Measurement of the (gamma,n) reaction rates of the nuclides Pt-190, Pt-192, and Pt-198 in the astrophysical gamma process

The nucleosynthesis of heavy neutron-deficient nuclei in a stellar photon bath at the temperatures relevant for the astrophysical gamma process was investigated. In order to derive (gamma ,n) cross sections and reaction rates, the stellar photon bath was simulated by the superposition of several bremsstrahlung spectra with different endpoint energies. As a first test for this method, the (gamma ,n) reaction rates of the platinum isotopes Pt-190, Pt-192, and Pt-198 were derived. The results are compared to other experimental data and theoretical calculations.