Experimental constraints on the 73Zn (n, γ) 74Zn reaction rate.

Background: The recent observation of a neutron-star merger finally confirmed one astrophysical location of the rapid neutron-capture process (r-process). Evidence of the production of A < 140 nuclei was seen, but there is still little detailed information about how those lighter elements are produced in such an environment. Many of the questions surrounding the A ≈ 80 nuclei are likely to be answered only when the nuclear physics involved in the production of r-process nuclei is well understood. Neutron-capture reactions are an important component of the r-process, and neutron-capture cross sections of r-process nuclei, which are very neutron rich, have large uncertainties. Purpose: Indirectly determine the neutron-capture cross section and reaction rate of 73 Zn (n, γ) 74 Zn. Methods: The nuclear level density (NLD) and γ -ray strength function (γ SF) of 74 Zn were determined following a total absorption spectroscopy (TAS) experiment focused on the ß decay of 74 Cu into 74 Zn performed at the National Superconducting Cyclotron Laboratory. The NLD and γ SF were used as inputs in a Hauser-Feshbach statistical model to calculate the neutron-capture cross section and reaction rate. Results: The NLD and γ SF of 74 Zn were experimentally constrained for the first time using ß -delayed γ rays measured with TAS and the ß -Oslo method. The NLD and γ SF were then used to constrain the neutron-capture cross section and reaction rate for the 73 Zn (n, γ) 74 Zn reaction. Conclusions: The uncertainty in the neutron-capture cross section and reaction rate of 73 Zn (n, γ) 74 Zn calculated in TALYS was reduced to under a factor of 2 from a factor of 5 in the cross section and a factor of 11 in the reaction rate using the experimentally obtained NLD and γ SF. [ABSTRACT FROM AUTHOR]