3He/4He refrigerator based on closed cycle cryocooler.

A. Chernikov*, A. Buzdavin, F. Cherviakov

Abstract – The 3He/4He refrigerator based on the 150 mm shaft cryostat and the closed cycle cryocooler GM SRDK415D (Sumitomo) is described. In a single mode, the final temperature of the 3He refrigerator was 0.52 K. In a continuous mode with 3He, the final temperature was 0.78 K. Using 3He without external pumping a retained mode of temperature is achieved in the range of (1.0 - 1.5) K with positive drift +(10-15) mK/h for 11 days.

In the 4He liquefaction mode at a temperature of 4.2 К, a cooling efficiency of 1.6 W was obtained. In the continuous mode with the liquid 4Не vapor pumping the final temperature was 1.4 К.

Both of the helium isotopes were pumped out by the oil-free spiral pump XDS35i.