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 a ngular-dependent alpha-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 registra tion probabilities for CR-39 and LR-115 are different for each radioac tive chain, exposition of the two detectors to a sample by contact aut oradiography allows separating the contributions of each family in a s ample. This SSNTD method applied to Moroccan phosphates has given conc entrations consistent with those found by gamma-ray spectroscopy. (C) 1998 Elsevier Science Ltd. All rights reserved.