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Articles 1 - 6 of 6
Full-Text Articles in Physical Sciences and Mathematics
Advanced Characterization And Simulation Of Sonne: A Fast Neutron Spectrometer For Solar Probe Plus, R S. Woolf, James M. Ryan, Peter F. Bloser, U Bravar, E O. Fluckiger, Jason S. Legere, A L. Mackinnon, Procheta Mallik, Mark L. Mcconnell, B Pirard
Advanced Characterization And Simulation Of Sonne: A Fast Neutron Spectrometer For Solar Probe Plus, R S. Woolf, James M. Ryan, Peter F. Bloser, U Bravar, E O. Fluckiger, Jason S. Legere, A L. Mackinnon, Procheta Mallik, Mark L. Mcconnell, B Pirard
Space Science Center
SONNE, the SOlar NeutroN Experiment proposed for Solar Probe Plus, is designed to measure solar neutrons from 1-20 MeV and solar gammas from 0.5-10 MeV. SONNE is a double scatter instrument that employs imaging to maximize its signal-to-noise ratio by rejecting neutral particles from non-solar directions. Under the assumption of quiescent or episodic small-flare activity, one can constrain the energy content and power dissipation by fast ions in the low corona. Although the spectrum of protons and ions produced by nanoflaring activity is unknown, we estimate the signal in neutrons and γ−rays that would be present within thirty solar radii, …
Grape: A Balloon-Borne Gamma-Ray Polarimeter, Mark L. Mcconnell, Chris Bancroft, Peter F. Bloser, Taylor Connor, Jason S. Legere, James M. Ryan
Grape: A Balloon-Borne Gamma-Ray Polarimeter, Mark L. Mcconnell, Chris Bancroft, Peter F. Bloser, Taylor Connor, Jason S. Legere, James M. Ryan
Space Science Center
The Gamma-RAy Polarimeter Experiment (GRAPE) is a concept for an astronomical hard X-ray Compton polarimeter operating in the 50 - 500 keV energy band. The instrument has been optimized for wide-field polarization measurements of transient outbursts from energetic astrophysical objects such as gamma-ray bursts and solar flares. The GRAPE instrument is composed of identical modules, each of which consists of an array of scintillator elements read out by a multi-anode photomultiplier tube (MAPMT). Incident photons Compton scatter in plastic scintillator elements and are subsequently absorbed in inorganic scintillator elements; a net polarization signal is revealed by a characteristic asymmetry in …
A New Low-Background Compton Telescope Using Labr3 Scintillator, Peter F. Bloser, James M. Ryan, Jason S. Legere, Manuel Julien, Chris Bancroft, Mark L. Mcconnell, Mark Wallace, R M. Kippen, Shawn Tornga
A New Low-Background Compton Telescope Using Labr3 Scintillator, Peter F. Bloser, James M. Ryan, Jason S. Legere, Manuel Julien, Chris Bancroft, Mark L. Mcconnell, Mark Wallace, R M. Kippen, Shawn Tornga
Space Science Center
Gamma-ray astronomy in the MeV range suffers from weak fluxes from sources and high background in the nuclear energy range. The background comes primarily from neutron-induced gamma rays, with the neutrons being produced by cosmic-ray interactions in the Earth's atmosphere, the spacecraft, and the instrument. Compton telescope designs often suppress this background by requiring coincidences in multiple detectors and a narrow time-of-flight (ToF) acceptance window. The COMPTEL experience on the Compton Gamma Ray Observatory shows that a 1.9-ns ToF resolution is insufficiently narrow to achieve the required low background count rate. Furthermore, neutron interactions in the detectors themselves generate an …
A Compton Telescope For Remote Location And Identification Of Radioactive Material, Peter F. Bloser, Jason S. Legere, Shirley M. Dame, Mark L. Mcconnell, U Bravar, James M. Ryan
A Compton Telescope For Remote Location And Identification Of Radioactive Material, Peter F. Bloser, Jason S. Legere, Shirley M. Dame, Mark L. Mcconnell, U Bravar, James M. Ryan
Space Science Center
The spare detectors from NASA's Compton Gamma-Ray Observatory COMPTEL instrument have been reconfigured to demonstrate the capability at ground level to remotely locate and identify sources of gamma radiation. The gamma-ray experimental telescope assembly (GRETA) employs two 28 cm diameter scintillation detectors separated by 95 cm: one 8.5 cm thick liquid scintillator detector and one 7.5 cm thick NaI(Tl) detector. The assembly electronics and real-time data acquisition system measures the energy deposits and time-of-flight for each coincident detection and compiles histograms of total energy and incident angle as computed using the kinematics of Compton scattering. GRETA's field of view is …
Statistical Properties Of Gamma‐Ray Burst Polarization, Kenji Toma, Takanori Sakamoto, Bing Zhang, J E. Hill, Mark L. Mcconnell, Peter F. Bloser, Ryo Yamazaki, Kunihito Ioka, Takashi Nakamura
Statistical Properties Of Gamma‐Ray Burst Polarization, Kenji Toma, Takanori Sakamoto, Bing Zhang, J E. Hill, Mark L. Mcconnell, Peter F. Bloser, Ryo Yamazaki, Kunihito Ioka, Takashi Nakamura
Space Science Center
The emission mechanism and the origin and structure of magnetic fields in gamma‐ray burst (GRB) jets are among the most important open questions concerning the nature of the central engine of GRBs. In spite of extensive observational efforts, these questions remain to be answered and are difficult or even impossible to infer with the spectral and lightcurve information currently collected. Polarization measurements will lead to unambiguous answers to several of these questions. Recent developments in X‐ray and γ‐ray polarimetry techniques have demonstrated a significant increase in sensitivity enabling several new mission concepts, e.g. POET (Polarimeters for Energetic Transients), providing wide …
Grb Polarimetry With Poet, Mark L. Mcconnell, L Angelini, Matthew Baring, Scott Barthelmy, J Kevin Black, Peter F. Bloser, B Dennis, A G. Emslie, J Greiner, W Hajdas, A K. Harding, H Hartmann, J E. Hill, Kunihito Ioka, Philip Kaaret, G Kanbach, D Kniffen, Jason S. Legere, John R. Macri, R Morris, Takashi Nakamura, N Produit, James M. Ryan, Takanori Sakamoto, Kenji Toma, X Wu, Ryo Yamazaki, Bing Zhang
Grb Polarimetry With Poet, Mark L. Mcconnell, L Angelini, Matthew Baring, Scott Barthelmy, J Kevin Black, Peter F. Bloser, B Dennis, A G. Emslie, J Greiner, W Hajdas, A K. Harding, H Hartmann, J E. Hill, Kunihito Ioka, Philip Kaaret, G Kanbach, D Kniffen, Jason S. Legere, John R. Macri, R Morris, Takashi Nakamura, N Produit, James M. Ryan, Takanori Sakamoto, Kenji Toma, X Wu, Ryo Yamazaki, Bing Zhang
Space Science Center
POET (Polarimeters for Energetic Transients) represents a concept for a Small Explorer (SMEX) satellite mission, whose principal scientific goal is to understand the structure of GRB sources through sensitive X‐ray and γ‐ray polarization measurements. The payload consists of two wide field‐of‐view (FoV) instruments: a Low Energy Polarimeter (LEP) capable of polarization measurements in the energy range from 2–15 keV and a high energy polarimeter (Gamma‐Ray Polarimeter Experiment or GRAPE) that would measure polarization in the 60–500 keV energy range. The POET spacecraft provides a zenith‐pointed platform for maximizing the exposure to deep space. Spacecraft rotation provides a means of effectively …