Previously published particle-γ coincidence data on the 64 Ni(p, p γ) 64 Ni and 64 Ni(d, pγ) 65 Ni reactions were further analyzed to study the statistical properties of γ decay in 64,65 Ni. To do so, the γ decay to the quasicontinuum region and discrete low-lying states was investigated at γ-ray energies of 2.0-9.6 and 1.6-6.1 MeV in 64 Ni and 65 Ni, respectively. In particular, the dependence of the γ-strength function with initial and final excitation energy was studied to test the validity of the generalized Brink-Axel hypothesis. Finally, the role of fluctuations in transition strengths was estimated as a function of γ-ray and excitation energy. The γ-strength function is consistent with the hypothesis of the independence of initial excitation energy, in accordance with the generalized Brink-Axel hypothesis. The results show that the γ decay to low-lying levels displays large fluctuations for low initial excitation energies.
Particle-γ coincidence data have been analyzed to obtain the nuclear level density and the γ -strength function of 64 Ni by means of the Oslo method. The level density found in this work is in very good agreement with known energy levels at low excitation energies as well as with data deduced from particle-evaporation measurements at excitation energies above E x ≈ 5.5 MeV. The experimental γ -strength function presents an enhancement at γ energies below E γ ≈ 3 MeV and possibly a resonancelike structure centered at E γ ≈ 9.2 MeV. The obtained nuclear level density and γ -strength function have been used to estimate the (n,γ ) cross section for the s-process branch-point nucleus 63 Ni, of particular interest for astrophysical calculations of elemental abundances.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.