3He Cryostat with Adsorption Pumping

Abstract

A ³He cryostat is described in which temperatures down to 0.3°K have been obtained by pumping the ³He refrigerant bath with activated charcoal at a temperature of 1.3°K. The performance characteristics of the adsorption pump are described in some detail, and a discussion is given of the extent to which the speed, adsorptive capacity, and cooling requirements of such a pumping system can be predicted by calculation.