Experimental study of α-induced reactions on 113In for the astrophysical p process

Neutron deficient nuclei from 74Se - 196Hg are thought to be produced by gamma -induced reactions (gamma , n), (gamma , p), and (gamma , alpha) processes. The stacked foil activation method was used to measure the 113In(alpha, gamma ) reaction cross section at Elab = 8.29-17.78 MeV. 113In(alpha, n) reaction cross section was also measured at Elab = 9.80-17.78 MeV. 113In(alpha, gamma ) reaction cross section was measured for the first time at Elab = 8.29 +/- 0.76 MeV (a = 1.5 +/- 0.3 mu b). Vacuum evaporation technique was used for preparing the targets (60-85 mu g/cm2). Theoretical statistical model calculations were performed with different nuclear input parameters and compared with the experimental results. An appropriate alpha-optical potential has been identified from the (alpha, gamma ) and (alpha, n) fitting, which provides the major source of uncertainty in the statistical model calculations. The other nuclear input parameters, such as level density and gamma -ray strength function, were also constrained for theoretical calculations. 113In(alpha, gamma ) 117Sb and 117Sb(gamma , alpha) 113In reaction rates were calculated using best-fit input parameters.