Compact Stand-Alone Refrigerator for Operating at Temperatures up to 0.35 K

A compact autonomous cryostat operating on the basis of a closed-loop Gifford-McMahon cryocooler of industrial production with an operating temperature of up to 0.35 K is described. The cryostat does not have external pumps or other communications except for those necessary for the operation of the cryocooler compressor. The operating temperature is ensured by sorption pumping of isotope vapors 4He and 3He. The required gas supply is constantly kept inside the cryostat. The height of the cryostat body is 600 mm, the diameter of the body is 250 mm. The gas condensation time is less than 1 h, and the duration of continuous operation is up to 12 h (it depends on the power released in the cold stage).