The aging of electrical insulation at cryogenic temperatures

The author points out that the application of superconductive conductors requires the development of electrical insulation capable of operating for many years at temperatures as low as 4 K and ranging to ~100 K for the most recent superconductors. The insulation is subjected to stresses caused by the cryogenic environment, possibly high pressures and radiation, in addition to the electrical stresses associated with service. Experimental results of aging tests for small samples are reported, and operating experiences with superconducting devices in service for about a decade are discussed