Vibration isolation system for cryocoolers of soft x-ray spectrometer on-board ASTRO-H (Hitomi)

Yoh Takei*, Susumu Yasuda, Kosei Ishimura, Naoko Iwata, Atsushi Okamoto, Yoichi Sato, Mina Ogawa, Makoto Sawada, Taro Kawano, Shingo Obara, Chikara Natsukari, Atsushi Wada, Shinya Yamada, Ryuichi Fujimoto, Motohide Kokubun, Noriko Y. Yamasaki, Hiroyuki Sugita, Kenji Minesugi, Yasuo Nakamura, Kazuhisa MitsudaTadayuki Takahashi, Seiji Yoshida, Shoji Tsunematsu, Kenichi Kanao, Katsuhiro Narasaki, Kiyomi Otsuka, F. Scott Porter, Caroline A. Kilbourne, Meng P. Chiao, Megan E. Eckart, Gary A. Sneiderman, James T. Pontius, Dan McCammon, Paul Wilke, John Basile

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)


The soft x-ray spectrometer (SXS) onboard ASTRO-H (named Hitomi after launch) is a microcalorimeter-type spectrometer, installed in a dewar to be cooled at 50 mK. The energy resolution of the SXS engineering model suffered from microvibration from cryocoolers mounted on the dewar. This is mitigated for the flight model (FM) by introducing vibration isolation systems between the cryocoolers and the dewar. The detector performance of the FM was verified before launch of the spacecraft in both ambient condition and thermal-vacuum condition, showing no detectable degradation in energy resolution. The in-orbit detector spectral performance and cryocooler cooling performance were also consistent with that on ground, indicating that the cryocoolers were not damaged by launch environment. The design and performance of the vibration isolation system along with the mechanism of how the microvibration could degrade the cryogenic detector is shown. Lessons learned from the development to mitigate unexpected issues are also described.

Original languageEnglish
Article number011216
JournalJournal of Astronomical Telescopes, Instruments, and Systems
Issue number1
Publication statusPublished - 2018 Jan 1
Externally publishedYes


  • Hitomi
  • cryocooler
  • microcalorimeter
  • microvibration
  • soft x-ray spectrometer
  • vibration isolation

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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