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9 April 2018 Hard x-ray imager onboard Hitomi (ASTRO-H)
Kazuhiro Nakazawa, Goro Sato, Motohide Kokubun, Teruaki Enoto, Yasushi Fukazawa, Kouichi Hagino, Katsuhiro Hayashi, Jun Kataoka, Junichiro Katsuta, Shogo B. Kobayashi, Philippe Laurent, François Lebrun, Olivier Limousin, Daniel Maier, Kazuo Makishima, Tsunefumi Mizuno, Kunishiro Mori, Takeshi Nakamori, Toshio Nakano, Hirofumi Noda, Hirokazu Odaka, Masanori Ohno, Masayuki Ohta, Shinya Saito, Rie Sato, Hiroyasu Tajima, Hiromitsu Takahashi, Tadayuki Takahashi, Shin’ichiro Takeda, Takaaki Tanaka, Yukikatsu Terada, Hideki Uchiyama, Yasunobu Uchiyama, Shin Watanabe, Kazutaka Yamaoka, Yoichi Yatsu, Takayuki Yuasa
Author Affiliations +
Abstract
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 (1  ′    .  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.
CC BY: © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.
Kazuhiro Nakazawa, Goro Sato, Motohide Kokubun, Teruaki Enoto, Yasushi Fukazawa, Kouichi Hagino, Katsuhiro Hayashi, Jun Kataoka, Junichiro Katsuta, Shogo B. Kobayashi, Philippe Laurent, François Lebrun, Olivier Limousin, Daniel Maier, Kazuo Makishima, Tsunefumi Mizuno, Kunishiro Mori, Takeshi Nakamori, Toshio Nakano, Hirofumi Noda, Hirokazu Odaka, Masanori Ohno, Masayuki Ohta, Shinya Saito, Rie Sato, Hiroyasu Tajima, Hiromitsu Takahashi, Tadayuki Takahashi, Shin’ichiro Takeda, Takaaki Tanaka, Yukikatsu Terada, Hideki Uchiyama, Yasunobu Uchiyama, Shin Watanabe, Kazutaka Yamaoka, Yoichi Yatsu, and Takayuki Yuasa "Hard x-ray imager onboard Hitomi (ASTRO-H)," Journal of Astronomical Telescopes, Instruments, and Systems 4(2), 021410 (9 April 2018). https://doi.org/10.1117/1.JATIS.4.2.021410
Received: 7 August 2017; Accepted: 9 March 2018; Published: 9 April 2018
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CITATIONS
Cited by 31 scholarly publications.
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KEYWORDS
Imaging systems

Avalanche photodetectors

Hard x-rays

Satellites

Sensors

Cameras

X-rays


CHORUS Article. This article was made freely available starting 09 April 2019

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