An electronic demagnetization stage for the 0.5K to 1.8K temperature range

We have designed and built a demagnetization stage to operate between 1.8K and 0.5K, a somewhat unusual temperature range for adiabatic demagnetization refrigeration. The lower bound in temperature is dictated by the thermal performance of our super(3)He gas heat switch, the upper by NASA specifications. We intend this demagnetization stage to be the first stage of a proposed two-stage continuously operating adiabatic demagnetization refrigerator (ADR) which will operate between 1.8K and 50 mK. Here we discuss thermal, mechanical, magnetic and chemical considerations which led to novel features in our salt pill design.