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Title: Anomalies in the Charge Yields of Fission Fragments from the U ( n , f ) 238 Reaction

Fast-neutron-induced fission of 238U at an energy just above the fission threshold is studied with a novel technique which involves the coupling of a high-efficiency γ-ray spectrometer (MINIBALL) to an inverse-kinematics neutron source (LICORNE) to extract charge yields of fission fragments via γ-γ coincidence spectroscopy. Experimental data and fission models are compared and found to be in reasonable agreement for many nuclei; however, significant discrepancies of up to 600% are observed, particularly for isotopes of Sn and Mo. This indicates that these models significantly overestimate the standard 1 fission mode and suggests that spherical shell effects in the nascent fission fragments are less important for low-energy fast-neutron-induced fission than for thermal neutron-induced fission. Finally, this has consequences for understanding and modeling the fission process, for experimental nuclear structure studies of the most neutron-rich nuclei, for future energy applications (e.g., Generation IV reactors which use fast-neutron spectra), and for the reactor antineutrino anomaly.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [5] ;  [6] ;  [7] ;  [2] ;  [8] ;  [1] ;  [8] ;  [9] ;  [8] ;  [10] ;  [11] ;  [8] ;  [8] more »;  [8] ;  [12] ;  [8] ;  [13] ;  [14] ;  [1] ;  [7] ;  [15] ;  [16] ;  [17] ;  [7] ;  [5] ;  [4] ;  [18] ;  [10] ;  [6] ;  [11] ;  [11] ;  [10] ;  [19] ;  [18] ;  [10] ;  [11] ;  [20] ;  [11] ;  [1] ;  [10] ;  [11] ;  [7] « less
  1. Univ. Paris-Sud, Orsay (France). Inst. de Physique Nucleaire
  2. European Commission, Karlsruhe (Germany). Joint Research Centre
  3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  4. Subatech/Ecole des Mines, Nantes (France)
  5. Univ. of Surrey, Guildford (United Kingdom). Dept. of Physics
  6. Katholieke Univ. Leuven, Leuven (Belgium). Inst. for Nuclear and Radiation Physics
  7. Univ. Paris-Saclay, Gif-sur-Yvette (France)
  8. Centre National de la Recherche Scientifique (CNRS), Orsay (France). Inst. National de Physique Nucleaire et de Physique des Particules (IN2P3), Centre de Sciences Nucleaires et de Sciences de la Matiere (CSNSM)
  9. National Inst. of Nuclear Physics (INFN), Legnaro (Italy). National Lab. of Legnaro (INFN-LNL)
  10. Inst. fur Kernphysik, Koln (Deutschland)
  11. Univ. of Oslo (Norway). Dept. of Physics
  12. National Physical Lab., Middlesex (United Kingdom)
  13. Ludwig Maximilian Univ., Munich (Germany)
  14. Alternative Energies and Atomic Energy Commission (CEA), Arpajon (France)
  15. Centre d'Etudes Nucleaires de Bordeaux-Gradignan, Gradignan (France)
  16. Extreme Light Infrastructure-Nuclear Physics (ELI-NP), Bucharest-Magurele (Romania)
  17. European Commission, Geel (Belgium). Joint Research Centre
  18. Univ. of Surrey, Guildford (United Kingdom). Dept. of Physics; National Physical Lab., Middlesex (United Kingdom)
  19. Alternative Energies and Atomic Energy Commission (CEA), Cadarache (France)
  20. Univ. of Manchester (United Kingdom). Dept. of Physics
Publication Date:
Report Number(s):
LLNL-JRNL-737167
Journal ID: ISSN 0031-9007; PRLTAO; TRN: US1702815
Grant/Contract Number:
AC52-07NA27344; 05P15PKCIA; 222287
Type:
Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 118; Journal Issue: 22; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society (APS)
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE; Research Council of Norway; Science and Technology Facilities Council (STFC), UK
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS
OSTI Identifier:
1378544