AMS Applications in Nuclear Astrophysics: New Results for C-13(n,gamma)C-14 and N-14(n,p)C-14

Autor(en)

Anton Wallner, Kathrin Buczak, I Dillmann, Jenny Feige, Franz Käppeler, Gunther Korschinek, Claudia Lederer, Alberto Mengoni, Ulrich Ott, Michael Paul, Gabriele Schätzel, Peter Steier, H. P. Trautvetter

Abstrakt

The technique of accelerator mass spectrometry (AMS) offers a complementary tool for studying long-lived radionuclides in nuclear astrophysics: (1) as a tool for investigating nucleosynthesis in the laboratory; and (2) via a direct search of live long-lived radionuclides in terrestrial archives as signatures of recent nearby supernova-events. A key ingredient to our understanding of nucleosynthesis is accurate cross-section data. AMS was applied for measurements of the neutron-induced cross sections C-13(n,gamma)C and N-14(n,p), both leading to the long-lived radionuclide C-14. Solid samples were irradiated at Karlsruhe Institute of Technology with neutrons closely resembling a Maxwell-Boltzmann distribution for kT=25 keV, and with neutrons of energies between 123 and 178 keV. After neutron activation the amount of C-14 nuclides in the samples was measured by AMS at the VERA (Vienna Environmental Research Accelerator) facility. Both reactions, C-13(n,gamma)C-14 and N-14(n,p)C-14, act as neutron poisons in s-process nucleosynthesis. However, previous experimental data are discordant. The new data for both reactions tend to be slightly lower than previous measurements for the 25 keV Maxwell-Boltzmann energy distribution. For the higher neutron energies no previous data did exist for C-13(n,gamma), but model calculations indicated a strong resonance structure between 100 and 300 keV which is confirmed by our results. Very limited information is available for N-14(n,p) at these energies. Our new data at 123 and 178 keV suggest lower cross sections than expected from previous experiments and data evaluations.

Organisation(en)

Isotopenphysik

Externe Organisation(en)

Karlsruher Institut für Technologie, Technische Universität München, International Atomic Energy Agency (IAEA), Max-Planck-Institut für Chemie (Otto-Hahn-Institut), Hebrew University Jerusalem, Ruhr-Universität Bochum (RUB)

Journal

Publications of the Astronomical Society of Australia

Band

29

Seiten

115-120

Anzahl der Seiten

6

ISSN

1323-3580

DOI

https://doi.org/10.1071/AS11069

Publikationsdatum

2012

Peer-reviewed

Ja

ÖFOS 2012

1030 Physik, Astronomie, 103004 Astrophysik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/32899886-a26d-4564-8efc-b98a6b5d6162