Progress in the Development of a Continuous Adiabatic Demagnetization Refrigerator

Abstract

In this paper we summarize recent progress in the development of an adiabatic demagnetization refrigerator (ADR) that operates continuously at sub-Kelvin temperatures. The ADR uses multiple stages, one of which cools a load while the others periodically transfer heat to a heat sink. The architecture is very flexible, allowing stages to be added at the low end to achieve lower operating temperature, or at the high end to increase the heat rejection temperature. The present design goals are to achieve high cooling power (on the order of 10 ?W) at 50 mK or lower, and heat rejection at 6 K or higher. The latter reflects the performance goals of various cryocoolers being developed for use in space through NASA’s Advanced Cryocooler Technology Development Program1. Over the past year we assembled and tested a 3-stage ADR that used a superfluid helium bath as a heat sink. We have also recently assembled a 4-stage ADR that can operate with a 4.2 K helium bath. Details of the design, operation and performance of these systems are discussed.KeywordsHeat SinkCooling PowerHeat RejectionGadolinium Gallium GarnetHelium BathThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.