A Miniature Helium Liquefier-Cryostat of Cascade Type

Abstract

A miniature cascade helium liquefier-cryostat is described which will cool from room temperature to 4.2°K in half an hour and enables continuous experiments to be carried out at or near this temperature, or at intermediate temperatures, for as long as required. It consumes only liquid oxygen and hydrogen from high-pressure cylinders, is extremely economical in its consumption of these materials, and incorporates a number of new features which make its operation almost automatic after the starting-up period.