Cryogen-free operation of the Soft X-ray Spectrometer instrument

Gary A. Sneiderman, Peter J. Shirron, Ryuichi Fujimoto, Thomas G. Bialas, Kevin R. Boyce, Meng P. Chiao, Michael J. DiPirro, Megan E. Eckart, Leslie Hartz, Yoshitaka Ishisaki, Richard L. Kelley, Caroline A. Kilbourne, Candace Masters, Dan McCammon, Kazuhisa Mitsuda, Hirofumi Noda, Frederick S. Porter, Andrew E. Szymkowiak, Yoh Takei, Masahiro TsujimotoSeiji Yoshida

Research output: Chapter in Book/Report/Conference proceedingConference contribution

14 Citations (Scopus)


The Soft X-ray Spectrometer (SXS) is the first space-based instrument to implement redundancy in the operation of a sub-Kelvin refrigerator. The SXS cryogenic system consists of a superfluid helium tank and a combination of Stirling and Joule-Thompson (JT) cryocoolers that support the operation of a 3-stage adiabatic demagnetization refrigerator (ADR). When liquid helium is present, the x-ray microcalorimeter detectors are cooled to their 50 mK operating temperature by two ADR stages, which reject their heat directly to the liquid at ∼1.1 K. When the helium is depleted, all three ADR stages are used to accomplish detector cooling while rejecting heat to the JT cooler operating at 4.5 K. Compared to the simpler helium mode operation, the cryogen-free mode achieves the same instrument performance by controlling the active cooling devices within the cooling system differently. These include the three ADR stages and four active heat switches, provided by NASA, and five cryocoolers, provided by JAXA. Development and verification details of this capability are presented within this paper and offer valuable insights into the challenges, successes, and lessons that can benefit other missions, particularly those employing cryogen-free cooling systems.

Original languageEnglish
Title of host publicationSpace Telescopes and Instrumentation 2016
Subtitle of host publicationUltraviolet to Gamma Ray
EditorsMarshall Bautz, Tadayuki Takahashi, Jan-Willem A. den Herder
ISBN (Electronic)9781510601895
Publication statusPublished - 2016
EventSpace Telescopes and Instrumentation 2016: Ultraviolet to Gamma Ray - Edinburgh, United Kingdom
Duration: 2016 Jun 262016 Jul 1

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherSpace Telescopes and Instrumentation 2016: Ultraviolet to Gamma Ray
Country/TerritoryUnited Kingdom


  • ADR
  • Astro-H
  • SXS
  • cooling system
  • cryocooler
  • cryogen-free
  • cryogenic
  • refrigeration

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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