Photodisintegration of p-process nuclei

The neutron deficient p-nuclei are shielded from the s- or r-process by stable isotopes. P-nuclei are likely to be formed in high temperature cosmic scenarios like exploding supernovae by photodisintegration reactions on heavy r- or s- seed nuclei. The lack of experimental information on energy-dependent cross sections especially for (gamma,p) and (gamma,gamma) reactions reduces the applicability of nucleosynthesis models. Using intense bremsstrahlung produced at the superconducting electron linear accelereator ELBE at Forschungszentrum Dresden-Rossendorf we investigated (gamma,n), (gamma,p) and (gamma,alpha) reactions for the medium-mass p-nuclei 92Mo and 144Sm, as well as (gamma,n) reactions for 100Mo and 154Sm by photo-activation. The lowest photoactivation yields have been measured in an underground laboratory. The photodisintegration of 197Au serves as a benchmark and it is compared to data measured previously with the positron annihilation technique.