Speaker
Description
Neutron-induced cross sections on fissile nuclei such as $^{239}$Pu are important for defense and energy applications, as well as for basic science. The quality of these values rely on two basic pillars: a) the availability of high-quality, curated experimental data. Within this context, it is essential to constantly update the existing database with the new experiments carried out in facilities where neutron beams are available. b) the implementation and fine-tuning of theoretical models, ensuring the consistency of the variety of observables among themselves, as well as with our knowledge of the structure of the nuclei involved. Theory then provides energy-dependent cross sections that can be used in transport codes and reaction networks calculations, even for energies where experimental data might not be currently available. I present here the results obtained in the evaluation of $^{239}$Pu neutron-induced cross sections, for incident neutron energies 4 keV$ < E_n < 20$ MeV. We incorporate to the experimental database the recent measurement of the $^{239}$Pu($n,f$)/$^{235}$U($n,f$) cross section ratio, performed at the Los Alamos Neutron Science Center (LANSCE) with the NIFFTE collaboration's fission TPC. The reaction and decay processes are described within the Hauser-Feshbach statistical decay framework and the coupled-channels reaction formalism, implemented in the codes YAHFC and FRESCO, respectively.