A Retrospective on how Cryostats have changed with Cryostat Use and the Cooling Methods used to keep Superconducting Magnets Cold

Abstract

Prior to the invention of the vacuum flask by James Dewar in 1895, cryogenic temperatures below 100 K could not be sustained very long. The Development of the modern cryostat was an extension of the basic Dewar vacuum flask. The design of the cryostat, its insulation, and the cold mass support system is a function of the cryostat’s intended use. The type of refrigeration available also influenced the development insulation systems, support systems, transfer lines and electrical leads that are part of the cryostat. In recent years the availability and the cost of helium has been a significant factor in cryostat design and the methods used to cool and cool-down cryostats. This paper explores the historical development of today’s cryostats and how that can be tied to the source of cryogenic cooling. This paper is focused on earth bound cryostats. Some of the same principles can be applied cryostats used in space.