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Görgen, A. (ORCID:0000000319169941)

Publications and source records attributed to Görgen, A. (ORCID:0000000319169941).

4 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Nuclear level density and γ -ray strength function of Ni 67 and the impact on the i process

Proton- γ coincidences from ( d , p ) reactions between a Ni 66 beam and a deuterated polyethylene target have been analyzed with the inverse-Oslo method to find the nuclear level density (NLD) and γ -ray strength function ( γ SF ) of Ni 67 . The Ni 66 ( n , γ ) capture cross section has been calculated using the Hauser-Feshbach model in using the measured NLD and γ SF as constraints. The results confirm that the Ni 66 ( n , γ ) reaction acts as a bottleneck when relying on one-zone nucleosynthesis calculations. However, the impact of this reaction is strongly dampened in multizone models of low-metallicity AGB stars experiencing i -process nucleosynthesis. Published by the American Physical Society 2025

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2023

First spectroscopic study of odd-odd Cu 78

Nuclei in the vicinity of 78 Ni are important benchmarks for nuclear structure, which can reveal changes in the shell structure far from stability. Spectroscopy of the odd-odd isotope 78 CU was performed for the first time in an experiment with the EURICA setup at the Radioactive Isotope Beam Factory at RIKEN Nishina Center. Excited states in the neutron-rich isotope were populated following the β decay of 78 Ni produced by in-flight fission and separated by the BigRIPS separator. A level scheme based on the analysis of $\gamma$-$\gamma$ coincidences is presented. Tentative spin and parity assignments were made when possible based on the β -decay feeding intensities and $\gamma$-decay properties of the excited states. Time correlations between β and $\gamma$ decay show clear indications of an isomeric state with a half-life of 3.8(4) ms. Large-scale Monte Carlo shell-model calculations were performed using the A3DA-m interaction and a valence space comprising the full f p shell and the 1⁢g 9/2 and 2⁢d 5/2 orbitals for both protons and neutrons. The comparison of the experimental results with the shell-model calculations allows interpreting the excited states in terms of spin multiplets arising from the proton-neutron interaction. In conclusion, the results provide further insight into the evolution of the proton single-particle orbitals as a function of neutron number, and quantitative information about the proton-neutron interaction outside the doubly magic 78 Ni core.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗