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HK: Fachverband Physik der Hadronen und Kerne
HK 49: Nuclear Astrophysics IV
HK 49.3: Vortrag
Mittwoch, 13. März 2024, 18:15–18:30, HBR 14: HS 4
Towards direct measurements of astrophysical neutron capture rates in unstable nuclei — •Timm-Florian Pabst1, Abdallah Karaka1, Markus Schiffer1, Stefan Heinze1, Erik Strub2, and Dennis Mücher1 — 1University of Cologne, Institute of Nuclear Physics, Cologne, Germany — 2University of Cologne, Division of Nuclear Chemistry, Cologne, Germany
The intermediate neutron capture process (i process) is presumably taking place in AGB stars and is required to explain elemental abundances of certain CEMP stars. With most quantities along the i process being well constrained experimentally, neutron capture rates are among the largest unknowns in terms of the nuclear physics input. While indirect measurements suffer from higher uncertainties, direct measurements are hindered by the fact that many key nuclei along the i process are unstable.
In this talk we will discuss the possibilities for direct measurements of neutron capture cross sections for selected long-lived target nuclei, with the goal to constrain the astrophysical conditions of the i process. We discuss the status and first tests of a new beamline for the production of a high density secondary neutron beam at the CologneAMS 6MV tandetron. Cross sections will be measured via a new activation technique based on beta-decay electron detection. Our first physics case is the 137Cs(n,γ)138Cs cross section with the goal to shed light into understanding the observed Lanthanum and Barium abundances in AGB stars.
Keywords: neutron capture; cross section; i-process; direct measurements