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Title: Total absorption γ -ray spectroscopy of the β -delayed neutron emitters Br 87 , Br 88 , and Rb 94

In this paper, we investigate the decay of 87,88Br and 94Rb using total absorption γ-ray spectroscopy. These important fission products are β-delayed neutron emitters. Our data show considerable βγ intensity, so far unobserved in high-resolution γ-ray spectroscopy, from states at high excitation energy. We also find significant differences with the β intensity that can be deduced from existing measurements of the β spectrum. We evaluate the impact of the present data on reactor decay heat using summation calculations. Although the effect is relatively small it helps to reduce the discrepancy between calculations and integral measurements of the photon component for 235U fission at cooling times in the range 1-100 s. We also use summation calculations to evaluate the impact of present data on reactor antineutrino spectra. We find a significant effect at antineutrino energies in the range of 5 to 9 MeV. In addition, we observe an unexpected strong probability for γ emission from neutron unbound states populated in the daughter nucleus. The γ branching is compared to Hauser-Feshbach calculations, which allow one to explain the large value for bromine isotopes as due to nuclear structure. However the branching for 94Rb, although much smaller, hints of the need to increasemore » the radiative width Γ γ by one order of magnitude. Finally, this increase in Γ γ would lead to a similar increase in the calculated (n, γ) cross section for this very neutron-rich nucleus with a potential impact on r process abundance calculations.« less
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  1. Univ. of Valencia (Spain). Inst. of Corpuscular Physics
  2. Univ. of Surrey, Guildford (United Kingdom). Dept. of Physics
  3. Univ. of Nantes (France). School of Mines. SUBATECH. CNRS/IN2P3
  4. Univ. of Jyvaskyla (Finland). Dept. of Physics
  5. Research Centre for Energy, Environment and Technology (CIEMAT), Madrid (Spain)
  6. Polytechnic Univ. of Catalonia, Barcelona (Spain)
  7. Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division
  8. Brookhaven National Lab. (BNL), Upton, NY (United States)
  9. Petersburg Nuclear Physics Inst., Gatchina (Russian Federation)
Publication Date:
Report Number(s):
Journal ID: ISSN 2469-9985
Grant/Contract Number:
SC0012704; AC02-06CH11357; SEV-2014-0398; FPA2008-06419; FPA2010-17142; FPA2011-24553; FPA2014-52823-C2-1-P; CPAN CSD-2007-00042; 213503; 605203
Accepted Manuscript
Journal Name:
Physical Review C
Additional Journal Information:
Journal Volume: 95; Journal Issue: 2; Journal ID: ISSN 2469-9985
American Physical Society (APS)
Research Org:
Brookhaven National Lab. (BNL), Upton, NY (United States); Argonne National Lab. (ANL), Argonne, IL (United States); Univ. of Valencia (Spain); Univ. of Surrey, Guildford (United Kingdom); Univ. of Nantes (France); Univ. of Jyvaskyla (Finland)
Sponsoring Org:
USDOE Office of Science (SC); Ministry of Economy, Industry and Competitiveness (MINECO) (Spain); Academy of Finland; Engineering and Physical Sciences Research Council (EPSRC); Science and Technology Facilities Council (STFC) (United Kingdom); European Commission (EC)
Contributing Orgs:
Research Centre for Energy, Environment and Technology (CIEMAT), Madrid (Spain); Polytechnic Univ. of Catalonia, Barcelona (Spain); Petersburg Nuclear Physics Inst., Gatchina (Russian Federation)
Country of Publication:
United States
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1344595