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

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