skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Analysis of a neutron scattering and gamma-ray production integral experiment on oxygen for neutron energies from 1 to 15 MeV

Technical Report ·
DOI:https://doi.org/10.2172/7346628· OSTI ID:7346628

Monte Carlo calculations were performed to analyze an integral experiment on a liquid oxygen sample to determine the adequacy of the neutron scattering and gamma-ray production data for oxygen. The experimental results included energy- and angular-dependent NE-213 detector count rates and secondary pulse-height spectra for scattered neutrons and gamma rays. The sample was a spherical dewar of liquid oxygen pulsed with a 1- to 20-MeV neutron source. Pulse-height data were unfolded to generate secondary neutron and gamma-ray production spectra as a function of angle in broad incident neutron energy bins. Analysis of all the reported data was based on multigroup Monte Carlo calculations using the MORSE code. Results indicate that the current ENDF/B-IV neutron and gamma-ray production data for oxygen above 1 MeV appear to be in good order. The only major discrepancy uncovered was related to neutron scattering and gamma-ray production from first level inelastic scattering interactions. Calculated results for the production of 6-MeV gamma rays from the 6-MeV first inelastic level in oxygen appear to be low by around 50 percent at energies above the inelastic threshold. Likewise, calculated secondary neutron spectra for incident neutron energies above 6 MeV are uniformly low at energies corresponding to neutrons having had first level inelastic scattering events in oxygen. Additional deficiencies in the oxygen cross-section data are indicated for inelastic scattering from the cluster of discrete levels in the 12-13 MeV range and for elastic scattering at very small angles at energies above 2 MeV. The size of the inelastic discrepancies are larger than the 20-30 percent order of error indicated for these cross sections in the ENDF/B-IV uncertainty files for oxygen.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
DOE Contract Number:
W-7405-ENG-26; SUB-TAS-PE083
OSTI ID:
7346628
Report Number(s):
ORNL/TM-5535; TRN: 77-000871
Country of Publication:
United States
Language:
English