Speaker
Description
Improved measurements of $^{238}U(n,n'\gamma)$ cross-sections are needed to refine nuclear data evaluations used for fast reactors, stockpile stewardship, and nuclear astrophysics. The preliminary results of an experiment to measure neutron inelastic scattering on a natural uranium target will be presented. A 14 MeV deuteron beam was used to create a pulsed broad spectrum neutron beam via thick target deuteron breakup on carbon at the 88 Inch Cyclotron at Lawrence Berkeley National Laboratory. The outgoing gammas and neutrons were measured simultaneously using the Gamma Energy Neutron Energy Spectrometer for Inelastic Scattering (GENESIS). GENESIS is equipped with high purity germanium detectors and liquid organic scintillators that are capable of particle discrimination to isolate neutrons. Together they allow for high-resolution correlated neutron-gamma measurements to be made. The beam's pulse period leads to frame overlap of consecutive pulses where multiple neutron energies impinge on the target at the same time. This makes observations of $\gamma$ yields a convolution over multiple neutron energies. To resolve this, a reaction model code is coupled directly to our measured data through a modeled response matrix to allow for prediction of measured quantities. The reaction modeling parameters are then optimized using $\chi^2$ minimization to obtain a best fit of the reaction model inputs which include level density, gamma strength, and neutron optical model parameters. The measurements and modeling results will be presented as well as future work being done on the GENESIS array to further study fission in $^{238}U$.