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

Makii, H. ; Nishio, K. ; Hirose, K. LU ; Orlandi, R. ; Léguillon, R. ; Ogawa, T. ; Soldner, T. ; Köster, U. ; Pollitt, A. and Hambsch, F. J. , et al. (2019) In Physical Review C 100(4).
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... (More)

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.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review C
volume
100
issue
4
article number
044610
publisher
American Physical Society
external identifiers
  • scopus:85073833389
ISSN
2469-9985
DOI
10.1103/PhysRevC.100.044610
language
English
LU publication?
yes
id
33633ca6-4ef1-4b97-8d42-976265056d75
date added to LUP
2019-11-04 12:18:21
date last changed
2022-04-18 18:35:24
@article{33633ca6-4ef1-4b97-8d42-976265056d75,
  abstract     = {{<p>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.</p>}},
  author       = {{Makii, H. and Nishio, K. and Hirose, K. and Orlandi, R. and Léguillon, R. and Ogawa, T. and Soldner, T. and Köster, U. and Pollitt, A. and Hambsch, F. J. and Tsekhanovich, I. and Aïche, M. and Czajkowski, S. and Mathieu, L. and Petrache, C. M. and Astier, A. and Guo, S. and Ohtsuki, T. and Sekimoto, S. and Takamiya, K. and Frost, R. J.W. and Kawano, T.}},
  issn         = {{2469-9985}},
  language     = {{eng}},
  number       = {{4}},
  publisher    = {{American Physical Society}},
  series       = {{Physical Review C}},
  title        = {{Effects of the nuclear structure of fission fragments on the high-energy prompt fission γ -ray spectrum in U 235 (nth,f)}},
  url          = {{http://dx.doi.org/10.1103/PhysRevC.100.044610}},
  doi          = {{10.1103/PhysRevC.100.044610}},
  volume       = {{100}},
  year         = {{2019}},
}