POSTIRRADIATION SENSITIZATION OF CR-39 TRACK DETECTOR IN CARBON-DIOXIDE ATMOSPHERE

The effect of post-irradiation treatment of CR-39 track detector in ca rbon dioxide atmosphere on the alpha particle registration sensitivity was investigated. Significant increase in etch rate ratio for 6.1 MeV Cf-252 alpha particles was observed. The sensitization increased both as a function of treating time and as a function of carbon dioxide pr essure in the treating vessel. Energy dependence of the sensitization was found to be small in the 2-9 MeV alpha particle energy interval. F ading of latent tracks after the sensitization process was slow in a o ne day period. Pre-irradiation treatment in carbon dioxide showed also some sensitization, though to a lesser extent than post-irradiation t reatment. However, exposing CR-39 to alpha particles in pure carbon di oxide atmosphere resulted in dramatic decrease in sensitivity. The rol e of dissolved oxygen and carbon dioxide in the primary latent track f ormation and in post-irradiation latent track transformation is discus sed. Potential influence of the application of sensitization of CR-39 in radon, neutron and cosmic ray charged particle dosimetry is also di scussed.