Experimental studies of optical potentials for p-process nucleosynthesis
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Beschreibung
The 35 neutron deficient nuclides known as the p nuclei are sysnthesized mainly in the so-called gamma process. Taking place in explosive supernova events, the existing seed distribution from prior nucleosynthesis is altered by photodisintegration reactions of the types (gamma,n), (gamma,p) and (gamma,alpha).
The bulk of reaction rates needed in network calculations of the gamma process are predicted by the Hauser-Feshbach Model. When using this theory, the largest uncertainties stem from the interaction between charged particles and nuclei described by optical model potentials.
An improvement of these potentials can be achieved by comparison to measured cross section data. However, because of the low energies of interest for nuclear astrophysics and the resulting low cross sections, suitable data are scarce.
This thesis extends the corresponding database by measurement of the reactions 165Ho(alpha,n), 166Er(alpha,n), 169Tm(p,n) and 175Lu(p,n) using the activation technique. While not particularly important for the gamma process, the selected (alpha,n) and (p,n) reactions exhibit nearly exclusive sensitivity to the alpha- or proton-nucleus potential, respectively. Therefore, the results presented here are well suited to test and improve the predictive power of currently available parameterizations of these potentials.
Autor*in
Jan Glorius