Sub-barrier fusion in the 37Cl + 130Te system

Abstract

Background: In heavy-ion induced reactions, the sub-barrier fusion cross sections are found to be higher as compared to the predictions of the one-dimensional barrier penetration model. Attempts have been made to explain sub-barrier fusion enhancement by including the static deformations, the couplings to inelastic excitations, and non-fusion channels. Purpose: To investigate factors which influence the sub-barrier fusion in the 37Cl + 130Te system and to understand the interplay of couplings, the fusion excitation function was measured at energies from 10% below to 15% above the Bass barrier. Method: The fusion excitation function was measured by employing a recoil mass spectrometer, the Heavy-Ion Reaction Analyser (HIRA), at the Inter-University Accelerator Centre, New Delhi. To study the behavior of the fusion excitation function and the effect of couplings at sub-barrier energies, the excitation function was analyzed in the framework of the coupled-channels code CCFULL. Results: In the present work, the fusion cross section was measured down to 1 μb at the lowest measured energy, i.e., 10% below the barrier. It was found that the inclusion of couplings of low-lying excited states along with the modified barrier between interacting nuclei satisfactorily reproduces the fusion excitation function of the 37Cl + 130Te system. For better insight into the sub-barrier fusion, the fusion barrier distribution, the logarithmic derivative L(E) factor, and the astrophysical S factor were extracted from the analysis of the experimentally measured fusion excitation function. Conclusions: The analysis of the fusion excitation function in terms of the astrophysical S factor and the L(E) factor suggests the absence of fusion hindrance in the 37Cl + 130Te system down to a 1 μb cross section achieved at the lowest measured energy. The excitation function of the present system is compared with the existing measurements in which 37Cl has been used as a projectile to understand the interplay of entrance-channel parameters in sub-barrier fusion enhancement