Low-energy enhancement and fluctuations of γ-ray strength functions in 56, 57Fe: test of the Brink–Axel hypothesis. (24th April 2017)

• Record Type: Journal Article
• Authors: Larsen, A C; Guttormsen, M; Blasi, N; Bracco, A; Camera, F; Campo, L Crespo; Eriksen, T K; Görgen, A; Hagen, T W; Ingeberg, V W; Kheswa, B V; Leoni, S; Midtbø, J E; Million, B; Nyhus, H T; Renstrøm, T; Rose, S J; Ruud, I E; Siem, S; Tornyi, T G; Tveten, G M; Voinov, A V; Wiedeking, M; Zeiser, F
• Is Part Of: Journal of physics. Volume 44:Number 6(2017:Jun.)
• Publication Date: 2017-04-24
• Subjects: level density -- γ-strength function -- angular distributions -- Brink hypothesis -- iron; 21.10.Ma -- 21.10.-k -- 27.40.+z -- 25.20.Lj; Nuclear physics -- Periodicals; Particles (Nuclear physics) -- Periodicals; Physique nucléaire -- Périodiques; Particules (Physique nucléaire) -- Périodiques; Kernfysica; Elementaire deeltjes; 539.7
• DOI: 10.1088/1361-6471/aa644a
• Languages: English
• ISSNs: 0954-3899

Abstract

Abstract: Nuclear level densities and γ -ray strength functions of 56, 57 Fe 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 57 Fe indicate its dipole nature, in agreement with findings for 56 Fe. 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, in support of the generalized Brink–Axel hypothesis.