Title :
Preflight calibration and performance of the astro-E2/HXD-II wide-band all-sky monitor
Author :
Ohno, Masanori ; Fukazawa, Yasushi ; Yamaoka, Kazutaka ; Kokubun, Motohide ; Terada, Yukikatsu ; Kotoku, Jun Ichi ; Okada, Yuu ; Hong, Soojing ; Mori, Masanori ; Tsutsui, Akihito ; Endo, Yasuhiko ; Makishima, Kazuo ; Murakami, Toshio ; Nakazawa, Kazuhiro
Author_Institution :
Dept. of Phys. Sci., Hiroshima Univ.
Abstract :
The hard X-ray detector (HXD-II) onboard Astro-E2 consists of a main detector with energy range 10-600 keV and a BGO active shield detector for background reduction. The shield detector wide-band all-sky monitor (WAM) has been designed not only for background reduction but also for all sky monitoring of gamma-ray bursts (GRB) and bright soft gamma-ray sources. WAM has a large geometrical structure of BGO scintillators for reinforcing its stopping power and has an asymmetric shape for reducing its weight. This particular structure of WAM makes the gamma-ray response very complicated, and thus we need careful calibrations before the launch. We then performed preflight calibrations of WAM as a part of the HXD-II calibrations in 2003-2004. We measured the pulse height spectra and stopping power of each unit counter individually before the HXD-II integration by exposing them to collimated gamma-rays. After integration of the HXD-II detector and installing it to the spacecraft, we measured the same issues as above for WAM by irradiating the gamma-ray source from various directions. Taking into account these experimental results, we constructed the gamma-ray response matrix of WAM using the Geant4 Monte Carlo simulation. The response developed in this work was found to have reproduced the experimental data within 10-20% accuracy
Keywords :
Monte Carlo methods; X-ray detection; calibration; gamma-ray astronomy; gamma-ray bursts; solid scintillation detectors; space vehicles; Astro-E2/HXD-II Wide-Band All-Sky Monitor; BGO active shield detector; BGO scintillators; GRB; Geant4 Monte Carlo simulation; WAM; asymmetric shape; background reduction; bright soft gamma-ray sources; collimated gamma-rays; gamma-ray astronomy detectors; gamma-ray bursts; geometrical structure; hard X-ray detector onboard Astro-E2; preflight calibration; pulse height spectra; spacecraft; stopping power; Calibration; Extraterrestrial measurements; Gamma ray bursts; Gamma ray detection; Gamma ray detectors; Monitoring; Pulse measurements; Wideband; X-ray detection; X-ray detectors; BGO; calibration; gamma-ray astronomy detectors;
Journal_Title :
Nuclear Science, IEEE Transactions on
DOI :
10.1109/TNS.2005.860172