Radiation damage of plastic scintillators

Abstract

Degradation and annealing mechanisms in polystyrene were studied in order to account for the losses in transmittance and light yield observed in polystyrene-based plastic scintillators. Special emphasis was put on irradiations in oxygen and on the oxygen annealing process. These experiments indicated that: (a) irradiations in which oxygen was continuously available throughout the bulk of the polystyrene sample were the most damaging; (b) during the oxygen annealing process, the annealing rate was proportional to the oxygen diffusion rate; and (c) oxygen reacted with free radicals in the sample, contributing to an increase in permanent radiation-induced absorption.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>