Quasi-differential neutron scattering from 238U from 0.5 to 20Â MeV

The Rensselaer Polytechnic Institute Linear Accelerator was used to produce a pulsed neutron beam that was incident on a 238U scattering sample 30 m from the source. Eight liquid scintillator (EJ-301) proton recoil fast neutron detectors located at several angles surrounding the sample were positioned at a distance 0.5 m. Neutrons resulting from elastic scattering, inelastic scattering, and fission reactions were recorded as a function of time-of-flight. Pulse shape analysis including a new gamma misclassification correction was used to reduce erroneous counts from gamma events produced from fission and inelastic scattering reactions. The experimental data were simulated using an improved model of the Rensselaer Polytechnic Institute neutron scattering system that included individual detector efficiencies and neutron flux shape. The experimental data were compared with several evaluated nuclear data libraries using a figure-of-merit. Overall, the JENDL-4.0 evaluation provided the best agreement with the 238U experimental data. Furthermore, the Rensselaer Polytechnic Institute scattering model was used to constrain uncertainties that allowed for improvements to a new 238U evaluation.