Investigation of proton response of CR-39

CR-39 type super grade PM-355 samples have been irradiated at normal incidence with monoenergetic protons at selected energies in the range of 0.2 to 5 MeV. The sensitivity function and its variation with energy have been experimentally determined. A clear shift was observed in the maximum sensitivity towards higher proton energies with the increase in etching time. The critical angle for proton registration decreases rapidly between 0.2 MeV and 0.5 to 0.8 MeV depending on the etching time. For higher energies the critical angle increases gradually. The CR-39 detection efficiency for protons was found to be about 100% within the experimental accuracy for all energies in comparison with that of a surface barrier detector.