Two-Stage Pulse Tube Refrigerator for 20 K Operation

Abstract

This paper describes the experimental results of a two-stage pulse tube refrigerator. The purpose of this study is to obtain a lower refrigeration temperature compared with a single stage pulse tube refrigerator. A low vibration linear-motor drive compressor was designed for the two-stage pulse tube refrigerator. As a preliminary experiment, the refrigeration performance of the two-stage pulse tube refrigerator was investigated in combination with a compressor of a commercial GM refrigerator. The lowest temperature achieved was 19.1 K and the refrigeration capacity at 20 K was 100 mW. Lastly the experimental results of the pressure waves in the first and second pulse tubes are shown for the case when the openings of the orifice and double inlet valves are changed.