Cryogenic electrical properties of irradiated cyanate ester/epoxy insulation for fusion magnets

[摘要] The insulation materials used in high field fusion magnets require excellent mechanical properties, high electrical breakdown strength, good thermal conductivity and high radiation tolerance. Previous investigations showed that cyanate ester/epoxy (CE/EP) insulation material, a candidate insulation for fusion magnets, can maintain good mechanical performance at cryogenic temperature after 10 MGy irradiation and has a much longer pot life than traditional epoxy insulation material. In order to quantify the electrical properties of the CE/EP insulation material at low temperature, a cryogenic electrical property testing system cooled by a G-M cryocooler was developed for this study. An insulation material with 40% cyanate ester and 60% epoxy was subjected to60Co γ-ray irradiation in air at ambient temperature with a dose rate of 300 Gy/min, and total doses of 1 MGy, 5 MGy and 10 MGy. The electrical breakdown strength of this CE/EP insulation material was measured before and after irradiation. The results show that cryogenic temperature has a positive effect on the electrical breakdown strength of this composite, while the influence of60Co γ-ray irradiation is not obvious at 6.1 K.

[发布机构] State Key Laboratory of Technologies in Space Cryogenic Propellants, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing; 100190, China^1;University of Chinese Academy of Sciences, Beijing; 100049, China^2

[关键词] Cryogenic temperatures;Electrical breakdown strengths;Epoxy insulation;Gamma-ray irradiation;High electrical breakdown;Insulation materials;Mechanical performance;Radiation tolerances