Helium Joule-Thomson cryocooler below 4.5 K for infrared detectors

Mechanical cryocooler technology are one of the significant technologies for earth and space scientific exploration. To meet the needs of future applications of infrared and millimeter wave detectors, Shanghai Institute of Technology Physics, Chinese Academy of Sciences (SITP, CAS) has developed a helium Joule-Thomson cryocooler (JTC) below 4.5 K for space applications. As the two most important components of the helium JT cryocooler, the precooler and the JT compressor are both developed by SITP. The precooler is a two-stage pulse tube cryocooler, and the JT compressor is an oil-free linear compressor, all of which can achieve long-life operation. First, a 4 K JTC was developed, experimental results show that after about 11 hours of cooling, the 4 K JTC successfully reached the liquid helium temperature and has a cooling performance of at least 110 mW@4 K.