High-Performance Cryogen-Free Platform for Microkelvin-Range Refrigeration

Improved accessibility to the microkelvin temperature regime is important for future research in quan-tum materials, for quantum information science, and for applications of quantum sensors. Here, we report the design and performance of a microkelvin platform based on a nuclear-demagnetization stage, engineered and well optimized for operation on a standard cryogen-free dilution refrigerator. PrNi5 is used as the dominant refrigerant. The platform provides a large area for mounting experiments in an ultralow-temperature low-electromagnetic-noise environment. The performance is characterized using current-sensing noise thermometry. Temperatures as low as 395 mu K are reached and a protocol is estab-lished in which it is possible to operate experiments below 1 mK for 95% of the time, providing an efficient cryogen-free microkelvin environment for a wide range of science applications.