Sep 4 – 9, 2022
Europe/Zurich timezone

Direct reactions for nuclear astrophysics

Sep 6, 2022, 6:00 PM
61/1-201 - Pas perdus - Not a meeting room - (CERN)

61/1-201 - Pas perdus - Not a meeting room -


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Philipp Erbacher


The neutron activation technique is a well established method to measure neutron capture cross sections relevant for the s-process.The $^{7}$Li(p,n) reaction at E$_{p} = 1912\,$keV is often used as a neutron source since the energy distribution of the emitted neutrons closely resembles a Maxwell-Boltzmann spectrum of $k_{B}T = 25\,$keV mimicking the $^{22}$Ne($\alpha$,n) phase in TP-AGB stars. The weak s-process, which takes place in massive stars, can reach energies up to $k_{B}T = 90\,$keV. Neutron spectra corresponding to a Maxwell-Boltzmann distribution with $k_{B}T > 25\,$keV cannot be produced by the $^{7}$Li(p,n) reaction directly.
We developed a method to obtain quasi-Maxwellian neutron capture cross sections over a wide energy range by combining a set of spectrum average cross sections measured at six different proton energies and distances between the lithium target and the sample. The measured spectrum averaged cross section can be used to calculate the Maxwellian averaged cross-section from $k_{B}T = 25\,$keV to $k_{B}T = 90\,$keV. Over the last two years neutron capture cross sections on over 20 isotopes were measured at Goethe University Frankfurt using this method.
An overview of the current experimental method, challenges during data analysis and the first results are presented.

Primary author


Benjamin Brueckner (Goethe University Frankfurt (DE)) Sophia Florence Dellmann (Goethe University Frankfurt (DE)) Kathrin Gobel (Goethe University Frankfurt (DE)) Tanja Heftrich (Goethe University Frankfurt (DE)) Markus Reich (Goethe University Frankfurt (DE)) Cem Deniz Kurtulgil (Goethe University Frankfurt (DE)) Rene Reifarth (Goethe University Frankfurt (DE)) Meiko Volknandt (Goethe University Frankfurt (DE)) Mario Weigand (Goethe University Frankfurt (DE)) Alexandra Härth (Goethe University Frankfurt (DE)) Marcel Bennedik (Goethe University Frankfurt (DE)) Tabea Marie Kuttner (Goethe University Frankfurt (DE)) Janina Strahl (Goethe University Frankfurt (DE)) Ernest Ademi (Goethe University Frankfurt (DE))

Presentation materials