Elastic scattering and transfer reactions induced by 100 MeVS32onAl27

Abstract

Angular distributions have been obtained at an incident energy of 100 MeV corresponding to ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$ elastic scattering on ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$, ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ (${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$, ${}_{}{}^{31}{}_{}{}^{}\mathrm{P}$) transitions to the ground and first-excited states of ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ and ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ (${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$, ${}_{}{}^{33}{}_{}{}^{}\mathrm{S}$) transitions to an unresolved group of low-lying states in ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$. An optical model analysis of the elastic data shows that the "best fit" potentials with constant diffusivity follow the $V{e}^{\frac{R}{a}}=\mathrm{constant}$ ambiguity extremely well. It appears that the elastic data is most sensitive to the ion-ion potential near a radius of ≈ 10.1 fm. The absolute cross sections of the ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ (${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$, ${}_{}{}^{31}{}_{}{}^{}\mathrm{P}$) transitions to the ground and first-excited states of ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ are well reproduced in a distorted-wave Born-approximation analysis using optical model parameters which reproduce elastic scattering. The angular positions of the (${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$, ${}_{}{}^{31}{}_{}{}^{}\mathrm{P}$) grazing peaks, however, are observed a few degrees forward of their predicted position, and the measured cross sections forward of the grazing peaks are considerably larger than predicted. The agreement between measured and predicted angular shape apparently is better for the ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ (${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$, ${}_{}{}^{33}{}_{}{}^{}\mathrm{S}$)${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ neutron transfer than for the proton transfer data. From this limited first data for ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$ induced reactions it appears that such reactions can be explained to the extent that "lighter heavy-ion" induced reactions are understood.