Publikationen

Accelerator mass spectrometry measurements of the C-13(n,gamma)C-14 and N-14(n,p)C-14 cross sections

Autor(en)
A. Wallner, M. Bichler, K. Buczak, I. Dillmann, F. Kaeppeler, A. Karakas, C. Lederer, M. Lugaro, K. Mair, A. Mengoni, Gabriele Schätzel, P. Steier, H. P. Trautvetter
Abstrakt

The technique of accelerator mass spectrometry (AMS), offering a complementary tool for sensitive studies of key reactions in nuclear astrophysics, was applied for measurements of the C-13(n,gamma)C-14 and the N-14(n,p)C-14 cross sections, which act as a neutron poison in s-process nucleosynthesis. Solid samples were irradiated at Karlsruhe Institute of Technology with neutrons closely resembling a Maxwell-Boltzmann distribution for kT = 25 keV, and also at higher energies between En = 123 and 182 keV. After neutron irradiation the produced amount of C-14 in the samples was measured by AMS at the Vienna Environmental Research Accelerator (VERA) facility. For both reactions the present results provide important improvements compared to previous experimental data, which were strongly discordant in the astrophysically relevant energy range and missing for the comparably strong resonances above 100 keV. For C-13(n,gamma) we find a four times smaller cross section around kT = 25 keV than a previous measurement. For N-14(n,p), the present data suggest two times lower cross sections between 100 and 200 keV than had been obtained in previous experiments and data evaluations. The effect of the new stellar cross sections on the s process in low-mass asymptotic giant branch stars was studied for stellar models of 2 M-circle dot initial mass, and solar and 1/10th solar metallicity.

Organisation(en)
Isotopenphysik
Externe Organisation(en)
Australian National University, Technische Universität Wien, Karlsruher Institut für Technologie, Hungarian Academy of Sciences, European Organization for Nuclear Research (CERN), Ruhr-Universität Bochum (RUB)
Journal
Physical Review C
Band
93
Anzahl der Seiten
12
ISSN
0556-2813
DOI
https://doi.org/10.1103/PhysRevC.93.045803
Publikationsdatum
04-2016
Peer-reviewed
Ja
ÖFOS 2012
103004 Astrophysik, 103014 Kernphysik
Schlagwörter
Link zum Portal
https://ucris.univie.ac.at/portal/de/publications/accelerator-mass-spectrometry-measurements-of-the-c13ngammac14-and-n14npc14-cross-sections(086ad53e-ad9b-4933-b53a-be59a3058acb).html