Development of Adiabatic Demagnetization Refrigerator for Future Astronomy Missions

Abstract

The superconducting microcalorimeter provides astronomers with a new tool to probe the hot universe. This kind of detectors has superb energy resolution and high detection efficiency, which is important for diffuse X-ray detection. Astronomy missions, such as the Hot Universe Baryon Surveyor (HUBS) and Diffuse X-ray explorer (DIXE) proposed in China, is going to employ superconducting microcalorimeters. The superconducting microcalorimeter works in its superconducting transition region, which is at a very low temperature(<100 mK). Realization of such a low temperature in space is challenging. Adiabatic demagnetization refrigerator (ADR) is a good candidate for milli-Kelvin cooling system. Here we introduce our recent work on ADR design and construction. Most of the key components for building an ADR have been designed and fabricated. Recently we integrated all components and built a two stage ADR. Preliminary performance on each stages test has been conducted separately. In its performance test, starting from 4 K, the FAA stage could cool down to 156.7 mK and the GGG stage could reach 768.4 mK. This result shows promise for future development.