Effects of high gamma doses on the bulk etch rate of two grade CR-39 materials

摘要

In thSU study, the effect of gamma pre-treatment on etching rates has been investigated on CR-39 detectors manufactured by Pershore Mouldings (PM) as standard grade and (PM355) as dosimetry grade. The detectors have been exposed to Co-60 gamma rays at absorbed dose ranging from 0 to 10(5) Gy. The chemical etching was carried out in four PEW solutions (potassium ethanol in water) with various concentrations (KOH 6.25 N with 0%, 20%, 40% and 60% of ethanol). The reSUlts show that the effect of gamma rays on CR-39 etching characterSUtics SU more pronounced when the ethanol concentration increases in the etching solution especially in the region ranging from 103 to 104 Gy. In thSU range, V-B etching rate decreases till values less than those observed for virgin material. The structural alterations (cross linking or main chain scSUsions) produced by gamma rays in thSU plastic detector have been determined using UV-vSUible and FTIR spectroscopy and compared to those induced by proton irradiation.