Informing (n,γ) reaction rates in weak r-process nucleosynthesis: ⁸⁰Ge(d,p) measurements at FRIB with GODDESS

Individual (n,g) rates become important during freeze out from the weak r-process, near Z=26-34 and N=50. Sensitivity studies [1] have identified specific isotopes, e.g., 80Ge, where unknown (n,g) rates could have significant impacts on final r-process abundance patterns. 80Ge is in reach at FRIB and an experiment was completed in April 2024 to inform the 80Ge(n,g) rate. The (d,pg) reaction was measured with an 80Ge beam using GODDESS [2] and the S800 at an energy of 45 MeV/u. The goal of this experiment is to inform the compound nucleus (n,g) cross sections via the Surrogate Reaction Method [3]. In combination with a previous measurement [4] at ~4 MeV/u, this measurement would also serve to constrain spectroscopic factors for bound states from which direct-semi-direct neutron capture cross sections would be determined. Preliminary results will be reported.

References:

[1] R. Surman et al. AIP Advances 4, 041008 (2014)

[2] S.D. Pain et al. Physics Procedia 90, 455 (2017)

[3] J.E. Escher et al., Rev. Mod. Phys. 84, 353 (2012)

[4] S. Ahn et al. Phys. Rev. C 100, 04613 (2019)