Model for Calculating Prompt-Response Self-Powered Neutron Detectors

Abstract

A sophisticated model is presented for the calculation of prompt-response self-powered neutron (SPN) detectors used for stationary as well as nonstationary neutron flux measurements in nuclear reactor cores. The technique recommended for calculating the unit sensitivity in terms of A/(cm) per unit flux takes the following into account: neutron self-shielding factor of the emitterflux depression correctionCompton and photoelectron production rate due to self-absorption of the gamma-ray cascade emitted immediately after neutron capture, electron escape probability from the emittermloss of electron energy within the emitterorange of the electrons in the insulator which contains a space-charge electric field.Calculated thermal and fast unit sensitivities in a typical light-water-reactor neutron spectrum for four potential prompt-response SPN detectors, whose emitters consist of cobalt, cadmium, erbium, and hafnium, are compared with experimental data and are found to be in satisfactory agreement.