Effect of heat treatment on some properties of CR-39 nuclear track detector irradiated by gamma ray

The present study aims to determine the effect of heat treatment on the bulk etch rate of un-irradiated and gamma irradiated CR-39 detector. Track density and the damage in samples surface due to the heat treatment have also studied for the un-irradiated and gamma irradiated CR-39 detector. The samples of CR-39 polymer track detector has been exposed to γ-ray from 60Co source with doses 0, 10, 50, and 100 kGy then exposed to α-particles from the air radon gas. These samples have been annealed at 50, 100 and 150 °C for different annealing times then etched in 6.25 N NaOH solution at 70 °C for 6 h. The variation of bulk etch rate and the track density as a function of annealing temperature have been studied. The bulk etch rate increases with gamma dose and with increasing both of the annealing time and the annealing temperature. The decrease of track density with increasing the annealing time and the damage of annealed gamma irradiated CR-39 samples clarify serious degradation under the effect of heat treatment