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Please use this identifier to cite or link to this item: http://repository.iitr.ac.in/handle/123456789/27626
Title: First Measurement of the 64Ni(γ?,n)63Ni cross section
Authors: Dillmann I.
Faestermann T.
Korschinek G.
Lachner J.
Maiti, Moumita
Poutivtsev M.
Rugel G.
Walter S.
Käppeler F.
Erhard M.
Junghans A.R.
Nair C.
Schwengner R.
Wagner A.
Pignatari M.
Rauscher T.
Mengoni A.
Published in: Proceedings of Science
11th Symposium on Nuclei in the Cosmos, NIC 2010
Abstract: In the past 10 years new and more accurate stellar neutron capture cross section measurements have changed and improved the abundance predictions of the weak s process. Among other elements in the region between iron and strontium, most of the copper abundance observed today in the solar system distribution was produced by the s process in massive stars. However, experimental data for the stellar 63Ni(n,γ?)64Ni cross section are still missing, but is strongly required for a reliable prediction of the copper abundances. 63Ni (t1/2=101.2 a) is a branching point and also a bottleneck in the weak s process flow, and behaves differently during core He and shell C burning. During core He burning the reaction flow proceeds via β?-decay to 63Cu, and a change of the 63Ni(n,γ? )64Ni cross section would have no influence. However, this behavior changes at higher temperatures and neutron densities during the shell C burning phase. Under these conditions, a significant amount of the s process nucleosynthesis flow is passing through the channel 62Ni(n,γ?) 63Ni(n,γ?)64Ni. At present only theoretical estimates are available for the 63Ni(n,γ?)64Ni cross section. The corresponding uncertainty affects the production of 63Cu in present s process nucleosynthesis calculations and propagates to the abundances of the heavier species up to A=70. So far, experimental information is also missing for the inverse 64Ni(γ?,n) channel. We have measured for the first time the 64Ni(γ?,n) 63Ni cross section and also combined for the first time successfully the photoactivation technique with subsequent Accelerator Mass Spectrometry (AMS). The activations at the ELBE facility in Dresden-Rossendorf were followed by the 63Ni/64Ni determination with AMS at the MLL accelerator laboratory in Garching. First results indicate that theoretical predictions have overestimated this cross section up to now. If this also holds for the inverse channel 63Ni(n,γ?)64Ni, more 63Ni is accumulated during the high neutron density regime of the C shell that will contribute to the final abundance of 63Cu by radiogenic decay. In this case, also a lower s process efficiency is expected for the heavier species along the neutron capture path up to the Ga-Ge region. © Copyright owned by the author(s).
Citation: Proceedings of Science (2010)
URI: http://repository.iitr.ac.in/handle/123456789/27626
Issue Date: 2010
Keywords: Accelerator mass spectrometry
Behavior change
Branching points
Neutron capture
Neutron capture cross section
Neutron density
Photo activations
System distribution
Chemical elements
Copper
Forecasting
Germanium
Mass spectrometry
Neutrons
Nucleosynthesis
Stars
Nickel
ISSN: 18248039
Author Scopus IDs: 7801457599
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55925651100
13805228300
55975509900
8869211400
7003339028
8869212400
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8420846200
7005564711
56234924900
Author Affiliations: Dillmann, I., Physik-Department, Excellence Cluster Universe, D-85748 Garching, Germany, Karlsruhe Institute of Technology, Institut für Kernphysik, Campus Nord, D-76021 Karlsruhe, Germany, II. Physikalisches Institut, Justus-Liebig Universität Giessen, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
Faestermann, T., Physik-Department, Excellence Cluster Universe, D-85748 Garching, Germany
Korschinek, G., Physik-Department, Excellence Cluster Universe, D-85748 Garching, Germany
Lachner, J., Physik-Department, Excellence Cluster Universe, D-85748 Garching, Germany, Labor für Ionenstrahlphysik, ETH Zürich, Switzerland
Maiti, M., Physik-Department, Excellence Cluster Universe, D-85748 Garching, Germany, Saha Institute of Nuclear Physics, Chemical Sciences Division, 1/AF Bidhannagar, Kolkata, India
Poutivtsev, M., Physik-Department, Excellence Cluster Universe, D-85748 Garching, Germany
Rugel, G., Physik-Department, Excellence Cluster Universe, D-85748 Garching, Germany
Walter, S., Karlsruhe Institute of Technology, Institut für Kernphysik, Campus Nord, D-76021 Karlsruhe, Germany
Käppeler, F., Karlsruhe Institute of Technology, Institut für Kernphysik, Campus Nord, D-76021 Karlsruhe, Germany
Erhard, M., Institut für Strahlenphysik, Helmholtz-Zentrum Dresden-Rossendorf E.V., Bautzner Landstrasse 400, D-01328 Dresden, Germany, Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, D-38116 Braunschweig, Germany
Junghans, A.R., Institut für Strahlenphysik, Helmholtz-Zentrum Dresden-Rossendorf E.V., Bautzner Landstrasse 400, D-01328 Dresden, Germany
Nair, C., Institut für Strahlenphysik, Helmholtz-Zentrum Dresden-Rossendorf E.V., Bautzner Landstrasse 400, D-01328 Dresden, Germany, Argonne National Laboratory, United States
Schwengner, R., Institut für Strahlenphysik, Helmholtz-Zentrum Dresden-Rossendorf E.V., Bautzner Landstrasse 400, D-01328 Dresden, Germany
Wagner, A., Institut für Strahlenphysik, Helmholtz-Zentrum Dresden-Rossendorf E.V., Bautzner Landstrasse 400, D-01328 Dresden, Germany
Pignatari, M., Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556, United States, Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P5C2, Canada, TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T2A3, Canada
Rauscher, T., Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
Mengoni, A., ENEA, Bologna, Italy
Funding Details: 
Corresponding Author: Physik-Department, , D-85748 Garching, Germany
Appears in Collections:Conference Publications [PH]

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