Liquid helium evacuating refrigeration systems and common problems

The liquid helium evacuating refrigeration system is widely used for temperatures from 1—4 K. This paper briefly analyzes the principle and present status of liquid helium pressure refrigeration systems, then explain the principle, design of the components, and aspects that should be considered in usage. The key component of a liquid helium cooling system, the flow resistance, is described in detail, as well as its current development status and prospects. Finally, common problems and their prevention and treatment are enumerated.