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Full-Text Articles in Physical Sciences and Mathematics
Hard X-Ray Polarimeter For Gamma-Ray Bursts And Solar Flares, Mark L. Mcconnell, J Ledoux, John R. Macri, James M. Ryan
Hard X-Ray Polarimeter For Gamma-Ray Bursts And Solar Flares, Mark L. Mcconnell, J Ledoux, John R. Macri, James M. Ryan
Space Science Center
We report on the development of a dedicated polarimeter design that is capable of studying the linear polarization of hard X-rays (50-300 keV) from gamma-ray bursts and solar flares. This compact design, based on the use of a large area position-sensitive PMT (PSPMT), is referred to as GRAPE (Gamma-RAy Polarimeter Experiment). The PSPMT is used to determine the Compton interaction location within an array of small plastic scintillator elements. Some of the photons that scatter within the plastic scintillator array are subsequently absorbed by a small centrally-located array of CsI(Tl) crystals that is read out by an independent multi-anode PMT. …
Development Of Czt Strip Detector Modules For 0.05- To 1-Mev Gamma-Ray Imaging And Spectroscopy, James M. Ryan, B Donmez, John R. Macri, M Mcclish, Mark L. Mcconnell, R S. Miller, Mark Widholm, L A. Hamel, Manuel Julien
Development Of Czt Strip Detector Modules For 0.05- To 1-Mev Gamma-Ray Imaging And Spectroscopy, James M. Ryan, B Donmez, John R. Macri, M Mcclish, Mark L. Mcconnell, R S. Miller, Mark Widholm, L A. Hamel, Manuel Julien
Space Science Center
We report progress in our study of cadmium zinc telluride (CZT) strip detectors featuring orthogonal coplanar anode contacts. We specifically report on the performance, characterization and stability of 5 and 10 mm thick prototype CZT detectors fabricated using material from several manufacturers. Our ongoing work includes laboratory and simulation studies aimed at optimizing and developing compact, efficient, high performance detector modules for 0.05 to 1 MeV gamma radiation measurements with space-based instrumentation. The coplanar anode strip configuration retains many of the performance advantages of pixel detectors yet requires far fewer electronic channels to perform both 3-d imaging and spectroscopy. Minimizing …
Nonsolar Astronomy With The Reuven Ramaty High Energy Solar Spectroscopic Imager (Rhessi), David M. Smith, Robert P. Lin, K Hurley, Wayne Coburn, G J. Hurford, Claudia Wigger, W Hajdas, Alex Zehnder, Mark L. Mcconnell
Nonsolar Astronomy With The Reuven Ramaty High Energy Solar Spectroscopic Imager (Rhessi), David M. Smith, Robert P. Lin, K Hurley, Wayne Coburn, G J. Hurford, Claudia Wigger, W Hajdas, Alex Zehnder, Mark L. Mcconnell
Space Science Center
The Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) is a NASA Small Explorer satellite designed to study hard x-ray and gamma-ray emission from solar flares. In addition, its high-resolution array of germanium detectors can see photons from high-energy sources throughout the Universe. Here we discuss the various algorithms necessary to extract spectra, lightcurves, and other information about cosmic gamma-ray bursts, pulsars, and other astrophysical phenomena using an unpointed, spinning array of detectors. We show some preliminary results and discuss our plans for future analyses. All RHESSI data are public, and scientists interested in participating should contact the principal author.
Hard X-Ray Polarimetry With The Ramaty High Energy Solar Spectroscopic Imager (Rhessi), Mark L. Mcconnell, David M. Smith, A G. Emslie, Robert P. Lin, James M. Ryan
Hard X-Ray Polarimetry With The Ramaty High Energy Solar Spectroscopic Imager (Rhessi), Mark L. Mcconnell, David M. Smith, A G. Emslie, Robert P. Lin, James M. Ryan
Space Science Center
Although designed primarily as a hard X-ray imager and spectrometer, the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) is also capable of measuring the polarization of hard X-rays (20-100 keV) from solar flares. This capability arises from the inclusion of a small unobstructed Be scattering element that is strategically located within the cryostat that houses the array of nine germanium detectors. The Ge detectors are segmented, with both a front and rear active volume. Low energy photons (below about 100 keV) can reach a rear segment of a Ge detector only indirectly, by scattering. Low energy photons from the Sun …
Sontrac: An Imaging Spectrometer For Solar Neutrons, James M. Ryan, L Desorgher, E O. Fluckiger, John R. Macri, Mark L. Mcconnell, R S. Miller
Sontrac: An Imaging Spectrometer For Solar Neutrons, James M. Ryan, L Desorgher, E O. Fluckiger, John R. Macri, Mark L. Mcconnell, R S. Miller
Space Science Center
An instrument capable of unambiguously determining the energy and direction of incident neutrons has important applications in solar physics-as well as environmental monitoring and medical/radiological sciences. The SONTRAC (SOlar Neutron TRACking) instrument is designed to operate in the neutron energy range of 20-250 MeV. The measurement principle is based on non-relativistic double scatter of neutrons off ambient protons (n-p scattering) within a block of densely packed scintillating fibers. Using this double-scatter mode it is possible to uniquely determine neutron energy and direction on an event-by-event basis. A fully operational science model of such an instrument has been built using 300 …
The Development Of Grape, A Gamma Ray Polarimeter Experiment, Mark L. Mcconnell, J Ledoux, John R. Macri, James M. Ryan
The Development Of Grape, A Gamma Ray Polarimeter Experiment, Mark L. Mcconnell, J Ledoux, John R. Macri, James M. Ryan
Space Science Center
The measurement of hard X‐ray polarization in γ‐ray bursts (GRBs) would add yet another piece of information in our effort to resolve the true nature of these enigmatic objects. Here we report on the development of a dedicated polarimeter design with a relatively large FoV that is capable of studying hard X‐ray polarization (50–300 keV) from GRBs. This compact design, based on the use of a large area position‐sensitive PMT (PSPMT), is referred to as GRAPE (Gamma‐RAy Polarimeter Experiment). The feature of GRAPE that is especially attractive for studies of GRBs is the significant off‐axis polarization response (at angles greater …