Response function of a fast neutron capture-gated spectrometer

Abstract

The response function of a fast neutron capture-gated detector with a simple geometry has been simulated with the aim of studying the mechanism of its formation. The Geant4 package and the DGEOM program developed by the Institute for Nuclear Research especially for studying processes of fast neutron moderation in an organic medium have been used for numerical simulation of the response function. The response functions and the detection efficiencies of an actual detector for neutron energies of 1.2, 2.4, 5.0, and 14.6 MeV have been reconstructed and analyzed. The behavior of the response function has been comprehensively analyzed in the neutron energy range of 1–14 MeV. It is shown that our simulation adequately represents the experimental data and that the response function of the detector has a double-peak structure deteriorating its energy resolution. Taking into account the interaction with carbon for neutrons with energies of <15 MeV affects the response function only slightly. The consistency of the physical model involved in the DGEOM program and the adequacy of the simulation results obtained using this program are demonstrated.