Monte-Carlo detection probabilities for SSNTD application to uranium and thorium analysis in Moroccan phosphates

A Monte-Carlo technique has been applied to calculate the energy and angular-dependent α-particle registration probability of the solid state nuclear track detectors (SSNTD) CR-39 and LR-115 for members of the uranium and thorium radioactive families. Since the total registration probabilities for CR-39 and LR-115 are different for each radioactive chain, exposition of the two detectors to a sample by contact autoradiography allows separating the contributions of each family in a sample. This SSNTD method applied to Moroccan phosphates has given concentrations consistent with those found by γ-ray spectroscopy.