Lifetime test of the 4K Joule-Thomson cryocooler

• Published in: Cryogenics (Guildford) Vol. 116; p. 103306
• Main Authors: Sato, Yoichi, Tanaka, Kosuke, Sugita, Hiroyuki, Shinozaki, Keisuke, Sawada, Kenichiro, Yamasaki, Noriko Y., Nakagawa, Takao, Mitsuda, Kazuhisa, Tsunematsu, Shoji, Ootsuka, Kiyomi, Kanao, Kenichi, Narasaki, Katsuhiro
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.06.2021; Elsevier BV
• Subjects: Astronomy; Design specifications; End of life; Joule-Thomson cryocooler; Lifetime test; Space missions; Two-stage Stirling cryocooler; STB; STD; STC; STH; CPT; GM; JT; MLI; Joule-Thomson cryocooler; JTCH; JTCL; 2ST; Two-stage Stirling cryocooler; Lifetime test; HEX
• ISSN: 0011-2275; 1879-2235
• DOI: 10.1016/j.cryogenics.2021.103306

•The 4K Joule-Thomson cryocooler was tested to verify its lifetime.•Over three-year operation was successfully demonstrated.•Performance of the subcomponents was evaluated over the long term.•The cooling performance diagram with various drive conditions was obtained. The 4K Joule-Thomson (JT) cryocooler is a key cryogenic component for future astronomy missions such as ATHENA and LiteBIRD. It was originally developed for SMILES (2009) and upgraded for ASTRO-H/SXS (2016) and SPICA. The 20K two-stage Stirling cryocooler developed for AKARI (2006) was also upgraded and used as a precooler. The operational life is a critical factor in planning long-term missions. An engineering model of the 4K-JT cryocooler was built for continuous operation to verify its lifetime. Testing was done from 2010 to 2019 and successful three-year operation was demonstrated with an extended operation; this was beyond the design specification. This paper describes the overall history of the lifetime test of the 4K-JT cryocooler and an evaluation of the end-of-life cooling performance and performance changes during long-term operation.