Method for obtaining improved temperature regulation when using liquid helium cooling

摘要

A method for controlling the flow of a cooling medium such as helium into an insulated chamber surrounding a region to establish a stable thermal environment in the region over a wide range of cryogenic temperatures. A thermally insulated capsule surrounds a variable temperature capillary to precondition the helium before it flows into the insulated chamber. The capillary can be operated in different modes, depending upon the heating or lack of heating of the capillary. At low temperatures the capillary can pass the helium in its liquid phase, at high temperatures only a small amount of gaseous helium is passed, and at certain intermediate temperatures there is an ample flow of gaseous helium only.