A new method for evaluating radon and thoron α-activities per unit volume inside and outside various natural material samples by calculating SSNTD detection efficiencies for the emitted α-particles and measuring the resulting track densities

A Monte Carlo computer code for determining detection efficiencies of the CR-39 and LR-115 II solid-state nuclear track detectors (SSNTD) for α-particles emitted by the uranium and thorium series inside different natural material samples was developed. The influence of the α-particle initial energy on the SSNTD detection efficiencies was investigated. Radon (222Rn) and thoron (220Rn) α-activities per unit volume were evaluated inside and outside the natural material samples by exploiting data obtained for the detection efficiencies of the SSNTD utilized for the emitted α-particles, and measuring the resulting track densities. Results obtained were compared to those obtained by other methods. Radon emanation coefficients have been determined for some of the considered material samples.