Systematic study of theα-optical potential via elastic scattering near theZ=50region forp-process nuclei

Production of proton-rich nuclei beyond iron in stars proceeds via the p process, i.e., a sequence of photodisintegration reactions, (γ ,n), (γ ,p), and (γ ,α) on heavy nuclei at temperatures of 2–3 × 109 K. The involved reaction rates are typically calculated with the statistical Hauser-Feshbach (HF) model. However, the HF model performs poorly in calculating the critical (γ ,α) rates due to the uncertainty of the alpha optical potentials applied. To test the reliability of the HF calculations and provide a systematic understanding of the α optical potential at energies of astrophysical interest, a series of precision α scattering measurements were carried out at the Notre Dame FN Tandem Accelerator. Specifically, 106Cd, 118Sn, and 120,124,126,128,130Te were studied at energies both below and above the Coulomb barrier. A new parametrization of the α optical potential was derived of the elastic scattering cross section data. The derived potential was applied for calculating the α-induced reaction cross sections on these nuclei using the HF approach. The results were compared to the corresponding experimental values obtained from previous activation measurements on Cd, Sn, and Te isotopes.