München 2006 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 26: Kern- und Teilchen-Astrophysik
HK 26.3: Vortrag
Dienstag, 21. März 2006, 17:30–17:45, E
Determination of stellar neutron cross sections with AMS — •I. Dillmann1,2, L. Coquard1, M. Heil1, T. Fästermann3, F. Käppeler1, K. Knie3, G. Korschinek3, W. Kutschera4, M. Poutivsev3, T. Rauscher2, G. Rugel3, F.-K. Thielemann2, and A. Wallner4 — 1Institut für Kernphysik, Forschungszentrum Karlsruhe, D-76021 Karlsruhe — 2Departement Physik und Astronomie, Universität Basel, CH-4056 Basel — 3Physik Departement E15, Technische Universität München, D-85748 Garching — 4Vienna Environmental Research Accelerator (VERA), Institut für Isotopenforschung und Kernphysik, Universität Wien, A-1090 Wien
The activation technique, which represents a well established tool for measurements of stellar neutron cross sections, has been combined with accelerator mass spectroscopy (AMS) for investigation of the stellar (n,γ) cross sections of 9Be, 40Ca, 58Ni, and 78Se at a thermal energy of kT= 25 keV. In all those cases, direct off-line counting of the produced activity with a HPGe is compromised by the long half-lives of the reactions products and the absence of suited γ-ray transitions.
The activation measurements were performed at the 3.7 MV Van de Graaff accelerator at Forschungszentrum Karlsruhe by irradiating natural samples in a quasi-stellar neutron spectrum of kT= 25 keV produced by the 7Li(p,n)7Be reaction. The AMS measurements were done at the Vienna Environmental Research Accelerator (9Be and 40Ca) and with the Gas-filled Analyzing Magnet System (GAMS) at the Munich MP Tandem accelerator (58Ni and 78Se).