TY - JOUR
T1 - Hard x-ray imager onboard Hitomi (ASTRO-H)
AU - Nakazawa, Kazuhiro
AU - Sato, Goro
AU - Kokubun, Motohide
AU - Enoto, Teruaki
AU - Fukazawa, Yasushi
AU - Hagino, Kouichi
AU - Hayashi, Katsuhiro
AU - Kataoka, Jun
AU - Katsuta, Junichiro
AU - Kobayashi, Shogo B.
AU - Laurent, Philippe
AU - Lebrun, Francois
AU - Limousin, Olivier
AU - Maier, Daniel
AU - Makishima, Kazuo
AU - Mizuno, Tsunefumi
AU - Mori, Kunishiro
AU - Nakamori, Takeshi
AU - Nakano, Toshio
AU - Noda, Hirofumi
AU - Odaka, Hirokazu
AU - Ohno, Masanori
AU - Ohta, Masayuki
AU - Saito, Shinya
AU - Sato, Rie
AU - Tajima, Hiroyasu
AU - Takahashi, Hiromitsu
AU - Takahashi, Tadayuki
AU - Takeda, Shin'ichiro
AU - Tanaka, Takaaki
AU - Terada, Yukikatsu
AU - Uchiyama, Hideki
AU - Uchiyama, Asunobu
AU - Watanabe, Shin
AU - Yamaoka, Kazutaka
AU - Yatsu, Yoichi
AU - Yuasa, Takayuki
N1 - Funding Information:
We are grateful to the whole Hitomi team; the hardware teams, the software team, as well as the operation team and the science team, for all their effort to realize the great but sadly short-lived satellite. The HXI system owes a lot to Mitsubishi Heavy Industries in its manufacturing, as well. We also note that this instrument is supported by dedicated works of many graduate and some undergraduate students from universities and research institutes in Japan and France. We acknowledge support from JSPS/MEXT KAKENHI grant numbers 24105007, 15H03639, 25287059, 24244014, and the JSPS Core-to-Core Program. All U.S. members acknowledge support through the NASA Science Mission Directorate. Stanford and SLAC members acknowledge support via DoE contract to SLAC National Accelerator Laboratory DE-AC3-76SF00515 and NASA grant NNX15AM19G. The BGO crystal and HV bias suppliers are supported from ESA. French members acknowledge support from CNES, the Centre National dEtudes Spatiales. We thank contributions by many other companies, such as NEC, Hamamatsu Photonics, Acrorad, OKEN, Ideas, and SUPER RESIN.
PY - 2018/4/1
Y1 - 2018/4/1
N2 - The hard x-ray imaging spectroscopy system of "Hitomi" x-ray observatory is composed of two sets of hard x-ray imagers (HXI) coupled with hard x-ray telescopes (HXT). With a 12-m focal length, the system provides fine (10:7 half-power diameter) imaging spectroscopy covering about 5 to 80 keV. The HXI sensor consists of a camera, which is composed of four layers of Si and one layer of CdTe semiconductor imagers, and an active shield composed of nine Bi4Ge3O12 scintillators to provide low background. The two HXIs started observation on March 8 and 14, 2016 and were operational until 26 March. Using a Crab observation, 5 to 80 keV energy coverage and good detection efficiency were confirmed. The detector background level of 1 to 3 × 10-4 counts s?1 keV?1 cm?2 (in detector geometrical area) at 5 to 80 keV was achieved, by cutting the high-background time-intervals, adopting sophisticated energy-dependent imager layer selection, and baffling of the cosmic x-ray background and active-shielding. This level is among the lowest of detectors working in this energy band. By comparing the effective area and the background, it was shown that the HXI had a sensitivity that is same to that of NuSTAR for point sources and 3 to 4 times better for largely extended diffuse sources.
AB - The hard x-ray imaging spectroscopy system of "Hitomi" x-ray observatory is composed of two sets of hard x-ray imagers (HXI) coupled with hard x-ray telescopes (HXT). With a 12-m focal length, the system provides fine (10:7 half-power diameter) imaging spectroscopy covering about 5 to 80 keV. The HXI sensor consists of a camera, which is composed of four layers of Si and one layer of CdTe semiconductor imagers, and an active shield composed of nine Bi4Ge3O12 scintillators to provide low background. The two HXIs started observation on March 8 and 14, 2016 and were operational until 26 March. Using a Crab observation, 5 to 80 keV energy coverage and good detection efficiency were confirmed. The detector background level of 1 to 3 × 10-4 counts s?1 keV?1 cm?2 (in detector geometrical area) at 5 to 80 keV was achieved, by cutting the high-background time-intervals, adopting sophisticated energy-dependent imager layer selection, and baffling of the cosmic x-ray background and active-shielding. This level is among the lowest of detectors working in this energy band. By comparing the effective area and the background, it was shown that the HXI had a sensitivity that is same to that of NuSTAR for point sources and 3 to 4 times better for largely extended diffuse sources.
KW - astronomy.
KW - detectors
KW - gamma rays
KW - satellites
KW - x-rays
UR - http://www.scopus.com/inward/record.url?scp=85044840591&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85044840591&partnerID=8YFLogxK
U2 - 10.1117/1.JATIS.4.2.021410
DO - 10.1117/1.JATIS.4.2.021410
M3 - Article
AN - SCOPUS:85044840591
VL - 4
JO - Journal of Astronomical Telescopes, Instruments, and Systems
JF - Journal of Astronomical Telescopes, Instruments, and Systems
SN - 2329-4124
IS - 2
M1 - 21410
ER -