How important is the Family? : Alpha nuclear potentials and p-process nucleosynthesis

Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike LicenceIn this work we present the results from the analysis of the experimentally measured angular distributions of the reaction 106Cd(α , α )106 Cd at several different energies around the Coulomb barrier. The difficulties that arise in the study of 106Cd-α -nuclear potential and the so called Family Problem are addressed in this work

Investigation of proton-induced reactions on Germanium isotopes

The cross sections of the Ge-70(p,gamma)As-71 and Ge-76(p, n)As-76 reactions have been measured in the energy range relevant for the astrophysical p-process (1.6-4.4 MeV). The proton beam was provided by the Van de Graaff and cyclotron accelerators of ATOMKI. The cross section was determined with the activation method by measuring the yield of the emitted gamma-radiation following the beta-decay of the reaction products. Experimental details and preliminary results are presented

Astrophysical S-factor for α-capture of ¹¹³In in the p-process energy range

The cross sections of In-113(alpha, gamma)Sb-117 and In-113(alpha,n)Sb-116 reactions have been measured using the activation method. The experiments were carried out at the ATOMKI cyclotron accelerator in the center of mass energy range from 8.7 to 13.7 MeV. Astrophysical S-factors have been calculated, and preliminary results are compared With statistical model predictions

Activation method combined with characteristic X-ray counting : A possibility to measure (alpha, gamma) cross sections on heavy p-nuclei

For an improved modeling of the astrophysical nucleosynthesis of p-nuclei, low energy cross section data of alpha-induced reactions on heavy isotopes are needed. Technical difficulties hamper the experimental determination of these cross sections, therefore the relevant experimental data are almost completely missing. Here we present a new method for the cross section measurements, the activation technique based on the detection of characteristic X-ray radiation. The feasibility of the method is illustrated through the measurement of the Tm-169(alpha, gamma)Lu-173 and Tm-169(alpha, n)Lu-172 reaction cross sections. Despite the relatively long half-life of the reaction products (T-1/2 = 500 and 6.7 days, respectively) it was possible to measure the cross section of the Tm-169(alpha, gamma)Lu-173 reaction between E-c.m. = 13.16 and 17.08 MeV. The Tm-169(alpha, n)Lu-172 reaction cross section was derived from close above the threshold up to E-c.m.. = 17.08 MeV. Details of the new method and the experimental results are presented. (C) 2011 Elsevier B.V. All rights reserved.Peer reviewe

Astrophysical S-factor for alpha-Capture of (113)In in the p-Process Energy Range

The cross sections of (113)In(alpha, gamma)(117)Sb and (113)In(alpha,n)(116)Sb reactions have been measured using the activation method. The experiments were carried out at the ATOMKI cyclotron accelerator in the center of mass energy range from 8.7 to 13.7 MeV. Astrophysical S-factors have been calculated, and preliminary results are compared With statistical model predictions

Alpha-induced reaction cross section measurements on Eu-151 for the astrophysical gamma-process

In order to extend the experimental database relevant for the astrophysical gamma-process towards the unexplored heavier mass region, the cross sections of the Eu-151(alpha, gamma)Tb-155 and Eu-151 (alpha, n)Tb-154 reactions have been measured at low energies between 12 and 17 MeV using the activation technique. The results are compared with the predictions of statistical model calculations and it is found that the calculations overestimate the cross sections by about a factor of 2. A sensitivity analysis shows that this discrepancy is caused by the inadequate description of the alpha+nucleus channel. A factor of 2 reduction of the reaction rate of Eu-151(alpha, gamma)Tb-155 in gamma-process network calculations with respect to theoretical rates using the optical potential by McFadden and Satchler (1966 Nucl. Phys. 84 177) is recommended