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Title: Late-time emission of prompt fission γ rays

Journal Article · · Physical Review C

The emission of prompt fission γ rays within a few nanoseconds to a few microseconds following the scission point is studied in the Hauser-Feshbach formalism applied to the deexcitation of primary excited fission fragments. Neutron and γ-ray evaporations from fully accelerated fission fragments are calculated in competition at each stage of the decay, and the role of isomers in the fission products, before β decay, is analyzed. The time evolution of the average total γ-ray energy, the average total γ-ray multiplicity, and the fragment-specific γ-ray spectra is presented in the case of neutron-induced fission reactions of 235U and 239Pu, as well as spontaneous fission of 252Cf. The production of specific isomeric states is calculated and compared to available experimental data. About 7% of all prompt fission γ rays are predicted to be emitted between 10 ns and 5 μs following fission, in the case of 235U and 239Pu(nth,f) reactions, and up to 3% in the case of 252Cf spontaneous fission. The cumulative average total γ-ray energy increases by 2% to 5% in the same time interval. Lastly, those results are shown to be robust against significant changes in the model input parameters.

Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation
Grant/Contract Number:
AC52-06NA25396
OSTI ID:
1343702
Alternate ID(s):
OSTI ID: 1337442
Report Number(s):
LA-UR-16-24045; PRVCAN; TRN: US1701102
Journal Information:
Physical Review C, Vol. 94, Issue 6; ISSN 2469-9985
Publisher:
APSCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 32 works
Citation information provided by
Web of Science

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Cited By (4)

Review on the progress in nuclear fission—experimental methods and theoretical descriptions journal September 2018
High resolution measurement of tagged two-neutron energy and angle correlations in Cf 252 (sf) journal July 2019
Correlated prompt fission data in transport simulations journal January 2018
Correlated Prompt Fission Data in Transport Simulations text January 2017

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