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

TL;DR

This paper applies the Hauser-Feshbach Fission Fragment Decay model to photonuclear reactions on uranium and plutonium isotopes, successfully reproducing various fission observables and supporting assumptions about photo-fission similarities to neutron-induced fission.

Contribution

It introduces a detailed application of the HF3D model to photonuclear fission, incorporating memory effects of spin and parity, and compares results with experimental data.

Findings

Excellent reproduction of delayed neutron yields.

Supports similarity between photo-fission and neutron-induced fission.

Validates the HF3D model for photonuclear reactions.

Abstract

Prompt and $\beta$-delayed fission observables, such as the average number of prompt and delayed neutrons, the independent and cumulative fission product yields, and the prompt $\gamma$-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.