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SciTech Connect
Gamma-ray bursts (GRBs) that emit photons at GeV energies form a small but significant population of GRBs. However, the number of GRBs whose GeV-emitting period is simultaneously observed in X-rays remains small. We report {gamma}-ray observations of GRB 110625A using Fermi's Large Area Telescope in the energy range 100 MeV-20 GeV. Gamma-ray emission at these energies was clearly detected using data taken between 180 s and 580 s after the burst, an epoch after the prompt emission phase. The GeV light curve differs from a simple power-law decay, and probably consists of two emission periods. Simultaneous Swift X-Ray Telescope observations did not show flaring behaviors as in the case of GRB 100728A. We discuss the possibility that the GeV emission is the synchrotron self-Compton radiation of underlying ultraviolet flares.
Tam, P. H. T.; Kong, A. K. H. [Institute of Astronomy and Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Fan Yizhong, E-mail: firstname.lastname@example.com [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)
Fermi Large Area Telescope Operations: Progress Over 4 Years
The Fermi Gamma-ray Space Telescope was launched into orbit in June 2008, and is conducting a multi-year gamma-ray all-sky survey, using the main instrument on Fermi, the Large Area Telescope (LAT). Fermi began its science mission in August 2008, and has now been operating for almost 4 years. The SLAC National Accelerator Laboratory hosts the LAT Instrument Science Operations Center (ISOC), which supports the operation of the LAT in conjunction with the Mission Operations Center (MOC) and the Fermi Science Support Center (FSSC), both at NASA's Goddard Space Flight Center. The LAT has a continuous output data rate of about 1.5 Mbits per second, and data from the LAT are stored on Fermi and transmitted to the ground through TDRS and the MOC to the ISOC about 10 times per day. Several hundred computers at SLAC are used to process LAT data to perform event reconstruction, and gamma-ray photon data are subsequently delivered to the FSSC for public release with a few hours of being detected by the LAT. We summarize the current status of the LAT, and the evolution of the data processing and monitoring performed by the ISOC during the first 4 years of the Fermi mission, together with future plans for further changes to detected event data processing and instrument operations and monitoring.
Cameron, Robert A.; /SLAC
Science Conference Proceedings (OSTI)
We present an analysis of gamma-ray data obtained with the Large Area Telescope on board the Fermi Gamma-ray Space Telescope in the region around supernova remnant (SNR) S147 (G180.0-1.7). A spatially extended gamma-ray source detected in an energy range of 0.2-10 GeV is found to coincide with SNR S147. We confirm its spatial extension at >5{sigma} confidence level. The gamma-ray flux is (3.8 {+-} 0.6) Multiplication-Sign 10{sup -8} photons cm{sup -2} s{sup -1}, corresponding to a luminosity of 1.3 Multiplication-Sign 10{sup 34} (d/1.3 kpc){sup 2} erg s{sup -1} in this energy range. The gamma-ray emission exhibits a possible spatial correlation with the prominent H{alpha} filaments of SNR S147. There is no indication that the gamma-ray emission comes from the associated pulsar PSR J0538+2817. The gamma-ray spectrum integrated over the remnant is likely dominated by the decay of neutral {pi} mesons produced through the proton-proton collisions in the filaments. The reacceleration of the pre-existing cosmic rays and subsequent adiabatic compression in the filaments is sufficient to provide the energy density required of high-energy protons.
Katsuta, J.; Uchiyama, Y.; Tanaka, T.; Tajima, H.; Bechtol, K.; Funk, S.; Lande, J. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France); Hanabata, Y. [Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Lemoine-Goumard, M. [Universite Bordeaux 1, CNRS/IN2p3, Centre d'Etudes Nucleaires de Bordeaux Gradignan, 33175 Gradignan (France); Takahashi, T., E-mail: firstname.lastname@example.com, E-mail: email@example.com [Institute of Space and Astronautical Science, Japanese Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)
Building ISOC Status Displays for the Large AreaTelescope aboard the Gamma Ray Large Area Space Telescope (GLAST) Observatory
DOE Green Energy (OSTI)
In September 2007 the Gamma Ray Large Area Space Telescope (GLAST) is scheduled to launch aboard a Delta II rocket in order to put two high-energy gamma-ray detectors, the Large Area Telescope (LAT) and the GLAST Burst Monitor (GBM) into low earth orbit. The Instrument Science Operations Center (ISOC) at SLAC is responsible for the LAT operations for the duration of the mission, and will therefore build an operations center including a monitoring station at SLAC to inform operations staff and visitors of the status of the LAT instrument and GLAST. This monitoring station is to include sky maps showing the location of GLAST in its orbit as well as the LAT's projected field of view on the sky containing known gamma-ray sources. The display also requires a world map showing the locations of GLAST and three Tracking and Data Relay Satellites (TDRS) relative to the ground, their trail lines, and ''footprint'' circles indicating the range of communications for each satellite. The final display will also include a space view showing the orbiting and pointing information of GLAST and the TDRS satellites. In order to build the displays the astronomy programs Xephem, DS9, SatTrack, and STK were employed to model the position of GLAST and pointing information of the LAT instrument, and the programming utilities Python and Cron were used in Unix to obtain updated information from database and load them into the programs at regular intervals. Through these methods the indicated displays were created and combined to produce a monitoring display for the LAT and GLAST.
Ketchum, Christina; /SLAC
The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission
The Large Area Telescope (Fermi/LAT, hereafter LAT), the primary instrument on the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view (FoV), high-energy {gamma}-ray telescope, covering the energy range from below 20 MeV to more than 300 GeV. The LAT was built by an international collaboration with contributions from space agencies, high-energy particle physics institutes, and universities in France, Italy, Japan, Sweden, and the United States. This paper describes the LAT, its preflight expected performance, and summarizes the key science objectives that will be addressed. On-orbit performance will be presented in detail in a subsequent paper. The LAT is a pair-conversion telescope with a precision tracker and calorimeter, each consisting of a 4 x 4 array of 16 modules, a segmented anticoincidence detector that covers the tracker array, and a programmable trigger and data acquisition system. Each tracker module has a vertical stack of 18 (x, y) tracking planes, including two layers (x and y) of single-sided silicon strip detectors and high-Z converter material (tungsten) per tray. Every calorimeter module has 96 CsI(Tl) crystals, arranged in an eight-layer hodoscopic configuration with a total depth of 8.6 radiation lengths, giving both longitudinal and transverse information about the energy deposition pattern. The calorimeter's depth and segmentation enable the high-energy reach of the LAT and contribute significantly to background rejection. The aspect ratio of the tracker (height/width) is 0.4, allowing a large FoV (2.4 sr) and ensuring that most pair-conversion showers initiated in the tracker will pass into the calorimeter for energy measurement. Data obtained with the LAT are intended to (1) permit rapid notification of high-energy {gamma}-ray bursts and transients and facilitate monitoring of variable sources, (2) yield an extensive catalog of several thousand high-energy sources obtained from an all-sky survey, (3) measure spectra from 20 MeV to more than 50 GeV for several hundred sources, (4) localize point sources to 0.3-2 arcmin, (5) map and obtain spectra of extended sources such as SNRs, molecular clouds, and nearby galaxies, (6) measure the diffuse isotropic {gamma}-ray background up to TeV energies, and (7) explore the discovery space for dark matter.
Atwood, W.B.; /UC, Santa Cruz; Abdo, Aous A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Anderson, B. /UC, Santa Cruz; Axelsson, M.; /Stockholm U.; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Band, D.L.; /NASA, Goddard /NASA, Goddard; Barbiellini, Guido; /INFN, Trieste /Trieste U.; Bartelt, J.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bastieri, Denis; /INFN, Padua /Padua U.; Baughman, B.M.; /Ohio State U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bederede, D.; /DAPNIA, Saclay; Bellardi, F.; /INFN, Pisa; Bellazzini, R.; /INFN, Pisa; Berenji, B.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bignami, G.F.; /Pavia U.; Bisello, D.; /INFN, Padua /Padua U.; Bissaldi, E.; /Garching, Max Planck Inst., MPE; Blandford, R.D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Perugia /Perugia U. /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Pisa /INFN, Pisa /Bari U. /INFN, Bari /Ecole Polytechnique /Washington U., Seattle /INFN, Padua /Padua U. /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /IASF, Milan /IASF, Milan /Kalmar U. /Royal Inst. Tech., Stockholm /DAPNIA, Saclay /ASI, Rome /INFN, Pisa /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /George Mason U. /Naval Research Lab, Wash., D.C. /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /DAPNIA, Saclay /NASA, Goddard /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Montpellier U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; /more authors..
Status of GLAST, the Gamma-ray Large-area Space Telescope
GLAST is a satellite-based observatory consisting of the Large-Area Telescope (LAT), a modular 4 x 4-tower pair-conversion telescope with a field-of-view greater than 2 steradians, capable of measuring gamma-ray energies in the range 20 MeV to 300 GeV, and the GLAST Burst Monitor (GBM), a set of NaI and BGO detectors covering 8 steradians and sensitive to photons with energies between 10 keV and 25 MeV, allowing for correlative observations of transient events. The observatory is currently being constructed and is scheduled to be launched in August 2007.
Rochester, L.; /SLAC
Fermi Large Area Telescope Observations of the Cosmic-Ray Induced
We report on measurements of the cosmic-ray induced {gamma}-ray emission of Earth's atmosphere by the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope. The LAT has observed the Earth during its commissioning phase and with a dedicated Earth-limb following observation in September 2008. These measurements yielded {approx} 6.4 x 10{sup 6} photons with energies > 100 MeV and {approx} 250 hours total livetime for the highest quality data selection. This allows the study of the spatial and spectral distributions of these photons with unprecedented detail. The spectrum of the emission - often referred to as Earth albedo gamma-ray emission - has a power-law shape up to 500 GeV with spectral index {Lambda} = 2.79 {+-} 0.06.
Abdo, A.
The On-Orbit Calibrations for the Fermi Large Area Telescope
The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope began its on-orbit operations on June 23, 2008. Calibrations, defined in a generic sense, correspond to synchronization of trigger signals, optimization of delays for latching data, determination of detector thresholds, gains and responses, evaluation of the perimeter of the South Atlantic Anomaly (SAA), measurements of live time, of absolute time, and internal and spacecraft boresight alignments. Here we describe on-orbit calibration results obtained using known astrophysical sources, galactic cosmic rays, and charge injection into the front-end electronics of each detector. Instrument response functions will be described in a separate publication. This paper demonstrates the stability of calibrations and describes minor changes observed since launch. These results have been used to calibrate the LAT datasets to be publicly released in August 2009.
Abdo, Aous A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ajello, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ampe, J.; /Naval Research Lab, Wash., D.C.; Anderson, B.; /UC, Santa Cruz; Atwood, W.B.; /UC, Santa Cruz; Axelsson, M.; /Stockholm U., OKC /Stockholm U.; Bagagli, R.; /INFN, Pisa; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Barbiellini, Guido; /INFN, Trieste /Trieste U.; Bartelt, J.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bastieri, Denis; /INFN, Padua /Padua U.; Baughman, B.M.; /Ohio State U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bederede, D.; /DAPNIA, Saclay; Bellardi, F.; /INFN, Pisa; Bellazzini, R.; /INFN, Pisa; Belli, F.; /Frascati /Rome U.,Tor Vergata; Berenji, B.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bisello, D.; /INFN, Padua /Padua U. /Garching, Max Planck Inst., MPE /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Ecole Polytechnique /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /DAPNIA, Saclay /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Pisa /INFN, Pisa /Bari U. /INFN, Bari /Ecole Polytechnique /Washington U., Seattle /INFN, Padua /Padua U. /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /IASF, Milan /IASF, Milan /Kalmar U. /Stockholm U., OKC /Royal Inst. Tech., Stockholm /DAPNIA, Saclay /ASDC, Frascati /INFN, Pisa /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /George Mason U. /Naval Research Lab, Wash., D.C. /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /DAPNIA, Saclay /NASA, Goddard /INFN, Perugia /Perugia U.; /more authors..
In-Flight Measurement of the Absolute Energy Scale of the Fermi Large Area Telescope
The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope is a pair-conversion telescope designed to survey the gamma-ray sky from 20 MeV to several hundreds of GeV. In this energy band there are no astronomical sources with sufficiently well known and sharp spectral features to allow an absolute calibration of the LAT energy scale. However, the geomagnetic cutoff in the cosmic ray electron-plus-positron (CRE) spectrum in low Earth orbit does provide such a spectral feature. The energy and spectral shape of this cutoff can be calculated with the aid of a numerical code tracing charged particles in the Earth's magnetic field. By comparing the cutoff value with that measured by the LAT in different geomagnetic positions, we have obtained several calibration points between {approx}6 and {approx}13 GeV with an estimated uncertainty of {approx}2%. An energy calibration with such high accuracy reduces the systematic uncertainty in LAT measurements of, for example, the spectral cutoff in the emission from gamma ray pulsars.
Ackermann, M.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Ajello, M.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Allafort, A.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Atwood, W.B.; /UC, Santa Cruz; Axelsson, M.; /Stockholm U. /Stockholm U., OKC /Royal Inst. Tech., Stockholm; Baldini, L.; /INFN, Pisa; Barbiellini, G.; /INFN, Trieste /Trieste U.; Bastieri, D.; /INFN, Padua /Padua U.; Bechtol, K.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Bellazzini, R.; /INFN, Pisa; Berenji, B.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Bloom, E.D.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, A.W.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Bouvier, A.; /UC, Santa Cruz; Bregeon, J.; /INFN, Pisa; Brez, A.; /INFN, Pisa; Brigida, M.; /Bari Polytechnic /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Buehler, R.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Buson, S.; /INFN, Padua /Padua U. /CSIC, Catalunya /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /IASF, Milan /DAPNIA, Saclay /INFN, Perugia /Perugia U. /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Unlisted, US /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /ASDC, Frascati /Perugia U. /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Montpellier U. /ASDC, Frascati /Bari Polytechnic /INFN, Bari /Naval Research Lab, Wash., D.C. /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Montpellier U. /Bari Polytechnic /INFN, Bari /Ecole Polytechnique /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Ecole Polytechnique /Hiroshima U. /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Bari Polytechnic /INFN, Bari /INFN, Bari /NASA, Goddard /INFN, Perugia /Perugia U.; /more authors..
Fermi Large Area Telescope Measurements of the Diffuse Gamma-Ray Emission at Intermediate Galactic Latitudes
The diffuse galactic {gamma}-ray emission is produced by cosmic rays (CRs) interacting with the interstellar gas and radiation field. Measurements by the Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on the Compton Gamma-Ray Observatory indicated excess {gamma}-ray emission {ge}1 GeV relative to diffuse galactic {gamma}-ray emission models consistent with directly measured CR spectra (the so-called 'EGRET GeV excess'). The Large Area Telescope (LAT) instrument on the Fermi Gamma-Ray Space Telescope has measured the diffuse {gamma}-ray emission with improved sensitivity and resolution compared to EGRET. We report on LAT measurements for energies 100 MeV to 10 GeV and galactic latitudes 10{sup o} {le} |b| {le} 20{sup o}. The LAT spectrum for this region of the sky is well reproduced by a diffuse galactic {gamma}-ray emission model that is consistent with local CR spectra and inconsistent with the EGRET GeV excess.
Abdo, A.A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; Ajello, M.; /SLAC; Anderson, B.; Atwood, W.B.; /UC, Santa Cruz; Axelsson, M.; /Stockholm U. /Stockholm U., OKC; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Barbiellini, G.; /INFN, Trieste /Trieste U.; Bastieri, D.; /INFN, Padua /Padua U.; Baughman, B.M.; /Taiwan, Natl. Taiwan U. /Ohio State U.; Bechtol, K.; /SLAC; Bellazzini, R.; /INFN, Pisa; Berenji, B.; Blandford, R.D.; Bloom, E.D.; /SLAC; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, A.W.; /SLAC; Bregeon, J.; Brez, A.; /INFN, Pisa; Brigida, M.; /Bari U. /INFN, Bari /Ecole Polytechnique /Washington U., Seattle /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /IASF, Milan /DAPNIA, Saclay /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Naval Research Lab, Wash., D.C. /George Mason U. /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Montpellier U. /Stockholm U. /Stockholm U., OKC /Royal Inst. Tech., Stockholm /Padua U. /Naval Research Lab, Wash., D.C. /Udine U. /INFN, Trieste /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /INFN, Pisa /UC, Santa Cruz /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /CENBG, Gradignan /CENBG, Gradignan /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Montpellier U. /Bari U. /INFN, Bari /Ecole Polytechnique /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Udine U. /INFN, Trieste /Hiroshima U. /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Bari U. /INFN, Bari /INFN, Pisa /INFN, Bari /NASA, Goddard /Maryland U.; /more authors..
The Trigger And Onboard Filter of the GLAST Large Area Telescope
The GLAST Large Area Telescope (LAT) will measure the cosmic gamma-ray flux in the energy range 20 MeV to >300 GeV. The LAT will open a new and important window on a wide variety of high-energy phenomena. Achieving this capability requires a hardware trigger and onboard software event filters that are robust and highly efficient for gamma rays while keeping the event rates due to the much larger fluxes of charged particle backgrounds at an acceptable level. Because of the important discovery windows for science and the uncertainties in the background fluxes, configuration flexibility is a particularly important system feature. This poster describes the purposes and architecture of the system, the components and capabilities of the hardware trigger and onboard software filters, testing and operation experience on the ground, and the on-orbit operations plan and expected performance.
Hughes, R.; /Ohio State U.; Grove, J.E.; /Naval Research Lab, Wash., D.C.; Kocian, M.; /SLAC; Ritz, S.; /Maryland U.; Russell, J.J.; /SLAC; Siskind, E.; /NYCB Real-Time Computing; Smith, P.; Winer, B.; /Ohio State U.; Usher, T.; /SLAC
Searches for cosmic-ray electron anisotropies with the Fermi Large Area Telescope
The Large Area Telescope on board the Fermi satellite (Fermi LAT) detected more than 1.6x10{sup 6} cosmic-ray electrons/positrons with energies above 60 GeV during its first year of operation. The arrival directions of these events were searched for anisotropies of angular scale extending from {approx}10 deg. up to 90 deg., and of minimum energy extending from 60 GeV up to 480 GeV. Two independent techniques were used to search for anisotropies, both resulting in null results. Upper limits on the degree of the anisotropy were set that depended on the analyzed energy range and on the anisotropy's angular scale. The upper limits for a dipole anisotropy ranged from {approx}0.5% to {approx}10%.
Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Bloom, E. D.; Borgland, A. W.; Bouvier, A.; Buehler, R.; Cameron, R. A.; Charles, E.; Chiang, J.; Claus, R.; Digel, S. W.; Couto e Silva, E. do; Drell, P. S.; Dubois, R.; Focke, W. B.; Funk, S.; Glanzman, T.; Godfrey, G. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94305 (United States)
Fermi Large Area Telescope Observations of the Cygnus Loop Supernova Remnant
We present an analysis of the gamma-ray measurements by the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope in the region of the supernova remnant (SNR) Cygnus Loop (G74.0-8.5). We detect significant gamma-ray emission associated with the SNR in the energy band 0.2-100 GeV. The gamma-ray spectrum shows a break in the range 2-3 GeV. The gamma-ray luminosity is {approx} 1 x 10{sup 33} erg s{sup -1} between 1-100 GeV, much lower than those of other GeV-emitting SNRs. The morphology is best represented by a ring shape, with inner/outer radii 0{sup o}.7 {+-} 0{sup o}.1 and 1{sup o}.6 {+-} 0{sup o}.1. Given the association among X-ray rims, H{alpha} filaments and gamma-ray emission, we argue that gamma rays originate in interactions between particles accelerated in the SNR and interstellar gas or radiation fields adjacent to the shock regions. The decay of neutral pions produced in nucleon-nucleon interactions between accelerated hadrons and interstellar gas provides a reasonable explanation for the gamma-ray spectrum.
Katagiri, H.; /Ibaraki U., Mito; Tibaldo, L.; /INFN, Padua /Padua U. /Paris U., VI-VII; Ballet, J.; /Paris U., VI-VII; Giordano, F.; /Bari U. /Bari Polytechnic /INFN, Bari; Grenier, I.A.; /Paris U., VI-VII; Porter, T.A.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Roth, M.; /Washington U., Seattle; Tibolla, O.; /Wurzburg U.; Uchiyama, Y.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Yamazaki, R.; /Sagamihara, Aoyama Gakuin U.
We quantitatively establish the sensitivity to the detection of young to middle-aged, isolated, gamma-ray pulsars through blind searches of Fermi Large Area Telescope (LAT) data using a Monte Carlo simulation. We detail a sensitivity study of the time-differencing blind search code used to discover gamma-ray pulsars in the first year of observations. We simulate 10,000 pulsars across a broad parameter space and distribute them across the sky. We replicate the analysis in the Fermi LAT First Source Catalog to localize the sources, and the blind search analysis to find the pulsars. We analyze the results and discuss the effect of positional error and spin frequency on gamma-ray pulsar detections. Finally, we construct a formula to determine the sensitivity of the blind search and present a sensitivity map assuming a standard set of pulsar parameters. The results of this study can be applied to population studies and are useful in characterizing unidentified LAT sources.
Dormody, M.; Johnson, R. P.; Atwood, W. B.; Belfiore, A.; Razzano, M.; Saz Parkinson, P. M. [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Grenier, I. A. [Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, F-91191 Gif sur Yvette (France); Johnson, T. J., E-mail: firstname.lastname@example.com [National Academy of Sciences, Washington, DC 20001 (United States)
Fermi Large Area Telescope Observations of the Supernova Remnant G8.7-0.1
We present a detailed analysis of the GeV gamma-ray emission toward the supernova remnant (SNR) G8.7-0.1 with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. An investigation of the relationship between G8.7-0.1 and the TeV unidentified source HESS J1804-216 provides us with an important clue on diffusion process of cosmic rays if particle acceleration operates in the SNR. The GeV gamma-ray emission is extended with most of the emission in positional coincidence with the SNR G8.7-0.1 and a lesser part located outside the western boundary of G8.7-0.1. The region of the gamma-ray emission overlaps spatially connected molecular clouds, implying a physical connection for the gamma-ray structure. The total gamma-ray spectrum measured with LAT from 200 MeV-100 GeV can be described by a broken power-law function with a break of 2.4 {+-} 0.6 (stat) {+-} 1.2 (sys) GeV, and photon indices of 2.10 {+-} 0.06 (stat) {+-} 0.10 (sys) below the break and 2.70 {+-} 0.12 (stat) {+-} 0.14 (sys) above the break. Given the spatial association among the gamma rays, the radio emission of G8.7-0.1, and the molecular clouds, the decay of p0s produced by particles accelerated in the SNR and hitting the molecular clouds naturally explains the GeV gamma-ray spectrum. We also find that the GeV morphology is not well represented by the TeV emission from HESS J1804-216 and that the spectrum in the GeV band is not consistent with the extrapolation of the TeV gamma-ray spectrum. The spectral index of the TeV emission is consistent with the particle spectral index predicted by a theory that assumes energy-dependent diffusion of particles accelerated in an SNR. We discuss the possibility that the TeV spectrum originates from the interaction of particles accelerated in G8.7-0.1 with molecular clouds, and we constrain the diffusion coefficient of the particles.
Ajello, M.; Allafort, A.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Baldini, L.; /INFN, Pisa; Ballet, J.; /AIM, Saclay; Barbiellini, G.; /INFN, Trieste /Trieste U.; Bastieri, D.; /INFN, Padua /Padua U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Bellazzini, R.; /INFN, Pisa; Berenji, B.; Blandford, R.D.; Bloom, E.D.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, A.W.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Bregeon, J.; /INFN, Pisa; Brigida, M.; /Bari Polytechnic /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Buehler, R.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Buson, S.; /INFN, Padua /Padua U.; Caliandro, G.A.; /CSIC, Catalunya; Cameron, R.A.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Caraveo, P.A.; /IASF, Milan /AIM, Saclay /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Unlisted, US /Naval Research Lab, Wash., D.C. /Perugia U. /ASDC, Frascati /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Montpellier U. /ASDC, Frascati /Udine U. /INFN, Trieste /Bari Polytechnic /INFN, Bari /Naval Research Lab, Wash., D.C. /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Bari Polytechnic /INFN, Bari /Ecole Polytechnique /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Udine U. /INFN, Trieste /Trieste Observ. /Hiroshima U. /Nagoya U. /Bari Polytechnic /INFN, Bari /INFN, Bari /ASDC, Frascati /INFN, Perugia /Perugia U. /Bari Polytechnic /INFN, Bari /ASDC, Frascati /Bari Polytechnic /INFN, Bari /Bologna Observ. /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Naval Research Lab, Wash., D.C. /Alabama U., Huntsville /CSIC, Catalunya /Hiroshima U. /NASA, Goddard /Hiroshima U.; /more authors..
Pulsed Gamma-Rays From PSR J2021 3651 with the Fermi Large Area Telescope
We report the detection of pulsed gamma-rays from the young, spin-powered radio pulsar PSR J2021+3651 using data acquired with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope (formerly GLAST). The light curve consists of two narrow peaks of similar amplitude separated by 0.468 {+-} 0.002 in phase. The first peak lags the maximum of the 2 GHz radio pulse by 0.162 {+-} 0.004 {+-} 0.01 in phase. The integral gamma-ray photon flux above 100 MeV is (56 {+-} 3 {+-} 11) x 10{sup -8} cm{sup -2} s{sup -1}. The photon spectrum is well-described by an exponentially cut-off power law of the form dF/dE = kE{sup -{Gamma}}e{sup (-E/E{sub c})} where the energy E is expressed in GeV. The photon index is {Gamma} = 1.5 {+-} 0.1 {+-} 0.1 and the exponential cut-off is E{sub c} = 2.4 {+-} 0.3 {+-} 0.5 GeV. The first uncertainty is statistical and the second is systematic. The integral photon flux of the bridge is approximately 10% of the pulsed emission, and the upper limit on off-pulse gamma-ray emission from a putative pulsar wind nebula is < 10% of the pulsed emission at the 95% confidence level. Radio polarization measurements yield a rotation measure of RM = 524 {+-} 4 rad m{sup -2} but a poorly constrained magnetic geometry. Re-analysis of Chandra data enhanced the significance of the weak X-ray pulsations, and the first peak is roughly phase-aligned with the first gamma-ray peak. We discuss the emission region and beaming geometry based on the shape and spectrum of the gamma-ray light curve combined with radio and X-ray measurements, and the implications for the pulsar distance. Gamma-ray emission from the polar cap region seems unlikely for this pulsar.
Abdo, Aous A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ajello, Marco; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Atwood, William B.; /UC, Santa Cruz; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Barbiellini, Guido; /INFN, Trieste /Trieste U.; Bastieri, Denis; /INFN, Padua /Padua U.; Battelino, Milan; /Royal Inst. Tech., Stockholm; Baughman, B.M.; /Ohio State U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bellazzini, Ronaldo; /INFN, Pisa; Berenji, Bijan; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bloom, Elliott D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bogaert, G.; /Ecole Polytechnique; Borgland, Anders W.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bregeon, J.; /INFN, Pisa; Brez, A.; /INFN, Pisa; Brigida, M.; /Bari U. /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Burnett, Thompson H.; /Washington U., Seattle /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Columbia U. /IASF, Milan /IASF, Milan /DAPNIA, Saclay /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /George Mason U. /Naval Research Lab, Wash., D.C. /IASF, Milan /IASF, Milan /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Perugia /Perugia U. /LPCE, Orleans /Montpellier U. /Sonoma State U. /Royal Inst. Tech., Stockholm /Stockholm U. /ASI, Rome /NRAO, Charlottesville /Naval Research Lab, Wash., D.C. /INFN, Trieste /Pavia U. /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /UC, Santa Cruz /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /CENBG, Gradignan /CENBG, Gradignan /Manchester U. /Montpellier U. /Bari U. /INFN, Bari; /more authors..
GRB 090926A was detected by both the Gamma-ray Burst Monitor and Large Area Telescope (LAT) instruments on board the Fermi Gamma-ray Space Telescope. Swift follow-up observations began {approx}13 hr after the initial trigger. The optical afterglow was detected for nearly 23 days post trigger, placing it in the long-lived category. The afterglow is of particular interest due to its brightness at late times, as well as the presence of optical flares at T0+10{sup 5} s and later, which may indicate late-time central engine activity. The LAT has detected a total of 16 gamma-ray bursts; nine of these bursts, including GRB 090926A, also have been observed by Swift. Of the nine Swift-observed LAT bursts, six were detected by UVOT, with five of the bursts having bright, long-lived optical afterglows. In comparison, Swift has been operating for five years and has detected nearly 500 bursts, but has only seen {approx}30% of bursts with optical afterglows that live longer than 10{sup 5} s. We have calculated the predicted gamma-ray fluence, as would have been seen by the Burst Alert Telescope (BAT) on board Swift, of the LAT bursts to determine whether this high percentage of long-lived optical afterglows is unique, when compared to BAT-triggered bursts. We find that, with the exception of the short burst GRB 090510A, the predicted BAT fluences indicate that the LAT bursts are more energetic than 88% of all Swift bursts and also have brighter than average X-ray and optical afterglows.
Swenson, C. A.; Roming, P. W. A.; Vetere, L.; Kennea, J. A. [Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Maxham, A.; Zhang, B. B.; Zhang, B. [University of Nevada, Las Vegas, Box 454002, 4505 Maryland Parkway, Las Vegas, NV 89154 (United States); Schady, P. [Max-Planck-Institut fuer extraterrestrische Physik, Garching (Germany); Holland, S. T. [Universities Space Research Association, 10227 Wincopin Circle, Suite 500, Columbia, MD 21044 (United States); Kuin, N. P. M.; Oates, S. R.; De Pasquale, M. [The UCL Mullard Space Science Laboratory, Holmbury St Mary, Surrey, RH5 6NT (United Kingdom); Page, K. L., E-mail: email@example.com [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)
The Spectrum of the Isotropic Diffuse Gamma-Ray Emission Derived From First-Year Fermi Large Area Telescope Data
We report on the first Fermi Large Area Telescope (LAT) measurements of the so-called 'extra-galactic' diffuse {gamma}-ray emission (EGB). This component of the diffuse {gamma}-ray emission is generally considered to have an isotropic or nearly isotropic distribution on the sky with diverse contributions discussed in the literature. The derivation of the EGB is based on detailed modelling of the bright foreground diffuse Galactic {gamma}-ray emission (DGE), the detected LAT sources and the solar {gamma}-ray emission. We find the spectrum of the EGB is consistent with a power law with differential spectral index {gamma} = 2.41 {+-} 0.05 and intensity, I(> 100 MeV) = (1.03 {+-} 0.17) x 10{sup -5} cm{sup -2} s{sup -1} sr{sup -1}, where the error is systematics dominated. Our EGB spectrum is featureless, less intense, and softer than that derived from EGRET data.
Abdo, A. A.
Pulsed Gamma-Rays From the Millisecond Pulsar J0030+0451 with the Fermi Large Area Telescope
We report the discovery of gamma-ray pulsations from the nearby isolated millisecond pulsar PSR J0030+0451 with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope (formerly GLAST). This discovery makes PSR J0030+0451 the second millisecond pulsar to be detected in gamma-rays after PSR J0218+4232, observed by the EGRET instrument on the Compton Gamma Ray Observatory. The spin-down power {dot E} = 3.5 x 10{sup 33} ergs s{sup -1} is an order of magnitude lower than the empirical lower bound of previously known gamma-ray pulsars. The emission profile is characterized by two narrow peaks, respectively 0.07 {+-} 0.01 and 0.08 {+-} 0.02 wide, separated by 0.44 {+-} 0.02 in phase. The first gamma-ray peak falls 0.15 {+-} 0.01 after the main radio peak. The pulse shape is similar to that of the 'normal' gamma-ray pulsars. An exponentially cut-off power-law fit of the emission spectrum leads to an integral photon flux above 100 MeV of (6.76 {+-} 1.05 {+-} 1.35) x 10{sup -8} cm{sup -2} s{sup -1} with cut-off energy (1.7 {+-} 0.4 {+-} 0.5) GeV. Based on its parallax distance of (300 {+-} 90) pc, we obtain a gamma-ray efficiency L{sub {gamma}}/{dot E} {approx_equal} 15% for the conversion of spin-down energy rate into gamma-ray radiation, assuming isotropic emission.
Abdo, Aous A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Atwood, W.B.; /UC, Santa Cruz; Axelsson, M. /Stockholm U., OKC /Stockholm U.; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Barbiellini, Guido; /INFN, Trieste /Trieste U.; Bastieri, Denis; /INFN, Padua /Padua U.; Battelino, M.; /Stockholm U., OKC /Royal Inst. Tech., Stockholm; Baughman, B.M.; /Ohio State U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bellazzini, R.; /INFN, Pisa; Berenji, B.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bloom, Elliott D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, A.W.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bregeon, J.; /INFN, Pisa; Brez, A.; /INFN, Pisa; Brigida, M.; /Bari U. /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Burnett, Thompson H.; /Washington U., Seattle /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /IASF, Milan /IASF, Milan /DAPNIA, Saclay /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /George Mason U. /Naval Research Lab, Wash., D.C. /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /LPCE, Orleans /Montpellier U. /Sonoma State U. /Stockholm U., OKC /Royal Inst. Tech., Stockholm /Stockholm U. /ASDC, Frascati /Naval Research Lab, Wash., D.C. /INFN, Trieste /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /UC, Santa Cruz /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /CENBG, Gradignan /CENBG, Gradignan /Montpellier U. /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Trieste /Hiroshima U.; /more authors..
FERMI LARGE AREA TELESCOPE DETECTION OF BRIGHT {gamma}-RAY OUTBURSTS FROM THE PECULIAR QUASAR 4C +21.35
In this paper, we report on the two-year-long Fermi-Large Area Telescope observation of the peculiar blazar 4C +21.35 (PKS 1222+216). This source was in a quiescent state from the start of the science operations of the Fermi Gamma-ray Space Telescope in 2008 August until 2009 September, and then became more active, with gradually increasing flux and some moderately bright flares. In 2010 April and June, 4C +21.35 underwent a very strong GeV outburst composed of several major flares characterized by rise and decay timescales of the order of a day. During the outburst, the GeV spectra of 4C +21.35 displayed a broken power-law form with spectral breaks observed near 1-3 GeV photon energies. We demonstrate that, at least during the major flares, the jet in 4C +21.35 carried a total kinetic luminosity comparable to the total accretion power available to feed the outflow. We also discuss the origin of the break observed in the flaring spectra of 4C +21.35. We show that, in principle, a model involving annihilation of the GeV photons on the He II Lyman recombination continuum and line emission of 'broad-line region' clouds may account for such. However, we also discuss the additional constraint provided by the detection of 4C +21.35 at 0.07-0.4 TeV energies by the MAGIC telescope, which coincided with one of the GeV flares of the source. We argue that there are reasons to believe that the {approx}< TeV emission of 4C +21.35 (as well as the GeV emission of the source, if co-spatial) is not likely to be produced inside the broad-line region zone of highest ionization ({approx}10{sup 17} cm from the nucleus), but instead originates further away from the active center, namely, around the characteristic scale of the hot dusty torus surrounding the 4C +21.35 nucleus ({approx}10{sup 19} cm).
Tanaka, Y. T.; Stawarz, L.; Saito, S.; Ohno, M.; Takahashi, T. [Institute of Space and Astronautical Science, JAXA, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Thompson, D. J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); D'Ammando, F. [IASF Palermo, 90146 Palermo (Italy); Fegan, S. J. [Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS/IN2P3, Palaiseau (France); Lott, B.; Escande, L. [Universite Bordeaux 1, CNRS/IN2p3, Centre d'Etudes Nucleaires de Bordeaux Gradignan, 33175 Gradignan (France); Wood, D. L.; Finke, J. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Cheung, C. C. [National Research Council Research Associate, National Academy of Sciences, Washington, DC 20001 (United States); Buson, S. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Donato, D. [Center for Research and Exploration in Space Science and Technology (CRESST) and NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Chiang, J. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Giroletti, M. [INAF Istituto di Radioastronomia, 40129 Bologna (Italy); Schinzel, F. K. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, 53121 Bonn (Germany); Iafrate, G.; Longo, F., E-mail: email@example.com [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy)
Dark Matter Constraints from Observations of 25 Milky Way Satellite Galaxies with the Fermi Large Area Telescope
E-Print Network (OSTI)
The dwarf spheroidal satellite galaxies of the Milky Way are some of the most dark-matter-dominated objects known. Due to their proximity, high dark matter content, and lack of astrophysical backgrounds, dwarf spheroidal galaxies are widely considered to be among the most promising targets for the indirect detection of dark matter via gamma rays. Here we report on gamma-ray observations of 25 Milky Way dwarf spheroidal satellite galaxies based on 4 years of Fermi Large Area Telescope (LAT) data. None of the dwarf galaxies are significantly detected in gamma rays, and we present gamma-ray flux upper limits between 500 MeV and 500 GeV. We determine the dark matter content of 18 dwarf spheroidal galaxies from stellar kinematic data and combine LAT observations of 15 dwarf galaxies to constrain the dark matter annihilation cross section. We set some of the tightest constraints to date on the the annihilation of dark matter particles with masses between 2 GeV and 10 TeV into prototypical Standard Model channels. We find these results to be robust against systematic uncertainties in the LAT instrument performance, diffuse gamma-ray background modeling, and assumed dark matter density profile.
The Fermi-LAT Collaboration; :; M. Ackermann; A. Albert; B. Anderson; L. Baldini; J. Ballet; G. Barbiellini; D. Bastieri; K. Bechtol; R. Bellazzini; E. Bissaldi; E. D. Bloom; E. Bonamente; A. Bouvier; T. J. Brandt; J. Bregeon; M. Brigida; P. Bruel; R. Buehler; S. Buson; G. A. Caliandro; R. A. Cameron; M. Caragiulo; P. A. Caraveo; C. Cecchi; E. Charles; A. Chekhtman; J. Chiang; S. Ciprini; R. Claus; J. Cohen-Tanugi; J. Conrad; F. D'Ammando; A. de Angelis; C. D. Dermer; S. W. Digel; E. do Couto e Silva; P. S. Drell; A. Drlica-Wagner; R. Essig; C. Favuzzi; E. C. Ferrara; A. Franckowiak; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; D. Gasparrini; N. Giglietto; M. Giroletti; G. Godfrey; G. A. Gomez-Vargas; I. A. Grenier; Guiriec; M. Gustafsson; M. Hayashida; E. Hays; J. Hewitt; R. E. Hughes; T. Jogler; T. Kamae; J. Knödlseder; D. Kocevski; M. Kuss; . Larsson; L. Latronico; M. Llena Garde; F. Longo; F. Loparco; M. N. Lovellette; P. Lubrano; G. Martinez; M. Mayer; M. N. Mazziotta; P. F. Michelson; W. Mitthumsiri; T. Mizuno; A. A. Moiseev; M. E. Monzani; A. Morselli; I. V. Moskalenko; S. Murgia; R. Nemmen; E. Nuss; T. Ohsugi; E. Orlando; J. F. Ormes; J. S. Perkins; F. Piron; G. Pivato; T. A. Porter; S. Rainň; R. Rando; M. Razzano; S. Razzaque; A. Reimer; O. Reimer; S. Ritz; M. Sŕnchez-Conde; N. Sehgal; C. Sgrň; E. J. Siskind; P. Spinelli; L. Strigari; D. J. Suson; H. Tajima; H. Takahashi; J. B. Thayer; L. Tibaldo; M. Tinivella; D. F. Torres; Y. Uchiyama; T. L. Usher; J. Vandenbroucke; G. Vianello; V. Vitale; M. Werner; B. L. Winer; K. S. Wood; M. Wood; G. Zaharijas; S. Zimmer
Constraining Dark Matter Models from a Combined Analysis of Milky Way Satellites with the Fermi Large Area Telescope
Satellite galaxies of the Milky Way are among the most promising targets for dark matter searches in gamma rays. We present a search for dark matter consisting of weakly interacting massive particles, applying a joint likelihood analysis to 10 satellite galaxies with 24 months of data of the Fermi Large Area Telescope. No dark matter signal is detected. Including the uncertainty in the dark matter distribution, robust upper limits are placed on dark matter annihilation cross sections. The 95% confidence level upper limits range from about 10{sup -26} cm{sup 3} s{sup -1} at 5 GeV to about 5 x 10{sup -23} cm{sup 3} s{sup -1} at 1 TeV, depending on the dark matter annihilation final state. For the first time, using gamma rays, we are able to rule out models with the most generic cross section ({approx}3 x 10{sup -26} cm{sup 3} s{sup -1} for a purely s-wave cross section), without assuming additional boost factors.
Ackermann, M.; Ajello, M.; /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC; Albert, A.; /Taiwan, Natl. Taiwan U. /Ohio State U.; Atwood, W.B.; /UC, Santa Cruz; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Barbiellini, G.; /INFN, Trieste /Trieste U.; Bastieri, D.; /INFN, Padua /Padua U.; Bechtol, K.; /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC; Bellazzini, R.; /INFN, Pisa; Berenji, B.; Blandford, R.D.; Bloom, E.D.; /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, A.W.; /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC; Bregeon, J.; /INFN, Pisa; Brigida, M.; /Bari Polytechnic /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Buehler, R.; /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC; Burnett, T.H.; /Washington U., Seattle; Buson, S.; /INFN, Padua /Padua U. /ICE, Bellaterra /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC /INFN, Rome /Rome U. /IASF, Milan /IASF, Milan /DAPNIA, Saclay /INFN, Perugia /Perugia U. /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC /Artep Inc. /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC /ASDC, Frascati /Perugia U. /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC /Montpellier U. /Stockholm U. /Stockholm U., OKC /ASDC, Frascati /ASDC, Frascati /Udine U. /INFN, Trieste /Bari Polytechnic /INFN, Bari /Naval Research Lab, Wash., D.C. /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC /Montpellier U. /Bari Polytechnic /INFN, Bari /Ecole Polytechnique /NASA, Goddard /Hiroshima U. /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC /Bari Polytechnic /INFN, Bari /INFN, Bari /ASDC, Frascati /NASA, Goddard /INFN, Perugia /Perugia U. /Bari Polytechnic /INFN, Bari /Bologna Observ. /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC /DAPNIA, Saclay /Alabama U., Huntsville; /more authors..
The Large Synoptic Survey Telescope
NLE Websites -- All DOE Office Websites (Extended Search)
night sky. Below: The telescope depicted at its future site atop Cerro Pachn in Chile. (Top image by Todd Mason, Mason Productions Inc. LSST Corporation. Bottom image...
BNL | Large Synoptic Survey Telescope (LSST)
Large Synoptic Survey Telescope Large Synoptic Survey Telescope About LSST Digital Sensor Array Brookhaven & Physics of the Universe LSST Project Website LSST: Providing an Unprecedented View of the Cosmos rendering of the LSST site in Chile A revolutionary 3.2 gigapixel camera mounted in a massive ground-based telescope will produce unprecedented views of the cosmos, driving discoveries with the widest, densest, and most complete images of our universe ever captured. New Visions The Large Synoptic Survey Telescope (LSST) will peer into space as no other telescope can. This new facility will create an unparalleled wide-field astronomical survey of our universe - wider and deeper in volume than all previous telescopes combined. The combination of a 3200 megapixel camera sensor array, a powerful supercomputer, a cutting-edge data processing and
Measurement of the Cosmic Ray e+ plus e- Spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope
Designed as a high-sensitivity gamma-ray observatory, the Fermi Large Area Telescope is also an electron detector with a large acceptance exceeding 2 m{sup 2}sr at 300 GeV. Building on the gamma-ray analysis, we have developed an efficient electron detection strategy which provides sufficient background rejection for measurement of the steeply-falling electron spectrum up to 1 TeV. Our high precision data show that the electron spectrum falls with energy as E{sup -3.0} and does not exhibit prominent spectral features. Interpretations in terms of a conventional diffusive model as well as a potential local extra component are briefly discussed.
Abdo, Aous A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ajello, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Atwood, W.B.; /UC, Santa Cruz; Axelsson, M.; /Stockholm U., OKC /Stockholm U.; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Barbiellini, Guido; /INFN, Trieste /Trieste U.; Bastieri, Denis; /INFN, Padua /Padua U.; Battelino, M.; /Stockholm U., OKC /Royal Inst. Tech., Stockholm; Baughman, B.M.; /Ohio State U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bellazzini, R.; /INFN, Pisa; Berenji, B.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Blandford, R.D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bloom, Elliott D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bogaert, G.; /Ecole Polytechnique; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, A.W.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bregeon, J.; /INFN, Pisa; Brez, A.; /INFN, Pisa /Bari U. /INFN, Bari /Ecole Polytechnique /Washington U., Seattle /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /IASF, Milan /IASF, Milan /Stockholm U., OKC /Royal Inst. Tech., Stockholm /DAPNIA, Saclay /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /George Mason U. /Naval Research Lab, Wash., D.C. /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Montpellier U. /Sonoma State U. /Stockholm U., OKC /Royal Inst. Tech., Stockholm /Stockholm U. /ASDC, Frascati /Naval Research Lab, Wash., D.C. /INFN, Trieste /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Pisa /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /CENBG, Gradignan /CENBG, Gradignan /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Montpellier U. /Bari U. /INFN, Bari; /more authors..
Very Large Aperture Diffractive Space Telescope
DOE Patents (OSTI)
A very large (10's of meters) aperture space telescope including two separate spacecraft--an optical primary functioning as a magnifying glass and an optical secondary functioning as an eyepiece. The spacecraft are spaced up to several kilometers apart with the eyepiece directly behind the magnifying glass ''aiming'' at an intended target with their relative orientation determining the optical axis of the telescope and hence the targets being observed. The magnifying glass includes a very large-aperture, very-thin-membrane, diffractive lens, e.g., a Fresnel lens, which intercepts incoming light over its full aperture and focuses it towards the eyepiece. The eyepiece has a much smaller, meter-scale aperture and is designed to move along the focal surface of the magnifying glass, gathering up the incoming light and converting it to high quality images. The positions of the two space craft are controlled both to maintain a good optical focus and to point at desired targets.
Hyde, Roderick Allen
Large area bulk superconductors
A bulk superconductor having a thickness of not less than about 100 microns is carried by a polycrystalline textured substrate having misorientation angles at the surface thereof not greater than about 15.degree.; the bulk superconductor may have a thickness of not less than about 100 microns and a surface area of not less than about 50 cm.sup.2. The textured substrate may have a thickness not less than about 10 microns and misorientation angles at the surface thereof not greater than about 15.degree.. Also disclosed is a process of manufacturing the bulk superconductor and the polycrystalline biaxially textured substrate material.
Miller, Dean J. (Darien, IL); Field, Michael B. (Jersey City, NJ)
Mid-Infrared Instrumentation for the European Extremely Large Telescope
MIDIR is the proposed thermal/mid-IR imager and spectrograph for the European Extremely Large Telescope (E-ELT). It will cover the wavelength range of 3 to at least 20 microns. Designed for diffraction-limited performance over the entire wavelength range, MIDIR will require an adaptive optics system; a cryogenically cooled system could offer optimal performance in the IR, and this is a critical aspect of the instrument design. We present here an overview of the project, including a discussion of MIDIR's science goals and a comparison with other infrared (IR) facilities planned in the next decade; top level requirements derived from these goals are outlined. We describe the optical and mechanical design work carried out in the context of a conceptual design study, and discuss some important issues to emerge from this work, related to the design, operation and calibration of the instrument. The impact of telescope optical design choices on the requirements for the MIDIR instrument is demonstrated.
S. Kendrew; B. Brandl; R. Lenzen; L. Venema; H. U. Käufl; G. Finger; A. Glasse; R. Stuik
Challenges in optics for Extremely Large Telescope instrumentation
We describe and summarize the optical challenges for future instrumentation for Extremely Large Telescopes (ELTs). Knowing the complex instrumental requirements is crucial for the successful design of 30-60m aperture telescopes. After all, the success of ELTs will heavily rely on its instrumentation and this, in turn, will depend on the ability to produce large and ultra-precise optical components like light-weight mirrors, aspheric lenses, segmented filters, and large gratings. New materials and manufacturing processes are currently under study, both at research institutes and in industry. In the present paper, we report on its progress with particular emphasize on volume-phase-holographic gratings, photochromic materials, sintered silicon-carbide mirrors, ion-beam figuring, ultra-precision surfaces, and free-form optics. All are promising technologies opening new degrees of freedom to optical designers. New optronic-mechanical systems will enable efficient use of the very large focal planes. We also provide exploratory descriptions of "old" and "new" optical technologies together with suggestions to instrument designers to overcome some of the challenges placed by ELT instrumentation.
P. Spanň; F. M. Zerbi; C. J. Norrie; C. R. Cunningham; K. G. Strassmeier; A. Bianco; P. A. Blanche; M. Bougoin; M. Ghigo; P. Hartmann; L. Zago; E. Atad-Ettedgui; B. Delabre; H. Dekker; M. Melozzi; B. Snyders; R. Takke; D. D. Walker
Large Synoptic Survey Telescope: From Science Drivers to Reference Design
In the history of astronomy, major advances in our understanding of the Universe have come from dramatic improvements in our ability to accurately measure astronomical quantities. Aided by rapid progress in information technology, current sky surveys are changing the way we view and study the Universe. Next-generation surveys will maintain this revolutionary progress. We focus here on the most ambitious survey currently planned in the visible band, the Large Synoptic Survey Telescope (LSST). LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: constraining dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. It will be a large, wide-field ground-based system designed to obtain multiple images covering the sky that is visible from Cerro Pachon in Northern Chile. The current baseline design, with an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg{sup 2} field of view, and a 3,200 Megapixel camera, will allow about 10,000 square degrees of sky to be covered using pairs of 15-second exposures in two photometric bands every three nights on average. The system is designed to yield high image quality, as well as superb astrometric and photometric accuracy. The survey area will include 30,000 deg{sup 2} with {delta} < +34.5{sup o}, and will be imaged multiple times in six bands, ugrizy, covering the wavelength range 320-1050 nm. About 90% of the observing time will be devoted to a deep-wide-fast survey mode which will observe a 20,000 deg{sup 2} region about 1000 times in the six bands during the anticipated 10 years of operation. These data will result in databases including 10 billion galaxies and a similar number of stars, and will serve the majority of science programs. The remaining 10% of the observing time will be allocated to special programs such as Very Deep and Very Fast time domain surveys. We describe how the LSST science drivers led to these choices of system parameters.
Ivezic, Z.; Axelrod, T.; Brandt, W.N.; Burke, D.L.; Claver, C.F.; Connolly, A.; Cook, K.H.; Gee, P.; Gilmore, D.K.; Jacoby, S.H.; Jones, R.L.; Kahn, S.M.; Kantor, J.P.; Krabbendam, V.; Lupton, R.H.; Monet, D.G.; Pinto, P.A.; Saha, A.; Schalk, T.L.; Schneider, D.P.; Strauss, Michael A.; /Washington U., Seattle, Astron. Dept. /LSST Corp. /Penn State U., Astron. Astrophys. /KIPAC, Menlo Park /NOAO, Tucson /LLNL, Livermore /UC, Davis /Princeton U., Astrophys. Sci. Dept. /Naval Observ., Flagstaff /Arizona U., Astron. Dept. - Steward Observ. /UC, Santa Cruz /Harvard U. /Johns Hopkins U. /Illinois U., Urbana
Building a better flat-field : an instrumental calibration projector for the Large Synoptic Survey Telescope
The Large Synoptic Survey Telescope (LSST) is a next-generation ground-based survey telescope whose science objectives demand photometric precision at the 1% level. Recent efforts towards 1% photometry have advocated in-situ ...
Vaz, Amali L
The Large Area Lyman Alpha Survey
The Lyman-$\\alpha$ line is expected to be strong in the presence of active star formation and the absence of dust, making it a good tool for finding chemically primitive galaxies in the early universe. We report on a new survey for high redshift Lyman-$\\alpha$ sources, the Large Area Lyman Alpha (LALA) survey. Our survey achieves an unprecedented combination of volume and sensitivity by using narrow-band filters on the new $8192^2$ pixel CCD Mosaic Camera at the 4 meter Mayall telescope of Kitt Peak National Observatory. Well-detected sources with flux and equivalent width matching known high redshift Lyman-$\\alpha$ galaxies have an observed surface density corresponding to $11000 \\pm 700$ per square degree per unit redshift at $z=4.5$. Early spectroscopic followup from the Keck telescope suggests that $\\sim 1/3$ of these are actually at $z\\approx 4.5$, and has confirmed five $z > 4$ Lyman-$\\alpha$ emitters so far. Combining our photometric survey with spectroscopic results, we estimate a net density of $\\sim...
Rhoads, J E; Dey, A; Jannuzi, B T; Stern, D; Spinrad, H; Rhoads, James E.; Malhotra, Sangeeta; Dey, Arjun; Jannuzi, Buell T.; Stern, Daniel
Large Synoptic Survey Telescope: Dark Energy Science Collaboration
This white paper describes the LSST Dark Energy Science Collaboration (DESC), whose goal is the study of dark energy and related topics in fundamental physics with data from the Large Synoptic Survey Telescope (LSST). It provides an overview of dark energy science and describes the current and anticipated state of the field. It makes the case for the DESC by laying out a robust analytical framework for dark energy science that has been defined by its members and the comprehensive three-year work plan they have developed for implementing that framework. The analysis working groups cover five key probes of dark energy: weak lensing, large scale structure, galaxy clusters, Type Ia supernovae, and strong lensing. The computing working groups span cosmological simulations, galaxy catalogs, photon simulations and a systematic software and computational framework for LSST dark energy data analysis. The technical working groups make the connection between dark energy science and the LSST system. The working groups have close linkages, especially through the use of the photon simulations to study the impact of instrument design and survey strategy on analysis methodology and cosmological parameter estimation. The white paper describes several high priority tasks identified by each of the 16 working groups. Over the next three years these tasks will help prepare for LSST analysis, make synergistic connections with ongoing cosmological surveys and provide the dark energy community with state of the art analysis tools. Members of the community are invited to join the LSST DESC, according to the membership policies described in the white paper. Applications to sign up for associate membership may be made by submitting the Web form at http://www.slac.stanford.edu/exp/lsst/desc/signup.html with a short statement of the work they wish to pursue that is relevant to the LSST DESC.
LSST Dark Energy Science Collaboration
The Lyman-$\\alpha$ line is expected to be strong in the presence of active star formation and the absence of dust, making it a good tool for finding chemically primitive galaxies in the early universe. We report on a new survey for high redshift Lyman-$\\alpha$ sources, the Large Area Lyman Alpha (LALA) survey. Our survey achieves an unprecedented combination of volume and sensitivity by using narrow-band filters on the new $8192^2$ pixel CCD Mosaic Camera at the 4 meter Mayall telescope of Kitt Peak National Observatory. Well-detected sources with flux and equivalent width matching known high redshift Lyman-$\\alpha$ galaxies have an observed surface density corresponding to $11000 \\pm 700$ per square degree per unit redshift at $z=4.5$. Early spectroscopic followup from the Keck telescope suggests that $\\sim 1/3$ of these are actually at $z\\approx 4.5$, and has confirmed five $z > 4$ Lyman-$\\alpha$ emitters so far. Combining our photometric survey with spectroscopic results, we estimate a net density of $\\sim 4000 $ Lyman-$\\alpha$ emitters per square degree per unit redshift at $z\\approx 4.5$. The star formation rate density (estimated both from UV continuum and from line emission) is comparable to that of the Lyman break galaxy population within present uncertainties. The most extreme Lyman-$\\alpha$ emitters in our sample have rest frame equivalent widths $> 100\\AA$, consistent with the expectations for the first burst of star formation in a primitive, dust-free galaxy.
James E. Rhoads; Sangeeta Malhotra; Arjun Dey; Buell T. Jannuzi; Daniel Stern; Hyron Spinrad
First Light Adaptive Optics System for Large Binocular Telescope S. Espositoa
First Light Adaptive Optics System for Large Binocular Telescope S. Espositoa , A. Tozzia , D of the single conjugate Adaptive Optics system to be installed on the LBT telescope. This system will be located optics is supposed to start from the beginning. The Adaptive Optics system to be used in first light
Fini, Luca
3D Technologies for Large Area Trackers
We describe technologies which can be developed to produce large area, low cost pixelated tracking detec- tors. These utilize wafer-scale 3D electronics and sensor technologies currently being developed in industry. This can result in fully active sensor/readout chip tiles which can be assembled into large area arrays with good yield and minimal dead area. The ability to connect though the bulk of the device can also provide better electrical performance and lower mass.
Deptuch, G; Johnson, M; Kenney, C; Lipton, R; Narian, M; Parker, S; Shenai, A; Spiegel, L; Thom, J; Ye, Z
G. Deptuch; U. Heintz; M. Johnson; C. Kenney; R. Lipton; M. Narian; S. Parker; A. Shenai; L. Spiegel; J. Thom; Z. Ye
Nanophosphors for Large Area Radiation Detectors
Homeland Security & Defense » Homeland Security & Defense » Nanophosphors for Large Area Radiation Detectors Nanophosphors for Large Area Radiation Detectors The present invention includes a composition comprising nanophosphor particles capped with a ligand. June 25, 2013 Nanophosphors for Large Area Radiation Detectors The present invention includes a composition comprising nanophosphor particles capped with a ligand. Available for thumbnail of Feynman Center (505) 665-9090 Email Nanophosphors for Large Area Radiation Detectors The present invention includes a composition comprising nanophosphor particles capped with a ligand. The nanophosphor particles have are less than or equal to 20 nanometers. The composition has at least one lanthanide and at least one halide. The weight percent of lanthanide
Early Cloud Formation by Large Area Fires
Fires simultaneously burning in hundreds of square kilometers could result from a nuclear weapon explosion. The strong buoyancy field of such large area fires induces high-velocity fire winds that turn upward in the burning region. This results ...
R. D. Small; K. E. Heikes
Multimedia Gallery from the Large Synoptic Survey Telescope (LSST) Project
DOE Data Explorer (OSTI)
The 8.4 meter Large LSST will survey the entire visible sky deeply in multiple colors every week with its three-billion pixel digital camera, probing the mysteries of Dark Matter and Dark Energy, and opening a movie-like window on objects that change or move rapidly: exploding supernovae, potentially hazardous near-Earth asteroids, and distant Kuiper Belt Objects. [Copied from http://www.lsst.org/lsst/about] The LSST is still in the design and development phase and will be ready for its scientific work approximately four years after construction starts in Chile. Meanwhile, the multimedia gallery on the LSST website provides insight into the project as it will look and operate. The images of the casting of the giant mirror are very interesting, as are the live webcam images of the leveling of land on top of El Pinon. Also available are animations and short video clips.
KM3NeT:a large underwater neutrino telescope in the Mediterranean Sea
High energy neutrinos produced in astrophysical processes will allow for a new way of studying the universe. In order to detect the expected flux of high energy neutrinos from specific astrophysical sources, neutrino telescopes of a scale of a km^3 of water will be needed. A Northern Hemisphere detector is being proposed to be sited in a deep area of the Mediterranean Sea. This detector will provide complimentary sky coverage to the IceCube detector being built at the South Pole. The three neutrino telescope projects in the Mediterranean (ANTARES, NEMO and NESTOR) are partners in an effort to design, and build such a km^3 size neutrino telescope, the KM3NeT. The EU is funding a 3-year Design Study; the status of the Design Study is presented and some technical issues are discussed.
P. A. Rapidis; for the KM3NeT consortium
Neutron Star Astronomy in the era of the European Extremely Large Telescope
About 25 isolated neutron stars (INSs) are now detected in the optical domain, mainly thanks to the HST and to VLT-class telescopes. The European Extremely Large Telescope(E-ELT) will yield {approx}100 new identifications, many of which from the follow-up of SKA, IXO, and Fermi observations. Moreover, the E-ELT will allow to carry out, on a much larger sample, INS observations which still challenge VLT-class telescopes, enabling studies on the structure and composition of the NS interior, of its atmosphere and magnetosphere, as well as to search for debris discs. In this contribution, I outline future perspectives for NS optical astronomy with the E-ELT.
Mignani, Roberto P. [Mullard Space Science Laboratory-University College London (United Kingdom)
First Results from the Large Area Lyman Alpha Survey
We report on a new survey for z=4.5 Lyman alpha sources, the Large Area Lyman Alpha (LALA) survey. Our survey achieves an unprecedented combination of volume and sensitivity by using narrow-band filters on the new 8192x8192 pixel CCD Mosaic Camera at the 4 meter Mayall telescope of Kitt Peak National Observatory. Well-detected sources with flux and equivalent width matching known high redshift Lyman alpha galaxies (i.e., observed equivalent width above 80 Angstroms and line+continuum flux between 2.6e-17 and 5.2e-17 erg/cm^2/sec in an 80 Angstrom filter) have an observed surface density corresponding to 11000 +- 700 per square degree per unit redshift at z=4.5. Spatial variation in this surface density is apparent on comparison between counts in 6561 and 6730 Angstrom filters. Early spectroscopic followup results from the Keck telescope included three sources meeting our criteria for good Lyman alpha candidates. Of these, one is confirmed as a z=4.52 source, while another remains consistent with either z=4.55 or z=0.81. We infer that 30 to 50% of our good candidates are bona fide Lyman alpha emitters, implying a net density of about 4000 Lyman alpha galaxies per square degree per unit redshift.
James E. Rhoads; Sangeeta Malhotra; Arjun Dey; Daniel Stern; Hyron Spinrad; Buell Jannuzi
First Results from the Large Area Lyman $\\alpha$ Survey
We report on a new survey for z=4.5 Lyman alpha sources, the Large Area Lyman Alpha (LALA) survey. Our survey achieves an unprecedented combination of volume and sensitivity by using narrow-band filters on the new 8192x8192 pixel CCD Mosaic Camera at the 4 meter Mayall telescope of Kitt Peak National Observatory. Well-detected sources with flux and equivalent width matching known high redshift Lyman alpha galaxies (i.e., observed equivalent width above 80 Angstroms and line+continuum flux between 2.6e-17 and 5.2e-17 erg/cm^2/sec in an 80 Angstrom filter) have an observed surface density corresponding to 11000 +- 700 per square degree per unit redshift at z=4.5. Spatial variation in this surface density is apparent on comparison between counts in 6561 and 6730 Angstrom filters. Early spectroscopic followup results from the Keck telescope included three sources meeting our criteria for good Lyman alpha candidates. Of these, one is confirmed as a z=4.52 source, while another remains consistent with either z=4.55...
Rhoads, J E; Dey, A; Stern, D; Spinrad, H; Jannuzi, B; Rhoads, James E.; Malhotra, Sangeeta; Dey, Arjun; Stern, Daniel; Spinrad, Hyron; Jannuzi, Buell
Influence of the Earth's magnetic field on large area photomultipliers
The influence of the Earth's magnetic field on large area photomultipliers proposed for a future deep sea neutrino telescope was studied under the EU-funded KM3NeT design study. The aims were to evaluate variations in PMT performance in the Earth's magnetic field and to decide whether the use of magnetic shielding is necessary. Measurements were performed on three Hamamatsu PMTs: two 8-inch R5912 types, one of these with super-bi-alkali photocathode, and a 10-inch R7081 type with a standard bi-alkali photocathode. The various characteristics of the PMTs were measured while varying the PMT orientations with respect to the Earth's magnetic field, both with and without a mu-metal cage as magnetic shield. In the 8-inch PMTs the impact of the magnetic field was found to be smaller than that on the 10-inch PMT. The increased quantum efficiency in the 8 super-bi-alkali PMT almost compensated its smaller detection surface compared to the 10' PMT. No significant effects were measured upon transit time and the fraction of spurious pulses. (authors)
Leonora, E.; Aiello, S. [INFN - National Inst. of Nuclear Physics, Section of Catania, CO Via Santa Sofia 64, 95123 Catania (Italy); Leotta, G. [Dept. of Physics and Astronomy of Catania, CO Via Santa Sofia 64, 95123 Catania (Italy)
Large Synoptic Survey Telescope (LSST) Posters from the 215th Meeting of the American Astronomical Society
The 8.4 meter Large LSST will survey the entire visible sky deeply in multiple colors every week with its three-billion pixel digital camera, probing the mysteries of Dark Matter and Dark Energy, and opening a movie-like window on objects that change or move rapidly: exploding supernovae, potentially hazardous near-Earth asteroids, and distant Kuiper Belt Objects. [Copied from http://www.lsst.org/lsst/about]
The LSST is still in the design and development phase and will be ready for its scientific work approximately four years after construction starts in Chile. The scientific posters prepared by members of the LSST Project Team for the 215 meeting of the American Astronomical Society in January of 2010 provide a detailed, technical look at the project components. Titles of posters available online include:
LSST Project Team Members
In this paper, we estimate the Large Synoptic Survey Telescope (LSST) yield of eclipsing binary stars, which will survey {approx}20,000 deg{sup 2} of the southern sky during a period of 10 years in six photometric passbands to r {approx} 24.5. We generate a set of 10,000 eclipsing binary light curves sampled to the LSST time cadence across the whole sky, with added noise as a function of apparent magnitude. This set is passed to the analysis-of-variance period finder to assess the recoverability rate for the periods, and the successfully phased light curves are passed to the artificial-intelligence-based pipeline ebai to assess the recoverability rate in terms of the eclipsing binaries' physical and geometric parameters. We find that, out of {approx}24 million eclipsing binaries observed by LSST with a signal-to-noise ratio >10 in mission lifetime, {approx}28% or 6.7 million can be fully characterized by the pipeline. Of those, {approx}25% or 1.7 million will be double-lined binaries, a true treasure trove for stellar astrophysics.
Prsa, Andrej [Department of Astronomy and Astrophysics, Villanova University, 800 East Lancaster Avenue, Villanova, PA 19085 (United States); Pepper, Joshua; Stassun, Keivan G., E-mail: firstname.lastname@example.com [Physics and Astronomy Department, Vanderbilt University, 2201 West End Avenue, Nashville, TN 37235 (United States)
Detection system based on a novel large area hybrid detector
A system level implementation of a large area hybrid detector is presented. The detector used in this system consists of an array of hydrogenated amorphous silicon photodiodes directly connected to a CMOS readout chip, which is vertically integrated ... Keywords: Amorphous silicon, Hybrid detectors, Large area photodetectors
A. Nascetti; P. Valerio; D. Caputo; G. de Cesare
High Energy Large Area Surveys: optically obscured AGN and the history of accretion
Hard X-ray, large area surveys are a fundamental complement of ultra-deep, pencil beam surveys in obtaining a more complete coverage of the L-z plane, allowing to find luminous QSO in wide z ranges. Furthermore, results from these surveys can be used to make reliable predictions about the luminosity (and hence the redshift) of the sources in the deep surveys which have optical counterparts too faint to be observed with the present generation of optical telescopes. This allows us to obtain accurate luminosity functions on wide luminosity and redshift intervals.
F. Fiore; the HELLAS2XMM collaboration
Argonne TDC: Large Area CCD X-Ray Detector
Large-Area CCD X-Ray Detector Opening Up New Horizons in the Study of Cellular and Metabolic Processes, Genetics, and Drug Development 2000 R&D 100 Award Winner!
The Robinson Gravitational Wave Background Telescope (BICEP): a bolometric large angular scale CMB polarimeter
The Robinson Telescope (BICEP) is a ground-based millimeter-wave bolometric array designed to study the polarization of the cosmic microwave background radiation (CMB) and galactic foreground emission. Such measurements probe the energy scale of the inflationary epoch, tighten constraints on cosmological parameters, and verify our current understanding of CMB physics. Robinson consists of a 250-mm aperture refractive telescope that provides an instantaneous field-of-view of 17 degrees with angular resolution of 55 and 37 arcminutes at 100 GHz and 150 GHz, respectively. Forty-nine pair of polarization-sensitive bolometers are cooled to 250 mK using a 4He/3He/3He sorption fridge system, and coupled to incoming radiation via corrugated feed horns. The all-refractive optics is cooled to 4 K to minimize polarization systematics and instrument loading. The fully steerable 3-axis mount is capable of continuous boresight rotation or azimuth scanning at speeds up to 5 deg/s. Robinson has begun its first season of observation at the South Pole. Given the measured performance of the instrument along with the excellent observing environment, Robinson will measure the E-mode polarization with high sensitivity, and probe for the B-modes to unprecedented depths. In this paper we discuss aspects of the instrument design and their scientific motivations, scanning and operational strategies, and the results of initial testing and observations.
K. W. Yoon; P. A. R. Ade; D. Barkats; J. O. Battle; E. M. Bierman; J. J. Bock; J. A. Brevik; H. C. Chiang; A. Crites; C. D. Dowell; L. Duband; G. S. Griffin; E. F. Hivon; W. L. Holzapfel; V. V. Hristov; B. G. Keating; J. M. Kovac; C. L. Kuo; A. E. Lange; E. M. Leitch; P. V. Mason; H. T. Nguyen; N. Ponthieu; Y. D. Takahashi; T. Renbarger; L. C. Weintraub; D. Woolsey
Large-area metallic photonic lattices for military applications.
In this project we developed photonic crystal modeling capability and fabrication technology that is scaleable to large area. An intelligent optimization code was developed to find the optimal structure for the desired spectral response. In terms of fabrication, an exhaustive survey of fabrication techniques that would meet the large area requirement was reduced to Deep X-ray Lithography (DXRL) and nano-imprint. Using DXRL, we fabricated a gold logpile photonic crystal in the plane. For the nano-imprint technique, we fabricated a cubic array of gold squares. These two examples also represent two classes of metallic photonic crystal topologies, the connected network and cermet arrangement.
Luk, Ting Shan
In this project we developed photonic crystal modeling capability and fabrication technology that is scaleable to large area. An intelligent optimization code was developed to find the optimal structure for the desired spectral response. In terms of fabrication, an exhaustive survey of fabrication techniques that would meet the large area requirement was reduced to Deep X-ray Lithography (DXRL) and nano-imprint. Using DXRL, we fabricated a gold logpile photonic crystal in the <100> plane. For the nano-imprint technique, we fabricated a cubic array of gold squares. These two examples also represent two classes of metallic photonic crystal topologies, the connected network and cermet arrangement.
Semiconductor-based, large-area, flexible, electronic devices
Novel articles and methods to fabricate the same resulting in flexible, large-area, triaxially textured, single-crystal or single-crystal-like, semiconductor-based, electronic devices are disclosed. Potential applications of resulting articles are in areas of photovoltaic devices, flat-panel displays, thermophotovoltaic devices, ferroelectric devices, light emitting diode devices, computer hard disc drive devices, magnetoresistance based devices, photoluminescence based devices, non-volatile memory devices, dielectric devices, thermoelectric devices and quantum dot laser devices.
Goyal, Amit (Knoxville, TN)
Modeling a Dry Etch Process for Large-Area Devices
There has been considerable interest in developing dry processes which can effectively replace wet processing in the manufacture of large area photovoltaic devices. Environmental and health issues are a driver for this activity because wet processes generally increase worker exposure to toxic and hazardous chemicals and generate large volumes of liquid hazardous waste. Our work has been directed toward improving the performance of screen-printed solar cells while using plasma processing to reduce hazardous chemical usage.
Buss, R.J.; Hebner, G.A.; Ruby, D.S.; Yang, P.
Finding Large Aperture Fractures in Geothermal Resource Areas Using a
Open Energy Info (EERE)
Finding Large Aperture Fractures in Geothermal Resource Areas Using a Finding Large Aperture Fractures in Geothermal Resource Areas Using a Three-Component Long-Offset Surface Seismic Survey Geothermal Project Jump to: navigation, search Last modified on July 22, 2011. Project Title Finding Large Aperture Fractures in Geothermal Resource Areas Using a Three-Component Long-Offset Surface Seismic Survey Project Type / Topic 1 Recovery Act: Geothermal Technologies Program Project Type / Topic 2 Validation of Innovative Exploration Technologies Project Description Because fractures and faults with sub-commercial permeability can propagate hot fluid and hydrothermal alteration throughout a geothermal reservoir, potential field geophysical methods including resistivity, gravity, heatflow and magnetics cannot distinguish between low-permeability fractures and LAF's (Large Aperature Fractures). USG will develop and test the combination of three-component,long-offset seismic surveying, permanent scatter synthetic aperture radar interferometry (PSInSAR) and structural kinematic analysis as an integrated method for locating and 3-D mapping of LAF's in shallow to intermediate depth (600-4000 feet) geothermal systems. This project is designed to test the methodology on known occurrences of LAF's and then apply the technology to expand an existing production field and find a new production field in a separate but related resource area. A full diameter production well will be drilled into each of the two lease blocks covered by the geophysical exploration program.
The South Pole Telescope
A new 10 meter diameter telescope is being constructed for deployment at the NSF South Pole research station. The telescope is designed for conducting large-area millimeter and sub-millimeter wave surveys of faint, low contrast emission, as required to map primary and secondary anisotropies in the cosmic microwave background. To achieve the required sensitivity and resolution, the telescope design employs an off-axis primary with a 10m diameter clear aperture. The full aperture and the associated optics will have a combined surface accuracy of better than 20 microns rms to allow precision operation in the submillimeter atmospheric windows. The telescope will be surrounded with a large reflecting ground screen to reduce sensitivity to thermal emission from the ground and local interference. The optics of the telescope will support a square degree field of view at 2mm wavelength and will feed a new 1000-element micro-lithographed planar bolometric array with superconducting transition-edge sensors and frequency-multiplexed readouts. The first key project will be to conduct a survey over approximately 4000 degrees for galaxy clusters using the Sunyaev-Zel'dovich Effect. This survey should find many thousands of clusters with a mass selection criteria that is remarkably uniform with redshift. Armed with redshifts obtained from optical and infrared follow-up observations, it is expected that the survey will enable significant constraints to be placed on the equation of state of the dark energy.
SPT Collaboration; J. E. Ruhl; P. A. R. Ade; J. E. Carlstrom; H. M. Cho; T. Crawford; M. Dobbs; C. H. Greer; N. W. Halverson; W. L. Holzapfel; T. M. Lantin; A. T. Lee; J. Leong; E. M. Leitch; W. Lu; M. Lueker; J. Mehl; S. S. Meyer; J. J. Mohr; S. Padin; T. Plagge; C. Pryke; D. Schwan; M. K. Sharp; M. C. Runyan; H. Spieler; Z. Staniszewski; A. A. Stark
Characterization of Large Area APDs for the EXO-200 Detector
EXO-200 uses 468 large area avalanche photodiodes (LAAPDs) for detection of scintillation light in an ultra-low-background liquid xenon (LXe) detector. We describe initial measurements of dark noise, gain and response to xenon scintillation light of LAAPDs at temperatures from room temperature to 169 K - the temperature of liquid xenon. We also describe the individual characterization of more than 800 LAAPDs for selective installation in the EXO-200 detector.
Neilson, R.; LePort, F.; Pocar, A.; /Stanford U., Phys. Dept.; Kumar, K.; /Massachusetts U., Amherst; Odian, A.; Prescott, C.Y.; /SLAC; Tenev, V.; /Stanford U., Phys. Dept.; Ackerman, N.; /SLAC; Akimov, D.; /Moscow, ITEP; Auger, M.; /Bern U., LHEP; Benitez-Medina, C.; /Colorado State U.; Breidenbach, M.; /SLAC; Burenkov, A.; /Moscow, ITEP; Conley, R.; /SLAC; Cook, S.; /Colorado State U.; deVoe, R.; Dolinski, M.J.; /Stanford U., Phys. Dept.; Fairbank, W., Jr.; /Colorado State U.; Farine, J.; /Laurentian U.; Fierlinger, P.; Flatt, B.; /Stanford U., Phys. Dept. /Bern U., LHEP /Stanford U., Phys. Dept. /Maryland U. /Colorado State U. /Laurentian U. /Carleton U. /SLAC /Maryland U. /Moscow, ITEP /Alabama U. /SLAC /Colorado State U. /Stanford U., Phys. Dept. /Alabama U. /Stanford U., Phys. Dept. /Alabama U. /SLAC /Carleton U. /SLAC /Maryland U. /Moscow, ITEP /Carleton U. /Stanford U., Phys. Dept. /Bern U., LHEP /SLAC /Laurentian U. /SLAC /Maryland U.
An amplifier for use with large-area photodiodes
We describe a high-gain ({approximately}10{sup 7}) amplifier for use with large-area silicon photodiodes for monitoring the intensity of plasma light from fusion experiments. To achieve the necessary gain without saturating the output signal, the amplifier design incorporates a bootstrap technique and capacitive coupling between amplifier stages. This design eliminates voltage offset at the amplifier output due to detector leakage, while retaining desirable low-frequency response characteristics.
Dyer, G.R.; Uckan, T. (Fusion Energy Division, Oak Ridge National Laboratory, Oak Ridge, TN (USA))
High-Throughput Dry Processes for Large-Area Devices
In October 1996, an interdisciplinary team began a three-year LDRD project to study the plasma processes of reactive ion etching and plasma-enhanced chemical vapor deposition on large-area silicon devices. The goal was to develop numerical models that could be used in a variety of applications for surface cleaning, selective etching, and thin-film deposition. Silicon solar cells were chosen as the experimental vehicle for this project because an innovative device design was identified that would benefit from immediate performance improvement using a combination of plasma etching and deposition processes. This report presents a summary of the technical accomplishments and conclusions of the team.
Large-Area Zone Plate Fabrication with Optical Lithography
Zone plates as condenser optics for x-ray microscopes offer simple optical designs for both illumination and spectral resolution when used as a linear monochromator. However, due to the long write times for electron beam lithography, both the availability and the size of zone plates for condensers have been limited. Since the resolution provided by the linear monochromator scales almost linearly with the diameter of the zone plate, the full potential for zone plate monochromators as illumination systems for x-ray microscopes has not been achieved. For example, the 10-mm-diameter zone plate has demonstrated a spectral resolution of E/{Delta}E = 700[1], but with a 26-mm-diameter zone plate, the calculated spectral resolution is higher than E/{Delta}E = 3000. These large-area zone plates are possible to fabricate with the leading edge semiconductor lithography tools such as those available at the College of Nanoscale Science and Engineering at the University at Albany. One of the lithography tools available is the ASML TWINSCAN XT: 1950i with 37-nm resolution [2]. A single 300-mm wafer can contain more than 60 fields, each with a large area condenser, and the throughput of the tool can be more than one wafer every minute.
Denbeaux, G. [College of Nanoscale Science and Engineering, University at Albany, 255 Fuller Road, Albany, NY 12203 (United States)
Plasma generating apparatus for large area plasma processing
A plasma generating apparatus for plasma processing applications is based on a permanent magnet line-cusp plasma confinement chamber coupled to a compact single-coil microwave waveguide launcher. The device creates an electron cyclotron resonance (ECR) plasma in the launcher and a second ECR plasma is created in the line cusps due to a 0.0875 tesla magnetic field in that region. Additional special magnetic field configuring reduces the magnetic field at the substrate to below 0.001 tesla. The resulting plasma source is capable of producing large-area (20-cm diam), highly uniform (.+-.5%) ion beams with current densities above 5 mA/cm[sup 2]. The source has been used to etch photoresist on 5-inch diam silicon wafers with good uniformity. 3 figures.
Tsai, C.C.; Gorbatkin, S.M.; Berry, L.A.
A plasma generating apparatus for plasma processing applications is based on a permanent magnet line-cusp plasma confinement chamber coupled to a compact single-coil microwave waveguide launcher. The device creates an electron cyclotron resonance (ECR) plasma in the launcher and a second ECR plasma is created in the line cusps due to a 0.0875 tesla magnetic field in that region. Additional special magnetic field configuring reduces the magnetic field at the substrate to below 0.001 tesla. The resulting plasma source is capable of producing large-area (20-cm diam), highly uniform (.+-.5%) ion beams with current densities above 5 mA/cm.sup.2. The source has been used to etch photoresist on 5-inch diam silicon wafers with good uniformity.
Tsai, Chin-Chi (Oak Ridge, TN); Gorbatkin, Steven M. (Oak Ridge, TN); Berry, Lee A. (Oak Ridge, TN)
A large area detector for x-ray applications
A large area detector for x-ray synchrotron applications has been developed. The front end of this device consist of a scintillator coupled to a fiber-optic taper. The fiber-optic taper is comprised of 4 smaller (70 mm x 70 mm) tapers fused together in a square matrix giving an active area of 140 mm x 140 mm. Each taper has a demagnification of 5.5 resulting in four small ends that are 12 mm diagonally across. The small ends of each taper are coupled to four microchannel-plate-based image intensifiers. The output from each image intensifier is focused onto a Charge Coupled Device (CCD) detector. The four CCDs are read out in parallel and are independently controlled. The image intensifiers also act as fast (20 ns) electronic shutters. The system is capable of displaying images in real time. Additionally, with independent control on the readout of each row of data from the CCD, the system is capable of performing high speed imaging through novel readout manipulation.
Rodricks, B.; Huang, Qiang; Hopf, R.; Wang, Kemei
Prediction and correlation of accessible area of large multiparticle aggregates
Aggregates (composed of large numbers of primary particles) are produced in many engineering environments. One convenient characterization is the fractal dimension, the exponent describing how the number of primary particles in each aggregate scales with radial distance from its center of mass. The authors describe a finite-analytic pseudo-continuum prediction of the normalized accessible surface area of an isothermal quasi-spherical fractal aggregate containing N ([much gt]1) primary particles, on the surfaces of which a first-order chemical process occurs. Results are displayed for specific fractal dimensions (2.5, 2.18, and 1.8) frequently observed in aggregating systems. An effective Thiele modulus is used to develop an efficient and accurate scheme for predicting/correlating the effectiveness factor for an aggregate containing N primary particles in terms of aggregate fractal dimension, reaction probability, and Knudsen number. The methods now allow calculations of the accessible surface area of populations of aggregates, provided pdf--(N, D[sub f], ...)--is known for the populations of interest.
Rosner, D.E.; Tandon, P. (Yale Univ., New Haven, CT (United States). Dept. of Chemical Engineering)
Development of a New Laser Beacon for Time Calibration in the ANTARES Neutrino Telescope
The ANTARES collaboration has built a deep sea neutrino telescope in the Mediterranean Sea consisting of a matrix of pressure resistant glass spheres holding large area photomultipliers. The aim of the telescope is to observe cosmic neutrinos through ... Keywords: Deep Sea Instrumentation, Time Calibration Device, Neutrino Telescope, Laser Beacon.
Umberto Emanuele; Diego Real; Fernando Urbano; Juan de Dios Zornoza; Juan Zuniga
Fast Fourier transform telescope
We propose an all-digital telescope for 21 cm tomography, which combines key advantages of both single dishes and interferometers. The electric field is digitized by antennas on a rectangular grid, after which a series of fast Fourier transforms recovers simultaneous multifrequency images of up to half the sky. Thanks to Moore's law, the bandwidth up to which this is feasible has now reached about 1 GHz, and will likely continue doubling every couple of years. The main advantages over a single dish telescope are cost and orders of magnitude larger field-of-view, translating into dramatically better sensitivity for large-area surveys. The key advantages over traditional interferometers are cost (the correlator computational cost for an N-element array scales as Nlog{sub 2}N rather than N{sup 2}) and a compact synthesized beam. We argue that 21 cm tomography could be an ideal first application of a very large fast Fourier transform telescope, which would provide both massive sensitivity improvements per dollar and mitigate the off-beam point source foreground problem with its clean beam. Another potentially interesting application is cosmic microwave background polarization.
Tegmark, Max; Zaldarriaga, Matias [Department of Physics and MIT Kavli Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Center for Astrophysics, Harvard University, Cambridge, Massachusetts 02138 (United States)
Finding Large Aperture Fractures in Geothermal Resource Areas...
low-permeability fractures and LAF's (Large Aperature Fractures). USG will develop and test the combination of three-component,long-offset seismic surveying, permanent scatter...
Plan for support of large-plant (post-CRBR) needs in large-leak sodium-water reaction area
Work in the large leak test and analysis area of steam generator development has been carried out at GE-ARSD under 189a SG037 since 1973. The currently planned master schedule for the SG037 program is shown. Principal activities are the large leak testing program being carried out at the Large Leak Test Rig and the analysis methods development. The plan for supporting the large plant (post-CRBR) needs in the large leak sodium-water reaction area is outlined. Most of the needs will be answered in the current SG037 large leak program. (DLC)
Whipple, J.C.
Radiation Portal Monitoring Test Area and Large Detector
a transformation. In the summer of 2007, work began on the nearly 200,000-square-foot Physical Sciences Facility, equipment and staff displaced from accelerated cleanup of Hanford's 300 Area. This federally financed detection and testing · Borderandinterdiction technology · Materialsdevelopmentand engineering
Development of large-area Micro-channel Plate Photodetectors
: Imaging, gain mapping, and timing · Integrated electronics: DAQ system and fast waveform recording LAPPD = `tile'  Gain > 107 with two MCP plates  RF Transmission line anode  Internal HV distribution Large;10 May 2013 15 The 8" glass package LAPPD Collaboration MCPs Grid spacers Anode microstrips Top Window
Interactive large data exploration over the wide area
The top supercomputers typically have aggregate memories in excess of 100 TB, with simulations running on these systems producing datasets of comparable size. The size of these datasets and the speed with which they are produced define the minimum performance ... Keywords: large data, remote data exploration, visualization
Mark Hereld; Michael E. Papka; Joseph A. Insley; Michael L. Norman; Eric C. Olson; Rick Wagner
The detonation of shot one at Bikini Atoll on March 1, 1954, produced a fallout of radioactive ash upon Rongelap Atoll, Marshall Islands. The distribution of the radioactive ash on the islands and in the plants and animals of the area has been studied and evaluated. During the first expedition to Rongelap Atoll on March 26, 1954, biological samples were collected and measurements made of the radiation contamination. On three additional expeditions extensive collections of material were made for this study, the last on January 25-30, 1955. The decline in radioactivity was measured in 1499 samples of fish, invertebrates, land plants, algae, birds, plankton, soil, and water from the Rongelap area. During this study particular emphasis was placed upon evaluation of the radioactivity in food used by the natives. Coconut milk collected on March 26, 1954, contained 1.03 microcuries per kilogram of wet tissue while the coconut meat had 1.16 mu c/kg. By January 25-30, 1955, the level in coconut milk had declined to 0.041 mu c/kg and the meat to 0.036 mu c/ kg. Fish muscle on March 26, 1954, averaged 2.74 mu c/kg and fish liver 204.0 mu c/kg. The decline to January 25-30 was 0.10 mu c/kg for the muscle and 3.52 mu c/kg for the liver of fish. Somewhat similar declines were found for clam muscle, crab muscle, bird muscle and liver, and for squash, papaya, arrowroot and pandanus. The level of radioactivity was highest in the northern portion of the atoll, except for samples of algae and fish-eating birds, collected during January 1955 from the southern part of the atoll, which had higher levels of radioactivity than samples collected from the northern islands on the same date. This may indicate a translocation of radioactive materials within the lagoon. (auth)
Berkley, K.M.; Pearse, H.E.
Power Challenges of Large Scale Research Infrastructures: the Square Kilometer Array and Solar Energy Integration; Towards a zero-carbon footprint next generation telescope
The Square Kilometer Array (SKA) will be the largest Global science project of the next two decades. It will encompass a sensor network dedicated to radioastronomy, covering two continents. It will be constructed in remote areas of South Africa and Australia, spreading over 3000Km, in high solar irradiance latitudes. Solar Power supply is therefore an option to power supply the SKA and contribute to a zero carbon footprint next generation telescope. Here we outline the major characteristics of the SKA and some innovation approaches on thermal solar energy Integration with SKA prototypes.
Barbosa, Domingos; Ruiz, Valeriano; Silva, Manuel; Verdes-Montenegro, Lourdes; Santander-Vela, Juande; Maia, Dalmiro; Antón, Sonia; van Ardenne, Arnold; Vetter, Matthias; Kramer, Michael; Keller, Reinhard; Pereira, Nuno; Silva, Vitor
Role of Large Balancing Areas In Integrating Solar Generation: Solar Integration Series. 3 of 3 (Brochure)
The third out of a series of three fact sheets describing the role of large balancing areas in integrating solar generation.
Not Available
Rapid Daytime Estimation of Cloud Properties over a Large Area from Radiance Distributions
An algorithm is developed to rapidly estimate cloud properties for a large area from daytime imager data. In this context, a large area refers to a grid cell composed of many imager pixels. The algorithm assumes a gamma distribution to model the ...
Andrew K. Heidinger
Hierarchical extraction of critical area for shorts in very large ICs
This paper describes an algorithm for efficiently extracting critical area in large VLSI circuits. The algorithm, implemented to handle shorts between electrical nets, takes advantage of the available hierarchy in the layout description in order to speed-up ... Keywords: CREST software, IC design, VLSI, circuit layout CAD, critical area extraction, hierarchical extraction, integrated circuit layout, large VLSI circuits, layout description, shorts, very large ICs
P. K. Nag; W. Maly
High resolution telescope
A large effective-aperture, low-cost optical telescope with diffraction-limited resolution enables ground-based observation of near-earth space objects. The telescope has a non-redundant, thinned-aperture array in a center-mount, single-structure space frame. It employs speckle interferometric imaging to achieve diffraction-limited resolution. The signal-to-noise ratio problem is mitigated by moving the wavelength of operation to the near-IR, and the image is sensed by a Silicon CCD. The steerable, single-structure array presents a constant pupil. The center-mount, radar-like mount enables low-earth orbit space objects to be tracked as well as increases stiffness of the space frame. In the preferred embodiment, the array has elemental telescopes with subaperture of 2.1m in a circle-of-nine configuration. The telescope array has an effective aperture of 12m which provides a diffraction-limited resolution of 0.02 arc seconds. Pathlength matching of the telescope array is maintained by an electro-optical system employing laser metrology. Speckle imaging relaxes pathlength matching tolerance by one order of magnitude as compared to phased arrays. Many features of the telescope contribute to substantial reduction in costs. These include eliminating the conventional protective dome and reducing on-site construction activities. The cost of the telescope scales with the first power of the aperture rather than its third power as in conventional telescopes. 9 figs., 1 tab.
Massie, N.A.; Oster, Y.
A large effective-aperture, low-cost optical telescope with diffraction-limited resolution enables ground-based observation of near-earth space objects. The telescope has a non-redundant, thinned-aperture array in a center-mount, single-structure space frame. It employs speckle interferometric imaging to achieve diffraction-limited resolution. The signal-to-noise ratio problem is mitigated by moving the wavelength of operation to the near-IR, and the image is sensed by a Silicon CCD. The steerable, single-structure array presents a constant pupil. The center-mount, radar-like mount enables low-earth orbit space objects to be tracked as well as increases stiffness of the space frame. In the preferred embodiment, the array has elemental telescopes with subaperture of 2.1 m in a circle-of-nine configuration. The telescope array has an effective aperture of 12 m which provides a diffraction-limited resolution of 0.02 arc seconds. Pathlength matching of the telescope array is maintained by an electro-optical system employing laser metrology. Speckle imaging relaxes pathlength matching tolerance by one order of magnitude as compared to phased arrays. Many features of the telescope contribute to substantial reduction in costs. These include eliminating the conventional protective dome and reducing on-site construction activites. The cost of the telescope scales with the first power of the aperture rather than its third power as in conventional telescopes.
Massie, Norbert A. (San Ramon, CA); Oster, Yale (Danville, CA)
A direct thin-film path towards low-cost large-area III-V ...
A direct thin-film path towards low-cost large-area III-V ... depending on the surface energy constraints of the nucleation ... scaling all times in ...
Iron (III) Chloride doping of large-area chemical vapor deposition graphene
Chemical doping is an effective method of reducing the sheet resistance of graphene. This thesis aims to develop an effective method of doping large area Chemical Vapor Deposition (CVD) graphene using Iron (III) Chloride ...
Song, Yi, S.M. Massachusetts Institute of Technology
A Very Large Telescope imaging and spectroscopic survey of the Wolf-Rayet population in NGC 7793
We present a VLT/FORS1 imaging and spectroscopic survey of the Wolf-Rayet (WR) population in the Sculptor group spiral galaxy NGC 7793. We identify 74 emission line candidates from archival narrow-band imaging, from which 39 were observed with the Multi Object Spectroscopy (MOS) mode of FORS1. 85% of these sources displayed WR features. Additional slits were used to observe HII regions, enabling an estimate of the metallicity gradient of NGC 7793 using strong line calibrations, from which a central oxygen content of log (O/H) + 12 = 8.6 was obtained, falling to 8.25 at R_25. We have estimated WR populations using a calibration of line luminosities of Large Magellanic Cloud stars, revealing ~27 WN and ~25 WC stars from 29 sources spectroscopically observed. Photometric properties of the remaining candidates suggest an additional ~27 WN and ~8 WC stars. A comparison with the WR census of the LMC suggests that our imaging survey has identified 80% of WN stars and 90% for the WC subclass. Allowing for incompleten...
Bibby, J L
NIST Telescope Calibration May Help Explain Mystery of ...
... They will use this information to calibrate a much larger telescope–the Large Synoptic Survey Telescope, planned for construction in Chile. ...
Beam Test of a Large Area nonn Silicon Strip Detector with Fast Binary Readout Electronics
Beam Test of a Large Area nÂonÂn Silicon Strip Detector with Fast Binary Readout Electronics Y test was carried out for the nonÂirradiated and the irradiated detector modules. Efficiency, noise occupancy and performance in the edge regions were analyzed using the beam test data. High efficiency
Beam Test of a Large Area nÂonÂn Silicon Strip Detector with Fast Binary Readout Electronics Y modules was irradiated with protons to a fluence of 1.2 Ă? 10 14 p/cm 2 . A beam test was carried out in the edge regions were analyzed using the beam test data. High efficiency both for the non
Origination of nano- and microstructures on large areas by interference lithography
Many markets require large area surface relief micro- and nanostructures. Important examples are light management structures for display applications or the radiation power management in solar systems. Structuring techniques with both up-scaling and ... Keywords: Display technology, Interference lithography, Nanoimprint lithography, Replication, Solar cells
Andreas J. Wolf; Hubert Hauser; Volker KüBler; Christian Walk; Oliver HöHn; Benedikt BläSi
We present the optical to near-infrared spectrum of MAXI J1659-152 during the onset of its 2010 X-ray outburst. The spectrum was obtained with X-shooter on the ESO Very Large Telescope early in the outburst simultaneous with high-quality observations at both shorter and longer wavelengths. At the time of the observations, the source was in the low-hard state. The X-shooter spectrum includes many broad ({approx}2000 km s{sup -1}), double-peaked emission profiles of H, He I, and He II, characteristic signatures of a low-mass X-ray binary during outburst. We detect no spectral signatures of the low-mass companion star. The strength of the diffuse interstellar bands results in a lower limit to the total interstellar extinction of A{sub V} {approx_equal} 0.4 mag. Using the neutral hydrogen column density obtained from the X-ray spectrum we estimate A{sub V} {approx_equal} 1 mag. The radial velocity structure of the interstellar Na I D and Ca II H and K lines results in a lower limit to the distance of {approx}4 {+-} 1 kpc, consistent with previous estimates. With this distance and A{sub V} , the dereddened spectral energy distribution represents a flat disk spectrum. The two 10 minute X-shooter spectra show significant variability in the red wing of the emission-line profiles, indicating a global change in the density structure of the disk, though on a timescale much shorter than the typical viscous timescale of the disk.
Kaur, Ramanpreet; Kaper, Lex; Ellerbroek, Lucas E.; Russell, David M.; Altamirano, Diego; Wijnands, Rudy; Yang Yijung; Van der Horst, Alexander; Van der Klis, Michiel [Astronomical Institute 'Anton Pannekoek', University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands); D'Avanzo, Paolo [INAF, Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807 Merate (Italy); De Ugarte Postigo, Antonio; Fynbo, Johan P. U. [Dark Cosmology Centre, Niels Bohr Institute, Juliane Maries Vej 30, Copenhagen 2100 (Denmark); Flores, Hector [GEPI, Paris Observatory, CNRS, University of Paris-Diderot, 5 Place Jules Janssen, 92195 Meudon (France); Goldoni, Paolo [Laboratoire Astroparticule et Cosmologie, 10 rue A. Domon et L. Duquet, 75205 Paris Cedex 13 (France); Thoene, Christina C. [IAA-CSIC, Glorieta de la Astronomia s/n, 18008 Granada (Spain); Kouveliotou, Chryssa [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Wiersema, Klaas [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Kuulkers, Erik, E-mail: firstname.lastname@example.com [European Space Agency, European Space Astronomy Centre, P.O. Box 78, 28691 Villanueva de la Canada, Madrid (Spain)
Multifunctionality and control of the crumpling and unfolding of large-area graphene
Crumpled graphene films are widely used, for instance in electronics1, energy storage2,3, composites4,5 and biomedicine6. Although it is known that the degree of crumpling affects graphene's properties and the performance of graphene-based devices and materials3,5,7, the controlled folding and unfolding of crumpled graphene films has not been demonstrated. Here we report an approach to reversibly control the crumpling and unfolding of large-area graphene sheets. We show with experiments, atomistic simulations and theory that, by harnessing the mechanical instabilities of graphene adhered on a biaxially pre-stretched polymer substrate and by controlling the relaxation of the pre-strains in a particular order, graphene films can be crumpled into tailored self-organized hierarchical structures that mimic superhydrophobic leaves. The approach enables us to fabricate large-area conductive coatings and electrodes
Jianfeng Zang; Seunghwa Ryu; Nicola Pugno; Qiming Wang; Qing Tu; Markus J. Buehler; Xuanhe Zhao
The European Large Area ISO Survey - ISOPHOT results using the MPIA-pipeline
The European Large Area ISO Survey (ELAIS) will provide Infrared observations of 4 regions in the sky with ISO. Around 2000 Infrared sources have been detected at 7 and 15 microns (with ISOCAM), 90 and 175 microns (with ISOPHOT)) over 13 square degrees of the sky. We present the source extraction pipeline of the 90 microns ISOPHOT observations, describe and discuss the results obtained and derive the limits of the ELAIS observational strategy.
C. Surace; P. Heraudeau; D. Lemke; S. Oliver; M. Rowan-Robinson; the ELAIS consortium
Caustic Recycle from Hanford Tank Waste Using Large Area NaSICON Structures (LANS)
This report presents the results of a 5-day test of an electrochemical bench-scale apparatus using a proprietary (NAS-GY) material formulation of a (Na) Super Ion Conductor (NaSICON) membrane in a Large Area NaSICON Structures (LANS) configuration. The primary objectives of this work were to assess system performance, membrane seal integrity, and material degradation while removing Na from Group 5 and 6 tank waste from the Hanford Site.
Fountain, Matthew S.; Sevigny, Gary J.; Balagopal, S.; Bhavaraju, S.
Development of process to transfer large areas of LPCVD graphene from copper foil to a porous support substrate
In this thesis, I present a procedure by which to transfer greater than 25 mm˛ areas of high-quality graphene synthesized via low-pressure chemical vapor deposition from copper foil to porous support substrates. Large-area, ...
O'Hern, Sean C. (Sean Carson)
Further advancements for large area-detector based computed tomography system
We present advancements made to a large area-detector based system for industrial x-ray computed tomography. Past performance improvements in data acquisition speeds were made by use of high-resolution large area, flat-panel amorphous-silicon (a-Si) detectors. The detectors have proven, over several years, to be a robust alternative to CCD-optics and image intensifier CT systems. These detectors also provide the advantage of area detection as compared with the single slice geometry of linear array systems. New advancements in this system include parallel processing of sinogram reconstructions, improved visualization software and migration to frame-rate a-Si detectors. Parallel processing provides significant speed improvements for data reconstruction, and is implemented for parallel-beam, fan-beam and Feldkamp cone-beam reconstruction algorithms. Reconstruction times are reduced by an order of magnitude by use of a cluster of ten or more equal-speed computers. Advancements in data visualization are made through interactive software, which allows interrogation of the full three-dimensional dataset. Inspection examples presented in this paper include an electromechanical device, a nonliving biological specimen and a press-cast plastic specimen. We also present a commonplace item for the benefit of the layperson.
Davis, A. W. (Anthony W.); Keating, S. C. (Scott C.); Claytor, T. N. (Thomas N.)
The characterization of secondary electron emitters for use in large area photo-detectors.
The Large-Area Picosecond Photo-Detector Project is focused on the development of large-area systems to measure the time-of-arrival of relativistic particles with, ultimately, 1 pico-second resolution, and for signals typical of Positron-Emission Tomography (PET), a resolution of about 30 pico-seconds. Our contribution to this project is to help with identification and efficient fabrication of novel electron emitting materials with properties optimized for use in such detectors. We have assembled several techniques into a single ultra-high vacuum apparatus in order to enable characterization of both photocathode and secondary electron emission (SEE) materials. This apparatus will examine how photocathode quantum efficiency and SEE material electron yield correlate to surface chemical composition, state, and band structure. The techniques employed in this undertaking are X-ray photoelectron spectroscopy (XPS) for surface chemical composition, ultraviolet photoelectron spectroscopy (UPS) for the determination of band structure and surface work function, as well surface cleaning techniques such as argon-ion sputtering. To determine secondary electron emission yields and quantum efficiencies of detector materials, we use electron optics from a low energy electron diffraction (LEED) system whose set of hemispherical electrodes allows for efficient collection of secondary and photo electrons. As we gain a stronger insight into the details of mechanisms of electron emission from photocathodes and SEE materials, we will be able to lay a foundation for the larger collaborative effort to design the next generation of large-area photo-detectors. We present our preliminary results on the SEE materials from our as-yet completed characterization system.
Jokela, S. J.; Veryovkin, I. V.; Zinovev, A. V.; Frisch, H. J.; Elam, J. W.; Peng, Q.; Mane, A. U. (Energy Systems); ( MSD); (Univ. of Chicago)
Characterization of a commercially available large area, high detection efficiency single-photon avalanche diode
We characterize a new commercial, back-illuminated reach-through silicon single-photon avalanche photo diode (SPAD) SAP500 (Laser Components. Inc.), operated in Geiger-mode for purpose of photon counting. We show that for this sensor a significant interplay exists between dark counts, detection efficiency, afterpulsing, excess voltage and operating temperature, sometimes requiring a careful optimization tailored for a specific application. We find that a large flat plateau of sensitive area of about 0.5 mm in diameter, a peak quantum efficiency of 73% at 560 nm and timing precision down to 150 ps FWHM are the main distinguishing characteristics of this SPAD.
Stip?evi?, Mario; Ursin, Rupert
Development of large-area monolithically integrated silicon-film photovoltaic modules
This report describes work to develop Silicon-Film Product III into a low-cost, stable device for large-scale terrestrial power applications. The Product III structure is a thin (< 100 {mu}m) polycrystalline silicon layer on a non-conductive supporting ceramic substrate. The presence of the substrate allows cells to be isolated and in interconnected monolithically in various series/parallel configurations. The long-term goal for the product is efficiencies over 18% on areas greater than 1200 cm{sup 2}. The high efficiency is made possible through the benefits of using polycrystalline thin silicon incorporated into a light-trapping structure with a passivated back surface. Short-term goals focused on the development of large-area ceramics, a monolithic interconnection process, and 100 cm{sup 2} solar cells. Critical elements of the monolithically integrated device were developed, and an insulating ceramic substrate was developed and tested. A monolithic interconnection process was developed that will isolate and interconnect individual cells on the ceramic surface. Production-based, low-cost process steps were used, and the process was verified using free-standing silicon wafers to achieve an open-circuit voltage (V{sub oc}) of 8.25 V over a 17-element string. The overall efficiency of the silicon-film materials was limited to 6% by impurities. Improved processing and feedstock materials are under investigation.
Rand, J.A.; Bacon, C.; Cotter, J.E.; Lampros, T.H.; Ingram, A.E.; Ruffins, T.R.; Hall, R.B.; Barnett, A.M. (AstroPower, Inc., Newark, DE (United States))
Advances in large-area Hg1-xCdxTe photovoltaic detectors for remote-sensing applications
State-of-the-art large-area photovoltaic (PV) detectors fabricated in HgCdTe grown by molecular beam epitaxy (MBE) have been demonstrated for the Crosstrack Infrared Sounder (CrIS) instrument. Large-area devices (1 mm in diameter) yielded excellent electrical ... Keywords: HgCdTe, crosstrack infrared sounder, molecular beam epitaxy (MBE), photovoltaic detectors, remote sensing
P. S. Wijewarnasuriya; M. Zandian; J. Phillips; D. Edwall; R. E. Dewames; G. Hildebrandt; J. Bajaj; J. M. Arias; A. I. D'Souza; F. Moore
Development of Large area Gamma-ray Camera with GSO(Ce) Scintillator Arrays and PSPMTs
We have developed a position-sensitive scintillation camera with a large area absorber for use as an advanced Compton gamma-ray camera. At first we tested GSO(Ce) crystals. We compared light output from the GSO(Ce) crystals under various conditions: the method of surface polishing, the concentration of Ce, and co-doping Zr. As a result, we chose the GSO(Ce) crystals doped with only 0.5 mol% Ce, and its surface polished by chemical etching as the scintillator of our camera. We also made a 16$\\times$16 cm$^2$ scintillation camera which consisted of 9 position-sensitive PMTs (PSPMTs Hamamatsu flat-panel H8500), the each of which had 8$\\times$8 anodes with a pitch of 6 mm and coupled to 8$\\times$8 arrays of pixelated 6$\\times6\\times$13 mm$^3$ GSO(Ce) scintillators. For the readout system of the 576 anodes of the PMTs, we used chained resistors to reduce the number of readout channels down to 48 to reduce power consumption. The camera has a position resolution of less than 6mm and a typical energy resolution of 10.5% (FWHM) at 662 keV at each pixel in a large area of 16$\\times$16 cm$^2$. %to choose the best scintillator for our project. Furthermore we constructed a 16$\\times$16 array of 3$\\times3\\times$13 mm$^3$ pixelated GSO(Ce) scintillators, and glued it to a PMT H8500. This camera had the position resolution of less than 3mm, over an area of 5$\\times$5 cm$^2$, except for some of the edge pixels; the energy resolution was typically 13% (FWHM) at 662 keV.
H. Nishimura; K. Hattori; H. Kubo; T. Tanimori
Initial Results of ISCO for a Large TCE DNAPL Source Area
This paper will describe the results of an in situ chemical oxidation (ISCO) remedial action currently in progress to address subsurface contamination by trichloroethene (TCE) dense nonaqueous phase liquid (DNAPL). The U.S. Department of Energy is responsible for the cleanup of environmental media at the Portsmouth Gaseous Diffusion Plant (PORTS) in southern Ohio. The X-701B Solid Waste Management Unit is an unlined surface impoundment at PORTS which was operated from 1954 to 1988. A TCE plume in groundwater emanates from the unit and is approximately 2,200 feet in length. Metals, radioactive inorganics, and other organic chemicals are also present at lower concentrations in the groundwater. An ongoing 1.6-acre TCE DNAPL source area for the plume is believed to exist up-gradient in the vicinity of the X-701B pond. The extent of the source area is inferred from actual recovery of DNAPL in production wells and from detection of TCE concentrations between 100 and 1,000 mg/L in monitoring wells. Previous remedial activities at X-701B have included a Resource Conservation and Recovery Act (RCRA) closure and a technology demonstration that recirculated permanganate solutions between two horizontal wells. Results of sampling after these remedial activities showed that the permanganate effectively destroyed TCE in portions of the aquifer where adequate contact was achieved, but that uniform distribution by the recirculation system was problematic. As a result, the TCE concentration in the groundwater eventually rebounded after the treatment. To overcome distribution issues and to more aggressively remediate the source, a new remediation approach is being implemented for the unit. The new approach involves the injection of Modified Fenton's Reagent directly into the source area using temporary direct push injection points. This new approach provides the ability to overcome limitations imposed by heterogeneities in the subsurface by injecting relatively small quantities of reagent into a large number of temporary injection points across the source area. These injections are then repeated, as necessary, on a grid pattern until performance goals are achieved. The remediation is being implemented in four phases under a work plan approved by the Ohio Environmental Protection Agency. Phase I, the pilot test, was conducted over a small portion of the source area. Phase II currently involves full-scale treatment of the source area. In Phase III, the source area will be monitored for TCE rebound. Phase IV will involve limited treatment for the down-gradient portion of the plume. (authors)
Thompson, S.L.; Cross, P.E. [CDM, Piketon, OH (United States)
Operational experience of a large area x-ray camera for protein crystallography.
After 3 years experience of operating very large area (210mm x 210mm) CCD-based detectors at the Advanced Photon Source, operational experience is reported. Four such detectors have been built, two for Structural Biology Center (APS-1 and SBC-2), one for Basic Energy Sciences Synchrotrons Radiation Center (Gold-2) at Argonne National Laboratory's Advanced Photon Source and one for Osaka University by Oxford Instruments, for use at Spring 8 (PX-21O). The detector is specifically designed as a high resolution and fast readout camera for macromolecular crystallography. Design trade-offs for speed and size are reviewed in light of operational experience and future requirements are considered. Operational data and examples of crystallography data are presented, together with plans for more development.
Joachimiak, A.; Jorden, A. R.; Loeffen, P. W.; Naday, I.; Sanishvili, R.; Westbrook, E. M.
Large area ceramic thin films on plastics: A versatile route via solution processing
A new general route for large area, submicron thick ceramic thin films (crystalline metal oxide thin films) on plastic substrates is presented, where the crystallization of films is guaranteed by a firing process. Gel films are deposited on silicon substrates with a release layer and fired to be ceramic films, followed by transferring onto plastic substrates using adhesives. The ceramic films thus fabricated on plastics exhibit a certain degree of flexibility, implying the possibility of the technique to be applied to high-throughput roll-to-roll processes. Using this technique, we successfully realized transparent anatase thin films that provide high optical reflectance and transparent indium tin oxide thin films that exhibit electrical conductivity on polycarbonate and acrylic resin substrates, respectively. Crystallographically oriented zinc oxide films and patterned zinc oxide films are also demonstrated to be realized on acrylic resin substrates.
Kozuka, H.; Yamano, A.; Uchiyama, H.; Takahashi, M. [Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35 Yamate-cho, Suita, 564-8680 (Japan); Fukui, T.; Yoki, M.; Akase, T. [Graduate School of Science and Engineering, Kansai University, 3-3-35 Yamate-cho, Suita, 564-8680 (Japan)
Large area directly heated lanthanum hexaboride cathode structure having predetermined emission profile
A large area directly heated lanthanum hexaboride (LaB/sub 6/) cathode system is disclosed. The system comprises a LaB/sub 6/ cathode element generally circular in shape about a central axis. The cathode element has a head with an upper substantially planar emission surface, and a lower downwardly and an intermediate body portion which diminishes in cross-section from the head towards the base of the cathode element. A central rod is connected to the base of the cathode element and extends along the central axis. Plural upstanding spring fingers are urged against an outer peripheral contact surface of the head end to provide a mechanical and electrical connection to the cathode element. 7 figs
Leung, Ka-Ngo; Gordon, K.C.; Kippenhan, D.O.; Purgalis, P.; Moussa, D.; Williams, M.D.; Wilde, S.B.; West, M.W.
Large area quasi-free standing monolayer graphene on 3C-SiC(111)
Large scale, homogeneous quasi-free standing monolayer graphene is obtained on cubic silicon carbide, i.e., the 3C-SiC(111) surface, which represents an appealing and cost effective platform for graphene growth. The quasi-free monolayer is produced by intercalation of hydrogen under the interfacial, (6{radical}(3)x6{radical}(3))R30 deg.-reconstructed carbon layer. After intercalation, angle resolved photoemission spectroscopy reveals sharp linear {pi}-bands. The decoupling of graphene from the substrate is identified by x-ray photoemission spectroscopy and low energy electron diffraction. Atomic force microscopy and low energy electron microscopy demonstrate that homogeneous monolayer domains extend over areas of hundreds of square-micrometers.
Coletti, C. [Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstr. 1, D-70569 Stuttgart (Germany); Center for Nanotechnology Innovation and NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12, 56127 Pisa (Italy); Emtsev, K. V.; Starke, U. [Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstr. 1, D-70569 Stuttgart (Germany); Zakharov, A. A. [MAX-Lab, Lund University, Box 118, Lund S-22100 (Sweden); Ouisse, T.; Chaussende, D. [Laboratoire des Materiaux et du Genie Physique-CNRS UMR5628--Grenoble INP, Minatec 3 parvis Louis Neel, BP 257, 38016 Grenoble (France)
The development of large area saturable Bragg reflectors for the generation of widely-tunable ultra-short pulses
This thesis focuses on the realization of two photonic devices; 1) semiconductor lasers and 2) large area broadband Saturable Bragg Reflectors (SBRs). Semiconductor lasers explore the use of 3D and 2D quantum confinement ...
Nabanja, Sheila P
On the Potential Impact of Irrigated Areas in North America on Summer Rainfall Caused by Large-Scale Systems
The potential impact of the increase in irrigated areas in North America during the past 100 years on summer rainfall associated with medium- to large-scale precipitation systems is evaluated conceptually and by several illustrative numerical ...
M. Segal; Z. Pan; R. W. Turner; E. S. Takle
Large-Area Quality Control of Atomically-Thin Layered Materials
vapor deposition (LPCVD), on doped Si. We transferred the HOPG pillars by applying a large compression
Nolen, Craig Merten
Novel Large Area High Resolution Neutron Detector for the Spallation Neutron Source
Neutron scattering is a powerful technique that is critically important for materials science and structural biology applications. The knowledge gained from past developments has resulted in far-reaching advances in engineering, pharmaceutical and biotechnology industries, to name a few. New facilities for neutron generation at much higher flux, such as the SNS at Oak Ridge, TN, will greatly enhance the capabilities of neutron scattering, with benefits that extend to many fields and include, for example, development of improved drug therapies and materials that are stronger, longer-lasting, and more impact-resistant. In order to fully realize this enhanced potential, however, higher neutron rates must be met with improved detection capabilities, particularly higher count rate capability in large size detectors, while maintaining practicality. We have developed a neutron detector with the technical and economic advantages to accomplish this goal. This new detector has a large sensitive area, offers 3D spatial resolution, high sensitivity and high count rate capability, and it is economical and practical to produce. The proposed detector technology is based on B-10 thin film conversion of neutrons in long straw-like gas detectors. A stack of many such detectors, each 1 meter in length, and 4 mm in diameter, has a stopping power that exceeds that of He-3 gas, contained at practical pressures within an area detector. With simple electronic readout methods, straw detector arrays can provide spatial resolution of 4 mm FWHM or better, and since an array detector of such form consists of several thousand individual elements per square meter, count rates in a 1 m^2 detector can reach 2?10^7 cps. Moreover, each individual event can be timetagged with a time resolution of less than 0.1 ?sec, allowing accurate identification of neutron energy by time of flight. Considering basic elemental cost, this novel neutron imaging detector can be commercially produced economically, probably at a small fraction of the cost of He-3 detectors. In addition to neutron scattering science, the fully developed base technology can be used as a rugged, low-cost neutron detector in area monitoring and surveying. Radiation monitors are used in a number of other settings for occupational and environmental radiation safety. Such a detector can also be used in environmental monitoring and remote nuclear power plant monitoring. For example, the Department of Energy could use it to characterize nuclear waste dumps, coordinate clean-up efforts, and assess the radioactive contaminants in the air and water. Radiation monitors can be used to monitor the age and component breakdown of nuclear warheads and to distinguish between weapons and reactor grade plutonium. The UN's International Atomic Energy Agency (IAEA) uses radiation monitors for treaty verification, remote monitoring, and enforcing the non-proliferation of nuclear weapons. As part of treaty verification, monitors can be used to certify the contents of containers during inspections. They could be used for portal monitoring to secure border checkpoints, sea ports, air cargo centers, public parks, sporting venues, and key government buildings. Currently, only 2% of all sea cargo shipped is inspected for radiation sources. In addition, merely the presence of radiation is detected and nothing is known about the radioactive source until further testing. The utilization of radiation monitors with neutron sensitivity and capability of operation in hostile port environments would increase the capacity and effectiveness of the radioactive scanning processes.
Lacy, Jeffrey L
LSA large area silicon sheet task continuous Czochralski process development. Final report
A commercial Czochralski crystal growing furnace was converted to a continuous growth facility by installation of a small, in-situ premelter with attendant silicon storage and transport mechanisms. The premelter was situated immediately over the primary melt and provided a molten silicon flow into the large crucible simultaneously as crystal was being grown. The key element in this continuous Czochralski process is the premelter and a substantial portion of the program involved its evolution into a workable design. The best arrangement tested was a vertical, cylindrical graphite heater containing a small fused quartz test tube liner from which the molten silicon flowed out the bottom. Approximately 83 cm of nominal 5-cm diameter crystal was grown with continuous melt addition furnished by the test tube premelter. High-perfection crystal was not obtained, however, due primarily to particulate contamination of the melt. A major contributor to the particulate problem was severe silicon oxide buildup on the premelter which would ultimately drop into the primary melt. Elimination of this oxide buildup will require extensive study and experimentation and the ultimate success of continuous Czochralski depends on a successful solution to this problem. Economic modeling of the continuous Czochralski process utilized the IPEG option of SAMICS. The influence of both crystal size and total furnace run size were examined. Results of these studies indicate that for 10-cm diameter crystal, 100-kg furnace runs of four or five crystals each are near optimal. Costs tend to asymptote at the 100-kg level so little additional cost improvement occurs at larger runs. For these conditions, crystal cost in equivalent wafer area of around $16/m/sup 2/ exclusive of polysilicon and slicing is obtained. Lower crystal costs can be obtained by growing larger diameter crystal in the 12 to 15-cm range.
Rea, S.N.
Cooperative Large Area Surveillance with a Team of Aerial Mobile Robots for Long Endurance Missions
This paper proposes a distributed approach to solve long duration area surveillance missions with a team of aerial robots, taking into account communication constraints. The system, based on "one-to-one" coordination, minimizes the probability that any ... Keywords: Area surveillance, Cooperation, Coordination, Decentralized systems, Long endurance missions, Multi-UAS systems
Jose Joaquin Acevedo; Begońa C. Arrue; Ivan Maza; Anibal Ollero
Method of making large area conformable shape structures for detector/sensor applications using glass drawing technique and postprocessing
A method of making a large area conformable shape structure comprises drawing a plurality of tubes to form a plurality of drawn tubes, and cutting the plurality of drawn tubes into cut drawn tubes of a predetermined shape. The cut drawn tubes have a first end and a second end along the longitudinal direction of the cut drawn tubes. The method further comprises conforming the first end of the cut drawn tubes into a predetermined curve to form the large area conformable shape structure, wherein the cut drawn tubes contain a material.
Ivanov, Ilia N. (Knoxville, TN); Simpson, John T. (Clinton, IN)
Research on stable, high-efficiency, large-area amorphous silicon based modules -- Task B
This report documents progress in developing a stable, high- efficiency, four-terminal hybrid tandem module. The module consists of a semi-transparent, thin-film silicon:hydrogen alloy (TFS) top circuit and a copper indium diselenide (CuInSe{sub 2}) bottom circuit. Film deposition and patterning processes were successfully extended to 0.4-m{sup 2} substrates. A 33.2-W (8.4% efficient) module with a 3970-cm{sup 2} aperture area and a white back reflector was demonstrated; without the back reflector, the module produced 30.2 W (7.6% efficient). Placing a laminated, 31.6-W, 8.1%-efficient CuInSe{sub 2} module underneath this TFS module, with an air gap between the two, produces 11.2 W (2.9% efficient) over a 3883-cm{sup 2} aperture area. Therefore, the four-terminal tandem power output is 41.4 W, translating to a 10.5% aperture-area efficiency. Subsequently, a 37.8-W (9.7% aperture-area efficiency) CuInSe{sub 2} module was demonstrated with a 3905-cm{sup 2} aperture area. Future performances of single-junction and tandem modules of this size were modeled, and predicted power outputs exceed 50 W (13% efficient) for CuInSe{sub 2} and 65 W (17% efficient) for TFS/CuInSe{sub 2} tandem modules.
Mitchell, K.W.; Willet, D.R. (Siemens Solar Industries, Camarillo, CA (USA))
{100} or 45.degree.-rotated {100}, semiconductor-based, large-area, flexible, electronic devices
Novel articles and methods to fabricate the same resulting in flexible, {100} or 45.degree.-rotated {100} oriented, semiconductor-based, electronic devices are disclosed. Potential applications of resulting articles are in areas of photovoltaic devices, flat-panel displays, thermophotovoltaic devices, ferroelectric devices, light emitting diode devices, computer hard disc drive devices, magnetoresistance based devices, photoluminescence based devices, non-volatile memory devices, dielectric devices, thermoelectric devices and quantum dot laser devices.
Research on stable, high-efficiency, large-area, amorphous-silicon-based submodules
The primary objective of this subcontract is to develop the technology for same bandgap, amorphous silicon tandem junction photovoltaic modules having an area of at least 900 cm{sup 2} with the goal of achieving an aperture area efficiency of 9%. A further objective is to demonstrate modules that retain 95% of their under standard light soaking conditions. Our approach to the attainment of these objective is based on the following distinctive technologies: (a) in-house deposition of SiO{sub 2}/SnO{sub 2}:F onto soda lime glass by APCVD to provide a textured, transparent electrode, (b) single chamber r.f. flow discharge deposition of the a-Si:H layers onto vertical substrates contained with high package density in a box carrier'' to which the discharge is confined (c) sputter deposition of highly reflecting, ZnO-based back contacts, and (d) laser scribing of the a-Si:H and electrodes with real-time scribe tracking to minimize area loss. Continued development of single junction amorphous silicon was aggressively pursued as proving ground for various optical enhancement schemes, new p-layers, and i-layers quality. We have rigorously demonstrated that the introduction of a transitional i-layer does not impair stability and that the initial gain in performance is retained. We have demonstrated a small improvement in cell stability through a post-fabrication treatment consisting of multiple, intense light flashes followed by sufficient annealing. Finally, several experiments have indicated that long term stability can be improved by overcoating the SnO{sub 2} with ZnO. 25 refs., 17 figs.
Delahoy, A.E.; Tonon, T.; Macneil, J. (Chronar Corp., Princeton, NJ (USA))
Testing and evaluation of large-area heliostats for solar thermal applications
Two heliostats representing the state-of-the-art in glass-metal designs for central receiver (and photovoltaic tracking) applications were tested and evaluated at the National Solar Thermal Test Facility in Albuquerque, New Mexico from 1986 to 1992. These heliostats have collection areas of 148 and 200 m{sup 2} and represent low-cost designs for heliostats that employ glass-metal mirrors. The evaluation encompassed the performance and operational characteristics of the heliostats, and examined heliostat beam quality, the effect of elevated winds on beam quality, heliostat drives and controls, mirror module reflectance and durability, and the overall operational and maintenance characteristics of the two heliostats. A comprehensive presentation of the results of these and other tests is presented. The results are prefaced by a review of the development (in the United States) of heliostat technology.
Strachan, J.W.; Houser, R.M.
The First VERITAS Telescope
The first atmospheric Cherenkov telescope of VERITAS (the Very Energetic Radiation Imaging Telescope Array System) has been in operation since February 2005. We present here a technical description of the instrument and a summary of its performance. The calibration methods are described, along with the results of Monte Carlo simulations of the telescope and comparisons between real and simulated data. The analysis of TeV $\\gamma$-ray observations of the Crab Nebula, including the reconstructed energy spectrum, is shown to give results consistent with earlier measurements. The telescope is operating as expected and has met or exceeded all design specifications.
J. Holder; R. W. Atkins; H. M. Badran; G. Blaylock; S. M. Bradbury; J. H. Buckley; K. L. Byrum; D. A. Carter-Lewis; O. Celik; Y. C. K. Chow; P. Cogan; W. Cui; M. K. Daniel; I. de la Calle Perez; C. Dowdall; P. Dowkontt; C. Duke; A. D. Falcone; S. J. Fegan; J. P. Finley; P. Fortin; L. F. Fortson; K. Gibbs; G. Gillanders; O. J. Glidewell; J. Grube; K. J. Gutierrez; G. Gyuk; J. Hall; D. Hanna; E. Hays; D. Horan; S. B. Hughes; T. B. Humensky; A. Imran; I. Jung; P. Kaaret; G. E. Kenny; D. Kieda; J. Kildea; J. Knapp; H. Krawczynski; F. Krennrich; M. J. Lang; S. LeBohec; E. Linton; E. K. Little; G. Maier; H. Manseri; A. Milovanovic; P. Moriarty; R. Mukherjee; P. A. Ogden; R. A. Ong; J. S. Perkins; F. Pizlo; M. Pohl; J. Quinn; K. Ragan; P. T. Reynolds; E. T. Roache; H. J. Rose; M. Schroedter; G. H. Sembroski; G. Sleege; D. Steele; S. P. Swordy; A. Syson; J. A. Toner; L. Valcarcel; V. V. Vassiliev; S. P. Wakely; T. C. Weekes; R. J. White; D. A. Williams; R. Wagner
Fabrication of stable, large-area, thin-film CdTe photovoltaic modules
Solar Cells, Inc (SCI) has a program to produce 60 cm X 120 cm solar modules based on CdTe films. The method of choice for semiconductor deposition is condensation from high temperature vapor's. Early work focussed on Close Spaced Sublimation and Chemical Vapor Deposition using elemental sources, but later equipment designs no longer strictly conform to either category. Small area efficiency has been confirmed by NREL at 9.3% on a 0.22 cm{sup 2} device (825 mV Voc, 18.2 mA/cm{sup 2} Jsc, and 0.62 FF) deposited on a 100 cm{sup 2} substrate. On 8 cell, 64 cm{sup 2} submodules, the best result to date is 7.3% (5.9 V Voc, 130 mA Isc, and 0.61 FF). CdS, CdTe, and ZnTe films have been deposited onto 60 cm X 120 cm substrates - single cells produced from this material have exceeded 8% efficiency, 64 cm{sup 2} submodules have exceeded 5%. Module efficiency is limited by mechanical defects - mostly shunts - associated with processing after deposition of the semiconductor layer's. Present best result is 1.4% total area efficiency. In anticipation of more advanced designs, CdTe films have also been deposited from apparatus employing elemental sources. This project is in an early stage and has produced only rudimentary results. A pro-active Safety, Health, Environmental and Disposal program has been developed. Results to date indicate that both employees and the environment have been protected against overexposure to hazards including toxic chemicals.
Nolan, J.F.; Meyers, P.V. (Solar Cells, Inc., Toledo, OH (United States))
Apparatus and method for rapid cooling of large area substrates in vacuum
The present invention is directed to an apparatus and method for rapid cooling of a large substrate in a vacuum environment. A first cooled plate is brought into close proximity with one surface of a flat substrate. The spatial volume between the first cooling plate and the substrate is sealed and brought to a higher pressure than the surrounding vacuum level to increase the cooling efficiency. A second cooled plate is brought into close proximity with the opposite surface of the flat substrate. A second spatial volume between the second cooling plate and the substrate is sealed and the gas pressure is equalized to the gas pressure in the first spatial volume. The equalization of the gas pressure on both sides of the flat substrate eliminates deflection of the substrate and bending stress in the substrate.
Barth, Kurt L.; Enzenroth, Robert A.; Sampath, Walajabad S.
Continuous Czochralski process development. LSSA large area silicon sheet task. Annual report, October 1977--September 1978
A Czochralski crystal growing furnace was converted to a continuous growth facility by installation of a premelter to provide molten silicon flow into the primary crucible. The basic furnace is operational and several trial crystals have been grown in the batch mode. The key element in this continuous Czochralski process is the premelter and considerable effort has been expended in developing a suitable design. Numerous premelter configurations have been tested both in laboratory-scale equipment as well as in the actual furnace. The best arrangement tested to date is a vertical, cylindrical graphite heater containing small fused silicon test tube liner in which the incoming silicon is melted and flows into the primary crucible. The premelter is positioned immediately over the primary melt. Economic modeling of the continuous Czochralski process has continued utilizing the IPEG option of SAMICS. The influence of both crystal size and total furnace run size have been examined. Results of these studies indicate that for 10-cm diameter crystal, 100-kg furnace runs of four or five crystals each are near-optimal. Costs tend to asymptote at the 100-kg level so little additional cost improvement occurs at larger runs. For these conditions, crystal cost in equivalent wafer area of around $20/m/sup 2/ exclusive of polysilicon and slicing is obtained.
Large area silicon sheet by EFG. Second quarterly report, April 1, 1977--June 30, 1977
During the quarter on which this document reports significant amounts of 2'' wide ribbon have been grown from both growth systems at speeds up to 2''/min. Solar cells prepared from the material have shown conversion efficiencies up to 8% (AM1). Thus, it is believed that the basic effort to produce reasonably clean conditions in these resistance heated furnaces has succeeded. However, the ribbons produced show a cross-sectional structure which is significantly different from that of induction furnace grown ribbon (1'' wide at a rate of 1''/min). Also, the ribbon produced in this program has unusually large inhomogeneities across its width. Some hypotheses to explain both of these features are advanced and the possible implications for solar cell performance are touched upon. The multiple ribbon growth system (JPL No. 3A) has shown a number of flaws with respect to the reliability of the basic furnace design. These definitely need to be rectified before any significant demonstration of multiple ribbon growth can proceed. The cartridges, however, have performed quite well. The work on 3'' cartridge design and automatic controls has proceeded nearly on schedule and the report contains a detailed description of the approach and the equipment to be used for automatic control of ribbon width.
Wald, F.V.
Large area silicon sheet by EFG. Second quarterly report, April 1-June 30, 1979
In Furnace No. 1 during this quarter, experiments were conducted in which the total argon purge rate in this furnace was decreased. A number of extremely significant changes in the crystallographic structure and electronic quality of the ribbons were observed in these experiments. Ribbon segments were grown in which the equilibrium defect structure was no longer present and the electrical properties improved to the extent that cells of 50 cm/sup 2/ area having AM1 efficiencies over 11% could be prepared. In Furnace No. 3A, the final five-ribbon demonstration run was performed. The furnace performed nearly flawlessly over the 15 hour run during which approx. 30 meters of 5 cm wide ribbon were grown at a rate of approx. 3.3 cm/min from each of the five cartridges. Initial evaluation of a small lot of 45 cm/sup 2/ solar cells of approx. 9% (AM1) efficiency. Subsequent to this final multiple demonstration run, the furnace was converted to be operated with three 10 cm width cartridges, plus a melt replenishment unit. This conversion is now complete, and the first growth runs using one cartridge and the melt replenisher have produced approx. 4 meters of 10 cm wide ribbon at a growth rate of 3.5 cm/min. In Furnace 17, work on stress has continued, and a basic investigation of stress and buckle generation in the ribbon has shown this to be a fairly complex problem at high growth rates. However, at rates up to perhaps 5 cm/min, the problem may be manageable through improvements in puller design and ribbon guidance. Also on this machine, the work with automatic control designs is making progress, and in an appendix to this report, a very comprehensive discussion of the control dynamics during EFG growth is provided.
Large-area Silicon-Film{trademark} panels and solar cells. Phase 2 technical report, January 1996--December 1996
The Silicon-Film{trademark} process is on an accelerated path to large-scale manufacturing. A key element in that development is optimizing the specific geometry of both the Silicon-Film{trademark} sheet and the resulting solar cell. That decision has been influenced by cost factors, engineering concerns, and marketing issues. The geometry investigation has focused first on sheet nominally 15 cm wide. This sheet generated solar cells with areas of 240 cm{sup 2} and 675 cm{sup 2}. Most recently, a new sheet fabrication machine was constructed that produces Silicon-Film{trademark} with a width in excess of 30 cm. Test results have indicated that there is no limit to the width of sheet generated by this process. The new wide material has led to prototype solar cells with areas of 300, 400, and 1,800 cm{sup 2}. Significant advances in solar-cell processing have been developed in support of fabricating large-area devices, including uniform emitter diffusion and anti-reflection coatings.
Rand, J.A.; Barnett, A.M.; Checchi, J.C.; Culik, J.S.; Collins, S.R.; Ford, D.H.; Hall, R.B.; Jackson, E.L.; Kendall, C.L. [AstroPower Inc., Newark, DE (United States)
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
AREA AREA FAQ # Question Response 316 vs DCAA FAQ 1 An inquiry from CH about an SBIR recipient asking if a DCAA audit is sufficient to comply with the regulation or if they need to add this to their audit they have performed yearly by a public accounting firm. 316 audits are essentially A-133 audits for for-profit entities. They DO NOT replace DCAA or other audits requested by DOE to look at indirect rates or incurred costs or closeouts. DCAA would never agree to perform A-133 or our 316 audits. They don't do A-133 audits for DOD awardees. The purpose of the audits are different, look at different things and in the few instances of overlap, from different perspectives. 316
Large area, high spatial resolution tracker for new generation of high luminosity experiments in Hall A at Jefferson Lab
In 2014 the CEBAF electron accelerator at Jefferson Lab (JLab) will deliver a longitudinally polarized (up to 85%), high intensity (up to 100 ?A) beam with maximum energy of 12 GeV, twice the present value. To exploit the new opportunities that the energy upgrade will offer, a new spectrometer (Super BigBite - SBS) is under development, featuring very forward angle, large acceptance and ability to operate in high luminosity environment. The tracking system of SBS will consist of large area (40×150 cm2 and 50×200 cm2), high spatial resolution (better than 100 ?m) chambers based on the GEM technology and 2 small (10×20 cm) Silicon Strip Detector planes. The design of the GEM chambers and its sub-components such as the readout electronics is resented here.
Bellini, V; Castelluccio, D; Colilli, S; Cisbani, E; De Leo, R; Fratoni, R; Frullani, S; Garibaldi, F; Guiliani, F; Guisa, A; Gricia, M; Lucentini, M; Meddi, F; Minutoli, S; Musico, P; Noto, F; De Oliveira, R; Santavenere, F; Sutera, M C
Construction and testing of large-area CPC-collector and comparison with a flat plate collector
A 13.6 m{sup 2} east-west aligned CPC-collector(compound parabolic concentrator) with flat absorbers, proposed for use in large-area applications, has been built and tested and compared with a flat plate collector. The performance of the CPC at a working temperature of 50{degree}C over ambient can be described by F`{eta}{sub 0} = 0.75 and F`U{sub L} = 2.5 W m{sup -2} K{sup -1} while the flat plate collector is described by F`{eta}{sub 0} = 0.80, and F`U{sub L} = 3.3 W m{sup -2} K{sup -1}. The large difference in heat loss coefficient is to a large degree explained by absorption of solar radiation in the reflectors in the CPC-collector. The incidence angle dependence of the optical performance of the two collectors showed a similar appearance. Both collector constructions are based on the LGB (long ground based) technology, which allows them to be built in large modules up to 170 m{sup 2}. 12 refs., 6 figs., 1 tab.
Roennelid, M. [Dalarna Univ., Borlaenge (Sweden)] [Dalarna Univ., Borlaenge (Sweden); Perers, B.; Karlsson, B. [Vattenfall Utveckling AB, Aelvkarleby (Sweden)] [Vattenfall Utveckling AB, Aelvkarleby (Sweden)
I scanned the six major astronomical journals of 2008 for all 1589 papers that are based on new data obtained from ground-based optical/IR telescopes worldwide. Then I collected data on numbers of papers, citations to them in 3+ years, the most-cited papers, and annual operating costs. These data are assigned to four groups by telescope aperture. For instance, while the papers from telescopes with an aperture >7 m average 1.29 more citations than those with an aperture of 2 to <4 m, this represents a small return for a factor of four difference in operating costs. Among the 17 papers that have received {>=}100 citations in 3+ years, only half come from the large (>7 m) telescopes. I wonder why the large telescopes do so relatively poorly and suggest possible reasons. I also found that papers based on archival data, such as the Sloan Digital Sky Survey, produce 10.6% as many papers and 20.6% as many citations as those based on new data. Also, the 577.2 papers based on radio data produced 36.3% as many papers and 33.6% as many citations as the 1589 papers based on optical/IR telescopes.
Abt, Helmut A., E-mail: firstname.lastname@example.com [Kitt Peak National Observatory, P.O. Box 26732, Tucson, AZ 85726-6732 (United States)
Large Area Imager
Livermore Lab Report. News Archive. News ... in a search instrument for locating lost or hidden radiation ... is in the final stages of integration ...
Nitrogen actinometry for measurement of nitrogen radical spatial distribution in large-area plasma-enhanced chemical vapor deposition
Density distributions of radicals in the large-area silicon nitride (Si{sub 3}N{sub 4}) plasma-enhanced chemical vapor deposition (PECVD) process were measured using a spatially resolvable optical emission spectrometer (SROES). To determine the qualitative distribution of a target radical, the authors used optical actinometry with nitrogen (N{sub 2}) gas as an actinometer. To compare the SROES data and process results, the thickness of the deposited Si{sub 3}N{sub 4} thin films using an ellipsometer was measured. By introducing nitrogen-based optical actinometry, the authors obtained very good agreement between the experimental results of the distributions of atomic nitrogen radical and the deposited thicknesses of Si{sub 3}N{sub 4} thin films. Based on these experimental results, the uniformity of the process plasma in the PECVD process at different applied radio frequency powers was analyzed.
Oh, Changhoon; Kang, Minwook; Hahn, Jae W. [Nano Photonics Laboratory, School of Mechanical Engineering, Yonsei University, 50 Yonesi-ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Nam, Seungsuk [Based Technology of Equipment Team, LG Display, Paju-City, Gyeonggi-do 413-811 (Korea, Republic of)
Research on high-efficiency, large-area, CuInSe{sub 2}-based thin- film modules. Annual subcontract report, 1 May 1992--15 Aug 1993
This report describes work to demonstrate 12.5% aperture efficient, large-area (3900-cm{sup 2}) encapsulated thin-film CuInSe{sub 2} (CIS) photovoltaic modules. Module design consists of 53 series-connected ZnO/CdS/CIS/Mo/glass cells fabricated on a 4141-cm{sup 2} (128.6 {times} 32.2 cm) glass substrate with a nominal aperture area of 3895 cm{sup 2} (127.3 {times} 30.6 cm). Four CIS modules were shipped to NREL under the terms of the subcontract. Phase 2 consisted of fabricating large-area (3900-cm{sup 2}) modules for high-performance module processing. The large-area parts proved to be cumbersome, and we decided to use smaller substrates (100 cm{sup 2}) to accelerate the progress in solving the types of technical challenges that were discovered in processing large-area parts, and then to apply these solutions to larger areas to meet the objectives of the investigation. Most critical issues determining module yield losses can be grouped into three major categories: (1) Uniformity and reproducibility of the absorber formation process dominates the fundamental performance of the material over a large area, (2) interaction of the substrate with the Mm requires appropriate selection criterial and preparation techniques for minimizing defects that lead to shunting and areas of poor photoresponse, and (3) performance losses near interconnects reduce module performance and can cause inadequate performance through module durability testing.
Knapp, K.E.; Gay, R.R. [Siemens Solar Industries, Camarillo, CA (United States)
Deployment of a Pair of 3 M telescopes in Utah
Two 3 m telescopes are being installed in Grantsville Utah. They are intended for the testing of various approaches to the implementation of intensity interferometry using Cherenkov Telescopes in large arrays as receivers as well as for the testing of novel technology cameras and electronics for ground based gamma-ray astronomy.
Finnegan, G.; Adams, B.; Butler, K.; Cardoza, J.; Colin, P.; Hui, C. M.; Kieda, D.; Kirkwood, D.; Kress, D.; Kress, M.; LeBohec, S.; McGuire, C.; Newbold, M.; Nunez, P.; Pham, K. [University of Utah, Department of Physics, Salt Lake City, Utah 84112 (United States)
Searching for Transient Pulses with the ETA Radio Telescope
Array-based, direct-sampling radio telescopes have computational and communication requirements unsuited to conventional computer and cluster architectures. Synchronization must be strictly maintained across a large number of parallel data streams, from ... Keywords: Direct sampling radio telescope array, FPGA cluster computing, RFI mitigation, signal dedispersion
C. D. Patterson; S. W. Ellingson; B. S. Martin; K. Deshpande; J. H. Simonetti; M. Kavic; S. E. Cutchin
Mirror Development for the Cherenkov Telescope Array
The Cherenkov Telescope Array (CTA) is a planned observatory for very-high energy gamma-ray astronomy. It will consist of several tens of telescopes of different sizes, with a total mirror area of up to 10,000 square meters. Most mirrors of current installations are either polished glass mirrors or diamond-turned aluminium mirrors, both labour intensive technologies. For CTA, several new technologies for a fast and cost-efficient production of light-weight and reliable mirror substrates have been developed and industrial pre-production has started for most of them. In addition, new or improved aluminium-based and dielectric surface coatings have been developed to increase the reflectance over the lifetime of the mirrors compared to those of current Cherenkov telescope instruments.
Förster, A; Baba, H; Bähr, J; Bonardi, A; Bonnoli, G; Brun, P; Canestrari, R; Chadwick, P; Chikawa, M; Carton, P -H; De Souza, V; Dipold, J; Doro, M; Durand, D; Dyrda, M; Giro, E; Glicenstein, J -F; Hanabata, Y; Hayashida, M; Hrabovski, M; Jeanney, C; Kagaya, M; Katagiri, H; Lessio, L; MANDAT, D; Mariotti, M; Medina, C; Micha?owski, J; Micolon, P; Nakajima, D; Niemiec, J; Nozato, A; Palatka, M; Pareschi, G; Pech, M; Peyaud, B; Pühlhofer, G; Rataj, M; Rodeghiero, G; Rojas, G; Rousselle, J; Sakonaka, R; Schovanek, P; Seweryn, K; Schultz, C; Shu, S; Stinzing, F; Stodulski, M; Teshima, M; Travniczek, P; Van Eldik, C; Vassiliev, V; Wi?niewski, ?; Wörnlein, A; Yoshida, T
Large-area, triple-junction a-Si alloy production scale-up. Semiannual subcontract report, 17 March 1993--18 September 1993
This report describes work to improve the efficiency of large-area, multi-junction amorphous silicon (a-Si) alloy modules. Equipment capable of producing modules up to 0.74 m{sup 2} in area is on line and process development has begun. Preliminary cost analysis/reduction has begun to ensure that these development efforts will result in a commercialization of the large-area technology. The approach was to transfer the high-efficiency multi-junction technology from R&D into the manufacturing environment by using three different substrate sizes. Initial attempts to transfer the multijunction silicon process were made using a 0.1-m{sup 2} substrate (approximately 1 ft{sup 2}). These efforts resulted in a module with a measured aperture area efficiency of 10.32%. Simultaneous with the transfer of the silicon technology, the most complicated aspect of the technology transfer, Solarex began process development techniques on large-area modules by using the 0.37-m{sup 2} substrates. These efforts resulted in modules with a total area efficiency of 7%. Finally, initial runs on substrates 0.74 m{sup 2} were made to debug the large-area equipment in preparation of transferring the knowledge gained in the processing of the smaller substrates.
Oswald, R.; O`Dowd, J.; Ashenfelter, W. [Solarex Corp., Newtown, PA (United States). Thin Film Div.] [and others
Cornell Caltech Atacama Telescope (CCAT): a 25 m aperture telescope above 5000 m altitude
Cornell, California Institute of Technology (Caltech), and Jet Propulsion Lab (JPL) have joined together to study development of a 25 meter sub-millimeter telescope (CCAT) on a high peak in the Atacama region of northern Chile, where the atmosphere is so dry as to permit observation at wavelengths as short as 200 micron. The telescope is designed to deliver high efficiency images at that wavelength with a total 1/2 wavefront error of about 10 microns. With a 20 arc min field of view, CCAT will be able to accommodate large format bolometer arrays and will excel at carrying out surveys as well as resolving structures to the 2 arc sec. resolution level. The telescope will be an ideal complement to ALMA. Initial instrumentation will include both a wide field bolometer camera and a medium resolution spectrograph. Studies of the major telescope subsystems have been performed as part of an initial Feasibility Concept Study. Novel aspects of the telescope design include kinematic mounting and active positioning of primary mirror segments, high bandwidth secondary mirror segment motion control for chopping, a Calotte style dome of 50 meter diameter, a mount capable of efficient scanning modes of operation, and some new approaches to panel manufacture. Analysis of telescope performance and of key subsystems will be presented to illustrate the technical feasibility and pragmatic cost of CCAT. Project plans include an Engineering Concept Design phase followed by detailed design and development. First Light is planned for early 2012.
Thomas A. Sebring; Riccardo Giovanelli; Simon Radford; Jonas Zmuidzinas
Evaluation of local content strategies to plan large engineering projects in the oil & gas industry in high risk country areas
The Local content of a complex project is an important variable to create value and increase the overall sustainability of large engineering projects in the Oil & Gas industry, especially in the developing countries. The paper proposes a method to ... Keywords: causal knowledge map, large engineering projects, local content, scenario analysis
Troncone Enzo Piermichele; De Falco Massimo; Gallo Mosč; Santillo Liberatina Carmela; Pier Alberto Viecelli
The Animated Gamma-ray Sky Revealed by the Fermi Gamma-ray Space Telescope
The Fermi Gamma-ray Space Telescope has been observing the sky in gamma-rays since August 2008. In addition to breakthrough capabilities in energy coverage (20 MeV-300 GeV) and angular resolution, the wide field of view of the Large Area Telescope enables observations of 20% of the sky at any instant, and of the whole sky every three hours. It has revealed a very animated sky with bright gamma-ray bursts flashing and vanishing in minutes, powerful active galactic nuclei flaring over hours and days, many pulsars twinkling in the Milky Way, and X-ray binaries shimmering along their orbit. Most of these variable sources had not been seen by the Fermi predecessor, EGRET, and the wealth of new data already brings important clues to the origin of the high-energy emission and particles powered by the compact objects. The telescope also brings crisp images of the bright gamma-ray emission produced by cosmic-ray interactions in the interstellar medium, thus allowing to measure the cosmic nuclei and electron spectra across the Galaxy, to weigh interstellar clouds, in particular in the dark-gas phase. The telescope sensitivity at high energy will soon provide useful constraints on dark-matter annihilations in a variety of environments. I will review the current results and future prospects of the Fermi mission.
Grenier, Isabelle (University Paris Diderot and CEA Saclay, France)
The Effect of Urban Street Gang Densities on Small Area Homicide Incidence in a Large Metropolitan County, 1994–2002
43 Two hundred eighty-nine zip code tabulation areas existedWe selected 255 of those zip codes to merge with homicideanalysis. We excluded zip codes with very low populations
Robinson, Paul L.; Boscardin, W. John; George, Sheba M.; Teklehaimanot, Senait; Heslin, Kevin C.; Bluthenthal, Ricky N.
Impact of potential large-scale irrigation on the West African Monsoon and its dependence on location of irrigated area
This study investigates the impact of potential large-scale irrigation on the West African Monsoon using the MIT Regional Climate Model (MRCM). A new irrigation module is implemented to assess the impact of location and scheduling of irrigation on ...
Eun-Soon Im; Marc P. Marcella; Elfatih A. B. Eltahir
The Large-Scale Circulation and Heat Sources over the Tibetan Plateau and Surrounding Areas during the Early Summer of 1979. Part II: Heat and Moisture Budgets
The large-scale heat and moisture budgets over the Tibetan Plateau and surrounding area during a 40-day period from late May to early July 1979 are studied using the FGGE Level II-b data. During this period the general circulation over East Asia ...
Huibang Luo; Michio Yanai
The Large-Scale Circulation and Heat Sources over the Tibetan Plateau and Surrounding Areas during the Early Summer of 1979. Part I: Precipitation and Kinematic Analyses
The time evolution of the large-scale precipitation, low-level (850 mb) wind, moisture and vertical motion fields over the Tibetan Plateau and surrounding areas during a 40-day period from late May to early July 1979 is studied based on the ...
Volcanic Ash Transport from Mount Asama to the Tokyo Metropolitan Area Influenced by Large-Scale Local Wind Circulation
The eruption of the Mount Asama volcano on 16 September 2004 produced an ash cloud and led to ashfall in the Tokyo metropolitan area that lies on the Kanto Plain. Satellite images showed the ash cloud drifting toward the south in the morning but ...
Nobumitsu Tsunematsu; Tomohiro Nagai; Toshiyuki Murayama; Ahoro Adachi; Yasuhiro Murayama
The TACTIC atmospheric Cherenkov Imaging telescope
The TACTIC $\\gamma$-ray telescope, equipped with a light collector of area $\\sim$9.5m$^2$ and a medium resolution imaging camera of 349-pixels, has been in operation at Mt.Abu, India since 2001. This paper describes the main features of its various subsystems and its overall performance with regard to (a) tracking accuracy of its 2-axes drive system, (b) spot size of the light collector, (c) back-end signal processing electronics and topological trigger generation scheme, (d) data acquisition and control system and (e) relative and absolute gain calibration methodology. Using a trigger field of view of 11$\\times$11 pixels ($\\sim$ 3.4$^\\circ$$\\times3.4^\\circ$), the telescope records a cosmic ray event rate of $\\sim$2.5 Hz at a typical zenith angle of 15$^\\circ$. Monte Carlo simulation results are also presented in the paper for comparing the expected performance of the telescope with actual observational results. The consistent detection of a steady signal from the Crab Nebula above $\\sim$1.2 TeV energy, at a sensitivity level of $\\sim5.0\\sigma$ in $\\sim$25 h, alongwith excellent matching of its energy spectrum with that obtained by other groups, reassures that the performance of the TACTIC telescope is quite stable and reliable. Furthermore, encouraged by the detection of strong $\\gamma$-ray signals from Mrk 501 (during 1997 and 2006 observations) and Mrk 421 (during 2001 and 2005-2006 observations), we believe that there is considerable scope for the TACTIC telescope to monitor similar TeV $\\gamma$-ray emission activity from other active galactic nuclei on a long term basis.
R. Koul; A. K. Tickoo; S. K. Kaul; S. R. Kaul; N. Kumar; K. K. Yadav; N. Bhatt; K. Venugopal; H. C. Goyal; M. Kothari; P. Chandra; R. C. Rannot; V. K. Dhar; M. K. Koul; R. K. Kaul; S. Kotwal; K. Chanchalani; S. Thoudam; N. Chouhan; M. Sharma; S. Bhattacharyya; S. Sahayanathan
Geomagnetic Effects on the Performance of Atmospheric Cerenkov Telescopes
Atmospheric Cerenkov telescopes are used to detect electromagnetic showers from primary gamma rays of energy > 300 GeV and to discriminate these from cascades due to hadrons using the shape and orientation of the Cerenkov images. The geomagnetic field affects the development of showers and diffuses and distorts the images. When the component of the field normal to the shower axis is sufficiently large (> 0.4 G) the performance of gamma ray telescopes may be affected.
P. M. Chadwick; K. Lyons; T. J. L. McComb; K. J. Orford; J. L. Osborne; S. M. Rayner; S. E. Shaw; K. E. Turver
{100}<100> or 45.degree.-rotated {100}<100>, semiconductor-based, large-area, flexible, electronic devices
Novel articles and methods to fabricate the same resulting in flexible, {100}<100> or 45.degree.-rotated {100}<100> oriented, semiconductor-based, electronic devices are disclosed. Potential applications of resulting articles are in areas of photovoltaic devices, flat-panel displays, thermophotovoltaic devices, ferroelectric devices, light emitting diode devices, computer hard disc drive devices, magnetoresistance based devices, photoluminescence based devices, non-volatile memory devices, dielectric devices, thermoelectric devices and quantum dot laser devices.
Large-area, triple-junction a-Si alloy production scale-up. Semiannual subcontract report, 17 March 1994--18 September 1994
This report describes work performed under a 3-y subcontract to advance Solarex`s photovoltaic manufacturing technologies, reduce its a-Si:H module production costs, increase module performance, and expand the Solarex commercial production capacity. During this period, Solarex focused on improving deposition of the front contact, investigating alternate feedstocks for the front contact, maximizing throughput and area utilization for all laser scribes, optimizing a-Si:H deposition equipment to achieve uniform deposition over large areas, optimizing the triple-junction module fabrication process, evaluating the materials to deposit the rear contact, and optimizing the combination of isolation scribe and encapsulant to pass the wet high potential test.
Oswald, R.; Morris, J. [Solarex Corp., Newtown, PA (United States). Thin Film Div.
Fermi Gamma-ray Space Telescope: High-Energy Results from the First Year
The Fermi Gamma-ray Space Telescope (Fermi) was launched on June 11, 2008 and began its first year sky survey on August 11, 2008. The Large Area Telescope (LAT), a wide field-of-view pair-conversion telescope covering the energy range from 20 MeV to more than 300 GeV, is the primary instrument on Fermi. While this review focuses on results obtained with the LAT, the Gamma-ray Burst Monitor (GBM) complements the LAT in its observations of transient sources and is sensitive to X-rays and gamma-rays with energies between 8 keV and 40 MeV. During the first year in orbit, the Fermi LAT has observed a large number of sources that include active galaxies, pulsars, compact binaries, globular clusters, supernova remnants, as well as the Sun, the Moon and the Earth. The GBM and LAT together have uncovered surprising characteristics in the high-energy emission of gamma-ray bursts (GRBs) that have been used to set significant new limits on violations of Lorentz invariance. The Fermi LAT has also made important new measurements of the Galactic diffuse radiation and has made precise measurements of the spectrum of cosmic-ray electrons and positrons from 20 GeV to 1 TeV.
Peter F. Michelson; William B. Atwood; Steven Ritz
Wide Field Hard X-ray Survey Telescope: ProtoEXIST1
We report our progress on the development of pixellated imaging CZT detector arrays for our first-generation balloon-borne wide-field hard X-ray (20 - 600 keV) telescope, ProtoEXIST1. Our ProtoEXIST program is a pathfinder for the High Energy Telescope (HET) on the Energetic X-ray Imaging Survey telescope (EXIST), a proposed implementation of the Black Hole Finder Probe. ProtoEXIST1 consists of four independent coded-aperture telescopes with close-tiled (~0.4 mm gaps) CZT detectors that preserve their 2.5mm pixel pitch. Multiple shielding/field-of-view configurations are planned to identify optimal geometry for the HET in EXIST. The primary technical challenge in ProtoEXIST is the development of large area, close-tiled modules of imaging CZT detectors (1000 cm2 for ProtoEXIST1), with all readout and control systems for the ASIC readout vertically stacked. We describe the overall telescope configuration of ProtoEXIST1 and review the current development status of the CZT detectors, from individual detector crystal units (DCUs) to a full detector module (DM). We have built the first units of each component for the detector plane and have completed a few Rev2 DCUs (2x2 cm2), which are under a series of tests. Bare DCUs (pre-crystal bonding) show high, uniform ASIC yield (~70%) and ~30% reduction in electronics noise compared to the Rev1 equivalent. A Rev1 DCU already achieved ~1.2% FWHM at 662 keV, and preliminary analysis of the initial radiation tests on a Rev2 DCU shows ~ 4 keV FWHM at 60 keV (vs. 4.7 keV for Rev1). We therefore expect about <~1% FWHM at 662 keV with the Rev2 detectors.
J. Hong; J. E. Grindlay; N. Chammas; B. Allen; A. Copete; B. Said; M. Burke; J. Howell; T. Gauron; R. G. Baker; S. D. Barthelmy; S. Sheikh; N. Gehrels; W. R. Cook; J. A. Burnham; F. A. Harrison; J. Collins; S. Labov; A. Garson III; H. Krawczynski
An Innovative Approach for the Calculation of Exposure Point Concentrations for Large Areas of Surface Radionuclide Contamination
The Department of Energy Rocky Flats site was designated as a wildlife refuge by the Rocky Flats National Wildlife Refuge Act of 2001. Rocky Flats was considered to be one of the most highly contaminated radiological sites in the country. Some portions of the site have low-level radionuclide contamination in surface soils. A site-wide risk and dose assessment to evaluate threats to human health and the environment were performed, so that the site could be released for this land use. The aggressive accelerated action program combined with defensible and innovative risk assessment methods resulted in there being no radionuclides of concern in the final comprehensive risk assessment (DOE 2006). An innovative approach for delineating functional exposure areas and area-weighted exposure point concentration-activities (EPCs) was negotiated with the regulatory agencies in Colorado. This procedure leads to realistic estimates of risk and dose to workers and visitors. This innovative approach to the calculation of EPCs was negotiated with both State and Federal regulators. The value of developing and maintaining good working relationships with regulators responsible for a site can not be overestimated. The building of trust and confidence among responsible parties and regulators is essential for the development and implementation of innovative methods and technologies.
Winchester Chromec, F.; Myers, Jeffrey C. [7800 E. Union Avenue, Denver, Colorado, 801237 (United States)
The suitability of large area drift chambers as the technology choice for the Cosmic Ray Inspection and Passive Tomography (CRIPT) project
The CRIPT project brings together several Canadian institutions, concerned with the detection of Special Nuclear Materials (SNM), addressing a requirement at ports-of-entry for detection of SNM in the many thousands of containers that flow into and out of Canada every day, while at the same time providing a way of monitoring the contents of nuclear waste storage containers, for waste management and non-proliferation reasons. The scale of these applications is large - typically tens of cubic metres, requiring detectors that can cover a large area at a minimum cost. The CRIPT project considered drift chambers adapted from high energy physics experience, as one of its technology choices. We report here on the performance of a full scale prototype, which covers an area of 2.4 m x 1.2 m with only 6 readout channels, and provides a 2D data point with accuracies (in x and z) of around 2 mm. (authors)
Anghel, V. [Atomic Energy Canada Ltd., Chalk River, ON K0J 1J0 (Canada); Armitage, J. [Carleton Univ., Ottawa, ON (Canada); Botte, J.; Boudjemline, K. [Carleton Univ., Ottawa, ON (Canada); Bryman, D.; Bueno, J. [Advanced Applied Physics Solutions, Vancouver, BC (Canada); Charles, E. [Canadian Border Services Agency, Ottawa, ON K1A 0L8 (Canada); Cousins, T. [International Safety Research, Ottawa, ON K2E 7J6 (Canada); Erlandson, A. [Carleton Univ., Ottawa, ON (Canada); Gallant, G. [Canadian Border Services Agency, Ottawa, ON K1A 0L8 (Canada); Jewett, C.; Jonkmans, G. [Atomic Energy Canada Ltd., Chalk River, ON K0J 1J0 (Canada); Liu, Z. [Advanced Applied Physics Solutions, Vancouver, BC (Canada); Noel, S. [International Safety Research, Ottawa, ON K2E 7J6 (Canada); Oakham, F. G. [Carleton Univ., Ottawa, ON (Canada); Stocki, T. J. [Health Canada, Ottawa, ON K1A 0K9 (Canada); Thompson, M. [Atomic Energy Canada Ltd., Chalk River, ON K0J 1J0 (Canada); Waller, D. [Defence Research Development Canada, Ottawa, ON K1A 0Z4 (Canada)
methods. The poly-Si solar cell structure and the performance have been examined. In principle, the new process is potentially applicable to produce large-area thin-film poly-Si solar cells at a high throughput and low cost. A critical issue in this process is to prevent the excessive dopant diffusion during crystallization. Process parameters and the cell structure have to be optimized to achieve the production goal.
Yue Kuo
Construction and Performance of Large-Area Triple-GEM Prototypes for Future Upgrades of the CMS Forward Muon System
At present, part of the forward RPC muon system of the CMS detector at the CERN LHC remains uninstrumented in the high-\\eta region. An international collaboration is investigating the possibility of covering the 1.6 radiation hardness, these micro-pattern gas detectors are an appealing option for simultaneously enhancing muon tracking and triggering capabilities in a future upgrade of the CMS detector. A general overview of this feasibility study will be presented. The design and construction of small (10\\times10 cm2) and full-size trapezoidal (1\\times0.5 m2) triple-GEM prototypes will be described. During detector assembly, different techniques for stretching the GEM foils were tested. Results from measurements with x-rays and from test beam campaigns at the CERN SPS will be shown for the small and large prototypes. Preliminary simulation studies on the expected muon reconstruction and trigger performances of this proposed upgraded muon system will be reported.
M. Tytgat; A. Marinov; N. Zaganidis; Y. Ban; J. Cai; H. Teng; A. Mohapatra; T. Moulik; M. Abbrescia; A. Colaleo; G. de Robertis; F. Loddo; M. Maggi; S. Nuzzo; S. A. Tupputi; L. Benussi; S. Bianco; S. Colafranceschi; D. Piccolo; G. Raffone; G. Saviano; M. G. Bagliesi; R. Cecchi; G. Magazzu; E. Oliveri; N. Turini; T. Fruboes; D. Abbaneo; C. Armagnaud; P. Aspell; S. Bally; U. Berzano; J. Bos; K. Bunkowski; J. P. Chatelain; J. Christiansen; A. Conde Garcia; E. David; R. De Oliveira; S. Duarte Pinto; S. Ferry; F. Formenti; L. Franconi; A. Marchioro; K. Mehta; J. Merlin; M. V. Nemallapudi; H. Postema; A. Rodrigues; L. Ropelewski; A. Sharma; N. Smilkjovic; M. Villa; M. Zientek; A. Gutierrez; P. E. Karchin; K. Gnanvo; M. Hohlmann; M. J. Staib
International Conference on Accelerator and Large Experimental...
and Large Experimental Physics Control Systems Covering control system topics for accelerators, telescopes, fusion, physics detectors, space exploration, and more Proceedings...
A Large-Area Cross-Correlation Study of High Galactic Latutude Soft and Hard X-ray Skies
We have made cross-correlation analyses of (2 -- 15 keV) HEAO A2 and 1 keV ROSAT PSPC All-Sky Survey maps over a selected area ($\\sim$ 4000 deg$^2$) with high galactic latitude (b>40 deg). We have calculated the correlations for the bright ROSAT sources and residual background separately with the \\HEAO A2 TOT (2 -- 10 keV) and HRD (5 -- 15 keV) maps. The amplitude of the bright \\ROSAT source -- A2 CCFs are consistent with expectations from model populations of AGNs and clusters of galaxies, which emit in both bands. However, the residual ROSAT background -- A2 CCFs amplitude at zero degree are about a factor of three larger than that expected from the model populations. Our soft-hard zero-lag and angular CCF results have been compared with the 1 keV auto-correlation function (ACF) found by Soltan et al. (1995) for the same ROSAT data. Their significant angular CCF at a scale of ACF has a hot plasma spectrum with kT\\sim 2 keV, contribution of this component is consistent with both our zero-lag CCF in excess of the population synthesis model prediction and the upper-limit to the angular CCF at \\theta \\sim 2.5 deg. On the other hand, if this component has a lower temperature or a steeper spectrum, a major modification to the population synthesis model and/or an introduction of new classes would be needed.
Takamitsu Miyaji; Guenther Hasinger; Roland Egger; Joachim Truemper; Michael J. Freyberg
Extending the Sensitivity of Air Cerenkov Telescopes
Over the last decade, the Imaging Air Cerenkov technique has proven itself to be an extremely powerful means to study very energetic gamma-radiation from a number of astrophysical sources in a regime which is not practically accessible to satellite-based instruments. The further development of this approach in recent years has generally concentrated on increasing the density of camera pixels, increasing the mirror area and using multiple telescopes. Here we present a practical method to substantially improve the sensitivity of Atmospheric Cerenkov Telescopes using wide-field cameras with a relatively course density of photomultiplier tubes. The 2-telescope design considered here is predicted to be more than ~3 times more sensitive than existing/planned arrays in the regime above 300 GeV for continuously emitting sources; up to ~10 times more sensitive for hour-scale emission (relevant for episodic sources, such as AGN); significantly more sensitive in the regime above 10 TeV; and possessing a sky coverage which is roughly an order of magnitude larger than existing instruments. It should be possible to extend this approach for even further improvement in sensitivity and sky coverage.
I. de la Calle Perez; S. D. Biller
The world-wide telescope
Mining vast databases of astronomical data, this new online way to see the global structure of the universe promises to be not only a wonderful virtual telescope but an archetype for the evolution of computational science.
Jim Gray; Alex Szalay
Optical-level structural modelling of membrane mirrors for spaceborne telescopes
The astronomy and Earth observation communities desire ever-larger space telescopes, but launch costs limit mass and technology limits size. Current research in large aperture mirrors largely supports deployed rigid optics, ...
De Blonk, Brett Jeffrey, 1971-
Fabrication of stable, large-area thin-film CdTe photovoltaic modules. Final subcontract report, May 10, 1991--February 28, 1995
During the period of this subcontract, May 1991 through February 1995, Solar Cells, Inc. has developed and demonstrated a low-cost process to fabricate stable large-area cadmium telluride based thin-film photovoltaic modules. This report summarizes the final phase of the project which is concentrated on process optimization and product life tests. One of the major post-deposition process steps, the CdCl{sub 2} heat treatment, has been experimentally replaced with alternative treatments with vapor chloride or chlorine gas. Material and device qualities associated with alternative treatments are comparable or superior to those with the conventional treatment. Extensive experiments have been conducted to optimize the back-electrode structure in order to ensure long term device stability. Numerous small-area cells and minimodules have been subjected to a variety of stress tests, including but not limited to continuous light soak under open or short circuit or with resistive load, for over 10,000 hours. Satisfactory stability has been demonstrated on 48 cm{sup 2} and 64 cm{sup 2} minimodules under accelerated tests and on 7200 cm{sup 2} large modules under normal operating conditions. The conversion efficiency has also been significantly improved during this period. The total area efficiency of 7200 cm{sup 2} module has reached 8.4%, corresponding to a 60.3W normalized output; the efficiency of 64 cm{sup 2} minimodules and 1.1 cm{sup 2} cells has reached 10.5% (aperture area) and 12.4% (total area), respectively.
Zhou, T.X. [Solar Cells, Inc., Toledo, OH (United States)
Decontamination Strategy for Large Area and/or Equipment Contaminated with Chemical and Biological Agents using a High Energy Arc Lamp (HEAL)
A strategy for the decontamination of large areas and or equipment contaminated with Biological Warfare Agents (BWAs) and Chemical Warfare Agents (CWAs) was demonstrated using a High Energy Arc Lamp (HEAL) photolysis system. This strategy offers an alternative that is potentially quicker, less hazardous, generates far less waste, and is easier to deploy than those currently fielded by the Department of Defense (DoD). For example, for large frame aircraft the United States Air Force still relies on the combination of weathering (stand alone in environment), air washing (fly aircraft) and finally washing the aircraft with Hot Soapy Water (HSW) in an attempt to remove any remaining contamination. This method is laborious, time consuming (upwards of 12+ hours not including decontamination site preparation), and requires large amounts of water (e.g., 1,600+ gallons for a single large frame aircraft), and generates large amounts of hazardous waste requiring disposal. The efficacy of the HEAL system was demonstrated using diisopropyl methyl phosphonate (DIMP) a G series CWA simulant, and Bacillus globigii (BG) a simulant of Bacillus anthracis. Experiments were designed to simulate the energy flux of a field deployable lamp system that could stand-off 17 meters from a 12m2 target area and uniformly expose a surface at 1360 W/m2. The HEAL system in the absence of a catalyst reduced the amount of B. globigii by five orders of magnitude at a starting concentration of 1.63 x 107 spores. In the case of CWA simulants, the HEAL system in the presence of the catalyst TiO2 effectively degraded DIMP sprayed onto a 100mm diameter Petri dish in 5 minutes.
Schoske, Richard [ORNL; Kennedy, Patrick [ORNL; Duty, Chad E [ORNL; Smith, Rob R [ORNL; Huxford, Theodore J [ORNL; Bonavita, Angelo M [ORNL; Engleman, Greg [ORNL; Vass, Arpad Alexander [ORNL; Griest, Wayne H [ORNL; Ilgner, Ralph H [ORNL; Brown, Gilbert M [ORNL
This report describes work performed under a 3-year subcontract to advance Solarex`s photovoltaic (PV) manufacturing technologies, reduce its hydrogenated amorphous silicon (a-Si:H) module production costs, increase module performance, and expand the Solarex commercial production capacity. During the period covered by this report, Solarex focused on (1) improving deposition of the front contact, (2) investigating alternate feed stocks for the front contact, (3) maximizing throughput and area utilization for all laser scribes, (4) optimizing a-Si:H deposition equipment to achieve uniform deposition over large areas, (5) optimizing the triple-junction module fabrication process, (6) evaluating the materials to deposit the rear contact, and (7) optimizing the combination of isolation scribe and encapsulant to pass the wet high-potential test.
Development of large-area monolithically integrated silicon-film photovoltaic modules. Annual subcontract report, 1 May 1991--15 November 1991
Rand, J.A.; Bacon, C.; Cotter, J.E.; Lampros, T.H.; Ingram, A.E.; Ruffins, T.R.; Hall, R.B.; Barnett, A.M. [AstroPower, Inc., Newark, DE (United States)
Photo of the Week: The Webb Telescope's "Golden Spider" | Department of
The Webb Telescope's "Golden Spider" The Webb Telescope's "Golden Spider" Photo of the Week: The Webb Telescope's "Golden Spider" September 14, 2012 - 2:32pm Addthis The James Webb Space Telescope is a large, infrared-optimized telescope that is anticipated to launch in 2018. The spider-like sheets and tubes of wires you see here are the Optical Telescope Simulator (OSIM) for the telescope itself. OSIM will help scientists prepare the Webb telescope for flight by generating a beam of light that the telescope optics will feed into its actual flight instruments. In this photo, engineers have blanketed the OSIM with special insulating material to help control its temperature while it goes into the deep freeze testing of the Space Environment Simulator at NASA's Goddard Space Flight Center in Greenbelt, Maryland. The simulator will mimic the environment that the telescope will experience in operational orbit, more than 1 million miles from Earth. | Photo credit: Chris Gunn/NASA.
Research on high efficiency, large-area CuInSe{sub 2}-based thin-film modules. Annual subcontract report, 1 May 1991--30 April 1992
Objective was to demonstrate 12.5% aperture efficient, large area (3900 cm{sup 2}) encapsulated thin thin CuInSe{sub 2} (CIS) modules. The module design consists of 53 series-connected ZnO/CdS/CIS/Mo/glass cells fabricated on a glass substrate. A baseline characterization of the CIS modules was established during Phase 1. Maps of open circuit voltage provide information on junction quality uniformity. Maps of cell voltages at fixed forward bias show variations in resistance losses due to interconnects. Individual cell I-V curves can be evaluated. Physical nature of defects is correlated using OBIC, EBIC, SEM, tape adhesion, etc. A new world record of 37.7 W and 9.7% aperture efficiency was attained for an encapsulated module; an unencapsulated CIS module plate achieved 40.8 W and 10.5% aperture efficiency.
Mitchell, K.W.; Eberspacher, C. [Siemens Solar Industries, Camarillo, CA (United States)
Task B: Research on stable, high-efficiency, large-area, amorphous-silicon-based submodules: Semiannual subcontract report, 1 February 1987--31 July 1987
This semiannual report presents results of research on stable, high-efficiency, large-area, amorphous-silicon-based submodules. High conversion efficiencies (up to 11.95%) were obtained in small-area, single-junction, a-Si solar cells by using textured tin oxide, superlattice p-layers, graded carbon concentrations near the p-i interface, and highly relective ITO/silver back contacts. Researchers also fabricated single-junction a-SiC and a-SiGe p-i-n cells with efficiencies of 9%--11%. Stacked-junction cells of a-SiC/a-Si, a-SiC/a-SiGe, and a-SiC/a-Si/a-SiGe were fabricated, and efficiencies of about 10% were achieved in some of them. Boron-doped microcrystalline SiC films were developed that contain up to 6 at.% C with conductivities of 3 /times/ 10/sup /minus/3/ ohm /sup /minus/1/ cm/sup /minus/1/ at room temperature and activation energies of 0.11 eV. Stability studies showed that light-induced degradation is usually enhanced by the presence of C grading near the p-i interface. Light-induced degradation of the fill factor of p-i-n cells strongly correlates with optical absorption at 1.2 eV, as measured by photothermal deflection spectroscopy. 11 refs., 70 figs., 16 tabs.
Carlson, D.E.; Arya, R.R.; Bennett, M.S.; Catalano, A.; D'Aiello, R.V.; Dickson, C.R.; Fortmann, C.M.; Goldstein, B.; Morris, J.; Newton, J.L.
Large-area triple-junction a-Si alloy production scaleup. Annual subcontract report, 17 March 1993--18 March 1994
The objective of this subcontract over its three-year duration is to advance Solarex`s photovoltaic manufacturing technologies, reduce its a-Si:H module production costs, increase module performance and expand the Solarex commercial production capacity. Solarex shall meet these objectives by improving the deposition and quality of the transparent front contact, by optimizing the laser patterning process, scaling-up the semiconductor deposition process, improving the back contact deposition, scaling-up and improving the encapsulation and testing of its a-Si:H modules. In the Phase 2 portion of this subcontract, Solarex focused on improving deposition of the front contact, investigating alternate feed stocks for the front contact, maximizing throughput and area utilization for all laser scribes, optimizing a-Si:H deposition equipment to achieve uniform deposition over large-areas, optimizing the triple-junction module fabrication process, evaluating the materials to deposit the rear contact, and optimizing the combination of isolation scribe and encapsulant to pass the wet high potential test. Progress is reported on the following: Front contact development; Laser scribe process development; Amorphous silicon based semiconductor deposition; Rear contact deposition process; Frit/bus/wire/frame; Materials handling; and Environmental test, yield and performance analysis.
SLAC National Accelerator Laboratory - Bringing Telescope Tech...
Telescope Tech to X-ray Lasers By Glenn Roberts Jr July 10, 2012 Technology that helps ground-based telescopes cut through the haze of Earth's atmosphere to get a clearer view of...
The ANTARES neutrino telescope: a status report
ANTARES is a large volume neutrino telescope currently under construction off La Seyne-sur-mer, France, at 2475m depth. Neutrino telescopes aim at detecting neutrinos as a new probe for a sky study at energies greater than 1 TeV. The detection principle relies on the observation, using photomultipliers, of the Cherenkov light emitted by charged leptons induced by neutrino interactions in the surrounding detector medium. Since late January 2007, the ANTARES detector consists of 5 lines, comprising 75 optical detectors each, connected to the shore via a 40 km long undersea cable. The data from these lines not only allow an extensive study of the detector properties but also the reconstruction of downward going cosmic ray muons and the search for the first upward going neutrino induced muons.The operation of these lines follows on from that of the ANTARES instrumentation line, which has provided data for more than a year on the detector stability and the environmental conditions. The full 12 line detector is planned to be fully operational early 2008.
A. Kouchner; for the Antares collaboration
High resolution telescope including an array of elemental telescopes aligned along a common axis and supported on a space frame with a pivot at its geometric center
A large effective-aperture, low-cost optical telescope with diffraction-limited resolution enables ground-based observation of near-earth space objects. The telescope has a non-redundant, thinned-aperture array in a center-mount, single-structure space frame. It employes speckle interferometric imaging to achieve diffraction-limited resolution. The signal-to-noise ratio problem is mitigated by moving the wavelength of operation to the near-IR, and the image is sensed by a Silicon CCD. The steerable, single-structure array presents a constant pupil. The center-mount, radar-like mount enables low-earth orbit space objects to be tracked as well as increases stiffness of the space frame. In the preferred embodiment, the array has elemental telescopes with subaperture of 2.1 m in a circle-of-nine configuration. The telescope array has an effective aperture of 12 m which provides a diffraction-limited resolution of 0.02 arc seconds. Pathlength matching of the telescope array is maintained by a electro-optical system employing laser metrology. Speckle imaging relaxes pathlength matching tolerance by one order of magnitude as compared to phased arrays. Many features of the telescope contribute to substantial reduction in costs. These include eliminating the conventional protective dome and reducing on-site construction activities. The cost of the telescope scales with the first power of the aperture rather than its third power as in conventional telescopes.
Norbert, Massie A. (San Ramon, CA); Yale, Oster (Danville, CA)
A large effective-aperture, low-cost optical telescope with diffraction-limited resolution enables ground-based observation of near-earth space objects. The telescope has a non-redundant, thinned-aperture array in a center-mount, single-structure space frame. It employes speckle interferometric imaging to achieve diffraction-limited resolution. The signal-to-noise ratio problem is mitigated by moving the wavelength of operation to the near-IR, and the image is sensed by a Silicon CCD. The steerable, single-structure array presents a constant pupil. The center-mount, radar-like mount enables low-earth orbit space objects to be tracked as well as increases stiffness of the space frame. In the preferred embodiment, the array has elemental telescopes with subaperture of 2.1 m in a circle-of-nine configuration. The telescope array has an effective aperture of 12 m which provides a diffraction-limited resolution of 0.02 arc seconds. Pathlength matching of the telescope array is maintained by a electro-optical system employing laser metrology. Speckle imaging relaxes pathlength matching tolerance by one order of magnitude as compared to phased arrays. Many features of the telescope contribute to substantial reduction in costs. These include eliminating the conventional protective dome and reducing on-site construction activities. The cost of the telescope scales with the first power of the aperture rather than its third power as in conventional telescopes. 15 figs.
Norbert, M.A.; Yale, O.
Perspectives of a Midrapidity Dimuon Program at RHIC: A Novel and Compact Muon Telescope Detector
We propose a large-area, cost-effective Muon Telescope Detector (MTD) for the Solenoidal Tracker at RHIC (STAR) at mid-rapidity and for the next generation of detectors at a possible electron-ion collider. We utilize Multi-gap Resistive Plate Chambers with large modules and long readout strips (Long-MRPC) in the detector design. The results from cosmic ray and beam tests show the intrinsic timing and spatial resolution for a Long-MRPC are 60-70 ps and $\\sim1$ cm, respectively. The prototype performance of such a novel muon telescope detector at STAR indicates that muon identification at the transverse momentum of a few GeV/$c$ can be achieved through the combined information of track matching with the MTD, ionization energy loss in the Time Projection Chamber, and time-of-flight measurements. A primary muon over secondary muon ratio of better than 1/3 can be achieved. This provides a promising device for future quarkonium programs and primordial dilepton measurements at RHIC. Simulations of the muon efficiency, the signal-to-background ratio of $J/\\psi$, the separation of $\\Upsilon$ 1S from 2S+3S states, and the electron-muon correlation from charm pair production in the RHIC environment are presented.
L. Ruan; G. Lin; Z. Xu; K. Asselta; H. F. Chen; W. Christie; H. J. Crawford; J. Engelage; G. Eppley; T. J. Hallman; C. Li; J. Liu; W. J. Llope; R. Majka; T. Nussbaum; J. Scheblein; M. Shao; R. Soja; Y. Sun; Z. Tang; X. Wang; Y. Wang
The balloonborne large aperture submillimeter telescope G.S. Tucker
., Canada 1A7 i Universidad Puerto Rico, Piedras, Puerto Rico 00931, Received October 2002; received.1--10#. Measure 250--500 lm spectral energy distribu tions (SEDs) colors, from which derive restÂstellar (Class cores associated earliest stages formation. Observe solar system objects including Kuiper belt
Tucker, Gregory S.
A novel thin-film poly-Si fabrication process has been demonstrated. This low thermal budget process transforms the single- and multi-layer amorphous silicon thin films into a poly-Si structure in one simple step over a pulsed rapid thermal annealing process with the enhancement of an ultrathin Ni layer. The complete poly-Si solar cell was fabricated in a short period of time without deteriorating the underneath glass substrate. The unique vertical crystallization process including the mechanism is discussed. Influences of the dopant type and process parameters on crystal structure will be revealed. The poly-Si film structure has been proved using TEM, XRD, Raman, and XPS methods. The poly-Si solar cell structure and the performance have been examined. In principle, the new process is potentially applicable to produce large-area thin-film poly-Si solar cells at a high throughput and low cost. A critical issue in this process is to prevent the excessive dopant diffusion during crystallization. Process parameters and the cell structure have to be optimized to achieve the production goal.
Scientific Potential of Einstein Telescope
Einstein gravitational-wave Telescope (ET) is a design study funded by the European Commission to explore the technological challenges of and scientific benefits from building a third generation gravitational wave detector. The three-year study, which concluded earlier this year, has formulated the conceptual design of an observatory that can support the implementation of new technology for the next two to three decades. The goal of this talk is to introduce the audience to the overall aims and objectives of the project and to enumerate ET's potential to influence our understanding of fundamental physics, astrophysics and cosmology.
B. Sathyaprakash; M. Abernathy; F. Acernese; P. Amaro-Seoane; N. Andersson; K. Arun; F. Barone; B. Barr; M. Barsuglia; M. Beker; N. Beveridge; S. Birindelli; S. Bose; L. Bosi; S. Braccini; C. Bradaschia; T. Bulik; E. Calloni; G. Cella; E. Chassande-Mottin; S. Chelkowski; A. Chincarini; J. Clark; E. Coccia; C. Colacino; J. Colas; A. Cumming; L. Cunningham; E. Cuoco; S. Danilishin; K. Danzmann; R. De. Salvo; T. Dent; R. De. Rosa; L. Di. Fiore; A. Di. Virgilio; M. Doets; V. Fafone; P. Falferi; R. Flaminio; J. Franc; F. Frasconi; A. Freise; D. Friedrich; P. Fulda; J. Gair; G. Gemme; E. Genin; A. Gennai; A. Giazotto; K. Glampedakis; C. Gräf; M. Granata; H. Grote; G. Guidi; A. Gurkovsky; G. Hammond; M. Hannam; J. Harms; D. Heinert; M. Hendry; I. Heng; E. Hennes; S. Hild; J. Hough; S. Husa; S. Huttner; G. Jones; F. Khalili; K. Kokeyama; K. Kokkotas; B. Krishnan; T. G. F. Li; M. Lorenzini; H. Lück; E. Majorana; I. Mandel; V. Mandic; M. Mantovani; I. Martin; C. Michel; Y. Minenkov; N. Morgado; S. Mosca; B. Mours; H. Müller-Ebhardt; P. Murray; R. Nawrodt; J. Nelson; R. Oshaughnessy; C. D. Ott; C. Palomba; A. Paoli; G. Parguez; A. Pasqualetti; R. Passaquieti; D. Passuello; L. Pinard; W. Plastino; R. Poggiani; P. Popolizio; M. Prato; M. Punturo; P. Puppo; D. Rabeling; I. Racz; P. Rapagnani; J. Read; T. Regimbau; H. Rehbein; S. Reid; L. Rezzolla; F. Ricci; F. Richard; A. Rocchi; S. Rowan; A. Rüdiger; L. Santamaria; B. Sassolas; R. Schnabel; C. Schwarz; P. Seidel; A. Sintes; K. Somiya; F. Speirits; K. Strain; S. Strigin; P. Sutton; S. Tarabrin; A. Thüring; J. van den Brand; M van Veggel; C. Van Den Broeck; A. Vecchio; J. Veitch; F. Vetrano; A. Vicere; S. Vyatchanin; B. Willke; G. Woan; K. Yamamoto
Gamma-Hadron Separation Methods for the VERITAS Array of Four Imaging Atmospheric Cherenkov Telescopes
Ground-based arrays of imaging atmospheric Cherenkov telescopes have emerged as the most sensitive gamma-ray detectors in the energy range of about 100 GeV and above. The strengths of these arrays are a very large effective collection area on the order of 100,000 square meter, combined with excellent single photon angular and energy resolutions. The sensitivity of such detectors is limited by statistical fluctuations in the number of Cosmic Ray initiated air showers that resemble gamma-ray air showers in many ways. In this paper, we study the performance of simple event reconstruction methods when applied to simulated data of the Very Energetic Radiation Imaging Telescope Array System (VERITAS) experiment. We review methods for reconstructing the arrival direction and the energy of the primary photons, and examine means to improve on their performance. For a software threshold energy of 300 GeV (100 GeV), the methods achieve point source angular and energy resolutions of sigma[63%]= 0.1 degree (0.2 degree) and sigma[68%]= 15% (22%), respectively. The main emphasis of the paper is the discussion of gamma-hadron separation methods for the VERITAS experiment. We find that the information from several methods can be combined based on a likelihood ratio approach and the resulting algorithm achieves a gamma-hadron suppression with a quality factor that is substantially higher than that achieved with the standard methods used so far.
H. Krawczynski; D. A. Carter-Lewis; C. Duke; J. Holder; G. Maier; S. Le Bohec; G. Sembroski
The ANTARES underwater neutrino telescope
ANTARES is the first undersea neutrino telescope. It is in its complete configuration since May 2008 at about 2.5 km below the sea surface close to Marseille. Data from 12 lines are being analyzed and are producing first results. Here we discuss first analysis results for 5 lines and 10 lines, and we also comment on the performance of the full detector. We show that the detector has capabilities for discriminating upgoing neutrino events from the much larger amount of downgoing atmospheric muons and that data and simulation are in good agreement. We then discuss the physics reach of the detector for what concerns point-like source and dark matter searches.
Teresa Montaruli; for the ANTARES Collaboration
The Timepix Telescope for High Performance Particle Tracking
The Timepix particle tracking telescope has been developed as part of the LHCb VELO Upgrade project, supported by the Medipix Collaboration and the AIDA framework. It is a primary piece of infrastructure for the VELO Upgrade project and is being used for the development of new sensors and front end technologies for several upcoming LHC trackers and vertexing systems. The telescope is designed around the dual capability of the Timepix ASICs to provide information about either the deposited charge or the timing information from tracks traversing the 14 x 14mm matrix of 55 x 55 um pixels. The rate of reconstructed tracks available is optimised by taking advantage of the shutter driven readout architecture of the Timepix chip, operated with existing readout systems. Results of tests conducted in the SPS North Area beam facility at CERN show that the telescope typically provides reconstructed track rates during the beam spills of between 3.5 and 7.5 kHz, depending on beam conditions. The tracks are time stamped with 1 ns resolution with an efficiency of above 98% and provide a pointing resolution at the centre of the telescope of 1.6 um . By dropping the time stamping requirement the rate can be increased to 15 kHz, at the expense of a small increase in background. The telescope infrastructure provides CO2 cooling and a flexible mechanical interface to the device under test, and has been used for a wide range of measurements during the 2011-2012 data taking campaigns.
Kazuyoshi Akiba; Per Arne Ronning; Martin van Beuzekom; Vincent van Beveren; Silvia Borghi; Henk Boterenbrood; Jan Buytaert; Paula Collins; Alvaro Dosil Suarez; Raphael Dumps; Lars Eklund; Daniel Esperante; Abraham Gallas; Hamish Gordon; Bas van der Heijden; Christoph Hombach; Daniel Hynds; Malcolm John; Alexander Leflat; Yi Ming Li; Ian Longstaff; Alexander Morton; Noritsugu Nakatsuka; Andre Nomerotski; Chris Parkes; Eliseo Perez Trigo; Richard Plackett; Matthew M. Reid; Pablo Rodriguez Perez; Heinrich Schindler; Tomasz Szumlak; Panagiotis Tsopelas; Carlos Vazquez Sierra; Jaap Velthuis; Michal Wysokinski
Global and Continental Drought in the Second Half of the Twentieth Century: Severity–Area–Duration Analysis and Temporal Variability of Large-Scale Events
Using observation-driven simulations of global terrestrial hydrology and a cluster algorithm that searches for spatially connected regions of soil moisture, the authors identified 296 large-scale drought events (greater than 500 000 km2 and ...
J. Sheffield; K. M. Andreadis; E. F. Wood; D. P. Lettenmaier
Application of an EMCCD Camera for Calibration of Hard X-Ray Telescopes
Recent technological innovations now make it feasible to construct hard x-ray telescopes for space-based astronomical missions. Focusing optics are capable of improving the sensitivity in the energy range above 10 keV by orders of magnitude compared to previously used instruments. The last decade has seen focusing optics developed for balloon experiments and they will soon be implemented in approved space missions such as the Nuclear Spectroscopic Telescope Array (NuSTAR) and ASTRO-H. The full characterization of x-ray optics for astrophysical and solar imaging missions, including measurement of the point spread function (PSF) as well as scattering and reflectivity properties of substrate coatings, requires a very high spatial resolution, high sensitivity, photon counting and energy discriminating, large area detector. Novel back-thinned Electron Multiplying Charge-Coupled Devices (EMCCDs) are highly suitable detectors for ground-based calibrations. Their chip can be optically coupled to a microcolumnar CsI(Tl) scintillator via a fiberoptic taper. Not only does this device exhibit low noise and high spatial resolution inherent to CCDs, but the EMCCD is also able to handle high frame rates due to its controllable internal gain. Additionally, thick CsI(Tl) yields high detection efficiency for x-rays. This type of detector has already proven to be a unique device very suitable for calibrations in astrophysics: such a camera was used to support the characterization of the performance for all NuSTAR optics. Further optimization will enable similar cameras to be improved and used to calibrate x-ray telescopes for future space missions. In this paper, we discuss the advantages of using an EMCCD to calibrate hard x-ray optics. We will illustrate the promising features of this detector solution using examples of data obtained during the ground calibration of the NuSTAR telescopes performed at Columbia University during 2010/2011. Finally, we give an outlook on ongoing development and optimizations, such as the use of single photon counting mode to enhance spectral resolution.
Vogel, J K; Pivovaroff, M J; Nagarkar, V V; Kudrolli, H; Madsen, K K; Koglin, J E; Christensen, F E; Brejnholt, N F
Module process optimization and device efficiency improvement for stable, low-cost, large-area, cadmium telluride-based photovoltaic module production
This report describes work under a three-year phased subcontract to develop CdS/CdTe devices and modules and to further improve the technology base at Photon Energy, Inc. (PEI) to better address the commercialization issues and objectives of the PEI and the US Department of Energy. During this reporting period we (1) achieved efficiencies of 12.7% on small area devices, (2) achieved 1-ft{sup 2} modules with over 8% aperture-area efficiency (and active area efficiencies up to {approximately}10%), (3) tested 4-ft{sup 2} modules at NREL at 23.1 (21.3) watts, normalized (6.3% efficiency), and (4) found no inherent stability problems with CdTe technology during life testing, at both NREL and PEI. 7 refs.
Albright, S.P.; Ackerman, B.; Chamberlin, R.R.; Jordan, J.F. (Photon Energy, Inc., El Paso, TX (United States))
Fabrication of stable large-area thin-film CdTe photovoltaic modules. Annual subcontract report, 10 May 1992--9 May 1993
This report highlights the progress made by Solar Cells, Inc. (SCI), in its program to produce 60-cm {times} 120-cm solar modules based on CdTe films. During the past year, confirmed efficiency has increased to 10.4% (active area) on a 1 cm{sup 2} cell, 9.8% (aperture area) on a 64-cm{sup 2} 8-cell submodule, and 6.6% (total area) on a 7200-cm{sup 2} module. A module measured in-house had a power output of 53 W, for a total-area efficiency of 7.4%. Average efficiency of modules produced is steadily increasing and standard deviation is decreasing; in a limited run of 12 modules, results were 6.3% ({plus_minus} 0.2%). Field testing has begun; a nominal 1-kW array of 24 modules was set up adjacent to SCI`s facilities. Analysis indicates that present modules are limited in efficiency by shunt resistance and optical absorption losses in the glass superstrate. Loss analysis of present devices allows us to project a module efficiency of 11.8%. A third generation deposition method -- atmospheric pressure elemental vapor deposition (APEVD) has been brought on-line and has produced good quality CdTe. In addition, SCI is expanding its proactive safety, health, environmental, and disposal program dealing with issues surrounding cadmium.
Nolan, J.F.; Meyers, P.V. [Solar Cells, Inc., Toledo, OH (United States)
Measuring Neutrinos with the ANTARES Telescope
The ANTARES underwater neutrino telescope has been taking data since construction began in 2006. The telescope, completed in May of 2008, detects the Cerenkov radiation of charged leptons produced by high energy neutrinos interacting in or around the detector. The lepton trajectory is reconstructed with high precision, revealing the direction of the incoming neutrino. The performance of the detector will be discussed and recent data showing muons, electromagnetic showers and atmospheric neutrinos will be presented. Studies have been underway to search for neutrino point sources in the ANTARES data since 2007. Results from these studies will be presented, and the sensitivity of the telescope will be discussed.
Reed, Corey [National Institute for Subatomic Physics (Nikhef), Amsterdam (Netherlands)
The Effect of Growth Parameters on the Intrinsic Properties of Large-Area Single Layer Graphene Grown by Chemical Vapor Deposition on Cu
We present a comprehensive study of the parameter space for single layer graphene growth by chemical vapor deposition on Cu. The temperature is the most widely recognized parameter in single layer graphene growth. We show that the methane-to-hydrogen ratio and the growth pressure also are critical parameters that affect the structural perfection and the cleanliness of graphene. The optimal conditions for suppressing double and multilayer graphene growth occur near 1000 C, 1:20 methane-to-hydrogen ratio, and a total pressure in the range from 0.5 to 1 Torr. Raman mapping of a 40x30 m2 area shows single layer domains with 5-10 m linear dimensions. Atomic resolution imaging of suspended graphene by aberration corrected scanning transmission electron microscopy shows that the cleanest single layer graphene consists of areas of 10-15 nm linear dimensions and smaller patches of residual contamination that was undetected by other characterization methods.
Regmi, Murari [ORNL; Chisholm, Matthew F [ORNL; Eres, Gyula [ORNL
Delayed fracture of silicon. Silicon sheet growth development for the Large Area Silicon Sheet Task of the Low Cost Silicon Solar Array Project. Final report
Bar specimens were cut from ingots of single crystal silicon, and acid-etched prior to testing. Artificial surface flaws were introduced in specimens by indentation with a Knoop hardness tester. The specimens were loaded in four-point bending to 95% of the nominal fracture stress, while keeping the surface area, containing the flaw, wet with test liquids. No evidence of delayed fracture, and, therefore stress corrosion, of single crystal silicon was observed for liquid environments including water, acetone and aqueous solutions of NaCl, NH/sub 4/OH, and HNO/sub 3/, when tested with a flaw parallel to a (110) surface. The fracture toughness was calculated to be K/sub IC/ = 0.591 x 10/sup 6/ N/m/sup 3/2/.
Chen, T.J.; Knapp, W.J.
Fabrication of stable, large-area, thin-film CdTe photovoltaic modules. Annual subcontract report, 10 May 1991--9 May 1992
Solar Cells, Inc (SCI) has a program to produce 60 cm X 120 cm solar modules based on CdTe films. The method of choice for semiconductor deposition is condensation from high temperature vapor`s. Early work focussed on Close Spaced Sublimation and Chemical Vapor Deposition using elemental sources, but later equipment designs no longer strictly conform to either category. Small area efficiency has been confirmed by NREL at 9.3% on a 0.22 cm{sup 2} device (825 mV Voc, 18.2 mA/cm{sup 2} Jsc, and 0.62 FF) deposited on a 100 cm{sup 2} substrate. On 8 cell, 64 cm{sup 2} submodules, the best result to date is 7.3% (5.9 V Voc, 130 mA Isc, and 0.61 FF). CdS, CdTe, and ZnTe films have been deposited onto 60 cm X 120 cm substrates - single cells produced from this material have exceeded 8% efficiency, 64 cm{sup 2} submodules have exceeded 5%. Module efficiency is limited by mechanical defects - mostly shunts - associated with processing after deposition of the semiconductor layer`s. Present best result is 1.4% total area efficiency. In anticipation of more advanced designs, CdTe films have also been deposited from apparatus employing elemental sources. This project is in an early stage and has produced only rudimentary results. A pro-active Safety, Health, Environmental and Disposal program has been developed. Results to date indicate that both employees and the environment have been protected against overexposure to hazards including toxic chemicals.
CCD drift-scan imaging lunar occultations: a feasible approach for sub-meter class telescopes
A CCD drift-scanning technique for lunar occultation (LO) observations is presented. While this approach has been addressed before by Sturmann (1994) for the case of large telescopes, the technical validity has never been discussed for sub-meter class telescopes. In contrast to Sturmann's scheme, the proposed technique places the CCD in the image plane of the telescope. This does not represent a problem in the case of small telescopes, where the practical angular resolution attainable by LO is not limited by aperture smoothing. Photon-generated charge is read out at millisecond rate on a column-per-column basis, as the diffraction pattern of the occulted star is being tracked. Two LO events (SAO 79031 and SAO 77911) were observed to demonstrate the feasibility of the method. Data analysis was carried out and no angular diameter the observed stars were resolved. We show, however, that the technique could be useful for close binary detections with small telescopes. A discussion of the limiting resolution and magnitude imposed by our instrumentation is carried out, showing that drift-scanning technique could be extended to 1-2m telescopes for stellar diameter determination purposes. Finally, we point out that the technical demands required by this technique can be easily met by most small professional observatories and advanced amateurs.
O. Fors; J. Nunez; A. Richichi
Development of large-area monolithically integrated Silicon-Film{trademark} photovoltaic modules. Annual subcontract report, 1 January 1993--31 December 1993
This report describes work performed under a program to develop Silicon-Film{trademark} Product III into a low-cost, stable solar cell for large-scale terrestrial power applications. The Product III structure is a thin polycrystalline layer of silicon on a durable, insulating, ceramic) substrate. The insulating substrate allows the silicon layer to be isolated and metallized to form a monolithically interconnected array of solar cells. High efficiency is achievable with the use of light trapping and a passivated back surface. The long-term goal for the product is a 1200-cm{sup {minus}2}, 18%-efficient solar module. This report discusses material quality improvements due to the use of new metallurgical barrier technologies. The barrier is essential in preventing impurity interaction between the silicon film and the low-cost substate. Also, a new filament-based fabric substate material was investigated. Efficiencies greater than 10% were achieved on 1.0-cm{sup 2} devices made on these substrates. We also demonstrated the monolithic fabrication sequence by the fabrication of a prototype array using the device processing sequences developed during Phase 11 of this program.
Rand, J.A.; Cotter, J.E.; Ingram, A.E.; Ruffins, T.R.; Thomas, C.J.; Hall, R.B.; Barnett, A.M. [AstroPower, Inc., Newark, DE (United States)
Development of large-area monolithically integrated Silicon-Film photovoltaic modules. Annual subcontract report, 16 November 1991--31 December 1992
This report describes work to develop Silicon-Film{trademark} Product III into a low-cost, stable solar cell for large-scale terrestrial power applications. The Product III structure is a thin (< 100-{mu}m) polycrystalline layer of silicon on a durable, insulating, ceramic substrate. The insulating substrate allows the silicon layer to be isolated and metallized to form a monolithically interconnected array of solar cells. High efficiency is achievable with the use of light trapping and a passivated back surface. The long-term goal for the product is a 1200-cm{sup 2}, 18%-efficient, monolithic array. The short-term objectives are to improve material quality and to fabricate 100 cm{sup 2} monolithically interconnected solar cell arrays. Low minority-carrier diffusion length in the silicon film and series resistance in the interconnected device structure are presently limiting device performance. Material quality is continually improving through reduced impurity contamination. Metallization schemes, such as a solder-dipped interconnection process, have been developed that will allow low-cost production processing and minimize R{sub s} effects. Test data for a nine-cell device (16 cm{sup 2}) indicated a V{sub oc} of 3.72 V. These first-reported monolithically interconnected multicrystalline silicon-on-ceramic devices show low shunt conductance (< 0.1 mA/cm{sup 2}) due to limited conduction through the ceramic and no process-related metallization shunts.
Rand, J.A.; Cotter, J.E.; Ingram, A.E.; Ruffins, T.R.; Shreve, K.P.; Hall, R.B.; Barnett, A.M. [AstroPower, Inc., Newark, DE (United States)
Scientific Objectives of Einstein Telescope
The advanced interferometer network will herald a new era in observational astronomy. There is a very strong science case to go beyond the advanced detector network and build detectors that operate in a frequency range from 1 Hz-10 kHz, with sensitivity a factor ten better in amplitude. Such detectors will be able to probe a range of topics in nuclear physics, astronomy, cosmology and fundamental physics, providing insights into many unsolved problems in these areas.
B. Sathyaprakash; M. Abernathy; F. Acernese; P. Ajith; B. Allen; P. Amaro-Seoane; N. Andersson; S. Aoudia; K. Arun; P. Astone; B. Krishnan; L. Barack; F. Barone; B. Barr; M. Barsuglia; M. Bassan; R. Bassiri; M. Beker; N. Beveridge; M. Bizouard; C. Bond; S. Bose; L. Bosi; S. Braccini; C. Bradaschia; M. Britzger; F. Brueckner; T. Bulik; H. J. Bulten; O. Burmeister; E. Calloni; P. Campsie; L. Carbone; G. Cella; E. Chalkley; E. Chassande-Mottin; S. Chelkowski; A. Chincarini; A. Di. Cintio; J. Clark; E. Coccia; C. N. Colacino; J. Colas; A. Colla; A. Corsi; A. Cumming; L. Cunningham; E. Cuoco; S. Danilishin; K. Danzmann; E. Daw; R. De. Salvo; W. Del. Pozzo; T. Dent; R. De. Rosa; L. Di. Fiore; M. Di. Paolo. Emilio; A. Di. Virgilio; A. Dietz; M. Doets; J. Dueck; M. Edwards; V. Fafone; S. Fairhurst; P. Falferi; M. Favata; V. Ferrari; F. Ferrini; F. Fidecaro; R. Flaminio; J. Franc; F. Frasconi; A. Freise; D. Friedrich; P. Fulda; J. Gair; M. Galimberti; G. Gemme; E. Genin; A. Gennai; A. Giazotto; K. Glampedakis; S. Gossan; R. Gouaty; C. Graef; W. Graham; M. Granata; H. Grote; G. Guidi; J. Hallam; G. Hammond; M. Hannam; J. Harms; K. Haughian; I. Hawke; D. Heinert; M. Hendry; I. Heng; E. Hennes; S. Hild; J. Hough; D. Huet; S. Husa; S. Huttner; B. Iyer; D. I. Jones; G. Jones; I. Kamaretsos; C. Kant Mishra; F. Kawazoe; F. Khalili; B. Kley; K. Kokeyama; K. Kokkotas; S. Kroker; R. Kumar; K. Kuroda; B. Lagrange; N. Lastzka; T. G. F. Li; M. Lorenzini; G. Losurdo; H. Lück; E. Majorana; V. Malvezzi; I. Mandel; V. Mandic; S. Marka; F. Marin; F. Marion; J. Marque; I. Martin; D. Mc. Leod; D. Mckechan; M. Mehmet; C. Michel; Y. Minenkov; N. Morgado; A. Morgia; S. Mosca; L. Moscatelli; B. Mours; H. Müller-Ebhardt; P. Murray; L. Naticchioni; R. Nawrodt; J. Nelson; R. O'. Shaughnessy; C. D. Ott; C. Palomba; A. Paoli; G. Parguez; A. Pasqualetti; R. Passaquieti; D. Passuello; M. Perciballi; F. Piergiovanni; L. Pinard; M. Pitkin; W. Plastino; M. Plissi; R. Poggiani; P. Popolizio; E. Porter; M. Prato; G. Prodi; M. Punturo; P. Puppo; D. Rabeling; I. Racz; P. Rapagnani; V. Re; J. Read; T. Regimbau; H. Rehbein; S. Reid; F. Ricci; F. Richard; C. Robinson; A. Rocchi; R. Romano; S. Rowan; A. Rüdiger; A. Samblowski; L. Santamaría; B. Sassolas; R. Schilling; P. Schmidt; R. Schnabel; B. Schutz; C. Schwarz; J. Scott; P. Seidel; A. M. Sintes; K. Somiya; C. F. Sopuerta; B. Sorazu; F. Speirits; L. Storchi; K. Strain; S. Strigin; P. Sutton; S. Tarabrin; B. Taylor; A. Thürin; K. Tokmakov; M. Tonelli; H. Tournefier; R. Vaccarone; H. Vahlbruch; J. F. J. van. den. Brand; C. Van. Den. Broeck; S. van. der. Putten; M. van. Veggel; A. Vecchio; J. Veitch; F. Vetrano; A. Vicere; S. Vyatchanin; P. Weßels; B. Willke; W. Winkler; G. Woan; A. Woodcraft; K. Yamamoto
Positioning system of the ANTARES Neutrino Telescope
Completed in May 2008, the ANTARES neutrino telescope is located 40 km off the coast of Toulon, at a depth of about 2500 m. The telescope consists of 12 detect or lines housing a total of 884 optical modules. Each line is anchored to the seabed and pulled taught by the buoyancy of the individual optical modules and a top buoy. Due to the fluid nature of the sea-water detecting medium and the flexible nature of the detector lines, the optical modules of the ANTARES telescope can suffer from deviations of up to several meters from the vertical and as such, real time positioning is needed. Real time positioning of the ANTARES telescope is achieved by a combination of an acoustic positioning system and a lattice of tiltmeters and compasses. These independent and complementary systems are used to compute a global fit to each individual detector line, allowing us to construct a 3 dimensional picture of the ANTARES neutrino telescope with an accuracy of less than 10 cm. In this paper we describe the positioning syst...
Brown, Anthony M
Development of large-area monolithically integrated silicon-film{trademark} photovoltaic modules. Final subcontract report, May 1, 1991--December 31, 1994
The objective of this program is to develop Silicon Film{trademark} Product III into a low-cost, stable solar cell for large-scale terrestrial power applications. The Product III structure is a thin (<100 {mu}m) polycrystalline layer of silicon on a durable, insulating, ceramic substrate. The insulating substrate allows the silicon layer to be isolated and metallized to form a monolithically interconnected array of solar cells. High efficiency is achieved by the use of light trapping and passivated surfaces. This project focused on the development of five key technologies associated with the monolithic sub-module device structure: (1) development of the film deposition and growth processes; (2) development of the low-cost ceramic substrate; (3) development of a metallurgical barrier technology; (4) development of sub-element solar cell processing techniques; and (5) development of sub-module (isolation and interconnection) processes. This report covers the development approaches and results relating to these technologies. Significant progress has been made in the development of all of the related technologies. This is evidenced by the fabrication of a working 12.0 cm{sup 2} prototype sub-module consisting of 7 elements and testing with an open circuit voltage of 3.9 volts, a short circuit current of 35.2 mA and a fill factor of 63% and an overall efficiency of 7.3%. Another significant result achieved is a 13.4% (NREL verified), 1.0 cm{sup 2} solar cell fabricated from material deposited and grown on a graphite cloth substrate. The significant technological hurdle of the program was and remains the low quality of the photovoltaic layer which is caused by contamination of the photovoltaic layer from the low-cost ceramic substrate by trace impurities found in the substrate precursor materials. The ceramic substrate and metallurgical barrier are being developed specifically to solve this problem.
Hall, R.B.; Rand, J.A.; Cotter, J.E. [AstroPower, Inc., Newark, DE (United States)
Discovery of Pulsations from the Pulsar J0205 6449 in SNR 3C 58 with the Fermi Gamma-Ray Space Telescope
We report the discovery of {gamma}-ray pulsations ({ge}0.1 GeV) from the young radio and X-ray pulsar PSR J0205 + 6449 located in the Galactic supernova remnant 3C 58. Data in the {gamma}-ray band were acquired by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope (formerly GLAST), while the radio rotational ephemeris used to fold {gamma}-rays was obtained using both the Green Bank Telescope and the Lovell telescope at Jodrell Bank. The light curve consists of two peaks separated by 0.49 {+-} 0.01 {+-} 0.01 cycles which are aligned with the X-ray peaks. The first {gamma}-ray peak trails the radio pulse by 0.08 {+-} 0.01 {+-} 0.01, while its amplitude decreases with increasing energy as for the other {gamma}-ray pulsars. Spectral analysis of the pulsed {gamma}-ray emission suggests a simple power law of index -2.1 {+-} 0.1 {+-} 0.2 with an exponential cutoff at 3.0{sub -0.7}{sup +1.1} {+-} 0.4 GeV. The first uncertainty is statistical and the second is systematic. The integral {gamma}-ray photon flux above 0.1 GeV is (13.7 {+-} 1.4 {+-} 3.0) x 10{sup -8} cm{sup -2} s{sup -1}, which implies for a distance of 3.2 kpc and assuming a broad fan-like beam a luminosity of 8.3 x 10{sup 34} erg s{sup -1} and an efficiency {eta} of 0.3%. Finally, we report a 95% upper limit on the flux of 1.7 x 10{sup -8} cm{sup -2} s{sup -1} for off-pulse emission from the object.
Abdo, Aous A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ajello, Marco; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Atwood, William B.; /UC, Santa Cruz; Axelsson, M.; /Stockholm U., OKC /Stockholm U.; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Barbiellini, Guido; /INFN, Trieste /Trieste U.; Bastieri, Denis; /INFN, Padua /Padua U.; Baughman, B.M.; /Ohio State U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bellazzini, Ronaldo; /INFN, Pisa; Berenji, Bijan; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Blandford, Roger D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bloom, Elliott D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, Anders W.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bouvier, A.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bregeon, J.; /INFN, Pisa; Brez, A.; /INFN, Pisa; Brigida, M.; /Bari U. /INFN, Bari /Ecole Polytechnique /Washington U., Seattle /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Columbia U. /IASF, Milan /IASF, Milan /DAPNIA, Saclay /INFN, Perugia /Perugia U. /NASA, Goddard /George Mason U. /Naval Research Lab, Wash., D.C. /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /LPCE, Orleans /Montpellier U. /Stockholm U., OKC /Royal Inst. Tech., Stockholm /Stockholm U. /Naval Research Lab, Wash., D.C. /INFN, Trieste /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /UC, Santa Cruz /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /CENBG, Gradignan /CENBG, Gradignan /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Manchester U. /Montpellier U. /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; /more authors..
32ND INTERNATIONAL COSMIC RAY CONFERENCE, BEIJING 2011 The HEAT Telescopes of the Pierre Auger Observatory
tanks on a 750 m grid close to the HEAT site the energy range of high quality hybrid air shower32ND INTERNATIONAL COSMIC RAY CONFERENCE, BEIJING 2011 The HEAT Telescopes of the Pierre Auger. A surface array of 1660 water Cherenkov detectors on a 1500 m triangular grid covers an area of 3000 km2
Hörandel, Jörg R.
The Atacama Cosmology Telescope was designed to measure small-scale anisotropies in the cosmic microwave background and detect galaxy clusters through the Sunyaev-Zel'dovich effect. The instrument is located on Cerro Toco in the Atacama Desert, at an altitude of 5190 m. A 6 m off-axis Gregorian telescope feeds a new type of cryogenic receiver, the Millimeter Bolometer Array Camera. The receiver features three 1000-element arrays of transition-edge sensor bolometers for observations at 148 GHz, 218 GHz, and 277 GHz. Each detector array is fed by free space millimeter-wave optics. Each frequency band has a field of view of approximately 22' x 26'. The telescope was commissioned in 2007 and has completed its third year of operations. We discuss the major components of the telescope, camera, and related systems, and summarize the instrument performance.
Swetz, D. S.; Devlin, M. J.; Dicker, S. R. [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Ade, P. A. R. [School of Physics and Astronomy, Cardiff University, The Parade, Cardiff, Wales CF24 3AA (United Kingdom); Amiri, M.; Battistelli, E. S.; Burger, B.; Halpern, M.; Hasselfield, M. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Appel, J. W.; Essinger-Hileman, T.; Fisher, R. P.; Fowler, J. W.; Hincks, A. D.; Jarosik, N. [Joseph Henry Laboratories of Physics, Jadwin Hall, Princeton University, Princeton, NJ 08544 (United States); Chervenak, J. [Code 553/665, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Doriese, W. B.; Hilton, G. C.; Irwin, K. D. [NIST Quantum Devices Group, 325 Broadway Mailcode 817.03, Boulder, CO 80305 (United States); Duenner, R. [Departamento de Astronomia y Astrofisica, Facultad de Fisica, PontificIa Universidad Catolica, Casilla 306, Santiago 22 (Chile)
Large Area Maskless Photopolymerization for Manufacturing of ...
Reactions in the Li2CO3:Al2O3:SiO2 System · Research on Firing Distortion Prediction and Correction Techniques for Ceramics Design · Sedimentation of ...
The Trigger System of the H.E.S.S. Telescope Array
H.E.S.S. -- The High Energy Stereoscopic System-- is a new system of large atmospheric Cherenkov telescopes for GeV/TeV Gamma-ray astronomy. This paper describes the trigger system of H.E.S.S. with emphasis on the multi-telescope array level trigger. The system trigger requires the simultaneous detection of air-showers by several telescopes at the hardware level. This requirement allows a suppression of background events which in turn leads to a lower system energy threshold for the detection of Gamma-rays. The implementation of the H.E.S.S. trigger system is presented along with data taken to characterise its performance.
S. Funk; G. Hermann; J. Hinton; D. Berge; K. Bernloehr; W. Hofmann; P. Nayman; F. Toussenel; P. Vincent
An Analog Trigger System for Atmospheric Cherenkov Telescopes
Arrays of Cherenkov telescopes typically use multi-level trigger schemes to keep the rate of random triggers from the night sky background low. At a first stage, individual telescopes produce a trigger signal from the pixel information in the telescope camera. The final event trigger is then formed by combining trigger signals from several telescopes. In this poster, we present a possible scheme for the Cherenkov Telescope Array telescope trigger, which is based on the analog pulse information of the pixels in a telescope camera. Advanced versions of all components of the system have been produced and working prototypes have been tested, showing a performance that meets the original specifications. Finally, issues related to integrating the trigger system in a telescope camera and in the whole array will be dealt with.
Barcelo, M; Bigas, O Blanch; Boix, J; Delgado, C; Herranz, D; Lopez-Coto, R; Martinez, G
The Nuclear Compton Telescope (NCT) is a balloon-borne Compton telescope designed for the study of astrophysical sources in the soft gamma-ray regime (200 keV-20 MeV). NCT's 10 high-purity germanium crossed-strip detectors measure the deposited energies and three-dimensional positions of gamma-ray interactions in the sensitive volume, and this information is used to restrict the initial photon to a circle on the sky using the Compton scatter technique. Thus NCT is able to perform spectroscopy, imaging, and polarization analysis on soft gamma-ray sources. NCT is one of the next generation of Compton telescopes-the so-called compact Compton telescopes (CCTs)-which can achieve effective areas comparable to the Imaging Compton Telescope's with an instrument that is a fraction of the size. The Crab Nebula was the primary target for the second flight of the NCT instrument, which occurred on 2009 May 17 and 18 in Fort Sumner, New Mexico. Analysis of 29.3 ks of data from the flight reveals an image of the Crab at a significance of 4{sigma}. This is the first reported detection of an astrophysical source by a CCT.
Bandstra, M. S.; Bellm, E. C.; Boggs, S. E.; Perez-Becker, D.; Zoglauer, A. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Chang, H.-K.; Chiu, J.-L.; Liang, J.-S. [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Chang, Y.-H.; Liu, Z.-K.; Hung, W.-C. [Department of Physics, National Central University, Taoyuan 32001, Taiwan (China); Huang, M.-H. A. [Department of Energy Engineering, National United University, Miaoli 36003, Taiwan (China); Chiang, S. J. [Department of Electrical Engineering, National United University, Miaoli 36003, Taiwan (China); Run, R.-S. [Department of Electronic Engineering, National United University, Miaoli 36003, Taiwan (China); Lin, C.-H. [Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Amman, M.; Luke, P. N. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Jean, P.; Von Ballmoos, P. [Centre d'Etude Spatiale des Rayonnements (CESR), 31028 Toulouse Cedex 4 (France); Wunderer, C. B., E-mail: firstname.lastname@example.com [Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, 22607 Hamburg (Germany)
Research on high-efficiency, large-area CuInSe{sub 2}-based thin-film modules. Final subcontract report, 16 August 1993--30 June 1995
This final subcontract report, describing work to fabricate a large-area, stable, 12.5% (aperture)-efficient encapsulated CuInSe{sub 2} (CIS) module by scalable, low-cost techniques on inexpensive substrates. Demonstrated encapsulated module efficiencies (encapsulated 12.8%-efficient mini-module on 68.9cm{sup 2} and an NREL-verified 12.7%-efficient unencapsulated circuit on 69 CM{sup 2} with a prismatic cover) are the highest reported mini-module demonstrated (and verified by NREL). This is the first thin-film module of its size to exceed the 10% efficiency level. SSI also supplied NREL with a 1-kW array of large-area ({approximately}3890 CM{sup 2}) approximately 30-W modules. The NREL-verified performance of this array is a significant step toward meeting the efficiency target of the USDOE Five-Year Plan goals of 8%--10%-efficient commercial thin-film, flat-plate modules. Long-term outdoor stability of CIS and CIS-based absorbers was demonstrated by testing at NREL. Excellent stability was demonstrated for 6 years of outdoor exposure. The stability of the 1-kW Siemens CIS array, installed and tested at NREL, was also demonstrated for an exposure of about 1 year. The foundations have been laid to meet the thin-film milestones of the DOE Five-Year Plan. Outdoor testing has demonstrated excellent intrinsic module stability. Future plans include scaling these results to larger areas and emphasizing the reduction of variation methodology to lay the foundation for demonstrating the potential of CIS as a future commercial product.
Tarrant, D.E.; Gay, R.R. [Siemens Solar Industries, Camarillo, CA (United States)
THE SPITZER SPACE TELESCOPE MISSION M. W. Werner,1
with a cryogenic telescope in space with the great imaging and spectroscopic power of modern detector arraysTHE SPITZER SPACE TELESCOPE MISSION M. W. Werner,1 T. L. Roellig,2 F. J. Low,3 G. H. Rieke,3 M2 Receivved 2004 March 26; accepted 2004 May 26 ABSTRACT The Spitzer Space Telescope, NASA's Great
Galis, Frietson
Ultra Violet Imaging Telescope (UVIT) on ASTROSAT
Ultra Violet Imaging Telescope on ASTROSAT Satellite mission is a suite of Far Ultra Violet (FUV 130 to 180 nm), Near Ultra Violet (NUV 200 to 300 nm) and Visible band (VIS 320 to 550nm) imagers. ASTROSAT is the first multi wavelength mission of INDIA. UVIT will image the selected regions of the sky simultaneously in three channels and observe young stars, galaxies, bright UV Sources. FOV in each of the 3 channels is about 28 arc-minute. Targeted angular resolution in the resulting UV images is better than 1.8 arc-second (better than 2.0 arc-second for the visible channel). Two identical co-aligned telescopes (T1, T2) of Ritchey-Chretien configuration (Primary mirror of 375 mm diameter) collect celestial radiation and feed to the detector system via a selectable filter on a filter wheel mechanism; gratings are available in filter wheels of FUV and NUV channels for slit-less low resolution spectroscopy. The detector system for each of the 3 channels is generically identical. One of the telescopes images in the...
Kumar, Amit; Hutchings, J; Kamath, P U; Kathiravan, S; Mahesh, P K; Murthy, J; S, Nagbhushana; Pati, A K; Rao, M N; Rao, N K; Sriram, S; Tandon, S N
A Cosmic Ray Telescope For Educational Purposes
Cosmic ray detectors are widely used, for educational purposes, in order to motivate students to the physics of elementary particles and astrophysics. Using a 'telescope' of scintillation counters, the directional characteristics, diurnal variation, correlation with solar activity, can be determined, and conclusions about the composition, origin and interaction of elementary particles with the magnetic field of earth can be inferred. A telescope was built from two rectangular scintillator panels with dimensions: 91.6x1.9x3.7 cm{sup 3}. The scintillators are placed on top of each other, separated by a fixed distance of 34.6 cm. They are supported by a wooden frame which can be rotated around a horizontal axis. Direction is determined by the coincidence of the signals of the two PMTs. Standard NIM modules are used for readout. This device is to be used in the undergraduate nuclear and particle physics laboratory. The design and construction of the telescope as well as some preliminary results are presented.
Voulgaris, G.; Kazanas, S.; Chamilothoris, I. [Department of Physics, National and Kapodistrian University of Athens (Greece)
Silicon-on ceramic process. Silicon sheet growth and device development for the large-area silicon sheet and cell development tasks of the low-cost solar array project. Quarterly report No. 12, April 2, 1979-June 29, 1979
The objective of this research program is to investigate the technical and economic feasibility of producing solar-cell-quality sheet silicon. We plan to do this by coating one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon from the melt. During the quarter, significant progress was demonstrated in several areas: (1) a 10-cm/sup 2/ cell having 9.9 percent conversion efficiency (AM1, AR) was fabricated; (2) the Honeywall-sponsored SCIM coating development succeeded in producing a 225-cm/sup 2/ layer of sheet silicon (18 inches x 2 inches); and (3) 100 ..mu..m-thick coatings at pull speed of 0.15 cm/sec wer$obta9ned, although apoproximately 50 percent of the layer exhibited dendritic growth. Other results and accomplishments during the quarter are reported in detail. (WHK)
Chapman, P.W.; Zook, J.D.; Heaps, J.D.; Grung, B.L.; Koepke, B.; Schuldt, S.B.
Development of methods of producing large areas of silicon sheet by the slicing of silicon ingots using inside-diameter (I. D. ) saws. Final report, May 1979-April 1980
I.D. wafering equipment, blades and processes were used to develop methods for producing large areas of silicon sheet. Modifications to a 16 inch STC automated saw included programmable feed system; crystal rotating system; and STC dyna-track blade monitoring and control system. By controlling the plating operation and by grinding of the cutting edge, we were able to produce 16 inch I.D. blades with a cutting edge thickness of .22 mm. Crystal rotation mechanism was used to slice 100 mm diameter crystals with a 16 inch blade down to a thickness of .20 mm. Cutting rates with crystal rotation were generally slower than with standard plunge I.D. slicing techniques. Using programmed feeds and programmed rotation, maximum cutting rates were from 0.3 to 1.0 inches per minute.
Aharonyan, P.
Silicon-on ceramic process. Silicon sheet growth and device developmentt for the Large-Area Silicon Sheet Task of the Low-Cost Solar Array Project. Quarterly report No. 13, October 1-December 31, 1979
Research on the technical and economic feasibility of producing solar-cell-quality sheet silicon by coating inexpensive ceramic substrates with a thin layer of polycrystalline silicon is reported. The coating methods to be developed are directed toward a minimum-cost process for producing solar cells with a terrestrial conversion efficiency of 11 percent or greater. By applying a graphite coating to one face of a ceramic substrate, molten silicon can be caused to wet only that graphite-coated face and produce uniform thin layers of large-grain polycrystalline silicon; thus, only a minimal quantity of silicon is consumed. A variety of ceramic materials have been dip coated with silicon. The investigation has shown that mullite substrates containing an excess of SiO/sub 2/ best match the thermal expansion coefficient of silicon and hence produce the best SOC layers. With such substrates, smooth and uniform silicon layers 25 cm/sup 2/ in area have been achieved with single-crystal grains as large as 4 mm in width and several cm in length. Crystal length is limited by the length of the substrate. The thickness of the coating and the size of the crystalline grains are controlled by the temperature of the melt and the rate at which the substrate is withdrawn from the melt. The solar-cell potential of this SOC sheet silicon is promising. To date, solar cells with areas from 1 to 10 cm/sup 2/ have been fabricated from material with an as-grown surface. Conversion efficiencies of about 10 percent with antireflection (AR) coating have been achieved. Such cells typically have open-circuit voltage and short-circuit current densities of 0.55V and 23 mA/cm/sup 2/, respectively.
Chapman, P W; Zook, J D; Grung, B L; McHenry, K; Schuldt, S B
Silicon-on ceramic process: silicon sheet growth and device development for the large-area silicon sheet task of the Low-Cost Solar Array Project. Quarterly report NO. 15, April 1, 1980-June 30, 1980
The objective of this research is to investigate the technical feasibility of producing solar-cell-quality sheet silicon which could meet the DOE cost goals. The Honeywell approach is to coat one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon from the melt. Results and accomplishments which occurred during the quarter can be summarized as follows: (1) two major problems associated with SCIM-coating wide (10-cm) substrates were identified and solved; (2) the longitudinal temperature profile in SCIM-II has been improved to prevent substrate warping, buckling, and cracking; (3) the transverse temperature profile in SCIM II has been improved to produce more uniform coatings; (4) a strategy to eliminate effects of thermal stress has been developed; (5) the best SOC cell has a total-area conversion efficiency of 10.5% (AM1, AR), for a cell area of 5 cm/sup 2/; (6) a number of experiments are being investigated for improving cell efficiency; (7) for the slow-cooldown experiment, the average efficiency of 29 AR-coated cells was 9.9%, with a standard deviation of 0.3%; (8) encouraging results were obtained on SOC material that had been treated in a hydrogen plasma at Sandia; and (9) thermal modeling has proven to be beneficial in designing modifications of SCIM II.
Whitehead, A B; Zook, J D; Grung, B L; McHenry, K; Schuldt, S B; Chapman, P W
The dual-mirror Small Size Telescope for the Cherenkov Telescope Array
In this paper, the development of the dual mirror Small Size Telescopes (SST) for the Cherenkov Telescope Array (CTA) is reviewed. Up to 70 SST, with a primary mirror diameter of 4 m, will be produced and installed at the CTA southern site. These will allow investigation of the gamma-ray sky at the highest energies accessible to CTA, in the range from about 1 TeV to 300 TeV. The telescope presented in this contribution is characterized by two major innovations: the use of a dual mirror Schwarzschild-Couder configuration and of an innovative camera using as sensors either multi-anode photomultipliers (MAPM) or silicon photomultipliers (SiPM). The reduced plate-scale of the telescope, achieved with the dual-mirror optics, allows the camera to be compact (40 cm in diameter), and low-cost. The camera, which has about 2000 pixels of size 6x6 mm^2, covers a field of view of 10{\\deg}. The dual mirror telescopes and their cameras are being developed by three consortia, ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana, Italy/INAF), GATE (Gamma-ray Telescope Elements, France/Paris Observ.) and CHEC (Compact High Energy Camera, universities in UK, US and Japan) which are merging their efforts in order to finalize an end-to-end design that will be constructed for CTA. A number of prototype structures and cameras are being developed in order to investigate various alternative designs. In this contribution, these designs are presented, along with the technological solutions under study.
G. Pareschi; G. Agnetta; L. A. Antonelli; D. Bastieri; G. Bellassai; M. Belluso; C. Bigongiari; S. Billotta; B. Biondo; G. Bonanno; G. Bonnoli; P. Bruno; A. Bulgarelli; R. Canestrari; M. Capalbi; P. Caraveo; A. Carosi; E. Cascone; O. Catalano; M. Cereda; P. Conconi; V. Conforti; G. Cusumano; V. De Caprio; A. De Luca; A. Di Paola; F. Di Pierro; D. Fantinel; M. Fiorini; D. Fugazza; D. Gardiol; M. Ghigo; F. Gianotti; S. Giarrusso; E. Giro; A. Grillo; D. Impiombato; S. Incorvaia; A. La Barbera; N. La Palombara; V. La Parola; G. La Rosa; L. Lessio; G. Leto; S. Lombardi; F. Lucarelli; M. C. Maccarone; G. Malaguti; G. Malaspina; V. Mangano; D. Marano; E. Martinetti; R. Millul; T. Mineo; A. MistŇ; C. Morello; G. Morlino; M. R. Panzera; G. Rodeghiero; P. Romano; F. Russo; B. Sacco; N. Sartore; J. Schwarz; A. Segreto; G. Sironi; G. Sottile; A. Stamerra; E. Strazzeri; L. Stringhetti; G. Tagliaferri; V. Testa; M. C. Timpanaro; G. Toso; G. Tosti; M. Trifoglio; P. Vallania; S. Vercellone; V. Zitelli; For The Astri Collaboration; J. P. Amans; C. Boisson; C. Costille; J. L. Dournaux; D. Dumas; G. Fasola; O. Hervet; J. M. Huet; P. Laporte; C. Rulten; H. Sol; A. Zech; For The Gate Collaboration; R. White; J. Hinton; D. Ross; J. Sykes; S. Ohm; J. Schmoll; P. Chadwick; T. Greenshaw; M. Daniel; G. Cotter; G. S. Varner; S. Funk; J. Vandenbroucke; L. Sapozhnikov; J. Buckley; P. Moore; D. Williams; S. Markoff; J. Vink; D. Berge; N. Hidaka; A. Okumura; H. Tajima; For The Chec Collaboration; For The Cta Consortium
Software Spectral Correlator for the 44-Element Ooty Radio Telescope
A Spectral Correlator is the main component of the real time signal processing for a Radio Telescope array. The correlation of signals received at each element with every other element of the array is a classic case of an application requiring a complete graph connectivity between its data sources, as well as a very large number of simple operations to carry out the correlation. Datarates can be extremely large in order to achieve high sensitivities required for the detection of weak celestial signals. Hence, correlators are prime targets for HPC implementations. In this paper, we present the design and implementation of a massively parallel software spectral Correlator for a 44 element array. The correlator handles ~735 MB/s of incoming data from the 44 spatially distributed sources, and concurrently sustains a computational load of ~100 Gflops. We first describe how we partition the large incoming data stream into grouped datasets suited for transport over high speed serial networks, as well as ideal for pr...
Prasad, Peeyush
Meet with Large Businesses
Meet with Large Businesses Meet with Large Businesses and learn about upcoming acquisitions! * Federal Energy Management Program (FEMP) * National Renewable Energy Laboratory (NREL) * Small Business Administration (SBA) * U.S. Department of Energy / Energy, Efficiency, and Renewable Energy (EERE) * U.S. Department of Energy / Golden Field Office (GFO) * Western Area Power Administration (WAPA) * Colorado Procurement Technical Assistance Center (PTAC)
Silicon on ceramic process. Silicon sheet growth development for the Large-Area Silicon Sheet Task of the Low-Cost Silicon Solar Array Project. Annual report No. 2, September 17, 1976--September 19, 1977
The objective of this research program is to investigate the technical and economic feasibility of producing solar-cell-quality sheet silicon by coating one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon from the melt. In the past year significant progress was made in all areas of the program. The physical and chemical properties of the standard mullite refractory used for the majority of the coating runs (McDanel MV20 and Coors S1SI) have been characterized. A number of experimental compositions have been identified and procured from Coors. Characterization of the standard compositions revealed that the thermal expansion of mullite depends on both relative amounts of glass phase and on the impurity level in the glass. Since the thermal expansion in mullite exceeds that of silicon, the silicon coating should be in a state of compression. This was confirmed by x-ray measurements. After modifying and cleaning the dip-coating facility, silicon on ceramic (SOC) solar cells were fabricated which demonstrate that the SOC process can produce silicon of solar cell quality. SOC cells having 1 cm/sup 2/ active areas demonstrated measured conversion efficiencies as high as 7.2 percent. Typical open-ciruit voltages (V/sub oc/) and short-circuit current densities (J/sub sc/) were 0.51 volt and 20 mA/cm/sup 2/, respectively. Since the active surface of these solar cells is a highly reflective ''as-grown'' surface, one can expect improvement in J/sub sc/ after an anti-reflection (AR) coating is applied. Results of an economic analysis of the SOC process are presented.
Zook, J.D.; Heaps, J.D.; Maciolek, R.B.; Koepke, B.; Butter, C.D.; Schuldt, S.B.
Detection and Imaging of the Crab Nebula with the Nuclear Compton Telescope
The Nuclear Compton Telescope (NCT) is a balloon-borne Compton telescope designed for the study of astrophysical sources in the soft gamma-ray regime (200 keV--20 MeV). NCT's ten high-purity germanium crossed-strip detectors measure the deposited energies and three-dimensional positions of gamma-ray interactions in the sensitive volume, and this information is used to restrict the initial photon to a circle on the sky using the Compton scatter technique. Thus NCT is able to perform spectroscopy, imaging, and polarization analysis on soft gamma-ray sources. NCT is one of the next generation of Compton telescopes --- so-called compact Compton telescopes (CCTs) --- which can achieve effective areas comparable to COMPTEL's with an instrument that is a fraction of the size. The Crab Nebula was the primary target for the second flight of the NCT instrument, which occurred on 17--18 May 2009 in Fort Sumner, New Mexico. Analysis of 29.3 ks of data from the flight reveals an image of the Crab at a significance of 4-si...
Bandstra, M S; Boggs, S E; Perez-Becker, D; Zoglauer, A; Chang, H -K; Chiu, J -L; Liang, J -S; Chang, Y -H; Liu, Z -K; Hung, W -C; Huang, M -H A; Chiang, S J; Run, R -S; Lin, C -H; Amman, M; Luke, P N; Jean, P; von Ballmoos, P; Wunderer, C B
The ROTSE-IIIa Telescope System
We report on the current operating status of the ROTSE-IIIa telescope, currently undergoing testing at Los Alamos National Laboratories in New Mexico. It will be shipped to Siding Spring Observatory, Australia, in first quarter 2002. ROTSE-IIIa has been in automated observing mode since early October, 2001, after completing several weeks of calibration and check-out observations. Calibrated lists of objects in ROTSE-IIIa sky patrol data are produced routinely in an automated pipeline, and we are currently automating analysis procedures to compile these lists, eliminate false detections, and automatically identify transient and variable objects. The manual application of these procedures has already led to the detection of a nova that rose over six magnitudes in two days to a maximum detected brightness of m_R~13.9 and then faded two magnitudes in two weeks. We also readily identify variable stars, includings those suspected to be variables from the Sloan Digital Sky Survey. We report on our system to allow public monitoring of the telescope operational status in real time over the WWW.
D. A. Smith; C. Akerlof; M. C. B. Ashley; D. Casperson; G. Gisler; R. Kehoe; S. Marshall; K. McGowan; T. McKay; M. A. Phillips; E. Rykoff; W. T. Vestrand; P. Wozniak; J. Wren
Imaging Atmospheric Cerenkov Telescopes: Techniques and Results
The hunt for cosmic TeV particle accelerators is prospering through Imaging Atmospheric Cerenkov Telescopes. We face challenges such as low light levels and MHz trigger rates, and the need to distinguish between particle air showers stemming from primary gamma rays and those due to the hadronic cosmic ray background. Our test beam is provided by the Crab Nebula, a steady accelerator of particles to energies beyond 20 TeV. Highly variable gamma-ray emission, coincident with flares at longer wavelengths, is revealing the particle acceleration mechanisms at work in the relativistic jets of Active Galaxies. These 200 GeV to 20 TeV photons propagating over cosmological distances allow us to place a limit on the infra-red background linked to galaxy formation and, some speculate, to the decay of massive relic neutrinos. Gamma rays produced in neutralino annihilation or the evaporation of primordial black holes may also be detectable. These phenomena and a zoo of astrophysical objects will be the targets of the next generation multi-national telescope facilities.
S. M. Bradbury
A Short and Personal History of the Spitzer Space Telescope
The Spitzer Space Telescope, born as the Shuttle Infrared Telescope Facility (SIRTF) and later the Space Infrared Telescope Facility (still SIRTF), was under discussion and development within NASA and the scientific community for more than 30 years prior to its launch in 2003. This brief history chronicles a few of the highlights and the lowlights of those 30 years from the authors personal perspective. A much more comprehensive history of SIRTF/Spitzer has been written by George Rieke (2006).
Michael Werner
Status of the second phase of the MAGIC telescope
The MAGIC 17m diameter Cherenkov telescope will be upgraded with a second telescope with advanced photon detectors and ultra fast readout within the year 2007. The sensitivity of MAGIC-II, the two telescope system, will be improved by a factor of 2. In addition the energy threshold will be reduced and the energy and angular resolution will be improved. The design, status and expected performance of MAGIC-II is presented here.
Florian Goebel; for the MAGIC collaboration
Dip-coating process. Silicon sheet growth development for the large-area silicon sheet task of the low-cost silicon solar array project. Quarterly report No. 7
The objective of this research program is to investigate the technical and economic feasibility of producing solar-cell-quality sheet silicon by coating one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon from the melt. During the past quarter, significant progress was demonstrated in several areas. Seeded growth of silicon-on-ceramic (SOC) with an EFG ribbon seed was demonstrated. Different types of mullite received from Coors were successfully coated with silicon. A new method of deriving minority carrier diffusion length, L/sub n/, from spectral response measurements was evaluated. ECOMOD cost projections were found to be in good agreement with the interim SAMIS method proposed by JPL. On the less positive side, there was a decrease in cell performance which is believed to be due to an unidentified source of impurities. Also, operation of the new coating system fell behind schedule but is expected to improve in the coming quarter, since construction has now been completed.
Optimal Networks of Future Gravitational-Wave Telescopes
We aim to find the optimal site locations for a hypothetical network of 1-3 triangular gravitational-wave telescopes. We define the following N-telescope figures of merit and construct three corresponding metrics: (a) capability of reconstructing the signal polarization; (b) accuracy in source localization; and (c) accuracy in reconstructing the parameters of a standard binary source. We also define a combined metric that takes into account the three figures of merit with practically equal weight. After constructing a geomap of possible telescope sites, we give the optimal 2-telescope networks for the four figures of merit separately in example cases where the location of the first telescope has been predetermined. We found that the optimal site locations for a second telescope based on the combined metric form a +/-7 deg annulus at an angular distance of ~130 deg from the location of the first telescope. Based on this result we conclude that placing the first telescope to Australia provides the most options ...
Raffai, Peter; Heng, Ik Siong; Kelecsenyi, Nandor; Logue, Josh; Marka, Zsuzsa; Marka, Szabolcs
Dip coating process. Silicon sheet growth development for the large-area silicon sheet task of the low-cost silicon solar array project. Quarterly report No. 6, March 22, 1977--June 24, 1977
The objective of this research program is to investigate the technical and economic feasibility of producing solar-cell-quality sheet silicon by coating one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon from the melt. Significant progress was made in silicon on ceramic (SOC) solar cell performance. SOC cells having 1 cm/sup 2/ active areas demonstrated measured conversion efficiencies as high as 7.2 percent. Typical open circuit voltages (V/sub oc/) and short circuit current densities (J/sub sc/) were 0.51 volt and 20 mA/cm/sup 2/ respectively. Since the active surface of these solar cells is a highly reflective ''as-grown'' surface, one can expect improvement in J/sub sc/ after an anti-reflection (AR) coating is applied. It is significant that single-crystal comparison cells, also measured without benefit of an AR coating, had efficiencies in the 8.5 percent range with typical V/sub oc/'s and J/sub sc/'s of 0.54 volt and 23 mA/cm/sup 2/, respectively. Therefore, improvement in cell design and junction diffusion techniques should increase the efficiency of both the SOC and single-crystal cells. During this quarter the dip coating facility was inadvertently contaminated, but has since been restored to a purity level exceeding its original state. With this facility, silicon coatings were grown with a single-crystal seed attached to the substrate. Single-crystal silicon was not forthcoming, but the results were nonetheless encouraging. Several of the carbon coating types tried appear promising, including one which has high purity and can be applied uniformly by swab or airbrush.
The Allen Telescope Array Search for Electrostatic Discharges on Mars
The Allen Telescope Array was used to monitor Mars between 9 March and 2 June 2010, over a total of approximately 30 hours, for radio emission indicative of electrostatic discharge. The search was motivated by the report from Ruf et al. (2009) of the detection of non-thermal microwave radiation from Mars characterized by peaks in the power spectrum of the kurtosis, or kurtstrum, at 10 Hz, coinciding with a large dust storm event on 8 June 2006. For these observations, we developed a wideband signal processor at the Center for Astronomy Signal Processing and Electronics Research (CASPER). This 1024-channel spectrometer calculates the accumulated power and power-squared, from which the spectral kurtosis is calculated post-observation. Variations in the kurtosis are indicative of non-Gaussianity in the signal, which can be used to detect variable cosmic signals as well as radio frequency interference (RFI). During the three month period of observations, dust activity occurred on Mars in the form of small-scale d...
Anderson, Marin M; Barott, William C; Bower, Geoffrey C; Delory, Gregory T; de Pater, Imke; Werthimer, Dan
Real-time condition assessment of RAPTOR telescope systems
The RAPid Telescopes for Optical Response (RAPTOR) observatory network consists of several robotic astronomical telescopes primarily designed to search for astrophysical transients called a gamma-ray bursts (GRBs). Although intrinsically bright, GRBs are difficult to detect because of their short duration. Typically, they are first observed by satellites that then relay the coordinates of the GRB to a ground station which, in turn, distributes the coordinates over the internet so that ground based observers can perform follow-up observations. Typically the ground based observations begin after the GRB has ended and only residual emiSSion (the 'afterglow') is left. However, if the satellite relays the GRB coordinates quickly enough, a 'fast' robotic telescope on the ground may be able to catch the GRB in progress. The RAPTOR telescope system is one of only a few in the world to have accomplished this feat. In order to achieve these results, the RAPTOR telescopes must operate autonomously at a high duty-cycle and in peak operating condition. Currently the telescopes are maintained in an ad hoc manner, often in a run-to-failure mode. The RAPTOR project could benefit greatly from a structural health monitoring (SHM) system, especially as more complex units are added to the suite of telescopes. This paper will summarize preliminary results from an SHM study performed on one of the RAPTOR telescopes. Damage scenarios that are of concern and that have been previously observed are first summarized. Then a specific study of damage to the telescope drive mechanism is presented where the data acquisition system is first described. Next, damage detection algorithms are developed with LANL's new publically available software SHMTools and the results of this process are discussed in detail. The paper will conclude with a summary of future planned refinemenls of the RAPTOR SHM system.
Stull, Chris [Los Alamos National Laboratory; Taylor, Stuart [Los Alamos National Laboratory; Wren, James [Los Alamos National Laboratory; Farrar, Charles [Los Alamos National Laboratory; Park, Gyuhae [Los Alamos National Laboratory
A retrospective of the GREGOR solar telescope in scientific literature
In this review, we look back upon the literature, which had the GREGOR solar telescope project as its subject including science cases, telescope subsystems, and post-focus instruments. The articles date back to the year 2000, when the initial concepts for a new solar telescope on Tenerife were first presented at scientific meetings. This comprehensive bibliography contains literature until the year 2012, i.e., the final stages of commissioning and science verification. Taking stock of the various publications in peer-reviewed journals and conference proceedings also provides the "historical" context for the reference articles in this special issue of Astronomische Nachrichten/Astronomical Notes.
Denker, C; Feller, A; Arlt, K; Balthasar, H; Bauer, S -M; González, N Bello; Berkefeld, T; Caligari, P; Collados, M; Fischer, A; Granzer, T; Hahn, T; Halbgewachs, C; Heidecke, F; Hofmann, A; Kentischer, T; Klva?a, M; Kneer, F; Lagg, A; Nicklas, H; Popow, E; Puschmann, K G; Rendtel, J; Schmidt, D; Schmidt, W; Sobotka, M; Solanki, S K; Soltau, D; Staude, J; Strassmeier, K G; Volkmer, R; Waldmann, T; Wiehr, E; Wittmann, A D; Woche, M
The Solar Optical Telescope for the Hinode Mission: An Overview
The Solar Optical Telescope (SOT) aboard the Hinode satellite (formerly called Solar-B) consists of the Optical Telescope Assembly (OTA) and the Focal Plane Package (FPP). The OTA is a 50 cm diffraction-limited Gregorian telescope, and the FPP includes the narrow-band (NFI) and wide-band (BFI) filtergraphs, plus the Stokes spectro-polarimeter (SP). SOT provides unprecedented high resolution photometric and vector magnetic images of the photosphere and chromosphere with a very stable point spread function, and is equipped with an image stabilization system that reduces the error to less than 0.01 arcsec rms. Together with the other two instruments on Hinode (the X-Ray Telescope (XRT) and EUV Imaging Spectrometer (EIS)), SOT is poised to address many fundamental questions about solar magneto-hydrodynamics. Note that this is an overview, and the details of the instrument are presented in a series of companion papers.
S. Tsuneta
Hubble space telescope; A new window opens on the universe
This paper reports on the Hubble space telescope. The telescope is expected to help answer key questions in astronomy, astrophysics, and cosmology, such as how stars and galaxies form and evolve; the size and age of the universe; the nature of quasars, black holes, and other exotic objects; the characteristics of planets in our solar system; and evidence for existence of planets orbiting other stars.
Seltzer, R.J. (C and EN, Washington, DC (US))
The Sloan Digital Sky Survey Monitor Telescope Pipeline
The photometric calibration of the Sloan Digital Sky Survey (SDSS) is a multi-step process which involves data from three different telescopes: the 1.0-m telescope at the US Naval Observatory (USNO), Flagstaff Station, Arizona (which was used to establish the SDSS standard star network); the SDSS 0.5-m Photometric Telescope (PT) at the Apache Point Observatory (APO), New Mexico (which calculates nightly extinctions and calibrates secondary patch transfer fields); and the SDSS 2.5-m telescope at APO (which obtains the imaging data for the SDSS proper). In this paper, we describe the Monitor Telescope Pipeline, MTPIPE, the software pipeline used in processing the data from the single-CCD telescopes used in the photometric calibration of the SDSS (i.e., the USNO 1.0-m and the PT). We also describe transformation equations that convert photometry on the USNO-1.0m u'g'r'i'z' system to photometry the SDSS 2.5m ugriz system and the results of various validation tests of the MTPIPE software. Further, we discuss the semi-automated PT factory, which runs MTPIPE in the day-to-day standard SDSS operations at Fermilab. Finally, we discuss the use of MTPIPE in current SDSS-related projects, including the Southern u'g'r'i'z' Standard Star project, the u'g'r'i'z' Open Star Clusters project, and the SDSS extension (SDSS-II).
D. L. Tucker; S. Kent; M. W. Richmond; J. Annis; J. A. Smith; S. S. Allam; C. T. Rodgers; J. L. Stute; J. K. Adelman-McCarthy; J. Brinkmann; M. Doi; D. Finkbeiner; M. Fukugita; J. Goldston; B. Greenway; J. E. Gunn; J. S. Hendry; D. W. Hogg; S. -I. Ichikawa; Z. Ivezic; G. R. Knapp; H. Lampeitl; B. C. Lee; H. Lin; T. A. McKay; A. Merrelli; J. A. Munn; E. H. Neilsen, Jr.; H. J. Newberg; G. T. Richards; D. J. Schlegel; C. Stoughton; A. Uomoto; B. Yanny
No. 16 ISSN 10278389 March 2012 The Southern African Large Telescope (Courtesy: S.B. Potter)
in an environment of an actual political incident, the one known as the SÂ300 crisis, which occurred between January the environment described above, we first simulated the S-300 incident using the CNFCM model of Figure 1 evidence referring to the period under study. The incident, however, does not appear to affect
Glass, Ian S.
The Search for Dark Matter with the Fermi Gamma Ray Space Telescope
The Fermi Gamma-Ray Space Telescope has been scanning the gamma ray sky since it was launched by NASA in June 2008 and has a mission lifetime goal of 10 years. Largely due to our particle physics heritage, one of the main physics topics being studied by the Fermi LAT Collaboration is the search for dark matter via indirect detection. My talk will review the progress of these studies, something on how the LAT detector enables them, and expectations for the future. I will discuss both gamma-ray and (electron + positron) searches for dark matter, and some resulting theoretical implications.
Bloom, Elliott (SLAC)
Triggering of Imaging Air Cherenkov Telescopes: PMT trigger rates due to night-sky photons
Imaging air Cherenkov telescopes are usually triggered on a coincidence of two or sometimes more pixels, with discriminator thresholds in excess of 20 photoelectrons applied for each pixel. These thresholds required to suppress night-sky background are significantly higher than expected on the basis of a Poisson distribution in the number of night-sky photoelectrons generated during the characteristic signal integration time. We studied noise trigger rates under controlled conditions using an artificial background light source. Large tails in the PMT amplitude response to single photoelectrons are identified as a dominant contribution to noise triggers. The rate of such events is very sensitive to PMT operating parameters.
G. Hermann; C. Köhler; T. Kutter; W. Hofmann
Module process optimization and device efficiency improvement for stable, low-cost, large-area, cadmium telluride-based photovoltaic module production. Annual subcontract report, 1 July 1990--31 December 1991
Albright, S.P.; Ackerman, B.; Chamberlin, R.R.; Jordan, J.F. [Photon Energy, Inc., El Paso, TX (United States)
Module process optimization and device efficiency improvement for stable, low-cost, large-area, cadmium telluride-based photovoltaic module production. Final subcontract report, 1 July 1990--30 April 1994
This report describes work performed under a three-phase subcontract. The objectives of the program include (1) achievement of active-area efficiencies of greater than 14% on small cells; (2) achievement of aperture-area efficiencies of greater than 13% on 0.09-m{sup 2} (1 ft{sup 2}) modules; (3) achievement of aperture-area efficiencies of greater than 12.5% on 0.37-m{sup 2} (4 ft{sup 2}) modules; and achievement of greater than 20-year module life (based on life testing extrapolations) with no greater than 10% efficiency degradation. The results obtained and described herein include the following: (1) efficiencies of 12.7% were achieved on small-area devices; (2) 0.09-m{sup 2} (1 ft{sup 2}) modules achieved greater than 8% aperture-area efficiency, but work for further efficiency improvement was redirected toward the 0.37-M{sup 2} (4 if) modules; (3) 0.37-m{sup 2} (4 ft{sup 2}) modules achieved 26.5-W output, which calculates to 8.0% aperture-area efficiency; (4) consistent prototype production was focused on and substantially achieved within Phase 2; (5) life testing at the National Renewable Energy Laboratory showed no inherent stability problems with the CdTe technology, and the accuracy of module measurement was satisfactorily resolved; and (6) a ``cradle-to-cradle`` recycling program was begun based upon the philosophy that the establishment of such mechanisms will be required to ensure maximum recapture and recycling of all manufacturing waste materials and/or modules returned from the field.
Albright, S.P.; Johnson, S.X. [Golden Photon, Inc., CO (United States)
Research Areas
Areas Areas Research Areas Print Scientists from a wide variety of fields come to the ALS to perform experiements. Listed below are some of the most common research areas covered by ALS beamlines. Below each heading are a few examples of the specific types of topics included in that category. Click on a heading to learn more about that research area at the ALS. Energy Science Photovoltaics, photosynthesis, biofuels, energy storage, combustion, catalysis, carbon capture/sequestration. Bioscience General biology, structural biology. Materials/Condensed Matter Correlated materials, nanomaterials, magnetism, polymers, semiconductors, water, advanced materials. Physics Atomic, molecular, and optical (AMO) physics; accelerator physics. Chemistry Surfaces/interfaces, catalysts, chemical dynamics (gas-phase chemistry), crystallography, physical chemistry.
Heat exchanger-ingot casting/slicing process. Silicon sheet growth development for the Large Area Silicon Sheet Task of the Low Cost Silicon Solar Array Project. Second quarterly progress report, January 1, 1976--March 31, 1976
The object of this program is to demonstrate that large single-crystal ingots can be economically cast by the Heat Exchanger Method (HEM) and economically sliced into thin sheets with a multi-wafer slicer. An experimental program is described which is designed to demonstrate the potential and isolate the limiting parameters for crystal casting and slicing with the Heat Exchanger Method (HEM) and the multi-wafer slicer. (WDM)
Schmid, F.
Research Areas Print Research Areas Print Scientists from a wide variety of fields come to the ALS to perform experiements. Listed below are some of the most common research areas covered by ALS beamlines. Below each heading are a few examples of the specific types of topics included in that category. Click on a heading to learn more about that research area at the ALS. Energy Science Photovoltaics, photosynthesis, biofuels, energy storage, combustion, catalysis, carbon capture/sequestration. Bioscience General biology, structural biology. Materials/Condensed Matter Correlated materials, nanomaterials, magnetism, polymers, semiconductors, water, advanced materials. Physics Atomic, molecular, and optical (AMO) physics; accelerator physics. Chemistry Surfaces/interfaces, catalysts, chemical dynamics (gas-phase chemistry), crystallography, physical chemistry.
Heat exchanger-ingot casting/slicing process. Silicon sheet growth development for the large area silicon sheet task of the low cost Silicon Solar Array Project. Third quarterly progress report, April 1, 1976--June 18, 1976
The object of this program is to demonstrate that large single-crystal ingots, 6-inch diameter by 4 inches tall, can be economically cast by the Heat Exchanger Method (HEM) and economically sliced into thin sheets, 0.008-inches thick, with a multi-wafer slicer. The thrust of the experimental work during this quarter was to establish the proper seed meltback and to nucleate single-crystal growth off the seed. Slicing tests were begun on the multi-blade wafering machine, using a newly fabricated sensitive feed mechanism and associated components. (WDM)
Schmid, F.; Reynolds, B.
Hinode/Solar Optical Telescope (SOT) observations reveal two new dynamic modes in quiescent solar prominences: large-scale (20-50 Mm) 'arches' or 'bubbles' that 'inflate' from below into prominences, and smaller-scale (2-6 Mm) dark turbulent upflows. These novel dynamics are related in that they are always dark in visible-light spectral bands, they rise through the bright prominence emission with approximately constant speeds, and the small-scale upflows are sometimes observed to emanate from the top of the larger bubbles. Here we present detailed kinematic measurements of the small-scale turbulent upflows seen in several prominences in the SOT database. The dark upflows typically initiate vertically from 5 to 10 Mm wide dark cavities between the bottom of the prominence and the top of the chromospheric spicule layer. Small perturbations on the order of 1 Mm or less in size grow on the upper boundaries of cavities to generate plumes up to 4-6 Mm across at their largest widths. All plumes develop highly turbulent profiles, including occasional Kelvin-Helmholtz vortex 'roll-up' of the leading edge. The flows typically rise 10-15 Mm before decelerating to equilibrium. We measure the flowfield characteristics with a manual tracing method and with the Nonlinear Affine Velocity Estimator (NAVE) 'optical flow' code to derive velocity, acceleration, lifetime, and height data for several representative plumes. Maximum initial speeds are in the range of 20-30 km s{sup -1}, which is supersonic for a {approx}10,000 K plasma. The plumes decelerate in the final few Mm of their trajectories resulting in mean ascent speeds of 13-17 km s{sup -1}. Typical lifetimes range from 300 to 1000 s ({approx}5-15 minutes). The area growth rate of the plumes (observed as two-dimensional objects in the plane of the sky) is initially linear and ranges from 20,000 to 30,000 km{sup 2} s{sup -1} reaching maximum projected areas from 2 to 15 Mm{sup 2}. Maximum contrast of the dark flows relative to the bright prominence plasma in SOT images is negative and ranges from -10% for smaller flows to -50% for larger flows. Passive scalar 'cork movies' derived from NAVE measurements show that prominence plasma is entrained by the upflows, helping to counter the ubiquitous downflow streams in the prominence. Plume formation shows no clear temporal periodicity. However, it is common to find 'active cavities' beneath prominences that can spawn many upflows in succession before going dormant. The mean flow recurrence time in these active locations is roughly 300-500 s (5-8 minutes). Locations remain active on timescales of tens of minutes up to several hours. Using a column density ratio measurement and reasonable assumptions on plume and prominence geometries, we estimate that the mass density in the dark cavities is at most 20% of the visible prominence density, implying that a single large plume could supply up to 1% of the mass of a typical quiescent prominence. We hypothesize that the plumes are generated from a Rayleigh-Taylor instability taking place on the boundary between the buoyant cavities and the overlying prominence. Characteristics, such as plume size and frequency, may be modulated by the strength and direction of the cavity magnetic field relative to the prominence magnetic field. We conclude that buoyant plumes are a source of quiescent prominence mass as well as a mechanism by which prominence plasma is advected upward, countering constant gravitational drainage.
Berger, Thomas E.; Slater, Gregory; Hurlburt, Neal; Shine, Richard; Tarbell, Theodore; Title, Alan [Lockheed Martin Solar and Astrophysics Laboratory, B/252, 3251 Hanover Street, Palo Alto, CA 94304 (United States); Lites, Bruce W. [High Altitude Observatory, University Center for Atmospheric Research, Boulder, CO (United States); Okamoto, Takenori J.; Ichimoto, Kiyoshi; Katsukawa, Yukio; Magara, Tetsuya; Suematsu, Yoshinori [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Shimizu, Toshifumi, E-mail: firstname.lastname@example.com [Institute of Space and Astronautical Science/Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229-8510 (Japan)
Development of mullite substrates and containers. Silicon sheet growth development for the Large Area Silicon Sheet Task of the Low-Cost Silicon Solar array Project. Quarterly report No. 1, October 6, 1977--November 14, 1977
Eight mullite bodies of varied compositions and microstructures have been prepared and are being characterized. These compositions will be submersed in molten silicon to study the impurity and surface effects. These various mullite materials will be analyzed for use as substrates for Honeywell Contract No. 954356, silicon on ceramic program and for use as a container of molten silicon. Low cost processing methods are being developed and evaluated for manufacturing large mullite sheets and mullite containers. At present, a state-of-the-art roll compaction process has shown promising initial results for substrates. However, these 0.5mm x 10cm x 1m are extremely fragile. Slip casting or iso pressing are anticipated for containers.
Wirth, D.G.; Sibold, J.D.
Design of a telescope-occulter system for THEIA
The Telescope for Habitable Exoplanets and Interstellar/Intergalactic Astronomy (THEIA) is a mission concept study for a flagship-class telescope-occulter system to search for terrestrial planets and perform general astrophysics with a space-based 4m telescope. A number of design options were considered for the occulter and telescope optical systems; in this paper we discuss the design of occulters and coronagraphs for THEIA and examine their merits. We present two optimized occulters: a 25.6m-radius occulter with 19m petals that achieves 10^-12 suppression from 250-1000nm with a 75mas inner working angle, and a 20.0m-radius occulter with 10m petals that achieves 10^-12 suppression from 250-700nm with a 75mas inner working angle. For more widely separated planets (IWA > 108mas), this second occulter is designed to operate at a second closer distance where it provides 10^-12 suppression from 700-1000nm. We have also explored occulter/coronagraph hybrid systems, and found that an AIC coronagraph that exploits t...
Cady, Eric; Dumont, Philip; Egerman, Robert; Kasdin, N Jeremy; Linfield, Roger; Lisman, Doug; Savransky, Dmitry; Seager, Sara; Shaklan, Stuart; Spergel, David; Tenerelli, Domenick; Vanderbei, Robert
Google Sky, WorldWide Telescope & Celestia in the
Google Sky, WorldWide Telescope & Celestia in the Undergraduate Non-Science Major Classroom & Lab of Public Outreach Dept.Astronomy & Astrophysics University of Chicago Sky #12;Google Sky, World interactive labs and self-directed modules that utilize new, emerging, software tools, specifically Google Sky
Collar, Juan I.
TeV Dark Matter detection by Atmospheric Cerenkov Telescopes
Ground based Atmospheric Cerenkov Telescopes have recently unveiled a TeV gamma-ray signal from the direction of the Galactic Centre. We examine whether these gamma-rays, observed by the VERITAS, CANGAROO-II and HESS collaborations, may arise from annihilations of dark matter particles. Emission from nearby dwarf spheroidals, such as Sagittarius, could provide a test of this scenario.
Francesc Ferrer
Indirect Search for Dark Matter with the ANTARES Neutrino Telescope
One of the goals of the ANTARES underwater neutrino telescope is the search for dark matter in the universe. In this paper the first results on the search for dark matter in the Sun with ANTARES in its 5 line configuration, as well as sensitivity studies with the full ANTARES detector are presented.
Loucatos, S. [IRFU-SPP, CEA-Saclay, 91191 Gif sur Yvette (France)
A Compact High Energy Camera for the Cherenkov Telescope Array
The Compact High Energy Camera (CHEC) is a camera-development project involving UK, US, Japanese and Dutch institutes for the dual-mirror Small-Sized Telescopes (SST-2M) of the Cherenkov Telescope Array (CTA). Two CHEC prototypes, based on different photosensors are funded and will be assembled and tested in the UK over the next ~18 months. CHEC is designed to record flashes of Cherenkov light lasting from a few to a hundred nanoseconds, with typical RMS image width and length of ~0.2 x 1.0 degrees, and has a 9 degree field of view. The physical camera geometry is dictated by the telescope optics: a curved focal surface with radius of curvature 1m and diameter ~35cm is required. CHEC is designed to work with both the ASTRI and GATE SST-2M telescope structures and will include an internal LED flasher system for calibration. The first CHEC prototype will be based on multi-anode photomultipliers (MAPMs) and the second on silicon photomultipliers (SiPMs or MPPCs). The first prototype will soon be installed on the...
Daniel, M K; Berge, D; Buckley, J; Chadwick, P M; Cotter, G; Funk, S; Greenshaw, T; Hidaka, N; Hinton, J; Lapington, J; Markoff, S; Moore, P; Nolan, S; Ohm, S; Okumura, A; Ross, D; Sapozhnikov, L; Schmoll, J; Sutcliffe, P; Sykes, J; Tajima, H; Varner, G S; Vandenbroucke, J; Vink, J; Williams, D
Radiological Areas
Revision to Clearance Policy Associated with Recycle of Scrap Metals Originating from Revision to Clearance Policy Associated with Recycle of Scrap Metals Originating from Radiological Areas On July 13, 2000, the Secretary of Energy imposed an agency-wide suspension on the unrestricted release of scrap metal originating from radiological areas at Department of Energy (DOE) facilities for the purpose of recycling. The suspension was imposed in response to concerns from the general public and industry groups about the potential effects of radioactivity in or on material released in accordance with requirements established in DOE Order 5400.5, Radiation Protection of the Public and Environment. The suspension was to remain in force until DOE developed and implemented improvements in, and better informed the public about, its release process. In addition, in 2001 the DOE announced its intention to prepare a
Simulation and analysis of laser guide star adaptive optics systems for the eight to ten meter class telescopes
This paper discusses the design and analysis of laser-guided adaptive optic systems for the large, 8--10 meter class telescopes. We describe a technique for calculating the expected modulation transfer function and the point spread function for a closed loop adaptive optics system, parameterized by the degree of correction and the seeing conditions. The results agree closely with simulations and experimental data, and validate well known scaling law models even at low order correction. Scaling law.model analysis of a proposed adaptive optics system at the Keck telescope leads to the conclusion that a single laser guide star beacon will be adequate for diffraction limited imaging at wavelengths between 1 and 3 am with reasonable coverage of the sky. Cone anisoplanatism will dominate wavefront correction error at the visible wavelengths unless multiple laser guide stars are used.
Gavel, D.T.; Olivier, S.S.
Slicing of silicon into sheet material. Silicon sheet growth development for the large area silicon sheet task of the low cost silicon solar array project. Sixth quarterly report, June 18, 1977--September 18, 1977
The ''Multiple Blade Alignment Device'' has been reported to JPL as a New Technology item, and is currently being reviewed for patent potential. The device has proven difficult to install on a blade package. Successful engagement of the device has resulted in an intrinsic parallelism of the ends of the package to within 3..mu.., compared to standard errors prior to correction of over 50..mu... Measurements of blade misalignment indicate an average runout of 50..mu.. in a 220 blade package. This compares well with predictions based on thickness variation measurements of blades and spacers. Early cutting tests with 0.15 mm blades and 10 cm diameter ingots show lower yield and accuracy and higher cutting speed than previous standard tests. This seems to be a result of effective high abrasive concentration on the blades as a result of the slurry application technique. A similar, more dramatic reduction of yield occurs with a thin slurry oil. This appears to occur by increased slurry transport to the blades and another effective increase of abrasive packing to the cutting region. Design of the large capacity MS saw is proceeding well, with a final conceptual design in progress. A flywheel system for work-piece drive is described. The design offers a practical conservative motion for the drive, requiring a minimum of power. 10 cm MS slices have been sent out for solar cell fabrication. 10 cm diameter and 2 cm square MS slices have been delivered for various surface preparations, and will be fabricated into cells and evaluated for performance. This will develop a minimum surface removal technique for both the damage and profiles peculiar to thin MS sices while allowing high efficiency cell production.
Holden, S.C.; Fleming, J.R.
Heat exchanger-ingot casting/slicing process. Silicon sheet growth development for the Large Area Silicon Sheet Task of the Low Cost Silicon Solar Array Project. Final report, Phase I, November 20, 1975--November 20, 1977
The proof of concept for silicon casting by the Heat Exchanger Method has been established. One of the major hurdles of ingot cracking has been eliminated with the development of graded crucibles. Such crucibles are compatible with the casting process in that the integrity of the container is maintained at high temperature; however, during the cool-down cycle the crucible fails, thereby leaving a crack-free boule. The controlled growth, heat-flow and cool-down has yielded silicon with a high degree of single crystallinity. Even when the seed melted out, very large grains formed. Solar cell samples made from cast material have yielded conversion efficiency of over 9% (AMI). Representative characterizations of silicon grown has demonstrated a dislocation density of less than 100/cm/sup 2/ and a minority carrier diffusion length of 31 ..mu..m. Excellent surface quality, i.e., surface smoothness and 3 to 5 ..mu..m surface damage, was achieved by multiple wire slicing with fixed diamond abrasive. To achieve this, the silicon workpiece was non-synchronously rocked to produce a radial cut profile and minimize wire contact length. Wire wander was reduced an order of magnitude over the original results by supporting and guiding the wires with grooved rollers. Commercially available impregnated wires that were used failed due to diamond pull-out. Plating after impregnation or electroplating diamonds directly on the core minimized diamond pull-out and corresponding loss in cutting effectiveness. Tungsten wire was the best core material tested because of its high strength, high Young's modulus, and resistance to hydrogen embrittlement. A lighter and longer blade carriage can be used for slicing with wire. This will allow the blade carriage to be reciprocated more rapidly to increase the surface speed. A projected add-on cost calculation shows that these methods will yield silicon for solar cell applications within ERDA/JPL cost goals.
Schmid, F; Khattak, C P
The Taiwanese-American Occultation Survey: The Multi-Telescope Robotic Observatory
The Taiwanese-American Occultation Survey (TAOS) operates four telescopes to search for occultations of stars by Kuiper Belt Objects. This paper provides a detailed description of the TAOS multi-telescope system.
Lehner, M J; Wang, J -H; Marshall, S L; Schwamb, M E; Zhang, Z -W; Bianco, F B; Giammarco, J; Porrata, R; Alcock, C; Axelrod, T; Byun, Y -I; Chen, W P; Cook, K H; Davé, R; King, S -K; Lee, T; Lin, H -C; Wang, S -Y
TARGET: A multi-channel digitizer chip for very-high-energy gamma-ray telescopes
The next-generation very-high-energy (VHE) gamma-ray observatory, the Cherenkov Telescope Array, will feature dozens of imaging atmospheric Cherenkov telescopes (IACTs), each with thousands of pixels of photosensors. To be affordable and reliable, reading out such a mega-channel array requires event recording technology that is highly integrated and modular, with a low cost per channel. We present the design and performance of a chip targeted to this application: the TeV Array Readout with GSa/s sampling and Event Trigger (TARGET). This application-specific integrated circuit (ASIC) has 16 parallel input channels, a 4096-sample buffer for each channel, adjustable input termination, self-trigger functionality, and tight window-selected readout. We report the performance of TARGET in terms of sampling frequency, power consumption, dynamic range, current-mode gain, analog bandwidth, and cross talk. The large number of channels per chip allows a low cost per channel ($10 to $20 including front-end and back-end electronics but not including photosensors) to be achieved with a TARGET-based IACT readout system. In addition to basic performance parameters of the TARGET chip itself, we present a camera module prototype as well as a second-generation chip (TARGET 2), both of which have been produced.
Bechtol, K.; Funk, S.; /Stanford U., HEPL /KIPAC, Menlo Park; Okumura, A.; /JAXA, Sagamihara /Stanford U., HEPL /KIPAC, Menlo Park; Ruckman, L.; /Hawaii U.; Simons, A.; Tajima, H.; Vandenbroucke, J.; /Stanford U., HEPL /KIPAC, Menlo Park; Varner, G.; /Hawaii U.
A Strategy for Finding Near Earth Objects with the SDSS Telescope
We present a detailed observational strategy for finding Near Earth Objects (NEOs) with the Sloan Digital Sky Survey (SDSS) telescope. We investigate strategies in normal, unbinned mode as well as binning the CCDs 2x2 or 3x3, which affects the sky coverage rate and the limiting apparent magnitude. We present results from 1 month, 3 year and 10 year simulations of such surveys. For each cadence and binning mode, we evaluate the possibility of achieving the Spaceguard goal of detecting 90% of 1 km NEOs (absolute magnitude H <= 18 for an albedo of 0.1). We find that an unbinned survey is most effective at detecting H <= 20 NEOs in our sample. However, a 3x3 binned survey reaches the Spaceguard Goal after only seven years of operation. As the proposed large survey telescopes (PanStarss; LSST) are at least 5-10 years from operation, an SDSS NEO survey could make a significant contribution to the detection and photometric characterization of the NEO population.
Sean N. Raymond; Oliver J. Fraser; Arti Garg; Suzanne L. Hawley; Robert Jedicke; Gajus Miknaitis; Thomas Quinn; Constance M. Rockosi; Christopher W. Stubbs; Scott F. Anderson; Craig J. Hogan; Zeljko Ivezic; Robert H. Lupton; Andrew A. West; Howard Brewington; J. Brinkmann; Michael Harvanek; Scot J. Kleinman; Jurek Krzesinski; Dan Long; Eric H. Neilsen; Peter R. Newman; Atsuko Nitta; Stephanie A. Snedden
Raymond, S N; Garg, A; Hawley, S L; Jedicke, R; Miknaitis, G; Quinn, T; Rockosi, C M; Stubbs, C W; Anderson, S F; Hogan, C J; Ivezic, Z; Lupton, R H; West, A A; Brewington, H; Brinkmann, J; Harvanek, M J; Kleinman, S J; Krzesínski, J; Long, D; Neilsen, E H; Newman, P R; Nitta, A; Snedden, S A; Raymond, Sean N.; Fraser, Oliver J.; Garg, Arti; Hawley, Suzanne L.; Jedicke, Robert; Miknaitis, Gajus; Quinn, Thomas; Rockosi, Constance M.; Stubbs, Christopher W.; Anderson, Scott F.; Hogan, Craig J.; Ivezic, Zeljko; Lupton, Robert H.; West, Andrew A.; Brewington, Howard; Harvanek, Michael; Kleinman, Scot J.; Krzesinski, Jurek; Long, Dan; Neilsen, Eric H.; Newman, Peter R.; Nitta, Atsuko; Snedden, Stephanie A.
The ANTARES Neutrino Telescope: status and first results
Completed in May 2008, the ANTARES neutrino telescope is located in the Mediterranean Sea, 40 km off the coast of Toulon, at a depth of about 2500 m. Consisting of 12 detector lines housing nearly 900 optical modules, the ANTARES telescope is currently the largest neutrino detector in the northern hemisphere. Utilising the Mediterranean Sea as a detecting medium, the detection principle of ANTARES relies on the observation of Cherenkov photons emitted by charged relativistic leptons, produced through neutrino interactions with the surrounding water and seabed, using a 3 dimensional lattice of photomultiplier tubes. In this paper we review the current status of the ANTARES experiment, highlighting some of the results from it's first year of full operation.
Thermal characteristics of a classical solar telescope primary mirror
We present a detailed thermal and structural analysis of a 2m class solar telescope mirror which is subjected to a varying heat load at an observatory site. A 3-dimensional heat transfer model of the mirror takes into account the heating caused by a smooth and gradual increase of the solar flux during the day-time observations and cooling resulting from the exponentially decaying ambient temperature at night. The thermal and structural response of two competing materials for optical telescopes, namely Silicon Carbide -best known for excellent heat conductivity and Zerodur -preferred for its extremely low coefficient of thermal expansion, is investigated in detail. The insight gained from these simulations will provide a valuable input for devising an efficient and stable thermal control system for the primary mirror.
Banyal, Ravinder K
Design of light concentrators for Cherenkov telescope observatories
The Cherenkov Telescope Array (CTA) will be the largest cosmic gamma ray detector ever built in the world. It will be installed at two different sites in the North and South hemispheres and should be operational for about 30 years. In order to cover the desired energy range, the CTA is composed of typically 50-100 collecting telescopes of various sizes (from 6 to 24-m diameters). Most of them are equipped with a focal plane camera consisting of 1500 to 2000 Photomultipliers (PM) equipped with light concentrating optics, whose double function is to maximize the amount of Cherenkov light detected by the photo-sensors, and to block any stray light originating from the terrestrial environment. Two different optical solutions have been designed, respectively based on a Compound Parabolic Concentrator (CPC), and on a purely dioptric concentrating lens. In this communication are described the technical specifications, optical designs and performance of the different solutions envisioned for all these light concentra...
Hénault, F; jocou, L; Khélifi, B; Manigot, P; Hormigos, S; Knodlseder, J; Olive, J F; Jean, P; Punch, M
Observation of GRBs by the MAGIC Telescope, Status and Outlook
Observation of Gamma Ray Bursts (GRBs) in the Very High Energy (VHE) domain will provide important information on the physical conditions in GRB outflows. The MAGIC telescope is the best suited Imaging Atmospheric Cherenkov Telescope (IACT) for these observations. Thanks to its fast repositioning time and low energy threshold, MAGIC is able to start quickly the follow-up observation, triggered by an alert from the GRB Coordinates Network (GCN), and observe the prompt emission and early afterglow phase from GRBs. In the last two years of operation several GRB follow-up observations were performed by MAGIC, however, until now without successful detection of VHE gamma rays above threshold energies >100 GeV. In this paper we revise the expectations for the GRB observations with MAGIC, based on the experience from the last years of operation.
D. Bastieri; N. Galante; M. Garczarczyk; M. Gaug; F. Longo; S. Mizobuchi; V. Scapin
Minimal Stereoscopic Analysis for Imaging Atmospheric Cherenkov Telescope Arrays
The trajectory of a primary gamma-ray detected with an array of at least four atmospheric Cherenkov imaging telescopes can be reconstructed from the shower image centroid positions and geometrical considerations independent of the primary energy. Using only the image centroid positions some cosmic-ray discrimination is also possible. This minimal approach opens the possibility of pushing the analysis threshold to lower values, close to the hardware threshold.
S. LeBohec; C. Duke; P. Jordan
Large forging manufacturing process
A process for forging large components of Alloy 718 material so that the components do not exhibit abnormal grain growth includes the steps of: a) providing a billet with an average grain size between ASTM 0 and ASTM 3; b) heating the billet to a temperature of between 1750.degree. F. and 1800.degree. F.; c) upsetting the billet to obtain a component part with a minimum strain of 0.125 in at least selected areas of the part; d) reheating the component part to a temperature between 1750.degree. F. and 1800.degree. F.; e) upsetting the component part to a final configuration such that said selected areas receive no strains between 0.01 and 0.125; f) solution treating the component part at a temperature of between 1725.degree. F. and 1750.degree. F.; and g) aging the component part over predetermined times at different temperatures. A modified process achieves abnormal grain growth in selected areas of a component where desirable.
Thamboo, Samuel V. (Latham, NY); Yang, Ling (Niskayuna, NY)
A Central Laser Facility for the Cherenkov Telescope Array
A Central Laser Facility is a system often used in astroparticle experiments based on arrays of fluorescence or Cherenkov light detectors. The instrument is based on a laser source positioned at a certain distance from the array, emitting fast light pulses in the vertical direction with the aim of calibrating the array and/or measuring the atmospheric transmission. In view of the future Cherenkov Telescope Array (CTA), a similar device could provide a calibration of the whole installation, both relative, i.e. each individual telescope with respect to the rest of the array, and absolute, with a precision better than 10%, if certain design requirements are met. Additionally, a precise monitoring of the sensitivity of each telescope can be made on time-scales of days to years. During calibration runs of the central laser facility, all detectors will be pointed towards the same portion of the laser beam at a given altitude. Simulations of the possible configurations of a Central Laser Facility for CTA (varying la...
Gaug, Markus; Cilmo, Marco; Di Pierro, Federico; Tonachini, Aurelio; Vallania, Piero
Tests & Calibration on Ultra Violet Imaging Telescope (UVIT)
Ultra Violet Imaging Telescope on ASTROSAT Satellite mission is a suite of Far Ultra Violet (FUV; 130 to 180 nm), Near Ultra Violet (NUV; 200 to 300 nm) and Visible band (VIS; 320 to 550nm) imagers. ASTROSAT is a first multi wavelength mission of INDIA. UVIT will image the selected regions of the sky simultaneously in three channels & observe young stars, galaxies, bright UV Sources. FOV in each of the 3 channels is about 28 arc-minute. Targeted angular resolution in the resulting UV images is better than 1.8 arc-second (better than 2.0 arc-second for the visible channel). Two identical co-aligned telescopes (T1, T2) of Ritchey-Chretien configuration (Primary mirror of 375 mm diameter) collect the celestial radiation and feed to the detector system via a selectable filter on a filter wheel mechanism; gratings are available in the filter wheels of FUV and NUV channels for slit-less low resolution spectroscopy. The detector system for each of the 3 channels is generically identical. One telescope images in ...
Kumar, Amit; Kamath, P U; Postma, Joe; Kathiravan, S; Mahesh, P K; S, Nagbhushana; Navalgund, K H; Rajkumar, N; Rao, M N; Sarma, K S; Sriram, S; Stalin, C S; Tandon, S N
Transmission of light in deep sea water at the site of the Antares neutrino telescope
The ANTARES neutrino telescope is a large photomultiplier array designed to detect neutrino-induced upward-going muons by their Cherenkov radiation. Understanding the absorption and scattering of light in the deep Mediterranean is fundamental to optimising the design and performance of the detector. This paper presents measurements of blue and UV light transmission at the ANTARES site taken between 1997 and 2000. The derived values for the scattering length and the angular distribution of particulate scattering were found to be highly correlated, and results are therefore presented in terms of an absorption length lambda_abs and an effective scattering length lambda_sct^eff. The values for blue (UV) light are found to be lambda_abs ~ 60(26) m, lambda_sct^eff ~ 265(122) m, with significant (15%) time variability. Finally, the results of ANTARES simulations showing the effect of these water properties on the anticipated performance of the detector are presented.
ANTARES collaboration
The Prototype of the Small Synoptic Second Solar Spectrum Telescope (S5T)
We present the design and the prototype of the Small Synoptic Second Solar Spectrum Telescope (S5T), which can autonomously measure scattering polarization signals on a daily basis with large sensitivity and accuracy. Its data will be used to investigate the nature of weak, turbulent magnetic fields through the Hanle effect in many lines. Also the relation between those fields and the global solar dynamo can be revealed by spanning the observations over a significant fraction of a solar cycle. The compact instrument concept is enabled by a radial polarization converter that allows for ``one-shot'' polarimetry over the entire limb of the Sun. A polarimetric sensitivity of ~10^-5 is achieved by minimizing the instrumental polarization and by FLC modulation in combination with a fast line-scan camera in the fiber-fed spectrograph. The first prototype results successfully show the feasibility of the concept.
Snik, Frans; Keller, Christoph
2. The metal is heated in the boiler (typically to 550°C) totempera ture than the boiler to minimize the fraction ofbeen employed. Ł4.5) VALVE BOILER X L 7911-12695 B Fig. 2.
Poulsen, P.
Soil Organic Carbon Change Monitored Over Large Areas
Soils account for the largest fraction of terrestrial carbon (C); thus, they are critically important in determining global C cycle dynamics. In North America, conversion of native prairies to agricultural land use over 150 years ago released 30-50% of the soil organic carbon (SOC). Improved agricultural practices have the capacity to recover much of this SOC, storing it in biomass and soil and thereby removing billions of tons of atmospheric CO2. These practices involve increasing C inputs to soil (e.g., by crop rotations, increased use of higher biomass crops, perennial crops) and decreased losses (e.g., reduced tillage intensity) [Janzen et al., 1998; Lal et al., 2003; Smith et al., 2007]. Managing agricultural soils to increase SOC storage is a significant, immediately available, low-cost option for mitigating CO2 emissions, with a technical potential to offset as much as 800 Tg CO2/yr in the US (~13% of US CO2 emissions) [Lal et al., 2003] and 5000 Tg CO2/yr globally (~17% of global CO2 emissions) [Smith et al., 2007].
Brown, David J.; Hunt, E. Raymond; Izaurralde, Roberto C.; Paustian, Keith H.; Rice, Charles W.; West, Tristram O.; Schumaker, Bonny L.
Managing agricultural soils to increase SOC storage is a significant, immediately available, low-cost option for mitigating CO2 emissions, with the technical potential to sequester as much as 800 Tg CO2/yr in the US (~13% of US CO2 emissions) [Lal et al., 2003] and 5000 Tg CO2/yr globally (~17% of global CO2 emissions) [Smith et al., 2007].
Brown, David J.; Hunt, Earle R.; Izaurralde, Roberto C.; Paustian, Keith H.; Rice, Charles W.; schumaker, Bonny L.; West, Tristram O.
Large area liquid argon detectors for interrogation systems
Measurements of the efficiency, pulse shape, and energy and time resolution of liquid argon (LAr) detectors are presented. Liquefied noble gas-based (LNbG) detectors have been developed for the detection of dark matter and neutrinoless double-beta decay. However, the same qualities that make LNbG detectors ideal for these applications, namely their size, cost, efficiency, pulse shape discrimination and resolution, make them promising for portal screening and the detection of Special Nuclear Materials (SNM). Two 18-liter prototype detectors were designed, fabricated, and tested, one with pure LAr and the other doped with liquid Xe (LArXe). The LArXe detector presented the better time and energy resolution of 3.3 ns and 20% at 662 KeV, respectively. The total efficiency of the detector was measured to be 35% with 4.5% of the total photons detected in the photopeak.
Gary, Charles; Kane, Steve; Firestone, Murray I.; Smith, Gregory [Adelphi Technology LLC, Purdue Technology Center, 5225 Exploration Drive, Indianapolis, IN 46241 (United States); Gozani, Tsahi; Brown, Craig; Kwong, John; King, Michael J. [Rapiscan Laboratories, 520 Almanor Avenue, Sunnyvale, CA 94085 (United States); Nikkel, James A.; McKinsey, Dan [Physics Department, Yale University, New Haven, CT 06520 (United States)
Organic-free suspension of large-area graphene
We report an entirely organic-free method to suspend monolayer graphene grown by chemical vapour deposition over 10-20 {mu}m apertures in a Cu substrate. Auger electron spectroscopy, Raman spectroscopy, scanning electron microscope, and transmission electron microscope measurements confirm high quality graphene with no measurable contamination beyond that resulting from air exposure. This method can be used to prepare graphene for fundamental studies and applications where the utmost cleanliness and structural integrity are required.
Ledwosinska, E.; Gaskell, P.; Szkopek, T. [Regroupement Quebecois sur les Materiaux de Pointe, Montreal, Quebec H3C 3J7 (Canada); Department of Electrical and Computer Engineering, McGill University, Montreal, Quebec H3A 0E9 (Canada); Guermoune, A.; Siaj, M. [Centre Quebecois sur les Materiaux Fonctionnels, Quebec, Quebec G1V 0A6 (Canada); Department de Chimie, Universite du Quebec a Montreal, Montreal, Quebec H3C 3P8 (Canada)
Plasma and Ion Sources in Large Area Coatings: A Review
A. Popov, "High Density Plasma Sources," Park Ridge, N.J. :et al. , IEEE Trans. Plasma Sci. 26 (1998) J. Pelletier, "R. Winter, and J. Engemann, Plasma Sources Sci. Technol. I.
Anders, Andre
high transmittance of indium tin oxide (ITO) [32]. 5. Largethe deposition of indium tin oxide (ITO), SiO 2 , and copper
Soils account for the largest fraction of terrestrial carbon (C) and thus are critically important in determining global cycle dynamics. In North America, conversion of native prairies to agriculture over the past 150 years released 30- 50% of soil organic carbon (SOC) stores [Mann, 1986]. Improved agricultural practices could recover much of this SOC, storing it in biomass and soil and thereby sequestering billions of tons of atmospheric carbon dioxide (CO2). These practices involve increasing C inputs to soil (e.g., through crop rotation, higher biomass crops, and perennial crops) and decreasing losses (e.g., through reduced tillage intensity) [Janzen et al., 1998; Lal et al., 2003; Smith et al., 2007].
Brown, David J.; Hunt, E. Raymond; Izaurralde, Roberto C.; Paustian, Keith H.; Rice, Charles W.; Schumaker, Bonny L.; West, Tristram O.
Large area 3-D reconstructions from underwater optical surveys
Robotic underwater vehicles are regularly performing vast optical surveys of the ocean floor. Scientists value these surveys since optical images offer high levels of detail and are easily interpreted by humans. Unfortunately, ...
Singh, Hanumant
X-ray Detection with Large Area Avalanche Photodiodes for ...
... The primary photon detector was a 12-element ... The overall energy range for the experiment was ... to directly detect X-rays with energies between 0.3 ...
Engineering light using large area photonic crystal devices
Photonic crystals are fabricated structures composed of a periodic arrangement of materials with differing indices of refraction. This research has focused on the realization of two distinct photonic crystal structures in ...
Tandon, Sheila (Sheila N.), 1978-
Engineering light using large area photonic crystal devices.
??Photonic crystals are fabricated structures composed of a periodic arrangement of materials with differing indices of refraction. This research has focused on the realization of… (more)
High-efficiency large-area CdTe panels
The objective of this three year effort has been to develop an improved materials technology and fabrication process for limited volume production of 1 ft{sup 2} and 4 ft{sup 2} CdS/CdTe photovoltaic modules. The module stability objective by the end of this three year subcontract was to develop techniques to provide ten year life exploration with no greater than 10% degradation. In order to achieve these efficiency and stability objectives, the research program has been separated into tasks including: (1) analysis and characterization of CdS/CdTe Devices; (2) performance optimization on small cells; (3) encapsulation and stability testing; and (4) module efficiency optimization. 27 refs., 18 figs., 3 tabs.
Albright, S.P.; Chamberlin, R.R.; Jordan, J.F. (Photon Energy, Inc., El Paso, TX (USA))
Fast segmentation of large images
The processing of large images is a generic problem in wide area surveillance. An important difficulty is that many image processing algorithms are global rather than local and hence can be infeasible due to the required computing time or memory resources ... Keywords: algorithm, image, segmentation
David J. Crisp; Peter Perry; Nicholas J. Redding
The SiRi Particle-Telescope System
A silicon particle-telescope system for light-ion nuclear reactions is described. In particular, the system is designed to be optimized for level density and gamma-ray strength function measurements with the so-called Oslo method. Eight trapezoidal modules are mounted at 5 cm distance from the target, covering 8 forward angles between theta = 40 and 54 degrees. The thin front dE detectors (130 micrometer) are segmented into eight pads, determining the reaction angle for the outgoing charged ejectile. Guard rings on the thick back E detectors (1550 micrometer) guarantee low leakage current at high depletion voltage.
M. Guttormsen; A. Bürger; T. E. Hansen; N. Lietaer
Six years of GRB follow up with MITSuME Okayama Telescope
MITSuME Okayama Telescope is an autonomous telescope with a diameter of 50 cm dedicated primarily to follow-up {gamma}-ray bursts. The telescope has successfully been in operation since 2004. We have made 131 observations of {gamma}-ray bursts and submitted 47 reports to GCN circulars. In this article, we present an overview of the instrumentation and scientific results obtained so far.
Yanagisawa, Kenshi; Kuroda, Daisuke; Shimizu, Yasuhiro; Nagayama, Shogo; Toda, Hiroyuki [Okayama Astrophysical Observatory, Kamogata, Asakuchi, Okayama 719-0232 (Japan); Yoshida, Michitoshi [Hiroshima University, Higashi-Hiroshima, Hiroshima, 739-8526 (Japan); Ohta, Kouji [Kyoto University, Sakyo-ku, Kita-shirakawa, Kyoto, 606-8502 (Japan); Kawai, Nobuyuki [Tokyo Institute of Technology, Ookayama, Meguro, Tokyo, 152-8551 (Japan)
Deployable telescope having a thin-film mirror and metering structure
A deployable thin-film mirror telescope comprises a base structure and a metering structure. The base structure houses a thin-film mirror, which can be rolled for stowage and unrolled for deployment. The metering structure is coupled to the base structure and can be folded for stowage and unfolded for deployment. In the deployed state, the unrolled thin-film mirror forms a primary minor for the telescope and the unfolded metering structure positions a secondary minor for the telescope.
Krumel, Leslie J. (Cedar Crest, NM); Martin, Jeffrey W. (Albuquerque, NM)
Large-Eddy Simulation: How Large is Large Enough?
The length scale evolution of various quantities in a clear convective boundary layer (CBL), a stratocumulus-topped boundary layer, and three radiatively cooled ("smoke cloud") convective boundary layers are studied by means of large-eddy ...
Stephan R. de Roode; Peter G. Duynkerke; Harm J. J. Jonker
On the detection of relativistic magnetic monopoles by deep underwater and underice neutrino telescopes
I present here some reflections and very speculative remarks on the detection of relativistic magnetic monopoles by currently operating deep underwater/ice neutrino telescopes.
B. K. Lubsandorzhiev
We studied bright umbral dots (UDs) detected in a moderate size sunspot and compared their statistical properties to recent MHD models. The study is based on high-resolution data recorded by the New Solar Telescope at the Big Bear Solar Observatory and three-dimensional (3D) MHD simulations of sunspots. Observed UDs, living longer than 150 s, were detected and tracked in a 46 minute long data set, using an automatic detection code. A total of 1553 (620) UDs were detected in the photospheric (low chromospheric) data. Our main findings are (1) none of the analyzed UDs is precisely circular, (2) the diameter-intensity relationship only holds in bright umbral areas, and (3) UD velocities are inversely related to their lifetime. While nearly all photospheric UDs can be identified in the low chromospheric images, some small closely spaced UDs appear in the low chromosphere as a single cluster. Slow-moving and long-living UDs seem to exist in both the low chromosphere and photosphere, while fast-moving and short-living UDs are mainly detected in the photospheric images. Comparison to the 3D MHD simulations showed that both types of UDs display, on average, very similar statistical characteristics. However, (1) the average number of observed UDs per unit area is smaller than that of the model UDs, and (2) on average, the diameter of model UDs is slightly larger than that of observed ones.
Kilcik, A.; Yurchyshyn, V. B.; Abramenko, V.; Goode, P. R.; Cao, W. [Big Bear Solar Observatory, Big Bear City, CA 92314 (United States); Rempel, M. [High Altitude Observatory, NCAR, Boulder, CO 80307-3000 (United States); Kitai, R.; Watanabe, H. [Kwasan and Hida Observatories, Kyoto University, Kyoto 607-8417 (Japan)
The Ultraviolet Imaging Telescope: Instrument and Data Characteristics
The Ultraviolet Imaging Telescope (UIT) was flown as part of the Astro observatory on the Space Shuttle Columbia in December 1990 and again on the Space Shuttle Endeavor in March 1995. Ultraviolet (1200-3300?A) images of a variety of astronomical objects, with a 40 ? field of view and a resolution of about 3 ? ? , were recorded on photographic film. The data recorded during the first flight are available to the astronomical community through the National Space Science Data Center (NSSDC); the data recorded during the second flight will soon be available as well. This paper discusses in detail the design, operation, data reduction, and calibration of UIT, providing the user of the data with information for understanding and using the data. It also provides guidelines for analyzing other astronomical imagery made with image intensifiers and photographic film. – 3 –
Theodore P. Stecher; Robert H. Cornett; Michael R. Greason; Wayne B. L; Jesse K. Hill; Robert S. Hill; Ralph C. Bohlin; Peter C. Chen; Nicholas R; Michael N. Fanelli; Joan I. Hollis; Susan G. Neff; Robert W. O'connell; Joel D. Offenberg; Ronald A. Parise; Joel Wm. Parker; Morton S. Roberts; M. Smith; William H. Waller
Affordable Digital Planetariums with WorldWide Telescope
Digital planetariums can provide a broader range of educational experiences than the more classical planetariums that use star-balls. This is because of their ability to project images, content from current research and the 3D distribution of the stars and galaxies. While there are hundreds of planetariums in the country the reason that few of these are full digital is the cost. In collaboration with Microsoft Research (MSR) we have developed a way to digitize existing planetariums for approximately \\$40,000 using software freely available. We describe here how off the shelf equipment, together with MSR's WorldWide Telescope client can provide a rich and truly interactive experience. This will enable students and the public to pan though multi-wavelength full-sky scientific data sets, explore 3d visualizations of our Solar System (including trajectories of millions of minor planets), near-by stars, and the SDSS galaxy catalog.
Rosenfield, Philip; Fay, Jonathan; Carey, Larry; Sayres, Conor; Tofflemire, Benjamin
Fourier transform method for imaging atmospheric Cherenkov telescopes
We propose Fourier transform (FT) method for processing images of extensive air showers (EAS) detected by imaging atmospheric Cherenkov telescopes (IACT) used in the very high energy (VHE) gamma-ray astronomy. The method is based on the discrete Fourier transforms (DFT) on compact Lie groups, and the use of continuous extension of the inverse discrete transforms to approximate the discrete EAS images by continuous EAS brightness distribution functions. Here we describe the FT-method in case of SU(3) group. It allows practical realization of the DFT technique for functions sampled on hexagonal symmetry grids. The proposed method can also be implemented in case of IACT cameras with grids of rectangular symmetry by using the DFT on the SU(2)xSU(2) group. The proposed FT-method is applied to the Monte-Carlo simulated bank of TeV proton and gamma-ray EAS images for a stand-alone telescope. Comparing between the FT-method and the currently used standard method shows that the FT technique allows a better and systematic enhancement of the gamma-ray signal. The relative difference between these two methods becomes more profound especially for `photon poor' images. It suggests that the EAS detection thresholds of IACTs could be effectively reduced with the use of FT technique. This prediction is further supported by a significant noise suppression capability of the method using simple low-pass filters in the image frequency domain. The FT-method allows very deep `tail' (and `height') image cuts, differentiation of images, operations in the image frequency domain, etc., that can be used for development of new effective parameters for the EAS image processing.
A. Atoyan; J. Patera; V. Sahakian; A. Akpherjanian
A ring-shaped debris disk around the G2V star HD 202628 (d = 24.4 pc) was imaged in scattered light at visible wavelengths using the coronagraphic mode of the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. The ring is inclined by {approx}64 Degree-Sign from face-on, based on the apparent major/minor axis ratio, with the major axis aligned along P.A. = 130 Degree-Sign . It has inner and outer radii (>50% maximum surface brightness) of 139 AU and 193 AU in the northwest ansae and 161 AU and 223 AU in the southeast ({Delta}r/r Almost-Equal-To 0.4). The maximum visible radial extent is {approx}254 AU. With mean surface brightness of V Almost-Equal-To 24 mag arcsec{sup -2}, this is the faintest debris disk observed to date in reflected light. The center of the ring appears offset from the star by {approx}28 AU (deprojected). An ellipse fit to the inner edge has an eccentricity of 0.18 and a = 158 AU. This offset, along with the relatively sharp inner edge of the ring, suggests the influence of a planetary-mass companion. There is a strong similarity with the debris ring around Fomalhaut, though HD 202628 is a more mature star with an estimated age of about 2 Gyr. We also provide surface brightness limits for nine other stars in our study with strong Spitzer excesses around which no debris disks were detected in scattered light (HD 377, HD 7590, HD 38858, HD 45184, HD 73350, HD 135599, HD 145229, HD 187897, and HD 201219).
Krist, John E.; Bryden, Geoffrey [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Stapelfeldt, Karl R. [Laboratory for Exoplanets and Stellar Astrophysics, Code 667, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Plavchan, Peter [NASA Exoplanet Science Institute, California Institute of Technology, 770 S Wilson Ave., Pasadena, CA 91125 (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)
The Taiwanese-American Occultation Survey (TAOS) operates four fully automatic telescopes to search for occultations of stars by Kuiper Belt Objects. It is a versatile facility that is also useful for the study of initial optical GRB afterglows. This paper provides a detailed description of the TAOS multi-telescope system, control software, and high-speed imaging.
M. J. Lehner; C. -Y. Wen; J. -H. Wang; S. L. Marshall; M. E. Schwamb; Z. -W. Zhang; F. B. Bianco; J. Giammarco; R. Porrata; C. Alcock; T. Axelrod; Y. -I. Byun; W. P. Chen; K. H. Cook; R. Dave; S. -K. King; T. Lee; H. -C. Lin; S. -Y. Wang
The Universe Viewed in Gamma-Rays 1 Pachmarhi Array of Cerenkov Telescopes
The Universe Viewed in Gamma-Rays 1 Pachmarhi Array of Cerenkov Telescopes P.Majumdar, B of Cerenkov Telescopes (PACT) has been designed to search for celestial TeV -rays using the wavefront sampling Atmospheric Cerenkov technique is the only method which has been suc- cessfully used to probe the sky
Enomoto, Ryoji
March 18, 2010 James Webb Space Telescope Studies of Dark Energy
March 18, 2010 James Webb Space Telescope Studies of Dark Energy Jonathan P. Gardner (NASA. Introduction The Hubble Space Telescope (HST) has contributed significantly to studies of dark energy) was due to dark energy rather than observational or astrophysical effects such as systematic errors
Sirianni, Marco
Before this decade is out: a student project to place a telescope on the internet
This paper describes a student project to place a telescope on the internet: such a telescope can be pointed via a web interface, and images from it displayed on a user's computer. We discuss recent developments in astronomy hardware and computer software ...
Michael P. Rogers
A 610-MHz Galactic Plane Pulsar Search with the Giant Meterwave Radio Telescope
We report on the discovery of three new pulsars in the first blind survey of the north Galactic plane (45 < l < 135 ; |b| < 1) with the Giant Meterwave Radio telescope (GMRT) at an intermediate frequency of 610 MHz. The timing parameters, obtained in follow up observations with the Lovell Telescope at Jodrell Bank Observatory and the GMRT, are presented.
B. C. Joshi; M. A. McLaughlin; M. Kramer; A. G. Lyne; D. R. Lorimer; D. A. Ludovici; M. Davies; A. J. Faulkner
Experience with the Hubble Space Telescope: 20 years of an archetype
The Hubble Space Telescope's mission is summarized, with special emphasis placed on the Space Telescope Science Institute's unique experience with Hubble's behavior as an astronomical telescope in the environment of low earth orbit for over two decades. Historical context and background are given, and the project's early scientific expectations are described. A general overview of the spacecraft is followed by a more detailed look at the optical design, both as intended and as built. Basic characteristics of the complete complement of science instruments are also summarized. Experience with the telescope on-orbit is reviewed, starting with the major initial problems, solutions, human servicing missions, and the associated expansion of the observatory's capabilities over this time. Specific attention is then given to understanding Hubble's optical quality and pointing/jitter performance, two fundamental characteristics of a telescope. Experience with-and the important mitigation of-radiation damage and contami...
Lallo, Matthew
Large displacement spherical joint
A new class of spherical joints has a very large accessible full cone angle, a property which is beneficial for a wide range of applications. Despite the large cone angles, these joints move freely without singularities.
Bieg, Lothar F. (Albuquerque, NM); Benavides, Gilbert L. (Albuquerque, NM)
The Green Bank Telescope H II Region Discovery Survey (GBT HRDS) found hundreds of previously unknown Galactic regions of massive star formation by detecting hydrogen radio recombination line (RRL) emission from candidate H II region targets. Since the HRDS nebulae lie at large distances from the Sun, they are located in previously unprobed zones of the Galactic disk. Here, we derive the properties of helium and carbon RRL emission from HRDS nebulae. Our target sample is the subset of the HRDS that has visible helium or carbon RRLs. This criterion gives a total of 84 velocity components (14% of the HRDS) with helium emission and 52 (9%) with carbon emission. For our highest quality sources, the average {sup 4}He{sup +}/H{sup +} abundance ratio by number, (y {sup +}), is 0.068 {+-} 0.023(1{sigma}). This is the same ratio as that measured for the sample of previously known Galactic H II regions. Nebulae without detected helium emission give robust y {sup +} upper limits. There are 5 RRL emission components with y {sup +} less than 0.04 and another 12 with upper limits below this value. These H II regions must have either a very low {sup 4}He abundance or contain a significant amount of neutral helium. The HRDS has 20 nebulae with carbon RRL emission but no helium emission at its sensitivity level. There is no correlation between the carbon RRL parameters and the 8 {mu}m mid-infrared morphology of these nebulae.
Wenger, Trey V.; Bania, T. M. [Astronomy Department, 725 Commonwealth Avenue, Boston University, Boston, MA 02215 (United States)] [Astronomy Department, 725 Commonwealth Avenue, Boston University, Boston, MA 02215 (United States); Balser, Dana S. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA, 22903-2475 (United States)] [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA, 22903-2475 (United States); Anderson, L. D. [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States)] [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States)
Background study for the pn-CCD detector of CERN Axion Solar Telescope
The CERN Axion Solar Telescope (CAST) experiment searches for axions from the Sun converted into photons with energies up to around 10 keV via the inverse Primakoff effect in the high magnetic field of a superconducting Large Hadron Collider (LHC) prototype magnet. A backside illuminated pn-CCD detector in conjunction with an X-ray mirror optics is one of the three detectors used in CAST to register the expected photon signal. Since this signal is very rare and different background components (environmental gamma radiation, cosmic rays, intrinsic radioactive impurities in the set-up, ...) entangle it, a detailed study of the detector background has been undertaken with the aim to understand and further reduce the background level of the detector. The analysis is based on measured data taken during the Phase I of CAST and on Monte Carlo simulations of different background components. This study will show that the observed background level (at a rate of (8.00+-0.07)10^-5 counts/cm^2/s/keV between 1 and 7 keV) seems to be dominated by the external gamma background due to usual activities at the experimental site, while radioactive impurities in the detector itself and cosmic neutrons could make just smaller contribution.
S. Cebrián; A. Rodríguez; M. Kuster; B. Beltrán; J. M. Carmona; H. Gómez; R. Hartmann; I. G. Irastorza; R. Kotthaus; G. Luzón; J. Morales; A. Ortiz de Solórzano; J. Ruz; L. Strüder; J. A. Villar
Telescoping in the context of symbolic summation in Maple - CECM
Apr 27, 2004 ... Symbolic summation is a vast research area in computer algebra. ...... hypergeometric terms, and 51 others used for accurate summation.
Current developments in oil shale research at the Laramie Energy Research Center. [Review of studies in 4 areas: concurrent gasification and retorting; high pressure retorting; abnormal heating rate of interior of large blocks of oil shale; and in-situ combustion
Current oil shale research being conducted at the Laramie Energy Research Center is many faceted, and some of the recent developments in these areas are presented. Concurrent gasification and retorting of oil shale where the effects of operating pressure and amounts of oxygen and water injection on quality and quantity of gas and oil produced is being studied. This work has resulted in off gas with heating values varying from 50 to 1,300 Btu/ft/sup 3/ and oil recovery of up to 80 vol percent of Fischer assay. The effects of retorting atmosphere, pressure, and external heating rate are being studied in a high pressure batch retort. Results from this work indicate that a nitrogen atmosphere decreases oil yield slightly while a hydrogen atmosphere increases the oil yield significantly. Large blocks of oil shale are being retorted in a 150-ton aboveground retort to study the abnormal heating rate of the interior of the blocks. This could be caused by an oxidation exotherm similar to that found in limited DTA studies. Some early results from the Rock Springs site 9 in-situ experiment are also presented. This is the fifth in-situ combustion experiment and is being performed in a 40-foot-thick oil shale bed having an average Fischer assay of 23 gallons per ton.
Jacobson, I.A. Jr.; Burwell, E.L.; Harak, A.E.; Long, A.; Wise, R.L.
The Integration of Telescopes, Instruments, and User Interfaces at KPNO and WIYN
. The telescopes at KPNO and WIYN use various methods to integrate the control of the telescopes and instruments with the user interfaces. These methods are described, showing the evolution from FORTH based serial connections to ethernet based RPC protocols and then to the WIYN message system and the GWC protocol in use at WIYN. The integration at WIYN is highlighted, including the operation of the message routers. 1. Introduction The six telescopes at Kitt Peak operated by NOAO for KPNO and WIYN use a variety of methods for control of the telescopes, sub-systems, and instruments. There is also a variety of user interfaces used with these systems. We first give an overview of these methods and then describe the integration of these systems. The KPNO telescopes discussed are: Mayall 4 meter, 2.1 meter, Coude Feed, 0.9 meter, and the Burrell-Schmidt. The WIYN telescope is a 3.5 meter telescope operated by NOAO for the WIYN Consortium (University of Wisconsin, Indiana University, Yale U...
B. Marshall; K. Gillies; J. Lewis
We perform aperture photometry and profile fitting on 419 globular cluster (GC) candidates with m{sub V} {<=} 23 mag identified in Hubble Space Telescope/Advanced Camera for Surveys BVI imaging, and estimate the effective radii of the clusters. We identify 85 previously known spectroscopically confirmed clusters, and newly identify 136 objects as good cluster candidates within the 3{sigma} color and size ranges defined by the spectroscopically confirmed clusters, yielding a total of 221 probable GCs. The luminosity function peak for the 221 probable GCs with estimated total dereddening applied is V {approx} (20.26 {+-} 0.13) mag, corresponding to a distance of {approx}3.7 {+-} 0.3 Mpc. The blue and red GC candidates, and the metal-rich and metal-poor spectroscopically confirmed clusters, respectively, are similar in half-light radius. Red confirmed clusters are about 6% larger in median half-light radius than blue confirmed clusters, and red and blue good GC candidates are nearly identical in half-light radius. The total population of confirmed and 'good' candidates shows an increase in half-light radius as a function of galactocentric distance.
Nantais, Julie B. [Departamento de Astronomia, Universidad de Concepcion Av. Esteban Iturra s/n Barrio Universitario Casilla 160-C Concepcion (Chile); Huchra, John P.; Zezas, Andreas; Gazeas, Kosmas; Strader, Jay [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
Position-sensitive detector for the 6-meter optical telescope
The Position-Sensitive Detector (PSD) for photometrical and spectral observation on the 6-meter optical telescope of the Special Astrophysical Observatory (Russia) is described. The PSD consists of a position-sensitive tube, amplifiers of output signals, analog-to-digital converters (ADC) and a digital logic plate, which produces a signal for ADC start and an external strob pulse for reading information by registration system. If necessary, the thermoelectric cooler can be used. The position-sensitive tube has the following main elements: a photocathode, electrodes of inverting optics, a block of microchannel plates (MCP) and a position-sensitive collector of quadrant type. The main parameters of the PSD are the diameter of the sensitive surface is 25 mm, the spatial resolution is better than 100 (\\mu)m in the centre and a little worse on the periphery; the dead time is near 0.5 (\\mu)s; the detection quantum efficiency is defined by the photocathode and it is not less than 0.1, as a rule; dark current is about hundreds of cps, or less, when cooling. PSD spectral sensitivity depends on the type of photocathode and input window material. We use a multialkali photocathode and a fiber or UV-glass, which gives the short- wave cut of 360 nm or 250 nm, respectively.
V. Debur; T. Arkhipova; G. Beskin; V. Plokhotnichenko; M. Pakhomov; M. Smirnova; A. Solin
The Burst Alert Telescope (BAT) on the Swift MIDEX Mission
The Burst Alert Telescope (BAT) is one of 3 instruments on the Swift MIDEX spacecraft to study gamma-ray bursts (GRBs). The BAT first detects the GRB and localizes the burst direction to an accuracy of 1-4 arcmin within 20 sec after the start of the event. The GRB trigger initiates an autonomous spacecraft slew to point the two narrow field-of-view (FOV) instruments at the burst location within 20-70 sec so to make follow-up x-ray and optical observations. The BAT is a wide-FOV, coded-aperture instrument with a CdZnTe detector plane. The detector plane is composed of 32,768 pieces of CdZnTe (4x4x2mm), and the coded-aperture mask is composed of approximately 52,000 pieces of lead (5x5x1mm) with a 1-m separation between mask and detector plane. The BAT operates over the 15-150 keV energy range with approximately 7 keV resolution, a sensitivity of approximately 10E-8 erg*cm^-2*s^-1, and a 1.4 sr (half-coded) FOV. We expect to detect >100 GRBs/yr for a 2-year mission. The BAT also performs an all-sky hard x-ray survey with a sensitivity of approximately 2 mCrab (systematic limit) and it serves as a hard x-ray transient monitor.
S. D. Barthelmy; L. M. Barbier; J. R. Cummings; E. E. Fenimore; N. Gehrels; D. Hullinger; H. A. Krimm; C. B. Markwardt; D. M. Palmer; A. Parsons; G. Sato; M. Suzuki; T. Takahashi; M. Tashiro; J. Tueller
Calibration systems and methods for the ANTARES neutrino telescope
The ANTARES neutrino telescope is currently being constructed in the Mediterranean Sea. The complete detector will consist of 12 strings, supplemented by an additional instrumentation line. Nine strings are at present deployed of which five are already connected to the shore and operating. Each string is equipped with 75 Optical Modules (OMs) housing the photomultipliers to detect the Cherenkov light induced by the charged particles produced in neutrino reactions. An accurate measurement of the Cherenkov photon arrival times as well as the positions and orientations of the OMs is required for a precise reconstruction of the direction of the detected neutrinos. For this purpose the ANTARES detector is provided with several system s to facilitate the calibration of the detector. The time calibration is performed using light pulses emitted from LED and laser devices. The positioning is done via acoustic triangulation using hydrophones. Additionally, local tilt angles and the orientations of the modules are measured with a set of tiltmeters and compasses. In this paper, it is demonstrated that the ANTARES time and alignment calibration systems operate successfully in situ. In particular, it is shown that the ANTARES read-out electronics is capable of reaching a sub-nanosecond time resolution.
Felix Fehr; for the ANTARES Collaboration
Cosmic String constraints from WMAP and the South Pole Telescope
The predictions of the inflationary LCDM paradigm match today's high-precision measurements of the cosmic microwave background anisotropy extremely well. The same data put tight limits on other sources of anisotropy. Cosmic strings are a particularly interesting alternate source to constrain. Strings are topological defects, remnants of inflationary-era physics that persist after the big bang. They are formed in a variety of models of inflation, including string theory models such as brane inflation. We assume a "Nambu-Goto" model for strings, approximated by a collection of unconnected segments with zero width, and show that measurements of temperature anisotropy by the South Pole Telescope break a parameter degeneracy in the WMAP data, permitting us to place a strong upper limit on the possible string contribution to the CMB anisotropy: the power sourced by zero-width strings must be <1.75% (95% CL) of the total or the string tension Gmu <1.7x10^{-7}. These limits imply that the best hope for detecting strings in the CMB will come from B-mode polarization measurements at arcminute scales rather than the degree scale measurements pursued for gravitational wave detection.
Cora Dvorkin; Mark Wyman; Wayne Hu
Results of a statistical analysis of solar granulation are presented. A data set of 36 images of a quiet-Sun area on the solar disk center was used. The data were obtained with the 1.6 m clear aperture New Solar Telescope at Big Bear Solar Observatory and with a broadband filter centered at the TiO (705.7 nm) spectral line. The very high spatial resolution of the data (diffraction limit of 77 km and pixel scale of 0.''0375) augmented by the very high image contrast (15.5% {+-} 0.6%) allowed us to detect for the first time a distinct subpopulation of mini-granular structures. These structures are dominant on spatial scales below 600 km. Their size is distributed as a power law with an index of -1.8 (which is close to the Kolmogorov's -5/3 law) and no predominant scale. The regular granules display a Gaussian (normal) size distribution with a mean diameter of 1050 km. Mini-granular structures contribute significantly to the total granular area. They are predominantly confined to the wide dark lanes between regular granules and often form chains and clusters, but different from magnetic bright points. A multi-fractality test reveals that the structures smaller than 600 km represent a multi-fractal, whereas on larger scales the granulation pattern shows no multi-fractality and can be considered as a Gaussian random field. The origin, properties, and role of the population of mini-granular structures in the solar magnetoconvection are yet to be explored.
Abramenko, V. I.; Yurchyshyn, V. B.; Goode, P. R. [Big Bear Solar Observatory, 40386 N. Shore Lane, Big Bear City, CA 92314 (United States); Kitiashvili, I. N.; Kosovichev, A. G. [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)
Limits on Large Extra Dimensions Based on Observations of Neutron Stars with the Fermi-LAT
We present limits for the compactification scale in the theory of Large Extra Dimensions (LED) proposed by Arkani-Hamed, Dimopoulos, and Dvali. We use 11 months of data from the Fermi Large Area Telescope (Fermi-LAT) to set gamma ray flux limits for 6 gamma-ray faint neutron stars (NS). To set limits on LED we use the model of Hannestad and Raffelt (HR) that calculates the Kaluza-Klein (KK) graviton production in supernova cores and the large fraction subsequently gravitationally bound around the resulting NS. The predicted decay of the bound KK gravitons to {gamma}{gamma} should contribute to the flux from NSs. Considering 2 to 7 extra dimensions of the same size in the context of the HR model, we use Monte Carlo techniques to calculate the expected differential flux of gamma-rays arising from these KK gravitons, including the effects of the age of the NS, graviton orbit, and absorption of gamma-rays in the magnetosphere of the NS. We compare our Monte Carlo-based differential flux to the experimental differential flux using maximum likelihood techniques to obtain our limits on LED. Our limits are more restrictive than past EGRET-based optimistic limits that do not include these important corrections. Additionally, our limits are more stringent than LHC based limits for 3 or fewer LED, and comparable for 4 LED. We conclude that if the effective Planck scale is around a TeV, then for 2 or 3 LED the compactification topology must be more complicated than a torus.
Ajello, M.; /SLAC /KIPAC, Menlo Park; Baldini, L.; /INFN, Pisa; Barbiellini, G.; /INFN, Trieste /Trieste U.; Bastieri, D.; /INFN, Padua /Padua U.; Bechtol, K.; /SLAC /KIPAC, Menlo Park; Bellazzini, R.; /INFN, Pisa; Berenji, B.; /SLAC /KIPAC, Menlo Park; Bloom, E.D.; /SLAC /KIPAC, Menlo Park; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, A.W.; /SLAC /KIPAC, Menlo Park; Bregeon, J.; /INFN, Pisa; Brigida, M.; /Bari Polytechnic /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Buehler, R.; /SLAC /KIPAC, Menlo Park; Buson, S.; /INFN, Padua /Padua U.; Caliandro, G.A.; /CSIC, Catalunya; Cameron, R.A.; /SLAC /KIPAC, Menlo Park; Caraveo, P.A.; /Brera Observ.; Casandjian, J.M.; /AIM, Saclay; Cecchi, C.; /INFN, Perugia /Perugia U.; Charles, E.; /SLAC /KIPAC, Menlo Park /Naval Research Lab, Wash., D.C. /SLAC /KIPAC, Menlo Park /ASDC, Frascati /Perugia U. /SLAC /KIPAC, Menlo Park /Montpellier U. /Stockholm U. /Stockholm U., OKC /Royal Swedish Acad. Sci. /ASDC, Frascati /Udine U. /INFN, Trieste /Bari Polytechnic /INFN, Bari /Naval Research Lab, Wash., D.C. /SLAC /KIPAC, Menlo Park /SLAC /KIPAC, Menlo Park /SLAC /KIPAC, Menlo Park /SLAC /KIPAC, Menlo Park /Bari Polytechnic /INFN, Bari /Ecole Polytechnique /NASA, Goddard /Hiroshima U. /Bari Polytechnic /INFN, Bari /INFN, Bari /ASDC, Frascati /INFN, Perugia /Perugia U. /Bari Polytechnic /INFN, Bari /Bari Polytechnic /INFN, Bari /Bologna Observ. /SLAC /KIPAC, Menlo Park /SLAC /KIPAC, Menlo Park /SLAC /KIPAC, Menlo Park /AIM, Saclay /Alabama U., Huntsville /INFN, Padua; /more authors..
The Space Infrared Interferometric Telescope (SPIRIT): High-resolution imaging and spectroscopy in the far-infrared
We report results of a recently-completed pre-Formulation Phase study of SPIRIT, a candidate NASA Origins Probe mission. SPIRIT is a spatial and spectral interferometer with an operating wavelength range 25 - 400 microns. SPIRIT will provide sub-arcsecond resolution images and spectra with resolution R = 3000 in a 1 arcmin field of view to accomplish three primary scientific objectives: (1) Learn how planetary systems form from protostellar disks, and how they acquire their inhomogeneous composition; (2) characterize the family of extrasolar planetary systems by imaging the structure in debris disks to understand how and where planets of different types form; and (3) learn how high-redshift galaxies formed and merged to form the present-day population of galaxies. Observations with SPIRIT will be complementary to those of the James Webb Space Telescope and the ground-based Atacama Large Millimeter Array. All three observatories could be operational contemporaneously.
David Leisawitz; Charles Baker; Amy Barger; Dominic Benford; Andrew Blain; Rob Boyle; Richard Broderick; Jason Budinoff; John Carpenter; Richard Caverly; Phil Chen; Steve Cooley; Christine Cottingham; Julie Crooke; Dave DiPietro; Mike DiPirro; Michael Femiano; Art Ferrer; Jacqueline Fischer; Jonathan P. Gardner; Lou Hallock; Kenny Harris; Kate Hartman; Martin Harwit; Lynne Hillenbrand; Tupper Hyde; Drew Jones; Jim Kellogg; Alan Kogut; Marc Kuchner; Bill Lawson; Javier Lecha; Maria Lecha; Amy Mainzer; Jim Mannion; Anthony Martino; Paul Mason; John Mather; Gibran McDonald; Rick Mills; Lee Mundy; Stan Ollendorf; Joe Pellicciotti; Dave Quinn; Kirk Rhee; Stephen Rinehart; Tim Sauerwine; Robert Silverberg; Terry Smith; Gordon Stacey; H. Philip Stahl; Johannes Staguhn; Steve Tompkins; June Tveekrem; Sheila Wall; Mark Wilson
We compare cosmic microwave background lensing convergence maps derived from South Pole Telescope (SPT) data with galaxy survey data from the Blanco Cosmology Survey, WISE, and a new large Spitzer/IRAC field designed to overlap with the SPT survey. Using optical and infrared catalogs covering between 17 and 68 deg{sup 2} of sky, we detect a correlation between the SPT convergence maps and each of the galaxy density maps at >4{sigma}, with zero correlation robustly ruled out in all cases. The amplitude and shape of the cross-power spectra are in good agreement with theoretical expectations and the measured galaxy bias is consistent with previous work. The detections reported here utilize a small fraction of the full 2500 deg{sup 2} SPT survey data and serve as both a proof of principle of the technique and an illustration of the potential of this emerging cosmological probe.
Bleem, L. E.; Becker, M. R.; Benson, B. A.; Carlstrom, J. E.; Chang, C. L.; Crawford, T. M.; Crites, A. T. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Van Engelen, A.; Holder, G. P.; De Haan, T.; Dobbs, M. A. [Department of Physics, McGill University, 3600 Rue University, Montreal, Quebec H3A 2T8 (Canada); Aird, K. A. [University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Armstrong, R. [National Center for Supercomputing Applications, University of Illinois, 1205 West Clark Street, Urbana, IL 61801 (United States); Ashby, M. L. N. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Biesiadzinski, T. [Department of Physics, University of Michigan, 450 Church Street, Ann Arbor, MI 48109 (United States); Brodwin, M. [Department of Physics and Astronomy, University of Missouri, 5110 Rockhill Road, Kansas City, MO 64110 (United States); Busha, M. T. [Institute for Theoretical Physics, University of Zuerich, Zuerich (Switzerland); Cho, H. M. [NIST Quantum Devices Group, 325 Broadway, Mailcode 817.03, Boulder, CO 80305 (United States); Desai, S. [Department of Physics, Ludwig-Maximilians-Universitaet, Scheinerstr. 1, 81679 Muenchen (Germany); Dore, O. [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, MS 249-17, 1216 East California Blvd., Pasadena, CA 91125 (United States); and others
Strategic Focus Areas
Focus Areas Lockheed Martin on behalf of Sandia National Laboratories will consider grant requests that best support the Corporation's strategic focus areas and reflect effective...
Green Bank Telescope Studies of Giant Pulses from Millisecond Pulsars
We have conducted a search for giant pulses from four millisecond pulsars using the 100m Green Bank Telescope. Coherently dedispersed time-series from PSR J0218+4232 were found to contain giant pulses of very short intrinsic duration whose energies follow power-law statistics. The giant pulses are in phase with the two minima of the radio integrated pulse profile but are phase aligned with the peaks of the X-ray profile. Historically, individual pulses more than 10-20 times the mean pulse energy have been deemed to be ``giant pulses''. As only 4 of the 155 pulses had energies greater than 10 times the mean pulse-energy, we argue the emission mechanism responsible for giant pulses should instead be defined through: (a) intrinsic timescales of microsecond or nanosecond duration; (b) power-law energy statistics; and (c) emission occurring in narrow phase-windows coincident with the phase windows of non-thermal X-ray emission. Four short-duration pulses with giant-pulse characteristics were also observed from PSR B1957+20. As the inferred magnetic fields at the light cylinders of the millisecond pulsars that emit giant pulses are all very high, this parameter has previously been considered to be an indicator of giant pulse emissivity. However, the frequency of giant pulse emission from PSR~B1957+20 is significantly lower than for other millisecond pulsars that have similar magnetic fields at their light cylinders. This suggests that the inferred magnetic field at the light cylinder is a poor indicator of the rate of emission of giant pulses.
H. S. Knight; M. Bailes; R. N. Manchester; S. M. Ord; B. A. Jacoby
We present images of 29 post-starburst quasars (PSQs) from a Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) Wide Field Channel Snapshot program. These broadlined active galactic nuclei (AGNs) possess the spectral signatures of massive (M{sub burst} {approx} 10{sup 10} M{sub sun}), moderate-aged stellar populations (hundreds of Myr). Thus, their composite nature provides insight into the AGN-starburst connection. We measure quasar-to-host galaxy light contributions via semi-automated two-dimensional light profile fits of point-spread-function-subtracted images. We examine the host morphologies and model the separate bulge and disk components. The HST/ACS-F606W images reveal an equal number of spiral (13/29) and early-type (13/29) hosts, with the remaining three hosts having indeterminate classifications. AGNs hosted by early-type galaxies have on average greater luminosity than those hosted by spiral galaxies. Disturbances such as tidal tails, shells, star-forming knots, and asymmetries are seen as signposts of interaction/merger activity. Disturbances like these were found in 17 of the 29 objects and are evenly distributed among early-type and spiral galaxies. Two of these systems are clearly merging with their companions. Compared to other AGNs of similar luminosity and redshift, these PSQs have a higher fraction of early-type hosts and disturbances. Our most luminous objects with disturbed early-type host galaxies appear to be consistent with merger products. Thus, these luminous galaxies may represent a phase in an evolutionary scenario for merger-driven activity. Our less luminous objects appear to be consistent with Seyfert galaxies not requiring triggering by major mergers. Many of these Seyferts are barred spiral galaxies.
Cales, S. L.; Brotherton, M. S.; Shang Zhaohui [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Bennert, Vardha Nicola [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Canalizo, G. [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Stoll, R. [Department of Astronomy, Ohio State University, Columbus, OH 43210 (United States); Ganguly, R. [Department of Computer Science, Engineering, and Physics, University of Michigan-Flint, Flint, MI 48502 (United States); Vanden Berk, D. [Department of Physics, Saint Vincent College, Latrobe, PA 15650 (United States); Paul, C. [Physics Department, University of California, Davis, CA 95616 (United States); Diamond-Stanic, A., 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: firstname.lastname@example.com, E-mail: firstname.lastname@example.com, E-mail: email@example.com, E-mail: email@example.com, E-mail: firstname.lastname@example.com, E-mail: email@example.com [Center for Astrophysics and Space Sciences, University of California, San Diego, La Jolla, CA 92093 (United States)
User Interface for the Control of the Gemini Telescopes S. S. Smith and K. Gillies
on the science detectors is a primary goal. Keywords: Gemini Telescope Control User Interface Tcl/Tk EPICS 1 are being built using Tcl/Tk 1 and are implemented to follow the ESO Graphical User Interface Common
detectors is a primary goal. Keywords: Gemini Telescope Control User Interface Tcl/Tk EPICS 1. INTRODUCTION software to cover the requirements of both. Applications are being built using Tcl/Tk1 and are implemented
Thin optic surface analysis for high resolution X-ray telescopes
The art of glass developed throughout the years has covered artifacts ranging from crude ornaments to high precision optics used in flat panel displays, hard disk drives, and x-ray telescopes. Methods for manufacturing ...
Akilian, Mireille
We have searched 75 unidentified radio sources selected from the NRAO VLA Sky Survey catalog for the presence of rapidly spinning pulsars and short, dispersed radio bursts. The sources are radio bright, have no identifications or optical source coincidences, are more than 5% linearly polarized, and are spatially unresolved in the catalog. If these sources are fast-spinning pulsars (e.g., sub-millisecond pulsars), previous large-scale pulsar surveys may have missed detection due to instrumental and computational limitations, eclipsing effects, or diffractive scintillation. The discovery of a sub-millisecond pulsar would significantly constrain the neutron star equation of state and would have implications for models predicting a rapid slowdown of highly recycled X-ray pulsars to millisecond periods from, e.g., accretion disk decoupling. These same sources were previously searched unsuccessfully for pulsations at 610 MHz with the Lovell Telescope at Jodrell Bank. This new search was conducted at a different epoch with a new 800 MHz backend on the NRAO 43 m Telescope at a center frequency of 1200 MHz. Our search was sensitive to sub-millisecond pulsars in highly accelerated binary systems and to short transient pulses. No periodic or transient signals were detected from any of the target sources. We conclude that diffractive scintillation, dispersive smearing, and binary acceleration are unlikely to have prevented detection of the large majority of the sources if they are pulsars, though we cannot rule out eclipsing, nulling or intermittent emission, or radio interference as possible factors for some non-detections. Other (speculative) possibilities for what these sources might include radio-emitting magnetic cataclysmic variables or older pulsars with aligned magnetic and spin axes.
Schmidt, Deborah; Crawford, Fronefield; Gilpin, Claire [Department of Physics and Astronomy, Franklin and Marshall College, P.O. Box 3003, Lancaster, PA 17604 (United States); Langston, Glen [National Radio Astronomy Observatory, P.O. Box 2, Green Bank, WV 24944 (United States)
Watching an uniformly moving source of light using a telescope and a frequency-meter
We propose a scenario that involves a stationary observer who detects a point like source of light moving with constant velocity at a constant altitude, using a telescope and a frequency-meter. We derive a formula for the angular velocity at which we should rotate the axis of the telescope and a formula that relates the proper period at which the source emits successive wave crests and the proper period at which the stationary observer receives them
Bernhard Rothenstein; Ioan Damian
Manhattan Project: Tech Area Gallery
Office of Scientific and Technical Information (OSTI)
TECH AREA GALLERY (LARGE) TECH AREA GALLERY (LARGE) Los Alamos: The Laboratory Resources > Photo Gallery All of the photographs below are of the "Tech Area" at Los Alamos during or shortly after the wartime years. If this page is taking a long time to load, click here for a photo gallery with smaller versions of the same images. There is a map of the Tech Area at the top and again at the bottom. The first image below is courtesy the Los Alamos National Laboratory. All of the other photographs are reproduced from Edith C. Truslow, with Kasha V. Thayer, ed., Manhattan Engineer District: Nonscientific Aspects of Los Alamos Project Y, 1942 through 1946 (Los Alamos, NM: Manhattan Engineer District, ca. 1946; first printed by Los Alamos Scientific Laboratory as LA-5200, March 1973; reprinted in 1997 by the Los Alamos Historical Society). This is a reprint of an unpublished volume originally written in 1946 by 2nd Lieutenant Edith C. Truslow, a member of the Women's Army Corps, as a contribution to the Manhattan Engineer District History.
How China utilizes biogas in rural areas
An outline is presented of how China utilizes biogas in rural areas. Already, 7,140,000 small biogas digesters have been built. Sichuan province has 4,160,000 digesters including about 20,000 large digesters which operate diesel engines to generate electricity. This is seen as the key area for further research and development. In rural areas, biogas is used principally for cooking and to power stationary units such as grinding mills, electric generators and crop driers.
Ji, M.
SciTech Connect: "smart grid"
Large Area Telescope Constraints on the Gamma-ray Opacity of the Universe Citation Details In-Document Search Title: Fermi Large Area Telescope Constraints on the Gamma-ray Opacity...
Discovery of Very High Energy Gamma-Rays from the Distant Flat Spectrum Radio Quasar 3C 279 with the MAGIC Telescope
The quasar 3C 279 is one of the best-studied flat spectrum radio quasars. It is located at a comparatively large redshift of z=0.536: E>100 GeV observations of such distant sources were until recently impossible both due to the expected steep energy spectrum and the expected attenuation of the gamma-rays by the extragalactic background light. Here we present results on the observation of 3C 279 with the MAGIC telescope in early 2006. We report the detection of a significant very high energy gamma-ray signal in the MAGIC energy range on the observation night of 2006 February 23.
Masahiro Teshima; Elisa Prandini; Rudolf Bock; Manel Errando; Daniel Kranich; Pratik Majumdar; Daniel Mazin; Elina Lindfors; Eckart Lorenz; Mose Mariotti; Villi Scalzotto; Robert Wagner
Large-Scale Hydropower
Energy.gov (U.S. Department of Energy (DOE))
Large-scale hydropower plants are generally developed to produce electricity for government or electric utility projects. These plants are more than 30 MW in size, and there is more than 80,000 MW...
Using the H I emission/absorption method, we resolve the kinematic distance ambiguity and derive distances for 149 of 182 (82%) H II regions discovered by the Green Bank Telescope H II Region Discovery Survey (GBT HRDS). The HRDS is an X-band (9 GHz, 3 cm) GBT survey of 448 previously unknown H II regions in radio recombination line and radio continuum emission. Here, we focus on HRDS sources from 67 Degree-Sign {>=} l {>=} 18 Degree-Sign , where kinematic distances are more reliable. The 25 HRDS sources in this zone that have negative recombination line velocities are unambiguously beyond the orbit of the Sun, up to 20 kpc distant. They are the most distant H II regions yet discovered. We find that 61% of HRDS sources are located at the far distance, 31% at the tangent-point distance, and only 7% at the near distance. 'Bubble' H II regions are not preferentially located at the near distance (as was assumed previously) but average 10 kpc from the Sun. The HRDS nebulae, when combined with a large sample of H II regions with previously known distances, show evidence of spiral structure in two circular arc segments of mean Galactocentric radii of 4.25 and 6.0 kpc. We perform a thorough uncertainty analysis to analyze the effect of using different rotation curves, streaming motions, and a change to the solar circular rotation speed. The median distance uncertainty for our sample of H II regions is only 0.5 kpc, or 5%. This is significantly less than the median difference between the near and far kinematic distances, 6 kpc. The basic Galactic structure results are unchanged after considering these sources of uncertainty.
Anderson, L. D. [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States); Bania, T. M. [Institute for Astrophysical Research, Department of Astronomy, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States); Balser, Dana S. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475 (United States); Rood, Robert T., E-mail: email@example.com [Astronomy Department, University of Virginia, P.O. Box 3818, Charlottesville, VA 22903-0818 (United States)
Hubble Space Telescope Fine Guidance Sensor Parallaxes of Galactic Cepheid Variable Stars: Period-Luminosity Relations
(abridged) We present new absolute trigonometric parallaxes and relative proper motions for nine Galactic Cepheid variable stars: l Car, zeta Gem, beta Dor, W Sgr, X Sgr, Y Sgr, FF Aql, T Vul, and RT Aur. We obtain these results with astrometric data from Fine Guidance Sensor 1r, a white-light interferometer on Hubble Space Telescope. We find absolute parallaxes with an average sigma_pi/pi = 8%. Two stars (FF Aql and W Sgr) required the inclusion of binary astrometric perturbations, providing Cepheid mass estimates. With these parallaxes we compute absolute magnitudes in V, I, K, and Wesenheit W_{VI} bandpasses corrected for interstellar extinction and Lutz-Kelker-Hanson bias. Adding our previous absolute magnitude determination for delta Cep, we construct Period-Luminosity relations for ten Galactic Cepheids. We compare our new Period-Luminosity relations with those adopted by several recent investigations, including the Freedman and Sandage H_0 projects. Adopting our Period-Luminosity relationship would tend to increase the Sandage H_$ value, but leave the Freedman H_0 unchanged. Comparing our Galactic Cepheid PLR with those derived from LMC Cepheids, we find the slopes for K and W_{VI} identical in the two galaxies within their respective errors. Our data lead to a W_{VI} distance modulus for the Large Magellanic Cloud, m-M = 18.50\\pm0.03, uncorrected for any metallicity effects. Applying recently derived metalllcity corrections yields a corrected LMC distance modulus of (m-M)_0=18.40\\pm0.05. Comparing our Period-Luminosity relationship to solar-metallicity Cepheids in NGC 4258 results in a distance modulus, 29.28 \\pm 0.08, which agrees with that derived from maser studies.
G. Fritz Benedict; Barbara E. McArthur; Michael W. Feast; Thomas G. Barnes; Thomas E. Harrison; Richard J. Patterson; John W. Menzies; Jacob L. Bean; Wendy L. Freedman
Rail Access Modes and Catchment Areas for the BART System
parking supplies), ridership (e.g. , rail modalsplits), andbuses, cable cars, light rail transit, trams,andferryresidents in the area commute rail in large part becausemany
Cervero, Robert; Round, Alfred; Goldman, Todd; Wu, Kang-Li
Division/ Interest Area Information
Learn more about Divisions and Interest areas. Division/ Interest Area Information Membership Information achievement application award Awards distinguished division Divisions fats job Join lipid lipids Member member get a member Membership memori
DOE Designates Southwest Area and Mid-Atlantic Area National...
Designates Southwest Area and Mid-Atlantic Area National Interest Electric Transmission Corridors October 2, 2007 DOE Designates Southwest Area and Mid-Atlantic Area National...
Designates Southwest Area and Mid-Atlantic Area National Interest Electric Transmission Corridors DOE Designates Southwest Area and Mid-Atlantic Area National Interest Electric...
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Brady Hot Springs Geothermal Area Brady Hot Springs Geothermal Area Northwest Basin and Range Geothermal Region MW K Coso Geothermal Area Coso Geothermal Area Walker Lane...
The drive system of the Major Atmospheric Gamma-ray Imaging Cherenkov Telescope
The MAGIC telescope is an imaging atmospheric Cherenkov telescope, designed to observe very high energy gamma-rays while achieving a low energy threshold. One of the key science goals is fast follow-up of the enigmatic and short lived gamma-ray bursts. The drive system for the telescope has to meet two basic demands: (1) During normal observations, the 72-ton telescope has to be positioned accurately, and has to track a given sky position with high precision at a typical rotational speed in the order of one revolution per day. (2) For successfully observing GRB prompt emission and afterglows, it has to be powerful enough to position to an arbitrary point on the sky within a few ten seconds and commence normal tracking immediately thereafter. To meet these requirements, the implementation and realization of the drive system relies strongly on standard industry components to ensure robustness and reliability. In this paper, we describe the mechanical setup, the drive control and the calibration of the pointing, as well as present measurements of the accuracy of the system. We show that the drive system is mechanically able to operate the motors with an accuracy even better than the feedback values from the axes. In the context of future projects, envisaging telescope arrays comprising about 100 individual instruments, the robustness and scalability of the concept is emphasized.
T. Bretz; D. Dorner; R. M. Wagner; P. Sawallisch
Analysis of large urban fires
Fires in urban areas caused by a nuclear burst are analyzed as a first step towards determining their smoke-generation chacteristics, which may have grave implications for global-scale climatic consequences. A chain of events and their component processes which would follow a nuclear attack are described. A numerical code is currently being developed to calculate ultimately the smoke production rate for a given attack scenario. Available models for most of the processes are incorporated into the code. Sample calculations of urban fire-development history performed in the code for an idealized uniform city are presented. Preliminary results indicate the importance of the wind, thermal radiation transmission, fuel distributions, and ignition thresholds on the urban fire spread characteristics. Future plans are to improve the existing models and develop new ones to characterize smoke production from large urban fires. 21 references, 18 figures.
Kang, S.W.; Reitter, T.A.; Takata, A.N.
RHIC | New Areas of Physics
A New Area of Physics A New Area of Physics RHIC has created a new state of hot, dense matter out of the quarks and gluons that are the basic particles of atomic nuclei, but it is a state quite different and even more remarkable than had been predicted. Instead of behaving like a gas of free quarks and gluons, as was expected, the matter created in RHIC's heavy ion collisions is more like a liquid. Quarks Gluons and quarks Ions Ions about to collide Impact Just after collision Perfect Liquid The "perfect" liquid hot matter Hot Nuclear Matter A review article in the journal Science describes groundbreaking discoveries that have emerged from RHIC, synergies with the heavy-ion program at the Large Hadron Collider, and the compelling questions that will drive this research forward on both sides of the Atlantic.
Large Occlusion Stereo
A method for solving the stereo matching problem in the presence of large occlusion is presented. A data structure—the disparity space image—is defined to facilitate the description of the effects of occlusion on the stereo matching process ... Keywords: disparity-space, dynamic-programming stereo, occlusion, stereo
Aaron F. Bobick; Stephen S. Intille
Composting Large Animal Carcasses
Disposing of large animal carcasses can be a problem for agricultural producers. Composting is a simple, low-cost method that yields a useful product that can be used as fertilizer. In this publication you'll learn the basics of composting, how to build and maintain a compost pile, tools you will need, and how to use the finished compost.
Auvermann, Brent W.; Mukhtar, Saqib; Heflin, Kevin
Perspectives of a mid-rapidity dimuon program at the RHIC: a novel and compact muon telescope detector
Telescope Detector L. Ruan Brookhaven National Laboratory,Connecticut 06520 Z. Xu Brookhaven National Laboratory,York 11973 K. Asselta Brookhaven National Laboratory, Upton,
Ruan, L.
South Pole Telescope helps Argonne scientists study earliest ages of the
Related Content Related Content Employee Spotlight: Clarence Chang South Pole Telescope helps Argonne scientists study earliest ages of the universe By Louise Lerner * October 28, 2013 Tweet EmailPrint For physicist Clarence Chang at the U.S. Department of Energy's (DOE) Argonne National Laboratory, looking backward in time to the earliest ages of the universe is all in a day's work. Chang helped design and operate part of the South Pole Telescope, a project that aims a giant telescope at the night sky to track tiny bits of radiation that are still traveling across the universe from the period just after it was born. "Basically, what we're looking at is the afterglow light of the Big Bang," Chang said. In the wake of the Big Bang, all the matter in the universe was just hot,
The High-Resolution Lightweight Telescope for the EUV (HiLiTE)
The High-resolution Lightweight Telescope for the EUV (HiLiTE) is a Cassegrain telescope that will be made entirely of Silicon Carbide (SiC), optical substrates and metering structure alike. Using multilayer coatings, this instrument will be tuned to operate at the 465 {angstrom} Ne VII emission line, formed in solar transition region plasma at {approx}500,000 K. HiLiTE will have an aperture of 30 cm, angular resolution of {approx}0.2 arc seconds and operate at a cadence of {approx}5 seconds or less, having a mass that is about 1/4 that of one of the 20 cm aperture telescopes on the Atmospheric Imaging Assembly (AIA) instrument aboard NASA's Solar Dynamics Observatory (SDO). This new instrument technology thus serves as a path finder to a post-AIA, Explorer-class missions.
Martinez-Galarce, D S; Boerner, P; Soufli, R; De Pontieu, B; Katz, N; Title, A; Gullikson, E M; Robinson, J C; Baker, S L
Metrology for x-ray telescope mirrors in a vertical configuration
Mirrors used in x-ray telescope systems for observations outside of the earth`s atmosphere are usually made of several thin nested shells, each formed by a pair of paraboloidal and hyperboloidal surfaces. The thin shells are very susceptible to self-weight deflection caused by gravity and are nearly impossible to test by conventional interferometric techniques. The metrology requirements for these mirrors are extremely challenging. This paper presents a prototype of a Vertical Scanning Long Trace Profiler (VSLTP) which is optimized to measure the surface figure of x-ray telescope mirrors in a vertical orientation. The optical system of the VSLTP is described. Experimental results from measurements on an x-ray telescope mandrel and tests of the accuracy and repeatability of the prototype VSLTP are presented. The prototype instrument has achieved a height measurement accuracy of about 50 nanometers with a repeatability of better than 20 nanometers, and a slope measurement accuracy of about 1 microradian.
Li, Haizhang; Li, Xiaodan; Grindel, M.W.
Autonomous Observing and Control Systems for PAIRITEL, a 1.3m Infrared Imaging Telescope
The Peters Automated Infrared Imaging Telescope (PAIRITEL) is the first meter-class telescope operating as a fully robotic IR imaging system. Dedicated in October 2004, PAIRITEL began regular observations in mid-December 2004 as part of a 1.5 year commissioning period. The system was designed to respond without human intervention to new gamma-ray burst transients: this milestone was finally reached on November 9, 2005 but the telescope had a number of semi-automated sub-10 minute responses throughout early commissioning. When not operating in Target of Opportunity mode, PAIRITEL performs a number of queue scheduled transient monitoring campaigns. To achieve this level of automation, we have developed communicating tools to connect the various sub-systems: an intelligent queue scheduling database, run-time configurable observation sequence software, a data reduction pipeline, and a master state machine which monitors and controls all functions within and affecting the observatory.
J. S. Bloom; Dan L. Starr; Cullen H. Blake; M. F. Skrutskie; Emilio E. Falco
Frozen Telescope Looks to Ends of the Earth for Answers | Department of
Frozen Telescope Looks to Ends of the Earth for Answers Frozen Telescope Looks to Ends of the Earth for Answers Frozen Telescope Looks to Ends of the Earth for Answers May 3, 2012 - 2:20pm Addthis Researchers drilled holes in the ice to a depth of almost 1.5 miles, and lowered 60 basketball-sized detectors called digital optical modules (DOMs) into each of the 86 holes. They then had to pull cables to connect the sensors to IceCube Lab's servers in order to collect data. | Photo courtesy of the National Science Foundation Researchers drilled holes in the ice to a depth of almost 1.5 miles, and lowered 60 basketball-sized detectors called digital optical modules (DOMs) into each of the 86 holes. They then had to pull cables to connect the sensors to IceCube Lab's servers in order to collect data. | Photo
Hubble Space Telescope Imaging of the Circumnuclear Environments of the CfA Seyfert Galaxies: Nuclear Spirals and Fueling
We present archival Hubble Space Telescope images of the nuclear regions of 43 of the 46 Seyfert galaxies found in the volume-limited, spectroscopically-complete CfA Redshift Survey sample. Using an improved method of image contrast enhancement, we create detailed high-quality structure maps that allow us to study the distributions of dust, star clusters, and emission-line gas in the circumnuclear regions (100-1000 pc scales) and in the associated host galaxy. Essentially all of these Seyfert galaxies have circumnuclear dust structures with morphologies ranging from grand-design two-armed spirals to chaotic dusty disks. In most Seyferts there is a clear physical connection between the nuclear dust spirals on hundreds of parsec scales and large-scale bars and spiral arms in the host galaxies proper. These connections are particularly striking in the interacting and barred galaxies. Such structures are predicted by numerical simulations of gas flows in barred and interacting galaxies, and may be related to the fueling of AGN by matter inflow from the host galaxy disks. We see no significant differences in the circumnuclear dust morphologies of Seyfert 1s and 2s, and very few Seyfert 2 nuclei are obscured by large-scale dust structures in the host galaxies. If Seyfert 2s are obscured Seyfert 1s, then the obscuration must occur on smaller scales than those probed by HST.
Richard W. Pogge; Paul Martini
Material Disposal Areas
Material Disposal Areas Material Disposal Areas Material Disposal Areas Material Disposal Areas, also known as MDAs, are sites where material was disposed of below the ground surface in excavated pits, trenches, or shafts. Contact Environmental Communication & Public Involvement P.O. Box 1663 MS M996 Los Alamos, NM 87545 (505) 667-0216 Email Material Disposal Areas at LANL The following are descriptions and status updates of each MDA at LANL. To view a current fact sheet on the MDAs, click on LA-UR-13-25837 (pdf). MDA A MDA A is a Hazard Category 2 nuclear facility comprised of a 1.25-acre, fenced, and radiologically controlled area situated on the eastern end of Delta Prime Mesa. Delta Prime Mesa is bounded by Delta Prime Canyon to the north and Los Alamos Canyon to the south.
Neutrino telescopes as a probe of active and sterile neutrino mixings
If the ultrahigh-energy (UHE) neutrino fluxes produced from a distant astrophysical source can be measured at a km^3-size neutrino telescope, they will provide a promising way to help determine the flavor mixing pattern of three active neutrinos. Considering the conventional UHE neutrino source with the flavor ratio \\phi_e : \\phi_\\mu : \\phi_\\tau = 1 : 2 : 0, I show that \\phi^D_e : \\phi^D_\\mu : \\phi^D_\\tau = (1 -2 \\Delta) : (1 +\\Delta) : (1 +\\Delta) holds at the detector of a neutrino telescope, where \\Delta characterizes the effect of \\mu-\\tau symmetry breaking (i.e., \\theta_13 \
Xing, Zhi-zhong
Zhi-zhong Xing
The Liverpool Telescope Automatic Pipeline for Real-time GRB Afterglow Detection
The 2-m robotic Liverpool Telescope (LT) is ideally suited to the rapid follow-up of unpredictable and transient events such as GRBs. Our GRB follow-up strategy is designed to identify optical/IR counterparts in real time; it involves the automatic triggering of initial observations, on receipt of an alert from Gamma Ray Observatories HETE-2, INTEGRAL and Swift, followed by automated data reduction, analysis, OT identification and subsequent observing mode choice. The lack of human intervention in this process requires robustness at all stages of the procedure. Here we describe the telescope, its instrumentation and GRB pipeline.
A. Gomboc; A. Monfardini; C. Guidorzi; C. G. Mundell; C. J. Mottram; S. N. Fraser; R. J. Smith; I. A. Steele; D. Carter; M. F. Bode; A. M. Newsam
Implicit Large Eddy Simulation
National Nuclear Security Administration (NNSA)
Implicit Implicit Large Eddy Simulation (ILES) for High Reynolds Number Flows Len Margolin Applied Physics Division Los Alamos National Laboratory Collaborators: 1. Bill Rider (LANL) 2. Piotr Smolarkiewicz (NCAR) 3. Andrzej Wysogrodski (NCAR) 4. Fernando Grinstein (NRL) firstname.lastname@example.com 1 Implicit Large Eddy Simulation Outline: * What is ILES? * What are its advantages? * Historical perspective * Why does it work? * Some examples firstname.lastname@example.com 2 What is ILES ILES is the direct application of a fluid solver to a high Reynolds number fluid flow with no explicit turbulence model. · The truncation terms of the algorithm serve as an effective model of the effects of the unresolved scales. · Fluid solvers based on Nonoscillatory Finite Volume (NFV) approximations work effectively for ILES. · Fluid solvers based on pseudospectral methods, leapfrog methods, advective form methods, etc. do not work
NIST Aperture area measurements
... particularly critical, for example, in climate and weather applications on ... of aperture areas used in exo-atmospheric solar irradiance measurements; ...
Naval applications study areas
This memorandum discusses study areas and items that will require attention for the naval studies of the utilization of nuclear propulsion in a submarine-based missile system.
Hadley, J. W.
Boulder Area Transportation
... NIST does not endorse or guarantee the quality or services provided by these businesses. All Denver/Boulder area transportation companies. ...
We have used the Spitzer Space Telescope Infrared Spectrograph (IRS) to observe the 5-37 {mu}m thermal emission of comet 73P/Schwassmann-Wachmann 3 (SW3), components B and C. We obtained low spectral resolution (R {approx} 100) data over the entire wavelength interval, along with images at 16 and 22 {mu}m. These observations provided an unprecedented opportunity to study nearly pristine material from the surface and what was until recently the interior of an ecliptic comet-the cometary surface having experienced only two prior perihelion passages, and including material that was totally fresh. The spectra were modeled using a variety of mineral types including both amorphous and crystalline components. We find that the degree of silicate crystallinity, {approx}35%, is somewhat lower than most other comets with strong emission features, while its abundance of amorphous carbon is higher. Both suggest that SW3 is among the most chemically primitive solar system objects yet studied in detail, and that it formed earlier or farther from the Sun than the bulk of the comets studied so far. The similar dust compositions of the two fragments suggest that these are not mineralogically heterogeneous, but rather uniform throughout their volumes. The best-fit particle size distribution for SW3B has a form dn/da {approx} a{sup -3.5}, close to that expected for dust in collisional equilibrium, while that for SW3C has dn/da {approx} a{sup -4.0}, as seen mostly in active comets with strong directed jets, such as C/1995 O1 Hale-Bopp. The total mass of dust in the comae plus nearby tail, extrapolated from the field of view of the IRS peak-up image arrays, is (3-5) x 10{sup 8} kg for B and (7-9) x 10{sup 8} kg for C. Atomic abundances derived from the spectral models indicate a depletion of O compared to solar photospheric values, despite the inclusion of water ice and gas in the models. Atomic C may be solar or slightly sub-solar, but its abundance is complicated by the potential contribution of spectrally featureless mineral species to the portion of the spectra most sensitive to the derivation of the C abundance. We find a relatively high bolometric albedo, {approx}0.13 for the dust, considering the large amount of dark carbonaceous material, but consistent with the presence of abundant small particles and strong emission features.
Sitko, Michael L.; Whitney, Barbara A.; Wolff, Michael J. [Space Science Institute, Boulder, CO 80301 (United States); Lisse, Carey M. [Applied Physics Lab, Johns Hopkins University, Laurel, MD 20723 (United States); Kelley, Michael S. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Polomski, Elisha F. [Department of Physics and Astronomy, University of Wisconsin, Eau Claire, WI 54702 (United States); Lynch, David K.; Russell, Ray W. [Aerospace Corporation, Los Angeles, CA 90009 (United States); Kimes, Robin L. [Department of Physics, University of Cincinnati, Cincinnati, OH 45221 (United States); Harker, David E., E-mail: email@example.com, E-mail: email@example.com, E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com, E-mail: email@example.com, E-mail: email@example.com, E-mail: firstname.lastname@example.com, E-mail: email@example.com, E-mail: email@example.com, E-mail: email@example.com [Center for Astrophysics and Space Science, University of California at San Diego, La Jolla, CA 92093 (United States)
Search for ultra-high energy photons using Telescope Array surface detector
We search for ultra-high energy photons by analyzing geometrical properties of shower fronts of events registered by the Telescope Array surface detector. By making use of an event-by-event statistical method, we derive an upper limit on the absolute flux of primary photons with energies above 10{sup 19} eV.
Rubtsov, G. I.; Troitsky, S. V. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow, 117312 (Russian Federation); Ivanov, D.; Stokes, B. T. [Rutgers - State University of New Jersey, Piscataway (United States); Thomson, G. B. [University of Utah, High Energy Astrophysics Institute, Salt Lake City, Utah (United States)
Search for Short Duration Bursts of TeV Gamma Rays with the Milagrito Telescope
OG 2.3.07 Search for Short Duration Bursts of TeV Gamma Rays with the Milagrito Telescope Gus for short duration bursts of TeV photons. Such bursts may result from "traditional" gamma-ray bursts to gamma-ray bursts, the final stages of black hole evaporation) the most compelling reason may
California at Santa Cruz, University of
Solar Physics, Space Weather, and Wide-field X-ray Telescopes
Solar Physics, Space Weather, and Wide-field X-ray Telescopes CREOL & FPCE: The College of Optics of the Earth). The detrimental effects of solar storm induced "space weather" ranges from disruption of our. The National Oceanic & Atmospheric Administration (NOAA) and NASA are cooperating on a Solar X-ray Imager (SXI
Van Stryland, Eric
Focal plane instrumentation for the Wide-Field X-ray Telescope
The three X-ray imaging focal planes of the Wide-Field X-ray Telescope (WFXT) Mission will each have a field of view up to 1 degree square, pixel pitch smaller than 1 arcsec, excellent X-ray detection efficiency and spectral ...
Bautz, Marshall W.
Fueling area site assessment
This report provides results of a Site Assessment performed at the Fuel Storage Area at Buckley ANG Base in Aurora, Colorado. Buckley ANG Base occupies 3,328 acres of land within the City of Aurora in Arapahoe County, Colorado. The Fuel Storage Area (also known as the Fueling Area) is located on the west side of the Base at the intersection of South Powderhorn Street and East Breckenridge Avenue. The Fueling Area consists of above ground storage tanks in a bermed area, pumps, piping, valves, an unloading stand and a fill stand. Jet fuel from the Fueling Area is used to support aircraft operations at the Base. Jet fuel is stored in two 200,000 gallon above ground storage tanks. Fuel is received in tanker trucks at the unloading stand located south and east of the storage tanks. Fuel required for aircraft fueling and other use is transferred into tanker trucks at the fill stand and transported to various points on the Base. The Fuel Storage Area has been in operation for over 20 years and handles approximately 7 million gallons of jet fuel annually.
area | OpenEI
area area Dataset Summary Description These estimates are derived from a composite of high resolution wind resource datasets modeled for specific countries with low resolution data originating from the National Centers for Environmental Prediction (United States) and the National Center for Atmospheric Research (United States) as processed for use in the IMAGE model. The high resolution datasets were produced by the National Renewable Energy Laboratory (United States), Risø DTU National Laboratory (Denmark), the National Institute for Space Research (Brazil), and the Canadian Wind Energy Association. The data repr Source National Renewable Energy Laboratory Date Released Unknown Date Updated Unknown Keywords area capacity clean energy international National Renewable Energy Laboratory
NSTB Summarizes Vulnerable Areas
NSTB Summarizes Vulnerable Areas NSTB Summarizes Vulnerable Areas Commonly Found in Energy Control Systems Experts at the National SCADA Test Bed (NSTB) discovered some common areas of vulnerability in the energy control systems assessed between late 2004 and early 2006. These vulnerabilities ranged from conventional IT security issues to specific weaknesses in control system protocols. The paper "Lessons Learned from Cyber Security Assessments of SCADA and Energy Management Systems" describes the vulnerabilities and recommended strategies for mitigating them. It should be of use to asset owners and operators, control system vendors, system integrators, and third-party vendors interested in enhancing the security characteristics of current and future products.
Geographic Area Month
Gasoline and Diesel Fuel Update (EIA)
Fuels by PAD District and State (Cents per Gallon Excluding Taxes) - Continued Geographic Area Month No. 1 Distillate No. 2 Distillate a No. 4 Fuel b Sales to End Users Sales for...
3. Producing Areas
U.S. Energy Information Administration (EIA)
The OCS area provides surplus capacity to meet major seasonal swings in the lower 48 States gas requirements. The ... Jun-86 9,878 17,706 1,460 19,166 9,288 51.5
{sm_bullet} Uranium fuel production {sm_bullet} Test reactor and separations experiments {sm_bullet} Animal and radiobiology experiments conducted at the. 331 Laboratory Complex {sm_bullet} .Deactivation, decontamination, decommissioning,. and demolition of 300 Area facilities
Decontamination & decommissioning focus area
In January 1994, the US Department of Energy Office of Environmental Management (DOE EM) formally introduced its new approach to managing DOE`s environmental research and technology development activities. The goal of the new approach is to conduct research and development in critical areas of interest to DOE, utilizing the best talent in the Department and in the national science community. To facilitate this solutions-oriented approach, the Office of Science and Technology (EM-50, formerly the Office of Technology Development) formed five Focus AReas to stimulate the required basic research, development, and demonstration efforts to seek new, innovative cleanup methods. In February 1995, EM-50 selected the DOE Morgantown Energy Technology Center (METC) to lead implementation of one of these Focus Areas: the Decontamination and Decommissioning (D & D) Focus Area.
Western Area Power Administration
Loveland Area Projects November 29-30, 2011 2 Agenda * Overview of Western Area Power Administration * Post-1989 Loveland Area Projects (LAP) Marketing Plan * Energy Planning and Management Program * Development of the 2025 PMI Proposal * 2025 PMI Proposal * 2025 PMI Comment Period & Proposal Information * Questions 3 Overview of Western Area Power Administration (Western) * One of four power marketing administrations within the Department of Energy * Mission: Market and deliver reliable, renewable, cost-based Federal hydroelectric power and related services within a 15-state region of the central and western U.S. * Vision: Provide premier power marketing and transmission services Rocky Mountain Region (RMR) is one of five regional offices 4 Rocky Mountain Region
APS Area Emergency Supervisors
Area Emergency Supervisors BUILDING AES AAES 400-EAA Raul Mascote Debra Eriksen-Bubulka 400-A (SPX) Tim Jonasson 400-Sectors 25-30 Reggie Gilmore 401-CLO Steve Downey Ed Russell...
Advanced concepts in large-scale network simulation
This tutorial paper reviews existing concepts and future directions in selected areas related to simulation of large-scale networks. It covers specifically topics in traffic modeling, simulation of routing, network emulation, and real-time simulation.
David M. Nicol; Michael Liljenstam; Jason Liu
Flight Performance of an advanced CZT Imaging Detector in a Balloon-borne Wide-Field Hard X-ray Telescope - ProtoEXIST1
We successfully carried out the first high-altitude balloon flight of a wide-field hard X-ray coded-aperture telescope ProtoEXIST1, which was launched from the Columbia Scientific Balloon Facility at Ft. Sumner, New Mexico on October 9, 2009. ProtoEXIST1 is the first implementation of an advanced CdZnTe (CZT) imaging detector in our ongoing program to establish the technology required for next generation wide-field hard X-ray telescopes. The CZT detector plane in ProtoEXIST1 consists of an 8 x 8 array of closely tiled 2 cm x 2 cm x 0.5 cm thick pixellated CZT crystals, each with 8 x 8 pixels, covering a 256 cm^2 active area with 2.5 mm pixels. A tungsten mask, mounted at 90 cm above the detector provides shadowgrams of X-ray sources in the 30 - 600 keV band for imaging, allowing a fully coded field of view of 9 Deg x 9 Deg with an angular resolution of 20 arcmin. To reduce the background radiation, the detector is surrounded by semi-graded (Pb/Sn/Cu) passive shields on the four sides all the way to the mask. ...
Hong, J; Grindlay, J; Barthelemy, S; Baker, R; Garson, A; Krawczynski, H; Apple, J; Cleveland, W H
A Detailed Study of FDIRC Prototype with Waveform Digitizing Electronics in Cosmic Ray Telescope Using 3D Tracks
We present a detailed study of a novel Cherenkov imaging detector called the Focusing DIRC (FDIRC) with waveform digitizing electronics. In this test study, the FDIRC prototype has been instrumented with seven Hamamatsu H-8500 MaPMTs. Waveforms from {approx}450 pixels are digitized with waveform sampling electronics based on the BLAB2 ASIC, operating at a sampling speed of {approx}2.5 GSa/s. The FDIRC prototype was tested in a large cosmic ray telescope (CRT) providing 3D muon tracks with {approx}1.5 mrad angular resolution and muon energy of E{sub muon} > 1.6 GeV. In this study we provide a detailed analysis of the tails in the Cherenkov angle distribution as a function of various variables, compare experimental results with simulation, and identify the major contributions to the tails. We demonstrate that to see the full impact of these tails on the Cherenkov angle resolution, it is crucial to use 3D tracks, and have a full understanding of the role of ambiguities. These issues could not be fully explored in previous FDIRC studies where the beam was perpendicular to the quartz radiator bars. This work is relevant for the final FDIRC prototype of the PID detector at SuperB, which will be tested this year in the CRT setup.
Nishimura, K.; Dey, B.; /Hawaii U. /UC, Riverside; Aston, D.; Leith, D.W.G.S.; Ratcliff, B.; /SLAC; Roberts, D.; /Maryland U.; Ruckman, L.; /Hawaii U.; Shtol, D.; /Novosibirsk, IYF; Varner, G.S.; /Hawaii U.; Va'vra, J.; Vavra, Jerry; /SLAC
Operational Area Monitoring Plan
Office of Legacy Management (LM)
' ' SECTION 11.7B Operational Area Monitoring Plan for the Long -Term H yd rol og ical M o n i to ri ng - Program Off The Nevada Test Site S . C. Black Reynolds Electrical & Engineering, Co. and W. G. Phillips, G. G. Martin, D. J. Chaloud, C. A. Fontana, and 0. G. Easterly Environmental Monitoring Systems Laboratory U. S. Environmental Protection Agency October 23, 1991 FOREWORD This is one of a series of Operational Area Monitoring Plans that comprise the overall Environmental Monitoring Plan for the DOE Field Office, Nevada (DOEINV) nuclear and non- nuclear testing activities associated with the Nevada Test Site (NTS). These Operational Area Monitoring Plans are prepared by various DOE support contractors, NTS user organizations, and federal or state agencies supporting DOE NTS operations. These plans and the parent
Lessons from Large-Scale Renewable Energy Integration Studies: Preprint
In general, large-scale integration studies in Europe and the United States find that high penetrations of renewable generation are technically feasible with operational changes and increased access to transmission. This paper describes other key findings such as the need for fast markets, large balancing areas, system flexibility, and the use of advanced forecasting.
Bird, L.; Milligan, M.
Conflict between the identification of a cosmic neutrino source and the sensitivity to mixing angles in a neutrino telescope
Neutrino fluxes at telescopes depend on both initial fluxes out of astronomical bursts and flavor mixing during their travel to the Earth. However, since the information on the initial composition requires better precision in mixing angles and vice versa, neutrino detection at telescopes cannot provide solutions to both problems by itself. Thus, a probability to be measured at long-baseline oscillation is considered as a complement to the telescope, and problems like source identification and parameter degeneracy are examined under a few assumptions.
Hwang, Ggyoung-Riun; Siyeon, Kim [Department of Physics, Chung-Ang University, Seoul 156-756 (Korea, Republic of)
Within the hierarchical framework for galaxy formation, minor merging and tidal interactions are expected to shape all large galaxies to the present day. As a consequence, most seemingly normal disk galaxies should be surrounded by spatially extended stellar 'tidal features' of low surface brightness. As part of a pilot survey for such interaction signatures, we have carried out ultra deep, wide field imaging of eight isolated spiral galaxies in the Local Volume, with data taken at small (D = 0.1-0.5 m) robotic telescopes that provide exquisite surface brightness sensitivity ({mu}{sub lim}(V) {approx} 28.5 mag arcsec{sup -2}). This initial observational effort has led to the discovery of six previously undetected extensive (to {approx}30 kpc) stellar structures in the halos surrounding these galaxies, likely debris from tidally disrupted satellites. In addition, we confirm and clarify several enormous stellar over-densities previously reported in the literature, but never before interpreted as tidal streams. Even this pilot sample of galaxies exhibits strikingly diverse morphological characteristics of these extended stellar features: great circle-like features that resemble the Sagittarius stream surrounding the Milky Way, remote shells and giant clouds of presumed tidal debris far beyond the main stellar body, as well as jet-like features emerging from galactic disks. Together with presumed remains of already disrupted companions, our observations also capture surviving satellites caught in the act of tidal disruption. A qualitative comparison with available simulations set in a {Lambda}Cold Dark Matter cosmology (that model the stellar halo as the result of satellite disruption evolution) shows that the extraordinary variety of stellar morphologies detected in this pilot survey matches that seen in those simulations. The common existence of these tidal features around 'normal' disk galaxies and the morphological match to the simulations constitutes new evidence that these theoretical models also apply to a large number of other Milky Way-mass disk galaxies in the Local Volume.
MartInez-Delgado, David; Zibetti, Stefano; Rix, Hans-Walter [Max Planck Institut fuer Astronomie, Heidelberg (Germany); Gabany, R. Jay [Black Bird Observatory, Mayhill, NM (United States); Crawford, Ken [Rancho del Sol Observatory, Modesto, CA (United States); Majewski, Steven R.; McDavid, David A. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Fliri, Juergen; Carballo-Bello, Julio A.; Bardalez-Gagliuffi, Daniella C.; Trujillo, Ignacio [Instituto de Astrofisica de Canarias, La Laguna (Spain); Penarrubia, Jorge [Institute of Astronomy, University of Cambridge (United Kingdom); Chonis, Taylor S. [Department of Astronomy, University of Texas, Austin, TX 78712-0259 (United States); Madore, Barry [The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Schirmer, Mischa [Argelander Institut fuer Astronomie, Universitaet Bonn (Germany)
Influence of aerosols from biomass burning on the spectral analysis of Cherenkov telescopes
During the last decade, imaging atmospheric Cherenkov telescopes (IACTs) have proven themselves as astronomical detectors in the very-high-energy (VHE; E>0.1 TeV) regime. The IACT technique observes the VHE photons indirectly, using the Earth's atmosphere as a calorimeter. Much of the calibration of Cherenkov telescope experiments is done using Monte Carlo simulations of the air shower development, Cherenkov radiation and detector, assuming certain models for the atmospheric conditions. Any deviation of the real conditions during observations from the assumed atmospheric model will result in a wrong reconstruction of the primary gamma-ray energy and the resulting source spectra. During eight years of observations, the High Energy Stereoscopic System (H.E.S.S.) has experienced periodic natural as well as anthropogenic variations of the atmospheric transparency due to aerosols created by biomass burning. In order to identify data that have been taken under such long-term reductions in atmospheric transparency, ...
Reyes, R de los; Bernloehr, K; Krueger, P; Deil, C; Gast, H; Kosack, K; Marandon, V
A multipurpose TIM-based optical telescope for Omega and the Trident laser facilities
The authors have recently designed and are building a telescope which acts as an imaging light collector relaying the image to an optical table for experiment dependent analysis and recording. The expected primary use of this instrument is a streaked optical pyrometer for witness plate measurements of Hohlraum drive temperature. The telescope is based on University of Rochester`s Ten-Inch Manipulator (TIM) which allows compatibility between Omega, Trident, and the NIF lasers. The optics capture a f/7 cone of light, have a field of view of 6-mm, have a spatial resolution of 5 to 7-{micro}m per line pair at the object plane, and are optimized for operation at 280-nm. The image is at a magnification of 11.7x, which is convenient for many experiments, but can be changed using additional optics that reside outside the TIM.
Oertel, J.A.; Murphy, T.J.; Berggren, R.R. [and others
Development and Performance of the PHOT (Portable High-Speed Occultation Telescope) Systems
The PHOT (Portable High-Speed Occultation Telescope) systems were developed for the specific purpose of observing stellar occultations by solar system objects. Stellar occultations have unique observing constraints: they may only be observable from certain parts of the globe; they often require a rapid observing cadence; and they require accurate timestamp information for each exposure. The PHOT systems consist of 14" telescopes, CCD cameras, camera mounting plates, GPS-based time standards, and data acquisition computers. The PHOT systems are similar in principle to the POETS systems (Portable Occultation, Eclipse and Transit Systems, described by Souza et al. 2006 and reported on by Gulbis et al. 2008), with the main differences being (a) different CCD/Cameras with slightly different specifications and (b) a stand-alone custom-built time standard used by PHOT, whereas POETS uses a commercial time-standard that is controlled from a computer. Since 2005, PHOT systems have been deployed on over two dozen occas...
Young, E F; Olkin, C B; Shoemaker, K; French, R G; Regester, J; Buie, M W
The MAGIC telescopes DAQ software and the on-the-fly online analysis client
In this contribution we describe the design of the Data AcQuisition (DAQ) and online analysis software of the MAGIC telescopes after the 2012 upgrade. Although the final stereo trigger requires coincidence between the two telescopes, the actual data acquisition is performed independently, producing two separate data streams. Events are first readout and built from the front-end electronics and then stored in the DAQs' internal ring buffer for further processing: pre-calibration and signal extraction. The pixel signals, previously used only for data quality monitoring, are now also sent "on-the-fly" to the centralized online analysis program MOLA, which acts as a single client for the two DAQ data streams, and uses this information to provide preliminary high level analysis results. The integrated DAQ and online analysis programs allows an immediate feedback in case of a rapid gamma-ray flare of the pointed astrophysical source.
Diego Tescaro; Alicia López-Oramas; Abelardo Moralejo; Daniel Mazin; Daniela Hadasch for the MAGIC Collaboration
Remote control and telescope auto-alignment system for multiangle LIDAR under development at CEILAP, Argentina
At CEILAP (CITEDEF-CONICET), a multiangle LIDAR is under development to monitor aerosol extinction coefficients in the frame of the CTA (Cherenkov Telescope Array) Project. This is an initiative to build the next generation of ground-based instruments to collect very high energy gamma-ray radiation (>10 GeV). The atmospheric conditions are very important for CTA observations, and LIDARs play an important role in the measurement of the aerosol optical depth at any direction. The LIDAR being developed at CEILAP was conceived to operate in harsh environmental conditions during the shifts, and these working conditions may produce misalignments. To minimize these effects, the telescopes comprising the reception unit are controlled by a self-alignment system. This paper describes the self-alignment method and hardware automation.
Pallotta, Juan; Otero, Lidia; Chouza, Fernando; Raul, Delia; Gonzalez, Francisco; Etchegoyen, Alberto; Quel, Eduardo
Bay Area | Open Energy Information
Bay Area Bay Area Jump to: navigation, search Contents 1 Clean Energy Clusters in the Bay Area 1.1 Products and Services in the Bay Area 1.2 Research and Development Institutions in the Bay Area 1.3 Networking Organizations in the Bay Area 1.4 Investors and Financial Organizations in the Bay Area 1.5 Policy Organizations in the Bay Area Clean Energy Clusters in the Bay Area Products and Services in the Bay Area Loading map... {"format":"googlemaps3","type":"ROADMAP","types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"limit":500,"offset":0,"link":"all","sort":[""],"order":[],"headers":"show","mainlabel":"","intro":"","outro":"","searchlabel":"\u2026
Texas Area | Open Energy Information
Area Area Jump to: navigation, search Contents 1 Clean Energy Clusters in the Texas Area 1.1 Products and Services in the Texas Area 1.2 Research and Development Institutions in the Texas Area 1.3 Networking Organizations in the Texas Area 1.4 Investors and Financial Organizations in the Texas Area 1.5 Policy Organizations in the Texas Area Clean Energy Clusters in the Texas Area Products and Services in the Texas Area Loading map... {"format":"googlemaps3","type":"ROADMAP","types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"limit":500,"offset":0,"link":"all","sort":[""],"order":[],"headers":"show","mainlabel":"","intro":"","outro":"","searchlabel":"\u2026
Rockies Area | Open Energy Information
Rockies Area Rockies Area Jump to: navigation, search Contents 1 Clean Energy Clusters in the Rockies Area 1.1 Products and Services in the Rockies Area 1.2 Research and Development Institutions in the Rockies Area 1.3 Networking Organizations in the Rockies Area 1.4 Investors and Financial Organizations in the Rockies Area 1.5 Policy Organizations in the Rockies Area Clean Energy Clusters in the Rockies Area Products and Services in the Rockies Area Loading map... {"format":"googlemaps3","type":"ROADMAP","types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"limit":500,"offset":0,"link":"all","sort":[""],"order":[],"headers":"show","mainlabel":"","intro":"","outro":"","searchlabel":"\u2026
Elements heavier than the iron group are found in nearly all halo stars. A substantial number of these elements, key to understanding neutron-capture nucleosynthesis mechanisms, can only be detected in the near-ultraviolet. We report the results of an observing campaign using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope to study the detailed heavy-element abundance patterns in four metal-poor stars. We derive abundances or upper limits from 27 absorption lines of 15 elements produced by neutron-capture reactions, including seven elements (germanium, cadmium, tellurium, lutetium, osmium, platinum, and gold) that can only be detected in the near-ultraviolet. We also examine 202 heavy-element absorption lines in ground-based optical spectra obtained with the Magellan Inamori Kyocera Echelle Spectrograph on the Magellan-Clay Telescope at Las Campanas Observatory and the High Resolution Echelle Spectrometer on the Keck I Telescope on Mauna Kea. We have detected up to 34 elements heavier than zinc. The bulk of the heavy elements in these four stars are produced by r-process nucleosynthesis. These observations affirm earlier results suggesting that the tellurium found in metal-poor halo stars with moderate amounts of r-process material scales with the rare earth and third r-process peak elements. Cadmium often follows the abundances of the neighboring elements palladium and silver. We identify several sources of systematic uncertainty that must be considered when comparing these abundances with theoretical predictions. We also present new isotope shift and hyperfine structure component patterns for Lu II and Pb I lines of astrophysical interest.
Roederer, Ian U.; Thompson, Ian B. [Carnegie Observatories, Pasadena, CA 91101 (United States); Lawler, James E. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Sobeck, Jennifer S. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Beers, Timothy C. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Cowan, John J. [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States); Frebel, Anna [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, Cambridge, MA 02139 (United States); Ivans, Inese I. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Schatz, Hendrik [Department of Physics and Astronomy, Michigan State University, E. Lansing, MI 48824 (United States); Sneden, Christopher [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States)
High Precision CTE-Measurement of SiC-100 for Cryogenic Space-Telescopes
We present the results of high precision measurements of the thermal expansion of the 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 $\\sim$ 10 K. Three samples, #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 the 8th order polynomial of the temperature. For the three samples, the coefficients of thermal expansion (CTE), $\\bar{\\alpha}_{#1}$, $\\bar{\\alpha}_{#2}$, and $\\bar{\\alpha}_{#3}$ were derived for temperatures between 293 K and 10 K. The average and the dispersion (1 $\\sigma$ rms) of these three CTEs are 0.816 and 0.002 ($\\times 10^{-6}$/K), 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 obtained CTE dispersion, we performed an 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 a sufficient accuracy well enough for the design of the 3.5 m cryogenic infrared telescope mission, the Space Infrared telescope for Cosmology and Astrophysics (SPICA).
K. Enya; N. Yamada; T. Onaka; T. Nakagawa; H. Kaneda; M. Hirabayashi; Y. Toulemont; D. Castel; Y. Kanai; N. Fujishiro
Search for neutrinos from Gamma-Ray Bursts with the Baikal neutrino telescope NT200
We present an analysis of neutrinos detected with the Baikal neutrino telescope NT200 for correlations with gamma-ray bursts (GRB). No neutrino events correlated with GRB were observed. Assuming a Waxman-Bahcall spectrum, a neutrino flux upper limit of {\\bf $E^2 \\Phi Green's Function fluence limit for this search, which extends two orders of magnitude beyond the energy range of the Super-Kamiokande limit.
Avrorin, A
Hubble Space Telescope Imaging of the Young Planetary Nebula GL 618
We present narrow-band Hubble Space Telescope images of the young planetary nebula GL 618. These images have allowed us to study the detailed morphology of shock-excited emission present in the bipolar lobes of this object. These images reveal the presence of three highly collimated outflows emanating from the central regions of GL 618. We discuss the significance of the detection of these outflows and the possible origins of these features.
Susan R. Trammell
The european FAZIA initiative: a high-performance digital telescope array for heavy-ion studies
The european Fazia collaboration aims at building a new modular array for charged product identification to be employed for heavy-ion studies. The elementary module of the array is a Silicon-Silicon-CsI telescope, optimized for ion identification also via pulse shape analysis. The achievement of top performances imposes specific electronics which has been developed by FAZIA and features high quality charge and current preamplifiers, coupled to fully digital front-end. During the initial R&D phase, original and novel solutions have been tested in prototypes, obtaining unprecedented ion identification capabilities. FAZIA is now constructing a demonstrator array consisting of about two hundreds telescopes arranged in a compact and transportable configuration. In this contribution, we mainly summarize some aspects studied by FAZIA to improve the ion identification. Then we will briefly discuss the FAZIA program centered on experiments to be done with the demonstrator. First results on the isospin dynamics obtained with a reduced set-up demonstrate well the performance of the telescope and represent a good starting point towards future investigations with both stable and exotic beams.
G. Casini; S. Barlini; G. Pasquali; G. Pastore; M. Bini; S. Carboni; A. Olmi; S. Piantelli; G. Poggi; A. Stefanini; S. Valdre'; E. Bonnet; B. Borderie; R. Bougault; M. Bruno; A. Chbihi; M. Cinausero; M. Degerlier; P. Edelbruck; J. D. Frankland; F. Gramegna; D. Gruyer; M. Guerzoni; A. Kordjasz; T. Kozik; N. Le Neindre; O. Lopez; T. Marchi; P. Marini; L. Morelli; A. Ordine; M. Parlog; M. F. Rivet; E. Rosato; F. Salomon; G. Spadaccini; T. Twarog; E. Vient; M. Vigilante
The Automatic Real-Time GRB Pipeline of the 2-m Liverpool Telescope
The 2-m Liverpool Telescope (LT), owned by Liverpool John Moores University, is located in La Palma (Canary Islands) and operates in fully robotic mode. In 2005, the LT began conducting an automatic GRB follow-up program. On receiving an automatic GRB alert from a Gamma-Ray Observatory (Swift, INTEGRAL, HETE-II, IPN) the LT initiates a special override mode that conducts follow-up observations within 2-3 min of the GRB onset. This follow-up procedure begins with an initial sequence of short (10-s) exposures acquired through an r' band filter. These images are reduced, analyzed and interpreted automatically using pipeline software developed by our team called "LT-TRAP" (Liverpool Telescope Transient Rapid Analysis Pipeline); the automatic detection and successful identification of an unknown and potentially fading optical transient triggers a subsequent multi-color imaging sequence. In the case of a candidate brighter than r'=15, either a polarimetric (from 2006) or a spectroscopic observation (from 2007) will be triggered on the LT. If no candidate is identified, the telescope continues to obtain z', r' and i' band imaging with increasingly longer exposure times. Here we present a detailed description of the LT-TRAP and briefly discuss the illustrative case of the afterglow of GRB 050502a, whose automatic identification by the LT just 3 min after the GRB, led to the acquisition of the first early-time (< 1 hr) multi-color light curve of a GRB afterglow.
C. Guidorzi; A. Monfardini; A. Gomboc; C. J. Mottram; C. G. Mundell; I. A. Steele; D. Carter; M. F. Bode; R. J. Smith; S. N. Fraser; M. J. Burgdorf; A. M. Newsam
Microscopic surface structure of C/SiC composite mirrors for space cryogenic telescopes
We report on the microscopic surface structure of carbon-fiber-reinforced silicon carbide (C/SiC) composite mirrors that have been improved for the Space Infrared Telescope for Cosmology and Astrophysics (SPICA) and other cooled telescopes. The C/SiC composite consists of carbon fiber, silicon carbide, and residual silicon. Specific microscopic structures are found on the surface of the bare C/SiC mirrors after polishing. These structures are considered to be caused by the different hardness of those materials. The roughness obtained for the bare mirrors is 20 nm rms for flat surfaces and 100 nm rms for curved surfaces. It was confirmed that a SiSiC slurry coating is effective in reducing the roughness to 2 nm rms. The scattering properties of the mirrors were measured at room temperature and also at 95 K. No significant change was found in the scattering properties through cooling, which suggests that the microscopic surface structure is stable with changes in temperature down to cryogenic values. The C/SiC mirror with the SiSiC slurry coating is a promising candidate for the SPICA telescope.
Keigo Enya; Takao Nakagawa; Hidehiro Kaneda; Takashi Onaka; Tuyoshi Ozaki; Masami Kume
Aspects of mechanical design for an infrared robotic telescope in Antarctica: IRAIT
The purpose of this thesis is to focus attention on the mechanical aspects in designing an infrared telescope, IRAIT (International Robotic Antarctic Infrared Telescope), with aperture size of 80 cm, f#=21, entirely robotic and remote controlled, which must operate at Dome C, on Antarctic Plateau, starting on Summer 2007. Before illustrating in detail the choice criteria of different mechanical components, in order to satisfy stress requirements and structural verification, and the final design solutions we have adopted,firstly a few tissues must be considered. They mainly concern the preference for Dome C as probably the best observing site in the world, the scientific targets, instruments and tools necessary to reach such goals. The mechanical structure of telescope has been analyzed, and results retrieved by the static and dynamic analysis through a finite element software are illustrated. They concern the behavior of single parts, subassemblies and overall structure to active loads applied. It is shown that, as a matter of fact, thermal stress can be reckoned as the most influent of all static loads. A dynamic analysis of some critical subassemblies was used,in order to determine the frequency response of the system aiming at its best insulation from vibrations.
Igor Di VArano
A decision-making framework to determine the value of on-orbit servicing compared to replacement of space telescopes
The Hubble Space Telescope has demonstrated that on-orbit servicing can provide significant benefits for scientific space programs. Specifically, servicing missions can replace failed components to keep spacecraft operational, ...
Baldesarra, Mark
CRaTER: The Cosmic Ray Telescope for the Effects of Radiation Experiment on the Lunar Reconnaissance Orbiter Mission
The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) on the Lunar Reconnaissance Orbiter (LRO) characterizes the radiation environment to be experienced by humans during future lunar missions. CRaTER measures the ...
Spence, H. E.
CALIFORNIA ENERGY Large HVAC Building
CALIFORNIA ENERGY COMMISSION Large HVAC Building Survey Information Database of Buildings over 100 Design of Large Commercial HVAC Systems research project, one of six research elements in the Integrated Design of Large Commercial HVAC Systems Integrated Design of Small Commercial HVAC Systems Integrated
Focus Area Summary
information provided was consolidated from the original five focus areas for the EM information provided was consolidated from the original five focus areas for the EM Corporate QA Board. The status of QAP/QIP approvals etc. was accurate at the time of posting; however, additional approvals may have been achieved since that time. If you have any questions about the information provided, please contact Bob Murray at firstname.lastname@example.com Task # Task Description Status 1.1 Develop a brief questionnaire to send out to both commercial and EM contractors to describe their current approach for identifying the applicable QA requirements for subcontractors, tailoring the requirements based upon risk, process for working with procurement to ensure QA requirements are incorporated into subcontracts, and implementing verification of requirement flow-down by their
Focus Area 3 Deliverables
3 - Commercial Grade item and Services 3 - Commercial Grade item and Services Dedication Implementation and Nuclear Services Office of Environmental Management And Energy Facility Contractors Group Quality Assurance Improvement Project Plan Project Focus Area Task # and Description Deliverable Project Area 3-Commercial Grade Item and Services Dedication 3.1-Complete a survey of selected EM contractors to identify the process and basis for their CGI dedication program including safety classification of items being dedicated for nuclear applications within their facilities Completed Survey Approvals: Yes/No/NA Project Managers: S. Waisley, D. Tuttel Yes Executive Committee: D. Chung, J. Yanek, N. Barker, D. Amerine No EM QA Corporate Board: No Energy Facility Contractors Group
Argonne area restaurants
area restaurants area restaurants Amber Cafe 13 N. Cass Ave. Westmont, IL 60559 630-515-8080 www.ambercafe.net Argonne Guest House Building 460 Argonne, IL 60439 630-739-6000 www.anlgh.org Ballydoyle Irish Pub & Restaurant 5157 Main Street Downers Grove, IL 60515 630-969-0600 www.ballydoylepub.com Bd's Mongolian Grill The Promenade Shopping Center Boughton Rd. & I-355 Bolingbrook, IL 60440 630-972-0450 www.gomongo.com Branmor's American Grill 300 Veterans Parkway Bolingbrook, IL 60440 630-226-9926 www.branmors.com Buca di Beppo 90 Yorktown Convenience Center Lombard, IL 60148 630-932-7673 www.bucadibeppo.com California Pizza Kitchen 551 Oakbrook Center Oak Brook, IL 60523 630-571-7800 www.cpk.com Capri Ristorante 5101 Main Street Downers Grove, IL 60516 630-241-0695 www.capriristorante.com Carrabba's Italian Grill
information information at Weldon Spring, Missouri. This site is managed by the U.S. Department of Energy Office of Legacy Management. developed by the former WSSRAP Community Relations Department to provide comprehensive descriptions of key activities that took place throughout the cleanup process The Missouri Department of Conservation (MDC) approved a plan on June 9, 1995, allowing the U.S. Department of Energy (DOE) at the Weldon Spring Site Remedial Action Project (WSSRAP) to excavate nearly 2 million cubic yards of clay material from land in the Weldon Spring Conservation Area. Clay soil from a borrow area was used to construct the permanent disposal facility at the Weldon Spring site. Clay soil was chosen to construct the disposal facility because it has low permeability when
EA-1177: Salvage/Demolition of 200 West Area, 200 East Area, and 300 Area
7: Salvage/Demolition of 200 West Area, 200 East Area, and 7: Salvage/Demolition of 200 West Area, 200 East Area, and 300 Area Steam Plants, Richland, Washington EA-1177: Salvage/Demolition of 200 West Area, 200 East Area, and 300 Area Steam Plants, Richland, Washington SUMMARY This EA evaluates the environmental impacts for the proposal to salvage and demolish the 200 West Area, 200 East Area, and 300 Area steam plants and their associated steam distribution piping equipment, and ancillary facilities at the U.S. Department of Energy Hanford Site in Richland, Washington. PUBLIC COMMENT OPPORTUNITIES None available at this time. DOCUMENTS AVAILABLE FOR DOWNLOAD October 21, 1996 EA-1177: Finding of No Significant Impact Salvage/Demolition of 200 West Area, 200 East Area, and 300 Area Steam Plants October 21, 1996 EA-1177: Final Environmental Assessment
Entanglement Entropy at Large Central Charge
Two-dimensional conformal field theories with a large central charge and a small number of low-dimension operators are studied using the conformal block expansion. A universal formula is derived for the Renyi entropies of N disjoint intervals in the ground state, valid to all orders in a series expansion. This is possible because the full perturbative answer in this regime comes from the exchange of the stress tensor and other descendants of the vacuum state. Therefore, the Renyi entropy is related to the Virasoro vacuum block at large central charge. The entanglement entropy, computed from the Renyi entropy by an analytic continuation, decouples into a sum of single-interval entanglements. This field theory result agrees with the Ryu-Takayanagi formula for the holographic entanglement entropy of a 2d CFT, applied to any number of intervals, and thus can be interpreted as a microscopic calculation of the area of minimal surfaces in 3d gravity.
Hartman, Thomas
Thomas Hartman
v*Zy- i , . v*Zy- i , . r ,v * -i S # Af [, (e- . - o -A tl }r- 0 v-" l^~4~S J l ^-)^ I^U^ck iM clti ^
Area Power Administration Follow-up to Nov. 25, 2008 Transition Meeting Undeveloped Transmission Right-of-Way Western has very little undeveloped transmission right-of-way. There is a 7-mile right- of-way between Folsom, CA and Roseville, CA where Western acquired a 250' wide right-of-way but is only using half of it. Another line could be built parallel to Western's line to relieve congestion in the Sacramento area. In addition, Western has rights-of- way for many transmission lines that could be rebuilt to increase transmission capacity. For example, Western's Tracy-Livermore 230-kV line is a single circuit line but the existing towers could support a double circuit line. These rights-of-way would have to
Earth Tidal Analysis At Marysville Mountain Geothermal Area (1984) | Open
Mountain Geothermal Area (1984) Mountain Geothermal Area (1984) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Earth Tidal Analysis At Marysville Mountain Geothermal Area (1984) Exploration Activity Details Location Marysville Mountain Geothermal Area Exploration Technique Earth Tidal Analysis Activity Date 1984 Usefulness useful DOE-funding Unknown Exploration Basis Determine porosity of the reservoir Notes The response of a confined, areally infinite aquifer to external loads imposed by earth tides is examined. Because the gravitational influence of celestial objects occurs over large areas of the earth, the confined aquifer is assumed to respond in an undrained fashion. Since undrained response is controlled by water compressibility, earth tide response can be
Geothermal Areas | Open Energy Information
Geothermal Areas Geothermal Areas Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Geothermal Areas Geothermal Areas are specific locations of geothermal potential (e.g., Coso Geothermal Area). The base set of geothermal areas used in this database came from the 253 geothermal areas identified by the USGS in their 2008 Resource Assessment.[1] Additional geothermal areas were added, as needed, based on a literature search and on projects listed in the GTP's 2011 database of funded projects. Add.png Add a new Geothermal Resource Area Map of Areas List of Areas Loading map... {"format":"googlemaps3","type":"ROADMAP","types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"limit":2500,"offset":0,"link":"all","sort":[""],"order":[],"headers":"show","mainlabel":"","intro":"","outro":"","searchlabel":"\u2026
With the ever-increasing influx of high-resolution images of the solar surface obtained at a multitude of wavelengths, various processes occurring at small spatial scales have become a greater focus of our attention. Complex small-scale magnetic fields have been reported that appear to have enough stored energy to heat the chromosphere. While significant progress has been made in understanding small-scale phenomena, many specifics remain elusive. We present here a detailed study of a single event of disappearance of a magnetic dipole and associated chromospheric activity. Based on New Solar Telescope H{alpha} data and Hinode photospheric line-of-sight magnetograms and Ca II H images, we report the following. (1) Our analysis indicates that even very small dipoles (elements separated by about 0.''5 or less) may reach the chromosphere and trigger non-negligible chromospheric activity. (2) Careful consideration of the magnetic environment where the new flux is deposited may shed light on the details of magnetic flux removal from the solar surface. We argue that the apparent collision and disappearance of two opposite polarity elements may not necessarily indicate their cancellation (i.e., reconnection, emergence of a 'U' tube, or submergence of {Omega} loops). In our case, the magnetic dipole disappeared by reconnecting with overlying large-scale inclined plage fields. (3) Bright points (BPs) seen in off-band H{alpha} images are very well correlated with the Ca II H BPs, which in turn are cospatial with G-band BPs. We further speculate that, in general, H{alpha} BPs are expected to be cospatial with photospheric BPs; however, a direct comparison is needed to refine their relationship.
Yurchyshyn, V. B.; Goode, P. R.; Abramenko, V. I.; Chae, J.; Cao, W.; Andic, A.; Ahn, K. [Big Bear Solar Observatory, New Jersey Institute of Technology, Big Bear City, CA 92314 (United States)
Taking the 'Large' out of Large Hadron Collider: Computational Breakthrough
Home » News & Publications » News » Science News » Taking the 'Large' out of Large Hadron Collider Taking the 'Large' out of Large Hadron Collider Computational breakthrough hastens modeling of 'tabletop accelerators' August 9, 2010 | Tags: Accelerator Science Contact: Margie Wylie | firstname.lastname@example.com | 510-486-7421 mori1 This 3D simulation shows how laser pulses create plasma wakes that propel electrons forward, much as a surfer is propelled forward by an ocean wave. Laser wakefield acceleration promises electron accelerators that are thousands of times more powerful than, yet a fraction the size of, conventional radio frequency devices. Particle accelerators like the Large Hadron Collider (LHC) at CERN are the big rock stars of high-energy physics-really big. The LHC cost nearly
Three Advantages of the KANATA 1.5-m Telescope as a Powerful Partner for GLAST
KANATA is a 1.5-m optical--near infrared telescope of Hiroshima University, which has been developed for observations of astronomical transients and variables, such as {gamma}-ray bursts, blazars. X-ray transients, and cataclysmic variables. Here, we introduce three characteristics of KANATA with examples of observations, that is, i) high ability for prompt observations, ii) simultaneous optical and infrared observations, and iii) polarimetric observations. Collaborating with GLAST, we are planning to perform follow-up optical--infrared observations of {gamma}-ray sources with KANATA.
Uemura, M.; Yamashita, T.; Kawabata, K. [Astrophysical Science Center, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima, 739-8526 (Japan); Ohsugi, T. [Astrophysical Science Center, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima, 739-8526 (Japan); Department of Physical Science, School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Arai, A.; Nagae, O.; Chiyonobu, S.; Ueda, A.; Fukazawa, Y.; Mizuno, T.; Katagiri, H.; Takahashi, H. [Department of Physical Science, School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Hayashi, T. [Department of Education, Hiroshima University, Kagamiyama 1-1-1, Higashi-Hiroshima 739-8524 (Japan); Okita, K.; Yoshida, M.; Yanagisawa, K. [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Kamogata Okayama, 719-0232 (Japan); Sato, S.; Kino, M.; Kitagawa, M. [Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan); Sadakane, K. [Astronomical Institute, Osaka Kyoiku University, Asahigaoka, Kashiwara, Osaka 582-8582 (Japan)
THE NUCLEAR SPECTROSCOPIC TELESCOPE ARRAY (NuSTAR) HIGH-ENERGY X-RAY MISSION
The Nuclear Spectroscopic Telescope Array (NuSTAR) mission, launched on 2012 June 13, is the first focusing high-energy X-ray telescope in orbit. NuSTAR operates in the band from 3 to 79 keV, extending the sensitivity of focusing far beyond the {approx}10 keV high-energy cutoff achieved by all previous X-ray satellites. The inherently low background associated with concentrating the X-ray light enables NuSTAR to probe the hard X-ray sky with a more than 100-fold improvement in sensitivity over the collimated or coded mask instruments that have operated in this bandpass. Using its unprecedented combination of sensitivity and spatial and spectral resolution, NuSTAR will pursue five primary scientific objectives: (1) probe obscured active galactic nucleus (AGN) activity out to the peak epoch of galaxy assembly in the universe (at z {approx}< 2) by surveying selected regions of the sky; (2) study the population of hard X-ray-emitting compact objects in the Galaxy by mapping the central regions of the Milky Way; (3) study the non-thermal radiation in young supernova remnants, both the hard X-ray continuum and the emission from the radioactive element {sup 44}Ti; (4) observe blazars contemporaneously with ground-based radio, optical, and TeV telescopes, as well as with Fermi and Swift, to constrain the structure of AGN jets; and (5) observe line and continuum emission from core-collapse supernovae in the Local Group, and from nearby Type Ia events, to constrain explosion models. During its baseline two-year mission, NuSTAR will also undertake a broad program of targeted observations. The observatory consists of two co-aligned grazing-incidence X-ray telescopes pointed at celestial targets by a three-axis stabilized spacecraft. Deployed into a 600 km, near-circular, 6 Degree-Sign inclination orbit, the observatory has now completed commissioning, and is performing consistent with pre-launch expectations. NuSTAR is now executing its primary science mission, and with an expected orbit lifetime of 10 yr, we anticipate proposing a guest investigator program, to begin in late 2014.
Harrison, Fiona A.; Cook, W. Rick; Forster, Karl; Grefenstette, Brian W.; Madsen, Kristin K.; Mao, Peter H.; Miyasaka, Hiromasa [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Craig, William W.; Pivovaroff, Michael J. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Christensen, Finn E. [DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Hailey, Charles J.; Koglin, Jason E.; Mori, Kaya [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Zhang, William W. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Boggs, Steven E. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Stern, Daniel; Kim, Yunjin [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Giommi, Paolo; Perri, Matteo [ASI Science Data Center, c/o ESRIN, via G. Galilei, I-00044 Frascati (Italy); Kitaguchi, Takao, E-mail: firstname.lastname@example.com [INAF-Osservatorio Astronomico di Roma, via di Frascati 33, I-00040 Monteporzio (Italy); and others
Western Area Power Administration Customer Meeting The meeting will begin at 12:30 pm MST We have logged on early for connectivity purposes Please stand-by until the meeting begins Please be sure to call into the conference bridge at: 888-989-6414 Conf. Code 60223 If you have connectivity issues, please contact: 866-900-1011 1 Introduction ď'— Welcome ď'— Introductions ď'— Purpose of Meeting â—¦ Status of the SLCA/IP Rate â—¦ SLCA/IP Marketing Plan â—¦ Credit Worthiness Policy â—¦ LTEMP EIS update â—¦ Access to Capital ď'— Handout Materials http://www.wapa.gov/crsp/ratescrsp/default.htm 2 SLCA/IP Rate 3 1. Status of Repayment 2. Current SLCA/IP Firm Power Rate (SLIP-F9) 3. Revenue Requirements Comparison Table 4.SLCA/IP Rate 5. Next Steps
Detection of H2 Emission from Mira B in UV Spectra from the Hubble Space Telescope
We present ultraviolet spectra of Mira's companion star from the Space Telescope Imaging Spectrograph (STIS) instrument on board the Hubble Space Telescope (HST). The companion is generally assumed to be a white dwarf surrounded by an accretion disk fed by Mira's wind, which dominates the UV emission from the system. The STIS UV spectrum is dominated by numerous, narrow H2 lines fluoresced by H I Ly-alpha, which were not detected in any of the numerous observations of Mira B by the International Ultraviolet Explorer (IUE). The high temperature lines detected by IUE (e.g., C IV 1550) still exist in the STIS spectrum but with dramatically lower fluxes. The continuum fluxes in the STIS spectra are also much lower, being more than an order of magnitude lower than ever observed by IUE, and also an order of magnitude lower than fluxes observed in more recent HST Faint Object Camera objective prism spectra from 1995. Thus, the accretion rate onto Mira B was apparently much lower when STIS observed the star, and this change altered the character of Mira B's UV spectrum.
Brian E. Wood; Margarita Karovska; Warren Hack
We report on the microscopic surface structure of carbon-fiber-reinforced silicon carbide (C/SiC) composite mirrors that have been improved for the Space Infrared Telescope for Cosmology and Astrophysics (SPICA) and other cooled telescopes. The C/SiC composite consists of carbon fiber, silicon carbide, and residual silicon. Specific microscopic structures are found on the surface of the bare C/SiC mirrors after polishing. These structures are considered to be caused by the different hardness of those materials. The roughness obtained for the bare mirrors is 20 nm rms for flat surfaces and 100 nm rms for curved surfaces. It was confirmed that a SiSiC slurry coating is effective in reducing the roughness to 2 nm rms. The scattering properties of the mirrors were measured at room temperature and also at 95 K. No significant change was found in the scattering properties through cooling, which suggests that the microscopic surface structure is stable with changes in temperature down to cryogenic values. The C/SiC ...
Enya, Keigo; Kaneda, Hidehiro; Onaka, Takashi; Ozaki, Tuyoshi; Kume, Masami
The VERITAS Upgraded Telescope-Level Trigger Systems: Technical Details and Performance Characterization
VERITAS is an array of imaging atmospheric Cherenkov telescopes sensitive to gamma rays in the energy range between 85 GeV and 30 TeV. The instrument underwent an upgrade of the camera triggers in November 2011. The new systems use 400 MHz Xilinix Virtex-5 FPGAs for the pixel neighbor coincidence logic necessary to produce a camera-level trigger. The upgraded systems are capable of time-aligning individual triggering pixels to within ~0.2 nanoseconds, allowing for an operational pixel-to-pixel coincidence window of ~5 nanoseconds. This reduced coincidence window provides improved rejection of night-sky background (NSB) which permits a reduction of the energy threshold at the trigger level. The use of FPGAs allows for the future implementation of a topological trigger capable of discriminating events based on an image moment analysis of a bit-wise hit pattern. As part of the commissioning phase for the trigger upgrade, the hardware was initially installed in a single telescope in "parallel" to the (then) curre...
Zitzer, Benjamin
Polarimeter Receiver Prototyping and Testing for the South Pole Telescope Upgrade
Experimental evidence has so far been supportive for the inflationary Big Bang model of cosmology, while imposing other mysteries, such as the fact that dark matter and dark energy actually consist of 95 % of the observable universe. The forthcoming upgrade of the South Pole Telescope, planned for 2010, will include a polarimeter with increased sensitivity. Measurements of the CMB polarization anisotropy to a high accuracy will describe the angular power spectrum of the B-mode polarization, which will help unravel some of the mysteries. We prototype and test a digital frequency multiplexed readout system for the SPT upgrade. The digital system has the advantage of being able to reconstruct the phase of the signals. We characterize the performance of the readout and we compare it to the theoretical expectations. The noise is found to be statistically insignificant (insert quantitative proof), and the system performs as expected, significantly better than the previous implementation. We conclude that the digital fMux readout system should be sent to the South Pole Telescope. 1
Constantinos Melachrinos
The forward inelastic telescope T2 for the TOTEM experiment at the LHC
The TOTEM Experiment will measure the total pp cross-section with the luminosity-independent method and study elastic and diffractive scattering at the LHC. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the interaction point IP5, two tracking telescopes, T1 and T2, will be installed on each side in the pseudorapidity region $3.1 \\leq |\\eta| \\leq 6.5$ and Roman Pot stations will be placed at distances of 147 m and 220 m from the Interaction Point 5 (IP5). The triple Gas Electron Multiplier (GEM) technology has been chosen by the collaboration for its T2 telescope which will provide charged track reconstruction in the rapidity range $5.3 < \\eta < 6.5$ and a fully inclusive trigger for diffractive events. Results from the preliminary tests on the prototypes of the TOTEM Triple GEM detectors up to the data taking during the first pp collisions at the LHC will be described in this thesis.
Oliveri, Eraldo; Turini, Nicola
NETL: Industrial Capture and Storage (ICCS): Area 1
ICCS Area 1 ICCS Area 1 Major Demonstrations Industrial Capture and Storage (ICCS): Area 1 The Large-Scale Industrial CCS Projects (Area 1) are managed by NETL under the Major Demonstrations Program. In October 2009, the U.S. Department of Energy announced the selection of 12 Large-Scale projects intended to capture CO2 from industrial sources for storage or beneficial use. Read more! These Phase I projects were cost-shared collaborations between the government and industry to increase investment in clean industrial technologies and sequestration projects. The Phase I duration of each project selected was approximately seven months. On June 10, 2010, DOE selected three projects from Phase I to enter into Phase 2 for design, construction, and operation. Potential additional applications for funding of large-scale industrial carbon capture and storage projects are pending further clarification and review. Collapse Text
S>An improved area radiation dose monitor is designed which is adapted to compensate continuously for background radiation below a threshold dose rate and to give warning when the dose integral of the dose rate of an above-threshold radiation excursion exceeds a selected value. This is accomplished by providing means for continuously charging an ionization chamber. The chamber provides a first current proportional to the incident radiation dose rate. Means are provided for generating a second current including means for nulling out the first current with the second current at all values of the first current corresponding to dose rates below a selected threshold dose rate value. The second current has a maximum value corresponding to that of the first current at the threshold dose rate. The excess of the first current over the second current, which occurs above the threshold, is integrated and an alarm is given at a selected integrated value of the excess corresponding to a selected radiation dose. (AEC)
Manning, F.W.; Groothuis, S.E.; Lykins, J.H.; Papke, D.M.
Power System Aggregate Load Area Dynamic Modeling by Learning Based on WAMS
This paper is concerned with an investigation of a methodology using intelligent learning techniques based on WAMS to construct power system load area model. An aggregate load area dynamic model (ALADM) is proposed to represent large area loads of power ... Keywords: ALADM, Genetic algorithm, Load area modeling, Power system, Recursive least squares
Huimin Yang; Jinyu Wen
Combining Balancing Areas' Variability: Impacts on Wind Integration in the Western Interconnection
This paper investigates the potential impact of balancing area cooperation on a large-scale in the Western Electricity Coordinating Council (WECC).
Milligan, M.; Kirby, B.; Beuning, S.
Large Consistent Geometric Landmark Maps
The autonomous operation of an intelligent service robot in practical applications requires that the robot builds up a map of the environment by itself, even for large environments like supermarkets. This paper presents a solution to the problem of building ...
Wolfgang D. Rencken; Wendelin Feiten; Martin Soika
Lightning Safety and Large Stadiums
When lightning threatens an outdoor activity, it is usually postponed so that people may seek a safe location. When lightning threatens a large outdoor stadium, the game or event itself is usually postponed, but it is often difficult to ensure ...
Joel Gratz; Erik Noble
An Efficient Strategy to Select Targets for Gas-Dynamical Measurements of Black Hole Masses Using the Hubble Space Telescope
Gas-dynamical studies using the Hubble Space Telescope are an integral component for future progress in the search for massive black holes in galactic nuclei. Here we present an extensive set of gas rotation curves obtained with the Space Telescope Imaging Spectrograph for the central regions of 23 disk galaxies. We find that the bulges of randomly selected, nearby spiral and S0 galaxies generally do not contain well-defined gaseous disks. Only 15%-20% of disk galaxies have regular, symmetric velocity fields useful for dynamical analysis. Through comparison of the kinematics with Hubble Space Telescope images of the nuclear regions, we show that the probability of success can be significantly boosted by preselecting objects whose central dust lanes follow a well-ordered, circularly symmetric pattern. The dust morphology can be ascertained efficiently by visual inspection of unsharp-masked images.
Luis C. Ho; Marc Sarzi; Hans-Walter Rix; Joseph C. Shields; Greg Rudnick; Alexei V. Filippenko; Aaron J. Barth
Ho, L C; Rix, H W; Shields, J C; Rudnick, G; Filippenko, A V; Barth, A J; Ho, Luis C.; Sarzi, Marc; Rix, Hans-Walter; Shields, Joseph C.; Rudnick, Greg; Filippenko, Alexei V.; Barth, Aaron J.
SLAC National Accelerator Laboratory - Scientific Computing
data from the Large Area Telescope, the main instrument on the orbiting Fermi Gamma-ray Space Telescope. SLAC staff also contributes to the software that makes Fermi LAT...
Inquiring Minds
by Gran Sasso and Heidelberg to operate Ge detectors in liquid nitrogen. GLAST: Gamma-ray Large Area Space Telescope. A proposed orbiting telescope for high-energy gamma rays....
Program Areas | National Security | ORNL
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Body Area Networks: A Survey
Advances in wireless communication technologies, such as wearable and implantable biosensors, along with recent developments in the embedded computing area are enabling the design, development, and implementation of body area networks. This class of ... Keywords: body area networks, survey, wireless sensor networks
Min Chen; Sergio Gonzalez; Athanasios Vasilakos; Huasong Cao; Victor C. Leung
Direct Thin Film Path to Low Cost, Large Area III-V ...
Energy Analysis; Energy Storage; Geothermal; Hydrogen and Fuel Cell; Hydropower, Wave and Tidal; Industrial Technologies; Solar Photovoltaic; ... ...
Large area silicon sheet by EFG. Annual progress report, October 29, 1975--September 30, 1976
At the end of one year the program is on schedule. EFG ribbon growth system JPL No. 2 is being used to perform meaningful growth rate and ribbon thickness experiments. The new, wide ribbon growth system is in operation. A theoretical study of stresses in ribbons is reported. EFG ribbons have been observed to exhibit a characteristic defect structure which is orientation dependent in the early stages of growth.
Morrison, A.D.; Ravi, K.V.; Hari Rao, C.V.; Surek, T.; Bliss, D.F.; Garone, L.C.; Hogencamp, R.W.
Enabling Low–Cost Large–Area OPV Solar Power - Programmaster ...
Plextronics, Inc. is helping seed the renewable energy OPV market by .... Stress Relaxation in GaN Epilayers Grown by MOCVD with Indium Surfactant ... Tight Binding and LCAO Methods for Tin Oxide Deposited by Chemical Vapour ...
Direct Thin Film Path to Low Cost, Large Area III-V Photovoltaics
A team of Berkeley Lab researchers has invented the first vapor-liquid-solid (VLS) growth technology yielding III-V photovoltaics. The photovoltaics ...
Large area silicon sheet by EFG. Fourth quarterly report, October 1--December 31, 1976
During this reporting period, 5 cm wide ribbons, some with no measurable residual stress, have been grown at speeds up to 5 cm/min. The relationship between residual stress and system vertical temperature gradient was further defined. The problems associated with the purity of the ribbons are being investigated. The influence of light on the recombination characteristics of defects in the ribbons has been investigated. Procedures and results are reported.