Alternative method for thermal neutron flux measurements based on common boric acid as converter and LR 115 detectors

摘要

A method to determine the flu and angular distribution of thermal neutrons with the use of LR-115 detectors was developed. The use of the LR-115 detector involves the exposure of a pressed boric acid sample (tablet) as a target, in tight contact with the track detector, to a flu of thermalized neutrons. The self-absorption effects in thin fil or “foil” type thermal neutron detectors can be neglected by using the LR-115 detector and boric acid tablet setup to operate via backside irradiation. The energy window and the critical angle-residual energy curve were determined by comparisons between the experimental and simulated track parameters. A computer program was developed to calculate the detector registration efficien y, so that the thermal neutron flu can be calculated from the track densities induced in the LR 115 detector using the derived empirical formula. The proposed setup can serves as directional detector of thermal neutrons.