The State of the Art: Lightweight Cryocoolers Working in the Liquid-Helium Temperature Range.

Liquid-helium temperature is a widely used working temperature in low-temperature physics. At present, liquid-helium or low-frequency cryocoolers, including Gifford Mahon (GM) cryocoolers or GM pulse tube cryocoolers, are usually employed to obtain a cooling temperature of about 4 K. The use of closed-cycle mechanical cryocoolers to replace liquid helium and the development of mechanical cryocoolers toward lightweight are advantageous development directions for refrigeration technology, and certain progress has been made in recent years. This paper summarizes the development status of lightweight cryocoolers, including Joule–Thomson cryocoolers, high-frequency pulse tube cryocoolers, and Vuilleumier cryocoolers, which have the advantages of small size and low power consumption compared with GM-type cryocoolers. The evolutionary ideas of miniaturization, the research advances, the characteristics of different types of cryocoolers, and the future development directions are also systematically introduced. [ABSTRACT FROM AUTHOR]