Measurement of the neutron-induced capture-to-fission cross section ratio in U233 at LANSCE

The neutron-induced capture-to-fission cross section ratio of $^{233}\mathrm{U}$ has been measured at the Los Alamos Neutron Science Center at Los Alamos National Laboratory in the energy range from 0.7 eV to 250 keV. The detector setup combines the Detector for Advanced Neutron Capture Experiments (DANCE) to measure $\ensuremath{\gamma}$ rays generated from both capture and fission reactions, and the neutron detector array at DANCE to measure fission neutrons. This is the first measurement of the capture-to-fission ratio between 2 and 30 keV. The evaluations are in good agreement with the results in the resolved resonance region. In both the unresolved resonance region and the fast neutron region, a lower capture-to-fission ratio is obtained in this work from 10 to 150 keV compared to current evaluations, while good agreement with the experimental data and the evaluations is found above 150 keV. Statistical model calculations were performed to compare with the experimental data. Significantly reduced $\ensuremath{\langle}{\mathrm{\ensuremath{\Gamma}}}_{\ensuremath{\gamma}}\ensuremath{\rangle}$ was required to reproduce the measured data.