Rapid sample changes in directly loaded cryostat - having rod which is inserted through gas seal in five minutes using helium isotope system

摘要

Mixer cryostat is directly loaded to allow rapid change of samples for physical measurement on the samples. It has a support rod for the sample which projects down into the sample chamber when the cryostat is operating but which can be removed from it. The pipe leading down through which the rod passes is made vacuum tight against the atmos. and is joined to the bath. It passes through the distn. zone and the cooling heat exchanger. The cryostat uses the 3He-4He system. Used in testing samples at very low temps. esp. =0.3 degrees K. The use of the 3He-4He system is known but existing systems take up to a week for a sample to be changed over.