Performance of the helium dewar and the cryocoolers of the Hitomi soft x-ray spectrometer

Ryuichi Fujimoto, Yoh Takei, Kazuhisa Mitsuda, Noriko Y. Yamasaki, Masahiro Tsujimoto, Shu Koyama, Kumi Ishikawa, Hiroyuki Sugita, Yoichi Sato, Keisuke Shinozaki, Atsushi Okamoto, Shunji Kitamoto, Akio Hoshino, Kosuke Sato, Yuichiro Ezoe, Yoshitaka Ishisaki, Shinya Yamada, Hiromi Seta, Takaya Ohashi, Toru TamagawaHirofumi Noda, Makoto Sawada, Makoto Tashiro, Yoichi Yatsu, Ikuyuki Mitsuishi, Kenichi Kanao, Seiji Yoshida, Mikio Miyaoka, Shoji Tsunematsu, Kiyomi Otsuka, Katsuhiro Narasaki, Michael J. DiPirro, Peter J. Shirron, Gary A. Sneiderman, Caroline A. Kilbourne, Frederick Scott Porter, Meng P. Chiao, Megan E. Eckart

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

The soft x-ray spectrometer (SXS) was a cryogenic high-resolution x-ray spectrometer onboard the Hitomi (ASTRO-H) satellite that achieved energy resolution of 5 eV at 6 keV, by operating the detector array at 50 mK using an adiabatic demagnetization refrigerator (ADR). The cooling chain from room temperature to the ADR heat sink was composed of two-stage Stirling cryocoolers, a 4He Joule-Thomson cryocooler, and superfluid liquid helium and was installed in a dewar. It was designed to achieve a helium lifetime of more than 3 years with a minimum of 30 L. The satellite was launched on February 17, 2016, and the SXS worked perfectly in orbit, until March 26 when the satellite lost its function. It was demonstrated that the heat load on the helium tank was about 0.7 mW, which would have satisfied the lifetime requirement. This paper describes the design, results of ground performance tests, prelaunch operations, and initial operation and performance in orbit of the flight dewar and the cryocoolers.

Original languageEnglish
Article number011208
JournalJournal of Astronomical Telescopes, Instruments, and Systems
Volume4
Issue number1
DOIs
Publication statusPublished - 2018 Jan 1

Keywords

  • Hitomi
  • Joule-Thomson cryocooler
  • Stirling cryocooler
  • space cryogenics
  • superfluid liquid helium
  • x-ray microcalorimeter

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Control and Systems Engineering
  • Instrumentation
  • Astronomy and Astrophysics
  • Mechanical Engineering
  • Space and Planetary Science

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    Fujimoto, R., Takei, Y., Mitsuda, K., Yamasaki, N. Y., Tsujimoto, M., Koyama, S., Ishikawa, K., Sugita, H., Sato, Y., Shinozaki, K., Okamoto, A., Kitamoto, S., Hoshino, A., Sato, K., Ezoe, Y., Ishisaki, Y., Yamada, S., Seta, H., Ohashi, T., ... Eckart, M. E. (2018). Performance of the helium dewar and the cryocoolers of the Hitomi soft x-ray spectrometer. Journal of Astronomical Telescopes, Instruments, and Systems, 4(1), [011208]. https://doi.org/10.1117/1.JATIS.4.1.011208