Cross-section measurements relevant for the astrophysical p process at the University of Cologne

Abstract

The astrophysical p process unites all processes that have been introduced to explain the abundance of a group of 30 to 35 neutron-deficient nuclei which are referred to as p nuclei. In general, these p processes include large networks of nuclear reactions and a complete understanding of the individual reaction rates is required to describe the abundance of the p nuclei qualitatively and quantitatively. In many cases the involved nuclear reactions are not accessible in the laboratory, either due to their low cross sections or because they involve unstable or exotic isotopes. For those purposes, the motivation of cross-section measurements performed at the University of Cologne is twofold: First, experimentally constrained reaction rates are of direct relevance for nucleosynthesis network calculations. And second, experimental cross-section values are required to test existing theoretical descriptions and to improve their predictive power. In this work, we present the experimental setups and methods that are used to measure nuclear cross-sections at very low sensitivities and we show a detailed overview of proton-and α-induced reactions that have been measured in Cologne in the last decade.