Astrophysical reaction rates for Ni58,60(n,γ) from new neutron capture cross section measurements

New neutron capture cross sections of Ni58,60 were measured in the energy range from 100 eV to 600 keV using the Oak Ridge Electron Linear Accelerator. The combination of these new neutron capture data with previous transmission data allowed a resonance analysis up to 900 keV using R-matrix theory. The theoretically determined direct capture cross sections were included in the analyses. From these resonance parameters and the direct capture contribution, new (n,γ) astrophysical reaction rates were determined over the entire energy range needed by the latest stellar models describing the so-called weak s process.