Under a joint collaboration between TUNL-LANL-LLNL, a set of absolute fission product yield measurements has been performed. The energy dependence of a number of cumulative fission product yields (FPY), for long lived (days-to-months) isotopes, have been measured using quasi-monoenergetic neutron beams for three actinide targets, 235U, 238U and 239Pu, between 0.5 and 14.8 MeV. The FPYs were measured by a combination of fission counting using specially designed dual-fission chambers and γ-ray counting. Each dual-fission chamber is a back-to-back ionization chamber encasing an activation target in the center with thin deposits of the same target isotope in each chamber. This method allows for the direct measurement of the total number of fissions in the activation target with no reference to the fission cross-section, thus reducing uncertainties. Reported are absolute cumulative fission product yields for incident neutron energies of 0.5, 1.37, 2.4, 3.6, 4.6 and 14.8 MeV. New data in the second chance fission region of 5.5 – 11 MeV are included to complete the measurements in the energy range of interest. These results are compared to previous measurements and theoretical estimates.
*This work was performed under the auspices of the U.S. Department of Energy by Triad National Security, LLC under contract DE- 89233218CNA000001.
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Publication:1) M.E. Gooden, et al., "Energy Dependence of Fission Product Yields from 235U, 238U and 239Pu for Incident Neutron Energies Between 0.5 and 14.8 MeV", Nuclear Data Sheets, 131 (2016) 319-356. 2)C. Bhatia, et al., "Exploratory study of fission product yields of neutron-induced fission of U235, U238, and Pu239at 8.9 MeV", Physical Review C 91, 064604 (2015). 3) C. Bhatia, et al., "Dual-fission chamber and neutron beam characterization for fission product yield measurements using monoenergetic neutrons", Nuclear Instruments and Methods in Physics Research A, 757 (2014) 7-19.
Presenters
Matthew E Gooden
Los Alamos National Laboratory
Authors
Matthew E Gooden
Los Alamos National Laboratory
Todd A Bredeweg
Los Alamos National Laboratory
Los Alamos Natl Lab
David Vieira
Los Alamos National Laboratory
Jerry B Wilhelmy
Los Alamos Natl Lab
Los Alamos National Laboratory
Anton P Tonchev
Lawrence Livermore National Laboratory
Lawrence Livermore Natl Lab
Jack A Silano
Lawrence Livermore National Laboratory
Mark A Stoyer
Lawrence Livermore National Laboratory
Lawrence Livermore Natl Lab
Anthony Paul Ramirez
Lawrence Livermore National Laboratory
Sean W Finch
Duke University
Werner Tornow
Department of Physics and Triangle Universities Nuclear Laboratory, Duke University, Durham, NC-27708-2308
