A variable heat switch for use below 1° K

Abstract

In the course of some heat capacity measurements at low temperatures, we have developed a superconducting heat switch whose thermal conductivity can be varied over a substantial range. Thus, with the switch connecting a calorimeter and a paramagnetic refrigerant, it is possible, by balancing the natural heat leak into the calorimeter, to obtain isothermal conditions over a wide range of temperatures below 1º K.

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