Low-energy enhancement and fluctuations of γ -ray strength functions in 56,57 Fe: test of the Brink–Axel hypothesis

Larsen, A. C.; Guttormsen, M.; Blasi, N.; Bracco, A.; Camera, F.; Campo, L. Crespo; Eriksen, T. K.; Gorgen, A.; Hagen, T. W.; Ingeberg, V. W.; Kheswa, B. V.; Leoni, S.; Midtbo, J. E.; Million, B.; Nyhus, H. T.; Renstrom, T.; Rose, S. J.; Ruud, I. E.; Siem, S.; Tornyi, T. G.; Tveten, G. M.; Voinov, A. V.; Wiedeking, M.; Zeiser, F.

doi:10.1088/1361-6471/aa644a

Title: Low-energy enhancement and fluctuations of γ -ray strength functions in ^56,57 Fe: test of the Brink–Axel hypothesis

Journal Article · Mon Apr 24 00:00:00 EDT 2017 · Journal of Physics. G, Nuclear and Particle Physics

DOI:https://doi.org/10.1088/1361-6471/aa644a· OSTI ID:1432356

Larsen, A. C. ^[1]; Guttormsen, M. ^[1]; Blasi, N. ^[2]; Bracco, A. ^[3]; Camera, F. ^[3]; Campo, L. Crespo ^[1]; Eriksen, T. K. ^[4]; Gorgen, A. ^[1]; Hagen, T. W. ^[1]; Ingeberg, V. W. ^[1]; Kheswa, B. V. ^[1]; Leoni, S. ^[3]; Midtbo, J. E. ^[1]; Million, B. ^[2]; Nyhus, H. T. ^[1]; Renstrom, T. ^[1]; Rose, S. J. ^[1]; Ruud, I. E. ^[1]; Siem, S. ^[1]; Tornyi, T. G. ^[1] more »

Univ. of Oslo (Norway). Dept. of Physics
National Inst. of Nuclear Physics (INFN), Milan (Italy)
National Inst. of Nuclear Physics (INFN), Milan (Italy); Univ. of Milan (Italy). Dept. of Physics
Univ. of Oslo (Norway). Dept. of Physics; Australian National Univ., Canberra, ACT (Australia). Dept. of Nuclear Physics
Ohio Univ., Athens, OH (United States). Dept. of Physics and Astronomy
iThemba LABS, Somerset West (South Africa)

Nuclear level densities and γ-ray strength functions of ^56,57Fe have been extracted from proton-γ coincidences. A low-energy enhancement in the γ-ray strength functions up to a factor of 30 over common theoretical E1 models is confirmed. Angular distributions of the low-energy enhancement in ⁵⁷Fe indicate its dipole nature, in agreement with findings for ⁵⁶Fe. The high statistics and the excellent energy resolution of the large-volume LaBr₃(Ce) detectors allowed for a thorough analysis of γ strength as function of excitation energy. Taking into account the presence of strong Porter–Thomas fluctuations, there is no indication of any significant excitation energy dependence in the γ-ray strength function, which is in support of the generalized Brink–Axel hypothesis.

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Research Organization:: Ohio Univ., Athens, OH (United States)

Sponsoring Organization:: USDOE National Nuclear Security Administration (NNSA); Univ. of Oslo (Norway); Research Council of Norway (NFR); European Research Council (ERC); National Research Foundation (NRF) (South Africa)

Grant/Contract Number:: NA0002905; 205528; 637686; 210007; 222287; 92789

OSTI ID:: 1432356

Journal Information:: Journal of Physics. G, Nuclear and Particle Physics, Vol. 44, Issue 6; ISSN 0954-3899

Publisher:: IOP PublishingCopyright Statement

Country of Publication:: United States

Language:: English

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Cited by: 20 works

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level density
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Title: Low-energy enhancement and fluctuations of γ -ray strength functions in 56,57 Fe: test of the Brink–Axel hypothesis

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Title: Low-energy enhancement and fluctuations of γ -ray strength functions in ^56,57 Fe: test of the Brink–Axel hypothesis