Constraining astrophysical reaction rates: using the storage rings at FAIR/GSI

Ion optical calculations for a storage ringat the present GSI facility for direct proton-induced reactions relevant for different astrophysical processes are presented. As an example case, the 59 Cu(p, γ ) and 59 Cu(p, α ) reactions are shown. The branching of these two reactions is important in X-ray burst scenarios, since it determines the breakoutout of the major 56 Ni waiting point.