High precision113In(α,α)113In elastic scattering at energies near the Coulomb barrie

Abstract

Background:The γ process in supernova explosions is thought to explain the origin of proton-rich isotopes between Se and Hg, the so-called p nuclei. The majority of the reaction rates for γ process reaction network studies have to be predicted in Hauser-Feshbach statistical model calculations using global optical potential parametrizations. While the nucleon + nucleus optical potential is fairly well known, for the α + nucleus optical potential several different parametrizations exist and large deviations are found between the predictions calculated using different parameter sets. Purpose: By the measurement of elastic α-scattering angular distributions at energies around the Coulomb barrier a comprehensive test for the different global α + nucleus optical potential parameter sets is provided. Methods: Between 20 • and 175 • complete elastic alpha scattering angular distributions were measured on the 113 In p nucleus with high precision at E c.m. = 15.59 and 18.82 MeV. Results: The elastic scattering cross sections of the 113 In(α,α) 113 In reaction were measured for the first time at energies close to the astrophysically relevant energy region. The high precision experimental data were used to evaluate the predictions of the recent global and regional α + nucleus optical potentials. Parameters for a local α + nucleus optical potential were derived from the measured angular distributions. Conclusions: Predictions for the reaction cross sections of 113 In(α, γ ) 117 Sb and 113 In(α,n) 116 Sb at astrophysically relevant energies were given using the global and local optical potential parametrizations.

Cross-section measurements of radiative proton-capture reactions inCd112at energies of astrophysical interest

“…Many studies have focused on 113 In in the vicinity of γ-process nucleosynthesis energies, such as the 113,115 In(p, γ) 114,116 Sn reactions [29], the α elastic scattering [30], and the 113 In(α, γ) 117 Sb reactions [31]. Recently, Muhammed Shan et al [32] focused on protoninduced reactions in 113 In at energies ranging 8-22 MeV adding information to earlier investigations of the 112 Cd(p, n) 113 In reaction [33][34][35].…”

Unexpected properties of the33S(α,p)36Clreaction cross section at low energies

“…For many α-induced reaction cross sections at energies around the Coulomb barrier it is found that typical statistical model calculations are able to reproduce the experimental data above the Coulomb barrier whereas below the barrier experimental cross sections are significantly overestimated, see e.g. [2][3][4][5][6][7][8][9][10][11][12][13]. Similar to this general finding, the present 33 S(α,p) 36 Cl data [1] are roughly reproduced at the highest energy.…”

Cross-sections at sub-Coulomb energies: Full optical model versus barrier transmission for 40Ca + α

“…However, the importance of the tail of the imaginary potential at sub-Coulomb energies was not pointed out, see e.g. recent work [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59] on α-induced reactions at low energies from the last decade.…”