NEUTRON-CAPTURE CROSS-SECTION OF O-18 AND ITS ASTROPHYSICAL IMPLICATIONS

The neutron capture rate on O-18 is of considerable interest in the in terpretation of nucleosynthesis in inhomogeneous big bang scenarios an d for stellar helium burning in massive red giant stars as well as AGE stars. We measured the reaction cross section of O-18(n,gamma)O-19 at the Forschungszentrum Karlsruhe with a fast cyclic neutron activation technique at laboratory neutron energies of 25, 129, 152, 250, and 37 0 keV. Direct capture and shell model calculations were performed to i nterpret the results as well as previous unpublished data. Contributio ns to the reaction cross section and to the new stellar reaction rate will be discussed.