1. Correlations between energy and $\gamma$-ray emission in $^{239}\mathrm{Pu}(n,\mathrm{f})$
- Author
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Giha, Nathan P., Marin, Stefano, Baker, James A., Hernandez, Isabel E., Kelly, Keegan J., Devlin, Matthew, O'Donnell, John M., Vogt, Ramona, Randrup, Jørgen, Talou, Patrick, Stetcu, Ionel, Lovell, Amy E., Litaize, Olivier, Serot, Olivier, Chebboubi, Abdelhazize, Wu, Ching-Yen, Clarke, Shaun D., and Pozzi, Sara A.
- Subjects
Nuclear Experiment - Abstract
We study $\gamma$-ray emission following $^{239}\mathrm{Pu}(n,\mathrm{f})$ over an incident neutron energy range of $2 < E_i < 40$ MeV. We present the first experimental evidence for positive correlations between the total angular momentum generated in fission and the excitation energy of the compound nucleus prior to fission. The $\gamma$-ray multiplicity increases linearly with incident energy below the 2\textsuperscript{nd}-chance fission threshold with a slope of $0.085 \pm 0.010$ MeV$^{-1}$. This linear trend appears to hold for the average excitation energy of the compound nucleus between $9 < \langle E_x \rangle < 19$ MeV. Most of the multiplicity increase comes from an enhancement around a $\gamma$-ray energy of 0.7 MeV, which we interpret as stretched quadrupole $\gamma$ rays that indicate an increase in total fission-fragment angular momentum with excitation energy., Comment: 9 pages, 5 figures
- Published
- 2022
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