Thermoluminescence of gamma-irradiated polyethylene in high temperature region

Gamma ray was irradiated to high density and low density polyethylenes (HP and LP) at room temperature in the atmosphere to examine their absorbed dose dependence to the thermoluminescence peaks, atmospheric effect and hexane treatment effect at the time of irradiation. The phenomenological analysis was forwarded on the relations between the peaks appeared at higher than room temperature and carrier trap and luminescence centre. On HP thermoluminescence curve, the Pb peak exists at 55+-5deg, and the Pa peak exists near the melting point of crystals, while only Pa' peak exists in LP. When isothermal decrement is allowed to the Pb peak of HP at room temperature after finishing γ-ray irradiation, the luminescence intensity decreases with the lapse of time, and its decrement constant is about 6.2 hours. The wave length of luminescence at the Pb peak was mostly 550 nm. The Pa and Pa' peaks relate to the recombination accompanying the crystal fusion of the recrystallization centre remaining in the crystals and the carrier expelled from crystalline region by γ-ray irradiation. (Kobatake, H.)