# 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 _{th}, f) and ^{239}Pu (n _{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 γ-ray multiplicities, as well as their spectra. Specifically, we use several mass yields to determine a linear correlation between the calculated prompt neutron multiplicity $$\bar{v}$$ and the average heavy-fragment mass $$\langle$$A _{h}$$\rangle$$ of the input mass yields ∂$$\bar{v}$$/∂ $$\langle$$A _{h}$$\rangle$$ = ± 0.1 (n / f )/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, $$\bar{v}_T$$ ( TKE ) . Finally, typical biases on prompt particle observables from using calculated mass yields instead of experimental ones are δ$$\bar{v}$$ = 4 % for the average prompt neutron multiplicity, δ$$\overline{M}_γ$$ = 1% for the average prompt γ-ray multiplicity, δ$$\bar{ε}$$ $$LAB\atop{n}$$ = 1 % for the average outgoing neutron energy, δ$$\bar{ε}_γ$$ = 1 % for the average γ-ray energy, and δ $$\langle$$TKE$$\rangle$$ = 0.4 % for the average total kinetic energy of the fission fragments.

- Authors:

- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

- Publication Date:

- Research Org.:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

- Sponsoring Org.:
- USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation (NA-20)

- OSTI Identifier:
- 1440483

- Alternate Identifier(s):
- OSTI ID: 1426328

- Report Number(s):
- LA-UR-17-31000

Journal ID: ISSN 2469-9985; PRVCAN; TRN: US1900748

- Grant/Contract Number:
- AC52-06NA25396

- Resource Type:
- Journal Article: Accepted Manuscript

- Journal Name:
- Physical Review C

- Additional Journal Information:
- Journal Volume: 97; Journal Issue: 3; Journal ID: ISSN 2469-9985

- Publisher:
- American Physical Society (APS)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; Atomic and Nuclear Physics

### Citation Formats

```
Jaffke, Patrick John, Talou, Patrick, Sierk, Arnold John, and Moller, Peter.
```*Hauser-Feshbach fission fragment de-excitation with calculated macroscopic-microscopic mass yields*. United States: N. p., 2018.
Web. doi:10.1103/PhysRevC.97.034608.

```
Jaffke, Patrick John, Talou, Patrick, Sierk, Arnold John, & Moller, Peter.
```*Hauser-Feshbach fission fragment de-excitation with calculated macroscopic-microscopic mass yields*. United States. doi:10.1103/PhysRevC.97.034608.

```
Jaffke, Patrick John, Talou, Patrick, Sierk, Arnold John, and Moller, Peter. Thu .
"Hauser-Feshbach fission fragment de-excitation with calculated macroscopic-microscopic mass yields". United States. doi:10.1103/PhysRevC.97.034608. https://www.osti.gov/servlets/purl/1440483.
```

```
@article{osti_1440483,
```

title = {Hauser-Feshbach fission fragment de-excitation with calculated macroscopic-microscopic mass yields},

author = {Jaffke, Patrick John and Talou, Patrick and Sierk, Arnold John and Moller, Peter},

abstractNote = {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, 235U (nth, f) and 239Pu (nth, 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 γ-ray multiplicities, as well as their spectra. Specifically, we use several mass yields to determine a linear correlation between the calculated prompt neutron multiplicity $\bar{v}$ and the average heavy-fragment mass $\langle$Ah$\rangle$ of the input mass yields ∂$\bar{v}$/∂ $\langle$Ah$\rangle$ = ± 0.1 (n / f )/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, $\bar{v}_T$ ( TKE ) . Finally, typical biases on prompt particle observables from using calculated mass yields instead of experimental ones are δ$\bar{v}$ = 4 % for the average prompt neutron multiplicity, δ$\overline{M}_γ$ = 1% for the average prompt γ-ray multiplicity, δ$\bar{ε}$ $LAB\atop{n}$ = 1 % for the average outgoing neutron energy, δ$\bar{ε}_γ$ = 1 % for the average γ-ray energy, and δ $\langle$TKE$\rangle$ = 0.4 % for the average total kinetic energy of the fission fragments.},

doi = {10.1103/PhysRevC.97.034608},

journal = {Physical Review C},

issn = {2469-9985},

number = 3,

volume = 97,

place = {United States},

year = {2018},

month = {3}

}

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