Radiation damage of plastic scintillators

This paper reports on radiation damage studies performed on polystyrene-based plastic scintillators which contained p-terphenyl plus either BBQ, 3HF, or dimethyl-POPOP as dopants. Several identical sample sets were prepared to observe, in different experiments, the effects of dose rate (1 Mrad/h vs. 30 Krad/h) and environment (n2 vs. Ar vs. H2). Transmittance and light yield measurements performed before irradiation, after irradiation, and after an oxygen annealing period showed no significant differences in the radiation susceptibility of the scintillators under the different experimental conditions. These experiments indicated that: (Irradiations in which oxygen is continuously available throughout the bulk of the polystyrene sample are the most damaging; During the oxygen annealing process, the annealing rate is proportional to the oxygen diffusion rate; and Oxygen reacts with free radicals in the sample, contributing to an increase in permanent radiation-induced absorption