@inproceedings{c714cfdb880e4b13b1d8ab1c4e739b4d,
title = "Cryogen-free operation of the Soft X-ray Spectrometer instrument",
abstract = "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.",
keywords = "ADR, Astro-H, SXS, cooling system, cryocooler, cryogen-free, cryogenic, refrigeration",
author = "Sneiderman, {Gary A.} and Shirron, {Peter J.} and Ryuichi Fujimoto and Bialas, {Thomas G.} and Boyce, {Kevin R.} and Chiao, {Meng P.} and DiPirro, {Michael J.} and Eckart, {Megan E.} and Leslie Hartz and Yoshitaka Ishisaki and Kelley, {Richard L.} and Kilbourne, {Caroline A.} and Candace Masters and Dan McCammon and Kazuhisa Mitsuda and Hirofumi Noda and Porter, {Frederick S.} and Szymkowiak, {Andrew E.} and Yoh Takei and Masahiro Tsujimoto and Seiji Yoshida",
year = "2016",
month = jan,
day = "1",
doi = "10.1117/12.2232045",
language = "English",
series = "Proceedings of SPIE - The International Society for Optical Engineering",
publisher = "SPIE",
editor = "Marshall Bautz and Tadayuki Takahashi and {den Herder}, {Jan-Willem A.}",
booktitle = "Space Telescopes and Instrumentation 2016",
note = "Space Telescopes and Instrumentation 2016: Ultraviolet to Gamma Ray ; Conference date: 26-06-2016 Through 01-07-2016",
}