Consideration of memory of spin and parity in the fissioning compound nucleus by applying the Hauser-Feshbach fission fragment decay model to photonuclear reactions

Abstract

Prompt and ${\hat{I}}^2$-delayed fission observables, such as the average number of prompt and delayed neutrons, the independent and cumulative fission product yields, and the prompt ${\hat{I}}^3$-ray energy spectra for the photonuclear reactions on ${}^{235,238}$U and ${}^{239}$Pu are calculated with the Hauser-Feshbach Fission Fragment Decay (HF${}^3$D) model and compared with available experimental data. In the analysis of neutron-induced fission reactions to the case of photo-induced fission, an excellent reproduction of the delayed neutron yields supports a traditional assumption that the photo-fission might be similar to the neutron-induced fission at the same excitation energies regardless of the spin and parity of the fissioning systems.