Modeling the Emission of Prompt Fission γ Rays for Fundamental Physics and Applications

Prompt fission γ rays are calculated through Monte Carlo Hauser-Feshbach simulations of the decay of the primary fragments formed in the fission process. The CGMF code is used to track individual decay histories for specific initial fission fragment configu- rations, sampling emission probability distributions for both neutron and γ-ray emissions at each stage of the evaporation process. The prompt fission γ-ray spectrum averaged over all initial fission fragments is inferred as well as the average total number of emitted photons 〈Nγ〉. In addition, the probability distribution P〈Nγ〉 and individual spectra corresponding to specific fission frag- ments are computed. Results for several fission reactions of interest, 252Cf (sf), nth+239Pu, nth+235U, are presented and compared with recent experimental data.