RÉSUMÉ
Objective To increase externally-assigned response, improve energy response of CR39 and develop positive fast/thermal neutron personal dosimeter applicable for occupational exposure in oil and gas field logging by using pre-recoil layer.Methods The externally-assigned response of CR39 detector was improved through increasing the track density by using the α particle induced by the reaction of 10B(n,α) 7Li with the BN as pre-recoil layer, and the increase was vilified by using both Monte-Carlo simulation and experiment exposed by standard neutron source.Results Fast/thermal neutron personal dosimeter's neutron flux sensitivity and neutron dose equivalent sensitivity were 3.46 × 10-4 track per 0.013 and 52.8 mSv.According to theoretical derivation and experiment of standard 241 Am-Be neutron source, detecting efficiency and energy response of CR39 were effectively improved, and quantitative measurement of dose contributed by thermal neutron was realized.Conclusions CR39 fast/thermal neutron personal dosimeter of high sensitivity is applicable to oil and gas field logging environment and of potential development.