Simulation and experimental characterization of an energy-extended neutron long counter

BackgroundThe measurement of high-energy neutrons is becoming more and more important in the evaluation of dose caused by space neutrons and the radiation protection of particle accelerators.PurposeThe study aims to investigate the performance of an energy-extended neutron long counter.MethodsThe energy-extended neutron long counter was designed based on De Pangher type. The (n, xn) multiplication reaction between neutrons and metallic materials was utilized to improve the high-energy response of neutron long counter by adding metal chromium and lead materials into the moderator of the neutron long counter. Then, the structure of the neutron long counter was optimized by using Monte Carlo simulation to obtain the maximum value within the energy range of 1 keV~20 MeV and 1 keV~150 MeV, respectively. Finally, the effective center and energy response of the long neutron counter were measured by Am-Be neutron source and D-T neutron source in the standard radiation field.ResultsThe calculated response curve shows that the deviation of the maximum value from the average value is 12.2% in above energy range. The comparison between experimental results and the Monte Carlo simulation results shows that the theoretical calculation is consistent with the experiment within the error range.ConclusionThe upper energy limit of the long neutron counter can be extended by embedding metallic lead and chromium materials in the inner polyethylene layer of the long neutron counter.