Abstract:Space exploration missions require cryocoolers to provide cooling power in different temperature regions. The two-stage high frequency pulse tube cryocooler is a potential solution. A thermally coupled two-stage high frequency pulse tube cryocooler is presented. To improve the compactness, its two cold fingers are both shaped in coaxial type. The no-load temperature of 22.03 K is achieved in the phase shifting with only a room temperature inertance tube. For a total input electric power of 413 W, both 8 W@80 K and 1 W@30 K can be obtained at two stages. Experimental study is carried out for its cooling performance at different precooling temperatures. The changing rule of the efficiency of cold fingers at low temperature stages is obtained.