Hauser-Feshbach fission fragment de-excitation with calculated macroscopic-microscopic mass yields

Abstract

The Hauser-Feshbach statistical model is applied to the de-excitation of primary fission fragments using input mass yields calculated with macroscopic-microscopic models of the potential energy surface. We test the sensitivity of the prompt fission observables to the input mass yields for two important reactions, ${}^{235}$U$(n_{\mathrm{th}},f)$ and ${}^{239}$Pu$(n_{\mathrm{th}},f)$, for which good experimental data exist. General traits of the mass yields, such as the location of the peaks and their widths, can impact both the prompt neutron and $\gamma$-ray multiplicities, as well as their spectra. Specifically, we use several mass yields to determine a linear correlation between the calculated prompt neutron multiplicity $\bar{\nu }$ and the average heavy-fragment mass $⟨A_h⟩$ of the input mass yields $\partial \bar{\nu }/\partial ⟨A_h⟩=\pm 0.1n/f/\mathrm{u}$. The mass peak width influences the correlation between the total kinetic energy of the fission fragments and the total number of prompt neutrons emitted ${\bar{\nu }}_T(\mathrm{TKE})$. Typical biases on prompt particle observables from using calculated mass yields instead of experimental ones are: $\delta \bar{\nu }=4\%$ for the average prompt neutron multiplicity, $\delta {\bar{M}}_{\gamma }=1\%$ for the average prompt $\gamma$-ray multiplicity, $\delta {\bar{\epsilon }}_n^{\mathrm{LAB}}=1\%$ for the average outgoing neutron energy, $\delta {\bar{\epsilon }}_{\gamma }=1\%$ for the average $\gamma$-ray energy, and $\delta ⟨\mathrm{TKE}⟩=0.4\%$ for the average total kinetic energy of the fission fragments.

arXiv comment12 pages, 8 figures, 2 tables

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Cited by in corpus (10)

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• Primary fission fragment mass yields across the chart of nuclides
• Nucleosynthesis and observation of the heaviest elements
• Microscopic Calculation of Fission Product Yields with Particle Number Projection
• Benchmark of the GEF model for fission-fragment yields over an enlarged range
• Connection of four-dimensional Langevin model and Hauser-Feshbach theory to describe statistical decay of fission fragments
• Nuclear ${\beta }^{-}$-decay with statistical de-excitation