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HK: Fachverband Physik der Hadronen und Kerne

HK 21: Kern- und Teilchen-Astrophysik

HK 21.4: Vortrag

Dienstag, 13. März 2007, 17:45–18:00, E

The (n,n’) cross section of ¹⁸⁷Os at 30 keV — •Marita Mosconi¹, Michael Heil¹, Franz Käppeler¹, Alberto Mengoni², and Ralf Plag¹ — ¹Forschungszentrum Karlsruhe, Karlsruhe, Germany — ²International Atomic Energy Agency, Vienna, Austria

The inelastic neutron scattering cross section of ¹⁸⁷Os for the first excited level (9.75 keV above the ground state) is important for evaluating the age of the universe via the Re/Os cosmochronometer. This information is required for calculating the competition between neutron capture and scattering under stellar conditions. The ⁷Li(p,n)⁷Be reaction at threshold has been used for producing 30 keV neutrons with less than 10 keV FWHM. Inelastic scattering events were detected by three ⁶Li glass detectors at 90, 120 and 270 degree with respect to the neutron beam. The measurement has been performed with isotopically enriched ¹⁸⁷Os and ¹⁸⁸Os samples. Detailed GEANT simulations of the full experiment setup were employed for the determination of various corrections. The results are compared to previous data and to theoretical predictions.