Effects of the nuclear structure of fission fragments on the high-energy prompt fission γ -ray spectrum in U 235 (nth,f)

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Abstract

The prompt fission γ-ray energy spectrum for cold-neutron-induced fission of U235 was measured in the energy range Eγ=0.8-20MeV, by gaining a factor of about 105 in statistics compared to the measurements performed so far. The spectrum exhibits local bump structures at Eγ≈4MeV and ≈6MeV, and also a broad one at ≈15MeV. In order to understand the origins of these bumps, the γ-ray spectra were calculated using a statistical Hauser-Feshbach model, taking into account the deexcitation of all the possible primary fission fragments. It is shown that the bump at ≈4MeV is created by the transitions between the discrete levels in the fragments around Sn132, and the bump at ≈6MeV mostly comes from the complementary light fragments. It is also indicated that a limited number of nuclides, which have high-spin states at low excitation energies, can contribute to the bump structure around Eγ≈15MeV, induced by the transition feeding into the low-lying high-spin states.

Detaljer

Författare
  • H. Makii
  • K. Nishio
  • K. Hirose
  • R. Orlandi
  • R. Léguillon
  • T. Ogawa
  • T. Soldner
  • U. Köster
  • A. Pollitt
  • F. J. Hambsch
  • I. Tsekhanovich
  • M. Aïche
  • S. Czajkowski
  • L. Mathieu
  • C. M. Petrache
  • A. Astier
  • S. Guo
  • T. Ohtsuki
  • S. Sekimoto
  • K. Takamiya
  • T. Kawano
Enheter & grupper
Externa organisationer
  • Japan Atomic Energy Agency
  • Advanced Science Research Center
  • Institut Laue Langevin
  • CEA/DSM-CNRS/IN2P3
  • Institute of Modern Physics, Chinese Academy of Sciences
  • University of the Chinese Academy of Sciences
  • Los Alamos National Laboratory
  • European Commission Joint Research Centre, Brussels
  • University of Paris-Sud
  • Kyoto University
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Subatomär fysik
Originalspråkengelska
Artikelnummer044610
TidskriftPhysical Review C
Volym100
Utgåva nummer4
StatusPublished - 2019
PublikationskategoriForskning
Peer review utfördJa