Frankfurt 2014 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 54: Nukleare Astrophysik
HK 54.5: Talk
Friday, March 21, 2014, 12:15–12:30, HZ 4
Determining cross sections of the 187Re(α,n) reaction at astrophysically relevant energies — •Philipp Scholz1, Janis Endres1, Jan Mayer1, Lars Netterdon1, Anne Sauerwein2, and Andreas Zilges1 — 1Institute for Nuclear Physics, University of Cologne — 2Institute for Applied Physics, Goethe University Frankfurt
Network calculations of the γ process rely almost completely on theoretically predicted reaction rates in the scope of the Hauser-Feshbach statistical model. But especially the prediction of cross sections for (γ,α)-reactions at energies within or close to the astrophysically relevant energy window remains a problem due to the uncertainties in the basic α+nucleus optical-model potentials. Although experimental values far above the Coulomb-barrier are well reproduced, commonly used α-optical potentials often fail to describe the trend at center-of-mass energies comparable to those in astrophysical sites of the γ process. Improvements of the adopted optical-model potentials are hampered by the lack of experimental values at low energies. For the improvement of the experimental situation an α-induced reaction on the very heavy nucleus 187Re was investigated via the activation technique using the Cologne Clover Counting Setup. Cross sections at five energies close to the astrophysically relevant energy region could be measured amongst others applying the γγ-coincidence method. The experimental setup as well as recent results will be presented.
Partly supported by the DFG (ZI 510/5-1 and INST 216/544-1).