Low-temperature electron irradiation of insulating films and adhesives

The effects of electron irradiation at 4 K on candidate electrical insulating materials for the Superconducting Supercollider (SSC) were studied. Following 4-K irradiation to a dose of 3.7 x 109 rad, storage at 77 K, and warm-up to room temperature, tensile and lap-shear tests were conducted at 4 K on six types of polyimide films and eleven types of adhesive-film combinations, respectively. These results are compared with results of control tests conducted at 4 K. Following irradiation, all polyimide films exhibited some degradation of tensile strength, but most adhesive-film combinations showed little change in strength.