Improvement of the two-stage Stirling cooler below 20K

Abstract

Sumitomo Heavy Industries，Ltd. (SHI) supplies 4K-class and 1K-class cooler for space use. The 4K-class and 1K-class cooler consists of Joule-Thomson (JT) cooler and two-stage Stirling cooler as a pre-cooler. To improve the cooling capacity of 4K-class and 1K-class coolers， we are developing the cooling capacity of two-stage Stirling cooler below 20K. The performance of the two-stage Stirling cooler essentially depends on the volumetric heat capacity of its regenerator. We investigated new materials which has higher volumetric heat capacity than stainless steel used in current model. This paper describes the results of cooling tests of the two-stage Stirling cooler using new materials.