Cross section measurements related to the p-process nucleosynthesis for proton-induced reactions on 164Er isotope

Full text: Although the origin of the element abundances is mainly well understood, some significant uncertainties are still available. Moreover, In contrast to s- and r-process there are not much p-process study, even though its network calculations require at least 10000 reactions on about 1800 stable and unstable nuclei. Therefore, the calculations are based on statistical model or Hauser-Feshbach predictions, and the overall reliability of Hauser-Feshbach predictions in p-process simulations has been discussed. The measurements of the reaction cross sections relevant to the astrophysical p-process are crucial to test the theoretical reaction rates with experimental data. The total cross sections for the 164Er(p, γ)165Tm and 164Er(p,n)164Tm reactions have been measured in the effective center-of-mass energies respectively 3.91 MeV ≤ E ≤ 7.81 MeV and 5.86 MeV ≤ E ≤ 6.83 MeV, close to the astrophysically relevant energy range. The experiments were carried out by the activation method at the FN Tandem Accelerator of the University of Notre Dame Institute for Structure and Nuclear Astrophysics Laboratory (Indiana, USA). The activities were determined by offline detection of the decay gamma rays with a HPGe detector. The targets with the thicknesses between 187 μg/cm2 and 266 μg/cm2 were prepared by evaporation of 75.32 % isotopically enriched 164Er2O3 powder on Aluminum backing foils, and bombarded with proton beams of 350-600 nA. The obtained results for 164Er(p, γ)165Tm and 164Er(p,n)164Tm reaction cross sections have been compared with the predictions of Hauser-Feshbach statistical model calculations using the standard NON-SMOKER and default TALYS codes. The details of the measurements and the preliminary results will be presented in this work.