Measurement and Analysis of an Angular Neutron Flux on a Beryllium Slab Irradiated with Deuterium-Tritium Neutrons

Abstract

Angular neutron fluxes leaking from the surface of beryllium slab assemblies have been measured with irradiation of deuterium-tritium neutrons. The experiment was performed using the time-of-flight technique with an NE-213 scintillation detector. The measured neutron energy range was from 50 keV to 15 MeV. The thicknesses of the slabs were 50.8 and 152.4 mm, and the measured angles of the angular fluxes were 0.0, 12.2, 24.9, 41.8, and 66.8 deg. The experimental results have been compared with the results calculated by the Monte Carlo codes, MORSE-DD and MCNP, using the data of beryllium in the JENDL-3PR1, ENDF/B-IV, and Los Alamos National Laboratory nuclear data files. The results calculated with these files showed discrepancies of 20 to 30% from the experimental results. It was pointed out that the angular distributions of an elastic cross section and the total cross section of an inelastic reaction for 14.8-MeV neutrons in the files were insufficient to reproduce the measured spectra.