Design and performance of the J-T component of dry dilution refrigerator

An effective J-T component is crucial for the operation of dilution refrigerator due to its function as a 3 He liquefier in a refrigeration cycle. This paper briefly introduces the principle of the J-T component in dry dilution refrigerator, studies the influence of J-T component on the still and its design method. An effective J-T component is designed to cool over 3 K of 3 He gas to almost 1 K of 3 He liquid. The basic still temperature is below 0.5 K in a dilution refrigerator prototype. In this prototype, a two-stage step heat exchanger was adopted to obtain the lowest temperature below 26 mK.