Experimental Performance of a Single Stage Superfluid Stirling Refrigerator Using a Small Plastic Recuperator

The experimental performance of the first superfluid Stirling refrigerator (SSR) to use a plastic recuperator is reported. This SSR is a single stage machine, has a total internal volume of 83 cm3, and uses a 3 cm3Kapton heat exchanger. Operating from a high temperature of 1.0 K and with a 1.5%3He–4He mixture, this SSR achieves a low temperature of 344 mK and delivers net cooling powers of 1.86 mW at 750 mK, 358 μW at 500 mK, and 97 μW at 400 mK. Cooling power versus cold piston temperature for various frequencies of operation and for two piston stroke configurations are provided.