Feasibility study on neutron energy spectrum measurement utilizing prompt gamma-rays

Abstract A new approach based on Prompt Gamma-ray Neutron Activation Analysis (PGNAA) was proposed for measuring neutron energy spectra. A system, which consisted of a high purity germanium (HPGe) detector and a multi-layer sample, was used to validate the method. The composite layers of the sample comprised of lead, polymethyl methacrylate, sodium chloride powder and borated polyethylene. Prompt gamma-rays emitted from Pb, H, O, C, Cl and B were selected to determine the incident neutron energy spectrum. The response function for the production of gamma rays from these elements by monoenergetic neutrons was obtained through Monte Carlo simulations. Then the neutron fields of Cf-252 neutron source and D-T neutron generator were investigated with this approach. With the measured prompt gamma-rays and the response matrix, the neutron spectra were obtained through the PSO algorithm. The unfolded results have a good agreement with the simulation spectrum.