Test of statistical model cross section calculations for α-induced reactions on 107Ag at energies of astrophysical interest

Yalc cin, C. and Gyürky, G. and Rauscher, T. and Kiss, G. G. and Özkan, N. and Güray, R. T. and Halász, Z. and Szücs, T. and Fülöp, Z. and Farkas, J. and Korkulu, Z. and Somorjai, E.. (2015) Test of statistical model cross section calculations for α-induced reactions on 107Ag at energies of astrophysical interest. Physical Review C (PRC), 91 (3). 034610.

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Official URL: http://edoc.unibas.ch/41651/

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Astrophysical reaction rates, which are mostly derived from theoretical cross sections, are necessary input to nuclear reaction network simulations for studying the origin of p nuclei. Past experiments have found a considerable difference between theoretical and experimental cross sections in some cases, especially for (α,γ) reactions at low energy. Therefore, it is important to experimentally test theoretical cross section predictions at low, astrophysically relevant energies. The aim is to measure reaction cross sections of 107Ag(α,γ)111In and 107Ag(α,n)110In at low energies in order to extend the experimental database for astrophysical reactions involving α particles towards lower mass numbers. Reaction rate predictions are very sensitive to the optical model parameters and this introduces a large uncertainty into theoretical rates involving α particles at low energy. We have also used Hauser-Feshbach statistical model calculations to study the origin of possible discrepancies between prediction and data. An activation technique has been used to measure the reaction cross sections at effective center of mass energies between 7.79 MeV and 12.50 MeV. Isomeric and ground state cross sections of the (α,n) reaction were determined separately. The measured cross sections were found to be lower than theoretical predictions for the (α,γ) reaction. Varying the calculated averaged widths in the Hauser-Feshbach model, it became evident that the data for the (α,γ) and (α,n) reactions can only be simultaneously reproduced when rescaling the ratio of γ- to neutron width and using an energy-dependent imaginary part in the optical α+107Ag potential.
Faculties and Departments:05 Faculty of Science > Departement Physik > Former Organization Units Physics > Theoretische Physik Astrophysik (Thielemann)
UniBasel Contributors:Rauscher, Thomas
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:American Physical Society
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:30 Jun 2016 11:02
Deposited On:19 May 2016 07:13

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