Mechanism of the 32S( 3He, α) 31S reaction at bombarding energies of 4.60, 5.05 and 5.50 MeV

Abstract

Angular distribution of alpha particles from the 32S( 3He, α) 31S reaction, leading to the ground state of 31S, were measured at bombarding energies of 4.60, 5.05 and 5.50 MeV, using a semiconductor device as detector. The angular distributions show typical oscillatory behaviour with pronounced peaks in the backward direction, which are very sensitive to the bombarding energy. The experimental results have been fitted by the square of an expansion of Legendre polynomials according to the formalism of the DWBA pick-up theory, for the particular case of a momentum transfer l = 0. The coefficients of the Legendre polynomials, extracted from the experimental results, are peaked mostly near the classical cut-off, indicating a process of pick-up mechanism under condition of strong absorption. In addition, the presence of a large coefficient for the s partial waves seems to indicate that a compound nucleus mechanism is present, interfering with the direct interaction.