dilation and euclidean distance mapping (EDM). The precision and stability of these techniques is variable and usually low precision fractal dimensions are obtained (▒0.1). Validation on mathematical fractals and tests of the effects of pixelization, size, resolution and topology were performed with three computer-derived methods (box-counting, dilation and EDM), using mathematical objects and fragments coming from impact and ore deposits breccias. Tests demonstrate that high precision results can be yielded with the right technique and caution. EDM showed the highest precision (▒0.01) and strongest reliability with less sensitivity to size and resolution, with reproducible results for fragments as small as 10,000 pixels of area. It was also the most accurate for mathematical fractals.
Bķrubķ, Dominique; Jķbrak, Michel
A high precision range-gate circuit designed with CPLD
NASA Astrophysics Data System (ADS)
The range-gate control circuit is one of the most important components of SLR (satellite laser ranging) technology, which can greatly improve the successful probability of SLR. A high precision range-gate control circuit designed with CPLD (complex programmable logical device) is introduced, in which VHDL (very high speed integrated circuit hardware description language) is adopted to design the internal architecture of CPLD and make CPLD work harmoniously with single-chip processor and personal computer, thereby realizing the high-precision range-gate control circuit.
Han, Hong; Wu, Zhi-Bo; Zhang, Zhong-Ping; Chen, Ju-Ping
Adventures in High Precision Laser Spectroscopy (How to measure the frequency of light with extreme precision)
Optical frequency comb techniques are revolutionizing the art of measuring the frequency of light. The complex and highly specialized harmonic laser frequency chains of the past can now be replaced by a universal optical frequency comb synthesizer using just a single mode-locked femtosecond laser. After spectral broadening in a nonlinear optical fiber, such a laser emits a regular comb of hundred of thousands of evenly spaced sharp laser lines, extending throughout the visible and near infrared spectrum. The frequency of each line can be determined by radio frequency methods with extreme precision. Such frequency comb synthesizers are already revolutionizing precision laser spectroscopy, they provide the clock work for novel ultraprecise atomic clocks, based on optical transitions in atoms, ions or molecules, and they open new frontiers for stringent tests of fundamental physics laws.
Testing a collision avoidance display with high-precision navigation
NASA Astrophysics Data System (ADS)
Recent years have seen a rise in sophisticated navigational positioning techniques. Starting from classical GPS, differential GPS, ground-based augmentation, and raw data submission have opened possibilities for high precision lateral positioning for beyond what was thinkable before. This yields new perspectives for technologies like ACAS/TCAS, by enabling last-minute lateral avoidance as a supplement to the established vertical avoidance maneuvers. Working together with Ohio University's Avionics Department, DLR has developed and tested a set of displays for situational awareness and lateral last-minute avoidance in a collision situation, implementing some state-of-the art ideas in collision avoidance. The displays include the possibility to foresee the hazard zone of a possible intruder and thus avoid that zone early. The displays were integrated into Ohio University's experimental airplane, and a flight experiment was conducted to make a first evaluation of the applicability. The tests were carried out in fall 2012. We will present the principal architecture of the displays and detail the implementation into the flight carrier. Furthermore, we will give first results of the displays' performance.
Peinecke, Niklas; Uijt de Haag, Maarten; Meysel, Frederik; Duan, Pengfei; K³ppers, Rene; Beernink, Bram
High Precision Pointing Stability and Control for Exoplanet Missions
NASA Astrophysics Data System (ADS)
Exoplanet imaging and characterization space observatories require high precision pointing stability and stability. We have developed a toolbox of sensors, actuators and algorithms along with a systems approach to meet the demanding needs of these missions. Grown from developments and experience gained from high precision Earth remote sensing missions such as the WorldView satellites, as well as high performance astrophysics missions such as Kepler and JWST, these capabilities are enabling for a wide range of future missions. The approaches take advantage of highly flexible software architectures; Enhanced ground simulation capabilities for system tuning and verification and validation; Testing capabilities to verify our modelling; High precision sensors including sub-arc-second star trackers and fine guidance sensors; High bandwidth fast steering mirrors for optical path control; and high precision reaction wheels and control moment gyros for overall observatory control. Many of these capabilities coupled with innovative thinking have been applied to the recent Kepler mission to enable the K2 extended mission concept.
Barnes, Arnold; Troeltzsch, John; Wiemer, Doug
New technique of machining high precision mirror surface press roller
NASA Astrophysics Data System (ADS)
High precision mirror surface press roller machining technique of corrosion and grinding proof is one of the key techniques that the production enterprises as well as the machining and manufacturing of the following industries sought to resolve for a long time: plastics, papermaking, rubber, film, and chip production. In Oct. 1984, a new comprehensive machining technique of metal brush coating, grinding with abrasive belt, as well as buffing was used to conduct nearly 20 experiments. In Jan. 1985, a pair of middle convex high precision mirror surface press rollers was successfully machined. The technical process is described.
Hongsen, Deng
Precision glass molding: an integrative approach for the production of high precision micro-optics
NASA Astrophysics Data System (ADS)
Miniaturization and integration are the dominating factors for the success of numerous optical devices. Conventional manufacturing processes for the fabrication of precise glass optics by means of grinding and polishing cannot cope the increasing demands in terms of precision, volume and costs. Here, precision glass molding is the enabling technology to meet these demands of the future optical products and applications. Since the market requests further miniaturization and integration of the micro optical components the possession of the entire sequence of processes is absolutely essential. With the accomplished and ongoing developments at the Fraunhofer IPT, the replication of double-sided (a)spherical and (a)cylindrical glass lenses with form accuracies of < 150 nm as well as lens arrays and even freeform optics could be realized. Therefore, a sequence of processes needs to be passed. The FEM-simulation of the molding process which was driven to a point capable to simulate even the molding of freeform optics is the first process step. Further on, new mold design concepts were generated to enable the replication of free formed optics. The research works focusing on the mold manufacturing led to sophisticated grinding process strategies able to realized complex mold geometries such as lens arrays. With regard to the coating of the molds, proceedings were developed assuring a defect free and uniform coating which enables the longevity of the molds and therewith helps reducing the final costs per lens. Thus, the precision glass molding becomes more and more interesting even for highly complex mid volume lots, characteristic for European or US optics manufacturer.
H³nten, Martin; Klocke, Fritz; Dambon, Olaf
Precision high voltage divider for the KATRIN experiment
NASA Astrophysics Data System (ADS)
The Karlsruhe Tritium Neutrino (KATRIN) experiment aims to determine the absolute mass of the electron antineutrino from a precise measurement of the tritium ?-spectrum near its endpoint at 18.6 keV with a sensitivity of 0.2 eV c-2. KATRIN uses an electrostatic retardation spectrometer of MAC-E filter type for which it is crucial to monitor high voltages of up to 35 kV with a precision and long-term stability at the ppm level. Since devices capable of this precision are not commercially available, a new high voltage divider for direct voltages of up to 35 kV has been designed, following the new concept of the standard divider for direct voltages of up to 100 kV developed at the Physikalisch-Technische Bundesanstalt (PTB)PTB is the German National Metrology Institute providing scientific and technical services.. The electrical and mechanical design of the divider, the screening procedure for the selection of the precision resistors, and the results of the investigation and calibration at the PTB are reported here. During the latter, uncertainties at the low ppm level have been deduced for the new divider, thus qualifying it for the precision measurements of the KATRIN experiment.
Th³mmler, Th; Marx, R.; Weinheimer, Ch
A high precision Fabry-Perot cavity polarimeter at HERA
A Fabry-Perot cavity polarimeter, installed in 2003 at HERA for the second phase of its operation, is described. The cavity polarimeter was designed to measure the longitudinal polarisation of the HERA electron beam with high precision for each electron bunch spaced with a time interval of 96 ns. Within the cavity the laser intensity was routinely enhanced up to a
S. Baudrand; M. Bouchel; V. Brisson; R. Chiche; M. Jacquet; S. Kurbasov; G. Li; C. Pascaud; A. Reboux; V. Soskov; Z. Zhang; F. Zomer; M. Beckingham; T. Behnke; N. Coppola; N. Meyners; D. Pitzl; S. Schmitt; M. Authier; P. Deck-Betinelli; Y. Queinec; L. Pinard
Design of a High Precision Dilatometer Using Laser Interferometry.
National Technical Information Service (NTIS)
This study examines the design of a high precision dilatometer which utilizes laser interferometry as the basis for the length measurement system. The dilatometer is being designed for operation from ambient to 800 exp 0 C using samples which require mini...
W. D. Drotning
A high precision straw tube chamber with cathode readout
The high precision straw chamber with cathode readout was constructed and investigated. The 10 mm diameter straws were made of aluminized Mylar with transparent longitudinal window. The X-coordinate information has been taken from cathode strips as induced charges and investigated with the centroid method. The spatial resolution sigmax = 103 mum was obtained at a signal-to-noise ratio of about 70.
V. N. Bychkov; I. A. Golutvin; Yu. V. Ershov; E. V. Zubarev; A. B. Ivanov; V. N. Lysiakov; A. V. Makhankov; S. A. Movchan; V. D. Peshekhonov; T. Preda
A High-Precision NDIR Gas Sensor for Automotive Applications
A new high-precision spectroscopic gas sensor measuring carbon dioxide (CO2) for harsh environmental conditions of automotive applications is presented. The carbon dioxide concentration is the primary parameter for sensing in cabin air quality, as well as an important safety parameter when R744 (carbon dioxide) is used as the refrigerant in the air conditioning system. The automotive environment challenges the potential
Robert Frodl; Thomas Tille
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
VIEW OF MICRO-MACHINING, HIGH PRECISION EQUIPMENT USED TO CUSTOM MAKE SMALL PARTS. LUMPS OF CLAY; SHOWN IN THE PHOTOGRAPH, WERE USED TO STABILIZE PARTS BEING MACHINED. (11/1/87) - Rocky Flats Plant, Stainless Steel & Non-Nuclear Components Manufacturing, Southeast corner of intersection of Cottonwood & Third Avenues, Golden, Jefferson County, CO
Magnetic levitated high precision positioning system based on antagonistic mechanism
A six degree-of-freedom magnetically levitated high precision micro positioning system is designed to get rid of the friction which is one of the important factors limiting the resolution and accuracy of positioning devices. Since magnetic levitation systems are inherently unstable, most of the emphasis is placed on a magnetic circuit design so as to increase the system dynamic stability. For
Kee-Bong Choi; Soo-Hyun Kim; Yoon Keun Kwak
Parity violation experiments require precision manipulation of helicity-correlated beam coordinates on target at the nm/nrad-level. Achieving this unprecedented level of control requires a detailed understanding of the particle optics and careful tuning of the beam transport to keep anomalies from compromising the design adiabatic damping. Such efforts are often hindered by machine configuration and instrumentation limitations at the low energy end. A technique has been developed at CEBAF including high precision measurements, Mathematica-based analysis for obtaining corrective solutions, and control hardware/software developments for realizing such level of control at energies up to 5 GeV.
Yu-Chiu Chao
Modeling of High Precision Neutron Nonelastic Cross Sections
A new method has been applied to the determination of neutron nonelastic cross sections for iron {sup 56}Fe and lead {sup 208}Pb for energies between 5 and 26 MeV. These data have estimated errors of only a few percent and do not suffer from the ambiguities encountered in earlier nonelastic data. We attempt to fit these high precision data using both a semiclassical single phase shift model (nuclear Ramsauer model) as well as a recent global optical model that well reproduces a wide body of neutron scattering observables. At the 5% uncertainty level, both models produce satisfactory fits. However, neither model gives satisfactory fits to these new precise data. We conclude that fitting precise data, i.e., data with errors of approximately 2% or less, may require a nuclear mass dependence of radii that reflects structure effects such as shell closures.
Dietrich, F S; Anderson, J D; Bauer, R W; Grimes, S M; McNabb, D P
High precision calibration for 2D optical standard
NASA Astrophysics Data System (ADS)
Photomask is a kind of 2-D optical standard with etched orthogonal coordinates made of a glass substrate chrominged or filmed with other metal. In order to solve the problems of measurement and traceability of ultra precision photomasks used in advanced manufacturing industry, 2-D photomask optical standard was calibrated in high precision laser two coordinate standard device. A high precision differential laser interferometer system was used for a length standard, a high magnification optical micro vision system was used for precision optical positioning feedback. In this paper, a image measurement model was purposed; A sampling window auto identification algorithm was designed. Grid stripe image could be identified and aimed at automatically by this algorithm. An edge detection method based on bidirection progressive scanning and 3-sigma rule for eliminating outliers in sampling window was found. Dirty point could be removed with effect. Edge detection error could be lowered. By this means, the measurement uncertainty of 2-D optical standard's ruling span was less than 0.3 micrometer (k=2).
Sun, Shuanghua; Gan, Xiaochuan; Xue, Zi; Ye, Xiaoyou; Wang, Heyan; Gao, Hongtang
Ion beam figuring (IBF) for high precision optics
NASA Astrophysics Data System (ADS)
Recently and upcoming optical applications depend more and more on the precision of the optical elements used. The last is especially driven by shorter wavelength, higher flux densities and imaging close to the diffraction limit. Therefore a dramatically increasing demand on high precision and high quality optical components in leading edge equipment as well as common devices and instruments is observed. So far a few methods have been introduced to provide an adequate manufacturing performance using mechanical grinding and polishing techniques. Up to now the very sophisticated ion beam figuring (IBF) has not been used for common optics. The reasons for this might be the perception of higher costs and less knowledge about the technique in the industry. Now an affordable ion beam figuring technique has been developed to address precision aspherical optics applications. This paper introduces ion beam figuring technology based on equipment which is widely used in semiconductor mass production for ultra precise film thickness trimming. Ion beam figuring works by raster-scanning a focused broad ion beam across an optical surface with variable velocity and dwell time in order to precisely and locally trim away surface contour errors. As a new and cost effective approach the ion beam figuring system used in this presentation applies a 3 axis movement system only (compared to expensive 5-axis movements in other applications). X-and y-axes are used for the areal scan, and the z-axis is used for focus adjustment due to the surface contour of the optical element. The system was intentionally designed without the 2 additional tilt axes for incident angle adjustment and cleverly reduces the complexity and size of the system. It is shown that curved spherical or aspherical surfaces can be corrected down to ?/50 or better by using the state of the art 3-axes trimming system. Even with high spatial frequency parts final processing qualities better than ?/10 are achieved.
Demmler, Marcel; Zeuner, Michael; Allenstein, Frank; Dunger, Thoralf; Nestler, Matthias; Kiontke, Sven
Laser processing system development of large area and high precision
NASA Astrophysics Data System (ADS)
As industry of PCB (Printed Circuit Board) and display growing, this industry requires an increasingly high-precision quality so current cutting process in industry is preferred laser machining than mechanical machining. Now, laser machining is used almost "step and repeat" method in large area, but this method has a problem such as cutting quality in the continuity of edge parts, cutting speed and low productivity. To solve these problems in large area, on-the-fly (stagescanner synchronized system) is gradually increasing. On-the-fly technology is able to process large area with high speed because of stage-scanner synchronized moving. We designed laser-based high precision system with on-the-fly. In this system, we used UV nano-second pulse laser, power controller and scanner with telecentric f-theta lens. The power controller is consisted of HWP(Half Wave Plate), thin film plate polarizer, photo diode, micro step motor and control board. Laser power is possible to monitor real-time and adjust precision power by using power controller. Using this machine, we tested cutting of large area coverlay and sheet type large area PCB by applying on-the-fly. As a result, our developed machine is possible to process large area without the problem of the continuity of edge parts and by high cutting speed than competitor about coverlay.
Park, Hyeongchan; Ryu, Kwanghyun; Hwang, Taesang
Flight Test Performance of a High Precision Navigation Doppler Lidar
NASA Technical Reports Server (NTRS)
A navigation Doppler Lidar (DL) was developed at NASA Langley Research Center (LaRC) for high precision velocity measurements from a lunar or planetary landing vehicle in support of the Autonomous Landing and Hazard Avoidance Technology (ALHAT) project. A unique feature of this DL is that it has the capability to provide a precision velocity vector which can be easily separated into horizontal and vertical velocity components and high accuracy line of sight (LOS) range measurements. This dual mode of operation can provide useful information, such as vehicle orientation relative to the direction of travel, and vehicle attitude relative to the sensor footprint on the ground. System performance was evaluated in a series of helicopter flight tests over the California desert. This paper provides a description of the DL system and presents results obtained from these flight tests.
Pierrottet, Diego; Amzajerdian, Farzin; Petway, Larry; Barnes, Bruce; Lockard, George
High-precision Acceleration Measurement Systems for Space Applications
The unique micro-gravity environment in space has brought high-precision accelerometer numerous space applications, like the measurements of micro-gravity, the Earth's gravity, gravity gradient, and the research on atmospheric drag, solar radiation pressure, the Earth's diffuse reflection, and so on. This paper describes two systems for micro-acceleration measurement, one of which has been used to monitor the micro-gravity level in low-orbit
Furong Tang; Datong Xue; Jungang Lei; Yufeng Cheng
High precision thick target PIXE analyses of carbonaceous meteorites
High precision proton-induced X-ray (PIXE) thick target spectra of carbonaceous meteorites have been deconvoluted using previously described programs. Even in cases of totally overlapping peaks excellent fits to spectra were obtained. Concentrations for 15 elements in the mass range 56-100, as well as Pb, agree well in most cases with previous literature values. The total concentration range studied was over
D. S. Burnett; D. S. Woolum; T. M. Benjamin; P. S. Z. Rogers; C. J. Duffy; C. Maggiore
Versatile high-precision multiple-pass reflectometer.
A confocal mirror assembly is used to measure radiant reflectances in excess of 0.99 with high precision. The mirrors can be either plano or curved with a few diopters of power, and the angle of incidence can vary from 5 degrees to 70 degrees . Multilayer dielectric reflectors consisting of alternate layers of tantalum pentoxide and silica were prepared by evaporation in a vacuum. A maximum reflectance of 0.9996 +/- 0.0002 was measured at 520 nm. PMID:20203897
Arnon, O; Baumeister, P
Dipole model analysis of high precision HERA data
NASA Astrophysics Data System (ADS)
We analyze, within a dipole model, the inclusive deep inelastic scattering cross section data, obtained from the combination of the measurements of the H1 and ZEUS experiments performed at the HERA collider. We show that these high precision data are very well described within the dipole model framework, which is complemented with valence quark structure functions. We discuss the properties of the gluon density obtained in this way.
Luszczak, A.; Kowalski, H.
High-precision magnetic levitation stage for photolithography
In this paper, we present a high-precision magnetic levitation (maglev) stage for photolithography in semiconductor manufacturing. This stage is the worldÆs first maglev stage that provides fine six-degree-of-freedom motion controls and realizes large (50 mm ū 50 mm) planar motions with only a single magnetically levitated moving part. The key element of this stage is a linear motor capable of
Won-jong Kim; David L. Trumper
High-precision DEM reconstruction based on airborne LiDAR point clouds
NASA Astrophysics Data System (ADS)
Airborne LiDAR point clouds have become important data sources for DEM generation recently; however the problem of low precision and low efficiency in DEM production still exists. This paper proposes a new technical scheme for high-precision DEM production based on airborne LiDAR point clouds systematically. Firstly, an elevation and density analysis method is applied to filter out outliers. Secondly, ground points are detected by an improved filter algorithm based on the hierarchical smoothing method. Finally, feature lines are extracted by the planar surface fitting and intersecting method, and a simple data structure of feature lines preserved DEM is proposed to achieve reconstructing high accuracy DEM, combing feature lines with ground points. Experimental results show that the proposed scheme is able to compensate for deficiencies of existing DEM reconstruction techniques and can meet the needs of high precision DEM production based on LiDAR data.
Xu, Jingzhong; Kou, Yuan; Wang, Jun
High-precision Acceleration Measurement Systems for Space Applications
NASA Astrophysics Data System (ADS)
The unique micro-gravity environment in space has brought high-precision accelerometer numerous space applications, like the measurements of micro-gravity, the Earth's gravity, gravity gradient, and the research on atmospheric drag, solar radiation pressure, the Earth's diffuse reflection, and so on. This paper describes two systems for micro-acceleration measurement, one of which has been used to monitor the micro-gravity level in low-orbit spacecrafts, and the other is being studied for future space application on the recovery of the Earth's gravity field. The details include: 1.CMAMS for space micro-gravitational acceleration measurement The Chinese Micro-gravitational Acceleration Measurement System (CMAMS) is the third generation system for space micro-gravity measurement. The sensor used in the CMAMS is a quartz accelerometer. With its outstanding technical characteristics, like wide measurement range, broad frequency band, high measurement precision, high timing precision, and many other useful functions, such as data statistic, frequency spectrum analysis, default order, external order, data record and quasi-real-time data transfer, CMAMS works very well in a recent low-orbit flight, and some interesting results have been obtained. 2.NIAMS for the fine determination of the Earth's gravity field The Non-Inertial Acceleration Measurement System (NIAMS) is being studied in China, which will be used, as one of the important instruments, for the measurement of the Earth's gravity field. The sensor that would be used in NIAMS is a high-precision electrostatically suspended accelerometer. With its superexcellent performance through optimal structural design and electrostatic servo control system, the electrostatic accelerometer will be well suited for space applications. The electrostatic force gives the possibility to generate very weak but accurate accelerations while the capacitive sensing offers a high position resolution with negligible back-action. Besides for the determination of the Earth's gravity field, the NIAMS can be used for the monitoring of the low-frequency micro-gravity environment. The precision objective of NIAMS is 1 ng/Hz1/2 within the frequency bandwidth from 10-4 to 10-1 Hz.
Tang, Furong; Xue, Datong; Lei, Jungang; Cheng, Yufeng
Automated high precision secondary pH measurements
NASA Astrophysics Data System (ADS)
A new setup for high precision, automated secondary pH measurements together with a reference measurement procedure has been developed and tested in interlaboratory comparisons using buffers pH 4.005, pH 7.000, and pH 10.012 at 25 ░C and 37 ░C. Using primary buffers as standards, a standard uncertainty in pH better than 0.005 can be reached. The central measuring device is a one piece, thermostatted cell of PFA (perfluoroalkoxy) with a built-in Hamilton« Single PoreÖ Glass electrode. Due to its flow-through principle this device allows pH measurements with low consumption of measurement solutions. The very hydrophobic and smooth PFA as construction material facilitates complete emptying of the cell. Furthermore, the tempering unit affords very precise temperature control and hence contributes to the low target uncertainty of the produced secondary buffer solutions. Use of a symmetric measurement sequence and the two point calibration was sufficient to reach high precision and accuracy.
Bastkowski, F.; Jakobsen, P. T.; Stefan, F.; Kristensen, H. B.; Jensen, H. D.; Kawiecki, R.; Wied, C. E.; Kauert, A.; Seidl, B.; Spitzer, P.; Eberhardt, R.; Adel, B.
Modular Gravitational Reference Sensor for High Precision Astronomical Space Missions
NASA Astrophysics Data System (ADS)
We review the progress in developing the Modular Gravitational Reference Sensor (modular GRS) [1], which was first proposed as a simplified core sensor for space gravitational wave detection missions. In a modular GRS, laser beam from the remote the sensor does not illuminate the proof mass directly. The internal measurement from housing to proof mass is separated from the external interferometry. A double side grating may further simplify the structure and may better preserve the measurement precision. We review the recent progress in developing modular GRS at Stanford. We have further studied optical sensing design that combines advantage of high precision interferometric measurement and robust optical shadow sensing scheme. We have made critical progress in optical measurement of the center of mass position of a spherical proof mass at a precision without costing the dynamic range while spinning. We have successfully demonstrated the feasibility of fabricating localized grating pattern onto the dielectric and gold materials. We have conducted an initial experiment of rf heterodyne of cavity reflection and thus lowered optical power than that in the direct detection. We have further studied UV LED that will be used for AC charge management experiment. The modular GRS will be an in-time, cost effective product for the advanced Laser Interferometric Space Antenna (LISA) and the Big Bang Observatory (BBO). [1] K. Sun, G. Allen, S. Buchman, D. DeBra, and R. L. Byer, ōAdvanced Architecture for High Precision Space Laser Interferometersö, 5th International LISA Symposium, ESTEC, Noordwijk, The Netherlands, 12-16 July 2004. Class. Quantum Grav. 22 (2005) S287-S296.
Sun, Ke-Xun; Allen, G.; Buchman, S.; Byer, R. L.; Conklin, J. W.; DeBra, D. B.; Gill, D.; Goh, A.; Higuchi, S.; Lu, P.; Robertson, N.; Swank, A.
High Precision Polarimetry of the Epsilon Aurigae Eclipse
NASA Astrophysics Data System (ADS)
Polarimetry of the epsilon Aurigae eclipse has the potential to discern the stellar latitude occulted by the companion's dusty disk, which may directly test interferometric results. In addition, the limb polarization of the primary star may be measured, which is an effect predicted by S. Chandrasekhar and verified by spatially resolved observations of the Sun. I will present B band, polarimetric observations of epsilon Aurigae taken over six nights in September and October 2009 using the POLISH high precision polarimeter at the Lick 3-m telescope. Polarimetric precision achieved during each night is of order 1 part in 10^5. Extensive post-eclipse observations have been taken with the significantly upgraded POLISH2 polarimeter at Lick Observatory. This instrument simultaneously measures all four Stokes parameters (I, Q, U, and V) and achieves precision within 2.0 times the photon shot noise limit over an entire observing run. This work is supported by a NExScI Sagan Fellowship, UC Lab Fees Research Grant, and UCO/Lick Observatory.
Wiktorowicz, Sloane
High-Precision Floating-Point Arithmetic in ScientificComputation
At the present time, IEEE 64-bit floating-point arithmetic is sufficiently accurate for most scientific applications. However, for a rapidly growing body of important scientific computing applications, a higher level of numeric precision is required: some of these applications require roughly twice this level; others require four times; while still others require hundreds or more digits to obtain numerically meaningful results. Such calculations have been facilitated by new high-precision software packages that include high-level language translation modules to minimize the conversion effort. These activities have yielded a number of interesting new scientific results in fields as diverse as quantum theory, climate modeling and experimental mathematics, a few of which are described in this article. Such developments suggest that in the future, the numeric precision used for a scientific computation may be as important to the program design as are the algorithms and data structures.
Bailey, David H.
Molecular calipers for highly precise and accurate measurements of single-protein mechanics.
Single-molecule atomic force spectroscopy (AFM) has evolved into a powerful technique toward elucidating conformational changes in proteins when exposed to applied force. AFM technologies that are currently available allow for precise measurements of proteins length changes during conformational transitions. However, because of systematic errors in piezo calibration as well as errors originating from fitting experimental data using a worm-like chain model of polymer elasticity, high-precision measurements of length changes do not necessarily translate into highly accurate measurements of length changes, resulting in uncertainty in obtaining structural information about protein conformational changes. Actually achieving highly precise and accurate force spectroscopy measurements remains a challenge. Here, we report a protein caliper method that eliminates systematic errors that occur during single-protein force spectroscopy measurements, and thus achieves highly precise and accurate length change measurements in protein mechanics studies. To do this, a series of loop elongation variants of the small protein GB1, which differ by 2, 5, 10, 15, and 24 amino acid residues, were engineered. Differential measurements of amino acid residue length obtained from different AFM setups result in a precise measure of the length of a single amino acid residue, which varies within different AFM setups because of systematic error between individual AFM piezoelectric calibrations. The measured length of a single amino acid residue from a given AFM setup is then used as a caliper for the given setup to eliminate systematic error, leading to highly accurate and precise measurements of the number of amino acid residues that are involved in a conformation change of a polypeptide chain. We further developed a more precise, robust, and model-free method to determine the apparent size of single amino acid residues and conformational changes of proteins. This method improves the accuracy of single protein force spectroscopy measurements, providing an accurate means of measuring force-induced protein conformational changes. PMID:24555779
Wang, Yanyan; Hu, Xiaodong; Bu, Tianjia; Hu, Chunguang; Hu, Xiaotang; Li, Hongbin
[Technique progress of high-precision gas absorption spectroscopy with femtosecond optical frequency comb].
Femtosecond optical frequency comb, with large spectral range, narrow pulse width, high stability of frequency and many other remarkable properties, has a significant impact on optical frequency metrology, absolute distance measurement and high-precision spectroscopy. The time-domain and frequency-domain properties of femtosecond optical frequency comb is traced back to the microwave frequency standard, making it possible to open up the door to high-precision gas absorption spectrum detection. Femtosecond optical frequency comb spectroscopy has some excellent performances, such as fast measurement, high sensitivity, high resolution, high signal-to-noise ratio and so on. Therefore, more investments on femtosecond optical frequency comb spectroscopy will better make contribution to the environmental protection, industrial production, biological medicine, scientific research and other social fields. High-precision gas absorption spectroscopy with femtosecond optical frequency comb mainly includes frequency comb based cavity ring-down spectroscopy, cavity-enhanced frequency comb spectroscopy and dual-comb multi-heterodyne spectroscopy. Among them, according to the data collection, cavity-enhanced frequency comb spectroscopy can be divided into comb vernier method, virtually imaged phased array method and Fourier transform method. At present, related research has been widely carried out abroad, and domestic research is still in its infancy. This review summarizes main techniques in the high-precision gas absorption spectrum detection based on optical frequency comb, and demonstrates typical experimental schemes for different methods. It also analyzes the advantages and disadvantages of each method, and tracks frontier achievements of main research groups. PMID:24822396
Yang, Hong-Lei; Wei, Hao-Yun; Li, Yan; Ren, Li-Bing; Zhang, Hong-Yuan
High-Precision Timing of Several Millisecond Pulsars
NASA Astrophysics Data System (ADS)
The highest precision pulsar timing is achieved by reproducing as accurately as possible the pulse profile as emitted by the pulsar, in high signal-to-noise observations. The best profile reconstruction can be accomplished with several-bit voltage sampling and coherent removal of the dispersion suffered by pulsar signals as they traverse the interstellar medium. The Arecibo Signal Processor (ASP) and its counterpart the Green Bank Astronomical Signal Processor (GASP) are flexible, state-of-the-art wide-bandwidth observing systems, built primarily for high-precision long-term timing of millisecond and binary pulsars. ASP and GASP are in use at the 300-m Arecibo telescope in Puerto Rico and the 100-m Green Bank Telescope in Green Bank, West Virginia, respectively, taking advantage of the enormous sensitivities of these telescopes. These instruments result in high-precision science through 4 and 8-bit sampling and perform coherent dedispersion on the incoming data stream in real or near-real time. This is done using a network of personal computers, over an observing bandwidth of 64 to 128 MHz, in each of two polarizations. We present preliminary results of timing and polarimetric observations with ASP/GASP for several pulsars, including the recently-discovered relativistic double-pulsar binary J0737-3039. These data are compared to simultaneous observations with other pulsar instruments, such as the new "spigot card" spectrometer on the GBT and the Princeton Mark IV instrument at Arecibo, the precursor timing system to ASP. We also briefly discuss several upcoming observations with ASP/GASP.
Ferdman, R. D.; Stairs, I. H.; Backer, D. C.; Ramachandran, R.; Demorest, P.; Nice, D. J.; Lyne, A. G.; Kramer, M.; Lorimer, D.; McLaughlin, M.; Manchester, D.; Camilo, F.; D'Amico, N.; Possenti, A.; Burgay, M.; Joshi, B. C.; Freire, P. C.
Test results of high-precision large cryogenic lens holders
NASA Astrophysics Data System (ADS)
For the Euclid mission a Pre-Development phase is implemented to prove feasibility of individual components of the system [1]. The Near Infrared Spectrometer and Photometer (NISP) of EUCLID requires high precision large lens holders (?170 mm) at cryogenic temperatures (150K). The four lenses of the optical system are made of different materials: fused silica, CaF2, and LF5G15 that are mounted in a separate lens barrel design. Each lens has its separate mechanical interface to the lens barrel, the so called adaption ring. The performance of the lens holder design is verified by adapted test equipment and test facility including an optical metrology system. The characterization of the lens deformation and displacement (decenter, tilt) due to mechanical loads of the holder itself as well as thermally induced loads are driven by the required submicron precision range and the operational thermal condition. The surface deformation of the lens and its holder is verified by interferometric measurements, while tilt and position accuracy are measured by in-situ fibre based distance sensors. The selected distance measurement sensors have the capability to measure in a few mm range with submicron resolution in ultra high vacuum, in vibration environments and at liquid nitrogen temperatures and below. The calibration of the measurement system is of crucial importance: impacts such as temperature fluctuation, surface roughness, surface reflectivity, straylight effects, etc. on the measured distance are carefully calibrated. Inbuilt thermal expansion effects of the fibre sensors are characterized and proven with lens dummy with quasi zero CTE. The paper presents the test results and measured performance of the high precision large cryogenic lens holders attained by the metrology system. These results are presented on behalf of the EUCLID consortium.
Gal, C.; Reutlinger, A.; Boesz, A.; Leberle, T.; Mottaghibonab, A.; Eckert, P.; Dubowy, M.; Gebler, H.; Grupp, F.; Geis, N.; Bode, A.; Katterloher, R.; Bender, R.
High-Precision Motorcycle Trajectory Measurements Using GPS
NASA Astrophysics Data System (ADS)
A method for measuring motorcycle trajectory using GPS is needed for simulating motorcycle dynamics. In GPS measurements of a motorcycle, both the declination of the motorcycle and obstacles near the course can cause problems. Therefore, we propose a new algorithm for GPS measurement of motorcycle trajectory. We interpolate the missing observation data within a few seconds using polynomial curves, and use a Kalman filter to smoothen position calculations. This results in obtaining trajectory with high accuracy and with sufficient continuity. The precision is equal to that of fixed point positioning, given a sufficient number of available satellites.
Koyama, Yuichiro; Tanaka, Toshiyuki
An S-band radiometer design with high absolute precision
NASA Technical Reports Server (NTRS)
A radiometer for the remote measurement of sea surface temperature is described. The development of an instrument capable not only of high relative accuracy (i.e., resolution) but also of high absolute precision is considered. The concepts underlying the design of an instrument capable of an absolute accuracy of a few tenths degrees Kelvin in the measurement of brightness temperature at S band are described. The role of the antenna is discussed, and the importance of high ohmic and beam efficiencies is stressed. The hardware itself is fully described, along with an outline concerning the design of a unique cryogenically cooled termination used to calibrate the whole radiometer, including antenna. Finally, some test results are presented that show that the design goals for the instrument have been closely approached.
Hardy, W. N.; Gray, K. W.; Love, A. W.
Experimental study on the precise orbit determination of the BeiDou navigation satellite system.
The regional service of the Chinese BeiDou satellite navigation system is now in operation with a constellation including five Geostationary Earth Orbit satellites (GEO), five Inclined Geosynchronous Orbit (IGSO) satellites and four Medium Earth Orbit (MEO) satellites. Besides the standard positioning service with positioning accuracy of about 10 m, both precise relative positioning and precise point positioning are already demonstrated. As is well known, precise orbit and clock determination is essential in enhancing precise positioning services. To improve the satellite orbits of the BeiDou regional system, we concentrate on the impact of the tracking geometry and the involvement of MEOs, and on the effect of integer ambiguity resolution as well. About seven weeks of data collected at the BeiDou Experimental Test Service (BETS) network is employed in this experimental study. Several tracking scenarios are defined, various processing schemata are designed and carried out; and then, the estimates are compared and analyzed in detail. The results show that GEO orbits, especially the along-track component, can be significantly improved by extending the tracking network in China along longitude direction, whereas IGSOs gain more improvement if the tracking network extends in latitude. The involvement of MEOs and ambiguity-fixing also make the orbits better. PMID:23529116
He, Lina; Ge, Maorong; Wang, Jiexian; Wickert, Jens; Schuh, Harald
High-precision continuous-flow isotope ratio mass spectrometry.
Although high-precision isotope determinations are routine in many areas of natural science, the instrument principles for their measurements have remained remarkably unchanged for four decades. The introduction of continuous-flow techniques to isotope ratio mass spectrometry (IRMS) instrumentation has precipitated a rapid expansion in capabilities for high-precision measurement of C, N, O, S, and H isotopes in the 1990s. Elemental analyzers, based on the flash combustion of solid organic samples, are interfaced to IRMS to facilitate routine C and N isotopic analysis of unprocessed samples. Gas/liquid equilibrators have automated O and H isotopic analysis of water in untreated aqueous fluids as complex as urine. Automated cryogenic concentrators permit analysis at part-per-million concentrations in environmental samples. Capillary gas chromatography interfaced to IRMS via on-line microchemistry facilitates compound-specific isotope analysis (CSIA) for purified organic analytes of 1 nmol of C, N, or O. GC-based CSIA for hydrogen and liquid chromatography-based interfaces to IRMS have both been demonstrated, and continuing progress promises to bring these advances to routine use. Automated position-specific isotope analysis (PSIA) using noncatalytic pyrolysis has been shown to produce fragments without appreciable carbon scrambling or major isotopic fractionation, and shows great promise for intramolecular isotope ratio analysis. Finally, IRMS notation and useful elementary isotopic relationships derived from the fundamental mass balance equation are presented. PMID:9538528
Brenna, J T; Corso, T N; Tobias, H J; Caimi, R J
High Precision Signal Processing Algorithm for White Light Interferometry
A new signal processing algorithm for absolute temperature measurement using white light interferometry has been proposed and investigated theoretically. The proposed algorithm determines the phase delay of an interferometer with very high precision (? one fringe) by identifying the zero order fringe peak of cross-correlation of two fringe scans of white light interferometer. The algorithm features cross-correlation of interferometer fringe scans, hypothesis testing and fine tuning. The hypothesis test looks for a zero order fringe peak candidate about which the cross-correlation is symmetric minimizing the uncertainty of mis-identification. Fine tuning provides the proposed algorithm with high precision sub-sample resolution phase delay estimation capability. The shot noise limited performance of the proposed algorithm has been analyzed using computer simulations. Root-mean-square (RMS) phase error of the estimated zero order fringe peak has been calculated for the changes of three different parameters (SNR, fringe scan sample rate, coherence length of light source). Computer simulations showed that the proposed signal processing algorithm identified the zero order fringe peak with a miss rate of 3 ū 10-4 at 31 dB SNR and the extrapolated miss rate at 35 dB was 3 ū 10-8. Also, at 35 dB SNR, RMS phase error less than 10-3 fringe was obtained. The proposed signal processing algorithm uses a software approach that is potentially inexpensive, simple and fast.
Kim, Jeonggon Harrison
High-precision wavefront sensor for the SUNRISE Telescope
NASA Astrophysics Data System (ADS)
SUNRISE is a 1m solar telescope for the visible and near UV wavelength range. It will be flown in long duration stratospheric balloon flights in Antarctica, with a first scientific flight in 2007. In this paper, we describe the development of a wave-front sensing system that will be used for the automatic in-flight alignment of the SUNRISE telescope and for high-precision tracking. The system is based on the principles of an adaptive optics system. A 19-element wavefront sensor is used to determine low order aberrations of the telescope, including defocus and spherical aberrations. The correction is achieved by controlling the position of the telescope secondary and a focusing mirror in closed-loop. In addition to these quasi-static aberrations, the system will also measure image motion with a dynamical range of at least 30 Hz and with a precision of about 0.005 arcs. To this end, the image displacement measured in all sub-apertures is averaged and used as tip-tilt correction signal. This signal will feed a second closed-loop system that drives the tip-tilt mirror assembly. The tip-tilt mirror unit is designed as a dual-stage system that consists of a slow component with a large range of 60 arcs and a fast component with high bandwidth.
Schmidt, Wolfgang; Berkefeld, Thomas; Friedlein, Ruediger; Heidecke, Frank; Kentischer, Thomas; von der L³he, Oskar F.; Sigwarth, Michael; Soltau, Dirk; Walde, E.
Selection and use of TLDS for high precision NERVA shielding measurements
NASA Technical Reports Server (NTRS)
An experimental evaluation of thermoluminescent dosimeters was performed in order to select high precision dosimeters for a study whose purpose is to measure gamma streaming through the coolant passages of a simulated flight type internal NERVA reactor shield. Based on this study, the CaF2 chip TLDs are the most reproducible dosimeters with reproducibility generally within a few percent, but none of the TLDs tested met the reproducibility criterion of plus or minus 2%.
Woodsum, H. C.
High precision depolarisation measurements with an opaque test bench
NASA Astrophysics Data System (ADS)
We present a tool to investigate neutron depolarisation effects with 10-4 precision. The test bench consists of two opaque 3He cells with in-situ adiabatic fast passage flipping of the helium spin. The cells polarise a neutron beam to more than 99.99 % and analyse its polarisation with high accuracy. For depolarisation studies, a sample can be inserted between the two cells and its effect on a primarily highly polarised beam is analysed. The test bench has been validated at the cold neutron beam PF1B at Institut Laue-Langevin, France. We present here preliminary results for the wavelength range from 5┼ to 7┼. Polarisation with super mirrors is limited to about 99.7%. Direct evidence of depolarisation in the order of 10-3 in polarising super mirrors was found by the test bench.
Klauser, C.; Chastagnier, J.; Jullien, D.; Petoukhov, A.; Soldner, T.
High-precision Mg isotopic systematics of bulk chondrites
NASA Astrophysics Data System (ADS)
Variations of the mass-independent abundance of 26Mg ( ?26Mg*) and stable Mg ( ?25Mg) isotope composition of chondrites are important because they constrain the homogeneity of 26Al and Mg isotopes in the proto-planetary disc and the validity of the short-lived 26Al-to- 26Mg chronometer applied to meteorites. We present high-precision Mg isotope data and Al/Mg ratios of chondrites representing nearly all major chondrite classes, including a step-leaching experiment on the CM2 chondrite Murchison. ?26Mg* variations in leachates of Murchison representing acid soluble material are ? 30 times smaller than reported for neutron-rich isotopes of Ti and Cr and do not reveal resolvable deficits in ?26Mg* (-0.002 to + 0.118ē). Very small variations in ?26Mg* anomalies in bulk chondrites (-0.006 to + 0.019ē) correlate with increasing 27Al/ 24Mg ratios and ?50Ti, reflecting the variable presence of calcium-aluminium-rich inclusions (CAIs) in some types of carbonaceous chondrites. Similarly, release of radiogenic 26Mg produced by 26Al decay from CAI material in the step-leaching of Murchison best explains the high ?26Mg* observed in the last, aggressive, leaching steps of this experiment. Overall, the observed variations in ?26Mg* are small and potential differences beyond that which result from the presence of CAI-like material cannot be detected within the analytical uncertainties of this study (▒ 0.004ē). The results do not allow radical heterogeneity of 26Al (?▒30%) or measurable Mg nucleosynthetic heterogeneity (?▒0.005ē) to have existed on a planetesimal scale in the proto-planetary disc. Combined with published ?26Mg* data for CAIs, the bulk chondrite data yield a precise initial ( 26Al/ 27Al) 0 = (5.21 ▒ 0.06) ū 10 -5 and ?26Mg* = -0.0340 ▒ 0.0016ē for the Solar System. However, it is not possible with the currently available data to determine with certainty whether CAIs and the material from which planetesimals accreted including chondrite parent bodies had precisely the same initial levels of 26Al, although planetesimals and planets appear to have accreted from material with a mean initial ( 26Al/ 27Al) 0 in the range of 2.1 to 6.7 ū 10 - 5 . The average stable Mg isotope composition of all analysed chondrites, with the exception of a chondrule from the CBa chondrite Gujba ( ?25Mg DSM-3 = -0.032 ▒ 0.035ē), is ?25Mg DSM-3 = -0.152 ▒ 0.079ē (2 sd) and is indistinguishable from that of the Earth's mantle.
Schiller, Martin; Handler, Monica R.; Baker, Joel A.
Describing Oscillations of High Energy Neutrinos in Matter Precisely
We present a formalism for precise description of oscillation phenomena in matter at high energies or high densities, V>{delta}m{sup 2}/2E, where V is the matter-induced potential of neutrinos. The accuracy of the approximation is determined by the quantity sin{sup 2}2{theta}{sub m}{delta}V/2{pi}V, where {theta}{sub m} is the mixing angle in matter and {delta}V is a typical change of the potential over the oscillation length (l{approx}2{pi}/V). We derive simple and physically transparent formulas for the oscillation probabilities, which are valid for arbitrary matter density profiles. They can be applied to oscillations of high-energy (E>10 GeV) accelerator, atmospheric, and cosmic neutrinos in the matter of the Earth, substantially simplifying numerical calculations and providing an insight into the physics of neutrino oscillations in matter. The effect of parametric enhancement of the oscillations of high-energy neutrinos is considered.
Akhmedov, E.Kh. [Physik Department T30, Technische Universitaet Muenchen, James-Franck Strasse, D-85748 Garching (Germany); Kurchatov Institute, Moscow (Russian Federation); Maltoni, M. [C.N. Yang Institute for Theoretical Physics, SUNY at Stony Brook, Stony Brook, New York 11794-3840 (United States); Smirnov, A.Yu. [ICTP, Strada Costiera 11, 34014 Trieste (Italy); INR, Russian Academy of Sciences, Moscow (Russian Federation)
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 128ū128-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 1ū1-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.
Precision, high dose radiotherapy: helium ion treatment of uveal melanoma.
We report on 75 patients with uveal melanoma who were treated by placing the Bragg peak of a helium ion beam over the tumor volume. The technique localizes the high dose region very tightly around the tumor volume. This allows critical structures, such as the optic disc and the macula, to be excluded from the high dose region as long as they are 3 to 4 mm away from the edge of the tumor. Careful attention to tumor localization, treatment planning, patient immobilization and treatment verification is required. With a mean follow-up of 22 months (3 to 60 months) we have had only five patients with a local recurrence, all of whom were salvaged with another treatment. Pretreatment visual acuity has generally been preserved as long as the tumor edge is at least 4 mm away from the macula and optic disc. The only serious complication to date has been an 18% incidence of neovascular glaucoma in the patients treated at our highest dose level. Clinical results and details of the technique are presented to illustrate potential clinical precision in administering high dose radiotherapy with charged particles such as helium ions or protons. PMID:2579050
Saunders, W M; Char, D H; Quivey, J M; Castro, J R; Chen, G T; Collier, J M; Cartigny, A; Blakely, E A; Lyman, J T; Zink, S R
Highly precise and robust packaging of optical components
NASA Astrophysics Data System (ADS)
In this paper we present the development of a compact, thermo-optically stable and vibration and mechanical shock resistant mounting technique by soldering of optical components. Based on this technique a new generation of laser sources for aerospace applications is designed. In these laser systems solder technique replaces the glued and bolted connections between optical component, mount and base plate. Alignment precision in the arc second range and realization of long term stability of every single part in the laser system is the main challenge. At the Fraunhofer Institute for Laser Technology ILT a soldering and mounting technique has been developed for high precision packaging. The specified environmental boundary conditions (e.g. a temperature range of -40 ░C to +50 ░C) and the required degrees of freedom for the alignment of the components have been taken into account for this technique. In general the advantage of soldering compared to gluing is that there is no outgassing. In addition no flux is needed in our special process. The joining process allows multiple alignments by remelting the solder. The alignment is done in the liquid phase of the solder by a 6 axis manipulator with a step width in the nm range and a tilt in the arc second range. In a next step the optical components have to pass the environmental tests. The total misalignment of the component to its adapter after the thermal cycle tests is less than 10 arc seconds. The mechanical stability tests regarding shear, vibration and shock behavior are well within the requirements.
Leers, Michael; Winzen, Matthias; Liermann, Erik; Faidel, Heinrich; Westphalen, Thomas; Miesner, J÷rn; Luttmann, J÷rg; Hoffmann, Dieter
High-precision Ice Surface Topography Mapping Using Radar Interferometry
NASA Astrophysics Data System (ADS)
In May 2009 a new radar technique for mapping ice surface topography was demonstrated in a Greenland campaign as part of the NASA International Polar Year activities. This was achieved with the airborne Glacier and Ice Surface Topography Interferometer (GLISTIN-A): a 35.6 GHz single-pass interferometer. Although the technique of using radar interferometry for mapping terrain has been demonstrated before, this is the first such application at millimeter-wave frequencies. Instrument performance indicates swath widths over the ice between 5-7km, with height precisions ranging from 30cm-3m at a posting of 3m x 3m. However, for this application the electromagnetic wave will penetrate an unknown amount into the snow cover thus producing an effective bias that must be calibrated. To evaluate this, GLISTIN-A flew a coordinated collection with the NASA Wallops Airborne Topographic Mapper (ATM) on a transect from GreenlandÆs Summit to its West coast. Two field calibration sites were established at Colorado Institute for Research in Environmental ScienceÆs Swiss Camp and the National Science FoundationÆs Summit station. Additional collections entailed flying a mosaic over Jakobshavn glacier which was repeated after 6 days to reveal surface dynamics. Through detailed calibration and inter-sensor comparisons we were able to observe penetration biases and compare them with theoretical expectations. We also demonstrated GLISTIN-AÆs capability to measure the topography of large glacier systems in a seamless fashion and accurately measuring volume changes with a high level of spatial detail. In particular, repeating the airborne campaigns to observe elevation changes over time will allow very accurate volume change measurements. Not only is this very important for mass balance studies to have a precise mass-loss estimate, but the spatial pattern can reveal ice dynamics effects and surface mass balance effects. In this manner a high resolution, high-precision topographic mapping capability is an ideal complement to the ICESat, ICESat II and Cryosat altimeters. Interpolating between the high-accuracy elevation profiles from altimeters such as the ATM or ICESat II with the high-resolution GLISTIN-A swath will enable detailed ice-surface topography maps and extended spatial coverage. The result is the potential for higher fidelity mass-balance estimates and improved observational coverage. Upgrades are currently underway to improve the performance and portability of GLISTIN-A such that, onboard a long-range aircraft this radar can map GreenlandÆs significant glaciers in a few days. The upgraded GLISTIN-A will be compatible with GlobalHawk installation making, Antarctica basin and coastal mapping feasible. GLISTIN will make more topographic products available to glaciologists, initially through dedicated airborne campaigns or ultimately, perhaps, as a satellite mission.
Moller, D.; Hensley, S.; Michel, T.; Rignot, E. J.; Simard, M.; Krabill, W. B.; Sonntag, J. G.
A simple high-precision Jacob's staff design for the high-resolution stratigrapher
The new generation of high-resolution stratigraphic research depends upon detailed bed-by-bed analysis to enhance regional correlation potential. The standard Jacob's staff is not an efficient and precise tool for measuring thin-bedded strata. The high-precision Jacob's staff design presented and illustrated in this paper meets the qualifications required of such an instrument. The prototype of this simple design consists of a sliding bracket that holds a Brunton-type compass at right angles to a ruled-off staff. This instrument provides rapid and accurate measurement of both thick- or thin-bedded sequences, thus decreasing field time and increasing stratigraphic precision. -Author
Elder, W. P.
A Computer Controlled Precision High Pressure Measuring System
NASA Astrophysics Data System (ADS)
A microcontroller (AT89C51) based electronics has been designed and developed for high precision calibrator based on Digiquartz pressure transducer (DQPT) for the measurement of high hydrostatic pressure up to 275 MPa. The input signal from DQPT is converted into a square wave form and multiplied through frequency multiplier circuit over 10 times to input frequency. This input frequency is multiplied by a factor of ten using phased lock loop. Octal buffer is used to store the calculated frequency, which in turn is fed to microcontroller AT89C51 interfaced with a liquid crystal display for the display of frequency as well as corresponding pressure in user friendly units. The electronics developed is interfaced with a computer using RS232 for automatic data acquisition, computation and storage. The data is acquired by programming in Visual Basic 6.0. This system is interfaced with the PC to make it a computer controlled system. The system is capable of measuring the frequency up to 4 MHz with a resolution of 0.01 Hz and the pressure up to 275 MPa with a resolution of 0.001 MPa within measurement uncertainty of 0.025%. The details on the hardware of the pressure measuring system, associated electronics, software and calibration are discussed in this paper.
Sadana, S.; Yadav, S.; Jha, N.; Gupta, V. K.; Agarwal, R.; Bandyopadhyay, A. K.; Saxena, T. K.
High-precision heliostat for long-path light tracking
NASA Astrophysics Data System (ADS)
A heliostat has been designed and built for use in optical remote sensing of the atmosphere. The heliostat uses two flat mirrors to track the sun and direct the sunlight to optical instruments. A stepper motor driven horizontal turntable is used to track the sun in azimuth and support an elevation assembly and a mechanical tower. The stepper motor driven elevation assembly drives an acquisition mirror that tracks the sun in elevation. This mirror directs the solar beam to a secondary mirror fixed on the mechanical tower. The secondary mirror then directs the solar beam along the axis of the tracker for use in measurements. A sensitive, high resolution CCD camera, receives a small part of the solar beam to analyze for fine servo-control. Ground based tests have demonstrated this instrument"s tracking capability for the sun, the moon, stars and for long pathlength sources. Presently, this system is coupled with a high-resolution Brucker 120M spectrometer used to obtain solar absorption spectra. The heliostat directs the solar radiation along the spectrometer optical axis. The pointing precision was measured to be better than 0.5 arcsec. A description of the heliostat is presented, as well as the results of ground tests.
Hawat, Tom; Stephen, Thomas M.; DeMaziere, Martine M.; Neefs, Eddy
High precision metrology based microwave effective linewidth measurement technique.
A precision microwave effective linewidth measurement technique for magnetic samples has been developed. The measurement utilizes a high-Q cylindrical cavity that contains the sample of interest, a highly stable and programable static magnetic field source, a computer controlled network analyzer for cavity center frequency omega c and quality factor Qc determinations, and the standard metrological substitution ABA method for accurate relative omega c and Qc measurements. Sequential long term ABA measurements show that the time and temperature drifts and random errors are the dominant sources of error, with uncertainties in omega c/2pi and Qc in the range of 50 kHz and 25, respectively. The ABA method is applied to eliminate these drifts and minimize the random errors. For measurements over 25 ABA cycles, accuracy is improved to 0.14 kHz for omega c/2pi and 3 for Qc. The temperature variation over a single ABA cycle is generally on the order of 10(-3)-10(-5) degrees C and there is no need for any further temperature stabilization or correction measures. The overall uncertainty in the 10 GHz effective linewidth determinations for a 3 mm diam, 0.5 mm thick polycrystalline yttrium iron garnet (YIG) disk is 0.15 Oe or less, well below the intrinsic single crystal YIG linewidth. This represents a factor of 10 improvement in measurement accuracy over previous work. PMID:18052484
Mo, Nan; Green, Jerome J; Beitscher, Bailey A; Patton, Carl E
A semiautomatic image analyzer for cell counts in monolayers. I. Construction, experimental procedure, and precision obtained.
A simple, flexible, low-cost image analyzer system is presented for determination of the total number of cells and the number of viable cells in monolayers of nonconfluent cells. Viable cells were identified and counted using an immunofluorescence method using fluorescein diacetate. Alveolar macrophages from rabbits were used. The different possible counting procedures that could be performed are analyzed. The precision of the method of estimating the cell numbers is indicated by a coefficient of variation of 5%. The experimental procedure is given for a short-term toxicological in vitro test in which the semiautomatic counting procedures can be performed within 1.5 h. PMID:2760937
Thorķn, S A; Lanke, J
High precision object geo-localization and visualization in sensor networks
NASA Astrophysics Data System (ADS)
The wide availability of previously acquired, geo-referenced imagery enables automatic video based solutions for high precision object geo-localization and cooperative visualization. We present a system which geo-references objects seen in UAV video streams, distributes this information in a sensor network and visualizes them on modern smartphones using augmented reality techniques. The feasibility of the approach was experimentally validated using Mini-UAV ("MD-400") and high altitude UAV video footage in combination with modern off-the-shelve smartphones. Applications are widespread and include for instance crisis and disaster management or military applications.
Lemaire, Simon; Bodensteiner, Christoph; Arens, Michael
Closed loop high precision position control system with optical scale
NASA Astrophysics Data System (ADS)
With the developments of science of art, there are more and more demands on the high resolution control of position of object to be controlled, such as lathe, product line, elements in the optical resonant cavity, telescope, and so on. As one device with high resolution, the optical scale has more and more utility within the industrial and civil applications. With one optical scale and small DC servo motor, one closed loop high resolution position control system is constructed. This apparatus is used to control the position of the elements of optical system. The optical scale is attached on the object or reference guide way. The object position is sampled by a readhead of non-contact optical encoder. Control system processes the position information and control the position of object through the motion control of servo DC motor. The DC motor is controlled by one controller which is connected to an industrial computer. And the micro frictionless slide table does support the smooth motion of object to be controlled. The control algorithm of system is PID (Proportional-Integral-Differential) methods. The PID control methods have well ROBUST. The needed data to control are position, velocity and acceleration of the object. These three parameters correspond to the PID characters respectively. After the accomplishments of hardware, GUI (Graphical user interface), that is, the software of control system is also programmed. The whole system is assembled by specialized worker. Through calibration experiments, the coefficients of PID are obtained respectively. And then the precision of position control of the system is about 0.1?m.
Ge, Cheng-liang; Liao, Yuan; He, Zhong-wu; Luo, Zhong-xiang; Huang, Zhi-wei; Wan, Min; Hu, Xiao-yang; Fan, Guo-bin; Liang, Zheng
High precision optical finishing of lightweight silicon carbide aspheric mirror
NASA Astrophysics Data System (ADS)
Critical to the deployment of large surveillance optics into the space environment is the generation of high quality optics. Traditionally, aluminum, glass and beryllium have been used; however, silicon carbide becomes of increasing interest and availability due to its high strength. With the hardness of silicon carbide being similar to diamond, traditional polishing methods suffer from slow material removal rates, difficulty in achieving the desired figure and inherent risk of causing catastrophic damage to the lightweight structure. Rather than increasing structural capacity and mass of the substrate, our proprietary sub-aperture aspheric surface forming technology offers higher material removal rates (comparable to that of Zerodur or Fused Silica), a deterministic approach to achieving the desired figure while minimizing contact area and the resulting load on the optical structure. The technology performed on computer-controlled machines with motion control software providing precise and quick convergence of surface figure, as demonstrated by optically finishing lightweight silicon carbide aspheres. At the same time, it also offers the advantage of ideal pitch finish of low surface micro-roughness and low mid-spatial frequency error. This method provides a solution applicable to all common silicon carbide substrate materials, including substrates with CVD silicon carbide cladding, offered by major silicon carbide material suppliers. This paper discusses a demonstration mirror we polished using this novel technology. The mirror is a lightweight silicon carbide substrate with CVD silicon carbide cladding. It is a convex hyperbolic secondary mirror with 104mm diameter and approximately 20 microns aspheric departure from best-fit sphere. The mirror has been finished with surface irregularity of better than 1/50 wave RMS @632.8 nm and surface micro-roughness of under 2 angstroms RMS. The technology has the potential to be scaled up for manufacturing capabilities of large silicon carbide optics due to its high material removal rate.
Kong, John; Young, Kevin
[High-precision wavelength calibration of wide-band monochromator].
Usually the monochromator is used to output monochromatic light to calibrate the space remote sensing spectrometer. In the present paper, the confidence of space remote sensing spectrometer is used as a standard to evaluate the precision of wide-band monochromator wavelength calibration. Through analysis of the accuracy of the instrument, the monochromator wavelength repeatability error and deviations was obtained respectively. And the intrinsic spectrum of the high pressure mercury lamp and the grating diffraction was used as calibration lines to avoid the error caused by replacing the light source. Through the special method of wavelength calibration to shorten the scan time, the Gaussian fitting was used to look for peaks of wavelength to reduce error. Finally, the relationship derived from polynomial fitting to measure the exact wavelengths' accuracy of the monochromator and calculate the calibration confidence of the space remote sensing spectrometer. Using this method, we can make wavelength accuracy of the 1.5 M monochromator with wavelength band from 200 to 840 nm to reach to +/- 0.016 nm, then the confidence of the space remote sensing spectrometer can reach to 99.82%. PMID:23285905
Zhang, Zi-Hui; Wang, Shu-Rong; Huang, Yu; Li, Bo; Yu, Xiang-Yang; Lin, Guan-Yu
Interferometric apparatus for ultra-high precision displacement measurement
NASA Technical Reports Server (NTRS)
A high-precision heterodyne interferometer measures relative displacement by creating a thermally-insensitive system generally not subject to polarization leakage. By using first and second light beams separated by a small frequency difference (.DELTA.f), beams of light at the first frequency (f.sub.0) are reflected by co-axial mirrors, the first mirror of which has a central aperture through which the light is transmitted to and reflected by the second mirror. Prior to detection, the light beams from the two mirrors are combined with light of the second and slightly different frequency. The combined light beams are separated according to the light from the mirrors. The change in phase (.DELTA..phi.) with respect to the two signals is proportional to the change in distance of Fiducial B by a factor of wavelength (.lambda.) divided by 4.pi. (.DELTA.L=.lambda..DELTA..phi.1/(4.pi.)). In a second embodiment, a polarizing beam splitting system can be used.
Zhao, Feng (Inventor)
High Precision 40K/39K Ratio Determination
NASA Astrophysics Data System (ADS)
Potassium is one of the eight most abundant chemical elements in the Earth's crust and a major element in many rock-forming minerals. The isotope 40K is radioactive and undergoes ?- decay to 40Ca (ca. 89.3%) and electron capture to 40Ar (ca. 10.7%). Both decays can potentially be used as dating systems. The most commonly used branch is the decay of 40K to 40Ar because it can yield highly precise ages. Both decay schemes rely on the knowledge of the 40K branching ratio and the natural 40K abundance. A 40K abundance of 0.011672▒41 % was measured on terrestrial material [1]. The relative uncertainty of 0.35 % has not been improved since. Recent improvements in the precision of mass spectrometric measurements have led to the situation that the uncertainties on the K decay constant and the abundance of 40K are a major source of uncertainty on the measured ages. A more precise definition of the 40K decay constant was attempted by different research groups within the last decade [2-9] but the goal of obtaining 0.1 % relative uncertainty on K-Ar ages for geological materials, as requested by the EARTHtime initiative, has not been achieved yet. In order to improve on this situation we studied the abundances of the K isotopes in terrestrial standards. A ThermoFischer Triton+ thermal ionisation mass spectrometer was used for K isotope ratio measurements of the NIST SRM 918b K standard loaded on Ta filaments with 0.1M phosphoric acid. Three techniques were applied: (A) dynamic measurement with in-run normalisation to the IUPAC value 41K/39K=0.072168; (B) a simple total evaporation procedure; (C) the "NBL-modified" total evaporation [10]. The 40K ion beam was measured in a Faraday cup with a 1E12 ? resistor; 39K and 41K were collected in Faraday cups with 1E11 ? resistors. Amplifier gains were intercalibrated by supplying fixed voltages off-line. Different measurement techniques were combined with different loading procedures. We also tested ionisation yields for the evaporation procedures (B) and (C). Our measured 40K/39K ratios are statistically indistinguishable from those reported by [1] but have lower uncertainties. Techniques A, B and C gave 1 standard error of 0.07 %, 0.2 %, and 0.14 %, respectively. 1. Garner E.L. et al. (1975) J.Res.Natl.Bur.Stand.79A, 713-725. 2. Grau Malonda A., Grau Carles A. (2002) Appl. Radiat. Isot. 56, 153-156. 3. Kossert K., G³nter E. (2004) Appl.Radiat.Isot.60, 459-464. 4. Krumrei T.V. et al. (2006) Chem.Geol. 227, 258-273. 5. Kwon J. et al. (2002) Math.Geol. 34, 457-475. 6. Min K. et al. (2000) Geochim. Cosmochim. Acta 64, 73-98. 7. Nõgler T.F., Villa I.M. (2000) Chem. Geol. 169, 5-16. 8. Renne P.R. et al. (2010) Geochim. Cosmochim. Acta 74, 5349-5367. 9. Schwarz W.H. et al. (2011) Geochim. Cosmochim. Acta 75, 5094-5096. 10. Richter S., Goldberg S.A. (2003) Int. J. Mass Spect. 229, 181-197.
Naumenko, M. O.; Mezger, K.; Nagler, T. F.; Villa, I. M.
High precision differential photometry of planet transits with the MMTF
We propose to use Magellan+MMTF(IMACS) to achieve some of the very highest precision ground-based, time-differential, narrow-band photometry to date on selected favorable transiting planet host stars. The proposed observations are expected to provide precise measurements of the time, duration, shape, and color of an exoplanet transit. Our primary target, CoRoT-7, is an active star hosting the first transiting super-Earth transiting
Brian L. Lee; Knicole D. Colon; Eric B. Ford; Cullen H. Blake; Suvrath Mahadevan
High precision metrology based microwave effective linewidth measurement technique
A precision microwave effective linewidth measurement technique for magnetic samples has been developed. The measurement utilizes a high-Q cylindrical cavity that contains the sample of interest, a highly stable and programable static magnetic field source, a computer controlled network analyzer for cavity center frequency {omega}{sub c} and quality factor Q{sub c} determinations, and the standard metrological substitution ABA method for accurate relative {omega}{sub c} and Q{sub c} measurements. Sequential long term ABA measurements show that the time and temperature drifts and random errors are the dominant sources of error, with uncertainties in {omega}{sub c}/2{pi} and Q{sub c} in the range of 50 kHz and 25, respectively. The ABA method is applied to eliminate these drifts and minimize the random errors. For measurements over 25 ABA cycles, accuracy is improved to 0.14 kHz for {omega}{sub c}/2{pi} and 3 for Q{sub c}. The temperature variation over a single ABA cycle is generally on the order of 10{sup -3}-10{sup -5} deg. C and there is no need for any further temperature stabilization or correction measures. The overall uncertainty in the 10 GHz effective linewidth determinations for a 3 mm diam, 0.5 mm thick polycrystalline yttrium iron garnet (YIG) disk is 0.15 Oe or less, well below the intrinsic single crystal YIG linewidth. This represents a factor of 10 improvement in measurement accuracy over previous work.
Mo, Nan; Green, Jerome J.; Beitscher, Bailey A.; Patton, Carl E. [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States)
Astrometric detection and mass determination of Earth-mass exoplanets require sub-{mu}as accuracy, which is theoretically possible with an imaging space telescope using field stars as an astrometric reference. The measurement must, however, overcome astrometric distortions, which are much larger than the photon noise limit. To address this issue, we propose to generate faint stellar diffraction spikes using a two-dimensional grid of regularly spaced small dark spots added to the surface of the primary mirror (PM). Accurate astrometric motion of the host star is obtained by comparing the position of the spikes to the background field stars. The spikes do not contribute to scattered light in the central part of the field and therefore allow unperturbed coronagraphic observation of the star's immediate surroundings. Because the diffraction spikes are created on the PM and imaged on the same focal plane detector as the background stars, astrometric distortions affect equally the diffraction spikes and the background stars and are therefore calibrated. We describe the technique, detail how the data collected by the wide-field camera are used to derive astrometric motion, and identify the main sources of astrometric error using numerical simulations and analytical derivations. We find that the 1.4 m diameter telescope, 0.3 deg{sup 2} field we adopt as a baseline design achieves 0.2 {mu}as single measurement astrometric accuracy. The diffractive pupil concept thus enables sub-{mu}as astrometry without relying on the accurate pointing, external metrology, or high-stability hardware required with previously proposed high-precision astrometry concepts.
Guyon, Olivier; Eisner, Josh A.; Angel, Roger; Woolf, Neville J. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Bendek, Eduardo A.; Milster, Thomas D. [College of Optical Sciences, University of Arizona, Tucson, AZ 85721 (United States); Mark Ammons, S. [Lawrence Livermore National Laboratory, Physics Division L-210, 7000 East Ave., Livermore, CA 94550 (United States); Shao, Michael; Shaklan, Stuart; Levine, Marie; Nemati, Bijan [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Pitman, Joe [Exploration Sciences, P.O. Box 24, Pine, CO 80470 (United States); Woodruff, Robert A. [2081 Evergreen Avenue, Boulder, CO 80304 (United States); Belikov, Ruslan, E-mail: email@example.com [NASA Ames Research Center, Moffett Field, CA 94035 (United States)
A new method to eliminate the noise of vacuum microelectronic high precision accelerometer
The vacuum microelectronic high precision accelerometer was developed based on the vacuum field emission theory; it has many advantages such as high precision, good linearity in theory, but the inherent low frequency such as 1\\/f noise of the accelerometer decreases the signal-to-noise ratio greatly, and it is the main influencing factors to precision and linearity of accelerometer. In this paper
Hai-Tao Liu; Zhi-Yu Wen; Li Chen; Zhong-Quan Wen; Xue-Feng He
High-precision topographic information from all available data is crucial to many landing site geological and engineering applications. At the same time, precise navigation and localization of the rover as it traverses the Martian surface is important both for its safety and for the achievement of its engineering and scientific objectives. In this paper, we investigate a new approach to high-precision
Kaichang Di; Fengliang Xu; Ron Li; Larry H. Matthies; Clark F. Olson
Precision Density Measurements Near the Helium Lambda Transition Using High-Q Microwave Cavities
NASA Astrophysics Data System (ADS)
A new experimental approach for high-precision density measurements of liquid helium near the lambda transition is proposed. Using a high-Q Nb microwave cavity (Q ~ 10^10) and the high-resolution thermometry (HRT), the changes in the density of helium that fills the cavity can be detected to high precision by accurate measurements of the resonant frequency shift (? f) as a function of the temperature. Since the frequency shift provides direct information for the changes in the dielectric constant, and since the dielectric constant is related to the density through the Clausius-Mossotti relation, the capability of high resolution frequency measurements (to one part in 10^13) will enable us to resolve density changes to one part in 10^10. Numerical calculations have been performed to demonstrate the feasibility of this approach for mapping out the density profile of liquid helium which couples to the TE modes of a microwave cavity. For temperatures very near the lambda transition, a superfluid-normal fluid interface develops inside the cavity. A numerical algorithm is established to resolve the helium density profile in the cavity. Preliminary experimental data using a TM010 Nb cavity and with microkelvin temperature resolutions will be presented. *Supported by NASA contract and Packard Foundation.
Strayer, D. M.; Jiang, W.; Yeh, N.-C.; Asplund, N.
Ultra-High Precision Half-Life Measurement for the Superallowed &+circ; Emitter ^26Al^m
NASA Astrophysics Data System (ADS)
The calculated nuclear structure dependent correction for ^26Al^m (?C-?NS= 0.305(27)% [1]) is smaller by nearly a factor of two than the other twelve precision superallowed cases, making it an ideal case to pursue a reduction in the experimental errors contributing to the Ft value. An ultra-high precision half-life measurement for the superallowed &+circ; emitter ^26Al^m has been made using a 4? continuous gas flow proportional counter as part of an ongoing experimental program in superallowed Fermi ? decay studies at the Isotope Separator and Accelerator (ISAC) facility at TRIUMF in Vancouver, Canada, which delivered a beam of ś10^5 ^26Al^m/s in October 2007. With a statistical precision of ś0.008%, the present work represents the single most precise measurement of any superallowed half-life to date. [1] I.S. Towner and J.C. Hardy, Phys. Rev. C 77, 025501 (2008).
Finlay, P.; Demand, G.; Garrett, P. E.; Leach, K. G.; Phillips, A. A.; Sumithrarachchi, C. S.; Svensson, C. E.; Triambak, S.; Ball, G. C.; Bandyopadhyay, D.; Djongolov, M.; Ettenauer, S.; Hackman, G.; Pearson, C. J.; Williams, S. J.; Andreoiu, C.; Cross, D.; Austin, R. A. E.; Grinyer, G. F.; Leslie, J. R.
Ramsey method of separated oscillatory fields for high-precision penning trap mass spectrometry.
Ramsey's method of separated oscillatory fields is applied to the excitation of the cyclotron motion of short-lived ions in a Penning trap to improve the precision of their measured mass values. The theoretical description of the extracted ion-cyclotron-resonance line shape is derived and its correctness demonstrated experimentally by measuring the mass of the short-lived 38Ca nuclide with an uncertainty of 1.1 x 10(-8) using the Penning trap mass spectrometer ISOLTRAP at CERN. The mass of the superallowed beta emitter 38Ca contributes for testing the theoretical corrections of the conserved-vector-current hypothesis of the electroweak interaction. It is shown that the Ramsey method applied to Penning trap mass measurements yields a statistical uncertainty similar to that obtained by the conventional technique but 10 times faster. Thus the technique is a new powerful tool for high-precision mass measurements. PMID:17501414
George, S; Baruah, S; Blank, B; Blaum, K; Breitenfeldt, M; Hager, U; Herfurth, F; Herlert, A; Kellerbauer, A; Kluge, H-J; Kretzschmar, M; Lunney, D; Savreux, R; Schwarz, S; Schweikhard, L; Yazidjian, C
Precision optical slit for high heat load or ultra high vacuum
This invention relates generally to slits used in optics that must be precisely aligned and adjusted. The optical slits of the present invention are useful in x-ray optics, x-ray beam lines, optical systems in which the entrance slit is critical for high wavelength resolution. The invention is particularly useful in ultra high vacuum systems where lubricants are difficult to use and designs which avoid the movement of metal parts against one another are important, such as monochrometers for high wavelength resolution with ultra high vacuum systems. The invention further relates to optical systems in which temperature characteristics of the slit materials is important. The present invention yet additionally relates to precision slits wherein the opposing edges of the slit must be precisely moved relative to a center line between the edges with each edge retaining its parallel orientation with respect to the other edge and/or the center line.
Andresen, Nord C. (Hayward, CA); DiGennaro, Richard S. (Albany, CA); Swain, Thomas L. (Richmond, CA)
Precision optical slit for high heat load or ultra high vacuum
This invention relates generally to slits used in optics that must be precisely aligned and adjusted. The optical slits of the present invention are useful in x-ray optics, x-ray beam lines, optical systems in which the entrance slit is critical for high wavelength resolution. The invention is particularly useful in ultra high vacuum systems where lubricants are difficult to use and designs which avoid the movement of metal parts against one another are important, such as monochromators for high wavelength resolution with ultra high vacuum systems. The invention further relates to optical systems in which temperature characteristics of the slit materials is important. The present invention yet additionally relates to precision slits wherein the opposing edges of the slit must be precisely moved relative to a center line between the edges with each edge retaining its parallel orientation with respect to the other edge and/or the center line. 21 figures.
Andresen, N.C.; DiGennaro, R.S.; Swain, T.L.
The Mainz high-precision proton form factor measurement
NASA Astrophysics Data System (ADS)
Form factors offer a direct approach to fundamental properties of the nucleons like the radius and charge distribution. Renewed interest was stirred up by the 5 sigma discrepancy between a recent determination of the proton radius from the Lamb shift in muonic hydrogen and preceding electron scattering results. The low-q shape of the form factors might also contain a direct signal of a pion cloud around the nucleus and is a strong test of hadron models. In my talk, I will discuss the electron scattering experiment performed with the 3-spectrometer-facility of the A1 collaboration at MAMI in Mainz, Germany. The data set covers the Q^2-range from 0.004 to 1,(GeV/c)^2 and includes about 1400 separate cross section measurements, spanning the range of scattering angles from below 20^o to above 120^o at six beam energies between 180 and 855,eV, with statistical uncertainties below 0.4%. The 3-spectrometer-setup allowed for a simultaneous monitoring of the luminosity and overlapping and redundant measurements of the cross section to achieve stringent control over systematic uncertainties. Beam stabilization systems and redundant current measurements further limit systematic effects. The measured cross sections were analyzed with the standard Rosenbluth separation technique and by employing direct fits of a large set of form factor models. The high redundancy of the data set allowed us to extract the form factors up to 0.6,(GeV/c)^2 with very small uncertainties and to give a new, precise value for the proton radius from electron scattering. From the form factors, the charge distribution and Zemach moments were calculated. The latter constitute important input for the theoretical corrections of the muonic Lamb shift experiment. However, the revised values can not explain the discrepancy. Further possible explanations include higher order QED-corrections, vacuum effects or even physics beyond the standard model.
Bernauer, Jan
Experimental Hypersonic Aerodynamic Characteristics of the 2001 Mars Surveyor Precision Lander with Flap
NASA Technical Reports Server (NTRS)
Aerodynamic wind-tunnel screening tests were conducted on a 0.029 scale model of a proposed Mars Surveyor 2001 Precision Lander (70 deg half angle spherically blunted cone with a conical afterbody). The primary experimental objective was to determine the effectiveness of a single flap to trim the vehicle at incidence during a lifting hypersonic planetary entry. The laminar force and moment data, presented in the form of coefficients, and shock patterns from schlieren photography were obtained in the NASA Langley Aerothermodynamic Laboratory for post-normal shock Reynolds numbers (based on forebody diameter) ranging from 2,637 to 92,350, angles of attack ranging from 0 tip to 23 degrees at 0 and 2 degree sideslip, and normal-shock density ratios of 5 and 12. Based upon the proposed entry trajectory of the 2001 Lander, the blunt body heavy gas tests in CF, simulate a Mach number of approximately 12 based upon a normal shock density ratio of 12 in flight at Mars. The results from this experimental study suggest that when traditional means of providing aerodynamic trim for this class of planetary entry vehicle are not possible (e.g. offset c.g.), a single flap can provide similar aerodynamic performance. An assessment of blunt body aerodynamic effects attributed to a real gas were obtained by synergistic testing in Mach 6 ideal-air at a comparable Reynolds number. From an aerodynamic perspective, an appropriately sized flap was found to provide sufficient trim capability at the desired L/D for precision landing. Inviscid hypersonic flow computations using an unstructured grid were made to provide a quick assessment of the Lander aerodynamics. Navier-Stokes computational predictions were found to be in very good agreement with experimental measurement.
Horvath, Thomas J.; OConnell, Tod F.; Cheatwood, F. McNeil; Prabhu, Ramadas K.; Alter, Stephen J.
A High Precision Scanning Control System For A VUV Fourier Transform Spectrometer
A VUV Fourier transform spectrometer based on a wavefront division interferometer has been built. Our ultimate goal is to provide a high resolution absorption spectrometer in the 140 - 40 nm range using the new third generation French synchrotron source Soleil as the background continuum. Here, we present the design and latest performance of the instrument scanning control system. It is based on multiple reflections of a monomode, frequency-stabilized HeNe laser between two plane mirrors allowing the required sensitivity on the displacement of the interferometer mobile arm. The experimental results on the sampling precision show an rms error below 5 nm for a travel length of 7.5 mm.
De Oliveira, N.; Nahon, L.; Polack, F. [Synchrotron Soleil-Orme des Merisiers St Aubin BP48 -91192 Gif sur Yvette (France); Joyeux, D.; Phalippou, D.; Rodier, J. C. [Laboratoire Charles Fabry de l'Institut d'Optique, bat. 503, F91403 Orsay (France); Vervloeet, M. [Laboratoire de Photophysique Moleculaire, bat. 350, F91403 Orsay (France)
High precision quantum control of single donor spins in silicon.
The Stark shift of the hyperfine coupling constant is investigated for a P donor in Si far below the ionization regime in the presence of interfaces using tight-binding and band minima basis approaches and compared to the recent precision measurements. In contrast with previous effective mass-based results, the quadratic Stark coefficient obtained from both theories agrees closely with the experiments. It is also shown that there is a significant linear Stark effect for an impurity near the interface, whereas, far from the interface, the quadratic Stark effect dominates. This work represents the most sensitive and precise comparison between theory and experiment for single donor spin control. Such precise control of single donor spin states is required particularly in quantum computing applications of single donor electronics, which forms the driving motivation of this work. PMID:17678301
Rahman, Rajib; Wellard, Cameron J; Bradbury, Forrest R; Prada, Marta; Cole, Jared H; Klimeck, Gerhard; Hollenberg, Lloyd C L
High precision ages from the Torres del Paine Intrusion, Chile
NASA Astrophysics Data System (ADS)
The upper crustal bimodal Torres del Paine Intrusion, southern Chile, consists of the lower Paine-Mafic- Complex and the upper Paine-Granite. Geochronologically this bimodal complex is not well studied except for a few existing data from Halpern (1973) and Sanchez (2006). The aim of this study is to supplement the existing data and to constrain the age relations between the major magmatic pulses by applying high precision U-Pb dating on accessory zircons and 40Ar/39Ar-laser-step-heating-ages on biotites from the Torres del Paine Intrusion. The magmatic rocks from mafic complex are fine to medium-grained and vary in composition from quartz- monzonites to granodiorites and gabbros. Coarse-grained olivine gabbros have intruded these rocks in the west. The granitic body is represented by a peraluminous, biotite-orthoclase-granite and a more evolved leucocratic granite in the outer parts towards the host-rock. Field observations suggest a feeder-zone for the granite in the west and that the granite postdates the mafic complex. Two granite samples of the outermost margins in the Northeast and South were analyzed. The zircons were dated by precise isotope-dilution U-Pb techniques of chemically abraded single grains. The data are concordant within the analytical error and define weighted mean 206/238U ages of 12.59 ▒ 0.03 Ma and 12.58 ▒ 0.01 Ma for the two samples respectively. A 40Ar/39Ar-age for the second sample yield a date of 12.37 ▒ 0.11 Ma. Three 40Ar/39Ar -ages of biotites were obtained for rocks belonging to the mafic complex. A hbl-bio- granodiorite from the central part, approximately 150 m below the subhorizontal contact with the granite, gives an age of 12.81 ▒ 0.11 Ma. A hbl-bio-granodiorite and an olivine-gabbro west of the feeder-zone date at 12.42 ▒ 0.14 Ma and 12.49 ▒ 0.11 Ma, respectively. The obtained older age of 12.81 Ma for the granodiorite in the central part is consistent with structural relationships of brittle fracturing of the mafic complex by the granite and we conclude that some parts of the mafic complex were emplaced before the granite. The well defined 206/238U-age for zircons and the slightly younger 40Ar/39Ar -ages for biotites of both rock suites show that emplacement and cooling of the Torres del Paine Intrusion took place in a relatively short time-frame. Halpern, 1973, Geological Society of America Bulletin, 84/7: 2407-2422. Sanchez et.al., 2006. V SSAGI, Punta del Este, April 2006.
Michel, J.; Baumgartner, L.; Cosca, M.; Ovtcharova, M.; Putlitz, B.; Schaltegger, U.
High delay precision based on dynamic phase-shift for range-gated laser imaging technology
NASA Astrophysics Data System (ADS)
The range-gated laser imaging technology has become a useful technique in many applications in recent years. In order to expand the range of imaging detection and improve the measurement range resolution of the imaging system, we used circular step advance delay sequence for the synchronous control. And we developed a method of using dynamic phase-shift technique in FPGA to improve the precision of the delay in the time sequence, which can make the precision of the delay stepper between the two adjacent frames less than global clock period of the FPGA and approach the limit of FPGA's operating frequency. That is to say, it can equivalently increase the clock frequency. Then we can effectively improve measurement range resolution of the imaging system. In this paper, we have studied how dynamic phase-shift technique can be equivalent to higher clock frequency and performed some experiments. We presented the structure of dynamic phase-shift technique used to improve the precision of delay in the synchronization control time sequence. And the simulation and experimental results are showed in this paper. The results demonstrate that using dynamic phase-shift technique in FPGA can make the precision of the delay between the ICCD's trigger pulse and the laser's trigger pulse reach 1ns, which means the resolution of measurement range can be 0.15m theoretically. The timing control signal with dynamic phase-shift technique designed in this paper can be widely used in range-gated imaging because of its high timing control precision and flexible parameter setting.
Cui, Wei; Fan, Song-tao; Wang, Xin-wei; Zhou, Yan
Development and Validation of High Precision Thermal, Mechanical, and Optical Models for the Space Interferometry Mission
NASA Technical Reports Server (NTRS)
SIM Planetquest (SIM) is a large optical interferometer for making microarcsecond measurements of the positions of stars, and to detect Earth-sized planets around nearby stars. To achieve this precision, SIM requires stability of optical components to tens of picometers per hour. The combination of SIM s large size (9 meter baseline) and the high stability requirement makes it difficult and costly to measure all aspects of system performance on the ground. To reduce risks, costs and to allow for a design with fewer intermediate testing stages, the SIM project is developing an integrated thermal, mechanical and optical modeling process that will allow predictions of the system performance to be made at the required high precision. This modeling process uses commercial, off-the-shelf tools and has been validated against experimental results at the precision of the SIM performance requirements. This paper presents the description of the model development, some of the models, and their validation in the Thermo-Opto-Mechanical (TOM3) testbed which includes full scale brassboard optical components and the metrology to test them at the SIM performance requirement levels.
Lindensmith, Chris A.; Briggs, H. Clark; Beregovski, Yuri; Feria, V. Alfonso; Goullioud, Renaud; Gursel, Yekta; Hahn, Inseob; Kinsella, Gary; Orzewalla, Matthew; Phillips, Charles
High precision, time-resolved CCD photometry of stellar ensembles
NASA Astrophysics Data System (ADS)
Use of CCDs to monitor simultaneously a large ensemble of stars allows for subsequent photometric calibration, limited only by basic counting statistics of the objects and background, and atmospheric scintillation noise. With the large well depth of TEK CCDs it is possible to attain relative precisions (in a time-series for individual stars) of 0.001 mag per one minute integration on stars of 13th mag on a 0.9 m telescope. Two critical reduction/analysis procedures required to reach consistently the fundamental precision limits will be outlined. The oral presentation of this paper included several preliminary results from a multisite, two week campaign monitoring the central region of M67; these results will be published elsewhere. This paper concentrates on discussion of point-spread-function fitting of poorly sampled images, and the cleaning of stellar intensity time series.
Gilliland, Ronald L.
Ion source for high-precision mass spectrometry
The invention is directed to a method for increasing the precision of positive-ion relative abundance measurements conducted in a sector mass spectrometer having an ion source for directing a beam of positive ions onto a collimating slit. The method comprises incorporating in the source an electrostatic lens assembly for providing a positive-ion beam of circular cross section for collimation by the slit.
Todd, Peter J. (Oak Ridge, TN); McKown, Henry S. (Oak Ridge, TN); Smith, David H. (Oak Ridge, TN)
High precision measurements with nuclear emulsions using fast automated microscopes
We report on the development of an automated scanning system for nuclear emulsions aiming at very precise spatial and angular measurements. An accuracy of 0.06?m in position was achieved with the emulsion films used for the measurement. An accuracy of 0.4mrad was achieved for tracks penetrating orthogonally the emulsion films while an accuracy of 1mrad was obtained for tracks inclined
M. De Serio; M. Ieva; M. T. Muciaccia; S. Simone; M. Cozzi; G. Giacomelli; L. Patrizii; G. Sirri; S. Blokhin; S. Buontempo; D. Coppola; N. DÆAmbrosio; G. De Lellis; P. Migliozzi; C. Pistillo; P. Strolin; V. Tioukov; E. Barbuto; C. Bozza; G. Grella; C. Sirignano
Gauges for Highly Precise Metrology of a Compound Mirror
NASA Technical Reports Server (NTRS)
Three optical gauges have been developed for guiding the assembly and measuring precisely the reflecting surfaces of a compound mirror that comprises a corner-cube retroreflector glued in a hole on a flat mirror. In the specific application for which the gauges were developed, the compound mirror is part of a siderostat in a stellar interferometer. The flat-mirror portion of the compound mirror is the siderostat mirror; the retroreflector portion of the compound mirror is to be used, during operation of the interferometer, to monitor the location of the siderostat mirror surface relative to other optical surfaces of the interferometer. Nominally, the optical corner of the retroreflector should lie precisely on the siderostat mirror surface, but this precision cannot be achieved in fabrication: in practice, there remains some distance between the optical corner and the siderostat mirror surface. For proper operation of the interferometer, it is required to make this distance as small as possible and to know this distance within 1 nm. The three gauges make it possible to satisfy these requirements.
Gursel, Yekta
Vibratory response modeling and verification of a high precision optical positioning system.
A generic vibratory-response modeling program has been developed as a tool for designing high-precision optical positioning systems. Based on multibody dynamics theory, the system is modeled as rigid-body structures connected by linear elastic elements, such as complex actuators and bearings. The full dynamic properties of each element are determined experimentally or theoretically, then integrated into the program as inertial and stiffness matrices. Utilizing this program, the theoretical and experimental verification of the vibratory behavior of a double-multilayer monochromator support and positioning system is presented. Results of parametric design studies that investigate the influence of support floor dynamics and highlight important design issues are also presented. Overall, good matches between theory and experiment demonstrate the effectiveness of the program as a dynamic modeling tool.
Barraza, J.; Kuzay, T.; Royston, T. J.; Shu, D.
Power spectral density integration analysis and its application to large bandwidth, high precision position measurements
NASA Astrophysics Data System (ADS)
High precision position measurements often involve the detection of a laser beam that interacts with various components of an experimental setup. In order to achieve the highest precision, instabilities that contribute to a decrease in precision must be identified and quantified. Instabilities include fluctuations in the laser power, fluctuations in the laser pointing and fluctuations in the phase, as well as vibrating mechanical components that are susceptible to excitations and drift. Instabilities lead to unwanted resonances and band structures in the power spectral density of the detector signals. Typically, the most important instabilities are identified by the magnitude and location of resonances or bands in the power spectral density. However, power spectral density plots can be misleading if the width or shape of a resonance or a band are not correctly accounted for. This is especially true for measurements that span a large bandwidth. Here, we discuss Power Spectral Density Integration Analysis as a more intuitive and accurate method for identifying and quantifying instabilities. Resonances and bands are readily identified as step-like features with heights that correctly represent their contribution to the error in the position measurement.
Kochanczyk, Martin D.; Bartsch, Tobias F.; Taute, Katja M.; Florin, Ernst-Ludwig
High-precision tilt stage for the high-voltage electron microscope.
The high-voltage electron microscope is used to study thick samples (0.25 to several micrometers) to obtain three-dimensional information at ultrastructural resolution. Three-dimensional image reconstructions are often employed to extract, process and display this information. The sets of images used to form reconstructions must be recorded for precisely known specimen-beam orientations, especially if tomographic methods are employed. The design and operation of a precision (+/- 0.06 degrees) single-tilt stage to support this type of imaging is reported. All motions including two translations, height adjustment and tilting are accomplished via a single objective lens entry port. The specimen rod is supported on two rubber gaskets for vibration isolation, and motorized precision micrometers with encoder readouts for position monitoring drive the motions. The stage is stable to 0.6 nm for at least 16 s and is capable of tilt angles of +/- 70 degrees. PMID:3238811
Turner, J N; Barnard, D P; Matuszek, G; See, C W
High-current high-precision openable-core AC and AC\\/DC current transformers
The application of an electronic technique, which greatly increases the apparent permeability of the magnetic core of a current transformer, to high-current high-precision openable-core AC and AC\\/DC current transformers is described. The openable-core AC\\/DC current transformer can be used to measure accurately alternating current only or direct current only, or both alternating and direct currents simultaneously. Test results of two
Eddy So; Shiyan Ren; David A. Bennett
High-Precision Radial Velocity Measurements of Some Southern Stars
NASA Astrophysics Data System (ADS)
Precise absolute radial velocities have been obtained at Mount John University Observatory for a number of southern stars, using the 1 m telescope and fiber-fed echelle spectrograph. Only the stars that have been observed three or more times are presented, including 14 IAU standards and 11 program stars. Six echelle orders in the green (5000-5600 ┼) are used. Many delicate steps have been undertaken in order to maintain the same conditions in both recording and reducing the spectra over a period of 27 months. The Th-Ar lamp has been used for the wavelength calibration. The absolute radial velocities have been determined by cross-correlation with synthetic spectra computed by R. L. Kurucz. The zero point has been adjusted using blue-sky spectra. An additional strong correlation, between the measured velocities and photon counts in stellar and Th-Ar spectra, has been detected for the PM3000 CCD camera and has been eliminated. A resulting precision of about 20-30 m s-1 has been obtained. The overall uncertainty of the absolute radial velocities was estimated to be about 100-200 m s-1. The present paper is a continuation of our recent previous work, including more details on the reduction process and the presentation of the radial velocities for more stars.
Skuljan, Jovan; Hearnshaw, John B.; Cottrell, Peter L.
High-precision analysis of SF6 at ambient level
NASA Astrophysics Data System (ADS)
This work reports on the development of a technique for the precise analysis of ambient SF6. This technique, which involves a gas chromatograph/electron capture detector (GC-ECD) coupled with an Activated Alumina-F1 (AA-F1) column, performed well in the measurements, particularly in terms of accuracy, which complies with the World Meteorological Organization (WMO)-recommended compatibility of 0.02 ppt. Compared to the Porapak Q technique, we observed a sharper peak shape for the SF6 stream, which substantiates the improvement in the analytical precision. The traceability to the WMO scale was tested by calibrating the GC-ECD/AA-F1 analyser using five SF6 standards provided by the WMO/Global Atmosphere Watch (GAW) Central Calibration Laboratory (CCL) for SF6 (NOAA, United States of America). After calibration by various methods, the GC-ECD/AA-F1 accurately estimated the mole fraction of SF6 in the working standard prepared by the World Calibration Centre for SF6 operated by the Korea Meteorological Administration (KMA)/Korea Research Institute of Standards and Science (KRISS). Among the calibration methods, the two-point calibration method emerged to be the most economical procedure in terms of the data quality and measurement time. It was found that the KRISS scale of SF6/N2 was biased by 0.13 ppt when compared to the WMO scale of SF6/air; this bias is probably due to a different matrix.
Lim, J. S.; Moon, D. M.; Kim, J. S.; Yun, W.-T.; Lee, J.
Application of Liner Implosions to High Precision EOS Measurements (U).
National Technical Information Service (NTIS)
The All-Russia Research Institute of Experimental Physics (VNIIEF), and Los Alamos National Laboratory (LANL) have mutual interests in studies of the study of instabilities, liner compression and behavior of materials as extreme conditions using pulsed-po...
B. Reinovsky
High-Precision UPb Zircon Dates as Benchmarks in Absolute Time
High-precision IDTIMS U-Pb zircon dates provide the most precise and accurate isotopic benchmarks in absolute time, due to the concordancy check of the paired U-Pb decay schemes, the precisely measured 235U and 238U decay constants, very high initial parent\\/daughter ratios, and the robust nature of zircon to loss or gain of U and Pb over geologic time. However, caveats to
M. D. Schmitz; S. A. Bowring; B. Schoene
Advanced imaging system for high-precision, high-resolution CCD imaging
NASA Astrophysics Data System (ADS)
The Advanced Imaging System is a slow scan, high precision CCD camera system designed specifically for low noise image acquisition and precise, highly flexible CCD testing and characterization. In addition, the system is designed to allow CCD mosaics to be supported with separate, programmable clock voltages and output amplifier operating points for each device. A high speed digital signal processor acts as the timing generator and allows all clock voltages and timing states to be adjusted through a set of downloadable parameters. Virtually any CCD can be operated with modest changes to the system hardware and software. In addition, the entire control program may be downloaded from the host computer at any time to facilitate radically different camera operation. The initial version of the camera system supports up to eight separate simultaneous readout channels with readout rates as high as 100 kHz at 16 bit precision and noise levels below 5 e- at 50 kHz. Control and data signals are connected to the host computer through a fiber optic interface for maximum distance and isolation. The system is a highly flexible CCD camera designed to operate individual CCDs and mosaics in slow scan systems where low noise is of primary importance.
Doherty, Peter E.; Sims, Gary R.
A high precision, compact electromechanical ground rotation sensor.
We present a mechanical rotation sensor consisting of a balance pivoting on a tungsten carbide knife edge. These sensors are important for precision seismic isolation systems, as employed in land-based gravitational wave interferometers and for the new field of rotational seismology. The position sensor used is an air-core linear variable differential transformer with a demonstrated noise floor of 1 ū 10?╣╣ m/?Hz. We describe the instrument construction and demonstrate low noise operation with a noise floor upper bound of 5.7 ū 10?? rad/?Hz at 10 mHz and 6.4 ū 10?╣? rad/?Hz at 0.1 Hz. The performance of the knife edge hinge is compatible with a behaviorur free of noise from dislocation self-organized criticality. PMID:24880388
Dergachev, V; DeSalvo, R; Asadoor, M; Bhawal, A; Gong, P; Kim, C; Lottarini, A; Minenkov, Y; Murphy, C; O'Toole, A; Pe±a Arellano, F E; Rodionov, A V; Shaner, M; Sobacchi, E
A high precision, compact electromechanical ground rotation sensor
NASA Astrophysics Data System (ADS)
We present a mechanical rotation sensor consisting of a balance pivoting on a tungsten carbide knife edge. These sensors are important for precision seismic isolation systems, as employed in land-based gravitational wave interferometers and for the new field of rotational seismology. The position sensor used is an air-core linear variable differential transformer with a demonstrated noise floor of {1}{ ū 10^{-11}}textrm { m}/sqrt{textrm {Hz}}. We describe the instrument construction and demonstrate low noise operation with a noise floor upper bound of {5.7}{ ū 10^{-9}}textrm { rad}/sqrt{textrm {Hz}} at 10 mHz and {6.4}{ ū 10^{-10}}textrm { rad}/sqrt{textrm {Hz}} at 0.1 Hz. The performance of the knife edge hinge is compatible with a behaviorur free of noise from dislocation self-organized criticality.
Dergachev, V.; DeSalvo, R.; Asadoor, M.; Bhawal, A.; Gong, P.; Kim, C.; Lottarini, A.; Minenkov, Y.; Murphy, C.; O'Toole, A.; Pe±a Arellano, F. E.; Rodionov, A. V.; Shaner, M.; Sobacchi, E.
High Precision Measurements of the Pion Proton Differential Elastic Cross Section in the Second Resonance Region
NASA Astrophysics Data System (ADS)
One of the main sources of the information about nuclear resonances are partial wave analyses (PWA) of pion-proton elastic scattering. Nearly all of the data available for PWA were obtained more than 20 years ago with old measurement techniques. The talk presents new high precision data obtained recently by the EPECUR collaboration. The experiment features high statistics and better than 1 MeV resolution in the invariant mass thus allowing searches for narrow resonances with the coupling to the ?p channel as low as 5%. The experimental setup consists of a 25 cm long liquid hydrogen target in a non-magnetic spectrometer of wire drift chambers with hexagonal structure. The measurements started in 2009. 3 billions of triggers are already collected with positive and negative pion beams in the beam momentum range 820-1330 MeV/c.
Alekseev, I. G.; Bordyuzhin, I. G.; Kalinkin, D. V.; Koroleva, L. I.; Morozov, B. V.; Nesterov, V. M.; Ryltsov, V. V.; Shestakova, M. M.; Shurygin, B. M.; Smirnov, P. S.; Sulimov, A. D.; Svirida, D. N.; Andreev, V. A.; Filimonov, Ye. A.; Golubev, V. V.; Gridnev, A. B.; Konovalova, E. A.; Kozlenko, N. G.; Kozlov, V. S.; Krivshich, A. G.; Kuznetsov, V. A.; Novinsky, D. V.; Sumachev, V. V.; Tarakanov, V. I.; Trautman, V. Yu.; Sadler, M.
We present the results of a three year monitoring program of a sample of very low mass (VLM) field binaries using both astrometric and spectroscopic data obtained in conjunction with the laser guide star adaptive optics system on the W. M. Keck II 10 m telescope. Among the 24 systems studied, 15 have undergone sufficient orbital motion, allowing us to derive their relative orbital parameters and hence their total system mass. These measurements more than double the number of mass measurements for VLM objects, and include the most precise mass measurement to date (<2%). Among the 11 systems with both astrometric and spectroscopic measurements, six have sufficient radial velocity variations to allow us to obtain individual component masses. This is the first derivation of the component masses for five of these systems. Altogether, the orbital solutions of these low mass systems show a correlation between eccentricity and orbital period, consistent with their higher mass counterparts. In our primary analysis, we find that there are systematic discrepancies between our dynamical mass measurements and the predictions of theoretical evolutionary models (TUCSON and LYON) with both models either underpredicting or overpredicting the most precisely determined dynamical masses. These discrepancies are a function of spectral type, with late-M through mid-L systems tending to have their masses underpredicted, while one T-type system has its mass overpredicted. These discrepancies imply that either the temperatures predicted by evolutionary and atmosphere models are inconsistent for an object of a given mass, or the mass-radius relationship or cooling timescales predicted by the evolutionary models are incorrect. If these spectral-type trends are correct and hold into the planetary mass regime, the implication is that the masses of directly imaged extrasolar planets are overpredicted by the evolutionary models.
Konopacky, Q. M.; Ghez, A. M.; McLean, I. S. [University of California, Los Angeles, Division of Astronomy and Astrophysics, Los Angeles, CA 90095-1562 (United States); Barman, T. S. [Lowell Observatory, 1400 W. Mars Hill Road, Flagstaff, AZ 86001 (United States); Rice, E. L. [American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192 (United States); Bailey, J. I. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48105 (United States); White, R. J. [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303 (United States); Duchene, G., E-mail: email@example.com, E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com, E-mail: email@example.com, E-mail: email@example.com [Astronomy Department, University of California, Berkeley, 601 Campbell Hall, Berkeley, CA 94720-3411 (United States)
Vibration suppression and damage detection in smart composite laminate using high precision finite element
The present work has proposed a 2-D triangular high precision finite element (HPFE) based on Classical Laminated Plate Theory (CLPT). This high precision plate element with 38 degrees of freedom is used to obtain fundamental frequencies and the mode shapes of a passive composite plate. A standard FEM package-ABAQUS is used to verify the FEM code and to validate the
Anand Kumar; Peter J. Fleming; Bishakh Bhattacharya
High-speed precision weighing of pharmaceutical capsules
NASA Astrophysics Data System (ADS)
In this paper, we present a cost-effective method for fast and accurate in-line weighing of hard gelatin capsules based on the optimized capacitance sensor and real-time processing of the capsule capacitance profile resulting from 5000 capacitance measurements per second. First, the effect of the shape and size of the capacitive sensor on the sensitivity and stability of the measurements was investigated in order to optimize the performance of the system. The method was tested on two types of hard gelatin capsules weighing from 50 mg to 650 mg. The results showed that the capacitance profile was exceptionally well correlated with the capsule weight with the correlation coefficient exceeding 0.999. The mean precision of the measurements was in the range from 1 mg to 3 mg, depending on the size of the capsule and was significantly lower than the 5% weight tolerances usually used by the pharmaceutical industry. Therefore, the method was found feasible for weighing pharmaceutical hard gelatin capsules as long as certain conditions are met regarding the capsule fill properties and environment stability. The proposed measurement system can be calibrated by using only two or three sets of capsules with known weight. However, for most applications it is sufficient to use only empty and nominally filled capsules for calibration. Finally, a practical application of the proposed method showed that a single system is capable of weighing around 75 000 capsules per hour, while using multiple systems could easily increase the inspection rate to meet almost any requirements.
B³rmen, Miran; PernuÜ, Franjo; Likar, BoÜtjan
High-precision timeline for Earth's most severe extinction.
The end-Permian mass extinction was the most severe loss of marine and terrestrial biota in the last 542 My. Understanding its cause and the controls on extinction/recovery dynamics depends on an accurate and precise age model. U-Pb zircon dates for five volcanic ash beds from the Global Stratotype Section and Point for the Permian-Triassic boundary at Meishan, China, define an age model for the extinction and allow exploration of the links between global environmental perturbation, carbon cycle disruption, mass extinction, and recovery at millennial timescales. The extinction occurred between 251.941 ▒ 0.037 and 251.880 ▒ 0.031 Mya, an interval of 60 ▒ 48 ka. Onset of a major reorganization of the carbon cycle immediately precedes the initiation of extinction and is punctuated by a sharp (3ē), short-lived negative spike in the isotopic composition of carbonate carbon. Carbon cycle volatility persists for ?500 ka before a return to near preextinction values. Decamillenial to millennial level resolution of the mass extinction and its aftermath will permit a refined evaluation of the relative roles of rate-dependent processes contributing to the extinction, allowing insight into postextinction ecosystem expansion, and establish an accurate time point for evaluating the plausibility of trigger and kill mechanisms. PMID:24516148
Burgess, Seth D; Bowring, Samuel; Shen, Shu-zhong
Application of a high speed digitizer to high-precision nuclear ?-decay lifetime measurements
NASA Astrophysics Data System (ADS)
The objective of this study is to probe the feasibility of applying a high-speed digitizer to precise lifetime measurements of super-allowed nuclear ?-emitters in order to improve the achievable precision. Instead of using analogy modules to discriminate and count decay events, we have developed a digital counting method based on an 8-bit digitizer with a 1 GS/s sampling rate, which records the waveforms from our gas proportional counter for later software analysis. The digitizer and our analysis software have been extensively tested on the saved waveforms from off-line radioactive-source measurements as well as from on-line experiments. A software filter has been designed, tested and applied successfully to separate true ? events from spurious signals by pulse-shape analysis. The methods used for, and the results obtained from, our first two on-line test experiments in 2010 will be described in detail. This work demonstrates the first successful application of a high-speed digitizer and off-line digital signal processing techniques to high precision nuclear ?-decay lifetime measurements.
Chen, Lixin; Hardy, John
High frequency ultrasonic transducers are needed for high spatial resolution measurements in applications such as medical diagnosis and non- destructive testing. However, cost-effective fabrication of high performance transducers with frequencies above 20 MHz is challenging because of the need for a thin layer of active material. Piezocomposites are the material of choice in such transducers at lower frequencies, but current
S. Cochran; H. Hughes; M. Ponting
Design of a High-Precision 3D-Coordinate Measuring Machine
In Precision Engineering components are getting smaller and tolerances become tighter, so demands for accuracy are increasing. To improve the precision of Coordinate Measuring Machines (CMMs) we designed an alternative high precision 3D-CMM with measuring uncertainty beneath 0.1 ?m in a measuring volume of 1 dm3. The machine design is based on the Abbe and Bryan principle, thus smaller measuring
M. M. P. A. Vermeulen; P. C. J. N. Rosielle; P. H. J. Schellekens
PENTATRAP: a novel cryogenic multi-Penning-trap experiment for high-precision mass measurements on highly charged ions
NASA Astrophysics Data System (ADS)
The novel five-Penning-trap mass spectrometer Pentatrap is developed at the Max-Planck-Institut f³r Kernphysik (MPIK), Heidelberg. Ions of interest are long-lived highly charged nuclides up to bare uranium. Pentatrap aims for an accuracy of a few parts in 1012 for mass ratios of mass doublets. A physics program for Pentatrap includes Q-value measurements of ?-transitions relevant for neutrino physics, stringent tests of quantum electrodynamics in the regime of extreme electric fields, and a test of special relativity. Main features of Pentatrap are an access to a source of highly charged ions, a multi-trap configuration, simultaneous measurements of frequencies, a continuous precise monitoring of magnetic field fluctuations, a fast exchange between different ions, and a highly sensitive cryogenic non-destructive detection system. This article gives a motivation for the new mass spectrometer Pentatrap, presents its experimental setup, and describes the present status.
Repp, J.; B÷hm, C.; Crespo L¾pez-Urrutia, J. R.; D÷rr, A.; Eliseev, S.; George, S.; Goncharov, M.; Novikov, Y. N.; Roux, C.; Sturm, S.; Ulmer, S.; Blaum, K.
High-speed precision tracking with harmonic drive systems using integral manifold control design
Harmonic drives are popular in precision positioning applications such as military radars, satellite cameras, and wafer alignment machines because of their unique property of near-zero backlash. However, precision positioning performance is degraded by non-linear effects of inherent kinematic error and flexibility. This paper presents new non-linear controller development along with experimental verification to compensate for kinematic error in the presence
P. S. Gandhi; F. Ghorbel
Precision motion control with a high gain disturbance compensator for linear motors.
In this paper, we address the problem relating to the precision control of permanent magnet linear motors to track repeated motion trajectories. A high gain disturbance compensator is developed to improve the control performance degraded due to the presence of significant disturbances. An inverse gain of the overall system model is used to set up a disturbance observer. The observed disturbance is then used to generate a "knocker" signal, to be augmented to the control signal, which can provide the additional energy necessary to overcome the effects of the disturbances. A learning scheme is used to adjust the knocker signal iteratively over the repeated cycles. Simulation and experimental results are furnished to demonstrate the effectiveness of the proposed control scheme. PMID:15272795
Tan, Kok Kiong; Zhao, Shao
A High Precision Feature Based on LBP and Gabor Theory for Face Recognition
How to describe an image accurately with the most useful information but at the same time the least useless information is a basic problem in the recognition field. In this paper, a novel and high precision feature called BG2D2LRP is proposed, accompanied with a corresponding face recognition system. The feature contains both static texture differences and dynamic contour trends. It is based on Gabor and LBP theory, operated by various kinds of transformations such as block, second derivative, direct orientation, layer and finally fusion in a particular way. Seven well-known face databases such as FRGC, AR, FERET and so on are used to evaluate the veracity and robustness of the proposed feature. A maximum improvement of 29.41% is achieved comparing with other methods. Besides, the ROC curve provides a satisfactory figure. Those experimental results strongly demonstrate the feasibility and superiority of the new feature and method.
Xia, Wei; Yin, Shouyi; Ouyang, Peng
High-precision control of LSRM based X-Y table for industrial applications.
The design of an X-Y table applying direct-drive linear switched reluctance motor (LSRM) principle is proposed in this paper. The proposed X-Y table has the characteristics of low cost, simple and stable mechanical structure. After the design procedure is introduced, an adaptive position control method based on online parameter identification and pole-placement regulation scheme is developed for the X-Y table. Experimental results prove the feasibility and its priority over a traditional PID controller with better dynamic response, static performance and robustness to disturbances. It is expected that the novel two-dimensional direct-drive system find its applications in high-precision manufacture area. PMID:22981303
Pan, J F; Cheung, Norbert C; Zou, Yu
High precision predictions for exclusive V H production at the LHC
NASA Astrophysics Data System (ADS)
We present a resummation-improved prediction for pp ? V H + 0 jets at the Large Hadron Collider. We focus on highly-boosted final states in the presence of jet veto to suppress the background. In this case, conventional fixed-order calculations are plagued by the existence of large Sudakov logarithms for Q ~ m V + m H which lead to unreliable predictions as well as large theoretical uncertainties, and thus limit the accuracy when comparing experimental measurements to the Standard Model. In this work, we show that the resummation of Sudakov logarithms beyond the next-to-next-to-leading-log accuracy, combined with the next-to-next-to-leading order calculation, reduces the scale uncertainty and stabilizes the perturbative expansion in the region where the vector bosons carry large transverse momentum. Our result improves the precision with which Higgs properties can be determined from LHC measurements using boosted Higgs techniques.
Li, Ye; Liu, Xiaohui
Precision rectification of high resolution satellite imagery without ephemeris data
The huge capability of high resolution satellite imageries (HRSI), that includes spatial, spectral, temporal and radiometric resolutions as well as stereoscopic vision introduces them as a powerful new source for the Photogrammetry, Remote Sensing and GIS communities. High resolution data increases the need for higher accuracy of data modeling. The satellite orbit, position, attitude angles and interior orientation parameters have
Saeid Sadeghian; Mohammad Javad Valadan Zoej; Mahmoud Reza Delavar; Ahmad Abootalebi
High speed, precision motion strategies for lightweight structures
NASA Technical Reports Server (NTRS)
Abstracts of published papers and dissertations generated during the reporting period are compiled. Work on fine motion control was completed. Specifically, real time control of flexible manipulator vibrations were experimentally investigated. A linear model based on the application of Lagrangian dynamics to a rigid body mode and a series of separable flexible modes was examined with respect to model order requirements, and modal candidate selection. State feedback control laws were implemented based upon linear quadratic regulator design. Specification of the closed loop poles in the regulator design process was obtained by inclusion of a prescribed degree of stability in the manipulator model. Work on gross motion planning and control is also summarized. A systematic method to symbolically derive the full nonlinear dynamic equations of motion of multi-link flexible manipulators was developed.
Book, Wayne J.
High Precision Analysis of Blast Events on Highway Bridges.
National Technical Information Service (NTIS)
There has been increased awareness about safety of highway bridges from intentional/unintentional blast loads. This report focuses on the investigation of behavior of various bridge components during blast loads through a high fidelity finite element mode...
A. K. Agrawal Z. Yi
Ball Bearing Evaluation for a High Precision Radiometer Mirror Drive.
National Technical Information Service (NTIS)
Rolling element bearings are considered for use with a rotating scanning mirror requiring extremely high pointing accuracy and low jitter on the rotational speed. The mirror is used in the ocean color monitor of COMSS. A theoretical assessment of possible...
M. J. Todd A. J. Walton
High-precision automatic online measurement system of engine block top surface holes
NASA Astrophysics Data System (ADS)
The measurement of holes in the engine block top surface determines the general coupling effect of the engine. All of these holes are strictly restricted by the requirements of the dimensional tolerance and the geometrical tolerance, which determines the final engine quality. At present, these holes are measured mostly by the coordinate measuring machine (CMM) in the production line, and meeting the industry demands of automation, rapidity, and online testing with the method is difficult. A new rapid solution measuring the holes in the engine block top surface is proposed, which is based on the combination of multiple visual sensors. The flexible location method of the block is designed, and the global data fusion model based on multiple visual sensors is studied. Finally, the unified correction model of the lens distortion and the system inclination is proposed, and a revised system model with more precision is researched. The CMM measures the holes sizes and the spatial relationship between holes, and the data obtained are substituted into the global data fusion model to complete the system on-site rapid calibration. The experimental results show that the scheme is feasible. The measurement system can meet the production line needs of intelligence, rapidity, and high precision.
Yongqiang, Shi; Changku, Sun; Yukun, Ma; Hongxu, Duan; Peng, Wang
High Precision Thin CMOS Sensors for Future Vertex Detectors
NASA Astrophysics Data System (ADS)
CMOS pixel sensors are developed at IReS-LEPSI since 1999 for future vertex detectors needing very high granularity and minimal material budget. The first prototypes, made of small arrays of a few thousands of pixels, demonstrated the viability of the technology and its high tracking performances. In the last two years, new results on the radiation tolerance and tracking performances of the sensors were obtained, and the first real scale prototype was fabricated and tested. Moreover, a new manufacturing technology was investigated, without epitaxial layer but based on a lightly doped substrate. The contribution summarises the performances observed and provides an outlook on the sensor applications.
Winter, M.; Besson, A.; Deveaux, M.; Gay, A.; Gaycken, G.; Grandjean, D.; Himmi, A.; Hu, C.; Valin, I.; Claus, G.; Colledani, C.; Deptuch, G.; Dulinski, W.
High-precision wavelength-flexible frequency division for metrology
We realize and investigate wavelength-flexible phase-coherent all-optical frequency division by 2. Frequency division is obtained via self-phase-locking in a degenerate continuous-wave (cw) optical parametric oscillator (OPO). The wavelength flexibility of the divider is based on the use of quasi-phase-matching with perpendicular polarizations of the OPO output waves (type II). Mutual injection of the subharmonic waves is achieved by using an intracavity quarter-wave plate. A locking range of up to 160 MHz is observed experimentally, and a stable, self-phase-locked operation of the OPO is achieved over typically 15 min. For the first time, we measure the frequency stability of the divider by recording the relative phases of the subharmonic waves as a function of time. For a measurement time interval of 40 s, we measure a residual frequency instability of the divider of 8x10{sup -18}. We demonstrate a full control of the OPO's output-wave phase difference and observe the related change in power ratio of the subharmonic waves in agreement with the theoretically expected behavior. We propose that this possibility to monitor the divider's drift within the locking range via the power ratio can be used for stabilizing that drift in order to achieve a significant improvement of the long-term stability of the divide-by-2 OPO.
Gross, Petra; Boller, Klaus-Jochen; Klein, Marvin E. [Department of Applied Physics, University of Twente, 7500 AE Enschede (Netherlands); Art Innovation b.v., Zutphenstraat 25, 7575 EJ Oldenzaal (Netherlands)
Pointing Control System for a High Precision Flight Telescope
A pointing control system is developed and tested for a flying gimbaled telescope. The two-axis pointing system is capable of sub-microradian pointing stability and high accuracy in the presence of large host vehicle jitter. The telescope also has high agility--it is capable of a 50-degree retarget (in both axes simultaneously) in less than 2 seconds. To achieve the design specifications, high-accuracy, high-resolution, two-speed resolvers were used, resulting in gimbal-angle measurements stable to 1.5 microradians. In addition, on-axis inertial angle displacement sensors were mounted on the telescope to provide host-vehicle jitter cancellation. The inertial angle sensors are accurate to about 100 nanoradians, but do not measure low frequency displacements below 2 Hz. The gimbal command signal includes host-vehicle attitude information, which is band-limited. This provides jitter data below 20 Hz, but includes a variable latency between 15 and 25 milliseconds. One of the most challenging aspects of this design was to combine the inertial-angle-sensor data with the less perfect information in the command signal to achieve maximum jitter reduction. The optimum blending of these two signals, along with the feedback compensation were designed using Quantitative Feedback Theory.
A novel laser triangulation technique for high precision distance measurement
The authors describe an optical triangulation technique for noncontact distance measurement which yields high accuracy with a large depth of field and stand-off from the target. The theoretical error of this gauging technique is 0.5 ?m over a depth of field of 2 mm at distance of 100 mm from an optically rough target. The only limitation placed on the
D. S. Pierce; T. S. Ng; B. R. Morrison
Animal Experimentation in High Schools
ERIC Educational Resources Information Center
Recommends that teacher and student be provided with the broadest possible spectrum of meaningful and feasible experiments in which the comfort of the experimental animal is protected by the design of the experiment. (BR)
Ansevin, Kystyna D.
Multistage chemical etching for high-precision frequency adjustment in ultrahigh-frequency fundamental quartz resonators
Chemical etching to precisely adjust and to make uniform the thicknesses of vibrating areas of multiple resonators in a single wafer was applied to inverted-mesa quartz resonators exciting an ultrahigh-frequency fundamental thickness vibration. The process consisted of five stages, combining high-rate etching for high productivity and low-rate etching for high-precision adjustment. By using this process, the resonance frequencies of 41
H. Iwata
High-precision covariant one-boson-exchange potentials for np scattering below 350 MeV
NASA Astrophysics Data System (ADS)
Using the covariant spectator theory (CST), we have found one-boson-exchange (OBE) potentials that fit the 2006 world np data below 350 MeV with a ?2/ N data very close to 1, for a total of 3788 data. Our potentials have significantly fewer adjustable parameters than previous high-precision potentials, and they also reproduce the experimental triton binding energy without introducing additional irreducible three-nucleon forces.
Gross, F.; Stadler, A.
Ultrasmooth, highly spherical monocrystalline gold particles for precision plasmonics.
Ultrasmooth, highly spherical monocrystalline gold particles were prepared by a cyclic process of slow growth followed by slow chemical etching, which selectively removes edges and vertices. The etching process effectively makes the surface tension isotropic, so that spheres are favored under quasi-static conditions. It is scalable up to particle sizes of 200 nm or more. The resulting spherical crystals display uniform scattering spectra and consistent optical coupling at small separations, even showing Fano-like resonances in small clusters. The high monodispersity of the particles we demonstrate should facilitate the self-assembly of nanoparticle clusters with uniform optical resonances, which could in turn be used to fabricate optical metafluids. Narrow size distributions are required to control not only the spectral features but also the morphology and yield of clusters in certain assembly schemes. PMID:24219591
Lee, You-Jin; Schade, Nicholas B; Sun, Li; Fan, Jonathan A; Bae, Doo Ri; Mariscal, Marcelo M; Lee, Gaehang; Capasso, Federico; Sacanna, Stefano; Manoharan, Vinothan N; Yi, Gi-Ra
Precision Measurement of the Negative Pion Mass and the Experimental Verification of the Klein-Gordon Equation
A new precision measurement of the negative pion mass was. obtained by detecting the pionic x-rays of titanium (5g-4f) and. phosphorus (4f-3d) with a bent crystal spectrometer (139567 (+OR-). 1.00 keV\\/c('2)). The improvement in precision results from. improvements in the fractional energy resolution ((DELTA)E\\/E) by a factor. of four and in the signal-to-background ratio. High intensity sources. of pionic x-rays
Lynn Magolnick Delker
High precision moving magnet chopper for variable operation conditions
NASA Technical Reports Server (NTRS)
In the context of an ESTEC technology contract, a Chopping Mechanism was developed and built with the Far Infrared and Submillimeter Telescope (FIRST) astronomy mission as a reference. The task of the mechanism is to tilt the subreflector of the telescope with an assumed mass of 2.5 kg about one chopping axis at nominal frequencies of up to 5 Hz and chopping angles of up to +/- 11.25 mrad with high efficiency (minimum time for position change). The chopping axis is required to run through the subreflector vertex. After performing a concept trade-off also considering the low operational temperatures in the 130 K range, a design using moving magnet actuators was found to be the favorite one. In addition, a bearing concept using flexible pivots was chosen to meet the high chopping accuracy required. With this approach, a very reliable design could be realized, since the actuators work without any mechanical contact between its moving and fixed parts, and the only bearings used are two flexible pivots supporting the subreflector mounting interface. The mechanism was completely built in titanium in a lightweight and stiff design. The moving magnet actuators were designed to meet the stringent requirements for minimum risetime (time necessary to move from one angular position to a new one) in the 20 msec range. The angular position and the corresponding chopping frequency as well can be arbitrarily selected by the user.
Aicher, Winfried; Schmid, Manfred
A high precision radiation-tolerant LVDT conditioning module
NASA Astrophysics Data System (ADS)
Linear variable differential transformer (LVDT) position sensors are widely used in particle accelerators and nuclear plants, thanks to their properties of contact-less sensing, radiation tolerance, infinite resolution, good linearity and cost efficiency. Many applications require high reading accuracy, even in environments with high radiation levels, where the conditioning electronics must be located several hundred meters away from the sensor. Sometimes even at long distances the conditioning module is still exposed to ionizing radiation. Standard off-the-shelf electronic conditioning modules offer limited performances in terms of reading accuracy and long term stability already with short cables. A radiation tolerant stand-alone LVDT conditioning module has been developed using Commercial Off-The-Shelf (COTS) components. The reading of the sensor output voltages is based on a sine-fit algorithm digitally implemented on an FPGA ensuring few micrometers reading accuracy even with low signal-to-noise ratios. The algorithm validation and board architecture are described. A full metrological characterization of the module is reported and radiation tests results are discussed.
Masi, A.; Danzeca, S.; Losito, R.; Peronnard, P.; Secondo, R.; Spiezia, G.
High-precision metrology of highly charged ions via relativistic resonance fluorescence.
Resonance fluorescence of laser-driven highly charged ions is investigated with regard to precisely measuring atomic properties. For this purpose an ab initio approach based on the Dirac equation is employed that allows for studying relativistic ions. These systems provide a sensitive means to test correlated relativistic dynamics, quantum electrodynamic phenomena and nuclear effects by applying x-ray lasers. We show how the narrowing of sidebands in the x-ray fluorescence spectrum by interference due to an additional optical driving can be exploited to determine atomic dipole or multipole moments to unprecedented accuracy. PMID:21405269
Postavaru, O; Harman, Z; Keitel, C H
High-precision high-sensitivity clock recovery circuit for a mobile payment application
NASA Astrophysics Data System (ADS)
This paper presents a fully integrated carrier clock recovery circuit for a mobile payment application. The architecture is based on a sampling-detection module and a charge pump phase locked loop. Compared with clock recovery in conventional 13.56 MHz transponders, this circuit can recover a high-precision consecutive carrier clock from the on/off keying (OOK) signal sent by interrogators. Fabricated by a SMIC 0.18-?m EEPROM CMOS process, this chip works from a single power supply as low as 1.5 V Measurement results show that this circuit provides 0.34% frequency deviation and 8 mV sensitivity.
Lichong, Sun; Wenliang, Ren; Na, Yan; Hao, Min
SEMICONDUCTOR INTEGRATED CIRCUITS: A high precision high PSRR bandgap reference with thermal hysteresis protection
NASA Astrophysics Data System (ADS)
To meet the accuracy requirement for the bandgap voltage reference by the increasing data conversion precision of integrated circuits, a high-order curvature-compensated bandgap voltage reference is presented employing the characteristic of bipolar transistor current gain exponentially changing with temperature variations. In addition, an over-temperature protection circuit with a thermal hysteresis function to prevent thermal oscillation is proposed. Based on the CSMC 0.5 ?m 20 V BCD process, the designed circuit is implemented; the active die area is 0.17 ū 0.20 mm2. Simulation and testing results show that the temperature coefficient is 13.7ppm/K with temperature ranging from -40 to 150 ░C, the power supply rejection ratio is -98.2 dB, the line regulation is 0.3 mV/V, and the power consumption is only 0.38 mW. The proposed bandgap voltage reference has good characteristics such as small area, low power consumption, good temperature stability, high power supply rejection ratio, as well as low line regulation. This circuit can effectively prevent thermal oscillation and is suitable for on-chip voltage reference in high precision analog, digital and mixed systems.
Yintang, Yang; Yani, Li; Zhangming, Zhu
High precision pointing with a multiline spectrometer at the VTT
NASA Astrophysics Data System (ADS)
We are investigating the pointing quality of the VTT, Tenerife under the aspect of suitability for long-term heliosesimological observations. Tests have shown that thermal and mechanical loads within the telescope may create spurious image drifts with shift rates of up to 5 arcsec per hour. During daylong recordings this will reduce significantly the effective size of the field-of-view and may infer artificial lateral movements into the data. The underlying problem that not all image position offsets developing during a measurement may be compensated for is common to most high-resolution solar telescopes independently of the type of pointing system used. We are developing new approaches to address this problem which are to be tested in the near future at the VTT. The simulations established so far show that the problem may be reduced by more than 90 %.
Staiger, J.
Conditional DNA repair mutants enable highly precise genome engineering
Oligonucleotide-mediated multiplex genome engineering is an important tool for bacterial genome editing. The efficient application of this technique requires the inactivation of the endogenous methyl-directed mismatch repair system that in turn leads to a drastically elevated genomic mutation rate and the consequent accumulation of undesired off-target mutations. Here, we present a novel strategy for mismatch repair evasion using temperature-sensitive DNA repair mutants and temporal inactivation of the mismatch repair protein complex in Escherichia coli. Our method relies on the transient suppression of DNA repair during mismatch carrying oligonucleotide integration. Using temperature-sensitive control of methyl-directed mismatch repair protein activity during multiplex genome engineering, we reduced the number of off-target mutations by 85%, concurrently maintaining highly efficient and unbiased allelic replacement.
Nyerges, Akos; Csorgo, Balint; Nagy, Istvan; Latinovics, Dora; Szamecz, Bela; Posfai, Gyorgy; Pal, Csaba
High Precision Superconducting Cavity Diagnostics With Higher Order Mode Measurements
Experiments at the FLASH facility at DESY have demonstrated that the higher order modes induced in superconducting cavities can be used to provide a variety of beam and cavity diagnostics. The axes of the modes can be determined from the beam orbit that produces minimum power in the dipole HOM modes. The phase and amplitude of the dipole modes can be used to obtain high resolution beam position information, and the phase of the monopole modes to measure the beam phase relative to the accelerator rf. For most superconducting accelerators, the existing higher order mode couplers provide the necessary signals, and the downmix and digitizing electronics are straightforward, similar to those for a conventional beam position monitor.
Molloy, S.; Frisch, J.; McCormick, D.; May, J.; Ross, M.; Smith, T.; /SLAC; Baboi, N.; Hensler, O.; Petrosian, L.; /DESY; Napoly, O.; Paparella, R.C.; Simon, C.; /Saclay; Eddy, N.; Nagaitsev, S.; Wendt, M.; /Fermilab
High Precision SC Cavity Diagnostics with HOM Measurements
Experiments at the FLASH linac at DESY have demonstrated that the Higher Order Modes induced in Superconducting Cavities can be used to provide a variety of beam and cavity diagnostics. The centers of the cavities can be determined from the beam orbit which produces minimum power in the dipole HOM modes. The phase and amplitude of the dipole modes can be used as a high resolution beam position monitor, and the phase of the monopole modes to measure the beam phase relative to the accelerator RF. Beam orbit feedback which minimizes the dipole HOM power in a set of structures has been demonstrated. For most SC accelerators, the existing HOM couplers provide the necessary signals, and the down mix and digitizing electronics are straightforward, similar to those for a conventional BPM.
Frisch, Josef; Hendrickson, Linda; McCormick, Douglas; May, Justin; Molloy, Stephen; Ross, Marc; /SLAC
Development of a facility for high-precision irradiation of cells with carbon ions
Purpose: Compared to photons, using particle radiation in radiotherapy reduces the dose and irradiated volume of normal tissues, potentially reducing side effects. The biological effect of dose deposited by particles such as carbon ions, however, differs from that of dose deposited by photons. The inaccuracy in models to estimate the biological effects of particle radiation remains the most important source of uncertainties in particle therapy. Improving this requires high-precision studies on biological effects of particle radiation. Therefore, the authors aimed to develop a facility for reproducible and high-precision carbon-ion irradiation of cells in culture. The combined dose nonuniformity in the lateral and longitudinal direction should not exceed {+-}1.5%. Dose to the cells from particles than other carbon ions should not exceed 5%. Methods: A uniform lateral dose distribution was realized using a single scatter foil and quadrupole magnets. A modulator wheel was used to create a uniform longitudinal dose distribution. The choice of beam energy and the optimal design of these components was determined using GEANT4 and SRIM Monte Carlo simulations. Verification of the uniformity of the dose distribution was performed using a scintillating screen (lateral) and a water phantom (longitudinal). The reproducibility of dose delivery between experiments was assessed by repeated measurements of the spatial dose distribution. Moreover, the reproducibility of dose-response measurements was tested by measuring the survival of irradiated HEK293 cells in three independent experiments. Results: The relative contribution of dose from nuclear reaction fragments to the sample was found to be <5% when using 90 MeV/u carbon ions. This energy still allows accurate dosimetry conforming to the IAEA Report TRS-398, facilitating comparison to dose-effect data obtained with other radiation qualities. A 1.3 mm long spread-out Bragg peak with a diameter of 30 mm was created, allowing the irradiation of cell samples with the specified accuracy. Measurements of the transverse and longitudinal dose distribution showed that the dose variation over the sample volume was {+-}0.8% and {+-}0.7% in the lateral and longitudinal directions, respectively. The track-averaged LET of 132{+-}10 keV/{mu}m and dose-averaged LET of 189{+-}15 keV/{mu}m at the position of the sample were obtained from a GEANT4 simulation, which was validated experimentally. Three separately measured cell-survival curves yielded nearly identical results. Conclusions: With the new facility, high-precision carbon-ion irradiations of biological samples can be performed with highly reproducible results.
Goethem, Marc-Jan van; Niemantsverdriet, Maarten; Brandenburg, Sytze; Langendijk, Johannes A.; Coppes, Robert P.; Luijk, Peter van [Department of Cell Biology, Section of Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713AV Groningen (Netherlands); Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, P.O. Box 30001, 9700RB Groningen (Netherlands); Kernfysisch Versneller Instituut, University of Groningen, Zernikelaan 25, 9747AA Groningen (Netherlands); Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, P.O. Box 30001, 9700RB Groningen (Netherlands); Department of Cell Biology, Section of Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713AV Groningen (Netherlands); Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, P.O. Box 30001, 9700RB Groningen (Netherlands)
Integration Plan: World Class Manufacturing through the High Productivity and Precision Machining Program.
National Technical Information Service (NTIS)
The goal of the NCMS High Productivity and Precision Machining program is to advance the international competitive position of American machine tool builders and users. The machine tools selected for improvemet fall into three equipment types: machining c...
High precision fabrication and positioning of nanoelectrodes in a nanopore.
A simple and versatile method for the direct fabrication of tunneling electrodes with controllable gap distance by using electron-beam-induced deposition (EBID) is presented. We show that tunneling nanogaps smaller than the minimum feature size realizable by conventional EBID can be achieved with a standard scanning electron microscope. These gaps can easily be embedded in nanopores with high accuracy. The controllability of this fabrication method and the nanogap geometry was verified by SEM and TEM imaging. Furthermore, tunneling spectroscopy in a group of solvents with different barrier heights was used to determine the nanogap functionality. Ultimately, the presented fabrication method can be further applied for the fabrication of arrays of nanogap/nanopores or nanogap electrodes with tunable electrode materials. Additionally, this method can also offer direct fabrication of nanoscale electrode systems with tunable spacing for redox cycling and plasmonic applications, which represents an important step in the development of tunneling nanopore structures and in enhancing the capabilities of nanopore sensors. PMID:24446951
Ivanov, Aleksandar P; Freedman, Kevin J; Kim, Min Jun; Albrecht, Tim; Edel, Joshua B
A research of a high precision multichannel data acquisition system
NASA Astrophysics Data System (ADS)
The output signals of the focusing system in lithography are analog. To convert the analog signals into digital ones which are more flexible and stable to process, a desirable data acquisition system is required. The resolution of data acquisition, to some extent, affects the accuracy of focusing. In this article, we first compared performance between the various kinds of analog-to-digital converters (ADC) available on the market at the moment. Combined with the specific requirements (sampling frequency, converting accuracy, numbers of channels etc) and the characteristics (polarization, amplitude range etc) of the analog signals, the model of the ADC to be used as the core chip in our hardware design was determined. On this basis, we chose other chips needed in the hardware circuit that would well match with ADC, then the overall hardware design was obtained. Validation of our data acquisition system was verified through experiments and it can be demonstrated that the system can effectively realize the high resolution conversion of the multi-channel analog signals and give the accurate focusing information in lithography.
Zhong, Ling-na; Tang, Xiao-ping; Yan, Wei
High Precision Pulsar Timing: Effects of ISM Correction Schemes
NASA Astrophysics Data System (ADS)
Pulsar timing arrays are one of the leading methods in the search for gravitational waves (GWs). However a significant issue facing this method is the effect of the interstellar medium (ISM). There are multiple methodologies being used to correct for these effects but their efficacy has not been carefully studied. We conducted an initial study of biases induced by correcting for the interstellar medium. We simulated times of arrival (TOAs) with white noise and added ISM delays. We measure the ISM effects as is done with normal data, and created a model of these effects using polynomial fitting. This modeling method is most commonly used in the European Pulsar Timing Array. We then remove these measured ISM effects and compare final and initial TOAs. Ideally they should be the same; however, the differences between the 'corrected' TOAs and original TOAs reveal the weaknesses of this method. In preliminary results we concluded that the higher order polynomials do a better job, yet there is a limit as to how high an order one can use. We also found no significant systematic parameter bias induced by using this method. However, it is clear that certain parameters are more affected by this process of correction. The parameters most affected were the frequency and frequency derivative of the pulsar, but biases in these parameters are not important because the power due to them gets removed in the standard timing analysis. We are continuing this research by comparing and contrasting ISM correction schemes, as well as studying the actual behavior of the ISM in more detail. This research is supported by an NSF-PIRE and an NSF-AST grant.
Kunert, Willie; Verbiest, J. P. W.; Shannon, R.; Stinebring, D.
High-precision absolute distance and vibration measurement with frequency scanned interferometry
We report high-precision absolute distance and vibration measurements performed with frequency scanned interferometry using a pair of single-mode optical fibers. Absolute distance was determined by counting the interference fringes produced while scanning the laser frequency. A high-finesse Fabry-Perot interferometer was used to determine frequency changes during scanning. Two multiple-distance-measurement analysis techniques were developed to improve distance precision and to extract
Hai-Jun Yang; Jason Deibel; Sven Nyberg; Keith Riles
Ultrastable mirrors made from diamond reinforced SiC composites for high precision and power applications
NASA Astrophysics Data System (ADS)
Diamond reinforced reaction bonded silicon carbide composites have unique properties such as very high stiffness, low density, low thermal expansion coefficient and high thermal conductivity making them attractive materials for high precision optical and structural components. However, their use in high precision equipments was limited due to significant difficulties in high tolerance machining of these super hard composites. In this present work, machineable diamond reinforced SiC composites were fabricated through forming hybrid monolithic microstructures with diamond free machineable surfaces. The resulting machineable composites were used to produce ultra-stable mirror substrates with optional internal cooling channels for high power laser optic applications.
Akbas, M. A.; Mastrobattisto, D.; Vance, W.; Jurgaitis, P.; Aghajanian, M. K.
Assessing the precision of strain measurements using electron backscatter diffraction--part 2: experimental demonstration.
The residual impression after performing a microhardness indent in silicon has been mapped with high resolution EBSD to reveal residual elastic strain and lattice rotation fields. Mapping of the same area has been performed with variable pattern binning and exposure times to reveal the qualitative and quantitative differences resulting from reducing the pattern size and exposure time. Two dimension 'image' plots of these fields indicate that qualitative assessment of the shape and size of the fields can be performed with as much as 4ū4 binning. However, quantitative assessment using line scans reveals that the smoothest profile can be obtained using minimal pattern binning and long exposure times. To compare and contrast with these experimental maps, finite element analysis has been performed using a continuum damage-plasticity material law which has been independently calibrated to Si [9]. The constitutive law incorporates isotropic hardening in compression, and isotropic hardening and damage in tension. To accurately capture the localised damage which develops during indentation via the nucleation and propagation of cracks around the indentation site cohesive elements were assigned along the interfaces between the planes which experience the maximum traction. The residual strain state around the indenter and the size of the cracks agree very well with the experimentally measured value. PMID:24034981
Britton, T B; Jiang, J; Clough, R; Tarleton, E; Kirkland, A I; Wilkinson, A J
Charge Breeding Techniques in an Electron Beam Ion Trap for High Precision Mass Spectrometry at TITAN
NASA Astrophysics Data System (ADS)
Penning trap mass spectrometry is the most accurate and precise method available for performing atomic mass measurements. TRIUMF's Ion Trap for Atomic and Nuclear science is currently the only facility to couple its Penning trap to a rare isotope facility and an electron beam ion trap (EBIT). The EBIT is a valuable tool for beam preparation: since the precision scales linearly with the charge state, it takes advantage of the precision gained by using highly charged ions. However, this precision gain is contingent on fast and efficient charge breeding. An optimization algorithm has been developed to identify the optimal conditions for running the EBIT. Taking only the mass number and half-life of the isotope of interest as inputs, the electron beam current density, charge breeding time, charge state, and electron beam energy are all specified to maximize this precision. An overview of the TITAN charge breeding program, and the results of charge breeding simulations will be presented.
MacDonald, T. D.; Simon, M. C.; Bale, J. C.; Chowdhury, U.; Eibach, M.; Gallant, A. T.; Lennarz, A.; Simon, V. V.; Chaudhuri, A.; Grossheim, A.; Kwiatkowski, A. A.; Schultz, B. E.; Dilling, J.
High precision wavelength measurements of QED-sensitive forbidden transitions in highly charged argon ions.
We present the results of an experimental study of magnetic dipole (M1) transitions in highly charged argon ions (Ar X, Ar XI, Ar XIV, Ar XV) in the visible spectral range using an electron beam ion trap. Their wavelengths were determined with, for highly charged ions, unprecedented accuracy up to the sub-ppm level and compared with theoretical calculations. The QED contributions, calculated in this Letter, are found to be 4 orders of magnitude larger than the experimental error and are absolutely indispensable to bring theory and experiment to a good agreement. This method shows great potential for the study of QED effects in relativistic few-electron systems. PMID:14611279
Dragani?, I; Crespo L¾pez-Urrutia, J R; DuBois, R; Fritzsche, S; Shabaev, V M; Orts, R Soria; Tupitsyn, I I; Zou, Y; Ullrich, J
Ultra-High Precision Half-Life Measurement for the Superallowed &+circ; Emitter ^26Al^m
NASA Astrophysics Data System (ADS)
The calculated nuclear structure dependent correction for ^26Al^m (?C-?NS= 0.305(27)% [1]) is smaller by nearly a factor of two than the other twelve precision superallowed cases, making it an ideal case to pursue a reduction in the experimental errors contributing to the Ft value. An ultra-high precision half-life measurement for the superallowed &+circ; emitter ^26Al^m has been made at the Isotope Separator and Accelerator (ISAC) facility at TRIUMF in Vancouver, Canada. A beam of ś10^5 ^26Al^m/s was delivered in October 2007 and its decay was observed using a 4? continuous gas flow proportional counter as part of an ongoing experimental program in superallowed Fermi ? decay studies. With a statistical precision of ś0.008%, the present work represents the single most precise measurement of any superallowed half-life to date. [4pt] [1] I.S. Towner and J.C. Hardy, Phys. Rev. C 79, 055502 (2009).
Finlay, P.; Demand, G.; Garrett, P. E.; Leach, K. G.; Phillips, A. A.; Sumithrarachchi, C. S.; Svensson, C. E.; Triambak, S.; Grinyer, G. F.; Leslie, J. R.; Andreoiu, C.; Cross, D.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Djongolov, M.; Ettenauer, S.; Hackman, G.; Pearson, C. J.; Williams, S. J.
A rugged, high precision capacitance diaphragm low pressure gauge for cryogenic use
NASA Astrophysics Data System (ADS)
In order to carry out precise laboratory measurements of infrared absorption intensities, line profiles of molecules and organic volatile compounds for atmospheric chemistry in planetary and upper earth atmospheric layers, precise gas pressure measurement between 10-3 and a few mbars in the 77-300 K temperature range is necessary. A prototype, rugged, precision capacitive pressure gauge for cryogenic use has been designed, built at SOLEIL and tested down to 77 K. The design includes corrosion-resistant materials and has been tailored to operate on a differential measurement scheme based on a simple, precision capacitance-to-digital converter chip, instead of high precision floating capacitive bridges, as are used in other designs. The designs conception and performance specifications are presented here, illustrated by a precision of better than 1% in the 0.2-40 mbar range, with a resolution of 2 ū 10-3 mbar. The gauge is tunable and can be adjusted for higher precision and a better resolution, at the expense of the maximum high-pressure range.
Lago, Leatitia; Herbeaux, Christian; Bol, Marc; Roy, Pascale; Manceron, Laurent
A rugged, high precision capacitance diaphragm low pressure gauge for cryogenic use.
In order to carry out precise laboratory measurements of infrared absorption intensities, line profiles of molecules and organic volatile compounds for atmospheric chemistry in planetary and upper earth atmospheric layers, precise gas pressure measurement between 10(-3) and a few mbars in the 77-300 K temperature range is necessary. A prototype, rugged, precision capacitive pressure gauge for cryogenic use has been designed, built at SOLEIL and tested down to 77 K. The design includes corrosion-resistant materials and has been tailored to operate on a differential measurement scheme based on a simple, precision capacitance-to-digital converter chip, instead of high precision floating capacitive bridges, as are used in other designs. The designs conception and performance specifications are presented here, illustrated by a precision of better than 1% in the 0.2-40 mbar range, with a resolution of 2 ū 10(-3) mbar. The gauge is tunable and can be adjusted for higher precision and a better resolution, at the expense of the maximum high-pressure range. PMID:24517813
Lago, Leatitia; Herbeaux, Christian; Bol, Marc; Roy, Pascale; Manceron, Laurent
High-precision and high-accuracy rovibrational spectroscopy of molecular ions
NASA Astrophysics Data System (ADS)
We present a versatile new instrument capable of measuring rovibrational transition frequencies of molecular ions with sub-MHz accuracy and precision. A liquid-nitrogen cooled positive column discharge cell, which can produce large column densities of a wide variety of molecular ions, is probed with sub-Doppler spectroscopy enabled by a high-power optical parametric oscillator locked to a moderate finesse external cavity. Frequency modulation (heterodyne) spectroscopy is employed to reduce intensity fluctuations due to the cavity lock, and velocity modulation spectroscopy permits ion-neutral discrimination. The relatively narrow Lamb dips are precisely and accurately calibrated using an optical frequency comb. This method is completely general as it relies on the direct measurement of absorption or dispersion of rovibrational transitions. We expect that this new approach will open up many new possibilities: from providing new benchmarks for state-of-the-art ab initio calculations to supporting astronomical observations to helping assign congested spectra by combination differences. Herein, we describe the instrument in detail and demonstrate its performance by measuring ten R-branch transitions in the ?2 band of H3+, two transitions in the ?1 band of HCO+, and the first sub-Doppler transition of CH5+.
Hodges, James N.; Perry, Adam J.; Jenkins, Paul A.; Siller, Brian M.; McCall, Benjamin J.
High-Precision Half-Life and Branching Ratio Measurements for the Superallowed ?+ Emitter 26Alm
NASA Astrophysics Data System (ADS)
High-precision half-life and branching-ratio measurements for the superallowed ?+ emitter 26Alm were performed at the TRIUMF-ISAC radioactive ion beam facility. An upper limit of ? 15 ppm at 90% C.L. was determined for the sum of all possible non-analogue ?+/EC decay branches of 26Alm, yielding a superallowed branching ratio of 100.0000+0-0.0015%. A value of T1/2 = 6:34654(76) s was determined for the 26Alm half-life which is consistent with, but 2.5 times more precise than, the previous world average. Combining these results with world-average measurements yields an ft value of 3037.58(60) s, the most precisely determined for any superallowed emitting nucleus to date. This high-precision ft value for 26Alm provides a new benchmark to refine theoretical models of isospin-symmetry-breaking effects in superallowed ? decays.
Finlay, P.; Svensson, C. E.; Demand, G. A.; Garrett, P. E.; Green, K. L.; Leach, K. G.; Phillips, A. A.; Rand, E. T.; Ball, G.; Bandyopadhyay, D.; Djongolov, M.; Ettenauer, S.; Hackman, G.; Pearson, C. J.; Leslie, J. R.; Andreoiu, C.; Cross, D.; Austin, R. A. E.; Grinyer, G. F.; Sumithrarachchi, C. S.; Williams, S. J.; Triambak, S.
High-Precision Half-Life Measurement for the Superallowed ?+ Emitter Alm26
NASA Astrophysics Data System (ADS)
A high-precision half-life measurement for the superallowed ?+ emitter Alm26 was performed at the TRIUMF-ISAC radioactive ion beam facility yielding T1/2=6346.54▒0.46stat▒0.60systms, consistent with, but 2.5 times more precise than, the previous world average. The Alm26 half-life and ft value, 3037.53(61) s, are now the most precisely determined for any superallowed ? decay. Combined with recent theoretical corrections for isospin-symmetry-breaking and radiative effects, the corrected Ft value for Alm26, 3073.0(12) s, sets a new benchmark for the high-precision superallowed Fermi ?-decay studies used to test the conserved vector current hypothesis and determine the Vud element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix.
Finlay, P.; Ettenauer, S.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Andreoiu, C.; Austin, R. A. E.; Bandyopadhyay, D.; Cross, D. S.; Demand, G.; Djongolov, M.; Garrett, P. E.; Green, K. L.; Grinyer, G. F.; Hackman, G.; Leach, K. G.; Pearson, C. J.; Phillips, A. A.; Sumithrarachchi, C. S.; Triambak, S.; Williams, S. J.
Experimental High Energy Neutrino Astrophysics
Neutrinos are considered promising probes for high energy astrophysics. More than four decades after deep water Cerenkov technique was proposed to detect high energy neutrinos. Two detectors of this type are successfully taking data: BAIKAL and AMANDA. They have demonstrated the feasibility of the high energy neutrino detection and have set first constraints on TeV neutrino production astrophysical models. The quest for the construction of km3 size detectors have already started: in the South Pole, the IceCube neutrino telescope is under construction; the ANTARES, NEMO and NESTOR Collaborations are working towards the installation of a neutrino telescope in the Mediterranean Sea.
Distefano, Carla [Laboratori Nazionali del Sud, Catania (Italy)
High-precision wavelength calibration of astronomical spectrographs with laser frequency combs
We describe a possible new technique for precise wavelength calibration of high-resolution astronomical spectrographs using femtosecond-pulsed mode-locked lasers controlled by stable oscillators such as atomic clocks. Such `frequency combs' provide a series of narrow modes which are uniformly spaced according to the laser's pulse repetition rate and whose absolute frequencies are known a priori with relative precision better than 10-12.
M. T. Murphy; Th. Udem; R. Holzwarth; A. Sizmann; L. Pasquini; C. Araujo-Hauck; H. Dekker; S. D'Odorico; M. Fischer; T. W. Hõnsch; A. Manescau
New development of satellite laser ranging system for highly precise space and time measurements
The Communications Research Laboratory has developed a satellite laser ranging system as one facility in the Space Optical Communication Research Center in Tokyo, Japan. The system is equipped with a 1.5 m receiving telescope, 100 ps\\/100 mJ\\/10 Hz mode locked YAG laser and high precision receiver electronics. Terrestrial ranging with about 1000 shots normal point shows good precision of less
Hiroo Kunimori; Kuniyasu Imamura; Fujinobu Takahashi; Toshikazu Itabe; Tadashi Aruga; Atsushi Yamamoto
Machine Vision for High Precision Volume Measurement Applied to Levitated Containerless Materials Processing
NASA Technical Reports Server (NTRS)
By combining the best practices in optical dilatometry with new numerical methods, a high-speed and high precision technique has been developed to measure volume of levitated, containerlessly processed samples with sub- pixel resolution. Containerless processing provides the ability to study highly reactive materials without the possibility of contamination affecting thermo-physical properties. Levitation is a common technique used to isolate a sample as it is being processed. Noncontact optical measurement of thermo-ophysical properties is very important as traditional measuring methods cannot be used. Modern, digitally recorded images require advanced numerical routines to recover the sub-pixel locations of sample edges and, in turn produce high precision measurements.
Bradshaw, R. C.; Schmidt, D. P.; Rogers, J. R.; Kelton, K. F.; Hyers, R. W.
Use of terrestrial laser scanning technology for long term high precision deformation monitoring.
The paper presents a new methodology for high precision monitoring of deformations with a long term perspective using terrestrial laser scanning technology. In order to solve the problem of a stable reference system and to assure the high quality of possible position changes of point clouds, scanning is integrated with two complementary surveying techniques, i.e., high quality static GNSS positioning and precise tacheometry. The case study object where the proposed methodology was tested is a high pressure underground pipeline situated in an area which is geologically unstable. PMID:22303152
Vezo?nik, Rok; Ambro×i?, Toma×; Sterle, Oskar; Bilban, Gregor; Pfeifer, Norbert; Stopar, Bojan
Construction of a Versatile High Precision Ambient Ionization Source for Direct Analysis and Imaging
The design and construction of a high precision ambient ionization source matrix-assisted laser desorption electrospray ionization (MALDESI) is described in full detail including a complete parts list. The computer controlled high precision motion control system and high repetition rate Explorer laser are demonstrated during MALDESI-FT-ICR analysis of peptides and proteins ranging from 1¢17 kDa. The high stability ionization source platform described herein demonstrates both the advantages of the new MALDESI source and versatility for application to numerous desorption and ionization techniques.
Sampson, Jason S.; Hawkridge, Adam M.; Muddiman, David C.
Photoabsorption of atomic oxygen in the energy region below the 1s {sup -1} threshold in X-ray spectroscopy from Chandra and XMM-Newton is observed in a variety of X-ray binary spectra. Photoabsorption cross sections determined from an R-matrix method with pseudo-states and new, high precision measurements from the Advanced Light Source (ALS) are presented. High-resolution spectroscopy with E/{Delta}E Almost-Equal-To 4250 {+-} 400 was obtained for photon energies from 520 eV to 555 eV at an energy resolution of 124 {+-} 12 meV FWHM. K-shell photoabsorption cross section measurements were made with a re-analysis of previous experimental data on atomic oxygen at the ALS. Natural line widths {Gamma} are extracted for the 1s {sup -1}2s {sup 2}2p {sup 4}({sup 4} P)np {sup 3} P Degree-Sign and 1s {sup -1}2s {sup 2}2p {sup 4}({sup 2} P)np {sup 3} P Degree-Sign Rydberg resonances series and compared with theoretical predictions. Accurate cross sections and line widths are obtained for applications in X-ray astronomy. Excellent agreement between theory and the ALS measurements is shown which will have profound implications for the modeling of X-ray spectra and spectral diagnostics.
McLaughlin, B. M. [Centre for Theoretical Atomic, Molecular and Optical Physics (CTAMOP), School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN (United Kingdom); Ballance, C. P. [Department of Physics, 206 Allison Laboratory, Auburn University, Auburn, AL 36849-5311 (United States); Bowen, K. P.; Gardenghi, D. J.; Stolte, W. C., E-mail: firstname.lastname@example.com, E-mail: email@example.com, E-mail: firstname.lastname@example.com, E-mail: email@example.com, E-mail: firstname.lastname@example.com [Department of Chemistry, University of Nevada, Las Vegas, NV 89154-4003 (United States)
Initial Development of High Precision, High Resolution Ion Beam Spectrometer in the Near-Infrared
NASA Astrophysics Data System (ADS)
Interest in molecular ions stretches across many fields, from combustion to astrochemistry. These ions can be difficult to study spectroscopically in the laboratory, however. Obstacles include the relatively small density of ions produced in samples compared to neutral molecules and high rotational temperatures of the ions (which lead to dilution of the energy levels). To overcome some of these challenges of molecular ion spectroscopy, we are developing a fast ion beam spectrometer system we call Sensitive, Cooled, Resolved Ion BEam Spectroscopy (SCRIBES). This setup will enable the sensitive study of a supersonically cooled ion beam, taking advantage of narrow linewidths, a mass-dependent Doppler shift for mass identification of each spectral line, and on-line mass spectrometry for beam composition studies. Presently, the spectrometer contains an ion beam source that produces ions at high rotational temperature. We have characterized the spectrometer using the near-infrared rovibronic transitions of N_2^+, optimizing the sensitivity of the instrument. Furthermore, we have used an optical frequency comb for highly accurate frequency calibration, measuring a N_2^+ transition to within an accuracy of 8 MHz. This work in the near-infrared has laid the foundation for mid-infrared and indirect THz ion beam spectroscopy of many interesting molecular ions at a high level of precision, accuracy, and resolution.
Porambo, Michael; Siller, Brian; Mills, Andrew; Perera, Manori; Kreckel, Holger; McCall, Benjamin
Natural Vs. Precise Concise Languages for Human Operation of Computers: Research Issues and Experimental Approaches
This paper raises concerns that natural language front ends for computer systems can limit a researcher's scope of thinking, yield inappropriately complex systems, and exaggerate public fear of computers. Alternative modes of computer use are suggested and the role of psychologically oriented controlled experimentation is emphasized. Research methods and recent experimental results are briefly reviewed.
Ben Shneiderman
High-precision mapping of the magnetic field utilizing the harmonic function mean value property.
The spatial distributions of the static magnetic field components and MR phase maps in space with homogeneous magnetic susceptibility are shown to be harmonic functions satisfying Laplace's equation. A mean value property is derived and experimentally confirmed on phase maps: the mean value on a spherical surface in space is equal to the value at the center of the sphere. Based on this property, a method is implemented for significantly improving the precision of MR phase or field mapping. Three-dimensional mappings of the static magnetic field with a precision of 10(-11) approximately 10(-12) T are obtained in phantoms by a 1.5-T clinical MR scanner, with about three-orders-of-magnitude precision improvement over the conventional phase mapping technique. In vivo application of the method is also demonstrated on human leg phase maps. PMID:11237651
Li, L; Leigh, J S
Optical coherence tomography system with no high-precision scanning stage and stage controller.
Optical coherence tomography (OCT) is a novel technique for noninvasive imaging based on the use of a low-coherence interferometer. Conventionally, obtaining high-resolution images requires the use of high-precision sample and scanning stages and a stage controller for simultaneous measurement of the refractive index and the thickness of an optical sample. However, in this study a novel optical-fiber-type OCT system is developed that does not need both a high-precision scanning stage and a stage controller. Additionally, two signal demodulation processes are described. Compared with that of conventional OCT systems, the current configuration eliminates the high-precision scanning stage and stage controller and is therefore cheaper and less complex. Also, this new technique could be applied to conventional OCTs in biotissue scanning. PMID:15291056
Lo, Yu-Lung; Kuo, Chi-I; Chuang, Chin-Ho; Yan, Zhi-Zhong
High-precision laser beam shaping using a binary-amplitude spatial light modulator.
We have achieved high-precision laser beam shaping by using a binary-amplitude spatial light modulator, a digital micromirror device (DMD), followed by an imaging telescope that contains a pinhole low-pass filter (LPF). An error diffusion algorithm was used to design the initial DMD pixel pattern based on the measured input beam profile. This pattern was iteratively refined by simulating the optically low-pass filtered DMD image and changing DMD pixels to lift valleys and suppress peaks. We noted the gap between the experimental result of 1.4% root-mean-square (RMS) error and the simulated result for the same DMD pattern of 0.3% RMS error. Therefore, we deemed it necessary to introduce iterative refinement based on actual measurements of the output image to further improve the uniformity of the beam. Using this method, we have demonstrated the ability to shape raw, non-spatially filtered laser beams (quasi-Gaussian beams) into beams with precisely controlled profiles that have an unprecedented level of RMS error with respect to the target profile. We have shown that our iterative refinement process is able to improve the light intensity uniformity to around 1% RMS error in a raw camera image for both 633 and 1064 nm laser beams. The use of a digital LPF on the camera image is justified in that it matches the performance of the pinhole filter in the experimental setup. The digital low-pass filtered results reveal that the actual optical beam profiles have RMS error down to 0.23%. Our approach has also demonstrated the ability to produce a range of target profiles as long as they have similar spatial-frequency content (i.e., a slowly varying beam profile). Circular and square cross-section flat-top beams and beams with a linear intensity variation within a circular and square cross section were produced with similarly low RMS errors. The measured errors were about twice the ultimate limit of 0.1% RMS error based on the number of binary DMD pixels that participate in the beam-formation process. PMID:20220887
Liang, Jinyang; Kohn, Rudolph N; Becker, Michael F; Heinzen, Daniel J
High precision double-interferometry displacement measurement by waveform transforming based on FFT
NASA Astrophysics Data System (ADS)
The paper researches on a high precision displacement measurement system mixing double-wavelength interferometry and single-wavelength interferometry by waveform transforming based on Fast Fourier Transform (FFT) technology. The signal of double-wavelength interferometry is used for determining the amplitude of the measurand which makes the measurement range be as large as half a synthetic-wavelength, while that of single-wavelength interferometry is for measuring the value of the measurand precisely which endows the measurement resolution to be as high as less than 1nm, for the amount of the interference fringes of the signal of single-wavelength interferometry during the shifting range of the peak of the signal of double-wavelength interferometry demonstrates the value of the measurand. However, as the signal of double-wavelength interferometry is cosine amplitude modulated, the peak area of it is flatten and the peak position is difficult to be determined, which will influence the measurement precision directly. In order to address the peak position of the double-wavelength interferometric signal accurately, we transform using FFT technology the cosine amplitude modulated signal of double-wavelength interferometry into a triangle-wave amplitude modulated signal to make the peak position prominent. It is very easy to determine the peak position accurately and the amount of the interference fringes of the signal of single-wavelength interferometry during the shifting range of the peak will also be determined precisely. High precision displacement measurement with large range and high resolution could be realized.
Wang, Yunzhi; Xie, Fang; Ma, Sen
MATS and LaSpec: High-precision experiments using ion traps and lasers at FAIR
NASA Astrophysics Data System (ADS)
Nuclear ground state properties including mass, charge radii, spins and moments can be determined by applying atomic physics techniques such as Penning-trap based mass spectrometry and laser spectroscopy. The MATS and LaSpec setups at the low-energy beamline at FAIR will allow us to extend the knowledge of these properties further into the region far from stability. The mass and its inherent connection with the nuclear binding energy is a fundamental property of a nuclide, a unique ōfingerprintö. Thus, precise mass values are important for a variety of applications, ranging from nuclear-structure studies like the investigation of shell closures and the onset of deformation, tests of nuclear mass models and mass formulas, to tests of the weak interaction and of the Standard Model. The required relative accuracy ranges from 10-5 to below 10-8 for radionuclides, which most often have half-lives well below 1 s. Substantial progress in Penning trap mass spectrometry has made this method a prime choice for precision measurements on rare isotopes. The technique has the potential to provide high accuracy and sensitivity even for very short-lived nuclides. Furthermore, ion traps can be used for precision decay studies and offer advantages over existing methods. With MATS (Precision Measurements of very short-lived nuclei using an A_dvanced Trapping System for highly-charged ions) at FAIR we aim to apply several techniques to very short-lived radionuclides: High-accuracy mass measurements, in-trap conversion electron and alpha spectroscopy, and trap-assisted spectroscopy. The experimental setup of MATS is a unique combination of an electron beam ion trap for charge breeding, ion traps for beam preparation, and a high-precision Penning trap system for mass measurements and decay studies. For the mass measurements, MATS offers both a high accuracy and a high sensitivity. A relative mass uncertainty of 10-9 can be reached by employing highly-charged ions and a non-destructive Fourier-Transform Ion-Cyclotron-Resonance (FT-ICR) detection technique on single stored ions. This accuracy limit is important for fundamental interaction tests, but also allows for the study of the fine structure of the nuclear mass surface with unprecedented accuracy, whenever required. The use of the FT-ICR technique provides true single ion sensitivity. This is essential to access isotopes that are produced with minimum rates which are very often the most interesting ones. Instead of pushing for highest accuracy, the high charge state of the ions can also be used to reduce the storage time of the ions, hence making measurements on even shorter-lived isotopes possible. Decay studies in ion traps will become possible with MATS. Novel spectroscopic tools for in-trap high-resolution conversion-electron and charged-particle spectroscopy from carrier-free sources will be developed, aiming e.g. at the measurements of quadrupole moments and E0 strengths. With the possibility of both high-accuracy mass measurements of the shortest-lived isotopes and decay studies, the high sensitivity and accuracy potential of MATS is ideally suited for the study of very exotic nuclides that will only be produced at the FAIR facility.Laser spectroscopy of radioactive isotopes and isomers is an efficient and model-independent approach for the determination of nuclear ground and isomeric state properties. Hyperfine structures and isotope shifts in electronic transitions exhibit readily accessible information on the nuclear spin, magnetic dipole and electric quadrupole moments as well as root-mean-square charge radii. The dependencies of the hyperfine splitting and isotope shift on the nuclear moments and mean square nuclear charge radii are well known and the theoretical framework for the extraction of nuclear parameters is well established. These extracted parameters provide fundamental information on the structure of nuclei at the limits of stability. Vital information on both bulk and valence nuclear properties are derived and an exceptional sensitivity to changes in nuclear def
RodrĒguez, D.; Blaum, K.; N÷rtershõuser, W.; Ahammed, M.; Algora, A.; Audi, G.; ─yst÷, J.; Beck, D.; Bender, M.; Billowes, J.; Block, M.; B÷hm, C.; Bollen, G.; Brodeur, M.; Brunner, T.; Bushaw, B. A.; Cakirli, R. B.; Campbell, P.; Cano-Ott, D.; Cortķs, G.; Crespo L¾pez-Urrutia, J. R.; Das, P.; Dax, A.; de, A.; Delheij, P.; Dickel, T.; Dilling, J.; Eberhardt, K.; Eliseev, S.; Ettenauer, S.; Flanagan, K. T.; Ferrer, R.; GarcĒa-Ramos, J.-E.; Gartzke, E.; Geissel, H.; George, S.; Geppert, C.; G¾mez-Hornillos, M. B.; Gusev, Y.; Habs, D.; Heenen, P.-H.; Heinz, S.; Herfurth, F.; Herlert, A.; Hobein, M.; Huber, G.; Huyse, M.; Jesch, C.; Jokinen, A.; Kester, O.; Ketelaer, J.; Kolhinen, V.; Koudriavtsev, I.; Kowalska, M.; Krõmer, J.; Kreim, S.; Krieger, A.; K³hl, T.; Lallena, A. M.; Lapierre, A.; Le Blanc, F.; Litvinov, Y. A.; Lunney, D.; MartĒnez, T.; Marx, G.; Matos, M.; Minaya-Ramirez, E.; Moore, I.; Nagy, S.; Naimi, S.; Neidherr, D.; Nesterenko, D.; Neyens, G.; Novikov, Y. N.; Petrick, M.; Pla▀, W. R.; Popov, A.; Quint, W.; Ray, A.; Reinhard, P.-G.; Repp, J.; Roux, C.; Rubio, B.; Sßnchez, R.; Schabinger, B.; Scheidenberger, C.; Schneider, D.; Schuch, R.; Schwarz, S.; Schweikhard, L.; Seliverstov, M.; Solders, A.; Suhonen, M.; Szerypo, J.; TaĒn, J. L.; Thirolf, P. G.; Ullrich, J.; van Duppen, P.; Vasiliev, A.; Vorobjev, G.; Weber, C.; Wendt, K.; Winkler, M.; Yordanov, D.; Ziegler, F.
Doppler high precision extra-solar planet surveys by a fixed delay interferometer
A fixed delay interferometer combined with a post-disperser is a new technique for high precision radial velocity (RV) measurements. The Doppler measurements are conducted by monitoring the stellar fringe phase shifts of the interferometer instead of absorption line centroid shifts as in the echelle. High Doppler sensitivity is achieved through optimizing the optical delay in the interferometer and measuring multiple
Jian Ge; Julian C. van Eyken; Suvrath Mahadevan; Curtis DeWitt; Lawrence W. Ramsey; Stuart B. Shaklan; Xiaopei Pan
The use of elemental thermocouples in high-temperature precision thermometry
The properties of those elements (Au, Pd, Pt, Rh and Ir) potentially suitable for use in high-precision thermocouple thermometry at high temperatures are reviewed. Included is a discussion of their oxidation behaviour, the potential for contamination from their insulation and the effect of relative thermal expansion of the thermo-elements and of the insulation that contains them. The requirements for initial
Robin E. Bentley
Digital controller for Rapid Cycling Synchrotron magnet power supply with very high tracking precision
In Rapid Cycling Synchrotron, very high tracking precision is required for the magnets power supply, while the load is high order resonant network. In this paper, a digital PID controller combined with repetitive control algorithm is studied for such an application. Feedforward scheme is also adopted to reduce the tracking error under the periodical reference. A digital controller based on
Jin Ye; Xu Yang; Haizhong Ye; Xiaoming Kong; Liu Bo
Precision Measurements of the Ionization Energy and Its Temperature Variation in High Purity Silicon Radiation Detectors
High precision absolute measurements of the ionization energy (┐) for alpha particles and electrons have been made in two thick high purity silicon guard ring detectors between 100 K and 250 K. At a fixed energy (E) both ┐┐ and ┐e- were found to vary linearly (r = 0.999) with the band gap (WG). ┐┐ and ┐e- also increased with
R. D. Ryan
A modified highly precise direct integration method for a class of linear time-varying systems
NASA Astrophysics Data System (ADS)
It is always a bottleneck to design an effective algorithm for linear time-varying systems in engineering applications. For a class of systems, whose coefficients matrix is based on time-varying polynomial, a modified highly precise direct integration (VHPD-T method) was presented. Through introducing new variables and expanding dimensions, the system can be transformed into a time-invariant system, in which the transfer matrix can be computed for once and used forever with a highly precise direct integration method. The method attains higher precision than the common methods (e.g. RK4 and power series) and high efficiency in computation. Some numerical examples demonstrate the validity and efficiency of the method proposed.
Liu, XiaoMei; Zhou, Gang; Zhu, Shuai; Wang, YongHong; Sun, WeiRong; Weng, ShiLie
Gradient-based high precision alignment of cryo-electron subtomograms
Whole cell cryo-electron tomography emerges as an important component for structural system biology approaches. It allows the localization and structural characterization of macromolecular complexes in near living conditions. However, the method is hampered by low resolution, missing data and low signal-to-noise ratio (SNR). To overcome some of these difficulties one can align and average a large set of subtomograms. Existing alignment methods are mostly based on an exhaustive scanning and sampling of all but discrete relative rotations and translations of one subtomogram with respect to the other. In this paper, we propose a gradient-guided alignment method based on two subtomogram similarity measures. We also propose a stochastic parallel optimization that increases significantly the efficiency for the simultaneous refinement of a set of alignment candidates. Results on simulated data of model complexes and experimental structures of protein complexes show that even for highly distorted subtomograms and with only a small number of very sparsely distributed initial alignment seeds, our method can accurately recover true transformations with a significantly higher precision than scanning based alignment methods.
Xu, Min; Alber, Frank
Development of a low cost high precision three-layer 3D artificial compound eye.
Artificial compound eyes are typically designed on planar substrates due to the limits of current imaging devices and available manufacturing processes. In this study, a high precision, low cost, three-layer 3D artificial compound eye consisting of a 3D microlens array, a freeform lens array, and a field lens array was constructed to mimic an apposition compound eye on a curved substrate. The freeform microlens array was manufactured on a curved substrate to alter incident light beams and steer their respective images onto a flat image plane. The optical design was performed using ZEMAX. The optical simulation shows that the artificial compound eye can form multiple images with aberrations below 11 ?m; adequate for many imaging applications. Both the freeform lens array and the field lens array were manufactured using microinjection molding process to reduce cost. Aluminum mold inserts were diamond machined by the slow tool servo method. The performance of the compound eye was tested using a home-built optical setup. The images captured demonstrate that the proposed structures can successfully steer images from a curved surface onto a planar photoreceptor. Experimental results show that the compound eye in this research has a field of view of 87░. In addition, images formed by multiple channels were found to be evenly distributed on the flat photoreceptor. Additionally, overlapping views of the adjacent channels allow higher resolution images to be re-constructed from multiple 3D images taken simultaneously. PMID:24104115
Zhang, Hao; Li, Lei; McCray, David L; Scheiding, Sebastian; Naples, Neil J; Gebhardt, Andreas; Risse, Stefan; Eberhardt, Ramona; T³nnermann, Andreas; Yi, Allen Y
High-precision thermal strain measurements using surface-mounted fiber Bragg grating sensors
NASA Astrophysics Data System (ADS)
Thermal strain measurements by fiber Bragg grating (FBG) sensors mounted onto different host materials are demonstrated for low coefficients of thermal expansion (CTE). Such low CTEs are typically found in carbon fiber reinforced plastics (CFRP). This work has application potential for FBG sensor networks in the highprecision control of thermal deformations in structures or in curing monitoring. For this purpose, a thermal error model of the FBG sensor, which accounts for the thermo-optic coefficient and the thermal expansion of the FBG, was characterized experimentally. The error-model characterization method is based on reference measurements of FBGs bonded to ZERODUR ceramics. Using this error model, thermal strain can be measured by surface-mounted FBGs on any given host structure using an external temperature reference and the FBG's wavelength shift. This method is demonstrated successfully for unidirectional layers of CFRP with a CTE of -0.4 ┬Ę 10-6 1/K in fiber direction and for steel (316 Ti), which is commonly used in cryogenic applications. Measurements are performed for temperatures from 100K to 320K and the results are verified by high-precision dilatometer measurements. Accuracy limits of the FBG-based thermal strain measurements are discussed, as well as the minimization of errors induced by the FBG's structural interface. Further, the reduction of errors in the adhesive bonding is discussed. This work expands the understanding of the separation of thermal and mechanical effects in the signals obtained by FBGs.
Mueller, Uwe C.; Both, Jan; Roths, Johannes; Baier, Horst
High-precision measurement of an involute artefact by a rolling method and comparison between measuring instruments
NASA Astrophysics Data System (ADS)
The vibration of gears is a serious problem for machines. The characteristics of the vibration of gears are affected by tooth flank form deviation of submicrometre order. The quality of product gears is controlled by a gear-measuring instrument, which is calibrated by an involute artefact with high precision. A highly precise method for measuring the involute artefact by rolling has been proposed. However, this method does not yield sufficient accuracy. In this research, a novel rolling method for the involute artefact, a 'nonslip driving method', is proposed to achieve high accuracy. This method is compared with the conventional driving method by theoretical analysis of artefact motion. Moreover, its accuracy and effect are evaluated experimentally. The results show that this method is more stable on the basis of measurement results than the conventional driving method. Therefore, it is confirmed that the highly precise measurement of the involute artefact can be realized by incorporating the nonslip driving method into the rolling artefact method. In addition, measurement results for the involute artefact are compared among the proposed method and the methods involving the use of a coordinate measuring machine and a gear-measuring instrument.
Takeoka, Fumi; Komori, Masaharu; Kubo, Aizoh; Fujio, Hiroshige; Ito, Takehiro; Takatsuji, Toshiyuki; Osawa, Sonko; Sato, Osamu; Takeda, Ryohei
Precision eco-climatic division of high quality rice in Chongqing based on GIS
NASA Astrophysics Data System (ADS)
The present study was conducted to evaluate the relationship between the growth of high quality rice and climatic conditions, climatic resources of high quality rice in Chongqing, climatic disaster and main eco-climatic factors impacting on the distribution of high quality rice. Guidelines were built based on this study. In addition, by using 1:25 DEM, spatial distributed guidelines and GIS technique, precision eco-climatic division of high quality rice was established.
Gao, Yanghua; Chen, Zhijun; Mei, Yong; Tang, Yunhui; Li, Yonghua; Ju, Lihui; Yuan, Desheng
Adjusting for High-dimensional Covariates in Sparse Precision Matrix Estimation by ?1-Penalization.
Motivated by the analysis of genetical genomic data, we consider the problem of estimating high-dimensional sparse precision matrix adjusting for possibly a large number of covariates, where the covariates can affect the mean value of the random vector. We develop a two-stage estimation procedure to first identify the relevant covariates that affect the means by a joint ?1 penalization. The estimated regression coefficients are then used to estimate the mean values in a multivariate sub-Gaussian model in order to estimate the sparse precision matrix through a ?1-penalized log-determinant Bregman divergence. Under the multivariate normal assumption, the precision matrix has the interpretation of a conditional Gaussian graphical model. We show that under some regularity conditions, the estimates of the regression coefficients are consistent in element-wise ?? norm, Frobenius norm and also spectral norm even when p ? n and q ? n. We also show that with probability converging to one, the estimate of the precision matrix correctly specifies the zero pattern of the true precision matrix. We illustrate our theoretical results via simulations and demonstrate that the method can lead to improved estimate of the precision matrix. We apply the method to an analysis of a yeast genetical genomic data. PMID:23687392
Yin, Jianxin; Li, Hongzhe
SOPHIE+: First results of an octagonal-section fiber for high-precision radial velocity measurements
NASA Astrophysics Data System (ADS)
High-precision spectrographs play a key role in exoplanet searches and Doppler asteroseismology using the radial velocity technique. The 1 m s-1level of precision requires very high stability and uniformity of the illumination of the spectrograph. In fiber-fed spectrographs such as SOPHIE, the fiber-link scrambling properties are one of the main conditions for high precision. To significantly improve the radial velocity precision of the SOPHIE spectrograph, which was limited to 5-6 m s-1, we implemented a piece of octagonal-section fiber in the fiber link. We present here the scientific validation of the upgrade of this instrument, demonstrating a real improvement. The upgraded instrument, renamed SOPHIE+, reaches radial velocity precision in the range of 1-2 m s-1. It is now fully efficient for the detection of low-mass exoplanets down to 5-10 M? and for the identification of acoustic modes down to a few tens of cm s-1.
Bouchy, F.; DĒaz, R. F.; Hķbrard, G.; Arnold, L.; Boisse, I.; Delfosse, X.; Perruchot, S.; Santerne, A.
High precision measurement of the proton charge radius: The PRad experiment
The recent high precision measurements of the proton charge radius performed at PSI from muonic hydrogen Lamb shift puzzled the hadronic physics community. A value of 0.8418 {+-} 0.0007 fm was extracted which is 7{sigma} smaller than the previous determinations obtained from electron-proton scattering experiments and based on precision spectroscopy of electronic hydrogen. An additional extraction of the proton charge radius from electron scattering at Mainz is also in good agreement with these "electronic" determinations. An independent measurement of the proton charge radius from unpolarized elastic ep scattering using a magnetic spectrometer free method was proposed and fully approved at Jefferson Laboratory in June 2012. This novel technique uses the high precision calorimeter HyCal and a windowless hydrogen gas target which makes possible the extraction of the charge radius at very forward angles and thus very low momentum transfer Q{sup 2} up to 10{sup -4} (GeV/c){sup 2} with an unprecedented sub-percent precision for this type of experiment. In this paper, after a review of the recent progress on the proton charge radius extraction and the new high precision experiment PRad will be presented.
Meziane, Mehdi [DUKE
A high precision attitude determination and control system for the UYS-1 nanosatellite
NASA Astrophysics Data System (ADS)
This paper presents the design of a high precision attitude determination and control system for the UYS-1 Ukrainian nanosatellite. Its main task is the 3-axis stabilization with less than 0.5░ angle errors, so the satellite may take high precision photos of Earth's surface. To accomplish this task, this system comprises a star tracker and three reaction wheels. To avoid external disturbances and actuators faults, a PD-type and a PID-type robust controllers are simulated and the results are compared to an empirically adjusted PD controller.
Chaurais, J. R.; Ferreira, H. C.; Ishihara, J. Y.; Borges, R. A.; Kulabukhov, A. M.; Larin, V. A.; Belikov, V. V.
Fabrication and Assembly of High-Precision Hinge and Latch Joints for Deployable Optical Instruments
NASA Technical Reports Server (NTRS)
Descriptions are presented of high-precision hinge and latch joints that have been co-developed, for application to deployable optical instruments, by NASA Langley Research Center and Nyma/ADF. Page-sized versions of engineering drawings are included in two appendices to describe all mechanical components of both joints. Procedures for assembling the mechanical components of both joints are also presented. The information herein is intended to facilitate the fabrication and assembly of the high-precision hinge and latch joints, and enable the incorporation of these joints into the design of deployable optical instrument systems.
Phelps, James E.
A simple breathing circuit allowing precise control of inspiratory gases for experimental respiratory manipulations
Background Respiratory manipulations modulating blood flow and oxygenation levels have become an important component of modern functional MRI applications. Manipulations often consist of temporarily switching inspired fractions of CO2 and O2; and have typically been performed using simple oxygen masks intended for applications in respiratory therapy. However, precise control of inspired gas composition is difficult using this type of mask due to entrainment of room air and resultant dilution of inspired gases. We aimed at developing a gas delivery apparatus allowing improved control over the fractional concentration of inspired gases, to be used in brain fMRI studies. Findings The breathing circuit we have conceived allowed well controlled step changes in FiO2 and FiCO2, at moderate flow rates achievable on standard clinical flow regulators. In a two run test inside the scanner we demonstrate that tightly controlled simple gas switching manipulations can afford good intra-subject reproducibility of induced hyperoxia/hypercapnia responses. Although our approach requires a non-vented mask fitting closely to the subjectÆs face, the circuit ensures a continuous supply of breathable air even if the supply of medical gases is interrupted, and is easily removable in case of an emergency. The apparatus we propose is also compact and MRI compatible, allowing subject placement in confined spaces such as an MRI scanner for brain examinations. Conclusions We have reported a new approach for the controlled administration of medical gases, and describe an implementation of the breathing circuit that is MRI compatible and uses commercially available parts. The resultant apparatus allows simple, safe and precise manipulations of FiO2 and FiCO2.
High precision metrology method for unobscured Three Mirror Anastigmatic (TMA) mapping camera boresight
NASA Astrophysics Data System (ADS)
High precision of mapping camera boresight directly affects the positioning accuracy of geographical location and photogrammetry. Although it can fulfill the request of good performance for unobscured TMA optical system, which adopted computer aided alignment method, single lens was unobscured which unable ascertain boresight by using lens centering technology, and boresight is randomicity as a result of compensating relation of multivariables. A novel method using the measurement of theodolite space intersection was proposed to rapidly and high accurately complete establish the relation between boresight and a cube in precision alignment stage, simultaneously, the relation of component deflexion and boresight have been simulated by computer model reverse optimization. Thus, the image quality and precision of boresight was effective operated according to the request of satellite assembly.
Zhao, Xi-ting; Jiao, Wen-chun; Liao, Zhi-bo
High-precision absolute distance and vibration measurement with frequency scanned interferometry
We report high-precision absolute distance and vibration measurements performed with frequency scanned interferometry using a pair of single-mode optical fibers. Absolute distance was determined by counting the interference fringes produced while scanning the laser frequency. A high-finesse Fabry-Perot interferometer was used to determine frequency changes during scanning. Two multiple-distance-measurement analysis techniques were developed to improve distance precision and to extract the amplitude and frequency of vibrations. Under laboratory conditions, measurement precision of {approx}50 nm was achieved for absolute distances ranging from 0.1 to 0.7 m by use of the first multiple-distance-measurement technique. The second analysis technique has the capability to measure vibration frequencies ranging from 0.1 to 100 Hz with an amplitude as small as a few nanometers without a priori knowledge.
Yang, H.-J.; Deibel, Jason; Nyberg, Sven; Riles, Keith
Development of laser-based application system with high precision and speed
NASA Astrophysics Data System (ADS)
Recently, PCB(Printed Circuit Board) is required more high precision, function and miniaturization for advanced electronics, display, semiconductor and packaging, etc. and this complex PCB needs cutting, repair, trimming and structuring, etc. So, we make complex machine that is possible this all PCB processing and test PCB material processing using developed machine. This machine consists of UV nano-second pulse laser, power controller(self-developments), probe stage for trimming, auto focusing and scanner. The power controller is possible to monitor real-time power and adjust precision laser power. Using various parameters such as laser power, scanning speed, repetition rate and pulsed overlaps can obtain for process result having high precision and speed.
Ryu, Kwang-Hyun; Shin, Suk-Hoon; Park, Hyeong-Chan; Hwang, Tae-Sang
Conditions and methods of high-precision measurement of blood glucose concentration using mid-IR ATR spectroscopy
NASA Astrophysics Data System (ADS)
This paper involves conditions and methods of high precision measurement of blood glucose concentration using Mid-IR ATR spectroscopy: (1) Comparing the spectra of saline solution, plasma, and whole blood to which adding glucose respectively, we find that in these three backgrounds with different complexity, the absorption peaks of glucose are at the same wavelengths in the band of 1200 to 900 cm-1. (2) Analyzing experimental results of concentration gradient built by adding glucose to a series of plasma, we obtained a high correlation (greater than 0.98) between glucose concentration and absorbance in the band of 1200 to 900 cm-1, it provides us the feasibility of building calibration model of glucose concentration in this specific band. (3) In the process of building calibration model for glucose concentration of 40 whole blood samples (blood glucose concentration varied from 73 to 167 mg/dL, mean was 94.46 mg/dL, standard error was 17.68 mg/dL) by utilizing PLS method optimized with full cross validation, we applied genetic algorithms to the selection of optical subsets of wavelengths, the number of wavelengths for calibration was decreased to 14 and the precision of the model was improved considerably, RMSEP was 10.56 mg/dL. This proves that high precision measurement of blood glucose concentration can be achieved in narrow-band width (1200-900cm-1) when few wavelengths are selected.
Qin, Jianwei; Zhou, Dingwen; Zhang, Lu; Lei, Zhenlin; Xu, Kexin
Capability study for ozone high-precision retrieval with JEM/SMILES
NASA Astrophysics Data System (ADS)
One of the most unique characteristics of JEM/SMILES observation is its high sensitivity (500K system noise by employing 4K cooled SIS mixer) in detecting atmospheric limb emission in the submillimeter wave range, which are band A (624.3-625.5 GHz), band B (625.1-626.3 GHz), and band C (649.1-650.3 GHz). It observes limb emission from atmospheric minor constituents in the stratosphere, such as O3 , ClO, HCl, HNO3 , HOCl, CH3 CN, HO2 , BrO, O3 isotopes etc. The JEM/SMILES mission is mainly devoted to studying precise halogen chemistry related to ozone destruction. Spatial coverage is near global, that is the nominal latitude coverage is 38S - 65N owing to tilting the antenna beam to 45 degree left from the direction of orbital motion. It is highly expected that SMILES observation path encounters the atmosphere in the elongated polar voltex toward lower latitude in the northern hemisphere. The sensitivity of SMILES can be utilized for its unique observations, one is the detection of trace species which has never been observed in acceptable precision, and the other is high precision observation of major species such as O3 and HCl. This paper discusses how the ozone high-precision retrieval with the JEM/SMILES can be achieved based on the operational retrieval algorithm. The JEM/SMILES observes ozone absorption line at 625.37GHz in lower observation bands, band A and band B. As the JEM/SMILES is a high sensitive sensor, the high-precision retrieval is expected, the minimum precision of retrieved ozone height profile is 0.5% at about 30km under ideal condition, which is better than existing similar sensors, such as Aura/MLS and Odin/SMR. It is also discussed height resolutions (3.5-4.1 km nominally determined by the instrument) as trade off with precision. Thus these two factors should be decided by a kind of trade-off considering scientific requirements. The information content is used to optimize these factors and we clarify the precision, the height resolution, and height range of ozone retrieved height profile.
Takahashi, Chikako; Suzuki, Makoto; Ochiai, Satoshi; Takayanagi, Masahiro
The analysis of high pressure experimental data
NASA Technical Reports Server (NTRS)
This letter is concerned with the analysis of high pressure experimental data. It is demonstrated that ln H plots based on the Vinet et al. (1988) universal equation of state are a simple sensitive means for identifying anomalous P-V data in high pressure experiments and for detecting structural and phase transitions in solids subjected to high pressure.
Schlosser, Herbert; Ferrante, John
A high precision 24GHz FMCW radar based on a fractional-N ramp-PLL
A 24-GHz FMCW radar system is presented using a fractional-N phase-locked loop ramp generator. This fractional-N ramp generator achieves relative ramp nonlinearities below 10-8. Among others linear frequency ramps are important tools in high precision FMCW radar systems. Highly linear frequency ramps make post measurement error correction feasible. Other important aspects of the high performance FMCW radar system are the
Thomas Musch
Patch-sweeping with robust prior for high precision depth estimation in real-time systems
This paper presents a novel real-time approach for robust high precision and high quality depth estimation. It extends recent work on real-time Patch-Sweeping by combining the advantages of a robust hybrid stereo-based disparity estimator with the high accuracy of the Patch-Sweeping approach. It overcomes limitations of the existing Patch-Sweep approach, such as limited search range. Further, it implicitly benefits from
Wolfgang Waizenegger; Nicole Atzpadin; Oliver Schreer; Ingo Feldmann
High precision range extenders for an AC calibrator up to 600 V and 100 A
High precision range extenders for high voltage (600 V) and large current (100 A) have been developed,as separate units to be used with a previously developed National Research Council (NRC) ac calibrator. To obtain high accuracy and stable operation an error feed- forward technique was implemented. A current-comparator-based current transformer test set was used for checking the error of the
Petar N. Miljanic; David J. Angelo
Precision freehand sculpting for unicondylar knee replacement: design and experimental validation.
Precision freehand sculpting (PFS), is a hand-held semi-active robotic technology for bone shaping that works within the surgical navigation framework. PFS can alternate between two control modes - one based on control of exposure of the cutting bur and another based on the control of the speed of the cutting bur. In this study we evaluate the performance of PFS in preparing the femoral bone surface for unicondylar knee replacement (UKR). The experiment is designed to prepare a synthetic bone for UKR. The implant was a modified commercial design that allows accurate measurement of the implant position after it is placed on the prepared bone surface. The distal and anterior-distal facets were cut with a 5 mm cylindrical bur using exposure control. The posterior facet and the post holes were cut using a 6-mm spherical bur using speed control. Three users cut five specimens each. The performance was evaluated in terms of the implant fit and the performance time. The average cut times for the first two cuts combined were 4:35 min, and for the posterior cut 3:26 min. The average distance from the planned implant position was 0.54 mm (SD 0.23 mm) and the average angular difference was 1.08░ (SD 0.53░). PMID:22868782
Jaramaz, Branislav; Nikou, Constantinos
Experimental Characterization of Hysteresis in a Revolute Joint for Precision Deployable Structures
NASA Technical Reports Server (NTRS)
Recent studies of the micro-dynamic behavior of a deployable telescope metering truss have identified instabilities in the equilibrium shape of the truss in response to low-energy dynamic loading. Analyses indicate that these micro-dynamic instabilities arise from stick-slip friction within the truss joints (e.g., hinges and latches). The present study characterizes the low-magnitude quasi-static load cycle response of the precision revolute joints incorporated in the deployable telescope metering truss, and specifically, the hysteretic response of these joints caused by stick-slip friction within the joint. Detailed descriptions are presented of the test setup and data reduction algorithms, including discussions of data-error sources and data-filtering techniques. Test results are presented from thirteen specimens, and the effects of joint preload and manufacturing tolerances are investigated. Using a simplified model of stick-slip friction, a relationship is made between joint load-cycle behavior and micro-dynamic dimensional instabilities in the deployable telescope metering truss.
Lake, Mark S.; Fung, Jimmy; Gloss, Kevin; Liechty, Derek S.
Precise and cheap experimental setup for fast measurements of piezoelectric properties of crystals
NASA Astrophysics Data System (ADS)
A series impedance method [Mason and Fair, Proc. IRE, 464 (1942); IEEE Standard on Piezoelectricity ANSI/IEEE Std 176-1987 (New York: The Institute of Electrical and Electronics Engeneers, 1987)] is the most popular way for investigation of piezoelectric properties of crystals. The AC voltage generated by a vibrating crystal achieves its maximum if a frequency of an exciting signal applied to the sample is equal to a resonance frequency of the sample. In this article a very simple experimental setup for piezoelectric measurements was described. Usually measurements of resonance frequencies are made at a constant temperature, which makes an experiment long-lasting. The experimental setup described below allows performance of the experiment in slow-change temperature regime.
Wiesner, M.
FPC: A High-Speed Compressor for Double-Precision Floating-Point Data
Many scientific programs exchange large quantities of double-precision data between processing nodes and with mass storage devices. Data compression can reduce the number of bytes that need to be transferred and stored. However, data compression is only likely to be employed in high-end computing environments if it does not impede the throughput. This paper describes and evaluates FPC, a fast
Martin Burtscher; Paruj Ratanaworabhan
The Management of a High Precision Standards Laboratory for Energy Measurement
Since 1995, the Standards Laboratory of The Hongkong Electric Co., Ltd. (HEC) has been accredited by the Hong Kong Laboratory Accreditation Scheme (HOKLAS) and became the first accredited laboratory for electrical energy measurement in Hong Kong. Its major function is to establish measurement traceability through high precision electrical standards in the laboratory to electricity meters installed at the customer's premises.
H. C. Poan
Researchers of NASA's GSFC are currently developing a scanning airborne photon-counting laser altimeter. This paper summarizes the creation of high resolution, precise DEMs from repeat passes of airborne laser scanning surveys to validate this new system. To study coastal erosion several sections of the Atlantic and Pacific coast have been mapped by NASA's Airborne Topographic Mapper (ATM) conical scanning altimeter.
Bea Csatho; Young-Ran Lee; Tony Schenk; William Krabill; Jan McGarry
P2-33: Numerical issues in high precision charged particle optics
This work addresses methods to assess the aggregate accuracy and computational costs of numerical techniques in charged particle optics (CPO) simulation. Numerical issues are examined in the areas of accurate field computation and high precision trajectory integration. Improved algorithms will be presented. An approach to determine the accuracy and computational costs of combined field and integration techniques will be presented.
Robert H. Jackson
High-Precision Contouring Control of Table Drive System in Machine Tools Using Lost Motion Compensation
This paper presents a novel compensation methodology for nonlinearities in table drive system of machine tools, providing the high-precision contouring control. The nonlinearities in a target system are mainly composed of the lost motion between motor and table and the nonlinear friction on the table sliding surface with standard lubricants. In the research, the lost motion is especially modeled as
Makoto Iwasaki; Masashi Miyaji; Nobuyuki Matsui
High-precision control of a maglev linear actuator with nanopositioning capability
Presents high-precision control of a magnetically levitated (maglev) linear actuator with novel geometric configuration. The linear actuator is used as a unit actuator in the development of a maglev instrument with six-axis nanopositioning capability. The novel configuration in this design concept leads to a lightweight and compact size. The objective of development of this maglev linear actuator is to verify
Won-jong Kim; Himanshu Maheshwari
Diode Laser-based Sensor for High Precision Measurements of Ambient CO2
We report on the development of a new, high precision sensor for monitoring ambient CO2. This economical, robust, autonomous CO2 sensor is intended for widespread deployment in networks. We have developed a tunable diode laser-based absorption spectrometer, operating at a wavelength of 2 \\
D. M. Sonnenfroh; K. Parameswaran; R. Varner
High-precision two-colour spaceborne laser ranging system for monitoring of geodynamic processes
The design concept of a spaceborne two-color picosecond-pulse laser ranging system operating at a pulse rate of about 20 Hz from a 1600 km circular orbit is presented. The system is designed to estimate distances to ground-based passive arrays of retroreflector targets, which are deployed in tectonically highly active zones, with a precision within + or - 1 cm. Since
H. P. Lutz; W. Krause; G. Barthel
Satellite navigation for high precision aircraft navigation with emphasis on atmospheric effects
Investigations into very high precise aircraft position determination with the Global Positioning System are presented. After a short introduction into the GPS code and carrier wave observables, the approach for carrier phase ambiguity resolution with single frequency L1 measurements in a kinematic environment is discussed. Flight test results are given to demonstrate the centimeter accuracy achievable in position using pure
B. Tiemeyer; M. E. Cannon; G. Lachapelle; G. Schanzer
MRPC-PET: A new technique for high precision time and position measurements
The purpose of this paper is to consider a new technology for medical diagnosis: the MRPC-PET. This technology allows excellent time resolution together with 2-D position information thus providing a fundamental step in this field. The principle of this method is based on the Multigap Resistive Plate Chamber (MRPC) capable of high precision time measurements. We have previously found that
K. Doroud; D. Hatzifotiadou; S. Li; M. C. S. Williams; A. Zichichi; R. Zuyeuski
Total dose radiation effect simulations on a high-precision data acquisition system
A novel method to evaluate total dose radiation response on large mixed signal circuits is described. The method is based on partly behavioral, partly structural simulation on the VHDL-AMS language. Results obtained with the developed simulation method are compared to total dose testing results of an embedded high-precision data acquisition system. The system was total dose tested until functional failure
Esko Mikkola; Bert Vermeire; Terence Chiu; Hugh Barnaby; H. G. Parks
High precision semiautomated computed tomography measurement of lumbar disk and vertebral heights
Purpose: Evaluation of treatments of many spine disorders requires precise measurement of the heights of vertebral bodies and disk spaces. The authors present a semiautomated computer algorithm measuring those heights from spine computed tomography (CT) scans and evaluate its precision. Methods: Eight patients underwent two spine CT scans in the same day. In each scan, five thoracolumbar vertebral heights and four disk heights were estimated using the algorithm. To assess precision, the authors computed the differences between the height measurements in the two scans, coefficients of variation (CV), and 95% limits of agreement. Intraoperator and interoperator precisions were evaluated. For local vertebral and disk height measurement (anterior, middle, posterior) the algorithm was compared to a manual mid-sagittal plane method. Results: The mean (standard deviation) interscan difference was as low as 0.043 (0.031) mm for disk heights and 0.044 (0.043) mm for vertebral heights. The corresponding 95% limits of agreement were [?0.085, 0.11] and [?0.10, 0.12] mm, respectively. Intraoperator and interoperator precision was high, with a maximal CV of 0.30%. For local vertebral and disk heights, the algorithm improved upon the precision of the manual mid-sagittal plane measurement by as much as a factor of 6 and 4, respectively. Conclusions: The authors evaluated the precision of a novel computer algorithm for measuring vertebral body heights and disk heights using short term repeat CT scans of patients. The 95% limits of agreement indicate that the algorithm can detect small height changes of the order of 0.1 mm.
Tan, Sovira; Yao, Jianhua; Yao, Lawrence; Ward, Michael M.
High-power and high-brightness solid state laser systems for precise and fast micromachining
NASA Astrophysics Data System (ADS)
To meet the industry's demand for reducing machine cycle lengths concerning laser-drilling a laser was developed at the LMTB-laboratories that emits high-power peak-pulses at excellent beam-quality. In co-operation with Technical University of Berlin (TU Berlin) a Nd:YAG Master-Oscillator Power-Amplifier (MOPA) laser system is undergoing permanent enhancements aiming at shorter pulse duration, higher fluence and improved long-term stability. Presently, the output power of the oscillator (10W@1064nm) with a beam-quality of M2=1.3 is amplified to more than 100W@1064nm with M2=2.3 and a single pulse energy up to 800 mJ. The pulse duration can be varied between 31 and 230ns. On account of the excellent beam quality, frequency conversion was carried out down to 266nm. The MOPA-System was used for laser micro scribing and drilling experiments into metals and ceramics where the influence of the beam quality on the geometrical shape of the hole is investigated and compared with applications conducted with similar laser systems. Additionally means in optimizing the drilling process such as burr-minimizing and melt-reduction were introduced. Furthermore, experiments using tapered drilling technique are undertaken. A maximum aspect ratio of 1:180 in sapphire was obtained. We achieved high ablation rates and precise structures in Al2O3 (ceramic and sapphire), AlN, ZrO2, Ni-base alloy, platinum, tungsten and many more materials. Further improvement of the system was undertaken by means of multimode fibers as phase conjugate mirrors (PCM) using the effect of stimulated brillouin scattering (SBS).
Binder, Alexander; Jaber, Houssam; Ashkenasi, David; Riesbeck, Thomas; Eichler, Hans-J.
High-precision Penning trap mass measurements for tests of the Standard Model
With the nowadays achievable accuracy in Penning trap mass spectrometry on short-lived exotic nuclides as well as stable atoms, precision fundamental tests can be performed, among them a test of the Standard Model, in particular with regard to the weak interaction, the CPT symmetry conservation, and the unitarity of the Cabibbo-Kobayashi-Maskawa quark mixing matrix. In addition, accurate mass values of specific nuclides are important for neutrino physics. The presently best tests of the Standard Model with high-precision Penning trap mass spectrometry will be reviewed.
Blaum, Klaus; Eliseev, Sergey [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Nagy, Szilard [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt (Germany)
Generalized lock-in amplifier for precision measurement of high frequency signals.
We herein formulate the concept of a generalized lock-in amplifier for the precision measurement of high frequency signals based on digital cavities. Accurate measurement of signals higher than 200 MHz using the generalized lock-in is demonstrated. The technique is compared with a traditional lock-in and its advantages and limitations are discussed. We also briefly point out how the generalized lock-in can be used for precision measurement of giga-hertz signals by using parallel processing of the digitized signals. PMID:24289431
Fu, Siyuan; Sakurai, Atsunori; Liu, Liang; Edman, Fredrik; Pullerits, T§nu; ųwall, Viktor; Karki, Khadga Jung
High-precision measurements of the diamond Hugoniot in and above the melt region
High-precision measurements of the diamond principal Hugoniot have been made at pressures between 6 and 19 Mbar. Shock velocities were determined with 0.3%-1.1% precision using a velocity interferometer. Impedance-matching analysis, incorporating systematic uncertainties in the equation of state of the quartz standard, was used to determine the Hugoniot with 1.2%-2.7% precision in density. The results are in good agreement with published ab initio calculations, which predict a small negative melt slope along the Hugoniot, but disagree with previous laser-driven shock wave experiments, which had observed a large density increase in the melt region. In the extensive solid-liquid coexistence regime between 6 and 10 Mbar, the present measurements indicate that the mixed phase is a few percent more dense than what would be expected from a simple interpolation between liquid and solid Hugoniots.
Hicks, D. G.; Celliers, P. M.; Bradley, D. K.; Eggert, J. H.; Collins, G. W. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Boehly, T. R. [Laboratory for Laser Energetics, University of Rochester, New York 14623 (United States); McWilliams, R. S. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); University of California, Berkeley, California 94720 (United States); Jeanloz, R. [University of California, Berkeley, California 94720 (United States)
High precision measurements of the diamond Hugoniot in and above the melt region
High precision laser-driven shock wave measurements of the diamond principal Hugoniot have been made at pressures between 6 and 19 Mbar. Shock velocities were determined with 0.3-1.1% precision using a velocity interferometer. Impedance matching analysis, incorporating systematic errors in the equation-of-state of the quartz standard, was used to determine the Hugoniot with 1.2-2.7% precision in density. The results are in good agreement with published ab initio calculations which predict a small negative melt slope along the Hugoniot, but disagree with previous laser-driven shock wave experiments which had observed a large density increase in the melt region. In the extensive solid-liquid coexistence regime between 6 and 10 Mbar these measurements indicate that the mixed phase may be slightly more dense than would be expected from a simple interpolation between liquid and solid Hugoniots.
Hicks, D; Boehly, T; Celliers, P; Bradley, D; Eggert, J; McWilliams, R S; Collins, G
High precision measurement of the superallowed 0+ --> 0+ beta decay of 22Mg.
The half-life, 3.8755(12) s, and superallowed branching ratio, 0.5315(12), for 22Mg beta decay have been measured with high precision. The latter depended on gamma-ray intensities being measured with an HPGe detector calibrated for relative efficiencies to an unprecedented 0.15%. Previous precise measurements of 0+ --> 0+ transitions have been restricted to the nine that populate stable daughter nuclei. No more such cases exist, and any improvement in a critical Cabibbo-Kobayashi-Maskawa unitarity test must depend on precise measurements of more exotic nuclei. With this branching-ratio measurement, we show those to be possible for T(z)=-1 parents. We obtain a corrected Ft value of 3071(9) s, in good agreement with expectations. PMID:14525235
Hardy, J C; Iacob, V E; Sanchez-Vega, M; Neilson, R G; Azhari, A; Gagliardi, C A; Mayes, V E; Tang, X; Trache, L; Tribble, R E
Accurate and emergent applications for high precision light small aerial remote sensing system
NASA Astrophysics Data System (ADS)
In this paper, we focus on the successful applications of accurate and emergent surveying and mapping for high precision light small aerial remote sensing system. First, the remote sensing system structure and three integrated operation modes will be introduced. It can be combined to three operation modes depending on the application requirements. Second, we describe the preliminary results of a precision validation method for POS direct orientation in 1:500 mapping. Third, it presents two fast response mapping products- regional continuous three-dimensional model and digital surface model, taking the efficiency and accuracy evaluation of the two products as an important point. The precision of both products meets the 1:2 000 topographic map accuracy specifications in Pingdingshan area. In the end, conclusions and future work are summarized.
Pei, Liu; Yingcheng, Li; Yanli, Xue; Qingwu, Hu; Xiaofeng, Sun
A new method to eliminate the noise of vacuum microelectronic high precision accelerometer
NASA Astrophysics Data System (ADS)
The vacuum microelectronic high precision accelerometer was developed based on the vacuum field emission theory; it has many advantages such as high precision, good linearity in theory, but the inherent low frequency such as 1/f noise of the accelerometer decreases the signal-to-noise ratio greatly, and it is the main influencing factors to precision and linearity of accelerometer. In this paper a new method to eliminate noise of vacuum microelectronic high precision accelerometer was first bring forward by using modulation and demodulation and coherent detection technology. The system mainly includes AC signal generator, current obtain, phase shift, demodulator, differential amplification and feedback control. At last, the noise between 0 Hz and 200Hz contrast test experiment of the accelerometer was carried out by oscilloscope, the result shows the mean spectrum density of output signal is 29?V/?Hz between 0 Hz and 200Hz. Static gravitation field rolling experiment in +/-1 g is also performed to measure the linearity of the accelerometer; the least-square linear fitting curve shows the maximum nonlinear is 0.41%. Through the results we can draw conclusion that the noise and linear performs have been greatly improved through eliminated noise.
Liu, Hai-Tao; Wen, Zhi-Yu; Chen, Li; Wen, Zhong-Quan; He, Xue-Feng
A High Precision 24 GHz FMCW-Radar using a Phase-Slope Signal Processing Algorithm
A 24 GHz FMCW-radar system is presented using a phase-slope algorithm for increased range determination accuracy. Additionally a fractional-N ramp generator provides a highly linear frequency ramp with nonlinearities below 10┐8. These highly linear frequency ramps make post measurement error correction feasible. Especially analysing the phase-slope of the i.f. signal results in an increased measurement precision compared to the standard
T. Musch
Experimental verification of distributed piezoelectric actuators for use in precision space structures
NASA Technical Reports Server (NTRS)
An analytic model for structures with distributed piezoelectric actuators is experimentally verified for the cases of both surface-bonded and embedded actuators. A technique for the selection of such piezoelectric actuators' location has been developed, and is noted to indicate that segmented actuators are always more effective than continuous ones, since the output of each can be individually controlled. Manufacturing techniques for the bonding or embedding of segmented piezoelectric actuators are also developed which allow independent electrical contact to be made with each actuator. Static tests have been conducted to determine how the elastic properties of the composite are affected by the presence of an embedded actuator, for the case of glass/epoxy laminates.
Crawley, E. F.; De Luis, J.
High precision alignment of cryo-electron subtomograms through gradient-based parallel optimization
Background Cryo-electron tomography emerges as an important component for structural system biology. It not only allows the structural characterization of macromolecular complexes, but also the detection of their cellular localizations in near living conditions. However, the method is hampered by low resolution, missing data and low signal-to-noise ratio (SNR). To overcome some of these difficulties and enhance the nominal resolution one can align and average a large set of subtomograms. Existing methods for obtaining the optimal alignments are mostly based on an exhaustive scanning of all but discrete relative rigid transformations (i.e. rotations and translations) of one subtomogram with respect to the other. Results In this paper, we propose gradient-guided alignment methods based on two popular subtomogram similarity measures, a real space as well as a Fourier-space constrained score. We also propose a stochastic parallel refinement method that increases significantly the efficiency for the simultaneous refinement of a set of alignment candidates. We estimate that our stochastic parallel refinement is on average about 20 to 40 fold faster in comparison to the standard independent refinement approach. Results on simulated data of model complexes and experimental structures of protein complexes show that even for highly distorted subtomograms and with only a small number of very sparsely distributed initial alignment seeds, our combined methods can accurately recover true transformations with a substantially higher precision than the scanning based alignment methods. Conclusions Our methods increase significantly the efficiency and accuracy for subtomogram alignments, which is a key factor for the systematic classification of macromolecular complexes in cryo-electron tomograms of whole cells.
High-Precision U-Pb Zircon Dates as Benchmarks in Absolute Time
NASA Astrophysics Data System (ADS)
High-precision IDTIMS U-Pb zircon dates provide the most precise and accurate isotopic benchmarks in absolute time, due to the concordancy check of the paired U-Pb decay schemes, the precisely measured 235U and 238U decay constants, very high initial parent/daughter ratios, and the robust nature of zircon to loss or gain of U and Pb over geologic time. However, caveats to the use of such zircon dates include the accurate assessment and minimization of random and systematic errors in the analytical methods, and decay constant uncertainties. Unfortunately, there exists little consensus within the U-Pb geochronological community regarding an international zircon standard for the external assessment of interlaboratory reproducibility, while residual questions remain regarding the potential for systematic error in the single available high-precision counting experiment of the U decay constants1. Stringent criteria are imposed on candidates for zircon geochronology standards including the absence of inheritance and Pb-loss at both the single grain scale and the resolution of microbeam techniques. We present an example of the potential and limitations of a possible zircon standard, AS3, from the Duluth Complex, North American Midcontinent Rift2. New data for 27 single zircons are indistinguishable from prior results, with 207Pb/206Pb and upper intercept dates identical within error to a U-Pb concordia date of 1099.1+/-0.2 Ma (+/-1.2 Ma with systematic errors) based on 12 concordant and equivalent analyses. However, we must reiterate that a zircon population exhibiting consistent concordancy remains elusive, as AS3 and all Paleozoic and older standard candidates so far examined contain grains exhibiting Pb-loss, although rigorous selection and preparation of zircons through diamagnetic separation and aggressive abrasion can mitigate this phenomenon. The continued screening of candidate standards by both IDTIMS and SHRIMP techniques should be an organized, international endeavor involving all high-precision geochronology laboratories. Under the single assumption that the equivalent data represent the approach to closed system behavior, the correspondence of the AS3 zircons with the presently defined concordia curve suggests the accuracy of the ratio of the presently accepted decay constants1 to within their 0.1% (2? ) counting errors. While a proposed revision of the 235U decay constant3 is apparently unnecessary, additional high-precision, high n, statistically equivalent zircon population samplings are necessary to further evaluate decay constants and their uncertainties at the per mil level. When measured on appropriate lithologies, high-precision U-Pb dates also become powerful tools for the intercalibration of other radioisotope decay rates more difficult to measure through counting or accumulation (e.g. 40K, 176Lu, 187Re). We will present several new high-precision data sets for quickly cooled Oligocene to Archean extrusive and intrusive rocks, and assess their usefulness as benchmarks for the intercalibration of radiometric time; a growing number of high-precision U-Pb zircon and 40Ar/39Ar feldspar, biotite or hornblende pairs spanning more than 3 Ga in absolute time indicate a consistently younger bias in 40Ar/39Ar dates of between 0.7 and 1%. 1Jaffey et al. (1974) Phys Rev C 4:1889-1906; 2Paces and Miller (1993) J Geophys Res 98:13997-14013; 3Mattinson (2000) EOS 81:S444
Schmitz, M. D.; Bowring, S. A.; Schoene, B.
Charge breeding rare isotopes for high precision mass measurements: challenges and opportunities
NASA Astrophysics Data System (ADS)
Ion charge breeding for Penning-trap mass spectrometry has been established as providing a precision increase that scales linearly with the charge state of the ion. Fast and efficient charge breeding is a precondition for the application of this approach to rare isotopes. However, in view of low yields and short half-lives the precision boost is partly compromised by unavoidable ion losses inherent to the charge breeding process. The mass spectrometer TRIUMFs ion trap for atomic and nuclear science is pioneering this field by coupling a Penning trap and an electron beam ion trap to the rare-isotope beam facility ISAC at TRIUMF. Here we present simulations that calculate and maximize the effective precision gain of time-of-flight ion-cyclotron-resonance measurements with highly charged ions of short-lived nuclides. In addition we compare the characteristics of measurements with singly and highly charged ions, and we summarize recent results that explored benefits of charge breeding that go beyond the precision increase.
Simon, M. C.; Macdonald, T. D.; Bale, J. C.; Chowdhury, U.; Eberhardt, B.; Eibach, M.; Gallant, A. T.; Jang, F.; Lennarz, A.; Luichtl, M.; Ma, T.; Robertson, D.; Simon, V. V.; Andreoiu, C.; Brodeur, M.; Brunner, T.; Chaudhuri, A.; Crespo L¾pez-Urrutia, J. R.; Delheij, P.; Ettenauer, S.; Frekers, D.; Grossheim, A.; Gwinner, G.; Kwiatkowski, A. A.; Lapierre, A.; Manķ, E.; Pearson, M. R.; Ringle, R.; Schultz, B. E.; Dilling, J.
High precision mobile location framework and its service based on virtual reference station of GPS
NASA Astrophysics Data System (ADS)
The wireless communication technology and space technology are synchronously developed in recent years, which bring up the development of location based service (LBS). At present, many location technology methods were developed. However, all these methods can only provide a relative poor location precision and depend on high cost. The technology of Virtual Reference Station (VRS) of GPS is then involved in this paper. One of the objective in this paper is aim to give the LBS position structure to improve the mobile location position when a mobile position instrument is connected with VRS network. The cheaper GPS built-in Personal Designer Aid (PDA) is then used to achieve a higher precision by using RTCM data from existing VRS network. In order to obtain a high precision position when using the low-cost GPS receiver as a rover, the infrusture of the mobile differential correction system is then put forward. According to network transportation of RTCM via internet protocol (NTRIP), the message is communicated through wireless network, such as GPRS, CDMA and so on. The rough coordinate information is sent to VRS control center continuously, and then the VRS correction information is replied to rover in the data format of RTCM3.1. So the position will be updated based on mathematic solution after the decoding of RTCM3.1 data. The thought of LBS position can improve the precision, and can speed the LBS.
Liu, Chun; Sun, Liangyu; Yao, Lianbi
High-precision predictions for the light CP-even Higgs boson mass of the minimal supersymmetric standard model.
For the interpretation of the signal discovered in the Higgs searches at the LHC it will be crucial in particular to discriminate between the minimal Higgs sector realized in the standard model (SM) and its most commonly studied extension, the minimal supersymmetric standard model (MSSM). The measured mass value, having already reached the level of a precision observable with an experimental accuracy of about 500 MeV, plays an important role in this context. In the MSSM the mass of the light CP-even Higgs boson, Mh, can directly be predicted from the other parameters of the model. The accuracy of this prediction should at least match the one of the experimental result. The relatively high mass value of about 126 GeV has led to many investigations where the scalar top quarks are in the multi-TeV range. We improve the prediction for Mh in the MSSM by combining the existing fixed-order result, comprising the full one-loop and leading and subleading two-loop corrections, with a resummation of the leading and subleading logarithmic contributions from the scalar top sector to all orders. In this way for the first time a high-precision prediction for the mass of the light CP-even Higgs boson in the MSSM is possible all the way up to the multi-TeV region of the relevant supersymmetric particles. The results are included in the code FEYNHIGGS. PMID:24765944
Hahn, T; Heinemeyer, S; Hollik, W; Rzehak, H; Weiglein, G
High-Precision Predictions for the Light CP-Even Higgs Boson Mass of the Minimal Supersymmetric Standard Model
NASA Astrophysics Data System (ADS)
For the interpretation of the signal discovered in the Higgs searches at the LHC it will be crucial in particular to discriminate between the minimal Higgs sector realized in the standard model (SM) and its most commonly studied extension, the minimal supersymmetric standard model (MSSM). The measured mass value, having already reached the level of a precision observable with an experimental accuracy of about 500 MeV, plays an important role in this context. In the MSSM the mass of the light CP-even Higgs boson, Mh, can directly be predicted from the other parameters of the model. The accuracy of this prediction should at least match the one of the experimental result. The relatively high mass value of about 126 GeV has led to many investigations where the scalar top quarks are in the multi-TeV range. We improve the prediction for Mh in the MSSM by combining the existing fixed-order result, comprising the full one-loop and leading and subleading two-loop corrections, with a resummation of the leading and subleading logarithmic contributions from the scalar top sector to all orders. In this way for the first time a high-precision prediction for the mass of the light CP-even Higgs boson in the MSSM is possible all the way up to the multi-TeV region of the relevant supersymmetric particles. The results are included in the code FeynHiggs.
Hahn, T.; Heinemeyer, S.; Hollik, W.; Rzehak, H.; Weiglein, G.
A near infrared laser frequency comb for high precision Doppler planet surveys
NASA Astrophysics Data System (ADS)
Perhaps the most exciting area of astronomical research today is the study of exoplanets and exoplanetary systems, engaging the imagination not just of the astronomical community, but of the general population. Astronomical instrumentation has matured to the level where it is possible to detect terrestrial planets orbiting distant stars via radial velocity (RV) measurements, with the most stable visible light spectrographs reporting RV results the order of 1 m/s. This, however, is an order of magnitude away from the precision needed to detect an Earth analog orbiting a star such as our sun, the Holy Grail of these efforts. By performing these observations in near infrared (NIR) there is the potential to simplify the search for distant terrestrial planets by studying cooler, less massive, much more numerous class M stars, with a tighter habitable zone and correspondingly larger RV signal. This NIR advantage is undone by the lack of a suitable high precision, high stability wavelength standard, limiting NIR RV measurements to tens or hundreds of m/s [1, 2]. With the improved spectroscopic precision provided by a laser frequency comb based wavelength reference producing a set of bright, densely and uniformly spaced lines, it will be possible to achieve up to two orders of magnitude improvement in RV precision, limited only by the precision and sensitivity of existing spectrographs, enabling the observation of Earth analogs through RV measurements. We discuss the laser frequency comb as an astronomical wavelength reference, and describe progress towards a near infrared laser frequency comb at the National Institute of Standards and Technology and at the University of Colorado where we are operating a laser frequency comb suitable for use with a high resolution H band astronomical spectrograph.
Osterman, S.; Diddams, S.; Quinlan, F.; Bally, J.; Ge, J.; Ycas, G.
A New High-precision Correction Method of Temperature Distribution in Model Stellar Atmospheres
NASA Astrophysics Data System (ADS)
The main features of the temperature correction methods, suggested and used in modeling of plane-parallel stellar atmospheres, are discussed. The main features of the new method are described. Derivation of the formulae for a version of the Uns÷ld-Lucy method, used by us in the SMART (Stellar Model Atmospheres and Radiative Transport) software for modeling stellar atmospheres, is presented. The method is based on a correction of the model temperature distribution based on minimizing differences of flux from its accepted constant value and on the requirement of the lack of its gradient, meaning that local source and sink terms of radiation must be equal. The final relative flux constancy obtainable by the method with the SMART code turned out to have the precision of the order of 0.5 %. Some of the rapidly converging iteration steps can be useful before starting the high-precision model correction. The corrections of both the flux value and of its gradient, like in Uns÷ld-Lucy method, are unavoidably needed to obtain high-precision flux constancy. A new temperature correction method to obtain high-precision flux constancy for plane-parallel LTE model stellar atmospheres is proposed and studied. The non-linear optimization is carried out by the least squares, in which the Levenberg-Marquardt correction method and thereafter additional correction by the Broyden iteration loop were applied. Small finite differences of temperature (? T/T=10-3) are used in the computations. A single Jacobian step appears to be mostly sufficient to get flux constancy of the order 10-2 %. The dual numbers and their generalization -- the dual complex numbers (the duplex numbers) -- enable automatically to get the derivatives in the nilpotent part of the dual numbers. A version of the SMART software is in the stage of refactorization to dual and duplex numbers, what enables to get rid of the finite differences, as an additional source of lowering precision of the computed results.
Sapar, A.; Poolamõe, R.; Sapar, L.
High Precision Tracking Control based on Pseudo-Inverse Feedforward Control System for Next-Generation Optical Disks
NASA Astrophysics Data System (ADS)
Optical disk drive systems must realize high-precision tracking control. For this purpose, we have already proposed a tracking control system that is composed of a high gain servo controller (HGSC) and a perfect tracking controller (PTC). The conventional feedforward tracking control system adequately suppresses the tracking error caused by track eccentricity. However, the PTC system in the conventional system is complicated. Therefore, the PTC system embedded on a digital signal processor (DSP) cannot realize fast sampling time and the conventional system has a speedup limitation in the optical disk tracking control system. Hence, in this paper, we propose a new high-speed and high-precision feedforward tracking control system that uses a pseudo-inverse matrix. The proposed system consists of the pseudo-inverse feedforward control (P-IFFC). The proposed system realizes simple and quick execution in a digital signal processor software servo. Our experimental results confirm that the proposed system effectively suppresses the tracking error under a condition of the 7200 rpm disk rotation speed of DVD+R. In addition, the conventional systems and the proposed system with a pseudo-inverse matrix are compared in terms of processing time and tracking error.
Ogata, Tokoku; Nakazaki, Tatsuya; Sakimura, Naohide; Ohishi, Kiyoshi; Miyazaki, Toshimasa; Koide, Daiichi; Tokumaru, Haruki; Takano, Yoshimichi
Direct high-precision measurement of the magnetic moment of the proton.
One of the fundamental properties of the proton is its magnetic moment, Ąp. So far Ąp has been measured only indirectly, by analysing the spectrum of an atomic hydrogen maser in a magnetic field. Here we report the direct high-precision measurement of the magnetic moment of a single proton using the double Penning-trap technique. We drive proton-spin quantum jumps by a magnetic radio-frequency field in a Penning trap with a homogeneous magnetic field. The induced spin transitions are detected in a second trap with a strong superimposed magnetic inhomogeneity. This enables the measurement of the spin-flip probability as a function of the drive frequency. In each measurement the proton's cyclotron frequency is used to determine the magnetic field of the trap. From the normalized resonance curve, we extract the particle's magnetic moment in terms of the nuclear magneton: ?p = 2.792847350(9)?N. This measurement outperforms previous Penning-trap measurements in terms of precision by a factor of about 760. It improves the precision of the forty-year-old indirect measurement, in which significant theoretical bound state corrections were required to obtain Ąp, by a factor of 3. By application of this method to the antiproton magnetic moment, the fractional precision of the recently reported value can be improved by a factor of at least 1,000. Combined with the present result, this will provide a stringent test of matter/antimatter symmetry with baryons. PMID:24870545
Mooser, A; Ulmer, S; Blaum, K; Franke, K; Kracke, H; Leiteritz, C; Quint, W; Rodegheri, C C; Smorra, C; Walz, J
Optical timing receiver for the NASA laser ranging system. Part 2: High precision time interval digitizer
NASA Technical Reports Server (NTRS)
The development of a high precision time interval digitizer is described. The time digitizer is a 10 psec resolution stop watch covering a range of up to 340 msec. The measured time interval is determined as a separation between leading edges of a pair of pulses applied externally to the start input and the stop input of the digitizer. Employing an interpolation techniques and a 50 MHz high precision master oscillator, the equivalent of a 100 GHz clock frequency standard is achieved. Absolute accuracy and stability of the digitizer are determined by the external 50 MHz master oscillator, which serves as a standard time marker. The start and stop pulses are fast 1 nsec rise time signals, according to the Nuclear Instrument means of tunnel diode discriminators. Firing level of the discriminator define start and stop points between which the time interval is digitized.
Leskovar, B.; Turko, B.
Using femtosecond laser to fabricate highly precise interior three-dimensional microstructures in polymeric flow chip
This paper reports using femtosecond laser marker to fabricate the three-dimensional interior microstructures in one closed flow channel of plastic substrate. Strip-like slots in the dimensions of 800 ?mū400 ?mū65 ?m were ablated with pulse Ti:sapphire laser at 800 nm (pulse duration of ?120 fs with 1 kHz repetition rate) on acrylic slide. After ablation, defocused beams were used to finish the surface of microstructures. Having finally polished with sonication, the laser fabricated structures are highly precise with the arithmetic roughness of 1.5 and 4.5 nm. Fabricating such highly precise microstructures cannot be accomplished with nanosecond laser marking or other mechanical drilling methods. In addition, since laser ablation can directly engrave interior microstructures in one closed chip, glue smearing problems to damage molded microstructures possibly to occur during the chip sealing procedures can be avoided too.
Lee, Chia-Yu; Chang, Ting-Chou; Wang, Shau-Chun; Chien, Chih-Wei; Cheng, Chung-Wei
Optical phasing of a segmented mirror with sub-nanometer precision: experimental results of the APE Internal Metrology
NASA Astrophysics Data System (ADS)
This paper presents a non-contact optical metrology measuring the pistons and tip/tilt angles of the 61 hexagonal segments of a compact-sized segmented mirror. The instrument has been developed within the scope of a design study for a European Extremely Large Telescope (E-ELT). It is used as reference sensor for cophasing of the mirror segments in closed loop control. The mirror shape is also measured by different types of stellar light-based phasing cameras whose performances will be evaluated with regard to a future E-ELT. Following a description of the system architecture, the second part of the paper presents experimental results demonstrating the level of precision: 0.48nm RMS in piston and 0.074 ?rad RMS in tip and tilt.
Wilhelm, Rainer; Luong, Bruno; Courteville, Alain; Estival, Sķbastien; Gontķ, Frķdķric
High precision Lu¢Hf geochronology of Eocene eclogite-facies rocks from Syros, Cyclades, Greece
Garnet-bearing high pressure, low temperature (HP\\/LT) metamorphic rocks of the Cycladic Blueschist Unit have been investigated by Lu¢Hf geochronology. Eclogites from Syros Island yield precise ages of 52.2▒0.3ĀMa, 51.4▒0.4ĀMa, and 50▒2ĀMa. Preserved major- and trace element growth zoning in garnet suggests that the closure temperature of the Lu¢Hf system in garnet was higher than the estimated peak metamorphic temperature of
Markus Lagos; Erik E. Scherer; Frank Tomaschek; Carsten M³nker; Mark Keiter; Jasper Berndt; Chris Ballhaus
High-performance speed control of electric machine using low-precision shaft encoder
For a high-performance servo drive system, it is important to estimate and control the motor speed precisely over a wide-speed range. Therefore, the disturbance-rejection ability and the robustness to variations of the mechanical parameters such as inertia should be considered. This paper shows that the adaptive state estimator and self-tuning regulator based on the recursive extended least squares (RELS) parameter
Taeg-Joon Kweon; Dong-Seok Hyun
Thermo-optic noise in coated mirrors for high-precision optical measurements
Thermal fluctuations in the coatings used to make high reflectors are becoming significant noise sources in precision optical measurements and are particularly relevant to advanced gravitational-wave detectors. There are two recognized sources of coating thermal noise; mechanical loss and thermal dissipation. Thermal dissipation causes thermal fluctuations in the coating which produce noise via the thermoelastic and thermorefractive mechanisms. We treat these mechanisms coherently, give a correction for finite coating thickness, and evaluate the implications for Advanced LIGO.
Evans, M.; Fritschel, P.; Harry, G. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Ballmer, S.; Ogin, G. [California Institute of Technology, Pasadena, California 91125 (United States); Fejer, M. [Stanford University, Stanford, California 94305 (United States)
Highly precise distributed Brillouin scattering sensor for structural health monitoring of optical ground wire cable
A distributed Brillouin scattering sensor with high special precision has been developed for the measurement of small damages\\/cracks of 1.5 cm. The out-layer damaged regions in an optical ground wire (OPGW) cable have been identified successfully by measuring the strain distributions every 5 cm using this technology. The stress increased to 127 kN which corresponds to more than 7500 micro-strain
Lufan Zou; Fabien Ravet; Xiaoyi Bao; Liang Chen
Usefulness of precise time stamping for exposing network characteristics on high-speed links
NASA Astrophysics Data System (ADS)
To expose network characteristics by active/passive measurements, measuring some timing issues such as one-way delay, one-way queuing delay, and inter-packet time is essential, and is conducted by time-stamping for packets passing through an observation point. However, emerging high-speed networks require very high precision of time-stamping, far beyond the precision of conventional software-based time-stamping systems such as 'tcpdump'. For example, the inter-packet time of two consecutive 64-byte length packets on a giga-bit link can be less than 0.001 msec. In this paper, to demonstrate the usefulness and strong necessity of precise time-stamping on high-speed links, experiments of network measurements over a nation-wide IPv6 testbed in Japan have been performed, using a hardware-based time-stamping system that can synchronize to GPS with a high resolution of 0.0001 msec and within a small error of 0.0003 msec. In our experiments, several interesting results are seen, e.g., i) the distribution of one-way queuing delay exhibits a considerable difference depending on the size and the type (UDP/ICMP) of packets; ii) the minimal one-way delays for various sizes of UDP/ICMP packets give an accurate estimate of the transmission delay and the propagation delay; iii) the correlation between interpacket times at the sender and the receiver sides in a sequence of TCP ACK packets clearly shows the degree of ACK compression; iv) the inter-packet time in a UDP stream generated by a DV streaming application shows three dominant sending rates and a very rare peak rate, which might provide crucial information to bandwidth dimensioning; all of which would indicate the usefulness of precise time-stamping.
Kitatsuji, Yoshinori; Tsuru, Masato; Katsuno, Satoshi; Oie, Yuji
The digital and high-precision error detection of complex freeform surface
The exploitation and modification of automobile die attach great importance to the automobile exploitation. It should be realized in the process of modifying mould-obtaining 3D model by reverse engineering-testing errors-confirming model. This thesis applies the method of ATOS Optical Scanner and CMM (Three-Coordinate Measuring Machine) to obtain the complete high-precision point cloud data because of the complicated free form surface
Hongsheng Fu; Luyue Ju; Xuexia Li
High-precision gravity network to monitor temporal variations in gravity across Yucca Mountain, Nevada
Repeatable high-precision gravity surveys provide a method of monitoring temporal variations in the gravity field. Fluctuations in the gravity field may indicate water table changes, crustal deformation, or precursors to volcanism and earthquakes. This report describes a high-precision gravity loop which has been established across Yucca Mountain, Nevada in support of the Nevada Nuclear Waste Storage Investigations (NNWSI) program. The purpose of this gravity loop is to monitor temporal variations in gravity across Yucca Mountain in an effort to interpret and predict the stability of the tectonic framework and changes in the subsurface density field. Studies of the tectonic framework which include volcanic hazard seismicity, and faulting studies are in progress. Repeat high-precision gravity surveys are less expensive and can be made more rapidly than a corresponding leveling survey. High-precision gravity surveys are capable of detecting elevation changes of 3 to 5 cm, and thus can be employed as an efficient tool for monitoring vertical crustal movements while supplementing or partially replacing leveling data. The Yucca Mountain gravity network has been tied to absolute gravity measurements established in southern Nevada. These ties provide an absolute datum for comparing repeat occupations of the gravity network, and provide a method of monitoring broad-scale changes in gravity. Absolute gravity measurements were also made at the bottom and top of the Charleston Peak calibration loop in southern Nevada. These absolute gravity measurements provide local control of calibrating gravity meters over the gravity ranges observed at Yucca Mountain. 13 refs., 7 figs., 3 tabs.
Harris, R.N.; Ponce, D.A.
MEMS - Frequency Agile High Precision Ranging under the Dual Use Applications Program (DUAP)
The objective of this program was laboratory demonstration of a low cost, jamming resistant, precision ranging system (radar) for proximity fuze and short-range measurement systems. Two approaches were envisioned: (1) The baseline-a baseband system directly radiating and detecting a random sequence of short pulses and (2) A higher risk design based on a transmitter using high-speed modulation of a micro-electromechanical
Paul Bauhahn
Design Considerations for a Modular High Precision 3D Coordinate Measuring Machine
The appearance of micro electromechanical elements increased demand can be observed for 3D coordinate measuring having submicron measuring uncertainty. The paper gives an overview of various designs and describes the construction of a small (100times100times100 mm) high precision (0.01 mum resolution, less then 0.1 mum measuring uncertainty over the full range) coordinate measuring machine. It has a novel motion system
Gyula Hermann
Algorithmic Design of High-Precision Low-Power MultiStage Decimation Filters
An algorithm for design of high-precision low- power decimation filters for DeltaSigma analog-to-digital converters is described. This algorithm has been applied to decimation filters with oversampling ratios of 32 to 256, passband ripples of 2 to 0.0003 dB, stopband attenuation of -30 to -120 dB, and passband edge of 0.35 fs to 0.454 fs, where fs is the output sampling
S. M. Mortazavi Zanjani; S. Rahimian Omam; S. M. Fakhraie; O. Shoaei
Development of a high-precision slit for x-ray beamline at SPring8
A high-precision slit for monochromatic x-rays has been developed as one of the standardized components in the undulator beamline at SPring-8. Advanced experiments such as x-ray micro-beam diffraction and x-ray scanning microscope using nano-beam require small, variable and accurate apertures. The newly developed slit has an aperture size ranging from 1 mum ū 1 mum to 20 mm ū 20
T. Takeuchi; M. Tanaka; T. Miura; Y. Senba; Y. Shimada; H. Tajiri; O. Sakata; M. Sato; T. Koganezawa; K. Uesugi; H. Ohashi; S. Goto
An Improved High-Precision Device for Astrometric Observations in Lunar Conditions
NASA Astrophysics Data System (ADS)
On the basis of a common analysis of specific features of the lunar environment as well as of the restrictions on the conditions of carrying out space experiments, the design has been improved for the completely automatic device VPA-2 for high-precision astrometric observations directly from the lunar surface, using the equal-altitude method with the photoelectric registration of transit moments of a series of stars. The parameters of the device VPA-2 are presented.
Gurshtein, A. A.
Follow-up Observations of Transiting Exoplanets with High-Precision Narrow-band Photometry
Ground and space-based exoplanet searches have already discovered several Neptune-size planets and are rapidly closing in on ``Super-Earths'' and ultimately Earth-like planets. For planets that transit their host stars, follow-up photometric observations enable the characterization of the planet's physical and orbital properties. Traditionally, ground-based photometry is performed using broad-band filters to maximize throughput and minimize photon noise. For high-precision ground-based
Eric B. Ford; K. D. Colon; C. Blake; B. L. Lee; S. Mahadevan
Ultrashort pulse Cr4+:YAG laser for high precision infrared frequency interval measurements
A cavity stabilized, SESAM mode-locked Cr4+:YAG laser capable of generating sub-100 fs pulses has been developed. Locking the 130-MHz pulse repetition frequency to that of a hydrogen maser-referenced frequency synthesizer provides a 30-nm wide frequency comb for the 1530-nm wavelength region. In conjunction with a pair of acetylene stabilized, external cavity diode lasers, this laser provides a high precision measurement tool for the determination of acetylene transition frequencies.
Alcock, A. J.; Ma, P.; Poole, P. J.; Chepurov, S.; Czajkowski, A.; Bernard, J. E.; Madej, A. A.; Fraser, J. M.; Mitchell, I. V.; Sorokina, I. T.; Sorokin, E.
Signal processing for high-precision wavefront control in adaptive optics
I presents new methods for high-precision wavefront control in Adaptive Optics (AO). All are built on a foundation of signal processing, in particular the use of the Fourier transform. The spatially-filtered wavefront sensor removes aliasing in the sampled measurements of the wavefront phase. Use of the spatial filter results in a dark hole in the point-spread-function (PSF). Inside this dark
Lisa Ann Poyneer
Seismic vibrations in bulk blasting with high-precise electronic and nonelectric blasting systems at quarries
The authors report measurement data on seismic waves in bulk blasting at quarries by using new high-precise electronic and\\u000a pyrotechnic blasting systems. It is proved that both systems are efficient, intensity of seismic waves is much lower in large-scale\\u000a bulk blasting. The authors implemented numerical modeling of seismic wave propagation under a short-delay bulk blast at a\\u000a quarry. Influence of
E. N. Sher; A. G. Chernikov
High precision micro-displacement fiber sensor through a suspended-core Sagnac interferometer.
A sensing system for micro-displacement measurement based in a suspended-core fiber Sagnac interferometer is presented. The suspended-core fiber characterization was made through the use of an optical backscatter reflectometer, screening its multimodal and birefringent behavior. Its sensitivity to displacement measurements is shown to be due only to birefringence, being that core-cladding mode coupling is negligible. High precision (~0.45 ?m) was obtained using three different measurement instruments, showing an extremely high stability and high insensitivity to temperature, demonstrating that the sensing system has the ability for low cost applications. PMID:22854467
Bravo, M; Pinto, A M R; Lopez-Amo, M; Kobelke, J; Schuster, K
High Precision Topographic Mapping at Chang'E-3 Landing Site with Multi-Source Data
NASA Astrophysics Data System (ADS)
Chang'e-3 (CE-3) is the first lander and rover of China following the success of Chang'e-1 and Chang'e-2 (CE-2) orbiters. High precision topographic mapping can provide detailed terrain information to ensure the safety of the rover as well as to support scientific investigations. In this research, multi-source data are co-registered into a uniform geographic framework for high precision topographic mapping at the CE-3 landing site. CE-2 CCD images with 7 m- and 1.5 m- resolutions are registered using selfcalibration bundle adjustment method with ground control points (GCPs) selected from LRO WAC mosaic map and LOLA DTM. The trajectory of CE-3 descent images are recovered using self-calibration free net bundle adjustment, and then the topographic data is rectified by absolute orientation with GCPs selected from the adjusted CE-2 DEM and DOM. Finally, these topographic data are integrated into the same geographic framework for unified, multi-scale, high precision mapping of the CE-3 landing site. Key technologies and the mapping products of this research have been used to support the surface operations of CE-3 mission.
Liu, Y.; Liu, B.; Xu, B.; Liu, Z.; Di, K.; Zhou, J.
Recent Operational Improvements To High Precision Photometric Observations With Warm IRAC
NASA Astrophysics Data System (ADS)
We present recent improvements to the data taking for high precision photometric observations with warm IRAC. The IRAC 3.6 and 4.5 ?m observations have significant photometric systematics due to a coupling of telescope motions with intra-pixel gain variations. These systematics are being trended with increasingly sophisticated techniques by the community (e.g. Ballard et al. 2010). A significant systematic due to a pointing wobble was reduced by 50% permitting observers to achieve precisions of 60 ppm (Demory et al. 2011). Most recently, use of the optical peakup instrument aboard Spitzer has been tested to place all IRAC staring mode observations on the same portion of a pixel. These tests have been effective in placing repeated epochs in the same 0.24 by 0.24 arcsec region of a pixel which has a minimal gain variation (sweet-spot). Preliminary high precision ( 10-4) gain maps of the sweet-spots will be presented. Coupled with science data taken at these sweet-spots, the gain maps will improve the ability to remove systematics from photometry. Results from demonstration observations of KOI-069 will be presented. The peakup mode has been tested for targets with V magnitude between 7 and 12.5. In limited testing, peakups using guide stars have been shown effective for stars outside this magnitude range. Full commissioning of the mode is ongoing with the expectation that all high-precision photometric observations will use peakups by the beginning of 2012. Use of the mode can continue as long as Spitzer is operating and should permit photon-limited follow-up and characteriztion of all Kepler discoveries. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech.
Carey, Sean J.; Krick, J.; Ingalls, J.; von Braun, K.; Stauffer, J.; Charbonneau, D.; Ballard, S.; Fisher, M.; Olds, R.
Algorithm research of high-precision optical interferometric phase demodulation based on FPGA
NASA Astrophysics Data System (ADS)
Optical interferometric phase demodulation algorithm is provided based on the principle of phase generated carrier (PGC), which can realize the optical interference measurement of high-precision signal demodulation, applied to optical fiber displacement, vibration sensor. Modulated photoelectric detection signal is performanced by interval 8 frequency multiplication sampling. The samples calculate the phase modulation depth and phase error through a feedback loop to achieve optimum working point control. On the other hand the results of sampling calculate precision of numerical of the phase. The algorithm uses the addition and subtraction method instead of correlation filtering and other related complex calculation process of the traditional PGC digital demodulation, making full use of FPGA data processing with advantage of high speed and parallel; This method can give full play to the advantage of FPGA performance. Otherwise, the speed at the same time, FPGA can also ensure that the phase demodulation precision, wide dynamic range, and give full play to the advantage of completing the data access by single clock cycle.
Zhi, Chunxiao; Sun, Jinghua
High Precision Oxygen Three Isotope Analysis of Wild-2 Particles and Anhydrous Chondritic Interplanetary Dust Particles
NASA Technical Reports Server (NTRS)
One of the most important discoveries from comet Wild-2 samples was observation of crystalline silicate particles that resemble chondrules and CAIs in carbonaceous chondrites. Previous oxygen isotope analyses of crystalline silicate terminal particles showed heterogeneous oxygen isotope ratios with delta(sup 18)O to approx. delta(sup 17)O down to -50% in the CAI-like particle Inti, a relict olivine grain in Gozen-sama, and an olivine particle. However, many Wild-2 particles as well as ferromagnesian silicates in anhydrous interplanetary dust particles (IDPs) showed Delta(sup 17)O values that cluster around -2%. In carbonaceous chondrites, chondrules seem to show two major isotope reservoirs with Delta(sup 17)O values at -5% and -2%. It was suggested that the Delta(sup 17)O = -2% is the common oxygen isotope reservoir for carbonaceous chondrite chondrules and cometary dust, from the outer asteroid belt to the Kuiper belt region. However, a larger dataset with high precision isotope analyses (+/-1-2%) is still needed to resolve the similarities or distinctions among Wild-2 particles, IDPs and chondrules in meteorites. We have made signifi-cant efforts to establish routine analyses of small particles (< or =10micronsm) at 1-2% precision using IMS-1280 at WiscSIMS laboratory. Here we report new results of high precision oxygen isotope analyses of Wild-2 particles and anhydrous chondritic IDPs, and discuss the relationship between the cometary dust and carbonaceous chondrite chondrules.
Nakashima, D.; Ushikubo, T.; Zolensky, Michael E.; Weisberg, M. K.; Joswiak, D. J.; Brownlee, D. E.; Matrajt, G.; Kita, N. T.
[High-precision measurement of spherical mirror reflectivity in vacuum ultraviolet spectrum].
In order to directly measure the vacuum ultraviolet spectrum reflectance of spherical mirror a measurement system was established. The system consists of monochromatic light source with deuterium lamp of magnesium fluoride window and Seya-Namioka concave grating monochromator, optical compensator with reflection modulator and reference detector and the receiving system with 80 mm diameter fluorescence integrating sphere and precision turntable. The optical compensation eliminates the instability in monochromatic light source, and the fluorescence integrating sphere eliminates the impact of light spot sizes in the two measurements, and reduce the system energy loss. The system measures the spherical mirror reflectivity in 115-180 nm, and the measurement result show that the repeatability is less than +/- 0.3%, and the relative uncertainty is less than 1.3%. The spherical mirror reflectivity achieves high-precision measurement. PMID:21428105
Li, Bo; Wang, Shu-Rong; Huang, Yu
High-Precision Branching Ratio Measurement for the Superallowed &+circ; emitter ^74Rb
NASA Astrophysics Data System (ADS)
Precision measurements of superallowed Fermi beta decay allow for tests of the Cabibbo-Kobayashi-Maskawa matrix (CKM) unitarity, the conserved vector current hypothesis, and the magnitude of isospin-symmetry-breaking effects in nuclei. A high-precision measurement of the branching ratio for the &+circ; decay of ^74Rb has been performed at the Isotope Separator and ACcelerator (ISAC) facility at TRIUMF. The 8? spectrometer, an array of 20 close-packed HPGe detectors, was used to detect gamma rays emitted following the decay of ^74Rb. PACES, an array of 5 Si(Li) detectors, was used to detect emitted conversion electrons, while SCEPTAR, an array of plastic scintillators, was used to detect emitted beta particles. In this talk, the importance of the branching ratio measurement of the ^74Rb superallowed decay will be discussed and preliminary results from the recent measurements at ISAC will be presented.
Dunlop, Ryan
High-precision ultra-distal Holocene tephrochronology in North America
NASA Astrophysics Data System (ADS)
Far-travelled volcanic ashes (tephras) from Holocene eruptions in Alaska and the Pacific northwest have been traced to the easternmost extent of North America, providing the basis for a new high-precision geochronological framework throughout the continent through tephrochronology (the dating and correlation of tephra isochrons in sedimentary records). The reported isochrons are geochemically distinct, with seven correlated to documented sources in Alaska and the Cascades, including the Mazama ash from Oregon (ś7600 years old) and the eastern lobe of the White River Ash from Alaska (ś1150 years old). These findings mark the beginning of a tephrochronological framework of enhanced precision across North America, with applications in palaeoclimate, surface process and archaeological studies. The particle travel distances involved (up to ś7000 km) also demonstrate the potential for continent-wide or trans-Atlantic socio-economic disruption from similar future eruptions.
Pyne-O'Donnell, Sean D. F.; Hughes, Paul D. M.; Froese, Duane G.; Jensen, Britta J. L.; Kuehn, Stephen C.; Mallon, Gunnar; Amesbury, Matthew J.; Charman, Dan J.; Daley, Tim J.; Loader, Neil J.; Mauquoy, Dmitri; Street-Perrott, F. Alayne; Woodman-Ralph, Jonathan
High precision topographic information from all available data is critical to many landing site geological and engineering applications. Meanwhile, precise navigation and localization of the rover is important for its safety, engineering and scientific objectives when it traverses the Martian surface. In order to support future long-range rover missions (for example, 1km traverse in the planned 2003 MER mission), high
Ron Li; Kaichang Di; Fengliang Xu; Larry H. Matthies; Clark F. Olson
Fabrication of high precision metallic freeform mirrors with magnetorheological finishing (MRF)
NASA Astrophysics Data System (ADS)
The fabrication of complex shaped metal mirrors for optical imaging is a classical application area of diamond machining techniques. Aspherical and freeform shaped optical components up to several 100 mm in diameter can be manufactured with high precision in an acceptable amount of time. However, applications are naturally limited to the infrared spectral region due to scatter losses for shorter wavelengths as a result of the remaining periodic diamond turning structure. Achieving diffraction limited performance in the visible spectrum demands for the application of additional polishing steps. Magnetorheological Finishing (MRF) is a powerful tool to improve figure and finish of complex shaped optics at the same time in a single processing step. The application of MRF as a figuring tool for precise metal mirrors is a nontrivial task since the technology was primarily developed for figuring and finishing a variety of other optical materials, such as glasses or glass ceramics. In the presented work, MRF is used as a figuring tool for diamond turned aluminum lightweight mirrors with electroless nickel plating. It is applied as a direct follow-up process after diamond machining of the mirrors. A high precision measurement setup, composed of an interferometer and an advanced Computer Generated Hologram with additional alignment features, allows for precise metrology of the freeform shaped optics in short measuring cycles. Shape deviations less than 150 nm PV / 20 nm rms are achieved reliably for freeform mirrors with apertures of more than 300 mm. Characterization of removable and induced spatial frequencies is carried out by investigating the Power Spectral Density.
Beier, Matthias; Scheiding, Sebastian; Gebhardt, Andreas; Loose, Roman; Risse, Stefan; Eberhardt, Ramona; T³nnermann, Andreas
A high-precision study of hindered diffusion near a wall
NASA Astrophysics Data System (ADS)
A high-precision study of hindered diffusion of a sphere due to its proximity to a solid interface was performed using an optical tweezer combined with digital holography microscopy and a phase-sensitive detection technique. The study provides a confirmation, with high accuracy and no adjustable parameters, of Faxen's law which describes the variation of the diffusivity of a sphere as a function of its distance from the wall in a Newtonian liquid due to hydrodynamic effects. This general technique is useful for application in microfluidics and lubrication of small devices with moving parts.
Sharma, Prerna; Ghosh, Shankar; Bhattacharya, S.
Lightweight Metal Matrix Composite Segmented for Manufacturing High-Precision Mirrors
NASA Technical Reports Server (NTRS)
High-precision mirrors for space applications are traditionally manufactured from one piece of material, such as lightweight glass sandwich or beryllium. The purpose of this project was to develop and test the feasibility of a manufacturing process capable of producing mirrors out of welded segments of AlBeMet(Registered Trademark) (AM162H). AlBeMet(Registered Trademark) is a HIP'd (hot isostatic pressed) material containing approximately 62% beryllium and 38% aluminum. As a result, AlBeMet shares many of the benefits of both of those materials for use in high performance mirrors, while minimizing many of their weaknesses.
Vudler, Vladimir
Development of a low cost high precision fabrication process for glass hybrid aspherical diffractive lenses
NASA Astrophysics Data System (ADS)
The hybrid aspherical diffractive singlet achromat design can be used to reduce chromatic aberration in compact optical systems. In this paper, the development of a compression molded, low cost and high precision hybrid diffractive glass lens is described. Specifically, an aspherical diffractive lens designed to compensate for chromatic aberration was fabricated by precision glass molding. The diffractive features are integrated on the aspherical surface to avoid mold alignment during fabrication. As part of the effort to lower manufacturing cost, the diffractive profiles were directly fabricated by single-point diamond turning without polishing. A thin layer of platinum-iridium coating was applied to the mold surfaces to protect the mold inserts from degradation during the molding process. In order to reduce thermal shrinkage error, the hybrid lens was fabricated using a two-step precision molding process on a commercial glass molding machine. The geometry of the molded hybrid aspherical diffractive lens was measured using an optical profilometer and the results demonstrated a match to the design mold profile with a replication error of 0.16% in the radial direction and 6.3% in the axial direction. In addition, an optical metrology system to evaluate the diffraction efficiency and chromatic focal shift was constructed and the measured results showed that the hybrid lenses indeed function as designed.
He, Peng; Wang, Fei; Li, Likai; Georgiadis, K.; Dambon, O.; Klocke, F.; Yi, A. Y.
High-precision simulations of the weak lensing effect on cosmic microwave background polarization
NASA Astrophysics Data System (ADS)
We studied the accuracy, robustness, and self-consistency of pixel-domain simulations of the gravitational lensing effect on the primordial cosmic microwave background (CMB) anisotropies due to the large-scale structure of the Universe. In particular, we investigated the dependence of the precision of the results precision on some crucial parameters of these techniques and propose a semi-analytic framework to determine their values so that the required precision is a priori assured and the numerical workload simultaneously optimized. Our focus was on the B-mode signal, but we also discuss other CMB observables, such as the total intensity, T, and E-mode polarization, emphasizing differences and similarities between all these cases. Our semi-analytic considerations are backed up by extensive numerical results. Those are obtained using a code, nicknamed lenS2HAT - for lensing using scalable spherical harmonic transforms (S2HAT) - which we have developed in the course of this work. The code implements a version of the previously described pixel-domain approach and permits performing the simulations at very high resolutions and data volumes, thanks to its efficient parallelization provided by the S2HAT library - a parallel library for calculating of the spherical harmonic transforms. The code is made publicly available.
Fabbian, Giulio; Stompor, Radek
A High Precision Method for Quantitative Measurements of Reactive Oxygen Species in Frozen Biopsies
Objective An electron paramagnetic resonance (EPR) technique using the spin probe cyclic hydroxylamine 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine (CMH) was introduced as a versatile method for high precision quantification of reactive oxygen species, including the superoxide radical in frozen biological samples such as cell suspensions, blood or biopsies. Materials and Methods Loss of measurement precision and accuracy due to variations in sample size and shape were minimized by assembling the sample in a well-defined volume. Measurement was carried out at low temperature (150 K) using a nitrogen flow Dewar. The signal intensity was measured from the EPR 1st derivative amplitude, and related to a sample, 3-carboxy-proxyl (CPĢ) with known spin concentration. Results The absolute spin concentration could be quantified with a precision and accuracy better than ▒10 ĄM (k?=?1). The spin concentration of samples stored at ?80░C could be reproduced after 6 months of storage well within the same error estimate. Conclusion The absolute spin concentration in wet biological samples such as biopsies, water solutions and cell cultures could be quantified with higher precision and accuracy than normally achievable using common techniques such as flat cells, tissue cells and various capillary tubes. In addition; biological samples could be collected and stored for future incubation with spin probe, and also further stored up to at least six months before EPR analysis, without loss of signal intensity. This opens for the possibility to store and transport incubated biological samples with known accuracy of the spin concentration over time.
Lindgren, Mikael; Gustafsson, Hakan
Maintaining high precision of isotope ratio analysis over extended periods of time.
Stable isotope ratios are reliable and long lasting process tracers. In order to compare data from different locations or different sampling times at a high level of precision, a measurement strategy must include reliable traceability to an international stable isotope scale via a reference material (RM). Since these international RMs are available in low quantities only, we have developed our own analysis schemes involving laboratory working RM. In addition, quality assurance RMs are used to control the long-term performance of the delta-value assignments. The analysis schemes allow the construction of quality assurance performance charts over years of operation. In this contribution, the performance of three typical techniques established in IsoLab at the MPI-BGC in Jena is discussed. The techniques are (1) isotope ratio mass spectrometry with an elemental analyser for delta(15)N and delta(13)C analysis of bulk (organic) material, (2) high precision delta(13)C and delta(18)O analysis of CO(2) in clean-air samples, and (3) stable isotope analysis of water samples using a high-temperature reaction with carbon. In addition, reference strategies on a laser ablation system for high spatial resolution delta(13)C analysis in tree rings is exemplified briefly. PMID:20183227
Brand, Willi A
High precision differential abundance measurements in globular clusters: chemical inhomogeneities in NGC 6752
NASA Astrophysics Data System (ADS)
We report on a strictly differential line-by-line analysis of high-quality UVES spectra of bright giants in the metal-poor globular cluster NGC 6752. We achieved high precision differential chemical abundance measurements for Fe, Na, Si, Ca, Ti, Cr, Ni, Zn, Y, Zr, Ba, La, Ce, Pr, Nd, Sm, Eu and Dy with uncertainties as low as ś0.01 dex (ś2 per cent). We obtained the following main results. (1) The observed abundance dispersions are a factor of ś2 larger than the average measurement uncertainty. (2) There are positive correlations, of high statistical significance, between all elements and Na. (3) For any pair of elements, there are positive correlations of high statistical significance, although the amplitudes of the abundance variations are small. Removing abundance trends with effective temperature and/or using a different pair of reference stars does not alter these results. These abundance variations and correlations may reflect a combination of (a) He abundance variations and (b) inhomogeneous chemical evolution in the pre- or protocluster environment. Regarding the former, the current constraints on ?Y from photometry likely preclude He as being the sole explanation. Regarding the latter, the nucleosynthetic source(s) must have synthesized Na, ?, Fe-peak and neutron-capture elements and in constant amounts for species heavier than Si; no individual object can achieve such nucleosynthesis. We speculate that other, if not all, globular clusters may exhibit comparable abundance variations and correlations to NGC 6752 if subjected to a similarly precise analysis.
Yong, David; Melķndez, Jorge; Grundahl, Frank; Roederer, Ian U.; Norris, John E.; Milone, A. P.; Marino, A. F.; Coelho, P.; McArthur, Barbara E.; Lind, K.; Collet, R.; Asplund, Martin
Plaskett Telescope high-precision line-scan camera encoder project
NASA Astrophysics Data System (ADS)
Improvements to the general dome conditions and the use of near IR detectors at the National Research Council of Canada's 1.8m Plaskett Telescope have stressed the abilities of the existing encoders. An encoding system that could be installed without telescope downtime and with a minimal impact on resources was necessary. These, and other, issues motivated the development of a method of non-contact encoding using a long line-scan CCD, a precision insensitive ruled tape and digital imaging metrology. Based on previously published simulation and experimental result a project to install such a system on the polar axis of the Plaskett Telescope was initiated. In this paper we present the overall design strategy, processing algorithms and initial test result and analysis. We end with recommendations to improve the capabilities of the approach.
Saddlemyer, Leslie K.; McLean, Gerard F.
ACT3: a high-speed, high-precision electrical impedance tomograph.
This paper presents the design, implementation, and performance of Rensselaer's third-generation Adaptive Current Tomograph, ACT3. This system uses 32 current sources and 32 phase-sensitive voltmeters to make a 32-electrode system that is capable of applying arbitrary spatial patterns of current. The instrumentation provides 16 b precision on both the current values and the real and reactive voltage readings and can collect the data for a single image in 133 ms. Additionally, the instrument is able to automatically calibrate its voltmeters and current sources and adjust the current source output impedance under computer control. The major system components are discussed in detail and performance results are given. Images obtained using stationary agar targets and a moving pendulum in a phantom as well as in vivo resistivity profiles showing human respiration are shown. PMID:7927393
Cook, R D; Saulnier, G J; Gisser, D G; Goble, J C; Newell, J C; Isaacson, D
Geotechnical pressure cell using a long-term reliable high-precision fiber optic sensor head
NASA Astrophysics Data System (ADS)
Geotechnical measurements are producing various data which are used for interpretation and e.g. safety calculation. The reliability of such data is of most importance as every decision on civil engineering action needed is based on this data. Known and also unknown influences changing data are a basic demand for deeper investigation and research. In present time we have limited tools only to minimize perturbing influences. One of these demands-the long-term development of data also called long-term stability-is described in this paper. The paper describes a sensor head for long-term high-precision measurements of very small deflections of a diaphragm used for pressure gauges. High precision deformation measurement is assured by using a fiber Fabry-Perot interferometer sensor; identification of zero-point changes, and thus, long-term stable measurement is achieved by a specially designed absolute interferometer sensor. Several fiber optic solutions based on fiber Fabry-Perot technique have been investigated to find out a reliable sensor design. The presented sensor design has reached prototype status and allows to measure unambiguously static deformations with high precision. In order to evaluate repeatability and possible changes of zero-point reference if the head has been disconnected, validation of the described pressure gauge has been started. This validation work includes calibration and enables to evaluate possible drift effects, and to identify mechanical or thermal hysteresis. Thus, the highlight in this paper is the observation and measurement of zero-point development over time.
Gloetzl, R.; Hofmann, D.; Basedau, F.; Habel, W.
A novel approach for high precision rapid potentiometric titrations: application to hydrazine assay.
We propose a high precision rapid personal computer (PC) based potentiometric titration technique using a specially designed mini-cell to carry out redox titrations for assay of chemicals in quality control laboratories attached to industrial, R&D, and nuclear establishments. Using this technique a few microlitre of sample (50-100 ?l) in a total volume of ~2 ml solution can be titrated and the waste generated after titration is extremely low comparing to that obtained from the conventional titration technique. The entire titration including online data acquisition followed by immediate offline analysis of data to get information about concentration of unknown sample is completed within a couple of minutes (about 2 min). This facility has been created using a new class of sensors, viz., pulsating sensors developed in-house. The basic concept in designing such instrument and the salient features of the titration device are presented in this paper. The performance of the titration facility was examined by conducting some of the high resolution redox titrations using dilute solutions--hydrazine against KIO(3) in HCl medium, Fe(II) against Ce(IV) and uranium using Davies-Gray method. The precision of titrations using this innovative approach lies between 0.048% and 1.0% relative standard deviation in different redox titrations. With the evolution of this rapid PC based titrator it was possible to develop a simple but high precision potentiometric titration technique for quick determination of hydrazine in nuclear fuel dissolver solution in the context of reprocessing of spent nuclear fuel in fast breeder reactors. PMID:22128994
Sahoo, P; Malathi, N; Ananthanarayanan, R; Praveen, K; Murali, N
High-Precision Distribution of Highly Stable Optical Pulse Trains with 8.8 x 10?19 instability
The high-precision distribution of optical pulse trains via fibre links has had a considerable impact in many fields. In most published work, the accuracy is still fundamentally limited by unavoidable noise sources, such as thermal and shot noise from conventional photodiodes and thermal noise from mixers. Here, we demonstrate a new high-precision timing distribution system that uses a highly precise phase detector to obviously reduce the effect of these limitations. Instead of using photodiodes and microwave mixers, we use several fibre Sagnac-loop-based optical-microwave phase detectors (OM-PDs) to achieve optical-electrical conversion and phase measurements, thereby suppressing the sources of noise and achieving ultra-high accuracy. The results of a distribution experiment using a 10-km fibre link indicate that our system exhibits a residual instability of 2.0 ū 10?15 at1?s and8.8 ū 10?19 at 40,000?s and an integrated timing jitter as low as 3.8?fs in a bandwidth of 1?Hz to 100?kHz. This low instability and timing jitter make it possible for our system to be used in the distribution of optical-clock signals or in applications that require extremely accurate frequency/time synchronisation.
Ning, B.; Zhang, S. Y.; Hou, D.; Wu, J. T.; Li, Z. B.; Zhao, J. Y.
Graphic overlays in high-precision teleoperation: Current and future work at JPL
NASA Technical Reports Server (NTRS)
In space teleoperation additional problems arise, including signal transmission time delays. These can greatly reduce operator performance. Recent advances in graphics open new possibilities for addressing these and other problems. Currently a multi-camera system with normal 3-D TV and video graphics capabilities is being developed. Trained and untrained operators will be tested for high precision performance using two force reflecting hand controllers and a voice recognition system to control two robot arms and up to 5 movable stereo or non-stereo TV cameras. A number of new techniques of integrating TV and video graphics displays to improve operator training and performance in teleoperation and supervised automation are evaluated.
Diner, Daniel B.; Venema, Steven C.
On the recovery of gravity anomalies from high precision altimeter data
NASA Technical Reports Server (NTRS)
A model for the recovery of gravity anomalies from high precision altimeter data is derived which consists of small correction terms to the inverse Stokes' formula. The influence of unknown sea surface topography in the case of meandering currents such as the Gulf Stream is discussed. A formula was derived in order to estimate the accuracy of the gravity anomalies from the known accuracy of the altimeter data. It is shown that for the case of known harmonic coefficients of lower order the range of integration in Stokes inverse formula can be reduced very much.
Lelgemann, D.
High-precision optical-frequency dissemination on branching optical-fiber networks.
We present a technique for the simultaneous dissemination of high-precision optical-frequency signals to multiple independent remote sites on a branching optical-fiber network. The technique corrects optical-fiber length fluctuations at the output of the link, rather than at the input as is conventional. As the transmitted optical signal remains unaltered until it reaches the remote site, it can be transmitted simultaneously to multiple remote sites on an arbitrarily complex branching network. This technique maintains the same servo-loop bandwidth limit as in conventional techniques and is compatible with active telecommunication links. PMID:23903172
Schediwy, Sascha W; Gozzard, David; Baldwin, Kenneth G H; Orr, Brian J; Warrington, R Bruce; Aben, Guido; Luiten, Andre N
Tests of a Fast Plastic Scintillator for High-Precision Half-Life Measurements
NASA Astrophysics Data System (ADS)
A fast plastic scintillator detector is evaluated for possible use in an ongoing program of high-precision half-life measurements of short lived ? emitters. Using data taken at TRI-UMF's Isotope Separator and Accelerator Facility with a radioactive 26Na beam, a detailed investigation of potential systematic effects with this new detector setup is being performed. The technique will then be applied to other ?-decay half-life measurements including the superallowed Fermi ? emitters 10C, 14O, and T = 1/2 decay of 15O.
Laffoley, A. T.; Dunlop, R.; Finlay, P.; Leach, K. G.; Michetti-Wilson, J.; Rand, E. T.; Svensson, C. E.; Grinyer, G. F.; Thomas, J. C.; Ball, G.; Garnsworthy, A. B.; Hackman, G.; Orce, J. N.; Triambak, S.; Williams, S. J.; Andreoiu, C.; Cross, D.
High-precision branching-ratio measurement for the superallowed ?+ emitter 26Alm
NASA Astrophysics Data System (ADS)
A high-precision branching-ratio measurement for the superallowed ?+ emitter 26Alm was performed at the TRIUMF-ISAC radioactive ion beam facility. An upper limit of ?12 ppm at 90% confidence level was found for the second forbidden ?+ decay of 26Alm to the 21+ state at 1809 keV in 26Mg. An inclusive upper limit of ?15 ppm at 90% confidence level was found when considering all possible nonanalog ?+/EC decay branches of 26Alm, resulting in a superallowed branching ratio of 100.0000-0.0015+0%.
Finlay, P.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Andreoiu, C.; Austin, R. A. E.; Bandyopadhyay, D.; Cross, D. S.; Demand, G.; Djongolov, M.; Ettenauer, S.; Garrett, P. E.; Green, K. L.; Grinyer, G. F.; Hackman, G.; Leach, K. G.; Pearson, C. J.; Phillips, A. A.; Rand, E. T.; Sumithrarachchi, C. S.; Triambak, S.; Williams, S. J.
The Asymmetric, Dual-Michelson Wavefront Corrector: High Precision Correction of Amplitude and Phase for Coronagraphy
NASA Technical Reports Server (NTRS)
To detect extra-solar planets by coronagraphy will require unprecedented levels of wavefront correction of both phase and amplitude. To achieve this, we propose a dual Michelson interferometer arrangement, incorporating two deformable mirrors (DM) and a third, fixed mirror (all at pupils) and two beamsplitters: one with unequal (asymmetric) beam splitting and one with symmetric beamsplitting. This design allows high precision correction of phase and amplitude using DMs with relatively coarse steps and is relatively insensitive to small changes in the DMs. We are constructing such an apparatus incorporating two MEMS devices and will report on features of the design performance.
Bowers, Charles; Woodgate, Bruce; Lyon, Richard
The Asymmetric, Dual-Michelson Wavefront Corrector: High Precision Correction of Amplitude and Phase for Coronagraphy
NASA Technical Reports Server (NTRS)
To detect extra-solar planets by coronography will require unprecedented levels of wavefront correction of both phase and amplitude. To achieve this, we propose a dual Michelson interferometer arrangement, incorporating two deformable mirrors (DM) and a third, fixed mirror (all at pupils) and two beamsplitters: one with unequal (asymmetric) beam splitting and one with symmetric beamsplitting. This design allows high precision correction of phase and amplitude using DMs with relatively coarse steps and is relatively insensitive to small changes in the DMs. We are constructing such an apparatus incorporating two MEMS devices and will report on features of the design and performance.
Bowers, Charles; Woodgate, Bruce; Lyon, Richard
[High-precision 3D morphology measurement by digital gatling method based on structured light].
In order to measure the microscopic 3D morphology of the objects with high-precision, a 3D texture measurement system of digital gatling based on structured light was designed, which can calculate the 3D height information with the analytic phase method. First, the authors collected sixteen equal step phase images by the four-step equal step method, and calculated their main value by dividing them into four groups. Then, the authors found the average as the final phase main value. The pretreatment on the fringe was done by the adaptive Wiener filter and wavelet multi-threshold method to eliminate the various effects of noise, projector distortion and CCD camera distortion. Besides, gradient-oriented phase unwrapping algorithm based on multifrequency was introduced to avoid phase discontinuity point in the course phase unwrapping, and it was proven to be effective and stable. Experiments showed that the system's 3D resolution was 2.75 microm, and the high degree accuracy was better than 0.5 microm, when the system was running with the fringe parameter p0 = 22.7 mm(-1). In addition, the system has many advantages such as fast measuring, simple operation and non-contact, which can meet the need of the high precision measurement requirements for the microscopic 3D morphology. PMID:23240390
Luo, Gang-Yin; Tang, Yu-Guo; Qiao, Pei-Yu; Wang, Bi-Dou; Jia, Zan-Dong; Xu, Zhong
MCAO: Wavefront sensing only as a tool for high precision photometry?
NASA Astrophysics Data System (ADS)
In MCAO the correction of the wavefront for an extended Field of View is obtained at the expense of a stretching of the actual instantaneous meta-pupils over the high altitude layers, just to compensate their average curvature. While this effect does average out in long term exposures and is of secondary interest in compensated imaging, it gives the input for the idea of using MCAO-like information, collectable over a certain Field of View, to assess in a time resolved mode (not necessarily in real time) the actual geometrical light throughput in a given direction. In principle this would allow, with proper time tagging, to achieve high precision photometry, as part of the scintillation could be measured on line during the observation. Simple averaging of neighbor stars to flat field starlight, for example, represents the equivalent of this concept for the ground-layer correction only. It can be seen that, once a direction is defined, it is relevant only the derivative of the wavefront around or in the proximity of that edges, but the range at which this happen is a crucial parameter. However, the strong interest in high precision measurements of exoplanetary transits or asteroseismology could make this approach not as lunatic as it could sound. view
Viotto, V.; Ragazzoni, R.; Bergomi, M.; Brunelli, A.; Dima, M.; Farinato, J.; Magrin, D.; Marafatto, L.; Nascimbeni, V.; Piotto, G.
High Sensitive Precise 3D Accelerometer for Solar System Exploration with Unmanned Spacecrafts
NASA Astrophysics Data System (ADS)
Solutions of several space and geophysical tasks require creating high sensitive precise accelerometers with sensitivity in order of 10 -13 g. These several tasks are following: inertial navigation of the Earth and Space; gravimetry nearby the Earth and into Space; geology; geophysics; seismology etc. Accelerometers (gravimeters and gradientmeters) with required sensitivity are not available now. The best accelerometers in the world have sensitivity worth on 4-5 orders. It has been developed a new class of fiber-optical sensors (FOS) with light pulse modulation. These sensors have super high threshold sensitivity and wide (up to 10 orders) dynamic range, and can be used as a base for creating of measurement units of physical values as 3D superhigh sensitive precise accelerometers of linear accelerations that is suitable for highest requirements. The principle of operation of the FOS is organically combined with a digital signal processing. It allows decreasing hardware of the accelerometer due to using a usual air-borne or space-borne computer; correcting the influence of natural, design, technological drawbacks of FOS on measured results; neutralising the influence of extraordinary situations available during using of FOS; decreasing the influence of internal and external destabilising factors (as for FOS), such as oscillation of environment temperature, instability of pendulum cycle frequency of sensitive element of the accelerometer etc. We were conducted a quantitative estimation of precise opportunities of analogue FOS in structure of fiber optical measuring devices (FOMD) for elementary FOMD with analogue FOS built on modern element basis of fiber optics (FO), at following assumptions: absolute parameter stability of devices of FOS measuring path; single transmission band of registration path; maximum possible inserted in optical fiber (OF) a radiated power. Even at such idealized assumptions, a calculated value in limit reached minimum inaccuracy of measuring, by analogue FOS, has been ś 10-4 %. Substantially accessible values are yet worse on 2-3 order. The reason of poor precise performances of measurers on the basis of analogue FOS is metrologically poor quality of a stream of optical radiation carrying out role of the carrier and receptor of the information. It is a high level of photon noise and a small blanket intensity level. First reason reflects the fact of discreteness of flow of high-energy photons, and it is consequence of second one - smallness, on absolute value, of inserted power into OF from available radiation sources (RS). Works on improvement of FO elements are carrying out. Certainly, it will be created RS allow to insert enough of power into standard OF. But simple increasing of optical flow power in measuring path of FOS will not be able to decide radically the problem of increasing of measuring prices: with raising of power in proportion of square root of its value there is raising a power of photon noises - 1000-times increase of power promises only 30-times increase of measuring precise; insertion into OF more large power (ś 1 W for standard silicon OF) causes an appearance of non-linear effects in it, which destroying an operating principle of analogue FOS. Thus, it is needed to constatate impossibility of building, at that time, measurers of analogue FOS, concurated with traditional (electrical) measurers on measuring precise. At that all, advantages of FO, as basis of building of FO MD requires to find ways for decision of these problems. Analysis of problem of sensitivity of usual (analogue) FOS has brought us to conclusion about necessity of reviewing of principles of information signal forming in FOS and principles its next electronic processing. For radical increasing of accuracy of measurements with using FOS it is necessary to refuse analogue modulation of optical flow and to transfer to discreet its modulations, entering thus in optical flow new, non-optical, parameters, which will serve as recipients of the information. It allows to save up all advantages of FOS (carrier of in
Savenko, Y. V.; Demyanenko, P. O.; Zinkovskiy, Y. F.
MEMS - Frequency Agile High Precision Ranging under the Dual Use Applications Program (DUAP)
NASA Astrophysics Data System (ADS)
The objective of this program was laboratory demonstration of a low cost, jamming resistant, precision ranging system (radar) for proximity fuze and short-range measurement systems. Two approaches were envisioned: (1) The baseline-a baseband system directly radiating and detecting a random sequence of short pulses and (2) A higher risk design based on a transmitter using high-speed modulation of a micro-electromechanical (MEM) oscillator to avoid low frequency antenna radiation requirements. Size constraints drive the design toward small, single-chip monocycle pulse radar implemented in CMOS (Complementary Metal Oxide Semiconductors). This device with two external capacitors, a battery and a miniature antenna for the baseline approach is described in Figure 1-1. Triggering ranges from several inches to more than 6feet were demonstrated. Fabrication of MEM components on gallium arsenide for the second approach will require additional work. While CMOS technology is almost ideal for the long time-constant, multiple pulse integration circuits in the precision ranging receiver and most of the transmitter circuits, it is insufficient for submunition sensor final output amplifiers. The issue is the small size of the submunition antenna. Either step recovery diode circuit or higher performance output transistors are needed to generate the high frequency spectrum required for efficient radiation from these antennas. Using a 0.5-micron BiCMOS/Si(3e process, recently available for prototyping at MOSIS,' all of the required CMOS and faster output devices could be implemented with trivial modifications of the existing circuits.
Bauhahn, Paul
Diode Laser-based Sensor for High Precision Measurements of Ambient CO2
NASA Astrophysics Data System (ADS)
We report on the development of a new, high precision sensor for monitoring ambient CO2. This economical, robust, autonomous CO2 sensor is intended for widespread deployment in networks. We have developed a tunable diode laser-based absorption spectrometer, operating at a wavelength of 2 "▌m, which utilizes Integrated Cavity Output Spectroscopy (ICOS) to create an optical pathlength of 60 m in a physical pathlength of 20 cm. The sensor also uses Wavelength Modulation Spectroscopy for high sensitivity detection. We have achieved a precision of better than 1 part in 3000 for the dry air mixing ratio of CO2 for a 1 minute averaging period. The sensor design ensures a measurement cell having a small sample volume, which decreases the consumption of calibration gases. We also use an integrated dedicated microprocessor-based controller and signal processing electronics to achieve a small footprint. The sensor measures 20 x 43 x 56 cm and weighs 15 kg. The prototype was demonstrated at the University of New Hampshire's Atmospheric Observatory at Thompson Farm, in Durham, NH during June and July 2008. It was successfully intercompared with an NDIR sensor and operated automatically around the clock for 6 weeks. It was also intercompared with the NOAA NDIR sensor at the Boulder Atmospheric Observatory in Erie, CO in September 2008.
Sonnenfroh, D. M.; Parameswaran, K.; Varner, R.
High-precision work distributions for extreme nonequilibrium processes in large systems
NASA Astrophysics Data System (ADS)
The distributions of work for strongly nonequilibrium processes are studied using a very general form of a large-deviation approach, which allows one to study distributions down to extremely small probabilities of almost arbitrary quantities of interest for equilibrium, nonequilibrium stationary, and even nonstationary processes. The method is applied to quickly vary the external field in a wide range B =3?0 for a critical (T =2.269) two-dimensional Ising system of size L ūL=128ū128. To obtain free-energy differences from the work distributions, they must be studied in ranges where the probabilities are as small as 10-240, which is not possible using direct simulation approaches. By comparison with the exact free energies, which are available for this model for the zero-field case, one sees that the present approach allows one to obtain the free energy with a very high relative precision of 10-4. This works well also for a nonzero field, i.e., for a case where standard umbrella-sampling methods are not efficient to calculate free energies. Furthermore, for the present case it is verified that the resulting distributions of work for forward and backward processes fulfill Crooks theorem with high precision. Finally, the free energy for the Ising magnet as a function of the field strength is obtained.
Hartmann, Alexander K.
A high precision position sensor design and its signal processing algorithm for a maglev train.
High precision positioning technology for a kind of high speed maglev train with an electromagnetic suspension (EMS) system is studied. At first, the basic structure and functions of the position sensor are introduced and some key techniques to enhance the positioning precision are designed. Then, in order to further improve the positioning signal quality and the fault-tolerant ability of the sensor, a new kind of discrete-time tracking differentiator (TD) is proposed based on nonlinear optimal control theory. This new TD has good filtering and differentiating performances and a small calculation load. It is suitable for real-time signal processing. The stability, convergence property and frequency characteristics of the TD are studied and analyzed thoroughly. The delay constant of the TD is figured out and an effective time delay compensation algorithm is proposed. Based on the TD technology, a filtering process is introduced in to improve the positioning signal waveform when the sensor is under bad working conditions, and a two-sensor switching algorithm is designed to eliminate the positioning errors caused by the joint gaps of the long stator. The effectiveness and stability of the sensor and its signal processing algorithms are proved by the experiments on a test train during a long-term test run. PMID:22778582
Xue, Song; Long, Zhiqiang; He, Ning; Chang, Wensen
High-precision temporal constraints on intrusive magmatism of the Siberian Traps
NASA Astrophysics Data System (ADS)
The broad temporal coincidence between large igneous province magmatism and some of the most severe biotic/environmental crises in Earth history has led many to infer a causal connection between the two. Notable examples include the end-Permian mass extinction and eruption/emplacement of the Siberian Traps large igneous province (LIP) and the end-Triassic mass extinction and the Central Atlantic Magmatic Province. In models proposing a causal connection between LIP magmatism and the environmental changes that lead to mass extinction, gases and particulates injected into the atmosphere are thought to cause abrupt changes in climate and ocean chemistry sufficient to drive mass extinction of marine and terrestrial biota. Magmatism has been proposed to cause voluminous volatile release via contact metamorphism of the sedimentary rocks. In the case of the Siberian Traps LIP, the compositions of sedimentary rocks (carbonates, evaporates, organic-rich shales) that host sills and dikes are ideal for greenhouse gas generation. When coupled with the enormous volume of Siberian LIP intrusive rocks, there is the potential for volatile generation on a scale necessary to drive environmental changes and mass extinction. This model must be tested by comparing the timing of intrusive magmatism with that of the mass extinction. Coupled high-precision geochronology and astrochronology have constrained the timing of biotic crisis and associated environmental perturbations from the deca-millennial to sub-millennial timescale, suggesting that the biotic crisis was abrupt, occurring over < 100 ka. Published geochronology on sills and dikes from the LIP are sparse and lack the necessary precision to resolve the relative timing of the two events outside of age uncertainty. We present new high-precision U-Pb zircon geochronology on seventeen gabbroic sills from throughout the magmatic province. This includes samples from the mineralized and differentiated intrusions in the Noril'sk region, from the central portion of the magmatic province and from the massive sills in the southern region of the LIP, where many intrusions are associated with eruptive pipes proposed to be the main mechanism by which volatiles are injected into the upper atmosphere. Weighted mean 206Pb/238U dates have uncertainties that range from ▒ 44 to 180 ka. Such precision allows resolution of the relative timing of sill emplacement and the extinction interval outside of analytical uncertainty, allows the timescale of changes in the global carbon cycle to be compared to that of the LIP, and permits evaluation of the role of intrusive magmatism in the mass extinction and during the post-extinction biotic recovery interval.
Burgess, Seth; Bowring, Sam; Pavlov, Volodia E.; Veselovsky, Roman V.
[Experimental and theoretical high energy physics program
Experimental and theoretical high-energy physics research at Purdue is summarized in a number of reports. Subjects treated include the following: the CLEO experiment for the study of heavy flavor physics; gas microstrip detectors; particle astrophysics; affine Kac{endash}Moody algebra; nonperturbative mass bounds on scalar and fermion systems due to triviality and vacuum stability constraints; resonance neutrino oscillations; e{sup +}e{sup {minus}} collisions at CERN; {bar p}{endash}p collisions at FNAL; accelerator physics at Fermilab; development work for the SDC detector at SSC; TOPAZ; D-zero physics; physics beyond the standard model; and the Collider Detector at Fermilab. (RWR)
Finley, J.; Gaidos, J.A.; Loeffler, F.J.; McIlwain, R.L.; Miller, D.H.; Palfrey, T.R.; Shibata, E.I.; Shipsey, I.P.
Autoionizing high-Rydberg states of very heavy Be-like ions: A tool for precision spectroscopy
NASA Astrophysics Data System (ADS)
Autoionizing high-Rydberg states formed during the initial electron capture phase of dielectronic recombination (DR) provide a unique access to spectroscopic information of highly charged heavy ions. This paper summarizes recent experimental and theoretical studies on the low energy 1s 22p jnlj' ( j=1/2, 3/2) Be-like DR resonances associated with the 2s 1/2?2p j core excitations of the Li-like ions 19779Au 76+, 20892Pb 79+ and 23892U 89+. An extrapolation of the resonance energies of the 1s 22p 1/2nlj' ( n?20) Rydberg series to the series limits ( n??) yields the 2s 1/2-2p 1/2 transition energies. The experimental precision of below 100 meV for all three ions obtained with this photonfree spectroscopic method is comparable to the best optical measurements available and allows to test quantum electrodynamics of strong central fields on a level of below 7% of the ?2 contributions. Furthermore, our theoretical calculations show that the observed DR resonance positions sensitively depend on the charge distribution within the atomic nucleus.
Brandau, C.; Bartsch, T.; B÷hm, S.; B÷hme, C.; Hoffknecht, A.; Knopp, H.; Schippers, S.; Shi, W.; M³ller, A.; Gr³n, N.; Scheid, W.; Steih, T.; Bosch, F.; Franzke, B.; Kozhuharov, C.; Mokler, P. H.; Nolden, F.; Steck, M.; St÷hlker, T.; Stachura, Z.
A demonstration of high precision GPS orbit determination for geodetic applications
NASA Technical Reports Server (NTRS)
High precision orbit determination of Global Positioning System (GPS) satellites is a key requirement for GPS-based precise geodetic measurements and precise low-earth orbiter tracking, currently under study at JPL. Different strategies for orbit determination have been explored at JPL with data from a 1985 GPS field experiment. The most successful strategy uses multi-day arcs for orbit determination and includes fine tuning of spacecraft solar pressure coefficients and station zenith tropospheric delays using the GPS data. Average rms orbit repeatability values for 5 of the GPS satellites are 1.0, 1.2, and 1.7 m in altitude, cross-track, and down-track componenets when two independent 5-day fits are compared. Orbit predictions up to 24 hours outside the multi-day arcs agree within 4 m of independent solutions obtained with well tracked satellites in the prediction interval. Baseline repeatability improves with multi-day as compared to single-day arc orbit solutions. When tropospheric delay fluctuations are modeled with process noise, significant additional improvement in baseline repeatability is achieved. For a 246-km baseline, with 6-day arc solutions for GPS orbits, baseline repeatability is 2 parts in 100 million (0.4-0.6 cm) for east, north, and length components and 8 parts in 100 million for the vertical component. For 1314 and 1509 km baselines with the same orbits, baseline repeatability is 2 parts in 100 million for the north components (2-3 cm) and 4 parts in 100 million or better for east, length, and vertical components.
Lichten, S. M.; Border, J. S.
High-Precision Simulation of the Gravity Field of Rapidly-Rotating Barotropes in Hydrostatic Equilibrium
NASA Astrophysics Data System (ADS)
The so-called theory of figures (TOF) uses potential theory to solve for the structure of highly distorted rotating liquid planets in hydrostatic equilibrium. TOF is noteworthy both for its antiquity (Maclaurin 1742) and its mathematical complexity. Planned high-precision gravity measurements near the surfaces of Jupiter and Saturn (possibly detecting signals ~ microgal) will place unprecedented requirements on TOF, not because one expects hydrostatic equilibrium to that level, but because nonhydrostatic components in the surface gravity, at expected levels ~ 1 milligal, must be referenced to precise hydrostatic-equilibrium models. The Maclaurin spheroid is both a useful test of numerical TOF codes (Hubbard 2012, ApJ Lett 756:L15), and an approach to an efficient TOF code for arbitrary barotropes of variable density (Hubbard 2013, ApJ 768:43). For the latter, one trades off vertical resolution by replacing a continuous barotropic pressure-density relation with a stairstep relation, corresponding to N concentric Maclaurin spheroids (CMS), each of constant density. The benefit of this trade-off is that two-dimensional integrals over the mass distributions at each interface are reduced to one-dimensional integrals, quickly and accurately evaluated by Gaussian quadrature. The shapes of the spheroids comprise N level surfaces within the planet and at its surface, are gravitationally coupled to each other, and are found by self-consistent iteration, relaxing to a final configuration to within the computer's precision limits. The angular and radial variation of external gravity (using the usual geophysical expansion in multipole moments) can be found to the limit of typical floating point precision (~ 1.e-14), much better than the expected noise/signal for either the Juno or Cassini gravity experiments. The stairstep barotrope can be adjusted to fit a prescribed continuous or discontinuous interior barotrope, and can be made to approximate it to any required precision by increasing N. One can insert a higher density of CMSs toward the surface of an interior model in order to more accurately model high-order gravitational moments. The magnitude of high-order moments predicted by TOF declines geometrically with order number, and falls below the magnitude of expected non-hydrostatic terms produced by interior dynamics at ~ order 10 and above. Juno's sensitivity is enough to detect tidal gravity signals from Galilean satellites. The CMS method can be generalized to predict tidal zonal and tesseral terms consistent with an interior model fitted to measured zonal harmonics. For this purpose, two-dimensional Gaussian quadrature is necessary at each CMS interface. However, once the model is relaxed to equilibrium, one need not refit the model to the average zonal harmonics because of the smallness of the tidal terms. I will describe how the CMS method has been validated through comparisons with standard TOF models for which fully or partially analytic solutions exist, as well as through consistency checks. At this stage in software development in preparation for Jupiter orbit, we are focused on increasing the speed of the code in order to more efficiently search the parameter space of acceptable Jupiter interior models, as well as to interface it with advanced hydrogen-helium equations of state.
Hubbard, W. B.
High Precision Tune and Coupling Feedback and Beam Transfer Function Measurements in RHIC
Precision measurement and control of the betatron tunes and betatron coupling in the Relativistic Heavy Ion Collider (RHIC) are required for establishing and maintaining both good operating conditions and, particularly during the ramp to high beam energies, high proton beam polarization. While the proof-of-principle for simultaneous tune and coupling feedback was successfully demonstrated earlier, routine application of these systems has only become possible recently. Following numerous modifications for improved measurement resolution and feedback control, the time required to establish full-energy beams with the betatron tunes and coupling regulated by feedback was reduced from several weeks to a few hours. A summary of these improvements, select measurements benefitting from the improved resolution and a review of system performance are the subject of this report.
Minty, M.; Curcio, A.; Dawson, C.; Degen, C.; Luo, Y.; Marr, G.; Martin, B.; Marusic, A.; Mernick, K.; Oddo, P.; Russo, T.; Schoefer, V.; Schroeder, R.; Schultheiss, C.; Wilinski, M.
EFICAz2.5: application of a high-precision enzyme function predictor to 396 proteomes
Summary: High-quality enzyme function annotation is essential for understanding the biochemistry, metabolism and disease processes of organisms. Previously, we developed a multi-component high-precision enzyme function predictor, EFICAz2 (enzyme function inference by a combined approach). Here, we present an updated improved version, EFICAz2.5, that is trained on a significantly larger data set of enzyme sequences and PROSITE patterns. We also present the results of the application of EFICAz2.5 to the enzyme reannotation of 396 genomes cataloged in the ENSEMBL database. Availability: The EFICAz2.5 server and database is freely available with a use-friendly interface at http://cssb.biology.gatech.edu/EFICAz2.5. Contact: email@example.com Supplementary information: Supplementary data are available at Bioinformatics online.
Kumar, Narendra; Skolnick, Jeffrey
A Repository of Precision Flat Fields for High-Resolution MDI Continuum Data
NASA Astrophysics Data System (ADS)
We describe an archive of high-precision MDI flat fields that can be used to refine most MDI high-resolution continuum data. The archive consists of many flat-field images representing different time ranges over the full operating period of SOHO. The residual flat-field error on the standard level 1.5/1.8 calibrated continuum images represents a significant proportion (25% - 100%) of the true data variation data on the quiet sun. Using the flat fields in this archive will reduce that error by a factor of 10 - 30, greatly increasing the accuracy of any tracking or photometric operations. The access, use and accuracy of these flat fields are described in this paper.
Potts, H. E.; Diver, D. A.
A high-precision cryogenically-cooled crystal monochromator for the APS diagnostics beamline
A high-precision cryogenically-cooled crystal monochromator has been developed for the APS diagnostics beamline. The design permits simultaneous measurements of the particle beam size and divergence. It provides for a large rotation angle, {minus}15{degree} to 180{degree}, with a resolution of 0.0005{degree}. The roll angle of the crystal can be adjusted by up to {+-}3{degree} with a resolution of 0.0001{degree}. A vertical translational stage, with a stroke of {+-}25 mm and resolution of 8 {micro}m, is provided to enable using different parts of the same crystal or to retract the crystal from the beam path. The modular design will allow optimization of cooling schemes to minimize thermal distortions of the crystal under high heat loads.
Rotela, E.; Yang, B.; Sharma, s.; Barcikowski, A.
Implementation of the Mixed-Precision High Performance LINPACK Benchmark on the CELL Processor
This paper describes the design concepts behind im- plementations of mixed-precision linear algebra rou- tines targeted for the Cell processor. It describes in detail the implementation of code to solve linear sys- tem of equations using Gaussian elimination in single precision with iterative refinement of the solution to the full double precision accuracy. By utilizing this approach the algorithm achieves
Jakub Kurzak; Jack Dongarra
GPS inland water buoys for precise and high temporal resolution water level and movement monitoring
NASA Astrophysics Data System (ADS)
Monitoring of river and lake stages is one of the basic issues in understanding catchment hydrology and hydraulic systems. There are numerous techniques available for this, but in case of large water bodies technical as well as financial problems may restrict the use of traditional techniques. Therefore we explored the potential of GPS based altimetry for stage monitoring by developing small and easy to handle buoys with mounted high precision GPS devices. The advantages of the buoys are the freedom of positioning over the whole water body and their quick and easy deployment. The developed devices were tested in the Mekong Delta, Vietnam in two different locations: On the Mekong river where high currents over the flood season occur and in a small lake with hydraulic connections to a major channel with hardly any currents present. The collected GPS data were processed differentially and tested against standard pressure gauge data. The recorded stages proved to be of high quality and a valuable resource for flood monitoring and modeling. In addition to the stage data, the high-precision GPS positioning data could also be used for monitoring the movement of the buoys, from which alternating currents caused by ocean tides and flood waves could be detected, thus providing an additional information on the hydraulic system. We conclude that the developed buoys add well to the existing hydrological monitoring pool and are a goof option for the monitoring in large water bodies where a) traditional methods are technically difficult to deploy or are too costly, and b) where additional information about flow direction is needed.
Apel, Heiko; Nghia Hung, Nguyen; Thoss, Heiko; G³ntner, Andreas
The Generation of Higher-order Laguerre-Gauss Optical Beams for High-precision Interferometry
Thermal noise in high-reflectivity mirrors is a major impediment for several types of high-precision interferometric experiments that aim to reach the standard quantum limit or to cool mechanical systems to their quantum ground state. This is for example the case of future gravitational wave observatories, whose sensitivity to gravitational wave signals is expected to be limited in the most sensitive frequency band, by atomic vibration of their mirror masses. One promising approach being pursued to overcome this limitation is to employ higher-order Laguerre-Gauss (LG) optical beams in place of the conventionally used fundamental mode. Owing to their more homogeneous light intensity distribution these beams average more effectively over the thermally driven fluctuations of the mirror surface, which in turn reduces the uncertainty in the mirror position sensed by the laser light. We demonstrate a promising method to generate higher-order LG beams by shaping a fundamental Gaussian beam with the help of diffractive optical elements. We show that with conventional sensing and control techniques that are known for stabilizing fundamental laser beams, higher-order LG modes can be purified and stabilized just as well at a comparably high level. A set of diagnostic tools allows us to control and tailor the properties of generated LG beams. This enabled us to produce an LG beam with the highest purity reported to date. The demonstrated compatibility of higher-order LG modes with standard interferometry techniques and with the use of standard spherical optics makes them an ideal candidate for application in a future generation of high-precision interferometry.
Carbone, Ludovico; Fulda, Paul; Bond, Charlotte; Brueckner, Frank; Brown, Daniel; Wang, Mengyao; Lodhia, Deepali; Palmer, Rebecca; Freise, Andreas
High precision 11B/10B analysis with a simplified MC-ICP-MS
NASA Astrophysics Data System (ADS)
Boron isotope ratio is a powerful tracer in the fields of geochemistry, biochemistry, and environmental chemistry. One important application of 11B/10B isotope ratio in geochemistry is as an indicator for paleo pH of seawater recorded in marine carbonates in deep-sea sediments. Boron isotope ratios are determined by TIMS or MC-ICP-MS with precisions of better than 0.1 % RSD, but a large inter-lab discrepancy of 0.6 % is still observed for actual carbonate samples (Foster, 2008). Here, we tried to determine B isotope ratio by MC-ICP-MS with a simple and common analytical techniques using a quartz sample introduction system with a PFA nebulizer, and compared to recently developed precise B isotope ratio analysis techniques by TIMS in positive ion detection mode determined as Cs2BO2+ ions with sample amount of <100 ng (Ishikawa and Nagaishi, 2011) and by MC-ICP-MS (Foster, 2008, Louvat et al., 2011). 11B/10B isotope ratios of a 50 ppb B solution dissolved in a HNO3, mannitol, HF-mixed solution were determined against an isotopic reference NIST-SRM 951 with a standard sample bracketing technique in the wet plasma condition. Resultant analytical reproducibility (twice standard deviation) was +/-0.02 % with a consumption of 50 ng B, and the washout time was comparable to that of NH3 gas addition to the introduction system (Foster, 2008). 11B/10B isotope ratios of actual carbonate sample and seawater were determined after simple chemical purification with a common cation exchange resin instead of a boron selective resin. Their relative differences from the standard were consistent with those determined by the positive TIMS within analytical uncertainty. Current potential of MC-ICP-MS for precise B isotopic analysis will be discussed. Foster, G., 2008. Seawater pH, pCO2 and [CO32-] variations in the Caribbean Sea over the last 130kyr: A boron isotope and B/Ca study of planktic foraminifera, Earth Planet. Sci. Lett., 271, 254-266. Ishikawa, T. and Nagaishi, K., 2011. High-precision isotopic analysis of boron by positive thermal ionization mass spectrometry with sample preheating, J. Anal. At. Spectrom., 26, 359-365. Louvat, P., Bouchez, J, and Paris, G., 2011. MC-ICP-MS isotope measurements with direct injection nebulisation (d-DIHEN): Optimisation and application to boron in seawater and carbonate samples., Geostand. Geoanal. Res., 35, 75-88.
Tanimizu, M.; Nagaishi, K.
High-precision percolation thresholds and Potts-model critical manifolds from graph polynomials
NASA Astrophysics Data System (ADS)
The critical curves of the q-state Potts model can be determined exactly for regular two-dimensional lattices G that are of the three-terminal type. This comprises the square, triangular, hexagonal and bow¢tie lattices. Jacobsen and Scullard have defined a graph polynomial PB(q, v) that gives access to the critical manifold for general lattices. It depends on a finite repeating part of the lattice, called the basis B, and its real roots in the temperature variable v = eK ? 1 provide increasingly accurate approximations to the critical manifolds upon increasing the size of B. Using transfer matrix techniques, these authors computed PB(q, v) for large bases (up to 243 edges), obtaining determinations of the ferromagnetic critical point vc > 0 for the (4, 82), kagome, and (3, 122) lattices to a precision (of the order 10?8) slightly superior to that of the best available Monte Carlo simulations. In this paper we describe a more efficient transfer matrix approach to the computation of PB(q, v) that relies on a formulation within the periodic Temperley¢Lieb algebra. This makes possible computations for substantially larger bases (up to 882 edges), and the precision on vc is hence taken to the range 10?13. We further show that a large variety of regular lattices can be cast in a form suitable for this approach. This includes all Archimedean lattices, their duals and their medials. For all these lattices we tabulate high-precision estimates of the bond percolation thresholds pc and Potts critical points vc. We also trace and discuss the full Potts critical manifold in the (q, v) plane, paying special attention to the antiferromagnetic region v < 0. Finally, we adapt the technique to site percolation as well, and compute the polynomials PB(p) for certain Archimedean and dual lattices (those having only cubic and quartic vertices), using very large bases (up to 243 vertices). This produces the site percolation thresholds pc to a precision of the order of 10?9.
>Jesper Lykke Jacobsen, 2014-04-01
High-precision correlative fluorescence and electron cryo microscopy using two independent alignment markers.
Correlative light and electron microscopy (CLEM) is an emerging technique which combines functional information provided by fluorescence microscopy (FM) with the high-resolution structural information of electron microscopy (EM). So far, correlative cryo microscopy of frozen-hydrated samples has not reached better than micrometre range accuracy. Here, a method is presented that enables the correlation between fluorescently tagged proteins and electron cryo tomography (cryoET) data with nanometre range precision. Specifically, thin areas of vitrified whole cells are examined by correlative fluorescence cryo microscopy (cryoFM) and cryoET. Novel aspects of the presented cryoCLEM workflow not only include the implementation of two independent electron dense fluorescent markers to improve the precision of the alignment, but also the ability of obtaining an estimate of the correlation accuracy for each individual object of interest. The correlative workflow from plunge-freezing to cryoET is detailed step-by-step for the example of locating fluorescence-labelled adenovirus particles trafficking inside a cell. PMID:24262358
Schellenberger, Pascale; Kaufmann, Rainer; Siebert, C Alistair; Hagen, Christoph; Wodrich, Harald; Gr³newald, Kay
High-Precision Isothermal Titration Calorimetry with Automated Peak Shape Analysis
Isothermal titration calorimetry (ITC) is a powerful classical method that enables researchers in many fields to study the thermodynamics of molecular interactions. Primary ITC data comprise the temporal evolution of differential power reporting the heat of reaction during a series of injections of aliquots of a reactant into a sample cell. By integration of each injection peak, an isotherm can be constructed of total changes in enthalpy as a function of changes in solution composition, which is rich in thermodynamic information on the reaction. However, the signals from the injection peaks are superimposed by the stochastically varying time-course of the instrumental baseline power, limiting the precision of ITC isotherms. Here, we describe a method for automated peak assignment based on peak-shape analysis via singular value decomposition in combination with detailed least-squares modeling of local pre- and post-injection baselines. This approach can effectively filter out contributions of short-term noise and adventitious events in the power trace. This method also provides, for the first time, statistical error estimates for the individual isotherm data points. In turn, this results in improved detection limits for high-affinity or low-enthalpy binding reactions and significantly higher precision of the derived thermodynamic parameters.
Keller, Sandro; Vargas, Carolyn; Zhao, Huaying; Piszczek, Grzegorz; Brautigam, Chad A.; Schuck, Peter
High-precision isothermal titration calorimetry with automated peak-shape analysis.
Isothermal titration calorimetry (ITC) is a powerful classical method that enables researchers in many fields to study the thermodynamics of molecular interactions. Primary ITC data comprise the temporal evolution of differential power reporting the heat of reaction during a series of injections of aliquots of a reactant into a sample cell. By integration of each injection peak, an isotherm can be constructed of total changes in enthalpy as a function of changes in solution composition, which is rich in thermodynamic information on the reaction. However, the signals from the injection peaks are superimposed by the stochastically varying time-course of the instrumental baseline power, limiting the precision of ITC isotherms. Here, we describe a method for automated peak assignment based on peak-shape analysis via singular value decomposition in combination with detailed least-squares modeling of local pre- and postinjection baselines. This approach can effectively filter out contributions of short-term noise and adventitious events in the power trace. This method also provides, for the first time, statistical error estimates for the individual isotherm data points. In turn, this results in improved detection limits for high-affinity or low-enthalpy binding reactions and significantly higher precision of the derived thermodynamic parameters. PMID:22530732
Keller, Sandro; Vargas, Carolyn; Zhao, Huaying; Piszczek, Grzegorz; Brautigam, Chad A; Schuck, Peter
Quantifying Condition-Dependent Intracellular Protein Levels Enables High-Precision Fitness Estimates
Countless studies monitor the growth rate of microbial populations as a measure of fitness. However, an enormous gap separates growth-rate differences measurable in the laboratory from those that natural selection can distinguish efficiently. Taking advantage of the recent discovery that transcript and protein levels in budding yeast closely track growth rate, we explore the possibility that growth rate can be more sensitively inferred by monitoring the proteomic response to growth, rather than growth itself. We find a set of proteins whose levels, in aggregate, enable prediction of growth rate to a higher precision than direct measurements. However, we find little overlap between these proteins and those that closely track growth rate in other studies. These results suggest that, in yeast, the pathways that set the pace of cell division can differ depending on the growth-altering stimulus. Still, with proper validation, protein measurements can provide high-precision growth estimates that allow extension of phenotypic growth-based assays closer to the limits of evolutionary selection.
Geiler-Samerotte, Kerry A.; Hashimoto, Tatsunori; Dion, Michael F.; Budnik, Bogdan A.; Airoldi, Edoardo M.; Drummond, D. Allan
High-precision correlative fluorescence and electron cryo microscopy using two independent alignment markers?
Correlative light and electron microscopy (CLEM) is an emerging technique which combines functional information provided by fluorescence microscopy (FM) with the high-resolution structural information of electron microscopy (EM). So far, correlative cryo microscopy of frozen-hydrated samples has not reached better than micrometre range accuracy. Here, a method is presented that enables the correlation between fluorescently tagged proteins and electron cryo tomography (cryoET) data with nanometre range precision. Specifically, thin areas of vitrified whole cells are examined by correlative fluorescence cryo microscopy (cryoFM) and cryoET. Novel aspects of the presented cryoCLEM workflow not only include the implementation of two independent electron dense fluorescent markers to improve the precision of the alignment, but also the ability of obtaining an estimate of the correlation accuracy for each individual object of interest. The correlative workflow from plunge-freezing to cryoET is detailed step-by-step for the example of locating fluorescence-labelled adenovirus particles trafficking inside a cell.
Schellenberger, Pascale; Kaufmann, Rainer; Siebert, C. Alistair; Hagen, Christoph; Wodrich, Harald; Grunewald, Kay
A high precision comprehensive evaluation method for flood disaster loss based on improved genetic programming
NASA Astrophysics Data System (ADS)
Precise comprehensive evaluation of flood disaster loss is significant for the prevention and mitigation of flood disasters. Here, one of the difficulties involved is how to establish a model capable of describing the complex relation between the input and output data of the system of flood disaster loss. Genetic programming (GP) solves problems by using ideas from genetic algorithm and generates computer programs automatically. In this study a new method named the evaluation of the grade of flood disaster loss (EGFD) on the basis of improved genetic programming (IGP) is presented (IGP-EGFD). The flood disaster area and the direct economic loss are taken as the evaluation indexes of flood disaster loss. Obviously that the larger the evaluation index value, the larger the corresponding value of the grade of flood disaster loss is. Consequently the IGP code is designed to make the value of the grade of flood disaster be an increasing function of the index value. The result of the application of the IGP-EGFD model to Henan Province shows that a good function expression can be obtained within a bigger searched function space; and the model is of high precision and considerable practical significance. Thus, IGP-EGFD can be widely used in automatic modeling and other evaluation systems.
Zhou, Yuliang; Lu, Guihua; Jin, Juliang; Tong, Fang; Zhou, Ping
Precise color images a high-speed color video camera system with three intensified sensors
NASA Astrophysics Data System (ADS)
High speed imaging systems have been used in a large field of science and engineering. Although the high speed camera systems have been improved to high performance, most of their applications are only to get high speed motion pictures. However, in some fields of science and technology, it is useful to get some other information, such as temperature of combustion flame, thermal plasma and molten materials. Recent digital high speed video imaging technology should be able to get such information from those objects. For this purpose, we have already developed a high speed video camera system with three-intensified-sensors and cubic prism image splitter. The maximum frame rate is 40,500 pps (picture per second) at 64 X 64 pixels and 4,500 pps at 256 X 256 pixels with 256 (8 bit) intensity resolution for each pixel. The camera system can store more than 1,000 pictures continuously in solid state memory. In order to get the precise color images from this camera system, we need to develop a digital technique, which consists of a computer program and ancillary instruments, to adjust displacement of images taken from two or three image sensors and to calibrate relationship between incident light intensity and corresponding digital output signals. In this paper, the digital technique for pixel-based displacement adjustment are proposed. Although the displacement of the corresponding circle was more than 8 pixels in original image, the displacement was adjusted within 0.2 pixels at most by this method.
Oki, Sachio; Yamakawa, Masafumi; Gohda, Susumu; Etoh, Takeharu
High-resolution estimation of the water balance of high-precision lysimeters
NASA Astrophysics Data System (ADS)
Lysimeters offer the opportunity to determine precipitation, evapotranspiration and groundwater recharge with high accuracy. In comparison to other techniques, like Eddy-flux-systems or evaporation pans, lysimeters provide a direct measurement of evapotranspiration via the built-in weighing system. The measurement of precipitation can benefit of the much higher surface area compared to typical rain gauge systems. Nevertheless, lysimeters are exposed to several external influences that could falsify the calculated fluxes. Therefore, the estimation of the relevant fluxes requires an adequate data processing, while accounting for the various possible error sources. Most lysimeter studies correct noise in the data by applying a smoothing of the data using a time window of about one hour. These high averaging times can lead to a falsification of the water balance and a loss of information on the dynamics of the processes. In the present study, we present a processing scheme which is based on five filter components that refer to different possible error sources and allow a simple implementation. We further use a set of 12 crop lysimeters and 6 grass lysimeters of the TERENO SoilCan research site Bad Lauchstõdt to show that a temporally highly resolved data processing of lysimeter data with a high temporal resolution and good accuracy is possible.
Hannes, Matthias; Wollschlõger, Ute; Vogel, Hans-J÷rg; Fank, Johann; P³tz, Thomas; Durner, Wolfgang; Schrader, Frederik; Gebler, Sebastian
Interferometry based high-precision dilatometry for dimensional characterization of highly stable materials
NASA Astrophysics Data System (ADS)
We present an optical dilatometer for high-accuracy and high-resolution absolute measurement of the linear coefficient of thermal expansion (CTEl). Based on a highly symmetric differential heterodyne interferometer, dimensional changes of a tubular shaped specimen under controlled thermal conditions can be characterized. Our measurement facility is located in vacuum where the test specimen can be temperature controlled in a temperature range between 20 ░C and 60 ░C. A thermally stable support and two identical isostatic mirror clamps were specifically designed to fix a reference and a measurement mirror inside the tube enabling a measurement, where no load in the axial direction was applied to the device under test (DUT). We measured the linear CTE of two carbon-fibre reinforced plastic (CFRP) tubes with different predicted linear CTEs at room temperature: -0.647 ū 10-6 K-1 and 0 ▒ 2.5 ū 10-9 K-1, respectively. Currently, we are investigating the manufacture limitations of the CFRP and the limitations of our apparatus in terms of measurement accuracy. In the next step, we will characterize a specifically manufactured zero-class ZerodurÖ tube with a CTEl value <10 ū 10-9 K-1. Due to its high thermal stability and non-directional structural isotropy this material has been chosen for macroscopic calibration of the metrology system. The results of these measurements will thus provide the resolution limitations of our facility and can be taken as an absolute accuracy reference.
Cordero, J.; Heinrich, T.; Schuldt, T.; Gohlke, M.; Lucarelli, S.; Weise, D.; Johann, U.; Braxmaier, C.
Classical Cepheids: High-precision Velocimetry, Cluster Membership, and the Effect of Rotation
NASA Astrophysics Data System (ADS)
Classical Cepheids are crucial calibrators of the extragalactic distance scale. Despite the adjective 'classical' and their use as 'standard candles', many open problems remain and ensure a steady scientific interest in these objects. This thesis has contributed to the understanding of Cepheids via three different topics: (1) an unprecedented observational program dedicated to studying highly precise Doppler measurements (velocimetry), which as has enabled several observational discoveries; (2) a newly-developed astro-statistical method for conducting an all-sky census of Cepheids belonging to Galactic open clusters, which is suitable for the era of large surveys (big data) such as the ESA's Gaia space mission; (3) the first detailed investigation of the effect of rotation on populations of classical Cepheids using Geneva stellar evolution models, which provides an explanation for the 45-year old Cepheid mass discrepancy problem. Last, but not least, I investigated the implications of my work for the extragalactic distance scale.
Anderson, Richard I.
Development of a high-precision slit for x-ray beamline at SPring-8
NASA Astrophysics Data System (ADS)
A high-precision slit for monochromatic x-rays has been developed as one of the standardized components in the undulator beamline at SPring-8. Advanced experiments such as x-ray micro-beam diffraction and x-ray scanning microscope using nano-beam require small, variable and accurate apertures. The newly developed slit has an aperture size ranging from 1 ?m ū 1 ?m to 20 mm ū 20 mm with a resolution of 0.5 ?m in full step. Each blade is independently driven through bellows mounted on both sides of the vacuum chamber. A set of bellows prevents displacement of the blade by evacuation. Using this slit, we could improve the displacement from 20 ?m to 1 ?m. The positioning accuracy of the slit is 0.5 ?m. The slits have been installed in the three beamlines at SPring-8.
Takeuchi, T.; Tanaka, M.; Miura, T.; Senba, Y.; Shimada, Y.; Tajiri, H.; Sakata, O.; Sato, M.; Koganezawa, T.; Uesugi, K.; Ohashi, H.; Goto, S.
High Precision Measurement of the Proton Elastic Form Factor Ratio at Low Q2
NASA Astrophysics Data System (ADS)
A high precision measurement of the proton elastic form factor ratio ?pGEp/GMp in the range Q2 = 0.3-0.7 GeV2/c2 was performed using recoil polarimetry in Jefferson Lab Hall A. In this low Q2 range, previous data from LEDEX [5] along with many fits and calculations [2, 3, 4] indicate substantial deviations of the ratio from unity. In this new measurement, with 80% polarized electron beam for 24 days, we are able to achieve <1% statistical uncertainty. Preliminary results are a few percent lower than expected from previous world data and fits, indicating a smaller GEp at this region. Beyond the intrinsic interest in nucleon structure, the improved form factor measurements also have implications for DVCS, determinations of the proton Zemach radius and strangeness form factors through parity violation experiments.
Zhan, Xiaohui
Calibration of the constants of high precision range-finder using unequal weight separation method
NASA Astrophysics Data System (ADS)
The additive constant C and multiplication constant R are two of the most important parameters for the corrections that are made to the measurements of electronic range-finder. The two parameters have direct influence on the correctness of measurements, and therefore are requisite for electronic range-finder calibration. In the paper firstly the operations of invar ruler contrast method as well as the determination of additive constant using simple analytical method were presented. Then based on the additive constant and the characteristics of the multiplication constant, the Unequal Weight Separation Method (UWSM) for separative calibration of the additive constant and the multiplication constant was put forward. The accuracy of UWSM was also analyzed, which was verified by processing data from multiple range-finders. Analysis showed that UWSM is easy to implement, reliable, and causes low intensity of workload, which is favorable to objectively assess the performance of high-precision of electronic range-finders.
Bao, Huan; Zhao, Dongming; Fu, Ziao; Zhu, Jiang; Gao, Zhan
The Use of Industrial Robot Arms for High Precision Patient Positioning
NASA Astrophysics Data System (ADS)
The Indiana University Cyclotron Facility (IUCF) is in the process of designing and building the Midwest Proton Radiation Institute (MPRI) [1]. The design process includes the development of several patient treatment systems. This paper discusses the use of two such systems that provide for the high precision positioning of a patient. They are the Patient Positioner System and the X-ray system. The Patient Positioner System positions an immobilized patient on a support device to a treatment position based on a prescribed Treatment Plan. The X-ray system uses an industrial robot arm to position a Digital Radiography Panel to acquire an X-ray image to verify the location of the prescribed treatment volume in a patient by comparing the acquired images with reference images obtained from the patient's Treatment plan.
Katuin, J. E.; Schreuder, A. N.; Starks, W. M.; Doskow, J.
Highly precise distributed Brillouin scattering sensor for structural health monitoring of optical ground wire cable
NASA Astrophysics Data System (ADS)
A distributed Brillouin scattering sensor with high special precision has been developed for the measurement of small damages/cracks of 1.5 cm. The out-layer damaged regions in an optical ground wire (OPGW) cable have been identified successfully by measuring the strain distributions every 5 cm using this technology. The stress increased to 127 kN which corresponds to more than 7500 micro-strain in the fibers. The locations of structural indentations comprising repaired and undamaged regions are found and distinguished using their corresponding strain data. The elongation of repaired region increases with time on 127 kN. These results are quantified in terms of the fiber orientation, stress, and behavior relative to undamaged sections.
Zou, Lufan; Ravet, Fabien; Bao, Xiaoyi; Chen, Liang
High precision U-Pb zircon ages for Mesozoic igneous rocks from Hong Kong
NASA Astrophysics Data System (ADS)
Sixteen new high precision U-Pb zircon ages are reported from Jurassic and Early Cretaceous silicic volcanic and plutonic rocks of Hong Kong. When combined with the existing age dataset, the new ages constrain more tightly the timing of major periods of volcanism and plutonism at 162.6 ▒ 4.5 Ma, 146.7 ▒ 1.1 Ma, 143.0 ▒ 1.0 Ma and 140.8 ▒ 0.6 Ma. However, two ages of 151.9 ▒ 0.2 Ma and 148.1 ▒ 0.2 Ma, from eastern New Territories and southern Hong Kong indicate additional and therefore more continuous, albeit pulsed, magmatic activity than previously thought.
Sewell, R. J.; Davis, D. W.; Campbell, S. D. G.
TRB3: a 264 channel high precision TDC platform and its applications
NASA Astrophysics Data System (ADS)
The TRB3 features four FPGA-based TDCs with < 20 ps RMS time precision between two channels and 256+4+4 channels in total. One central FPGA provides flexible trigger functionality and GbE connectivity including powerful slow control. We present recent users' applications of this platform following the COME&KISS principle: successful test beamtimes at CERN (CBM), in J³lich and Mainz with an FPGA-based discriminator board (PaDiWa), a charge-to-width FEE board with high dynamic range, read-out of the n-XYTER ASIC and software for data unpacking and TDC calibration in ROOT. We conclude with an outlook on future developments.
Neiser, A.; Adamczewski-Musch, J.; Hoek, M.; Koenig, W.; Korcyl, G.; Linev, S.; Maier, L.; Michel, J.; Palka, M.; Penschuck, M.; Traxler, M.; U?ur, C.; Zink, A.
High-precision gravimetric survey in support of lunar laser ranging at Haleakala, Maui, 1976 - 1978
NASA Technical Reports Server (NTRS)
The planning, observations and adjustment of high-precision gravity survey networks established on the islands of Maui and Oahu as part of the geodetic-geophysical program in support of lunar laser ranging at Haleakala, Maui, Hawaii are described. The gravity survey networks include 43 independently measured gravity differences along the gravity calibration line from Kahului Airport to the summit of Mt. Haleakala, together with some key points close to tidal gauges on Maui, and 40 gravity differences within metropolitan Honolulu. The results of the 1976-1978 survey are compared with surveys made in 1961 and in 1964-1965. All final gravity values are given in the system of the international gravity standardization net 1971 (IGSN 71); values are obtained by subtracting 14.57 mgal from the Potsdam value at the gravity base station at the Hickam Air Force Base, Honolulu.
Schenck, B. E.; Laurila, S. H.
High-precision microscopic phase imaging without phase unwrapping for cancer cell identification.
Experiments for cell identification are presented using a high-precision cell phase measurement system that does not require any phase unwrapping. This system is based on a Mach-Zehnder interferometer using a phase-locking technique, and it measures the change in optical path length while the sample is scanned across the optical axis. The spatial resolution is estimated to be less than 1.1Ā?m. The sensitivity of optical path length difference is estimated to be less than 2Ānm. Using experiments, we investigate the potential of this approach for cancer cell identification. In our preliminary experiments, cancer cells were distinguished from normal cells through comparison of optical path length differences. PMID:23595471
Watanabe, Eriko; Hoshiba, Takashi; Javidi, Bahram
LEBIT II: Upgrades and developments for high precision Penning trap mass measurements with rare isotopes
NASA Astrophysics Data System (ADS)
During the next several years and decades the extension of high-precision Penning trap mass spectrometry measurements to more-exotic isotopes, lying far from the valley of stability will continue to provide significant contributions to nuclear physics. However, such measurements must overcome the challenges of working with isotopes that have low production rates and short lifetimes. At the Low Energy Beam and Ion Trap (LEBIT) facility at the National Superconducting Cyclotron Laboratory, a number of developments have been implemented or are underway to meet these challenges by minimizing rare-isotope preparation and measurement time, maximizing use of available beam time, and increasing sensitivity. These developments and the current status of the LEBIT facility will be discussed.
Redshaw, M.; Bollen, G.; Bustabad, S.; Kwiatkowski, A. A.; Lincoln, D. L.; Novario, S. J.; Ringle, R.; Schwarz, S.; Valverde, A. A.
Nuclear reactions studied by quasi-elastic measurements with high precision at backward angles
NASA Astrophysics Data System (ADS)
The excitation functions of quasi-elastic scatterings at backward angles were measured with high precision to study the mechanisms of heavy-ion reactions at near- and sub-barrier energies. The surface diffuseness parameters for the 16O+144,152,154Sm, 170Er, 174Yb, 184,186W, 194,196Pt, and 208Pb systems have been extracted by the single-channel and coupled-channels calculations, respectively. No anomaly was found in these quasi-elastic processes. The barrier heights and barrier distributions were systematically investigated for these systems. Moreover, the coupled-channels effects of neutron transfers with positive Q-value and the breakup effects of weakly-bound nuclei on the fusion processes were also studied for the 32S+90,96Zr systems and the 6,7Li, 9Be+208Pb systems, respectively.
Lin, C. J.; Jia, H. M.; Zhang, H. Q.; Yang, F.; Xu, X. X.; Liu, Z. H.; Zhang, S. T.
New, High precision results on x>1 and the EMC Effect in Nuclei
NASA Astrophysics Data System (ADS)
Inclusive electron scattering has proven to be an exceptional tool for studying short range structure in nuclei. Measurements of the EMC effect at bjorken x < 1 are aimed at studying in-medium modification of the nucleon structure functions. On the other hand, inclusive measurements at bjorken x>1 focus on short range correlations (SRCs) between nucleons. Recent data on the EMC effect from Jefferson Lab suggest a sensitivity to short range nuclear structure related to NN correlations at x>1. The high precision results on the EMC effect and the ratios at x>1 have a linear relationship, suggesting a common physics explanation. Results from both experiments will be presented and plans for future measurements will be discussed.
Fomin, Nadia
Influence of sulfur-bearing polyatomic species on high precision measurements of Cu isotopic composition
An increased interest in high precision Cu isotope ratio measurements using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) has developed recently for various natural geologic systems and environmental applications, these typically contain high concentrations of sulfur, particularly in the form of sulfate (SO42-) and sulfide (S). For example, Cu, Fe, and Zn concentrations in acid mine drainage (AMD) can range from 100??g/L to greater than 50mg/L with sulfur species concentrations reaching greater than 1000mg/L. Routine separation of Cu, Fe and Zn from AMD, Cu-sulfide minerals and other geological matrices usually incorporates single anion exchange resin column chromatography for metal separation. During chromatographic separation, variable breakthrough of SO42- during anion exchange resin column chromatography into the Cu fractions was observed as a function of the initial sulfur to Cu ratio, column properties, and the sample matrix. SO42- present in the Cu fraction can form a polyatomic 32S-14N-16O-1H species causing a direct mass interference with 63Cu and producing artificially light ??65Cu values. Here we report the extent of the mass interference caused by SO42- breakthrough when measuring ??65Cu on natural samples and NIST SRM 976 Cu isotope spiked with SO42- after both single anion column chromatography and double anion column chromatography. A set of five 100??g/L Cu SRM 976 samples spiked with 500mg/L SO42- resulted in an average ??65Cu of -3.50?????5.42??? following single anion column separation with variable SO42- breakthrough but an average concentration of 770??g/L. Following double anion column separation, the average SO42-concentration of 13??g/L resulted in better precision and accuracy for the measured ??65Cu value of 0.01?????0.02??? relative to the expected 0??? for SRM 976. We conclude that attention to SO42- breakthrough on sulfur-rich samples is necessary for accurate and precise measurements of ??65Cu and may require the use of a double ion exchange column procedure. ?? 2010.
Pribil, M. J.; Wanty, R. B.; Ridley, W. I.; Borrok, D. M.
High-precision isotope ratio mass spectrometry and stable isotope precursors for tracer studies in cell culture.
The use of stable isotope-labeled tracers is demonstrated in an in vitro system with analysis by high-precision isotope ratio mass spectrometry (IRMS), using n-3 long-chain polyunsaturated fatty acid (LCP) biosynthesis from [U-(13)C]18:3n-3 (18:3n-3*) in Y79 human retinoblastoma cells as a model system. The cells were cultured as a suspension in RPMI 1640 medium supplemented with 15% fetal calf serum at 37 degrees C with 5% CO(2) in air. They were harvested by sedimentation and cell lipids were extracted to determine the presence of 18:3n-3* metabolites using gas chromatography-combustion (GCC)-IRMS. As the dose of 18:3n-3* was systematically increased from treatment to treatment, the atom percent excess and the amounts of biosynthesized LCP* increased, while the percentage dose in each n-3 LCP* remained constant. Cultures incubated with 0.5 micromol (10 microM) of albumin-bound 18:3n-3, composed of 18:3n-3* diluted 1/60 or 1/100 with natural abundance 18:3n-3, yielded products with enrichments about 1.5 at.% excess (delta(13)C(PDB) < 1500 per thousand), which is optimal for high-precision measurements. Kinetics in Y79 cells incubated with 18:3n-3* showed that n-3 LCP* incorporation increased over time; 18:3n-3*, 20:5n-3*, 22:5n-3*, and 22:6n-3* were detected at all time points with the 1/60 dilution. These data document experimental parameters for optimal stable isotope use and IRMS detection for in vitro tracer methodology. PMID:11078586
Huang, M C; Muddana, S; Horowitz, E N; McCormick, C C; Infante, J P; Brenna, J T
A high-precision five-degree-of-freedom measurement system based on laser collimator and interferometry techniques.
A novel sensitivity improving method for simultaneously measuring five-degree-of-freedom errors of a moving linear stage is proposed based on collimator and interferometry techniques. The measuring principle and parameters of the system are analyzed theoretically. The experimental results proved that the resolution of the linear displacement of the proposed method has twice that of the current linear interferometer, and the resolutions of the two-dimensional straightness error measurement can be improved by a factor of 8 compared with the movement of the retroreflector itself by using multireflection and lens magnification. The resolutions of the pitch and yaw angular error measurement have been improved by a factor of 10 compared with the rotation of the plane mirror itself by using expander lenses. The whole measuring system is characterized of simple structure, small volume, and high precision. The moving component of the measurement system is wireless, which eliminates the errors and inconvenience introduced by the wire connection. Calibration and comparison tests of this system compared with Renishaw laser interferometer system have been carried out. Experimental results show good consistency for measuring a linear guide way. PMID:17902972
Kuang, Cuifang; Hong, En; Ni, Jun
A high-precision five-degree-of-freedom measurement system based on laser collimator and interferometry techniques
A novel sensitivity improving method for simultaneously measuring five-degree-of-freedom errors of a moving linear stage is proposed based on collimator and interferometry techniques. The measuring principle and parameters of the system are analyzed theoretically. The experimental results proved that the resolution of the linear displacement of the proposed method has twice that of the current linear interferometer, and the resolutions of the two-dimensional straightness error measurement can be improved by a factor of 8 compared with the movement of the retroreflector itself by using multireflection and lens magnification. The resolutions of the pitch and yaw angular error measurement have been improved by a factor of 10 compared with the rotation of the plane mirror itself by using expander lenses. The whole measuring system is characterized of simple structure, small volume, and high precision. The moving component of the measurement system is wireless, which eliminates the errors and inconvenience introduced by the wire connection. Calibration and comparison tests of this system compared with Renishaw laser interferometer system have been carried out. Experimental results show good consistency for measuring a linear guide way.
Kuang Cuifang; Hong En; Ni Jun [School of Information Science and Technology, Beijing Institute of Technology, Beijing 100081 (China); Mechanical Engineering Department, University of Michigan, Ann Arbor, Michigan 48109-2125 (United States)
Achieving high-precision pointing on ExoplanetSat: initial feasibility analysis
NASA Astrophysics Data System (ADS)
ExoplanetSat is a proposed three-unit CubeSat designed to detect down to Earth-sized exoplanets in an orbit out to the habitable zone of Sun-like stars via the transit method. To achieve the required photometric precision to make these measurements, the target star must remain within the same fraction of a pixel, which is equivalent to controlling the pointing of the satellite to the arcsecond level. The satellite will use a two-stage control system: coarse control will be performed by a set of reaction wheels, desaturated by magnetic torque coils, and fine control will be performed by a piezoelectric translation stage. Since no satellite of this size has previously demonstrated this high level of pointing precision, a simulation has been developed to prove the feasibility of realizing such a system. The current baseline simulation has demonstrated the ability to hold the target star to within 0.05 pixels or 1.8 arcseconds (with an 85 mm lens and 15 ?m pixels), in the presence of large reaction wheel disturbances as well as external environmental disturbances. This meets the current requirement of holding the target star to 0.14 pixels or 5.0 arcseconds. Other high-risk aspects of the design have been analyzed such as the effect of changing the guide star centroiding error, changing the CMOS sampling frequency, and reaction wheel selection on the slew performance of the satellite. While these results are promising as an initial feasibility analysis, further model improvements and hardware-in-the-loop tests are currently underway.
Pong, Christopher M.; Lim, Sungyung; Smith, Matthew W.; Miller, David W.; Villase±or, Jesus S.; Seager, Sara
[Anterior high frequency capsulotomy. I. Experimental study].
Basing on the bipolar-coaxial wetfield-diathermy, introduced in microsurgery 1974 by the author, an anterior capsulotomy instrument using a modulated RF-current was published in 1984. In the meantime several patients have been operated successfully with this technique. However, further experimental studies allowed a refining of the instrument, an improvement of the electronic control device and a perfection of the surgical technique. Today, this technique has four considerable advantages compared with other methods: the size of the capsulotomy opening is not casual but determined by the surgeon, the presence of a viscous substance in the anterior chamber definitely facilitates the optical control of the surgical procedure, the border of the capsulotomy is astonishingly resistant to mechanical forces, therefore the risk of radial capsular tears is highly reduced, the border of the capsulotomy is well defined by a tiny grayish coagulation line which facilitates the implantation. The experimental results are demonstrated. The clinical and surgical results are presented in the same journal by Coester et al. PMID:1614140
Kl÷ti, R
Correlated cryo-fluorescence and cryo-electron microscopy with high spatial precision and improved sensitivity.
Performing fluorescence microscopy and electron microscopy on the same sample allows fluorescent signals to be used to identify and locate features of interest for subsequent imaging by electron microscopy. To carry out such correlative microscopy on vitrified samples appropriate for structural cryo-electron microscopy it is necessary to perform fluorescence microscopy at liquid-nitrogen temperatures. Here we describe an adaptation of a cryo-light microscopy stage to permit use of high-numerical aperture objectives. This allows high-sensitivity and high-resolution fluorescence microscopy of vitrified samples. We describe and apply a correlative cryo-fluorescence and cryo-electron microscopy workflow together with a fiducial bead-based image correlation procedure. This procedure allows us to locate fluorescent bacteriophages in cryo-electron microscopy images with an accuracy on the order of 50 nm, based on their fluorescent signal. It will allow the user to precisely and unambiguously identify and locate objects and events for subsequent high-resolution structural study, based on fluorescent signals. PMID:24275379
Schorb, Martin; Briggs, John A G
HPMSS(High Precision Magnetic Survey System) and InterRidge
NASA Astrophysics Data System (ADS)
From the beginning of 1990s to the beginning of 2000s, the Japanese group of IntreRidge conducted many cruises for three component magnetic survey using Shipboard Three Component Magnetometer (STCM) and Deep Towed Three Component Magnetometer (DTCM) in the world wide oceans. We have been developing HPMSS during this time with support of Dr.Tamaki(the late representative of InterRidge Japan) who understood the advantages of three component geomagnetic anomalies (TCGA). TCGA measured by STCM determines the direction of geomagnetic anomaly lineations precisely at every point where TCGA were observed, which playes the important role in magnetic anomaly lineation analysis. Even in the beginning of 2000s, almost all marine magnetic scientists believed that the total intensity anomly (TIA) is the better data than TCGA for analysis because the scalar magnetometers (e.g. proton precession magnetometer) have the better accuracy than any other magnetometers (e.g.flux gate magnetometer (FGM)). We employed the high accrate gyroscope (e.g.ring lase gyroscope (RLG)/optical fiber gyroscope (OFG)) to improve the accuracy of STCM/DTCM equipped with FGM. Moreover we employed accurate and precise FGM which was selected among the market. Finally we developed the new magnetic survey system with high precision usable as airborn, shipboard and dee-ptowed magnetometers which we call HPMSS(High Precision Magnetic Survey System). As an optional equipment, we use LAN to communicate between a data aquisiitin part and a data logging part, and GPS for a position fix. For the deep-towed survey, we use the acoustic position fix (super short base line method) and the acoustic communication to monitor the DTCM status. First we used HPMSS to obtain the magnetization structure of the volcanic island, Aogashima located 300km south of Tokyo using a hellcopter in 2006 and 2009. Next we used HPMSS installed in DTCM in 2010,2011 and 2012 using R/V Bosei-maru belonging to Tokai University. Also we used HPMSS installed in AUV (automonous undersea vehicle), belonging to JAMSTEC in 2009,2010 and 2011. We have been emphasizing the importnace of TCGA compared to TIA because TIA does not obey the Laplace equation which means TIA is not harmonic, then we cannot apply the Fourier analysis on TIA. We will show the structure of three component magnetization of the mineral deposit in the volcanic thermal area in Izu-Ogasawara island Arc, called Hakurei Deposit. TCGA of DTCM and AUV survey data were used and the depth section and the vertical section of three components of magnetization of Hakurei Deposit area will be presented. We emphasize that reliable 3D structure of three component of magnetization was obtained from TCGA using HPMSS as the result of deep support of InterRidge Japan, especially deep support of Dr. Tamaki.
Isezaki, N.; Sayanagi, K.
High-precision molecular dynamics simulation of UO2-PuO2: Anion self-diffusion in UO2
NASA Astrophysics Data System (ADS)
Our series of articles is devoted to high-precision molecular dynamics simulation of mixed actinide-oxide (MOX) fuel in the approximation of rigid ions and pair interactions (RIPI) using high-performance graphics processors (GPU). In this article we study self-diffusion mechanisms of oxygen anions in uranium dioxide (UO2) with the 10 recent and widely used sets of interatomic pair potentials (SPP) under periodic (PBC) and isolated (IBC) boundary conditions. Wide range of measured diffusion coefficients (from 10-3 cm2/s at melting point down to 10-12 cm2/s at 1400 K) made possible a direct comparison (without extrapolation) of the simulation results with the experimental data, which have been known only at low temperatures (T < 1500 K). A highly detailed (with the temperature step of 1 K) calculation of the diffusion coefficient allowed us to plot temperature dependences of the diffusion activation energy and its derivative, both of which show a wide (ś1000 K) superionic transition region confirming the broad ?-peaks of heat capacity obtained by us earlier. It is shown that regardless of SPP the anion self-diffusion in model crystals without surface or artificially embedded defects goes on via exchange mechanism, rather than interstitial or vacancy mechanisms suggested by the previous works. The activation energy of exchange diffusion turned out to coincide with the anti-Frenkel defect formation energy calculated by the lattice statics.
Potashnikov, S. I.; Boyarchenkov, A. S.; Nekrasov, K. A.; Kupryazhkin, A. Ya.
Sensor for high speed, high precision measurement of 2-d positions.
A sensor system to measure the 2-D position of an object that intercepts a plane in space is presented in this paper. This sensor system was developed with the aim of measuring the height and lateral position of contact wires supplying power to electric locomotives. The sensor comprises two line-scans focused on the zone to be measured and positioned in such a way that their viewing planes are on the same plane. The report includes a mathematical model of the sensor system, and details the method used for calibrating the sensor system. The procedure used for high speed measurement of object position in space is also described, where measurement acquisition time was less than 0.7 ms. Finally, position measurement results verifying system performance in real time are given. PMID:22291537
Luna, Carlos A; Lßzaro, Josķ L; Mazo, Manuel; Cano, Angel
High-Precision Measurement of the Ne19 Half-Life and Implications for Right-Handed Weak Currents
NASA Astrophysics Data System (ADS)
We report a precise determination of the Ne19 half-life to be T1/2=17.262▒0.007s. This result disagrees with the most recent precision measurements and is important for placing bounds on predicted right-handed interactions that are absent in the current standard model. We are able to identify and disentangle two competing systematic effects that influence the accuracy of such measurements. Our findings prompt a reassessment of results from previous high-precision lifetime measurements that used similar equipment and methods.
Triambak, S.; Finlay, P.; Sumithrarachchi, C. S.; Hackman, G.; Ball, G. C.; Garrett, P. E.; Svensson, C. E.; Cross, D. S.; Garnsworthy, A. B.; Kshetri, R.; Orce, J. N.; Pearson, M. R.; Tardiff, E. R.; Al-Falou, H.; Austin, R. A. E.; Churchman, R.; Djongolov, M. K.; D'Entremont, R.; Kierans, C.; Milovanovic, L.; O'Hagan, S.; Reeve, S.; Sjue, S. K. L.; Williams, S. J.
Sensitivity studies of high-precision methane column concentration inversion using a line-by-line radiative transfer model
NASA Astrophysics Data System (ADS)
Hyper-spectral remote sensing may provide an effective solution to retrieve the methane (CH4) concentration in an atmospheric column. As a result of exploring the absorptive characteristics of CH4, an appropriate band is selected from hyperspectral data for the detection of its column concentration with high precision. Following the most recent inversion theory and methods, the line-by-line radiative transfer model (LBLRTM) is employed to forward model the impact of four sensitive factors on inversion precision, including CH4 initial profile, temperature, overlapping gases, and surface albedo. The results indicate that the four optimized factors could improve the inversion precision of atmospheric CH4 column concentration.
Song, Ci; Shu, Jiong; Zhou, Mandi; Gao, Wei
QCD Precision Measurements and Structure Function Extraction at a High Statistics, High Energy Neutrino Scattering Experiment: NuSOnG
We extend the physics case for a new high-energy, ultra-high statistics neutrino scattering experiment, NuSOnG (Neutrino Scattering On Glass) to address a variety of issues including precision QCD measurements, extraction of structure functions, and the derived Parton Distribution Functions (PDFs). This experiment uses a Tevatron-based neutrino beam to obtain a sample of Deep Inelastic Scattering (DIS) events which is over two orders of magnitude larger than past samples. We outline an innovative method for fitting the structure functions using a parameterized energy shift which yields reduced systematic uncertainties. High statistics measurements, in combination with improved systematics, will enable NuSOnG to perform discerning tests of fundamental Standard Model parameters as we search for deviations which may hint of 'Beyond the Standard Model' physics.
Adams, T.; /Florida State U.; Batra, P.; /Columbia U.; Bugel, Leonard G.; /Columbia U.; Camilleri, Leslie Loris; /Columbia U.; Conrad, Janet Marie; /MIT; de Gouvea, A.; /Northwestern U.; Fisher, Peter H.; /MIT; Formaggio, Joseph Angelo; /MIT; Jenkins, J.; /Northwestern U.; Karagiorgi, Georgia S.; /MIT; Kobilarcik, T.R.; /Fermilab /Texas U.
New technology enables high precision multislit collimators for microbeam radiation therapy
During the past decade microbeam radiation therapy has evolved from preclinical studies to a stage in which clinical trials can be planned, using spatially fractionated, highly collimated and high intensity beams like those generated at the x-ray ID17 beamline of the European Synchrotron Radiation Facility. The production of such microbeams typically between 25 and 100 {mu}m full width at half maximum (FWHM) values and 100-400 {mu}m center-to-center (c-t-c) spacings requires a multislit collimator either with fixed or adjustable microbeam width. The mechanical regularity of such devices is the most important property required to produce an array of identical microbeams. That ensures treatment reproducibility and reliable use of Monte Carlo-based treatment planning systems. New high precision wire cutting techniques allow the fabrication of these collimators made of tungsten carbide. We present a variable slit width collimator as well as a single slit device with a fixed setting of 50 {mu}m FWHM and 400 {mu}m c-t-c, both able to cover irradiation fields of 50 mm width, deemed to meet clinical requirements. Important improvements have reduced the standard deviation of 5.5 {mu}m to less than 1 {mu}m for a nominal FWHM value of 25 {mu}m. The specifications of both devices, the methods used to measure these characteristics, and the results are presented.
Braeuer-Krisch, E.; Requardt, H.; Brochard, T.; Berruyer, G.; Renier, M.; Bravin, A. [European Synchrotron Radiation Facility, B.P. 220, 38043 Grenoble (France); Laissue, J. A. [Institute of Pathology, University of Bern, Murtenstrasse 31, 3010 Bern (Switzerland)
Project GeoWSN: High precision but low-cost GNSS landslide monitoring in Austria
NASA Astrophysics Data System (ADS)
At present, GNSS monitoring of landslides is an accepted and approved method to detect movements of slopes at risk in the sub-centimetre level. However, high-precision geodetic GNSS-receivers are expensive, therefore this monitoring method is not widely applied. Recently low-cost GNSS-receivers are conquering the geodetic market and are well suited for a cost effective and yet precise GNSS-monitoring. During the project GeoWSN, which was funded by the Austrian Research Promotion Agency (FFG), an applicable low-cost monitoring system was developed at Graz University of Technology. The system is based on a so-called Wireless Sensor Network (WSN) consisting of low-cost GNSS-receivers, temperature and humidity sensors and inertial measurement units. Additionally energy-harvesting technologies and power-saving algorithms provide that the system is energy- autarkic. For real-time applications, a communication link between the sensor nodes is implemented. The relative positioning method RTK (Real Time Kinematic) is applied to reach the highest possible accuracy. The GeoWSN sensor nodes enable the detection of possible movements in the real-time processed positions of the sensor nodes. To ensure a real-time evaluation and interpretation of the data, the current status of the slope can be acquired by a local warning centre. Therefore, affected people can be warned within a short latency. Several test-scenarios have shown the acceptance of the system at the warning centre of Styria, Austria. This contribution should give an overview of the main idea of a low-cost warning system and results of the project GeoWSN.
Koch, Daniel; Brandstõtter, Michael; K³htreiber, Norbert
High-Precision CTE Measurement of SiC-100 for Cryogenic Space Telescopes
NASA Astrophysics Data System (ADS)
We present the results of high-precision measurements of the thermal expansion of sintered SiC, SiC-100, intended for use in cryogenic space telescopes, in which minimization of thermal deformation of the mirror is critical, and precise information of the thermal expansion is needed for the telescope design. The temperature range of the measurements extends from room temperature down to ~10 K. Three samples, Nos. 1, 2, and 3, were manufactured from blocks of SiC produced in different lots. The thermal expansion of the samples was measured with a cryogenic dilatometer, consisting of a laser interferometer, a cryostat, and a mechanical cooler. The typical thermal expansion curve is presented using an eighth-order polynomial of the temperature. For the three samples, the coefficients of thermal expansion (CTE), ?»1, ?»2, and ?»3, were derived for temperatures between 293 and 10 K. The average and the dispersion (1 ? rms) of these three CTEs are 0.816 ū 10-6 and 0.002 ū 10-6 K-1, respectively. No significant difference was detected in the CTE of the three samples from the different lots. Neither inhomogeneity nor anisotropy of the CTE was observed. Based on the CTE dispersion obtained, we performed a finite-element method (FEM) analysis of the thermal deformation of a 3.5 m diameter cryogenic mirror made of six SiC-100 segments. It was shown that the present CTE measurement has an accuracy that is sufficient for the design of the 3.5 m cryogenic infrared telescope mission SPICA (Space Infrared Telescope for Cosmology and Astrophysics).
Enya, K.; Yamada, N.; Onaka, T.; Nakagawa, T.; Kaneda, H.; Hirabayashi, M.; Toulemont, Y.; Castel, D.; Kanai, Y.; Fujishiro, N.
Ultra-high-precision alignment technology for lens manufacturing used for high-end optics
NASA Astrophysics Data System (ADS)
This article describes the progress in the area of modern centration technology by using digital image processing. This work is motivated by the continuously increasing demand for high-end optics. During the last years the surface lens quality has been continuously improved. Today the image quality is more determined by the manufacturing tolerances for the mechanical interface which is responsible for decenter and tilt of the lenses respectively the subgroups. Some of the aberrations are directly linked to the decenter of the lenses, Coma for example. Hence it is necessary to realize the subgroups with tolerances below lpm. To determine the decenter of a lens an auto collimation telescope is used to image the reflex of the lens surfaces onto a detector, commonly a half covert photodiode. Rotating the lens generates a sinusoidal signal, which is evaluated by a lock-in amplifier to drive two actuators to adjust the alignment chuck. Typical internal reflections caused by stray light for example disturb the current procedure in such a way that it is impossible to get a stable alignment process. Digital image processing allows us to fix these problems with image recognition. We will demonstrate how a modified auto collimation telescope in combination with the developed software algorithms made the manufacturing process more accurate, faster and useable for a broad spectrum of lenses. It has been proofed by some thousand diverse lenses that with these new technique subgroups can be centered within 0.25?m.
Schiffner, Sebastian; Sure, Thomas
Theoretical and experimental research on error analysis and optimization of tool path in fabricating aspheric compound eyes by precision micro milling
NASA Astrophysics Data System (ADS)
Structure design and fabricating methods of three-dimensional (3D) artificial spherical compound eyes have been researched by many scholars. Micro-nano optical manufacturing is mostly used to process 3D artificial compound eyes. However, spherical optical compound eyes are less at optical performance than the eyes of insects, and it is difficult to further improve the imaging quality of compound eyes by means of micro-nano optical manufacturing. In this research, nonhomogeneous aspheric compound eyes (ACEs) are designed and fabricated. The nonhomogeneous aspheric structure is applied to calibrate the spherical aberration. Micro milling with advantages in processing three-dimensional micro structures is adopted to manufacture ACEs. In order to obtain ACEs with high imaging quality, the tool paths are optimized by analyzing the influence factors consisting of interpolation allowable error, scallop height and tool path pattern. In the experiments, two kinds of ACEs are manufactured by micro-milling with different too path patterns and cutting parameter on the miniature precision five-axis milling machine tool. The experimental results indicate that the ACEs of high surface quality can be achieved by circularly milling small micro-lens individually with changeable cutting depth. A prototype of the aspheric compound eye (ACE) with surface roughness ( R a) below 0.12 ?m is obtained with good imaging performance. This research ameliorates the imaging quality of 3D artificial compound eyes, and the proposed method of micro-milling can improve surface processing quality of compound eyes.
Chen, Mingjun; Xiao, Yong; Tian, Wenlan; Wu, Chunya; Chu, Xin
Towards establishing high-precision 40Ar/39Ar chronologies for distal tephra archives
NASA Astrophysics Data System (ADS)
To develop further understanding of palaeoclimate change in a context of, for example, the expansion of hominin out of Africa and abrupt climate change, correlation between high-resolution terrestrial, marine and ice core archives from around the globe is key. Whereas there can be significant uncertainties in the tuning of palaeoclimate proxy records (i.e., wiggle matching) between regions, direct tephra correlations have essentially zero uncertainty, providing the correlations are robust. Tephrochronology has demonstrated tremendous potential for correlation of records across regions and construction of relative chronological tephra matrices. However absolute dating is often required for: (1) pinning of events to the geological timescale; and (2) to confirm the validity of correlations if geochemical fingerprints do not prove to be definitive. 14C dating can be used for radiocarbon-bearing sediments within which volcanic tephra are intercalated. However, the technique only extends over the last 50 ka and precision suffers dramatically with increasing age. The technique is reliant on the availability of radiocarbon-bearing material within sediments and direct comparison of 14C chronologies from marine and terrestrial settings is problematic owing to marine reservoir offset. OSL dating can also be used to date sediments above and below tephra units but uncertainties are typically too large for development of high-precision chronologies. Volcanic K-bearing distal tephra can theoretically be dated using the 40Ar/39Ar technique thereby placing direct temporal constraints on palaeoclimate records. However, in reality, distal tephra are usually fine-grained and crystal-poor, lacking mineral phases amenable to 40Ar/39Ar dating of young rocks, e.g., sanidine. Although the distal samples contain abundant K-bearing glass shards, they have been shown to provide unreliable 40Ar/39Ar ages likely due to a combination of post eruption K-loss (during glass hydration?) and 37Ar and 39Ar recoil effects. These effects are amplified by a high surface area to volume ratio of glass shards and thus short effective diffusion dimensions (radii of glass shards). I will discuss the application of 40Ar/39Ar geochronology to distal tephra and present two methodologies for establishing absolute 40Ar/39Ar age constraints for distal tephra archives. Two case studies will be presented: [1] dating of distal tephra in Lake Suigetsu, Japan by establishing robust correlations between proximal (crystal-rich) and distal (crystal-poor) volcanic deposits, and [2] dating of distal Toba tephra throughout peninsular of India by targeting of sub-100 ?m shards of biotite. A look at future development in 40Ar/39Ar geochronology and noble gas mass spectrometry with implications for tephrochronology studies will conclude the presentation.
Mark, D. F.
Ninetyeast Ridge, KNOX06RR: High-Precision Isotopic Compositions From New Dredge Samples
NASA Astrophysics Data System (ADS)
The Ninetyeast Ridge (NER), the longest linear feature on Earth (~5000 km), corresponds to ~44 Myr of evolution of the Indian Ocean basin related to the Kerguelen mantle plume. Almost two decades after its basement was successfully drilled during ODP Leg 121, the NER was the scientific destination of an NSF- funded cruise during the summer of 2007. One of the scientific objectives of this research cruise was to dredge several sites along the ridge to recover suitable igneous basement rocks for geochemical and geochronological analyses, and use these new data to re-examine and test the models proposed for the magmatic origin of the ridge. Basaltic basement was recovered in 23 of the total 33 dredges that spanned ~3000 km of the NER. We present high-precision isotopic compositions by MC-ICP-MS (Pb, Hf, and Nd) and TIMS (Sr) obtained on basalts from 10 of the dredges, selected to sample most of the ridge length. The 27 basalts were chosen based on their lowest alteration degree (lowest LOI), high Mg#, and variable trace element ratios (e.g. Zr/Nb, Y/Nb, La/Sm). The dredged samples analyzed to date yield wider within-site isotopic variability compared to high-precision analyses of the previously drilled samples (Nobre Silva et al., Goldschmidt 2006 & 2007). The isotopic compositions of the dredge samples are consistent with contributions from the Kerguelen, Amsterdam and St. Paul mantle plumes to the origin of the NER basalts. Additionally, the dredge samples now extend the isotopic range of the NER to Indian MORB compositions, as samples collected in dredges located at basal scarps along the edge of the ridge and the seafloor (e.g. dredges 3, 4, 16 and 33) fall along mixing lines (in Pb-Pb, Sr-Pb, Nd-Pb, Hf-Pb spaces) between the enriched St. Paul and Kerguelen mantle plumes with depleted Indian MORB. Further isotopic results on the remaining dredge samples will allow us to better constrain the mixing relationship of the Kerguelen, Amsterdam and St. Paul mantle plumes with Indian MORB, as well as improve our understanding of the magmatic and tectonic history of the Indian Ocean basin.
Nobre Silva, I.; Weis, D.; Scoates, J. S.; Frey, F. A.
High Precision and High Sensitivity Measurements of Osmium Isotopes in Natural Waters
NASA Astrophysics Data System (ADS)
Direct measurements of Os in water are critical in understanding the geochemical cycle of Os in the environment. However, measurements of Os isotopes in natural waters are challenging due to a) low concentrations (~10 fg/g or less; 1 fg/g = 10-15 g/g) and b) the differences in oxidation states of naturally occurring and tracer Os that prevent accurate determination of Os concentration by isotope dilution [Sharma et al., GCA 61:5411, 1997]. It has been recognized for more than a decade that the best way to chemically separate and purify Os and at the same time achieve tracer-sample equilibration is to oxidize Os in sample-tracer mixture to OsO4. Three techniques have been developed: 1) heating of sample-tracer mixture with Br2 and Cr6+ in Teflon bombs at 90░C and solvent-extraction of OsO4 with Br2 [Levasseur et al., Science 282:272, 1998]; 2) heating to 180░C with Cr6+ in sealed glass (carius) tubes and its extraction by distillation [Sharma et al., GCA 63:4005, 1999]; 3) heating of water in the presence of H2O2 and H2SO4 and distillation of OsO4 [Woodhouse et al., EPSL 173:223, 1999]. The blanks for these techniques are [Os] = 22 fg 187Os/188Os = 0.47, [Os] = 19 fg 187Os/188Os = 0.27, and [Os] = 120 fg 187Os/188Os = 0.31, respectively. We have modified the carius tube technique by using a High Pressure Asher at 300░C and a confining pressure of 100 bars. This method is an improvement over previous techniques because the time required to achieve complete oxidation is much shorter due to the increased temperature of reaction and the blanks are significantly lower ([Os] = 2.2 fg, 187Os/188Os = 0.18) due to smaller amounts of reagents used. Additionally, we have modified the mass spectrometry associated with measuring low level Os samples. Typically, Os is measured on a single Pt filament as OsO3-, but we have modified the technique to include a double filament geometry. We use Ta for the ionization filament and Pt for the evaporation filament. The double filament geometry allows us to run samples at a lower temperature, thus reducing the blank contribution from the Pt filament. Not only do we find total Re counts to be reduced, but organic interferences on mass 233 (185Re.16O4-) are no longer present, allowing for more accurate Re correction. Repeated measurements of a 200 fg standard gives 2? uncertainty of 1.38% for 187Os/188Os and 0.32% for 190Os/188Os. The improvements in chemistry and mass spectrometry allow the analysis of low level water samples such as snow from Antarctica and to understand the transport of Os from atmosphere to the oceans. We have applied this technique to surface and deep seawater samples collected from the Atlantic Ocean through GEOTRACES (Summer '08) and find that the surface seawater has been impacted by inputs of anthropogenic Os.
Chen, C.; Sharma, M.
High-precision topography measurement through accurate in-focus plane detection with hybrid digital holographic microscope and white light interferometer module.
High-precision topography measurement of micro-objects using interferometric and holographic techniques can be realized provided that the in-focus plane of an imaging system is very accurately determined. Therefore, in this paper we propose an accurate technique for in-focus plane determination, which is based on coherent and incoherent light. The proposed method consists of two major steps. First, a calibration of the imaging system with an amplitude object is performed with a common autofocusing method using coherent illumination, which allows for accurate localization of the in-focus plane position. In the second step, the position of the detected in-focus plane with respect to the imaging system is measured with white light interferometry. The obtained distance is used to accurately adjust a sample with the precision required for the measurement. The experimental validation of the proposed method is given for measurement of high-numerical-aperture microlenses with subwavelength accuracy. PMID:24787417
Li?ewski, Kamil; Tomczewski, S?awomir; Kozacki, Tomasz; Kostencka, Julianna
Optomechanical design of a high-precision detector robot arm system for x-ray nano-diffraction with x-ray nanoprobe
NASA Astrophysics Data System (ADS)
Collaboration between Argonne National Laboratory and Brookhaven National Laboratory has created a design for the high-precision detector robot arm system that will be used in the x-ray nano-diffraction experimental station at the Hard X-ray Nanoprobe (HXN) beamline for the NSLS-II project. The robot arm system is designed for positioning and manipulating an x-ray detector in three-dimensional space for nano-diffraction data acquisition with the HXN x-ray microscope. It consists of the following major component groups: a granite base with air-bearing support, a 2-D horizontal base stage, a vertical axis goniometer, a 2-D vertical plane robot arm, a 3-D fast scanning stages group, and a 2-D x-ray pixel detector. The design specifications and unique optomechanical structure of this novel high-precision detector robot arm system will be presented in this paper.
Shu, D.; Kalbfleisch, S.; Kearney, S.; Anton, J.; Chu, Y. S.
High-precision tracking of sperm swimming fine structure provides strong test of resistive force theory.
The shape of the flagellar beat determines the path along which a sperm cell swims. If the flagellum bends periodically about a curved mean shape then the sperm will follow a path with non-zero curvature. To test a simple hydrodynamic theory of flagellar propulsion known as resistive force theory, we conducted high-precision measurements of the head and flagellum motions during circular swimming of bull spermatozoa near a surface. We found that the fine structure of sperm swimming represented by the rapid wiggling of the sperm head around an averaged path is, to high accuracy, accounted for by resistive force theory and results from balancing forces and torques generated by the beating flagellum. We determined the anisotropy ratio between the normal and tangential hydrodynamic friction coefficients of the flagellum to be 1.81+/-0.07 (mean+/-s.d.). On time scales longer than the flagellar beat cycle, sperm cells followed circular paths of non-zero curvature. Our data show that path curvature is approximately equal to twice the average curvature of the flagellum, consistent with quantitative predictions of resistive force theory. Hence, this theory accurately predicts the complex trajectories of sperm cells from the detailed shape of their flagellar beat across different time scales. PMID:20348333
Friedrich, B M; Riedel-Kruse, I H; Howard, J; J³licher, F
High Precision UV Measurements in CO, Towards a Laboratory Test of the Time-Invariance of ?.
NASA Astrophysics Data System (ADS)
The metastable a^3? state of CO has favourable properties for testing the time-invariance of physical constants. Due to an incidental near-degeneracy between the ?=0, J=8 and the ?=0, J=6 the 2-photon microwave transition connecting these two states is highly sensitive to a possible time variation of physical constants, with a sensitivity coefficient ranging from ? -300 to ? +150 for different isotopes. We are planning a molecular beam experiment to measure these transitions. As a first step, spectroscopic measurements have been performed on the X^1?^+ ? a^3? transition around 206 nm. We have recorded a total of 40 optical transitions in the six most abundant isotopes. For these measurements, we have used the fourth harmonic of an injection-seeded titanium:sapphire pulsed oscillator. A frequency comb laser referenced to a Rb-clock was used for the absolute calibration of the seed laser. An absolute accuracy of a few MHz was reached. The optical data for 12C16O, together with published RF and MW data, was fitted to an effective Hamiltonian. The precision of a number of molecular parameters was significantly increased. The obtained parameters were isotope scaled to calculate the optical transition frequencies in other isotopes. These frequencies typically agree with the measurements within 10 MHz. These calculations confirm the high sensitivity of the near degeneracies to variations of ?. H.L. Bethlem and W. Ubachs, Faraday Discussions 142, 25-36 (2009)
de Nijs, Adrian J.; Eikema, Kjeld S. E.; Ubachs, Wim; Bethlem, Hendrick L.
New high-precision measurements of the isotopic composition of atmospheric argon
NASA Astrophysics Data System (ADS)
Earth's atmosphere is used as a standard reference gas for mass spectrometric determinations of argon (Ar) isotopes used principally in geochronology. There are three published independent determinations of the Ar isotope composition of modern atmosphere that differ subtly. We have made new high-precision measurements of Ar isotope ratios of five different sources of air using a high-sensitivity multi-collector noble gas mass spectrometer in order to distinguish between them. The isotope ratios, corrected only for backgrounds, reside on a inverse square-root mass law fractionation line that passes through the air value proposed by Lee et al. [Lee J. Y., Marti K., Severinghaus J. P., Kawamura K., Yoo H. S., Lee J. B. and Kim J. S. (2006) A redetermination of the isotopic abundances of atmospheric Ar. Geochim. Cosmochim. Acta70, 4507-4512]. They are distinct from both the other proposed compositions and provide the first independent confirmation of the atmospheric Ar isotope composition. We suggest that the revised values should now be in routine employment.
Mark, D. F.; Stuart, F. M.; de Podesta, M.
The Spring 1985 high precision baseline test of the JPL GPS-based geodetic system
NASA Technical Reports Server (NTRS)
The Spring 1985 High Precision Baseline Test (HPBT) was conducted. The HPBT was designed to meet a number of objectives. Foremost among these was the demonstration of a level of accuracy of 1 to 2:10 to the 7th power, or better, for baselines ranging in length up to several hundred kilometers. These objectives were all met with a high degree of success, with respect to the demonstration of system accuracy in particular. The results from six baselines ranging in length from 70 to 729 km were examined for repeatability and, in the case of three baselines, were compared to results from colocated VLBI systems. Repeatability was found to be 5:10 to the 8th power (RMS) for the north baseline coordinate, independent of baseline length, while for the east coordinate RMS repeatability was found to be larger than this by factors of 2 to 4. The GPS-based results were found to be in agreement with those from colocated VLBI measurements, when corrected for the physical separations of the VLBI and CPG antennas, at the level of 1 to 2:10 to the 7th power in all coordinates, independent of baseline length. The results for baseline repeatability are consistent with the current GPA error budget, but the GPS-VLBI intercomparisons disagree at a somewhat larger level than expected. It is hypothesized that these differences may result from errors in the local survey measurements used to correct for the separations of the GPS and VLBI antenna reference centers.
Davidson, John M.; Thornton, Catherine L.; Stephens, Scott A.; Blewitt, Geoffrey; Lichten, Stephen M.; Sovers, Ojars J.; Kroger, Peter M.; Skrumeda, Lisa L.; Border, James S.; Neilan, Ruth E.
Precise detection of L. monocytogenes hitting its highly conserved region possessing several specific antibody binding sites.
Listeria monocytogenes, a facultative intracellular fast-growing Gram-positive food-borne pathogen, can infect immunocompromised individuals leading to meningitis, meningoencephalitis and septicaemias. From the pool of virulence factors of the organism, ActA, a membrane protein, has a critical role in the life cycle of L. monocytogenes. High mortality rate of listeriosis necessitates a sensitive and rapid diagnostic test for precise identification of L. monocytogenes. We used bioinformatic tools to locate a specific conserved region of ActA for designing and developing an antibody-antigen based diagnostic test for the detection of L. monocytogenes. A number of databases were looked for ActA related sequences. Sequences were analyzed with several online software to find an appropriate region for our purpose. ActA protein was found specific to Listeria species with no homologs in other organisms. We finally introduced a highly conserved region within ActA sequence that possess several antibody binding sites specific to L. monocytogenes. This protein sequence can serve as an antigen for designing a relatively cheap, sensitive, and specific diagnostic test for detection of L. monocytogenes. PMID:22575546
Jahangiri, Abolfazl; Rasooli, Iraj; Reza Rahbar, Mohammad; Khalili, Saeed; Amani, Jafar; Ahmadi Zanoos, Kobra
An approach to segment lung pleura from CT data with high precision
NASA Astrophysics Data System (ADS)
A new approach to segment pleurae from CT data with high precision is introduced. This approach is developed in the segmentation's framework of an image analysis system to automatically detect pleural thickenings. The new technique to carry out the 3D segmentation of lung pleura is based on supervised range-constrained thresholding and a Gibbs-Markov random field model. An initial segmentation is done using the 3D histogram by supervised range-constrained thresholding. 3D connected component labelling is then applied to find the thorax. In order to detect and remove trachea and bronchi therein, the 3D histogram of connected pulmonary organs is modelled as a finite mixture of Gaussian distributions. Parameters are estimated using the Expectation-Maximization algorithm, which leads to the classification of that pulmonary region. As consequence left and right lungs are separated. Finally we apply a Gibbs-Markov random field model to our initial segmentation in order to achieve a high accuracy segmentation of lung pleura. The Gibbs- Markov random field is combined with maximum a posteriori estimation to estimate optimal pleural contours. With these procedures, a new segmentation strategy is developed in order to improve the reliability and accuracy of the detection of pleural contours and to achieve a better assessment performance of pleural thickenings.
Angelats, E.; Chaisaowong, K.; Knepper, A.; Kraus, T.; Aach, T.
Pattern placement metrology using PROVE high precision optics combined with advanced correction algorithms
NASA Astrophysics Data System (ADS)
Photolithography is the key technology of the chip production in semiconductor industry. Increasing demands on wafer overlay requirements lead to increasing demands on registration accuracy of photomasks. The PROVETM photomask registration metrology tool has been developed by Carl Zeiss SMS to address the need for high imaging resolution in combination with excellent measurement performance. This paper reports the current status of PROVEÖ, highlighting its optical performance and correction algorithms. The tool is designed for 193 nm illumination and imaging optics, which enables at-wavelength metrology for current and future photomask manufacturing requirements. Registration and line width metrology is offered by the optical beam path using transmitted or reflected light. The opportunity of selecting optimized illuminations allows a smart adaption of the tool to the measurement task. The short wavelength together with a numerical aperture of 0.6 allows sufficient resolution down to the 32 nm manufacturing technology requirements. The stable hardware platform and the newly developed PROVEÖ high precision optics enable a short term repeatability of less than 0.5 nm (3sigma). Distortion can be calibrated by using advanced image analysis and self calibration methods. The optical correction of the entire field of view delivers the requested screen linearity of less than 1 nm. It is shown, that the calculated optics correction is valid for different structure types and all kind of illuminations.
Lõngle, Mario; Rosenkranz, Norbert; Seidel, Dirk; Beyer, Dirk
The high throughput biomedicine unit at the institute for molecular medicine Finland: high throughput screening meets precision medicine.
The High Throughput Biomedicine (HTB) unit at the Institute for Molecular Medicine Finland FIMM was established in 2010 to serve as a national and international academic screening unit providing access to state of the art instrumentation for chemical and RNAi-based high throughput screening. The initial focus of the unit was multiwell plate based chemical screening and high content microarray-based siRNA screening. However, over the first four years of operation, the unit has moved to a more flexible service platform where both chemical and siRNA screening is performed at different scales primarily in multiwell plate-based assays with a wide range of readout possibilities with a focus on ultraminiaturization to allow for affordable screening for the academic users. In addition to high throughput screening, the equipment of the unit is also used to support miniaturized, multiplexed and high throughput applications for other types of research such as genomics, sequencing and biobanking operations. Importantly, with the translational research goals at FIMM, an increasing part of the operations at the HTB unit is being focused on high throughput systems biological platforms for functional profiling of patient cells in personalized and precision medicine projects. PMID:24661208
Pietiainen, Vilja; Saarela, Jani; von Schantz, Carina; Turunen, Laura; Ostling, Paivi; Wennerberg, Krister
Experimental high numerical aperture focusing with high contrast gratings.
We demonstrate high aperture (up to NA~0.64) three-dimensional focusing in free space based on wavefront-engineered diffraction gratings. The grating lens' optical response is tailored by spatially varying the grating ridge and groove width in two dimensions to achieve focal lengths of order 100 ?m that are crucial for micro-optical applications. The phase profile of the lens includes multiple 2? phase jumps and was obtained by applying an algorithm for finding the optimal path for both phase and amplitude. Experimental measurements reveal a lateral spot size of 5 ?m that is close to the size of a corresponding Airy disk. PMID:23988971
Klemm, Annett B; Stellinga, Daan; Martins, Emiliano R; Lewis, Liam; Huyet, Guillaume; O'Faolain, Liam; Krauss, Thomas F
Simulation of high precision pulsed laser fuze based on phase shifting
NASA Astrophysics Data System (ADS)
With the development of semiconductor laser technology, laser proximity fuzes have been widely used in various kinds of guided missiles and routine ammunitions. And its precision of ranging has a direct influence on the overall performance of the system. This work employed Spartan III series FPGA chip from Xilinx company. Through phase shifting the primary reference clock and ranging with four doubled-frequency clocks with each phase shiftings of 90 degree, the ranging precision can be improved obviously. The theoretical ranging error is 0.1875m and the result has been proven by simulation with Modelsim. Valuable conclusions were drawn for improving the ranging precision of laser fuze.
Chen, Huimin; Li, Ping; Peng, Zhoufeng; Wang, Xiaobo; Zhang, Yingwen
High precision predictions for near-Earth asteroids: the strange case of (3908) Nyx
NASA Astrophysics Data System (ADS)
In November 2004 near-Earth asteroid (3908) Nyx was successfully observed from the Arecibo radio telescope. However, the radar measurements turned out to be 7.5 sigma away from the orbital prediction. We prove that this anomaly was caused by a poor astrometric treatment and an inaccurate dynamical model. To improve the astrometric treatment, we applied the Chesley et al. (2010) debiasing and weighting scheme, and used an aggressive outlier rejection scheme. The main issue related to the dynamical model is due to the unaccounted Yarkovsky effect. Though the dataset available in 2004 allowed at best a marginal detection of the Yarkovsky signal, including the Yarkovsky effect in the model closes the gap between the orbital prediction and the radar measurements by both improving the nominal prediction and increasing the prediction uncertainty to a more realistic level. This analysis is an important lesson that shows the sensitivity of high precision predictions to the astrometric treatment and the Yarkovsky effect. By using the full observational dataset we obtain a 5 sigma detection of the Yarkovsky effect acting on Nyx from which we derive constraints on thermal inertia and bulk density. In particular, we obtain that the bulk density of Nyx is close to 1 g/cm^3. To make sure that our results are not corrupted by an asteroid impact or a close approach with a perturbing asteroid not included in our dynamical model, we rule out the possibility that Nyx experienced an instantaneous velocity variation while crossing the Main Belt region.
Farnocchia, Davide; Chesley, S. R.; Tholen, D. J.; Micheli, M.
A portable laser system for high-precision atom interferometry experiments
NASA Astrophysics Data System (ADS)
We present a modular rack-mounted laser system for the cooling and manipulation of neutral rubidium atoms which has been developed for a portable gravimeter based on atom interferometry that will be capable of performing high-precision gravity measurements directly at sites of geophysical interest. This laser system is constructed in a compact and mobile design so that it can be transported to different locations, yet it still offers improvements over many conventional laboratory-based laser systems. Our system is contained in a standard 19? rack and emits light at five different frequencies simultaneously on up to 12 fibre ports at a total output power of 800 mW. These frequencies can be changed and switched between ports in less than a microsecond. The setup includes two phase-locked diode lasers with a phase noise spectral density of less than 1 ?rad/Hz1/2 in the frequency range in which our gravimeter is most sensitive to noise. We characterise this laser system and evaluate the performance limits it imposes on an interferometer.
Schmidt, M.; Prevedelli, M.; Giorgini, A.; Tino, G. M.; Peters, A.
High-Precision Photometry of the Gamma-Ray Burst GRB 020813: The Smoothest Afterglow Yet
NASA Astrophysics Data System (ADS)
We report results of our precise reduction of the high signal-to-noise ratio VRI observations of the optical afterglow of the gamma-ray burst GRB 020813 obtained by Gladders & Hall with the Magellan 6.5 m telescope 3.9-4.9 hr after the burst. These observations are very well fitted locally by a power-law curve, providing the tightest constraints yet on how smooth the afterglows can be in some cases: the rms deviations range from 0.005 mag (0.5%) for the R band to 0.007 mag for the I band, only marginally larger than the rms scatter for nearby nonvariable stars. This scatter is a fac