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Sample records for glast lat tracker

  1. Environmental Tests of the Flight GLAST LAT Tracker Towers

    SciTech Connect

    Bagagli, R.; Baldini, L.; Bellazzini, R.; Barbiellini, G.; Belli, F.; Borden, T.; Brez, A.; Brigida, M.; Caliandro, G.A.; Cecchi, C.; Cohen-Tanugi, J.; Angelis, A.De; Drell, P.; Favuzzi, C.; Fusco, P.; Gargano, F.; Germani, S.; Giglietto, N.; Giordano, F.; Goodman, J.; Himel, T.

    2008-03-12

    The Gamma-ray Large Area Space telescope (GLAST) is a gamma-ray satellite scheduled for launch in 2008. Before the assembly of the Tracker subsystem of the Large Area Telescope (LAT) science instrument of GLAST, every component (tray) and module (tower) has been subjected to extensive ground testing required to ensure successful launch and on-orbit operation. This paper describes the sequence and results of the environmental tests performed on an engineering model and all the flight hardware of the GLAST LAT Tracker. Environmental tests include vibration testing, thermal cycles and thermal-vacuum cycles of every tray and tower as well as the verification of their electrical performance.

  2. Environmental Test Activity on the Flight Modules of the GLAST LAT Tracker

    SciTech Connect

    Brigida, M.; Caliandro, A.; Favuzzi, C.; Fusco, P.; Gargano, F.; Giglietto, N.; Giordano, F.; Loparco, F.; Marangelli, B.; Mazziotta, M.N.; Mirizzi, N.; Raino, S.; Spinelli, P.; /Bari U. /INFN, Bari

    2007-02-15

    The GLAST Large Area Telescope (LAT) is a gamma-ray telescope consisting of a silicon micro-strip detector tracker followed by a segmented CsI calorimeter and covered by a segmented scintillator anticoincidence system that will search for {gamma}-rays in the 20 MeV-300 GeV energy range. The results of the environmental tests performed on the flight modules (towers) of the Tracker are presented. The aim of the environmental tests is to verify the performance of the silicon detectors in the expected mission environment. The tower modules are subjected to dynamic tests that simulate the launch environment and thermal vacuum test that reproduce the thermal gradients expected on orbit. The tower performance is continuously monitored during the whole test sequence. The environmental test activity, the results of the tests and the silicon tracker performance are presented.

  3. The GLAST LAT Instrument Science Operations Center

    NASA Astrophysics Data System (ADS)

    Cameron, Robert A.; LAT ISOC, GLAST

    2006-12-01

    The Gamma-ray Large Area Space Telescope (GLAST) is scheduled for launch in late 2007. The major science instrument on GLAST is the Large Area Telescope (LAT). Operations support and science data processing for the LAT instrument on GLAST will be performed by the LAT Instrument Science Operations Center (ISOC) at the Stanford Linear Accelerator Center (SLAC). The ISOC supports GLAST mission operations in cooperation with other GLAST mission ground system elements and supports the science research activities of the LAT collaboration. The ISOC will be responsible for monitoring the health and safety of the LAT, preparing command loads for the LAT, maintaining and updating embedded flight software which controls the LAT detector and data acquisition flight hardware, maintaining the operating configration of the LAT and its calibration, and applying event reconstruction processing to downlinked LAT data to recover information about detected gamma-ray photons. The SLAC computer farm will be used to process the large volume of LAT event data and generate science products to be made available to the LAT collaboration through the ISOC and to the broader scientific community through the GLAST Science Support Center at GSFC. Science operations in the ISOC will optimize the performance of the LAT and oversee automated science processing of LAT data to detect and monitor transient gamma-ray sources. We describe the use of collaboration-wide data challenges and service challenges to test and exercise LAT data processing and science operations before launch. This work is supported by Stanford University and the Stanford Linear Accelerator Center (SLAC) under DoE contract number DE-AC03-76SFO0515. Non-US sources of funding also support the efforts of GLAST LAT collaborators in France, Italy, Japan, and Sweden.

  4. The GLAST LAT Instrument Science Operations Center

    NASA Astrophysics Data System (ADS)

    Cameron, Robert A.

    2007-07-01

    The Gamma-ray Large Area Space Telescope (GLAST) is scheduled for launch in late 2007. Operations support and science data processing for the Large Area Telescope (LAT) instrument on GLAST will be provided by the LAT Instrument Science Operations Center (ISOC) at the Stanford Linear Accelerator Center (SLAC). The ISOC supports GLAST mission operations in conjunction with other GLAST mission ground system elements and supports the research activities of the LAT scientific collaboration. The ISOC will be responsible for monitoring the health and safety of the LAT, preparing command loads for the LAT, maintaining embedded flight software which controls the LAT detector and data acquisition flight hardware, maintaining the operating configuration of the LAT and its calibration, and applying event reconstruction processing to down-linked LAT data to recover information about detected gamma-ray photons. The SLAC computer farm will be used to process LAT event data and generate science products, to be made available to the LAT collaboration through the ISOC and to the broader scientific community through the GLAST Science Support Center at NASA/GSFC. ISOC science operations will optimize the performance of the LAT and oversee automated science processing of LAT data to detect and monitor transient gamma-ray sources.

  5. The GLAST LAT Instrument Science Operations Center

    NASA Astrophysics Data System (ADS)

    Cameron, Robert A.; Silva, E. do Couto e.; Dubois, R.; LAT ISOC, GLAST

    2006-09-01

    Operations support and science data processing for the Large Area Telescope (LAT) instrument on the Gamma-ray Large Area Space Telescope (GLAST) will be provided by the LAT Instrument Science Operations Center (ISOC) at the Stanford Linear Accelerator Center (SLAC). The ISOC supports GLAST mission operations in cooperation with other GLAST mission ground system elements and supports the science activities of the LAT collaboration. The ISOC will be responsible for monitoring the health and safety of the LAT, preparing command sequences for the LAT, maintaining and updating embedded flight software which controls the LAT detector and data acquisition flight hardware, maintaining the LAT configuration and calibration, and applying event reconstruction processing to downlinked LAT data to recover information about detected gamma-ray photons. The SLAC computer farm will be used to process the large volume of LAT event data and generate science products to be made available to the LAT collaboration through the ISOC and to the broader scientific community through the GLAST Science Support Center at GSFC. Science operations in the ISOC will optimize the performance of the LAT and oversee automated science processing of LAT data to detect and monitor transient gamma-ray sources. We describe the use of collaboration-wide data challenges to test and exercise LAT data processing before launch.

  6. The GLAST Mission, LAT and GRBs

    SciTech Connect

    Omodei, Nicola; /INFN, Pisa

    2006-04-05

    The GLAST Large Area Telescope (LAT) is the next generation satellite experiment for high-energy gamma-ray astronomy. It is a pair conversion telescope built with a plastic anticoincidence shield, a segmented CsI electromagnetic calorimeter, and the largest silicon strip tracker ever built. It will cover the energy range from 30 MeV to 300 GeV, shedding light on many issues left open by its predecessor EGRET. One of the most exciting science topics is the detection and observation of gamma-ray bursts (GRBs). In this paper we present the work done so far by the GRB LAT science group in studying the performance of the LAT detector to observe GRBs.We report on the simulation framework developed by the group as well as on the science tools dedicated to GRBs data analysis. We present the LAT sensitivity to GRBs obtained with such simulations, and, finally, the general scheme of GRBs detection that will be adopted on orbit.

  7. Automated Science Processing for GLAST LAT Data

    SciTech Connect

    Chiang, James

    2007-07-12

    Automated Science Processing (ASP) will be performed by the GLAST Large Area Telescope (LAT) Instrument Science Operations Center (ISOC) on data from the satellite as soon as the Level 1 data are available in the ground processing pipeline. ASP will consist of time-critical science analyses that will facilitate follow-up and multi-wavelength observations of transient sources. These analyses include refinement of gamma-ray burst (GRB) positions, timing, flux and spectral properties, off-line searches for untriggered GRBs and gamma-ray afterglows, longer time scale monitoring of a standard set of sources (AGNs, X-ray binaries), and searches for previously unknown flaring sources in the LAT band. We describe the design of ASP and its scientific products; and we show results of a prototype implementation, driven by the standard LAT data processing pipeline, as applied to simulated LAT and GBM data.

  8. Automated Science Processing for GLAST LAT Data

    SciTech Connect

    Chiang, James; Carson, Jennifer; Focke, Warren; /SLAC

    2007-10-15

    Automated Science Processing (ASP) will be performed by the GLAST Large Area Telescope (LAT) Instrument Science Operations Center (ISOC) on data from the satellite as soon as the Level 1 data are available in the ground processing pipeline. ASP will consist of time-critical science analyses that will facilitate follow-up and multi-wavelength observations of transient sources. These analyses include refinement of gamma-ray burst (GRB) positions, timing, flux and spectral properties, off-line searches for untriggered GRBs and gamma-ray afterglows, longer time scale monitoring of a standard set of sources (AGNs, X-ray binaries), and searches for previously unknown flaring sources in the LAT band. We describe the design of ASP and its scientific products; and we show results of a prototype implementation, driven by the standard LAT data processing pipeline, as applied to simulated LAT and GBM data.

  9. Analysis of Burst Observations by GLAST'S LAT

    SciTech Connect

    Band, D

    2003-12-17

    Analyzing data from GLAST's Large Area Telescope (LAT) will require sophisticated techniques. The PSF and effective area are functions of both photon energy and the position in the field-of-view. During most of the mission the observatory will survey the sky continuously and thus the LAT will detect each count from a source at a different detector orientation; each count requires its own response function. The likelihood as a function of celestial position and photon energy will be the foundation of the standard analysis techniques. However the 20 MeV-300 GeV emission at the time of the {approx}100 keV burst emission (timescale of {approx}10 s) can be isolated and analyzed because essentially no non-burst counts are expected within a PSF radius of the burst location during the burst. Both binned and unbinned (in energy) spectral fitting will be possible. Longer timescale afterglow emission will require the likelihood analysis that will be used for persistent sources.

  10. GLAST LAT And Pulsars: What Do We Learn from Simulations?

    SciTech Connect

    Razzano, Massimiliano; Harding, Alice K.; /NASA, Goddard

    2007-10-24

    Gamma-ray pulsars are among the best targets for the Large Area Telescope (LAT) aboard the GLAST mission. The higher sensitivity, time and energy resolution of the LAT will provide data of fundamental importance to understand the physics of these fascinating objects. Powerful tools for studying the LAT capabilities for pulsar science are the simulation programs developed within the GLAST Collaboration. Thanks to these simulations it is possible to produce a detailed distribution of gamma-ray photons in energy and phase that can be folded through the LAT Instrument Response Functions (IRFs). Here we present some of the main interesting results from the simulations developed to study the discovery potential of the LAT. In particular we will focus on the capability of the LAT to discover new radio-loud gamma-ray pulsars, on the discrimination between Polar Cap and Outer Gap models, and on the LAT pulsar sensitivity.

  11. GeV flares observations with GLAST LAT

    SciTech Connect

    Galli, A.; Omodei, N.; Piro, L.

    2007-07-12

    Early X-ray afterglow observations show that X-ray flares are very common features in GRB light curves. X-ray flares may reflect long duration central engine activity. The delayed flare photons are expected to interact with relativistic electrons by Inverse Compton giving delayed high energy counterparts that potentially will be detected by GLAST LAT, which could observe GRB from 20 MeV to more than 300 GeV. The nature oh high energy spectral components from GRB detected by EGRET is still debated. Observations with GLAST LAT will give useful information to constrain the origin of X-ray flares. In this work we simulate a set of possible GeV emitting flares in the context of External Shock model to study the capability of GLAST LAT to detect GeV flares at different intensities and durations.

  12. Performance of the Integrated Tracker Towers of the GLAST Large Area Telescope

    SciTech Connect

    Brigida, M.; Caliandro, A.; Favuzzi, C.; Fusco, P.; Gargano, F.; Giglietto, N.; Giordano, F.; Loparco, F.; Marangelli, B.; Mazziotta, M.N.; Mirizzi, N.; Raino, S.; Spinelli, P.; /Bari U. /INFN, Bari

    2007-02-15

    The GLAST Large Area Telescope (LAT) is a high energy gamma ray observatory, mounted on a satellite that will be own in 2007. The LAT tracker consists of an array of tower modules, equipped with planes of silicon strip detectors (SSDs) interleaved with tungsten converter layers. Photon detection is based on the pair conversion process; silicon strip detectors will reconstruct tracks of electrons and positrons. The instrument is actually being assembled. The first towers have been already tested and integrated at Stanford Linear Accelerator Center (SLAC). An overview of the integration stages of the main components of the tracker and a description of the pre-launch tests will be given. Experimental results on the performance of the tracker towers will be also discussed.

  13. Lessons Learned During Construction and Test of the GLAST Large Area Telescope Tracker

    SciTech Connect

    Latronico, L.; /INFN, Pisa

    2005-08-09

    The GLAST Large Area Telescope (LAT) is a satellite gamma-ray observatory designed to explore the sky in the energy range 20MeV {approx_equal} 300GeV, a region populated by emissions from the most energetic and mysterious objects in the cosmos, like black holes, AGNs, supernovae, gamma-ray bursters. The silicon-strip tracker is the heart of the photon detection system, and with its 80 m{sup 2} of surface and almost 1M channels is one of the largest silicon tracker ever built. Its construction, to be completed by 2006, and the stringent requirements from operation in space, represent a major technological challenge. Critical design, technology and system engineering issues are addressed in this paper, as well as the approach being followed during construction, test and qualification of the LAT silicon tracker.

  14. The Search for Milky Way Halo Substructure WIMP Annihilations Using the GLAST LAT

    SciTech Connect

    Wai, Larry; /SLAC

    2007-02-05

    The GLAST LAT Collaboration is one among several experimental groups, covering a wide range of approaches, pursuing the search for the nature of dark matter. The GLAST LAT has the unique ability to find new sources of high energy gamma radiation emanating directly from WIMP annihilations in situ in the universe. Using it's wide band spectral and full sky spatial capabilities, the GLAST LAT can form ''images'' in high energy gamma-rays of dark matter substructures in the gamma-ray sky. We describe a preliminary feasibility study for indirect detection of milky way dark matter satellites using the GLAST LAT.

  15. Studying Gamma-Ray Blazars With the GLAST-LAT

    SciTech Connect

    Lott, B.; Carson, J.; Madejski, G.; Ciprini, S.; Dermer, C.D.; Giommi, P.; Lonjou, V.; Reimer, A.; /Stanford U., HEPL /KIPAC, Menlo Park

    2007-11-13

    Thanks to its sensitivity (4 10{sup -9} ph (E> 100 MeV) cm{sup -2} s{sup -1} for one year of observation), the GLAST LAT should detect many more (over a thousand) gamma-ray blazars than currently known. This large blazar sample will enable detailed population studies to be carried out. Moreover, the LAT large field-of-view combined with the scanning mode will provide a very uniform exposure over the sky, allowing a constant monitoring of several tens of blazars and flare alerts to be issued. This poster presents the LAT performance relevant to blazar studies, more particularly related to timing and spectral properties. Major specific issues regarding the blazar phenomenon that the LAT data should shed light on thanks to these capabilities will be discussed, as well as the different approaches foreseen to address them. The associated data required in other bands, to be collected in contemporaneous/simultaneous multiwavelength campaigns are mentioned as well.

  16. Analysis of Burst Observations by GLAST's LAT Detector

    NASA Technical Reports Server (NTRS)

    Band, David L.; Digel, Seth W.

    2003-01-01

    Analyzing data from GLAST's Large Area Telescope (LAT) will require sophisticated techniques. The PSF and effective area are functions of both photon energy and the position in the field-of-view. During most of the mission the observatory will survey the sky continuously and thus the LAT will detect each count from a source at a different detector orientation; each count requires its own response function! The likelihood as a function of celestial position and photon energy will be the foundation of the standard analysis techniques. However the 20 MeV-300 GeV emission at the time of the approx.100 keV burst emission (timescale of approx.10 s) can be isolated and analyzed because essentially no non-burst counts are expected within a PSF radius of the burst location during the burst. Both binned and unbinned (in energy) spectral fitting will be possible. Longer timescale afterglow emission will require the likelihood analysis that will be used for persistent sources.

  17. Performance of the GLAST/LAT for the Observation of GRB Spectra

    SciTech Connect

    Komin, Nukri; Piron, Frederic

    2007-07-12

    GLAST is a gamma-ray mission which will be launched in autumn 2007. It is equipped with the GLAST Burst Monitor (GBM) which detects GRBs with high reliability and provides a position and energy spectrum in the range between 10 keV and 25 MeV. The Large Area Telescope (LAT) will observe photons with energies from 20 MeV up to more than 300 GeV.Here we present a systematic study of the performance of the LAT for the reconstruction of the energy spectrum of Gamma-Ray Bursts (GRBs), based on the simulation of 1 year of data taking. We focus on deviations from a pure power-law photon spectrum (exponential cut-offs). This feature can provide insight in the particle acceleration mechanisms at work in GRBs; and it can be used to probe the Extra-Galactic Background Light.

  18. The Synergy between the LAT and GBM in GLAST's Study of Gamma-Ray Bursts

    SciTech Connect

    Band, David L.

    2007-07-12

    Using semi-analytic calculations I characterize the gamma-ray bursts to which GLAST's LAT and GBM detectors will be sensitive. The thresholds of both instruments are at approximately the same {nu}f{nu} {proportional_to} E2N(E) values, i.e., the thresholds can be connected by an E-2 spectrum. Therefore simultaneous detections by both instruments will be biased towards spectral components flatter than E-2.

  19. The Synergy between the LAT and GBM in GLAST's Study of Gamma-Ray Bursts

    NASA Technical Reports Server (NTRS)

    Band, David L.

    2007-01-01

    Using semi-analytic calculations I characterize the gamma-ray bursts to which GLAST's LAT and GBM detectors will be sensitive. The thresholds of both instruments are at approximately the same vfv proportional to E(sup 2)N(E) values, i.e., the thresholds can be connected by an E(sup -2) spectrum. Therefore simultaneous detections by both instruments will be biased towards spectral components flatter than E(sup -2).

  20. First Results From GLAST-LAT Integrated Towers Cosmic Ray Data Taking And Monte Carlo Comparison

    SciTech Connect

    Brigida, M.; Caliandro, A.; Favuzzi, C.; Fusco, P.; Gargano, F.; Giordano, F.; Giglietto, N.; Loparco, F.; Marangelli, B.; Mazziotta, M.N.; Mirizzi, N.; Raino, S.; Spinelli, P.; /Bari U. /INFN, Bari

    2007-02-15

    GLAST Large Area Telescope (LAT) is a gamma ray telescope instrumented with silicon-strip detector planes and sheets of converter, followed by a calorimeter (CAL) and surrounded by an anticoincidence system (ACD). This instrument is sensitive to gamma rays in the energy range between 20 MeV and 300 GeV. At present, the first towers have been integrated and pre-launch data taking with cosmic ray muons is being performed. The results from the data analysis carried out during LAT integration will be discussed and a comparison with the predictions from the Monte Carlo simulation will be shown.

  1. The GLAST Mission: Using Scintillating Fibers as Both the Tracker and the Calorimeter

    NASA Technical Reports Server (NTRS)

    Fisman, Gerald J.

    1997-01-01

    The Gamma-Ray Large Area Space Telescope (GLAST) has been identified as the next major NASA mission in gamma-ray astronomy. It will operate at energies above 20 MeV to study some of the most energetic objects in the Universe. While the baseline tracker detector for GLAST during the study phase is based on silicon strips, we believe that scintillating fibers have considerable advantages for this purpose. Among the performance advantages are: larger effective area, better angular resolution at low energies and larger field of view. Practical advantages include: lower cost, the use of a common technology for both the tracker and the calorimeter, lower power consumption, and a simplified thermal design. Several alternative readout schemes for the fibers are under study.

  2. Gamma Ray Bursts And Data Challenge One: Searching GRB in One Week of Simulated GLAST LAT Data

    SciTech Connect

    Longo, F.; Omodei, N.; Band, D.; Bonnell, J.T.; Brigida, M.; Cohen-Tanugi, J.; Giannitrapani, R.; Kamae, T.; Norris, J.P.; Winai, M.; /Trieste U. /INFN, Trieste /Siena U. /INFN, Pisa /NASA, Goddard /Bari U. /INFN, Bari /SLAC /Udine U.

    2006-02-22

    GLAST (Gamma-ray Large Area Space Telescope) is a gamma-ray astronomy mission that will be launched in mid 2007. The main instrument is the LAT (Large Area Telescope), a pair conversion telescope with sensitivity in the range 20 MeV-300 GeV. Data Challenge One (DC1) was the simulation of one week of observation of the entire gamma-ray sky by the LAT detector. the simulated data was similar to the real data, which allowed for the development of scientific software. In this paper they present the GRB simulations and the detection algorithms developed by the GLAST GRB and Solar Flare Science Team.

  3. Glast

    NASA Astrophysics Data System (ADS)

    Bloom, E. D.

    Recent results from the Energetic Gamma-Ray Experiment Telescope (EGRET) aboard the Compton Observatory have generated strong interest in space based high-energy (Egamma greater than 10 MeV) gamma ray astronomy. This science has wetted the authors' curiosity of what might be observed with an instrument having considerably more capability than EGRET, if such a device were practical in these fiscally difficult times. Advances in silicon technology over the past decade, and the resulting rapid drop in costs, encourage the development of a dramatically new type of high-energy gamma ray space telescope based on silicon strip technology. The GLAST team (GLAST stands for Gamma-ray Large Area Space Telescope) has been working for the past two years on the design of such an instrument, and the development of the silicon strip hardware and readout electronics needed to realize this design. As in previous high-energy instruments, GLAST is a pair spectrometer backed by a total absorption electro-magnetic shower counter. Measurement of the energy and direction of the induced electro-magnetic shower provides information about the energy and direction of the incident gamma-ray. However, due to the flexibility and relatively low cost of the silicon strip technology, the telescope has about a factor of 10 increase in effective area over EGRET, and about a factor of 5 increase in field of view. At the same time, the GLAST design is calculated to have much better point source sensitivity, and to have an energy range of 10 MeV less than Egamma less than 300 GeV. Due to the economics of silicon technology, along with weight, and size savings compared to gas based detector technology, the authors estimate that this instrument can be built and flown as a Delta II mission. Thus, GLAST would easily fit into the NASA intermediate category with an estimated total cost of about $200 million.

  4. GRB Simulations in GLAST

    SciTech Connect

    Omodei, Nicola; Battelino, Milan; Komin, Nukri; Longo, Francesco; McEnery, Julie; Norris, Jay; Ryde, Felix

    2007-05-01

    The Gamma-ray Large Area Space Telescope (GLAST), scheduled to be launched in fall of 2007, is the next generation satellite for high-energy gamma-ray astronomy. The Large Area Telescope (LAT) is a pair conversion telescope built with a high precision silicon tracker, a segmented CsI electromagnetic calorimeter and a plastic anticoincidence shield. The LAT will survey the sky in the energy range between 20 MeV to more than 300 GeV, shedding light on many issues left open by its highly successful predecessor EGRET. LAT will observe Gamma-Ray Bursts (GRB) in an energy range never explored before; to tie these frontier observations to the better-known properties at lower energies, a second instrument, the GLAST Burst Monitor (GBM) will provide important spectra and timing in the 10 keV to 30 MeV range. We briefly present the instruments onboard the GLAST satellite, their synergy in the GRB observations and the work done so far by the collaboration in simulation, analysis, and GRB sensitivity estimation.

  5. GRB Simulations in GLAST

    SciTech Connect

    Omodei, Nicola; Battelino, Milan; Komin, Nukri; Longo, Francesco; McEnery, Julie; Ryde, Felix; /Denver U.

    2007-10-22

    The Gamma-ray Large Area Space Telescope (GLAST), scheduled to be launched in fall of 2007, is the next generation satellite for high-energy gamma-ray astronomy. The Large Area Telescope (LAT) is a pair conversion telescope built with a high precision silicon tracker, a segmented CsI electromagnetic calorimeter and a plastic anticoincidence shield. The LAT will survey the sky in the energy range between 20 MeV to more than 300 GeV, shedding light on many issues left open by its highly successful predecessor EGRET. LAT will observe Gamma-Ray Bursts (GRB) in an energy range never explored before; to tie these frontier observations to the better-known properties at lower energies, a second instrument, the GLAST Burst Monitor (GBM) will provide important spectra and timing in the 10 keV to 30 MeV range. We briefly present the instruments onboard the GLAST satellite, their synergy in the GRB observations and the work done so far by the collaboration in simulation, analysis, and GRB sensitivity estimation.

  6. The Use of Weighting in Periodicity Searches in All-Sky Monitor Data: Applications to the GLAST LAT

    SciTech Connect

    Corbet, Robin; Dubois, Richard; /SLAC

    2009-06-25

    The light curves produced by all-sky monitors, such as the Rossi X-ray Timing Explorer All-Sky Monitor and the Swift Burst Alert Telescope (BAT), generally have non-uniform error bars. In searching for periodic modulation in this type of data using power spectra it can be important to use appropriate weighting of data points to achieve the best sensitivity. It was recently demonstrated that for Swift BAT data a simple weighting scheme can actually sometimes reduce the sensitivity of the power spectrum depending on source brightness. Instead, a modified weighting scheme, based on the Cochran semi-weighted mean, gives improved results independent of source brightness. We investigate the benefits of weighting power spectra in period searches using simulated GLAST LAT observations of {gamma}-ray binaries.

  7. Searching for Dark Matter Signatures in the GLAST LAT Electron Flux

    NASA Technical Reports Server (NTRS)

    Moiseev, Alexander; Profumo, Stefano

    2008-01-01

    We explored several viable scenarios of how LAT might observe DM, when the spectral feature is predicted to be observed in the HE electron flux It has been demonstrated elsewhere that LAT will be capable to detect HE electrons flux in energy range from 20 GeV to - 1 TeV with 520% energy resolution and good statistics If there is a DM-caused feature in the HE electron flux (in the range 20 GeV - 1 TeV), LAT will be the best current instrument to observe it!

  8. The Diffuse Galactic Gamma-Ray Emission Model for GLAST LAT

    SciTech Connect

    Porter, T.A.; Digel, S.W.; Grenier, I.A.; Moskalenko, I.V.; Strong, A.W.; /Garching, Max Planck Inst., MPE

    2007-06-13

    Diffuse emission from the Milky Way dominates the gamma-ray sky. About 80% of the high-energy luminosity of the Milky Way comes from processes in the interstellar medium. The Galactic diffuse emission traces interactions of energetic particles, primarily protons and electrons, with the interstellar gas and radiation field, thus delivering information about cosmic-ray spectra and interstellar mass in distant locations. Additionally, the Galactic diffuse emission is the celestial foreground for the study of gamma-ray point sources and the extragalactic diffuse gamma-ray emission. We will report on the latest developments in the modeling of the Galactic diffuse emission, which will be used for the Gamma Ray Large Area Space Telescope (GLAST) investigations.

  9. Gamma-Ray Large Area Space Telescope- GLAST Mission Overview

    NASA Technical Reports Server (NTRS)

    Moiseev, Alexander A.

    2007-01-01

    This viewgraph presentation reviews the Gamma-ray Large Area Space Telescope (GLAST), and the instrumentation that will be on the spacecraft: Large Area Telescope (LAT) and GLAST Burst Monitor (GBM). The presentation revierws in detail the LAT instrument.

  10. A Comprehensive Approach to Gamma-Ray Source Identification in the GLAST-LAT Era

    SciTech Connect

    Caraveo, Patrizia A.; Reimer, Olaf; /Stanford U., HEPL /KIPAC, Menlo Park

    2007-11-13

    Unveiling the nature of a vast number of unidentified sources is the most compelling problem facing today's high-energy (MeV-to-GeV) gamma-ray astronomy. However, unidentified sources are not peculiar to high-energy gamma-ray astronomy, they have been an ever-present phenomenon in astronomy. Indeed, every time a new astronomical window was opened, astronomers found sources they were not able to identify, i.e. to associate with previously known objects. This can happen either because such sources belong to a genuinely new (thus unknown) class or because their positions are not known accurately enough to allow for an unambiguous association between the newly found emitter and a known object. Thus, the lack of identification is frequently ascribed to poor angular resolution. Being unidentified, however, is a 'temporary' status: sooner or later better tools will allow the source identification, i.e. either its classification within a given class of astronomical objects or its recognition as belonging to a new class. Owing to the intrinsic limitations of gamma-ray detection technique, however, the instruments' angular resolution has not yet reached the minimum level required to permit the transition from the unidentified limbo to the paradise of known objects, thus creating a continuing unidentified high-energy gamma-ray source problem. Different approaches towards source identification have been pursued in the past. Here we will review the state of the art as well as the strategies devised for the GLAST era.

  11. The GLAST Burst Monitor

    SciTech Connect

    Meegan, Charles; Fishman, Gerald; Kouveliotou, Chryssa; Wilson-Hodge, Colleen; Bhat, Narayana; Connaughton, Valerie; Briggs, Michael; Paciesas, William; Preece, Robert; Diehl, Roland; Greiner, Jochen; Kienlin, Andreas von; Lichti, Giselher; Steinle, Helmut; Kippen, R. Marc

    2007-07-12

    The GLAST Burst Monitor (GBM) comprises an array of NaI and BGO scintillation detectors designed to enhance the scientific return from GLAST in the study of gamma-ray bursts (GRBs). By observing in the 10 keV to 30 MeV energy range, GBM extends the spectral coverage of GRBs more than 3 decades below the LAT energy threshold. GBM computes burst locations on-board, allowing repointing of the GLAST Observatory to place strong bursts within the LAT field-of-view to observe delayed high-energy emission.

  12. The GLAST Burst Monitor

    NASA Technical Reports Server (NTRS)

    Meegan, Charles; Bhat, Narayana; Connaughton, Valerie; Briggs, Michael; Diehl, Roland; Fishman, Gerald; Greiner, Jochen; Kippen, R. Marc; vonKienlin, Andreas; Kouveliotou, Chryssa; Lichti, Giselher; Paciesas, William; Preece, Robert; Steinle, Helmut; Wilson-Hodge, Colleen

    2007-01-01

    The GLAST Burst Monitor (GBM) comprises an array of NaI and BGO scintillation detectors designed to enhance the scientific return from GLAST in the study of gamma-ray bursts (GRBs). By observing in the 10 keV to 30 MeV energy range, GBM extends the spectral coverage of GRBs more than 3 decades below the LAT energy threshold. GBM computes burst locations on-board, allowing repointing of the GLAST Observatory to place strong bursts within the LAT field-of-view to observe delayed high-energy emission.

  13. GLAST's GBM Burst Trigger

    NASA Technical Reports Server (NTRS)

    Band, D.; Briggs, M.; Connaughton, V.; Kippen, M.; Preece, R.

    2003-01-01

    The GLAST Burst Monitor (GBM) will detect and localize bursts for the GLAST mission, and provide the spectral and temporal context in the traditional 10 keV to 25 MeV band for the high energy observations by the Large Area Telescope (LAT). The GBM will use traditional rate triggers in up to three energy bands, and on a variety of timescales between 16 ms and 16 s.

  14. GLAST's GBM Burst Trigger

    SciTech Connect

    Band, D.; Kippen, M.

    2004-09-28

    The GLAST Burst Monitor (GBM) will detect and localize bursts for the GLAST mission, and provide the spectral and temporal context in the traditional 10 keV to 25 MeV band for the high energy observations by the Large Area Telescope (LAT). The GBM will use traditional rate triggers in up to three energy bands, and on a variety of timescales between 16 ms and 16 s.

  15. GLAST GRB Observations and Capabilities

    NASA Technical Reports Server (NTRS)

    Meegan, Charles

    2008-01-01

    Gamma Ray Large Area Space Telescope (GLAST) is schedule to launch on May 16, 2008. GLAST consists of the Large Area Telescope (LAT), which will detect gamma rays above 20 MeV with unprecedented sensitivity, and the GLAST Burst Monitor (GBM), which will provide all-sky monitoring of GRBS in the 10 kev to 30 MeV range. Predicted GRB capabilities of GLAST will be described. The on-orbit performance of the instruments and preliminary GRB observations will be presented.

  16. The GLAST Background Model

    SciTech Connect

    Ormes, J.F.; Atwood, W.; Burnett, T.; Grove, E.; Longo, F.; McEnery, J.; Mizuno, T.; Ritz, S.; /NASA, Goddard

    2007-10-17

    In order to estimate the ability of the GLAST/LAT to reject unwanted background of charged particles, optimize the on-board processing, size the required telemetry and optimize the GLAST orbit, we developed a detailed model of the background particles that would affect the LAT. In addition to the well-known components of the cosmic radiation, we included splash and reentrant components of protons, electrons (e+ and e-) from 10 MeV and beyond as well as the albedo gamma rays produced by cosmic ray interactions with the atmosphere. We made estimates of the irreducible background components produced by positrons and hadrons interacting in the multilayered micrometeorite shield and spacecraft surrounding the LAT and note that because the orbital debris has increased, the shielding required and hence the background are larger than were present in EGRET. Improvements to the model are currently being made to include the east-west effect.

  17. The GLAST Background Model

    SciTech Connect

    Ormes, J. F.; Atwood, W.; Burnett, T.; Grove, E.; Longo, F.; McEnery, J.; Ritz, S.; Mizuno, T.

    2007-07-12

    In order to estimate the ability of the GLAST/LAT to reject unwanted background of charged particles, optimize the on-board processing, size the required telemetry and optimize the GLAST orbit, we developed a detailed model of the background particles that would affect the LAT. In addition to the well-known components of the cosmic radiation, we included splash and reentrant components of protons, electrons (e+ and e-) from 10 MeV and beyond as well as the albedo gamma rays produced by cosmic ray interactions with the atmosphere. We made estimates of the irreducible background components produced by positrons and hadrons interacting in the multilayered micrometeorite shield and spacecraft surrounding the LAT and note that because the orbital debris has increased, the shielding required and hence the background are larger than were present in EGRET. Improvements to the model are currently being made to include the east-west effect.

  18. Design and Characteristics of the Anticoincidence Detector for the GLAST Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Moiseev, A. A.; Hartman, R. C.; Johnson, T. E.; Ormes, J. F.; Thompson, D. J.

    2005-01-01

    The Anti-Coincidence Detector (ACD) is the outermost detector layer in the GLAST Large Area Telescope (LAT), surrounding the top and sides of the tracker. The purpose of the ACD is to detect and veto incident cosmic ray charged particles, which outnumber cosmic gamma rays by 3-4 orders of magnitude. The challenge in ACD design is that it must have high (0.9997) detection efficiency for singly charged relativistic particles, but must also have low sensitivity to backsplash particles. These are products of high- energy interactions in the LAT calorimeter. They can cause a veto signal in the ACD, resulting in loss of good gamma-ray events.

  19. The GLAST Burst Monitor

    SciTech Connect

    Bhat, P.N.; Briggs, M.S.; Connaughton, V.; Paciesas, W.S.; Preece, R.D.; Meegan, C.A.; Fishman, G.J.; Wilson, R.B.; Lichti, G.G.; Diehl, R.; Greiner, J.; Schoenfelder, V.; Kienlin, A. von; Kippen, R.M.; Kouveliotou, C.

    2004-09-28

    The Gamma Ray Large Area Space Telescope (GLAST) mission is a followup to the successful EGRET experiment onboard the Compton Gamma Ray Observatory (CGRO). It will provide a high-sensitivity survey of the sky in high-energy {gamma}-rays, and will perform detailed observations of persistent and transient sources. There are two experiments onboard the GLAST - the Large Area Telescope (LAT) and the GLAST Burst Monitor (GBM).The primary mission of the GBM instrument is to support the LAT in observing {gamma}-ray bursts (GRBs) by providing low-energy measurements with high time resolution and rapid burst locations over a large field-of-view ({>=} 8 sr). The GBM will complement the LAT measurements by observing GRBs in the energy range 10 keV to 30 MeV, the region of the spectral turnover in most GRBs. An important objective of the GBM is to compute the locations of GRB sources on-board the spacecraft and quickly communicate them to the LAT and to the ground to allow rapid followup observations. This information may be used to re-point the LAT towards particularly interesting burst sources that occurred outside its field-of-view. The GBM consists of 14 uncollimated scintillation detectors coupled to phototubes to measure {gamma}-ray energies and time profiles. Two types of detectors are used to obtain spectral information over a wide energy range: 12 NaI(Tl) detectors (10 keV to 1 MeV), and 2 BGO detectors (150 keV to 30 MeV). The detectors are distributed around the GLAST spacecraft to provide a large, unobstructed field of view. The 12 NaI(Tl) detectors are mounted with different orientations for use in locating GRB sources.

  20. Gamma-Ray Pulsar Studies with GLAST

    NASA Technical Reports Server (NTRS)

    Thompson, David J.

    2007-01-01

    This viewgraph presentation reviews the prospects of extending the understanding of gamma ray pulsars, and answering the open questions left from the limited observations that are available from current observatories. There are 2 new gamma ray observatories that are either on orbit or will be shortly launched: (1) Astro-rivelatore Gamma a Immagini LEggero (AGILE), and Gamma-ray Large Area Space Telescope (GLAST). On board GLAST there will be two instruments Large Area Telescope (LAT), and GLAST Burst Monitor (GBM).

  1. GLAST: Physics Goals And Instrument Status

    SciTech Connect

    Carson, Jennifer E.; /SLAC

    2006-11-07

    The Gamma-ray Large Area Space Telescope (GLAST) is a space-based observatory scheduled to launch in October 2007 with two instruments: (1) the GLAST Burst Monitor (GBM), sensitive to photon energies between 8 keV and 25 MeV and optimized to detect gamma-ray bursts, and (2) the Large Area Telescope (LAT), sensitive to gamma rays between 20 MeV and 300 GeV and designed to survey the gamma-ray sky with unprecedented sensitivity. We describe the LAT and the GBM. We then focus on the LAT's capabilities for studying active galactic nuclei.

  2. The GLAST Burst Monitor

    NASA Technical Reports Server (NTRS)

    Meegan, Charles A.

    2004-01-01

    The Gamma Ray Large Area Space Telescope (GLAST) observatory, scheduled for launch in 2007, comprises the Large Area Telescope (LAT) and the GLAST Burst Monitor (GBM). spectral changes that are known to occur within GRBs. between the NASA Marshall Space Flight Center, the University of Alabama in Huntsville, and the Max Planck Institute for Extraterrestrial Physics. It consists of an array of NaI and BGO scintillation detectors operating in the 10 kev to 25 MeV range. The field of view includes the entire unocculted sky when the observatory is pointing close to the zenith. The GBM will enhance LAT observations of GRBs by extending the spectral coverage into the range of current GRB databases, and will provide a trigger for reorienting the spacecraft to observe delayed emission from bursts outside the LAT field of view. GBM is expected to trigger on about 200 bursts per year, and will provide on-board locations of strong bursts accurate to better than 10 degrees.

  3. The GLAST Large Area Telescope Detector Performance Monitoring

    SciTech Connect

    Borgland, A.W.; Charles, E.; /SLAC

    2007-10-16

    The Large Area Telescope (LAT) is one of two instruments on board the Gamma-ray Large Area Telescope (GLAST), the next generation high energy gamma-ray space telescope. The LAT contains sixteen identical towers in a four-by-four grid. Each tower contains a silicon-strip tracker and a CsI calorimeter that together will give the incident direction and energy of the pair-converting photon in the energy range 20 MeV - 300 GeV. In addition, the instrument is covered by a finely segmented Anti-Coincidence Detector (ACD) to reject charged particle background. Altogether, the LAT contains more than 864k channels in the trackers, 1536 CsI crystals and 97 ACD plastic scintillator tiles and ribbons. Here we detail some of the strategies and methods for how we are planning to monitor the instrument performance on orbit. It builds on the extensive experience gained from Integration & Test and Commissioning of the instrument on ground.

  4. GLAST large area telescope - daily survey of high energy sky

    NASA Astrophysics Data System (ADS)

    Kamae, Tuneyoshi

    2003-07-01

    GLAST Large Area Telescope was proposed to NASA in 1999 as a follow-up of EGRET on-board Compton Gamma-Ray Observatory by an international collaboration. The proposal has been approved as a part of the GLAST observatory mission in its capability to explore a wide range of astrophysics with 5-40 times higher sensitivity and extended energy coverage (20MeV to 300GeV) than EGRET. The instrument consists of 16 towers of e+e- pair tracker, 16 blocks of segmented electro-magnetic calorimeter, and a set of anti-coicidence plastic scintillator tiles covering the tracker towers. It will have 5-10 times larger on-axis effective area, 6 times wider field-of-view (FOV), and up to 5 times better angular resolution when compared with EGRET. The Large Area Telescope will cover about 40% of the sky above the Earth's horizon in its FOV at any given time and will scan nearly the entire Universe every orbit (~ 90min): about 20% of Gamma-Ray Bursts will be observed from the onset of the bursts to the initial after-glow phase; all longer-lasting transients and variabilities will be detected daily at the improved sensitivity. The instrument has been prototyped twice between 1995 and 2001, designed almost to the Flight Model by the international collaboration of the US (NASA and DoE), France, Italy, Japan, and Sweden. The first prototype consisted of one tower of e+e- pair trackers, one block of segmented calorimeters and a smaller set of anti-coicidence plastic scintillator tiles (Beam Test Engineering Model, BTEM), which was put into e+, p, and γ beams at SLAC in the winter of 1999-2000. It was subsequently modified for a balloon experiment (Balloon Flight Engineering Model, BFEM) and flown at Palestine, Texas in August 2001. Data collected in the test experiments have been analyzed and compared with predictions of computer simulation codes such as Geant4. These studies have confirmed validity of the basic design, brought up a few issues for further improvement, and gathered data on

  5. Dark Matter Searches With GLAST

    SciTech Connect

    Wai, Lawrence; Nuss, E.

    2007-02-05

    Indirect detection of particle dark matter relies upon pair annihilation of Weakly Interaction Massive Particles (WIMPs), which is complementary to the well known techniques of direct detection (WIMP-nucleus scattering) and collider production (WIMP pair production). Pair annihilation of WIMPs results in the production of gamma-rays, neutrinos, and anti-matter. Of the various experiments sensitive to indirect detection of dark matter, the Gamma-ray Large Area Space Telescope (GLAST) may play the most crucial role in the next few years. After launch in late 2007, The GLAST Large Area Telescope (LAT) will survey the gamma-ray sky in the energy range of 20MeV-300GeV. By eliminating charged particle background above 100 MeV, GLAST may be sensitive to as yet to be observed Milky Way dark matter subhalos, as well as WIMP pair annihilation spectral lines from the Milky Way halo. Discovery of gamma-ray signals from dark matter in the Milky Way would not only demonstrate the particle nature of dark matter; it would also open a new observational window on galactic dark matter substructure. Location of new dark matter sources by GLAST would dramatically alter the experimental landscape; ground based gamma ray telescopes could follow up on the new GLAST sources with precision measurements of the WIMP pair annihilation spectrum.

  6. Gamma-Ray Burst Physics with GLAST

    SciTech Connect

    Omodei, N.; /INFN, Pisa

    2006-10-06

    The Gamma-ray Large Area Space Telescope (GLAST) is an international space mission that will study the cosmos in the energy range 10 keV-300 GeV, the upper end of which is one of the last poorly observed region of the celestial electromagnetic spectrum. The ancestor of the GLAST/LAT was the Energetic Gamma Ray Experiment Telescope (EGRET) detector, which flew onboard the Compton Gamma Ray Observatory (CGRO). The amount of information and the step forward that the high energy astrophysics made thanks to its 9 years of observations are impressive. Nevertheless, EGRET uncovered the tip of the iceberg, raising many questions, and it is in the light of EGRET's results that the great potential of the next generation gamma-ray telescope can be appreciated. GLAST will have an imaging gamma-ray telescope, the Large Area Telescope (LAT) vastly more capable than instruments own previously, as well as a secondary instrument, the GLAST Bursts Monitor, or GBM, to augment the study of gamma-ray bursts. Gamma-Ray Bursts (GRBs) science is one of the most exciting challenges for the GLAST mission, exploring the high energy emission of one of the most intense phenomena in the sky, shading light on various problems: from the acceleration of particles to the emission processes, to more exotic physics like Quantum Gravity effect. In this paper we report the work done so far in the simulation development as well as the study of the LAT sensitivity to GRB.

  7. GLAST Burst Monitor Trigger Classification Algorithm

    NASA Technical Reports Server (NTRS)

    Perrin, D. J.; Sidman, E. D.; Meegan, C. A.; Briggs, M. S.; Connaughton, V.

    2004-01-01

    The Gamma Ray Large Area Space Telescope (GLAST), currently set for launch in the first quarter of 2007, will consist of two instruments, the GLAST Burst Monitor (GBM) and the Large Area Telescope (LAT). One of the goals of the GBM is to identify and locate gamma-ray bursts using on-board software. The GLAST observatory can then be re-oriented to allow observations by the LAT. A Bayesian analysis will be used to distinguish gamma-ray bursts from other triggering events, such as solar flares, magnetospheric particle precipitation, soft gamma repeaters (SGRs), and Cygnus X-1 flaring. The trigger parameters used in the analysis are the burst celestial coordinates, angle from the Earth's horizon, spectral hardness, and the spacecraft geomagnetic latitude. The algorithm will be described and the results of testing will be presented.

  8. Galactic Variable Sky with EGRET and GLAST

    SciTech Connect

    Digel, S.W.; /SLAC

    2006-11-28

    The characteristics of the largely-unidentified Galactic sources of gamma rays that were detected by EGRET are reviewed. Proposed source populations that may have the correct spatial, spectral, luminosity, and variability properties to be the origins of the EGRET sources are also presented. Finally, the prospects for studying Galactic gamma-ray sources with the GLAST LAT are reviewed.

  9. GLAST Large Area Telescope Multiwavelength Opportunities

    NASA Technical Reports Server (NTRS)

    Thompson, David

    2008-01-01

    The Gamma-ray Large Area Space Telescope (GLAST) is scheduled for launch this year. Because the GLAST Large Area Telescope (LAT) has a huge field of view and the GLAST Observatory will be operated in scanning mode, it will survey the entire sky daily. The GLAST Mission and the LAT Collaboration invite cooperative efforts from theorists and observers at all wavelengths to help optimize the science. Possible topics include: (1) Blazars: These Active Galactic Nuclei are expected to be a major source class for LAT. Identifying new blazars, monitoring their variability, and joining programs to carry out planned or Target of Opportunity multiwavelength campaigns will all be important activities. The study of AGN gamma-ray jets can help link the accretion processes close to the black hole with the large-scale interaction of the AGN with its environment. (2) Unidentified Gamma-ray Sources: Modeling of possible gamma-ray sources is important to establish testable hypotheses. New gamma-ray sources need first to be identified with known objects by position, spectrum, or time variability, and then multiwavelength studies can be used to explore the astrophysical implications of high-energy radiation from these sources. The LAT team is committed to releasing a preliminary source list about six months after the start of science operations.

  10. Gamma-Ray Pulsar Studies with GLAST

    NASA Astrophysics Data System (ADS)

    Thompson, D. J.

    2008-02-01

    Some pulsars have their maximum observable energy output in the gamma-ray band, offering the possibility of using these high-energy photons as probes of the particle acceleration and interaction processes in pulsar magnetospheres. After an extended hiatus between satellite missions, the recently-launched AGILE mission and the upcoming Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) will allow gamma-ray tests of the theoretical models developed based on past discoveries. With its greatly improved sensitivity, better angular resolution, and larger energy reach than older instruments, GLAST LAT should detect dozens to hundreds of new gamma-ray pulsars and measure luminosities, light curves, and phase-resolved spectra with unprecedented resolution. It will also have the potential to find radio-quiet pulsars like Geminga, using blind search techniques. Cooperation with radio and X-ray pulsar astronomers is an important aspect of the LAT team's planning for pulsar studies.

  11. Gamma-Ray Pulsar Studies With GLAST

    SciTech Connect

    Thompson, D.J.; /NASA, Goddard

    2011-11-23

    Some pulsars have their maximum observable energy output in the gamma-ray band, offering the possibility of using these high-energy photons as probes of the particle acceleration and interaction processes in pulsar magnetospheres. After an extended hiatus between satellite missions, the recently-launched AGILE mission and the upcoming Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) will allow gamma-ray tests of the theoretical models developed based on past discoveries. With its greatly improved sensitivity, better angular resolution, and larger energy reach than older instruments, GLAST LAT should detect dozens to hundreds of new gamma-ray pulsars and measure luminosities, light curves, and phase-resolved spectra with unprecedented resolution. It will also have the potential to find radio-quiet pulsars like Geminga, using blind search techniques. Cooperation with radio and X-ray pulsar astronomers is an important aspect of the LAT team's planning for pulsar studies.

  12. Gamma-Ray Pulsar Studies with GLAST

    SciTech Connect

    Thompson, D. J.

    2008-02-27

    Some pulsars have their maximum observable energy output in the gamma-ray band, offering the possibility of using these high-energy photons as probes of the particle acceleration and interaction processes in pulsar magnetospheres. After an extended hiatus between satellite missions, the recently-launched AGILE mission and the upcoming Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) will allow gamma-ray tests of the theoretical models developed based on past discoveries. With its greatly improved sensitivity, better angular resolution, and larger energy reach than older instruments, GLAST LAT should detect dozens to hundreds of new gamma-ray pulsars and measure luminosities, light curves, and phase-resolved spectra with unprecedented resolution. It will also have the potential to find radio-quiet pulsars like Geminga, using blind search techniques. Cooperation with radio and X-ray pulsar astronomers is an important aspect of the LAT team's planning for pulsar studies.

  13. Serving Data to the GLAST Users Community

    SciTech Connect

    Stephens, Thomas E.

    2007-07-12

    The scientific community will access the public GLAST data through the website of the GLAST Science Support Center (GSSC). For most data products the GSSC website will link to the NASA High Energy Astrophysics Science Archive Research Center's (HEASARC) Browse interface, which will actually serve the data. For example, data from the GLAST Burst Monitor (GBM) from a given burst will be packaged together and accessible through Browse. However, the photon and event data produced by the Large Area Telescope (LAT), GLAST's primary instrument, will be distributed through a custom GSSC interface. These data will be collected over the LAT's large field-of-view, usually while the LAT is scanning the sky, and thus photons from a particular direction cannot be attributed to a single 'observation' in the traditional sense. Users will request all photons detected from a region on the sky over a specified time and energy range. Through its website the GSSC will also provide long and short term science timelines, spacecraft position and attitude histories, exposure maps and other scientific data products. The different data products provided by the GSSC will be described.

  14. Gamma Ray Large Area Space Telescope (GLAST) Balloon Flight Engineering Model: Overview

    NASA Technical Reports Server (NTRS)

    Thompson, D. J.; Godfrey, G.; Williams, S. M.; Grove, J. E.; Mizuno, T.; Sadrozinski, H. F.-W.; Kamae, T.; Ampe, J.; Briber, Stuart; Dann, James; White, Nicholas E. (Technical Monitor)

    2001-01-01

    The Gamma Ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) is a pair-production high-energy (greater than 20 MeV) gamma-ray telescope being built by an international partnership of astrophysicists and particle physicists for a satellite launch in 2006, designed to study a wide variety of high-energy astrophysical phenomena. As part of the development effort, the collaboration has built a Balloon Flight Engineering Model (BFEM) for flight on a high-altitude scientific balloon. The BFEM is approximately the size of one of the 16 GLAST-LAT towers and contains all the components of the full instrument: plastic scintillator anticoincidence system (ACD), high-Z foil/Si strip pair-conversion tracker (TKR), CsI hodoscopic calorimeter (CAL), triggering and data acquisition electronics (DAQ), commanding system, power distribution, telemetry, real-time data display, and ground data processing system. The principal goal of the balloon flight was to demonstrate the performance of this instrument configuration under conditions similar to those expected in orbit. Results from a balloon flight from Palestine, Texas, on August 4, 2001, show that the BFEM successfully obtained gamma-ray data in this high-background environment.

  15. GLAST Status and Application to Microquasars

    SciTech Connect

    Dubois, Richard; /SLAC

    2006-11-15

    The Gamma-ray Large Area Space Telescope (GLAST) is a next generation high energy gamma-ray observatory due for launch in Fall 2007. The primary instrument is the Large Area Telescope (LAT), which will measure gamma-ray flux and spectra from 20 MeV to > 300 GeV and is a successor to the highly successful EGRET experiment on CGRO. The LAT will have better angular resolution, greater effective area, wider field of view and broader energy coverage than any previous experiment in this energy range. An overview of the LAT instrument design and construction is presented which includes performance estimates with particular emphasis on how these apply to studies of microquasars. The nature and quality of the data that will be provided by the LAT is described with results from recent detailed simulations that illustrate the potential of the LAT to observe gamma ray variability and spectra.

  16. Observing Gamma-ray Bursts with GLAST

    NASA Technical Reports Server (NTRS)

    McEnery, Julie

    2008-01-01

    The Gamma-ray Large Area Telescope (GLAST) is a satellite-based observatory to study the high-energy gamma-ray sky. The Large Area Telescope, the main instrument, is a pair-conversion telescope which will survey the sky in the energy range 20 MeV to greater than 300 GeV. The LAT's wide field of view (greater than 2 sr), large effective area and low deadtime combine to provide excellent high-energy gamma-ray observations of GRB. To tie these frontier high-energy observations to the better-known properties at lower energies, a second instrument, the GLAST Burst Monitor (GBM) will provide important spectra and timing in the 8 keV to 30 MeV range. Upon detection of a GRB by the LAT or the GBM, the spacecraft can autonomously repoint to keep the GRB location within the LAT field of view, allowing high-energy afterglow observations. We describe how the instruments, spacecraft, and ground system work together to provide observations of gamma-ray bursts from 8 keV to over 300 GeV and provide rapid notification of these observations to the wider gamma-ray burst community. Analysis and simulation tools dedicated to the GRB science have been developed. In this contribution we show the expected LAT sensitivity obtained with such simulations, and illustrate the results we expect from GLAST observations with spectral and temporal analysis of simulated GRB.

  17. The GLAST Guest Investigator Program

    NASA Technical Reports Server (NTRS)

    Band, David L.

    2007-01-01

    We provide an overview of the GLAST Guest Investigator (GI) program, which will support basic research relevant to the GLAST mission in yearly cycles beginning approximately two months after launch. Current details about the GLAST GI program will always be posted on the GLAST Science Support Center (GSSC) website: http://glast.gsfc.nasa.gov/ssc/.

  18. GLAST: GeV astronomy in a multiwavelength context

    NASA Astrophysics Data System (ADS)

    Thompson, David J.

    2004-04-01

    The GLAST Large Area Telescope (LAT), successor to Energetic Gamma-ray Experiment Telescope (EGRET) on the Compton Observatory, will play an important role in multiwavelength studies during the second half of this decade. Operating at energies between 20 MeV and greater than 300 GeV with sensitivity 30 or more times greater than that of EGRET, the LAT will offer good spatial and time resolution over a large (>2 sr) field of view. The LAT will bring insight to the whole range of high-energy γ-ray phenomena, including bursts, active galactic nuclei, pulsars, supernova remnants, diffuse emission and unidentified sources. In essentially all cases, the maximum scientific return will come from coordinated (although not necessarily simultaneous) multiwavelength observations. Particularly with its planned scanning mode of operation, GLAST will have full sky coverage on relatively short time scales. The LAT team looks forward to cooperating with observers at other wavelengths.

  19. LAT and Solar Neutrons: Preliminary estimates

    SciTech Connect

    Longo, Francesco |

    2007-07-12

    GLAST LAT will detect several solar flares in gamma rays. Motivated by the CGRO results on neutrons emitted during a solar flare, we try to estimate the possibility of the LAT to detect solar neutrons. Besides gamma rays, neutrons could indeed interact in the LAT instrument and mimic a gamma-ray signal. An estimate of the contamination of gamma-ray detection in solar flares by the neutron component is given.

  20. Gamma Ray Burst Observations with Swift and GLAST

    NASA Technical Reports Server (NTRS)

    Gehrels, Neil

    2007-01-01

    The Swift and GLAST missions promise a great increase in our understanding of the gamma-ray universe. Swift was launched in November 2004 with a primary objective to study gamma-ray bursts. All instruments are performing well and more than 200 GRBs have been studied in detail. Major advances have already been made in the areas of short bursts, high redshift events and afterglow physics. The GLAST mission is scheduled for launch in fall 2007. It features a large newtechnology instrument for high energy gamma-ray observations. Hundreds of gamma-ray bursts will be detected by the LAT and GBM instruments. The talk will discuss the GRB science available with GLAST and the opportunities for joint Swift and GLAST observations of bursts.

  1. Expected Performance of the GLAST Burst Monitor

    NASA Technical Reports Server (NTRS)

    Meegan, Charles; Fishman, Gerald; Kouveliotou, Chryssa; Wilson-Hodge, Colleen; Paciesas, William; Preece, Robert; Briggs, Michael; Bhat, Narayana; Connaughton, Valerie; Greiner, Jochen; vonKienlin, Andreas; Diehl, Roland; Steinle, Helmut; Bissaldi, Elisabetta; Kippen, R. Marc

    2007-01-01

    The GLAST Burst Monitor (GBM) will enhance LAT observations of GRBs by extending the spectral coverage from the LAT threshold down to approx. 8 kev, and will provide a trigger for re-orienting the spacecraft to observe delayed emission from selected bursts outside the LAT field of view. GBM consists of twelve NaI scintillation detectors operating in the 8 kev to 1 MeV energy range and two BGO scintillation detectors operating in the 150 keV to 30 MeV energy range. Detector resolution, effective area, and angular response have been determined by calibrations. Analyses indicate that the on-board burst threshold will be approx. 0.7 photon/cm2/s and the on-board burst localization accuracy will typically be better than 8 degrees.

  2. Expected Performance of the GLAST Burst Monitor

    SciTech Connect

    Meegan, Charles; Fishman, Gerald; Kouveliotou, Chryssa; Wilson-Hodge, Colleen; Bissaldi, Elisabetta; Diehl, Roland; Greiner, Jochen; Kienlin, Andreas von; Lichti, Giselher; Steinle, Helmut; Kippen, R. Marc

    2008-05-22

    The GLAST Burst Monitor (GBM) will enhance LAT observations of GRBs by extending the spectral coverage from the LAT threshold down to {approx}8 keV, and will provide a trigger for re-orienting the spacecraft to observe delayed emission from selected bursts outside the LAT field of view. GBM consists of twelve NaI scintillation detectors operating in the 8 keV to 1 MeV energy range and two BGO scintillation detectors operating in the 150 keV to 30 MeV energy range. Detector resolution, effective area, and angular response have been determined by calibrations. Analyses indicate that the on-board burst threshold will be {approx}0.7 photons cm{sup -2}s{sup -1} and the on-board burst localization accuracy will typically be better than 8 deg.

  3. GLAST Large Area Telescope Multiwavelength Planning

    NASA Technical Reports Server (NTRS)

    Thompson, D. J.; Cameron, R. A.; Digel, S. W.; Wood, K. S.

    2006-01-01

    Because gamma-ray astrophysics depends in many ways on multiwavelength studies, the GLAST Large Area Telescope (LAT) Collaboration has started multiwavelength planning well before the scheduled 2007 launch of the observatory. Some of the high-priority needs include: (1) radio and X-ray timing of pulsars; (2) expansion of blazar catalogs, including redshift measurements (3) improved observations of molecular clouds, especially at high galactic latitudes; (4) simultaneous broad-spectrum blazar flare measurements; (5) characterization of gamma-ray transients, including gamma ray bursts; (6) radio, optical, X-ray and TeV counterpart searches for unidentified gamma-ray sources. Work on the first three of these activities is needed before launch. The GLAST Large Area Telescope is an international effort, with U.S. funding provided by the Department of Energy and NASA.

  4. Gev Gamma-ray Astronomy in the Era of GLAST

    NASA Technical Reports Server (NTRS)

    Gehrels, Neil; White, Nicholas E. (Technical Monitor)

    2000-01-01

    The Gamma Ray Large Area Space Telescope (GLAST) is a high energy astronomy mission planned for launch in 2005. GLAST features two instruments; the Large Area Telescope (LAT) operating from 20 MeV - 300 GeV and the Gamma-ray Burst Monitor (GBM) operating from 10 keV - 25 MeV. GLAST observations will contribute to our understanding of active galactic nuclei and their jets, gamma-ray bursts, extragalactic and galactic diffuse emissions, dark matter, supernova remnants, pulsars, and the unidentified high energy gamma-ray sources. The LAT sensitivity is 4 x 10(exp -9) photons per square centimeter per second (greater than 100 MeV) for a one year all-sky survey, which is a factor of greater than 20 better than CGRO/EGRET. GLAST spectral observations of gamma-ray bursts cover over 6 orders of magnitude in energy thanks to the context observations of the GBM. The upper end of the LAT energy range merges with the low energy end of ground-based observatories to provide a remarkable new perspective on particle acceleration in the Universe.

  5. Gamma-Ray Pulsar Candidates for GLAST

    NASA Technical Reports Server (NTRS)

    Thompson, D. J.

    2008-01-01

    The Gamma-ray Large Area Space Telescope (GLAST) will be launched this year, and its Large Area Telescope (LAT) is expected to discover scores to hundreds of gamma-ray pulsars. This poster discusses which of the over 1700 known pulsars, mostly visible only at radio frequencies, are likely to emit greater than 100 MeV gamma rays with intensities detectable by the LAT. The main figure of merit used to select gamma-ray pulsar candidates is sqrt(E-dot)/d2, where E-dot is the energy loss due to rotational spin-down, and d is the distance to the pulsar. The figure of merit incorporates spin-down flux at earth (proportional to E-dot/d2) times efficiency, assumed proportional to l/sqrt(E-dot). A few individual objects are cited to illustrate the issues. Since large E-dot pulsars also tend to have large timing noise and occasional glitches, their ephemerides can become inaccurate in weeks to months. To detect and study the gamma-ray emission the photons must be accurately tagged with the pulse phase. With hours to days between gamma-ray photon arrival times from a pulsar and months to years of LAT exposure needed for good detections, GLAST will rely on radio and X-ray timing measurements throughout the continuous gamma-ray observations. The poster will describe efforts to coordinate pulsar timing of the candidate gamma-ray pulsars.

  6. Gamma-Ray Pulsar Candidates for GLAST

    NASA Technical Reports Server (NTRS)

    Thompson, David J.; Smith, D. A.; Dumora, D.; Guillemot, L.; Parent, D.; Reposeur, T.; Grove, E.; Romani, R. W.; Thorsett, S. E.

    2007-01-01

    The Gamma-ray Large Area Space Telescope (GLAST) will be launched less than a year from now, and its Large Area Telescope (LAT) is expected to discover scores to hundreds of gamma-ray pulsars. This poster discusses which of the over 1700 known pulsars, mostly visible only at radio Erequencies, are likely to emit greater than l00 MeV gamma rays with intensities detectable by the LAT. The main figure of merit used to select gamma-ray pulsar candidates is sqrt(E-dot)/d^2, where E-dot is the energy loss due to rotational spindown, and d is the distance to the pulsar. The figure of merit incorporates spin-down flux at earth (proportional to E-dot/d^2) times efficiency, assumed proportional to 1/sqrt(E-dot). A few individual objects are cited to illustrate the issues. Since large E-dot pulsars also tend to have large timing noise and occasional glitches, their ephemerides can become inaccurate in weeks to months. To detect and study the gamma-ray emission the photons must be accurately tagged with the pulse phase. With hours to days between gamma-ray photon arrival times from a pulsar and months to years of LAT exposure needed for good detections, GLAST will need timing measurements throughout the continuous gamma-ray observations. The poster will describe efforts to coordinate pulsar timing of the candidate gamma-ray pulsars.

  7. Pulsar Astronomy with GLAST

    SciTech Connect

    Thorsett, Stephen

    2005-09-12

    Despite their name, the rotation powered neutron stars called "radio pulsars" are actually most luminous in the hard x-ray and gamma-ray bands. GLAST will be the first high-energy satellite with sufficient sensitivity to detect and study large numbers of these pulsars. I will review GLAST's key science goals in pulsar astrophysics and summarize the extraordinary advances in low-energy pulsar surveys since the days of CGRO.

  8. Simultaneous Radio to (Sub-) Mm-Monitoring of Variability and Spectral Shape Evolution of Potential GLAST Blazars

    SciTech Connect

    Fuhrmann, L.; Zensus, J.A.; Krichbaum, T.P.; Angelakis, E.; Readhead, A.C.S.; /Caltech

    2011-11-29

    The Large Area Telescope (LAT) instrument onboard GLAST offers a tremendous opportunity for future blazar studies. In order to fully benefit from its capabilities and to maximize the scientific return from the LAT, it is of great importance to conduct dedicated multi-frequency monitoring campaigns that will result comprehensive observations. Consequently, we initiated an effort to conduct a GLAST-dedicated, quasi-simultaneous, broad-band flux-density (and polarization) monitoring of potential GLAST blazars with the Effelsberg and OVRO radio telescopes (11 cm to 7mm wavelength). Here, we present a short overview of these activities which will complement the multi-wavelengths activities of the GLAST/LAT collaboration towards the 'low-energy' radio bands. Further we will give a brief outlook including the extension of this coordinated campaign towards higher frequencies and future scientific aims.

  9. Design and Initial Tests of the Tracker-Converter ofthe Gamma-ray Large Area Space Telescope

    SciTech Connect

    Atwood, W.B.; Bagagli, R.; Baldini, L.; Bellazzini, R.; Barbiellini, G.; Belli, F.; Borden, T.; Brez, A.; Brigida, M.; Caliandro, G.A.; Cecchi, C.; Cohen-Tanugi, J.; De Angelis, A.; Drell, P.; Favuzzi, C.; Fukazawa, Y.; Fusco, P.; Gargano, F.; Germani, S.; Giannitrapani, R.; Giglietto, N.; /UC, Santa Cruz /INFN, Pisa /Pisa U. /INFN, Trieste /INFN, Rome /Rome U.,Tor Vergata /SLAC /INFN, Bari /Bari U. /INFN, Perugia /Perugia U. /Udine U. /Hiroshima U. /NASA, Goddard /Maryland U. /Tokyo Inst. Tech. /INFN, Padua /Padua U. /Pisa, Scuola Normale Superiore

    2007-04-16

    The Tracker subsystem of the Large Area Telescope (LAT) science instrument of the Gamma-ray Large Area Space Telescope (GLAST) mission has been completed and tested. It is the central detector subsystem of the LAT and serves both to convert an incident gamma-ray into an electron-positron pair and to track the pair in order to measure the gamma-ray direction. It also provides the principal trigger for the LAT. The Tracker uses silicon strip detectors, read out by custom electronics, to detect charged particles. The detectors and electronics are packaged, along with tungsten converter foils, in 16 modular, high-precision carbon-composite structures. It is the largest silicon-strip detector system ever built for launch into space, and its aggressive design emphasizes very low power consumption, passive cooling, low noise, high efficiency, minimal dead area, and a structure that is highly transparent to charged particles. The test program has demonstrated that the system meets or surpasses all of its performance specifications as well as environmental requirements. It is now installed in the completed LAT, which is being prepared for launch in early 2008.

  10. Building ISOC Status Displays for the Large AreaTelescope aboard the Gamma Ray Large Area Space Telescope (GLAST) Observatory

    SciTech Connect

    Ketchum, Christina; /SLAC

    2006-09-01

    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.

  11. Prospects for Pulsar Studies with the GLAST Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.

    2007-01-01

    The Large Area Telescope (LAT) on the Gamma-ray Large Area Space Telescope (GLAST), due to launch in November 2007, will have unprecedented sensitivity and energy resolution for gamma-rays in the range of 30 MeV to 200 GeV. GLAST is therefore expected to provide major advances in the understanding of high-energy emission from rotation-powered pulsars. As the only presently known galactic GeV source class; pulsars will be one of the most important sources for study with GLAST. The main science goals of the LAT for pulsar studies include an increase in the number of detected radio-loud and radio-quiet gamma-ray pulsars, including millisecond pulsars, giving much better statistics for elucidating population characteristics, measurement of the high-energy spectrum and the shape of spectral cutoffs and determining pulse profiles for a variety of pulsars of different age. Further, measurement of phase-resolved spectra and energy dependent pulse profiles of the brighter pulsars should allow detailed tests of magnetospheric particle acceleration and radiation mechanisms, by comparing data with theoretical models that have been developed. Additionally, the LAT will have the sensitivity to allow blind pulsation searches of nearly all unidentified EGRET sources, to possibly uncover more radio-quiet Geminga-like pulsars.

  12. Prospects for Pulsar Studies with the GLAST Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.

    2007-01-01

    The Large Area Telescope (LAT) on the Gamma-ray Large Area Space Telescope (GLAST), due to launch in November 2007, will have unprecedented sensitivity and energy resolution for gamma-rays in the range of 30 MeV to 200 GeV. GLAST is therefore expected to provide major advances in the understanding of high-energy emission from rotation-powered p ulsars. As the only presently known galactic GeV source class, pulsar s will be one of the most important sources for study with GLAST. The main science goals of the LAT for pulsar studies include an increase in the number of detected radio-loud and radio-quiet gamma-ray pulsar s, including millisecond pulsars, giving much better statistics for e lucidating population characteristics, measurement of the high-energy spectrum and the shape of spectral cutoffs and determining pulse profiles for a variety of pulsars of different age. Further, measurement of phase-resolved spectra and energy dependent pulse profiles of the brighter pulsars should allow detailed tests of magnetospheric partic le acceleration and radiation mechanisms, by comparing data with theo retical models that have been developed. Additionally, the LAT will have the sensitivity to allow blind pulsation searches of nearly all un identified EGRET sources, to possibly uncover more radio-quiet Geming a-like pulsars.

  13. Prospects for Pulsar Studies with the GLAST Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.

    2006-01-01

    The Large Area Telescope (LAT) on the Gamma-ray Large Area Space Telescope (GLAST) will have unprecedented sensitivity and energy resolution for gamma-rays in the range of 30 MeV to 200 GeV. GLAST is therefore expected to provide major advances in the understanding of high-energy emission from rotation-powered pulsars. As the only presently known galactic GeV source class, pulsars will be one of the most important sources for study with GLAST. The main science goals of the LAT for pulsar studies include an increase in the number of detected radio-loud and radio-quiet gamma ray pulsars, including millisecond pulsars, giving much better statistics for elucidating population characteristics, measurement of the high-energy spectrum and the shape of spectral cutoffs and determining pulse profiles for a variety of pulsars of different age. Further, measurement of phase-resolved spectra and energy dependent pulse profiles of the brighter pulsars should allow detailed tests of magnetospheric particle acceleration and radiation mechanisms, by comparing data with theoretical models that have been developed. Additionally, the LAT will have the sensitivity to allow blind pulsation searches of nearly all unidentified EGRET sources, to possibly uncover more radio-quiet Geminga-like pulsars.

  14. Performance of the Anti-Coincidence Detector on the GLAST Large Area Telescope

    SciTech Connect

    Thompson, D.J.; Charles, E.; Hartman, R.C.; Moiseev, A.A.; Ormes, J.F.; /NASA, Goddard /Denver U.

    2007-10-22

    The Anti-Coincidence Detector (ACD), the outermost detector layer in the Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT), is designed to detect and veto incident cosmic ray charged particles, which outnumber cosmic gamma rays by 3-4 orders of magnitude. The challenge in ACD design is that it must have high (0.9997) detection efficiency for singly-charged relativistic particles, but must also have a low probability for self-veto of high-energy gammas by backsplash radiation from interactions in the LAT calorimeter. Simulations and tests demonstrate that the ACD meets its design requirements. The performance of the ACD has remained stable through stand-alone environmental testing, shipment across the U.S., installation onto the LAT, shipment back across the U.S., LAT environmental testing, and shipment to Arizona. As part of the fully-assembled GLAST observatory, the ACD is being readied for final testing before launch.

  15. New Results on High Energy Cosmic Ray Electrons Observed with Fermi LAT and Their Implications on the Models of Pulsars

    NASA Technical Reports Server (NTRS)

    Moiseev, Alexander

    2010-01-01

    This viewgraph presentation describes, in detail, the Fermi Large Area Telescope (LAT) and GLAST Burst Monitor (GBM). Observations made from the June 11, 2008 launch and a discussion of observations made of high energy cosmic ray electrons is also presented.

  16. Gamma-ray Large-Area Space Telescope (GLAST) balloon flight data handling overview

    NASA Astrophysics Data System (ADS)

    Burnett, T. H.; Chekhtman, A.; Do Couto E Silva, E.; Dubois, R.; Flath, D.; Gable, I.; Grove, J. E.; Hartman, R. C.; Kamae, T.; Kavelaars, A.; Kelly, H.; Kotani, T.; Kuss, M.; Lauben, D.; Lindner, T.; Lumb, N.; Mizuno, T.; Moiseev, A.; Ozaki, M.; Rochester, L. S.; Schaefer, R.; Spandre, G.; Thompson, D. J.; Usher, T.; Young, K.

    2002-08-01

    The GLAST Balloon Flight Engineering Model (BFEM) represents one of 16 towers that constitute the Large Area Telescope (LAT), a high-energy (>20 MeV) gamma-ray pair-production telescope being built by an international partnership of astrophysicists and particle physicists for a satellite launch in 2006. The prototype tower consists of a Pb/Si pair-conversion tracker (TKR), a CsI hodoscopic calorimeter (CAL), an anti-coincidence detector (ACD) and an autonomous data acquisition system (DAQ). The self-triggering capabilities and performance of the detector elements have been previously characterized using positron, photon and hadron beams. External target scintillators were placed above the instrument to act as sources of hadronic showers. This paper provides a comprehensive description of the BFEM data-reduction process, from receipt of the flight data from telemetry through event reconstruction and background rejection cuts. The goals of the ground analysis presented here are to verify the functioning of the instrument and to validate the reconstruction software and the background-rejection scheme.

  17. GLAST Solar System Science

    SciTech Connect

    Share, Gerald H.; Murphy, Ronald J.

    2007-07-12

    We briefly discuss GLAST's capabilities for observing high-energy radiation from various energetic phenomena in our solar system. These emissions include: bremsstrahlung, nuclear-line and pion-decay gamma-radiation, and neutrons from solar flares; bremsstrahlung and pion-decay gamma radiation from cosmic-ray interactions with the Sun, the Moon, and the Earth's atmosphere; and inverse Compton radiation from cosmic-ray electron interactions with sunlight.

  18. GLAST and Suzaku

    NASA Technical Reports Server (NTRS)

    Sambruna, Rita

    2007-01-01

    The upcoming years will see a formidable synergy of high-energy observatories for the study of extragalactic objects, especially AGN. In particular, the launch of GLAST will allow us coordinated monitoring of sources with Suzaku over a very large energy band, from medium X-rays to GeV energies. In this talk I will review the science issues that such a remarkable coverage will enable us to address.

  19. Calibration of the GLAST Burst Monitor detectors

    SciTech Connect

    Kienlin, Andreas von; Bissaldi, Elisabetta; Lichti, Giselher G.; Steinle, Helmut; Diehl, Roland; Greiner, Jochen; Krumrey, Michael; Gerlach, Martin; Fishman, Gerald J.; Meegan, Charles; Kouveliotou, Chryssa; Wilson-Hodge, Colleen; Bhat, Narayana; Briggs, Michael S.; Connaughton, Valerie; Paciesas, William; Preece, Robert; Kippen, R. Marc

    2007-07-12

    The GLAST Burst Monitor (GBM) will augment the capabilities of GLAST for the detection of cosmic gamma-ray bursts by extending the energy range (20 MeV to > 300 GeV) of the Large Area Telescope (LAT) towards lower energies by 2 BGO-detectors (150 keV to 30 MeV) and 12 NaI(Tl) detectors (10 keV to 1 MeV). The physical detector response of the GBM instrument for GRBs is determined with the help of Monte Carlo simulations, which are supported and verified by on-ground calibration measurements, performed extensively with the individual detectors at the MPE in 2005. All flight and spare detectors were irradiated with calibrated radioactive sources in the laboratory (from 14 keV to 4.43 MeV). The energy/channel-relations, the dependences of energy resolution and effective areas on the energy and the angular responses were measured. Due to the low number of emission lines of radioactive sources below 100 keV, calibration measurements in the energy range from 10 keV to 60 keV were performed with the X-ray radiometry working group of the Physikalisch-Technische Bundesanstalt (PTB) at the BESSY synchrotron radiation facility, Berlin.

  20. Calibration of the GLAST Burst Monitor Detectors

    SciTech Connect

    von Kienlin, Andreas; Bissaldi, Elisabetta; Lichti, Giselher G.; Steinle, Helmut; Krumrey, Michael; Gerlach, Martin; Fishman, Gerald J.; Meegan, Charles; Bhat, Narayana; Briggs, Michael S.; Diehl, Roland; Connaughton, Valerie; Greiner, Jochen; Kippen, R.Marc; Kouveliotou, Chryssa; Paciesas, William; Preece, Robert; Wilson-Hodge, Colleen

    2011-11-29

    The GLAST Burst Monitor (GBM) will augment the capabilities of GLAST for the detection of cosmic gamma-ray bursts by extending the energy range (20 MeV to > 300 GeV) of the Large Area Telescope (LAT) towards lower energies by 2 BGO-detectors (150 keV to 30 MeV) and 12 NaI(Tl) detectors (10 keV to 1 MeV). The physical detector response of the GBM instrument for GRBs is determined with the help of Monte Carlo simulations, which are supported and verified by on-ground calibration measurements, performed extensively with the individual detectors at the MPE in 2005. All flight and spare detectors were irradiated with calibrated radioactive sources in the laboratory (from 14 keV to 4.43 MeV). The energy/channel-relations, the dependences of energy resolution and effective areas on the energy and the angular responses were measured. Due to the low number of emission lines of radioactive sources below 100 keV, calibration measurements in the energy range from 10 keV to 60 keV were performed with the X-ray radiometry working group of the Physikalisch-Technische Bundesanstalt (PTB) at the BESSY synchrotron radiation facility, Berlin.

  1. GLAST Science Across Wavelengths

    NASA Astrophysics Data System (ADS)

    Blandford, R. D.

    2006-12-01

    The GLAST satellites is almost guaranteed to revolutionize GeV gamma ray astronomy because of the great discoveries that are being made at hard X-ray energy by the Suzaku and Swift satellites and in the TeV range using the H.E.S.S. and Magic telescopes. Unidentified EGRET sources are likely to be identified and new and fainter sources will be found. Known classes of sources blazars, pulsars, gamma ray bursts, supernova remnants, binary X-ray sources and so on will be monitored in much greater detail. Finally, there is the need to limit or even detect dark matter through its annihilation signature. The science that will emerge from GLAST will be determined in large measure by the effort that is put into multiwavelength observing. This will require significant commitments of observing time for monitoring pulsar arrival times, measuring faint galaxy spectra, detecting GeV gamma rays gamma ray bursts and so on. In this talk I will attempt to summarize current thinking on the GLAST multi-wavelength observing program and propose some new approaches.

  2. GLAST Large Area Telescope Multiwavelength Planning

    SciTech Connect

    Reimer, O.; Michelson, P.F.; Cameron, R.A.; Digel, S.W.; Thompson, D.J.; Wood, K.S.

    2007-01-03

    Gamma-ray astrophysics depends in many ways on multiwavelength studies. The Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) Collaboration has started multiwavelength planning well before the scheduled 2007 launch of the observatory. Some of the high-priority multiwavelength needs include: (1) availability of contemporaneous radio and X-ray timing of pulsars; (2) expansion of blazar catalogs, including redshift measurements; (3) improved observations of molecular clouds, especially at high galactic latitudes; (4) simultaneous broad-band blazar monitoring; (5) characterization of gamma-ray transients, including gamma ray bursts; (6) radio, optical, X-ray and TeV counterpart searches for reliable and effective sources identification and characterization. Several of these activities are needed to be in place before launch.

  3. GLAST Large Area Telescope Multiwavelength Planning

    NASA Technical Reports Server (NTRS)

    Reimer, O.; Michelson, P. F.; Cameron, R. A.; Digel, S. W.; Thompson, D. J.; Wood, K. S.

    2007-01-01

    Gamma-ray astrophysics depends in many ways on multiwavelength studies. The Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) Collaboration has started multiwavelength planning well before the scheduled 2007 launch of the observatory. Some of the high-priority multiwavelength needs include: (1) availability of contemporaneous radio and X-ray timing of pulsars; (2) expansion of blazar catalogs, including redshift measurements; (3) improved observations of molecular clouds, especially at high galactic latitudes; (4) simultaneous broad-spectrum blazar monitoring; (5) characterization of gamma-ray transients, including gamma ray bursts; (6) radio, optical, X-ray and TeV counterpart searches for reliable and effective sources identification and characterization. Several of these activities are needed to be in place before launch.

  4. The GLAST Silicon-Strip Tracking System

    SciTech Connect

    Johnson, R

    2004-09-30

    The GLAST instrument concept is a gamma-ray pair conversion telescope that uses silicon microstrip detector technology to track the electron-positron pairs resulting from gamma ray conversions in thin lead foils. A cesium iodide calorimeter following the tracker is used to measure the gamma-ray energy. Silicon strip technology is mature and robust, with an excellent heritage in space science and particle physics. It has many characteristics important for optimal performance of a pair conversion telescope, including high efficiency in thin detector planes, low noise, and excellent resolution and two-track separation. The large size of GLAST and high channel count in the tracker puts demands on the readout technology to operate at very low power, yet with sufficiently low noise occupancy to allow self triggering. A prototype system employing custom-designed ASIC's has been built and tested that meets the design goal of approximately 200 {micro}W per channel power consumption with a noise occupancy of less than one hit per trigger per 10,000 channels. Detailed design of the full-scale tracker is well advanced, with non-flight prototypes built for all components, and a complete 50,000 channel engineering demonstration tower module is currently under construction and will be tested in particle beams in late 1999. The flight-instrument conceptual design is for a 4 x 4 array of tower modules with an aperture of 2.9 m{sup 2} and an effective area of greater than 8000 cm{sup 2}.

  5. GLAST: Launched And Being Commissioned - Status And Prospects for Microquasars

    SciTech Connect

    Dubois, Richard; /SLAC

    2011-12-01

    GLAST: Launched And Being Commissioned - Status And Prospects for Microquasars The Fermi Gamma-ray Space Telescope (Fermi) is a next generation high energy gamma-ray observatory launched in June 2008. The primary instrument is the Large Area Telescope (LAT), which will measure gamma-ray flux and spectra from 20 MeV to > 300 GeV and is a successor to the highly successful EGRET experiment on CGRO. The LAT has better angular resolution, greater effective area, wider field of view and broader energy coverage than any previous experiment in this energy range. An overview of the LAT instrument design and construction is presented which includes performance estimates with particular emphasis on how these apply to studies of microquasars. Early results on LS I +61 303 detection are presented.

  6. Supporting the GLAST User Community

    NASA Technical Reports Server (NTRS)

    Band, David L.

    2004-01-01

    The Gamma-ray Large Area Space Telescope (GLAST) Science Support Center (GSSC) is the scientific community's interface with GLAST. The GSSC will provide data, analysis software and documentation. In addition, the GSSC will administer the guest investigator program for NASA HQ. Consequently, the GSSC will provide proposal preparation tools to assist proposers in assessing the feasibility of observing sources of interest.

  7. Source identification with GLAST

    SciTech Connect

    Lonjou, Vincent; Knoedlseder, Juergen

    2007-07-12

    With more than 50% of unidentified sources, the third EGRET catalogue reflects the complexity of source identification in the GeV domain. In that context, we developed a dedicated GLAST ScienceTool dubbed gtsrcid for the general purpose of source identification. gtsrcid has been designed in a very flexible way and allows cross correlation with any counterpart catalogue using user-definable figures-of-merit. Our source identification strategy, the results for DC2 as well as possible improvements of our identification procedures are presented.

  8. GLAST and Suzaku: Study on Cosmic-Ray Acceleration And Interaction in the Cosmos

    SciTech Connect

    Kamae, T.; /KIPAC, Menlo Park /SLAC

    2008-05-23

    The Gamma-Ray Large Area Space Telescope (GLAST) is an international and multiagency mission scheduled for launch in the fall 2007. The Large Area Telescope (LAT), the primary instrument of the mission, will survey the high energy sky found to be very dynamic and surprisingly diverse by its predecessor the Energetic Gamma Ray Experiment Telescope (EGRET). GLAST-LAT will have a much improved sensitivity when compared with EGRET and extend the higher energy coverage to {approx} 300 GeV. The instrument is now mounted on the spacecraft and undergoing a suite of pre-flight tests. Data analysis software has been tried out by collaborators in two rounds of 'Data Challenges' using simulated observations including backgrounds. The instrument performance and observational data on selected sources presented here have been obtained through the Data Challenges in the collaborative efforts. There are features in the GLAST-LAT observation possibly unfamiliar to X-ray astronomers: (1) GLAST will operate mostly in the survey mode; (2) the foreground objects (gas, dust, and star-light) become gamma-ray sources; (3) multiple sources will be 'confused' because of the wide point-spread-function. The last two features will pose a challenge for analysis on extended Galactic sources such as supernova remnants and pulsar wind nebulae: multi-wavelength study with X-ray instruments like Suzaku and atmospheric Chrenkov telescopes will become essential to dig out the underlying physics.

  9. Status of GLAST, the Gamma-ray Large-area Space Telescope

    SciTech Connect

    Rochester, L.; /SLAC

    2005-12-14

    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.

  10. GLAST: Exploring Nature's Highest Energy Processes with the Gamma-ray Large Area Space Telescope

    NASA Technical Reports Server (NTRS)

    Digel, Seth; Myers, J. D.; White, Nicholas E. (Technical Monitor)

    2001-01-01

    The Gamma-ray Large Area Space Telescope (GLAST) is an international and multi-agency space mission that will study the cosmos in the energy range 10 keV-300 GeV. Several successful exploratory missions in gamma-ray astronomy led to the Energetic Gamma Ray Experiment Telescope (EGRET) instrument on the Compton Gamma Ray Observatory (CGRO). Launched in 1991, EGRET made the first complete survey of the sky in the 30 MeV-10 GeV range. EGRET showed the high-energy gamma-ray sky to be surprisingly dynamic and diverse, with sources ranging from the sun and moon to massive black holes at large redshifts. Most of the gamma-ray sources detected by EGRET remain unidentified. In light of the discoveries with EGRET, the great potential of the next generation gamma-ray telescope can be appreciated. GLAST will have an imaging gamma-ray telescope vastly more capable than instruments flown previously, as well as a secondary instrument to augment the study of gamma-ray bursts. The main instrument, the Large Area Telescope (LAT), will have superior area, angular resolution, field of view, and deadtime that together will provide a factor of 30 or more advance in sensitivity, as well as provide capability for study of transient phenomena. The GLAST Burst Monitor (GBM) will have a field of view several times larger than the LAT and will provide spectral coverage of gamma-ray bursts that extends from the lower limit of the LAT down to 10 keV. The basic parameters of the GBM are compared to those of the Burst and Transient Source Experiment (BATSE) instrument on CGRO in Table 1-2. With the LAT and GBM, GLAST will be a flexible observatory for investigating the great range of astrophysical phenomena best studied in high-energy gamma rays. NASA plans to launch GLAST in late 2005.

  11. Supernova Remnants And GLAST

    SciTech Connect

    Slane, Patrick; /Harvard-Smithsonian Ctr. Astrophys.

    2011-11-29

    It has long been speculated that supernova remnants represent a major source of cosmic rays in the Galaxy. Observations over the past decade have ceremoniously unveiled direct evidence of particle acceleration in SNRs to energies approaching the knee of the cosmic ray spectrum. Nonthermal X-ray emission from shell-type SNRs reveals multi-TeV electrons, and the dynamical properties of several SNRs point to efficient acceleration of ions. Observations of TeV gamma-ray emission have confirmed the presence of energetic particles in several remnants as well, but there remains considerable debate as to whether this emission originates with high energy electrons or ions. Equally uncertain are the exact conditions that lead to efficient particle acceleration. Based on the catalog of EGRET sources, we know that there is a large population of Galactic gamma-ray sources whose distribution is similar to that of SNRs.With the increased resolution and sensitivity of GLAST, the gamma-ray SNRs from this population will be identified. Their detailed emission structure, along with their spectra, will provide the link between their environments and their spectra in other wavebands to constrain emission models and to potentially identify direct evidence of ion acceleration in SNRs. Here I summarize recent observational and theoretical work in the area of cosmic ray acceleration by SNRs, and discuss the contributions GLAST will bring to our understanding of this problem.

  12. The Capabilities of the GLAST Large Area Telescope for Blazar Variability Studies

    NASA Technical Reports Server (NTRS)

    McEnery, Julie

    2006-01-01

    One of the more notable features of the Large Area Telescope (LAT) on GLAST is its extremely large field of view, which covers more than 20% of the sky at any instant. In survey mode the LAT will be rocked about the orbital plane to provide coverage of the entire gamma-ray sky above 20 MeV every three hours. This will be the default observing mode for the first year of operations and is likely to be the dominant observing mode throughout the rest of the mission. Thus the LAT will provide long, evenly sampled, gamma-ray lightcurves for a large number of sources. In this talk we describe the nature and quality of the data that will be provided by the LAT and use simulated lightcurves to illustrate some of the scientific questions that can be addressed with LAT observations.

  13. GlastCam: A Telemetry-Driven Spacecraft Visualization Tool

    NASA Technical Reports Server (NTRS)

    Stoneking, Eric T.; Tsai, Dean

    2009-01-01

    Developed for the GLAST project, which is now the Fermi Gamma-ray Space Telescope, GlastCam software ingests telemetry from the Integrated Test and Operations System (ITOS) and generates four graphical displays of geometric properties in real time, allowing visual assessment of the attitude, configuration, position, and various cross-checks. Four windows are displayed: a "cam" window shows a 3D view of the satellite; a second window shows the standard position plot of the satellite on a Mercator map of the Earth; a third window displays star tracker fields of view, showing which stars are visible from the spacecraft in order to verify star tracking; and the fourth window depicts

  14. GLAST beam test at SLAC

    SciTech Connect

    Engovatov, D.; Anthony, P.; Atwood, W.

    1996-10-01

    In May and June, a beam test for GLAST calorimeter technologies was conducted. A parasitic low intensity electron/tagged photon beam line into the End Station A at SLAC was commissioned and used. The preliminary stage of the test was devoted to measuring the performance of the parasitic beam. In the main test we studied the response of GLAST prototype CsI and scintillating fiber calorimeters to the electrons and photons. Results of this work are discussed.

  15. The Synergy of Gamma-Ray Burst Detectors in the GLAST Era

    NASA Technical Reports Server (NTRS)

    Band, David

    2008-01-01

    Simultaneous observations by the large number of gamma-ray burst detectors that will operate in the GLAST era will provide the spectra, lightcurves and locations necessary for studying burst physics and testing the putative relations between intrinsic burst properties. I review the burst detection sensitivities, spectral bands, and localization capabilities of the GLAST (GBM and LAT), Swift (BAT), INTEGRAL (ISGRI), Suzaku (wAM), AGILE (Super-AGILE) and wind (Konus) detectors; the detectors' energy band and the accumulation timescale of their trigger system affect their sensitivity to hard vs. soft and long vs. short bursts. In addition, I estimate the rate of simultaneous burst observations. In particular, coordination of the Swift observing plan consistent with Swift's other science objectives could increase the rate of GLAST bursts with redshifts

  16. Orbital Observatory GLAST - New Step in the Study of Cosmic Gamma-Radiation

    NASA Technical Reports Server (NTRS)

    Moiseev, A. A.

    2008-01-01

    The new Gamma-ray Large Area Space Telescope (GLAST) is scheduled for launch in the middle of 2008. It contains the high energy gamma-ray telescope LAT (Large Area Telescope) which covers the energy range from 20 MeV to >300 GeV and the GMB (GLAST Burst Monitor), covering 8 keV - 30 MeV energy range. The GLAST science objectives include understanding the mechanism of charged particle acceleration in active galactic nuclei, pulsars and supernova remnants, determining the nature of the still-unidentified EGRET sources, detailed study of gamma-ray diffuse emission, high-energy emission from gamma-ray bursts and transient sources, and probing dark matter. A brief overview of the mission is given.

  17. Orbital Observatory GLAST - New Step in the Study of Cosmic Gamma Radiation: Mission Overview

    NASA Technical Reports Server (NTRS)

    Moiseev, Alexander

    2008-01-01

    This viewgraph presentation is a overview of the Gamma-ray Large Area Space Telescope (GLAST), now named Fermi Space Telescope. The new telescope is scheduled for launch in the middle of 2008. It contains the high energy gamma-ray telescope LAT (Large Area Telescope) and the GMB (GLAST Burst Monitor). The science objectives of GLAST cover almost every area of high energy astrophysics, including Active Galactic Nuclei (AGN), including Extragalactic background light (EBL), Gamma-ray bursts (GRB), Pulsars, Diffuse gamma-radiation, EGRET unidentified sources, Solar physics, Origin of Cosmic Rays and, Dark Matter and New Physics. Also included in this overview is a discussion of the preparation to the analysis of the science data.

  18. Massive Stars in Colliding Wind Systems: the GLAST Perspective

    SciTech Connect

    Reimer, Anita; Reimer, Olaf; /Stanford U., HEPL /KIPAC, Menlo Park

    2011-11-29

    Colliding winds of massive stars in binary systems are considered as candidate sites of high-energy non-thermal photon emission. They are already among the suggested counterparts for a few individual unidentified EGRET sources, but may constitute a detectable source population for the GLAST observatory. The present work investigates such population study of massive colliding wind systems at high-energy gamma-rays. Based on the recent detailed model (Reimer et al. 2006) for non-thermal photon production in prime candidate systems, we unveil the expected characteristics of this source class in the observables accessible at LAT energies. Combining the broadband emission model with the presently cataloged distribution of such systems and their individual parameters allows us to conclude on the expected maximum number of LAT-detections among massive stars in colliding wind binary systems.

  19. GLAST and Ground-Based Gamma-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    McEnery, Julie

    2008-01-01

    The launch of the Gamma-ray Large Area Space Telescope together with the advent of a new generation of ground-based gamma-ray detectors such as VERITAS, HESS, MAGIC and CANGAROO, will usher in a new era of high-energy gamma-ray astrophysics. GLAST and the ground based gamma-ray observatories will provide highly complementary capabilities for spectral, temporal and spatial studies of high energy gamma-ray sources. Joint observations will cover a huge energy range, from 20 MeV to over 20 TeV. The LAT will survey the entire sky every three hours, allowing it both to perform uniform, long-term monitoring of variable sources and to detect flaring sources promptly. Both functions complement the high-sensitivity pointed observations provided by ground-based detectors. Finally, the large field of view of GLAST will allow a study of gamma-ray emission on large angular scales and identify interesting regions of the sky for deeper studies at higher energies. In this poster, we will discuss the science returns that might result from joint GLAST/ground-based gamma-ray observations and illustrate them with detailed source simulations.

  20. Developing gamma-ray pulsar simulation tools for GLAST

    SciTech Connect

    Razzano, Massimiliano

    2007-07-12

    Pulsars are among the most intriguing sources in the gamma-ray Universe and their high-energy emission remains today quite mysterious. The Gamma-ray Large Area Space Telescope (GLAST) will study the pulsar gamma-ray emission in great detail and will discover a great number of new gamma-ray pulsars. Here are presented the latest developments of the tools that have been created for producing accurate simulations of gamma-ray pulsars emission. The main simulator is called PulsarSpectrum and can reproduce gamma-ray emission with great detail, taking also into account advanced timing effects, e.g. period increase with time, barycentric corrections and higher-order timing noise currently under development. Detailed spectral features can also be simulated with PulsarSpectrum, such as phase-dependent spectra. A suite of ancillary tools have also been built to provide a realistic pulsar population with related timing solutions. Anyway PulsarSpectrum can also simulate pulsar populations coming from external synthesis codes. All these tools are presently used within the GLAST collaboration for testing the LAT Science Analysis Environment tools and for better study of LAT capabilities for pulsar science.

  1. The Anti-Coincidence Detector for the GLAST Large Area Telescope

    SciTech Connect

    Moiseev, A.A.; Hartman, R.C.; Ormes, J.F.; Thompson, D.J.; Amato, M.J.; Johnson, T.E.; Segal, K.N.; Sheppard, D.A.

    2007-03-23

    This paper describes the design, fabrication and testing of the Anti-Coincidence Detector (ACD) for the Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT). The ACD is LAT's first-level defense against the charged cosmic ray background that outnumbers the gamma rays by 3-5 orders of magnitude. The ACD covers the top and 4 sides of the LAT tracking detector, requiring a total active area of {approx}8.3 square meters. The ACD detector utilizes plastic scintillator tiles with wave-length shifting fiber readout. In order to suppress self-veto by shower particles at high gamma-ray energies, the ACD is segmented into 89 tiles of different sizes. The overall ACD efficiency for detection of singly charged relativistic particles entering the tracking detector from the top or sides of the LAT exceeds the required 0.9997.

  2. GLAST and Suzaku: Study on Cosmic-Ray Acceleration and Interaction in the Cosmos

    NASA Astrophysics Data System (ADS)

    Kamae, T.

    The Gamma-Ray Large Area Space Telescope (GLAST) is an international and multi-agency mission scheduled for launch in the fall of 2007. The Large Area Telescope (LAT), the primary instrument of the mission, will survey the high energy sky found to be very dynamic and surprisingly diverse by its predecessor the Energetic Gamma Ray Experiment Telescope (EGRET). GLAST-LAT will have a much improved sensitivity when compared with EGRET and extend the higher energy coverage to ˜ 300 GeV. The insrument is now mounted on the spacecraft and undergoing a suite of pre-flight tests. Data analysis software has been tried out by collaborators in two rounds of ``Data Challenges'' using simulated observations including backgrounds. The instrument performance and observational data on selected sources presented here have been obtained through the Data Challenges in the collaborative efforts. There are features in the GLAST-LAT observation possibly unfamiliar to X-ray astronomers: 1) G LAST will operate mostly in the survey mode; 2) the foreground objects (gas, dust, and star-light) become gamma-ray sources; 3) multiple sources will be ``confused'' because of the wide point-spread-function. The last two features will pose a challenge for analysis on extended Galactic sources such as supernova remnants and pulsar wind nebulae: multi-wavelength study with X-ray instruments like Suzaku and atmospheric Chrenkov telescopes will become essential to dig out the underlying physics.

  3. Real-Time Visualization of Spacecraft Telemetry for the GLAST and LRO Missions

    NASA Technical Reports Server (NTRS)

    Stoneking, Eric T.; Shah, Neerav; Chai, Dean J.

    2010-01-01

    GlastCam and LROCam are closely-related tools developed at NASA Goddard Space Flight Center for real-time visualization of spacecraft telemetry, developed for the Gamma-Ray Large Area Space Telescope (GLAST) and Lunar Reconnaissance Orbiter (LRO) missions, respectively. Derived from a common simulation tool, they use related but different architectures to ingest real-time spacecraft telemetry and ground predicted ephemerides, and to compute and display features of special interest to each mission in its operational environment. We describe the architectures of GlastCam and LROCam, the customizations required to fit into the mission operations environment, and the features that were found to be especially useful in early operations for their respective missions. Both tools have a primary window depicting a three-dimensional Cam view of the spacecraft that may be freely manipulated by the user. The scene is augmented with fields of view, pointing constraints, and other features which enhance situational awareness. Each tool also has another "Map" window showing the spacecraft's groundtrack projected onto a map of the Earth or Moon, along with useful features such as the Sun, eclipse regions, and TDRS satellite locations. Additional windows support specialized checkout tasks. One such window shows the star tracker fields of view, with tracking window locations and the mission star catalog. This view was instrumental for GLAST in quickly resolving a star tracker mounting polarity issue; visualization made the 180-deg mismatch immediately obvious. Full access to GlastCam's source code also made possible a rapid coarse star tracker mounting calibration with some on the fly code adjustments; adding a fine grid to measure alignment offsets, and introducing a calibration quaternion which could be adjusted within GlastCam without perturbing the flight parameters. This calibration, from concept to completion, took less than half an hour. Both GlastCam and LROCam were

  4. Definition of a Twelve-Point Polygonal SAA Boundaryfor the GLAST Mission

    SciTech Connect

    Djomehri, Sabra I.; /UC, Santa Cruz /SLAC

    2007-08-29

    The Gamma-Ray Large Area Space Telescope (GLAST), set to launch in early 2008, detects gamma rays within a huge energy range of 100 MeV - 300 GeV. Background cosmic radiation interferes with such detection resulting in confusion over distinguishing cosmic from gamma rays encountered. This quandary is resolved by encasing GLAST's Large Area Telescope (LAT) with an Anti-Coincidence Detector (ACD), a device which identifies and vetoes charged particles. The ACD accomplishes this through plastic scintillator tiles; when cosmic rays strike, photons produced induce currents in Photomultiplier Tubes (PMTs) attached to these tiles. However, as GLAST orbits Earth at altitudes {approx}550km and latitudes between -26 degree and 26 degree, it will confront the South Atlantic Anomaly (SAA), a region of high particle flux caused by trapped radiation in the geomagnetic field. Since the SAA flux would degrade the sensitivity of the ACD's PMTs over time, a determined boundary enclosing this region need be attained, signaling when to lower the voltage on the PMTs as a protective measure. The operational constraints on such a boundary require a convex SAA polygon with twelve edges, whose area is minimal ensuring GLAST has maximum observation time. The AP8 and PSB97 models describing the behavior of trapped radiation were used in analyzing the SAA and defining a convex SAA boundary of twelve sides. The smallest possible boundary was found to cover 14.58% of GLAST's observation time. Further analysis of defining a boundary safety margin to account for inaccuracies in the models reveals if the total SAA hull area is increased by {approx}20%, the loss of total observational area is < 5%. These twelve coordinates defining the SAA flux region are ready for implementation by the GLAST satellite.

  5. Pre-launch Estimates for GLAST Sensitivity to Dark Matter Annihilation Signals

    SciTech Connect

    Baltz, E.A.; Berenji, B.; Bertone, G.; Bergstrom, L.; Bloom, E.; Bringmann, T.; Chiang, J.; Cohen-Tanugi, J.; Conrad, J.; Edmonds, Y.; Edsjo, J.; Godfrey, G.; Hughes, R.E.; Johnson, R.P.; Lionetto, A.; Moiseev, A.A.; Morselli, A.; Moskalenko, I.V.; Nuss, E.; Ormes, J.F.; Rando, R.; /INFN, Padua /Ohio State U. /Stockholm U. /Ohio State U. /Garching, Max Planck Inst., MPE /SLAC /KIPAC, Menlo Park /Ohio State U.

    2009-05-15

    We investigate the sensitivity of the Gamma-ray Large Area Space Telescope (GLAST) to indirectly detect weakly interacting massive particles (WIMPs) through the {gamma}-ray signal that their pair annihilation produces. WIMPs are among the favorite candidates to explain the compelling evidence that about 80% of the mass in the Universe is non-baryonic dark matter (DM). They are serendipitously motivated by various extensions of the standard model of particle physics such as Supersymmetry and Universal Extra Dimensions (UED). With its unprecedented sensitivity and its very large energy range (20 MeV to more than 300 GeV) the main instrument on board the GLAST satellite, the Large Area Telescope (LAT), will open a new window of discovery. As our estimates show, the LAT will be able to detect an indirect DM signature for a large class of WIMP models given a cuspy profile for the DM distribution. Using the current state of the art Monte Carlo and event reconstruction software developed within the LAT collaboration, we present preliminary sensitivity studies for several possible sources inside and outside the Galaxy. We also discuss the potential of the LAT to detect UED via the electron/positron channel. Diffuse background modeling and other background issues that will be important in setting limits or seeing a signal are presented.

  6. Simulation and Analysis of SNRs in LAT Data Challenge 2

    SciTech Connect

    Tibolla, O.; Busetto, G.; Digel, S.; Longo, F.

    2007-07-12

    In 2006 the GLAST LAT collaboration organized a detailed simulation of 55 days of the gamma-ray sky and particle background in orbit to test the simulation and analysis tools of the collaboration. For this simulation, designated Data Challenge 2 (DC2), empirical models for SNRs as gamma-ray sources in the energy range of the LAT were developed, in most cases informed by X-ray or gamma-ray observations. The development of these models and an example of analysis of one of the simulated SNRs are described here.

  7. Simulation And Analysis of SNRs in LAT Data Challenge 2

    SciTech Connect

    Tibolla, O.; Busetto, G.; Digel, S.; Longo, F.; /Trieste U. /INFN, Trieste

    2007-11-13

    In 2006 the GLAST LAT collaboration organized a detailed simulation of 55 days of the gamma-ray sky and particle background in orbit to test the simulation and analysis tools of the collaboration. For this simulation, designated Data Challenge 2 (DC2), empirical models for SNRs as gamma-ray sources in the energy range of the LAT were developed, in most cases informed by X-ray or gamma-ray observations. The development of these models and an example of analysis of one of the simulated SNRs are described here.

  8. Study of the LAT PSF of the Gamma Ray Large Area Telescope

    SciTech Connect

    Cecchi, C.; Germani, S.; Pepe, M.; Bonamente, E.; Ciprini, S.; Lubrano, P.; Tosti, G.

    2007-07-12

    GLAST is the next generation telescope for the study of the Gamma Ray Universe. The GLAST mission is composed of two instruments: the LAT (Large Area Telescope) exploring the energy range between 20 MeV and 300 GeV and the GBM (Gamma ray Burst Monitor) studying the region from 10 KeV up to 30 MeV.GLAST represents an important step beyond EGRET providing a large improvement in instrument performance: large Field of View (FOV), large energy range extending to unexplored region of energies larger than 10 GeV, large effective area, a factor of 30 improvement in sensitivity, a much smaller dead time and a very good Point Spread Function (PSF).Since GLAST will operate in a continuous scanning mode, for most of the time during the mission, photons from a source will be detected at different angles in the LAT field of view requiring a good PSF in order to disentangle between sources.We will present results on PSF studies performed with various sets of data. The selection criteria and algorithm have been initially developed on DC1 and DC2 data (simulation of one and 55 days respectively of data collected by the LAT), applied to the data collected with the 16 LAT towers during the I and T integration phase with cosmic ray muons and finally applied to the testbeam data collected in August 2006 at the CERN beam line.

  9. Future GLAST Observations of Supernova Remnants And Pulsar Wind Nebulae

    SciTech Connect

    Funk, S.; /KIPAC, Menlo Park

    2007-09-26

    Shell-type Supernova remnants (SNRs) have long been known to harbour a population of ultra-relativistic particles, accelerated in the Supernova shock wave by the mechanism of diffusive shock acceleration. Experimental evidence for the existence of electrons up to energies of 100 TeV was first provided by the detection of hard X-ray synchrotron emission as e.g. in the shell of the young SNR SN1006. Furthermore using theoretical arguments shell-type Supernova remnants have long been considered as the main accelerator of protons - Cosmic rays - in the Galaxy; definite proof of this process is however still missing. Pulsar Wind Nebulae (PWN) - diffuse structures surrounding young pulsars - are another class of objects known to be a site of particle acceleration in the Galaxy, again through the detection of hard synchrotron X-rays such as in the Crab Nebula. Gamma-rays above 100 MeV provide a direct access to acceleration processes. The GLAST Large Area telescope (LAT) will be operating in the energy range between 30 MeV and 300 GeV and will provide excellent sensitivity, angular and energy resolution in a previously rather poorly explored energy band. We will describe prospects for the investigation of these Galactic particle accelerators with GLAST.

  10. GLAST and Ground-based {gamma}-ray astronomy

    SciTech Connect

    Funk, S.; Carson, J. E.; Giebels, B.; Longo, F.; McEnery, J. E.; Paneque, D.; Reimer, O.; Reyes, L. C

    2007-07-12

    The launch of the Gamma-ray Large Area Space Telescope (GLAST) in 2007 will open the possibility of combined studies of astrophysical sources with existing ground-based VHE {gamma}-ray experiments such as H.E.S.S., VERITAS and MAGIC. Ground-based {gamma}-ray observatories provide complementary capabilities for spectral, temporal, spatial and population studies of high-energy {gamma}-ray sources. Joint observations cover a huge energy range, from 20 MeV to over 50 TeV. The LAT will survey the entire sky every three hours, allowing us to perform long-term monitoring of variable sources under uniform observation conditions and to detect flaring sources promptly. Imaging atmospheric Cherenkov telescopes (IACTs) will complement these observations with high-sensitivity pointed observations on regions of interest.

  11. GLAST and Ground-Based Gamma-Ray Astronomy

    SciTech Connect

    Funk, S.; Carson, J.E.; Giebels, B.; Longo, F.; McEnery, J.E.; Paneque, D.; Reimer, O.; Reyes, L.C.

    2007-10-10

    The launch of the Gamma-ray Large Area Space Telescope (GLAST) in 2007 will open the possibility of combined studies of astrophysical sources with existing ground-based VHE {gamma}-ray experiments such as H.E.S.S., VERITAS and MAGIC. Ground-based {gamma}-ray observatories provide complementary capabilities for spectral, temporal, spatial and population studies of high-energy {gamma}-ray sources. Joint observations cover a huge energy range, from 20 MeV to over 50 TeV. The LAT will survey the entire sky every three hours, allowing us to perform long-term monitoring of variable sources under uniform observation conditions and to detect flaring sources promptly. Imaging atmospheric Cherenkov telescopes (IACTs) will complement these observations with high-sensitivity pointed observations on regions of interest.

  12. Fabrication of the GLAST Silicon Tracker Readout Electronics

    SciTech Connect

    Baldini, Luca; Brez, Alessandro; Himel, Thomas; Johnson, R.P.; Latronico, Luca; Minuti, Massimo; Nelson, David; Sadrozinski, H.F.-W.; Sgro, Carmelo; Spandre, Gloria; Sugizaki, Mutsumi; Tajima, Hiro; Cohen Tanugi, Johann; Young, Charles; Ziegler, Marcus; /Pisa U. /INFN, Pisa /SLAC /UC, Santa Cruz

    2006-03-03

    A unique electronics system has been built and tested for reading signals from the silicon-strip detectors of the Gamma-ray Large Area Space Telescope mission. The system amplifies and processes signals from 884,736 36-cm long silicon strips in a 4 x 4 array of tower modules. An aggressive mechanical design fits the readout electronics in narrow spaces between the tower modules, to minimize dead area. This design and the resulting departures from conventional electronics packaging led to several fabrication challenges and lessons learned. This paper describes the fabrication processes and how the problems peculiar to this design were overcome.

  13. The silicon-strip tracker of the Gamma ray Large Area Space Telescope

    NASA Astrophysics Data System (ADS)

    Bellazzini, R.; Angelini, F.; Bagagli, R.; Baldini, L.; Brez, A.; Ceccanti, M.; Cohen Tanugi, J.; Kuss, M.; Latronico, L.; Massai, M. M.; Minuti, M.; Omodei, N.; Spandre, G.; Vigiani, L.; Zetti, F.

    2003-10-01

    The Gamma ray Large Area Space Telescope (GLAST) is an astro-particle mission that will study the mostly unexplored, high energy (20MeV-1TeV) spectrum of photons coming from active sources in the universe. Construction of the GLAST silicon tracker, by far the largest ever built for a space mission, is now well on the way, as it is scheduled for launch by NASA in autumn 2006. We report on the basic technology adopted for the silicon detectors, particularly in connection to their use in space, on the first results of sensors testing and on the status of tracker assembly.

  14. LAT Perspectives in Detection of High Energy Cosmic Ray Electrons

    NASA Technical Reports Server (NTRS)

    Moiseev, Alexander; Ormes, J. F.; Funk, Stefan

    2007-01-01

    The GLAST Large Area Telescope (LAT) science objectives and capabilities in the detection of high energy electrons in the energy range from 20 GeV to approx. 1 TeV are presented. LAT simulations are used to establish the event selections. It is found that maintaining the efficiency of electron detection at the level of 30% the residual hadron contamination does not exceed 2-3% of the electron flux. LAT should collect approx. ten million of electrons with the energy above 20 GeV for each year of observation. Precise spectral reconstruction with high statistics presents us with a unique opportunity to investigate several important problems such as studying galactic models of IC radiation, revealing the signatures of nearby sources such as high energy cutoff in the electron spectrum, testing the propagation model, and searching for KKDM particles decay through their contribution to the electron spectrum.

  15. The Trigger and Onboard Filter of the GLAST Large Area Telescope

    SciTech Connect

    Hughes, R.; Grove, J. E.; Kocian, M.; Ritz, S.; Russell, J. J.; Siskind, E.; Smith, P.; Usher, T.; Winer, B.

    2007-07-12

    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 the capability requires a hardware trigger and onboard software event filters that are robust and highly efficient for gamma rays while remaining powerful rejecters of the much larger fluxes of charged-particle backgrounds. Because of the important discovery windows for science and the uncertainties in the background fluxes, configuration flexibility is a particularly important system feature. This paper describes the purposes and architecture of the system, the components and capabilities of the hardware trigger and onboard software filters, and the on-orbit operations plan and expected performance.

  16. The Trigger And Onboard Filter of the GLAST Large Area Telescope

    SciTech Connect

    Hughes, R.; Grove, J.E.; Kocian, M.; Ritz, S.; Russell, J.J.; Siskind, E.; Smith, P.; Winer, B.; Usher, T.; /SLAC

    2007-11-13

    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.

  17. Fermi LAT Observations of Cosmic-Ray Electrons

    NASA Technical Reports Server (NTRS)

    Moiseev, Alexander

    2011-01-01

    Designed as a gamma-ray instrument, the LAT is a capable detector of high energy cosmic ray electrons. The LAT is composed of a 4x4 array of identical towers. Each tower has a Tracker and a Calorimeter module. Entire LAT is covered by segmented Anti-Coincidence Detector (ACD). The electron data analysis is based on that developed for photons. The main challenge is to identify and separate electrons from all other charged species, mainly CR protons (for gamma-ray analysis this is provided by the Anti-Coincidence Detector)

  18. GLAST (FERMI) Data-Processing Pipeline

    SciTech Connect

    Flath, Daniel L.; Johnson, Tony S.; Turri, Massimiliano; Heidenreich, Karen A.; /SLAC

    2011-08-12

    The Data Processing Pipeline ('Pipeline') has been developed for the Gamma-Ray Large Area Space Telescope (GLAST) which launched June 11, 2008. It generically processes graphs of dependent tasks, maintaining a full record of its state, history and data products. The Pipeline is used to automatically process the data down-linked from the satellite and to deliver science products to the GLAST collaboration and the Science Support Center and has been in continuous use since launch with great success. The pipeline handles up to 2000 concurrent jobs and in reconstructing science data produces approximately 750GB of data products using 1/2 CPU-year of processing time per day.

  19. High-redshift Gamma-Ray Burst Studies with GLAST

    SciTech Connect

    Bissaldi, Elisabetta; Longo, Francesco; Barbiellini, Guido; Calura, Francesco; Matteucci, Francesca

    2007-05-01

    We compare predicted Type Ib/c supernova (SN) rates with the observed long-duration gamma-ray burst (GRB) rates both locally and as a function of redshift. To do that, we assume different star formation histories in galaxies of different morphological type: ellipticals, spirals and irregulars. In particular, the predicted Type Ib/c SN rate (SNRIb/c) is always higher than the GRB rate, as expected, suggesting that only a small fraction (0.1-1%) of them become GRBs. We predict a ratio between the cosmic GRB rate and the cosmic SNRIb/c in the range 10-2 - 10-3, in agreement with previous estimates. Finally, due to the high star formation in spheroids at high redshift, we predict more GRBs at high redshift than previous estimates, a prediction which awaits to be proven by future observations by GLAST. Based on our studies and on the current LAT performance, an estimate of the detection possibility of this high-redshift burst population is finally presented.

  20. LAT Onboard Science: Gamma-Ray Burst Identification

    SciTech Connect

    Kuhn, Frederick; Bonnell, Jerry; Hughes, Richard; Norris, Jay; Ritz, Steven; Russell, James; Smith, Patrick; Winer, Brian; /Ohio State U.

    2007-10-15

    The main goal of the Large Area Telescope (LAT) onboard science program is to provide quick identification and localization of Gamma Ray Bursts (GRB) onboard the LAT for follow-up observations by other observatories. The GRB identification and localization algorithm will provide celestial coordinates with an error region that will be distributed via the Gamma ray burst Coordinate Network (GCN). We present results that show our sensitivity to bursts as characterized using Monte Carlo simulations of the GLAST observatory. We describe and characterize the method of onboard track determination and the GRB identification and localization algorithm. Onboard track determination is considerably different than in the onground case, resulting in a substantially altered point spread function. The algorithm contains tunable parameters which may be adjusted after launch when real bursts characteristics at very high energies have been identified.

  1. LAT Onboard Science: Gamma-Ray Burst Identification

    SciTech Connect

    Kuehn, Frederick; Hughes, Richard; Smith, Patrick; Winer, Brian; Bonnell, Jerry; Norris, Jay; Ritz, Steven; Russell, James

    2007-07-12

    The main goal of the Large Area Telescope (LAT) onboard science program is to provide quick identification and localization of Gamma Ray Bursts (GRB) onboard the LAT for follow-up observations by other observatories. The GRB identification and localization algorithm will provide celestial coordinates with an error region that will be distributed via the Gamma ray burst Coordinate Network (GCN). We present results that show our sensitivity to bursts as characterized using Monte Carlo simulations of the GLAST observatory. We describe and characterize the method of onboard track determination and the GRB identification and localization algorithm. Onboard track determination is considerably different than in the on-ground case, resulting in a substantially altered point spread function. The algorithm contains tunable parameters which may be adjusted after launch when real bursts characteristics at very high energies have been identified.

  2. Enhancing GLAST Science Through Complementary Radio Observations

    NASA Astrophysics Data System (ADS)

    Ulvestad, James S.

    2006-12-01

    Radio astronomical observations with state-of-the-art instrumentation will be critical for achieving the maximum science return from the GLAST mission. Radio nterferometers with baselines of thousands of kilometers, such as the Very Long Baseline Array (VLBA), will provide sub-milliarcsecond imaging of GLAST blazars. High-frequency VLBA imaging, repeatable at intervals of days to weeks, will image the region where gamma-ray flares occur in blazars and help determine the location of the gamma-ray emission. Multi-frequency arcsecond-scale imaging with interferometers having baselines of one to tens of kilometers, particularly the Very Large Array, will provide efficient discrimination among the candidates for unidentified gamma-ray sources. Pulsar timing with single-dish radio telescopes such as the Green Bank Telescope will enable accurate registration of gamma-ray photons with pulsar ephemerides for studies of the pulsar emission mechanisms. Along with these contemporaneous radio/GLAST observing programs, we will discuss briefly some of the recent radio programs that have been conducted in preparation for GLAST launch. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

  3. Tracker Toolkit

    NASA Technical Reports Server (NTRS)

    Lewis, Steven J.; Palacios, David M.

    2013-01-01

    This software can track multiple moving objects within a video stream simultaneously, use visual features to aid in the tracking, and initiate tracks based on object detection in a subregion. A simple programmatic interface allows plugging into larger image chain modeling suites. It extracts unique visual features for aid in tracking and later analysis, and includes sub-functionality for extracting visual features about an object identified within an image frame. Tracker Toolkit utilizes a feature extraction algorithm to tag each object with metadata features about its size, shape, color, and movement. Its functionality is independent of the scale of objects within a scene. The only assumption made on the tracked objects is that they move. There are no constraints on size within the scene, shape, or type of movement. The Tracker Toolkit is also capable of following an arbitrary number of objects in the same scene, identifying and propagating the track of each object from frame to frame. Target objects may be specified for tracking beforehand, or may be dynamically discovered within a tripwire region. Initialization of the Tracker Toolkit algorithm includes two steps: Initializing the data structures for tracked target objects, including targets preselected for tracking; and initializing the tripwire region. If no tripwire region is desired, this step is skipped. The tripwire region is an area within the frames that is always checked for new objects, and all new objects discovered within the region will be tracked until lost (by leaving the frame, stopping, or blending in to the background).

  4. Eye tracker.

    PubMed

    Pruehsner, W; Enderle, J D

    1999-01-01

    A device that records saccadic eye movements, the Eye Tracker, is presented in this paper. The Eye Tracker utilizes infra-red technology mounted on fully adjustable goggles to follow eye movements targeted by either a goggles mounted HUD type display or a wall mounted light bank. Output from the goggles is remotely sent to a PC type computer, which leads to device portability. The goggles can also maintain output data in an internal memory for latter download. The user interface is Windows based with the output from the goggles represented as a trace map or plotted points. This output can also be saved or printed for future reference. The user interface can be used on any PC type computer. The device is designed with reference to standard ISO design methodology. Safety in design and final product usage has also been addressed with reference to standard ISO type procedures. Device accuracy is maintained by precise construction of the IR units in the goggles and tight control of cross talk between each IR device plus filtering of ambient light signals. Also, a reset feature is included to maintain equal baseline control. An automatic switching device is included in the goggles to allow the Eye Tracker to "warm up," assuring that equal IR power is delivered for each subject tested. The IR units in the goggles are also modular in case replacement is required. PMID:11143354

  5. Functional analysis of glutamate transporters in excitatory synaptic transmission of GLAST1 and GLAST1/EAAC1 deficient mice.

    PubMed

    Stoffel, Wilhelm; Körner, Rafael; Wachtmann, Dagmar; Keller, Bernhard U

    2004-09-28

    The high affinity, Na(+)-dependent, electrogenic glial L-glutamate transporters GLAST1 and GLT1, and two neuronal EAAC1 and EAAT4, regulate the neurotransmitter concentration in excitatory synapses of the central nervous system. We dissected the function of the individual transporters in the monogenic null allelic mouse lines, glast1(-/-) and eaac1(-/-), and the derived double mutant glast(-/-)eaac1(-/-). Unexpectedly, the biochemical analysis and the behavioral phenotypes of these null allelic mouse lines were inconspicuous. Inhibition studies of the Na(+)-dependent glutamate transport by plasma membrane vesicles and by isolated astrocytes of wt and glast1(-/-) mouse brains indicated the pivotal compensatory role of GLT1 in the absence particularly of GLAST1 and GLAST1 and EAAC1 mutant mice. In electrophysiological studies, the decay rate of excitatory postsynaptic currents (EPSCs) of Purkinje cells (PC) after selective activation of parallel and climbing fibers proved to be similar in wt and eaac1(-/-), but was significantly prolonged in glast1(-/-) PCs. Bath application of the glutamate uptake blocker SYM2081 prolonged EPSC decay profiles in both wt and double mutant glast1(-/-)eaac1(-/-) PCs by 286% and 229%, respectively, indicating a prominent role of compensatory glutamate transport in shaping glast1(-/-)eaac1(-/-) EPSCs. PMID:15363892

  6. GLAST Burst Monitor Instrument Simulation and Modeling

    SciTech Connect

    Hoover, A. S.; Kippen, R. M.; Wallace, M. S.; Pendleton, G. N.; Fishman, G. J.; Meegan, C. A.; Kouveliotou, C.; Wilson-Hodge, C. A.; Bhat, P. N.; Briggs, M. S.; Connaughton, V.; Paciesas, W. S.; Preece, R. D.

    2008-05-22

    The GLAST Burst Monitor (GBM) is designed to provide wide field of view observations of gamma-ray bursts and other fast transient sources in the energy range 10 keV to 30 MeV. The GBM is composed of several unshielded and uncollimated scintillation detectors (twelve NaI and two BGO) that are widely dispersed about the GLAST spacecraft. As a result, reconstructing source locations, energy spectra, and temporal properties from GBM data requires detailed knowledge of the detectors' response to both direct radiation as well as that scattered from the spacecraft and Earth's atmosphere. This full GBM instrument response will be captured in the form of a response function database that is derived from computer modeling and simulation. The simulation system is based on the GEANT4 Monte Carlo radiation transport simulation toolset.

  7. Gamma-ray Astronomy and GLAST

    NASA Technical Reports Server (NTRS)

    McEnery, Julie

    2007-01-01

    The high energy gamma-ray (30 MeV to 100 GeV) sky has been relatively poorly studied. Most of our current knowledge comes from observations made by the Energetic Gamma Ray Experiment Telescope (EGRET) detector on the Compton Gamma Ray Observatory (CGRO), which revealed that the GeV gamma-ray sky is rich and vibrant. Studies of astrophysical objects at GeV energies are interesting for several reasons: The high energy gamma-rays are often produced by a different physical process than the better studied X-ray and optical emission, thus providing a unique information for understanding these sources. Production of such high-energy photons requires that charged particles are accelerated to equally high energies, or much greater. Thus gamma-ray astronomy is the study of extreme environments, with natural and fundamental connections to cosmic-ray and neutrino astrophysics. The launch of GLAST in 2008 will herald a watershed in our understanding of the high energy gamma-ray sky, providing dramatic improvements in sensitivity, angular resolution and energy range. GLAST will open a new avenue to study our Universe as well as to answer scientific questions EGRET observations have raised. In this talk, I will describe the GLAST instruments and capabilities and highlight some of the science we expect to address.

  8. High-Energy Calibration of a BGO detector of the GLAST Burst Monitor

    SciTech Connect

    Kienlin, Andreas von; Steinle, Helmut; Fishman, Gerald J.; Briggs, Michael S.; Godfrey, Gary L.

    2007-07-12

    The understanding of the instrumental response of the GLAST Burst Monitor BGO detectors at energies above the energy range which is accessible by common laboratory radiation sources (< 4.43 MeV), is important, especially for the later cross-calibration with the LAT response in the overlap region between {approx} 20 MeV to 30 MeV. In November 2006 the high-energy calibration of the GBM-BGO spare detector was performed at the small Van-de-Graaff accelerator at SLAC. High-energy gamma-rays from excited 8Be* (14.6 MeV and 17.5 MeV) and 16O* (6.1 MeV) were generated through (p, {gamma})-reactions by irradiating a LiF-target. For the calibration at lower energies radioactive sources were used. The results, including spectra, the energy/channel-relation and the dependence of energy resolution are presented.

  9. High-Energy Calibration of a BGO Detector of the GLAST Burst Monitor

    SciTech Connect

    von Kienlin, Andreas; Fishman, Gerald J.; Briggs, Michael S.; Godfrey, Gary L.; Steinle, Helmut; /Garching, Max Planck Inst., MPE

    2011-11-30

    The understanding of the instrumental response of the GLAST Burst Monitor BGO detectors at energies above the energy range which is accessible by common laboratory radiation sources (< 4.43 MeV), is important, especially for the later cross-calibration with the LAT response in the overlap region between {approx}20 MeV to 30 MeV. In November 2006 the high-energy calibration of the GBM-BGO spare detector was performed at the small Van-de-Graaff accelerator at SLAC. High-energy gamma-rays from excited {sup 8}Be* (14.6 MeV and 17.5 MeV) and {sup 16}O* (6.1 MeV) were generated through (p, {gamma})-reactions by irradiating a LiF-target. For the calibration at lower energies radioactive sources were used. The results, including spectra, the energy/channel-relation and the dependence of energy resolution are presented.

  10. Force Measurement on the GLAST Delta II Flight

    NASA Technical Reports Server (NTRS)

    Gordon, Scott; Kaufman, Daniel

    2009-01-01

    This viewgraph presentation reviews the interface force measurement at spacecraft separation of GLAST Delta II. The contents include: 1) Flight Force Measurement (FFM) Background; 2) Team Members; 3) GLAST Mission Overview; 4) Methodology Development; 5) Ground Test Validation; 6) Flight Data; 7) Coupled Loads Simulation (VCLA & Reconstruction); 8) Basedrive Simulation; 9) Findings; and 10) Summary and Conclusions.

  11. GLAST Prospects for Swift-Era Afterglows

    SciTech Connect

    Gou, L.J.; Meszaros, P.; /Penn State U.

    2011-11-23

    We calculate the GeV spectra of gamma-ray burst afterglows produced by inverse Compton scattering of these objects sub-MeV emission. We improve on earlier treatments by using refined afterglow parameters and new model developments motivated by recent Swift observations. We present time-dependent GeV spectra for standard, constant-parameter models, as well as for models with energy injection and with time-varying parameters, for a range of burst parameters. We evaluate the limiting redshift to which such afterglows can be detected by the GLAST Large Area Telescope, as well as by AGILE.

  12. Changing Horses in Midstream: Fermi LAT Computing and SCons

    NASA Astrophysics Data System (ADS)

    Bogart, J. R.; Golpayegani, N.

    2011-07-01

    (For the Fermi LAT Collaboration) Several years into GLAST (now Fermi) offline software development it became evident we would need a replacement for our original build system, the Configuration Management Tool (CMT) developed at CERN, in order to support Mac users and to keep pace with newer compilers and operating system versions on our traditional platforms, Linux and Windows. The open source product SCons emerged as the only viable alternative and development began in earnest several months before Fermi's successful launch in June of 2008. Over two years later the conversion is nearing completion. This paper describes the conversion to and our use of SCons, concentrating on the resulting environment for users and developers and how it was achieved. Topics discussed include SCons and its interaction with Fermi code, GoGui, a cross-platform gui for Fermi developers, and issues specific to Windows developer support.

  13. Explore Physics Beyond the Standard Model with GLAST

    SciTech Connect

    Lionetto, A. M.

    2007-07-12

    We give an overview of the possibility of GLAST to explore theories beyond the Standard Model of particle physics. Among the wide taxonomy we will focus in particular on low scale supersymmetry and theories with extra space-time dimensions. These theories give a suitable dark matter candidate whose interactions and composition can be studied using a gamma ray probe. We show the possibility of GLAST to disentangle such exotic signals from a standard production background.

  14. Swift Late GRB Emission and GLAST

    SciTech Connect

    Butler, Nathaniel

    2007-07-12

    Recent observations of early X-ray afterglows of GRBs by the Swift satellite - prior to t {approx} 103s but well after the end of the burst - show most GRBs to be followed by highly time and energy variable emission. This was unexpected prior to Swift and physical mechanisms remain largely mysterious. The spectra exhibit a strong hard-to-soft evolution which tracks the flux, consistent with a well-established hardness intensity correlation for the prompt Gamma-ray emission. The light curves show dramatic flares or rapid logarithmic time decays. In the simplest interpretation, this emission is GRB-like and indicates a long lived energy source with the possibility of interacting shells of widely varying bulk Lorentz factor. We review the phenomenology in order to ascertain how GLAST observations of this early emission, either detected directly or through the detection of inverse-Compton emission, can help to rule on possible models.

  15. Detection of Galactic Dark Matter by GLAST

    SciTech Connect

    Bloom, Elliott D

    1999-07-07

    The mysterious dark matter has been a subject of special interest to high energy physicists, astrophysicists and cosmologists for many years. According to theoretical models, it can make up a significant fraction of the mass of the Universe. One possible form of galactic dark matter, Weakly Interacting Massive Particles (WIMPs), could be detected by their annihilation into monoenergetic gamma-ray line(s). This paper will demonstrate that the Gamma-ray Large Area Space Telescope (GLAST), scheduled for launch in 2005 by NASA, will be capable of searching for these gamma-ray lines in the energy range from 20 GeV to {approx}500 GeV and will be sufficiently sensitive to test a number of models. The required instrument performance and its capability to reject backgrounds to the required levels are explicitly discussed.

  16. Interacting Multiview Tracker.

    PubMed

    Yoon, Ju Hong; Yang, Ming-Hsuan; Yoon, Kuk-Jin

    2016-05-01

    A robust algorithm is proposed for tracking a target object in dynamic conditions including motion blurs, illumination changes, pose variations, and occlusions. To cope with these challenging factors, multiple trackers based on different feature representations are integrated within a probabilistic framework. Each view of the proposed multiview (multi-channel) feature learning algorithm is concerned with one particular feature representation of a target object from which a tracker is developed with different levels of reliability. With the multiple trackers, the proposed algorithm exploits tracker interaction and selection for robust tracking performance. In the tracker interaction, a transition probability matrix is used to estimate dependencies between trackers. Multiple trackers communicate with each other by sharing information of sample distributions. The tracker selection process determines the most reliable tracker with the highest probability. To account for object appearance changes, the transition probability matrix and tracker probability are updated in a recursive Bayesian framework by reflecting the tracker reliability measured by a robust tracker likelihood function that learns to account for both transient and stable appearance changes. Experimental results on benchmark datasets demonstrate that the proposed interacting multiview algorithm performs robustly and favorably against state-of-the-art methods in terms of several quantitative metrics. PMID:26336117

  17. Fermi (nee GLAST) at Six Months

    NASA Technical Reports Server (NTRS)

    Ritz, Steve

    2009-01-01

    The Fermi Gamma-ray Space Telescope, formerly called GLAST, is a mission to measure the cosmic gamma-ray flux in the energy range 20 MeV to >300 GeV, with supporting measurements for gamma-ray bursts from 8 keV to 30 MeV. In addition to breakthrough capabilities in energy coverage and localization, the very large field of view enables observations of 20% of the sky at any instant, and the entire sky on a timescale of a few hours. With its recent launch on 11 June 2008, Fermi now opens a new and important window on a wide variety of phenomena, including pulsars, black holes and active galactic nuclei, gamma-ray bursts, the origin of cosmic rays and supernova remnants, and searches for hypothetical new phenomena such as supersymmetric dark matter annihilations. In addition to early results and the science opportunities, this talk includes a description of the instruments and the mission status and plans.

  18. Fermi (Formerly GLAST) at Six Months

    NASA Technical Reports Server (NTRS)

    Ritz, Steven M.

    2009-01-01

    The Fermi Gamma-ray Space Telescope, formerly called GLAST, is a mission to measure the cosmic gamma-ray flux in the energy range 20 MeV to more than 300 GeV, with supporting measurements for gamma-ray bursts from 8 keV to 30 MeV. In addition to breakthrough capabilities in energy coverage and localization, the very large field of view enables observations of 20% of the sky at any instant, and the entire sky on a timescale of a few hours. With its recent launch on 11 June 2008, Fermi now opens a new and important window on a wide variety of phenomena, including pulsars, black holes and active galactic nuclei, gamma-ray bursts, the origin of cosmic rays and supernova remnants, and searches for hypothetical new phenomena such as supersymmetric dark matter annihilations. In addition to early results and the science opportunities, this talk includes a description of the instruments and the mission status and plans.

  19. Exploring the High Energy Universe: GLAST Mission and Science

    NASA Technical Reports Server (NTRS)

    McEnery, Julie

    2007-01-01

    GLAST, the Gamma-Ray Large Area Space Telescope, is NASA's next-generation high-energy gamma-ray satellite scheduled for launch in Autumn 2007. GLAST will allow measurements of cosmic gamma-ray sources in t he 10 MeV to 100 GeV energy band to be made with unprecedented sensi tivity. Amongst its key scientific objectives are to understand part icle acceleration in Active Galactic Nuclei, Pulsars and Supernovae Remnants, to provide high resolution measurements of unidentified ga mma-ray sources, to study transient high energy emission from objects such as gamma-ray bursts, and to probe Dark Matter and the early Uni verse. Dr. McEnery will present an overview of the GLAST mission and its scientific goals.

  20. Exploring the High Energy Universe: GLAST Mission and Science

    NASA Technical Reports Server (NTRS)

    McEnery, Julie

    2007-01-01

    GLAST, the Gamma-Ray Large Area Space Telescope, is NASA's next-generation high-energy gamma-ray satellite scheduled for launch in Autumn 2007. GLAST will allow measurements of cosmic gamma-ray sources in the 10 MeV to 100 GeV energy band to be made with unprecedented sensitivity. Amongst its key scientific objectives are to understand particle acceleration in Active Galactic Nuclei, Pulsars and Supernovae Remnants, to provide high resolution measurements of unidentified gamma-ray sources, to study transient high energy emission from objects such as gamma-ray bursts, and to probe Dark Matter and the early Universe. Dr. McEnery will present an overview of the GLAST mission and its scientific goals.

  1. Finding (Or Not) New Gamma-Ray Pulsars with GLAST

    SciTech Connect

    Ransom, Scott M.; /NRAO, Charlottesville

    2011-11-29

    Young energetic pulsars will likely be the largest class of Galactic sources observed by GLAST, with many hundreds detected. Many will be unknown as radio pulsars, making pulsation detection dependent on radio and/or x-ray observations or on blind periodicity searches of the gamma-rays. Estimates for the number of pulsars GLAST will detect in blind searches have ranged from tens to many hundreds. I argue that the number will be near the low end of this range, partly due to observations being made in a scanning as opposed to a pointing mode. This paper briefly reviews how blind pulsar searches will be conducted using GLAST, what limits these searches, and how the computations and statistics scale with various parameters.

  2. Finding (or not) New Gamma-ray Pulsars with GLAST

    SciTech Connect

    Ransom, Scott M.

    2007-07-12

    Young energetic pulsars will likely be the largest class of Galactic sources observed by GLAST, with many hundreds detected. Many will be unknown as radio pulsars, making pulsation detection dependent on radio and/or x-ray observations or on blind periodicity searches of the gamma-rays. Estimates for the number of pulsars GLAST will detect in blind searches have ranged from tens to many hundreds. I argue that the number will be near the low end of this range, partly due to observations being made in a scanning as opposed to a pointing mode. This paper briefly reviews how blind pulsar searches will be conducted using GLAST, what limits these searches, and how the computations and statistics scale with various parameters.

  3. Validation of the GLAST Burst Monitor Instrument Response Simulation Software

    SciTech Connect

    Hoover, A. S.; Klimenko, A.; Kippen, R. M.; Wallace, M. S.; Pendleton, G. N.; Meegan, C. A.; Fishman, G. J.; Wilson-Hodge, C. A.; Kouveliotou, C.; Preece, R. D.; Connaughton, V.; Briggs, M. S.; Paciesas, W. S.; Bhat, P. N.

    2007-07-12

    The GLAST Burst Monitor (GBM) comprises 12 NaI and 2 BGO detectors dispersed about the GLAST spacecraft. The GBM instrument simulation software must generate an accurate response function database for all detectors in their flight configuration to optimize the mission science return. Before science analysis codes use the response database, we must confirm that our simulation codes and models can reproduce laboratory observations. To validate the simulation effort, Monte Carlo results are compared to calibrated laboratory measurements collected with a variety of radiation sources.

  4. GLAST and Dark Matter Substructure in the Milky Way

    SciTech Connect

    Kuhlen, Michael; Diemand, Juerg; Madau, Piero

    2007-07-12

    We discuss the possibility of GLAST detecting gamma-rays from the annihilation of neutralino dark matter in the Galactic halo. We have used ''Via Lactea'', currently the highest resolution simulation of cold dark matter substructure, to quantify the contribution of subhalos to the annihilation signal. We present a simulated allsky map of the expected gamma-ray counts from dark matter annihilation, assuming standard values of particle mass and cross section. In this case GLAST should be able to detect the Galactic center and several individual subhalos.

  5. GLAST observation of high-redshift GRBs

    SciTech Connect

    Bissaldi, Elisabetta; Longo, Francesco; Barbiellini, Guido; Calura, Francesco; Matteucci, Francesca; Omodei, Nicola

    2007-07-12

    We compare predicted Type Ib/c supernova (SNIb/c) rates with the observed long-duration Gamma-Ray-Burst (GRB) rates both locally and as a function of redshift, by assuming different star formation histories in galaxies of different morphological types. Due to the high star formation in spheroids at high redshift, we predict a large number of GRBs beyond z > 7. Moreover, based on our studies and on the current LAT performance, an estimate of the detection possibility of this burst population is presented.

  6. Supernova Remnants, Cosmic Rays, and GLAST

    SciTech Connect

    Reynolds, Steve

    2006-02-13

    The shock waves of supernova remnants (SNRs) are the traditional sources of Galactic cosmic rays, at least up to about 3000 TeV (the 'knee' energy in the cosmic-ray spectrum). In the last decade or so, X-ray observations have confirmed in a few SNRs the presence of synchrotron-X-ray-emitting electrons with energies of order 100 TeV. TeV photons from SNRs have been observed with ground-based air Cerenkov telescopes as well, but it is still unclear whether they are due to hadronic processes (inelastic p-p scattering of cosmic-ray protons from thermal gas, with secondary neutral pions decaying to gamma rays), or to leptonic processes (inverse-Compton upscattering of cosmic microwave background photons, or bremsstrahlung). The spatial structure of synchrotron X-rays as observed with the Chandra X-ray Observatory suggests the remarkable possibility that magnetic fields are amplified by orders of magnitude in strong shock waves. The electron spectra inferred from X-rays reach 100 TeV, but at that energy are cutting off steeply, well below the 'knee' energy. Are the cutoff processes due only to radiative losses so that ion spectra might continue unsteepened? Can we confirm the presence of energetic ions in SNRs at all? Are typical SNRs capable of supplying the pool of Galactic cosmic rays? Is strong magnetic-field amplification a property of strong astrophysical shocks in general? These major questions require the next generation of observational tools. I shall outline the theoretical and observational framework of particle acceleration to high energies in SNRs, and shall describe how GLAST will advance this field.

  7. Supernova Remnants, Cosmic Rays, and GLAST

    SciTech Connect

    Reynolds, Steve

    2006-02-13

    The shock waves of supernova remnants (SNRs) are the traditional sources of Galactic cosmic rays, at least up to about 3000 TeV (the "knee" energy in the cosmic-ray spectrum). In the last decade or so, X-ray observations have confirmed in a few SNRs the presence of synchrotron-X-ray-emitting electrons with energies of order 100 TeV. TeV photons from SNRs have been observed with ground-based air Cerenkov telescopes as well, but it is still unclear whether they are due to hadronic processes (inelastic p-p scattering of cosmic-ray protons from thermal gas, with secondary neutral pions decaying to gamma rays), or to leptonic processes (inverse-Compton upscattering of cosmic microwave background photons, or bremsstrahlung). The spatial structure of synchrotron X-rays as observed with the Chandra X-ray Observatory suggests the remarkable possibility that magnetic fields are amplified by orders of magnitude in strong shock waves. The electron spectra inferred from X-rays reach 100 TeV, but at that energy are cutting off steeply, well below the "knee" energy. Are the cutoff processes due only to radiative losses so that ion spectra might continue unsteepened? Can we confirm the presence of energetic ions in SNRs at all? Are typical SNRs capable of supplying the pool of Galactic cosmic rays? Is strong magnetic-field amplification a property of strong astrophysical shocks in general? These major questions require the next generation of observational tools. I shall outline the theoretical and observational framework of particle acceleration to high energies in SNRs, and shall describe how GLAST will advance this field.

  8. Fermi's Large Area Telescope (LAT)

    NASA Video Gallery

    Fermi’s Large Area Telescope (LAT) is the spacecraft’s main scientificinstrument. This animation shows a gamma ray (purple) entering the LAT,where it is converted into an electron (red) and a...

  9. A Catalog of Candidate High-redshift Blazars for GLAST

    SciTech Connect

    Arias, Tersi M.; /SLAC /San Francisco State U.

    2006-09-27

    High-redshift blazars are promising candidates for detection by the Gamma-ray Large Area Space Telescope (GLAST). GLAST, expected to be launched in the Fall of 2007, is a high-energy gamma-ray observatory designed for making observations of celestial gamma-ray sources in the energy band extending from 10 MeV to more than 200 GeV. It is estimated that GLAST will find several thousand blazars. The motivations for measuring the gamma-ray emission from distant blazars include the study of the high-energy emission processes occurring in these sources and an indirect measurement of the extragalactic background light. In anticipation of the launch of GLAST we have compiled a catalog of candidate high-redshift blazars. The criteria for sources chosen for the catalog were: high radio emission, high redshift, and a flat radio spectrum. A preliminary list of 307 radio sources brighter than 70mJy with a redshift z {ge} 2.5 was acquired using data from the NASA Extragalactic Database. Flux measurements of each source were obtained at two or more radio frequencies from surveys and catalogs to calculate their radio spectral indices {alpha}. The sources with a flat-radio spectrum ({alpha} {le} 0.5) were selected for the catalog, and the final catalog includes about 200 sources.

  10. ORNL SunTracker

    SciTech Connect

    Wysor, Robert Wesley

    2005-09-14

    The ORNL Sun Tracker software is the user interface that operates on a Personal Computer and serially communicates with the controller board. This software allows the user to manually operate the Hybrid Solar Lighting (HSL) unit. It displays the current location of the HSL unit, its parameters and it provides real-time monitoring. The ORNL Sun Tracker software is also the main component used in setting up and calibrating the tracker. It contains a setup screen that requires latitude, longitude, and a few other key values to accurately locate the sun's position. The software also will provide the user access to calibrate the tracking location in relation to the sun's actual position.

  11. Observation of the Milky Way with the High Energy Gamma-Ray Satellite GLAST

    NASA Astrophysics Data System (ADS)

    Mizushima, H.; Ohto, A.; Mizuno, T.; Yoshida, S.; Fukazawa, Y.; Ohsugi, T.; Ozaki, M.; Tajima, H.; Kamae, T.

    Gamma-ray observations of the universe have revealed that pulsars and Active Galactic Nuclei as well as the Milky Way are gamma-ray emitters, and thus gamma-ray observation is very important for the study of these objects. GLAST (Gamma Ray Large Area Space Telescope) is a gamma-ray satellite which will be launched in 2006. GLAST has a wide energy range, large field of view, and good angular resolution and energy resolution. In this paper, some of the scientific topics planned for GLAST are presented, in addition to the developments of the background simulator which will be necessary to analyze the GLAST data.

  12. Miniature Laser Tracker

    DOEpatents

    Vann, Charles S.

    2003-09-09

    This small, inexpensive, non-contact laser sensor can detect the location of a retroreflective target in a relatively large volume and up to six degrees of position. The tracker's laser beam is formed into a plane of light which is swept across the space of interest. When the beam illuminates the retroreflector, some of the light returns to the tracker. The intensity, angle, and time of the return beam is measured to calculate the three dimensional location of the target. With three retroreflectors on the target, the locations of three points on the target are measured, enabling the calculation of all six degrees of target position. Until now, devices for three-dimensional tracking of objects in a large volume have been heavy, large, and very expensive. Because of the simplicity and unique characteristics of this tracker, it is capable of three-dimensional tracking of one to several objects in a large volume, yet it is compact, light-weight, and relatively inexpensive. Alternatively, a tracker produces a diverging laser beam which is directed towards a fixed position, and senses when a retroreflective target enters the fixed field of view. An optically bar coded target can be read by the tracker to provide information about the target. The target can be formed of a ball lens with a bar code on one end. As the target moves through the field, the ball lens causes the laser beam to scan across the bar code.

  13. GLAST, the Gamma-ray Large Area Space Telescope

    NASA Technical Reports Server (NTRS)

    Ritz, Steven

    2007-01-01

    The Gamma-ray Large Area Space Telescope, GLAST, is a mission to measure the cosmic gamma-ray flux in the energy range 20 MeV to greater than 300 GeV, with supporting measurements for gamma-ray bursts from 10 keV to 25 MeV. With its upcoming launch in 2008, GLAST will open a new and important window on a wide variety of phenomena, including black holes and active galactic nuclei; the optical-UV extragalactic background light, gamma-ray bursts; the origin of cosmic rays and supernova remnants; and searches for hypothetical new phenomena such as supersymmetric dark matter annihilations and Lorentz invariance violation. In addition to the science opportunities, this talk includes a description of the instruments, the collaboration between particle physicists and astrophysicists, the opportunities for guest observers, and the mission status.

  14. Estimation of Electron Temperature on Glass Spherical Tokamak (GLAST)

    NASA Astrophysics Data System (ADS)

    Hussain, S.; Sadiq, M.; Shah, S. I. W.; GLAST Team

    2015-03-01

    Glass Spherical Tokamak (GLAST) is a small spherical tokamak indigenously developed in Pakistan with an insulating vacuum vessel. A commercially available 2.45 GHz magnetron is used as pre-ionization source for plasma current startup. Different diagnostic systems like Rogowski coils, magnetic probes, flux loops, Langmuir probe, fast imaging and emission spectroscopy are installed on the device. The plasma temperature inside of GLAST, at the time of maxima of plasma current, is estimated by taking into account the Spitzer resistivity calculations with some experimentally determined plasma parameters. The plasma resistance is calculated by using Ohm's law with plasma current and loop voltage as experimentally determined inputs. The plasma resistivity is then determined by using length and area of the plasma column. Finally, the average plasma electron temperature is predicted to be 12.65eV for taking neon (Ne) as a working gas.

  15. GLAST And Dark Matter Substructure in the Milky Way

    SciTech Connect

    Kuhlen, Michael; Diemand, Jurg; Madau, Piero; /UC, Santa Cruz, Astron. Astrophys. /Garching, Max Planck Inst.

    2011-11-29

    We discuss the possibility of GLAST detecting gamma-rays from the annihilation of neutralino dark matter in the Galactic halo. We have used 'Via Lactea', currently the highest resolution simulation of cold dark matter substructure, to quantify the contribution of subhalos to the annihilation signal. We present a simulated allsky map of the expected gamma-ray counts from dark matter annihilation, assuming standard values of particle mass and cross section. In this case GLAST should be able to detect the Galactic center and several individual subhalos. One of the most exciting discoveries that the Gamma-ray Large Area Space Telescope (GLAST) could make, is the detection of gamma-rays from the annihilation of dark matter (DM). Such a measurement would directly address one of the major physics problems of our time: the nature of the DM particle. Whether or not GLAST will actually detect a DM annihilation signal depends on both unknown particle physics and unknown astrophysics theory. Particle physics uncertainties include the type of particle (axion, neutralino, Kaluza-Klein particle, etc.), its mass, and its interaction cross section. From the astrophysical side it appears that DM is not smoothly distributed throughout the Galaxy halo, but instead exhibits abundant clumpy substructure, in the form of thousands of so-called subhalos. The observability of DM annihilation radiation originating in Galactic DM subhalos depends on their abundance, distribution, and internal properties. Numerical simulations have been used in the past to estimate the annihilation flux from DM substructure, but since the subhalo properties, especially their central density profile, which determines their annihilation luminosity, are very sensitive to numerical resolution, it makes sense to re-examine their contribution with higher resolution simulations.

  16. Energy calibration of Cherenkov Telescopes using GLAST data

    SciTech Connect

    Bastieri, D.; Busetto, G.; Piano, G.; Rando, R.; Saggion, A.; De Angelis, A.; Longo, F.

    2007-07-12

    We discuss the possibility of using the observations by GLAST of steady gamma sources, as the Crab Nebula and some selected AGNs, to calibrate the Imaging Air Cherenkov Telescopes (IACT) and improve their energy resolution, in particular. We show that at around 100 GeV, exploiting the features in the spectrum of the Crab Nebula, the absolute energy calibration uncertainty of Cherenkov telescopes can be reduced to < 10%.

  17. Processing GPS Receiver Data for Improved Fermi GLAST Navigation

    NASA Technical Reports Server (NTRS)

    Woodard, Mark A.

    2008-01-01

    Fermi GLAST s 5-year mission objectives: a) Explore the most extreme environments in the Universe. b) Search for signs of new laws of physics and what composes the mysterious Dark Matter. c) Explain how black holes accelerate immense jets of material to nearly light speed. d) Help crack the mysteries of gamma-ray bursts. e) Answer long-standing questions across a broad range of topics, including solar flares, pulsars and the origin of cosmic rays.

  18. Blazar Continuum Variability II: Entering the GLAST Era

    NASA Technical Reports Server (NTRS)

    Thompson, D. J.

    2005-01-01

    Intense, highly-variable gamma-ray emission from blazars was a principal discovery made with EGRET on the Compton Gamma Ray Observatory. The EGRET data remain a valuable resource for modeling of blazar astrophysics and for planning of future gamma-ray missions such as AGILE and GLAST. This presentation will review a bit of history and summarize the EGRET blazar legacy, with emphasis on work done since the end of the Compton Observatory mission.

  19. Suzaku Observations of AGN and Synergy with GLAST

    SciTech Connect

    Kataoka, Jun; Takahashi, Tad; Madejski, Greg; /KIPAC, Menlo Park

    2007-10-29

    In next five years, dramatic progress is anticipated for the AGN studies, as we have two important missions to observe celestial sources in the high energy regime: GLAST and Suzaku. Suzaku is the 5th Japanese X-ray astronomy satellite which was successfully launched in July 2005. It carries four X-ray sensitive imaging CCD cameras (0.2-12 keV) located in the focal planes of X-ray telescope, and a non-imaging, collimated hard X-ray detector, which extends the bandpass of the observatory to include the 10-600 keV range. Simultaneous monitoring observations by the two instruments (GLAST and Suzaku) will be particularly valuable for variable radio-loud AGN, allowing the cross-correlations of time series as well as detailed modeling of the spectral evolution between the X-ray and gamma-ray energy bands. In this paper, we show early highlights from Suzaku observations of radio-loud AGNs, and discuss what we can do with GLAST in forthcoming years.

  20. The Spectral Index Distribution of EGRET Blazars: Prospects for GLAST

    SciTech Connect

    Venters, Tonia M.; Pavlidou, Vasiliki; /SLAC

    2011-11-29

    The intrinsic distribution of spectral indices in GeV energies of gamma-ray-loud blazars is a critical input in determining the spectral shape of the unresolved blazar contribution to the diffuse extragalactic gamma-ray background, as well as an important test of blazar emission theories. We present a maximum-likelihood method of determining the intrinsic spectral index distribution (ISID) of a population of {gamma}-ray emitters which accounts for error in measurement of individual spectral indices, and we apply it to EGRET blazars. We find that the most likely Gaussian ISID for EGRET blazars has a mean of 2.27 and a standard deviation of 0.20. We additionally find some indication that FSRQs and BL Lacs may have different ISIDs (with BL Lacs being harder). We also test for spectral index hardening associated with blazar variability for which we find no evidence. Finally, we produce simulated GLAST spectral index datasets and perform the same analyses. With improved statistics due to the much larger number of resolvable blazars, GLAST data will help us determine the ISIDs with much improved accuracy. Should any difference exist between the ISIDs of BL Lacs and FSRQs or between the ISIDs of blazars in the quiescent and flaring states, GLAST data will be adequate to separate these ISIDs at a significance better than 3{sigma}.

  1. ORNL SunTracker

    Energy Science and Technology Software Center (ESTSC)

    2005-09-14

    The ORNL Sun Tracker software is the user interface that operates on a Personal Computer and serially communicates with the controller board. This software allows the user to manually operate the Hybrid Solar Lighting (HSL) unit. It displays the current location of the HSL unit, its parameters and it provides real-time monitoring. The ORNL Sun Tracker software is also the main component used in setting up and calibrating the tracker. It contains a setup screenmore » that requires latitude, longitude, and a few other key values to accurately locate the sun's position. The software also will provide the user access to calibrate the tracking location in relation to the sun's actual position.« less

  2. The Fermi LAT Pulsars

    NASA Astrophysics Data System (ADS)

    Romani, Roger W.

    2011-08-01

    The Large Area Telescope on the Fermi satellite is an impressive pulsar discovery machine, with over 75 pulse detections and counting. The populations of radio-selected, γ-selected and millisecond pulsars are now large enough to display observational patterns in the light curves and luminosities. These patterns are starting to teach us about the physics of the emission zone, which seems dominated by open field lines near the speed of light cylinder. The sample also provides initial inferences about the pulsar population. Apparently a large fraction of neutron stars have a young energetic γ-ray emitting phase, making these objects a good probe of massive star evolution. The long-lived millisecond γ-ray pulsars are even more ubiquitous and may produce a significant fraction of the γ-ray background. In any event, it is clear that the present LAT pulsar sample is dominated by nearby objects, and there is every expectation that the number, and quality, of pulsar detections will increase in years to come.

  3. Teaching Astronomy Using Tracker

    NASA Astrophysics Data System (ADS)

    Belloni, Mario; Christian, Wolfgang; Brown, Douglas

    2013-03-01

    A recent paper in this journal1 presented a set of innovative uses of video analysis for introductory physics using Tracker. In addition, numerous other papers have described how video analysis can be a meaningful part of introductory courses.2-4 Yet despite this, there are few resources for using video analysis in introductory astronomy classes. In this paper we describe the use of Tracker in introductory astronomy to analyze a ``video'' consisting of a series of still images of star fields and sunspots. Because astronomy focuses on concepts unfamiliar to most students, the visualization that video analysis provides can be especially valuable.

  4. Vidicon star tracker.

    PubMed

    Schuck, W H

    1966-04-01

    In many applications of star trackers, extremely short acquisition times, as well as accuracy and sensitivity, are required. Tracking systems employing the vidicon as a radiation sensor have been shown to provide the necessary speed of acquisition for such applications. This paper discusses the various theoretical and practical considerations involved in using the vidicon as a sensor in a star tracking system. A typical system configuration including telescope, sensor, and processing electronics is presented. The various optical and sensor parametric relationships required in the design of a vidicon star tracker are fully discussed and analyzed. PMID:20048884

  5. Sharper Fermi LAT images: instrument response functions for an improved event selection

    SciTech Connect

    Portillo, Stephen K. N.; Finkbeiner, Douglas P.

    2014-11-20

    The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope has a point-spread function (PSF) with large tails, consisting of events affected by tracker inefficiencies, inactive volumes, and hard scattering; these tails can make source confusion a limiting factor. The parameter CTBCORE, available in the publicly available Extended Fermi LAT data (available at http://fermi.gsfc.nasa.gov/ssc/data/access/), estimates the quality of each event's direction reconstruction; by implementing a cut in this parameter, the tails of the PSF can be suppressed at the cost of losing effective area. We implement cuts on CTBCORE and present updated instrument response functions derived from the Fermi LAT data itself, along with all-sky maps generated with these cuts. Having shown the effectiveness of these cuts, especially at low energies, we encourage their use in analyses where angular resolution is more important than Poisson noise.

  6. Teaching Astronomy Using Tracker

    ERIC Educational Resources Information Center

    Belloni, Mario; Christian, Wolfgang; Brown, Douglas

    2013-01-01

    A recent paper in this journal presented a set of innovative uses of video analysis for introductory physics using Tracker. In addition, numerous other papers have described how video analysis can be a meaningful part of introductory courses. Yet despite this, there are few resources for using video analysis in introductory astronomy classes. In…

  7. Rotational Dynamics with Tracker

    ERIC Educational Resources Information Center

    Eadkhong, T.; Rajsadorn, R.; Jannual, P.; Danworaphong, S.

    2012-01-01

    We propose the use of Tracker, freeware for video analysis, to analyse the moment of inertia ("I") of a cylindrical plate. Three experiments are performed to validate the proposed method. The first experiment is dedicated to find the linear coefficient of rotational friction ("b") for our system. By omitting the effect of such friction, we derive…

  8. MediaTracker system

    SciTech Connect

    Sandoval, D. M.; Strittmatter, R. B.; Abeyta, J. D.; Brown, J.; Marks, T. , Jr.; Martinez, B. J.; Jones, D. B.; Hsue, W.

    2004-01-01

    The initial objectives of this effort were to provide a hardware and software platform that can address the requirements for the accountability of classified removable electronic media and vault access logging. The Media Tracker system software assists classified media custodian in managing vault access logging and Media Tracking to prevent the inadvertent violation of rules or policies for the access to a restricted area and the movement and use of tracked items. The MediaTracker system includes the software tools to track and account for high consequence security assets and high value items. The overall benefits include: (1) real-time access to the disposition of all Classified Removable Electronic Media (CREM), (2) streamlined security procedures and requirements, (3) removal of ambiguity and managerial inconsistencies, (4) prevention of incidents that can and should be prevented, (5) alignment with the DOE's initiative to achieve improvements in security and facility operations through technology deployment, and (6) enhanced individual responsibility by providing a consistent method of dealing with daily responsibilities. In response to initiatives to enhance the control of classified removable electronic media (CREM), the Media Tracker software suite was developed, piloted and implemented at the Los Alamos National Laboratory beginning in July 2000. The Media Tracker software suite assists in the accountability and tracking of CREM and other high-value assets. One component of the MediaTracker software suite provides a Laboratory-approved media tracking system. Using commercial touch screen and bar code technology, the MediaTracker (MT) component of the MediaTracker software suite provides an efficient and effective means to meet current Laboratory requirements and provides new-engineered controls to help assure compliance with those requirements. It also establishes a computer infrastructure at vault entrances for vault access logging, and can accommodate

  9. The LHCb silicon tracker

    NASA Astrophysics Data System (ADS)

    Adeva, B.; Agari, M.; Bauer, C.; Baumeister, D.; Bay, A.; Bernhard, R. P.; Bernet, R.; Blouw, J.; Carron, B.; Ermoline, Y.; Esperante, D.; Frei, R.; Gassner, J.; Hofmann, W.; Jimenez-Otero, S.; Knöpfle, K. T.; Köstner, S.; Lehner, F.; Löchner, S.; Lois, C.; Needham, M.; Pugatch, V.; Schmelling, M.; Schwingenheuer, B.; Siegler, M.; Steinkamp, O.; Straumann, U.; Tran, M. T.; Vazquez, P.; Vollhardt, A.; Volyanskyy, D.; Voss, H.

    2005-07-01

    LHCb is a dedicated B-physics and CP-violation experiment for the Large Hadron Collider at CERN. Efficient track reconstruction and excellent trigger performances are essential in order to exploit fully its physics potential. Silicon strip detectors providing fast signal generation, high resolution and fine granularity are used for this purpose in the large area Trigger Tracker station in front of the spectrometer magnet and the LHCb Inner Tracker covering the area close to the beam pipe behind the magnet. Long read-out strips of up to 38 cm are used together with fast signal shaping adapted to the 25 ns LHC bunch crossing. The design of these tracking stations, the silicon sensor strip geometries and the latest test results are presented here.

  10. The Tevatron Chromaticity tracker

    SciTech Connect

    Tan, Cheng-Yang; /Fermilab

    2008-12-01

    The Tevatron chromaticity tracker (CT) has been successfully commissioned and is now operational. The basic idea behind the CT is that when the phase of the Tevatron RF is slowly modulated, the beam momentum is also modulated. This momentum modulation is coupled transversely via chromaticity to manifest as a phase modulation on the betatron tune. Thus by phase demodulating the betatron tune, the chromaticity can be recovered. However, for the phase demodulation to be successful, it is critical that the betatron tune be a coherent signal that can be easily picked up by a phase detector. This is easily done because the Tevatron has a phase locked loop (PLL) based tune tracker which coherently excites the beam at the betatron tune.

  11. The Burst Monitor (GBM) on-board GLAST

    NASA Astrophysics Data System (ADS)

    Georgii, R.

    The Gamma-ray Large-Area Space Telescope (GLAST) will be the next major NASA mission for high-energy γ-ray astronomy after EGRET. Presently the launch is foreseen for the end of 2005. Its scientific objective will be to observe AGNs, pulsars, SN remnants and interactions of cosmic rays with the interstellar medium from 10 MeV to 300 GeV. Another important objective will be the study of γ-ray burst spectra and time profiles at the high-energy end. A Burst Monitor ((GBM) will be on board of GLAST and will be built, by a collaboration of MSFC/UAH and the MPE, to enhance the γ-ray burst-detection capability of GLAST considerably. It will measure burst spectra between 5 keV and 30 MeV with an energy resolution between ≈3% (at 20 MeV) and ≈50% (at 5 keV). Thus an energy range of more than 6 decades will be accessible in burst spectra for the first time. Moreover it will measure the light curves with an absolute time accuracy of 10 μsec. Furthermore the GBM will provide an on-board position to the main instrument for repointing purposes, allowing for an observation of a burst with the main telescope within 10 minutes. Through an energy range similar to that of BASTE continuity with the large data base of γ-ray burst-spectra parameters can be achieved, putting the expected high-energy emission in a better context. In this talk the scientific goals of the GBM and its technical realisation will be presented.

  12. The LHCb Silicon Tracker

    NASA Astrophysics Data System (ADS)

    Tobin, Mark

    2013-12-01

    The LHCb experiment is designed to perform high-precision measurements of CP violation and search for new physics using the enormous flux of beauty and charm hadrons produced at the LHC. The LHCb detector is a single-arm spectrometer with excellent tracking and particle identification capabilities. The Silicon Tracker is part of the tracking system and measures very precisely the particle trajectories coming from the interaction point in the region of high occupancies around the beam axis. The LHCb Silicon Tracker covers a total sensitive area of about 12 m2 using silicon micro-strip detectors with long readout strips. It consists of one four-layer tracking station before the LHCb dipole magnet and three stations after. The detector has performed extremely well since the start of the LHC operation despite the fact that the experiment is collecting data at instantaneous luminosities well above the design value. This paper reports on the operation and performance of the Silicon Tracker during the Physics data taking at the LHC during the last two years.

  13. The Origin of Cosmic Rays: What can GLAST Say?

    NASA Technical Reports Server (NTRS)

    Ormes, Jonathan F.; Digel, Seith; Moskalenko, Igor V.; Moiseev, Alexander; Williamson, Roger

    2000-01-01

    Gamma rays in the band from 30 MeV to 300 GeV, used in combination with direct measurements and with data from radio and X-ray bands, provide a powerful tool for studying the origin of Galactic cosmic rays. Gamma-ray Large Area Space Telescope (GLAST) with its fine 10-20 arcmin angular resolution will be able to map the sites of acceleration of cosmic rays and their interactions with interstellar matter, It will provide information that is necessary to study the acceleration of energetic particles in supernova shocks, their transport in the interstellar medium and penetration into molecular clouds.

  14. GLAST and GRBs: Probing Photon Propagation over cosmological distances

    SciTech Connect

    Longo, Francesco; Omodei, Nicola; Cohen-Tanugi, Johann; Scargle, Jeff D.; Piron, Frederic

    2006-05-19

    Especially in the framework of Quantum Gravity, it is theoretically possible that photons of different energy propagate at different velocity. Gamma-ray Bursts (GRBs), due to their large distances and rapid variability in a broad energy band, are perhaps the best astronomical sources in which to measure any such dispersion over cosmological distances. GLAST will detect several GRBs per year at GeV energies, where the effect may be detectable. We address problems of optimal sensitivity and discrimination against energy-dependent effects intrinsic to GRB emission, using simulated data and new unbinned lag-detection algorithms.

  15. Viewing the Violent Universe with SWIFT and GLAST

    NASA Technical Reports Server (NTRS)

    Thompson, David J.

    2005-01-01

    As the most energetic form of light, gamma rays help reveal information about some of the most violent phenomena in the Universe. Previous space missions like the Compton Gamma Ray Observatory provided the observations that set the stage for two 21st century gamma-ray programs. Swift, launched in Fall, 2004, concentrates on gamma-ray bursts, the most powerful explosions in the Universe. GLAST, the Gamma-ray Large Area Space Telescope, will be launched in 2007 to study objects like blazars, pulsars, supernovae, and unidentified sources.

  16. The Synergy of Gamma-Ray Burst Detectors In The Glast Era

    NASA Technical Reports Server (NTRS)

    Band, David L.

    2008-01-01

    Simultaneous observations by the large number of gamma-ray burst detectors operating in the GLAST era will provide the spectra, lightcurves and locations necessary for studying burst physics and testing the putative relations between intrinsic burst properties. The detectors' energy band and the accumulation timescale of their trigger system affect their sensitivity to hard vs. soft and long vs. short bursts. Coordination of the Swift and GLAST observing plans consistent with Swift's other science objectives could increase the rate of GLAST bursts with redshifts.

  17. Instrument Response Modeling and Simulation for the GLAST Burst Monitor

    SciTech Connect

    Kippen, R. M.; Hoover, A. S.; Wallace, M. S.; Pendleton, G. N.; Meegan, C. A.; Fishman, G. J.; Wilson-Hodge, C. A.; Kouveliotou, C.; Preece, R. D.; Connaughton, V.; Briggs, M. S.; Paciesas, W. S.; Bhat, P. N.

    2007-07-12

    The GLAST Burst Monitor (GBM) is designed to provide wide field of view observations of gamma-ray bursts and other fast transient sources in the energy range 10 keV to 30 MeV. The GBM is composed of several unshielded and uncollimated scintillation detectors (twelve NaI and two BGO) that are widely dispersed about the GLAST spacecraft. As a result, reconstructing source locations, energy spectra, and temporal properties from GBM data requires detailed knowledge of the detectors' response to both direct radiation as well as that scattered from the spacecraft and Earth's atmosphere. This full GBM instrument response will be captured in the form of a response function database that is derived from computer modeling and simulation. The simulation system is based on the GEANT4 Monte Carlo radiation transport simulation toolset, and is being extensively validated against calibrated experimental GBM data. We discuss the architecture of the GBM simulation and modeling system and describe how its products will be used for analysis of observed GBM data. Companion papers describe the status of validating the system.

  18. MAXI and GLAST Studies of Jets in Active Galaxies

    SciTech Connect

    Madejski, Greg; Kataoka, Jun; Sikora, Marek

    2008-10-13

    The recent launch of GLAST--coinciding with the MAXI workshop--opens a new era for studies of jet-dominated active galaxies, known as blazars. While the emission processes operating in various spectral bands in blazars are reasonably well understood, the knowledge of the details of the structure of the jet, location of the dissipation region with respect to the accreting black hole, and coupling of the jet to the accretion process are known only at a rudimentary level. Blazars are variable, and this provides an opportunity to use the variability in various bands--and in particular, the relationship of respective time series to each other--to explore the relative location of regions responsible for emission in the respective bands. Observationally, this requires well-sampled time series in as many spectral bands as possible. To this end, with its all-sky, sensitive monitoring capability, the recently launched GLAST, and MAXI, to be deployed in 2009, are the most promising instruments bound to provide good sampling in respectively the energetic gamma-ray, and the soft X-ray band. This paper highlights the inferences regarding blazar jets that can be gleaned from such joint observations.

  19. CMS tracker visualization tools

    NASA Astrophysics Data System (ADS)

    Mennea, M. S.; Osborne, I.; Regano, A.; Zito, G.

    2005-08-01

    This document will review the design considerations, implementations and performance of the CMS Tracker Visualization tools. In view of the great complexity of this sub-detector (more than 50 millions channels organized in 16540 modules each one of these being a complete detector), the standard CMS visualization tools (IGUANA and IGUANACMS) that provide basic 3D capabilities and integration within CMS framework, respectively, have been complemented with additional 2D graphics objects. Based on the experience acquired using this software to debug and understand both hardware and software during the construction phase, we propose possible future improvements to cope with online monitoring and event analysis during data taking.

  20. Tracker 300 Software

    SciTech Connect

    Wysor, R. Wes

    2006-01-12

    The Tracker300 software is downloaded to an off-the-shelf product called RCM3400/RCM3410 made by Rabbit Semiconductor. The software is a closed loop control which computes the sun's position and provides stability compensation. Using the RCM3400/RCM3410 module, the software stores and retrieves parameters from the onboard flash. The software also allows for communication with a host. It will allow the parameters to be downloaded or uploaded, it will show the status of the controller, it will provide real-time feedback, and it will send command acknowledgements. The software will capture the GPS response and ensure the internal clock is set correctly.

  1. GLAST Burst Monitor On-Board Triggering, Locations and Event Classification

    SciTech Connect

    Briggs, M. S.; Connaughton, V.; Paciesas, W.; Preece, R.; Meegan, C. A.; Fishman, G.; Kouveliotou, C.; Wilson-Hodge, C.; Diehl, R.; Greiner, J.; Kienlin, A. von; Lichti, G.; Steinle, H.; Kippen, R. M.

    2007-07-12

    We report on how the the GLAST Burst Monitor (GBM) Flight Software will detect gamma-ray rate increases, a process known as 'triggering', and on how the Flight Software will locate and classify the causes of the triggers.

  2. Recent HiLat results

    NASA Astrophysics Data System (ADS)

    Fremouw, E. J.

    1985-11-01

    The Defense Nuclear Agency (DNA) HiLat Satellite was launched on 27 June 1983 for the purpose of studying the development and dynamics of F-layer irregularities between the plasmapause and the pole. In a circular 800-km orbit at 82 inclination, it carries (1) a coherent radio beacon for measuring complex-signal scintillation and TEC, (2) a three-instrument thermal-plasma experiment consisting of a Langmuiare probe (debilitated on launch), a retarding-potential analyzer (RPA), and an ion drift meter; (3) an energetic-electron spectrometer operating between 20 ev and 20 kev, (4) a three-axis fluxgate magnetometer, and (5) an optical package consisting of a vacuum-ultraviolet (vuv) imaging spectrophometer (failed after collecting forty orbits of data) and two visible-wavelength telephotometers. All instruments other than the Langmuire probe and the vuv imager continue to operate reliably. To date, HiLat has returned the following three specific observations of note: first auroral image in full daylight, most intense field-aligned current flowing into the ionsophere, and energy-dispersed electron precipitation impulses with about a one-second periodicity. These observations and on-going analyses of HiLat's bulk data base are summarized.

  3. Search for GLAST gamma ray burst triggers due to particle precipitation in the South Atlantic Anomaly

    SciTech Connect

    Augusto, C. R. A.; Navia, C. E.; Tsui, K. H.

    2008-10-15

    When GLAST is in the South Atlantic Anomaly (SAA), the rate of charged particles is too high to be efficiently filtered out. Moreover the high rate can cause saturation effects in the readout electronics and the sensors must be turned off. The SAA area relative to the total area of GLAST's orbit is approximately 12.5% and GLAST spends 18% of the time in it. In spite of these cares, we show in this work that, due to drift processes, particle precipitation can still trigger GLAST when it is close to the SAA region. Here, we report two GLAST gamma ray burst monitor (GBM) triggers, trigger 239895229 and trigger 239913100, on August, 08, 2008 whose characteristics are similar to the ones observed in the Swift-BAT noise triggers (due to particle precipitation in the SAA region). Both GLAST triggers happened during a plentiful particle precipitation in the SAA region, observed by Tupi telescopes at the ground with their trigger coordinates close to the field of view of the telescopes. Details of these results are reported.

  4. BKGE: Fermi-LAT Background Estimator

    NASA Astrophysics Data System (ADS)

    Vasileiou, Vlasios

    2014-11-01

    The Fermi-LAT Background Estimator (BKGE) is a publicly available open-source tool that can estimate the expected background of the Fermi-LAT for any observational conguration and duration. It produces results in the form of text files, ROOT files, gtlike source-model files (for LAT maximum likelihood analyses), and PHA I/II FITS files (for RMFit/XSpec spectral fitting analyses). Its core is written in C++ and its user interface in Python.

  5. Fermi-LAT detection of increased gamma-ray activity from the blazar PKS 0727-115

    NASA Astrophysics Data System (ADS)

    Horan, D.; Hays, E. Gurwell, Mark A.

    2009-01-01

    The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope (formerly GLAST, launched June 11, 2008), has observed an increasing gamma-ray flux from a source positionally consistent with PKS 0727-115 (RA: 07h30m19.1s, Dec: -11d41m13s, J2000, z=1.59 ( Zensus et al. 2002)). Preliminary analysis indicates that over the past month the source has become, on average, brighter with a gamma-ray flux (E>100MeV) of approximately 5.0+/- 0.8 x 10^-7 photons cm^-2 s^-1 on weekly timescales and occasional day-scale detections at the level of approximately 4.0 +/- 1.0 x 10^-7 photons cm^-2 s^-1.

  6. Tracker 300 Software

    Energy Science and Technology Software Center (ESTSC)

    2006-01-12

    The Tracker300 software is downloaded to an off-the-shelf product called RCM3400/RCM3410 made by Rabbit Semiconductor. The software is a closed loop control which computes the sun's position and provides stability compensation. Using the RCM3400/RCM3410 module, the software stores and retrieves parameters from the onboard flash. The software also allows for communication with a host. It will allow the parameters to be downloaded or uploaded, it will show the status of the controller, it will providemore » real-time feedback, and it will send command acknowledgements. The software will capture the GPS response and ensure the internal clock is set correctly.« less

  7. Silicon tracker data acquisition

    SciTech Connect

    Haynes, W.J.

    1997-12-31

    Large particle physics experiments are making increasing technological demands on the design and implementation of real-time data acquisition systems. The LHC will have bunch crossing intervals of 25 nanoseconds and detectors, such as CMS, will contain over 10 million electronic channels. Readout systems will need to cope with 100 kHz rates of 1 MByte-sized events. Over 70% of this voluminous flow will stem from silicon tracker and MSGC devices. This paper describes the techniques currently being harnessed from ASIC devices through to modular microprocessor-based architectures around standards such as VMEbus and PCI. In particular, the experiences gained at the HERA H1 experiment are highlighted where many of the key technological concepts have already been im implemented.

  8. Intelligent star tracker

    NASA Astrophysics Data System (ADS)

    Clark, Natalie

    2001-11-01

    Current state-of-the-art commercial star sensors typically weigh 15 pounds, attain 5 to 10 arc-second accuracy, and use roughly 10 watts of power. Unfortunately, the current state-of-the-art commercial star sensors do not meet many of NASA's next-generation spacecraft and instrument needs. Nor do they satisfy Air Force's needs for micro/nano-satellite systems. In an effort to satisfy micro/nano satellite mission needs the Air Force Research Laboratory is developing an intelligent star Tracker, called IntelliStar, which incorporates several novel technologies including Silicon carbide optical housing, MEMs based adaptive optic technologies, smart active pixels, and algebraic coding theory. The design considerations associated with the development of the IntelliStar system are presented along with experimental results which characterize each technologies contribution to overall system performance. In addition to being light weight, the IntelliStar System offers advantages in speed, size, power consumption, and radiation tolerance.

  9. Synergy Between Observations of AGN with GLAST and MAXI

    SciTech Connect

    Madejski, Grzegorz

    2002-03-25

    In five years' time we will witness the launch of two important missions developed to observe celestial sources in the high energy regime: GLAST, sensitive in the high energy {gamma}-ray band, and MAXI, the all-sky X-ray monitor. Simultaneous monitoring observations by the two instruments will be particularly valuable for variable sources, allowing cross-correlations of time series between the two bands. We present the anticipated results from such observations of active galaxies, and in particular, of the jet-dominated sub-class of AGN known as blazars. We discuss the constraints on the structure and emission processes--and in particular, on the internal shock models currently invoked to explain the particle acceleration processes in blazars--that can be derived with simultaneous {gamma}-ray and X-ray data.

  10. Optical Observations Of Fermi LAT Monitored Blazars

    NASA Astrophysics Data System (ADS)

    Cook, Kyle; Carini, M. T.

    2009-01-01

    For the past 8 years the Bell Observatory at Western Kentucky University has been conducting R band monitoring of the variability of approximately 50 Blazars. A subset of these objects are being routinely observed with the LAT instrument on-board the Fermi Space Telescope. Adding the Robotically Controlled Telescope (RCT) at Kitt Peak National Observatory and observations with the AZT-11 telescope at the Crimean Astrophysical Observatory (CRAO), we are intensively monitoring the Blazars on the Lat monitoring list. We present the results of our long term monitoring of the LAT monitored Blazars, as well as the recent contemporaneous optical R band observations we have obtained of the LAT Blazars.

  11. STAR heavy flavor tracker

    NASA Astrophysics Data System (ADS)

    Qiu, Hao

    2014-11-01

    Hadrons containing heavy quarks are a clean probe of the early dynamic evolution of the dense and hot medium created in high-energy nuclear collisions. To explore heavy quark production at RHIC, the Heavy Flavor Tracker (HFT) for the STAR experiment was built and installed in time for RHIC Run 14. The HFT consists of four layers of silicon detectors. The two outermost layers are silicon strip detectors and the two innermost layers are made from state-of-the-art ultra-thin CMOS Monolithic Active Pixel Sensors (MAPS). This is the first application of a CMOS MAPS detector in a collider experiment. The use of thin pixel sensors plus the use of carbon fiber supporting material limits the material budget to be only 0.4% radiation length per pixel detector layer, enabling the reconstruction of low pT heavy flavor hadrons. The status and performance of the HFT in the RHIC 200 GeV Au + Au run in 2014 are reported. Very good detector efficiency, hit residuals and track resolution (DCAs) were observed in the cosmic ray data and in the Au + Au data.

  12. WGM Temperature Tracker

    NASA Technical Reports Server (NTRS)

    Strekalov, Dmitry V.

    2012-01-01

    This software implements digital control of a WGM (whispering-gallerymode) resonator temperature based on the dual-mode approach. It comprises one acquisition (dual-channel) and three control modules. The interaction of the proportional-integral loops is designed in the original way, preventing the loops from fighting. The data processing is organized in parallel with the acquisition, which allows the computational overhead time to be suppressed or often completely avoided. WGM resonators potentially provide excellent optical references for metrology, clocks, spectroscopy, and other applications. However, extremely accurate (below micro-Kelvin) temperature stabilization is required. This software allows one specifically advantageous method of such stabilization to be implemented, which is immune to a variety of effects that mask the temperature variation. WGM Temperature Tracker 2.3 (see figure) is a LabVIEW code developed for dual-mode temperature stabilization of WGM resonators. It has allowed for the temperature stabilization at the level of 200 nK with one-second integration time, and 6 nK with 10,000-second integration time, with the above room-temperature set point. This software, in conjunction with the appropriate hardware, can be used as a noncryogenic temperature sensor/ controller with sub-micro-Kelvin sensitivity, which at the time of this reporting considerably outperforms the state of the art.

  13. Controls Request Tracker

    SciTech Connect

    White, Karen S; Kasemir, Kay; Hartman, Steven M; Verstovsek, Igor

    2009-01-01

    Controls groups at large accelerators are routinely called upon to build and support controls for virtually all machine systems. While construction projects within the US DOE system are normally carefully planned and tracked by project management professionals, this support ends when construction milestones are met. However, once construction is complete, work continues as the group performs ongoing support and maintenance while also implementing requested system improvements and upgrades. With customers from virtually every accelerator and experiment group, the demands on the group often exceed the capacity of available resources. This type of diverse workload needs to be well organized and managed in order set proper priorities and ensure efficient use of resources. At SNS, we have collaborated with Cosylab to develop Controls Request Tracker (CRT), which is adapted from the Cosylab Project Manager (CPM) software. The resulting system not only provides standard request tracking features, but is interfaced to the SNS Logbook and work control system. This paper will discuss CRT and how we use it to manage the work of our controls group.

  14. Schedule-Tracker Computer Program

    NASA Technical Reports Server (NTRS)

    Collazo, Fernando F.

    1990-01-01

    Schedule Tracker provides effective method for tracking tasks "past due" and/or "near term". Generates reports for each responsible staff member having one or more assigned tasks falling within two listed categories. Schedule Organizer (SO) (COSMIC program MSC-21525), Schedule Tracker (ST), and Schedule Report Generator (SRG) (COSMIC program MSC-21527) computer programs manipulating data-base files in ways advantageous in scheduling. Written in PL/1 and DEC Command Language (DCL).

  15. P07.04PROMOTER METHYLATION OF THE LATS1 AND LATS2 GENES IN SCHWANNOMAS

    PubMed Central

    Ohta, T.; Oh, J.; Mittelbronn, M.; Paulus, W.; Ohgaki, H.

    2014-01-01

    Schwannoma is a benign nerve sheath tumor that is typically encapsulated and composed of well-differentiated Schwann cellswhich comprises 5-10% of all intracranial tumors in adults. Approximately 90% of schwannomas are solitary and sporadic, whereas ∼4% are considered to arise in the setting of neurofibromatosis type 2 (NF2) syndrome by NF2 germline mutations. The molecular basis of sporadic schwannomas is not fully understood, other than frequent NF2 mutations (∼60%). LATS1 and the related LATS2 are downstream molecules of NF2 and negative regulators of the YAP oncogene in the Salvador/Warts/Hippo (SWH) signaling pathway. Expression of these genes is reduced due to promoter methylation in a variety of neoplasms including gliomas. In the present study, methylation-specific PCR revealed promoter methylation of the LATS1 and LATS2 in 15 of 91 (16%) and 32 of 91 (35%) schwannomas, respectively. These alterations were significantly more frequent in spinal than in peripheral schwannomas (23% vs 3% for LATS1, P = 0.0171; 42% vs 21% for LATS2, P = 0.0386). LATS1 methylation was also detected in 3 of 4 schwannomatosis cases. Furthermore, neurofibroma / schwannoma hybrid tumors showed promoter methylation in LATS1 (3/14; 21%) and LATS2 (8/14; 57%). LATS1 and LATS2 promoter methylation were largely mutually exclusive, and there was a significant negative correlation (P = 0.003); only 10 cases had methylation in both genes. These results suggest that LATS1 and LATS2 promoter methylation may be additional molecular mechanisms resulting in an abnormal SWH pathway in schwannomas and related tumors.

  16. Digging for the Truth: Photon Archeology with GLAST

    SciTech Connect

    Stecker, F. W.

    2007-07-12

    Stecker, Malkan and Scully, have shown how ongoing deep surveys of galaxy luminosity functions, spectral energy distributions and backwards evolution models of star formation rates can be used to calculate the past history of intergalactic photon densities for energies from 0.03 eV to the Lyman limit at 13.6 eV and for redshifts out to 6 (called here the intergalactic background light or IBL). From these calculations of the IBL at various redshifts, they predict the present and past optical depth of the universe to high energy {gamma}-rays owing to interactions with photons of the IBL and the 2.7 K CMB. We discuss here how this proceedure can be reversed by looking for sharp cutoffs in the spectra of extragalactic {gamma}-ray sources such as blazars at high redshifts in the multi-GeV energy range with GLAST (Gamma-Ray Large Are Space Telescope). By determining the cutoff energies of sources with known redshifts, we can refine our determination of the IBL photon densities in the past, i.e., the archeo-IBL, and therefore get a better measure of the past history of the total star formation rate. Conversely, observations of sharp high energy cutoffs in the {gamma}-ray spectra of sources at unknown redshifts can be used instead of spectral lines to give a measure of their redshifts.

  17. Hyperspectral Imager-Tracker

    NASA Technical Reports Server (NTRS)

    Agurok, Llya

    2013-01-01

    The Hyperspectral Imager-Tracker (HIT) is a technique for visualization and tracking of low-contrast, fast-moving objects. The HIT architecture is based on an innovative and only recently developed concept in imaging optics. This innovative architecture will give the Light Prescriptions Innovators (LPI) HIT the possibility of simultaneously collecting the spectral band images (hyperspectral cube), IR images, and to operate with high-light-gathering power and high magnification for multiple fast- moving objects. Adaptive Spectral Filtering algorithms will efficiently increase the contrast of low-contrast scenes. The most hazardous parts of a space mission are the first stage of a launch and the last 10 kilometers of the landing trajectory. In general, a close watch on spacecraft operation is required at distances up to 70 km. Tracking at such distances is usually associated with the use of radar, but its milliradian angular resolution translates to 100- m spatial resolution at 70-km distance. With sufficient power, radar can track a spacecraft as a whole object, but will not provide detail in the case of an accident, particularly for small debris in the onemeter range, which can only be achieved optically. It will be important to track the debris, which could disintegrate further into more debris, all the way to the ground. Such fragmentation could cause ballistic predictions, based on observations using high-resolution but narrow-field optics for only the first few seconds of the event, to be inaccurate. No optical imager architecture exists to satisfy NASA requirements. The HIT was developed for space vehicle tracking, in-flight inspection, and in the case of an accident, a detailed recording of the event. The system is a combination of five subsystems: (1) a roving fovea telescope with a wide 30 field of regard; (2) narrow, high-resolution fovea field optics; (3) a Coude optics system for telescope output beam stabilization; (4) a hyperspectral

  18. Gamma-Ray Burst observations with GLAST and TeV observatories

    SciTech Connect

    Longo, F. |; McEnery, J.; Omodei, N.; Bastieri, D.; Piron, F.

    2007-07-12

    The Gamma-Ray Large Area Space Telescope (GLAST), scheduled to be launched in 2007, will provide the capability to observe Gamma-Ray Bursts (GRB) from 10 keV to more than 300 GeV. The spectral and temporal properties of GRBs above a few GeV are still almost unknown, extending these detections to higher energies with GLAST will have a large impact on our knowledge of the particle acceleration and emission processes occuring within these sources. In this work we review the requirements and the opportunities for good coordination of GLAST with ground-based telescopes operating above a few tens of GeV, and examine the potential of such simultaneous observations in terms of expected rates of alerts.

  19. Simulation of Prompt Emission from GRBs with a Photospheric Component and its Detectability by GLAST

    SciTech Connect

    Battelino, Milan; Ryde, Felix; Omodei, Nicola; Longo, Francesco

    2007-05-01

    The prompt emission from gamma-ray bursts (GRBs) still requires a physical explanation. Studies of time-resolved GRB spectra, observed in the keV-MeV range, show that a hybrid model consisting of two components, a photospheric and a non-thermal component, in many cases fits bright, single-pulsed bursts as well as, and in some instances even better than, the Band function. With an energy coverage from 8 keV up to 300 GeV, GLAST will give us an unprecedented opportunity to further investigate the nature of the prompt emission. In particular, it will give us the possibility to determine whether a photospheric component is the determining feature of the spectrum or not. Here we present a short study of the ability of GLAST to detect such a photospheric component in the sub-MeV range for typical bursts, using simulation tools developed within the GLAST science collaboration.

  20. Simulation of Prompt Emission from GRBs with a Photospheric Component and its Detectability By GLAST

    SciTech Connect

    Battelino, Milan; Ryde, Felix; Omodei, Nicola; Longo, Francesco; /U. Trieste /INFN, Trieste

    2011-11-29

    The prompt emission from gamma-ray bursts (GRBs) still requires a physical explanation. Studies of time-resolved GRB spectra, observed in the keV-MeV range, show that a hybrid model consisting of two components, a photospheric and a non-thermal component, in many cases fits bright, single-pulsed bursts as well as, and in some instances even better than, the Band function. With an energy coverage from 8 keV up to 300 GeV, GLAST will give us an unprecedented opportunity to further investigate the nature of the prompt emission. In particular, it will give us the possibility to determine whether a photospheric component is the determining feature of the spectrum or not. Here we present a short study of the ability of GLAST to detect such a photospheric component in the sub-MeV range for typical bursts, using simulation tools developed within the GLAST science collaboration.

  1. Conceptual Design Gamma-Ray Large Area Space Telescope (GLAST) Tower Structure

    SciTech Connect

    Jennings, Chad

    2002-07-18

    The main objective of this work was to develop a conceptual design and engineering prototype for the Gamma-ray Large Area Space Telescope (GLAST) tower structure. This thesis describes the conceptual design of a GLAST tower and the fabrication and testing of a prototype tower tray. The requirements were that the structure had to support GLAST's delicate silicon strip detector array through ground handling, launch and in orbit operations as well as provide for thermal and electrical pathways. From the desired function and the given launch vehicle for the spacecraft that carries the GLAST detector, an efficient structure was designed which met the requirements. This thesis developed in three stages: design, fabrication, and testing. During the first stage, a general set of specifications was used to develop the initial design, which was then analyzed and shown to meet or exceed the requirements. The second stage called for the fabrication of prototypes to prove manufacturability and gauge cost and time estimates for the total project. The last step called for testing the prototypes to show that they performed as the analysis had shown and prove that the design met the requirements. As a spacecraft engineering exercise, this project required formulating a solution based on engineering judgment, analyzing the solution using advanced engineering techniques, then proving the validity of the design and analysis by the manufacturing and testing of prototypes. The design described here met all the requirements set out by the needs of the experiment and operating concerns. This strawman design is not intended to be the complete or final design for the GLAST instrument structure, but instead examines some of the main challenges involved and demonstrates that there are solutions to them. The purpose of these tests was to prove that there are solutions to the basic mechanical, electrical and thermal problems presented with the GLAST project.

  2. Space Shuttle Star Tracker Challenges

    NASA Technical Reports Server (NTRS)

    Herrera, Linda M.

    2010-01-01

    The space shuttle fleet of avionics was originally designed in the 1970's. Many of the subsystems have been upgraded and replaced, however some original hardware continues to fly. Not only fly, but has proven to be the best design available to perform its designated task. The shuttle star tracker system is currently flying as a mixture of old and new designs, each with a unique purpose to fill for the mission. Orbiter missions have tackled many varied missions in space over the years. As the orbiters began flying to the International Space Station (ISS), new challenges were discovered and overcome as new trusses and modules were added. For the star tracker subsystem, the growing ISS posed an unusual problem, bright light. With two star trackers on board, the 1970's vintage image dissector tube (IDT) star trackers track the ISS, while the new solid state design is used for dim star tracking. This presentation focuses on the challenges and solutions used to ensure star trackers can complete the shuttle missions successfully. Topics include KSC team and industry partner methods used to correct pressurized case failures and track system performance.

  3. Design and performance of the silicon strip tracker of the Fermi Large Area Telescope

    NASA Astrophysics Data System (ADS)

    Bregeon, J.

    2011-12-01

    The Large Area Telescope (LAT) is the primary instrument on-board the Fermi Gamma-ray Space Telescope (Fermi), an observatory on a low Earth orbit that was launched on 11 June 2008 to monitor the high energy γ-ray sky. The LAT tracker is a solid-state instrument: tungsten foils convert the gamma rays into electron-positron pairs which are then tracked in silicon planes in order to reconstruct the incoming photon direction. The tracker comprises 36 planes of single-sided silicon strip detectors, for a total of 73 square meters of silicon, read out by nearly 900,000 amplifier-discriminator channels. The system operates on only 160 W of conditioned power while achieving > 99% single-plane efficiency within its active area and better than 1 channel per million noise occupancy. We describe the tracker design and performance, and discuss in particular the excellent stability of the hardware response during the first three years of operation on orbit.

  4. The Do/ scintillating fiber tracker

    SciTech Connect

    Bross, A.; Gutierrez, G.; Grunendahl, S.; Lincoln, D.; Ramberg, E.; Ray, R.; Ruchti, R.; Warchol, J.; Wayne, M.; Choic, S.

    1998-11-01

    The Do/ detector is being upgraded in preparation for the next collider run at Fermilab. The Central Fiber Tracker discussed in this report is a major component of the Do/ upgrade. The expected Tevatron luminosity of 2{times}10{sup 32} cm{sup {minus}2} sec{sup {minus}1}, the 132ns bunch crossing time, and the Do/ detector constraints of a 2 Tesla solenoid and a 52 cm lever arm, make a scintillating fiber based tracker an optimal choice for the upgrade of the Do/ detector. {copyright} {ital 1998 American Institute of Physics.}

  5. Fermi LAT detection of Increased Flux from new gamma-ray blazar PKS 0250-225

    NASA Astrophysics Data System (ADS)

    Corbel, Stephane; Reyes, Luis C.

    2009-02-01

    The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope (formerly GLAST, launched June 11, 2008), has observed an increasing gamma-ray flux from a source positionally consistent with PKS 0250-225 (RA: 02h52m47.9s, Dec:-22d19m25s, J2000). Preliminary analysis indicates that PKS 0250-225 (z=1.427 ; as CGRaBS J0252-2219 in Healey S. et al. 2007, ApJS, 175, 97) has been in a high state since Feb 17 with a gamma-ray flux (E>100MeV) of (0.5 +/- 0.1) x 10-6 ph cm-2 s-1, which represents a > 3-fold increase in flux with respect to the average preliminary flux observed during the first 6 months of data of the Fermi mission and about an 8-fold increase with respect to the first 3 months, suggesting thus a long-term trend of increasing flux.

  6. Correlative Spectral Analysis of Gamma-Ray Bursts using Swift-BAT and GLAST-GBM

    SciTech Connect

    Stamatikos, Michael; Sakamoto, Takanori; Band, David L.

    2008-05-22

    We discuss the preliminary results of spectral analysis simulations involving anticipated correlated multi-wavelength observations of gamma-ray bursts (GRBs) using Swift's Burst Alert Telescope (BAT) and the Gamma-Ray Large Area Space Telescope's (GLAST) Burst Monitor (GLAST-GBM), resulting in joint spectral fits, including characteristic photon energy (E{sub peak}) values, for a conservative annual estimate of {approx}30 GRBs. The addition of BAT/s spectral response will (i) complement in-orbit calibration efforts of GBM's detector response matrices, (ii) augment GLAST's low energy sensitivity by increasing the {approx}20-100 keV effective area, (iii) facilitate ground-based follow-up efforts of GLAST GRBs by increasing GBM's source localization precision, and (iv) help identify a subset of non-triggered GRBs discovered via off-line GBM data analysis. Such multi-wavelength correlative analyses, which have been demonstrated by successful joint-spectral fits of Swift-BAT GRBs with other higher energy detectors such as Konus-WIND and Suzaku-WAM, would enable the study of broad-band spectral and temporal evolution of prompt GRB emission over three energy decades, thus potentially increasing science return without placing additional demands upon mission resources throughout their contemporaneous orbital tenure over the next decade.

  7. Adding the GLAST Burst Monitor to the 3rd Interplanetary Network

    SciTech Connect

    Hurley, Kevin

    2007-07-12

    The addition of the GLAST Burst Monitor to the interplanetary network is discussed. The IPN can detect about 32% of the GBM events, and reduce the sizes of their error boxes substantially. These error boxes have a wide variety of uses.

  8. Prospects for High Energy Detection of Microquasars with the AGILE and GLAST Gamma-Ray Telescopes

    SciTech Connect

    Santolamazza, Patrizia; Pittori, Carlotta; Verrecchia, Francesco

    2007-08-21

    We estimate the sensitivities of the AGILE and GLAST {gamma}-ray experiments taking into account two cases for the galactic {gamma}-ray diffuse background (at high galactic latitude and toward the galactic center). Then we use sensitivities to estimate microquasar observability with the two experiments, assuming the {gamma}-ray emission above 100 MeV of a recent microquasar model.

  9. TacNet Tracker Software

    Energy Science and Technology Software Center (ESTSC)

    2008-08-04

    The TacNet Tracker will be used for the monitoring and real-time tracking of personnel and assets in an unlimited number of specific applications. The TacNet Tracker software is a VxWorks Operating System based programming package that controls the functionality for the wearable Tracker. One main use of the TacNet Tracker is in Blue Force Tracking, the ability to track the good guys in an adversarial situation or in a force-on-force or real battle conditions. Themore » purpose of blue force tracking is to provide situational awareness to the battlefield commanders and personnel. There are practical military applications with the TacNet Tracker.The mesh network is a wireless IP communications network that moves data packets from source IP addresses to specific destination IP addresses. Addresses on the TacNet infrastructure utilize an 8-bit network mask (255.0.0.0). In other words, valid TacNet addresses range from 10.0.0.1 to 10.254.254.254. The TacNet software design uses uni-cast transmission techniques because earlier mesh network software releases did not provide for the ability to utilize multi-cast data movement. The TacNet design employs a list of addresses to move information within the TacNet infrastructure. For example, a convoy text file containing the IP addresses of all valid receivers of TacNet information could be used for transmitting the information and for limiting transmission to addresses on the list.« less

  10. TacNet Tracker Software

    SciTech Connect

    WISEMAN, JAMES; & STEVENS, JAMES

    2008-08-04

    The TacNet Tracker will be used for the monitoring and real-time tracking of personnel and assets in an unlimited number of specific applications. The TacNet Tracker software is a VxWorks Operating System based programming package that controls the functionality for the wearable Tracker. One main use of the TacNet Tracker is in Blue Force Tracking, the ability to track the good guys in an adversarial situation or in a force-on-force or real battle conditions. The purpose of blue force tracking is to provide situational awareness to the battlefield commanders and personnel. There are practical military applications with the TacNet Tracker.The mesh network is a wireless IP communications network that moves data packets from source IP addresses to specific destination IP addresses. Addresses on the TacNet infrastructure utilize an 8-bit network mask (255.0.0.0). In other words, valid TacNet addresses range from 10.0.0.1 to 10.254.254.254. The TacNet software design uses uni-cast transmission techniques because earlier mesh network software releases did not provide for the ability to utilize multi-cast data movement. The TacNet design employs a list of addresses to move information within the TacNet infrastructure. For example, a convoy text file containing the IP addresses of all valid receivers of TacNet information could be used for transmitting the information and for limiting transmission to addresses on the list.

  11. LHCb Upgrade: Scintillating Fibre Tracker

    NASA Astrophysics Data System (ADS)

    Tobin, Mark

    2016-07-01

    The LHCb detector will be upgraded during the Long Shutdown 2 (LS2) of the LHC in order to cope with higher instantaneous luminosities and to read out the data at 40 MHz using a trigger-less read-out system. All front-end electronics will be replaced and several sub-detectors must be redesigned to cope with higher occupancy. The current tracking detectors downstream of the LHCb dipole magnet will be replaced by the Scintillating Fibre (SciFi) Tracker. The SciFi Tracker will use scintillating fibres read out by Silicon Photomultipliers (SiPMs). State-of-the-art multi-channel SiPM arrays are being developed to read out the fibres and a custom ASIC will be used to digitise the signals from the SiPMs. The evolution of the design since the Technical Design Report in 2014 and the latest R & D results are presented.

  12. The LHCb Silicon Tracker Project

    NASA Astrophysics Data System (ADS)

    Agari, M.; Bauer, C.; Baumeister, D.; Blouw, J.; Hofmann, W.; Knöpfle, K. T.; Löchner, S.; Schmelling, M.; Pugatch, V.; Bay, A.; Carron, B.; Frei, R.; Jiminez-Otero, S.; Tran, M.-T.; Voss, H.; Adeva, B.; Esperante, D.; Lois, C.; Vasquez, P.; Bernhard, R. P.; Bernet, R.; Ermoline, Y.; Gassner, J.; Köstner, S.; Lehner, F.; Needham, M.; Siegler, M.; Steinkamp, O.; Straumann, U.; Vollhardt, A.; Volyanskyy, D.

    2006-01-01

    Two silicon strip detectors, the Trigger Tracker(TT) and the Inner Tracker(IT) will be constructed for the LHCb experiment. Transverse momentum information extracted from the TT will be used in the Level 1 trigger. The IT is part of the main tracking system behind the magnet. Both silicon detectors will be read out using a custom-developed chip by the ASIC lab in Heidelberg. The signal-over-noise behavior and performance of various geometrical designs of the silicon sensors, in conjunction with the Beetle read-out chip, have been extensively studied in test beam experiments. Results from those experiments are presented, and have been used in the final choice of sensor geometry.

  13. Star-Tracker Computer Program

    NASA Technical Reports Server (NTRS)

    Glavich, Thomas

    1987-01-01

    Image-analyzing pointing systems aimed to high precision. Star-tracker program, STRACKER, developed to solve algorithm-design problems for area-array tracking and pointing systems operating at accuracies of 0.001 to 0.01 picture element. Includes auxiliary programs for reformatting point-spread data from commercial ACCOSV lens-design program. Other optical-analysis program data reformatted by use of utility routines included in package. Written in FORTRAN 77.

  14. Introduction to Mini Muon Tracker

    SciTech Connect

    Borozdin, Konstantin N.

    2012-08-13

    Using a mini muon tracker developed at the Los Alamos National Laboratory we performed experiments of simple landscapes of various materials, including TNT, 9501, lead, tungsten, aluminium, and water. Most common scenes are four two inches thick step wedges of different dimensions: 12-inch x 12-inch, 12-inch x 9-inch, 12-inch x 6-inch, and 12-inch x 3-inch; and a one three inches thick hemisphere of lead with spherical hollow, and a similar full lead sphere.

  15. The CMS tracker control system

    NASA Astrophysics Data System (ADS)

    Dierlamm, A.; Dirkes, G. H.; Fahrer, M.; Frey, M.; Hartmann, F.; Masetti, L.; Militaru, O.; Shah, S. Y.; Stringer, R.; Tsirou, A.

    2008-07-01

    The Tracker Control System (TCS) is a distributed control software to operate about 2000 power supplies for the silicon modules of the CMS Tracker and monitor its environmental sensors. TCS must thus be able to handle about 104 power supply parameters, about 103 environmental probes from the Programmable Logic Controllers of the Tracker Safety System (TSS), about 105 parameters read via DAQ from the DCUs in all front end hybrids and from CCUs in all control groups. TCS is built on top of an industrial SCADA program (PVSS) extended with a framework developed at CERN (JCOP) and used by all LHC experiments. The logical partitioning of the detector is reflected in the hierarchical structure of the TCS, where commands move down to the individual hardware devices, while states are reported up to the root which is interfaced to the broader CMS control system. The system computes and continuously monitors the mean and maximum values of critical parameters and updates the percentage of currently operating hardware. Automatic procedures switch off selected parts of the detector using detailed granularity and avoiding widespread TSS intervention.

  16. Upgrade of the CMS tracker

    NASA Astrophysics Data System (ADS)

    Tricomi, A.

    2014-03-01

    The LHC machine is planning an upgrade program which will smoothly bring the luminosity up to or above 5 × 1034 cm-2s-1 sometimes after 2020, to possibly reach an integrated luminosity of 3000 fb-1 at the end of that decade. The foreseen increases of both the instantaneous and the integrated luminosity by the LHC during the next ten years will necessitate a stepwise upgrade of the CMS tracking detector. During the extended end-of-year shutdown 2016-2017 the pixel detector will be exchanged with a new one. The so-called Phase1 Pixel foresees one additional barrel layer and one additional end-cap disk, a new readout chip, reduction of material, and the installation of more efficient cooling and powering systems. In the so-called Phase2, when LHC will reach the High Luminosity (HL-LHC) phase, CMS will need a completely new Tracker detector, in order to fully exploit the high-demanding operating conditions and the delivered luminosity. The new Tracker should have also trigger capabilities. To achieve such goals, R&D activities are ongoing to explore options and develop solutions that would allow including tracking information at Level-1. The design choices for the CMS pixel and outer tracker upgrades are discussed along with some highlights of the R&D activities.

  17. Activity trackers: a critical review.

    PubMed

    Lee, Jeon; Finkelstein, Joseph

    2014-01-01

    The wearable consumer health devices can be mainly divided into activity trackers, sleep trackers, and stress management devices. These devices are widely advertised to provide positive effects on the user's daily behaviours and overall heath. However, objective evidence supporting these claims appears to be missing. The goal of this study was to review available evidence pertaining to performance of activity trackers. A comprehensive review of available information has been conducted for seven representative devices and the validity of marketing claims was assessed. The device assessment was based on availability of verified output metrics, theoretical frameworks, systematic evaluation, and FDA clearance. The review identified critical absence of supporting evidence of advertised functions and benefits for the majority of the devices. Six out of seven devices did not provide any information on sensor accuracy and output validity at all. Possible underestimation or overestimation of specific health indicators reported to consumers was not clearly disclosed to the public. Furthermore, significant limitations of these devices which can be categorized into user restrictions, user responsibilities and company disclaimers could not be easily found or comprehended by unsophisticated users and may represent a serious health hazard. PMID:25160247

  18. Fermi-LAT Observations of Galactic Transients

    NASA Technical Reports Server (NTRS)

    Hays, Elizabeth

    2011-01-01

    This slide presentation reviews the observations of Galactic transients by the Large Area Telescope (LAT) on the Fermi Gamma Ray Space Telescope. The LAT is producing spectacular results for the GeV transient sky, some of which are shown and reviewed. Some of the results in the GeV range that are discussed in this presentation are: (1) New blazars and unidentified transients (2) the jet of the Cygnus X-3 microquasar (3) gamma rays from V407 Cygni nova (4) Fast high-energy gamma-ray flares from the Crab Nebula

  19. FGF2 alleviates PTSD symptoms in rats by restoring GLAST function in astrocytes via the JAK/STAT pathway.

    PubMed

    Feng, Dayun; Guo, Baolin; Liu, Gaohua; Wang, Bao; Wang, Wen; Gao, Guodong; Qin, Huaizhou; Wu, Shengxi

    2015-08-01

    In our previous study, we demonstrated that fibroblast growth factor 2 (FGF2) administration alleviated posttraumatic stress disorder (PTSD) symptoms via an "astrocyte-related" mechanism. We further investigated the changes in the astrocytic glutamate transporters GLAST and GLT-1 and in JAK/STAT3 signaling (which is involved in astrocyte activation and GLAST/GLT-1 function) in single prolonged stress (SPS) model rats. High-performance liquid chromatography (HPLC), Western blot and immunohistochemistry analyses revealed a significant SPS-induced increase in the concentration of glutamate in the cerebrospinal fluid and decrease in GLAST/GLT-1 expression and JAK/STAT3 signaling. Treatment with FGF2 significantly alleviated GLAST/GLT-1 dysfunction, JAK/STAT3 signaling inhibition, and the behavioral abnormalities. The administration of the JAK/STAT pathway inhibitor AG490 blocked the effects of FGF2 on PTSD symptoms, astrocyte activation, and GLAST, but not GLT-1, expression in vivo and in vitro. Our findings suggest that astrocytic JAK/STAT signaling is associated with SPS-induced GLAST dysfunction and that FGF2 protects against PTSD symptoms by restoring astrocytic glutamate uptake via the JAK/STAT signaling pathway. PMID:25979764

  20. Gamma-telescopes Fermi/LAT and GAMMA-400 Trigger Systems Event Recognizing Methods Comparison

    NASA Astrophysics Data System (ADS)

    Arkhangelskaja, I. V.; Murchenko, A. E.; Chasovikov, E. N.; Arkhangelskiy, A. I.; Kheymits, M. D.

    Usually instruments for high-energy γ-quanta registration consists of converter (where γ-quanta produced pairs) and calorimeter for particles energy measurements surrounded by anticoincidence shield used to events identification (whether incident particle was charged or neutral). The influence of pair formation by γ-quanta in shield and the backsplash (moved in the opposite direction particles created due high energy γ-rays interact with calorimeter) should be taken into account. It leads to decrease both effective area and registration efficiency at E>10 GeV. In the presented article the event recognizing methods used in Fermi/LAT trigger system is considered in comparison with the ones applied in counting and triggers signals formation system of gamma-telescope GAMMA-400. The GAMMA-400 (Gamma Astronomical Multifunctional Modular Apparatus) will be the new high-apogee space γ-observatory. The GAMMA-400 consist of converter-tracker based on silicon-strip coordinate detectors interleaved with tungsten foils, imaging calorimeter make of 2 layers of double (x, y) silicon strip coordinate detectors interleaved with planes of CsI(Tl) crystals and the electromagnetic calorimeter CC2 consists only of CsI(Tl) crystals. Several plastics detections systems used as anticoincidence shield, for particles energy and moving direction estimations. The main differences of GAMMA-400 constructions from Fermi/LAT one are using the time-of-flight system with base of 50 cm and double layer structure of plastic detectors provides more effective particles direction definition and backsplash rejection. Also two calorimeters in GAMMA-400 composed the total absorbtion spectrometer with total thickness ∼ 25 X0 or ∼1.2 λ0 for vertical incident particles registration and 54 X0 or 2.5 λ0 for laterally incident ones (where λ0 is nuclear interaction length). It provides energy resolution 1-2% for 10 GeV-3.0×103 GeV events while the Fermi/LAT energy resolution does not reach such a

  1. LATS2 Positively Regulates Polycomb Repressive Complex 2

    PubMed Central

    Torigata, Kosuke; Daisuke, Okuzaki; Mukai, Satomi; Hatanaka, Akira; Ohka, Fumiharu; Motooka, Daisuke; Nakamura, Shota; Ohkawa, Yasuyuki; Yabuta, Norikazu; Kondo, Yutaka; Nojima, Hiroshi

    2016-01-01

    LATS2, a pivotal Ser/Thr kinase of the Hippo pathway, plays important roles in many biological processes. LATS2 also function in Hippo-independent pathway, including mitosis, DNA damage response and epithelial to mesenchymal transition. However, the physiological relevance and molecular basis of these LATS2 functions remain obscure. To understand novel functions of LATS2, we constructed a LATS2 knockout HeLa-S3 cell line using TAL-effector nuclease (TALEN). Integrated omics profiling of this cell line revealed that LATS2 knockout caused genome-wide downregulation of Polycomb repressive complex 2 (PRC2) and H3K27me3. Cell-cycle analysis revealed that downregulation of PRC2 was not due to cell cycle aberrations caused by LATS2 knockout. Not LATS1, a homolog of LATS2, but LATS2 bound PRC2 on chromatin and phosphorylated it. LATS2 positively regulates histone methyltransferase activity of PRC2 and their expression at both the mRNA and protein levels. Our findings reveal a novel signal upstream of PRC2, and provide insight into the crucial role of LATS2 in coordinating the epigenome through regulation of PRC2. PMID:27434182

  2. LATS2 Positively Regulates Polycomb Repressive Complex 2.

    PubMed

    Torigata, Kosuke; Daisuke, Okuzaki; Mukai, Satomi; Hatanaka, Akira; Ohka, Fumiharu; Motooka, Daisuke; Nakamura, Shota; Ohkawa, Yasuyuki; Yabuta, Norikazu; Kondo, Yutaka; Nojima, Hiroshi

    2016-01-01

    LATS2, a pivotal Ser/Thr kinase of the Hippo pathway, plays important roles in many biological processes. LATS2 also function in Hippo-independent pathway, including mitosis, DNA damage response and epithelial to mesenchymal transition. However, the physiological relevance and molecular basis of these LATS2 functions remain obscure. To understand novel functions of LATS2, we constructed a LATS2 knockout HeLa-S3 cell line using TAL-effector nuclease (TALEN). Integrated omics profiling of this cell line revealed that LATS2 knockout caused genome-wide downregulation of Polycomb repressive complex 2 (PRC2) and H3K27me3. Cell-cycle analysis revealed that downregulation of PRC2 was not due to cell cycle aberrations caused by LATS2 knockout. Not LATS1, a homolog of LATS2, but LATS2 bound PRC2 on chromatin and phosphorylated it. LATS2 positively regulates histone methyltransferase activity of PRC2 and their expression at both the mRNA and protein levels. Our findings reveal a novel signal upstream of PRC2, and provide insight into the crucial role of LATS2 in coordinating the epigenome through regulation of PRC2. PMID:27434182

  3. LAT Automated Science Processing for Gamma-Ray Bursts

    SciTech Connect

    Chiang, James

    2007-05-01

    The LAT Instrument Science Operations Center (ISOC) will perform various tasks to support coordination of multiwavelength observations for transient sources. In this paper, we describe the prototype implementation of the Automated Science Processing (ASP) for the detection and analysis of gamma-ray bursts (GRBs) in LAT and GBM data. The GRB-related tasks include: position refinement using LAT data given initial GBM or GCN locations, spectral analysis using LAT data alone, joint spectral fitting with GBM data, gamma-ray afterglow detection and characterization, and blind searches for prompt burst emission in LAT data.

  4. Studying the High Energy Gamma Ray Sky with Gamma Ray Large Area Space Telescope (GLAST)

    NASA Technical Reports Server (NTRS)

    Kamae, T.; Ohsugi, T.; Thompson, D. J.; Watanabe, K.

    1998-01-01

    Building on the success of the Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory, the Gamma Ray Large Area Space Telescope (GLAST) will make a major step in the study of such subjects as blazars, gamma Ray bursts, the search for dark matter, supernova remnants, pulsars, diffuse radiation, and unidentified high energy sources. The instrument will be built on new and mature detector technologies such as silicon strip detectors, low-power low-noise LSI, and a multilevel data acquisition system. GLAST is in the research and development phase, and one full tower (of 25 total) is now being built in collaborating institutes. The prototype tower will be tested thoroughly at Stanford Linear Accelerator Center (SLAC) in the fall of 1999.

  5. The h1 Silicon Tracker

    NASA Astrophysics Data System (ADS)

    List, Benno

    2004-07-01

    The silicon tracker of the H1 experiment at HERA consists of a barrel part and two endcaps with disks. The barrel part has 2 layers of double sided strip sensors with 81920 readout channels. The forward part uses 7 wheels of single sided strip detectors that measure three coordinates (r, u, and v) with 92160 channels. The backward part uses single sided strip detectors in 6 wheels, measuring the u and v coordinates with 84480 channels. These wheels are intersprsed with 4 wheels of pad detectors that provide fast triggering signals.

  6. The CDF silicon vertex tracker

    SciTech Connect

    A. Cerri et al.

    2000-10-10

    Real time pattern recognition is becoming a key issue in many position sensitive detector applications. The CDF collaboration is building SVT: a specialized electronic device designed to perform real time track reconstruction using the silicon vertex detector (SVX II). This will strongly improve the CDF capability of triggering on events containing b quarks, usually characterized by the presence of a secondary vertex. SVT is designed to reconstruct in real time charged particles trajectories using data coming from the Silicon Vertex detector and the Central Outer Tracker drift chamber. The SVT architecture and algorithm have been specially tuned to minimize processing time without degrading parameter resolution.

  7. Optical filtering for star trackers

    NASA Technical Reports Server (NTRS)

    Wilson, R. E.

    1973-01-01

    The optimization of optical filtering was investigated for tracking faint stars, down to the fifth magnitude. The effective wavelength and bandwidth for tracking pre-selected guide stars are discussed along with the results of an all-electronic tracker with a star tracking photomultiplier, which was tested with a simulated second magnitude star. Tables which give the sum of zodiacal light and galactic background light over the entire sky for intervals of five degrees in declination, and twenty minutes in right ascension are included.

  8. Understanding The GLAST Burst Monitor Detector Calibration: A Detailed Simulation Of The Calibration Including The Environment

    SciTech Connect

    Steinle, Helmut; Kienlin, Andreas von; Bissaldi, Elisabetta; Lichti, Giselher; Diehl, Roland; Greiner, Jochen; Meegan, Charles A.; Fishman, Gerald J.; Kouveliotou, Chryssa; Wilson-Hodge, Colleen A.; Kippen, R. Marc; Hoover, Andrew S.

    2007-07-12

    The GLAST Burst Monitor (GBM) is the secondary instrument on NASA's next Gamma-ray mission GLAST. It will enhance the capabilities of GLAST by locating and detecting cosmic gamma-ray bursts at lower energies by the use of 12 NaI detectors (energy range 10 keV to 1 MeV) and 2 BGO-detectors (energy range 150 keV to 30 MeV). GBM was built in a close collaboration between the MPE and the Marshall Space Flight Center (MSFC). The angular and energy response of each GBM detector has been calibrated using various radioactive sources at different incidence angles relative to the detector in a laboratory environment at the MPE in 2005. To facilitate the understanding of the reconstruction of the detector response, a detailed simulation of the whole laboratory environment and the setup of the calibration source were performed. A modified version of the CERN GEANT 4 simulation software (provided by collaborators at the Los Alamos National Laboratory) was used.

  9. Downregulation of glutamine synthetase via GLAST suppression induces retinal axonal swelling in a rat ex vivo hydrostatic pressure model.

    PubMed

    Ishikawa, Makoto; Yoshitomi, Takeshi; Zorumski, Charles F; Izumi, Yukitoshi

    2011-08-01

    PURPOSE. High levels of glutamate can be toxic to retinal GCs. Thus, effective buffering of extracellular glutamate is important in preserving retinal structure and function. GLAST, a major glutamate transporter in the retina, and glutamine synthetase (GS) regulate extracellular glutamate accumulation and prevent excitotoxicity. This study was an examination of changes in function and expression of GLAST and GS in ex vivo rat retinas exposed to acute increases in ambient pressure. METHODS. Ex vivo rat retinas were exposed to elevated hydrostatic pressure for 24 hours. The expression of GLAST and GS were examined using immunochemistry and real-time PCR analysis. Also examined were the effects of (2S,3S)-3-[3-[4-(trifluoromethyl) benzoylamino] benzyloxy] aspartate (TFB-TBOA), an inhibitor of glutamate transporters, and l-methionine-S-sulfoximine (MSO), an inhibitor of GS. RESULTS. In this acute model, Western blot and real-time RT-PCR analyses revealed that substantially (75 mm Hg), but not moderately (35 mm Hg), elevated pressure depressed GLAST expression, diminished GS activity, and induced axonal swelling between the GC layer and the inner limiting membrane. However, at the moderately elevated pressure (35 mm Hg), administration of either TFB-TBOA or MSO also induced axonal swelling and excitotoxic neuronal damage. MSO did not depress GLAST expression but TFB-TBOA significantly suppressed GS, suggesting that downregulation of GS during pressure loading may result from impaired GLAST expression. CONCLUSIONS. The retina is at risk during acute intraocular pressure elevation due to downregulation of GS activity resulting from depressed GLAST expression. PMID:21775659

  10. Star tracker for the Apollo telescope mount

    NASA Technical Reports Server (NTRS)

    Lee, C. E.

    1971-01-01

    The star tracker for the Apollo Telescope Mount (ATM) has been designed specifically to meet the requirements of the Skylab vehicle and mission. The functions of the star tracker are presented, as well as descriptions of the optical-mechanical assembly (OMA) and the star tracker electronics (STE). Also included are the electronic and mechanical specifications, interface and operational requirements, support equipment and test requirements, and occultation information. Laboratory functional tests, environmental qualification tests, and life tests have provided a high confidence factor in the performance of the star tracker in the laboratory and on the Skylab mission.

  11. Teaching optical phenomena with Tracker

    NASA Astrophysics Data System (ADS)

    Rodrigues, M.; Simeão Carvalho, P.

    2014-11-01

    Since the invention and dissemination of domestic laser pointers, observing optical phenomena is a relatively easy task. Any student can buy a laser and experience at home, in a qualitative way, the reflection, refraction and even diffraction phenomena of light. However, quantitative experiments need instruments of high precision that have a relatively complex setup. Fortunately, nowadays it is possible to analyse optical phenomena in a simple and quantitative way using the freeware video analysis software ‘Tracker’. In this paper, we show the advantages of video-based experimental activities for teaching concepts in optics. We intend to show: (a) how easy the study of such phenomena can be, even at home, because only simple materials are needed, and Tracker provides the necessary measuring instruments; and (b) how we can use Tracker to improve students’ understanding of some optical concepts. We give examples using video modelling to study the laws of reflection, Snell’s laws, focal distances in lenses and mirrors, and diffraction phenomena, which we hope will motivate teachers to implement it in their own classes and schools.

  12. The STAR Heavy Flavor Tracker

    NASA Astrophysics Data System (ADS)

    Videbaek, Flemming; STAR Collaboration

    2013-10-01

    The Heavy Flavor Tracker (HFT) is an on-going upgrade for the STAR detector at RHIC that aim to study heavy quark production. In relativistic heavy-ion collisions at RHIC, heavy quarks are primarily created from initial hard scatterings. Since their large masses are not easily affected by the strong interaction with QCD medium they may carry information from the system at early stage. The interaction between heavy quarks and the medium is sensitive to the medium dynamics; therefore heavy quarks are suggested as an ideal probe to quantify the properties of the strongly interacting QCD matter. The HFT detectors will study this via the topological reconstruction of open charm hadrons. The HFT that consists of a thin two layer inner Pixel vertex detector, and two outer concentric layers of silicon, the Silicon Strip Detector, and the Intermediate Silicon Tracker. We will show how this detector system can assess heavy flavor physics with great precision. An overview of the HFT that will be completed for the upcoming RHIC run-14, its expected performance, and current status will be presented. Supported by the Division of Nuclear Physics of the Office of Science of the U.S. Department of Energy.

  13. GLAST Deficiency in Mice Exacerbates Gap Detection Deficits in a Model of Salicylate-Induced Tinnitus

    PubMed Central

    Yu, Hong; Vikhe Patil, Kim; Han, Chul; Fabella, Brian; Canlon, Barbara; Someya, Shinichi; Cederroth, Christopher R.

    2016-01-01

    Gap detection or gap pre-pulse inhibition of the acoustic startle (GPIAS) has been successfully used in rat and guinea pig models of tinnitus, yet this system has been proven to have low efficacy in CBA mice, with low basal GPIAS and subtle tinnitus-like effects. Here, we tested five mouse strains (CBA, BalbC, CD-1, C57BL/6 and 129sv) for pre-pulse inhibition (PPI) and gap detection with varying interstimulus intervals (ISI) and found that mice from a CBA genetic background had the poorest capacities of suppressing the startle response in the presence of a pre-pulse or a gap. CD-1 mice displayed variable responses throughout all ISI. Interestingly, C57BL/6, 129sv and BalbC showed efficient suppression with either pre-pulses or gaps with shorter ISI. The glutamate aspartate transporter (GLAST) is expressed in support cells from the cochlea and buffers the excess of glutamate. We hypothesized that loss of GLAST function could sensitize the ear to tinnitus-inducing agents, such as salicylate. Using shorter ISI to obtain a greater dynamic range to assess tinnitus-like effects, we found that disruption of gap detection by salicylate was exacerbated across various intensities of a 32-kHz narrow band noise gap carrier in GLAST knockout (KO) mice when compared to their wild-type (WT) littermates. Auditory brainstem responses (ABR) and distortion-product otoacoustic emission (DPOAE) were performed to evaluate the effects on hearing functions. Salicylate caused greater auditory threshold shifts (near 15 dB) in GLAST KO mice than in WT mice across all tested frequencies, despite similarly reduced DPOAE. Despite these changes, inhibition using broad-band gap carriers and 32 kHz pre-pulses were not affected. Our study suggests that GLAST deficiency could become a useful experimental model to decipher the mechanisms underlying drug-induced tinnitus. Future studies addressing the neurological correlates of tinnitus in this model could provide additional insights into the

  14. GLAST Deficiency in Mice Exacerbates Gap Detection Deficits in a Model of Salicylate-Induced Tinnitus.

    PubMed

    Yu, Hong; Vikhe Patil, Kim; Han, Chul; Fabella, Brian; Canlon, Barbara; Someya, Shinichi; Cederroth, Christopher R

    2016-01-01

    Gap detection or gap pre-pulse inhibition of the acoustic startle (GPIAS) has been successfully used in rat and guinea pig models of tinnitus, yet this system has been proven to have low efficacy in CBA mice, with low basal GPIAS and subtle tinnitus-like effects. Here, we tested five mouse strains (CBA, BalbC, CD-1, C57BL/6 and 129sv) for pre-pulse inhibition (PPI) and gap detection with varying interstimulus intervals (ISI) and found that mice from a CBA genetic background had the poorest capacities of suppressing the startle response in the presence of a pre-pulse or a gap. CD-1 mice displayed variable responses throughout all ISI. Interestingly, C57BL/6, 129sv and BalbC showed efficient suppression with either pre-pulses or gaps with shorter ISI. The glutamate aspartate transporter (GLAST) is expressed in support cells from the cochlea and buffers the excess of glutamate. We hypothesized that loss of GLAST function could sensitize the ear to tinnitus-inducing agents, such as salicylate. Using shorter ISI to obtain a greater dynamic range to assess tinnitus-like effects, we found that disruption of gap detection by salicylate was exacerbated across various intensities of a 32-kHz narrow band noise gap carrier in GLAST knockout (KO) mice when compared to their wild-type (WT) littermates. Auditory brainstem responses (ABR) and distortion-product otoacoustic emission (DPOAE) were performed to evaluate the effects on hearing functions. Salicylate caused greater auditory threshold shifts (near 15 dB) in GLAST KO mice than in WT mice across all tested frequencies, despite similarly reduced DPOAE. Despite these changes, inhibition using broad-band gap carriers and 32 kHz pre-pulses were not affected. Our study suggests that GLAST deficiency could become a useful experimental model to decipher the mechanisms underlying drug-induced tinnitus. Future studies addressing the neurological correlates of tinnitus in this model could provide additional insights into the

  15. Flight experience of 329K star tracker

    NASA Astrophysics Data System (ADS)

    Kruzhilov, Ivan S.; Kuniaev, Vladimir V.; Fedoseev, Victor I.; Titov, Gennadiy P.; Shevlyakov, Oleg V.; Latyncev, Sergey V.

    2013-10-01

    The paper is devoted to the results of the star tracker 329K flight tests on board of the satellites Luch-5A and Luch-5B launched into geostationary orbit in December 2011 and November 2012 respectively. Emphasis is placed on accuracy and photometric characteristics of the star tracker 329K.

  16. A Rollercoaster Viewed through Motion Tracker Data

    ERIC Educational Resources Information Center

    Pendrill, Ann-Marie; Rodjegard, Henrik

    2005-01-01

    A motion tracker measures acceleration and rotation in three dimensions, sufficient for a complete determination of the motion. In this article, a rollercoaster ride is analysed with reference to motion tracker data. The use of this type of data in education is discussed as a way to deepen students' understanding of concepts related to force and…

  17. The Chesapeake Laser Tracker in Industrial Metrology

    SciTech Connect

    Ruland, Robert E.; /SLAC

    2005-08-16

    In the summer of 1992, the survey and alignment team at the Stanford Linear Accelerator Center acquired a CMS3000 laser tracker manufactured by Chesapeake Laser Systems in Lanham, Maryland. This paper gives a description of the principles of operation and calibration of the tracker. Several applications are explained and the results shared.

  18. Ruby on Rails Issue Tracker

    NASA Technical Reports Server (NTRS)

    Rodriguez, Juan Jared

    2014-01-01

    The purpose of this report is to detail the tasks accomplished as a NASA NIFS intern for the summer 2014 session. This internship opportunity is to develop an issue tracker Ruby on Rails web application to improve the communication of developmental anomalies between the Support Software Computer Software Configuration Item (CSCI) teams, System Build and Information Architecture. As many may know software development is an arduous, time consuming, collaborative effort. It involves nearly as much work designing, planning, collaborating, discussing, and resolving issues as effort expended in actual development. This internship opportunity was put in place to help alleviate the amount of time spent discussing issues such as bugs, missing tests, new requirements, and usability concerns that arise during development and throughout the life cycle of software applications once in production.

  19. Silicon photomultipliers for scintillating trackers

    NASA Astrophysics Data System (ADS)

    Rabaioli, S.; Berra, A.; Bolognini, D.; Bonvicini, V.; Bosisio, L.; Ciano, S.; Iugovaz, D.; Lietti, D.; Penzo, A.; Prest, M.; Rashevskaya, I.; Reia, S.; Stoppani, L.; Vallazza, E.

    2012-12-01

    In recent years, silicon photomultipliers (SiPMs) have been proposed as a new kind of readout device for scintillating detectors in many experiments. A SiPM consists of a matrix of parallel-connected pixels, which are independent photon counters working in Geiger mode with very high gain (∼106). This contribution presents the use of an array of eight SiPMs (manufactured by FBK-irst) for the readout of a scintillating bar tracker (a small size prototype of the Electron Muon Ranger detector for the MICE experiment). The performances of the SiPMs in terms of signal to noise ratio, efficiency and time resolution will be compared to the ones of a multi-anode photomultiplier tube (MAPMT) connected to the same bars. Both the SiPMs and the MAPMT are interfaced to a VME system through a 64 channel MAROC ASIC.

  20. ST - SCHEDULE TRACKER COMPUTER PROGRAM

    NASA Technical Reports Server (NTRS)

    Collazo, F. F.

    1994-01-01

    The Schedule Organizer, SO (COSMIC Program MSC-21525), Schedule Tracker, ST, and Schedule Report Generator, SRG (COSMIC Program MSC-21527), are programs that manipulate data base files in ways that are advantageous to scheduling applications. Originally designed for the Space Shuttle flight schedule, the program can be easily modified for other scheduling situations. Schedule Organizer provides a simple method for generating distribution lists. These distribution lists contain readers' names for each task schedule defined by the input files. Schedule Tracker provides an effective method for tracking tasks that are 'past due' and/or 'near term'. ST generates reports for each responsible staff member with one or more assigned tasks that fall within the two listed categories. This enables an engineering manager to monitor tasks assigned to staff by running ST on a weekly basis. ST only lists tasks on reports that have become past due or are scheduled for recent completion (near term). Schedule Report Generator provides a simple method for generating periodic schedule reports. ST and SRG use the same data base file as input. The common data base file has a maximum number of 400 entries. The time span of all three programs is nineteen months. Both of these maximum numbers can be modified by the user. ST requires the VMS Operating System on DEC VAX and was written in PL/1 and DEC Command Language (DCL). The program requires a memory of 233KB. ST can be purchased separately or in a package (COSMIC Program COS-10021) containing SO, ST, and SRG. ST was developed in 1985.

  1. Overexpression of L-Type Amino Acid Transporter 1 (LAT1) and 2 (LAT2): Novel Markers of Neuroendocrine Tumors

    PubMed Central

    Barollo, Susi; Bertazza, Loris; Watutantrige-Fernando, Sara; Censi, Simona; Cavedon, Elisabetta; Galuppini, Francesca; Pennelli, Gianmaria; Fassina, Ambrogio; Citton, Marilisa; Rubin, Beatrice; Pezzani, Raffaele; Benna, Clara; Opocher, Giuseppe; Iacobone, Maurizio; Mian, Caterina

    2016-01-01

    Background 6-18F-fluoro-L-3,4-dihydroxyphenylalanine (18F-FDOPA) PET is a useful tool in the clinical management of pheochromocytoma (PHEO) and medullary thyroid carcinoma (MTC). 18F-FDOPA is a large neutral amino acid biochemically resembling endogenous L-DOPA and taken up by the L-type amino acid transporters (LAT1 and LAT2). This study was conducted to examine the expression of the LAT system in PHEO and MTC. Methods Real-time PCR and Western blot analyses were used to assess LAT1 and LAT2 gene and protein expression in 32 PHEO, 38 MTC, 16 normal adrenal medulla and 15 normal thyroid tissue samples. Immunohistochemistry method was applied to identify the proteins’ subcellular localization. Results LAT1 and LAT2 were overexpressed in both PHEO and MTC by comparison with normal tissues. LAT1 presented a stronger induction than LAT2, and their greater expression was more evident in PHEO (15.1- and 4.1-fold increases, respectively) than in MTC (9.9- and 4.1-fold increases, respectively). Furthermore we found a good correlation between LAT1/2 and GLUT1 expression levels. A positive correlation was also found between urinary noradrenaline and adrenaline levels and LAT1 gene expression in PHEO. The increased expression of LAT1 is also confirmed at the protein level, in both PHEO and MTC, with a strong cytoplasmic localization. Conclusions The present study is the first to provide experimental evidence of the overexpression in some NET cancers (such as PHEO or MTC) of L-type amino acid transporters, and the LAT1 isoform in particular, giving the molecular basis to explain the increase of the DOPA uptake seen in such tumor cells. PMID:27224648

  2. Membrane topology of the high-affinity L-glutamate transporter (GLAST- 1) of the central nervous system

    PubMed Central

    1996-01-01

    The membrane topology of the high affinity, Na(+)-coupled L-glutamate/L- aspartate transporter (GLAST-1) of the central nervous system has been determined. Truncated GLAST-1 cDNA constructs encoding protein fragments with an increasing number of hydrophobic regions were fused to a cDNA encoding a reporter peptide with two N-glycosylation sites. The respective cRNA chimeras were translated in vitro and in vivo in Xenopus oocytes. Posttranslational N-glycosylation of the two reporter consensus sites monitors the number, size, and orientation of membrane- spanning domains. The results of our experiments suggest a novel 10- transmembrane domain topology of GLAST-1, a representative of the L- glutamate neurotransmitter transporter family, with its NH2 and COOH termini on the cytoplasmic side, six NH2-terminal hydrophobic transmembrane alpha-helices, and four COOH-terminal short hydrophobic domains spanning the bilayer predicted as beta-sheets. PMID:8991097

  3. LAT1 regulates growth of uterine leiomyoma smooth muscle cells.

    PubMed

    Xia Luo; Coon, John S; Su, Emily; Pearson, Elizabeth Kerry; Ping Yin; Ishikawa, Hiroshi; Bulun, Serdar E

    2010-09-01

    L-type amino acid transporter 1 (LAT1) and LAT2 were shown to encode system L, which mediates the Na(+)-independent transport of branched-chain and aromatic amino acids. We demonstrated previously that LAT2 is a progesterone receptor target gene involved in leiomyoma growth. The role of LAT1 in the regulation of human uterine leiomyoma growth, however, remains unelucidated. We herein investigated the function of LAT1 and its progesterone-mediated regulation within human uterine leiomyoma smooth muscle (LSM) cells (n = 8) and tissues (n = 29). In vivo, LAT1 expression was higher in leiomyoma than in myometrial tissue. LAT1 knockdown augmented cell proliferation and viability. Treatment of LSM cells with RU486 markedly increased LAT1 messenger RNA (mRNA) levels but decreased proliferation in a dose-dependent manner. L-type amino acid transporter 1 as a downstream target, however, did not entirely account for this antiproliferative effect of RU486 on LSM cells. Taken together, LAT1 may have a critical and complex role in regulating human leiomyoma cell growth. PMID:20601542

  4. The D0 silicon microstrip tracker

    NASA Astrophysics Data System (ADS)

    Quinn, Breese; D0 Collaboration

    2003-03-01

    The D0 collaboration has completed building a 793,000 channel silicon microstrip tracker for the D0 upgrade. The tracker consists of 768 ladder and wedge assemblies including both single- and double-sided detectors. Detector readout utilizes the SVX-IIE radiation hard chip with on-chip digitization and sparsification. A brief review of the detector design is presented along with results from the assembly and testing processes. The operation of the full readout chain and the performance of the silicon tracker are described. Finally, lessons for future production of large scale tracking systems are discussed.

  5. Personal Activity Trackers and the Quantified Self.

    PubMed

    Hoy, Matthew B

    2016-01-01

    Personal activity trackers are an inexpensive and easy way for people to record their physical activity and simple biometric data. As these devices have increased in availability and sophistication, their use in daily life and in medicine has grown. This column will briefly explore what these devices are, what types of data they can track, and how that data can be used. It will also discuss potential problems with trackers and how librarians can help patients and physicians manage and protect activity data. A brief list of currently available activity trackers is also included. PMID:26794199

  6. Science of Compact X- and Gamma-ray Sources: MAXI and GLAST

    NASA Technical Reports Server (NTRS)

    Thompson, Dave

    2008-01-01

    MAXI and GLAST will be surveying the sky simultaneously. Compact objects that may show variability will be excellent targets for coordinated multiwavelength studies. Gamma-ray bursts (and afterglows), pulsars, high-mass X-ray binaries, microquasars, and active galactic nuclei are all objects whose X- and gamma-ray relationship can be explored by such observations. Of particular interest will be variable unidentified gamma-ray sources, whose contemporaneous observations by MAXI may prove decisive in identifying the source of the high-energy emission.

  7. Simulating the High Energy Gamma-Ray Sky Seen by the GLAST Large Area Telescope

    NASA Astrophysics Data System (ADS)

    Longo, F.; Azzi, P.; Bastieri, D.; Busetto, P.; Lei, Y.; Rando, R.; Tibolla, O.; Baldini, L.; Kuss, M.; Latronico, L.; Omodei, N.; Razzano, M.; Spandre, G.; Boinee, P.; de Angelis, A.; Frailis, M.; Brigida, M.; Gargano, F.; Giglietto, N.; Loparco, F.; Mazziotta, M. N.; Cecchi, C.; Lubrano, P.; Marcucci, F.; Pepe, M.; Tosti, G.; Lionetto, A.; Morselli, A.; Pittori, C.

    This paper presents the simulation of the GLAST high energy gamma-ray telescope. The simulation package, written in C++, is based on the Geant4 toolkit, and it is integrated into a general framework used to process events. A detailed simulation of the electronic signals inside Silicon detectors has been provided and it is used for the particle tracking, which is handled by a dedicated software. A unique repository for the geometrical description of the detector has been realized using the XML language and a C++ library to access this information has been designed and implemented. A new event display based on the HepRep protocol was implemented.

  8. Pulsars at the Highest Energies: Questions for the GLAST and ACT's

    NASA Technical Reports Server (NTRS)

    Thompson, Dave

    2008-01-01

    The recent announcement by the MAGIC team of pulsed gamma rays from the Crab Pulsar above 25 GeV and the launch of AGILE and the Gamma-ray Large Area Space Telescope (GLAST) offer the promise of major progress in understanding the most extreme emission from pulsar magnetospheres. While waiting for detailed results, we can formulate questions to be addressed, based on past measurements and theoretical modeling. This brief review will highlight promising approaches for research into high-energy pulsed radiation.

  9. The LHCb silicon tracker: running experience

    NASA Astrophysics Data System (ADS)

    Saornil Gamarra, S.

    2013-02-01

    The LHCb Silicon Tracker is part of the main tracking system of the LHCb detector at the LHC. It measures very precisely the particle trajectories coming from the interaction point in the region of high occupancies around the beam axis. It covers the full acceptance angle in front of the dipole magnet in the Tracker Turicensis station and the innermost part around the beam axis in the three Inner Tracker stations downstream of the magnet. The Silicon Tracker covers a sensitive area of 12 m2 using silicon micro-strip sensors with very long readout strips. We report on running experience for the experiment. Focussing on electronic and hardware issues we describe some of the lessons learned and pitfalls encountered after three years of successful operation.

  10. Instruction manual for Sandia's laser tracker

    SciTech Connect

    Bauhs, K.C.

    1982-06-01

    This report is a supplement to SAND80-2049/1. It contains additional drawings and information for hardware described in Volume 1, more troubleshooting procedures for several systems in the Laser Tracker Facility, and corrections for volume 1.

  11. My Game Plan: Food and Activity Tracker

    MedlinePlus

    ... THIS WEEK… FOR CUTTING FAT GRAMS: FOR CUTTING CALORIES: FOR GETTING MORE PHYSICAL ACTIVITY: FROM — TO HHS' ... AND DRINK TRACKER AMOUNT /NAME /DESCRIPTION FAT GRAMS CALORIES 1/2 cup oatmeal 1 73 1 cup ...

  12. Commissioning of the Cms Tracker Outer Barrel

    NASA Astrophysics Data System (ADS)

    Bloch, Christoph

    2006-04-01

    Fully equipped final substructures of the CMS Tracker are installed in a dedicated mechanical support, the Cosmic Rack, providing a geometry suitable for tracking cosmic muons, and equipped with a dedicated trigger that allows the selection of tracks synchronous with the fast readout electronics. Data collected at room temperature and at the tracker operating temperature of -10°C can be used to test reconstruction and alignment algorithms for the tracker, as well as to perform a detailed qualification of the geometry and the functionality of the structures at different temperatures. The CMS Monte Carlo simulation has been adapted to the geometry of the cosmic rack, and the comparison with the data will provide a valuable test to improve the tracker simulation in CMS.

  13. Silicon Tracker Design for the ILC

    SciTech Connect

    Nelson, T.; /SLAC

    2005-07-27

    The task of tracking charged particles in energy frontier collider experiments has been largely taken over by solid-state detectors. While silicon microstrip trackers offer many advantages in this environment, large silicon trackers are generally much more massive than their gaseous counterparts. Because of the properties of the machine itself, much of the material that comprises a typical silicon microstrip tracker can be eliminated from a design for the ILC. This realization is the inspiration for a tracker design using lightweight, short, mass-producible modules to tile closed, nested cylinders with silicon microstrips. This design relies upon a few key technologies to provide excellent performance with low cost and complexity. The details of this concept are discussed, along with the performance and status of the design effort.

  14. Power Studies for the CMS Pixel Tracker

    SciTech Connect

    Todri, A.; Turqueti, M.; Rivera, R.; Kwan, S.; /Fermilab

    2009-01-01

    The Electronic Systems Engineering Department of the Computing Division at the Fermi National Accelerator Laboratory is carrying out R&D investigations for the upgrade of the power distribution system of the Compact Muon Solenoid (CMS) Pixel Tracker at the Large Hadron Collider (LHC). Among the goals of this effort is that of analyzing the feasibility of alternative powering schemes for the forward tracker, including DC to DC voltage conversion techniques using commercially available and custom switching regulator circuits. Tests of these approaches are performed using the PSI46 pixel readout chip currently in use at the CMS Tracker. Performance measures of the detector electronics will include pixel noise and threshold dispersion results. Issues related to susceptibility to switching noise will be studied and presented. In this paper, we describe the current power distribution network of the CMS Tracker, study the implications of the proposed upgrade with DC-DC converters powering scheme and perform noise susceptibility analysis.

  15. Power distribution studies for CMS forward tracker

    SciTech Connect

    Todri, A.; Turqueti, M.; Rivera, R.; Kwan, S.

    2009-01-01

    The Electronic Systems Engineering Department of the Computing Division at the Fermi National Accelerator Laboratory is carrying out R&D investigations for the upgrade of the power distribution system of the Compact Muon Solenoid (CMS) Pixel Tracker at the Large Hadron Collider (LHC). Among the goals of this effort is that of analyzing the feasibility of alternative powering schemes for the forward tracker, including DC to DC voltage conversion techniques using commercially available and custom switching regulator circuits. Tests of these approaches are performed using the PSI46 pixel readout chip currently in use at the CMS Tracker. Performance measures of the detector electronics will include pixel noise and threshold dispersion results. Issues related to susceptibility to switching noise will be studied and presented. In this paper, we describe the current power distribution network of the CMS Tracker, study the implications of the proposed upgrade with DC-DC converters powering scheme and perform noise susceptibility analysis.

  16. My Game Plan: Food and Activity Tracker

    MedlinePlus

    ... MY GAME PLAN THIS WEEK… FOR CUTTING FAT GRAMS: FOR CUTTING CALORIES: FOR GETTING MORE PHYSICAL ACTIVITY: ... FOOD AND DRINK TRACKER AMOUNT /NAME /DESCRIPTION FAT GRAMS CALORIES 1/2 cup oatmeal 1 73 1 ...

  17. Search for tracker potentials in quintessence theory

    NASA Astrophysics Data System (ADS)

    Johri, Vinod B.

    2002-12-01

    We report a significant finding in quintessence theory that scalar fields with tracker potentials have a model-independent scaling behaviour in the expanding universe. So far, widely discussed exponential, power law or hyperbolic potentials can simply mimic the tracking behaviour over a limited range of redshift. A new version of the tracker field theory is proposed and it is shown that in the small redshift range where the variation of the tracking parameter ɛ may be taken to be negligible, the differential equation of generic potentials leads to hyperbolic sine and hyperbolic cosine potentials which may approximate a tracker field in the present-day universe. We have plotted the variation of the tracker potential and the equation of state of the tracker field as a function of the redshift z for the model-independent relation derived from tracker field theory; we have also plotted the variation of V(Φ) in terms of the scalar field Φ for the chosen hyperbolic cosine function and have compared it with the curves obtained by the reconstruction of V(Φ) from real observational data from the supernovae.

  18. Technology transfer: Imaging tracker to robotic controller

    NASA Technical Reports Server (NTRS)

    Otaguro, M. S.; Kesler, L. O.; Land, Ken; Erwin, Harry; Rhoades, Don

    1988-01-01

    The transformation of an imaging tracker to a robotic controller is described. A multimode tracker was developed for fire and forget missile systems. The tracker locks on to target images within an acquisition window using multiple image tracking algorithms to provide guidance commands to missile control systems. This basic tracker technology is used with the addition of a ranging algorithm based on sizing a cooperative target to perform autonomous guidance and control of a platform for an Advanced Development Project on automation and robotics. A ranging tracker is required to provide the positioning necessary for robotic control. A simple functional demonstration of the feasibility of this approach was performed and described. More realistic demonstrations are under way at NASA-JSC. In particular, this modified tracker, or robotic controller, will be used to autonomously guide the Man Maneuvering Unit (MMU) to targets such as disabled astronauts or tools as part of the EVA Retriever efforts. It will also be used to control the orbiter's Remote Manipulator Systems (RMS) in autonomous approach and positioning demonstrations. These efforts will also be discussed.

  19. The First Fermi LAT Supernova Remnant Catalog

    NASA Astrophysics Data System (ADS)

    Acero, F.; Ackermann, M.; Ajello, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bellazzini, R.; Bissaldi, E.; Blandford, R. D.; Bloom, E. D.; Bonino, R.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caputo, R.; Caragiulo, M.; Caraveo, P. A.; Casandjian, J. M.; Cavazzuti, E.; Cecchi, C.; Chekhtman, A.; Chiang, J.; Chiaro, G.; Ciprini, S.; Claus, R.; Cohen, J. M.; Cohen-Tanugi, J.; Cominsky, L. R.; Condon, B.; Conrad, J.; Cutini, S.; D’Ammando, F.; de Angelis, A.; de Palma, F.; Desiante, R.; Digel, S. W.; Di Venere, L.; Drell, P. S.; Drlica-Wagner, A.; Favuzzi, C.; Ferrara, E. C.; Franckowiak, A.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Gomez-Vargas, G. A.; Grenier, I. A.; Grondin, M.-H.; Guillemot, L.; Guiriec, S.; Gustafsson, M.; Hadasch, D.; Harding, A. K.; Hayashida, M.; Hays, E.; Hewitt, J. W.; Hill, A. B.; Horan, D.; Hou, X.; Iafrate, G.; Jogler, T.; Jóhannesson, G.; Johnson, A. S.; Kamae, T.; Katagiri, H.; Kataoka, J.; Katsuta, J.; Kerr, M.; Knödlseder, J.; Kocevski, D.; Kuss, M.; Laffon, H.; Lande, J.; Larsson, S.; Latronico, L.; Lemoine-Goumard, M.; Li, J.; Li, L.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Magill, J.; Maldera, S.; Marelli, M.; Mayer, M.; Mazziotta, M. N.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monzani, M. E.; Moretti, E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nemmen, R.; Nuss, E.; Ohsugi, T.; Omodei, N.; Orienti, M.; Orlando, E.; Ormes, J. F.; Paneque, D.; Perkins, J. S.; Pesce-Rollins, M.; Petrosian, V.; Piron, F.; Pivato, G.; Porter, T. A.; Rainò, S.; Rando, R.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Renaud, M.; Reposeur, T.; Rousseau, R.; Saz Parkinson, P. M.; Schmid, J.; Schulz, A.; Sgrò, C.; Siskind, E. J.; Spada, F.; Spandre, G.; Spinelli, P.; Strong, A. W.; Suson, D. J.; Tajima, H.; Takahashi, H.; Tanaka, T.; Thayer, J. B.; Thompson, D. J.; Tibaldo, L.; Tibolla, O.; Torres, D. F.; Tosti, G.; Troja, E.; Uchiyama, Y.; Vianello, G.; Wells, B.; Wood, K. S.; Wood, M.; Yassine, M.; den Hartog, P. R.; Zimmer, S.

    2016-05-01

    To uniformly determine the properties of supernova remnants (SNRs) at high energies, we have developed the first systematic survey at energies from 1 to 100 GeV using data from the Fermi Large Area Telescope (LAT). Based on the spatial overlap of sources detected at GeV energies with SNRs known from radio surveys, we classify 30 sources as likely GeV SNRs. We also report 14 marginal associations and 245 flux upper limits. A mock catalog in which the positions of known remnants are scrambled in Galactic longitude allows us to determine an upper limit of 22% on the number of GeV candidates falsely identified as SNRs. We have also developed a method to estimate spectral and spatial systematic errors arising from the diffuse interstellar emission model, a key component of all Galactic Fermi LAT analyses. By studying remnants uniformly in aggregate, we measure the GeV properties common to these objects and provide a crucial context for the detailed modeling of individual SNRs. Combining our GeV results with multiwavelength (MW) data, including radio, X-ray, and TeV, we demonstrate the need for improvements to previously sufficient, simple models describing the GeV and radio emission from these objects. We model the GeV and MW emission from SNRs in aggregate to constrain their maximal contribution to observed Galactic cosmic rays.

  20. Catching blazars in the act exlamation GLAST triggers for TeV observation of blazars

    SciTech Connect

    Behera, Bagmeet; Wagner, Stefan J.

    2008-12-24

    The double humped SED (Spectral Energy Distribution) of blazars, and their flaring phenomena can be explained by various leptonic and hadronic models. However, accurate modeling of the high frequency component and clear identification of the correct emission mechanism would require simultaneous measurements in both the MeV-GeV band and the TeV band. Due to the differences in the sensitivity and the field of view of the instruments required to do these measurements, it is essential to identify active states of blazars likely to be detected with TeV instruments.Using a reasonable intergalactic attenuation model, various extrapolations of the EGRET spectra, as a proxy for GLAST (Gamma-ray Large Area Space Telescope) measurements, are made into TeV energies for selecting EGRET blazars expected to be VHE-bright. Furthermore, estimates of the threshold fluxes at GLAST energies are provided, at which sources are expected to be detectable at TeV energies, with Cherenkov telescopes like HESS, MAGIC or VERITAS.

  1. Effects of erythropoietin preconditioning on rat cerebral ischemia-reperfusion injury and the GLT-1/GLAST pathway

    PubMed Central

    YU, DAIHUA; FAN, YUANHUA; SUN, XUDE; YAO, LINONG; CHAI, WEI

    2016-01-01

    The aim of the present study was to investigate whether erythropoietin (EPO) preconditioning affects the expression of glutamate transporter 1 (GLT-1) and glutamate aspartate transporter (GLAST) and protects against rat cerebral ischemia-reperfusion injury. A total of 140 Sprague Dawley rats were randomly assigned to one of the following four groups: Sham, EPO-sham, middle cerebral artery occlusion (MCAO) and EPO-MCAO. Neurological function scores were obtained 24, 36 and 72 h after reperfusion. Seventy-two hours after the induction of cerebral ischemia-reperfusion, the number of apoptotic neural cells and the cerebral infarct volume of each group were measured. The mRNA levels of GLT-1 and GLAST were determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis, while the GLT-1 and GLAST protein levels were assessed using western blotting. The cerebral infarct volume was significantly increased in the MCAO group compared with that in the sham group (P<0.01); however, the infarct volume of the EPO-MCAO group was significantly lower than that of the MCAO group (P<0.01). In addition, the number of apoptotic cells found in the MCAO group was higher than that in the sham group (P<0.01), but the number of apoptotic cells in the EPO-MCAO group was significantly lower than that in the MCAO group (P<0.01). The GLT-1 and GLAST mRNA and protein levels were significantly decreased 72 h after the cerebral ischemia-reperfusion (P<0.01) compared with those in the sham group, whereas the same levels were increased significantly in the EPO-MCAO group relative to those in the MCAO group (P<0.01). In conclusion, EPO preconditioning protected against cerebral ischemia-reperfusion injury and upregulated the GLT-1 and GLAST expression. PMID:26893639

  2. Development of a digital mobile solar tracker

    NASA Astrophysics Data System (ADS)

    Baidar, S.; Kille, N.; Ortega, I.; Sinreich, R.; Thomson, D.; Hannigan, J.; Volkamer, R.

    2015-11-01

    We have constructed and deployed a fast digital solar tracker aboard a moving ground-based platform. The tracker consists of two rotating mirrors, a lens, an imaging camera, and a motion compensation system that provides the Euler angles of the mobile platform in real time. The tracker can be simultaneously coupled to UV-Vis and FTIR spectrometers making it a versatile tool to measure the absorption of trace gases using solar incoming radiation. The integrated system allows the tracker to operate autonomously while the mobile laboratory is in motion. Mobile direct sun Differential Optical Absorption Spectroscopy (mobile DS-DOAS) observations using this tracker were conducted during summer 2014 as part of the Front Range Photochemistry and Pollution Experiment (FRAPPE) in Colorado, USA. We demonstrate an angular precision of 0.052° (about 1/10 of the solar disk diameter) during research drives, and verify this tracking precision from measurements of the center to limb darkening (CLD, the changing appearance of Fraunhofer lines) in the mobile DS-DOAS spectra. The high photon flux from direct sun observation enables measurements of nitrogen dioxide (NO2) slant columns with high temporal resolution, and reveals spatial detail in the variations of NO2 vertical column densities (VCDs). The NO2 VCD from DS-DOAS is compared with a co-located MAX-DOAS instrument. Overall good agreement is observed amid a highly heterogeneous air mass.

  3. Development of a digital mobile solar tracker

    NASA Astrophysics Data System (ADS)

    Baidar, Sunil; Kille, Natalie; Ortega, Ivan; Sinreich, Roman; Thomson, David; Hannigan, James; Volkamer, Rainer

    2016-03-01

    We have constructed and deployed a fast digital solar tracker aboard a moving ground-based platform. The tracker consists of two rotating mirrors, a lens, an imaging camera, and a motion compensation system that provides the Euler angles of the mobile platform in real time. The tracker can be simultaneously coupled to UV-Vis and Fourier transform infrared spectrometers, making it a versatile tool to measure the absorption of trace gases using solar incoming radiation. The integrated system allows the tracker to operate autonomously while the mobile laboratory is in motion. Mobile direct sun differential optical absorption spectroscopy (mobile DS-DOAS) observations using this tracker were conducted during summer 2014 as part of the Front Range Air Pollution and Photochemistry Experiment (FRAPPE) in Colorado, USA. We demonstrate an angular precision of 0.052° (about 1/10 of the solar disk diameter) during research drives and verify this tracking precision from measurements of the center to limb darkening (CLD, the changing appearance of Fraunhofer lines) in the mobile DS-DOAS spectra. The high photon flux from direct sun observation enables measurements of nitrogen dioxide (NO2) slant columns with high temporal resolution and reveals spatial detail in the variations of NO2 vertical column densities (VCDs). The NO2 VCD from DS-DOAS is compared with a co-located MAX-DOAS instrument. Overall good agreement is observed amid a highly heterogeneous air mass.

  4. Star Tracker Performance Estimate with IMU

    NASA Technical Reports Server (NTRS)

    Aretskin-Hariton, Eliot D.; Swank, Aaron J.

    2015-01-01

    A software tool for estimating cross-boresight error of a star tracker combined with an inertial measurement unit (IMU) was developed to support trade studies for the Integrated Radio and Optical Communication project (iROC) at the National Aeronautics and Space Administration Glenn Research Center. Typical laser communication systems, such as the Lunar Laser Communication Demonstration (LLCD) and the Laser Communication Relay Demonstration (LCRD), use a beacon to locate ground stations. iROC is investigating the use of beaconless precision laser pointing to enable laser communication at Mars orbits and beyond. Precision attitude knowledge is essential to the iROC mission to enable high-speed steering of the optical link. The preliminary concept to achieve this precision attitude knowledge is to use star trackers combined with an IMU. The Star Tracker Accuracy (STAcc) software was developed to rapidly assess the capabilities of star tracker and IMU configurations. STAcc determines the overall cross-boresight error of a star tracker with an IMU given the characteristic parameters: quantum efficiency, aperture, apparent star magnitude, exposure time, field of view, photon spread, detector pixels, spacecraft slew rate, maximum stars used for quaternion estimation, and IMU angular random walk. This paper discusses the supporting theory used to construct STAcc, verification of the program and sample results.

  5. Expression of LATS family proteins in ovarian tumors and its significance.

    PubMed

    Xu, Bing; Sun, Duoxiang; Wang, Zhihua; Weng, Haiyan; Wu, Dabao; Zhang, Xuefen; Zhou, Ying; Hu, Weiping

    2015-06-01

    Epithelial ovarian cancer is composed of a diverse group of tumors that can be derived from the fallopian tube, endometrium, or ovary. In this study, we explored the expression levels of LATS family members in ovarian tumors using normal ovaries, fallopian tubes, and endometrium as controls. Immunohistochemistry studies of LATS1, LATS2, Pax8, and calretinin were performed on normal ovary, fallopian tube, normal endometrium, and ovarian tumor sections. Statistical analyses were conducted using the χ(2) test, Fisher exact test, or Kruskal-Wallis H test. Patient survival was analyzed using the Kaplan-Meier method. LATS1 was expressed in normal ovarian epithelia, endometrium, and fallopian tubes, whereas LATS2 expression was observed in the normal fallopian tubes and endometrium. High expressions of LATS1 and LATS2 in serous cystadenomas gradually decreased in borderline cystadenomas and carcinomas, respectively. However, an opposite expression pattern was observed in mucinous tumors. Low expressions of LATS1 and LATS2 were also detected in clear cell carcinoma. Both LATS1 and LATS2 expression levels significantly correlated with recurrence and stage; LATS1 levels were also related with tumor grades in serous carcinoma. However, univariate and multivariate Cox regression analyses revealed that high expression of LATS1 was associated with better prognosis in patients with serous carcinoma. Both LATS1 and LATS2 were not related with the clinical variables in mucinous and clear cell carcinoma. LATS1 expression levels might be a valuable survival indicator in ovarian serous carcinoma. PMID:25841306

  6. Pushing the Limits: High Redshift Fermi-LAT Blazars

    NASA Astrophysics Data System (ADS)

    Ojha, Roopesh; Gasparrini, Dario; Lott, Benoit; Cutini, Sara; Fermi-LAT Collaboration

    2016-01-01

    High-redshift blazars detected by the Fermi Large Area Telescope (LAT) are of great astrophysical import as they are extreme objects whose energetics remain a mystery. Such blazars are intrinsically interesting since they inform us about the evolution of gamma-ray blazars and are, by definition, some of the more luminous blazars in the LAT sample. They are also an excellent tool to study the EBL and thus the gamma-ray horizon. We present the latest high redshift blazar detections in the LAT and discuss some of their implications.

  7. SimTracker, Version 5.0

    SciTech Connect

    2004-08-27

    SimTracker is a product of the Metadata Tools subproject under the ASC Scientific Data Management effort. SimTracker is an extensible web-based application that provides the capability to view and organize large volumes of simulation data. SimTracker automatically generates metadata summaries that provide a quick overview and index to the archived results of simulations. The summaries provide access to the data sets and associated data analysis tools. They include graphical snapshots, pointers to associated simulation input and output files, and assorted annotations. The ability to add personal annotations to simulation data sets is supported. All metadata is stored in XML files suitable for searching by the generator of the data or other scientists.

  8. SimTracker, Version 5.0

    Energy Science and Technology Software Center (ESTSC)

    2004-08-27

    SimTracker is a product of the Metadata Tools subproject under the ASC Scientific Data Management effort. SimTracker is an extensible web-based application that provides the capability to view and organize large volumes of simulation data. SimTracker automatically generates metadata summaries that provide a quick overview and index to the archived results of simulations. The summaries provide access to the data sets and associated data analysis tools. They include graphical snapshots, pointers to associated simulation inputmore » and output files, and assorted annotations. The ability to add personal annotations to simulation data sets is supported. All metadata is stored in XML files suitable for searching by the generator of the data or other scientists.« less

  9. Optical contacting for gravity probe star tracker

    NASA Technical Reports Server (NTRS)

    Wright, J. J.; Zissa, D. E.

    1984-01-01

    A star-tracker telescope, constructed entirely of fused silica elements optically contacted together, has been proposed to provide submilliarc-second pointing accuracy for Gravity Probe. A bibliography and discussion on optical contacting (the bonding of very flat, highly polished surfaces without the use of adhesives) are presented. Then results from preliminary experiments on the strength of optical contacts including a tensile strength test in liquid helium are discussed. Suggestions are made for further study to verify an optical contacting method for the Gravity Probe star-tracker telescope.

  10. Preliminary studies of a chromaticity tracker

    SciTech Connect

    Tan, Cheng-Yang; /Fermilab

    2006-03-01

    A chromaticity tracker based on a method by D. McGinnis is proposed. This method starts with the slow modulation of the accelerating RF which causes the beam to respond to it. This beam modulation can be detected transversely with a Schottky pickup which after phase demodulation, the chromaticity can be calculated from it. However, to perform phase demodulation, the carrier frequency which is the betatron tune needs to be identified. The identification of the carrier frequency falls naturally onto the phase locked loop tune tracker which when locked to the betatron tune outputs this value in real time.

  11. Quintessence reconstructed: New constraints and tracker viability

    SciTech Connect

    Sahlen, Martin; Liddle, Andrew R.; Parkinson, David

    2007-01-15

    We update and extend our previous work reconstructing the potential of a quintessence field from current observational data. We extend the cosmological data set to include new supernova data, plus information from the cosmic microwave background and from baryon acoustic oscillations. We extend the modeling by considering Pade approximant expansions as well as Taylor series, and by using observations to assess the viability of the tracker hypothesis. We find that parameter constraints have improved by a factor of 2, with a strengthening of the preference of the cosmological constant over evolving quintessence models. Present data show some signs, though inconclusive, of favoring tracker models over nontracker models under our assumptions.

  12. A microprocessor-controlled CCD star tracker

    NASA Technical Reports Server (NTRS)

    Salomon, P. M.; Goss, W. C.

    1976-01-01

    The STELLAR (Star Tracker for Economical Long Life Attitude Reference) utilizes an image sensing Charge-Coupled Device (CCD) operating under microprocessor control. This approach results in a new type of high-accuracy star tracker which can be adapted to a wide variety of different space flight applications through software changes only. The STELLAR determines two-axis star positions by computing the element and the interelement interpolated centroid positions of the star images. As many as 10 stars may be tracked simultaneously, providing significantly increased stability and accuracy. A detailed description of the STELLAR is presented along with measurements of system performance obtained from an operating breadboard model.

  13. Monitoring the Low-Energy Gamma-Ray Sky Using Earth Occultation with GLAST GBM

    SciTech Connect

    Case, G. L.; Wilson-Hodge, C. A.; Cherry, M. L.; Kippen, R. M.; Ling, J. C.; Radocinski, R. G.; Wheaton, W. A.

    2007-07-12

    Long term all-sky monitoring of the 20 keV - 2 MeV gamma-ray sky using the Earth occultation technique was demonstrated by the BATSE instrument on the Compton Gamma Ray Observatory. The principles and techniques used for the development of an end-to-end earth occultation data analysis system for BATSE can be extended to the GLAST Burst Monitor (GBM), resulting in multiband light curves and time-resolved spectra in the energy range 8 keV to above 1 MeV for known gamma-ray sources and transient outbursts, as well as the discovery of new sources of gamma-ray emission. In this paper we describe the application of the technique to the GBM. We also present the expected sensitivity for the GBM.

  14. Monitoring the Low-Energy Gamma-Ray Sky Using Earth Occultation with GLAST GBM

    NASA Technical Reports Server (NTRS)

    Case, G.; Wilson-Hodge, C.; Cherry, M.; Kippen, M.; Ling, J.; Radocinski, R.; Wheaton, W.

    2007-01-01

    Long term all-sky monitoring of the 20 keV - 2 MeV gamma-ray sky using the Earth occultation technique was demonstrated by the BATSE instrument on the Compton Gamma Ray Observatory. The principles and techniques used for the development of an end-to-end earth occultation data analysis system for BATSE can be extended to the GLAST Gamma-ray Burst Monitor (GBM), resulting in multiband light curves and time-resolved spectra in the energy range 8 keV to above 1 MeV for known gamma-ray sources and transient outbursts, as well as the discovery of new sources of gamma-ray emission. In this paper we describe the application of the technique to the GBM. We also present the expected sensitivity for the GBM.

  15. What Can GLAST Say About the Origin of Cosmic Rays in Other Galaxies

    SciTech Connect

    Bloom, Elliott

    2000-10-10

    Gamma rays in the band from 20 MeV to 300 GeV, used in combination with data from radio and X-ray bands, provide a powerful tool for studying the origin of cosmic rays in our sister galaxies Andromeda and the Magellanic Clouds. Gamma-ray Large Area Space Telescope (GLAST) will spatially resolve these galaxies and measure the spectrum and intensity of diffuse gamma radiation from the collisions of cosmic rays with gas and dust in them. Observations of Andromeda will give an external perspective on a spiral galaxy like the Milky Way. Observations of the Magellanic Clouds will permit a study of cosmic rays in dwarf irregular galaxies, where the confinement is certainly different and the massive star formation rate is much greater.

  16. Proton Irradiation Response of CsI(Tl) Crystals for the GLAST Calorimeter

    SciTech Connect

    Bergenius, S.; Carius, S.; Carlson, P.; Grove, J.E.; Johansson, G.; Klamra, W.; Nilsson, L.; Pearce, M.; Metzler, S.D.

    2012-04-10

    The electromagnetic calorimeter of the Gamma-Ray Large Area Space Telescope (GLAST) consists of 16 towers of CsI(Tl) crystals. Each tower contains 8 layers of crystals (each 326.0 x 26.7 x 19.9 mm{sup 3}) arranged in a hodoscopic fashion. The crystals are read out at both ends with photodiodes. Crystals produced by Amcrys-H (Ukraine) are used. A full size crystal was irradiated with a 180 MeV proton beam and the radiation induced attenuation was measured. The induced radioactivity of the crystal was also studied. In this paper we will discuss the damage due to proton irradiation and compare this with the expected in-orbit background flux.

  17. Chandra and Swift Observations of Unidentified Fermi-LAT Objects

    NASA Astrophysics Data System (ADS)

    Donato, Davide; Cheung, T.; Gehrels, N.

    2010-03-01

    In the last year we targeted some of the unidentified Fermi-LAT objects (UFOs) at high Galactic latitude with Chandra and Swift in order to determine the basic properties (positions, fluxes, hardness ratios) of all X-ray sources within the Fermi-LAT localization circles. These satellites enable us to detect the X-ray conterparts with a flux limit that is at least an order of magnitude lower than achieved in extant RASS data and to further follow-up at other wavelengths, with the ultimate goal to reveal the nature of these enigmatic gamma-ray sources. Here we present the results obtained with 5 Chandra pointings of high Galactic latitude UFOs in the Fermi-LAT 3-months bright source list. The association of detected X-ray sources within the improved 11-months Fermi-LAT localization circles with available optical and radio observations is discussed.

  18. The Tracker of the CMS Experiment

    SciTech Connect

    Migliore, Ernesto

    2005-10-12

    With more than 200 m2 the Silicon Strip Tracker of the Compact Muon Solenoid (CMS) experiment will be the largest silicon detector ever built. In this contribution the main design considerations and the status of the construction, at about one and a half year after the begin of the production of the modules, are reviewed.

  19. A Heavy Flavor Tracker for STAR

    SciTech Connect

    Xu, Z.; Chen, Y.; Kleinfelder, S.; Koohi, A.; Li, S.; Huang, H.; Tai, A.; Kushpil, V.; Sumbera, M.; Colledani, C.; Dulinski, W.; Himmi,A.; Hu, C.; Shabetai, A.; Szelezniak, M.; Valin, I.; Winter, M.; Miller,M.; Surrow, B.; Van Nieuwenhuizen G.; Bieser, F.; Gareus, R.; Greiner,L.; Lesser, F.; Matis, H.S.; Oldenburg, M.; Ritter, H.G.; Pierpoint, L.; Retiere, F.; Rose, A.; Schweda, K.; Sichtermann, E.; Thomas, J.H.; Wieman, H.; Yamamoto, E.; Kotov, I.

    2005-03-14

    We propose to construct a Heavy Flavor Tracker (HFT) for theSTAR experiment at RHIC. The HFT will bring new physics capabilities toSTAR and it will significantly enhance the physics capabilities of theSTAR detector at central rapidities. The HFT will ensure that STAR willbe able to take heavy flavor data at all luminosities attainablethroughout the proposed RHIC II era.

  20. A Heavy Flavor Tracker for STAR

    SciTech Connect

    Xu, Z.; Chen, Y.; Kleinfelder, S.; Koohi, A.; Li, S.; Huang, H.; Tai, A.; Kushpil, V.; Sumbera, M.; Colledani, C.; Dulinski, W.; Himmi,A.; Hu, C.; Shabetai, A.; Szelezniak, M.; Valin, I.; Winter, M.; Surrow,B.; Van Nieuwenhuizen, G.; Bieser, F.; Gareus, R.; Greiner, L.; Lesser,F.; Matis, H.S.; Oldenburg, M.; Ritter, H.G.; Pierpoint, L.; Retiere, F.; Rose, A.; Schweda, K.; Sichtermann, E.; Thomas, J.H.; Wieman, H.; Yamamoto, E.; Kotov, I.

    2005-03-14

    We propose to construct a Heavy Flavor Tracker (HFT) for the STAR experiment at RHIC. The HFT will bring new physics capabilities to STAR and it will significantly enhance the physics capabilities of the STAR detector at central rapidities. The HFT will ensure that STAR will be able to take heavy flavor data at all luminosities attainable throughout the proposed RHIC II era.

  1. jTracker and Monte Carlo Comparison

    NASA Astrophysics Data System (ADS)

    Selensky, Lauren; SeaQuest/E906 Collaboration

    2015-10-01

    SeaQuest is designed to observe the characteristics and behavior of `sea-quarks' in a proton by reconstructing them from the subatomic particles produced in a collision. The 120 GeV beam from the main injector collides with a fixed target and then passes through a series of detectors which records information about the particles produced in the collision. However, this data becomes meaningful only after it has been processed, stored, analyzed, and interpreted. Several programs are involved in this process. jTracker (sqerp) reads wire or hodoscope hits and reconstructs the tracks of potential dimuon pairs from a run, and Geant4 Monte Carlo simulates dimuon production and background noise from the beam. During track reconstruction, an event must meet the criteria set by the tracker to be considered a viable dimuon pair; this ensures that relevant data is retained. As a check, a comparison between a new version of jTracker and Monte Carlo was made in order to see how accurately jTracker could reconstruct the events created by Monte Carlo. In this presentation, the results of the inquest and their potential effects on the programming will be shown. This work is supported by U.S. DOE MENP Grant DE-FG02-03ER41243.

  2. Phorbol ester-mediated re-expression of endogenous LAT adapter in J.CaM2 cells: a model for dissecting drivers and blockers of LAT transcription.

    PubMed

    Marek-Bukowiec, K; Aguado, E; Miazek, A

    2016-07-01

    Linker for activation of T cells (LAT) is a raft-associated, transmembrane adapter protein critical for T-cell development and function. LAT expression is transiently upregulated upon T-cell receptor (TCR) engagement, but molecular mechanisms conveying TCR signaling to enhanced LAT transcription are not fully understood. Here we found that a Jurkat subline J.CaM2, initially characterized as LAT deficient, conditionally re-expressed LAT upon the treatment with a protein kinase C activator, phorbol 12-myristate 13-acetate (PMA). We took advantage of the above observation for studying cis-elements and trans-acting factors contributing to the activation-induced expression of LAT. We identified a LAT gene region spanning nucleotide position -14 to +357 relative to the ATG start codon as containing novel cis-regulatory elements that were able to promote PMA-induced reporter transcription in the absence of the core LAT promoter. Interestingly, a point mutation in LAT intron 1, identified in J.CaM2 cells, downmodulated LAT promoter activity by 50%. Mithramycin A, a selective Sp1 DNA-binding inhibitor, abolished LAT expression upon PMA treatment as did calcium ionophore ionomycin (Iono) and valproic acid (VPA), widely used as an anti-epileptic drug. Our data introduce J.CaM2 cells as a model for dissecting drivers and blockers of activation induced expression of LAT. PMID:27278128

  3. Phorbol ester-mediated re-expression of endogenous LAT adapter in J.CaM2 cells: a model for dissecting drivers and blockers of LAT transcription

    PubMed Central

    Marek-Bukowiec, K; Aguado, E; Miazek, A

    2016-01-01

    Linker for activation of T cells (LAT) is a raft-associated, transmembrane adapter protein critical for T-cell development and function. LAT expression is transiently upregulated upon T-cell receptor (TCR) engagement, but molecular mechanisms conveying TCR signaling to enhanced LAT transcription are not fully understood. Here we found that a Jurkat subline J.CaM2, initially characterized as LAT deficient, conditionally re-expressed LAT upon the treatment with a protein kinase C activator, phorbol 12-myristate 13-acetate (PMA). We took advantage of the above observation for studying cis-elements and trans-acting factors contributing to the activation-induced expression of LAT. We identified a LAT gene region spanning nucleotide position −14 to +357 relative to the ATG start codon as containing novel cis-regulatory elements that were able to promote PMA-induced reporter transcription in the absence of the core LAT promoter. Interestingly, a point mutation in LAT intron 1, identified in J.CaM2 cells, downmodulated LAT promoter activity by 50%. Mithramycin A, a selective Sp1 DNA-binding inhibitor, abolished LAT expression upon PMA treatment as did calcium ionophore ionomycin (Iono) and valproic acid (VPA), widely used as an anti-epileptic drug. Our data introduce J.CaM2 cells as a model for dissecting drivers and blockers of activation induced expression of LAT. PMID:27278128

  4. Precision Pointing Control System (PPCS) star tracker test

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Tests performed on the TRW precision star tracker are described. The unit tested was a two-axis gimballed star tracker designed to provide star LOS data to an accuracy of 1 to 2 sec. The tracker features a unique bearing system and utilizes thermal and mechanical symmetry techniques to achieve high precision which can be demonstrated in a one g environment. The test program included a laboratory evaluation of tracker functional operation, sensitivity, repeatibility, and thermal stability.

  5. The first Fermi LAT supernova remnant catalog

    DOE PAGESBeta

    Acero, F.

    2016-05-16

    To uniformly determine the properties of supernova remnants (SNRs) at high energies, we have developed the first systematic survey at energies from 1 to 100 GeV using data from the Fermi Large Area Telescope. Based on the spatial overlap of sources detected at GeV energies with SNRs known from radio surveys, we classify 30 sources as likely GeV SNRs. We also report 14 marginal associations and 245 flux upper limits. A mock catalog in which the positions of known remnants are scrambled in Galactic longitude, allows us to determine an upper limit of 22% on the number of GeV candidatesmore » falsely identified as SNRs. We have also developed a method to estimate spectral and spatial systematic errors arising from the diffuse interstellar emission model, a key component of all Galactic Fermi LAT analyses. By studying remnants uniformly in aggregate, we measure the GeV properties common to these objects and provide a crucial context for the detailed modeling of individual SNRs. Combining our GeV results with multiwavelength (MW) data, including radio, X-ray, and TeV, demonstrates the need for improvements to previously sufficient, simple models describing the GeV and radio emission from these objects. As a result, we model the GeV and MW emission from SNRs in aggregate to constrain their maximal contribution to observed Galactic cosmic rays.« less

  6. Experimental predictions drawn from a computational model of sign-trackers and goal-trackers

    PubMed Central

    Lesaint, Florian; Sigaud, Olivier; Clark, Jeremy J.; Flagel, Shelly B.; Khamassi, Mehdi

    2014-01-01

    Gaining a better understanding of the biological mechanisms underlying the individual variation observed in response to rewards and reward cues could help to identify and treat individuals more prone to disorders of impulsive control, such as addiction. Variation in response to reward cues is captured in rats undergoing autoshaping experiments where the appearance of a lever precedes food delivery. Although no response is required for food to be delivered, some rats (goal-trackers) learn to approach and avidly engage the magazine until food delivery, whereas other rats (sign-trackers) come to approach and engage avidly the lever. The impulsive and often maladaptive characteristics of the latter response are reminiscent of addictive behaviour in humans. In a previous article, we developed a computational model accounting for a set of experimental data regarding sign-trackers and goal-trackers. Here we show new simulations of the model to draw experimental predictions that could help further validate or refute the model. In particular, we apply the model to new experimental protocols such as injecting flupentixol locally into the core of the nucleus accumbens rather than systemically, and lesioning of the core of the nucleus accumbens before or after conditioning. In addition, we discuss the possibility of removing the food magazine during the inter-trial interval. The predictions from this revised model will help us better understand the role of different brain regions in the behaviours expressed by sign-trackers and goal-trackers. PMID:24954026

  7. Experimental predictions drawn from a computational model of sign-trackers and goal-trackers.

    PubMed

    Lesaint, Florian; Sigaud, Olivier; Clark, Jeremy J; Flagel, Shelly B; Khamassi, Mehdi

    2015-01-01

    Gaining a better understanding of the biological mechanisms underlying the individual variation observed in response to rewards and reward cues could help to identify and treat individuals more prone to disorders of impulsive control, such as addiction. Variation in response to reward cues is captured in rats undergoing autoshaping experiments where the appearance of a lever precedes food delivery. Although no response is required for food to be delivered, some rats (goal-trackers) learn to approach and avidly engage the magazine until food delivery, whereas other rats (sign-trackers) come to approach and engage avidly the lever. The impulsive and often maladaptive characteristics of the latter response are reminiscent of addictive behaviour in humans. In a previous article, we developed a computational model accounting for a set of experimental data regarding sign-trackers and goal-trackers. Here we show new simulations of the model to draw experimental predictions that could help further validate or refute the model. In particular, we apply the model to new experimental protocols such as injecting flupentixol locally into the core of the nucleus accumbens rather than systemically, and lesioning of the core of the nucleus accumbens before or after conditioning. In addition, we discuss the possibility of removing the food magazine during the inter-trial interval. The predictions from this revised model will help us better understand the role of different brain regions in the behaviours expressed by sign-trackers and goal-trackers. PMID:24954026

  8. Optical model and calibration of a sun tracker

    NASA Astrophysics Data System (ADS)

    Volkov, Sergei N.; Samokhvalov, Ignatii V.; Cheong, Hai Du; Kim, Dukhyeon

    2016-09-01

    Sun trackers are widely used to investigate scattering and absorption of solar radiation in the Earth's atmosphere. We present a method for optimization of the optical altazimuth sun tracker model with output radiation direction aligned with the axis of a stationary spectrometer. The method solves the problem of stability loss in tracker pointing at the Sun near the zenith. An optimal method for tracker calibration at the measurement site is proposed in the present work. A method of moving calibration is suggested for mobile applications in the presence of large temperature differences and errors in the alignment of the optical system of the tracker.

  9. The CDF online Silicon Vertex Tracker

    NASA Astrophysics Data System (ADS)

    Ashmanskas, W.; Bardi, A.; Bari, M.; Belforte, S.; Berryhill, J.; Bogdan, M.; Carosi, R.; Cerri, A.; Chlachidze, G.; Culbertson, R.; Dell'Orso, M.; Donati, S.; Fiori, I.; Frisch, H. J.; Galeotti, S.; Giannetti, P.; Glagolev, V.; Moneta, L.; Morsani, F.; Nakaya, T.; Passuello, D.; Punzi, G.; Rescigno, M.; Ristori, L.; Sanders, H.; Sarkar, S.; Semenov, A.; Shochet, M.; Speer, T.; Spinella, F.; Wu, X.; Yang, U.; Zanello, L.; Zanetti, A. M.

    2002-06-01

    The CDF Online Silicon Vertex Tracker (SVT) reconstructs 2D tracks by linking hit positions measured by the Silicon Vertex Detector to the Central Outer Chamber tracks found by the eXtremely Fast Tracker (XFT). The system has been completely built and assembled and it is now being commissioned using the first CDF run II data. The precision measurement of the track impact parameter will allow triggering on B hadron decay vertices and thus investigating important areas in the B sector, like CP violation and B s mixing. In this paper we briefly review the architecture and the tracking algorithms implemented in the SVT and we report on the performance of the system achieved in the early phase of CDF run II.

  10. The CDF online silicon vertex tracker

    SciTech Connect

    W. Ashmanskas et al.

    2001-11-02

    The CDF Online Silicon Vertex Tracker reconstructs 2-D tracks by linking hit positions measured by the Silicon Vertex Detector to the Central Outer Chamber tracks found by the eXtremely Fast Tracker. The system has been completely built and assembled and it is now being commissioned using the first CDF run II data. The precision measurement of the track impact parameter will allow triggering on B hadron decay vertices and thus investigating important areas in the B sector, like CP violation and B{sub s} mixing. In this paper we briefly review the architecture and the tracking algorithms implemented in the SVT and we report on the performance of the system achieved in the early phase of CDF run II.

  11. Target for optically activated seekers and trackers

    NASA Astrophysics Data System (ADS)

    Lakin, C. T.; Willett, N. F.

    1984-05-01

    This abstract discloses a target for optically activated seekers and trackers (TOAST) which provides for calibrated and variable target characteristics such as size, intensity, spatial position, color and interfering background. The TOAST has a first ilumination system providing a target light beam through an adjustable iris which controls image size. The target beam passes through a collimator lens which focuses the light at infinity. With the target beam focused at infinity, the motion of an elevation plate lengthens or shortens the distance from the collimator lens to a one motion mirror. The target beam is attenuated by a variable filter driven by a servo-motor, and a color selection process is provided by passing the beam through spectral filters. A background light beam with background imagery is provided to the beamsplitter mirror and mixed with the target image so as to simulate the target environment encountered by an operating optically activated seeker and tracker.

  12. Boronophenylalanine, a boron delivery agent for boron neutron capture therapy, is transported by ATB0,+, LAT1 and LAT2.

    PubMed

    Wongthai, Printip; Hagiwara, Kohei; Miyoshi, Yurika; Wiriyasermkul, Pattama; Wei, Ling; Ohgaki, Ryuichi; Kato, Itsuro; Hamase, Kenji; Nagamori, Shushi; Kanai, Yoshikatsu

    2015-03-01

    The efficacy of boron neutron capture therapy relies on the selective delivery of boron carriers to malignant cells. p-Boronophenylalanine (BPA), a boron delivery agent, has been proposed to be localized to cells through transporter-mediated mechanisms. In this study, we screened aromatic amino acid transporters to identify BPA transporters. Human aromatic amino acid transporters were functionally expressed in Xenopus oocytes and examined for BPA uptake and kinetic parameters. The roles of the transporters in BPA uptake were characterized in cancer cell lines. For the quantitative assessment of BPA uptake, HPLC was used throughout the study. Among aromatic amino acid transporters, ATB(0,+), LAT1 and LAT2 were found to transport BPA with Km values of 137.4 ± 11.7, 20.3 ± 0.8 and 88.3 ± 5.6 μM, respectively. Uptake experiments in cancer cell lines revealed that the LAT1 protein amount was the major determinant of BPA uptake at 100 μM, whereas the contribution of ATB(0,+) became significant at 1000 μM, accounting for 20-25% of the total BPA uptake in MCF-7 breast cancer cells. ATB(0,+), LAT1 and LAT2 transport BPA at affinities comparable with their endogenous substrates, suggesting that they could mediate effective BPA uptake in vivo. The high and low affinities of LAT1 and ATB(0,+), respectively, differentiate their roles in BPA uptake. ATB(0,+), as well as LAT1, could contribute significantly to the tumor accumulation of BPA at clinical dose. PMID:25580517

  13. LATS1 and LATS2 phosphorylate CDC26 to modulate assembly of the tetratricopeptide repeat subcomplex of APC/C.

    PubMed

    Masuda, Kenta; Chiyoda, Tatsuyuki; Sugiyama, Naoyuki; Segura-Cabrera, Aldo; Kabe, Yasuaki; Ueki, Arisa; Banno, Kouji; Banno, Koji; Suematsu, Makoto; Aoki, Daisuke; Ishihama, Yasushi; Saya, Hideyuki; Kuninaka, Shinji

    2015-01-01

    In budding yeast, the Mitotic Exit Network (MEN) regulates anaphase promoting complex/cyclosome (APC/C) via the Dbf2-Cdc14 signaling cascade. Dbf2 kinase phosphorylates and activates Cdc14 phosphatase, which removes the inhibitory phosphorylation of the APC/C cofactor Cdh1. Although each component of the MEN was highly conserved during evolution, there is presently no evidence supporting direct phosphorylation of CDC14 by large tumor suppressor kinase 1 (LATS1), the human counterpart of Dbf2; hence, it is unclear how LATS1 regulates APC/C. Here, we demonstrate that LATS1 phosphorylates the Thr7 (T7) residue of the APC/C component CDC26 directly. Nocodazole-induced phosphorylation of T7 was reduced by knockdown of LATS1 and LATS2 in HeLa cells, indicating that both of these kinases contribute to the phosphorylation of CDC26 in vivo. The T7 residue of CDC26 is critical for its interaction with APC6, a tetratricopeptide repeat-containing subunit of APC/C, and mutation of this residue to Asp (T7D) reduced the interaction of CDC26 with APC6. Replacement of endogenous CDC26 in HeLa cells with exogenous phosphor-mimic T7D-mutated CDC26 increased the elution size of APC/C subunits in a gel filtration assay, implying a change in the APC/C assembly upon phosphorylation of CDC26. Furthermore, T7D-mutated CDC26 promoted the ubiquitination of polo-like kinase 1, a well-known substrate of APC/C. Overall, these results suggest that LATS1/2 are novel kinases involved in APC/C phosphorylation and indicate a direct regulatory link between LATS1/2 and APC/C. PMID:25723520

  14. LATS1 and LATS2 Phosphorylate CDC26 to Modulate Assembly of the Tetratricopeptide Repeat Subcomplex of APC/C

    PubMed Central

    Masuda, Kenta; Chiyoda, Tatsuyuki; Sugiyama, Naoyuki; Segura-Cabrera, Aldo; Kabe, Yasuaki; Ueki, Arisa; Banno, Koji; Suematsu, Makoto; Aoki, Daisuke; Ishihama, Yasushi; Saya, Hideyuki; Kuninaka, Shinji

    2015-01-01

    In budding yeast, the Mitotic Exit Network (MEN) regulates anaphase promoting complex/cyclosome (APC/C) via the Dbf2-Cdc14 signaling cascade. Dbf2 kinase phosphorylates and activates Cdc14 phosphatase, which removes the inhibitory phosphorylation of the APC/C cofactor Cdh1. Although each component of the MEN was highly conserved during evolution, there is presently no evidence supporting direct phosphorylation of CDC14 by large tumor suppressor kinase 1 (LATS1), the human counterpart of Dbf2; hence, it is unclear how LATS1 regulates APC/C. Here, we demonstrate that LATS1 phosphorylates the Thr7 (T7) residue of the APC/C component CDC26 directly. Nocodazole-induced phosphorylation of T7 was reduced by knockdown of LATS1 and LATS2 in HeLa cells, indicating that both of these kinases contribute to the phosphorylation of CDC26 in vivo. The T7 residue of CDC26 is critical for its interaction with APC6, a tetratricopeptide repeat-containing subunit of APC/C, and mutation of this residue to Asp (T7D) reduced the interaction of CDC26 with APC6. Replacement of endogenous CDC26 in HeLa cells with exogenous phosphor-mimic T7D-mutated CDC26 increased the elution size of APC/C subunits in a gel filtration assay, implying a change in the APC/C assembly upon phosphorylation of CDC26. Furthermore, T7D-mutated CDC26 promoted the ubiquitination of polo-like kinase 1, a well-known substrate of APC/C. Overall, these results suggest that LATS1/2 are novel kinases involved in APC/C phosphorylation and indicate a direct regulatory link between LATS1/2 and APC/C. PMID:25723520

  15. Upgrade of the Upstream Tracker at LHCb

    NASA Astrophysics Data System (ADS)

    Andrews, Jason; LHCb Collaboration

    2015-04-01

    The LHCb detector will be upgraded to allow it operate at higher collider luminosity without the need for a hardware trigger stage. Flavor enriched events will be selected in a software based, high level trigger, using fully reconstructed events. This presentation will describe the design, optimization and the expected performance of the Upstream Tracker (UT), which has a critical role in high level trigger scheme.

  16. ILC Vertex Tracker R&D

    SciTech Connect

    Battaglia, Marco; Bussat, Jean-Marie; Contarato, Devis; Denes,Peter; Glesener, Lindsay; Greiner, Leo; Hooberman, Benjamin; Shuman,Derek; Tompkins, Lauren; Vu, Chinh; Bisello, Dario; Giubilato, Piero; Pantano, Devis; Costa, Marco; La Rosa, Alessandro; Bolla, Gino; Bortoletto, Daniela; Children, Isaac

    2007-10-01

    This document summarizes past achievements, current activities and future goals of the R&D program aimed at the design, prototyping and characterization of a full detector module, equipped with monolithic pixel sensors, matching the requirements for the Vertex Tracker at the ILC. We provide a plan of activities to obtain a demonstrator multi-layered vertex tracker equipped with sensors matching the ILC requirements and realistic lightweight ladders in FY11, under the assumption that ILC detector proto-collaborations will be choosing technologies and designs for the Vertex Tracker by that time. The R&D program discussed here started at LBNL in 2004, supported by a Laboratory Directed R&D (LDRD) grant and by funding allocated from the core budget of the LBNL Physics Division and from the Department of Physics at UC Berkeley. Subsequently additional funding has been awarded under the NSF-DOE LCRD program and also personnel have become available through collaborative research with other groups. The aim of the R&D program carried out by our collaboration is to provide a well-integrated, inclusive research effort starting from physics requirements for the ILC Vertex Tracker and addressing Si sensor design and characterization, engineered ladder design, module system issues, tracking and vertex performances and beam test validation. The broad scope of this program is made possible by important synergies with existing know-how and concurrent programs both at LBNL and at the other collaborating institutions. In particular, significant overlaps with LHC detector design, SLHC R&D as well as prototyping for the STAR upgrade have been exploited to optimize the cost per deliverable of our program. This activity is carried out as a collaborative effort together with Accelerator and Fusion Research, the Engineering and the Nuclear Science Divisions at LBNL, INFN and the Department of Physics in Padova, Italy, INFN and the Department of Physics in Torino, Italy and the Department

  17. The First FERMI-LAT Gamma-Ray Burst Catalog

    NASA Technical Reports Server (NTRS)

    Ackermann, M.; Ajello, M.; Asano, K.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Bhat, P. N.; Bissaldi, E.; Bloom, E. D.; Bonamente, E.; Bonnell, J.; Bouvier, A.; Brandt, T. J.; Bregeon, J.; Brigida, M.; Bruel, P.; Burgess, J. Michael; Buson, S.; Byrne, D.; Caliandro, G. A.; Ferrara, E. C.; Gehrels, N.; Guiriec, S.; McEnery, J. E.; Nemmen, R.; Perkins, J. S.; Racusin, J. L.; Thompson, D. J.; Kouveliotou, C.

    2013-01-01

    In three years of observations since the beginning of nominal science operations in 2008 August, the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope has observed high-energy great than (20 MeV) gamma-ray emission from 35 gamma-ray bursts (GRBs). Among these, 28 GRBs have been detected above 100 MeV and 7 GRBs above approximately 20 MeV. The first Fermi-LAT catalog of GRBs is a compilation of these detections and provides a systematic study of high-energy emission from GRBs for the first time. To generate the catalog, we examined 733 GRBs detected by the Gamma-Ray Burst Monitor (GBM) on Fermi and processed each of them using the same analysis sequence. Details of the methodology followed by the LAT collaboration for the GRB analysis are provided. We summarize the temporal and spectral properties of the LAT-detected GRBs. We also discuss characteristics of LAT-detected emission such as its delayed onset and longer duration compared with emission detected by the GBM, its power-law temporal decay at late times, and the fact that it is dominated by a power-law spectral component that appears in addition to the usual Band model.

  18. THE FIRST FERMI-LAT GAMMA-RAY BURST CATALOG

    SciTech Connect

    Ackermann, M.; Ajello, M.; Asano, K.; Axelsson, M.; Baldini, L.; Ballet, J.; Bastieri, D.; Bechtol, K.; Bloom, E. D.; Bellazzini, R.; Bregeon, J.; Bhat, P. N.; Bissaldi, E.; Bonamente, E.; Bonnell, J.; Brandt, T. J.; Bouvier, A. E-mail: giacomov@slac.stanford.edu; and others

    2013-11-01

    In three years of observations since the beginning of nominal science operations in 2008 August, the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope has observed high-energy (∼> 20 MeV) γ-ray emission from 35 gamma-ray bursts (GRBs). Among these, 28 GRBs have been detected above 100 MeV and 7 GRBs above ∼20 MeV. The first Fermi-LAT catalog of GRBs is a compilation of these detections and provides a systematic study of high-energy emission from GRBs for the first time. To generate the catalog, we examined 733 GRBs detected by the Gamma-Ray Burst Monitor (GBM) on Fermi and processed each of them using the same analysis sequence. Details of the methodology followed by the LAT collaboration for the GRB analysis are provided. We summarize the temporal and spectral properties of the LAT-detected GRBs. We also discuss characteristics of LAT-detected emission such as its delayed onset and longer duration compared with emission detected by the GBM, its power-law temporal decay at late times, and the fact that it is dominated by a power-law spectral component that appears in addition to the usual Band model.

  19. The First Fermi-LAT Gamma-Ray Burst Catalog

    NASA Astrophysics Data System (ADS)

    Ackermann, M.; Ajello, M.; Asano, K.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Bhat, P. N.; Bissaldi, E.; Bloom, E. D.; Bonamente, E.; Bonnell, J.; Bouvier, A.; Brandt, T. J.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Burgess, J. Michael; Buson, S.; Byrne, D.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Cecchi, C.; Charles, E.; Chaves, R. C. G.; Chekhtman, A.; Chiang, J.; Chiaro, G.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Connaughton, V.; Conrad, J.; Cutini, S.; D'Ammando, F.; de Angelis, A.; de Palma, F.; Dermer, C. D.; Desiante, R.; Digel, S. W.; Dingus, B. L.; Di Venere, L.; Drell, P. S.; Drlica-Wagner, A.; Dubois, R.; Favuzzi, C.; Ferrara, E. C.; Fitzpatrick, G.; Foley, S.; Franckowiak, A.; Fukazawa, Y.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Goldstein, A.; Granot, J.; Grenier, I. A.; Grove, J. E.; Gruber, D.; Guiriec, S.; Hadasch, D.; Hanabata, Y.; Hayashida, M.; Horan, D.; Hou, X.; Hughes, R. E.; Inoue, Y.; Jackson, M. S.; Jogler, T.; Jóhannesson, G.; Johnson, A. S.; Johnson, W. N.; Kamae, T.; Kataoka, J.; Kawano, T.; Kippen, R. M.; Knödlseder, J.; Kocevski, D.; Kouveliotou, C.; Kuss, M.; Lande, J.; Larsson, S.; Latronico, L.; Lee, S.-H.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Massaro, F.; Mayer, M.; Mazziotta, M. N.; McBreen, S.; McEnery, J. E.; McGlynn, S.; Michelson, P. F.; Mizuno, T.; Moiseev, A. A.; Monte, C.; Monzani, M. E.; Moretti, E.; Morselli, A.; Murgia, S.; Nemmen, R.; Nuss, E.; Nymark, T.; Ohno, M.; Ohsugi, T.; Omodei, N.; Orienti, M.; Orlando, E.; Paciesas, W. S.; Paneque, D.; Panetta, J. H.; Pelassa, V.; Perkins, J. S.; Pesce-Rollins, M.; Piron, F.; Pivato, G.; Porter, T. A.; Preece, R.; Racusin, J. L.; Rainò, S.; Rando, R.; Rau, A.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Reposeur, T.; Ritz, S.; Romoli, C.; Roth, M.; Ryde, F.; Saz Parkinson, P. M.; Schalk, T. L.; Sgrò, C.; Siskind, E. J.; Sonbas, E.; Spandre, G.; Spinelli, P.; Suson, D. J.; Tajima, H.; Takahashi, H.; Takeuchi, Y.; Tanaka, Y.; Thayer, J. G.; Thayer, J. B.; Thompson, D. J.; Tibaldo, L.; Tierney, D.; Tinivella, M.; Torres, D. F.; Tosti, G.; Troja, E.; Tronconi, V.; Usher, T. L.; Vandenbroucke, J.; van der Horst, A. J.; Vasileiou, V.; Vianello, G.; Vitale, V.; von Kienlin, A.; Winer, B. L.; Wood, K. S.; Wood, M.; Xiong, S.; Yang, Z.

    2013-11-01

    In three years of observations since the beginning of nominal science operations in 2008 August, the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope has observed high-energy (gsim 20 MeV) γ-ray emission from 35 gamma-ray bursts (GRBs). Among these, 28 GRBs have been detected above 100 MeV and 7 GRBs above ~20 MeV. The first Fermi-LAT catalog of GRBs is a compilation of these detections and provides a systematic study of high-energy emission from GRBs for the first time. To generate the catalog, we examined 733 GRBs detected by the Gamma-Ray Burst Monitor (GBM) on Fermi and processed each of them using the same analysis sequence. Details of the methodology followed by the LAT collaboration for the GRB analysis are provided. We summarize the temporal and spectral properties of the LAT-detected GRBs. We also discuss characteristics of LAT-detected emission such as its delayed onset and longer duration compared with emission detected by the GBM, its power-law temporal decay at late times, and the fact that it is dominated by a power-law spectral component that appears in addition to the usual Band model.

  20. Fermi-LAT Observations of the LIGO Event GW150914

    NASA Astrophysics Data System (ADS)

    Ackermann, M.; Ajello, M.; Albert, A.; Anderson, B.; Arimoto, M.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Becerra Gonzalez, J.; Bellazzini, R.; Bissaldi, E.; Blandford, R. D.; Bloom, E. D.; Bonino, R.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Britto, R. J.; Bruel, P.; Buehler, R.; Burnett, T. H.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caputo, R.; Caragiulo, M.; Caraveo, P. A.; Casandjian, J. M.; Cavazzuti, E.; Charles, E.; Chekhtman, A.; Chiang, J.; Chiaro, G.; Ciprini, S.; Cohen-Tanugi, J.; Cominsky, L. R.; Condon, B.; Costanza, F.; Cuoco, A.; Cutini, S.; D’Ammando, F.; de Palma, F.; Desiante, R.; Digel, S. W.; Di Lalla, N.; Di Mauro, M.; Di Venere, L.; Domínguez, A.; Drell, P. S.; Dubois, R.; Dumora, D.; Favuzzi, C.; Fegan, S. J.; Ferrara, E. C.; Franckowiak, A.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Giglietto, N.; Giomi, M.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Gomez-Vargas, G. A.; Granot, J.; Green, D.; Grenier, I. A.; Grondin, M.-H.; Grove, J. E.; Guillemot, L.; Guiriec, S.; Hadasch, D.; Harding, A. K.; Hays, E.; Hewitt, J. W.; Hill, A. B.; Horan, D.; Jogler, T.; Jóhannesson, G.; Kamae, T.; Kensei, S.; Kocevski, D.; Kuss, M.; La Mura, G.; Larsson, S.; Latronico, L.; Lemoine-Goumard, M.; Li, J.; Li, L.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Madejski, G. M.; Magill, J.; Maldera, S.; Manfreda, A.; Marelli, M.; Mayer, M.; Mazziotta, M. N.; McEnery, J. E.; Meyer, M.; Michelson, P. F.; Mirabal, N.; Mizuno, T.; Moiseev, A. A.; Monzani, M. E.; Moretti, E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Negro, M.; Nuss, E.; Ohsugi, T.; Omodei, N.; Orienti, M.; Orlando, E.; Ormes, J. F.; Paneque, D.; Perkins, J. S.; Pesce-Rollins, M.; Piron, F.; Pivato, G.; Porter, T. A.; Racusin, J. L.; Rainò, S.; Rando, R.; Razzaque, S.; Reimer, A.; Reimer, O.; Reposeur, T.; Ritz, S.; Rochester, L. S.; Romani, R. W.; Saz Parkinson, P. M.; Sgrò, C.; Simone, D.; Siskind, E. J.; Smith, D. A.; Spada, F.; Spandre, G.; Spinelli, P.; Suson, D. J.; Tajima, H.; Thayer, J. G.; Thayer, J. B.; Thompson, D. J.; Tibaldo, L.; Torres, D. F.; Troja, E.; Uchiyama, Y.; Venters, T. M.; Vianello, G.; Wood, K. S.; Wood, M.; Zaharijas, G.; Zhu, S.; Zimmer, S.

    2016-05-01

    The Fermi Large Area Telescope (LAT) has an instantaneous field of view (FoV) covering ∼ 1/5 of the sky and it completes a survey of the entire sky in high-energy gamma-rays every 3 hr. It enables searches for transient phenomena over timescales from milliseconds to years. Among these phenomena could be electromagnetic counterparts to gravitational wave (GW) sources. In this paper, we present a detailed study of the LAT observations relevant to Laser Interferometer Gravitational-wave Observatory (LIGO) event GW150914, which is the first direct detection of gravitational waves and has been interpreted as being due to the coalescence of two stellar-mass black holes. The localization region for GW150914 was outside the LAT FoV at the time of the GW signal. However, as part of routine survey observations, the LAT observed the entire LIGO localization region within ∼70 minutes of the trigger and thus enabled a comprehensive search for a γ-ray counterpart to GW150914. The study of the LAT data presented here did not find any potential counterparts to GW150914, but it did provide limits on the presence of a transient counterpart above 100 MeV on timescales of hours to days over the entire GW150914 localization region.

  1. Lats1 suppresses centrosome overduplication by modulating the stability of Cdc25B

    PubMed Central

    Mukai, Satomi; Yabuta, Norikazu; Yoshida, Kaori; Okamoto, Ayumi; Miura, Daisaku; Furuta, Yasuhide; Abe, Takaya; Nojima, Hiroshi

    2015-01-01

    Numerical aberration of the centrosome results in chromosome missegregation, eventually leading to chromosomal instability, a hallmark of human tumor malignancy. Large tumor suppressors 1 and 2 (Lats1 and Lats2) are central kinases in the Hippo pathway and regulate development and tumorigenesis by coordinating the balance between cell proliferation and apoptosis. Importantly, Lats1 and Lats2 also play pivotal roles in cell cycle checkpoint and mitosis. The Lats proteins localize at centrosomes, but their centrosomal functions remain elusive. Here, we generated Lats1-null knockout (Lats1−/−) mice and established Lats1-null mouse embryonic fibroblasts (MEFs). In Lats1−/− MEFs, centrosomes were markedly overduplicated, leading to severe mitotic defects such as chromosome missegregation and cytokinesis failure. We also found that Lats1 physically interacts with Cdc25B phosphatase that localizes both at the centrosome and in the nucleus and regulates the linkage between the centrosome cycle and mitotic progression. Although Lats1 did not phosphorylate Cdc25B, loss of Lats1 in MEFs caused abnormal accumulation of Cdc25B protein and hyperactivation of Cdk2 toward nucleophosmin (NPM/B23), one of the licensing factors involved in centriole duplication. Taken together, these data suggest that Lats1 regulates Cdc25B protein level and subsequent Cdk2 activity, thereby suppressing centrosome overduplication during interphase. PMID:26530630

  2. Accuracy of the vivofit activity tracker.

    PubMed

    Alsubheen, Sana'a A; George, Amanda M; Baker, Alicia; Rohr, Linda E; Basset, Fabien A

    2016-08-01

    The purpose of this study was to examine the accuracy of the vivofit activity tracker in assessing energy expenditure and step count. Thirteen participants wore the vivofit activity tracker for five days. Participants were required to independently perform 1 h of self-selected activity each day of the study. On day four, participants came to the lab to undergo BMR and a treadmill-walking task (TWT). On day five, participants completed 1 h of office-type activities. BMR values estimated by the vivofit were not significantly different from the values measured through indirect calorimetry (IC). The vivofit significantly underestimated EE for treadmill walking, but responded to the differences in the inclination. Vivofit underestimated step count for level walking but provided an accurate estimate for incline walking. There was a strong correlation between EE and the exercise intensity. The vivofit activity tracker is on par with similar devices and can be used to track physical activity. PMID:27266422

  3. The CMS Tracker Detector Control System

    NASA Astrophysics Data System (ADS)

    Yousaf Shah, S.; Tsirou, Andromachi; Verdini, Piero Giorgio; Hartmann, Frank; Masetti, Lorenzo; Dirkes, Guido H.; Stringer, Robert; Fahrer, Manuel

    2009-06-01

    The Compact Muon Solenoid DCS (CMS) Silicon Strip Tracker is by far the largest detector ever built in micro-strip technology. It has an active surface area of 198 m 2 consisting of 15,148 silicon modules with 9,316,352 readout channels read via 75,376 Analog Pipeline Voltage (APV) front-end chips and a total of 24,244 sensors. The Detector Control System (DCS) for the Tracker is a distributed control system that operates ˜2000 power supplies for the silicon modules and also monitors its environmental sensors. The DCS receives information from about 10 3 environmental probes (temperature and humidity sensors) located inside the detector's volume and values from these probes are driven through the Programmable Logic Controllers (PLC) of the Detector Safety System (DSS). A total of 10 5 parameters are read out from the dedicated chips in the front-end electronics of the detector via the data acquisition system, and a total of 10 5 parameters are read from the power supply modules. All these parameters are monitored, evaluated and correlated with the detector layout; actions are taken under specific conditions. The hardware for DCS consists of 10 PCs and 10 PLC systems that are continuously running the necessary control and safety routines. The DCS is a fundamental tool for the Tracker operation and its safety.

  4. A Southern Sky Survey with Fermi LAT and ASKAP

    SciTech Connect

    Cameron, Robert A.; /SLAC /KIPAC, Menlo Park

    2010-04-29

    We present the prospects for a future joint gamma-ray and radio survey of southern hemisphere sources using the Fermi Large Area Telescope (LAT) and the upcoming Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope. ASKAP is a next generation radio telescope designed to perform surveys at GHz frequencies at a much higher survey speed than previous radio telescopes, and is scheduled to start engineering observations in 2011. The survey capabilities of both Fermi LAT and ASKAP are described, and the planned science surveys for ASKAP are summarized. We give some expected details of the Variable and Slow Transient (VAST) survey using ASKAP, which will search for transients on timescales from 5 seconds to years. Some observational properties of faint and transient sources seen at gamma-ray and radio wavelengths are summarized, and prospects and strategies for using ASKAP survey data for LAT source counterpart identification are summarized.

  5. Robust visual tracking with dual spatio-temporal context trackers

    NASA Astrophysics Data System (ADS)

    Sun, Shiyan; Zhang, Hong; Yuan, Ding

    2015-12-01

    Visual tracking is a challenging problem in computer vision. Recent years, significant numbers of trackers have been proposed. Among these trackers, tracking with dense spatio-temporal context has been proved to be an efficient and accurate method. Other than trackers with online trained classifier that struggle to meet the requirement of real-time tracking task, a tracker with spatio-temporal context can run at hundreds of frames per second with Fast Fourier Transform (FFT). Nevertheless, the performance of the tracker with Spatio-temporal context relies heavily on the learning rate of the context, which restricts the robustness of the tracker. In this paper, we proposed a tracking method with dual spatio-temporal context trackers that hold different learning rate during tracking. The tracker with high learning rate could track the target smoothly when the appearance of target changes, while the tracker with low learning rate could percepts the occlusion occurring and continues to track when the target starts to emerge again. To find the target among the candidates from these two trackers, we adopt Normalized Correlation Coefficient (NCC) to evaluate the confidence of each sample. Experimental results show that the proposed algorithm performs robustly against several state-of-the-art tracking methods.

  6. Dark matter and gamma-rays from Draco: MAGIC, GLAST and CACTUS

    SciTech Connect

    Bergstrom, Lars; Hooper, Dan; /Fermilab

    2005-12-01

    The dwarf spheroidal galaxy Draco has long been considered likely to be one of the brightest point sources of gamma-rays generated through dark matter annihilations. Recent studies of this object have found that it remains largely intact from tidal striping, and may be more massive than previously thought. In this article, we revisit Draco as a source of dark matter annihilation radiation, with these new observational constraints in mind. We discuss the prospects for the experiments MAGIC and GLAST to detect dark matter in Draco, as well as constraints from the observations of EGRET. We also discuss the possibility that the CACTUS experiment has already detected gamma-rays from Draco. We find that it is difficult to generate the flux reported by CACTUS without resorting to non-thermally produced WIMPs and/or a density spike in Draco's dark matter distribution due to the presence of an intermediate mass black hole. We also find that for most annihilation modes, a positive detection of Draco by CACTUS would be inconsistent with the lack of events seen by EGRET.

  7. Dark matter and gamma rays from Draco: MAGIC, GLAST and CACTUS

    SciTech Connect

    Bergstroem, Lars; Hooper, Dan

    2006-03-15

    The dwarf spheroidal galaxy Draco has long been considered likely to be one of the brightest point sources of gamma rays generated through dark matter annihilations. Recent studies of this object have found that it remains largely intact from tidal striping, and may be more massive than previously thought. In this article, we revisit Draco as a source of dark matter annihilation radiation, with these new observational constraints in mind. We discuss the prospects for the experiments MAGIC and GLAST to detect dark matter in Draco, as well as constraints from the observations of EGRET. We also discuss the possibility that the CACTUS experiment has already detected gamma rays from Draco. We find that it is difficult to generate the flux reported by CACTUS without resorting to nonthermally produced WIMPs and/or a density spike in Draco's dark matter distribution due to the presence of an intermediate mass black hole. We also find that for most annihilation modes, a positive detection of Draco by CACTUS would be inconsistent with the lack of events seen by EGRET.

  8. High Energy Gamma-Ray Emission from Gamma-Ray Bursts - Before GLAST

    SciTech Connect

    Fan, Yi-Zhong; Piran, Tsvi

    2011-11-29

    Gamma-ray bursts (GRBs) are short and intense emission of soft {gamma}-rays, which have fascinated astronomers and astrophysicists since their unexpected discovery in 1960s. The X-ray/optical/radio afterglow observations confirm the cosmological origin of GRBs, support the fireball model, and imply a long-activity of the central engine. The high-energy {gamma}-ray emission (> 20 MeV) from GRBs is particularly important because they shed some lights on the radiation mechanisms and can help us to constrain the physical processes giving rise to the early afterglows. In this work, we review observational and theoretical studies of the high-energy emission from GRBs. Special attention is given to the expected high-energy emission signatures accompanying the canonical early-time X-ray afterglow that was observed by the Swift X-ray Telescope. We also discuss the detection prospect of the upcoming GLAST satellite and the current ground-based Cerenkov detectors.

  9. Gamma-ray Emission from the Sun: A Study with EGRET Data and Perspectives for GLAST

    NASA Astrophysics Data System (ADS)

    Orlando, Elena; Strong, A. W.

    2008-03-01

    The Sun has recently been predicted to be an extended source of gamma-ray emission, produced by inverse-Compton (IC) scattering of cosmic-ray electrons on the solar radiation field. The emission was predicted to be extended and a confusing foreground for the diffuse extragalactic background even at large angular distances from the Sun. The solar disk is also expected to be a steady gamma-ray source. Analyzing the EGRET database, we find evidence of emission from the solar disk and its halo (Orlando and Strong 2008,arXiv:0801.2178). The observations are compared with our model for the extended emission. The spectrum of the solar disk emission and the spectrum of the extended emission have been obtained. The spectrum of the moon is also given. The observed intensity distribution and the flux are consistent with the predicted model of IC gamma-rays from the halo around the Sun. This emission is expected to be readily detectable in the future by GLAST, and we describe the perspectives for what can be learned from this upcoming mission.

  10. Why do intimate partners live apart? Evidence on LAT relationships across Europe

    PubMed Central

    Liefbroer, Aart C.; Poortman, Anne-Rigt; Seltzer, Judith A.

    2015-01-01

    BACKGROUND Most research asks whether or not cohabitation has come to rival marriage. Little is known about the meaning of living apart together (LAT) relationships, and whether LAT is an alternative to marriage and cohabitation or a dating relationship. OBJECTIVE We examine across Europe: (1) the prevalence of LAT, (2) the reasons for LAT, and (3) the correlates of (a) LAT relationships vis-à-vis being single, married, or cohabiting, and (b) different types of LAT union. METHODS Using Generations and Gender Survey data from ten Western and Eastern European countries, we present descriptive statistics about LATs and estimate multinominal logistic regression models to assess the correlates of being in different types of LAT unions. RESULTS LAT relationships are uncommon, but they are more common in Western than Eastern Europe. Most people in LAT unions intend to live together but are apart for practical reasons. LAT is more common among young people, those enrolled in higher education, people with liberal attitudes, highly educated people, and those who have previously cohabited or been married. Older people and divorced or widowed persons are more likely to choose LAT to maintain independence. Surprisingly, attitudinal and educational differences are more pronounced in Eastern Europe than in Western Europe. CONCLUSIONS A tentative conclusion is that LAT is more often a stage in the union formation process than an alternative to marriage and cohabitation. Yet some groups do view LAT as substituting for marriage and cohabitation, and these groups differ between East and West. In Eastern Europe a cultural, highly educated elite seems to be the first to resist traditional marriage norms and embrace LAT (and cohabitation) as alternative living arrangements, whereas this is less the case in Western Europe. In Western Europe, LAT unions are mainly an alternative for persons who have been married before or had children in a prior relationship. PMID:26085812

  11. Mutation analysis of large tumor suppressor genes LATS1 and LATS2 supports a tumor suppressor role in human cancer.

    PubMed

    Yu, Tian; Bachman, John; Lai, Zhi-Chun

    2015-01-01

    In recent years, human cancer genome projects provide unprecedented opportunities for the discovery of cancer genes and signaling pathways that contribute to tumor development. While numerous gene mutations can be identified from each cancer genome, what these mutations mean for cancer is a challenging question to address, especially for those from less understood putative new cancer genes. As a powerful approach, in silico bioinformatics analysis could efficiently sort out mutations that are predicted to damage gene function. Such an analysis of human large tumor suppressor genes, LATS1 and LATS2, has been carried out and the results support a role of hLATS1//2 as negative growth regulators and tumor suppressors. PMID:25482410

  12. A coherent frequency-bearing tracker

    NASA Astrophysics Data System (ADS)

    Ohlms, D. E.; Cohen, A. O.; Hampton, M. L.; Johnson, G. W.

    The passive measurement of target bearing can be achieved by estimating the phase difference between spatially separated observations of a narrow-band signal. The estimation of this phase difference requires algorithms to track variations in received frequency and the phase difference. This paper presents such an algorithm: a coherently coupled frequency-bearing tracker (CCFBT). The CCFBT is derived from extended Kalman filter theory. A linearized covariance analysis predicts performance above threshold, and an approximate rule predicts threshold. Simulation results verify the covariance analysis and threshold predictions.

  13. Babar Silicon Vertex Tracker: Status and Prospects

    SciTech Connect

    Re, V.; Bondioli, M.; Bruinsma, M.; Curry, S.; Kirkby, D.; Berryhill, J.; Burke, S.; Callahan, D.; Campagnari, C.; Cunha, A.; Dahmes, B.; Hale, D.; Kyre, S.; Richman, J.; Stoner, J.; Verkerke, W.; Beck, T.; Eisner, A.M.; Kroseberg, J.; Lockman, W.S.; Nesom, G.; /INFN, Pavia /Pavia U. /UC, Irvine /UC, Santa Barbara /UC, Santa Cruz /INFN, Ferrara /Ferrara U. /LBL, Berkeley /Maryland U. /INFN, Milan /Milan U. /NIKHEF, Amsterdam /INFN, Pisa /Pisa U. /Princeton U. /UC, Riverside /SLAC /INFN, Turin /Turin U. /INFN, Trieste /Trieste U.

    2006-04-27

    The BABAR Silicon Vertex Tracker (SVT) has been efficiently operated for six years since the start of data taking in 1999. Due to higher than expected background levels some unforeseen effects have appeared. We discuss: a shift in the pedestal for the channels of the AToM readout chips that are most exposed to radiation; an anomalous increase in the bias leakage current for the modules in the outer layers. Estimates of future radiation doses and occupancies are shown together with the extrapolated detector performance and lifetime, in light of the new observations.

  14. A multi-hypothesis tracker for clicking whales.

    PubMed

    Baggenstoss, Paul M

    2015-05-01

    This paper describes a tracker specially designed to track clicking beaked whales using widely spaced bottom-mounted hydrophones, although it can be adapted to different species and sensors. The input to the tracker is a sequence of static localization solutions obtained using time difference of arrival information at widely spaced hydrophones. To effectively handle input localizations with high ambiguity, the tracker is based on multi-hypothesis tracker concepts, so it considers all potential association hypotheses and keeps a large number of potential tracks in memory. The method is demonstrated on actual data and shown to successfully track multiple beaked whales at depth. PMID:25994688

  15. Rover odometry aided by a star tracker

    NASA Astrophysics Data System (ADS)

    Gammell, J. D.; Tong, Chi Hay; Berczi, P.; Anderson, S.; Barfoot, T. D.; Enright, J.

    This paper develops a practical framework for estimating rover position in full-dark conditions by correcting relative odometric estimates with periodic, absolute-attitude measurements from a star tracker. The framework is validated using just under 2.5 kilometres of field data gathered at the University of Toronto's Koffler Scientific Reserve at Jokers Hill (KSR) comprised of both wheel odometry and lidar-based Visual Odometry (VO). It is shown that for the wheel odometry solution, the final estimate of rover position was within 21 metres of the groundtruth as calculated by a differential GPS receiver, or 0.85% of the total traverse distance. When the star tracker measurements are artificially limited to occurring approximately every 250 metres, the algorithm still performs well, giving a final position error of 75.8 metres or 3.0%. Preliminary results to replace wheel odometry with lidar-based VO for the development a full-dark visual solution are also presented. The lidar-based VO solution is shown to be capable of outperforming wheel odometry, but more work is required to develop methods to handle the variety of terrain conditions encountered.

  16. Videometric head tracker for augmented reality applications

    NASA Astrophysics Data System (ADS)

    Janin, Adam L.; Zikan, Karel; Mizell, David; Banner, Mike; Sowizral, Henry A.

    1995-12-01

    For the past three years, we have been developing augmented reality technology for application to a variety of touch labor tasks in aircraft manufacturing and assembly. The system would be worn by factory workers to provide them with better-quality information for performing their tasks than was previously available. Using a see-through head-mounted display (HMD) whose optics are set at a focal length of about 18 in., the display and its associated head tracking system can be used to superimpose and stabilize graphics on the surface of a work piece. This technology would obviate many expensive marking systems now used in aerospace manufacturing. The most challenging technical issue with respect to factory applications of AR is head position and orientation tracking. It requires high accuracy, long- range tracking in a high-noise environment. The approach we have chosen uses a head- mounted miniature video camera. The user's wearable computer system utilizes the camera to find fiducial markings that have been placed on known coordinates on or near the work piece. The system then computes the user's position and orientation relative to the fiducial marks. It is referred to as a `videometric' head tracker. In this paper, we describe the steps we took and the results we obtained in the process of prototyping our videometric head tracker, beginning with analytical and simulation results, and continuing through the working prototypes.

  17. FERMI/GLAST Integrated Trending and Plotting System Release 5.0

    NASA Technical Reports Server (NTRS)

    Ritter, Sheila; Brumer, Haim; Reitan, Denise

    2012-01-01

    An Integrated Trending and Plotting System (ITPS) is a trending, analysis, and plotting system used by space missions to determine performance and status of spacecraft and its instruments. ITPS supports several NASA mission operational control centers providing engineers, ground controllers, and scientists with access to the entire spacecraft telemetry data archive for the life of the mission, and includes a secure Web component for remote access. FERMI/GLAST ITPS Release 5.0 features include the option to display dates (yyyy/ddd) instead of orbit numbers along orbital Long-Term Trend (LTT) plot axis, the ability to save statistics from daily production plots as image files, and removal of redundant edit/create Input Definition File (IDF) screens. Other features are a fix to address invalid packet lengths, a change in naming convention of image files in order to use in script, the ability to save all ITPS plot images (from Windows or the Web) as GIF or PNG format, the ability to specify ymin and ymax on plots where previously only the desired range could be specified, Web interface capability to plot IDFs that contain out-oforder page and plot numbers, and a fix to change all default file names to show yyyydddhhmmss time stamps instead of hhmmssdddyyyy. A Web interface capability sorts files based on modification date (with newest one at top), and the statistics block can be displayed via a Web interface. Via the Web, users can graphically view the volume of telemetry data from each day contained in the ITPS archive in the Web digest. The ITPS could be also used in nonspace fields that need to plot data or trend data, including financial and banking systems, aviation and transportation systems, healthcare and educational systems, sales and marketing, and housing and construction.

  18. Gamma Large Area Silicon Telescope (GLAST): Applying silicon strip detector technology to the detection of gamma rays in space

    SciTech Connect

    Atwood, W.B.; The GLAST Collaboration

    1993-06-01

    The recent discoveries and excitement generated by space satellite experiment EGRET (presently operating on Compton Gamma Ray Observatory -- CGRO) have prompted an investigation into modern detector technologies for the next generation space based gamma ray telescopes. The GLAST proposal is based on silicon strip detectors as the {open_quotes}technology of choice{close_quotes} for space application: no consumables, no gas volume, robust (versus fragile), long lived, and self triggerable. The GLAST detector basically has two components: a tracking module preceding a calorimeter. The tracking module has planes of crossed strip (x,y) 300 {mu}m pitch silicon detectors coupled to a thin radiator to measure the coordinates of converted electron-positron pairs. The gap between the layers ({approximately}5 cm) provides a lever arm for track fitting resulting in an angular resolution of <0.1{degree} at high energy. The status of this R & D effort is discussed including details on triggering the instrument, the organization of the detector electronics and readout, and work on computer simulations to model this instrument.

  19. Visible-spectrum remote eye tracker for gaze communication

    NASA Astrophysics Data System (ADS)

    Imabuchi, Takashi; Prima, Oky Dicky A.; Kikuchi, Hikaru; Horie, Yusuke; Ito, Hisayoshi

    2015-03-01

    Many approaches have been proposed to create an eye tracker based on visible-spectrum. These efforts provide a possibility to create inexpensive eye tracker capable to operate outdoor. Although the resulted tracking accuracy is acceptable for a visible-spectrum head-mounted eye tracker, there are many limitations of these approaches to create a remote eye tracker. In this study, we propose a high-accuracy remote eye tracker that uses visible-spectrum imaging and several gaze communication interfaces suited to the tracker. The gaze communication interfaces are designed to assist people with motor disability. Our results show that the proposed eye tracker achieved an average accuracy of 0.77° and a frame rate of 28 fps with a personal computer. With a tablet device, the proposed eye tracker achieved an average accuracy of 0.82° and a frame rate of 25 fps. The proposed gaze communication interfaces enable users to type a complete sentence containing eleven Japanese characters in about a minute.

  20. SVT: an online silicon vertex tracker for the CDF upgrade

    SciTech Connect

    Bardi, A.; Belforte, S.; Berryhill, J.; CDF Collaboration

    1997-07-01

    The SVT is an online tracker for the CDF upgrade which will reconstruct 2D tracks using information from the Silicon VerteX detector (SVXII) and Central Outer Tracker (COT). The precision measurement of the track impact parameter will then be used to select and record large samples of B hadrons. We discuss the overall architecture, algorithms, and hardware implementation of the system.

  1. Laser tracker error determination using a network measurement

    NASA Astrophysics Data System (ADS)

    Hughes, Ben; Forbes, Alistair; Lewis, Andrew; Sun, Wenjuan; Veal, Dan; Nasr, Karim

    2011-04-01

    We report on a fast, easily implemented method to determine all the geometrical alignment errors of a laser tracker, to high precision. The technique requires no specialist equipment and can be performed in less than an hour. The technique is based on the determination of parameters of a geometric model of the laser tracker, using measurements of a set of fixed target locations, from multiple locations of the tracker. After fitting of the model parameters to the observed data, the model can be used to perform error correction of the raw laser tracker data or to derive correction parameters in the format of the tracker manufacturer's internal error map. In addition to determination of the model parameters, the method also determines the uncertainties and correlations associated with the parameters. We have tested the technique on a commercial laser tracker in the following way. We disabled the tracker's internal error compensation, and used a five-position, fifteen-target network to estimate all the geometric errors of the instrument. Using the error map generated from this network test, the tracker was able to pass a full performance validation test, conducted according to a recognized specification standard (ASME B89.4.19-2006). We conclude that the error correction determined from the network test is as effective as the manufacturer's own error correction methodologies.

  2. Optimization of the silicon sensors for the CMS tracker

    NASA Astrophysics Data System (ADS)

    Albergo, S.; Angarano, M.; Azzi, P.; Babucci, E.; Bacchetta, N.; Bader, A.; Bagliesi, G.; Basti, A.; Biggeri, U.; Biino, C.; Bilei, G. M.; Bisello, D.; Boemi, D.; Bosi, F.; Borello, L.; Braibant, S.; Breuker, H.; Brunetti, M. T.; Bruzzi, M.; Buffini, A.; Busoni, S.; Candelori, A.; Caner, A.; Castaldi, R.; Castro, A.; Catacchini, E.; Checcucci, B.; Ciampolini, P.; Civinini, C.; Costa, M.; Creanza, D.; D'Alessandro, R.; DeMaria, N.; de Palma, M.; Dell'Orso, R.; Dutta, S.; Favro, G.; Fiore, L.; Focardi, E.; French, M.; Freudenreich, K.; Frey, A.; Friedl, M.; Fürtjes, A.; Giassi, A.; Giorgi, M.; Giraldo, A.; Glessing, W.; Gu, W. H.; Hall, G.; Hammarstrom, R.; Hebbeker, T.; Honkanen, A.; Honma, A.; Hrubec, J.; Huhtinen, M.; Kaminsky, A.; Karimaki, V.; Koenig, St.; Krammer, M.; Lariccia, P.; Lenzi, M.; Loreti, M.; Luebelsmeyer, K.; Lustermann, W.; Mättig, P.; Maggi, G.; Mannelli, M.; Mantovani, G.; Marchioro, A.; Mariotti, C.; Martignon, G.; Mc Evoy, B.; Meschini, M.; Messineo, A.; Migliore, E.; My, S.; Neviani, A.; Paccagnella, A.; Palla, F.; Pandoulas, D.; Papi, A.; Parrini, G.; Passeri, D.; Pernicka, M.; Pieri, M.; Piperov, S.; Potenza, R.; Radicci, V.; Raffaelli, F.; Raymond, M.; Rizzo, F.; Santocchia, A.; Segneri, G.; Selvaggi, G.; Servoli, L.; Sguazzoni, G.; Siedling, R.; Silvestris, L.; Starodumov, A.; Stavitski, I.; Surrow, B.; Tempesta, P.; Tonelli, G.; Tricomi, A.; Tuominiemi, J.; Tuuva, T.; Verdini, P. G.; Viertel, G.; Xie, Z.; Yahong, Li; Watts, S.; Wittmer, B.

    2001-07-01

    The CMS experiment at the LHC will comprise a large silicon strip tracker. This article highlights some of the results obtained in the R&D studies for the optimization of its silicon sensors. Measurements of the capacitances and of the high voltage stability of the devices are presented before and after irradiation to the dose expected after the full lifetime of the tracker.

  3. Instrument Pointing System /IPS/ - Star trackers

    NASA Astrophysics Data System (ADS)

    Doittau, F. X.; Jamet, J. L.; Vite, M.

    An image dissector tube high accuracy star/sun tracker has been designed for the Spacelab Instrument Pointing System recalibration. Stars with up to mv equals plus eight can be acquired and tracked in a 2 x 2 deg field. Accuracy, (noise excluded) is 0.75 arcsec, rss 3 std dev and noise is less than 0.65 arcsec rms for a mv equals plus eight star. Two-star operation is possible without modification and the sun can also be tracked using a special attachment. Three star sensors equip the Instrument Pointing System and each sensor delivers two-axis coordinates of the selected object (star or sun) which is acquired and tracked in its field of view. These coordinates are processed by the Spacelab onboard computer in order to drive properly the motors actuating the experiment package, for aiming at the desired direction.

  4. Mechatronic Prototype of Parabolic Solar Tracker.

    PubMed

    Morón, Carlos; Díaz, Jorge Pablo; Ferrández, Daniel; Ramos, Mari Paz

    2016-01-01

    In the last 30 years numerous attempts have been made to improve the efficiency of the parabolic collectors in the electric power production, although most of the studies have focused on the industrial production of thermoelectric power. This research focuses on the application of this concentrating solar thermal power in the unexplored field of building construction. To that end, a mechatronic prototype of a hybrid paraboloidal and cylindrical-parabolic tracker based on the Arduido technology has been designed. The prototype is able to measure meteorological data autonomously in order to quantify the energy potential of any location. In this way, it is possible to reliably model real commercial equipment behavior before its deployment in buildings and single family houses. PMID:27314359

  5. Mechatronic Prototype of Parabolic Solar Tracker

    PubMed Central

    Morón, Carlos; Díaz, Jorge Pablo; Ferrández, Daniel; Ramos, Mari Paz

    2016-01-01

    In the last 30 years numerous attempts have been made to improve the efficiency of the parabolic collectors in the electric power production, although most of the studies have focused on the industrial production of thermoelectric power. This research focuses on the application of this concentrating solar thermal power in the unexplored field of building construction. To that end, a mechatronic prototype of a hybrid paraboloidal and cylindrical-parabolic tracker based on the Arduido technology has been designed. The prototype is able to measure meteorological data autonomously in order to quantify the energy potential of any location. In this way, it is possible to reliably model real commercial equipment behavior before its deployment in buildings and single family houses. PMID:27314359

  6. Infrared tracker for a portable missile launcher

    SciTech Connect

    Carlson, J.J.

    1993-07-13

    An infrared beam tracker is described for arrangement to a housing that is unitary with a portable missile launcher, comprising: a rotating beam splitter positioned to intercept the infrared beam passing a first portion of the beam through the beam splitter along a first direction and reflecting the remaining portion along a different direction; a first infrared detector for receiving the beam reflected portion from the beam splitter and produce electric signals responsive thereto; a second infrared detector for receiving the beam portion that passes through the beam splitter and providing electric signals responsive thereto; and means interconnected to the first and second infrared detectors and responsive to the electric signals generated by said detectors for determining errors in missile flight direction and communicating course correction information to the missile.

  7. 3D Technology for intelligent trackers

    SciTech Connect

    Lipton, Ronald; /Fermilab

    2010-09-01

    At Super-LHC luminosity it is expected that the standard suite of level 1 triggers for CMS will saturate. Information from the tracker will be needed to reduce trigger rates to satisfy the level 1 bandwidth. Tracking trigger modules which correlate information from closely-spaced sensor layers to form an on-detector momentum filter are being developed by several groups. We report on a trigger module design which utilizes three dimensional integrated circuit technology incorporating chips which are connected both to the top and bottom sensor, providing the ability to filter information locally. A demonstration chip, the VICTR, has been submitted to the Chartered/Tezzaron two-tier 3D run coordinated by Fermilab. We report on the 3D design concept, the status of the VICTR chip and associated sensor integration utilizing oxide bonding.

  8. Generic evaluation tracker database for OTH radar

    NASA Astrophysics Data System (ADS)

    Flanders, Lorraine E.; Hartnett, Michael P.; Vannicola, Vincent C.

    1999-10-01

    This paper provides a real world target and clutter model for evaluation of radar signal processing algorithms. The procedure is given for target and clutter data collection which is then followed by the equalization and superposition method. We show how the model allows one to vary the target signal to clutter noise ratio so that system performance may be assessed over a wide range of target amplitudes, i.e. detection probability versus target signal to noise ratio. Three candidate pre-track algorithms are evaluated and compared using this model as input in conjunction with an advanced tracker algorithm as a post processor. Data used for the model represents airborne traffic operating over the body of water bounded by North, Central, and South America. The processors relate to the deployment of Over the Horizon Radar for drug interdiction. All the components of this work, model as well as the processors, are in software.

  9. Performance of the Microwave Anisotropy Probe AST-201 Star Trackers

    NASA Technical Reports Server (NTRS)

    Ward, David K.; vanBezooijen, Roelof; Bauer, Frank H. (Technical Monitor)

    2002-01-01

    The Microwave Anisotropy Probe (MAP) was launched to create a full-sky map of the cosmic microwave background. MAP incorporates two modified Lockheed Martin AST-201 (Autonomous Star Tracker) star trackers. The AST-201 employs an eight element radiation hardened lens assembly which is used to focus an image on a charge coupled device (CCD). The CCD image is then processed by a star identification algorithm which outputs a three-axis attitude. A CCD-shift algorithm called Time Delayed Integration (TDI) was also included in each star tracker. In order to provide some radiation effect filtering during MAP's three to five phasing loop passes through the Van Allen radiation belts, a simple pixel filtering scheme was implemented, rather than using a more complex, but more robust windowing algorithm. The trackers also include a fiber optic data interface. This paper details the ground testing that was accomplished on the MAP trackers.

  10. A Heavy Flavor Tracker for STAR

    SciTech Connect

    Chasman, C.; Beavis, D.; Debbe, R.; Lee, J.H.; Levine, M.J.; Videbaek, F.; Xu, Z.; Kleinfelder, S.; Li, S.; Cendejas, R.; Huang, H.; Sakai, S.; Whitten, C.; Joseph, J.; Keane, D.; Margetis, S.; Rykov, V.; Zhang, W.M.; Bystersky, M.; Kapitan, J.; Kushpil, V.; Sumbera, M.; Baudot, J.; Hu-Guo, C.; Shabetai, A.; Szelezniak, M.; Winter, M.; Kelsey, J.; Milner, R.; Plesko, M.; Redwine, R.; Simon, F.; Surrow, B.; Van Nieuwenhuizen, G.; Anderssen, E.; Dong, X.; Greiner, L.; Matis, H.S.; Morgan, S.; Ritter, H.G.; Rose, A.; Sichtermann, E.; Singh, R.P.; Stezelberger, T.; Sun, X.; Thomas, J.H.; Tram, V.; Vu, C.; Wieman, H.H.; Xu, N.; Hirsch, A.; Srivastava, B.; Wang, F.; Xie, W.; Bichsel, H.

    2008-02-25

    The STAR Collaboration proposes to construct a state-of-the-art microvertex detector,the Heavy Flavor Tracker (HFT), utilizing active pixel sensors and silicon strip technology. The HFT will significantly extend the physics reach of the STAR experiment for precision measurement of the yields and spectra of particles containing heavy quarks. This will be accomplished through topological identification of D mesons by reconstruction of their displaced decay vertices with a precision of approximately 50 mu m in p+p, d+A, and A+A collisions. The HFT consists of 4 layers of silicon detectors grouped into two sub-systems with different technologies, guaranteeing increasing resolution when tracking from the TPC and the Silicon Strip Detector (SSD) towards the vertex of the collision. The Intermediate Silicon Tracker (IST), consisting of two layers of single-sided strips, is located inside the SSD. Two layers of Silicon Pixel Detector (PIXEL) are inside the IST. The PIXEL detectors have the resolution necessary for a precision measurement of the displaced vertex. The PIXEL detector will use CMOS Active Pixel Sensors (APS), an innovative technology never used before in a collider experiment. The APSsensors are only 50 mu m thick and at a distance of only 2.5 cm from the interaction point. This opens up a new realm of possibilities for physics measurements. In particular, a thin detector (0.28percent radiation length per layer) in STAR makes it possible to do the direct topological reconstruction of open charm hadrons down to very low pT by the identification of the charged daughters of the hadronic decay.

  11. Four years of Fermi LAT flare advocate activity

    NASA Astrophysics Data System (ADS)

    Ciprini, Stefano; Fermi-LAT Collaboration

    2012-12-01

    The Fermi Flare Advocate (also known as Gamma-ray Sky Watcher, FA-GSW) service provides for a daily quicklook analysis and review of the high-energy gamma-ray sky seen by the Fermi Large Area Telescope (LAT). The FA-GSW service communicates alerts for potentially new gamma-ray sources, interesting transients and flares. A weekly digest containing the highlights about the GeV gamma-ray sky is published in the web-based Fermi Sky Blog and email for special events are posted through the LAT multifrequency mailing-list. During the first 4 years of Fermi allsky survey, more than 200 Astronomical Telegrams, several alerts to the TeV Cherenkov telescopes, and target of opportunity to Swift and other observatories have been realized. This increased the rate of simultaneous multi-frequency observing campaigns and the level of international scientific cooperation.

  12. Search for Dark Matter Satellites Using the FERMI-LAT

    SciTech Connect

    Ackermann, M.; Albert, A.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Blandford, R.D.; Bloom, E.D.; Bonamente, E.; Borgland, A.W.; Bottacini, E.; Brandt, T.J.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Burnett, T.H.; Caliandro, G.A.; Cameron, R.A.; /more authors..

    2012-08-16

    Numerical simulations based on the {Lambda}CDM model of cosmology predict a large number of as yet unobserved Galactic dark matter satellites. We report the results of a Large Area Telescope (LAT) search for these satellites via the {gamma}-ray emission expected from the annihilation of weakly interacting massive particle (WIMP) dark matter. Some dark matter satellites are expected to have hard {gamma}-ray spectra, finite angular extents, and a lack of counterparts at other wavelengths. We sought to identify LAT sources with these characteristics, focusing on {gamma}-ray spectra consistent with WIMP annihilation through the b{bar b} channel. We found no viable dark matter satellite candidates using one year of data, and we present a framework for interpreting this result in the context of numerical simulations to constrain the velocity-averaged annihilation cross section for a conventional 100 GeV WIMP annihilating through the b{bar b} channel.

  13. Search for Dark Matter Satellites Using the Fermi-Lat

    NASA Technical Reports Server (NTRS)

    Ackermann, M.; Albert, A.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Burnett, T. H.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Casandjian, J. M.; McEnery, J. E.; Troja, E.

    2012-01-01

    Numerical simulations based on the ACDM model of cosmology predict a large number of as yet unobserved Galactic dark matter satellites. We report the results of a Large Area Telescope (LAT) search for these satellites via the gamma-ray emission expected from the annihilation of weakly interacting massive particle (WIMP) dark matter. Some dark matter satellites are expected to have hard gamma-ray spectra, finite angular extents, and a lack of counterparts at other wavelengths. We sought to identify LAT sources with these characteristics, focusing on gamma-ray spectra consistent with WIMP annihilation through the bb(sup raised bar) channel. We found no viable dark matter satellite candidates using one year of data, and we present a framework for interpreting this result in the context of numerical simulations to constrain the velocity-averaged annihilation cross section for a conventional 100 Ge V WIMP annihilating through the bb(sup raised bar) channel.

  14. Fermi LAT Stacking Analysis of Swift Localized GRBs

    NASA Astrophysics Data System (ADS)

    Ackermann, M.; Ajello, M.; Anderson, B.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Barbiellini, G.; Bastieri, D.; Bellazzini, R.; Bhat, P. N.; Bissaldi, E.; Bonino, R.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caragiulo, M.; Caraveo, P. A.; Cecchi, C.; Charles, E.; Chekhtman, A.; Chiang, J.; Chiaro, G.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Conrad, J.; Cutini, S.; D’Ammando, F.; de Angelis, A.; de Palma, F.; Desiante, R.; Di Venere, L.; Drell, P. S.; Favuzzi, C.; Focke, W. B.; Franckowiak, A.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Giglietto, N.; Giordano, F.; Giroletti, M.; Godfrey, G.; Grenier, I. A.; Grove, J. E.; Guiriec, S.; Hewitt, J. W.; Hill, A. B.; Horan, D.; Jóhannesson, G.; Kocevski, D.; Kouveliotou, C.; Kuss, M.; Larsson, S.; Li, J.; Li, L.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Mayer, M.; Mazziotta, M. N.; McEnery, J. E.; Michelson, P. F.; Mizuno, T.; Monzani, M. E.; Morselli, A.; Murgia, S.; Nemmen, R.; Nuss, E.; Ohno, M.; Ohsugi, T.; Omodei, N.; Orienti, M.; Orlando, E.; Paneque, D.; Perkins, J. S.; Pesce-Rollins, M.; Piron, F.; Pivato, G.; Porter, T. A.; Racusin, J. L.; Rainò, S.; Rando, R.; Razzano, M.; Reimer, A.; Reimer, O.; Schaal, M.; Schulz, A.; Sgrò, C.; Siskind, E. J.; Spada, F.; Spandre, G.; Spinelli, P.; Takahashi, H.; Thayer, J. B.; Tibaldo, L.; Tinivella, M.; Torres, D. F.; Tosti, G.; Troja, E.; Vianello, G.; von Kienlin, A.; Werner, M.; Wood, K. S.

    2016-05-01

    We perform a comprehensive stacking analysis of data collected by the Fermi Large Area Telescope (LAT) of γ-ray bursts (GRBs) localized by the Swift spacecraft, which were not detected by the LAT but which fell within the instrument’s field of view at the time of trigger. We examine a total of 79 GRBs by comparing the observed counts over a range of time intervals to that expected from designated background orbits, as well as by using a joint likelihood technique to model the expected distribution of stacked counts. We find strong evidence for subthreshold emission at MeV to GeV energies using both techniques. This observed excess is detected during intervals that include and exceed the durations typically characterizing the prompt emission observed at keV energies and lasts at least 2700 s after the co-aligned burst trigger. By utilizing a novel cumulative likelihood analysis, we find that although a burst’s prompt γ-ray and afterglow X-ray flux both correlate with the strength of the subthreshold emission, the X-ray afterglow flux measured by Swift’s X-ray Telescope at 11 hr post trigger correlates far more significantly. Overall, the extended nature of the subthreshold emission and its connection to the burst’s afterglow brightness lend further support to the external forward shock origin of the late-time emission detected by the LAT. These results suggest that the extended high-energy emission observed by the LAT may be a relatively common feature but remains undetected in a majority of bursts owing to instrumental threshold effects.

  15. Constraining decaying dark matter with Fermi LAT gamma-rays

    SciTech Connect

    Zhang, Le; Sigl, Günter; Weniger, Christoph; Maccione, Luca; Redondo, Javier E-mail: christoph.weniger@desy.de E-mail: redondo@mppmm.mpg.de

    2010-06-01

    High energy electrons and positrons from decaying dark matter can produce a significant flux of gamma rays by inverse Compton off low energy photons in the interstellar radiation field. This possibility is inevitably related with the dark matter interpretation of the observed PAMELA and FERMI excesses. The aim of this paper is providing a simple and universal method to constrain dark matter models which produce electrons and positrons in their decay by using the Fermi LAT gamma-ray observations in the energy range between 0.5 GeV and 300 GeV. We provide a set of universal response functions that, once convolved with a specific dark matter model produce the desired constraints. Our response functions contain all the astrophysical inputs such as the electron propagation in the galaxy, the dark matter profile, the gamma-ray fluxes of known origin, and the Fermi LAT data. We study the uncertainties in the determination of the response functions and apply them to place constraints on some specific dark matter decay models that can well fit the positron and electron fluxes observed by PAMELA and Fermi LAT. To this end we also take into account prompt radiation from the dark matter decay. We find that with the available data decaying dark matter cannot be excluded as source of the PAMELA positron excess.

  16. Five Years of the Fermi LAT Flare Advocate

    NASA Astrophysics Data System (ADS)

    Carpenter, Bryce; Ojha, R.; Gasparrini, D.; Ciprini, S.; Fermi LAT Collaboration; Fermi LAT Flare Advocates

    2014-01-01

    Since the launch of the Fermi satellite, the Fermi Large Area Telescope (LAT) team has run a program that provides a daily review of the the gamma-ray sky as soon as Fermi LAT data becomes available. The Flare Advocate/Gamma-ray Sky Watcher (FA-GSW) program allows a rapid analysis of the Automatic Science Processing (ASP) products and triggers dedicated followup analyses by several LAT science groups such as those studying Galactic transients, extragalactic sources and new gamma-ray sources. Significant gamma-ray detections also trigger rapid communications to the entire astrophysical community via astronomical telegrams and gamma-ray coordination network notices. The FA-GSW program plays a key role in maximizing the science return from Fermi by increasing the rate of multi-frequency observations of sources in an active gamma-ray state. In the past ~5 years blazar flaring activity of varying strength and duty cycles, gravitationally lensed blazars, flares from Galactic sources (like Nova Delphini and the Crab Nebula), unidentified transients near and off the Galactic plane, and emission from the quiet and flaring Sun, represent the range of detections made. Flare Advocates have published about 250 Astronomical Telegrams and they publish a weekly blog. Timely, extensive multi-frequency campaigns have been organized to follow-up on these phenomena leading to some of Fermi’s most interesting results.

  17. New technologies in the D0 central tracker upgrade

    SciTech Connect

    Lincoln, D.; D0 Collaboration

    1996-06-01

    The D0 collaboration has undertaken an aggressive upgrade of its central tracking system. The existing tracker will be completely removed and replaced by a two Tesla superconducting solenoidal magnet, an 837 000 channel silicon vertex system, and 80 000 channel scintillating fiber tracker, followed by a 7 680 channel central preshower detector and a 16 000 channel forward preshower detector. In this paper the author discusses all of the subsystems of the D0 central tracker upgrade, but will emphasize those aspects which involve new technology: radiation hard scintillating fiber, VLPC`s and extruded scintillating strips.

  18. Status of the D0 fiber tracker and preshower detectors

    SciTech Connect

    Smirnov, Dmitri; ,

    2009-01-01

    In this report we focus on the performance of the D0 central fiber tracker and preshower detectors during the high luminosity p{bar p} collisions at {radical}s = 1.96 GeV delivered by the Tevatron collider at Fermilab (Run IIb). Both fiber tracker and preshower detectors utilize a similar readout system based on high quantum efficiency solid state photo-detectors capable of converting light into electrical signals. We also give a brief description of the D0 detector and the central track trigger, and conclude with a summary on the central tracker performance.

  19. EOS attitude determination and next generation star tracker enhancements

    NASA Technical Reports Server (NTRS)

    Kudva, P.; Throckmorton, A.

    1993-01-01

    The pointing knowledge required for the Earth Observing System (EOS) AM mission is at the limit of the current generation of star trackers, with little margin. Techniques for improving the performance of existing star trackers are explored, with performance sensitivities developed for each alternative. These are extended to define the most significant performance enhancements for a next generation star tracker. Since attitude determination studies tend to be computationally intensive, an approach for using a simpler one degree of freedom formulation is contrasted with a full three degree of freedom formulation. Additionally, covariance analysis results are compared with time domain simulation performance results.

  20. High Energy Astronomy Observatory star tracker search program

    NASA Technical Reports Server (NTRS)

    Weiler, W. J.

    1972-01-01

    The development of a control system to accommodate the scientific payload of the High Energy Astronomy Observatory (HEAO) is discussed. One of the critical elements of the system is the star tracker subsystem, which defines an accurate three-axis attitude reference. A digital computer program has been developed to evaluate the ability of a particular star tracker configuration to meet the requirements for attitude reference at various vehicle orientations. Used in conjuction with an adequate star catalog, the computer program provides information on availability of stars for each tracker and on the ability of the system to maintain three-axis attitude reference throughout a representative sequence of vehicle orientations.

  1. The research on image processing technology of the star tracker

    NASA Astrophysics Data System (ADS)

    Li, Yu-ming; Li, Chun-jiang; Zheng, Ran; Li, Xiao; Yang, Jun

    2014-11-01

    As the core of visual sensitivity via imaging, image processing technology, especially for star tracker, is mainly characterized by such items as image exposure, optimal storage, background estimation, feature correction, target extraction, iteration compensation. This paper firstly summarizes the new research on those items at home and abroad, then, according to star tracker's practical engineering, environment in orbit and lifetime information, shows an architecture about rapid fusion between multiple frame images, which can be used to restrain oversaturation of the effective pixels, which means star tracker can be made more precise, more robust and more stable.

  2. SDC conceptual design: Scintillating fiber outer tracker

    SciTech Connect

    Adams, D.; Baumbaugh, A.; Bird, F.; SDC Collaboration

    1992-01-22

    The authors propose an all-scintillating fiber detector for the purpose of outer tracking for the SDC. The objectives of this tracking system are to: (1) provide a first level trigger for {vert_bar}{eta}{vert_bar} < 2.3 with sharp p{sub T} threshold with the ability to resolve individual beam crossings; (2) provide pattern recognition capability and momentum resolution which complements and extends the capabilities of the inner silicon tracking system; (3) provide three dimensional linkage with outer detection systems including the shower maximum detector, muon detectors, and calorimetry; (4) provide robust tracking and track-triggering at the highest luminosities expected at the SSC. The many attractive features of a fiber tracker include good position resolution, low occupancy, low mass in the active volume, and excellent resistance to radiation damage. An additional important feature, especially at the SSC, is the intrinsically prompt response time of a scintillating fiber. This property is exploited in the construction of a level 1 trigger sensitive to individual beam crossings.

  3. Forward GEM Tracker (FGT) at STAR

    NASA Astrophysics Data System (ADS)

    Surrow, Bernd

    2012-10-01

    As part of our program to understand the internal structure of the proton, we have and will continue mid-rapidity (-1<η<1) W and di-jet measurements in p+p collisions at √s = 500GeV. The ongoing STAR W program is exploring the longitudinal spin contribution of anti-u and anti-d quarks to the proton spin. The gluon spin contribution can be probed through di-jet measurements. The Forward GEM Tracker (FGT) at STAR will enhance the charged sign separation for high pT tracks in the pseudo-rapidity range of 1.0<η<2.0, and therefore allows an extension of W and di-jet measurements at forward pseudo-rapidity. We will present the status of the FGT assembly and completion along with projections for future W and di-jet measurements. We will discuss studies that explore the possibilities of using the FGT to reconstruct jets in the forward direction.

  4. ATLAS silicon microstrip tracker operation and performance

    NASA Astrophysics Data System (ADS)

    Barone, Gaetano

    2013-12-01

    The Semi-Conductor Tracker (SCT) is a silicon strip detector and one of the key precision tracking devices of the Inner Detector of the ATLAS experiment at CERN LHC. The SCT is constructed of 4088 silicon detector modules for a total of 6.3 million channels. Each module is designed, constructed and tested to operate as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two types of structures: one barrel (4 cylinders) and two end-cap systems (9 disks on each). The current results from the successful operation of the SCT Detector at the LHC and its status after three years of operation will be presented. The operation of the detector including an overview of the main issues encountered is reported. The main emphasis is given to the tracking performance of the SCT and the data quality during the >2 years of data taking of proton-proton collision data at 7 TeV (and short periods of heavy ion collisions). The SCT has been fully operational throughout all data taking periods, delivering high quality tracking data.

  5. Performance of the LHCb silicon tracker

    NASA Astrophysics Data System (ADS)

    Cowan, G. A.; the LHCb Silicon Tracker Group

    2013-01-01

    The LHCb detector has been optimised for the search for New Physics in CP violating observables and rare heavy-quark decays at the Large Hadron Collider (LHC). The detector is a single arm forward spectrometer with excellent tracking and particle identification capabilities. The LHCb silicon tracker is constructed from silicon micro-strip detectors with long readout strips. It consists of one four-layer tracking station upstream of the LHCb spectrometer magnet and three stations downstream of the magnet. The detectors have performed extremely well right from the start of LHC operation, permitting the experiment to collect data at instantaneous luminosities well exceeding the design value. In this presentation, an overview of the operational experience from the first two years of data taking at the LHC will be given, with special emphasis on problems encountered. Calibration procedures will be discussed as well as studies of the intrinsic detector efficiency and resolution. First measurements of the observed radiation damage will also be shown.

  6. Operation of the CMS silicon strip tracker

    NASA Astrophysics Data System (ADS)

    Yuri, Gotra; CMS Collaboration

    2011-10-01

    The CMS Silicon Strip Tracker (SST), comprising 9.6 million readout channels from 15148 modules covering an area of about 200 m², needs to be precisely calibrated in order to correctly interpret and reconstruct the events recorded from the detector, ensuring that the SST performance fully meets the physics research program of the CMS experiment. Calibration constants may be derived from promptly reconstructed events as well as from pedestal runs gathered just before the acquisition of physics runs. These calibration procedures were exercised in summer and winter 2009, when the CMS detector was commissioned using cosmic muons and proton-proton collisions at a center-of-mass energies of 900 GeV and 2.36 TeV. During these data taking periods the performance of the SST was carefully studied: the noise of the detector, the data integrity, the signal-to-noise ratio, the hit reconstruction efficiency, the calibration workflows have been all checked for stability and for different conditions, at the module level. The calibration procedures and the detector performance results from recent physics runs are described.

  7. D0 layer 0 innermost layer of silicon microstrip tracker

    SciTech Connect

    Hanagaki, K.; /Fermilab

    2006-01-01

    A new inner layer silicon strip detector has been built and will be installed in the existing silicon microstrip tracker in D0. They report on the motivation, design, and performance of this new detector.

  8. A low-cost, CCD solid state star tracker

    NASA Technical Reports Server (NTRS)

    Chmielowski, M.; Wynne, D.

    1992-01-01

    Applied Research Corporation (ARC) has developed an engineering model of a multi-star CCD-based tracker for space applications requiring radiation hardness, high reliability and low power consumption. The engineering unit compared favorably in functional performance tests to the standard NASA single-star tracker. Characteristics of the ARC star tracker are: field of view = 10 deg x 7.5 deg, sensitivity range of -1 to +5 star magnitude, NEA = 3 in x 3 in, linearity = 5 in x 5 in, and power consumption of 1-3 W (operating mode dependent). The software is upgradable through a remote link. The hardware-limited acquisition rate is 1-5 Hz for stars of +2 to +5 magnitude and 10-30 Hz for -1 to +2 magnitude stars. Mechanical and electrical interfaces are identical to the standard NASA star tracker.

  9. Performance studies of the CMS Strip Tracker before installation

    SciTech Connect

    Adam, W.; et al.

    2009-06-01

    In March 2007 the assembly of the Silicon Strip Tracker was completed at the Tracker Integration Facility at CERN. Nearly 15% of the detector was instrumented using cables, fiber optics, power supplies, and electronics intended for the operation at the LHC. A local chiller was used to circulate the coolant for low temperature operation. In order to understand the efficiency and alignment of the strip tracker modules, a cosmic ray trigger was implemented. From March through July 4.5 million triggers were recorded. This period, referred to as the Sector Test, provided practical experience with the operation of the Tracker, especially safety, data acquisition, power, and cooling systems. This paper describes the performance of the strip system during the Sector Test, which consisted of five distinct periods defined by the coolant temperature. Significant emphasis is placed on comparisons between the data and results from Monte Carlo studies.

  10. Breadboard stellar tracker system test report, volume 2

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Complete data from a test program designed to evaluate the performance of a star tracker, a breadboard tracker system, is presented in tabular form. All data presented was normalized to the pixel dimension of 20 micrometers. Data from determination of maximum spatial noise as it applies to the coarse and fine acquisition modes is presented. Pointing accuracy test data, raw pixel data for the track cycle, and data from equipment related tests is also presented.

  11. HCPV trackers arrangement based on space coordinate transformations

    NASA Astrophysics Data System (ADS)

    Mi, Zhe; Chen, Nuofu; Liu, Hu; Bai, Yiming; Zhang, Xiulan; Chen, Jikun; Wang, Xiangwu

    2014-09-01

    A new pattern of space coordinate system based on sun-tracking surface has been introduced in this paper. The calculation of shadow area between HCPV trackers has been simplified within this kind of coordinate system. The spaces between rows and columns of HCPV arrays can be calculated accurately. Therefore, an appropriate layout of trackers arrangement for a HCPV power plant can be determined and designed by use of this method.

  12. Optical Alignment of the Global Precipitation Measurement (GPM) Star Trackers

    NASA Technical Reports Server (NTRS)

    Hetherington, Samuel; Osgood, Dean; McMann, Joe; Roberts, Viki; Gill, James; Mclean, Kyle

    2013-01-01

    The optical alignment of the star trackers on the Global Precipitation Measurement (GPM) core spacecraft at NASA Goddard Space Flight Center (GSFC) was challenging due to the layout and structural design of the GPM Lower Bus Structure (LBS) in which the star trackers are mounted as well as the presence of the star tracker shades that blocked line-of-sight to the primary star tracker optical references. The initial solution was to negotiate minor changes in the original LBS design to allow for the installation of a removable item of ground support equipment (GSE) that could be installed whenever measurements of the star tracker optical references were needed. However, this GSE could only be used to measure secondary optical reference cube faces not used by the star tracker vendor to obtain the relationship information and matrix transformations necessary to determine star tracker alignment. Unfortunately, due to unexpectedly large orthogonality errors between the measured secondary adjacent cube faces and the lack of cube calibration data, we required a method that could be used to measure the same reference cube faces as originally measured by the vendor. We describe an alternative technique to theodolite auto-collimation for measurement of an optical reference mirror pointing direction when normal incidence measurements are not possible. This technique was used to successfully align the GPM star trackers and has been used on a number of other NASA flight projects. We also discuss alignment theory as well as a GSFC-developed theodolite data analysis package used to analyze angular metrology data.

  13. Space shuttle orbiter vehicle star tracker test program plan

    NASA Technical Reports Server (NTRS)

    Smith, R. A.

    1974-01-01

    The development model test program was written to provide guidance for essential star tracker test support to the Space Shuttle Orbiter Program. The program organization included test equipment preparation, prototype baseline/acceptance tests, prototype total performance tests, and prototype special tests. Test configurations, preparation phase, documentation, scheduling, and manpower requirements are discussed. The test program permits an early evaluation of the tracker's performance prior to completion and testing of the final flight models.

  14. Breadboard stellar tracker system test report, volume 1

    NASA Technical Reports Server (NTRS)

    Kollodge, J. C.; Hubbard, M. W.; Jain, S.; Schons, C. A.

    1981-01-01

    The performance of a star tracker equipped with a focal plane detector was evaluated. The CID board is an array of 256 x 256 pixels which are 20 x 20 micrometers in dimension. The tracker used for test was a breadboard tracker system developed by BASD. Unique acquisition and tracking algorithms are employed to enhance performance. A pattern recognition process is used to test for proper image spread function and to avoid false acquisition on noise. A very linear, high gain, interpixel transfer function is derived for interpolating star position. The lens used in the tracker has an EFL of 100 mm. The tracker has an FOV of 2.93 degrees resulting in a pixel angular subtense of 41.253 arc sec in each axis. The test procedure used for the program presented a star to the tracker in a circular pattern of positions; the pattern was formed by projecting a simulated star through a rotatable deviation wedge. Further tests determined readout noise, Noise Equivalent Displacement during track, and spatial noise during acquisition by taking related data and reducing it.

  15. EMC Diagnosis and Corrective Actions for Silicon Strip Tracker Detectors

    SciTech Connect

    Arteche, F.; Rivetta, C.; /SLAC

    2006-06-06

    The tracker sub-system is one of the five sub-detectors of the Compact Muon Solenoid (CMS) experiment under construction at CERN for the Large Hadron Collider (LHC) accelerator. The tracker subdetector is designed to reconstruct tracks of charged sub-atomic particles generated after collisions. The tracker system processes analogue signals from 10 million channels distributed across 14000 silicon micro-strip detectors. It is designed to process signals of a few nA and digitize them at 40 MHz. The overall sub-detector is embedded in a high particle radiation environment and a magnetic field of 4 Tesla. The evaluation of the electromagnetic immunity of the system is very important to optimize the performance of the tracker sub-detector and the whole CMS experiment. This paper presents the EMC diagnosis of the CMS silicon tracker sub-detector. Immunity tests were performed using the final prototype of the Silicon Tracker End-Caps (TEC) system to estimate the sensitivity of the system to conducted noise, evaluate the weakest areas of the system and take corrective actions before the integration of the overall detector. This paper shows the results of one of those tests, that is the measurement and analysis of the immunity to CM external conducted noise perturbations.

  16. Multi-expert tracking algorithm based on improved compressive tracker

    NASA Astrophysics Data System (ADS)

    Feng, Yachun; Zhang, Hong; Yuan, Ding

    2015-12-01

    Object tracking is a challenging task in computer vision. Most state-of-the-art methods maintain an object model and update the object model by using new examples obtained incoming frames in order to deal with the variation in the appearance. It will inevitably introduce the model drift problem into the object model updating frame-by-frame without any censorship mechanism. In this paper, we adopt a multi-expert tracking framework, which is able to correct the effect of bad updates after they happened such as the bad updates caused by the severe occlusion. Hence, the proposed framework exactly has the ability which a robust tracking method should process. The expert ensemble is constructed of a base tracker and its formal snapshot. The tracking result is produced by the current tracker that is selected by means of a simple loss function. We adopt an improved compressive tracker as the base tracker in our work and modify it to fit the multi-expert framework. The proposed multi-expert tracking algorithm significantly improves the robustness of the base tracker, especially in the scenes with frequent occlusions and illumination variations. Experiments on challenging video sequences with comparisons to several state-of-the-art trackers demonstrate the effectiveness of our method and our tracking algorithm can run at real-time.

  17. HETDEX tracker control system design and implementation

    NASA Astrophysics Data System (ADS)

    Beno, Joseph H.; Hayes, Richard; Leck, Ron; Penney, Charles; Soukup, Ian

    2012-09-01

    To enable the Hobby-Eberly Telescope Dark Energy Experiment, The University of Texas at Austin Center for Electromechanics and McDonald Observatory developed a precision tracker and control system - an 18,000 kg robot to position a 3,100 kg payload within 10 microns of a desired dynamic track. Performance requirements to meet science needs and safety requirements that emerged from detailed Failure Modes and Effects Analysis resulted in a system of 13 precision controlled actuators and 100 additional analog and digital devices (primarily sensors and safety limit switches). Due to this complexity, demanding accuracy requirements, and stringent safety requirements, two independent control systems were developed. First, a versatile and easily configurable centralized control system that links with modeling and simulation tools during the hardware and software design process was deemed essential for normal operation including motion control. A second, parallel, control system, the Hardware Fault Controller (HFC) provides independent monitoring and fault control through a dedicated microcontroller to force a safe, controlled shutdown of the entire system in the event a fault is detected. Motion controls were developed in a Matlab-Simulink simulation environment, and coupled with dSPACE controller hardware. The dSPACE real-time operating system collects sensor information; motor commands are transmitted over a PROFIBUS network to servo amplifiers and drive motor status is received over the same network. To interface the dSPACE controller directly to absolute Heidenhain sensors with EnDat 2.2 protocol, a custom communication board was developed. This paper covers details of operational control software, the HFC, algorithms, tuning, debugging, testing, and lessons learned.

  18. Recent and Future Observations in the X-ray and Gamma-ray Bands: Chandra, Suzaku, GLAST, and NuSTAR

    SciTech Connect

    Madejski, Greg; /SLAC /KIPAC, Menlo Park

    2005-12-02

    This paper presents a brief overview of the accomplishments of the Chandra satellite that are shedding light on the origin of high energy particles in astrophysical sources, with the emphasis on clusters of galaxies. It also discusses the prospects for the new data to be collected with instruments recently launched--such as Suzaku--or those to be deployed in the near future, and this includes GLAST and NuSTAR.

  19. W.K.H. Panofsky Prize in Experimental Particle Physics Lecture: The making of GLAST: Being creative with experimental particle physics

    NASA Astrophysics Data System (ADS)

    Atwood, William

    2012-03-01

    The extension of astrophysical observations to gamma-ray energies requires the utilization of detectors invented and developed for the pursuit of High Energy Particle Physics. GLAST is the result of a close collaboration between the astrophysics and the HEP communities. The exceedingly small signal-to-noise (cosmic rays) ratio coupled with the need for the best angular resolution possible presented a host of problems. How these were successfully met and the resulting instrument and its science are reviewed.

  20. Reciprocal regulation of amino acid import and epigenetic state through Lat1 and EZH2

    PubMed Central

    Dann, Stephen G; Ryskin, Michael; Barsotti, Anthony M; Golas, Jonathon; Shi, Celine; Miranda, Miriam; Hosselet, Christine; Lemon, Luanna; Lucas, Judy; Karnoub, Maha; Wang, Fang; Myers, Jeremy S; Garza, Scott J; Follettie, Maximillian T; Geles, Kenneth G; Klippel, Anke; Rollins, Robert A; Fantin, Valeria R

    2015-01-01

    Lat1 (SLC7A5) is an amino acid transporter often required for tumor cell import of essential amino acids (AA) including Methionine (Met). Met is the obligate precursor of S-adenosylmethionine (SAM), the methyl donor utilized by all methyltransferases including the polycomb repressor complex (PRC2)-specific EZH2. Cell populations sorted for surface Lat1 exhibit activated EZH2, enrichment for Met-cycle intermediates, and aggressive tumor growth in mice. In agreement, EZH2 and Lat1 expression are co-regulated in models of cancer cell differentiation and co-expression is observed at the invasive front of human lung tumors. EZH2 knockdown or small-molecule inhibition leads to de-repression of RXRα resulting in reduced Lat1 expression. Our results describe a Lat1-EZH2 positive feedback loop illustrated by AA depletion or Lat1 knockdown resulting in SAM reduction and concomitant reduction in EZH2 activity. shRNA-mediated knockdown of Lat1 results in tumor growth inhibition and points to Lat1 as a potential therapeutic target. PMID:25979827

  1. Pulsars above 10 GeV: Fermi LAT Observations and Questions

    NASA Technical Reports Server (NTRS)

    Thomson, Dave

    2012-01-01

    The success of the Fermi Large Area Telescope in studying gamma-ray pulsars offers hints about future work above 10 GeV. The infrastructure for discovering pulsars will be similar between LAT and any future telescope. Some of the Fermi LAT results suggest intriguing questions about the future of high-energy pulsar studies.

  2. Annihilation Lines from Dark Matter with the Fermi-LAT

    NASA Astrophysics Data System (ADS)

    Ylinen, Tomi

    2010-06-01

    Dark matter is today one of the most intriguing but so far unresolved issues in physics. Many extensions of the Standard Model of particle physics predict a stable Weakly Interacting Massive Particle (WIMP) that may annihilate directly into two gamma-rays. If the WIMPs are non-relativistic, the gamma-rays from this channel will have an energy equal to the mass of the WIMP. The signature caused by this annihilation is a spectral line, smeared out only by the energy resolution of the detector. The signal would be a ``smoking gun'' for dark matter, since no other astrophysical source should be able to produce it. We present here the preliminary results from the search for a dark matter line on a limited data set from the Fermi Large Area Telescope (LAT), the main instrument onboard the Fermi Gamma-ray Space Telescope, which was successfully launched on June 11, 2008. The Fermi-LAT is a pair-conversion detector for gamma-rays with an energy range from 20 MeV to 300 GeV and has an unprecedented resolution and sensitivity.

  3. Annihilation Lines from Dark Matter with the Fermi-LAT

    SciTech Connect

    Ylinen, Tomi

    2010-06-23

    Dark matter is today one of the most intriguing but so far unresolved issues in physics. Many extensions of the Standard Model of particle physics predict a stable Weakly Interacting Massive Particle (WIMP) that may annihilate directly into two gamma-rays. If the WIMPs are non-relativistic, the gamma-rays from this channel will have an energy equal to the mass of the WIMP. The signature caused by this annihilation is a spectral line, smeared out only by the energy resolution of the detector. The signal would be a ''smoking gun'' for dark matter, since no other astrophysical source should be able to produce it. We present here the preliminary results from the search for a dark matter line on a limited data set from the Fermi Large Area Telescope (LAT), the main instrument onboard the Fermi Gamma-ray Space Telescope, which was successfully launched on June 11, 2008. The Fermi-LAT is a pair-conversion detector for gamma-rays with an energy range from 20 MeV to 300 GeV and has an unprecedented resolution and sensitivity.

  4. Early onset combined immunodeficiency and autoimmunity in patients with loss-of-function mutation in LAT.

    PubMed

    Keller, Baerbel; Zaidman, Irina; Yousefi, O Sascha; Hershkovitz, Dov; Stein, Jerry; Unger, Susanne; Schachtrup, Kristina; Sigvardsson, Mikael; Kuperman, Amir A; Shaag, Avraham; Schamel, Wolfgang W; Elpeleg, Orly; Warnatz, Klaus; Stepensky, Polina

    2016-06-27

    The adapter protein linker for activation of T cells (LAT) is a critical signaling hub connecting T cell antigen receptor triggering to downstream T cell responses. In this study, we describe the first kindred with defective LAT signaling caused by a homozygous mutation in exon 5, leading to a premature stop codon deleting most of the cytoplasmic tail of LAT, including the critical tyrosine residues for signal propagation. The three patients presented from early childhood with combined immunodeficiency and severe autoimmune disease. Unlike in the mouse counterpart, reduced numbers of T cells were present in the patients. Despite the reported nonredundant role of LAT in Ca(2+) mobilization, residual T cells were able to induce Ca(2+) influx and nuclear factor (NF) κB signaling, whereas extracellular signal-regulated kinase (ERK) signaling was completely abolished. This is the first report of a LAT-related disease in humans, manifesting by a progressive combined immune deficiency with severe autoimmune disease. PMID:27242165

  5. New genetic variants of LATS1 detected in urinary bladder and colon cancer

    PubMed Central

    Saadeldin, Mona K.; Shawer, Heba; Mostafa, Ahmed; Kassem, Neemat M.; Amleh, Asma; Siam, Rania

    2015-01-01

    LATS1, the large tumor suppressor 1 gene, encodes for a serine/threonine kinase protein and is implicated in cell cycle progression. LATS1 is down-regulated in various human cancers, such as breast cancer, and astrocytoma. Point mutations in LATS1 were reported in human sarcomas. Additionally, loss of heterozygosity of LATS1 chromosomal region predisposes to breast, ovarian, and cervical tumors. In the current study, we investigated LATS1 genetic variations including single nucleotide polymorphisms (SNPs), in 28 Egyptian patients with either urinary bladder or colon cancers. The LATS1 gene was amplified and sequenced and the expression of LATS1 at the RNA level was assessed in 12 urinary bladder cancer samples. We report, the identification of a total of 29 variants including previously identified SNPs within LATS1 coding and non-coding sequences. A total of 18 variants were novel. Majority of the novel variants, 13, were mapped to intronic sequences and un-translated regions of the gene. Four of the five novel variants located in the coding region of the gene, represented missense mutations within the serine/threonine kinase catalytic domain. Interestingly, LATS1 RNA steady state levels was lost in urinary bladder cancerous tissue harboring four specific SNPs (16045 + 41736 + 34614 + 56177) positioned in the 5′UTR, intron 6, and two silent mutations within exon 4 and exon 8, respectively. This study identifies novel single-base-sequence alterations in the LATS1 gene. These newly identified variants could potentially be used as novel diagnostic or prognostic tools in cancer. PMID:25628642

  6. Human factor requirements of helmet trackers for HMDs

    NASA Astrophysics Data System (ADS)

    Martinsen, Gary L.; Havig, Paul R.; Post, David L.; Reis, George A.; Simpson, Matthew A.

    2003-09-01

    A helmet tracker is a critical element in the path that delivers targeting and other sensor data to the user of a helmet-mounted display (HMD) in a military aircraft. The original purpose of an HMD was to serve as a helmet-mounted sight and provide a means to fully utilize the capabilities of off-boresight munitions. Recently, the role of the HMD has evolved from being strictly a targeting tool to providing detailed flight path and situation awareness information. These changes, however, have placed even greater value on the visual information that is transferred through the helmet tracker to the HMD. Specifically, the timeliness and accuracy of the information, which is of critical importance when the HMD is used as a targeting aid, is of even greater importance when the HMD is used to display flight reference information. This is especially relevant since it has been proposed to build new military aircraft without a physical head-up display (HUD) and display HUD information virtually with an HMD. In this paper, we review the current state of helmet tracker technology with respect to use in military aviation. We also identify the parameters of helmet trackers that offer the greatest risk when using an HMD to provide information beyond targeting data to the user. Finally, we discuss the human factors limitations of helmet tracker systems for delivering both targeting and flight reference information to a military pilot.

  7. Exposure Time Optimization for Highly Dynamic Star Trackers

    PubMed Central

    Wei, Xinguo; Tan, Wei; Li, Jian; Zhang, Guangjun

    2014-01-01

    Under highly dynamic conditions, the star-spots on the image sensor of a star tracker move across many pixels during the exposure time, which will reduce star detection sensitivity and increase star location errors. However, this kind of effect can be compensated well by setting an appropriate exposure time. This paper focuses on how exposure time affects the star tracker under highly dynamic conditions and how to determine the most appropriate exposure time for this case. Firstly, the effect of exposure time on star detection sensitivity is analyzed by establishing the dynamic star-spot imaging model. Then the star location error is deduced based on the error analysis of the sub-pixel centroiding algorithm. Combining these analyses, the effect of exposure time on attitude accuracy is finally determined. Some simulations are carried out to validate these effects, and the results show that there are different optimal exposure times for different angular velocities of a star tracker with a given configuration. In addition, the results of night sky experiments using a real star tracker agree with the simulation results. The summarized regularities in this paper should prove helpful in the system design and dynamic performance evaluation of the highly dynamic star trackers. PMID:24618776

  8. Construction and commissioning of the SuperNEMO detector tracker

    NASA Astrophysics Data System (ADS)

    Cascella, Michele

    2016-07-01

    The SuperNEMO detector will search for neutrinoless double beta decay at the Modane Underground Laboratory; the detector design allows complete topological reconstruction of the decay event enabling excellent levels of background rejection and, in the event of a discovery, the ability to determine the nature of the lepton number violating process. In order to demonstrate the feasibility of the full experiment, we are building a Demonstrator Module containing 7 kg of 82Se, with an expected sensitivity of |mββ | < 0.2 - 0.4 eV after 2.5 yr. The demonstrator tracker is currently being assembled in the UK; the main challenge in the tracker design is the high radiopurity required to limit the background. For this reason the cell wiring is automated and every step of the tracker assembly happens in a clean environment. All components are carefully screened for radiopurity and each section of the tracker, once assembled, is sealed and checked for Radon emanation. We present the detector design, the current status of the construction and present the first results from the surface commissioning of one section of the Demonstrator Module tracker.

  9. Exposure time optimization for highly dynamic star trackers.

    PubMed

    Wei, Xinguo; Tan, Wei; Li, Jian; Zhang, Guangjun

    2014-01-01

    Under highly dynamic conditions, the star-spots on the image sensor of a star tracker move across many pixels during the exposure time, which will reduce star detection sensitivity and increase star location errors. However, this kind of effect can be compensated well by setting an appropriate exposure time. This paper focuses on how exposure time affects the star tracker under highly dynamic conditions and how to determine the most appropriate exposure time for this case. Firstly, the effect of exposure time on star detection sensitivity is analyzed by establishing the dynamic star-spot imaging model. Then the star location error is deduced based on the error analysis of the sub-pixel centroiding algorithm. Combining these analyses, the effect of exposure time on attitude accuracy is finally determined. Some simulations are carried out to validate these effects, and the results show that there are different optimal exposure times for different angular velocities of a star tracker with a given configuration. In addition, the results of night sky experiments using a real star tracker agree with the simulation results. The summarized regularities in this paper should prove helpful in the system design and dynamic performance evaluation of the highly dynamic star trackers. PMID:24618776

  10. Oncogenicity of L-type amino-acid transporter 1 (LAT1) revealed by targeted gene disruption in chicken DT40 cells: LAT1 is a promising molecular target for human cancer therapy

    SciTech Connect

    Ohkawa, Mayumi; Ohno, Yoshiya; Masuko, Kazue; Takeuchi, Akiko; Suda, Kentaro; Kubo, Akihiro; Kawahara, Rieko; Okazaki, Shogo; Tanaka, Toshiyuki; Saya, Hideyuki; Seki, Masayuki; Enomoto, Takemi; Yagi, Hideki; Hashimoto, Yoshiyuki; Masuko, Takashi

    2011-03-25

    Highlights: {yields} We established LAT1 amino-acid transporter-disrupted DT40 cells. {yields} LAT1-disrupted cells showed slow growth and lost the oncogenicity. {yields} siRNA and mAb inhibited human tumor growth in vitro and in vivo. {yields} LAT1 is a promising target molecule for cancer therapy. -- Abstract: L-type amino-acid transporter 1 (LAT1) is the first identified light chain of CD98 molecule, disulfide-linked to a heavy chain of CD98. Following cDNA cloning of chicken full-length LAT1, we have constructed targeting vectors for the disruption of chicken LAT1 gene from genomic DNA of chicken LAT1 consisting of 5.4 kb. We established five homozygous LAT1-disrupted (LAT1{sup -/-}) cell clones, derived from a heterozygous LAT1{sup +/-} clone of DT40 chicken B cell line. Reactivity of anti-chicken CD98hc monoclonal antibody (mAb) with LAT1{sup -/-} DT40 cells was markedly decreased compared with that of wild-type DT40 cells. All LAT1{sup -/-} cells were deficient in L-type amino-acid transporting activity, although alternative-splice variant but not full-length mRNA of LAT1 was detected in these cells. LAT1{sup -/-} DT40 clones showed outstandingly slow growth in liquid culture and decreased colony-formation capacity in soft agar compared with wild-type DT40 cells. Cell-cycle analyses indicated that LAT1{sup -/-} DT40 clones have prolonged cell-cycle phases compared with wild-type or LAT1{sup +/-} DT40 cells. Knockdown of human LAT1 by small interfering RNAs resulted in marked in vitro cell-growth inhibition of human cancer cells, and in vivo tumor growth of HeLa cells in athymic mice was significantly inhibited by anti-human LAT1 mAb. All these results indicate essential roles of LAT1 in the cell proliferation and occurrence of malignant phenotypes and that LAT1 is a promising candidate as a molecular target of human cancer therapy.

  11. Increased neurovirulence and reactivation of the herpes simplex virus type 1 latency-associated transcript (LAT)-negative mutant dLAT2903 with a disrupted LAT miR-H2.

    PubMed

    Jiang, Xianzhi; Brown, Don; Osorio, Nelson; Hsiang, Chinhui; BenMohamed, Lbachir; Wechsler, Steven L

    2016-02-01

    At least six microRNAs (miRNAs) appear to be encoded by the latency-associated transcript (LAT) of herpes simplex virus type 1 (HSV-1). The gene for ICP0, an important immediate early (IE) viral protein, is anti-sense to, and overlaps with, the region of LAT from which miRNA H2 (miR-H2) is derived. We recently reported that a mutant (McK-ΔH2) disrupted for miR-H2 on the wild-type HSV-1 strain McKrae genomic background has increased ICP0 expression, increased neurovirulence, and slightly more rapid reactivation. We report here that HSV-1 mutants deleted for the LAT promoter nonetheless make significant amounts of miR-H2 during lytic tissue culture infection, presumably via readthrough transcription from an upstream promoter. To determine if miR-H2 might also play a role in the HSV-1 latency/reactivation cycle of a LAT-negative mutant, we constructed dLAT-ΔH2, in which miR-H2 is disrupted in dLAT2903 without altering the predicted amino acid sequence of the overlapping ICP0 open reading frame. Similar to McK-ΔH2, dLAT-ΔH2 expressed more ICP0, was more neurovirulent, and had increased reactivation in the mouse TG explant-induced reactivation model of HSV-1 compared with its parental virus. Interestingly, although the increased reactivation of McK-ΔH2 compared with its parental wild-type (wt) virus was subtle and only detected at very early times after explant TG induced reactivation, the increased reactivation of dLAT-ΔH2 compared with its dLAT2903 parental virus appeared more robust and was significantly increased even at late times after induction. These results confirm that miR-H2 plays a role in modulating the HSV-1 reactivation phenotype. PMID:26069184

  12. System and method for calibrating inter-star-tracker misalignments in a stellar inertial attitude determination system

    NASA Technical Reports Server (NTRS)

    Li, Rongsheng (Inventor); Wu, Yeong-Wei Andy (Inventor); Hein, Douglas H. (Inventor)

    2004-01-01

    A method and apparatus for determining star tracker misalignments is disclosed. The method comprises the steps of defining a defining a reference frame for the star tracker assembly according to a boresight of the primary star tracker and a boresight of a second star tracker wherein the boresight of the primary star tracker and a plane spanned by the boresight of the primary star tracker and the boresight of the second star tracker at least partially define a datum for the reference frame for the star tracker assembly; and determining the misalignment of the at least one star tracker as a rotation of the defined reference frame.

  13. Development and Performance Characterization of Colour Star Trackers

    NASA Astrophysics Data System (ADS)

    McVittie, Geoffrey

    Star trackers provide an essential component to a satellite mission requiring high-precision and high-accuracy attitude measurements. A star tracker operates by taking pictures of the celestial sphere and attempting to identify the stars in the image using a combination of the geometric and brightness patterns. The star-positions in the image then determine the attitude of the sensor in the inertial frame. I propose extending the capability of star trackers by including the colour properties of the stars into the star identification process; hence, colour star tracking. Current generation star trackers exist in a variety of forms, with a variety of additional potential designs and operational algorithms proposed in the literature. However, they all share the common trait of using a combination of geometric and monochrome brightness derived patterns to identify stars. Including colour information with the geometric and brightness properties into the identification process represents a new branch in the field of star tracker design. The process of measuring colour also causes a reduction in the amount of light gathered by the sensor, decreasing the number of stars observed. The challenge in colour star tracking becomes establishing that the additional information provided by colour to star patterns is greater than the loss of observable stars due to the measurement process. While superficially brief, accomplishing it touches upon a wide range of topic areas. This includes most research developed for monochromatic star trackers including imaging hardware, optics, noise rejection, parameter estimation, signal detection, data mining, pattern matching, and astronomy. Additionally, using colour necessitates introducing the topics of stellar photometry, spectral filtering, and colour imaging. The approach to colour star tracker development, presented here, considers three aspects to the operation of the technology: colour measurement, star detection, and star pattern

  14. Combinations of 148 navigation stars and the star tracker

    NASA Technical Reports Server (NTRS)

    Duncan, R.

    1980-01-01

    The angular separation of all star combinations for 148 nav star on the onboard software for space transportation system-3 flight and following missions is presented as well as the separation of each pair that satisfies the viewing constraints of using both star trackers simultaneously. Tables show (1) shuttle star catalog 1980 star position in M 1950 coordinates; (2) two star combination of 148 nav stars; and (3) summary of two star-combinations of the star tracker 5 deg filter. These 148 stars present 10,875 combinations. For the star tracker filters of plus or minus 5 deg, there are 875 combinations. Formalhaut (nav star 26) has the best number of combinations, which is 33.

  15. Simulation analysis of dynamic working performance for star trackers.

    PubMed

    Shen, Juan; Zhang, Guangjun; Wei, Xinguo

    2010-12-01

    The elongated imaging track pertaining to a star spot recorded in the image sensor of a star tracker will diffuse over several pixels at a high angular velocity, leading to an inaccurate, even false, attitude value. A computer simulation of the attitude determination from a dynamic star tracker is developed first, based on a dynamic mathematical model of the star-spot imaging and an efficiency validation of the star centroiding algorithm in the dynamic condition. Then major error sources affecting the attitude accuracy in the dynamic condition are analyzed and discussed systematically based on the simulation results. A mathematical model calculating the average star number detected in the field of view is also deduced, using simulation results and signal processing theory, with image trailing ranging from 0 to 20 pixels during exposure. The summarized regularity is helpful in the system design and accuracy evaluation of a star tracker. PMID:21119749

  16. The Reconstruction Software for the Muon Ionization Cooling Experiment Trackers

    SciTech Connect

    Dobbs, A.; Long, K.; Santos, E.; Adey, D.; Hanlet, P.; Heidt, C.

    2014-01-01

    The international Muon Ionisation Cooling Experiment (MICE) is designed to demonstrate the principle of muon ionization cooling, for application to a future Neutrino Factory or Muon Collider. In order to measure the change in emittance, MICE is equipped with a pair of high precision scintillating fibre trackers. The trackers are required to measure a 10% change in emittance to 1% accuracy (giving an overall precision of 0.1%). This paper describes the tracker reconstruction software, as a part of the overall MICE software framework, MAUS. Channel clustering is described, proceeding to the formation of space-points, which are then associated with particle tracks using pattern recognition algorithms. Finally a full custom Kalman track fit is performed, to account for energy loss and multiple scattering. Exemplar results are shown for Monte Carlo data.

  17. Laser tracker TSPI uncertainty quantification via centrifuge trajectory

    NASA Astrophysics Data System (ADS)

    Romero, Edward; Paez, Thomas; Brown, Timothy; Miller, Timothy

    2009-08-01

    Sandia National Laboratories currently utilizes two laser tracking systems to provide time-space-position-information (TSPI) and high speed digital imaging of test units under flight. These laser trackers have been in operation for decades under the premise of theoretical accuracies based on system design and operator estimates. Advances in optical imaging and atmospheric tracking technology have enabled opportunities to provide more precise six degree of freedom measurements from these trackers. Applying these technologies to the laser trackers requires quantified understanding of their current errors and uncertainty. It was well understood that an assortment of variables contributed to laser tracker uncertainty but the magnitude of these contributions was not quantified and documented. A series of experiments was performed at Sandia National Laboratories large centrifuge complex to quantify TSPI uncertainties of Sandia National Laboratories laser tracker III. The centrifuge was used to provide repeatable and economical test unit trajectories of a test-unit to use for TSPI comparison and uncertainty analysis. On a centrifuge, testunits undergo a known trajectory continuously with a known angular velocity. Each revolution may represent an independent test, which may be repeated many times over for magnitudes of data practical for statistical analysis. Previously these tests were performed at Sandia's rocket sled track facility but were found to be costly with challenges in the measurement ground truth TSPI. The centrifuge along with on-board measurement equipment was used to provide known ground truth position of test units. This paper discusses the experimental design and techniques used to arrive at measures of laser tracker error and uncertainty.

  18. Boronophenylalanine, a boron delivery agent for boron neutron capture therapy, is transported by ATB0,+, LAT1 and LAT2

    PubMed Central

    Wongthai, Printip; Hagiwara, Kohei; Miyoshi, Yurika; Wiriyasermkul, Pattama; Wei, Ling; Ohgaki, Ryuichi; Kato, Itsuro; Hamase, Kenji; Nagamori, Shushi; Kanai, Yoshikatsu

    2015-01-01

    The efficacy of boron neutron capture therapy relies on the selective delivery of boron carriers to malignant cells. p-Boronophenylalanine (BPA), a boron delivery agent, has been proposed to be localized to cells through transporter-mediated mechanisms. In this study, we screened aromatic amino acid transporters to identify BPA transporters. Human aromatic amino acid transporters were functionally expressed in Xenopus oocytes and examined for BPA uptake and kinetic parameters. The roles of the transporters in BPA uptake were characterized in cancer cell lines. For the quantitative assessment of BPA uptake, HPLC was used throughout the study. Among aromatic amino acid transporters, ATB0,+, LAT1 and LAT2 were found to transport BPA with Km values of 137.4 ± 11.7, 20.3 ± 0.8 and 88.3 ± 5.6 μM, respectively. Uptake experiments in cancer cell lines revealed that the LAT1 protein amount was the major determinant of BPA uptake at 100 μM, whereas the contribution of ATB0,+ became significant at 1000 μM, accounting for 20–25% of the total BPA uptake in MCF-7 breast cancer cells. ATB0,+, LAT1 and LAT2 transport BPA at affinities comparable with their endogenous substrates, suggesting that they could mediate effective BPA uptake in vivo. The high and low affinities of LAT1 and ATB0,+, respectively, differentiate their roles in BPA uptake. ATB0,+, as well as LAT1, could contribute significantly to the tumor accumulation of BPA at clinical dose. PMID:25580517

  19. Silicon vertex tracker: a fast precise tracking trigger for CDF

    NASA Astrophysics Data System (ADS)

    Ashmanskas, W.; Bardi, A.; Bari, M.; Belforte, S.; Berryhill, J.; Bogdan, M.; Cerri, A.; Clark, A. G.; Chlanchidze, G.; Condorelli, R.; Culbertson, R.; Dell'Orso, M.; Donati, S.; Frisch, H. J.; Galeotti, S.; Giannetti, P.; Glagolev, V.; Leger, A.; Meschi, E.; Morsani, F.; Nakaya, T.; Punzi, G.; Ristori, L.; Sanders, H.; Semenov, A.; Signorelli, G.; Shochet, M.; Speer, T.; Spinella, F.; Wilson, P.; Wu, Xin; Zanetti, A. M.

    2000-06-01

    The Silicon Vertex Tracker (SVT), currently being built for the CDF II experiment, is a hardware device that reconstructs 2-D tracks online using measurements from the Silicon Vertex Detector (SVXII) and the Central Outer Tracker (COT). The precise measurement of the impact parameter of the SVT tracks will allow, for the first time in a hadron collider environment, to trigger on events containing B hadrons that are very important for many studies, such as CP violation in the b sector and searching for new heavy particles decaying to b b¯ . In this report we describe the overall architecture, algorithms and the hardware implementation of the SVT.

  20. Results from the E835 cylindrical scintillating-fiber tracker

    SciTech Connect

    Ambrogiani, M.; Baldini, W.; Bettoni, D.; Calabrese, R.; Luppi, E.; Mussa, R.; Stancari, G. |

    1998-11-01

    A cylindrical 860-channel scintillating-fiber tracker for the measurement of the polar coordinate {theta} has been built for experiment 835 at Fermi National Accelerator Laboratory; it was used during the data-taking period, from October 1996 through September 1997. The high granularity, flexibility and fast response of the scintillating fibers are combined with the high quantum efficiency of the Visible-Light Photon Counters. From this combination, a new kind of detector arises, capable of high-resolution tracking, fast first-level kinematical triggering and single/double-track discrimination. Results of the tracker performance are presented. {copyright} {ital 1998 American Institute of Physics.}

  1. Construction of the tracker for the SuperNEMO experiment

    NASA Astrophysics Data System (ADS)

    Guzowski, P.

    2015-04-01

    The SuperNEMO experiment will search for neutrinoless double β decay with a sensitivity two orders of magnitude greater than its predecessor NEMO-3, achieved through better energy resolution and unprecedented background levels. A Demonstrator module of the detector is currently under construction, due to begin data taking in 2015. A vital component of the detector is the tracker, a wire chamber made from 2,034 cells operating in Geiger mode. This is important for triggering, background discrimination, and measurement of the kinematic properties of the decay. The tracker production procedure and status is presented.

  2. Simulations of silicon vertex tracker for star experiment at RHIC

    SciTech Connect

    Odyniec, G.; Cebra, D.; Christie, W.; Naudet, C.; Schroeder, L.; Wilson, W.; Liko, D.; Cramer, J.; Prindle, D.; Trainor, T.; Braithwaite, W.

    1991-12-31

    The first computer simulations to optimize the Silicon Vertex Tracker (SVT) designed for the STAR experiment at RHIC are presented. The physics goals and the expected complexity of the events at RHIC dictate the design of a tracking system for the STAR experiment. The proposed tracking system will consist of a silicon vertex tracker (SVT) to locate the primary interaction and secondary decay vertices and to improve the momentum resolution, and a time projection chamber (TPC), positioned inside a solenoidal magnet, for continuous tracking.

  3. Simulation of the GEM silicon central tracker using GEANT

    SciTech Connect

    Brooks, M.L.; Kinnison, W.W.

    1994-01-01

    The silicon central tracker of the GEM detector has been simulated using the high energy physics simulations code GEANT. This paper will describe the level of detail of the geometry of the tracker that is in the code, including the silicon detectors themselves as well as all non-sensitive volumes such as support structures; the digitization, or detector response to particles, of the silicon detectors; the coordinate reconstruction from the digitizations, and some of the results of the simulations regarding the detector performance.

  4. Star tracker error analysis: Roll-to-pitch nonorthogonality

    NASA Technical Reports Server (NTRS)

    Corson, R. W.

    1979-01-01

    An error analysis is described on an anomaly isolated in the star tracker software line of sight (LOS) rate test. The LOS rate cosine was found to be greater than one in certain cases which implied that either one or both of the star tracker measured end point unit vectors used to compute the LOS rate cosine had lengths greater than unity. The roll/pitch nonorthogonality matrix in the TNB CL module of the IMU software is examined as the source of error.

  5. Characterization of the Ecosole HCPV tracker and single module inverter

    NASA Astrophysics Data System (ADS)

    Carpanelli, Maurizio; Borelli, Gianni; Verdilio, Daniele; De Nardis, Davide; Migali, Fabrizio; Cancro, Carmine; Graditi, Giorgio

    2015-09-01

    BECAR, the Beghelli group's R&D company, is leading ECOSOLE (Elevated COncentration SOlar Energy), one of the largest European Demonstration projects in solar photovoltaic. ECOSOLE, started in 2012, is focused on the study, design, and realization of new HCPV generator made of high efficiency PV modules equipped with SoG (Silicone on Glass) fresnel lenses and III-V solar cells, and a low cost matched solar tracker with distributed inverters approach. The project also regards the study and demonstration of new high throughput methods for the industrial large scale productions, at very low manufacturing costs. This work reports the description of the characterization of the tracker and single module.

  6. Multiwavelength Spectral Studies Of Fermi-LAT Blazars

    NASA Astrophysics Data System (ADS)

    Joshi, Manasvita; Marscher, A.; Jorstad, S.; Agudo, I.; Larionov, V.; Aller, M.; Gurwell, M.; Lähteenmäki, A.

    2011-01-01

    We present multiwavelength spectral analyses of several Fermi-LAT selected blazars that are part of the Boston University multiwaveband polarization monitoring program. The data for the objects of this study have been compiled from observations with Fermi, RXTE, the VLBA, and various ground-based optical telescopes starting in August 2008. We simulate the dynamic spectral energy distributions (SEDs) within the framework of a multi-zone time-dependent leptonic jet model for blazars, with radiation feedback, in the internal shock scenario. We discuss the intrinsic parameter differences present between the various blazar subclasses of our sample set and the interplay between synchrotron and inverse Compton radiation processes responsible for producing the resultant SEDs. This research was supported in part by NASA through Fermi grants NNX10AO59G, NNX08AV65G, and NNX08AV61G and ADP grant NNX08AJ64G, and by NSF grant AST-0907893.

  7. Multiwavelength Spectral Studies Of Fermi-lat Blazars

    NASA Astrophysics Data System (ADS)

    Joshi, Manasvita; Marscher, A.; Jorstad, S.; Boettcher, M.; Agudo, I.; Larionov, V.; Aller, M.; Gurwell, M.; Lahteenmaki, A.

    2011-09-01

    We present multiwavelength spectral analyses of two Fermi-LAT blazars, OJ 287 and 3C 279, that are part of the Boston University multiwaveband polarization monitoring program. The data have been compiled from observations with Fermi, RXTE, the VLBA, and various ground-based optical and radio telescopes. We simulate the dynamic spectral energy distributions (SEDs) within the framework of a multi-slice, time-dependent leptonic jet model for blazars, with radiation feedback, in the internal shock scenario. We use the physical jet parameters obtained from the VLBA monitoring to guide our modeling efforts. We discuss the role of intrinsic parameters and the interplay between synchrotron and inverse Compton radiation processes responsible for producing the resultant SEDs. This research was supported in part by NASA through Fermi grants NNX10AO59G, NNX08AV65G, and NNX08AV61G and ADP grant NNX08AJ64G, and by NSF grant AST-0907893.

  8. Effect of Redox Balance Alterations on Cellular Localization of LAT and Downstream T-Cell Receptor Signaling Pathways

    PubMed Central

    Gringhuis, Sonja I.; Papendrecht-van der Voort, Ellen A. M.; Leow, Angela; Levarht, E. W. Nivine; Breedveld, Ferdinand C.; Verweij, Cornelis L.

    2002-01-01

    The integral membrane protein linker for activation of T cells (LAT) is a central adapter protein in the T-cell receptor (TCR)-mediated signaling pathways. The cellular localization of LAT is extremely sensitive to intracellular redox balance alterations. Reduced intracellular levels of the antioxidant glutathione (GSH), a hallmark of chronic oxidative stress, resulted in the membrane displacement of LAT, abrogated TCR-mediated signaling and consequently hyporesponsiveness of T lymphocytes. The membrane displacement of LAT is accompanied by a considerable difference in the mobility of LAT upon native and nonreducing denaturing polyacrylamide gel electrophoresis analysis, a finding indicative of a conformational change. Targeted mutation of redox-sensitive cysteine residues within LAT created LAT mutants which remain membrane anchored under conditions of chronic oxidative stress. The expression of redox-insensitive LAT mutants allows for restoration of TCR-mediated signal transduction, whereas CD28-mediated signaling pathways remained impaired. These results are indicative that the membrane displacement of LAT as a result of redox balance alterations is a consequence of a conformational change interfering with the insertion of LAT into the plasma membrane. Conclusively, the data suggest a role for LAT as a crucial intermediate in the sensitivity of TCR signaling and hence T lymphocytes toward chronic oxidative stress. PMID:11756537

  9. Cerebral cortex hyperthyroidism of newborn mct8-deficient mice transiently suppressed by lat2 inactivation.

    PubMed

    Núñez, Bárbara; Martínez de Mena, Raquel; Obregon, Maria Jesus; Font-Llitjós, Mariona; Nunes, Virginia; Palacín, Manuel; Dumitrescu, Alexandra M; Morte, Beatriz; Bernal, Juan

    2014-01-01

    Thyroid hormone entry into cells is facilitated by transmembrane transporters. Mutations of the specific thyroid hormone transporter, MCT8 (Monocarboxylate Transporter 8, SLC16A2) cause an X-linked syndrome of profound neurological impairment and altered thyroid function known as the Allan-Herndon-Dudley syndrome. MCT8 deficiency presumably results in failure of thyroid hormone to reach the neural target cells in adequate amounts to sustain normal brain development. However during the perinatal period the absence of Mct8 in mice induces a state of cerebral cortex hyperthyroidism, indicating increased brain access and/or retention of thyroid hormone. The contribution of other transporters to thyroid hormone metabolism and action, especially in the context of MCT8 deficiency is not clear. We have analyzed the role of the heterodimeric aminoacid transporter Lat2 (Slc7a8), in the presence or absence of Mct8, on thyroid hormone concentrations and on expression of thyroid hormone-dependent cerebral cortex genes. To this end we generated Lat2-/-, and Mct8-/yLat2-/- mice, to compare with wild type and Mct8-/y mice during postnatal development. As described previously the single Mct8 KO neonates had a transient increase of 3,5,3'-triiodothyronine concentration and expression of thyroid hormone target genes in the cerebral cortex. Strikingly the absence of Lat2 in the double Mct8Lat2 KO prevented the effect of Mct8 inactivation in newborns. The Lat2 effect was not observed from postnatal day 5 onwards. On postnatal day 21 the Mct8 KO displayed the typical pattern of thyroid hormone concentrations in plasma, decreased cortex 3,5,3'-triiodothyronine concentration and Hr expression, and concomitant Lat2 inactivation produced little to no modifications. As Lat2 is expressed in neurons and in the choroid plexus, the results support a role for Lat2 in the supply of thyroid hormone to the cerebral cortex during early postnatal development. PMID:24819605

  10. Underexpression of LATS1 TSG in colorectal cancer is associated with promoter hypermethylation

    PubMed Central

    Wierzbicki, Piotr M; Adrych, Krystian; Kartanowicz, Dorota; Stanislawowski, Marcin; Kowalczyk, Anna; Godlewski, Janusz; Skwierz-Bogdanska, Iwona; Celinski, Krzysztof; Gach, Tomasz; Kulig, Jan; Korybalski, Bartlomiej; Kmiec, Zbigniew

    2013-01-01

    AIM: To investigate large tumor suppressor 1 (LATS1) expression, promoter hypermethylation, and microsatellite instability in colorectal cancer (CRC). METHODS: RNA was isolated from tumor tissue of 142 CRC patients and 40 colon mucosal biopsies of healthy controls. After reverse transcription, quantitative polymerase chain reaction (PCR) was performed, and LATS1 expression was normalized to expression of the ACTB and RPL32 housekeeping genes. To analyze hypermethylation, genomic DNA was isolated from 44 tumor CRC biopsies, and methylation-specific PCR was performed. Microsatellite instability (MSI) status was checked with PCR using BAT26, BAT25, and BAT40 markers in the genomic DNA of 84 CRC patients, followed by denaturing gel electrophoresis. RESULTS: Decreased LATS1 expression was found in 127/142 (89.4%) CRC cases with the average ratio of the LATS1 level 10.33 ± 32.64 in CRC patients vs 32.85 ± 33.56 in healthy controls. The lowest expression was found in Dukes’ B stage tumors and G1 (well-differentiated) cells. Hypermethylation of the LATS1 promoter was present in 25/44 (57%) CRC cases analyzed. LATS1 promoter hypermethylation was strongly associated with decreased gene expression; methylated cases showed 162× lower expression of LATS1 than unmethylated cases. Although high-grade MSI (mutation in all three markers) was found in 14/84 (17%) cases and low-grade MSI (mutation in 1-2 markers) was found in 30/84 (36%) cases, we found no association with LATS1 expression. CONCLUSION: Decreased expression of LATS1 in CRC was associated with promoter hypermethylation, but not MSI status. Such reduced expression may promote progression of CRC. PMID:23885148

  11. Search for Spatially Extended Fermi-LAT Sources Using Two Years of Data

    SciTech Connect

    Lande, Joshua; Ackermann, Markus; Allafort, Alice; Ballet, Jean; Bechtol, Keith; Burnett, Toby; Cohen-Tanugi, Johann; Drlica-Wagner, Alex; Funk, Stefan; Giordano, Francesco; Grondin, Marie-Helene; Kerr, Matthew; Lemoine-Goumard, Marianne

    2012-07-13

    Spatial extension is an important characteristic for correctly associating {gamma}-ray-emitting sources with their counterparts at other wavelengths and for obtaining an unbiased model of their spectra. We present a new method for quantifying the spatial extension of sources detected by the Large Area Telescope (LAT), the primary science instrument on the Fermi Gamma-ray Space Telescope (Fermi). We perform a series of Monte Carlo simulations to validate this tool and calculate the LAT threshold for detecting the spatial extension of sources. We then test all sources in the second Fermi -LAT catalog (2FGL) for extension. We report the detection of seven new spatially extended sources.

  12. Aberrant large tumor suppressor 2 (LATS2) gene expression correlates with EGFR mutation and survival in lung adenocarcinomas

    PubMed Central

    Luo, Susan Y.; Sit, Ko-Yung; Sihoe, Alan D.L.; Suen, Wai-Sing; Au, Wing-Kuk; Tang, Ximing; Ma, Edmond S.K.; Chan, Wai-Kong; Wistuba, Ignacio I.; Minna, John D.; Tsao, George S.W.; Lam, David C.L.

    2015-01-01

    Background Large tumor suppressor 2 (LATS2) gene is a putative tumor suppressor gene with potential roles in regulation of cell proliferation and apoptosis in lung cancer. The aim of this study is to explore the association of aberrant LATS2 expression with EGFR mutation and survival in lung adenocarcinoma (AD), and the effects of LATS2 silencing in both lung AD cell lines. Methods LATS2 mRNA and protein expression in resected lung AD were correlated with demographic characteristics, EGFR mutation and survival. LATS2-specific siRNA was transfected into four EGFR wild-type (WT) and three EGFR mutant AD cell lines and the changes in LATS2 expression and relevant signaling molecules before and after LATS2 knockdown were assayed. Results Fifty resected lung AD were included (M:F = 23:27, smokers:non-smokers = 19:31, EGFR mutant:wild-type = 21:29) with LATS2 mRNA levels showed no significant difference between gender, age, smoking and pathological stages while LATS2 immunohistochemical staining on an independent set of 79 lung AD showed similar trend. LATS2 mRNA level was found to be a significant independent predictor for survival status (disease-free survival RR = 0.217; p = 0.003; Overall survival RR = 0.238; p = 0.036). siRNA-mediated suppression of LATS2 expression resulted in augmentation of ERK phosphorylation in EGFR wild-type AD cell lines with high basal LATS2 expression, discriminatory modulation of Akt signaling between EGFR wild-type and mutant cells, and induction of p53 accumulation in AD cell lines with low baseline p53 levels. Conclusions LATS2 expression level is predictive of survival in patients with resected lung AD. LATS2 may modulate and contribute to tumor growth via different signaling pathways in EGFR mutant and wild-type tumors. PMID:24976335

  13. Using Tracker as a Pedagogical Tool for Understanding Projectile Motion

    ERIC Educational Resources Information Center

    Wee, Loo Kang; Chew, Charles; Goh, Giam Hwee; Tan, Samuel; Lee, Tat Leong

    2012-01-01

    This article reports on the use of Tracker as a pedagogical tool in the effective learning and teaching of projectile motion in physics. When a computer model building learning process is supported and driven by video analysis data, this free Open Source Physics tool can provide opportunities for students to engage in active enquiry-based…

  14. Upgrading the ATLAS barrel tracker for the super-LHC

    NASA Astrophysics Data System (ADS)

    Bates, Richard L.; ATLAS ID Collaboration

    2009-08-01

    It has been proposed to increase the luminosity of the large hadron collider (LHC) at CERN by an order of magnitude, with the upgraded machine dubbed super-LHC. The ATLAS experiment will require a new tracker for this high-luminosity operation due to radiation damage and event density. In order to cope with the order of magnitude increase in pile-up backgrounds at the higher luminosity, an all-silicon tracker is being designed. The new strip detector will use significantly shorter strips than the current silicon tracker in order to minimize the occupancy. As the increased luminosity will mean a corresponding increase in radiation dose, a new generation of extremely radiation-hard silicon detectors is required. An R&D program is underway to develop silicon sensors with sufficient radiation hardness. New front-end electronics and readout systems are being designed to cope with the higher data rates. The challenges facing the sensors and the cooling and mechanical support will be discussed. A possible tracker layout will be described.

  15. Highly integrated near-to-eye display and gaze tracker

    NASA Astrophysics Data System (ADS)

    Järvenpää, Toni; Äyräs, Pekka

    2010-05-01

    We have developed a Near-to-Eye Display (NED) technology based on diffractive optics. Thin and highly transparent plastic light guides enable a light-weight and ergonomic see-through NED design. We have previously reported of a compact NED with an integrated gaze tracker. Eye gaze tracker can detect the user's focus point in the displayed image. We have now made advances to further increase the level of integration as well as to enable the optical see-through. Originally, three separate light guides were used: two for the display (red, green/blue) and one for infrared light of the gaze tracker. To reduce weight and the system complexity, a shared light guide is now used for transmitting red (~630 nm, display) and infrared (~850 nm, gaze tracker) wavelengths. In addition, shared output gratings are used for outcoupling the light. Light guide plates have been characterized by measuring their modulation transfer functions. Measurements show that the deterioration of the NED's resolution, caused by the light guides, is reduced with improved manufacturing techniques. Also, it has been verified that the additional gratings for infrared (light in-coupling and expansion areas) do not have a notable effect on the display resolution.

  16. The CDF II eXtremely fast tracker upgrade

    SciTech Connect

    Abulencia, A.; Azzurri, P.; Cochran, E.; Dittmann, J.; Donati, S.; Efron, J.; Erbacher, R.; Errede, D.; Fedorko, I.; Flanagan, G.; Forrest, R.; /Illinois U., Urbana /INFN, Pisa /Pisa U. /Ohio State U. /Baylor U. /UC, Davis /Athens Natl. Capodistrian U. /Purdue U. /Fermilab

    2006-09-01

    The CDF II Extremely Fast Tracker is the trigger track processor which reconstructs charged particle tracks in the transverse plane of the CDF II central outer tracking chamber. The system is now being upgraded to perform a three dimensional track reconstruction. A review of the upgrade is presented here.

  17. Star tracker operation in a high density proton field

    NASA Technical Reports Server (NTRS)

    Miklus, Kenneth J.; Kissh, Frank; Flynn, David J.

    1993-01-01

    Algorithms that reject transient signals due to proton effects on charge coupled device (CCD) sensors have been implemented in the HDOS ASTRA-l Star Trackers to be flown on the TOPEX mission scheduled for launch in July 1992. A unique technique for simulating a proton-rich environment to test trackers is described, as well as the test results obtained. Solar flares or an orbit that passes through the South Atlantic Anomaly can subject the vehicle to very high proton flux levels. There are three ways in which spurious proton generated signals can impact tracker performance: the many false signals can prevent or extend the time to acquire a star; a proton-generated signal can compromise the accuracy of the star's reported magnitude and position; and the tracked star can be lost, requiring reacquisition. Tests simulating a proton-rich environment were performed on two ASTRA-1 Star Trackers utilizing these new algorithms. There were no false acquisitions, no lost stars, and a significant reduction in reported position errors due to these improvements.

  18. CMS tracker performance and readiness for LHC Run II

    NASA Astrophysics Data System (ADS)

    Viliani, L.

    2016-07-01

    The CMS tracker performance during LHC Run I is reviewed. The latest results of both pixel and strip detectors following the first LHC Long Shutdown (LS1) are then presented. Results from detector calibration and commissioning, together with a description of operations and repairs done during LS1, will be shown.

  19. Using "Tracker" to Prove the Simple Harmonic Motion Equation

    ERIC Educational Resources Information Center

    Kinchin, John

    2016-01-01

    Simple harmonic motion (SHM) is a common topic for many students to study. Using the free, though versatile, motion tracking software; "Tracker", we can extend the students experience and show that the general equation for SHM does lead to the correct period of a simple pendulum.

  20. Using Tracker to prove the simple harmonic motion equation

    NASA Astrophysics Data System (ADS)

    Kinchin, John

    2016-09-01

    Simple harmonic motion (SHM) is a common topic for many students to study. Using the free, though versatile, motion tracking software; Tracker, we can extend the students experience and show that the general equation for SHM does lead to the correct period of a simple pendulum.

  1. Evaluating YieldTracker forecast for maize in western Kansas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We seek to predict in-season land productivity to guide irrigation management decisions designed to optimize water utilization in the Ogallala Aquifer region. YieldTracker is a mathematical model that simulates growth and yield of graminoid crops using weather and leaf area index (LAI) as inputs, wh...

  2. The barrel modules of the ATLAS semiconductor tracker

    NASA Astrophysics Data System (ADS)

    Abdesselam, A.; Akimoto, T.; Allport, P. P.; Alonso, J.; Anderson, B.; Andricek, L.; Anghinolfi, F.; Apsimon, R. J.; Barbier, G.; Barr, A. J.; Batchelor, L. E.; Bates, R. L.; Batley, J. R.; Beck, G. A.; Bell, P. J.; Belymam, A.; Bernabeu, J.; Bethke, S.; Bizzell, J. P.; Bohm, J.; Brenner, R.; Brodbeck, T. J.; Broklova, Z.; Broz, J.; Bruckman De Renstrom, P.; Buttar, C. M.; Butterworth, J. M.; Carpentieri, C.; Carter, A. A.; Carter, J. R.; Charlton, D. G.; Cheplakov, A.; Chesi, E.; Chilingarov, A.; Chouridou, S.; Chu, M. L.; Cindro, V.; Ciocio, A.; Civera, J. V.; Clark, A.; Coe, P.; Colijn, A.-P.; Cornelissen, T.; Cosgrove, D. P.; Costa, M. J.; Dabrowski, W.; Dalmau, J.; Danielsen, K. M.; Dawson, I.; Demirkoz, B.; Dervan, P.; Dolezal, Z.; Donega, M.; D'Onofrio, M.; Dorholt, O.; Dowell, J. D.; Drasal, Z.; Duerdoth, I. P.; Dwuznik, M.; Eckert, S.; Ekelof, T.; Eklund, L.; Escobar, C.; Fadeyev, V.; Feld, L.; Ferrari, P.; Ferrere, D.; Fiorini, L.; Fortin, R.; Foster, J. M.; Fox, H.; Fraser, T. J.; Freestone, J.; French, R.; Fuster, J.; Gadomski, S.; Gallop, B. J.; García, C.; Garcia-Navarro, J. E.; Gibson, M. D.; Gibson, S.; Gilchriese, M. G. D.; Godlewski, J.; Gonzalez-Sevilla, S.; Goodrick, M. J.; Gorisek, A.; Gornicki, E.; Greenall, A.; Grigson, C.; Grillo, A. A.; Grosse-Knetter, J.; Haber, C.; Hara, K.; Hartjes, F. G.; Hauff, D.; Hawes, B. M.; Haywood, S. J.; Hessey, N. P.; Hicheur, A.; Hill, J. C.; Hollins, T. I.; Holt, R.; Howell, D. F.; Hughes, G.; Huse, T.; Ibbotson, M.; Ikegami, Y.; Issever, C.; Jackson, J. N.; Jakobs, K.; Jarron, P.; Johansen, L. G.; Jones, T. J.; Jones, T. W.; de Jong, P.; Joos, D.; Jovanovic, P.; Kachiguine, S.; Kaplon, J.; Kato, Y.; Ketterer, C.; Kobayashi, H.; Kodys, P.; Koffeman, E.; Kohout, Z.; Kohriki, T.; Kondo, T.; Koperny, S.; Kramberger, G.; Kubik, P.; Kudlaty, J.; Kuwano, T.; Lacasta, C.; LaMarra, D.; Lane, J. B.; Lee, S.-C.; Lester, C. G.; Limper, M.; Lindsay, S.; Llatas, M. C.; Loebinger, F. K.; Lozano, M.; Ludwig, I.; Ludwig, J.; Lutz, G.; Lys, J.; Maassen, M.; Macina, D.; Macpherson, A.; MacWaters, C.; McMahon, S. J.; McMahon, T. J.; Magrath, C. A.; Malecki, P.; Mandić, I.; Mangin-Brinet, M.; Martí-García, S.; Martinez-Mckinney, G. F. M.; Matheson, J. M. C.; Matson, R. M.; Meinhardt, J.; Mikulec, B.; Mikuž, M.; Minagawa, M.; Mistry, J.; Mitsou, V.; Modesto, P.; Moëd, S.; Mohn, B.; Moorhead, G.; Morin, J.; Morris, J.; Morrissey, M.; Moser, H.-G.; Muijs, A. J. M.; Murray, W. J.; Nagai, K.; Nakamura, K.; Nakamura, Y.; Nakano, I.; Nichols, A.; Nicholson, R.; Nickerson, R. B.; Nisius, R.; O'Shea, V.; Oye, O. K.; Palmer, M. J.; Parker, M. A.; Parzefall, U.; Pater, J. R.; Peeters, S. J. M.; Pellegrini, G.; Pernegger, H.; Perrin, E.; Phillips, A.; Phillips, P. W.; Poltorak, K.; Pospisil, S.; Postranecky, M.; Pritchard, T.; Rafi, J. M.; Ratoff, P. N.; Reznicek, P.; Richter, R. H.; Robinson, D.; Roe, S.; Rosenbaum, F.; Rudge, A.; Runge, K.; Sadrozinski, H. F. W.; Sandaker, H.; Saxon, D. H.; Schieck, J.; Sedlak, K.; Seiden, A.; Sengoku, H.; Sfyrla, A.; Shimma, S.; Smith, K. M.; Smith, N. A.; Snow, S. W.; Solar, M.; Solberg, A.; Sopko, B.; Sospedra, L.; Spencer, E.; Stanecka, E.; Stapnes, S.; Stastny, J.; Stodulski, M.; Stugu, B.; Szczygiel, R.; Tanaka, R.; Tappern, G.; Taylor, G.; Teng, P. K.; Terada, S.; Thompson, R. J.; Titov, M.; Toczek, B.; Tovey, D. R.; Tricoli, A.; Turala, M.; Turner, P. R.; Tyndel, M.; Ullán, M.; Unno, Y.; Van der Kraaij, E.; van Vulpen, I.; Viehhauser, G.; Villani, E. G.; Vorobel, V.; Vos, M.; Wallny, R.; Warren, M. R. M.; Wastie, R. L.; Weber, M.; Weidberg, A. R.; Weilhammer, P.; Wells, P. S.; Wilder, M.; Wilhelm, I.; Wilson, J. A.; Wolter, M.

    2006-12-01

    This paper describes the silicon microstrip modules in the barrel section of the SemiConductor Tracker (SCT) of the ATLAS experiment at the CERN Large Hadron Collider (LHC). The module requirements, components and assembly techniques are given, as well as first results of the module performance on the fully assembled barrels that make up the detector being installed in the ATLAS experiment.

  3. The development of a charge-coupled device tracker for spacecraft

    NASA Technical Reports Server (NTRS)

    Dennison, E. W.; Stanton, R. H.; Shimada, K.

    1987-01-01

    Charge-coupled device (CCD) optical sensors have made it possible to construct high performance star and target trackers for spacecraft. The Advanced Star and Target Reference Orbital Sensor (ASTROS) trackers have been developed by JPL for the Shuttle-based astronomical flight Astro-1 and the Mariner Mark II (MMII) spacecraft. For the Shuttle application the tracker will provide the data for high precision instrument pointing and for the MMII application the tracker will provide stellar and extended target tracking data for flyby and rendezvous navigation. The specifications, architecture, and testing program for these trackers will be described. Laboratory measurements have demonstrated that these trackers can be very effective. The versatility and flexibility of the ASTROS type trackers will permit adaptation to a variety of navigation and guidance applications. These trackers represent one of the technologically advanced components that will be used in the development of the next generation of spacecraft.

  4. Opportunity Science Using the Juno Magnetometer Investigation Star Trackers

    NASA Astrophysics Data System (ADS)

    Joergensen, J. L.; Connerney, J. E.; Bang, A. M.; Denver, T.; Oliversen, R. J.; Benn, M.; Lawton, P.

    2013-12-01

    The magnetometer experiment onboard Juno is equipped with four non-magnetic star tracker camera heads, two of which reside on each of the magnetometer sensor optical benches. These are located 10 and 12 m from the spacecraft body at the end of one of the three solar panel wings. The star tracker, collectively referred to as the Advanced Stellar Compass (ASC), provides high accuracy attitude information for the magnetometer sensors throughout science operations. The star tracker camera heads are pointed +/- 13 deg off the spin vector, in the anti-sun direction, imaging a 13 x 20 deg field of view every ¼ second as Juno rotates at 1 or 2 rpm. The ASC is a fully autonomous star tracker, producing a time series of attitude quaternions for each camera head, utilizing a suite of internal support functions. These include imaging capabilities, autonomous object tracking, automatic dark-sky monitoring, and related capabilities; these internal functions may be accessed via telecommand. During Juno's cruise phase, this capability can be tapped to provide unique science and engineering data available along the Juno trajectory. We present a few examples of the JUNO ASC opportunity science here. As the Juno spacecraft approached the Earth-Moon system for the close encounter with the Earth on October 9, 2013, one of the ASC camera heads obtained imagery of the Earth-Moon system while the other three remained in full science (attitude determination) operation. This enabled the first movie of the Earth and Moon obtained by a spacecraft flying past the Earth in gravity assist. We also use the many artificial satellites in orbit about the Earth as calibration targets for the autonomous asteroid detection system inherent to the ASC autonomous star tracker. We shall also profile the zodiacal dust disk, using the interstellar image data, and present the outlook for small asteroid body detection and distribution being performed during Juno's passage from Earth flyby to Jovian orbit

  5. Structure-based ligand discovery for the Large-neutral Amino Acid Transporter 1, LAT-1.

    PubMed

    Geier, Ethan G; Schlessinger, Avner; Fan, Hao; Gable, Jonathan E; Irwin, John J; Sali, Andrej; Giacomini, Kathleen M

    2013-04-01

    The Large-neutral Amino Acid Transporter 1 (LAT-1)--a sodium-independent exchanger of amino acids, thyroid hormones, and prescription drugs--is highly expressed in the blood-brain barrier and various types of cancer. LAT-1 plays an important role in cancer development as well as in mediating drug and nutrient delivery across the blood-brain barrier, making it a key drug target. Here, we identify four LAT-1 ligands, including one chemically novel substrate, by comparative modeling, virtual screening, and experimental validation. These results may rationalize the enhanced brain permeability of two drugs, including the anticancer agent acivicin. Finally, two of our hits inhibited proliferation of a cancer cell line by distinct mechanisms, providing useful chemical tools to characterize the role of LAT-1 in cancer metabolism. PMID:23509259

  6. Structure-based ligand discovery for the Large-neutral Amino Acid Transporter 1, LAT-1

    PubMed Central

    Geier, Ethan G.; Schlessinger, Avner; Fan, Hao; Gable, Jonathan E.; Irwin, John J.; Sali, Andrej; Giacomini, Kathleen M.

    2013-01-01

    The Large-neutral Amino Acid Transporter 1 (LAT-1)—a sodium-independent exchanger of amino acids, thyroid hormones, and prescription drugs—is highly expressed in the blood–brain barrier and various types of cancer. LAT-1 plays an important role in cancer development as well as in mediating drug and nutrient delivery across the blood–brain barrier, making it a key drug target. Here, we identify four LAT-1 ligands, including one chemically novel substrate, by comparative modeling, virtual screening, and experimental validation. These results may rationalize the enhanced brain permeability of two drugs, including the anticancer agent acivicin. Finally, two of our hits inhibited proliferation of a cancer cell line by distinct mechanisms, providing useful chemical tools to characterize the role of LAT-1 in cancer metabolism. PMID:23509259

  7. Fermi-LAT Gamma-ray Bursts and Insight from Swift

    NASA Technical Reports Server (NTRS)

    Racusin, Judith L.

    2011-01-01

    A new revolution in GRB observation and theory has begun over the last 3 years since the launch of the Fermi gamma-ray space telescope. The new window into high energy gamma-rays opened by the Fermi-LAT is providing insight into prompt emission mechanisms and possibly also afterglow physics. The LAT detected GRBs appear to be a new unique subset of extremely energetic and bright bursts. In this talk I will discuss the context and recent discoveries from these LAT GRBs and the large database of broadband observations collected by Swift over the last 7 years and how through comparisons between the Swift, GBM, and LAT GRB samples, we can learn about the unique characteristics and relationships between each population.

  8. LATS1 phosphorylates forkhead L2 and regulates its transcriptional activity.

    PubMed

    Pisarska, Margareta D; Kuo, Fang-Ting; Bentsi-Barnes, Ikuko K; Khan, Salma; Barlow, Gillian M

    2010-07-01

    Forkhead L2 (FOXL2) is expressed in the ovary and acts as a transcriptional repressor of the steroidogenic acute regulatory (StAR) gene, a marker of granulosa cell differentiation. Human FOXL2 mutations that produce truncated proteins lacking the COOH terminus result in blepharophimosis/ptosis/epicanthus inversus (BPES) syndrome type I, which is associated with premature ovarian failure (POF). In this study, we investigated whether FOXL2's activity as a transcriptional repressor is regulated by phosphorylation. We found that FOXL2 is phosphorylated at a serine residue and, using yeast two-hybrid screening, identified LATS1 as a potential FOXL2-interacting protein. LATS1 is a serine/threonine kinase whose deletion in mice results in an ovarian phenotype similar to POF. Using coimmunoprecipitation and kinase assays, we confirmed that LATS1 binds to FOXL2 and demonstrated that LATS1 phosphorylates FOXL2 at a serine residue. Moreover, we found that FOXL2 and LATS1 are coexpressed in developing mouse gonads and in granulosa cells of small and medium follicles in the mouse ovary. Last, we demonstrated that coexpression with LATS1 enhances FOXL2's activity as a repressor of the StAR promoter, and this results from the kinase activity of LATS1. These results provide novel evidence that FOXL2 is phosphorylated by LATS1 and that this phosphorylation enhances the transcriptional repression of the StAR gene, a marker of granulosa cell differentiation. These data support our hypothesis that phosphorylation of FOXL2 may be a control mechanism regulating the rate of granulosa cell differentiation and hence, follicle maturation, and its dysregulation may contribute to accelerated follicular development and POF in BPES type I. PMID:20407010

  9. ATel draft: Fermi LAT detection of a new Gamma-ray Source PKS 2247-131

    NASA Astrophysics Data System (ADS)

    Buson, S.

    2016-07-01

    The Large Area Telescope (LAT), on board the Fermi Gamma-ray Space Telescope, has observed strong gamma-ray emission from a source positionally consistent with the radio source PKS 2247-131 with coordinates RA=342.4983854 deg, Dec=-12.8546736 deg (J2000; Beasley et al. 2002, ApJS, 141, 13). This source is not in any published LAT catalog and was not detected by AGILE or EGRET.

  10. Reliable Genetic Labeling of Adult-Born Dentate Granule Cells Using Ascl1CreERT2 and GlastCreERT2 Murine Lines

    PubMed Central

    Yang, Sung M.; Alvarez, Diego D.

    2015-01-01

    Newly generated dentate granule cells (GCs) are relevant for input discrimination in the adult hippocampus. Yet, their precise contribution to information processing remains unclear. To address this question, it is essential to develop approaches to precisely label entire cohorts of adult-born GCs. In this work, we used genetically modified mice to allow conditional expression of tdTomato (Tom) in adult-born GCs and characterized their development and functional integration. Ascl1CreERT2;CAGfloxStopTom and GlastCreERT2;CAGfloxStopTom mice resulted in indelible expression of Tom in adult neural stem cells and their lineage upon tamoxifen induction. Whole-cell recordings were performed to measure intrinsic excitability, firing behavior, and afferent excitatory connectivity. Developing GCs were also staged by the expression of early and late neuronal markers. The slow development of adult-born GCs characterized here is consistent with previous reports using retroviral approaches that have revealed that a mature phenotype is typically achieved after 6–8 weeks. Our findings demonstrate that Ascl1CreERT2 and GlastCreERT2 mouse lines enable simple and reliable labeling of adult-born GC lineages within restricted time windows. Therefore, these mice greatly facilitate tagging new neurons and manipulating their activity, required for understanding adult neurogenesis in the context of network remodeling, learning, and behavior. SIGNIFICANCE STATEMENT Our study shows that Ascl1CreERT2 and GlastCreERT2 mice lines can be used to label large cohorts of adult-born dentate granule cells with excellent time resolution. Neurons labeled in this manner display developmental and functional profiles that are in full agreement with previous findings using thymidine analogs and retroviral labeling, thus providing an alternative approach to tackle fundamental questions on circuit remodeling. Because of the massive neuronal targeting and the simplicity of this method, genetic labeling will

  11. MicroRNA-181b promotes ovarian cancer cell growth and invasion by targeting LATS2

    SciTech Connect

    Xia, Ying; Gao, Yan

    2014-05-09

    Highlights: • miR-181b is upregulated in human ovarian cancer tissues. • miR-181b promotes ovarian cancer cell proliferation and invasion. • LATS2 is a direct target of miR-181b. • LATS2 is involved in miR-181b-induced ovarian cancer cell growth and invasion. - Abstract: MicroRNAs (miRNAs) are strongly implicated in tumorigenesis and metastasis. In this study, we showed significant upregulation of miR-181b in ovarian cancer tissues, compared with the normal ovarian counterparts. Forced expression of miR-181b led to remarkably enhanced proliferation and invasion of ovarian cancer cells while its knockdown induced significant suppression of these cellular events. The tumor suppressor gene, LATS2 (large tumor suppressor 2), was further identified as a novel direct target of miR-181b. Specifically, miR-181b bound directly to the 3′-untranslated region (UTR) of LATS2 and suppressed its expression. Restoration of LATS2 expression partially reversed the oncogenic effects of miR-181b. Our results indicate that miR-181b promotes proliferation and invasion by targeting LATS2 in ovarian cancer cells. These findings support the utility of miR-181b as a potential diagnostic and therapeutic target for ovarian cancer.

  12. The Fermi-LAT view of the colliding wind binaries

    NASA Astrophysics Data System (ADS)

    Pshirkov, M. S.

    2016-03-01

    Colliding wind binaries (CWBs) have been considered as a possible high-energy γ-ray sources for some time, however no system other than η Car has been detected. In the Letter, a sample of seven CWBs (WR 11, WR 70, WR 137, WR 140, WR 146, WR 147) which, by means of theoretic modelling, were deemed most promising candidates, was analysed using almost 7 yr of the Fermi-Large Area Telescope (LAT) data. WR 11 (γ2 Vel) was detected at 6.1σ confidence level with a photon flux in 0.1-100 GeV range (1.8 ± 0.6) × 10-9 ph cm-2 s-1 and an energy flux (2.7 ± 0.5) × 10-12 erg cm-2 s-1. At the adopted distance d = 340 pc this corresponds to a luminosity L = (3.7 ± 0.7) × 1031 erg s-1. This luminosity amounts to ˜6 × 10-6 fraction of the total wind kinetic power and ˜1.6 × 10-4 fraction of the power injected into the wind-wind interaction region of this system. Upper limits were set on the high energy flux from the WR 70 and WR 140 systems.

  13. Fermi LAT Observation of Centaurus a Radio Galaxy

    NASA Astrophysics Data System (ADS)

    Sahakyan, N. V.

    2013-01-01

    The results of analysis of approximately 3 year gamma-ray observations (August 2008-July 2011) of the core of radio galaxy Centaurus A with the Fermi Large Area Telescope (Fermi LAT) are presented. Binned likelihood analysis method applying to the data shows that below several GeV the spectrum can be described by a single power-law with photon index Γ = 2.73 ± 0.06. However, at higher energies the new data show significant excess above the extrapolation of the energy spectrum from low energies. The comparison of the corresponding Spectral Energy Distribution (SED) at GeV energies with the SED in the TeV energy band reported by the H.E.S.S. collaboration shows that we deal with two or perhaps even three components of gamma-radiation originating from different regions located within the central 10 kpc of Centaurus A. The analysis of gamma-ray data of Centaurus A lobe accumulated from the beginning of the operation until November 14, 2011 show extension of the HE gamma-ray emission beyond the WMAP radio image in the case of the Northern lobe [9]. The possible origins of gamma-rays from giant radio lobes of Centaurus A are discussed in the context of hadronic and leptonic scenarios.

  14. Fermi-LAT Observation of Supernova Remnant S147

    SciTech Connect

    Katsuta, J.; Uchiyama, Y.; Tanaka, T.; Tajima, H.; Bechtol, K.; Funk, S.; Lande, J.; Ballet, J.; Hanabata, Y.; Lemoine-Goumard, M.; Takahashi, T.; /JAXA, Sagamihara

    2012-08-17

    We present an analysis of gamma-ray data obtained with the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope in the region around 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) x 10{sup -8} photons cm{sup -2} s{sup -1}, corresponding to a luminosity of 1.3 x 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 prominent H{alpha} filaments of 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. Reacceleration of pre-existing CRs and subsequent adiabatic compression in the filaments is sufficient to provide the required energy density of high-energy protons.

  15. Three Millisecond Pulsars in Fermi LAT Unassociated Bright Sources

    NASA Technical Reports Server (NTRS)

    Ransom, S. M.; Ray, P. S.; Camilo, F.; Roberts, M. S. E.; Celik, O.; Wolff, M. T.; Cheung, C. C.; Kerr, M.; Pennucci, T.; DeCesar, M. E.; Cognard, I.; Lyne, A. G.; Stappers, B. W.; Freire, P. C. C.; Grove, J. E.; Abdo, A. A.; Desvignes, G.; Donato, D.; Ferrara, E. C.; Gehrels, N.; Guillemot, L.; Gwon, C.; Johnston, S.; Harding, A. K.; Thompson, D. J.

    2010-01-01

    We searched for radio pulsars in 25 of the non-variable, unassociated sources in the Fermi LAT Bright Source List with the Green Bank Telescope at 820 MHz. We report the discovery of three radio and gamma-ray millisecond pulsar (MSPs) from a high Galactic latitude subset of these sources. All of the pulsars are in binary systems, which would have made them virtually impossible to detect in blind gamma-ray pulsation searches. They seem to be relatively normal, nearby (<= 2 kpc) MSPs. These observations, in combination with the Fermi detection of gamma-rays from other known radio MSPs, imply that most, if not all, radio MSPs are efficient gamma-ray producers. The gamma-ray spectra of the pulsars are power law in nature with exponential cutoffs at a few Ge V, as has been found with most other pulsars. The MSPs have all been detected as X-ray point sources. Their soft X-ray luminosities of approx 10(exp 30) - 10(exp 31) erg/s are typical of the rare radio MSPs seen in X-rays.

  16. Essential amino acid transporter Lat4 (Slc43a2) is required for mouse development

    PubMed Central

    Guetg, Adriano; Mariotta, Luca; Bock, Lukas; Herzog, Brigitte; Fingerhut, Ralph; Camargo, Simone M R; Verrey, François

    2015-01-01

    Amino acid (AA) uniporter Lat4 (Slc43a2) mediates facilitated diffusion of branched-chain AAs, methionine and phenylalanine, although its physiological role and subcellular localization are not known. We report that Slc43a2 knockout mice were born at expected Mendelian frequency but displayed an ∼10% intrauterine growth retardation and low amniotic fluid AAs, suggesting defective transplacental transport. Postnatal growth was strongly reduced, with premature death occurring within 9 days such that further investigations were made within 3 days of birth. Lat4 immunofluorescence showed a strong basolateral signal in the small intestine, kidney proximal tubule and thick ascending limb epithelial cells of wild-type but not Slc43a2 null littermates and no signal in liver and skeletal muscle. Experiments using Xenopus laevis oocytes demonstrated that Lat4 functioned as a symmetrical low affinity uniporter with a K0.5 of ∼5 mm for both in- and efflux. Plasma AA concentration was decreased in Slc43a2 null pups, in particular that of non-essential AAs alanine, serine, histidine and proline. Together with an increased level of plasma long chain acylcarnitines and a strong alteration of liver gene expression, this indicates malnutrition. Attempts to rescue pups by decreasing the litter size or by nutrients injected i.p. did not succeed. Radioactively labelled leucine but not lysine given per os accumulated in the small intestine of Slc43a2null pups, suggesting the defective transcellular transport of Lat4 substrates. In summary, Lat4 is a symmetrical uniporter for neutral essential AAs localizing at the basolateral side of (re)absorbing epithelia and is necessary for early nutrition and development. Key points Lat4 (Slc43a2) transports branched-chain amino acids, phenylalanine and methionine, and is expressed in kidney tubule and small intestine epithelial cells. Using a new knockout model as a negative control, it is shown that Lat4 is expressed at the basolateral

  17. Development of a scintillating fiber tracker for the SSC

    SciTech Connect

    Lewis, R.A.

    1992-10-01

    The Fiber Tracking Group (FTG) of the Solenoidal Detector Collaboration (SDC) is developing a high rate tracking subsystem appropriate for the SDC detector based on scintillating fiber (SciFi) technology. In the past two years a major upgrade in the design was conceived, which reduces the material and cost of the tracker and improves the effectiveness of the tracking system as a trigger element. The results of simulations of the performance of the tracker at Penn State have been very important in keeping the SciFi technology as an attractive option for a tracking system for the SDC collaboration. In the past year an array of scintillating fiber elements has been evaluated in a test beam at Brookhaven. Past experience of Penn State personnel at Brookhaven proved valuable in making the test beam runs a success.

  18. TMT tertiary mirror axis calibration with laser tracker

    NASA Astrophysics Data System (ADS)

    An, Qi-chang; Zhang, Jing-xu; Yang, Fei; Sun, Jing-wei

    2015-03-01

    To calibrate the tracing performance of the thirty meter telescope (TMT) tertiary mirror, for the special requirement of the TMT, the laser tracker is used to verify the motion. Firstly, the deviation is divided into two parts, namely, the repeatable error and the unrepeatable part. Then, based on the laser tracker, the mearturement and evalutation methods of the rigid body motion for the mirror are established, and the Monte Carol method is used to determine the accuracy of the mothod. Lastly, the mothod is applied to the turn table of a classical telescope and the residual error is about 4 arc second. The work of this paper will guide the next desgin and construction work of the thirty meter telescope tertiary mirror.

  19. Commissioning of the ATLAS Semiconductor Tracker with cosmic rays

    NASA Astrophysics Data System (ADS)

    Stanecka, E.; Atlas Sct Collaboration

    2007-10-01

    This paper presents the results of the tests with cosmic rays of the ATLAS Semiconductor Tracker (SCT) as well as operational experience of running the fully integrated silicon detector during the commissioning of the completed SCT. Prior to inserting into ATLAS, the barrel part of the SCT has been integrated with the Transition Radiation Tracker (TRT) barrel and tested with cosmic rays. A sector of 468 SCT modules has been powered and read simultaneously with TRT modules in physics mode. In total 500 thousand events were recorded during cosmic runs and processed with the ATLAS off-line reconstruction software. The SCT performance was measured in terms of the average noise occupancy per channel (4.5×10-5) and the overall efficiency (>99%). The tests with cosmic rays proved full functionality of the complex Detector Control System (DCS) which provides control, monitoring and safety functions for the detector electronics.

  20. The silicon microstrip sensors of the ATLAS semiconductor tracker

    SciTech Connect

    ATLAS SCT Collaboration; Spieler, Helmuth G.

    2007-04-13

    This paper describes the AC-coupled, single-sided, p-in-n silicon microstrip sensors used in the Semiconductor Tracker (SCT) of the ATLAS experiment at the CERN Large Hadron Collider (LHC). The sensor requirements, specifications and designs are discussed, together with the qualification and quality assurance procedures adopted for their production. The measured sensor performance is presented, both initially and after irradiation to the fluence anticipated after 10 years of LHC operation. The sensors are now successfully assembled within the detecting modules of the SCT, and the SCT tracker is completed and integrated within the ATLAS Inner Detector. Hamamatsu Photonics Ltd. supplied 92.2percent of the 15,392 installed sensors, with the remainder supplied by CiS.

  1. VERSATILE TWO-AXIS OPEN-LOOP SOLAR TRACKER CONTROLLER*

    SciTech Connect

    Ward, Christina D; Maxey, L Curt; Evans III, Boyd Mccutchen; Lapsa, Melissa Voss

    2008-01-01

    A versatile single-board controller for two-axis solar tracking applications has been developed and tested on operating solar tracking systems with over two years of field experience. The operating experience gained from the two systems and associated modifications are discussed as representative examples of the practical issues associated with implementing a new two-axis solar tracker design. In this research, open and closed loop control methods were evaluated; however, only the open loop method met the 0.125 tracking accuracy requirement and the requirement to maintain pointing accuracy in hazy and scattered cloudy skies. The open loop algorithm was finally implemented in a microcontroller-based tracking system. Methods of applying this controller hardware to different tracker geometries and hardware are discussed along with the experience gained to date.

  2. Tracker: Image-Processing and Object-Tracking System Developed

    NASA Technical Reports Server (NTRS)

    Klimek, Robert B.; Wright, Theodore W.

    1999-01-01

    Tracker is an object-tracking and image-processing program designed and developed at the NASA Lewis Research Center to help with the analysis of images generated by microgravity combustion and fluid physics experiments. Experiments are often recorded on film or videotape for analysis later. Tracker automates the process of examining each frame of the recorded experiment, performing image-processing operations to bring out the desired detail, and recording the positions of the objects of interest. It can load sequences of images from disk files or acquire images (via a frame grabber) from film transports, videotape, laser disks, or a live camera. Tracker controls the image source to automatically advance to the next frame. It can employ a large array of image-processing operations to enhance the detail of the acquired images and can analyze an arbitrarily large number of objects simultaneously. Several different tracking algorithms are available, including conventional threshold and correlation-based techniques, and more esoteric procedures such as "snake" tracking and automated recognition of character data in the image. The Tracker software was written to be operated by researchers, thus every attempt was made to make the software as user friendly and self-explanatory as possible. Tracker is used by most of the microgravity combustion and fluid physics experiments performed by Lewis, and by visiting researchers. This includes experiments performed on the space shuttles, Mir, sounding rockets, zero-g research airplanes, drop towers, and ground-based laboratories. This software automates the analysis of the flame or liquid s physical parameters such as position, velocity, acceleration, size, shape, intensity characteristics, color, and centroid, as well as a number of other measurements. It can perform these operations on multiple objects simultaneously. Another key feature of Tracker is that it performs optical character recognition (OCR). This feature is useful in

  3. Star spot location estimation using Kalman filter for star tracker.

    PubMed

    Liu, Hai-bo; Yang, Jian-kun; Wang, Jiong-qi; Tan, Ji-chun; Li, Xiu-jian

    2011-04-20

    Star pattern recognition and attitude determination accuracy is highly dependent on star spot location accuracy for the star tracker. A star spot location estimation approach with the Kalman filter for a star tracker has been proposed, which consists of three steps. In the proposed approach, the approximate locations of the star spots in successive frames are predicted first; then the measurement star spot locations are achieved by defining a series of small windows around each predictive star spot location. Finally, the star spot locations are updated by the designed Kalman filter. To confirm the proposed star spot location estimation approach, the simulations based on the orbit data of the CHAMP satellite and the real guide star catalog are performed. The simulation results indicate that the proposed approach can filter out noises from the measurements remarkably if the sampling frequency is sufficient. PMID:21509065

  4. A scintillating fibres tracker detector for archaeological applications

    NASA Astrophysics Data System (ADS)

    Menichelli, M.; Ansoldi, S.; Bari, M.; Basset, M.; Battiston, R.; Blasko, S.; Coren, F.; Fiori, E.; Giannini, G.; Iugovaz, D.; Papi, A.; Reia, S.; Scian, G.

    2007-03-01

    We designed, constructed and operated a cylindrical, scintillating fibres, tracker detector in order to measure the directional flux of cosmic ray muons underground. This instrument named Muon Ground Radiograph (MGR) was developed to study the fluctuation of the density in the soil that causes detection anisotropies in the arrival direction of cosmic ray muons observed in a tracker detector located underground. Density fluctuations may reveal hidden cavities or buried structures and can contribute to archaeological findings. The shape of the detector we used, for this purpose, is cylindrical, 14 cm diameter and 224 cm height, and it can be inserted into a 20 cm diameter hole in the ground at a maximum depth of 30 m. This paper will describe the instrument design and construction and also report some results of two observational campaigns in the town of Aquileia the Claudio and Traiano port.

  5. An isotope identification injection study with GammaTracker

    NASA Astrophysics Data System (ADS)

    Batdorf, Michael T.; Erikson, Luke E.; Seifert, Carolyn E.; Myjak, Mitchell J.; Kirihara, Leslie J.

    2011-10-01

    GammaTracker is a portable handheld radioisotope identifier using position sensitive CdZnTe detectors. High confidence isotope identification is possible on GammaTracker owing to the system's relatively high energy resolution and count rate sensitivity. A study was undertaken to evaluate the isotope identification performance of a prototype unit. Background and source spectra for various nuclides were measured and then randomly sampled to simulate various integration times and source intensities. The resulting spectral data sets were then run through the isotope identification algorithm to determine the probability of detection and the false alarm rate for each nuclide. The process was repeated for various isotope identification input parameters until an optimized set was achieved. This paper presents results from the injection study.

  6. Using Tracker as a pedagogical tool for understanding projectile motion

    NASA Astrophysics Data System (ADS)

    Wee, Loo Kang; Chew, Charles; Hwee Goh, Giam; Tan, Samuel; Lee, Tat Leong

    2012-07-01

    This article reports on the use of Tracker as a pedagogical tool in the effective learning and teaching of projectile motion in physics. When a computer model building learning process is supported and driven by video analysis data, this free Open Source Physics tool can provide opportunities for students to engage in active enquiry-based learning. We discuss the pedagogical use of Tracker to address some common misconceptions concerning projectile motion by allowing students to test their hypothesis by juxtaposing their mental models against the analysis of real-life videos. Initial research findings suggest that allowing learners to relate abstract physics concepts to real life through coupling computer modelling with traditional video analysis could be an innovative and effective way to learn projectile motion.

  7. Sun-Relative Pointing for Dual-Axis Solar Trackers Employing Azimuth and Elevation Rotations

    SciTech Connect

    Riley, Daniel; Hansen, Clifford W.

    2014-12-30

    Dual axis trackers employing azimuth and elevation rotations are common in the field of photovoltaic (PV) energy generation. Accurate sun-tracking algorithms are widely available. However, a steering algorithm has not been available to accurately point the tracker away from the sun such that a vector projection of the sun beam onto the tracker face falls along a desired path relative to the tracker face. We have developed an algorithm which produces the appropriate azimuth and elevation angles for a dual axis tracker when given the sun position, desired angle of incidence, and the desired projection of the sun beam onto the tracker face. Development of this algorithm was inspired by the need to accurately steer a tracker to desired sun-relative positions in order to better characterize the electro-optical properties of PV and CPV modules.

  8. Sun-Relative Pointing for Dual-Axis Solar Trackers Employing Azimuth and Elevation Rotations

    DOE PAGESBeta

    Riley, Daniel; Hansen, Clifford W.

    2014-12-30

    Dual axis trackers employing azimuth and elevation rotations are common in the field of photovoltaic (PV) energy generation. Accurate sun-tracking algorithms are widely available. However, a steering algorithm has not been available to accurately point the tracker away from the sun such that a vector projection of the sun beam onto the tracker face falls along a desired path relative to the tracker face. We have developed an algorithm which produces the appropriate azimuth and elevation angles for a dual axis tracker when given the sun position, desired angle of incidence, and the desired projection of the sun beam ontomore » the tracker face. Development of this algorithm was inspired by the need to accurately steer a tracker to desired sun-relative positions in order to better characterize the electro-optical properties of PV and CPV modules.« less

  9. Clementine Star Tracker Stellar Compass: Final report part 1

    SciTech Connect

    Priest, R.E.; Kordas, J.F.; Lewis, I.T.

    1995-07-01

    The Clementine mission provided the first ever complete, systematic surface mapping of the moon from the ultra-violet to the near-infrared regions. More than 1.7 million images of the moon, earth and space were returned from this mission. Two star stracker stellar compasses (star tracker camera + stellar compass software) were included on the spacecraft, serving a primary function of providing angle updates to the guidance and navigation system. These cameras served a secondary function by providing a wide field of view imaging capability for lunar horizon glow and other dark-side imaging data. This 290 g camera using a 576 x 384 focal plane array and a 17 mm entrance pupil, detected and centroided stars as dim and dimmer than 4.5 m{sub v}, providing rms pointing accuracy of better than 100 {mu}rad pitch and yaw and 450 {mu}rad roll. A description of this light-weight, low power star tracker camera along with a summary of lessons learned is presented. Design goals and preliminary on-orbit performance estimates are addressed in terms of meeting the mission`s primary objective for flight qualifying the sensors for future Department of Defense flights. Documentation generated during the design, analysis, build, test and characterization of the star tracker cameras are presented. Collectively, this documentation represents a small library of information for this camera, and may be used as a framework for producing copy units by commercial enterprises, and therefore satisfies a Department of Defense and Department of Energy goal to transfer technology to industry. However, the considerable knowledge gained from the experience of the individuals involved in the system trades, design, analysis, production, testing and characterization of the star tracker stellar compass is not contained in this documentation.

  10. Resonance interaction in LBNE fine-grained-tracker near detector

    NASA Astrophysics Data System (ADS)

    Duyang, Hongyue; Tian, Xinchun; Mishra, Sanjib R.

    2015-10-01

    This talk is devoted to resonance interaction (RES) in the proposed fine-grained tracker detector (FGT) for LBNE experiment. We use fast MC to study the sensitivity of FGT to RES, and use this measurement as a handle to constrain nuclear effects. Similar analysis is performed on NOMAD data for validation and better understanding. Preliminary RES measurement result using NOMAD data will be reported.

  11. ASTROS - A sub-arcsec CCD star tracker

    NASA Technical Reports Server (NTRS)

    Stanton, R. H.; Alexander, J. W.; Dennison, E. W.; Glavich, T. A.; Salomon, P. M.

    1984-01-01

    The design and application of ASTROS (Advanced Star and Target Reference Optical Sensor) are described, with emphasis on performance test results acquired with a prototype system. The ASTROS tracker provides extremely precise measurements of star image coordinates as inputs to the Image Motion Compensation (IMC) system used to stabilize the science instrument focal planes. Performance levels achieved are dramatic improvements over the levels achieved with image dissector designs with comparable fields of view.

  12. Resonance interaction in LBNE fine-grained-tracker near detector

    SciTech Connect

    Duyang, Hongyue; Tian, Xinchun; Mishra, Sanjib R.

    2015-10-15

    This talk is devoted to resonance interaction (RES) in the proposed fine-grained tracker detector (FGT) for LBNE experiment. We use fast MC to study the sensitivity of FGT to RES, and use this measurement as a handle to constrain nuclear effects. Similar analysis is performed on NOMAD data for validation and better understanding. Preliminary RES measurement result using NOMAD data will be reported.

  13. Star tracker stellar compass for the Clementine mission

    SciTech Connect

    Kordas, J.F.; Lewis, I.T.; Wilson, B.A.

    1995-04-01

    The Clementine mission provided the first ever complete, systematic surface mapping of the moon from the ultra-violet to the near-infrared regions. More than 1.7 million images of the moon, earth and space were returned from this mission. Two star tracker stellar compasses (star tracker camera + stellar compass software) were included on the spacecraft, serving a primary function of providing angle updates to the guidance and navigation system. These cameras served a secondary function by providing a wide field of view imaging capability for lunar horizon glow and other dark-side imaging data. This 290 g camera using a 576 x 384 FPA and a 17 mm entrance pupil, detected and centroided stars as dim and dimmer than 4.5 m{sub v}, providing rms pointing accuracy of better than 100 {micro}rad pitch and yaw and 450 {micro}rad roll. A description of this light-weight, low power star tracker camera along with a summary of lessons learned is presented. Design goals and preliminary on-orbit performance estimates are addressed in terms of meeting the mission`s primary objective for flight qualifying the sensors for future Department of Defense flights.

  14. Characterization of irradiated test structures for the CMS tracker upgrade

    NASA Astrophysics Data System (ADS)

    Lutzer, Bernhard

    2013-12-01

    The CMS collaboration is currently conducting a campaign to identify radiation-hard materials for an upgrade of the CMS tracker. This upgrade is needed to be able to cope with the higher radiation background of the future HL-LHC; additionally the performance of the current tracker will be significantly degraded at the time of the upgrade, requiring a replacement. Several different test structures (TSs) and sensors have been designed for a 6 in. wafer layout. These wafers were produced by an industrial supplier (Hamamatsu Photonics K.K.) and differ by their bulk material (Float Zone, Magnetic Czochralski and CVD-Epi), thickness (from 50 μm to 320 μm) and N-P type doping. These TSs consist of different microelectronic devices including diodes, resistors or MOS structures. They enable the extraction of parameters which are not accessible in a silicon detector and allow the assessment of the quality of the sensors produced on the same wafer. The TSs have been irradiated with protons and neutrons to emulate the radiation damage caused by the particle fluence inside the future CMS tracker after 10 years of operation. This contribution will present measurements of non-irradiated and irradiated test structures at different fluences. The changes of the properties of the microelectronic devices will be discussed as well as the design of the TSs.

  15. A post-processing algorithm for time domain pitch trackers

    NASA Astrophysics Data System (ADS)

    Specker, P.

    1983-01-01

    This paper describes a powerful post-processing algorithm for time-domain pitch trackers. On two successive passes, the post-processing algorithm eliminates errors produced during a first pass by a time-domain pitch tracker. During the second pass, incorrect pitch values are detected as outliers by computing the distribution of values over a sliding 80 msec window. During the third pass (based on artificial intelligence techniques), remaining pitch pulses are used as anchor points to reconstruct the pitch train from the original waveform. The algorithm produced a decrease in the error rate from 21% obtained with the original time domain pitch tracker to 2% for isolated words and sentences produced in an office environment by 3 male and 3 female talkers. In a noisy computer room errors decreased from 52% to 2.9% for the same stimuli produced by 2 male talkers. The algorithm is efficient, accurate, and resistant to noise. The fundamental frequency micro-structure is tracked sufficiently well to be used in extracting phonetic features in a feature-based recognition system.

  16. A kinase shRNA screen links LATS2 and the pRB tumor suppressor

    PubMed Central

    Tschöp, Katrin; Conery, Andrew R.; Litovchick, Larisa; DeCaprio, James A.; Settleman, Jeffrey; Harlow, Ed; Dyson, Nicholas

    2011-01-01

    pRB-mediated inhibition of cell proliferation is a complex process that depends on the action of many proteins. However, little is known about the specific pathways that cooperate with the Retinoblastoma protein (pRB) and the variables that influence pRB's ability to arrest tumor cells. Here we describe two shRNA screens that identify kinases that are important for pRB to suppress cell proliferation and pRB-mediated induction of senescence markers. The results reveal an unexpected effect of LATS2, a component of the Hippo pathway, on pRB-induced phenotypes. Partial knockdown of LATS2 strongly suppresses some pRB-induced senescence markers. Further analysis shows that LATS2 cooperates with pRB to promote the silencing of E2F target genes, and that reduced levels of LATS2 lead to defects in the assembly of DREAM (DP, RB [retinoblastoma], E2F, and MuvB) repressor complexes at E2F-regulated promoters. Kinase assays show that LATS2 can phosphorylate DYRK1A, and that it enhances the ability of DYRK1A to phosphorylate the DREAM subunit LIN52. Intriguingly, the LATS2 locus is physically linked with RB1 on 13q, and this region frequently displays loss of heterozygosity in human cancers. Our results reveal a functional connection between the pRB and Hippo tumor suppressor pathways, and suggest that low levels of LATS2 may undermine the ability of pRB to induce a permanent cell cycle arrest in tumor cells. PMID:21498571

  17. A kinase shRNA screen links LATS2 and the pRB tumor suppressor.

    PubMed

    Tschöp, Katrin; Conery, Andrew R; Litovchick, Larisa; Decaprio, James A; Settleman, Jeffrey; Harlow, Ed; Dyson, Nicholas

    2011-04-15

    pRB-mediated inhibition of cell proliferation is a complex process that depends on the action of many proteins. However, little is known about the specific pathways that cooperate with the Retinoblastoma protein (pRB) and the variables that influence pRB's ability to arrest tumor cells. Here we describe two shRNA screens that identify kinases that are important for pRB to suppress cell proliferation and pRB-mediated induction of senescence markers. The results reveal an unexpected effect of LATS2, a component of the Hippo pathway, on pRB-induced phenotypes. Partial knockdown of LATS2 strongly suppresses some pRB-induced senescence markers. Further analysis shows that LATS2 cooperates with pRB to promote the silencing of E2F target genes, and that reduced levels of LATS2 lead to defects in the assembly of DREAM (DP, RB [retinoblastoma], E2F, and MuvB) repressor complexes at E2F-regulated promoters. Kinase assays show that LATS2 can phosphorylate DYRK1A, and that it enhances the ability of DYRK1A to phosphorylate the DREAM subunit LIN52. Intriguingly, the LATS2 locus is physically linked with RB1 on 13q, and this region frequently displays loss of heterozygosity in human cancers. Our results reveal a functional connection between the pRB and Hippo tumor suppressor pathways, and suggest that low levels of LATS2 may undermine the ability of pRB to induce a permanent cell cycle arrest in tumor cells. PMID:21498571

  18. Cerebral Cortex Hyperthyroidism of Newborn Mct8-Deficient Mice Transiently Suppressed by Lat2 Inactivation

    PubMed Central

    Núñez, Bárbara; Martínez de Mena, Raquel; Obregon, Maria Jesus; Font-Llitjós, Mariona; Nunes, Virginia; Palacín, Manuel; Dumitrescu, Alexandra M.; Morte, Beatriz; Bernal, Juan

    2014-01-01

    Thyroid hormone entry into cells is facilitated by transmembrane transporters. Mutations of the specific thyroid hormone transporter, MCT8 (Monocarboxylate Transporter 8, SLC16A2) cause an X-linked syndrome of profound neurological impairment and altered thyroid function known as the Allan-Herndon-Dudley syndrome. MCT8 deficiency presumably results in failure of thyroid hormone to reach the neural target cells in adequate amounts to sustain normal brain development. However during the perinatal period the absence of Mct8 in mice induces a state of cerebral cortex hyperthyroidism, indicating increased brain access and/or retention of thyroid hormone. The contribution of other transporters to thyroid hormone metabolism and action, especially in the context of MCT8 deficiency is not clear. We have analyzed the role of the heterodimeric aminoacid transporter Lat2 (Slc7a8), in the presence or absence of Mct8, on thyroid hormone concentrations and on expression of thyroid hormone-dependent cerebral cortex genes. To this end we generated Lat2-/-, and Mct8-/yLat2-/- mice, to compare with wild type and Mct8-/y mice during postnatal development. As described previously the single Mct8 KO neonates had a transient increase of 3,5,3′-triiodothyronine concentration and expression of thyroid hormone target genes in the cerebral cortex. Strikingly the absence of Lat2 in the double Mct8Lat2 KO prevented the effect of Mct8 inactivation in newborns. The Lat2 effect was not observed from postnatal day 5 onwards. On postnatal day 21 the Mct8 KO displayed the typical pattern of thyroid hormone concentrations in plasma, decreased cortex 3,5,3′-triiodothyronine concentration and Hr expression, and concomitant Lat2 inactivation produced little to no modifications. As Lat2 is expressed in neurons and in the choroid plexus, the results support a role for Lat2 in the supply of thyroid hormone to the cerebral cortex during early postnatal development. PMID:24819605

  19. Two years of variable gamma-ray sky explored by Fermi LAT Flare Advocates

    NASA Astrophysics Data System (ADS)

    Ciprini, Stefano; Gasparrini, Dario; Fermi LAT Collaboration

    The Flare Advocate/Gamma-ray Sky Watcher (FA-GSW) activity is part of the Fermi LAT Science Operations aiming to supply a prompt outlook service to the quick-look Automatic Science Processing (ASP) products, and in general to the LAT sky, day by day. The FA-GSW points out potentially interesting seeds for LAT science and the different LAT science groups, while communicating basic and relevant news to the external astrophysical community, in order to increase the rate of multi-frequency observations and follow-ups that could maximize science return. During the first two years of the Fermi mission, FA-GSWs discovered, for example, many gamma-ray flares and longer-term brightening from variable blazars, unidentified transients near the Galactic plane, confirmed the quiet sun gamma-ray emission, compiled many Astronomical Telegrams, pointed out possible new gamma-ray sources, and provided starting seeds for more than a dozen LAT papers on single sources and follow-up multifrequency campaigns. Some highlights of these two year of crucial service-activity are summarized in this poster.

  20. NuLat: A Novel Design for a Reactor Anti-Neutrino Detector

    NASA Astrophysics Data System (ADS)

    Rountree, S. Derek; NuLat Collaboration

    2015-04-01

    NuLat is a proposed very-short baseline (3-10m) reactor electron antineutrino (anti-νe) experiment that will probe the current best fit for light sterile neutrino mixing, the 5 MeV excess seen in current short baseline reactor experiments, and serve as a portable surface detector for cooperative (~ 30m baseline) surface monitoring of reactors. The NuLat detector will use an optically segmented 3D Raghavan optical lattice (ROL) detector that channels light via total internal reflection from a scintillation event down the 3 primary axes to the detector faces. The high degree of segmentation allows for each voxel's energy to be determined independently of other voxels, thus providing high temporal and spatial resolution and energy reconstruction independent of position. NuLat detects anti-νe via inverse beta decay (IBD), which produces a positron and a neutron. Most of the time, the positron deposits its kinetic energy into a single voxel allowing superior derivation of the incident anti-νe's energy. The final state neutron is captured via (n, α) on 6 Li or 10 B after a characteristic delay time giving a coincidence tag. This talk will discuss the physics reach of NuLat using a solid loaded scintillator, and the timeline of the NuLat reactor anti-νe program. This research has been funded in part by the National Science Foundation on Award Numbers 1001394 and 1001078.

  1. Constraints on the pMSSM from LAT Observations of Dwarf Spheroidal Galaxies

    SciTech Connect

    Cotta, R.C.; Drlica-Wagner, A.; Murgia, S.; Bloom, E.D.; Hewett, J.L.; Rizzo, T.G.; /SLAC

    2012-03-15

    We examine the ability for the Large Area Telescope (LAT) to constrain Minimal Supersymmetric Standard Model (MSSM) dark matter through a combined analysis of Milky Way dwarf spheroidal galaxies. We examine the Lightest Supersymmetric Particles (LSPs) for a set of {approx}71k experimentally valid supersymmetric models derived from the phenomenological-MSSM (pMSSM). We find that none of these models can be excluded at 95% confidence by the current analysis; nevertheless, many lie within the predicted reach of future LAT analyses. With two years of data, we find that the LAT is currently most sensitive to light LSPs (mLSP < 50 GeV) annihilating into {tau}-pairs and heavier LSPs annihilating into b{bar b}. Additionally, we find that future LAT analyses will be able to probe some LSPs that form a sub-dominant component of dark matter. We directly compare the LAT results to direct detection experiments and show the complementarity of these search methods.

  2. PARD3 induces TAZ activation and cell growth by promoting LATS1 and PP1 interaction

    PubMed Central

    Lv, Xian-Bo; Liu, Chen-Ying; Wang, Zhen; Sun, Yi-Ping; Xiong, Yue; Lei, Qun-Ying; Guan, Kun-Liang

    2015-01-01

    The Hippo pathway plays a major role in organ size control, and its dysregulation contributes to tumorigenesis. The major downstream effectors of the Hippo pathway are the YAP/TAZ transcription co-activators, which are phosphorylated and inhibited by the Hippo pathway kinase LATS1/2. Here, we report a novel mechanism of TAZ regulation by the tight junction protein PARD3. PARD3 promotes the interaction between PP1A and LATS1 to induce LATS1 dephosphorylation and inactivation, therefore leading to dephosphorylation and activation of TAZ. The cytoplasmic, but not the tight junction complex associated, PARD3 is responsible for TAZ regulation. Our study indicates a potential molecular basis for cell growth-promoting function of PARD3 by modulating the Hippo pathway signaling in response to cell contact and cell polarity signals. PMID:26116754

  3. The X-Ray Counterpart to LAT PSR J2021+4026 and Its Interesting Spectrum

    NASA Technical Reports Server (NTRS)

    Weisskopf, Martin C.; Becker, W.; Carraminana, A.; De Luca, A.; Dormandy, M.; Harding, A.; Kanbach, G.; O'Dell, S. L.; Parkinson, P. Saz; Ray, P.; Razzano, M.; Romani, R.; Tennant, A. F.; Swarz, D. A.; Thompson, D.; Ziegler, M.

    2011-01-01

    We report on the likely identification of the X-ray counterpart to LAT PSR J2021+4026, using the Chandra X-Ray Observatory ACIS-S3 and timing analysis of Large Area telescope (LAT) data from the Fermi satellite. The X-ray source that lies closest (10 arcsec) to the position determined from the Fermi-LAT timing solution has no cataloged infrared-to-visible counterpart and we have set an upper limit to its optical I and R band emission. The source exhibits a X-ray spectrum which is different when compared to Geminga and CTA 1, and this may have implications for the evolutionary track of radio-quiet gamma-ray pulsars.

  4. Inverse sparse tracker with a locally weighted distance metric.

    PubMed

    Wang, Dong; Lu, Huchuan; Xiao, Ziyang; Yang, Ming-Hsuan

    2015-09-01

    Sparse representation has been recently extensively studied for visual tracking and generally facilitates more accurate tracking results than classic methods. In this paper, we propose a sparsity-based tracking algorithm that is featured with two components: 1) an inverse sparse representation formulation and 2) a locally weighted distance metric. In the inverse sparse representation formulation, the target template is reconstructed with particles, which enables the tracker to compute the weights of all particles by solving only one l1 optimization problem and thereby provides a quite efficient model. This is in direct contrast to most previous sparse trackers that entail solving one optimization problem for each particle. However, we notice that this formulation with normal Euclidean distance metric is sensitive to partial noise like occlusion and illumination changes. To this end, we design a locally weighted distance metric to replace the Euclidean one. Similar ideas of using local features appear in other works, but only being supported by popular assumptions like local models could handle partial noise better than holistic models, without any solid theoretical analysis. In this paper, we attempt to explicitly explain it from a mathematical view. On that basis, we further propose a method to assign local weights by exploiting the temporal and spatial continuity. In the proposed method, appearance changes caused by partial occlusion and shape deformation are carefully considered, thereby facilitating accurate similarity measurement and model update. The experimental validation is conducted from two aspects: 1) self validation on key components and 2) comparison with other state-of-the-art algorithms. Results over 15 challenging sequences show that the proposed tracking algorithm performs favorably against the existing sparsity-based trackers and the other state-of-the-art methods. PMID:25935033

  5. Monitoring with Trackers Based on Semi-Quantitative Models

    NASA Technical Reports Server (NTRS)

    Kuipers, Benjamin

    1997-01-01

    In three years of NASA-sponsored research preceding this project, we successfully developed a technology for: (1) building qualitative and semi-quantitative models from libraries of model-fragments, (2) simulating these models to predict future behaviors with the guarantee that all possible behaviors are covered, (3) assimilating observations into behaviors, shrinking uncertainty so that incorrect models are eventually refuted and correct models make stronger predictions for the future. In our object-oriented framework, a tracker is an object which embodies the hypothesis that the available observation stream is consistent with a particular behavior of a particular model. The tracker maintains its own status (consistent, superceded, or refuted), and answers questions about its explanation for past observations and its predictions for the future. In the MIMIC approach to monitoring of continuous systems, a number of trackers are active in parallel, representing alternate hypotheses about the behavior of a system. This approach is motivated by the need to avoid 'system accidents' [Perrow, 1985] due to operator fixation on a single hypothesis, as for example at Three Mile Island. As we began to address these issues, we focused on three major research directions that we planned to pursue over a three-year project: (1) tractable qualitative simulation, (2) semiquantitative inference, and (3) tracking set management. Unfortunately, funding limitations made it impossible to continue past year one. Nonetheless, we made major progress in the first two of these areas. Progress in the third area as slower because the graduate student working on that aspect of the project decided to leave school and take a job in industry. I enclosed a set of abstract of selected papers on the work describe below. Several papers that draw on the research supported during this period appeared in print after the grant period ended.

  6. 50 CFR Table 2c to Part 660... - Sablefish North of 36° N. lat. Allocations, 2014 and Beyond

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Sablefish North of 36° N. lat. Allocations, 2014 and Beyond 2c Table 2c to Part 660, Subpart C Wildlife and Fisheries FISHERY CONSERVATION... of 36° N. lat. Allocations, 2014 and Beyond ER03JA13.062...

  7. 50 CFR Table 2c to Part 660... - Sablefish North of 36°N. lat. Allocations, 2012, and beyond

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Sablefish North of 36°N. lat. Allocations, 2012, and beyond 2c Table 2c to Part 660, Subpart C Wildlife and Fisheries FISHERY CONSERVATION... of 36°N. lat. Allocations, 2012, and beyond er11my11.005...

  8. 50 CFR Table 2c to Part 660... - Sablefish North of 36°N. lat. Allocations, 2012, and beyond

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Sablefish North of 36°N. lat. Allocations, 2012, and beyond 2c Table 2c to Part 660, Subpart C Wildlife and Fisheries FISHERY CONSERVATION... of 36°N. lat. Allocations, 2012, and beyond er11my11.005...

  9. The STAR Heavy Flavor Tracker PXL detector readout electronics

    NASA Astrophysics Data System (ADS)

    Schambach, J.; Contin, G.; Greiner, L.; Stezelberger, T.; Sun, X.; Szelezniak, M.; Vu, C.

    2016-01-01

    The Heavy Flavor Tracker (HFT) is a recently installed micro-vertex detector upgrade to the STAR experiment at RHIC, consisting of three subsystems with various technologies of silicon sensors arranged in 4 concentric cylinders. The two innermost layers of the HFT close to the beam pipe, the Pixel ("PXL") subsystem, employ CMOS Monolithic Active Pixel Sensor (MAPS) technology that integrate the sensor, front-end electronics, and zero-suppression circuitry in one silicon die. This paper presents selected characteristics of the PXL detector part of the HFT and the hardware, firmware and software associated with the readout system for this detector.

  10. Physics sensitivity studies of Fine-Grained Tracker

    SciTech Connect

    Tian, Xinchun; Mishra, Sanjib R.; Petti, Roberto; Hongyue, Duyang

    2015-10-15

    The reference design of the near detector for the LBNE experiment is a high-resolution Fine-Grained Tracker (FGT). We performed sensitivity studies – critical to constraining the systematics in oscillation searches – of measurements of (1) the absolute neutrino flux, (2) neutrino-nucleon quasi-elastic (QE) and (3) resonance (Res) interactions. In QE and Res emphasis is laid in identifying in situ measurables that help constrain nuclear effects such as initial state pair wise correlations and final state interactions.

  11. Acquisition and track algorithms for the Astros star tracker

    NASA Technical Reports Server (NTRS)

    Shalom, E.; Alexander, J. W.; Stanton, R. H.

    1985-01-01

    The Astros star tracker has been designed for an employment with the Space Shuttle. An achievement of the performance levels needed has required critical trade-offs between the hardware design and the control algorithms. This paper provides a description of the development of the acquisition and track algorithms. Attention is given to an Astros system overview, a system firmware description, cluster evaluation, guide star selection, exposure time determination, video data input, update interval timing, exposure time sequencing full frame video A/D conversion, analog threshold for acquisition, minimum threshold determination, and the theoretical basis for the track algorithm.

  12. Evaluating a robust contour tracker on echocardiographic sequences.

    PubMed

    Jacob, G; Noble, J A; Mulet-Parada, M; Blake, A

    1999-03-01

    In this paper we present an evaluation of a robust visual image tracker on echocardiographic image sequences. We show how the tracking framework can be customized to define an appropriate shape space that describes heart shape deformations that can be learnt from a training data set. We also investigate energy-based temporal boundary enhancement methods to improve image feature measurement. Results are presented demonstrating real-time tracking on real normal heart motion data sequences and abnormal synthesized and real heart motion data sequences. We conclude by discussing some of our current research efforts. PMID:10709697

  13. A Case of Leser-Trélat Syndrome Associated with a Renal Cell Carcinoma

    PubMed Central

    Barth, Dietrich; Puhlmann, Silvio; Barth, Joachim

    2015-01-01

    Seborrheic keratoses can often be found in elderly people. In general, they appear gradually. In cases of a sudden eruption with itching it might be paraneoplastic. Although some authors doubt the existence of the paraneoplastic Leser-Trélat syndrome, we present a case of sudden eruption of seborrheic keratoses connected with a newly diagnosed renal cell carcinoma. As far as we know, this is the first case report of a Leser-Trélat syndrome with a malignancy of the kidney. PMID:26500537

  14. A Case of Leser-Trélat Syndrome Associated with a Renal Cell Carcinoma.

    PubMed

    Barth, Dietrich; Puhlmann, Silvio; Barth, Joachim

    2015-01-01

    Seborrheic keratoses can often be found in elderly people. In general, they appear gradually. In cases of a sudden eruption with itching it might be paraneoplastic. Although some authors doubt the existence of the paraneoplastic Leser-Trélat syndrome, we present a case of sudden eruption of seborrheic keratoses connected with a newly diagnosed renal cell carcinoma. As far as we know, this is the first case report of a Leser-Trélat syndrome with a malignancy of the kidney. PMID:26500537

  15. Post flight analysis of NASA standard star trackers recovered from the solar maximum mission

    NASA Technical Reports Server (NTRS)

    Newman, P.

    1985-01-01

    The flight hardware returned after the Solar Maximum Mission Repair Mission was analyzed to determine the effects of 4 years in space. The NASA Standard Star Tracker would be a good candidate for such analysis because it is moderately complex and had a very elaborate calibration during the acceptance procedure. However, the recovery process extensively damaged the cathode of the image dissector detector making proper operation of the tracker and a comparison with preflight characteristics impossible. Otherwise, the tracker functioned nominally during testing.

  16. Human L-type amino acid transporter 1 (LAT1): characterization of function and expression in tumor cell lines.

    PubMed

    Yanagida, O; Kanai, Y; Chairoungdua, A; Kim, D K; Segawa, H; Nii, T; Cha, S H; Matsuo, H; Fukushima, J; Fukasawa, Y; Tani, Y; Taketani, Y; Uchino, H; Kim, J Y; Inatomi, J; Okayasu, I; Miyamoto, K; Takeda, E; Goya, T; Endou, H

    2001-10-01

    System L is a major nutrient transport system responsible for the transport of large neutral amino acids including several essential amino acids. We previously identified a transporter (L-type amino acid transporter 1: LAT1) subserving system L in C6 rat glioma cells and demonstrated that LAT1 requires 4F2 heavy chain (4F2hc) for its functional expression. Since its oncofetal expression was suggested in the rat liver, it has been proposed that LAT1 plays a critical role in cell growth and proliferation. In the present study, we have examined the function of human LAT1 (hLAT1) and its expression in human tissues and tumor cell lines. When expressed in Xenopus oocytes with human 4F2hc (h4F2hc), hLAT1 transports large neutral amino acids with high affinity (K(m)= approximately 15- approximately 50 microM) and L-glutamine and L-asparagine with low affinity (K(m)= approximately 1.5- approximately 2 mM). hLAT1 also transports D-amino acids such as D-leucine and D-phenylalanine. In addition, we show that hLAT1 accepts an amino acid-related anti-cancer agent melphalan. When loaded intracellularly, L-leucine and L-glutamine but not L-alanine are effluxed by extracellular substrates, confirming that hLAT1 mediates an amino acid exchange. hLAT1 mRNA is highly expressed in the human fetal liver, bone marrow, placenta, testis and brain. We have found that, while all the tumor cell lines examined express hLAT1 messages, the expression of h4F2hc is varied particularly in leukemia cell lines. In Western blot analysis, hLAT1 and h4F2hc have been confirmed to be linked to each other via a disulfide bond in T24 human bladder carcinoma cells. Finally, in in vitro translation, we show that hLAT1 is not a glycosylated protein even though an N-glycosylation site has been predicted in its extracellular loop, consistent with the property of the classical 4F2 light chain. The properties of the hLAT1/h4F2hc complex would support the roles of this transporter in providing cells with essential

  17. Precision Attitude Determination System (PADS) system design and analysis: Single-axis gimbal star tracker

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The feasibility is evaluated of an evolutionary development for use of a single-axis gimbal star tracker from prior two-axis gimbal star tracker based system applications. Detailed evaluation of the star tracker gimbal encoder is considered. A brief system description is given including the aspects of tracker evolution and encoder evaluation. System analysis includes evaluation of star availability and mounting constraints for the geosynchronous orbit application, and a covariance simulation analysis to evaluate performance potential. Star availability and covariance analysis digital computer programs are included.

  18. Fourth Workshop on Science with the New Generation of High Energy Gamma-ray Experiments

    NASA Astrophysics Data System (ADS)

    Massai, Marco Maria; Omodei, Nicola; Spandre, Gloria

    I. Space-based telescope. Integral-4 years in orbit / P. Umbertini, P. Caraveo. The Suzaku mission / K. Yamaoka. The Swift mission: two years of operation / A. Moretti. Gamma-ray astrophysics with AGILE / F.Longo et al., The AGILE collaboration. The GLAST mission / J.E. McEnery -- II. Ground-based telescope. Recent results from CANGAROO / M. Mori for the CANGAROO team. The H.E.S.S. project / C. Masterson for the H.E.S.S. collaboration. The MAGIC experiment / N. Turini for the MAGIC collaboration. VERITAS: status and performance / J. Holder for the VERITAS collaboration -- III. Galactic variable sources. Galactic variable sky with EGRET and GLAST / S. Digel. Galactic variable sources observed with H.E.S.S. / N. Komin for the H.E.S.S collaboration. Gamma ray pulsars in the GLAST era / M. Razzano. Solving the riddle of unidentified high-energy gamma-ray sources / P. Caraveo. Supernovae and gamma-ray burst / M. Della Valle. First cycle of MAGIC galactic observations / J. Cortina for the MAGIC collaboration. Gamma-rays and neutrinos from a SNR in the galactic center / V. Cavasinni, D. Grasso, L. Maccione. Solving GRBs and SGRs puzzles by precessing jets / D. Fargion, O. Lanciano, P. Oliva -- IV. Extragalactic sources. Multiwavelength observations and theories of blazers / G. Tosti. AGN observations with the MAGIC telescope / C. Bigongiari for the MAGIC collaboration. Gamma ray bursts/ L. Amati. X-rays and GeV flares in GRB light curves / A. Galli ... [et al.]. The highest energy emission from gamma ray bursts: MILAGRO's constraints and HAWC's potential / B. Dingus for the MILAGRO and HAWC collaborations. Observation of GRB with the MAGIC telescope / N. Galante, P. Piccioli for the MAGIC collaboration. GRB 060218 and the outliers with respect to the E-E correlation / G. Ghirlanda, G. Ghibellini -- V. Poster session. Study of the performance and calibration of the GLAST-LAT silicon tracker / M. Brigida, N. Giglietto, P. Spinelli. The online monitor for the GLAST

  19. A study of L-leucine, L-phenylalanine and L-alanine transport in the perfused rat mammary gland: possible involvement of LAT1 and LAT2.

    PubMed

    Shennan, D B; Calvert, D T; Travers, M T; Kudo, Y; Boyd, C A R

    2002-08-19

    The transport of L-leucine, L-phenylalanine and L-alanine by the perfused lactating rat mammary gland has been examined using a rapid, paired-tracer dilution technique. The clearances of all three amino acids by the mammary gland consisted of a rising phase followed by a rapid fall-off, respectively, reflecting influx and efflux of the radiotracers. The peak clearance of L-leucine was inhibited by BCH (65%) and D-leucine (58%) but not by L-proline. The inhibition of L-leucine clearance by BCH and D-leucine was not additive. L-leucine inhibited the peak clearance of radiolabelled L-leucine by 78%. BCH also inhibited the peak clearance of L-phenylalanine (66%) and L-alanine (33%) by the perfused mammary gland. Lactating rat mammary tissue was found to express both LAT1 and LAT2 mRNA. The results suggest that system L is situated in the basolateral aspect of the lactating rat mammary epithelium and thus probably plays a central role in neutral amino acid uptake from blood. The finding that L-alanine uptake by the gland was inhibited by BCH suggests that LAT2 may make a significant contribution to neutral amino acid uptake by the mammary epithelium. PMID:12101005

  20. Low-background tracker development for SuperNEMO

    SciTech Connect

    Mott, James; Collaboration: SuperNEMO Collaboration; and others

    2013-08-08

    The SuperNEMO experiment will search for neutrinoless double beta decay (0νββ) with a target sensitivity of T{sub 1/2}(0ν) > 10{sup 26} years, corresponding to an effective neutrino mass of 50-100 meV. At its heart there is a low-background gaseous tracking detector which allows for extremely efficient background rejection and, if 0νββ is observed, may provide important insights into the mechanism via which it may be mediated. Radon inside the tracker, which can mimic rare ββ events, is one of the most dangerous backgrounds for SuperNEMO. To reach the target sensitivity the radon concentration inside the tracking volume must be < 0.15 mBq/m{sup 3}. To reach this challengingly-low level of radon, a considerable program of R and D has been undertaken. This includes automation of the tracker-wiring process, development of a dedicated setup to measure radon diffusion and a 'radon concentration line' which will be able to measure levels of radon in the μBq/m{sup 3} range.

  1. Embedded pitch adapters for the ATLAS Tracker Upgrade

    NASA Astrophysics Data System (ADS)

    Ullan, Miguel; Benitez, Victor; Pellegrini, Giulio; Fleta, Celeste; Lozano, Manuel; Lacasta, Carlos; Soldevila, Urmila; Garcia, Carmen

    2013-12-01

    In the current ATLAS tracker modules, sensor bonding pads are placed on their corresponding strips and oriented along the strips. This creates a difference in pitch and orientation between sensor bond pads and readout electronics bond pads. Therefore, a pitch adapter (PA), or “fan-in”, is needed. The purpose of these PA is the electrical interconnection of every channel from the detector bonding pads to the read-out chips, adapting the different pad pitch. Our new approach is to build those PAs inside the sensor; this is what we call Embedded Pitch Adapters. The idea is to use an additional metal layer in order to define a new group of pads, connected to the strips via tracks with the second metal. The embedded PAs have been fabricated on 4-in. prototype sensors for the ATLAS-Upgrade Endcap Tracker to test their performance and suitability. The tests confirm proper fabrication of the second metal tracks, and no effects on detector performance. No indication of cross-talk between first and second metal channels has been observed. A small indication of possible signal pick-up from the bulk has been observed in a few channels, which needs to be further investigated.

  2. Solar kinetics` photovoltaic concentrator module and tracker development

    SciTech Connect

    White, D.L.; Howell, B.

    1995-11-01

    Solar Kinetics, Inc., has been developing a point-focus concentrating photovoltaic module and tracker system under contract to Sandia National Laboratories. The primary focus of the contract was to achieve a module design that was manufacturable and passed Sandia`s environmental testing. Nine modules of two variations were assembled, tested, and characterized in Phase 1, and results of these tests were promising, with module efficiency approaching the theoretical limit achievable with the components used. The module efficiency was 11.9% at a solar irradiance of 850 W/sq m and an extrapolated cell temperature of 25 C. Improvements in module performance are anticipated as cell efficiencies meet their expectations. A 2-kW tracker and controller accommodating 20 modules was designed, built, installed, and operated at Solar Kinetics` test site. The drive used many commercially available components in an innovative arrangement to reduce cost and increase reliability. Backlash and bearing play were controlled by use of preloaded, low slip-stick, synthetic slide bearings. The controller design used a standard industrial programmable logic controller to perform ephemeris calculations, operate the actuators, and monitor encoders.

  3. An adaptive tracker for ShipIR/NTCS

    NASA Astrophysics Data System (ADS)

    Ramaswamy, Srinivasan; Vaitekunas, David A.

    2015-05-01

    A key component in any image-based tracking system is the adaptive tracking algorithm used to segment the image into potential targets, rank-and-select the best candidate target, and the gating of the selected target to further improve tracker performance. This paper will describe a new adaptive tracker algorithm added to the naval threat countermeasure simulator (NTCS) of the NATO-standard ship signature model (ShipIR). The new adaptive tracking algorithm is an optional feature used with any of the existing internal NTCS or user-defined seeker algorithms (e.g., binary centroid, intensity centroid, and threshold intensity centroid). The algorithm segments the detected pixels into clusters, and the smallest set of clusters that meet the detection criterion is obtained by using a knapsack algorithm to identify the set of clusters that should not be used. The rectangular area containing the chosen clusters defines an inner boundary, from which a weighted centroid is calculated as the aim-point. A track-gate is then positioned around the clusters, taking into account the rate of change of the bounding area and compensating for any gimbal displacement. A sequence of scenarios is used to test the new tracking algorithm on a generic unclassified DDG ShipIR model, with and without flares, and demonstrate how some of the key seeker signals are impacted by both the ship and flare intrinsic signatures.

  4. Tracker Performance Improvement Using Multiple-Sensor Data

    NASA Astrophysics Data System (ADS)

    Dayton, David C.; Asher, Kelly; Schneeberger, Timothy J.

    1989-09-01

    The increase in target signature information inherent in multi-spectral techniques can be used to increase tracker knowledge of current and predicted target states. In addition to the target location, the velocity, acceleration states, and target aspect angle, for example, can be measured. Aspect angle can be used to limit the possible future states of the target (aircraft, for example, have maximum maneuverability along an axis perpendicular to the wing plane.) Aspect angle, coupled with information concerning maximum target acceleration capabilities, can be used to provide an 'envelope' of possible future target locations. This envelope and position prediction are updated with each observation of the target status. A target pattern recognition algorithm has been used to classify target images, estimating both object identification and aspect angle. A modified form of the moments invariant technique, combined with a maximum likelihood classifier, has been developed and tested against imagery acquired with a laboratory image acquisition and analysis system. Simulations of combined motion and aspect angle sensing trackers indicated enhanced performance over systems with kinematic information only. A database of target imagery has been created, and algorithm accuracy as a function of signal-to-noise ratio has been determined. The effects of several pre-processing steps on the electro-optical sensor aspect angle measurement have also been studied. Critical invariance properties have been examined in a limited number of tests.

  5. Development of femtosecond optical frequency comb laser tracker

    NASA Astrophysics Data System (ADS)

    Yang, Ju-qing; Zhou, Wei-hu; Dong, Deng-feng; Zhang, Zi-li; Lao, Da-bao; Ji, Rong-yi; Wang, Da-yong

    2016-01-01

    A new type femtosecond laser tracker is one high precision measurement instrument with urgent need in science research region and industrial manufacture field. This paper focuses on the operational principle and the structure development of the femtosecond laser tracer, and the method of error compensation as well. The system modules were studied and constructed. The femtosecond frequency comb module was firstly analyzed and developed. The femtosecond laser frequency comb performed perfectly high precise distance measurement for laser tracker. The experimental result showed that the stability of repetition rate reached 3.0×10-12@1s and the stability of carrier envelop offset reached 1.0×10-10@1s. The initial experiment showed that measurement error was less than 1ppm. Later the error compensation module was introduced, and the optoelectronic aiming and tracking control module was built. The actual test result showed that the stability of miss distance was better than 2.0 μm, the tracking speed could reach 2m/s.

  6. Thermal performance of microinverters on dual-axis trackers

    NASA Astrophysics Data System (ADS)

    Hossain, Mohammad A.; Peshek, Timothy J.; Xu, Yifan; Ji, Liang; Sun, Jiayang; Abramson, Alexis; French, Roger H.

    2014-10-01

    Time-series insolation, environmental, thermal and power data were analyzed in a statistical analytical approach to identify the thermal performance of microinverters on dual-axis trackers under real-world operating conditions. This study analyzed 24 microinverters connected to 8 different brands of photovoltaic (PV) modules from July through October 2013 at the Solar Durability and Lifetime Extension (SDLE) SunFarm at Case Western Reserve University. Exploratory data analysis shows that the microinverter's temperature is strongly correlated with ambient temperature and PV module temperature, and moderately correlated with irradiance and AC power. Noontime data analysis reveals the variations of thermal behavior across different brands of PV module. Hierarchical clustering using the Euclidean distance measure principle was applied to noontime microinverter temperature data to group the similarly behaved microinverters. A multiple regression predictive model has been developed based on ambient temperature, PV module temperature, irradiance and AC power data to predict the microinverters temperature connected with different brands PV modules on dual-axis trackers.

  7. Electromagnetic tracker accuracy in the CyberKnife suite

    NASA Astrophysics Data System (ADS)

    Wilson, Emmanuel; Slack, Rebecca; Banovac, Filip; Dieterich, Sonja; Zhang, Hui; Cleary, Kevin

    2006-03-01

    Electromagnetic trackers have found inroads into medical applications as a tool for navigation in recent years. Their susceptibility to interference from both electromagnetic and ferromagnetic sources have prompted several accuracy assessment studies in past years. To the best of our knowledge, this is the first accuracy study conducted to characterize measurement accuracy of an NDI AURORA electromagnetic tracker within a CyberKnife radiosurgery suite. CyberKnife is a frameless, stereotactic radiosurgery device used to ablate tumors within the brain, spine and in recent years, the chest and abdomen. This paper uses a data collection protocol to collect uniformly distributed data points within a subset of the AURORA measurement volume in a CyberKnife suite. The key aim of the study is to determine the extent to which large metal components of the CyberKnife stereotactic radiosurgery device and robot mount contribute to overall system performance for the AURORA electromagnetic device. A secondary goal of the work is to determine the variation in accuracy and device behavior with the presence of ionizing radiation when the LINAC is turned on.

  8. Compact near-to-eye display with integrated gaze tracker

    NASA Astrophysics Data System (ADS)

    Järvenpää, Toni; Aaltonen, Viljakaisa

    2008-04-01

    Near-to-Eye Display (NED) offers a big screen experience to the user anywhere, anytime. It provides a way to perceive a larger image than the physical device itself is. Commercially available NEDs tend to be quite bulky and uncomfortable to wear. However, by using very thin plastic light guides with diffractive structures on the surfaces, many of the known deficiencies can be notably reduced. These Exit Pupil Expander (EPE) light guides enable a thin, light, user friendly and high performing see-through NED, which we have demonstrated. To be able to interact with the displayed UI efficiently, we have also integrated a video-based gaze tracker into the NED. The narrow light beam of an infrared light source is divided and expanded inside the same EPEs to produce wide collimated beams out from the EPE towards the eyes. Miniature video camera images the cornea and eye gaze direction is accurately calculated by locating the pupil and the glints of the infrared beams. After a simple and robust per-user calibration, the data from the highly integrated gaze tracker reflects the user focus point in the displayed image which can be used as an input device for the NED system. Realizable applications go from eye typing to playing games, and far beyond.

  9. Dynamic imaging model and parameter optimization for a star tracker.

    PubMed

    Yan, Jinyun; Jiang, Jie; Zhang, Guangjun

    2016-03-21

    Under dynamic conditions, star spots move across the image plane of a star tracker and form a smeared star image. This smearing effect increases errors in star position estimation and degrades attitude accuracy. First, an analytical energy distribution model of a smeared star spot is established based on a line segment spread function because the dynamic imaging process of a star tracker is equivalent to the static imaging process of linear light sources. The proposed model, which has a clear physical meaning, explicitly reflects the key parameters of the imaging process, including incident flux, exposure time, velocity of a star spot in an image plane, and Gaussian radius. Furthermore, an analytical expression of the centroiding error of the smeared star spot is derived using the proposed model. An accurate and comprehensive evaluation of centroiding accuracy is obtained based on the expression. Moreover, analytical solutions of the optimal parameters are derived to achieve the best performance in centroid estimation. Finally, we perform numerical simulations and a night sky experiment to validate the correctness of the dynamic imaging model, the centroiding error expression, and the optimal parameters. PMID:27136791

  10. Planar silicon sensors for the CMS tracker upgrade

    NASA Astrophysics Data System (ADS)

    Junkes, Alexandra

    2013-12-01

    The CMS tracker collaboration has initiated a large material investigation and irradiation campaign to identify the silicon material and design that fulfills all requirements for silicon tracking detectors for the high-luminosity phase of the Large Hadron Collider (HL-LHC). A variety of silicon p-in-n and n-in-p test-sensors made from Float Zone, Deep-Diffused FZ and Magnetic Czochralski materials were manufactured by one single industrial producer, thus guaranteeing similar conditions for the production and design of the test-structures. Properties of different silicon materials and design choices have been systematically studied and compared. The samples have been irradiated with neutrons (1 MeV) and protons (23 MeV and 23 GeV) corresponding to maximal fluences as expected for several positions of detector layers in the future tracker. Irradiations with protons of different energies have been performed to evaluate the energy dependence of the defect generation in oxygen rich material. All materials have been characterized before and after irradiations, and throughout an annealing treatment. The measurements performed on the structures include electrical sensor characterization, measurement of the collected charge injected with a beta source or laser light and bulk defect characterization. In this paper, a selection of results from the ongoing studies is presented.

  11. Radar interference blanking in radio astronomy using a Kalman tracker

    NASA Astrophysics Data System (ADS)

    Dong, W.; Jeffs, B. D.; Fisher, J. R.

    2005-06-01

    Radio astronomical observations of highly Doppler shifted spectral lines of neutral hydrogen and the hydroxyl molecule must often be made at frequencies allocated to pulsed air surveillance radar in the 1215-1350 MHz frequency range. The Green Bank telescope (GBT) and many other observatories must deal with these terrestrial signals. Even when strong radar fixed clutter echoes are removed, there are still weaker aircraft echoes present which can corrupt the data. We present an algorithm which improves aircraft echo blanking using a Kalman filter tracker to follow the path of a sequence of echoes observed on successive radar antenna sweeps. Aircraft tracks can be used to predict regions (in bearing and range) for the next expected echoes, even before they are detected. These data can then be blanked in real time without waiting for the pulse peak to arrive. Additionally, we briefly suggest an approach for a new Bayesian algorithm which combines tracker and pulse detector operations to enable more sensitive weak pulse detection. Examples are presented for Kalman tracking and radar transmission blanking using real observations at the GBT.

  12. Research and development of the laser tracker measurement system

    NASA Astrophysics Data System (ADS)

    Zhang, Z. L.; Zhou, W. H.; Lao, D. B.; Yuan, J.; Dong, D. F. F.; Ji, R. Y. Y.

    2013-01-01

    The working principle and system design of the laser tracker measurement system are introduced, as well as the key technologies and solutions in the implementation of the system. The design and implementation of the hardware and configuration of the software are mainly researched. The components of the hardware include distance measuring unit, angle measuring unit, tracking and servo control unit and electronic control unit. The distance measuring devices include the relative distance measuring device (IFM) and the absolute distance measuring device (ADM). The main component of the angle measuring device, the precision rotating stage, is mainly comprised of the precision axis and the encoders which are both set in the tracking head. The data processing unit, tracking and control unit and power supply unit are all set in the control box. The software module is comprised of the communication module, calibration and error compensation module, data analysis module, database management module, 3D display module and the man-machine interface module. The prototype of the laser tracker system has been accomplished and experiments have been carried out to verify the proposed strategies of the hardware and software modules. The experiments showed that the IFM distance measuring error is within 0.15mm, the ADM distance measuring error is within 3.5mm and the angle measuring error is within 3〞which demonstrates that the preliminary prototype can realize fundamental measurement tasks.

  13. Solar kinetics` photovoltaic concentrator module and tracker development

    SciTech Connect

    White, D.L.; Howell, B.

    1995-11-01

    Solar Kinetics, Inc., has been developing a point-focus concentrating photovoltaic module and tracker system under contract to Sandia National Laboratories. The primary focus of the contract was to achieve a module design that was manufacturable and passed Sandia`s environmental testing. Nine modules of two variations were assembled, tested, and characterized in Phase 1, and results of these tests were promising, with module efficiency approaching the theoretical limit achievable with the components used. The module efficiency was 11.9% at a solar irradiance of 850 W/m{sup 2} and an extrapolated cell temperature of 25{degrees}C. Improvements in module performance are anticipated as cell efficiencies meet their expectations. A 2-kW tracker and controller accommodating 20 modules was designed, built, installed, and operated at Solar Kinetics` test site. The drive used many commercially available components in an innovative arrangement to reduce cost and increase reliability. Backlash and bearing play were controlled by use of preloaded, low slip-stick, synthetic slide bearings. The controller design used a standard industrial programmable logic controller to perform ephemeris calculations, operate the actuators, and monitor encoders.

  14. The glutamate aspartate transporter (GLAST) mediates L-glutamate-stimulated ascorbate-release via swelling-activated anion channels in cultured neonatal rodent astrocytes.

    PubMed

    Lane, Darius J R; Lawen, Alfons

    2013-03-01

    Vitamin C (ascorbate) plays important neuroprotective and neuromodulatory roles in the mammalian brain. Astrocytes are crucially involved in brain ascorbate homeostasis and may assist in regenerating extracellular ascorbate from its oxidised forms. Ascorbate accumulated by astrocytes can be released rapidly by a process that is stimulated by the excitatory amino acid, L-glutamate. This process is thought to be neuroprotective against excitotoxicity. Although of potential clinical interest, the mechanism of this stimulated ascorbate-release remains unknown. Here, we report that primary cultures of mouse and rat astrocytes release ascorbate following initial uptake of dehydroascorbate and accumulation of intracellular ascorbate. Ascorbate-release was not due to cellular lysis, as assessed by cellular release of the cytosolic enzyme lactate dehydrogenase, and was stimulated by L-glutamate and L-aspartate, but not the non-excitatory amino acid L-glutamine. This stimulation was due to glutamate-induced cellular swelling, as it was both attenuated by hypertonic and emulated by hypotonic media. Glutamate-stimulated ascorbate-release was also sensitive to inhibitors of volume-sensitive anion channels, suggesting that the latter may provide the conduit for ascorbate efflux. Glutamate-stimulated ascorbate-release was not recapitulated by selective agonists of either ionotropic or group I metabotropic glutamate receptors, but was completely blocked by either of two compounds, TFB-TBOA and UCPH-101, which non-selectively and selectively inhibit the glial Na(+)-dependent excitatory amino acid transporter, GLAST, respectively. These results suggest that an impairment of astrocytic ascorbate-release may exacerbate neuronal dysfunction in neurodegenerative disorders and acute brain injury in which excitotoxicity and/or GLAST deregulation have been implicated. PMID:22886112

  15. LAT Software Induced Savings on Medical Costs of Alcohol Addicts' Care - Results from a Matched-Pairs Case-Control Study

    PubMed Central

    Jakovljevic, Mihajlo; Jovanovic, Mirjana; Rancic, Nemanja; Vyssoki, Benjamin; Djordjevic, Natasa

    2014-01-01

    Lesch Alcoholism Typology (LAT) is one of the most widely used clinical typologies of alcohol addiction. Study tested whether introduction of LAT software in clinical practice leaded to improved outcomes and reduced costs. Retrospective matched-pairs case-control cost comparison study was conducted at the Regional Addiction Center of the University Clinic in Serbia involving 250 patients during the four-year period. Mean relapse frequency followed by outpatient detoxification was 0.42±0.90 vs. 0.70±1.66 (LAT/non-LAT; p = 0.267). Adding relapses after inpatient treatment total mean-number of relapses per patient was 0.70±1.74 vs. 0.97±1.89 (LAT/non-LAT; p = 0.201). However, these relapse frequency differentials were not statistically significant. Total hospital costs of Psychiatry clinic based non-LAT addicts' care (€54,660) were significantly reduced to €36,569 after initiation of LAT. Mean total cost per patient was reduced almost by half after initiation of LAT based treatment: €331±381 vs. €626±795 (LAT/non-LAT; p = 0.001). Mean cost of single psychiatry clinic admission among non-LAT treatment group was €320±330 (CI 95% 262–378) and among LAT €197±165 (CI 95% 168–226) (p = 0.019). Mean LAT software induced net savings on psychiatric care costs were €144 per patient. Total net savings on hospital care including F10 associated somatic co-morbidities amounted to €295 per patient. More sensitive diagnostic assessment and sub-type specific pharmacotherapy and psychotherapy following implementation of LAT software lead to significant savings on costs of hospital care. PMID:25379730

  16. Fermi LAT Gamma-ray Observations of IceCube-160731

    NASA Astrophysics Data System (ADS)

    Cheung, C. C.; Toomey, M. W.; Kocevski, D.; Buson, S.

    2016-08-01

    We report follow-up of the extremely high-energy (EHE) IceCube-160731 neutrino event (AMON GCN notice; http://gcn.gsfc.nasa.gov/notices_amon/6888376_128290.amon) with all-sky survey data from the Large Area Telescope (LAT), on board the Fermi Gamma-ray Space Telescope.

  17. 2FHL: The Second Catalog of Hard Fermi-LAT Sources

    NASA Astrophysics Data System (ADS)

    Ackermann, M.; Ajello, M.; Atwood, W. B.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Becerra Gonzalez, J.; Bellazzini, R.; Bissaldi, E.; Blandford, R. D.; Bloom, E. D.; Bonino, R.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caputo, R.; Caragiulo, M.; Caraveo, P. A.; Cavazzuti, E.; Cecchi, C.; Charles, E.; Chekhtman, A.; Cheung, C. C.; Chiang, J.; Chiaro, G.; Ciprini, S.; Cohen, J. M.; Cohen-Tanugi, J.; Cominsky, L. R.; Conrad, J.; Cuoco, A.; Cutini, S.; D'Ammando, F.; de Angelis, A.; de Palma, F.; Desiante, R.; Di Mauro, M.; Di Venere, L.; Domínguez, A.; Drell, P. S.; Favuzzi, C.; Fegan, S. J.; Ferrara, E. C.; Focke, W. B.; Fortin, P.; Franckowiak, A.; Fukazawa, Y.; Funk, S.; Furniss, A. K.; Fusco, P.; Gargano, F.; Gasparrini, D.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Grondin, M.-H.; Guillemot, L.; Guiriec, S.; Harding, A. K.; Hays, E.; Hewitt, J. W.; Hill, A. B.; Horan, D.; Iafrate, G.; Hartmann, Dieter; Jogler, T.; Jóhannesson, G.; Johnson, A. S.; Kamae, T.; Kataoka, J.; Knödlseder, J.; Kuss, M.; La Mura, G.; Larsson, S.; Latronico, L.; Lemoine-Goumard, M.; Li, J.; Li, L.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Madejski, G. M.; Maldera, S.; Manfreda, A.; Mayer, M.; Mazziotta, M. N.; Michelson, P. F.; Mirabal, N.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nuss, E.; Ohsugi, T.; Omodei, N.; Orienti, M.; Orlando, E.; Ormes, J. F.; Paneque, D.; Perkins, J. S.; Pesce-Rollins, M.; Petrosian, V.; Piron, F.; Pivato, G.; Porter, T. A.; Rainò, S.; Rando, R.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Reposeur, T.; Romani, R. W.; Sánchez-Conde, M.; Saz Parkinson, P. M.; Schmid, J.; Schulz, A.; Sgrò, C.; Siskind, E. J.; Spada, F.; Spandre, G.; Spinelli, P.; Suson, D. J.; Tajima, H.; Takahashi, H.; Takahashi, M.; Takahashi, T.; Thayer, J. B.; Thompson, D. J.; Tibaldo, L.; Torres, D. F.; Tosti, G.; Troja, E.; Vianello, G.; Wood, K. S.; Wood, M.; Yassine, M.; Zaharijas, G.; Zimmer, S.

    2016-01-01

    We present a catalog of sources detected above 50 GeV by the Fermi-Large Area Telescope (LAT) in 80 months of data. The newly delivered Pass 8 event-level analysis allows the detection and characterization of sources in the 50 GeV-2 TeV energy range. In this energy band, Fermi-LAT has detected 360 sources, which constitute the second catalog of hard Fermi-LAT sources (2FHL). The improved angular resolution enables the precise localization of point sources (˜1.‧7 radius at 68% C. L.) and the detection and characterization of spatially extended sources. We find that 86% of the sources can be associated with counterparts at other wavelengths, of which the majority (75%) are active galactic nuclei and the rest (11%) are Galactic sources. Only 25% of the 2FHL sources have been previously detected by Cherenkov telescopes, implying that the 2FHL provides a reservoir of candidates to be followed up at very high energies. This work closes the energy gap between the observations performed at GeV energies by Fermi-LAT on orbit and the observations performed at higher energies by Cherenkov telescopes from the ground.

  18. VizieR Online Data Catalog: Fermi LAT third source catalog (3FGL) (Acero+, 2015)

    NASA Astrophysics Data System (ADS)

    Acero, F.; Ackermann, M.; Ajello, M.; Albert, A.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Belfiore, A.; Bellazzini, R.; Bissaldi, E.; Blandford, R. D.; Bloom, E. D.; Bogart, J. R.; Bonino, R.; Bottacini, E.; Bregeon, J.; Britto, R. J.; Bruel, P.; Buehler, R.; Burnett, T. H.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caputo, R.; Caragiulo, M.; Caraveo, P. A.; Casandjian, J. M.; Cavazzuti, E.; Charles, E.; Chaves, R. C. G.; Chekhtman, A.; Cheung, C. C.; Chiang, J.; Chiaro, G.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Cominsky, L. R.; Conrad, J.; Cutini, S.; D'Ammando, F.; de Angelis, A.; Deklotz, M.; de Palma, F.; Desiante, R.; Digel, S. W.; di Venere, L.; Drell, P. S.; Dubois, R.; Dumora, D.; Favuzzi, C.; Fegan, S. J.; Ferrara, E. C.; Finke, J.; Franckowiak, A.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Giebels, B.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Grondin, M.-H.; Grove, J. E.; Guillemot, L.; Guiriec, S.; Hadasch, D.; Harding, A. K.; Hays, E.; Hewitt, J. W.; Hill, A. B.; Horan, D.; Iafrate, G.; Jogler, T.; Johannesson, G.; Johnson, R. P.; Johnson, A. S.; Johnson, T. J.; Johnson, W. N.; Kamae, T.; Kataoka, J.; Katsuta, J.; Kuss, M.; La Mura, G.; Landriu, D.; Larsson, S.; Latronico, L.; Lemoine-Goumard, M.; Li, J.; Li, L.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Madejski, G. M.; Massaro, F.; Mayer, M.; Mazziotta, M. N.; McEnery, J. E.; Michelson, P. F.; Mirabal, N.; Mizuno, T.; Moiseev, A. A.; Mongelli, M.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nuss, E.; Ohno, M.; Ohsugi, T.; Omodei, N.; Orienti, M.; Orlando, E.; Ormes, J. F.; Paneque, D.; Panetta, J. H.; Perkins, J. S.; Pesce-Rollins, M.; Piron, F.; Pivato, G.; Porter, T. A.; Racusin, J. L.; Rando, R.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Reposeur, T.; Rochester, L. S.; Romani, R. W.; Salvetti, D.; Sanchez-Conde, M.; Saz Parkinson, P. M.; Schulz, A.; Siskind, E. J.; Smith, D. A.; Spada, F.; Spandre, G.; Spinelli, P.; Stephens, T. E.; Strong, A. W.; Suson, D. J.; Takahashi, H.; Takahashi, T.; Tanaka, Y.; Thayer J. G, .; Thayer, J. B.; Thompson, D. J.; Tibaldo, L.; Tibolla, O.; Torres, D. F.; Torresi, E.; Tosti, G.; Troja, E.; van Klaveren, B.; Vianello, G.; Winer, B. L.; Wood, K. S.; Wood, M.; Zimmer, S.

    2015-08-01

    The data for the 3FGL catalog were taken during the period from 2008 August 4 (15:43 UTC) to 2012 July 31 (22:46 UTC), to covering close to 4yr. The LAT detects γ-rays in the energy range from 20MeV to more than 300GeV. (3 data files).

  19. Fermi-LAT Gamma-Ray Bursts and Insights from Swift

    NASA Technical Reports Server (NTRS)

    Racusin, Judith L.

    2010-01-01

    A new revolution in Gamma-ray Burst (GRB) observations and theory has begun over the last two years since the launch of the Fermi Gamma-ray Space Telescope. The new window into high energy gamma-rays opened by the Fermi-Large Area Telescope (LAT) is providing insight into prompt emission mechanisms and possibly also afterglow physics. The LAT detected GRBs appear to be a new unique subset of extremely energetic and bright bursts compared to the large sample detected by Swift over the last 6 years. In this talk, I will discuss the context and recent discoveries from these LAT GRBs and the large database of broadband observations collected by the Swift X-ray Telescope (XRT) and UV/Optical Telescope (UVOT). Through comparisons between the GRBs detected by Swift-BAT, G8M, and LAT, we can learn about the unique characteristics, physical differences, and the relationships between each population. These population characteristics provide insight into the different physical parameters that contribute to the diversity of observational GRB properties.

  20. 2D/3D Visual Tracker for Rover Mast

    NASA Technical Reports Server (NTRS)

    Bajracharya, Max; Madison, Richard W.; Nesnas, Issa A.; Bandari, Esfandiar; Kunz, Clayton; Deans, Matt; Bualat, Maria

    2006-01-01

    A visual-tracker computer program controls an articulated mast on a Mars rover to keep a designated feature (a target) in view while the rover drives toward the target, avoiding obstacles. Several prior visual-tracker programs have been tested on rover platforms; most require very small and well-estimated motion between consecutive image frames a requirement that is not realistic for a rover on rough terrain. The present visual-tracker program is designed to handle large image motions that lead to significant changes in feature geometry and photometry between frames. When a point is selected in one of the images acquired from stereoscopic cameras on the mast, a stereo triangulation algorithm computes a three-dimensional (3D) location for the target. As the rover moves, its body-mounted cameras feed images to a visual-odometry algorithm, which tracks two-dimensional (2D) corner features and computes their old and new 3D locations. The algorithm rejects points, the 3D motions of which are inconsistent with a rigid-world constraint, and then computes the apparent change in the rover pose (i.e., translation and rotation). The mast pan and tilt angles needed to keep the target centered in the field-of-view of the cameras (thereby minimizing the area over which the 2D-tracking algorithm must operate) are computed from the estimated change in the rover pose, the 3D position of the target feature, and a model of kinematics of the mast. If the motion between the consecutive frames is still large (i.e., 3D tracking was unsuccessful), an adaptive view-based matching technique is applied to the new image. This technique uses correlation-based template matching, in which a feature template is scaled by the ratio between the depth in the original template and the depth of pixels in the new image. This is repeated over the entire search window and the best correlation results indicate the appropriate match. The program could be a core for building application programs for systems

  1. FERMI-LAT SEARCH FOR PULSAR WIND NEBULAE AROUND GAMMA-RAY PULSARS

    SciTech Connect

    Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Bloom, E. D.; Borgland, A. W.; Bouvier, A.; Buehler, R.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Brez, A.; Ballet, J.; Bastieri, D.; Buson, S.; Bonamente, E.; Brigida, M.; Bruel, P.

    2011-01-01

    The high sensitivity of the Fermi-LAT (Large Area Telescope) offers the first opportunity to study faint and extended GeV sources such as pulsar wind nebulae (PWNe). After one year of observation the LAT detected and identified three PWNe: the Crab Nebula, Vela-X, and the PWN inside MSH 15-52. In the meantime, the list of LAT detected pulsars increased steadily. These pulsars are characterized by high energy loss rates ( E-dot ) from {approx}3 x 10{sup 33} erg s{sup -1} to 5 x 10{sup 38} erg s{sup -1} and are therefore likely to power a PWN. This paper summarizes the search for PWNe in the off-pulse windows of 54 LAT-detected pulsars using 16 months of survey observations. Ten sources show significant emission, seven of these likely being of magnetospheric origin. The detection of significant emission in the off-pulse interval offers new constraints on the {gamma}-ray emitting regions in pulsar magnetospheres. The three other sources with significant emission are the Crab Nebula, Vela-X, and a new PWN candidate associated with the LAT pulsar PSR J1023-5746, coincident with the TeV source HESS J1023-575. We further explore the association between the HESS and the Fermi source by modeling its spectral energy distribution. Flux upper limits derived for the 44 remaining sources are used to provide new constraints on famous PWNe that have been detected at keV and/or TeV energies.

  2. Quantitative insight into the design of compounds recognized by the L-type amino acid transporter 1 (LAT1).

    PubMed

    Ylikangas, Henna; Malmioja, Kalle; Peura, Lauri; Gynther, Mikko; Nwachukwu, Emmanuel O; Leppänen, Jukka; Laine, Krista; Rautio, Jarkko; Lahtela-Kakkonen, Maija; Huttunen, Kristiina M; Poso, Antti

    2014-12-01

    L-Type amino acid transporter 1 (LAT1) is a transmembrane protein expressed abundantly at the blood-brain barrier (BBB), where it ensures the transport of hydrophobic acids from the blood to the brain. Due to its unique substrate specificity and high expression at the BBB, LAT1 is an intriguing target for carrier-mediated transport of drugs into the brain. In this study, a comparative molecular field analysis (CoMFA) model with considerable statistical quality (Q(2) =0.53, R(2) =0.75, Q(2) SE=0.77, R(2) SE=0.57) and good external predictivity (CCC=0.91) was generated. The model was used to guide the synthesis of eight new prodrugs whose affinity for LAT1 was tested by using an in situ rat brain perfusion technique. This resulted in the creation of a novel LAT1 prodrug with L-tryptophan as the promoiety; it also provided a better understanding of the molecular features of LAT1-targeted high-affinity prodrugs, as well as their promoiety and parent drug. The results obtained will be beneficial in the rational design of novel LAT1-binding prodrugs and other compounds that bind to LAT1. PMID:25205473

  3. The Large Area Telescope

    SciTech Connect

    Michelson, Peter F.; /KIPAC, Menlo Park /Stanford U., HEPL

    2007-11-13

    The Large Area Telescope (LAT), one of two instruments on the Gamma-ray Large Area Space Telescope (GLAST) mission, is an imaging, wide field-of-view, high-energy pair-conversion telescope, covering the energy range from {approx}20 MeV to more than 300 GeV. The LAT is being 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. The scientific objectives the LAT will address include resolving the high-energy gamma-ray sky and determining the nature of the unidentified gamma-ray sources and the origin of the apparently isotropic diffuse emission observed by EGRET; understanding the mechanisms of particle acceleration in celestial sources, including active galactic nuclei, pulsars, and supernovae remnants; studying the high-energy behavior of gamma-ray bursts and transients; using high-energy gamma-rays to probe the early universe to z {ge} 6; and probing the nature of dark matter. The components of the LAT include a precision silicon-strip detector tracker and a CsI(Tl) calorimeter, a segmented anticoincidence shield that covers the tracker array, and a programmable trigger and data acquisition system. 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 field-of-view and ensuring that nearly all pair-conversion showers initiated in the tracker will pass into the calorimeter for energy measurement. This paper includes a description of each of these LAT subsystems as well as a summary of the overall performance of the telescope.

  4. Adaptive Neural Star Tracker Calibration for Precision Spacecraft Pointing and Tracking

    NASA Technical Reports Server (NTRS)

    Bayard, David S.

    1996-01-01

    The Star Tracker is an essential sensor for precision pointing and tracking in most 3-axis stabilized spacecraft. In the interest (of) improving pointing performance by taking advantage of dramatic increases in flight computer power and memory anticipated over the next decade, this paper investigates the use of a neural net for adaptive in-flight calibration of the Star Tracker.

  5. Design of an upgraded D0 silicon microstrip tracker for Run IIb at the Tevatron

    SciTech Connect

    Hanagaki, K.; /Fermilab

    2004-01-01

    The D0 collaboration planned to upgrade the Silicon Tracker to withstand the radiation dose corresponding to above 2 fb{sup -1} of data. This new detector was designed to be functional up to at least 15 fb{sup -1}. The authors report on the design of the new Silicon Tracker with details of the innermost layer.

  6. Lightweight dual-axis tracker designs for dish-based HCPV

    NASA Astrophysics Data System (ADS)

    Angel, Roger; Cuerden, Brian; Whiteside, Andy

    2014-09-01

    Dish-based HCPV holds the promise of solar electricity at lower cost than for flat panel PV, provided that the dual-axis tracker cost can be minimized. Here we outline first and second generation lightweight tracker designs that include supports for a rectangular array of square dish mirrors and receivers located at their foci.

  7. Two-axis tracker for solar panels and the like

    SciTech Connect

    Liao, Henry H.

    2013-04-16

    A tracker including an outer post having elongated bore and a lower end mounted on a sub-structure, an inner pole rotatably received in the elongated bore, a lower bearing in the bore adjacent a lower end of the outer post and attached thereto to be constrained from lateral movement and mounted on the sub-structure such that a lower end of the inner pole rests on and is supported by the lower bearing, an upper bearing near an upper end of the outer post, a circumferential drive supported on the outer post for rotating the inner pole relative to the outer post, such that substantially a full weight of a load on the inner pole is directly transmitted to the sub-structure and lateral force and torque leverage are placed on a full length of the outer post by way of the upper and lower bearing.

  8. Performance of the CLAS12 Silicon Vertex Tracker modules

    SciTech Connect

    Antonioli, Mary Ann; Boiarinov, Serguie; Bonneau, Peter R.; Elouadrhiri, Latifa; Eng, Brian J.; Gotra, Yuri N.; Kurbatov, Evgeny O.; Leffel, Mindy A.; Mandal, Saptarshi; McMullen, Marc E.; Merkin, Mikhail M.; Raydo, Benjamin J.; Teachey, Robert W,; Tucker, Ross J.; Ungaro, Maurizio; Yegneswaran, Amrit S.; Ziegler, Veronique

    2013-12-01

    For the 12 GeV upgrade, the CLAS12 experiment has designed a Silicon Vertex Tracker (SVT) using single sided microstrip sensors fabricated by Hamamatsu. The sensors have graded angle design to minimize dead areas and a readout pitch of 156{micro}m, with intermediate strip. Double sided SVT module hosts three daisy-chained sensors on each side with a full strip length of 33 cm. There are 512 channels per module read out by four Fermilab Silicon Strip Readout (FSSR2) chips featuring data driven architecture, mounted on a rigid-flex hybrid. Modules are assembled on the barrel using unique cantilevered geometry to minimize the amount of material in the tracking volume. Design and performance of the SVT modules are presented, focusing on results of electrical measurements.

  9. On-Orbit Performance of Autonomous Star Trackers

    NASA Technical Reports Server (NTRS)

    Airapetian, V.; Sedlak, J.; Hashmall, J.

    2001-01-01

    This paper presents the results of a performance study of the autonomous star trackers (ASTs) on the IMAGE and the EO-1 spacecraft. IMAGE is a spinning spacecraft without gyros or redundant precision attitude sensors, so the statistical properties of the AST are estimated simply by comparing the output observed quaternions with a rigid rotator model with constant angular momentum. The initial conditions are determined by a least-squares fit to minimize the AST residuals. An additional fit is used to remove the remaining systematic error and to obtain the inherent sensor noise. Gyro rate data are available for the EO-1 mission, so the AST noise statistics are obtained from the residuals after solving for an epoch attitude and gyro bias also using a least-squares method.

  10. DAMPE silicon tracker on-board data compression algorithm

    NASA Astrophysics Data System (ADS)

    Dong, Yi-Fan; Zhang, Fei; Qiao, Rui; Peng, Wen-Xi; Fan, Rui-Rui; Gong, Ke; Wu, Di; Wang, Huan-Yu

    2015-11-01

    The Dark Matter Particle Explorer (DAMPE) is an upcoming scientific satellite mission for high energy gamma-ray, electron and cosmic ray detection. The silicon tracker (STK) is a subdetector of the DAMPE payload. It has excellent position resolution (readout pitch of 242 μm), and measures the incident direction of particles as well as charge. The STK consists of 12 layers of Silicon Micro-strip Detector (SMD), equivalent to a total silicon area of 6.5 m2. The total number of readout channels of the STK is 73728, which leads to a huge amount of raw data to be processed. In this paper, we focus on the on-board data compression algorithm and procedure in the STK, and show the results of initial verification by cosmic-ray measurements. Supported by Strategic Priority Research Program on Space Science of Chinese Academy of Sciences (XDA040402) and National Natural Science Foundation of China (1111403027)

  11. Performance of the CLAS12 Silicon Vertex Tracker modules

    NASA Astrophysics Data System (ADS)

    Antonioli, M. A.; Boiarinov, S.; Bonneau, P.; Elouadrhiri, L.; Eng, B.; Gotra, Y.; Kurbatov, E.; Leffel, M.; Mandal, S.; McMullen, M.; Merkin, M.; Raydo, B.; Teachey, W.; Tucker, R.; Ungaro, M.; Yegneswaran, A.; Ziegler, V.

    2013-12-01

    For the 12 GeV upgrade, the CLAS12 experiment has designed a Silicon Vertex Tracker (SVT) using single sided microstrip sensors fabricated by Hamamatsu. The sensors have graded angle design to minimize dead areas and a readout pitch of 156 μm, with intermediate strip. Double sided SVT module hosts three daisy-chained sensors on each side with a full strip length of 33 cm. There are 512 channels per module read out by four Fermilab Silicon Strip Readout (FSSR2) chips featuring data driven architecture, mounted on a rigid-flex hybrid. Modules are assembled on the barrel using unique cantilevered geometry to minimize the amount of material in the tracking volume. Design and performance of the SVT modules are presented, focusing on results of electrical measurements.

  12. Design and Performance of the Keck Angle Tracker

    NASA Technical Reports Server (NTRS)

    Crawford, Samuel L.; Ragland, S.; Booth, A.; Colavita, M. M.; Hovland, E.

    2006-01-01

    The Keck Angle Tracker (KAT) is a key subsystem in the NASA-funded Keck Interferometer at the Keck Observatory on the summit of Mauna Kea in Hawaii. KAT, which has been in operation since the achievement of first fringes in March 2001, senses the tilt of the stellar wavefront for each of the beams from the interferometer telescopes and provides tilt error signals to fast tip/tilt mirrors for high-bandwidth, wavefront tilt correction. In addition, KAT passes low-bandwidth, desaturation offsets to the adaptive optics system of the Keck telescopes to correct for slow pointing drifts. We present an overview of the instrument design and recent performance of KAT in support of the V2 science and nulling observing modes of the Keck Interferometer.

  13. Echo tracker/range finder for radars and sonars

    NASA Technical Reports Server (NTRS)

    Constantinides, N. J. (Inventor)

    1982-01-01

    An echo tracker/range finder or altimeter is described. The pulse repetition frequency (PFR) of a predetermined plurality of transmitted pulses is adjusted so that echo pulses received from a reflecting object are positioned between transmitted pulses and divided their interpulse time interval into two time intervals having a predetermined ratio with respect to each other. The invention described provides a means whereby the arrival time of a plurality of echo pulses is defined as the time at which a composite echo pulse formed of a sum of the individual echo pulses has the highest amplitude. The invention is applicable to radar systems, sonar systems, or any other kind of system in which pulses are transmitted and echoes received therefrom.

  14. Standard metrics for a plug-and-play tracker

    NASA Astrophysics Data System (ADS)

    Antonisse, Jim; Young, Darrell

    2012-06-01

    The Motion Imagery Standards Board (MISB) has previously established a metadata "micro-architecture" for standards-based tracking. The intent of this work is to facilitate both the collaborative development of competent tracking systems, and the potentially distributed and dispersed execution of tracker system components in real-world execution environments. The approach standardizes a set of five quasi-sequential modules in image-based tracking. However, in order to make the plug-and-play architecture truly useful we need metrics associated with each module (so that, for instance, a researcher who "plugs in" a new component can ascertain whether he/she did better or worse with the component). This paper proposes the choice of a new, unifying set of metrics based on an informationtheoretic approach to tracking, which the MISB is nominating as DoD/IC/NATO standards.

  15. Tail Catcher Muon Tracker For The CALICE Test Beam

    SciTech Connect

    Dyshkant, Alexander

    2006-10-27

    Results on the construction and commissioning of the CALICE Tail-catcher/Muon Tracker (TCMT) are presented. The {approx}1 m3 prototype uses extruded scintillating strips mated to silicon-photomultipliers and is located behind the CALICE hadron calorimeter. The TCMT will provide a snapshot of the tail end of hadron showers, which is crucial to the validation of hadronic Monte Carlo. It will also serve as a prototype muon system for any Linear Collider Detector (ILC) and will facilitate studies of muon tracking and identification within the particle flow reconstruction framework. Additionally, the TCMT will provide valuable practical experience with hadronic leakage and punch-through from thin calorimeters, as are envisaged for the ILC detector, and the impact of the coil in correcting for this leakage.

  16. The Tevatron tune tracker pll - theory, implementation and measurements

    SciTech Connect

    Tan, Cheng-Yang; /Fermilab

    2004-12-01

    The Tevatron tune tracker is based on the idea that the transverse phase response of the beam can be measured quickly and accurately enough to allow us to track the betatron tune with a phase locked loop (PLL). The goal of this paper is to show the progress of the PLL project at Fermilab. We will divide this paper into three parts: theory, implementation and measurements. In the theory section, we will use a simple linear model to show that our design will track the betatron tune under conditions that occur in the Tevatron. In the implementation section we will break down and examine each part of the PLL and in some cases calculate the actual PLL parameters used in our system from beam measurements. And finally in the measurements section we will show the results of the PLL performance.

  17. Higher throughput high resolution multi-worm tracker

    NASA Astrophysics Data System (ADS)

    Javer, Avelino; Li, Kezhi; Gyenes, Bertalan; Brown, Andre; Behavioural Genomics Team

    2015-03-01

    We have developed a high throughput imaging system for tracking multiple nematode worms at high resolution. The tracker consists of 6 cameras mounted on a motorized gantry so that up to 48 plates (each with approximately 30 worms) can be imaged without user intervention. To deal with the high data rate of the cameras we use real time processing to find worms and only save the immediately surrounding pixels. The system is also equipped with automatic oxygen and carbon dioxide control for observing stimulus response behaviour. We will describe the design and performance of the new system, some of the challenges of truly high throughput behaviour recording, and report preliminary results on inter-individual variation in behaviour as well as a quantitative analysis of C. elegans response to hypoxia, oxygen reperfusion, and carbon dioxide. Funding provided by the Medical Research Council.

  18. Circumnutation Tracker: novel software for investigation of circumnutation

    PubMed Central

    2014-01-01

    Background An endogenous, helical plant organ movement named circumnutation is ubiquitous in the plant kingdom. Plant shoots, stems, tendrils, leaves, and roots commonly circumnutate but their appearance is still poorly described. To support such investigations, novel software Circumnutation Tracker (CT) for spatial-temporal analysis of circumnutation has been developed. Results CT works on time-lapse video and collected circumnutation parameters: period, length, rate, shape, angle, and clockwise- and counterclockwise directions. The CT combines a filtering algorithm with a graph-based method to describe the parameters of circumnutation. The parameters of circumnutation of Helianthus annuus hypocotyls and the relationship between cotyledon arrangement and circumnutation geometry are presented here to demonstrate the CT options. Conclusions We have established that CT facilitates and accelerates analysis of circumnutation. In combination with the physiological, molecular, and genetic methods, this software may be a powerful tool also for investigations of gravitropism, biological clock, and membrane transport, i.e. processes involved in the mechanism of circumnutation.

  19. Articulated Arm Coordinate Measuring Machine Calibration by Laser Tracker Multilateration

    PubMed Central

    Majarena, Ana C.; Brau, Agustín; Velázquez, Jesús

    2014-01-01

    A new procedure for the calibration of an articulated arm coordinate measuring machine (AACMM) is presented in this paper. First, a self-calibration algorithm of four laser trackers (LTs) is developed. The spatial localization of a retroreflector target, placed in different positions within the workspace, is determined by means of a geometric multilateration system constructed from the four LTs. Next, a nonlinear optimization algorithm for the identification procedure of the AACMM is explained. An objective function based on Euclidean distances and standard deviations is developed. This function is obtained from the captured nominal data (given by the LTs used as a gauge instrument) and the data obtained by the AACMM and compares the measured and calculated coordinates of the target to obtain the identified model parameters that minimize this difference. Finally, results show that the procedure presented, using the measurements of the LTs as a gauge instrument, is very effective by improving the AACMM precision. PMID:24688418

  20. A precision star tracker utilizing advanced techniques and materials

    NASA Technical Reports Server (NTRS)

    Gates, R. F.; Mcaloon, K. J.

    1976-01-01

    An image dissector star tracker has been developed which operates in the photon counting mode making it possible to utilize all digital electronics. A unique pulse processing circuit allows bright stars to be tracked as well as dim stars. Thermal mechanical stability has been greatly enhanced by fabricating a housing with graphite/epoxy composite material with a linear coefficient of thermal expansion near zero. Test results indicate the +10 Mv stars can be acquired and tracked, while position variation with star intensity is less than 2 arc seconds from 2.5 Mv to +10 Mv. The noise equivalent angle for a +8 Mv star is 3 arc seconds. Polynominal correction for remaining cross-coupling and nonlinearity reduced error over total 1 x 1 deg field to 1.5 arc seconds.