Speaker
Description
Surrogate reactions allow one to access to neutron-induced cross sections of short-lived nuclei, but require a consistent framework to relate measured deexcitation probabilities to neutron-induced observables. We present here the first application of the Monte Carlo R-matrix–extended formalism of O. Bouland (2019) to fissile 237-244Pu* isotopes. Neutron-induced cross sections and surrogate deexcitation probabilities are, for the first time, simultaneously analyzed using a unified set of nuclear-structure parameters.
Fission probabilities constrain fission-barrier heights. The theoretical framework is extended to model ‘giant’ resonance structures observed in the fission probabilities of some nuclides. A careful study of the impact of the uncertainties on nuclear parameters and on the populated compound system angular distribution has been carried out. The analysis reveals normalization issues in previous (t, p) fission probability data, particularly for ²⁴⁰Pu. Additionally, the only available low-energy neutron-induced fission cross section for ²³⁷Pu is found to be overestimated by 10–30%, impacting evaluated ²³⁶Pu cross sections below 50 keV.
| Session | Evaluation of Nuclear Data (theory, models, codes) |
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