Measurement of elastic and inelastic neutron scattering in the energy range from 0.5 to 20 MeV

Abstract

Improvements were made to assess data collected by the Rensselaer Polytechnic Institute’s Neutron Scattering System. Reference pulses were developed to discriminate neutron from gamma-ray events. A technique to account for erroneously classified gamma-ray events was incorporated into the data analysis. New in-beam measurements were performed to characterize the energy-dependent neutron flux shape and to characterize each detector’s efficiency. These measurements were also crucial in the development of response functions needed to separate elastic and inelastic scattering. The new analysis methods and techniques were used on data collected from 238U and NatFe neutron time-of-flight scattering measurements. Results from the scattering measurements were used with an improved model of the Neutron Scattering System to benchmark nuclear evaluations. The model incorporated energy-dependent detector efficiencies, energy-dependent neutron flux shape, and a detailed geometric description. Based on the improved model and the new data analysis techniques a method to quantify systematic uncertainties was developed. The JENDL-4.0 evaluation had the best agreement with the TOF data for both the 238U and NatFe measurements.