Investigating the Ag-109(p, gamma) Cd-110 reaction and its underlying nuclear physics

Background: The nucleosynthesis of neutron-deficient p nuclei remains an unsolved puzzle in nuclear astrophysics. Most likely, huge networks containing hundreds of nuclear reactions are responsible for the creation of this group of nuclei. In reality, many of the relevant reaction rates cannot be studied experimentally but need to be estimated using global and robust theoretical approaches. The underlying nuclear physics that enters these calculations is often still not constrained well enough, especially for nuclei further off the valley of stability. Purpose: Here, we complete the systematic measurement of radiative proton-capture reactions on stable Ag isotopes. The results will be used to test existing theoretical models and are crucial to constrain underlying nuclear physics properties. For this purpose, total cross sections of the Ag-109(p,gamma) Cd-110 reaction have been measured at proton energies between 2.5 and 5.0 MeV. Method: The cross-section measurements have been carried out by means of in-beam gamma-ray spectroscopy and the observation of all ground-state transitions in Cd-110. In general, the total cross sections depend strongly on the gamma-ray strength function (gamma-SF) and the nuclear level density (NLD). While the former one is taken from the systematics in other even-even Cd isotopes, the NLD has been constrained by renormalizing microscopic, tabulated values onto the low-lying cumulative number of levels. Results: For the first time, Ag-109 (p, gamma) Cd-110 reaction cross sections have been reported over a wide range of beam energies. The total cross-section results are in good agreement with a rather limited, formerly published dataset. A convincing agreement with recent Hauser-Feshbach calculations is received when using existing descriptions for the gamma-SF and a renormalized, microscopic NLD model. Conclusion: The measured cross sections confirmed the reliability of existing theoretical models used in Hauser-Feshbach statistical model calculations. Coherent results are obtained for the statistical nuclear physics properties in the even-even Cd isotopes as well as for the derived experimental cross sections