Effect of Irradiation Temperature and Atmosphere on Aging of Epoxy Resins for Superconducting Magnets.

The superconducting magnets of future particle accelerators will be exposed to high irradiation doses at cryogenic temperatures. To investigate the effect of irradiation temperature and atmosphere on the aging behavior, we have characterized the changes in thermomechanical properties of six epoxy resins for potential use in superconducting magnets after irradiation up to 20 MGy in ambient air, inert gas, and liquid helium. Based on the results obtained by Dynamic Mechanical Analysis (DMA), we discuss the effect of irradiation temperature and the presence of oxygen. The irradiation temperature can have a strong influence on the rates at which cross-linking and chain scission occur.