In the present study the bulk etch rate, the bulk activation energy, the track density and
the degree of crystallinity percentage have been examined for gamma irradiated samples with 60Co
source at doses ranging from 0 to 200 kGy. After gamma irradiation the samples were exposed to
zirconium sand to collect a-particle tracks. Samples were etched at 60, 65, 70, 75 and 80 C in
6.25 N NaOH solution for 4 h. Results indicated that, the bulk etch rate increases with the increase
of gamma absorbed dose at different etching temperatures. The bulk activation energy and the
track density decreased with the increase of the gamma absorbed dose. The degree of crystallinity
percentage for un-etched and etched samples also has been studied for different gamma doses. The
increase in bulk etch rate and the decrease in both of bulk activation energy and track density with
increase in the gamma dose may be due to the degradation in CR-39 polymeric material.