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Sample records for glast lat tracker

  1. Environmental tests of the flight GLAST LAT tracker towers

    NASA Astrophysics Data System (ADS)

    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.; Fusco, P.; Gargano, F.; Germani, S.; Giglietto, N.; Giordano, F.; Goodman, J.; Himel, T.; Hirayama, M.; Johnson, R. P.; Katagiri, H.; Kataoka, J.; Kawai, N.; Kroeger, W.; Ku, J.; Kuss, M.; Latronico, L.; Longo, F.; Loparco, F.; Lubrano, P.; Marangelli, B.; Marcucci, F.; Marchetti, M.; Massai, M. M.; Mazziotta, M. N.; Minori, M.; Minuti, M.; Mirizzi, N.; Mongelli, M.; Monte, C.; Morselli, A.; Nelson, D.; Nordby, M.; Omodei, N.; Pepe, M.; Pesce-Rollins, M.; Rainò, S.; Rando, R.; Razzano, M.; Rich, D.; Scolieri, G.; Sgrò, C.; Spandre, G.; Spinelli, P.; Sugizaki, M.; Takahashi, H.; Tenze, A.; Young, C.

    2008-01-01

    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 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Novel Technique for Monitoring the Performance of the LAT Instrument on Board the GLAST Satellite

    SciTech Connect

    Paneque, D.; Borgland, A.; Bovier, A.; Bloom, E.; Edmonds, Y.; Funk, S.; Godfrey, G.; Rando, R.; Wai, L.; Wang, P.

    2007-06-13

    The Gamma-ray Large Area Space Telescope (GLAST) is an observatory designed to perform gamma-ray astronomy in the energy range 20 MeV to 300 GeV, with supporting measurements for gamma-ray bursts from 10 keV to 25 MeV. GLAST will be launched at the end of 2007, opening a new and important window on a wide variety of high energy astrophysical phenomena . The main instrument of GLAST is the Large Area Telescope (LAT), which provides break-through high-energy measurements using techniques typically used in particle detectors for collider experiments. The LAT consists of 16 identical towers in a four-by-four grid, each one containing a pair conversion tracker and a hodoscopic crystal calorimeter, all covered by a segmented plastic scintillator anti-coincidence shield. The scientific return of the instrument depends very much on how accurately we know its performance, and how well we can monitor it and correct potential problems promptly. We report on a novel technique that we are developing to help in the characterization and monitoring of LAT by using the power of classification trees to pinpoint in a short time potential problems in the recorded data. The same technique could also be used to evaluate the effect on the overall LAT performance produced by potential instrumental problems.

  12. The Capabilities of the GLAST LAT for Blazar Variability Studies

    NASA Technical Reports Server (NTRS)

    McEnery, Julie

    2008-01-01

    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. 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 Silicon Tracker of the Beam Test Engineering Model of the GLAST Large Area Telescope

    SciTech Connect

    do Couto e Silva, Eduardo

    2000-06-01

    The silicon tracker for the engineering model of the GLAST Large Area Telescope(LAT) has at least two unique features: it employs self triggering readout electronics, dissipating less than 200 mu-W per channel and to date represents the largest surface of silicon microstrip detectors assembled in a tracker (2.7 m{sup 2}). It demonstrates the feasibility of employing this technology for satellite based experiments, in which low power consumption, large effective areas and high reliability are required. This note describes the construction of this silicon tracker, which was installed in a beam test of positrons, hadrons and tagged photons at SLAC in December of 1999 and January of 2000.

  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. Construction, Test And Calibration of the GLAST Silicon Tracker

    SciTech Connect

    Sgro, C.; Atwood, W.B.; Baldini, L.; Barbiellini, G.; Bellazzini, R.; Belli, F.; Bonamente, E.; Borden, T.; Bregeon, J.; 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.; /INFN, Pisa /Pisa U. /UC, Santa Cruz /INFN, Trieste /Rome U.,Tor Vergata /SLAC /INFN, Bari /Bari U. /INFN, Perugia /Perugia U. /Udine U. /Hiroshima U. /Maryland U., JCA /Tokyo Inst. Tech. /JAXA, Sagamihara /INFN, Padua /Padua U. /Pisa, Scuola Normale Superiore /NASA, Goddard

    2009-06-05

    The Gamma-ray Large Area Space Telescope represents a great advance in space application of silicon detectors. With a surface of 80 m{sup 2} and about 1 M readout channels it is the largest silicon tracker ever built for a space experiment. GLAST is an astro-particle mission that will study the mostly unexplored, high energy (20 MeV-300 GeV) spectrum coming from active sources or diffused in the Universe. The detector integration and test phase is complete. The full instrument underwent environmental testing and the spacecraft integration phase has just started: the launch is foreseen in late 2007. In the meanwhile the spare modules are being used for instrument calibration and performance verification employing the CERN accelerator complex. A Calibration Unit has been exposed to photon, electron and hadron beams from a few GeV up to 300 GeV. We report on the status of the instrument and on the calibration campaign.

  18. 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).

  19. 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.

  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. 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.

  2. Measuring 10-1000 GeV Cosmic Ray Electrons with GLAST/LAT

    SciTech Connect

    Moiseev, Alexander A.; Ormes, Jonathan F.; Moskalenko, Igor V.

    2007-07-16

    We present here the capabilities of the GLAST Large Area Telescope to detect cosmic ray high-energy (HE) electrons in the energy range from 10 GeV to 1 TeV. We also discuss the science topics that can be investigated with HE electron data and quantify the results with LAT instrument simulations. The science topics include CR propagation, calibration of the IC gamma-ray model, testing hypotheses regarding the origin of HE energy cosmic-ray electrons, searching for any signature of Kaluza Klein Dark Matter annihilation, and measuring the HE electron anisotropy. We expect to detect {approx} 10{sup 7} electrons above 20 GeV per year of LAT operation.

  3. 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.

  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. Modern Statistical Methods for GLAST Event Analysis

    SciTech Connect

    Morris, Robin D.; Cohen-Tanugi, Johann; /SLAC /KIPAC, Menlo Park

    2007-04-10

    We describe a statistical reconstruction methodology for the GLAST LAT. The methodology incorporates in detail the statistics of the interactions of photons and charged particles with the tungsten layers in the LAT, and uses the scattering distributions to compute the full probability distribution over the energy and direction of the incident photons. It uses model selection methods to estimate the probabilities of the possible geometrical configurations of the particles produced in the detector, and numerical marginalization over the energy loss and scattering angles at each layer. Preliminary results show that it can improve on the tracker-only energy estimates for muons and electrons incident on the LAT.

  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. The GLAST Gamma-Ray Observatory

    SciTech Connect

    Latronico, L.

    2004-10-27

    GLAST is a space mission that will observe the gamma-ray sky between 20MeV and 1TeV with unprecedented resolution and sensitivity. The Large Area Telescope (LAT), the main instrument onboard the GLAST satellite, is built with state-of-the-art particle physics detectors, and combines a large area is-strip tracker-converter, that will measure direction of incoming photons to an imaging CsI e.m. calorimeter for measurements of photon energies; an outer, segmented Anti-Coincidence Detector will reject charged particle background. In this paper they give an overview of the many physics goals and potential reach of the GLAST observatory and describe in detail the instrument design and performance.

  10. GLAST Event Analysis An Examination of Events Recorded by the LAT Prototype Detector

    SciTech Connect

    Heimann, Jason

    2003-09-10

    The GLAST mission requires an orbiting satellite that will detect and analyze gamma rays from distant cosmic sources. A prototype particle detector (called the minitower) has been built: a scaled-down model similar to that which will be used in the satellite. previous experiments using the prototype detector have provided cosmic ray data taken at different signal thresholds. These data were processed with a track reconstruction algorithm that performed interpolations to approximate the path that each particle traveled. Using ROOT, they produced many graphs of the data to characterize the detector's response to cosmic rays and find correlations within the data. The coordinate system used in the data was verified against specifications and sensitive areas of the detector were measured. They have validated the geometry implementation of the detector using cosmic ray data, studied hit multiplicity and its angular dependence, and examined detector response under different threshold settings. A basic understanding of the detector's characteristics has been developed for future investigation of charge sharing between strips.

  11. 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.

  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. 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.

  14. 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.

  15. The GLAST Burst Monitor

    NASA Astrophysics Data System (ADS)

    Meegan, C.; Lichti, G.; Briggs, M.; Diehl, R.; Fishman, G.; Kippen, R.; Kouveliotou, C.; von Kienlin, A.; Paciesas, W.; Preece, R.; Schönfelder, V.

    2003-04-01

    The Gamma Ray Large Area Space Telescope (GLAST), scheduled for launch in 2006, comprises a Large Area Telescope (LAT) and a GLAST Burst Monitor (GBM). The LAT is a pair telescope with unprecedented sensitivity in the 20 MeV to 300 GeV energy range. The GLAST Burst Monitor consists of an array of NaI and BGO scintillation detectors operating in the 10 keV to 25 MeV range and covering a wide field of view. 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 repointing the spacecraft to observe delayed emission from bursts outside the LAT field of view.

  16. 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.

  17. 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.

  18. 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.

  19. Prospects for GLAST

    NASA Technical Reports Server (NTRS)

    McEnery, Julie

    2006-01-01

    The Gamma-ray Large Area Space Telescope (GLAST), scheduled for launch in late 007, is a satellite based observatory to study the high energy gamma-ray sky. There are two instruments on GLAST: the Large Area Telescope (LAT) which provides coverage from 20 MeV to over 300 GeV, and the GLAST Burst Monitor (GBM) which provides supportive observations of transients from 8 keV to 30 MeV. GLAST will provide well beyond those achieved by the highly successful EGRET instrument on the Compton Gamma-Ray Observatory, with dramatic improvements in sensitivity, angular resolution and energy range. The very large field of view will make it possible to observe approx. 20% of the sky at any instant, and the entire sky on timescale of a few hours. This talk includes a description of the instruments, the opportunities for guest investigators, and the mission status.

  20. 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.

  1. 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.

  2. The GLAST Burst Monitor

    NASA Astrophysics Data System (ADS)

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

    2004-09-01

    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 γ-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 γ-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 γ-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.

  3. 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.

  4. The GLAST burst monitor

    NASA Astrophysics Data System (ADS)

    von Kienlin, Andreas; Meegan, Charles A.; Lichti, Giselher G.; Bhat, Narayana P.; Briggs, Michael S.; Connaughton, Valerie; Diehl, Roland; Fishman, Gerald J.; Greiner, Jochen; Hoover, Andrew S.; Kippen, R. M.; Kouveliotou, Chryssa; Paciesas, William S.; Preece, Robert D.; Schönfelder, Volker; Steinle, Helmut; Wilson, Robert B.

    2004-10-01

    The next large NASA mission in the field of gamma-ray astronomy, GLAST, is scheduled for launch in 2007. Aside from the main instrument LAT (Large-Area Telescope), a gamma-ray telescope for the energy range between 20 MeV and > 100GeV, a secondary instrument, the GLAST burst monitor (GBM), is foreseen. With this monitor one of the key scientific objectives of the mission, the determination of the high-energy behaviour of gamma-ray bursts and transients can be ensured. Its task is to increase the detection rate of gamma-ray bursts for the LAT and to extend the energy range to lower energies (from ~10 keV to ~30 MeV). It will provide real-time burst locations over a wide FoV with sufficient accuracy to allow repointing the GLAST spacecraft. Time-resolved spectra of many bursts recorded with LAT and the burst monitor will allow the investigation of the relation between the keV and the MeV-GeV emission from GRBs over unprecedented seven decades of energy. This will help to advance our understanding of the mechanisms by which gamma-rays are generated in gamma-ray bursts

  5. 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.

  6. The GLAST mission

    NASA Technical Reports Server (NTRS)

    McEnery, Julie

    2006-01-01

    The Gamma-ray Large Area Space Telescope (GLAST) is a next-generation high-energy gamma-ray telescope for studying high energy gamma-ray emission from astrophysical sources. The main instrument is the Large Area Telescope (LAT) which operated in the energy band from 20 MeV to greater than 300 GeV. A second instrument, the Glast Burst Monitor to provide supportive observations of gamma-ray bursts at lower energies. The LAT is a solid state pair-conversion telescope which will have capabilities well beyond those achieved by the highly successful EGRET instrument on the Compton Gamma-ray Observatory. The sensitivity achieved on the entire sky after a single day's observation is similar to the point source sensitivity of EGRET for its entire mission. The large effective area will allow flares from AGN to be detected at much lower flux levels and on far shorter time intervals that has previously been possible from space. The very large field of view will make it possible to monitor approx. 20% of the sky at any instant, and the entire sky on timescale of a few hours. In this talk I will describe the design of the GLAST instruments and discuss their science capabilities.

  7. 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.

  8. 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.

  9. 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.

  10. The GLAST burst monitor (GBM)

    NASA Astrophysics Data System (ADS)

    Kippen, R. M.; Briggs, M. S.; Diehl, R.; Fishman, G. J.; Georgii, R. H.; Kouveliotou, C.; Lichti, G. G.; Meegan, C. A.; Paciesas, W. S.; Preece, R. D.; Schönfelder, V.; von Kienlin, A.

    2001-10-01

    The study of gamma-ray bursts (GRBs) is one of the primary scientific objectives of the Gamma-ray Large Area Space Telescope (GLAST) mission. With its high sensitivity to prompt and extended 20 MeV to 300 GeV burst emission, GLAST's Large Area Telescope (LAT) is expected to yield significant progress in the understanding of GRB physics. To tie these breakthrough high-energy measurements to the known properties of GRBs at lower energies, the GLAST Burst Monitor (GBM) will provide spectra and timing in the 10 keV to 25 MeV energy range. The GBM will also have the capability to quickly localize burst sources to ~15° over more than half the sky, allowing the LAT to re-point at particularly interesting bursts which occur outside its field of view. With combined LAT/GBM measurements GLAST will be able to characterize the spectral behavior of many bursts over nearly six decades in energy. This will allow the unknown aspects of high-energy burst emission to be explored in the context of well-known low-energy properties. In this paper, we present an overview of the GBM instrument, including its technical design, scientific goals, and expected performance. .

  11. The GLAST Large Area Telescope Detector Performance Monitoring

    SciTech Connect

    Borgland, A. W.; Charles, E.

    2007-07-12

    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 and Test and Commissioning of the instrument on ground.

  12. 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.

  13. The GLAST Large Area Telescope Detector Performance Monitoring

    NASA Astrophysics Data System (ADS)

    Borgland, A. W.; Charles, E.

    2007-07-01

    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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. The Status of GLAST CsI Calorimeter

    SciTech Connect

    Chekhtman, A.

    2003-09-18

    GLAST is a gamma-ray observatory for celestial sources in the energy range from 20 MeV to 300 GeV. This is NASA project with launch anticipated in 2006. The principal instrument of the GLAST mission is the Large Area Telescope (LAT), consisting of an Anti Coincidence Detector (ACD), a silicon-strip detector Tracker (TKR) and a hodoscopic CsI Calorimeter (CAL). It consists of 16 identical modules arranged in a 4 x 4 array. Each module has horizontal dimensions 38 x 38 cm{sup 2} and active thickness 8.5 radiation length. It contains 96 CsI (Tl) crystals arranged in 8 layers with 12 crystals per layer. The scintillation light is measured by PIN photodiodes mounted on both ends of each crystal. The sum of signals at the two ends of the crystal provides the energy measurement. The difference in these signals provides the position measurement along the crystal. The calorimeter was designed to meet the goals of good energy resolution (better than 10% for photon energies 100 MeV-100 GeV), position resolution of {approx} 1 mm for photon energies > 1 GeV, and a rejection factor of > 100 for charged cosmic rays, under limitations on calorimeter weight (95 kg per module) and power consumption (6 W per module). The Monte Carlo simulation and prototype beam test results confirm that proposed design meets the requirements. Calorimeter production is planned to start in 2003.

  2. 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.

  3. GLAST Mission Concept Study

    NASA Technical Reports Server (NTRS)

    Cominsky, Lynn R.

    2001-01-01

    Cominsky served as the chair of the GLAST Public Affairs Working Group during the mission concept study. The major accomplishments of this group, which were carried out under her direction include: (1) GLAST Outreach website; (2) Brochure for scientists; (3) Brochure for public; (4) Developed the five key science goal 'bullets' to explain GLAST to the public, as well as the motto used on the GLAST brochures 'Quest for the Ultimate Sources of Energy in the Universe'; (5) Defined the EPO program for GLAST for the proposal phase. Developed initial program outline and budget; and (6) Assisted in the development of the GLAST exhibit, which was used at several scientific conferences.

  4. 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.

  5. GRB Analysis Results from GLAST Data Challenge 2

    SciTech Connect

    Komin, Nukri

    2007-05-01

    The Gamma-ray Large Area Space Telescope (GLAST) will observe the gamma-ray sky in the MeV and GeV energy range. It will detect a number of gamma-ray bursts (GRBs) every year, depending on their emission at high energies, which is still unknown. GLAST will be the first instrument observing GRBs at energies above 20 GeV. A systematic study prior to launch, which is foreseen for 15 November 2007, was the GLAST Data Challenge 2 (DC 2). For GLAST DC 2 two month of data taking were simulated. Based on these simulations the GRB Working Group performed systematic studies of the performance of GLAST in observing GRBs. These studies included the spectral analysis of the prompt emission, a position fit of the GRB, and the search for prompt and afterglow emissions in the LAT data.

  6. GLAST User Support

    NASA Astrophysics Data System (ADS)

    Band, David L.; Science Support Center, GLAST

    2006-12-01

    The Gamma-ray Large Area Space Telescope (GLAST) mission will provide the user community with many scientific opportunities. The mission's interface with the user community is the GLAST Science Support Center (GSSC). Yearly guest investigator (GI) cycles will support research related to GLAST. After the first year GIs may propose pointed observations; however, as a consequence of the large field-of-view of GLAST's instruments, pointed observations will rarely have an advantage over the default survey mode. Data, analysis software and documentation will be provided through the GSSC website (http://glast.gsfc.nasa.gov/ssc/); the website also includes a library of scientific results, and a helpdesk.

  7. 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.

  8. 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/.

  9. Prospects for Observations of Microquasars with GLAST

    SciTech Connect

    Dubois, Richard; /SLAC

    2007-10-09

    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. This poster will present performance estimates with particular emphasis on how these apply to studies of microquasars. The LAT's scanning mode will provide unprecedented uniformity of sky coverage and permit measurements of light curves for any source. We will show results from recent detailed simulations that illustrate the potential of the LAT to observe microquasar variability and spectra, including source sensitivity and ability to detect orbital modulation.

  10. GLAST: GeV Astronomy in a Multiwavelength Context

    SciTech Connect

    Thompson, D

    2004-06-14

    The GLAST Large Area Telescope (LAT), successor to 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 gamma-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.

  11. Gamma Large Area Silicon Telescope (GLAST)

    SciTech Connect

    Godfrey, G.L.

    1993-11-01

    The recent discoveries and excitement generated by EGRET have prompted an investigation into modern technologies ultimately leading to the next generation space-based gamma ray telescope. The goal is to design a detector that will increase the data acquisition rate by almost two orders of magnitude beyond EGRET, while at the same time improving on the angular resolution, the energy measurement of reconstructed gamma rays, and the triggering capability of the instrument. The GLAST proposal is based on the assertion that silicon particle detectors are the technology of choice for space application: no consumables, no gas volume, robust (versus fragile), long lived, and self triggering. The GLAST detector is roughly modeled after EGRET in that a tracking module precedes a calorimeter. The GLAST Tracker has planes of thin radiatior interspersed with planes of crossed-strip (x,y) 300-{mu}m-pitch silicon detectors to measure the coordinates of converted electron-positron pairs. The gap between the layers ({approximately}5 cm) provides a lever arm in track fitting resulting in an angular resolution of 0.1{degree} at high energy (the low energy angular resolution at 100 MeV would be about 2{degree}, limited by multiple scattering). A possible GLAST calorimeter is made of a mosaic of Csl crystals of order 10 r.l. in depth, with silicon photodiodes readout. The increased depth of the GLAST calorimeter over EGRET`s extends the energy range to about 300 GeV.

  12. Expected Performance of the GLAST Burst Monitor

    NASA Technical Reports Server (NTRS)

    Meegan, Charles; Bhat, Narayana; Briggs, Michael; Connaughton, Valerie; Diehl, Roland; Fishman, Gerald; Greiner, Jochen; von Kienlin, Andreas; Kippen, R. Marc; Kouveliotou, Chryssa; hide

    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.

  13. 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.

  14. 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.

  15. Detecting the EBL attenuation of blazars with GLAST

    NASA Astrophysics Data System (ADS)

    Reyes, Luis C.

    The Large Area Telescope (LAT) on board GLAST (Gamma-ray Large Area Space Telescope) due for launch in late 2007 will study the gamma-ray sky in the energy range 20 MeV to >300 GeV. GLAST-LAT's improved sensitivity with respect to previous missions will increase the number of known gamma-ray blazars from about 100 to thousands, with redshifts up to z~3-5. Since g-rays with energy above 10 GeV interact via pair-production with photons from the Extragalactic Background Light (EBL), the systematic attenuation of GLAST-detected blazars as a function of redshift would constitute and effective and unique probe of the optical-UV EBL density and its evolution over cosmic history. Analysis techniques introduced in this dissertation make use of the large number of blazars detected by GLAST to study the collective behavior of their spectra as a function of redshift. These techniques are shown to offer powerful ways to help separate the common level of attenuation due to the EBL from the intrinsic peculiarities of individual blazars. The capability of GLAST to perform these measurements depends in great measure on the acceptance of the instrument to high energy g-rays ( E > 10 GeV), which in previous space-experiments has been drastically reduced due to backsplash self-veto. This dissertation includes a study of the backsplash effect as measured with flight-like detectors during a beam test of the LAT calibration unit. This analysis was used to verify the capabilities of the GLAST simulations tools to reproduce backsplash effects.

  16. 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.

  17. The Glast Burst Monitor

    NASA Astrophysics Data System (ADS)

    Meegan, C.; Fishman, G.; Kouveliotou, C.; Paciesas, W.; Kippen, R.; Briggs, M.; Preece, R.; Lichti, G.; von Kienlin, A.; Georgii, R.; Diehl, R.; Schöenfelder, V.

    2002-12-01

    The Gamma-Ray Large Area Space Telescope (GLAST) will include a secondary instrument to augment the observatory's capabilities for GRB studies. The GLAST Burst Monitor (GBM) will extend energy coverage from the main instrument's lower limit of ~ 20 MeV down to ~ 10 keV, and will provide an on-board burst trigger and approximate location. The instrument consists of twelve NaI detectors and two BGO detectors.

  18. 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.

  19. The Glast Burst Monitor

    NASA Technical Reports Server (NTRS)

    Meegan, Charles

    2000-01-01

    The Gamma-Ray Large Area Space Telescope (GLAST) will include a secondary instrument to augment the observatory's capabilities for GRB studies. The GLAST Burst Monitor (GBK is a collaboration between Marshall Space Flight Center, the University of Huntsville, Alabama, and the Max Plank Institute for Extraterrestrial Physics. The purpose of the GBM is to extend energy coverage below the main instrument's lower limit of about 20 MeV, and to provide an on-board burst trigger and approximate location. The instrument consists of twelve NaI detectors and two BGO detectors. This combination provides energy coverage from a few keV up to about 30 MeV.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. GLAST Mission Overview

    NASA Technical Reports Server (NTRS)

    Ritz, Steve

    2004-01-01

    The Gamma-ray Large Area Space Telescope, GLAST, is a satellite-based observatory under construction to measure the cosmic gamma-ray flux in the energy range 20 MeV to >300 GeV, with supporting measurements for gamma-ray bursts from 10 keV to 25 MeV. With its launch in 2007, GLAST will open a new and important window on a wide variety of high energy phenomena, including 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, Lorentz invariance violation, and exotic relics from the Big Bang. In addition to the science opportunities, this talk will include a brief description of the instruments, the collaboration of particle physicists and high energy astrophysicist, the mission status, and the opportunities and support for guest observers.

  6. GLAST Mission Overview

    NASA Technical Reports Server (NTRS)

    Ritz, Steve

    2004-01-01

    The Gamma-ray Large Area Space Telescope, GLAST, is a satellite-based observatory under construction to measure the cosmic gamma-ray flux in the energy range 20 MeV to >300 GeV, with supporting measurements for gamma-ray bursts from 10 keV to 25 MeV. With its launch in 2007, GLAST will open a new and important window on a wide variety of high energy phenomena, including 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, Lorentz invariance violation, and exotic relics from the Big Bang. In addition to the science opportunities, this talk will include a brief description of the instruments, the collaboration of particle physicists and high energy astrophysicist, the mission status, and the opportunities and support for guest observers.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Gamma Ray Large Area Space Telescope (GLAST) Balloon Flight Data Handling Overview

    SciTech Connect

    Rochester, Leon S

    2002-09-25

    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.

  16. The GLAST Science Support Center

    NASA Astrophysics Data System (ADS)

    Shrader, Chris R.; Staff, GSSC

    2006-09-01

    The GLAST Science Support Center (GSSC) will serve as the primary interface between the GLAST mission and the scientific community. The GSSC will support the planning and scheduling of science observations, as well as establishing and maintaining a publicly accessible archive of all GLAST data products. Data analysis software and documentation will also be maintained and disseminated by the GSSC. In addition, the GSSC will administer the guest investigator program for NASA HQ and provide proposal preparation tools, documentation as well as technical and scientific support. We will describe our plans for each of these activities, as well as offering a preview of the forthcoming NASA Research Announcement (NRA) for the Cycle-1 GLAST Guest Investigator Program.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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

  9. Swift and GLAST Cooperative Efforts

    NASA Technical Reports Server (NTRS)

    Thompson, D. J.

    2007-01-01

    Because gamma-ray astrophysics depends in many ways on multiwavelength studies, the Gamma-ray Large Area Space Telescope (GLAST) instrument teams are eagerly anticipating coordinated observations with the Swift observatory. Swift and GLAST combined cover most of twelve orders of magnitude in the electromagnetic spectrum, offering numerous opportunities for cooperation. Three of the high-priority interests are: (1) gamma-ray burst studies; (2) broad-spectrum studies of blazars in both quiescent and flaring states; and (3) identification and detailed study of unidentified gamma-ray sources.

  10. Future GLAST Observations of SNRs and PWNe

    SciTech Connect

    Funk, S.; /SLAC

    2007-10-10

    Shell-type Supernova remnants (SNRs) have long been known to harbor a population of ultra-relativistic particles, accelerated in the Supernova shock wave by the mechanism of Diffusive shock acceleration. Pulsar Wind Nebulae (PWNe) - diffuse structures surrounding young pulsars - are also known to be a site of particle acceleration in the Galaxy. {gamma}-rays above 100 MeV provide a direct access to acceleration processes through the following channels: ultra-relativistic electrons emit {gamma}-radiation through Inverse Compton scattering in ubiquitous photon fields (such as CMBR), protons emit {gamma}-radiation through the decay of {pi}{sup 0}s, generated in hadronic interactions with Interstellar material such as gas clouds. The upcoming 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 so-far rather poorly investigated energy band to address important questions in our understanding of both shell-type SNRs and PWNe.

  11. The anti-coincidence detector for the GLAST large area telescope

    NASA Astrophysics Data System (ADS)

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

    2007-06-01

    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 LATs 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 four sides of the LAT tracking detector, requiring a total active area of ˜8.3 m2. The ACD detector utilizes plastic scintillator tiles with wavelength 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.

  12. 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.

  13. 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.

  14. LAT Observation of GRBs: Simulations and Sensitivity Studies

    SciTech Connect

    Omodei, Nicola; Norris, Jay; /Denver U.

    2007-10-22

    The GLAST Large Area Telescope (LAT) is the next generation satellite experiment for high-energy gamma-ray astronomy. It employs a pair conversion technique to record photons in the energy range from 20 MeV to more than 300 GeV. The LAT will follow the steps from its predecessor EGRET (1991-2000), and will explore the high-energy gamma-ray sky with unprecedented capabilities. The observation of Gamma-Ray Bursts is one of the main science goal of the LAT: in this contribution we compute an estimation of the LAT sensitivity to GRB, adopting a phenomenological description of GRBs, where the high-energy emission in GRB is obtained extrapolating the observed BATSE spectrum up to LAT energies. The effect of the cosmological attenuation is included. We use the BATSE current catalog to build up our statistics.

  15. LAT observation of GRBs: Simulations and Sensitivity studies

    SciTech Connect

    Omodei, Nicola; Norris, Jay

    2007-07-12

    The GLAST Large Area Telescope (LAT) is the next generation satellite experiment for high-energy gamma-ray astronomy. It employs a pair conversion technique to record photons in the energy range from 20 MeV to more than 300 GeV. The LAT will follow the steps from its predecessor EGRET (1991-2000), and will explore the high-energy gamma-ray sky with unprecedented capabilities. The observation of Gamma-Ray Bursts is one of the main science goal of the LAT: in this contribution we compute an estimation of the LAT sensitivity to GRB, adopting a phenomenological description of GRBs, where the high-energy emission in GRB is obtained extrapolating the observed BATSE spectrum up to LAT energies. The effect of the cosmological attenuation is included. We use the BATSE current catalog to build up our statistics.

  16. 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.

  17. The GLAST Burst Monitor (GBM)

    NASA Astrophysics Data System (ADS)

    Lichti, G. G.; Briggs, M. S.; Diehl, R.; Fishman, G.; Georgii, R.; Kippen, R. M.; Kouveliotou, C.; Meegan, C.; Paciesas, W.; Preece, R.; Schönfelder, V.; von Kienlin, A.

    The selection of the GLAST burst monitor (GBM) by NASA will allow the investigation of the relation between the keV and the MeV-GeV emission from γ-ray bursts. The GBM consists of 12 NaI and 2 BGO crystals allowing a continuous measurement of the energy spectra of γ-ray bursts from ˜ 5 keV to ˜ 30 MeV. One feature of the GBM is its high time resolution for time-resolved γ-ray spectroscopy. Moreover the arrangement of the NaI-crystals allows a rapid on-board location ( < 15°) of a γ-ray burst within a FoV of ˜ 8.6 sr. This position will be communicated to the main instrument of GLAST making follow-up observations at high energies possible.

  18. 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

  19. 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.

  20. GBM: a gamma-ray burst monitor for GLAST

    NASA Astrophysics Data System (ADS)

    Lichti, Giselher G.; Briggs, Michael S.; Diehl, Roland; Fishman, Gerald J.; Kippen, Richard M.; Kouveliotou, Chryssa; Meegan, Charles A.; Paciesas, William S.; Preece, Robert S.; Schoenfelder, Volker; von Kienlin, Andreas

    2003-03-01

    One of the scientific objectives of the GLAST mission is the study of gamma-ray bursts (GRBs) which will be measured by the Large-Area Telescope, the main instrument of GLAST, in the energy range from ~20 MeV to ~300 GeV. In order to extend the energy measurement towards lower energies a secondary instrument, the GLAST Burst Monitor (GBM) will measure GRBs from ~10 keV to ~25 MeV and will thus allow the investigation of the relation between the keV and the MeV-GeV emission from GRBs. The GBM consists of 12 circular NaI crystal discs and 2 cylindrical BGO crystals. The NaI crystals are optimized for gamma radiation from ~10 keV to ~1 MeV and the BGO crystals from ~150 keV to ~25 MeV. The NaI crystals are oriented in such a way that the measured relative counting rates allow a rapid determination of the position of a gamma-ray burst within a wide FoV of ~8.6 sr. This position will be communicated within seconds to the LAT which may then be reoriented to observe the long-lasting high-energy gamma-ray emission from GRBs. This will allow the exploration of the unknown aspects of the high-energy burst emission and their connection with the well-known low-energy emission. Another important feature of the GBM is its high time resolution of ~10 microseconds for time-resolved gamma-ray spectroscopy.

  1. 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.

  2. Pre-launch estimates for GLAST sensitivity to dark matter annihilation signals

    DOE PAGES

    Baltz, E. A.; Berenji, B.; Bertone, G.; ...

    2008-07-17

    Here, we investigate the sensitivity of the Gamma-ray Large Area Space Telescope (GLAST) to indirectly detect weakly interacting massive particles (WIMPs) through the γ-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 themore » 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. Lastly, 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.« less

  3. Pre-launch estimates for GLAST sensitivity to dark matter annihilation signals

    SciTech Connect

    Baltz, E. A.; Berenji, B.; Bertone, G.; Bergström, L.; Bloom, E.; Bringmann, T.; Chiang, J.; Cohen-Tanugi, J.; Conrad, J.; Edmonds, Y.; Edsjö, 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.; Sander, A. J.; Sellerholm, A.; Smith, P. D.; Strong, A. W.; Wai, L.; Wang, P.; Winer, B. L.

    2008-07-17

    Here, we investigate the sensitivity of the Gamma-ray Large Area Space Telescope (GLAST) to indirectly detect weakly interacting massive particles (WIMPs) through the γ-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. Lastly, 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.

  4. The role of GLAST in multiwavelength observations of bright TeV blazars

    NASA Astrophysics Data System (ADS)

    Stacy, J.G.; Collmar, W.; Strong, A.; Schönfelder, V.; Carramiñana, A.

    The TeV blazars Mrk 421, Mrk 501, PSK 2155-304 and 1ES1959+650 are among the brightest known blazars, yet the existing experimental set of data does not allow one to make unambiguous statements about the physical mechanisms responsible for the electromagnetic emission. The lack of sensitive coverage in the energy range 1 MeV to 500 GeV (up to 2004), and the scarce truly simultaneous data result in a big inter-model and intra-model degeneracy. The LAT instrument on board of the GLAST satellite, which will start operation in the fall 2007, aims to perform gamma-ray astronomy in the energy range 20 MeV to 300 GeV. The sensitivity of LAT is about 25 times better than its predecessor, EGRET. Together with the enhanced sensitivity of the current generationn of Imaging Air Cherenkov Telescopes (IACTs) in the energy range 100 GeV - 500 GeV, LAT observations offer unprecedented capabilities to study the high energy emission of these objects in both quiescent and flaring state. In the conference we will present the capabilities of the LAT instrument to study these objects, as well as the planned multiwavelength campaigns during the first year of GLAST operation.

  5. 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.

  6. The GLAST Education and Public Outreach Program

    NASA Astrophysics Data System (ADS)

    Plait, P.; Graves, T.; Silva, S.; Simonnet, A.; Spear, G.; Cominsky, L.

    2004-12-01

    The Gamma-Ray Large Area Space Telescope (GLAST), due to launch in 2007, is a NASA mission designed to observe gamma rays from the most energetic objects in the Universe. The NASA Education and Public Outreach (E/PO) Group at Sonoma State University is the lead institution for GLAST E/PO. Given the size of the mission itself, we have planned and are executing an ambitious outreach program, including 1) an educators guide with activities (and a beautiful poster) designed to bring the science of active galaxies into the classroom; 2) a series of classroom modules by TOPS Learning Systems, Inc. that uses the GLAST mission to teach logarithms, powers of ten, and the scale of the Universe; 3) a robotic telescope in Sonoma County, California to observe GLAST targets, aiding not only GLAST science but also teaching students how astronomers process astronomical data; 4) ten Educator Ambassadors: award-winning teachers who help the E/PO group develop, test, and disseminate educational products; 5) an interactive Virtual Visitor Center web site for the Stanford Linear Accelerator Center, featuring an interactive simulation of GLAST's main gamma ray detector, which is being built by the US Department of Energy, and institutions in Italy, Japan, France and Sweden; 6) a one-hour PBS NOVA television show about black holes; 7) an interactive web-based Space Mystery which teaches students about active galaxies; 8) a series of educator workshops across the country to train teachers how to use the GLAST products; 9) an educators guide based on the high-energy physics of supernovae; and 10) extensive assessment by external evaluators at WestEd. More educational materials and information about the GLAST E/PO program can be found at http://glast.sonoma.edu.

  7. Statistical Issues in High-Energy Gamma-Ray Astronomy for GLAST

    SciTech Connect

    Digel, S

    2004-04-06

    This paper describes the statistical issues involved in analyzing data from high-energy gamma-ray telescopes, at levels from event reconstruction to correlations of populations of astrophysical sources. Some motivation for attempting to do astronomy with high-energy gamma rays is also given, along with some of the constraints implied by operating the instrument in orbit. Specific attention is given to the Large Area Telescope (LAT) under development for launch in late 2006 on the Gamma-ray Large Area Space Telescope (GLAST) mission.

  8. 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.

  9. 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.

  10. 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.

  11. Searches for WIMP Annihilation with GLAST

    SciTech Connect

    Wai, L.; /SLAC

    2005-06-21

    We describe signatures for WIMP annihilation in the gamma ray sky which can be observed by the GLAST mission, scheduled for launch in 2007. We review the search regions, which range from galactic substructure in the Milky Way all the way out to cosmological sources.

  12. STATUS OF THE GLAST LARGE AREA TELESCOPE

    SciTech Connect

    Dubois, R

    2003-12-05

    The GLAST Large Area telescope is a modular 4 x 4 tower pair conversion telescope with field of view greater than 2 steradians and energy coverage from 20 MeV to 300 GeV. The observatory is scheduled for launch in September 2006. A status of the instrument construction is presented here.

  13. Tracker Studies

    DTIC Science & Technology

    1975-06-01

    ict public roenq IA, - x.’ nicn~ Unitnitod I ITT-EPL PROJECT REPORT NO. 278 CHAPEL BELL REPORT NO. 115 TRACKER STUDIES R. N. DeWitt SManager, Advanced...peak amplitude at the F layer. These values lead to a maximum rate of angular deviation I d dhl k2 dx 11[djma = Ak dt dxj max dt =10 k.1 (.004)2 kmŖ

  14. 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).

  15. Fermi LAT detection of a GeV flare from blazar B2 1520+31

    NASA Astrophysics Data System (ADS)

    Cutini, S.; Hays, E.

    2009-04-01

    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 B2 1520+31 (RA: 15 22 09.99 , Dec: +31 44 14.4 , J2000, A. J. Beasley et al. 2002, ApJS, 41, 13) since April 20, 2009.

  16. 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.

  17. XML for Detector Description at GLAST

    SciTech Connect

    Bogart, Joanne

    2002-04-30

    The problem of representing a detector in a form which is accessible to a variety of applications, allows retrieval of information in ways which are natural to those applications, and is maintainable has been vexing physicists for some time. Although invented to address an entirely different problem domain, the document markup meta-language XML is well-suited to detector description. This paper describes its use for a GLAST detector.

  18. XML for Detector Description at GLAST

    NASA Astrophysics Data System (ADS)

    Bogart, J.

    2002-04-01

    The problem of representing a detector in a form which is accessible to a variety of applications, allows retrieval of information in ways which are natural to those applications, and is maintainable has been vexing physicists for some time. Although invented to address an entirely different problem domain, the document markup meta-language XML is well-suited to detector description. This paper describes its use for a GLAST detector.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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)

  4. GLAST LARGE AREA TELESCOPE: DAILY SURVEY OF HIGH-ENERGY SKY

    SciTech Connect

    Kamae, T

    2003-12-12

    GLAST Large Area Telescope was proposed to NASA in 1999 as 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 w die range of astrophysics with 5-40 times higher sensitivity and extended energy coverage (20 MeV to 300 GeV) than EGRET. The instrument consists of 16 towers of e{sup +}e{sup -} pair tracker, 16 blocks of segmented electro-magnetic calorimeter, and a st of anti-coincidence 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 ({approx} 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.

  5. High-Latitude Molecular Clouds as Gamma-Ray Sources for GLAST

    SciTech Connect

    Torres, D.

    2005-01-28

    For about two decades, a population of relative small and nearby molecular clouds has been known to exist at high Galactic latitudes. Lying more than 10{sup o} from the Galactic plane, these clouds have typical distances of {approx}150 pc, angular sizes of {approx}1{sup o}, and masses of order tens of solar masses. These objects are passive sources of high-energy {gamma}-rays through cosmic ray-gas interactions. Using a new wide-angle CO survey of the northern sky, we show that typical high-latitude clouds are not bright enough in {gamma}-rays to have been detected by EGRET, but that of order 100 of them will be detectable by the Large Area Telescope (LAT) on GLAST. Thus, we predict a new steady population of {gamma}-ray sources at high Galactic latitudes, perhaps the most numerous after active galactic nuclei.

  6. 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.

  7. A gamma-ray burst monitor for GLAST

    NASA Astrophysics Data System (ADS)

    von Kienlin, A.; Briggs, M. S.; Diehl, R.; Fishman, G. J.; Georgii, R.; Kippen, R. M.; Kouveliotou, C.; Lichti, G. G.; Meegan, C. A.; Paciesas, W. S.; Preece, R. D.; Schönfelder, V.

    2001-09-01

    The Gamma-Ray Large-Area Space Telescope GLAST is the next NASA mission in the high-energy γ-ray regime (10 MeV to about 500 GeV), with launch anticipated in 2006 (Gehrels, 1999). Recently a design using silicon strips for the electron-positron pair tracking was selected for the main instrument. One of the key scientific objectives of the GLAST mission is to determine the high-energy behaviour of gamma-ray bursts and transients. The importance of studying bursts with GLAST has been emphasized by choosing a burst monitor as the secondary instrument on GLAST. A proposal to the NASA AO for such a burst monitor was submitted jointly by a collaboration between the Marshall Space-Flight Center/University of Alabama (both in Huntsville/Alabama) and the Max-Planck-Institut für extraterrestrische Physik in Garching. This GLAST Burst Monitor will complement the main instrument information about bursts in the energy range between 5 keV and 30 MeV. It will provide real-time burst locations over a wide FOV with sufficient accuracy to repoint the GLAST spacecraft. Time-resolved spectra of many bursts recorded with GLAST and the burst monitor will cover unprecedented 6 decades of energy. This will help to advance our understanding of the mechanisms by which gamma-rays are generated in gamma-ray bursts. Mid of March 2000 this proposal for GLAST's burst monitor has been selected.

  8. 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.

  9. 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.

  10. Cosmic Ray Electron Science with GLAST

    NASA Technical Reports Server (NTRS)

    Ormes, J. F.; Moiseev, Alexander

    2007-01-01

    Cosmic ray electrons at high energy carry information about their sources, their definition in local magnetic fields and their interactions with the photon fields through which they travel. The spectrum of the particles is affected by inverse Compton losses and synchrotron losses, the rates of which are proportional to the square of the particle's energy making the spectra very steep. However, GLAST will be able to make unique and very high statistics measurements of electrons from approx. 20 to approx. 700 GeV that will allow us to search for anisotropies in anival direction and spectral features associated with some dark matter candidates. Complementary information on electrons of still higher energy will be required to see effects of possible individual cosmic ray sources.

  11. Cosmic Ray Electron Science with GLAST

    SciTech Connect

    Ormes, J.F.; Moiseev, Alexander; /NASA, Goddard

    2007-10-17

    Cosmic ray electrons at high energy carry information about their sources, their diffusion in local magnetic fields and their interactions with the photon fields through which they travel. The spectrum of the particles is affected by inverse Compton losses and synchrotron losses, the rates of which are proportional to the square of the particle's energy making the spectra very steep. However, GLAST will be able to make unique and very high statistics measurements of electrons from {approx}20 to {approx}700 GeV that will allow us to search for anisotropies in arrival direction and spectral features associated with some dark matter candidates. Complementary information on electrons of still higher energy will be required to see effects of possible individual cosmic ray sources.

  12. 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.

  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. The Gamma-ray Large Area Space Telescope (GLAST): Instrument Technology Development

    NASA Astrophysics Data System (ADS)

    Michelson, Peter F.; GLAST Collaboration

    1999-04-01

    The Gamma-ray Large Area Space Telescope, GLAST, is a satellite-based experiment under development to measure the cosmic gamma-ray flux in the energy range from 20 MeV to 300 GeV. The primary telescope for the mission is a pair-conversion telescope. The telescope design includes a precision tracker/converter section based on silicon-strip detectors, a CsI scintillating crystal calorimeter arranged in a hodoscopic configuration, an anticoincidence shield that is an array of plastic scintillator tiles read out with waveshifting optical fibers, and a powerful distributed data acquisition and triggering system. The design and expected performance of the telescope are presented along with results obtained from a high-energy beam test of a prototype.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Testing Gravity with GLAST: GRBs Lensed by Primordial Black Holes

    NASA Astrophysics Data System (ADS)

    Klimek, Matthew; Keeton, C. R.

    2007-05-01

    In the Randall-Sundrum model of branework gravity, very low mass (<10-18 Msun) primordial black holes could persist to the present day. Keeton & Petters have calculated the gravitational lensing effects of such primordial braneworld black holes. Although the direct lensing effects are too small to be observed, the time delay between images produces interference fringes in the energy spectrum at wavelengths which will be accessible to GLAST in gamma ray bursts. This phenomenon is dubbed "attolensing." Assuming such primordial black holes comprise some fraction of the dark matter, we calculate the probability of observing attolensing of a GRB. The most significant contributions to the probability come from black holes outside of the solar system but within the Galaxy; the attolensing probability is on the same order as that of microlensing. We also simulate GLAST observations of attolensed GRBs to demonstrate with what confidence GLAST would be able to detect such an event.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. The Large Millimeter Telescope in the GLAST era

    SciTech Connect

    Carraminana, Alberto

    2007-07-12

    The Large Millimeter Telescope (LMT) was inaugurated on November 22, 2006. LMT will soon start commissioning and is expected to enter full science operations by 2008. With a 50m aperture, LMT will be the largest millimeter telescope and can become a powerful multiwavelength partner for GLAST. LMT will probe star formation at very high redshifts and can be used jointly with GLAST to uncover relativistic jet engines of flaring AGNs and GRBs. It will map with high resolution the distribution of molecular gas in nearby galaxies and in extended molecular clouds, providing an important input for gamma-ray emission models. These possibilities are a sample of how the Large Millimeter Telescope, working in a coordinated manner with GLAST, can become a powerful tool for high energy astrophysics.

  6. GeV Gamma-Ray Astronomy with GLAST

    SciTech Connect

    Kamae, T

    2004-05-11

    GLAST is NASA's next major mission to observe the gamma ray sky with unprecedented sensitivity in the energy range between 20 MeV and 300 GeV. The collaboration consisting of institutions in the US, France, Italy, Sweden and Japan is now building the engineering model to demonstrate validity of the flight model design. They will proceed to the flight model construction in the fall of 2002 which will be launched in March 2006. The instrument and science of GLAST Large Area Telescope will be described briefly here.

  7. The GLAST burst monitor instrument response simulation system

    NASA Astrophysics Data System (ADS)

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

    2005-07-01

    The GLAST Burst Monitor (GBM) is designed to provide wide field of view observations of gamma-ray bursts from 10keV to 25MeV. The GBM is composed of twelve NaI and two BGO detectors that are widely dispersed about the GLAST spacecraft. Reconstructing burst locations and energy spectra from these separated detectors requires detailed knowledge of the response to direct and scattered burst radiation. A simulation software package based on the GEANT4 Monte Carlo toolset is being developed to fulfill this requirement. We will discuss the architecture of our simulation system and evaluate the scientific capabilities of the GBM.

  8. 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.

  9. 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.

  10. 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.

  11. The Use of HepRep in GLAST

    SciTech Connect

    Perl, Joseph

    2003-07-10

    HepRep is a generic, hierarchical format for description of graphics representables that can be augmented by physics information and relational properties. It was developed for high energy physics event display applications and is especially suited to client/server or component frameworks. The GLAST experiment, an international effort led by NASA for a gamma-ray telescope to launch in 2006, chose HepRep to provide a flexible, extensible and maintainable framework for their event display without tying their users to any one graphics application. To support HepRep in their GUADI infrastructure, GLAST developed a HepRep filler and builder architecture. The architecture hides the details of XML and CORBA in a set of base and helper classes allowing physics experts to focus on what data they want to represent. GLAST has two GAUDI services: HepRepSvc, which registers HepRep fillers in a global registry and allows the HepRep to be exported to XML, and CorbaSvc, which allows the HepRep to be published through a CORBA interface and which allows the client application to feed commands back to GAUDI (such as start next event, or run some GAUDI algorithm). GLAST's HepRep solution gives users a choice of client applications, WIRED (written in Java) or FRED (written in C++ and Ruby), and leaves them free to move to any future HepRep-compliant event display.

  12. 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.

  13. Fermi's Large Area Telescope (LAT)

    NASA Image and Video Library

    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...

  14. 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.

  15. CCD star trackers

    NASA Technical Reports Server (NTRS)

    Goss, W. C.

    1975-01-01

    The application of CCDs to star trackers and star mappers is considered. Advantages and disadvantages of silicon CCD star trackers are compared with those of image dissector star trackers. It is concluded that the CCD has adequate sensitivity for most single star tracking tasks and is distinctly superior in multiple star tracking or mapping applications. The signal and noise figures of several current CCD configurations are discussed. The basic structure of the required signal processing is described, and it is shown that resolution in excess of the number of CCD elements may be had by interpolation.

  16. 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.

  17. The Gamma-ray Large Area Space Telescope (GLAST)

    NASA Technical Reports Server (NTRS)

    Ritz, Steve

    2008-01-01

    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 >300 GeV, with supporting measurements for gamma-ray bursts from 8 keV to 30 MeV. The very large field of view will make it possible to observe 20% of the sky at any instant, and the entire sky on a timescale of a few hours. With its upcoming launch, 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. In addition to the science opportunities, this talk includes a description of the instruments, the opportunities for guest investigators, and the mission status.

  18. 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.

  19. 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.

  20. Searching for the first blazars with LMT and GLAST

    SciTech Connect

    Rodriguez-Linan, Gustavo M.; Carraminana, Alberto

    2007-07-12

    Massive star formation and black hole growth are prone to be linked in massive protogalaxies. This relation has been studied at low redshifts, pointing to active galactic nuclei growing within dust enshrouded high redshift galaxies, a prime target of the Large Millimeter Telescope. The coincidence of GLAST sources with highly-obscured high-redshift LMT/GTM galaxies can be a powerful tool for studying the formation of the first blazars.

  1. 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}.

  2. Television Tracker Range Equation

    NASA Astrophysics Data System (ADS)

    Huan-Wen, Zhu

    1987-05-01

    The paper gives an approximate television tracker range equation based on the concept of the radiology and signal-to-noise of television system, and describes the physical process and mathematical method of reckoning range equation. The range equation is useful to the desing and development of a system. This paper also discusses the demand and selection standard of the television tracker system to the imaging device and gives some possible approaches to increase the range.

  3. 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.

  4. Advanced Imaging Tracker

    DTIC Science & Technology

    1982-06-01

    document requires that it 1e returncd: ADVANCED IMACINGC TRACKER Dr . L. E. Schmutz Contractor: Adaptive Optics Associates, Inc. Contt-ict Number: F30602-80...Code Number: IE20 Period of Worl: Covered: jun 80 - D’:c 81 Principal Investigator: Dr . Larry Schmut~z Phone: 617 547-2786 Project Engineer: Captaia...yaJPODCVR~ ADVANCED IMAGING TRACKER 10Jun 80 - ’,’ Dec 81 𔄃 PiRFORMiNO7 01G. REPORT NUMBER 7 ATII~(. ONTPA OR GRANTY NUMDERf.) Dr . 1L. E. Schiiut

  5. Digital Standard Star Tracker.

    NASA Astrophysics Data System (ADS)

    McQuerry, J. P., Jr.

    The Digital Standard Star Tracker (DSST) is an electro-optical instrument which provides position data used for precise attitude determination. The new DSST design uses flight-proven optical and sensor components from the BASD/NASA Standard Star Tracker (SST) programs while incorporating digital electronics techniques to improve producibility and reliability. This design approach has resulted in a new instrument capable of ≤ 10 arc second calibrated accuracy with 50 percent of the electrical components and only 10 percent of the electrical assemblies used in the SST.

  6. Digital Standard Star Tracker

    NASA Astrophysics Data System (ADS)

    McQuerry, J. P., Jr.

    The Digital Standard Star Tracker (DSST) is an electro-optical instrument which provides position data used for precise attitude determination. The new DSST design uses flight-proven optical and sensor components from the BASD/NASA Standard Star Tracker (SST) programs while incorporating digital electronics techniques to improve producibility and reliability. This design approach has resulted in a new instrument capable of less than 10 arc second calibrated accuracy with 50 percent of the electrical components and only 10 percent of the electrical assemblies used in the SST.

  7. 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…

  8. Ebola Tracker app.

    PubMed

    Evans, Roger

    2015-01-27

    Developer Bryan Ratledge claims his Ebola Tracker app is the only up to date mapping application of the 2014 Ebola virus disease outbreak centred in West Africa. With this app, you track the Ebola outbreak just as you would track a hurricane, or the weather.

  9. 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…

  10. 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…

  11. 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…

  12. 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.

  13. Gleam: the GLAST Large Area Telescope Simulation Framework

    SciTech Connect

    Dubois, Richard

    2003-08-22

    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.

  14. 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

  15. 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.

  16. High efficiency plastic scintillator detector with wavelength-shifting fiber readout for the GLAST Large Area Telescope

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

    This paper describes the design and performance studies of the scintillator tile detectors for the anti-coincidence detector (ACD) of the Large Area Telescope (LAT) on the Gamma ray Large Area Space Telescope (GLAST), scheduled for launch in early 2008. The scintillator tile detectors utilize wavelength-shifting fibers and have dual-photomultiplier-tube readout. The design requires highly efficient and uniform detection of singly charged relativistic particles over the tile area and must meet all requirements for a launch, as well as operation in a space environment. We present here the design of three basic types of tiles used in the ACD, ranging in size from ˜450 to ˜2500 cm2, all ˜1 cm thick, with different shapes, and with photoelectron yield of ˜20 photoelectrons per minimum ionizing particle at normal tile incidence, uniform over the tile area. Some tiles require flexible clear fiber cables up to 1.5 m long to deliver scintillator light to remotely located photomultiplier tubes.

  17. 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.

  18. The Gamma-ray Large Area Space Telescope (GLAST)

    NASA Technical Reports Server (NTRS)

    Ritz, Steve

    2008-01-01

    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 more than 300 GeV, with supporting measurements for gamma-ray bursts from 8 keV to 30 MeV. The very large field of view will make it possible to observe 20% of the sky at any instant, and the entire sky on a timescale of a few hours. With its upcoming launch, 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 opportunities for guest investigators, and the mission status.

  19. Measurements of Gamma-Ray Bursts with Glast

    NASA Astrophysics Data System (ADS)

    Lichti, G. G.; Briggs, M.; Diehl, R.; Fishman, G.; Greiner, J.; Kippen, R. M.; Kouveliotou, C.; Meegan, C.; Paciesas, W.; Preece, R.; Schönfelder, V.; von Kienlin, A.

    One of the scientific goals of the main instrument of l GLAST is the study of gamma-ray bursts (GRBs) in the energy range from ˜20 MeV to ˜300 GeV. In order to extend the energy measurement towards lower energies, a secondary instrument, the l GLAST Burst Monitor (GBM), will measure GRBs from ˜10 keV to ˜25 MeV and will therefore allow the investigation of the relation between the keV and the MeV--GeV emission from GRBs over six energy decades. These unprecedented measurements will permit the exploration of the unknown aspects of the high-energy burst emission and the investigation of their connection with the well-studied low-energy emission. They will also provide new insights into the physics of GRBs in general. In addition, the excellent localization of GRBs by the Large-Area Telescope will stimulate follow-up observations at other wavelengths which may yield clues about the nature of the burst sources.

  20. The Gamma-ray Large Area Space Telescope (GLAST)

    NASA Technical Reports Server (NTRS)

    Ritz, Steve

    2008-01-01

    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 more than 300 GeV, with supporting measurements for gamma-ray bursts from 8 keV to 30 MeV. The very large field of view will make it possible to observe 20% of the sky at any instant, and the entire sky on a timescale of a few hours. With its upcoming launch, 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 opportunities for guest investigators, and the mission status.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Sharper Fermi LAT Images: Instrument Response Functions for an Improved Event Selection

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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.

  8. 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.

  9. Alterations in the NF2/LATS1/LATS2/YAP Pathway in Schwannomas.

    PubMed

    Oh, Ji-Eun; Ohta, Takashi; Satomi, Kaishi; Foll, Matthieu; Durand, Geoffroy; McKay, James; Le Calvez-Kelm, Florence; Mittelbronn, Michel; Brokinkel, Benjamin; Paulus, Werner; Ohgaki, Hiroko

    2015-10-01

    Schwannomas are benign nerve sheath tumors composed of well-differentiated Schwann cells. Other than frequent NF2 (neurofibromatosis type 2) mutations (50%-60%), their molecular pathogenesis is not fully understood. LATS1 and LATS2 are downstream molecules of NF2 and are negative regulators of the yes-associated protein (YAP) oncogene in the Hippo signaling pathway. We assessed mutations of the NF2, LATS1, and LATS2 genes, promoter methylation of LATS1 and LATS2, and expression of YAP and phosphorylated YAP in 82 cases of sporadic schwannomas. Targeted sequencing using the Ion Torrent Proton instrument revealed NF2 mutations in 45 cases (55%), LATS1 mutations in 2 cases (2%), and LATS2 mutations in 1 case (1%) of schwannoma. Methylation-specific polymerase chain reaction showed promoter methylation of LATS1 and LATS2 in 14 cases (17%) and 25 cases (30%), respectively. Overall, 62 cases (76%) had at least 1 alteration in the NF2, LATS1, and/or LATS2 genes. Immunohistochemistry revealed nuclear YAP expression in 18 of 42 cases of schwannoma (43%) and reduced cytoplasmic phosphorylated YAP expression in 15 of 49 cases of schwannoma (31%), all of which had at least 1 alteration in the NF2, LATS1, and/or LATS2 genes. These results suggest that an abnormal Hippo signaling pathway is involved in the pathogenesis of most sporadic schwannomas.

  10. The LHCb Silicon Tracker

    NASA Astrophysics Data System (ADS)

    Tobin, Mark

    2016-09-01

    The LHCb experiment is dedicated to the study of heavy flavour physics at the Large Hadron Collider (LHC). The primary goal of the experiment is to search for indirect evidence of new physics via measurements of CP violation and rare decays of beauty and charm hadrons. The LHCb detector has a large-area silicon micro-strip detector located upstream of a dipole magnet, and three tracking stations with silicon micro-strip detectors in the innermost region downstream of the magnet. These two sub-detectors form the LHCb Silicon Tracker (ST). This paper gives an overview of the performance and operation of the ST during LHC Run 1. Measurements of the observed radiation damage are shown and compared to the expectation from simulation.

  11. ATLAS strip tracker stavelets

    NASA Astrophysics Data System (ADS)

    Phillips, P. W.

    2012-02-01

    The engineering challenges related to the supply of electrical power to future large scale detector systems are well documented. Two options remain under active study in our community, namely serial powering and the use of DC-DC converters. Whilst clearly different in detail, both have the potential to increase the efficiency of the powering system. The ATLAS Upgrade Strip Tracker Community has constructed two demonstrator stavelets using the ABCN-25 ASIC, each comprising four silicon strip detector modules. The first stavelet is serially powered, using shunt transistors integrated into the ABCN-25 chip to maintain the required operating voltage given a constant supply current, and the second stavelet uses STV-10 DC-DC converters provided by the CERN group. Although the detailed test programme shall continue at CERN, results from stavelet tests made at RAL are presented here.

  12. 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.

  13. Star trackers for spacecraft applications

    NASA Astrophysics Data System (ADS)

    Cassidy, Lawrence W.; Abreu, Rene

    1990-09-01

    During the last 10 years the need for a new generation of star trackers emerged as the requirements for space platform attitude control became more stringent. The Advanced Star Tracker (ASTRA) combines the high sensitivity and resolution inherent in a modern CCD detector with the versatile processing capability of a 16-bit microprocessor to achieve a level of performance surpassing existing trackers. In this paper, star tracker error sources and the design and calibration techniques utilized in ASTRA to eliminate or minimize those errors are explored. An error tree presents high and low special frequency centroiding error sources and their influence on the tracker's design. Requirements for thermal control of the detector and for optical calibration are discussed along with an overview of the data processing function. Finally, hardware test results are presented that demonstrate a significant improvement in accuracy and sensitivity relative to existing tube-type trackers.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Jets, Blazars and the EBL in the GLAST-EXIST Era

    NASA Astrophysics Data System (ADS)

    Grindlay, Jonathan E.; EXIST Team

    2007-07-01

    The synergy of GLAST and the proposed EXIST mission as the Black Hole Finder Probe in the Beyond Einstein Program is remarkable. With its full-sky per orbit hard X-ray imaging (3-600 keV) and ``nuFnu'' sensitivity comparable to GLAST, EXIST could measure variability and spectra of Blazars in the hard X-ray synchrotron component simultaneous with GLAST (~10-100GeV) measures of the inverse Compton component, thereby uniquely constraining intrinsic source spectra and allowing measured high energy spectral breaks to measure the cosmic diffuse extra-galactic background light (EBL) by determining the intervening diffuse IR photon field required to yield the observed break from photon-photon absorption. Such studies also constrain the physics of jets (and parameters and indeed the validity of SSC models) and the origin of the >100 MeV gamma-ray diffuse background likely arising from Blazars and jet-dominated sources. An overview of the EXIST mission, which could fly in the GLAST ere, is given together with a synopsis of other key synergies of GLAST-EXIST science.

  19. 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

  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. Simultaneous observation of the gamma-ray binary LS I+61 303 with GLAST and Suzaku

    SciTech Connect

    Tanaka, Takuya; Fukazawa, Yasushi; Mizuno, Tsunefumi; Katagiri, Hideaki; Takahashi, Hiromitsu; Kawabata, Koji S.; Nagae, Osamu; Ohsugi, Takashi

    2007-07-12

    The gamma-ray binary LS I+61 303 is a bright gamma-ray source, and thus an attracting object for GLAST. We proposed to observe this object with the X-ray satellite Suzaku (AO-2), simultaneously with GLAST, radio wave, and optical spectro-polarimetry, in order to probe the geometrical state of the binary system emitting the gamma-ray radiation, as a function of the binary orbital phase for the first time. This is essential to understand the mechanism of jet production and gamma-ray emission. The idea is not only to measure the multi-band overall continuum shape, but also to make use of continuous monitoring capability of GLAST, wide X-ray band of Suzaku, and good accessibility of the Kanata optical/NIR telescope (Hiroshima University) with the sensitive optical spectro-polarimetry. Further collaboration with TeV gamma-ray telescopes is also hoped to constrain the jet constitution.

  2. Head tracker evaluation utilizing the dynamic tracker test fixture

    NASA Astrophysics Data System (ADS)

    La Moure Shattuck, Judson, III; Parisi, Vincent M., II; Smerdon, Arryn J.

    2007-04-01

    In military aviation, head tracker technologies have become increasingly important to track the pilot's head position and orientation, allowing the user to quickly interact with the operational environment. This technology allows the pilot to quickly acquire items of interest and see Fighter Data Link type information. Acquiring the target on a helmet-mounted tracker/display which can automatically slew a weapon's seeker is far more efficient than having to point at the target with the nose of the aircraft as previously required for the heads-up display (HUD) type of target acquisition. The United States Air Force (USAF) has used and evaluated a variety of helmet-mounted trackers for incorporation into their high performance aircrafts. The Dynamic Tracker Test Fixture (DTTF) was designed by the Helmet-Mounted Sensory Technology (HMST) laboratory to accurately measure rotation in one plane both static and dynamic conditions for the purpose of evaluating the accuracy of head trackers, including magnetic, inertial, and optical trackers. This paper describes the design, construction, capabilities, limitations, and performance of the DTTF.

  3. 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.

  4. 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.

  5. 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).

  6. MAD for visual tracker fusion

    NASA Astrophysics Data System (ADS)

    Becker, Stefan; Krah, Sebastian B.; Hübner, Wolfgang; Arens, Michael

    2016-10-01

    Existing tracking methods vary strongly in their approach and therefore have different strengths and weaknesses. For example, a single tracking algorithm may be good at handling variations in illumination, but does not cope well with deformation. Hence, their failures can occur on entirely different time intervals on the same sequence. One possible solution for overcoming limitations of a single tracker and for benefitting from individual strengths, is to run a set of tracking algorithms in parallel and fuse their outputs. But in general, tracking algorithms are not designed to receive feedback from a higher level fusion strategy or require a high degree of integration between individual levels. Towards this end, we introduce a fusion strategy serving the purpose of online single object tracking, for which no knowledge about individual tracker characteristics is needed. The key idea is to combine several independent and heterogeneous tracking approaches and to robustly identify an outlier subset based on the "Median Absolute Deviations" (MAD) measure. The MAD fusion strategy is very generic and only requires frame-based object bounding boxes as input. Thus, it can work with arbitrary tracking algorithms. Furthermore, the MAD fusion strategy can also be applied for combining several instances of the same tracker to form a more robust ensemble for tracking an object. The evaluation is done on public available datasets. With a set of heterogeneous, commonly used trackers we show that the proposed MAD fusion strategy improves the tracking results in comparison to a classical combination of parallel trackers and that the tracker ensemble helps to deal with the initialization uncertainty of a single tracker.

  7. 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.

  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. The Search for Dark Matter via Gamma Rays from Astronomical Sources Using EGRET and GLAST

    SciTech Connect

    Bloom, E.

    2004-04-22

    EGRET, aboard NASA's CGRO satellite, has made important contributions to establishing limits on WIMP dark matter in the galaxy. This paper will review these EGRET results. Based on past limits and theoretical estimates, future potential dark matter results from GLAST are projected.

  10. Optimization of magnetic field system for glass spherical tokamak GLAST-III

    NASA Astrophysics Data System (ADS)

    Ahmad, Zahoor; Ahmad, S.; Naveed, M. A.; Deeba, F.; Aqib Javeed, M.; Batool, S.; Hussain, S.; Vorobyov, G. M.

    2017-04-01

    GLAST-III (Glass Spherical Tokamak) is a spherical tokamak with aspect ratio A = 2. The mapping of its magnetic system is performed to optimize the GLAST-III tokamak for plasma initiation using a Hall probe. Magnetic field from toroidal coils shows 1/R dependence which is typical with spherical tokamaks. Toroidal field (TF) coils can produce 875 Gauss field, an essential requirement for electron cyclotron resonance assisted discharge. The central solenoid (CS) of GLAST-III is an air core solenoid and requires compensation coils to reduce unnecessary magnetic flux inside the vessel region. The vertical component of magnetic field from the CS in the vacuum vessel region is reduced to 1.15 Gauss kA-1 with the help of a differential loop. The CS of GLAST can produce flux change up to 68 mVs. Theoretical and experimental results are compared for the current waveform of TF coils using a combination of fast and slow capacitor banks. Also the magnetic field produced by poloidal field (PF) coils is compared with theoretically predicted values. It is found that calculated results are in good agreement with experimental measurement. Consequently magnetic field measurements are validated. A tokamak discharge with 2 kA plasma current and pulse length 1 ms is successfully produced using different sets of coils.

  11. 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.

  12. 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.

  13. Head Tracker Evaluation Utilizing the Dynamic Tracker Test Fixture

    DTIC Science & Technology

    2007-03-01

    secondary system that updates the inertial system--often referred to as a hybrid system. Optical head trackers ( OHT ) are immune to magnetic field...S, ABBREVIATION CCW – Counter Clockwise CW – Clockwise Deg – Degrees D HUD – Head-up Display Min – Minute Mrad – milliradian N OHT – Optical

  14. Arsenite exposure downregulates EAAT1/GLAST transporter expression in glial cells.

    PubMed

    Castro-Coronel, Yaneth; Del Razo, Luz María; Huerta, Miriam; Hernandez-Lopez, Angeles; Ortega, Arturo; López-Bayghen, Esther

    2011-08-01

    Chronic exposure to inorganic arsenic severely damages the central nervous system (CNS). Glutamate (GLU) is the major excitatory amino acid and is highly neurotoxic when levels in the synaptic cleft are not properly regulated by a family of Na⁺-dependent excitatory amino acid transporters. Within the cerebellum, the activity of the Bergmann glia Na⁺-dependent GLU/aspartate transporter (GLAST) excitatory amino acid transporter 1 (EAAT1/GLAST) accounts for more than 90% of GLU uptake. Because exposure to the metalloid arsenite results in CNS toxicity, we examined whether EAAT1/GLAST constitutes a molecular target. To this end, primary cultures of chick cerebellar Bergmann glial cells were exposed to sodium arsenite for 24 h, and EAAT1/GLAST activity was evaluated via ³H-D-aspartate uptake. A sharp decrease in GLU transport was observed, and kinetic studies revealed protein kinase A, protein kinase C, and p38 mitogen-activated protein kinase-dependent decreases in K(M) and V(max) concomitant with diminished chglast transcription. To gain insight into the molecular mechanisms involved in these phenomena, we investigated the generation of reactive oxidative species and the lipid peroxidative damage caused by arsenite exposure. None of these responses were found, although we did observe an increase in nuclear factor (erythroid-derived 2)-like 2 DNA-binding activity correlated with a rise in total glutathione levels. Our results clearly suggest that EAAT1/GLAST is a molecular target of arsenite and support the critical involvement of glial cells in brain function and dysfunction.

  15. Lab Tracker and Copper Calculator

    MedlinePlus

    ... that you share this log of your treatment history with your physicians so that important trends in your health status can be noted. Patient Lab Tracker - Excel Version This format is downloadable to the Microsoft Excel program on your computer. Included are instructions and sample pages to assist ...

  16. Four-cell solar tracker

    NASA Technical Reports Server (NTRS)

    Berdahl, C. M.

    1981-01-01

    Forty cm Sun tracker, consisting of optical telescope and four solar cells, stays pointed at Sun throughout day for maximum energy collection. Each solar cell generates voltage proportional to part of solar image it receives; voltages drive servomotors that keep image centered. Mirrored portion of cylinder extends acquisition angle of device by reflecting Sun image back onto solar cells.

  17. 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.

  18. 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. Copyright © 2015 Elsevier B.V. and ECNP. All rights reserved.

  19. The Expression of Glutamate Aspartate Transporter (GLAST) within the Human Cochlea and its Distribution in Various Patient Populations

    PubMed Central

    Ahmed, Sameer; Vorasubin, Nopawan; Lopez, Ivan A; Hosokawa, Seiji; Ishiyama, Gail; Ishiyama, Akira

    2013-01-01

    Glutamate plays an important role in the central nervous system as an excitatory neurotransmitter. However, its abundance can lead to excitotoxicity which necessitates the proper function of active glutamate transporters. The glutamate-aspartate transporter (GLAST) has been shown to exist and function within non-human cochlear specimens regulating the inner ear glutamate concentration. In this study, we examined micro-dissected human cochleas from formalin-fixed celloidin-embedded temporal bone specimens of three different types of patients (Meniere's disease, normal controls, and other otopathologic conditions) and examined the differential expression of GLAST in the spiral ligament of the basal, middle, and apical turns of the cochlea. Immunohistochemical staining was performed with polyclonal antibodies against GLAST and image analysis was carried out with the Image J analysis software. In contrast to other studies with non-human specimens, GLAST was expressed in the spiral ligament fibrocytes but was not detected in the satellite cells of the spiral ganglia or supporting cells of the organ of Corti in the human cochlea. Our data also showed that GLAST expression significantly differs in the basal and apical turns of the cochlea. Lastly, post-hoc analysis showed a difference in the GLAST immunoreactive area of patients with Meniere's disease when compared to that of patients with other otopathologic conditions—such as presbycusis or ototoxicity. These results may potentially lead to further understanding of different disease states that affect hearing. PMID:23850643

  20. Contribution of LATS1 and LATS2 promoter methylation in OSCC development.

    PubMed

    Ladiz, Mohammad Ayoub Rigi; Najafi, Maryam; Kordi-Tamandani, Dor Mohammad

    2017-03-01

    The aberrant DNA methylation of the tumor suppressor genes involved in DNA Damage Response (DDR) signaling and cell cycle regulation may lead to the tumorigenesis. Our purpose here is to analyze the promoter methylation and mRNA expression levels of LATS1 and LATS2 (LATS1/2) genes in OSCC. Promoter methylation status of LATS1/2 genes was evaluated in 70 OSCC paraffin-embedded tissues and 70 normal oral samples, using Methylation Specific PCR (MSP). LATS1/2 mRNA expression profiles were also investigated in 14 OSCC patients and 14 normal samples, using real-time PCR. In both candidate genes, promoter methylation assessment revealed significant relationship between cases and controls (OR = 2.24, 95 % CI = 1.40-3.54, P = 0.001; LATS1 and OR = 15.5, 95%CI = 3.64-64.76, P < 0.001; LATS2). As well as, the evaluation of mRNA expression levels showed decreased expression in OSCC tissues in compare to control tissues. (Mean ± SD 1.74 ± 0.14 in OSCC versus 2.10 ± 0.24 in controls, P < 0.001; LATS1 and Mean ± SD 1.36 ± 0.077 in OSCC versus 1.96 ± 0.096 in controls, P < 0.001; LATS2). To the best our knowledge, this is the first report regarding the down-regulation of LATS1/2 through promoter methylation in OSCC. It is suggested to explore the down-stream transcription factors of both genes for finding the molecular mechanism of this deregulation in OSCC.

  1. LHCb Upgrade: Scintillating Fibre Tracker

    NASA Astrophysics Data System (ADS)

    Tobin, Mark; LHCb Upgrade Scintillating Fibre Tracker Group

    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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. The Gamma-ray Large Area Space Telescope (GLAST): Status and Plans

    NASA Technical Reports Server (NTRS)

    Ritz, Steve

    2008-01-01

    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 >300 GeV, with supporting measurements for gamma-ray bursts from 8 keV to 30 MeV. The very large field of view makes it possible to observe 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, GLAST now opens 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. In addition to the science opportunities, this talk includes a description of the instruments and the mission status and plans.

  8. Prospects for detecting dark matter with GLAST in light of the WMAP haze.

    SciTech Connect

    Hooper, D.; Zaharijas, G.; Finkbeiner, D. P.; Dobler, G.; High Energy Physics; FNAL; Harvard-Smithsonian Center for Astrophysics

    2008-02-01

    Observations by the Wilkinson Microwave Anisotropy Probe (WMAP) experiment have identified an excess of microwave emission from the center of the Milky Way. It has previously been shown that this 'WMAP haze' could be synchrotron emission from relativistic electrons and positrons produced in the annihilations of dark matter particles. In particular, the intensity, spectrum, and angular distribution of the WMAP haze is consistent with an electroweak scale dark matter particle (such as a supersymmetric neutralino or Kaluza-Klein dark matter in models with universal extra dimensions) annihilating with a cross section on the order of sigma {nu} {approx} 3 x 10{sup -26} cm{sup 3}/s and distributed with a cusped halo profile. No further exotic astrophysical or annihilation boost factors are required. If dark matter annihilations are in fact responsible for the observed haze, then other annihilation products will also be produced, including gamma rays. In this article, we study the prospects for the GLAST satellite to detect gamma rays from dark matter annihilations in the Galactic Center region in this scenario. We find that by studying only the inner 0.1{sup o} around the Galactic Center, GLAST will be able to detect dark matter annihilating to heavy quarks, gauge bosons, or tau leptons over astrophysical backgrounds with 5sigma (3sigma) significance if they are lighter than approximately 320-500 GeV (500-750 GeV). If the angular window is broadened to study the dark matter halo profile's angular extension (while simultaneously reducing the astrophysical backgrounds), weakly interacting, massive particles (WIMPs) as heavy as several TeV can be identified by GLAST with high significance. Only if the dark matter particles annihilate mostly to electrons or muons will GLAST be unable to identify the gamma ray spectrum associated with the WMAP haze.

  9. Chapter 6: CPV Tracking and Trackers

    SciTech Connect

    Luque-Heredia, Ignacio; Magalhaes, Pedro; Muller, Matthew

    2016-04-15

    This chapter explains the functional requirements of a concentrator photovoltaic (CPV) sun tracker. It derives the design specifications of a CPV tracker. The chapter presents taxonomy of trackers describing the most common tracking architectures, based on the number of axes, their relative position, and the foundation and placing of tracking drives. It deals with the structural issues related to tracker design, mainly related to structural flexure and its impact on the system's acceptance angle. The chapter analyzes the auto-calibrated sun tracking control, by describing the state of the art and its development background. It explores the sun tracking accuracy measurement with a practical example. The chapter discusses tracker manufacturing and tracker field works. It reviews survey of different types of tracker designs obtained from different manufacturers. Finally, the chapter deals with IEC62817, the technical standard developed for CPV sun trackers.

  10. Detecting the Attenuation of Blazar Gamma-ray Emission by Extragalactic Background Light with GLAST

    NASA Technical Reports Server (NTRS)

    Chen, Andrew; Ritz, Steven

    1999-01-01

    Gamma rays with energy above 10 GeV interact with optical-UV photons resulting in pair production. Therefore, a large sample of high redshift sources of these gamma rays can be used to probe the extragalactic background starlight (EBL) by examining the redshift dependence of the attenuation of the flux above 10 GeV. GLAST, the next generation high-energy gamma-ray telescope, will for the first time have the unique capability to detect thousands of gamma-ray blazars up to redshifts of at least z = 4, with enough angular resolution to allow identification of a large fraction of their optical counterparts. By combining recent determinations of the gamma-ray blazar luminosity function, recent calculations of the high energy gamma-ray opacity due to EBL absorption, and the expected GLAST instrument performance to produce simulated samples of blazars that GLAST would detect, including their redshifts and fluxes, we demonstrate that these blazars have the potential to be a highly effective probe of the EBL.

  11. 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.

  12. Star Tracker/Mapper: System Design Parameters

    DTIC Science & Technology

    1974-09-01

    AD-A008 554 STAR TRACKER/MAPPER: SYSTEM’DESIGN PARAMETERS F. W. Schenkel Johns Hopkins University Prepared for: Naval Plant Representative Office...APLIJHU TG 1256 4. TITLE (andSubritle) 5. TYPE OF REPORT & PERIOD COVERED Star Tracker/Mapper: System Design Parameters 6. PERFORMING ORG. REPORT...identify by block number) Design parameters Star tracker/mapper Optical sensors Optical trackers Spectral characteristics 20. ABSTRACT (Continue on

  13. 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

  14. 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

  15. 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.

  16. Overlap-Based Cell Tracker

    PubMed Central

    Chalfoun, Joe; Cardone, Antonio; Dima, Alden A.; Allen, Daniel P.; Halter, Michael W.

    2010-01-01

    In order to facilitate the extraction of quantitative data from live cell image sets, automated image analysis methods are needed. This paper presents an introduction to the general principle of an overlap cell tracking software developed by the National Institute of Standards and Technology (NIST). This cell tracker has the ability to track cells across a set of time lapse images acquired at high rates based on the amount of overlap between cellular regions in consecutive frames. It is designed to be highly flexible, requires little user parameterization, and has a fast execution time. PMID:27134800

  17. 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.

  18. D0 silicon microstrip tracker

    SciTech Connect

    Burdin, Sergey

    2005-11-01

    The D0 Run II silicon microstrip tracker (SMT) has 3 square meters of Si area. There are 792,576 channels read out by 6192 SVXIIe chips on 912 read out modules. The SMT provides track and vertex reconstruction capabilities over the full pseudorapidity coverage of the D0 detector. The full detector has been running successfully since April 2002. This presentation covers the experience in commissioning and operating, the recent electronics upgrade which improved stability of the SMT and estimates of the radiation damage.

  19. The CDF Central Outer Tracker

    SciTech Connect

    Pitts, K.T.; CDF Collaboration

    1997-01-01

    We describe the CDF Central Outer Tracker (COT), an open-cell drift chamber currently being constructed for the CDF detector to run at the upgraded Fermilab Tevatron collider. This detector will provide central tracking with excellent momentum resolution in the high- density environment of a hadron collider. It will be able to resolve 132 ns beam crossings and provide tracking trigger information to the Level 1 trigger. The design is based upon the existing and successful CDF Central Tracking Chamber. The preliminary mechanical and electrical designs are presented. 5 refs., 5 figs., 1 tab.

  20. 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

  1. 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.

  2. 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.

  3. The LAT story: a tale of cooperativity, coordination, and choreography.

    PubMed

    Balagopalan, Lakshmi; Coussens, Nathan P; Sherman, Eilon; Samelson, Lawrence E; Sommers, Connie L

    2010-08-01

    The adapter molecule LAT is a nucleating site for multiprotein signaling complexes that are vital for the function and differentiation of T cells. Extensive investigation of LAT in multiple experimental systems has led to an integrated understanding of the formation, composition, regulation, dynamic movement, and function of LAT-nucleated signaling complexes. This review discusses interactions of signaling molecules that bind directly or indirectly to LAT and the role of cooperativity in stabilizing LAT-nucleated signaling complexes. In addition, it focuses on how imaging studies visualize signaling assemblies as signaling clusters and demonstrate their dynamic nature and cellular fate. Finally, this review explores the function of LAT based on the interpretation of mouse models using various LAT mutants.

  4. Association of 4F2hc with light chains LAT1, LAT2 or y+LAT2 requires different domains.

    PubMed

    Bröer, A; Friedrich, B; Wagner, C A; Fillon, S; Ganapathy, V; Lang, F; Bröer, S

    2001-05-01

    Heterodimeric amino acid transporters are comprised of a type-II membrane protein named the heavy chain (4F2hc or rBAT) that may associate with a number of different polytopic membrane proteins, called light chains. It is thought that the heavy chain is mainly involved in the trafficking of the complex to the plasma membrane, whereas the transport process itself is catalysed by the light chain. The 4F2 heavy chain (4F2hc) associates with at least six different light chains to induce distinct amino acid-transport activites. To test if the light chains are specifically recognized and to identify domains involved in the recognition of light chains, C-terminally truncated mutants of 4F2hc were constructed and co-expressed with the light chains LAT1, LAT2 and y(+)LAT2. The truncated isoform T1, comprised of only 133 amino acids that form the cytosolic N-terminus and the transmembrane helix, displayed only a slight reduction in its ability to promote LAT1 expression at the membrane surface compared with the 529 amino acid wild-type 4F2hc protein. Co-expression of increasingly larger 4F2hc mutants caused a delayed translocation of LAT1. In contrast to the weak effects of 4F2hc truncations on LAT1 expression, surface expression of LAT2 and y(+)LAT2 was almost completely lost with all truncated heavy chains. Co-expression of LAT1 together with the other light chains did not result in displacement of LAT2 and y(+)LAT2. The results suggest that extracellular domains of the heavy chain are responsible mainly for recognition of light chains other than LAT1 and that the extracellular domain ensures proper translocation to the plasma membrane.

  5. Association of 4F2hc with light chains LAT1, LAT2 or y+LAT2 requires different domains.

    PubMed Central

    Bröer, A; Friedrich, B; Wagner, C A; Fillon, S; Ganapathy, V; Lang, F; Bröer, S

    2001-01-01

    Heterodimeric amino acid transporters are comprised of a type-II membrane protein named the heavy chain (4F2hc or rBAT) that may associate with a number of different polytopic membrane proteins, called light chains. It is thought that the heavy chain is mainly involved in the trafficking of the complex to the plasma membrane, whereas the transport process itself is catalysed by the light chain. The 4F2 heavy chain (4F2hc) associates with at least six different light chains to induce distinct amino acid-transport activites. To test if the light chains are specifically recognized and to identify domains involved in the recognition of light chains, C-terminally truncated mutants of 4F2hc were constructed and co-expressed with the light chains LAT1, LAT2 and y(+)LAT2. The truncated isoform T1, comprised of only 133 amino acids that form the cytosolic N-terminus and the transmembrane helix, displayed only a slight reduction in its ability to promote LAT1 expression at the membrane surface compared with the 529 amino acid wild-type 4F2hc protein. Co-expression of increasingly larger 4F2hc mutants caused a delayed translocation of LAT1. In contrast to the weak effects of 4F2hc truncations on LAT1 expression, surface expression of LAT2 and y(+)LAT2 was almost completely lost with all truncated heavy chains. Co-expression of LAT1 together with the other light chains did not result in displacement of LAT2 and y(+)LAT2. The results suggest that extracellular domains of the heavy chain are responsible mainly for recognition of light chains other than LAT1 and that the extracellular domain ensures proper translocation to the plasma membrane. PMID:11311135

  6. 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.

  7. Surface metrology using laser trackers

    NASA Astrophysics Data System (ADS)

    Enriquez, Rogerio; Sampieri, Cesar E.

    2005-02-01

    During the process of manufacture or measuring large components, position and orientation are needed thus; a method based in surveying the surface can be used to describe them. This method requires an ensemble of measurements of fixed points whose coordinates are unknown. Afterwards resulting observations are manipulated to determinate objects position in order to apply surface metrology. In this work, a methodology to reduce uncertainties in surface measuring is presented. When measuring large surfaces, numerical methods can reduce uncertainties in the measures, and this can be done with instruments as such as the Laser Tracker (LT). Calculations use range and angles measures, in order to determinate the coordinates of tridimensional unknown positions from differents surveying points. The purpose of this work, is to solve problems of surface metrology with given tolerances; with advantages in resources and results, instead of making time sacrifices. Here, a hybrid methodology is developed, combining Laser Tracker with GPS theories and analysis. Such a measuring position system can be used in applications where the use of others systems are unpractical, mainly because this kind of measuring instruments are portables and capable to track and report results in real-time, it can be used in virtually anyplace. Simulations to measure panels for the Large Millimetric Telescope (LMT/GTM) in Mexico were done. A first benefit from using this method is that instrument is not isolated from its measuring environment. Instead, the system is thought as a whole with operator, measuring environment and targets. This solution provides an effective way, and a more precise measurement, because it does optimize the use of the instrument and uses additional information to strength the solution.

  8. 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.

  9. 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.

  10. Progress on the MICE Tracker Solenoid

    SciTech Connect

    Green, Michael A.; Virostek, Steve P.; Lau, W.; Yang, Stephanie Q.

    2006-06-10

    This report describes the 400 mm warm bore tracker solenoid for the Muon Ionization Cooling Experiment (MICE). The 2.923 m long tracker solenoid module includes the radiation shutter between the end absorber focus coil modules and the tracker as well as the 2.735 m long magnet cryostat vacuum vessel. The 2.554 m long tracker solenoid cold mass consists of two sections, a three-coil spectrometer magnet and a two-coil matching section that matches the uniform field 4 T spectrometer solenoid into the MICE cooling channel. The two tracker magnets are used to provide a uniform magnetic field for the fiber detectors that are used to measure the muon beam emittance at the two ends of the cooling channel. This paper describes the design for the tracker magnet coils and the 4.2 K cryogenic coolers that are used to cool the superconducting magnet. Interfaces between the magnet and the detectors are discussed.

  11. An evolutionarily conserved negative feedback mechanism in the Hippo pathway reflects functional difference between LATS1 and LATS2

    PubMed Central

    Park, Gun-Soo; Oh, Hyangyee; Kim, Minchul; Kim, Tackhoon; Johnson, Randy L.; Irvine, Kenneth D.; Lim, Dae-Sik

    2016-01-01

    The Hippo pathway represses YAP oncoprotein activity through phosphorylation by LATS kinases. Although variety of upstream components has been found to participate in the Hippo pathway, the existence and function of negative feedback has remained uncertain. We found that activated YAP, together with TEAD transcription factors, directly induces transcription of LATS2, but not LATS1, to form a negative feedback loop. We also observed increased mRNA levels of Hippo upstream components upon YAP activation. To reveal the physiological role of this negative feedback regulation, we deleted Lats2 or Lats1 in the liver-specific Sav1-knockout mouse model which develops a YAP-induced tumor. Additional deletion of Lats2 severely enhanced YAP-induced tumorigenic phenotypes in a liver specific Sav1 knock-out mouse model while additional deletion of Lats1 mildly affected the phenotype. Only Sav1 and Lats2 double knock-down cells formed larger colonies in soft agar assay, thereby recapitulating accelerated tumorigenesis seen in vivo. Importantly, this negative feedback is evolutionarily conserved, as Drosophila Yorkie (YAP ortholog) induces transcription of Warts (LATS2 ortholog) with Scalloped (TEAD ortholog). Collectively, we demonstrated the existence and function of an evolutionarily conserved negative feedback mechanism in the Hippo pathway, as well as the functional difference between LATS1 and LATS2 in regulation of YAP. PMID:27006470

  12. An evolutionarily conserved negative feedback mechanism in the Hippo pathway reflects functional difference between LATS1 and LATS2.

    PubMed

    Park, Gun-Soo; Oh, Hyangyee; Kim, Minchul; Kim, Tackhoon; Johnson, Randy L; Irvine, Kenneth D; Lim, Dae-Sik

    2016-04-26

    The Hippo pathway represses YAP oncoprotein activity through phosphorylation by LATS kinases. Although variety of upstream components has been found to participate in the Hippo pathway, the existence and function of negative feedback has remained uncertain. We found that activated YAP, together with TEAD transcription factors, directly induces transcription of LATS2, but not LATS1, to form a negative feedback loop. We also observed increased mRNA levels of Hippo upstream components upon YAP activation. To reveal the physiological role of this negative feedback regulation, we deleted Lats2 or Lats1 in the liver-specific Sav1-knockout mouse model which develops a YAP-induced tumor. Additional deletion of Lats2 severely enhanced YAP-induced tumorigenic phenotypes in a liver specific Sav1 knock-out mouse model while additional deletion of Lats1 mildly affected the phenotype. Only Sav1 and Lats2 double knock-down cells formed larger colonies in soft agar assay, thereby recapitulating accelerated tumorigenesis seen in vivo. Importantly, this negative feedback is evolutionarily conserved, as Drosophila Yorkie (YAP ortholog) induces transcription of Warts (LATS2 ortholog) with Scalloped (TEAD ortholog). Collectively, we demonstrated the existence and function of an evolutionarily conserved negative feedback mechanism in the Hippo pathway, as well as the functional difference between LATS1 and LATS2 in regulation of YAP.

  13. High-speed mirror-scanning tracker

    NASA Astrophysics Data System (ADS)

    Tong, HengWei

    1999-06-01

    This paper introduces a high speed single-mirror scanner developed by us as a versatile tracker. It can be connected with a high speed camera, a TV tracker (or color video recorder) /measurer/recorder. It can be guided by a computer, a joystick (automatic or manual) or TV tracker. In this paper, we also present the advantages of our scanner contrasted with the limitations of fixed camera system. In addition, several usable projects of mirror scanner are discussed.

  14. 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

  15. Three Advantages of the KANATA 1.5-m Telescope as a Powerful Partner for GLAST

    SciTech Connect

    Uemura, M.; Yamashita, T.; Kawabata, K.; Ohsugi, T.; Arai, A.; Nagae, O.; Chiyonobu, S.; Ueda, A.; Fukazawa, Y.; Mizuno, T.; Katagiri, H.; Takahashi, H.; Hayashi, T.; Okita, K.; Yoshida, M.; Yanagisawa, K.; Sato, S.; Kino, M.; Kitagawa, M.; Sadakane, K.

    2007-07-12

    KANATA is a 1.5-m optical--near infrared telescope of Hiroshima University, which has been developed for observations of astronomical transients and variables, such as {gamma}-ray bursts, blazars. X-ray transients, and cataclysmic variables. Here, we introduce three characteristics of KANATA with examples of observations, that is, i) high ability for prompt observations, ii) simultaneous optical and infrared observations, and iii) polarimetric observations. Collaborating with GLAST, we are planning to perform follow-up optical--infrared observations of {gamma}-ray sources with KANATA.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Pulsar Timing with the Fermi LAT

    DTIC Science & Technology

    2010-12-01

    Pulsar Timing with the Fermi LAT Paul S. Ray∗, Matthew Kerr†, Damien Parent∗∗ and the Fermi PSC‡ ∗Naval Research Laboratory, 4555 Overlook Ave., SW...Laboratory, Washington, DC 20375, USA ‡Fermi Pulsar Search Consortium Abstract. We present an overview of precise pulsar timing using data from the Large...unbinned photon data. In addition to determining the spindown behavior of the pulsars and detecting glitches and timing noise, such timing analyses al

  1. FERMI-LAT Observations of Galatic Transients

    NASA Technical Reports Server (NTRS)

    Hays, Elizabeth

    2010-01-01

    This slide presentation reviews the use of the Large Area Telescope on the Fermi Observatory observations of Galactic Transients. LAT all-sky monitoring is producing spectacular results for the GeV transient sky: (1) New blazars and unidentified transients (2) Probing the jet of the Cygnus X-3 microquasar (3) Discovery of gamma rays from V407 Cygni nova (4) Fast high-energy gamma-ray flares from the Crab Nebula.

  2. 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.

  3. Sun tracker for clear or cloudy weather

    NASA Technical Reports Server (NTRS)

    Scott, D. R.; White, P. R.

    1979-01-01

    Sun tracker orients solar collector so that they absorb maximum possible sunlight without being fooled by bright clouds, holes in cloud cover, or other atmospheric conditions. Tracker follows sun within 0.25 deg arc and is accurate within + or - 5 deg when sun is hidden.

  4. 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…

  5. 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.

  6. LatMix 2011 and 2012 Dispersion Analysis

    DTIC Science & Technology

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. LatMix 2011 and 2012 Dispersion Analysis Miles A...continue analysis and publication of results obtained during the “Scalable Lateral Mixing and Coherent Turbulence” (a.k.a., LatMix) DRI. The initial...work included the airborne lidar operations as well as a substantial part of the field operations and analysis . A primary objective of our LatMix

  7. Eye trackers in an oculary clinical setting

    NASA Astrophysics Data System (ADS)

    Shahimin, Mizhanim M.; Shahimin, Mukhzeer M.

    2013-12-01

    Infrared eye tracker has been demonstrated to provide a more objective and quantitative results of the cover test measurement in eye care practices. This paper reviews the application of eye trackers in oculary clinical setting. It highlights the different types of eye movement recording system (EMRS) available, the advantages and disadvantages of each and their use in a clinical setting. This paper also discusses the parameters that can be derived from the EMRS and the significance of the parameters in a clinical interpretation. Using an eye tracker would make available to the clinician a simple system for making quantitative measurements when performing the cover test in an eye examination.

  8. 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.

  9. 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.

  10. Power distribution studies for CMS forward 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.

  11. My Game Plan: Food and Activity Tracker

    MedlinePlus

    ... partner organizations. SAMPLE ENTRY: TIME 8:00 AM MONDAY FOOD AND DRINK TRACKER AMOUNT /NAME /DESCRIPTION FAT ... TOTALS FAT GRAMS CALORIES MINUTES OF ACTIVITY WEIGHT MONDAY TUESDAY WEDNESDAY THURSDAY FRIDAY SATURDAY SUNDAY WEEKLY TOTALS ...

  12. A Tracker Alignment Framework for Augmented Reality

    DTIC Science & Technology

    2003-01-01

    A Tracker Alignment Framework for Augmented Reality Yohan Baillot and Simon J. Julier ITT Advanced Engineering & Sciences 2560 Huntington Ave...with as few as three measurements. 1. Introduction Almost all Augmented Reality (AR) systems use a track- ing system to capture motion of objects in...DATES COVERED 00-00-2003 to 00-00-2003 4. TITLE AND SUBTITLE A Tracker Alignment Framework for Augmented Reality 5a. CONTRACT NUMBER 5b. GRANT

  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. 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.

  16. Fate mapping by piggyBac transposase reveals that neocortical GLAST+ progenitors generate more astrocytes than Nestin+ progenitors in rat neocortex.

    PubMed

    Siddiqi, Faez; Chen, Fuyi; Aron, Abraham W; Fiondella, Christopher G; Patel, Komal; LoTurco, Joseph J

    2014-02-01

    Progenitors within the neocortical ventricular zone (VZ) first generate pyramidal neurons and then astrocytes. We applied novel piggyBac transposase lineage tracking methods to fate-map progenitor populations positive for Nestin or glutamate and aspartate transpoter (GLAST) promoter activities in the rat neocortex. GLAST+ and Nestin+ progenitors at embryonic day 13 (E13) produce lineages containing similar rations of neurons and astrocytes. By E15, the GLAST+ progenitor population diverges significantly to produce lineages with 5-10-fold more astrocytes relative to neurons than generated by the Nestin+ population. To determine when birth-dated progeny within GLAST+ and Nestin+ populations diverge, we used a Cre/loxP fate-mapping system in which plasmids are lost after a cell division. By E18, birth-dated progeny of GLAST+ progenitors give rise to 2-3-fold more neocortical astrocytes than do Nestin+ progenitors. Finally, we used a multicolor clonal labeling method to show that the GLAST+ population labeled at E15 generates astrocyte progenitors that produce larger, spatially restricted, clonal clusters than the Nestin+ population. This study provides in vivo evidence that by mid-corticogenesis (E15), VZ progenitor populations have significantly diversified in terms of their potential to generate astrocytes and neurons.

  17. 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.

  18. 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.

  19. 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.

  20. Fermi-LAT searches for γ-ray pulsars

    NASA Astrophysics Data System (ADS)

    Saz Parkinson, P. M.; Fermi LAT Collaboration

    2013-03-01

    The Large Area Telescope (LAT) on the Fermi satellite is the first γ-ray instrument to discover pulsars directly via their γ-ray emission. Roughly one third of the 117 γ-ray pulsars detected by the LAT in its first three years were discovered in blind searches of γ-ray data and most of these are undetectable with current radio telescopes. I review some of the key LAT results and highlight the specific challenges faced in γ-ray (compared to radio) searches, most of which stem from the long, sparse data sets and the broad, energy-dependent point-spread function (PSF) of the LAT. I discuss some ongoing LAT searches for γ-ray millisecond pulsars (MSPs) and γ-ray pulsars around the Galactic Center. Finally, I outline the prospects for future γ-ray pulsar discoveries as the LAT enters its extended mission phase, including advantages of a possible modification of the LAT observing profile.

  1. Phase-2 Upgrade of the CMS Tracker

    NASA Astrophysics Data System (ADS)

    Mersi, Stefano; CMS Collaboration

    2016-04-01

    An upgrade program is planned for the LHC which will smoothly bring the luminosity up to or above 5 ×1034 cm-2 s-1 sometimes after 2020, to possibly reach an integrated luminosity of 3000 fb-1 at the end of that decade. In this ultimate scenario, called Phase-2, when LHC will reach the High Luminosity phase (HL-LHC), CMS will need a completely new Tracker detector, in order to fully exploit the highly-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 and expected detector performance.

  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.

  3. 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.

  4. Results from the MSGC tracker at SMC

    NASA Astrophysics Data System (ADS)

    Ballintijn, M. K.; van den Berg, F. D.; van Dantzig, R.; Gracia, G.; de Groot, N.; Hartjes, F. G.; Horisberger, R.; Kaandorp, D.; Ketel, T. J.; Litmaath, M. F.; Niessink, J. J.; Ogawa, A.; Sichtermann, E. P.; Udo, F.; de Winter, A. R.

    1995-11-01

    A tracker consisting of 16 MSGCs has been installed in the high intensity muon beam of the SMC experiment[1] at CERN. Each MSGC has an active surface of 10 × 10 cm 2, covered by 496 anode strips. As a front-end amplifier the APC 64 is used. Results are presented about the efficiency, both at a high rate and at a low rate, and the position resolution. Using the data of the MSGC tracker the definition of the beam tracks in SMC significantly improved.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Sun Tracker Operates a Year Between Calibrations

    NASA Technical Reports Server (NTRS)

    Berdahl, C. M.

    1984-01-01

    Low-cost modification of Sun tracker automatically compensates equation of time and seasonal variations in declination of Sun. Output of Scotch Yoke drive mechanism adjusted through proper sizing of crank, yoke and other components and through choice of gear ratios to approximate seasonal northand south motion of Sun. Used for industrial solar-energy monitoring and in remote meteorological stations.

  13. Sun Tracker Operates a Year Between Calibrations

    NASA Technical Reports Server (NTRS)

    Berdahl, C. M.

    1984-01-01

    Low-cost modification of Sun tracker automatically compensates equation of time and seasonal variations in declination of Sun. Output of Scotch Yoke drive mechanism adjusted through proper sizing of crank, yoke and other components and through choice of gear ratios to approximate seasonal northand south motion of Sun. Used for industrial solar-energy monitoring and in remote meteorological stations.

  14. 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.

  15. Laser-assisted tympanostomy (LAT) in adult individuals

    NASA Astrophysics Data System (ADS)

    Prokopakis, E. P.; Lachanas, V. A.; Helidonis, Emmanuel S.; Velegrakis, G.

    2004-06-01

    Objectives: To assess outcome, in adult individuals undergone Laser Assisted Tympanostomy (LAT) without ventilation tube placement. Method: LAT was performed on a total of 95 ears (72 individuals). Indications included serous otitis media with effusion (44 ears/31 patients), eustachian tube dysfunction (32 ears/24 patients), acute otitis media (13 ears/11 patients), and endoscopic visualization of the middle ear (6 ears/6 patients). Results: Middle ear disease was resolved after the closure of tympanostomy in 48% of patients with serous otitis media with effusion. In 78% of patients with Eustachian tube dysfunction symptoms were diminished. All patients with acute otitis media had a satisfactory outcome. LAT was found quite effective in patients undergoing middle ear endoscopy. Conclusion: LAT without ventilation tubes provides a safe alternative surgical option in adult patients in certain cases. The selection criteria for this procedure are addressed in detail.

  16. LatMix 2011 and 2012 Dispersion Analysis

    DTIC Science & Technology

    2017-05-15

    was to complete the analysis and write -up of additional manuscripts relating to LatMix, and to further strengthen the results for multiple manuscripts...raw waveforms co llected during the LatMix 20 l I airborne lidar surveys, and completion of the analysis and write -up of major results stemming from...manuscripts published or submitted for publication. 2) Specific Objectives The primary objective of present effort was to complete the analysis and write

  17. Effect of C-terminal protein tags on pentitol and L-arabinose transport by Ambrosiozyma monospora Lat1 and Lat2 transporters in Saccharomyces cerevisiae.

    PubMed

    Londesborough, John; Richard, Peter; Valkonen, Mari; Viljanen, Kaarina

    2014-05-01

    Functional expression in heterologous hosts is often less successful for integral membrane proteins than for soluble proteins. Here, two Ambrosiozyma monospora transporters were successfully expressed in Saccharomyces cerevisiae as tagged proteins. Growth of A. monospora on l-arabinose instead of glucose caused transport activities of l-arabinose, l-arabitol, and ribitol, measured using l-[1-(3)H]arabinose, l-[(14)C]arabitol, and [(14)C]ribitol of demonstrated purity. A. monospora LAT1 and LAT2 genes were cloned earlier by using their ability to improve the growth of genetically engineered Saccharomyces cerevisiae on l-arabinose. However, the l-arabinose and pentitol transport activities of S. cerevisiae carrying LAT1 or LAT2 are only slightly greater than those of control strains. S. cerevisiae carrying the LAT1 or LAT2 gene fused in frame to the genes for green fluorescent protein (GFP) or red fluorescent protein (mCherry) or adenylate kinase (AK) exhibited large (>3-fold for LAT1; >20-fold for LAT2) increases in transport activities. Lat1-mCherry transported l-arabinose with high affinity (Km ≈ 0.03 mM) and l-arabitol and ribitol with very low affinity (Km ≥ 75 mM). The Lat2-GFP, Lat2-mCherry, and Lat2-AK fusion proteins could not transport l-arabinose but were high-affinity pentitol transporters (Kms ≈ 0.2 mM). The l-arabinose and pentitol transport activities of A. monospora could not be completely explained by any combination of the observed properties of tagged Lat1 and Lat2, suggesting either that tagging and expression in a foreign membrane alters the transport kinetics of Lat1 and/or Lat2 or that A. monospora contains at least one more l-arabinose transporter.

  18. Effect of C-Terminal Protein Tags on Pentitol and l-Arabinose Transport by Ambrosiozyma monospora Lat1 and Lat2 Transporters in Saccharomyces cerevisiae

    PubMed Central

    Richard, Peter; Valkonen, Mari; Viljanen, Kaarina

    2014-01-01

    Functional expression in heterologous hosts is often less successful for integral membrane proteins than for soluble proteins. Here, two Ambrosiozyma monospora transporters were successfully expressed in Saccharomyces cerevisiae as tagged proteins. Growth of A. monospora on l-arabinose instead of glucose caused transport activities of l-arabinose, l-arabitol, and ribitol, measured using l-[1-3H]arabinose, l-[14C]arabitol, and [14C]ribitol of demonstrated purity. A. monospora LAT1 and LAT2 genes were cloned earlier by using their ability to improve the growth of genetically engineered Saccharomyces cerevisiae on l-arabinose. However, the l-arabinose and pentitol transport activities of S. cerevisiae carrying LAT1 or LAT2 are only slightly greater than those of control strains. S. cerevisiae carrying the LAT1 or LAT2 gene fused in frame to the genes for green fluorescent protein (GFP) or red fluorescent protein (mCherry) or adenylate kinase (AK) exhibited large (>3-fold for LAT1; >20-fold for LAT2) increases in transport activities. Lat1-mCherry transported l-arabinose with high affinity (Km ≈ 0.03 mM) and l-arabitol and ribitol with very low affinity (Km ≥ 75 mM). The Lat2-GFP, Lat2-mCherry, and Lat2-AK fusion proteins could not transport l-arabinose but were high-affinity pentitol transporters (Kms ≈ 0.2 mM). The l-arabinose and pentitol transport activities of A. monospora could not be completely explained by any combination of the observed properties of tagged Lat1 and Lat2, suggesting either that tagging and expression in a foreign membrane alters the transport kinetics of Lat1 and/or Lat2 or that A. monospora contains at least one more l-arabinose transporter. PMID:24561586

  19. 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.

  20. 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.

  1. Electrical and optical measurements in the early hydrogen discharge of GLAST-III

    NASA Astrophysics Data System (ADS)

    Hussain, S.; Qayyum, A.; Ahmad, Z.; Ahmad, S.; Khan, R.; Naveed, M. A.; Ali, R.; Deeba, F.; Vorobyov, G. M.; GLAST Team

    2017-08-01

    This work presents the first electrical and optical measurements of the initial phase of hydrogen discharge in the upgraded spherical tokamak GLAST-III, initiated with electron cyclotron heating (ECH). Diagnostic measurements provide insights into expected and unexpected physics issues related to the initial phase of discharge. A triple Langmuir probe (TLP) has been developed to measure time series of the floating potential, plasma electron temperature and number density over the entire discharge, allowing monitoring of the two phases of the discharge: the ECH pre-ionization phase following by the plasma current formation phase. A TLP has the ability to give time-resolved measurements of the floating potential (V float), electron temperature (T e) and ion saturation current ({I}{{sat}}\\propto {n}{{e}}\\surd k{T}{{e}}). The evolution of the ECH-assisted pre-ionization and subsequent plasma current phases in one shot are well envisioned by the probe. Intense fluctuations in the plasma current phase advocate for efficient equilibrium and feedback control systems. Moreover, the emergence of some strong impurity lines in the emission spectrum, even after only a few shots, suggests a crucial need for improvements in the base vacuum level. A noticeable change in the shape of the temporal profiles of the floating potential, electron temperature, ion saturation current (I sat) and light emission has been observed with changing hydrogen fill pressure and vertical magnetic field.

  2. 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.

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

    NASA Astrophysics Data System (ADS)

    Bergström, Lars; Hooper, Dan

    2006-03-01

    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 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.

  4. 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.

  5. The first Fermi LAT supernova remnant catalog

    DOE PAGES

    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.

  8. Involvement of LAT1 and LAT2 in the high- and low-affinity transport of L-leucine in human retinal pigment epithelial cells (ARPE-19 cells).

    PubMed

    Yamamoto, Atsushi; Akanuma, Shin-Ichi; Tachikawa, Masanori; Hosoya, Ken-Ichi

    2010-05-01

    System L, which is encoded by LAT1 and LAT2, is an amino acid transport system that transports neutral amino acids, including several essential amino acids in an Na+-independent manner. Due to its broad substrate selectivity, system L has been proposed to mediate the transport of amino-acid-related drugs across the blood-tissue barriers. We characterized L-leucine transport and its corresponding transporter in a human retinal pigment epithelial cell line (ARPE-19 cells) as an in vitro model of the outer blood-retinal barrier. [3H]L-leucine uptake by ARPE-19 cells took place in an Na+-, Cl(-)-independent and saturable manner with K(m) values of 8.71 and 220 microM. This process was more potently cis-inhibited by substrates of LAT1 than those of LAT2. [3H]L-leucine efflux from ARPE-19 cells was trans-stimulated by substrates of LAT1 and LAT2 through the obligatory exchange mechanism of system L. Although RT-PCR analysis demonstrated that LAT1 and LAT2 mRNA are expressed in ARPE-19 cells, the LAT1 mRNA concentration is 42-fold higher than that of LAT2. Moreover, immunoblot analysis demonstrated that LAT1 is expressed in ARPE-19 cells. In conclusion, although the transport function of LAT1 is greater than that of LAT2, LAT1 and LAT2 are involved in L-leucine transport in ARPE-19 cells.

  9. Equation of state of tracker fields

    SciTech Connect

    Chiba, Takeshi

    2010-01-15

    We derive the equation of state of tracker fields, which are typical examples of freezing quintessence (quintessence with the equation of state approaching toward -1), taking into account of the late-time departure from the tracker solution due to the nonzero density parameter of dark energy {Omega}{sub {phi}.} We calculate the equation of state as a function of {Omega}{sub {phi}}for constant {Gamma}=VV{sup ''}/(V{sup '}){sup 2} (during matter era) models. The derived equation of state contains a single parameter, w{sub (0)}, which parametrizes the equation of state during the matter-dominated epoch. We derive observational constraints on w{sub (0)} and find that observational data are consistent with the cosmological constant: -1.11

  10. The Alpha Magnetic Spectrometer Silicon Tracker

    NASA Astrophysics Data System (ADS)

    Burger, W. J.

    1999-10-01

    The Alpha Magnetic Spectrometer (AMS) is designed as a independent module for installation on the International Space Station Alpha (ISSA) in the year 2002 for an operational period of three years. The principal scientific objectives are the searches for antimatter and dark matter in cosmic rays. The AMS uses 5.5m2 of silicon microstrip sensors to reconstruct charged particle trajectories in the field of a permanent magnet. The detector design and construction covered a 3yr period which terminated with a test flight on the NASA space shuttle Discovery during June 2-12, 1988. In this contribution, we describe the shuttle version of the AMS silicon tracker, including preliminary results of the tracker performance during the flight.

  11. Determination of Laser Tracker Angle Encoder Errors

    NASA Astrophysics Data System (ADS)

    Nasr, Karim M.; Hughes, Ben; Forbes, Alistair; Lewis, Andrew

    2014-08-01

    Errors in the angle encoders of a laser tracker may potentially produce large errors in long range coordinate measurements. To determine the azimuth angle encoder errors and verify their values stored in the tracker's internal error map, several methodologies were evaluated, differing in complexity, measurement time and the need for specialised measuring equipment. These methodologies are: an artefact-based technique developed by NIST; a multi-target network technique developed by NPL; and the classical precision angular indexing table technique. It is shown that the three methodologies agree within their respective measurement uncertainties and that the NPL technique has the advantages of a short measurement time and no reliance on specialised measurement equipment or artefacts.

  12. Muon trackers for imaging a nuclear reactor

    NASA Astrophysics Data System (ADS)

    Kume, N.; Miyadera, H.; Morris, C. L.; Bacon, J.; Borozdin, K. N.; Durham, J. M.; Fuzita, K.; Guardincerri, E.; Izumi, M.; Nakayama, K.; Saltus, M.; Sugita, T.; Takakura, K.; Yoshioka, K.

    2016-09-01

    A detector system for assessing damage to the cores of the Fukushima Daiichi nuclear reactors by using cosmic-ray muon tomography was developed. The system consists of a pair of drift-tube tracking detectors of 7.2× 7.2-m2 area. Each muon tracker consists of 6 x-layer and 6 y-layer drift-tube detectors. Each tracker is capable of measuring muon tracks with 12 mrad angular resolutions, and is capable of operating under 50-μ Sv/h radiation environment by removing gamma induced background with a novel time-coincidence logic. An estimated resolution to observe nuclear fuel debris at Fukushima Daiichi is 0.3 m when the core is imaged from outside the reactor building.

  13. Stereoscopic Video Weld-Seam Tracker

    NASA Technical Reports Server (NTRS)

    Kennedy, Larry Z.

    1991-01-01

    Stereoscopic video camera and laser illuminator operates in conjunction with image-data-processing computer to locate weld seam and to map surface features in vicinity of seam. Intended to track seams to guide placement of welding torch in automatic welding system and to yield information on qualities of welds. More sensitive than prior optical seam trackers and suitable for use in production environment. Tracks nearly invisible gap between butted machined edges of two plates.

  14. 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

  15. Research and Development of Scintillation fiber Trackers

    SciTech Connect

    Kobayashi, A.; ITO, H.; Kawai, H.; Kodama, S.; Kaneko, N.; Han, S.

    2015-07-01

    We are developing the scintillation fiber trackers. This detector is consist of 0.5 mm diameter scintillation fibers and PPDs. This detector has the doughnut shape with outer diameter of 50 cm and inner diameter of 10 cm and thickness of 2 mm. The position resolution is 70 μm. There are no ineffective area. And the cost is several million yen. (authors)

  16. 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.

  17. An optical tracker for the maritime environment

    NASA Astrophysics Data System (ADS)

    Bachoo, Asheer K.; le Roux, Francois; Nicolls, Fred

    2011-06-01

    Optical (visual) tracking is an important research area in computer vision with a wide range of useful and critical applications in defence and industry. The tracking of targets that pose a threat or potential threat to a country's assets and resources is a critical component in defence and security. In order to complement radar sensing applications, an optical tracker provides additional functions such as target detection, target identification and intent detection at the visual level. A tracker for the maritime environment is an optical system that performs the automatic tracking of an above water target. Ideally, a track of the target is required for as long as is possible. Some examples of targets include boats, yachts, ships, jet-skis and aircraft. A number of factors mitigate the performance of such a system - change in target appearance, target occlusions, platform vibration and scintillation in the atmosphere are some common examples. We present the implementation of a firstgeneration system that is robust to platform vibration, target appearance changes and short-term occlusions. The optical tracker is developed using a particle filter and an appearance model that is updated online. The system achieves real-time tracking through the use of non-specialized computer hardware. Promising results are presented for a number of real-world videos captured during field trials.

  18. A large Scintillating Fibre Tracker for LHCb

    NASA Astrophysics Data System (ADS)

    Greim, R.

    2017-02-01

    The LHCb experiment will be upgraded during LHC Long Shutdown 2 to be able to record data at a higher instantaneous luminosity. The readout rate is currently limited to 1 MHz by the Level 1 trigger. In order to achieve the target integrated luminosity of 50 fb-1 during LHC Run 3, all subdetectors have to be read out by a 40 MHz trigger-less readout system. Especially, the current tracking detectors downstream of the LHCb dipole magnet suffer from large detector dead times and a small granularity in the Outer Tracker, which consists of proportional straw tubes. Therefore, the Downstream Tracker will be replaced by a Scintillating Fibre Tracker with Silicon Photomultiplier readout. The total sensitive area of 340 m2 is made up of 2.5 m long fibre mats consisting of six staggered layers of 250 μm thin scintillating fibres. The scintillation light created by the charged particles traversing the fibre mats is transported to the fibre ends via total internal reflection and detected by state-of-the-art multi-channel SiPM arrays. This paper presents the detector concept, design, challenges, custom-made readout chips, as well as laboratory and beam test results.

  19. Posterior cerebellar Purkinje cells in an SCA5/SPARCA1 mouse model are especially vulnerable to the synergistic effect of loss of β-III spectrin and GLAST.

    PubMed

    Perkins, Emma M; Suminaite, Daumante; Clarkson, Yvonne L; Lee, Sin Kwan; Lyndon, Alastair R; Rothstein, Jeffrey D; Wyllie, David J A; Tanaka, Kohichi; Jackson, Mandy

    2016-08-15

    Clinical phenotypes of spinocerebellar ataxia type-5 (SCA5) and spectrin-associated autosomal recessive cerebellar ataxia type-1 (SPARCA1) are mirrored in mice lacking β-III spectrin (β-III(-/-)). One function of β-III spectrin is the stabilization of the Purkinje cell-specific glutamate transporter EAAT4 at the plasma membrane. In β-III(-/-) mice EAAT4 levels are reduced from an early age. In contrast levels of the predominant cerebellar glutamate transporter GLAST, expressed in Bergmann glia, only fall progressively from 3 months onwards. Here we elucidated the roles of these two glutamate transporters in cerebellar pathogenesis mediated through loss of β-III spectrin function by studying EAAT4 and GLAST knockout mice as well as crosses of both with β-III(-/-) mice. Our data demonstrate that EAAT4 loss, but not abnormal AMPA receptor composition, in young β-III(-/-) mice underlies early Purkinje cell hyper-excitability and that subsequent loss of GLAST, superimposed on the earlier deficiency of EAAT4, is responsible for Purkinje cell loss and progression of motor deficits. Yet the loss of GLAST appears to be independent of EAAT4 loss, highlighting that other aspects of Purkinje cell dysfunction underpin the pathogenic loss of GLAST. Finally, our results demonstrate that Purkinje cells in the posterior cerebellum of β-III(-/-) mice are most susceptible to the combined loss of EAAT4 and GLAST, with degeneration of proximal dendrites, the site of climbing fibre innervation, most pronounced. This highlights the necessity for efficient glutamate clearance from these regions and identifies dysregulation of glutamatergic neurotransmission particularly within the posterior cerebellum as a key mechanism in SCA5 and SPARCA1 pathogenesis.

  20. Fermi -Lat Observations Of The Geminga Pulsar

    DOE PAGES

    Abdo, A. A.

    2010-08-09

    We report on the Fermi-LAT observations of the Geminga pulsar, the second brightest non-variable GeV source in the γ-ray sky and the first example of a radio-quiet γ-ray pulsar. The observations cover one year, from the launch of the Fermi satellite through 2009 June 15. A data sample of over 60,000 photons enabled us to build a timing solution based solely on γ-rays. Timing analysis shows two prominent peaks, separated by Δphgr = 0.497 ± 0.004 in phase, which narrow with increasing energy. Pulsed γ-rays are observed beyond 18 GeV, precluding emission below 2.7 stellar radii because of magnetic absorption.more » The phase-averaged spectrum was fitted with a power law with exponential cutoff of spectral index Γ = (1.30 ± 0.01 ± 0.04), cutoff energy E 0 = (2.46 ± 0.04 ± 0.17) GeV, and an integral photon flux above 0.1 GeV of (4.14 ± 0.02 ± 0.32) × 10–6 cm–2 s–1. The first uncertainties are statistical and the second ones are systematic. The phase-resolved spectroscopy shows a clear evolution of the spectral parameters, with the spectral index reaching a minimum value just before the leading peak and the cutoff energy having maxima around the peaks. The phase-resolved spectroscopy reveals that pulsar emission is present at all rotational phases. The spectral shape, broad pulse profile, and maximum photon energy favor the outer magnetospheric emission scenarios.« less

  1. 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.

  2. 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

  3. Blazar Duty-Cycle at Gamma-Ray Frequecies: Constraints From Extragalactic Background Radiation And Prospects for AGILE And GLAST

    SciTech Connect

    Pittori, Carlotta; Cavazzuti, Elisabetta; Colafrancesco, Sergio; Giommi, Paolo

    2011-11-29

    We take into account the constraints from the observed extragalactic {gamma}-ray background to estimate the maximum duty cycle allowed for a selected sample of WMAP Blazars, in order to be detectable by AGILE and GLAST {gamma}-ray experiments. For the nominal sensitivity values of both instruments, we identify a subset of sources which can in principle be detectable also in a steady state without over-predicting the extragalactic background. This work is based on the results of a recently derived Blazar radio LogN-LogS obtained by combining several multi-frequency surveys.

  4. 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.; hide

    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.

  5. Fermi-LAT Observations of the LIGO Event GW150914

    NASA Technical Reports Server (NTRS)

    Ackermann, M.; Ajello, M.; Albert, A.; Anderson, B.; Arimoto, M.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; hide

    2016-01-01

    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 approx. 70 minutes of the trigger and thus enabled a comprehensive search for a gamma-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.

  6. 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.

  7. The first Fermi-LAT Gamma-Ray burst catalog

    DOE PAGES

    Ackermann, M.; Ajello, M.; Asano, K.; ...

    2013-10-23

    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 andmore » processed each of them using the same analysis sequence. Details of the methodology followed by the LAT collaboration for the GRB analysis are provided. Here, 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.« less

  8. Fermi-LAT Observations of the LIGO Event GW150914

    DOE PAGES

    Ackermann, M.; Ajello, M.; Albert, A.; ...

    2016-05-12

    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 study, 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-massmore » 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. Finally, 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.« less

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Dynamic exit pupil trackers for autostereoscopic displays.

    PubMed

    Akşit, Kaan; Baghsiahi, Hadi; Surman, Phil; Ölçer, Selim; Willman, Eero; Selviah, David R; Day, Sally; Urey, Hakan

    2013-06-17

    This paper describes the first demonstrations of two dynamic exit pupil (DEP) tracker techniques for autostereoscopic displays. The first DEP tracker forms an exit pupil pair for a single viewer in a defined space with low intraocular crosstalk using a pair of moving shutter glasses located within the optical system. A display prototype using the first DEP tracker is constructed from a pair of laser projectors, pupil-forming optics, moving shutter glasses at an intermediate pupil plane, an image relay lens, and a Gabor superlens based viewing screen. The left and right eye images are presented time-sequentially to a single viewer and seen as a 3D image without wearing glasses and allows the viewer to move within a region of 40 cm × 20 cm in the lateral plane, and 30 cm along the axial axis. The second DEP optics can move the exit pupil location dynamically in a much larger 3D space by using a custom spatial light modulator (SLM) forming an array of shutters. Simultaneous control of multiple exit pupils in both lateral and axial axes is demonstrated for the first time and provides a viewing volume with an axial extent of 0.6-3 m from the screen and within a lateral viewing angle of ± 20° for multiple viewers. This system has acceptable crosstalk (< 5%) between the stereo image pairs. In this novel version of the display the optical system is used as an advanced dynamic backlight for a liquid crystal display (LCD). This has advantages in terms of overall display size as there is no requirement for an intermediate image, and in image quality. This system has acceptable crosstalk (< 5%) between the stereo image pairs.

  15. Roadside Tracker Portal-less Portal Monitor

    SciTech Connect

    Ziock, Klaus-Peter; Cheriyadat, Anil M.; Bradley, Eric Craig; Cunningham, Mark F.; Fabris, Lorenzo; Goddard, Jr, James Samuel; Hornback, Donald Eric; Karnowski, Thomas Paul; Kerekes, Ryan A.; Newby, Jason

    2013-07-01

    This report documents the full development cycle of the Roadside Tracker (RST) Portal-less Portal monitor (Fig. 1) funded by DHS DNDO. The project started with development of a proof-of-feasibility proto-type, proceeded through design and construction of a proof-of-concept (POC) prototype, a test-and-evaluation phase, participation in a Limited Use Exercise that included the Standoff Radiation Detections Systems developed under an Advanced Technology Demonstration and concluded with participation in a Characterization Study conducted by DNDO.

  16. 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

  17. Activated PLC-γ1 is catalytically induced at LAT but activated PLC-γ1 is localized at both LAT- and TCR-containing complexes.

    PubMed

    Cruz-Orcutt, Noemi; Vacaflores, Aldo; Connolly, Sean F; Bunnell, Stephen C; Houtman, Jon C D

    2014-04-01

    Phospholipase C-γ1 (PLC-γ1) is a key regulator of T cell receptor (TCR)-induced signaling. Activation of the TCR enhances PLC-γ1 enzymatic function, resulting in calcium influx and the activation of PKC family members and RasGRP. The current model is that phosphorylation of LAT tyrosine 132 facilitates the recruitment of PLC-γ1, leading to its activation and function at the LAT complex. In this study, we examined the phosphorylation kinetics of LAT and PLC-γ1 and the cellular localization of activated PLC-γ1. We observed that commencement of the phosphorylation of LAT tyrosine 132 and PLC-γ1 tyrosine 783 occurred simultaneously, supporting the current model. However, once begun, PLC-γ1 activation occurred more rapidly than LAT tyrosine 132. The association of LAT and PLC-γ1 was more transient than the interaction of LAT and Grb2 and a pool of activated PLC-γ1 translocated away from LAT to cellular structures containing the TCR. These studies demonstrate that LAT and PLC-γ1 form transient interactions that catalyze the activation of PLC-γ1, but that activated PLC-γ1 resides in both LAT and TCR clusters. Together, this work highlights that our current model is incomplete and the activation and function of PLC-γ1 in T cells is highly complex.

  18. Activated PLC-γ1 is Catalytically Induced at LAT but Activated PLC-γ1 is Localized at both LAT- and TCR-Containing Complexes

    PubMed Central

    Cruz-Orcutt, Noemi; Vacaflores, Aldo; Connolly, Sean F.; Bunnell, Stephen C.; Houtman, Jon C.D.

    2014-01-01

    Phospholipase C-γ1 (PLC-γ1) is a key regulator of T cell receptor (TCR)-induced signaling. Activation of the TCR enhances PLC-γ1 enzymatic function, resulting in calcium influx and the activation of PKC family members and RasGRP. The current model is that phosphorylation of LAT tyrosine 132 facilitates the recruitment of PLC-γ1, leading to its activation and function at the LAT complex. In this study, we examined the phosphorylation kinetics of LAT and PLC-γ1 and the cellular localization of activated PLC-γ1. We observed that commencement of the phosphorylation of LAT tyrosine 132 and PLC-γ1 tyrosine 783 occurred simultaneously, supporting the current model. However, once begun, PLC-γ1 activation occurred more rapidly than LAT tyrosine 132. The association of LAT and PLC-γ1 was more transient than the interaction of LAT and Grb2 and a pool of activated PLC-γ1 translocated away from LAT to cellular structures containing the TCR. These studies demonstrate that LAT and PLC-γ1 form transient interactions that catalyze the activation of PLC-γ1, but that activated PLC-γ1 resides in both LAT and TCR clusters. Together, this work highlights that our current model is incomplete and the activation and function of PLC-γ1 in T cells is highly complex. PMID:24412752

  19. CellTracker (not only) for dummies.

    PubMed

    Piccinini, Filippo; Kiss, Alexa; Horvath, Peter

    2016-03-15

    Time-lapse experiments play a key role in studying the dynamic behavior of cells. Single-cell tracking is one of the fundamental tools for such analyses. The vast majority of the recently introduced cell tracking methods are limited to fluorescently labeled cells. An equally important limitation is that most software cannot be effectively used by biologists without reasonable expertise in image processing. Here we present CellTracker, a user-friendly open-source software tool for tracking cells imaged with various imaging modalities, including fluorescent, phase contrast and differential interference contrast (DIC) techniques. CellTracker is written in MATLAB (The MathWorks, Inc., USA). It works with Windows, Macintosh and UNIX-based systems. Source code and graphical user interface (GUI) are freely available at: http://celltracker.website/ horvath.peter@brc.mta.hu Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  20. 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.

  1. The NA62 GigaTracker

    NASA Astrophysics Data System (ADS)

    Aglieri Rinella, G.; Feito, D. Alvarez; Arcidiacono, R.; Biino, C.; Bonacini, S.; Ceccucci, A.; Chiozzi, S.; Gil, E. Cortina; Ramusino, A. Cotta; Degrange, J.; Fiorini, M.; Gamberini, E.; Gianoli, A.; Kaplon, J.; Kluge, A.; Mapelli, A.; Marchetto, F.; Minucci, E.; Morel, M.; Noël, J.; Noy, M.; Perktold, L.; Perrin-Terrin, M.; Petagna, P.; Petrucci, F.; Poltorak, K.; Romagnoli, G.; Ruggiero, G.; Velghe, B.; Wahl, H.

    2017-02-01

    The GigaTracker is a hybrid silicon pixel detector built for the NA62 experiment aiming at measuring the branching fraction of the ultra-rare kaon decay K+ →π+ ν ν bar at the CERN SPS. The detector has to track particles in a beam with a flux reaching 1.3 MHz/mm2 and provide single-hit timing with 200 ps RMS resolution for a total material budget of less than 0.5% X0 per station. The tracker comprises three 60.8 mm×27 mm stations installed in vacuum (∼10-6 mbar) and cooled with liquid C6F14 circulating through micro-channels etched inside a few hundred micron thick silicon plates. Each station is composed of a 200 μm thick silicon sensor read out by 2×5 custom 100 μm thick ASICs, called TDCPix. Each chip contains 40×45 asynchronous pixels, 300 μm×300 μm each and is instrumented with 100 ps bin time-to-digital converters. In order to cope with the high rate, the TDCPix is equipped with four 3.2 Gb/s serialisers sending out the data. We will describe the detector and the results from the 2014 and 2015 NA62 runs.

  2. Modeling of intensified high dynamic star tracker.

    PubMed

    Yan, Jinyun; Jiang, Jie; Zhang, Guangjun

    2017-01-23

    An intensified high dynamic star tracker (IHDST) is a photoelectric instrument and stably outputs three-axis attitude for a spacecraft at very high angular velocity. The IHDST uses an image intensifier to multiply the incident starlight. Thus, high sensitivity of the star detection is achieved under short exposure time such that extremely high dynamic performance is achieved. The IHDST differs from a traditional star tracker in terms of the imaging process. Therefore, we establish a quantum transfer model of IHDST based on stochastic process theory. By this model, the probability distribution of the output quantum number is obtained accurately. Then, we introduce two-dimensional Lorentz functions to describe the spatial spreading process of the IHDST. Considering the interaction of these two processes, a complete star imaging model of IHDST is provided. Using this model, the centroiding accuracy of the IHDST is analyzed in detail. Accordingly, a working parameter optimizing strategy is developed for high centroiding accuracy and improved dynamic performance. Finally, the laboratory tests and the night sky experiment support the conclusions.

  3. 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.

  4. LAT1 is the transport competent unit of the LAT1/CD98 heterodimeric amino acid transporter.

    PubMed

    Napolitano, Lara; Scalise, Mariafrancesca; Galluccio, Michele; Pochini, Lorena; Albanese, Leticia Maria; Indiveri, Cesare

    2015-10-01

    LAT1 (SLC7A5) and CD98 (SLC3A2) constitute a heterodimeric transmembrane protein complex that catalyzes amino acid transport. Whether one or both subunits are competent for transport is still unclear. The present work aims to solve this question using different experimental strategies. Firstly, LAT1 and CD98 were immuno-detected in protein extracts from SiHa cells. Under oxidizing conditions, i.e., without addition of SH (thiol) reducing agent DTE, both proteins were revealed as a 120kDa major band. Upon DTE treatment separated bands, corresponding to LAT1(35kDa) or CD98(80kDa), were detected. LAT1 function was evaluated in intact cells as BCH sensitive [(3)H]His transport inhibited by hydrophobic amino acids. Antiport of [(3)H]His was measured in proteoliposomes reconstituted with SiHa cell extract in presence of internal His. Transport was increased by DTE. Hydrophobic amino acids were best inhibitors in addition to hydrophilic Tyr, Gln, Asn and Lys. Cys, Tyr and Gln, included in the intraliposomal space, were transported in antiport with external [(3)H]His. Similar experiments were performed in proteoliposomes reconstituted with the recombinant purified hLAT1. Results overlapping those obtained with native protein were achieved. Lower transport of [(3)H]Leu and [(3)H]Gln with respect to [(3)H]His was detected. Kinetic asymmetry was found with external Km for His lower than internal one. No transport was detected in proteoliposomes reconstituted with recombinant hCD98. The experimental data demonstrate that LAT1 is the sole transport competent subunit of the heterodimer. This conclusion has important outcome for following studies on functional characterization and identification of specific inhibitors with potential application in human therapy.

  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. Mechatronic Prototype of Parabolic Solar Tracker.

    PubMed

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

    2016-06-15

    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.

  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. 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.

  9. 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

  10. The CHARA Array's Visible Band Fringe Tracker

    NASA Astrophysics Data System (ADS)

    Ogden, C. E.; ten Brummelaar, T.; Berger, D. H.

    2003-12-01

    The CHARA Array is a Y-shaped cluster of 1-meter telescopes used to make interferometric measurements of stars. The optical paths from each telescope to the beam combiner must be matched in order to detect interference fringes. Atmospheric turbulence introduces a varying piston error in each telescope's optical path, which must be removed to stabilize the fringe position. The CHARA array separates the fringe tracker from the science combiner to keep the instrument flexible. The science combiner operates in the K' filter, leaving the visible band, from 0.6 μm to 1 μm for the fringe tracker. After beam combination, the visible light passes into the spectrograph, which is composed of a prism and a fast readout CCD. When the optical path difference (OPD) of two telescopes is near zero, the spectrum is modulated by sinusoidal fringes, called "channel fringes." The spatial frequency of the channel fringes is proportional to the OPD, and can be used as the error signal for a fringe tracking servo. A brief overview of the fringe tracking servo is presented, and current technical challenges are discussed. First channel fringe data are included, as well as a discussion of what they imply about atmospheric turbulence on Mount Wilson. Construction of the CHARA Array was made possible by grants from the National Science Foundation, the W. M. Keck Foundation, and the David and Lucile Packard Foundation, and by the generous support of Georgia State University. This research was also funded in part by the Michelson Fellowship Program sponsored by the NASA Jet Propulsion Laboratory.

  11. 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.

  12. Theoretical Interpretation of Pass 8 Fermi -LAT e + + e - Data

    DOE PAGES

    Di Mauro, M.; Manconi, S.; Vittino, A.; ...

    2017-08-17

    The flux of positrons and electrons (e + + e -) has been measured by the Fermi Large Area Telescope (LAT) in the energy range between 7 GeV and 2 TeV. Here, we discuss a number of interpretations of Pass 8 Fermi-LAT e sup>+ + e - spectrum, combining electron and positron emission from supernova remnants (SNRs) and pulsar wind nebulae (PWNe), or produced by the collision of cosmic rays (CRs) with the interstellar medium. We also found that the Fermi-LAT spectrum is compatible with the sum of electrons from a smooth SNR population, positrons from cataloged PWNe, and amore » secondary component. If we include in our analysis constraints from the AMS-02 positron spectrum, we obtain a slightly worse fit to the e sup>+ + e - Fermi-LAT spectrum, depending on the propagation model. As an additional scenario, we replace the smooth SNR component within 0.7 kpc with the individual sources found in Green's catalog of Galactic SNRs. We find that separate consideration of far and near sources helps to reproduce the e sup>+ + e - Fermi-LAT spectrum. However, we show that the fit degrades when the radio constraints on the positron emission from Vela SNR (which is the main contributor at high energies) are taken into account. We find that a break in the power-law injection spectrum at about 100 GeV can also reproduce the measured e sup>+ + e - spectrum and, among the CR propagation models that we consider, no reasonable break of the power-law dependence of the diffusion coefficient can modify the electron flux enough to reproduce the observed shape.« less

  13. LATS1/WARTS phosphorylates MYPT1 to counteract PLK1 and regulate mammalian mitotic progression

    PubMed Central

    Chiyoda, Tatsuyuki; Sugiyama, Naoyuki; Shimizu, Takatsune; Naoe, Hideaki; Kobayashi, Yusuke; Ishizawa, Jo; Arima, Yoshimi; Tsuda, Hiroshi; Ito, Masaaki; Kaibuchi, Kozo; Aoki, Daisuke; Ishihama, Yasushi

    2012-01-01

    In the mitotic exit network of budding yeast, Dbf2 kinase phosphorylates and regulates Cdc14 phosphatase. In contrast, no phosphatase substrates of LATS1/WARTS kinase, the mammalian equivalent of Dbf2, has been reported. To address this discrepancy, we performed phosphoproteomic screening using LATS1 kinase. Screening identified MYPT1 (myosin phosphatase–targeting subunit 1) as a new substrate for LATS1. LATS1 directly and preferentially phosphorylated serine 445 (S445) of MYPT1. An MYPT1 mutant (S445A) failed to dephosphorylate Thr 210 of PLK1 (pololike kinase 1), thereby activating PLK1. This suggests that LATS1 promotes MYPT1 to antagonize PLK1 activity. Consistent with this, LATS1-depleted HeLa cells or fibroblasts from LATS1 knockout mice showed increased PLK1 activity. We also found deoxyribonucleic acid (DNA) damage–induced LATS1 activation caused PLK1 suppression via the phosphorylation of MYPT1 S445. Furthermore, LATS1 knockdown cells showed reduced G2 checkpoint arrest after DNA damage. These results indicate that LATS1 phosphorylates a phosphatase as does the yeast Dbf2 and demonstrate a novel role of LATS1 in controlling PLK1 at the G2 DNA damage checkpoint. PMID:22641346

  14. Optimization Method for Solution Model of Laser Tracker Multilateration Measurement

    NASA Astrophysics Data System (ADS)

    Chen, Hongfang; Tan, Zhi; Shi, Zhaoyao; Song, Huixu; Yan, Hao

    2016-08-01

    Multilateration measurement using laser trackers suffers from a cumbersome solution method for high-precision measurements. Errors are induced by the self-calibration routines of the laser tracker software. This paper describes an optimization solution model for laser tracker multilateration measurement, which effectively inhibits the negative effect of this self-calibration, and further, analyzes the accuracy of the singular value decomposition for the described solution model. Experimental verification for the solution model based on laser tracker and coordinate measuring machine (CMM) was performed. The experiment results show that the described optimization model for laser tracker multilateration measurement has good accuracy control, and has potentially broad application in the field of laser tracker spatial localization.

  15. Maximum energy yield approach for CPV tracker design

    NASA Astrophysics Data System (ADS)

    Aldaiturriaga, E.; González, O.; Castro, M.

    2012-10-01

    Foton HC Systems has developed a new CPV tracker model, specially focused on its tracking efficiency and the effect of the tracker control techniques on the final energy yield of the system. This paper presents the theoretical work carried out into determining the energy yield for a CPV system, and illustrates the steps involved in calculating and understanding how energy consumption for tracking is opposed to tracker pointing errors. Additionally, the expressions to compute the optimum parameters are presented and discussed.

  16. 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.

  17. LAT alleviates Th2/Treg imbalance in an OVA-induced allergic asthma mouse model through LAT-PLC-γ1 interaction.

    PubMed

    Chen, Xi; Li, Xiao-Ming; Gu, Wen; Wang, Di; Chen, Yi; Guo, Xue-Jun

    2017-03-01

    Low expression of linker for activation of T cells (LAT) is observed in asthma. LAT and its downstream regulator, phospholipase C-gamma 1 (PLC-γ1) play important roles in the T cell antigen receptor signaling pathway, and their interaction is associated with CD4(+) cell polarization. Here, we investigated whether LAT can alleviate the imbalance among CD4(+) cell subgroups and the possible mechanism. An ovalbumin-induced allergic asthma mouse model was established and LAT plasmid was delivered. The pathological changes in lung were evaluated by hematoxylin and eosin and periodic acid-Schiff staining. The typical cytokines released by T helper 2 (Th2) and regulatory T (Treg) cells were measured using enzyme-linked immunosorbent assay and the number of Th1, Th2, and Treg cells were determined using flow cytometry. Lung CD4(+) T cells were isolated by magnetic isolation. The mRNA expression of LAT and PLC-γ1 was determined by real-time PCR. Co-Immunoprecipitation was performed to confirm the interaction between LAT and PLC-γ1. The protein expression of LAT, PLC-γ1 and corresponding downstream signaling factors were determined by western blotting. The delivery of LAT DNA to the lung could suppress an overactive Th2 response by decreasing allergic response and Th2 cytokine secretion, and by increasing Treg cytokine secretion. The Th2/Treg imbalance in lung and decreased phosphorylated PLC-γ1 expression in lung CD4(+) T cells were rectified by LAT DNA delivery. Excessive activation of the Raf-MEK-ERK and PI3K-AKT-CREB pathways after asthma is attenuated by LAT. The site-specific delivery of LAT DNA to the lung could suppress an overactive Th2 response and rectify the Th2/Treg imbalance in asthmatic mouse model. LAT-PLC-γ1 interaction may contribute to LAT activity in vivo and LAT protects against asthma partly via Raf-MEK-ERK and PI3K-AKT-CREB pathways. The delivery of LAT DNA could offer a novel and safe strategy for asthma prevention. Copyright © 2016 Elsevier B

  18. Tissue-Specific Splicing of the Herpes Simplex Virus Type 1 Latency-Associated Transcript (LAT) Intron in LAT Transgenic Mice

    PubMed Central

    Gussow, Anne M.; Giordani, Nicole V.; Tran, Robert K.; Imai, Yumi; Kwiatkowski, Dacia L.; Rall, Glenn F.; Margolis, Todd P.; Bloom, David C.

    2006-01-01

    To study the regulation of herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) expression and processing in the absence of other cis and trans viral functions, a transgenic mouse containing the region encompassing the LAT promoter (LAP1) and the LAT 5′ exon through the 2.0-kb intron was created. LAT expression was detectable by reverse transcriptase PCR (RT-PCR) in a number of tissues, including the dorsal root ganglia (DRG), trigeminal ganglia (TG), brain, skin, liver, and kidney. However, when the accumulation of the 2.0-kb LAT intron was analyzed at the cellular level by in situ hybridization, little or no detectable accumulation was observed in the brain, spinal cord, kidney, or foot, although the 2.0-kb LAT intron was detected at high levels (over 90% of neurons) in the DRG and TG. Northern blot analysis detected the stable 2.0-kb LAT intron only in the sensory ganglia. When relative amounts of the spliced and unspliced LAT within the brain, liver, kidney, spinal cord, TG, and DRG were analyzed by real-time RT-PCR, splicing of the 2.0-kb LAT intron was significantly more efficient in the sensory ganglia than in other tissues. Finally, infection of both transgenic mice and nontransgenic littermates with HSV-1 revealed no differences in lytic replication, establishment of latency, or reactivation, suggesting that expression of the LAT transgene in trans has no significant effect on those functions. Taken together, these data indicate that the regulation of expression and processing of LAT RNA within the mouse is highly cell-type specific and occurs in the absence of other viral cis- and trans-acting factors. PMID:16973547

  19. The Utilization of the RCT Telescope for Studies of Blazar Continuum Emission during the GLAST Gamma-Ray Mission

    NASA Astrophysics Data System (ADS)

    Mattox, J. R.; Cominsky, L.; Spear, G.; Carinni, M.; Gelderman, R.; McGruder, C. H.; Guinan, E.; Howell, S.; Davis, D. R.; Everett, M.; Walter, D. K.

    2003-05-01

    The RCT Consortium successfully proposed to refurbish and automate the Kitt Peak 1.3-m telescope, and to operate it as the Robotically Controlled Telescope (RCT). Refurbishment is nearing completion, and observations have begun. The capabilities of the RCT for broad-band optical photometry will be described. A program for systematic optical monitoring of blazars with the RCT is planned. We anticipate that an important utilization of the RCT will be in conjunction with multi-wavelength studies of blazar continuum emission during the operation of NASA's Gamma-ray Large Area Space Telescope (GLAST) satellite, now scheduled for launch in 2006. Refurbishment of the RCT has been made possible by NASA grant NAG58762.

  20. Advanced electro-optical tracker/ranger

    NASA Astrophysics Data System (ADS)

    Bennett, R. A.; Defoe, D. N.

    1980-06-01

    The preliminary engineering design study of an Advanced Electro-Optical Tracker/Ranger (AEOTR) to provide passive target tracking and rangefinding for air to air gun fire control is described. Area correlation processing is used in the comparison of stereo image pairs for stereometric ranging and in the comparison of successive images for tracking. The application of these techniques to the AEOTR, the limitations imposed by packaging, environmental and state-of-the-art sensor and processing hardware constraints, and the projected performance are evaluated. Principal emphasis is given to the use of AEOTR in the gun director engagement mode in which target track and range data is provided to a gun fire control computer. The feasibility of use of the AEOTR to provide target video as an aid to visual target identification, and to provide automatic airborne target detection, is also evaluated. The necessary functions and subsystems are defined and integrated into a preliminary design, whose performance is estimated and compared with the program goals. In addition, a preliminary mounting location study for the F-15, F-16 and F-18 advanced fighters is included. CAI-built hardware was used to successfully demonstrate the feasibility of the ranging and tracking concepts employed in the AEOTR.

  1. A Scintillating Fibre Tracker for MICE

    NASA Astrophysics Data System (ADS)

    Ellis, Malcolm

    The provision of intense stored muon beams would allow the properties of neutrinos to be measured precisely and provide a route to multi-TeV lepton-anti-lepton collisions. The short muon lifetime makes it impossible to employ traditional cooling techniques while maintaining the muon-beam intensity. Ionisation cooling, a process in which the muon beam is passed through a series of liquid hydrogen absorbers followed by accelerating RF-cavities, is the proposed cooling technique. The international Muon Ionisation Cooling Experiment (MICE) collaboration has been approved at the Rutherford Appleton Laboratory and proposes to perform an engineering demonstration of ionisation cooling. The MICE experiment will require the measurement of the momentum and position of muons entering and leaving a section of ionisation cooling channel with high precision and purity in the presence of a large background. The technology chosen to meet this challenge is scintillating fibres readout with Visible Light Photon Detectors. The design, construction and operation of a prototype detector is described, as well as a summary of ongoing research and development activities in preparation for supplying the trackers needed for the MICE experiment.

  2. The DAMPE silicon-tungsten tracker

    NASA Astrophysics Data System (ADS)

    Azzarello, P.; Ambrosi, G.; Asfandiyarov, R.; Bernardini, P.; Bertucci, B.; Bolognini, A.; Cadoux, F.; Caprai, M.; De Mitri, I.; Domenjoz, M.; Dong, Y.; Duranti, M.; Fan, R.; Fusco, P.; Gallo, V.; Gargano, F.; Gong, K.; Guo, D.; Husi, C.; Ionica, M.; La Marra, D.; Loparco, F.; Marsella, G.; Mazziotta, M. N.; Mesa, J.; Nardinocchi, A.; Nicola, L.; Pelleriti, G.; Peng, W.; Pohl, M.; Postolache, V.; Qiao, R.; Surdo, A.; Tykhonov, A.; Vitillo, S.; Wang, H.; Weber, M.; Wu, D.; Wu, X.; Zhang, F.

    2016-09-01

    The DArk Matter Particle Explorer (DAMPE) is a spaceborne astroparticle physics experiment, launched on 17 December 2015. DAMPE will identify possible dark matter signatures by detecting electrons and photons in the 5 GeV-10 TeV energy range. It will also measure the flux of nuclei up to 100 TeV, for the study of the high energy cosmic ray origin and propagation mechanisms. DAMPE is composed of four sub-detectors: a plastic strip scintillator, a silicon-tungsten tracker-converter (STK), a BGO imaging calorimeter and a neutron detector. The STK is composed of six tracking planes of 2 orthogonal layers of single-sided micro-strip detectors, for a total detector surface of ca. 7 m2. The STK has been extensively tested for space qualification. Also, numerous beam tests at CERN have been done to study particle detection at silicon module level, and at full detector level. After description of the DAMPE payload and its scientific mission, we will describe the STK characteristics and assembly. We will then focus on some results of single ladder performance tests done with particle beams at CERN.

  3. 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.

  4. 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.

  5. A Coprocessor for the Fast Tracker Simulation

    NASA Astrophysics Data System (ADS)

    Gentsos, Christos; Volpi, Guido; Gkaitatzis, Stamatios; Giannetti, Paola; Citraro, Saverio; Crescioli, Francesco; Kordas, Kostas; Nikolaidis, Spiridon

    2017-06-01

    The Fast Tracker (FTK) executes real-time tracking for online event selection in the ATLAS experiment. Data processing speed is achieved by exploiting pipelining and parallel processing. Track reconstruction is executed in two stages. The first stage, implemented on custom application-specific integrated circuit (ASICs) called associative memory (AM) chips, performs pattern matching (PM) to identify track candidates in low resolution. The second stage, implemented on field programmable gate arrays (FPGAs), builds on the PM results, performing track fitting in full resolution. The use of such a parallelized architecture for real-time event selection opens up a new, huge computing problem related to the analysis of the acquired samples. Millions of events have to be simulated to determine the efficiency and the properties of the reconstructed tracks with a small statistical error. The AM chip emulation is a computationally intensive task when implemented in software running on commercial resources. This paper proposes the use of a hardware coprocessor to solve this problem efficiently. We report on the implementation and performance of all the functions requiring massive computing power in a modern, compact embedded system for track reconstruction. That system is the miniaturization of the complex FTK processing unit, which is also well suited for powering applications outside the realm of high energy physics.

  6. Evidence of LAT as a dual substrate for Lck and Syk in T lymphocytes.

    PubMed

    Jiang, Yixing; Cheng, Hua

    2007-04-01

    LAT is a linker protein essential for activation of T lymphocytes. Its rapid tyrosine-phosphorylation upon T cell receptor (TCR) stimulation recruits downstream signaling molecules for membrane targeting and activation. LAT is physically concentrated in cholesterol-enriched membrane microdomains and is known a substrate for Syk/Zap70 kinase. In this study, we demonstrate that LAT serves as a dual substrate for both Lck and Syk kinases. LAT phosphorylation is absent in Lck-deficient J.CaM1.6 cells and Lck is co-precipitated with LAT in pervanadate-activated Jurkat cells. Further, the in vitro kinase assay using purified Lck and LAT shows that Lck directly phosphorylates LAT. Both Lck and Syk, phosphorylate the ITAM-like motifs on LAT at Y171Y191, which is essential for induction of the interaction of LAT with downstream signaling molecules such as Grb2, PLC-gamma1 and c-Cbl, and for activation of MAPK-ERK. Collectively, our data indicate that LAT is an immediate substrate for Lck in one of the earliest events of T cell activation.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Optical alignment of the Global Precipitation Measurements (GPM) star trackers

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    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 autocollimation 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.

  12. A Novel Performance Evaluation Methodology for Single-Target Trackers.

    PubMed

    Kristan, Matej; Matas, Jiri; Leonardis, Ales; Vojir, Tomas; Pflugfelder, Roman; Fernandez, Gustavo; Nebehay, Georg; Porikli, Fatih; Cehovin, Luka

    2016-11-01

    This paper addresses the problem of single-target tracker performance evaluation. We consider the performance measures, the dataset and the evaluation system to be the most important components of tracker evaluation and propose requirements for each of them. The requirements are the basis of a new evaluation methodology that aims at a simple and easily interpretable tracker comparison. The ranking-based methodology addresses tracker equivalence in terms of statistical significance and practical differences. A fully-annotated dataset with per-frame annotations with several visual attributes is introduced. The diversity of its visual properties is maximized in a novel way by clustering a large number of videos according to their visual attributes. This makes it the most sophistically constructed and annotated dataset to date. A multi-platform evaluation system allowing easy integration of third-party trackers is presented as well. The proposed evaluation methodology was tested on the VOT2014 challenge on the new dataset and 38 trackers, making it the largest benchmark to date. Most of the tested trackers are indeed state-of-the-art since they outperform the standard baselines, resulting in a highly-challenging benchmark. An exhaustive analysis of the dataset from the perspective of tracking difficulty is carried out. To facilitate tracker comparison a new performance visualization technique is proposed.

  13. 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.

  14. 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.

  15. 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.

  16. Fermi LAT Stacking Analysis of Swift Localized GRBs

    DOE PAGES

    Ackermann, M.; Ajello, M.; Anderson, B.; ...

    2016-05-05

    In this paper, 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 MeVmore » 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. Finally, 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.« less

  17. Flight performance of TOPEX/POSEIDON star trackers

    NASA Astrophysics Data System (ADS)

    Flynn, David J.; Fowski, Walter J.; Kia, Tooraj

    1993-09-01

    The TOPEX/POSEIDON spacecraft was launched on August 10, 1992. This paper presents data on the measured performance of the ASTRA Star Trackers supplied by Hughes Danbury Optical Systems (HDOS) for this satellite. The HDOS ASTRA Star Tracker is a charge coupled device (CCD), microprocessor based replacement for the NASA Standard Fixed Head Star Tracker. The position and magnitude accuracy of the star trackers computed from measured flight data are compared with ground measurements and system models. The performance of novel transient rejection algorithms implemented in the ASTRA Star Tracker which allows uninterrupted operation in the South Atlantic Anomaly (SAA) where the sensor is subjected to high proton flux levels, also are presented.

  18. The Design Parameters for the MICE Tracker Solenoid

    SciTech Connect

    Green, Michael A.; Chen, C.Y.; Juang, Tiki; Lau, Wing W.; Taylor,Clyde; Virostek, Steve P.; Wahrer, Robert; Wang, S.T.; Witte, Holger; Yang, Stephanie Q.

    2006-08-20

    The first superconducting magnets to be installed in the muon ionization cooling experiment (MICE) will be the tracker solenoids. The tracker solenoid module is a five coil superconducting solenoid with a 400 mm diameter warm bore that is used to provide a 4 T magnetic field for the experiment tracker module. Three of the coils are used to produce a uniform field (up to 4 T with better than 1 percent uniformity) in a region that is 300 mm in diameter and 1000 mm long. The other two coils are used to match the muon beam into the MICE cooling channel. Two 2.94-meter long superconducting tracker solenoid modules have been ordered for MICE. The tracker solenoid will be cooled using two-coolers that produce 1.5 W each at 4.2 K. The magnet system is described. The decisions that drive the magnet design will be discussed in this report.

  19. Acceptability of wristband activity trackers among community dwelling older adults.

    PubMed

    O'Brien, Tara; Troutman-Jordan, Meredith; Hathaway, Donna; Armstrong, Shannon; Moore, Michael

    2015-01-01

    Wristband activity trackers have become widely used among young adults. However, few studies have explored their use for monitoring and improving health outcomes among older adults. The purpose of this study was to evaluate the feasibility and utility of activity tracker use among older adults for monitoring activity, improving self-efficacy, and health outcomes. A 12-week pilot study was conducted to evaluate the feasibility and utility of mobile wristband activity trackers. The sample (N = 34) was 65% women 73.5 ± 9.4 years of age who had a high school diploma or GED (38%) and reported an income ≤$35,000 (58%). Participants completing the study (95%) experienced a decrease in waist circumference (p > 0.009), however no change in self-efficacy. Participants found activity trackers easy to use which contributed to minimal study withdrawals. It was concluded that activity trackers could be useful for monitoring and promoting physical activity and improving older adults' health.

  20. 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.

  1. 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.

  2. Passive electro-optical projectiles tracker

    NASA Astrophysics Data System (ADS)

    Agurok, Ilya; Falicoff, Waqidi; Alvarez, Roberto; Shatford, Will

    2012-06-01

    Surveillance, detection, and tracking of multiple high-speed projectiles, particularly bullets, RPGs, and artillery shells, can help military forces immediately locate sources of enemy fire and trigger countermeasures. The traditional techniques for detection and tracing of fast moving objects typically employ various types of radar, which has inherently low resolution for such small objects. Fast moving projectiles are aerodynamically heated up to several hundred degree Kelvin temperatures depending on the speed of a projectile. Thereby, such projectiles radiate in the Mid- Infrared (MWIR) region, where electro-optical resolution is far superior, even to microwave radars. A new passive electro-optical tracker (or PET) uses a two-band IR intensity ratio to obtain a time-varying speed estimate from their time-varying temperatures. Based on an array of time-varying speed data and an array of azimuth/ elevation angles, PET can determines the 3D projectile trajectory and back track it to the source of fire. Various methods are given to determine the vector and range of a projectile, both for clear and for non-homogeneous atmospheric conditions. One approach uses the relative intensity of the image of the projectile on the pixels of a CCD camera to determine the azimuthal angle of trajectory with respect to the ground, and its range. Then by using directions to the tracked projectile (azimuth and elevation angles of the trajectory) and the array of instant projectile speeds, PET determines the distance to the projectile at any point on its tracked trajectory or its predicted trajectory backwards or forwards in time. A second approach uses a least-squares optimization technique over multiple frames based on a triangular representation of the smeared image to yield a real-time trajectory estimate. PET's estimated range accuracy is 0.2 m and the azimuth of the trajectory can be estimated within 0.2°.

  3. 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.

  4. 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 Central

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

    2015-01-01

    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 antisense 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 to its parental virus. Interestingly, although the increased reactivation of McK-ΔH2 compared to its parental wt virus was subtle and only detected at very early times after explant TG induced reactivation, the increased reactivation of dLAT-ΔH2 compared to 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

  5. Herpes simplex virus type 1 serum neutralizing antibody titers increase during latency in rabbits latently infected with latency-associated transcript (LAT)-positive but not LAT-negative viruses.

    PubMed

    Perng, G C; Slanina, S M; Yukht, A; Ghiasi, H; Nesburn, A B; Wechsler, S L

    1999-11-01

    The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) gene is essential for efficient spontaneous reactivation in the rabbit ocular model of HSV-1 latency and reactivation. LAT is also the only viral gene abundantly expressed during latency. Rabbits were ocularly infected with the wild-type HSV-1 strain McKrae or the McKrae-derived LAT null mutant dLAT2903. Serum neutralizing antibody titers were determined at various times during acute and latent infection. The neutralizing antibody titers induced by both viruses increased and were similar throughout the first 45 days after infection (P > 0.05). However, by day 59 postinfection (approximately 31 to 45 days after latency had been established), the neutralizing antibody titers induced by wild-type virus and dLAT2903 diverged significantly (P = 0.0005). The dLAT2903-induced neutralizing antibody titers decreased, while the wild-type virus-induced neutralizing antibody titers continued to increase. A rescuant of dLAT2903, in which spontaneous reactivation was fully restored, induced wild-type neutralizing antibody levels on day 59 postinfection. A second LAT mutant with impaired spontaneous reactivation had neutralizing antibody levels comparable to those of dLAT2903. In contrast to the results obtained in rabbits, in mice, neutralizing antibody titers did not increase over time during latency with any of the viruses. Since LAT is expressed in both rabbits and mice during latency, the difference in neutralizing antibody titers between these animals is unlikely to be due to expression of a LAT protein during latency. In contrast, LAT-positive (LAT(+)), but not LAT-negative (LAT(-)), viruses undergo efficient spontaneous reactivation in rabbits, while neither LAT(+) nor LAT(-) viruses undergo efficient spontaneous reactivation in mice. Thus, the increase in neutralizing antibody titers in rabbits latently infected with LAT(+) viruses may have been due to continued restimulation of the immune system

  6. 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.

  7. Role of the L-amino acid transporter-1 (LAT-1) in mouse trophoblast cell invasion.

    PubMed

    Chrostowski, M K; McGonnigal, B G; Stabila, J P; Padbury, J F

    2010-06-01

    LAT-1 (L-type amino acid transporter 1) is a system L, Na(+)-independent amino acid transporter responsible for transport of large neutral amino acids. Dysregulated expression of LAT-1 is characteristic of many primary human cancers and it's over expression is related to tumor invasion. LAT-1 is highly expressed in the trophoblast giant cells (TGCs) at the time of implantation. Since trophoblast giant cells are highly invasive during the process of endometrial implantation and placentation, LAT-1 may play a role in the invasive phenotype. Our objectives were to identify the effects of increased and decreased LAT-1 expression on mouse trophoblast invasion. We therefore examined the role of amino acid deprivation, pharmacologic blockade specific to leucine transport and gene silencing (siRNA) on LAT-1 expression and trophoblast cell invasion. We utilized mouse primary trophoblast stem (TS) cells. LAT-1 mRNA expression was quantified by real time qPCR, protein by Western blotting and cell invasion was measured in Transwell plates through Matrigel. Amino acid transport using uptake of tritiated leucine. Under limited leucine availability and/or pharmacologic blockage, LAT-1 gene expression was significantly increased, p<0.05. This was associated with a 3-fold increase in cell invasion, p<0.05. In contrast, following siRNA-mediated gene silencing decreased LAT-1 expression (both mRNA and protein) was associated with decreased cell invasion and decreased leucine uptake, p<0.05. Upregulation of LAT-1 gene expression via limited amino acid availability or following pharmacologic blockade of transport leads to an increase in mouse trophoblast stem cell invasiveness. Downregulation of LAT-1 expression via genetic silencing leads to inhibition of invasiveness. These results demonstrate that LAT-1 plays an important role in trophoblast invasion.

  8. Role of the L- amino acid transporter-1 (LAT-1) in Mouse Trophoblast Cell Invasion*

    PubMed Central

    Chrostowski, Magdalena K.; McGonnigal, Bethany G.; Stabila, Joan P.; Padbury, James F.

    2010-01-01

    LAT-1 (L-type amino acid transporter 1) is a system L, Na+-independent amino acid transporter responsible for transport of large neutral amino acids. Dysregulated expression of LAT-1 is characteristic of many primary human cancers and it’s over expression is related to tumor invasion. LAT-1 is highly expressed in the trophoblast giant cells (TGCs) at the time of implantation. Since trophoblast giant cells are highly invasive during the process of endometrial implantation and placentation, LAT-1 may play a role in the invasive phenotype. Our objectives were to identify the effects of increased and decreased LAT-1 expression on mouse trophoblast invasion. We therefore examined the role of amino acid deprivation, pharmacologic blockade specific to leucine transport and gene silencing (siRNA) on LAT-1 expression and trophoblast cell invasion. We utilized mouse primary trophoblast stem (TS) cells. LAT-1 mRNA expression was quantified by real-time qPCR, protein by Western blotting and cell invasion was measured in Transwell plates through Matrigel. Amino acid transport using uptake of tritiated leucine. Under limited leucine availability and/or pharmacologic blockage, LAT-1 gene expression was significantly increased, p<0.05. This was associated with a 3-fold increase in cell invasion, p<0.05. In contrast, following siRNA-mediated gene silencing decreased LAT-1 expression (both mRNA and protein) was associated with decreased cell invasion and decreased leucine uptake, p<0.05. Upregulation of LAT-1 gene expression via limited amino acid availability or following pharmacologic blockade of transport leads to an increase in mouse trophoblast stem cell invasiveness. Downregulation of LAT-1 expression via genetic silencing leads to inhibition of invasiveness. These results demonstrate that LAT-1 plays an important role in trophoblast invasion. PMID:20421131

  9. Wind Load Analysis of A Solar Tracker For Concentrator Photovoltaics

    NASA Astrophysics Data System (ADS)

    Wu, Jiunn-Chi; Lin, Kuan-Hung; Lin, Chih-Kuang

    2010-10-01

    This work studied the air flow over a two-axis solar tracker with two CPV modules installed. Both the velocity distribution and wind load were analyzed in order to quantify the effects of elevation angle and wind speed on the structural strength of tracker. The air flow is simulated as turbulent, incompressible flow upto 30 m/s and the κ-ɛ turbulence model is utilized for characterizing the flow turbulence. The range of elevation angle is varied between 0° to 90°. As the elevation angle increases, the wind load on the tracker reduces, and large recirculation zone and the suction pressure field are identified on the leeward side of the tracker. The maximum wind load always located on the pedestal of tracker. As the elevation angle decreases, the pedestal experiences increasing wind load. Such wind load distribution on the CPV modules and tracker has been used as the load-input for analyzing the structural deformation of the whole system (CPV modules and tracker). This deformation causes different levels of off-set angle on the CPV module which may reduce the tracking accuracy and degrade the electricity output of CPV system.

  10. The LATS2 tumor suppressor inhibits SREBP and suppresses hepatic cholesterol accumulation.

    PubMed

    Aylon, Yael; Gershoni, Anat; Rotkopf, Ron; Biton, Inbal E; Porat, Ziv; Koh, Anna P; Sun, Xiaochen; Lee, Youngmin; Fiel, Maria-Isabel; Hoshida, Yujin; Friedman, Scott L; Johnson, Randy L; Oren, Moshe

    2016-04-01

    The Hippo signaling pathway is a major regulator of organ size. In the liver, Hippo pathway deregulation promotes hyperplasia and hepatocellular carcinoma primarily through hyperactivation of its downstream effector, YAP. The LATS2 tumor suppressor is a core member of the Hippo pathway. A screen for LATS2-interacting proteins in liver-derived cells identified the transcription factor SREBP2, master regulator of cholesterol homeostasis. LATS2 down-regulation caused SREBP activation and accumulation of excessive cholesterol. Likewise, mice harboring liver-specific Lats2 conditional knockout (Lats2-CKO) displayed constitutive SREBP activation and overexpressed SREBP target genes and developed spontaneous fatty liver disease. Interestingly, the impact of LATS2 depletion on SREBP-mediated transcription was clearly distinct from that of YAP overexpression. When challenged with excess dietary cholesterol, Lats2-CKO mice manifested more severe liver damage than wild-type mice. Surprisingly, apoptosis, inflammation, and fibrosis were actually attenuated relative to wild-type mice, in association with impaired p53 activation. Subsequently, Lats2-CKO mice failed to recover effectively from cholesterol-induced damage upon return to a normal diet. Additionally, decreased LATS2 mRNA in association with increased SREBP target gene expression was observed in a subset of human nonalcoholic fatty liver disease cases. Together, these findings further highlight the tight links between tumor suppressors and metabolic homeostasis.

  11. Role of LAT in the Granule-Mediated Cytotoxicity of CD8 T Cells

    PubMed Central

    Ou-Yang, Chih-wen; Zhu, Minghua; Fuller, Deirdre M.; Sullivan, Sarah A.; Chuck, Mariana I.; Ogden, Sarah

    2012-01-01

    Linker for activation of T cells (LAT) is a transmembrane adaptor protein that is essential to bridge T cell receptor (TCR) engagement to downstream signaling events. The indispensable role of LAT in thymocyte development and T cell activation has been well characterized; however, the function of LAT in cytotoxic-T-lymphocyte (CTL) cytotoxicity remains unknown. We show here that LAT-deficient CTLs failed to upregulate FasL and produce gamma interferon after engagement with target cells and had impaired granule-mediated killing. We further dissected the effect of the LAT deletion on each step of granule exocytosis. LAT deficiency led to altered synapse formation, subsequently causing unstable T cell–antigen-presenting cell (APC) conjugates. Microtubule organizing center polarization and granule reorientation were also impaired by LAT deficiency, leading to reduced granule delivery. Despite these defects, granule release was still observed in LAT-deficient CTLs due to residual calcium flux and phospholipase C (PLC) activity. Our data demonstrated that LAT-mediated signaling intricately regulates CTL cytotoxicity at multiple steps. PMID:22566687

  12. The LATS2 tumor suppressor inhibits SREBP and suppresses hepatic cholesterol accumulation

    PubMed Central

    Aylon, Yael; Gershoni, Anat; Rotkopf, Ron; Biton, Inbal E.; Porat, Ziv; Koh, Anna P.; Sun, Xiaochen; Lee, Youngmin; Fiel, Maria-Isabel; Hoshida, Yujin; Friedman, Scott L.; Johnson, Randy L.; Oren, Moshe

    2016-01-01

    The Hippo signaling pathway is a major regulator of organ size. In the liver, Hippo pathway deregulation promotes hyperplasia and hepatocellular carcinoma primarily through hyperactivation of its downstream effector, YAP. The LATS2 tumor suppressor is a core member of the Hippo pathway. A screen for LATS2-interacting proteins in liver-derived cells identified the transcription factor SREBP2, master regulator of cholesterol homeostasis. LATS2 down-regulation caused SREBP activation and accumulation of excessive cholesterol. Likewise, mice harboring liver-specific Lats2 conditional knockout (Lats2-CKO) displayed constitutive SREBP activation and overexpressed SREBP target genes and developed spontaneous fatty liver disease. Interestingly, the impact of LATS2 depletion on SREBP-mediated transcription was clearly distinct from that of YAP overexpression. When challenged with excess dietary cholesterol, Lats2-CKO mice manifested more severe liver damage than wild-type mice. Surprisingly, apoptosis, inflammation, and fibrosis were actually attenuated relative to wild-type mice, in association with impaired p53 activation. Subsequently, Lats2-CKO mice failed to recover effectively from cholesterol-induced damage upon return to a normal diet. Additionally, decreased LATS2 mRNA in association with increased SREBP target gene expression was observed in a subset of human nonalcoholic fatty liver disease cases. Together, these findings further highlight the tight links between tumor suppressors and metabolic homeostasis. PMID:27013235

  13. Coalitional Tracker for Deception Detection in Thermal Imagery

    NASA Astrophysics Data System (ADS)

    Dowdall, Jonathan; Pavlidis, Ioannis; Tsiamyrtzis, Panagiotis

    We propose a novel tracking method that uses a network of independent particle filter trackers whose interactions are modeled using coalitional game theory. Our tracking method is general; it maintains pixel-level accuracy, and can negotiate surface deformations and occlusions. We tested our method in a substantial video set featuring nontrivial motion from over 40 objects in both the infrared and vi sual spectra. The coalitional tracker demonstrated fault-tolerant behavior that far exceeds the performance of single-particle filter trackers. Our method represents a shift from the typical tracking paradigms and may find application in demanding imaging problems across the electromagnetic spectrum.

  14. 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.

  15. 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.

  16. Status of the D0 fiber tracker and preshower detectors

    SciTech Connect

    Smirnov, Dmitri; /Notre Dame U.

    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.

  17. A Bayesian tracker for multi-sensor passive narrowband fusion

    NASA Astrophysics Data System (ADS)

    Pirkl, Ryan J.; Aughenbaugh, Jason M.

    2016-05-01

    We demonstrate the detection and localization performance of a multi-sensor, passive sonar Bayesian tracker for underwater targets emitting narrowband signals in the presence of realistic underwater ambient noise. Our evaluation focuses on recent advances in the formulation of the likelihood function used by the tracker that provide greater robustness in the presence of both realistic environmental noise and imprecise/inaccurate a priori knowledge of the target's narrowband signal. These improvements enable the tracker to reliably detect and localize narrowband emitters for a broader range of propagation environments, target velocities, and inherent uncertainty in a priori knowledge.

  18. 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.

  19. Data acquisition software for the CMS strip tracker

    NASA Astrophysics Data System (ADS)

    Bainbridge, R.; Baulieu, G.; Bel, S.; Cole, J.; Cripps, N.; Delaere, C.; Jesus, A. C. A.; Drouhin, F.; Fulcher, J.; Giassi, A.; Gill, K.; Giordano, D.; Gross, L.; Hahn, K.; Mersi, S.; Mirabito, L.; Nikolic, M.; Radicci, V.; Tkaczyk, S.; Wingham, M.

    2008-07-01

    The CMS silicon strip tracker, providing a sensitive area of approximately 200 m2 and comprising 10 million readout channels, has recently been completed at the tracker integration facility at CERN. The strip tracker community is currently working to develop and integrate the online and offline software frameworks, known as XDAQ and CMSSW respectively, for the purposes of data acquisition and detector commissioning and monitoring. Recent developments have seen the integration of many new services and tools within the online data acquisition system, such as event building, online distributed analysis, an online monitoring framework, and data storage management. We review the various software components that comprise the strip tracker data acquisition system, the software architectures used for stand-alone and global data-taking modes. Our experiences in commissioning and operating one of the largest ever silicon micro-strip tracking systems are also reviewed.

  20. 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.

  1. A single beam laser tracker as an alignment tool

    SciTech Connect

    Wand, B.T.; LeCocq, C.; Gaydosh, M.; Ruland, R.E.

    1992-07-01

    In December 1991 the Survey and Alignment team of the Stanford Liner Accelerator Center (SLAC) purchased a Chesapeake single beam laser tracker. This paper will discuss first experiences and applications with this new type of an alignment instrument.

  2. 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.

  3. 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.

  4. Grumman S2F-1 Tracker at NACA Lewis

    NASA Image and Video Library

    1956-08-21

    The NACA’s Lewis Flight Propulsion Laboratory acquired the Grumman S2F-1 Tracker from the Navy in 1955 to study icing instrumentation. Lewis’s icing research program was winding down at the time. The use of jet engines was increasing thus reducing the threat of ice accumulation. Nonetheless Lewis continued research on the instrumentation used to detect icing conditions. The S2F-1 Tracker was a carrier-based submarine hunter for the Navy. Grumman developed the Tracker as a successor to its Korean War-era Guardian patrol aircraft. Prototypes first flew in late 1952 and battle-ready versions entered Naval service in early 1954. The Navy utilized the Trackers to protect fleets from attack.

  5. Performance of the ATLAS Transition Radiation Tracker in Run 1 of the LHC: tracker properties

    DOE PAGES

    Aaboud, M.; Aad, G.; Abbott, B.; ...

    2017-05-03

    The tracking performance parameters of the ATLAS Transition Radiation Tracker (TRT) as part of the ATLAS inner detector are described in this paper for different data-taking conditions in proton-proton, proton-lead and lead-lead collisions at the Large Hadron Collider (LHC). The performance is studied using data collected during the first period of LHC operation (Run 1) and is compared with Monte Carlo simulations. The performance of the TRT, operating with two different gas mixtures (xenon-based and argon-based) and its dependence on the TRT occupancy is presented. Furthermore, these studies show that the tracking performance of the TRT is similar for themore » two gas mixtures and that a significant contribution to the particle momentum resolution is made by the TRT up to high particle densities.« less

  6. Performance of the ATLAS Transition Radiation Tracker in Run 1 of the LHC: tracker properties

    NASA Astrophysics Data System (ADS)

    Aaboud, M.; Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Abeloos, B.; Abidi, S. H.; AbouZeid, O. S.; Abraham, N. L.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adachi, S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adersberger, M.; Adye, T.; Affolder, A. A.; Agatonovic-Jovin, T.; Agheorghiesei, C.; Aguilar-Saavedra, J. A.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akatsuka, S.; Akerstedt, H.; Åkesson, T. P. A.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Alconada Verzini, M. J.; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexopoulos, T.; Alhroob, M.; Ali, B.; Aliev, M.; Alimonti, G.; Alison, J.; Alkire, S. P.; Allbrooke, B. M. M.; Allen, B. W.; Allport, P. P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Alshehri, A. A.; Alstaty, M.; Alvarez Gonzalez, B.; Álvarez Piqueras, D.; Alviggi, M. G.; Amadio, B. T.; Amaral Coutinho, Y.; Amelung, C.; Amidei, D.; Amor Dos Santos, S. P.; Amorim, A.; Amoroso, S.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, J. K.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Angelidakis, S.; Angelozzi, I.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antel, C.; Antonelli, M.; Antonov, A.; Antrim, D. J.; Anulli, F.; Aoki, M.; Aperio Bella, L.; Arabidze, G.; Arai, Y.; Araque, J. P.; Araujo Ferraz, V.; Arce, A. T. H.; Ardell, R. E.; Arduh, F. A.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Armitage, L. J.; Arnaez, O.; Arnold, H.; Arratia, M.; Arslan, O.; Artamonov, A.; Artoni, G.; Artz, S.; Asai, S.; Asbah, N.; Ashkenazi, A.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Augsten, K.; Avolio, G.; Axen, B.; Ayoub, M. K.; Azuelos, G.; Baas, A. E.; Baca, M. J.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Bagiacchi, P.; Bagnaia, P.; Baines, J. T.; Bajic, M.; Baker, O. K.; Baldin, E. M.; Balek, P.; Balestri, T.; Balli, F.; Balunas, W. K.; Banas, E.; Banerjee, Sw.; Bannoura, A. A. E.; Barak, L.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisits, M.-S.; Barklow, T.; Barlow, N.; Barnes, S. L.; Barnett, B. M.; Barnett, R. M.; Barnovska-Blenessy, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barranco Navarro, L.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Bartoldus, R.; Barton, A. E.; Bartos, P.; Basalaev, A.; Bassalat, A.; Bates, R. L.; Batista, S. J.; Batley, J. R.; Battaglia, M.; Bauce, M.; Bauer, F.; Bawa, H. S.; Beacham, J. B.; Beattie, M. D.; Beau, T.; Beauchemin, P. H.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, M.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bedognetti, M.; Bee, C. P.; Beermann, T. A.; Begalli, M.; Begel, M.; Behr, J. K.; Bell, A. S.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belotskiy, K.; Beltramello, O.; Belyaev, N. L.; Benary, O.; Benchekroun, D.; Bender, M.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez, J.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Bentvelsen, S.; Beresford, L.; Beretta, M.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Beringer, J.; Berlendis, S.; Bernard, N. R.; Bernardi, G.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertoli, G.; Bertolucci, F.; Bertram, I. A.; Bertsche, C.; Bertsche, D.; Besjes, G. J.; Bessidskaia Bylund, O.; Bessner, M.; Besson, N.; Betancourt, C.; Bethani, A.; Bethke, S.; Bevan, A. J.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Biedermann, D.; Bielski, R.; Biesuz, N. V.; Biglietti, M.; Bilbao De Mendizabal, J.; Billoud, T. R. V.; Bilokon, H.; Bindi, M.; Bingul, A.; Bini, C.; Biondi, S.; Bisanz, T.; Bittrich, C.; Bjergaard, D. M.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blazek, T.; Bloch, I.; Blocker, C.; Blue, A.; Blum, W.; Blumenschein, U.; Blunier, S.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Bock, C.; Boehler, M.; Boerner, D.; Bogavac, D.; Bogdanchikov, A. G.; Bohm, C.; Boisvert, V.; Bokan, P.; Bold, T.; Boldyrev, A. S.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Bortfeldt, J.; Bortoletto, D.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Bossio Sola, J. D.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Boutle, S. K.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bracinik, J.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Breaden Madden, W. D.; Brendlinger, K.; Brennan, A. J.; Brenner, L.; Brenner, R.; Bressler, S.; Briglin, D. L.; Bristow, T. M.; Britton, D.; Britzger, D.; Brochu, F. M.; Brock, I.; Brock, R.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Broughton, J. H.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruni, A.; Bruni, G.; Bruni, L. 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C.; Taylor, G. N.; Taylor, P. T. E.; Taylor, W.; Teixeira-Dias, P.; Temming, K. K.; Temple, D.; Ten Kate, H.; Teng, P. K.; Teoh, J. J.; Tepel, F.; Terada, S.; Terashi, K.; Terron, J.; Terzo, S.; Testa, M.; Teuscher, R. J.; Theveneaux-Pelzer, T.; Thomas, J. P.; Thomas-Wilsker, J.; Thompson, P. D.; Thompson, A. S.; Thomsen, L. A.; Thomson, E.; Tibbetts, M. J.; Ticse Torres, R. E.; Tikhomirov, V. O.; Tikhonov, Yu. A.; Timoshenko, S.; Tipton, P.; Tisserant, S.; Todome, K.; Todorova-Nova, S.; Tojo, J.; Tokár, S.; Tokushuku, K.; Tolley, E.; Tomlinson, L.; Tomoto, M.; Tompkins, L.; Toms, K.; Tong, B.; Tornambe, P.; Torrence, E.; Torres, H.; Torró Pastor, E.; Toth, J.; Touchard, F.; Tovey, D. R.; Treado, C. J.; Trefzger, T.; Tricoli, A.; Trigger, I. M.; Trincaz-Duvoid, S.; Tripiana, M. F.; Trischuk, W.; Trocmé, B.; Trofymov, A.; Troncon, C.; Trottier-McDonald, M.; Trovatelli, M.; Truong, L.; Trzebinski, M.; Trzupek, A.; Tsang, K. W.; Tseng, J. C.-L.; Tsiareshka, P. V.; Tsipolitis, G.; Tsirintanis, N.; Tsiskaridze, S.; Tsiskaridze, V.; Tskhadadze, E. G.; Tsui, K. M.; Tsukerman, I. I.; Tsulaia, V.; Tsuno, S.; Tsybychev, D.; Tu, Y.; Tudorache, A.; Tudorache, V.; Tulbure, T. T.; Tuna, A. N.; Tupputi, S. A.; Turchikhin, S.; Turgeman, D.; Turk Cakir, I.; Turra, R.; Tuts, P. M.; Ucchielli, G.; Ueda, I.; Ughetto, M.; Ukegawa, F.; Unal, G.; Undrus, A.; Unel, G.; Ungaro, F. C.; Unno, Y.; Unverdorben, C.; Urban, J.; Urquijo, P.; Urrejola, P.; Usai, G.; Usui, J.; Vacavant, L.; Vacek, V.; Vachon, B.; Valderanis, C.; Valdes Santurio, E.; Valencic, N.; Valentinetti, S.; Valero, A.; Valery, L.; Valkar, S.; Vallier, A.; Valls Ferrer, J. A.; Van Den Wollenberg, W.; van der Graaf, H.; van Eldik, N.; van Gemmeren, P.; Van Nieuwkoop, J.; van Vulpen, I.; van Woerden, M. C.; Vanadia, M.; Vandelli, W.; Vanguri, R.; Vaniachine, A.; Vankov, P.; Vardanyan, G.; Vari, R.; Varnes, E. W.; Varni, C.; Varol, T.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vasquez, J. G.; Vasquez, G. A.; Vazeille, F.; Vazquez Schroeder, T.; Veatch, J.; Veeraraghavan, V.; Veloce, L. M.; Veloso, F.; Veneziano, S.; Ventura, A.; Venturi, M.; Venturi, N.; Venturini, A.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vetterli, M. C.; Viaux Maira, N.; Viazlo, O.; Vichou, I.; Vickey, T.; Boeriu, O. E. Vickey; Viehhauser, G. H. A.; Viel, S.; Vigani, L.; Villa, M.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M. G.; Vinogradov, V. B.; Vishwakarma, A.; Vittori, C.; Vivarelli, I.; Vlachos, S.; Vlasak, M.; Vogel, M.; Vokac, P.; Volpi, G.; Volpi, M.; von der Schmitt, H.; von Toerne, E.; Vorobel, V.; Vorobev, K.; Vos, M.; Voss, R.; Vossebeld, J. H.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Vuillermet, R.; Vukotic, I.; Wagner, P.; Wagner, W.; Wahlberg, H.; Wahrmund, S.; Wakabayashi, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wallangen, V.; Wang, C.; Wang, C.; Wang, F.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, Q.; Wang, R.; Wang, S. M.; Wang, T.; Wang, W.; Wang, W.; Wanotayaroj, C.; Warburton, A.; Ward, C. P.; Wardrope, D. R.; Washbrook, A.; Watkins, P. M.; Watson, A. T.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, B. M.; Webb, A. F.; Webb, S.; Weber, M. S.; Weber, S. W.; Weber, S. A.; Webster, J. S.; Weidberg, A. R.; Weinert, B.; Weingarten, J.; Weiser, C.; Weits, H.; Wells, P. S.; Wenaus, T.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M. D.; Werner, P.; Wessels, M.; Whalen, K.; Whallon, N. L.; Wharton, A. M.; White, A.; White, M. J.; White, R.; Whiteson, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wiglesworth, C.; Wiik-Fuchs, L. A. M.; Wildauer, A.; Wilk, F.; Wilkens, H. G.; Williams, H. H.; Williams, S.; Willis, C.; Willocq, S.; Wilson, J. A.; Wingerter-Seez, I.; Winklmeier, F.; Winston, O. J.; Winter, B. T.; Wittgen, M.; Wobisch, M.; Wolf, T. M. H.; Wolff, R.; Wolter, M. W.; Wolters, H.; Worm, S. D.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wozniak, K. W.; Wu, M.; Wu, S. L.; Wu, X.; Wu, Y.; Wyatt, T. R.; Wynne, B. M.; Xella, S.; Xi, Z.; Xia, L.; Xu, D.; Xu, L.; Yabsley, B.; Yacoob, S.; Yamaguchi, D.; Yamaguchi, Y.; Yamamoto, A.; Yamamoto, S.; Yamanaka, T.; Yamauchi, K.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, H.; Yang, Y.; Yang, Z.; Yao, W.-M.; Yap, Y. C.; Yasu, Y.; Yatsenko, E.; Yau Wong, K. H.; Ye, J.; Ye, S.; Yeletskikh, I.; Yildirim, E.; Yorita, K.; Yoshihara, K.; Young, C.; Young, C. J. S.; Youssef, S.; Yu, D. R.; Yu, J.; Yu, J.; Yuan, L.; Yuen, S. P. Y.; Yusuff, I.; Zabinski, B.; Zacharis, G.; Zaidan, R.; Zaitsev, A. M.; Zakharchuk, N.; Zalieckas, J.; Zaman, A.; Zambito, S.; Zanzi, D.; Zeitnitz, C.; Zeman, M.; Zemla, A.; Zeng, J. C.; Zeng, Q.; Zenin, O.; Ženiš, T.; Zerwas, D.; Zhang, D.; Zhang, F.; Zhang, G.; Zhang, H.; Zhang, J.; Zhang, L.; Zhang, L.; Zhang, M.; Zhang, R.; Zhang, R.; Zhang, X.; Zhang, Y.; Zhang, Z.; Zhao, X.; Zhao, Y.; Zhao, Z.; Zhemchugov, A.; Zhong, J.; Zhou, B.; Zhou, C.; Zhou, L.; Zhou, M.; Zhou, M.; Zhou, N.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zhukov, K.; Zibell, A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, S.; Zinonos, Z.; Zinser, M.; Ziolkowski, M.; Živković, L.; Zobernig, G.; Zoccoli, A.; Zou, R.; zur Nedden, M.; Zwalinski, L.

    2017-05-01

    The tracking performance parameters of the ATLAS Transition Radiation Tracker (TRT) as part of the ATLAS inner detector are described in this paper for different data-taking conditions in proton-proton, proton-lead and lead-lead collisions at the Large Hadron Collider (LHC). The performance is studied using data collected during the first period of LHC operation (Run 1) and is compared with Monte Carlo simulations. The performance of the TRT, operating with two different gas mixtures (xenon-based and argon-based) and its dependence on the TRT occupancy is presented. These studies show that the tracking performance of the TRT is similar for the two gas mixtures and that a significant contribution to the particle momentum resolution is made by the TRT up to high particle densities.

  7. 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.

  8. A new accelerator alignment concept using laser trackers

    SciTech Connect

    Friedsam, H.

    1994-07-01

    This paper outlines the basic principle of the laser tracker and the new and simplified alignment concept for the APS based on the use of these laser trackers. These instruments not only provide the necessary accuracy for positioning of beam components but are also reducing the time and manpower requirements for the alignment of beam elements. The presented alignment concept will be especially valuable when considering the alignment of small scale accelerators.

  9. 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.

  10. 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.

  11. Design of a sun tracker for a laser heterodyne spectrometer

    NASA Astrophysics Data System (ADS)

    Delahaigue, A.; Thiebeaux, C.; Courtois, D.; Le Corre, H.

    1988-01-01

    A sun tracker with a tracking precision of 0.001 degree has been developed for use with a high-resolution Laser Heterodyne Spectrometer. The mechanical and optical arrangement of the tracker are described in detail, in addition to the tracking software. The system was used to record ozone atmospheric spectra in the 10-micron region in March 1987. The analysis range is + or - 1220 MHz.

  12. Software and mathematical support of Kazakhstani star tracker

    NASA Astrophysics Data System (ADS)

    Akhmedov, D.; Yelubayev, S.; Ten, V.; Bopeyev, T.; Alipbayev, K.; Sukhenko, A.

    2016-10-01

    Currently the specialists of Kazakhstan have been developing the star tracker that is further planned to use on Kazakhstani satellites of various purposes. At the first stage it has been developed the experimental model of star tracker that has following characteristics: field of view 20°, update frequency 2 Hz, exclusion angle 40°, accuracy of attitude determination of optical axis/around optical axis 15/50 arcsec. Software and mathematical support are the most high technology parts of star tracker. The results of software and mathematical support development of experimental model of Kazakhstani star tracker are represented in this article. In particular, there are described the main mathematical models and algorithms that have been used as a basis for program units of preliminary image processing of starry sky, stars identification and star tracker attitude determination. The results of software and mathematical support testing with the help of program simulation complex using various configurations of defects including image sensor noises, point spread function modeling, optical system distortion up to 2% are presented. Analysis of testing results has shown that accuracy of attitude determination of star tracker is within the permissible range

  13. 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.

  14. Endoscope-magnetic tracker calibration via trust region optimization

    NASA Astrophysics Data System (ADS)

    Sargent, Dusty

    2010-02-01

    Minimally invasive surgical techniques and advanced imaging systems are gaining prevalence in modern clinical practice. Using miniaturized magnetic trackers in combination with these procedures can help physicians with the orientation and guidance of instruments in graphical displays, navigation during surgery, 3D reconstruction of anatomy, and other applications. Magnetic trackers are often used in conjunction with other sensors or instruments such as endoscopes and optical trackers. In such applications, complex calibration procedures are required to align the coordinate systems of the different devices in order to produce accurate results. Unfortunately, current calibration procedures developed for augmented reality are cumbersome and unsuitable for repeated use in a clinical setting. This paper presents an efficient automated endoscope-tracker calibration algorithm for clinical applications. The algorithm is based on a state-of-the-art trust region optimization method and requires minimal intervention from the endoscope operator. The only required input is a short video of a calibration grid taken with the endoscope and attached magnetic tracker prior to the procedure. The three stage calibration process uses a traditional camera calibration to determine the intrinsic and extrinsic parameters of the endoscope, and then the endoscope is registered in the tracker's reference frame using a novel linear estimation method and a trust region optimization algorithm. This innovative method eliminates the need for complicated calibration procedures and facilitates the use of magnetic tracking devices in clinical settings.

  15. Breadboard stellar tracker system test report, volume 1

    NASA Astrophysics Data System (ADS)

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

    1981-08-01

    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.

  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. 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.

  18. Herpes Simplex Virus Type 1 Serum Neutralizing Antibody Titers Increase during Latency in Rabbits Latently Infected with Latency-Associated Transcript (LAT)-Positive but Not LAT-Negative Viruses

    PubMed Central

    Perng, Guey-Chuen; Slanina, Susan M.; Yukht, Ada; Ghiasi, Homayon; Nesburn, Anthony B.; Wechsler, Steven L.

    1999-01-01

    The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) gene is essential for efficient spontaneous reactivation in the rabbit ocular model of HSV-1 latency and reactivation. LAT is also the only viral gene abundantly expressed during latency. Rabbits were ocularly infected with the wild-type HSV-1 strain McKrae or the McKrae-derived LAT null mutant dLAT2903. Serum neutralizing antibody titers were determined at various times during acute and latent infection. The neutralizing antibody titers induced by both viruses increased and were similar throughout the first 45 days after infection (P > 0.05). However, by day 59 postinfection (approximately 31 to 45 days after latency had been established), the neutralizing antibody titers induced by wild-type virus and dLAT2903 diverged significantly (P = 0.0005). The dLAT2903-induced neutralizing antibody titers decreased, while the wild-type virus-induced neutralizing antibody titers continued to increase. A rescuant of dLAT2903, in which spontaneous reactivation was fully restored, induced wild-type neutralizing antibody levels on day 59 postinfection. A second LAT mutant with impaired spontaneous reactivation had neutralizing antibody levels comparable to those of dLAT2903. In contrast to the results obtained in rabbits, in mice, neutralizing antibody titers did not increase over time during latency with any of the viruses. Since LAT is expressed in both rabbits and mice during latency, the difference in neutralizing antibody titers between these animals is unlikely to be due to expression of a LAT protein during latency. In contrast, LAT-positive (LAT+), but not LAT-negative (LAT−), viruses undergo efficient spontaneous reactivation in rabbits, while neither LAT+ nor LAT− viruses undergo efficient spontaneous reactivation in mice. Thus, the increase in neutralizing antibody titers in rabbits latently infected with LAT+ viruses may have been due to continued restimulation of the immune system by

  19. Amino acid transporter LAT3 is required for podocyte development and function.

    PubMed

    Sekine, Yuji; Nishibori, Yukino; Akimoto, Yoshihiro; Kudo, Akihiko; Ito, Noriko; Fukuhara, Daisuke; Kurayama, Ryota; Higashihara, Eiji; Babu, Ellappan; Kanai, Yoshikatsu; Asanuma, Katsuhiko; Nagata, Michio; Majumdar, Arindam; Tryggvason, Karl; Yan, Kunimasa

    2009-07-01

    LAT3 is a Na+-independent neutral l-amino acid transporter recently isolated from a human hepatocellular carcinoma cell line. Although liver, skeletal muscle, and pancreas are known to express LAT3, the tissue distribution and physiologic function of this transporter are not completely understood. Here, we observed that glomeruli express LAT3. Immunofluorescence, confocal microscopy, and immunoelectron microscopy revealed that LAT3 localizes to the apical plasma membrane of podocyte foot processes. In mice, starvation upregulated glomerular LAT3, phosphorylated AKT1, reconstituted the actin network, and elongated foot processes. In the fetal kidney, we observed intense LAT3 expression at the capillary loops stage of renal development. Finally, zebrafish morphants lacking lat3 function showed collapsed glomeruli with thickened glomerular basement membranes. Permeability studies of the glomerular filtration barrier in these zebrafish morphants demonstrated a disruption of selective glomerular permeability. Our data suggest that LAT3 may play a crucial role in the development and maintenance of podocyte structure and function by regulating protein synthesis and the actin cytoskeleton.

  20. 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.

  1. Serine residues in the LAT adaptor are essential for TCR-dependent signal transduction.

    PubMed

    Martínez-Florensa, Mario; García-Blesa, Antonio; Yélamos, José; Muñoz-Suano, Alba; Domínguez-Villar, Margarita; Valdor, Rut; Alonso, Antonio; García-Cózar, Francisco; Aparicio, Pedro; Malissen, Bernard; Aguado, Enrique

    2011-01-01

    The adaptor protein LAT has a prominent role in the transduction of intracellular signals elicited by the TCR/CD3 complex. Upon TCR engagement, LAT becomes tyrosine-phosphorylated and thereby, recruits to the membrane several proteins implicated in the activation of downstream signaling pathways. However, little is known about the role of other conserved motifs present in the LAT sequence. Here, we report that the adaptor LAT contains several conserved serine-based motifs, which are essential for proper signal transduction through the TCR. Mutation of these serine motifs in the human T cell line Jurkat prevents proper calcium influx, MAPK activation, and IL-2 production in response to TCR/CD3 stimulation. Moreover, this mutant form of LAT has a reduced ability to bind to PLC-γ1 and SLP-76, although phosphorylation of tyrosine residues 132, 171, and 191 is not decreased, raising a possible role for the serine-based motifs of LAT for the binding of important partners. The functional role of LAT serine-based motifs in signal transduction could be mediated by an effect on tyrosine phosphorylation, as their mutation significantly diminishes the phosphorylation of tyrosine residue 226. In addition, these serine motifs seem to have a regulatory role, given that upon their mutation, ZAP-70 shows enhanced phosphorylation. Therefore, the LAT serine-based motifs likely regulate signaling pathways that are essential for T cell physiology.

  2. 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

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

    PubMed

    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

    2015-07-02

    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.

  4. Dietary protein, energy and arginine affect LAT1 expression in forebrain white matter differently.

    PubMed

    Wu, X; Yin, Y L; Li, T J; Wang, L; Ruan, Z; Liu, Z Q; Hou, Y Q

    2010-09-01

    L-type amino acid transporter-1 (LAT1) transports large, branched-chain, aromatic and neutral amino acids. About 64 Duroc × Landrace × Yorkshire pigs were used to study the effects of dietary crude protein (CP), energy and arginine on LAT1 expression in forebrain. The results showed that LAT1 expression in forebrain was sensitive to different levels of CP, energy and arginine. On the basis of Western blot analysis, a lower level of LAT1 presented in the brain tissues of pigs fed the low dietary CP diet (P < 0.05), a higher level were found in pigs fed the higher CP diet, with moderate to intense staining seen in pigs fed the diet plus 1% arginine. In contrast, pigs fed the control-energy diet had weak LAT1 expression, and those fed the diet supplemented with 1% arginine showed lowest LAT1 expression (P < 0.05). These results showed that LAT1 was highly expressed in the forebrain, and expression of LAT1 was affected by dietary protein, energy and arginine differently.

  5. LAB/NTAL/Lat2: a force to be reckoned with in all leukocytes?

    PubMed Central

    Orr, Selinda J.; McVicar, Daniel W.

    2011-01-01

    LAB/NTAL/Lat2 is a transmembrane adaptor protein closely related to LAT. It is expressed in various myeloid and lymphoid cells, many of which also express LAT. Phosphorylation of LAB occurs following engagement of various ITAM- and non-ITAM-linked receptors and can play positive and negative roles following receptor engagement. LAT binds PLCγ directly, resulting in efficient Ca2+ flux and degranulation. However, LAB does not contain a PLCγ-binding motif and only binds PLCγ indirectly, possibly via Grb2, thereby resulting in suboptimal signaling. As LAT can signal more efficiently than LAB, competition between the 2 for space/substrates in the lipid rafts can attenuate signaling. This competition model requires coexpression of LAT; however, LAB is repressive, even in cells lacking substantial LAT expression such as macrophages and mature B cells. The reported interaction between LAB and the ubiquitin E3-ligase c-Cbl suggests 1 possible mechanism for LAT-independent inhibition by LAB, but such a model requires further investigation. Given the wide-reaching expression pattern of LAB, LAB has the ability to modulate signaling in virtually every type of leukocyte. Regardless of its ultimate mode of action, the potent regulatory capability of LAB proves this protein to be a complex adaptor that warrants continued, substantial scrutiny by biochemists and immunologists alike. PMID:20643813

  6. LAB/NTAL/Lat2: a force to be reckoned with in all leukocytes?

    PubMed

    Orr, Selinda J; McVicar, Daniel W

    2011-01-01

    LAB/NTAL/Lat2 is a transmembrane adaptor protein closely related to LAT. It is expressed in various myeloid and lymphoid cells, many of which also express LAT. Phosphorylation of LAB occurs following engagement of various ITAM- and non-ITAM-linked receptors and can play positive and negative roles following receptor engagement. LAT binds PLCγ directly, resulting in efficient Ca²+ flux and degranulation. However, LAB does not contain a PLCγ-binding motif and only binds PLCγ indirectly, possibly via Grb2, thereby resulting in suboptimal signaling. As LAT can signal more efficiently than LAB, competition between the 2 for space/substrates in the lipid rafts can attenuate signaling. This competition model requires coexpression of LAT; however, LAB is repressive, even in cells lacking substantial LAT expression such as macrophages and mature B cells. The reported interaction between LAB and the ubiquitin E3-ligase c-Cbl suggests 1 possible mechanism for LAT-independent inhibition by LAB, but such a model requires further investigation. Given the wide-reaching expression pattern of LAB, LAB has the ability to modulate signaling in virtually every type of leukocyte. Regardless of its ultimate mode of action, the potent regulatory capability of LAB proves this protein to be a complex adaptor that warrants continued, substantial scrutiny by biochemists and immunologists alike.

  7. Search For Dark Matter Satellites Using Fermi-Lat

    DOE PAGES

    Ackermann, M.

    2012-02-23

    Numerical simulations based on the ΛCDM 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 γ-ray emission expected from the annihilation of weakly interacting massive particle (WIMP) dark matter. Some dark matter satellites are expected to have hard γ-ray spectra, finite angular extents, and a lack of counterparts at other wavelengths. We sought to identify LAT sources with these characteristics, focusing on γ-ray spectra consistent with WIMP annihilation through themore » $$b \\bar{b}$$ 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.« less

  8. SPECTRAL ANALYSIS OF FERMI -LAT BLAZARS ABOVE 50 GEV

    DOE PAGES

    Domínguez, Alberto; Ajello, Marco

    2015-11-04

    We present an analysis of the intrinsic (unattenuated by the extragalactic background light, EBL) power-law spectral indices of 128 extragalactic sources detected up to z ~ 2 with the Fermi-Large Area Telescope (LAT) at very high energies (VHEs, E ≥50 GeV). The median of the intrinsic index distribution is 2.20 (versus 2.54 for the observed distribution). We also analyze the observed spectral breaks (i.e., the difference between the VHE and high energy, HE, 100 MeV ≤ E ≤ 300 GeV, spectral indices). The Fermi-LAT has now provided a large sample of sources detected both at VHE and HE with comparablemore » exposure that allows us to test models of extragalactic γ-ray photon propagation. We find that our data are compatible with simulations that include intrinsic blazar curvature and EBL attenuation. There is also no evidence of evolution with redshift of the physics that drives the photon emission in high-frequency synchrotron peak (HSP) blazars. This makes HSP blazars excellent probes of the EBL.« less

  9. Fermi LAT Limits on Primordial Black Hole Evaporation

    NASA Astrophysics Data System (ADS)

    Johnson, Chistian; Malyshev, Dmitry; Funk, Stefan; Ritz, Steven; Fermi LAT Collaboration

    2017-01-01

    Primordial black holes (PBHs) of sufficiently small mass emit gamma rays in the Fermi Large Area Telescope (LAT) energy range. PBHs with lifetimes shorter than the Fermi observation time will appear as moving point sources with gamma-ray emission that becomes harder and brighter with time until the PBH completely evaporates. Previous searches for gamma rays from PBHs have focused on either short time scale bursts or the contribution of PBH bursts to the isotropic diffuse emission. Here we use Fermi LAT point source catalogs to search for PBH candidates that evaporate on a time scale of several years. In addition to looking for the spectral signatures of a PBH, we also develop an algorithm to detect proper motion. There are a few unassociated point sources with spectra consistent with PBH evaporation; however, none of these sources show significant proper motion. We derive a conservative limit on PBH evaporation rate in the vicinity of the Earth by using a threshold on the gamma-ray flux above 10 GeV such that there are no sources above this threshold with spectra consistent with Hawking radiation from PBHs. The derived limit is more stringent than the limits obtained with ground-based gamma-ray observatories.

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

    PubMed Central

    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

    2016-01-01

    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 Ca2+ mobilization, residual T cells were able to induce Ca2+ 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

  11. 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

  12. On-orbit performance of TOPEX/POSIEDON star trackers

    NASA Astrophysics Data System (ADS)

    Kia, Tooraj; Hanover, Gene A.

    1996-10-01

    The primary objective of the TOPEX/POSIEDON satellite is to monitor the world's oceans for scientific study of ocean circulation leading to weather and climate prediction, coastal storm warning and maritime safety. TOPEX/POSIEDON was launched on August 10, 1992 from the Kourou Space Center in French Guyana on a nominal circular orbit with an altitude of 1336 Km with a 66 degree inclination. Selection of this orbit imposed challenging requirements on the on- board electronics. At this altitude, South Atlantic Anomaly (SAA) covers a large area. During many orbits the satellite may spend up to 40 minutes in the SAA region, all the time being bombarded by heavy protons and other charged particles. The on-board electronics were required to endure an estimated total dose radiation of 70 KRAD, with an RDM of 2, over the prime mission life of three years. In addition to the total dose radiation requirement, the spacecraft is required to perform within specifications in-spite of the heavy protons present at this orbit. TOPEX/POSIEDON is the first NASA satellite to carry two CCD based star trackers on a long duration mission. TOPEX/POSIEDON star trackers, known as advanced star tracker (ASTRA), were designed and built by Hughes Danbury Optical Systems (HDOS). These trackers have experienced single-event upsets and possible radiation induced radiation changes in their characteristics. One of the trackers has been in an in-operable state since being hit by a suspected SEU in November 1992. The second tracker has also had anomalies indicative of an SEU, but has managed to recover and is performing within the TOPEX specifications. JPL has been monitoring and evaluating the performance of these star trackers, during the last forty months. The data show change in certain tracker characteristics such as the magnitude of the detected stars, the background counts and the hot pixel data. This paper addresses the CCD tracker performance and the change in their characteristics in the

  13. Forecasting method in multilateration accuracy based on laser tracker measurement

    NASA Astrophysics Data System (ADS)

    Aguado, Sergio; Santolaria, Jorge; Samper, David; José Aguilar, Juan

    2017-02-01

    Multilateration based on a laser tracker (LT) requires the measurement of a set of points from three or more positions. Although the LTs’ angular information is not used, multilateration produces a volume of measurement uncertainty. This paper presents two new coefficients from which to determine whether the measurement of a set of points, before performing the necessary measurements, will improve or worsen the accuracy of the multilateration results, avoiding unnecessary measurement, and reducing the time and economic cost required. The first specific coefficient measurement coefficient (MCLT) is unique for each laser tracker. It determines the relationship between the radial and angular laser tracker measurement noise. Similarly, the second coefficient is related with specific conditions of measurement β. It is related with the spatial angle between the laser tracker positions α and its effect on error reduction. Both parameters MCLT and β are linked in error reduction limits. Beside these, a new methodology to determine the multilateration reduction limit according to the multilateration technique of an ideal laser tracker distribution and a random one are presented. It provides general rules and advice from synthetic tests that are validated through a real test carried out in a coordinate measurement machine.

  14. Exposure time optimization for highly dynamic star trackers.

    PubMed

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

    2014-03-11

    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.

  15. Application Of Expert System Techniques To A Visual Tracker

    NASA Astrophysics Data System (ADS)

    Myler, Harley R.; Thompson, Wiley E.; Flachs, Gerald M.

    1985-04-01

    A structure for visual tracking system is presented which relies on information developed from previous tracking scenarios stored in a knowledge base to enhance tracking performance. The system is comprised of a centroid tracker front end which supplies segmented image features to a data reduction algorithm which holds the reduced data in a temporary data base relation. This relation is then classified vio two separate modes, learn and track. Under learn mode, an external teacher-irector operator provides identification and weighting cues for membership in a long-term storage relation within a knowledge base. Track mode operates autonomously from the learn mode where the system determines feature validity by applying fuzzy set membership criteria to previously stored track information in the database. Results determined from the classification generate tracker directives which either enhance or permit current tracking to continue or cause the tracker to search for alternate targets based upon analysis of a global target tracking list. The classification algorithm is based on correlative analysis of the tracker's segmented output presentation after low pass filtering derives lower order harmonics of the feature. The fuzzy set membership criteria is based on size, rotation, Irame location, and past history of the feature. The first three factors are lin-ear operations on the spectra, while the last is generated as a context relation in the knowledge base. The context relation interlinks data between features to facilitate tracker operation during feature occlusion or presence of countermeasures.

  16. Construction and commissioning of the SuperNEMO detector tracker

    NASA Astrophysics Data System (ADS)

    Cascella, Michele; SuperNEMO Collaboration

    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.

  17. 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

  18. SALT tracker upgrade utilizing aerospace processes and procedures

    NASA Astrophysics Data System (ADS)

    van den Berg, Raoul; Coetzee, Chris; Strydom, Ockert; Brink, Janus; Browne, Keith; Wiid, Eben; Lochner, Wouter; Nelson, Grant; Rabe, Paul; Wilkinson, Martin; Moore, Vic; Malan, Adelaide; Love, Jonathan; Koeslag, Anthony

    2016-08-01

    The SALT Tracker was originally designed to carry a payload of approximately 1000 kg. The current loading exceeds 1300 kg and more instrumentation, for example, the Near-Infrared (NIR) arm of the Robert Stobie Spectrograph (RSS), is being designed for the telescope. In general, provision also had to be made to expand the envelope of the tracker payload carrying capacity for future growth as some of the systems on SALT are currently running with small safety margins. It was therefore decided to upgrade the SALT Tracker to be able to carry a payload of 1875 kg. Before the project "Kick-Off" it became evident that neither SALT nor SAAO had the required standard of formal processes and procedures to execute a project of this nature. The Project Management, Mechanical Design and Review processes and procedures were adopted from the Aerospace Industry and tailored for our application. After training the project team in the application of these processes/procedures and gaining their commitment, the Tracker Upgrade Project was "Kicked-Off" in early May 2013. The application of these aerospace-derived processes and procedures, as used during the Tracker Upgrade Project, were very successful as is shown in this paper where the authors also highlight some of the details of the implemented processes and procedures as well as specific challenges that needed to be met while executing a project of this nature and technical complexity.

  19. 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.

  20. 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.

  1. The Gamma-Ray Large-Area Space Telescope: An Astro-Particle Mission to Explore the High-Energy Gamma-Ray Sky

    SciTech Connect

    Spandre, Gloria; /INFN, Pisa

    2009-05-12

    The Gamma Ray Large Area Space Telescope (GLAST) is a space mission that will detect photons from the gamma ray sky, in the rich yet poorly explored high energy band between 20MeV and 1TeV. Main instrument on board is the Large Area Telescope (LAT), a gamma-ray pair-conversion telescope, that will measure direction and energy of incoming photons by means of a very large (11.000 sensors), low pitch (228 {micro}m) Silicon strip Tracker and an imaging CsI e.m. calorimeter, supported in the rejection of charged particles background by an outer, segmented Anti-Coincidence Detector built with plastic scintillators. The superior angular resolution of the LAT, coupled to its very large field of view, results in a sensitivity advance of a factor 30 or more with respect to previously flown instruments. This will allow GLAST to locate currently unresolved gamma ray sources and to detect potential new classes of sources. Study of the residual gamma ray background will have a crucial role in connection to cosmological models, supersymmetric dark matter and relics of exotic particle decay searches. An accurate spectroscopy of all gamma ray emitters will be possible with the high energy resolution of the calorimeter, improving our knowledge of the mechanisms that power the cores of blazars and AGNs, and enabling tens of different pulsar emission models. The GLAST mission will have the instrumental capabilities to locate and analyze sources of cosmic rays and investigate on their acceleration mechanism. As for transient phenomena studies, like the spectacular GRBs, known to be the most energetic natural events, GLAST is in a prominent position. This is due to the minimum detection dead time (<100 {micro}s), typical of the silicon detectors used for the LAT tracker, and to the increased field of view and alert capabilities of the second GLAST instrument, the Gamma Burst Monitor (GBM), essentially conceived as a fast transients trigger for the more accurate observations from the LAT

  2. 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

  3. The silicon tracker detector of the AMS experiment.

    NASA Astrophysics Data System (ADS)

    Ambrosi, G.

    1999-02-01

    The AMS experiment is devoted to the measurement of the antimatter component of cosmic rays. The experiment is based on a large-acceptance magnetic spectrometer consisting of a precision tracker and time-of-flight counters, mounted on a permanent magnet providing a large bending power. The apparatus will operate in space with a preliminary version flying in May 1998 on the Space Shuttle mission STS91 and a final installation on the International Space Station Alpha (ISSA) in the year 2002. The design of the silicon tracker is described, illustrating features and solutions introduced to make it suitable for a space-borne experiment and for equipping the ≡1 m3 magnet bore. Some of the issues related to the construction of a large, high-precision silicon microstrip tracker are also discussed.

  4. 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.

  5. Context Aware Programmable Trackers for the Next Generation Internet

    NASA Astrophysics Data System (ADS)

    Sousa, Pedro

    This work introduces and proposes the concept of context aware programmable trackers for the next generation Internet. The proposed solution gives ground for the development of advanced applications based on the P2P paradigm and will foster collaborative efforts among several network entities (e.g. P2P applications and ISPs). The proposed concept of context aware programmable trackers allows that several peer selection strategies might be supported by a P2P tracker entity able to improve the peer selection decisions according with pre-defined objectives and external inputs provided by specific services. The flexible, adaptive and enhanced peer selection semantics that might be achieved by the proposed solution will contribute for devising novel P2P based services and business models for the future Internet.

  6. 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.

  7. 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.

  8. Upgrades of the CMS Outer Tracker for HL-LHC

    NASA Astrophysics Data System (ADS)

    Sguazzoni, Giacomo

    2017-02-01

    The LHC machine is planning an upgrade program which will smoothly bring the luminosity to about 5 ×1034cm-2s-1 around 2028, to possibly reach an integrated luminosity of 3000 fb-1 in the following decade. This High Luminosity LHC scenario, HL-LHC, will require a preparation program of the LHC detectors known as Phase-2 upgrade. The current CMS Outer Tracker, already running close to its design limits, will not be able to survive HL-LHC radiation conditions and CMS will need a completely new device, in order to fully exploit the highly demanding operating conditions and the delivered luminosity. The new Tracker should have also L1 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 Outer Tracker upgrades are discussed along with some highlights of the R&D activities.

  9. 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

  10. Laser Tracker Test Facility at SLAC - Progress Report

    SciTech Connect

    Gassner, G.L.; Ruland, R.E.; /SLAC

    2008-02-22

    Physics experiments at SLAC require high accuracy positioning, e. g. 100 {micro}m over a distance of 150 m or 25 {micro}m in a 10 x 10 x 3 meter volume. Laser Tracker measurement systems have become one of the most important tools for achieving these accuracies when mapping components. In order to improve and get a better understanding of laser tracker measurement tolerances we extended our laboratory with a rotary calibration table (Kugler GmbH) providing an accuracy of better than 0.2 arcsec. This paper gives an overview of the calibration table and its evaluation. Results of tests on two of our Laser Trackers utilizing the new rotary table as well as the SLAC interferometer bench are presented.

  11. 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.

  12. 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

  13. Simple electro-optically controlled dual-axis sun tracker

    SciTech Connect

    Lynch, W.A.; Salameh, Z.M. )

    1990-01-01

    This paper describes the design of a sun tracker which uses two electro-optic sensors and a small, low-cost electronic control circuit. One sensor is a four-cell pyramid which is mounted on the tracker plane. The second sensor is a sunlight beam sensor which is fixed facing south. The control circuit tracking resolution is within 0.1 degrees. This system minimizes wandering on partially overcast days. It will never make multiple revolutions or face down towards the ground. Power MOSFETS (Metal Oxide Semiconductor Field Effect Transistors) are used to drive high-torque DC gearbox motors.

  14. Environmental testing results over a tracker drive train

    NASA Astrophysics Data System (ADS)

    Martínez, María; Calvo-Parra, Gustavo; Gil, Eduardo; de la Rubia, Oscar; Hillebrand, Mario; Rubio, Francisca; Aipperspach, Wolfgang; Gombert, Andreas

    2014-09-01

    Environmental testing following the draft of the IEC62817 standard has been carried out at ISFOC using a Soitec Solar tracker drive. The objective of this work is twofold; first to assure that the tracker design can perform under varying conditions and survive under extreme conditions and secondly to test the viability and usefulness of the tests described in the standard. After some changes in the device under test (specifically, gear-box oil) the drive system produced satisfactory results, assuring its performance under operational temperatures. Therefore, this work has demonstrated that the tests described in the standard are useful for detecting early failures.

  15. Detector production for the R3B Si-tracker

    NASA Astrophysics Data System (ADS)

    Borri, M.; Lemmon, R.; Thornhill, J.; Bate, R.; Chartier, M.; Clague, N.; Herzberg, R.-D.; Labiche, M.; Lindsay, S.; Nolan, P.; Pearce, F.; Powell, W.; Wells, D.

    2016-11-01

    R3B is a fixed target experiment which will study reactions with relativistic radioactive beams at FAIR. Its Si-tracker will surround the target volume and it will detect light charged-particles like protons. The detector technology in use consists of double-sided silicon strip sensors wire bonded to the custom made R3B-ASIC. The tracker allows for a maximum of two outer layers and one inner layer. This paper reports on the production of detectors necessary to build the minimum tracking configuration: one inner layer and one outer layer.

  16. Retroreflector field tracker. [noncontact optical position sensor for space application

    NASA Technical Reports Server (NTRS)

    Wargocki, F. E.; Ray, A. J.; Hall, G. E.

    1984-01-01

    An electrooptical position-measuring instrument, the Retroreflector Field Tracker or RFT, is described. It is part of the Dynamic Augmentation Experiment - a part of the payload of Space Shuttle flight 41-D in Summer 1984. The tracker measures and outputs the position of 23 reflective targets placed on a 32-m solar array to provide data for determination of the dynamics of the lightweight structure. The sensor uses a 256 x 256 pixel CID detector; the processor electronics include three Z-80 microprocessors. A pulsed laser diode illuminator is used.

  17. 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.

  18. 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.

  19. Design of a cost-effective laser spot tracker

    NASA Astrophysics Data System (ADS)

    Artan, Göktuǧ Gencehan; Sari, Hüseyin

    2017-05-01

    One of the most important aspects of guided systems is detection. The most convenient detection in the sense of precision can be achieved with a laser spot tracker. This study deals with a military grade, high performance and cost-effective laser spot tracker for a guided system. The aim is to develop a high field of view system that will detect a laser spot from a distance of 3 kilometers in which the target is designated from 3 kilometers with a laser. The study basically consists of the system design, modeling, producing and the conducting performance tests of the whole system.

  20. The straw tube tracker of the P¯ANDA experiment

    NASA Astrophysics Data System (ADS)

    Costanza, S.; Benussi, L.; Braghieri, A.; Boca, G.; Genova, P.; Gianotti, P.; Lavezzi, L.; Lucherini, V.; Montagna, P.; Orecchini, D.; Pierluigi, D.; Ritman, J.; Roeder, M.; Rotondi, A.; Russo, A.; Wintz, P.

    2010-05-01

    P¯ANDA is a new experiment that will be installed at HESR, the new antiproton storage ring under construction as a part of the FAIR facility at Darmstadt, Germany. This experiment, that will investigate QCD in the charmonium mass regime and other aspects of particle and nuclear physics, will be a fixed target detector with a central spectrometer and a forward one. The central tracker will provide information about decay vertices, momenta and types of charged particles emitted after pp¯ annihilations. The design of the Straw Tube Tracker (STT) together with experimental results of the R&D phase are presented here.

  1. 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.

  2. 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.

  3. Production of free glutamate in milk requires the leucine transporter LAT1.

    PubMed

    Matsumoto, Takuya; Nakamura, Eiji; Nakamura, Hidehiro; Hirota, Mariko; San Gabriel, Ana; Nakamura, Ken-Ichiro; Chotechuang, Nattida; Wu, Guoyao; Uneyama, Hisayuki; Torii, Kunio

    2013-09-15

    The concentration of free glutamate (Glu) in rat's milk is ∼10 times higher than that in plasma. Previous work has shown that mammary tissue actively transports circulatory leucine (Leu), which is transaminated to synthesize other amino acids such as Glu and aspartate (Asp). To investigate the molecular basis of Leu transport and its conversion into Glu in the mammary gland, we characterized the expression of Leu transporters and [(3)H]Leu uptake in rat mammary cells. Gene expression analysis indicated that mammary cells express two Leu transporters, LAT1 and LAT2, with LAT1 being more abundant than LAT2. This transport system is sodium independent and transports large neutral amino acids. The Leu transport system in isolated rat mammary cells could be specifically blocked by the LAT1 inhibitors 2-aminobicyclo-[2.2.1]-heptane-2-carboxylic acid (BCH) and triiodothyronine (T3). In organ cultures, Glu secretion was markedly inhibited by these LAT1 inhibitors. Furthermore, the profiles of Leu uptake inhibition by amino acids in mammary cells were similar to those reported for LAT1. In vivo, concentrations of free Glu and Asp increased in milk by oral gavage with Leu at 6, 12, and 18 days of lactation. These results indicate that the main Leu transporter in mammary tissue is LAT1 and the transport of Leu is a limiting factor for the synthesis and release of Glu and Asp into milk. Our studies provide the bases for the molecular mechanism of Leu transport in mammary tissue by LAT1 and its active role on free Glu secretion in milk, which confer umami taste in suckling pups.

  4. Stabilization of a prokaryotic LAT transporter by random mutagenesis.

    PubMed

    Rodríguez-Banqueri, Arturo; Errasti-Murugarren, Ekaitz; Bartoccioni, Paola; Kowalczyk, Lukasz; Perálvarez-Marín, Alex; Palacín, Manuel; Vázquez-Ibar, José Luis

    2016-04-01

    The knowledge of three-dimensional structures at atomic resolution of membrane transport proteins has improved considerably our understanding of their physiological roles and pathological implications. However, most structural biology techniques require an optimal candidate within a protein family for structural determination with (a) reasonable production in heterologous hosts and (b) good stability in detergent micelles. SteT, the Bacillus subtilis L-serine/L-threonine exchanger is the best-known prokaryotic paradigm of the mammalian L-amino acid transporter (LAT) family. Unfortunately, SteT's lousy stability after extracting from the membrane prevents its structural characterization. Here, we have used an approach based on random mutagenesis to engineer stability in SteT. Using a split GFP complementation assay as reporter of protein expression and membrane insertion, we created a library of 70 SteT mutants each containing random replacements of one or two residues situated in the transmembrane domains. Analysis of expression and monodispersity in detergent of this library permitted the identification of evolved versions of SteT with a significant increase in both expression yield and stability in detergent with respect to wild type. In addition, these experiments revealed a correlation between the yield of expression and the stability in detergent micelles. Finally, and based on protein delipidation and relipidation assays together with transport experiments, possible mechanisms of SteT stabilization are discussed. Besides optimizing a member of the LAT family for structural determination, our work proposes a new approach that can be used to optimize any membrane protein of interest. © 2016 Rodríguez-Banqueri et al.

  5. Stabilization of a prokaryotic LAT transporter by random mutagenesis

    PubMed Central

    Rodríguez-Banqueri, Arturo; Errasti-Murugarren, Ekaitz; Bartoccioni, Paola; Kowalczyk, Lukasz; Perálvarez-Marín, Alex

    2016-01-01

    The knowledge of three-dimensional structures at atomic resolution of membrane transport proteins has improved considerably our understanding of their physiological roles and pathological implications. However, most structural biology techniques require an optimal candidate within a protein family for structural determination with (a) reasonable production in heterologous hosts and (b) good stability in detergent micelles. SteT, the Bacillus subtilis l-serine/l-threonine exchanger is the best-known prokaryotic paradigm of the mammalian l–amino acid transporter (LAT) family. Unfortunately, SteT’s lousy stability after extracting from the membrane prevents its structural characterization. Here, we have used an approach based on random mutagenesis to engineer stability in SteT. Using a split GFP complementation assay as reporter of protein expression and membrane insertion, we created a library of 70 SteT mutants each containing random replacements of one or two residues situated in the transmembrane domains. Analysis of expression and monodispersity in detergent of this library permitted the identification of evolved versions of SteT with a significant increase in both expression yield and stability in detergent with respect to wild type. In addition, these experiments revealed a correlation between the yield of expression and the stability in detergent micelles. Finally, and based on protein delipidation and relipidation assays together with transport experiments, possible mechanisms of SteT stabilization are discussed. Besides optimizing a member of the LAT family for structural determination, our work proposes a new approach that can be used to optimize any membrane protein of interest. PMID:26976827

  6. Expanding the Gamma-ray Universe: High Redshift Fermi-LAT Blazars

    NASA Astrophysics Data System (ADS)

    Ojha, Roopesh; Paliya, Vaidehi; Gasparrini, Dario; Ajello, Marco; Cutini, Sara; Fermi-LAT Collaboration

    2017-01-01

    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 Fermi-LAT sample. These blazars appear to host very massive black holes and could shed light on the origin and growth of black holes in the early Universe. We present the latest high redshift blazar detections in the LAT and discuss some of their implications.

  7. A Search for Cosmic-ray Proton Anisotropies with Fermi LAT

    NASA Astrophysics Data System (ADS)

    Meehan, Matthew; Vandenbroucke, Justin; Fermi-LAT Collaboration

    2017-01-01

    In eight years of operation, the Fermi Large Area Telescope (LAT) has detected a large sample of cosmic-ray protons. The LAT's wide field of view and full-sky coverage make it an excellent instrument for studying anisotropies in the arrival directions of protons at all angular scales. These capabilities enable the LAT to make a full-sky 2D measurement of cosmic-ray proton anisotropy complementary to many recent TeV measurements, which are performed by projecting onto right ascension. Any detected anisotropies probe the structure of the local interstellar magnetic field and could indicate the presence of a nearby source

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  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. 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.

  15. 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.

  16. Radiation-hard breadboard star tracker. Final report

    SciTech Connect

    Hubbard, M.W.; Murata, D.L.

    1985-09-01

    Operation in a radiation environment affects the performance of many types of electro-optical sensors. Specifically, noise generated from radiation in the detector and front-end electronics in star trackers can degrade the performance of the sensors. Upsets in the related processing electronics can cause loss of track, data interruptions, and in some cases, failure to recover. Degradation of performance can occur in a natural charged-particle environment and becomes worse in a weapon-enhanced radiation environment. High total dose results in component and, in turn, system failure to operate. The objectives of this program, which was conducted by Ball Aerospace Systems Division (BASD) for the Naval Research Laboratory (NRL), were to develop a tracker that could survive a high total dose and to gain a better understanding of the transient effects of radiation on the star tracker performance. Survivability of the star tracker in a radiation environment, both at the component level and at the system level, is of primary importance.

  17. B-jet tagging using the GEM central tracker

    SciTech Connect

    Brooks, M.L.

    1994-01-01

    The efficiency for tagging b-jets with the full GEM central tracker has been determined using a GEANT simulation to be approximately 35% for b-jets with p{sub T} > 50 GeV/c while the fraction of other quark jets that are misidentified as b-jets is on the order of 1--3%.

  18. 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.

  19. 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…

  20. 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