Use of Cr-39 Polymer for Radiation Dosimetry

This paper discusses the results of investigations of beta and gamma radiation induced thermoluminescence (TL) of CR-39 polymer. As the material is cheap and easily available, the feasibility of CR-39 being used for personal dosimetry is worth investigating. Samples from CR-39 of dimensions 3mm × 3mm were classified into two main groups. The first group was irradiated with gamma rays from 137Cs source, while the second group was exposed to beta particles from 90Sr source and read for TL emission on a TLD reader, Harshaw 4500. The chips were annealed at different temperatures to find out optimum annealing temperature to get rid of the background to a maximum. Different annealing times were also studied for optimization. The heating temperatures in the TL reader were studied in a wide range so as to assess the best possible heating temperature. The possible enhancement of TL response of CR-39 exposed to gamma rays in the presence of oxygen and carbon dioxide was also studied. Dose response of CR-39 exposed to gamma rays in the presence of oxygen is better than that in the presence of carbon dioxide. The response of the exposed polymer in the presence of carbon dioxide is found to be better than that in the presence of air.