Soft X-ray Imager of the Xtend system on board XRISM

Abstract The Soft X-ray Imager (SXI) is the X-ray charge-coupled device (CCD) camera for the soft X-ray imaging telescope Xtend installed on the X-ray Imaging and Spectroscopy Mission (XRISM), which was adopted as a recovery mission for the Hitomi X-ray satellite and was successfully launched on 2023 September 7 (JST). In order to maximize the science output of XRISM, we set the requirements for Xtend and found that the CCD set employed in the Hitomi/SXI or similar, i.e., a $2 \times 2$ array of back-illuminated CCDs with a $200\, \mu$m-thick depletion layer, would be practically best among the available choices, when used in combination with the X-ray mirror assembly. We designed the XRISM/SXI, based on the Hitomi/SXI, to have a wide field of view of $38^{\prime } \times 38^{\prime }$ in the 0.4–13 keV energy range. We incorporated several significant improvements from the Hitomi/SXI into the CCD chip design to enhance the optical-light blocking capability and to increase the cosmic-ray tolerance, reducing the degradation of charge-transfer efficiency in orbit. By the time of the launch of XRISM, the imaging and spectroscopic capabilities of the SXI had been extensively studied in on-ground experiments with the full flight-model configuration or equivalent setups and confirmed to meet the requirements. The optical blocking capability, the cooling and temperature control performance, and the transmissivity and quantum efficiency to incident X-rays of the CCDs were also all confirmed to meet the requirements. Thus, we successfully completed the pre-flight development of the SXI for XRISM.

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Journal
Publications of the Astronomical Society of Japan
Published
2025-03-11
DOI
https://doi.org/10.1093/pasj/psaf011
Citations
15
Primary Topic
Astrophysical Phenomena and Observations
Type
article
Field-Weighted Citation Impact
17.32

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article

Soft X-ray Imager of the Xtend system on board XRISM

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Publications of the Astronomical Society of Japan
Astrophysical Phenomena and Observations
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article

Soft X-ray Imager of the Xtend system on board XRISM

Hiroshi Nakajima, T. Sako, Kouichi Hagino, Hirokazu Odaka, Yoh Asahina, Hideki Uchiyama, Hirofumi Noda, Shun Tsunomachi, Yoshiaki Kanemaru, Keitaro Miyazaki, Haruhiko Yokosu, Wakana Yonemaru, Kohei K. Shima, Masanori Ozaki, Hiroyuki Uchida, Hironori Matsumoto, Marina Yoshimoto, Katsumi Hayakawa, Shōgo Kobayashi, K. Yamaoka, Toshiyuki Takaki, Yuta Terada, Yuma Aoki, Hiromasa Suzuki, Junko S. Hiraga, Kohei Kusunoki, Takaaki Tanaka, Daiki Aoki, M. Yamauchi, Takeshi Go Tsuru, Masahiro Fukuda, Isamu Hatsukade, Hiroshi Murakami, Kumiko Nobukawa, Shun Inoue, Ken‐ichi Takayama, Yamato Ito, Masayoshi Nobukawa, T. Yoneyama, Tsukasa Matsushima, Yoshinori Otsuka, Yuki Amano, Hanako Nakano, Tessei Yoshida, Koji Mori, Kaito Ninoyu, H. Tsunemi, Hiroshi Tomida, Mayu Higuchi, Takayoshi Kohmura, Takamitsu Kamei, Kiyoshi Hayashida, Jin Sato, Tadayasu Dotani, Kazuhiro Ichikawa, Reo Takemoto, Reika Urase, Jun Kurashima, Kotomi Fuchi, Tomoya Kamatani
article en
15 citations

Abstract

Abstract The Soft X-ray Imager (SXI) is the X-ray charge-coupled device (CCD) camera for the soft X-ray imaging telescope Xtend installed on the X-ray Imaging and Spectroscopy Mission (XRISM), which was adopted as a recovery mission for the Hitomi X-ray satellite and was successfully launched on 2023 September 7 (JST). In order to maximize the science output of XRISM, we set the requirements for Xtend and found that the CCD set employed in the Hitomi/SXI or similar, i.e., a $2 \times 2$ array of back-illuminated CCDs with a $200\, \mu$m-thick depletion layer, would be practically best among the available choices, when used in combination with the X-ray mirror assembly. We designed the XRISM/SXI, based on the Hitomi/SXI, to have a wide field of view of $38^{\prime } \times 38^{\prime }$ in the 0.4–13 keV energy range. We incorporated several significant improvements from the Hitomi/SXI into the CCD chip design to enhance the optical-light blocking capability and to increase the cosmic-ray tolerance, reducing the degradation of charge-transfer efficiency in orbit. By the time of the launch of XRISM, the imaging and spectroscopic capabilities of the SXI had been extensively studied in on-ground experiments with the full flight-model configuration or equivalent setups and confirmed to meet the requirements. The optical blocking capability, the cooling and temperature control performance, and the transmissivity and quantum efficiency to incident X-rays of the CCDs were also all confirmed to meet the requirements. Thus, we successfully completed the pre-flight development of the SXI for XRISM.

Publications of the Astronomical Society of JapanVol. 77(Supplement_1)
University of Miyazaki (JP), Shizuoka University (JP), Nara University of Education (JP), Konan University (JP), Tokyo University of Science (JP), Tohoku University (JP), Kanto Gakuin University (JP), Kwansei Gakuin University (JP), Kyoto University (JP), Czech Academy of Sciences, Astronomical Institute (CZ), Japan Aerospace Exploration Agency (JP), Tohoku Gakuin University (JP), Institute of Space and Astronautical Science (JP), National Astronomical Observatory of Japan (JP), Nagoya University (JP), The University of Tokyo (JP), Kindai University (JP), Chuo University (JP), The University of Osaka (JP)
Japan Society for the Promotion of Science
Openalex Percentile: Top 1%
Astrophysical Phenomena and Observations
17.32
DOIOpen Access PDFOpenAlex
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