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A 1-2 K Cryogenic System With Light Weight, Long Life, Low Vibration, Low EMI and Flexible Cooling Capacity for the Superconducting Nanowire Single-Photon Detector

This paper presents a 1-2 K cryogenic system for cooling the superconducting nanowire single-photon detector (SNSPD). The system is based on the Stirling-type pulse tube cryocooler (SPTC) and the Joule-Thompson (JT) cryocooler technologies and thus named as the hybrid cryogenic system. It eliminates any moving component at the cold end which endows it with evident advantages over the Gifford-McMahon (GM) cryocooler in terms of low vibration, low electromagnetic interference (EMI) and long life. It can operate at 1-2 K and has an expected mean-time-to-failure of 10 years. The overall weight is below 30 kg, which makes it an attractive cryocooler candidate for the space applications. Furthermore, the operating temperature can be adjusted conveniently for the SNSPD other than being at a fixed temperature as the superfluid helium does. The design approaches and system integration are described in detail, and the performance characteristics presented and discussed. The cooling system has an experimental cooling temperature of 1.52 K. It is also expected to reach 1 K and below provided that the further performance improvement is conducted.