Determination of uranium and thorium contents inside different materials using track detectors and mean critical angles

The critical angles of the CR-39 (θc) and LR-115 type II (θc′) solid state nuclear track detectors (SSNTD) for detecting α-particles emitted by the uranium and thorium series have been evaluated by calculating the corresponding ranges of the emitted α-particles in different material samples and in the SSNTD studied. The influence of the emitted α-particles initial and residual energies on the critical angles of the SSNTD studied has been investigated. The uranium and thorium contents of different geological samples have been evaluated by exploiting data obtained for the critical angles of the CR-39 and LR-115 type II solid state nuclear track detectors and measuring the corresponding densities of tracks.