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Title: Excitation energy dependence of fragment-mass distributions from fission of 180,190Hg formed in fusion reactions of 36Ar + 144,154Sm

Mass distributions of fission fragments from the compound nuclei 180Hg and 190 Hg formed in fusion reactions 36Ar + 144 Smand 36Ar + 154Sm, respectively, were measured at initial excitation energies of E*( 180Hg) = 33-66 MeV and E*( 190Hg) = 48-71 MeV. In the fission of 180Hg, the mass spectra were well reproduced by assuming only an asymmetric-mass division, with most probable light and heavy fragment masses $$\overline{A}_L$$/ $$\overline{A}_H$$ = 79/101. The mass asymmetry for 180Hg agrees well with that obtained in the low-energy β +/EC-delayed fission of 180Tl, from our earlier ISOLDE(CERN) experiment. Fission of 190Hg is found to proceed in a similar way, delivering the mass asymmetry of $$\overline{A}_L$$/ $$\overline{A}_H$$ = 83/107, throughout the measured excitation energy range. The persistence as a function of excitation energy of the mass-asymmetric fission for both proton-rich Hg isotopes gives strong evidence for the survival of microscopic effects up to effective excitation energies of compound nuclei as high as 40 MeV. In conclusion, this behavior is different from fission of actinide nuclei and heavier mercury isotope 198Hg.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [1] ;  [1] ;  [8] ;  [9] ;  [9] ;  [1] ;  [1] ;  [10] ;  [11] ;  [12] ;  [13] ;  [14] ;  [15] more »;  [16] « less
  1. Japan Atomic Energy Agency (JAEA), Tokai (Japan). Advanced Science Research Center
  2. Japan Atomic Energy Agency (JAEA), Tokai (Japan). Advanced Science Research Center; Univ. of York (United Kingdom). Dept. of Physics; Univ. of the West of Scotland, Paisley, Renfrewshire (United Kingdom)
  3. Univ. of the West of Scotland, Paisley, Renfrewshire (United Kingdom)
  4. Johannes Gutenberg Univ., Mainz (Germany). Inst. of Nuclear Chemistry; Helmholtz Helmholtz Inst. Mainz, Mainz (Germany)
  5. Johannes Gutenberg Univ., Mainz (Germany). Inst. of Nuclear Chemistry; GSI-Helmholtz Centre for Heavy Ion Research, Darmstadt (Germany); Helmholtz Helmholtz Inst. Mainz, Mainz (Germany)
  6. Katholieke Univ. Leuven, Heverlee (Belgium). Inst. for Nuclear and Radiation Physics; Belgian Nuclear Research Center (SCK-CEN), Mol (Belgium)
  7. GSI-Helmholtz Centre for Heavy Ion Research, Darmstadt (Germany); Helmholtz Helmholtz Inst. Mainz, Mainz (Germany)
  8. Helmholtz Helmholtz Inst. Mainz, Mainz (Germany); GSI-Helmholtz Centre for Heavy Ion Research, Darmstadt (Germany)
  9. GSI-Helmholtz Centre for Heavy Ion Research, Darmstadt (Germany)
  10. Kyoto Univ., Osaka (Japan). Research Reactor Inst.
  11. Univ. of the West of Scotland, Paisley, Renfrewshire (United Kingdom); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  12. Joint Inst. for Nuclear Research (JINR), Dubna (Russian Federation). Flerov Lab. of Nuclear Reactions
  13. Univ. of Bordeaux (France)
  14. Katholieke Univ. Leuven, Heverlee (Belgium). Inst. for Nuclear and Radiation Physics
  15. Japan Atomic Energy Agency (JAEA), Tokai (Japan). Advanced Science Research Center; RIKEN, Wako (Japan). Nishina-Center
  16. China Inst. of Atomic Energy, Bejing (China)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Physics Letters. Section B
Additional Journal Information:
Journal Volume: 748; Journal Issue: C; Journal ID: ISSN 0370-2693
Publisher:
Elsevier
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE; Science and Technology Facilities Council (STFC) (United Kingdom); FWO-Vlaanderen, Belgium
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; (180; 190) Hg; Fusion-fission; Mass asymmetric fission
OSTI Identifier:
1339370