A new sensitization technique combining CO2 and UV treatments for improved neutron dosimetry of CR-39 track detectors

Abstract

A new sensitization technique combining carbon dioxide and UV treatments was investigated for improved neutron dosimetry of CR-39 track detectors. The detectors were irradiated with an 241Am–Be neutron source in a low-scatter laboratory facility, delivering a personal dose equivalent Hp(10) of 1 mSv. Prior to their chemical etching, the detectors were treated in carbon dioxide at a pressure of 0.6 MPa for 6 days followed by a UV (254 nm) treatment at a distance of 5 cm from the lamp, for 20 h. The opposite, UV followed by carbon dioxide treatment, was also investigated. The qualitative impact of these treatments on the background noise of the detectors, and their track size distributions compared to only carbon dioxide, only UV treated detectors, and untreated ones was analysed. Overall, the technique combining CO2 and UV treatments, independently of their order, increased the sensitivity by about 40% and 120% compared to the UV treatment alone and the untreated detectors, respectively, and reduced approximately 15% compared to the CO2 treatment alone. It also significantly enhanced the average diameter of the tracks compared to both treatments separated, allowing a better distinction between real tracks and the noisy background.