Analysis of Neutron Scattering and Gamma-Ray Production Integral Experiments on Nitrogen for Neutron Energies from 1 to 15 MeV

Monte Carlo transport calculations were made to analyze the results of two integral measurements of neutron scattering and gamma-ray production from liquid nitrogen samples. The experimental data from Intelcom Radiation Technology and Oak Ridge National Laboratory (ORNL) were given as angular-dependent NE-213 detector count rates of neutrons and gamma rays scattered from a spherical nitrogen Dewar pulsed with a 1- to 20-MeV neutron source. ORNL results also included unfolded neutron and gamma-ray spectra as a function of detector angle in broad incident neutron energy bins. Multigroup Monte Carlo calculations using the MORSE code and ENDF/B-IV nitrogen cross-section data were made to analyze all reported results. Comparisons of calculated and measured results indicate that no major deficiencies exist in the ENDF/B-IV gamma-ray production data, in contrast to the conclusions drawn from studies in previous years. Deficiencies, however, were found in the neutron data, primarily in the elastic and inelastic data above 9 MeV and in the elastic angular distribution data around 5 MeV.