ヘリウム冷凍機におけるコールドコンプレッサの役割と期待

Abstract

Since around 1970, cryogenic systems have required the use of cold compressors. The requirement appeared for two reasons, The first was reduce the pressure of liquid helium with the intention of realizing the stable operation of large superconducting magnets with the best superconducting ability by decreasing operating temperature. The other was to improve the reliability of helium refrigerator compressors by introducing a turbo-compressor with oil-free bearings. This paper describes the circumstances and particular development of cold compressors, requirements related to helium refrigeration systems and cold compressors and future prospects.