An organic potting material, Epoxy Resin, was exposed to γ-rays at the liquid nitrogen temperature 77K and its mechanical properties such as elastic modulus, breaking stress, and breaking strain, were measured at the same temperature.
The gamma-irradiation exceeding 10⁷R led to small reduction of elastic modulus, which was concluded due to the cleavage of principal chain of polymer. The frequency distribution of the measured values concerning structure-sensitive properties such as breaking stress and/or breaking strain was found not to fit the Gaussian curve after irradiation. This distribution had a tail component in the lower region, which suggested an introduction of “local” weak spots in potting material of the superconducting magnets during operation under irradiation.