Continuous Refrigeration between 4.2 and 1°K
Refrigeration between 4.2 and 1°K is commonly produced by the evaporation of liquid He4 from a thermally isolated bath maintained at the appropriate pressure by means of a vacuum pump. In the majority of experimental assemblies, a bath temperature of 1.25°K can be produced without difficulty at which temperature the saturation vapor pressure is slightly less than 1 mm Hg. When the liquid in the bath reaches a certain minimum volume, the experiment must be discontinued, at least temporarily, while the bath is returned to atmospheric pressure and a further supply of liquid at 4.2°K is added. Thereafter, there is an additional loss of liquid while the bath is again pumped down to the operating pressure.
KeywordsVacuum Pump Bath Temperature Storage Volume Experimental Assembly Valve Seat
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