Development of a Methodology for Analysis of the Fe-56 ENDF-B/VI Cross Sections with a Time-of-Flight Experiment

This paper discusses a methodology developed for analysis of a time-of-flight (TOF) experiment performed for examination of iron cross sections. The methodology combines measurements from several experimental setups and Monte Carlo simulations. Neutron TOF spectra are obtained via the spherical shell transmission method with iron shells of two thicknesses and using both 15N(p,n) and D(d,n) neutron source interactions at various beam angles. Experimental data were used to determine a source distribution for Monte Carlo Simulations. Comparison of experiments and calculations identified discrepancies over several energy ranges that may be attributed to inaccuracies in the Fe-56 inelastic scattering cross-section. To further investigate this issue, the Fe-56 scattering cross sections were adjusted, and used in the Monte Carlo simulations. The results of these simulations demonstrate that the adjusted cross-sections result in significant reductions (as large as ∼40%) in the discrepancies between experimental and calculated spectra The adjusted cross-sections were collapsed into a multigroup form and applied to a 1-D Pressure Vessel fluence calculation, which resulted in noticeable effects. Further studies are warranted