Inelastic Scattering in the2s−1dShell. I. Even-ANuclei

The inelastic scattering of 17.5-MeV protons from a number of nuclei in the $2s-1d$ shell has been studied using lithium-drifted silicon detectors. Results for the even-$A$ nuclei ${\mathrm{O}}^{16}$, ${\mathrm{Mg}}^{24}$, ${\mathrm{Mg}}^{26}$, ${\mathrm{Si}}^{28}$, and ${\mathrm{S}}^{32}$ are presented here. Angular distributions are obtained for up to twenty levels in each nucleus. While some of the angular distributions having the same $l$ value are similar, there were a number of cases where angular distributions to states in the same nucleus with the same spin and parity have very different angular distributions. The differential cross sections for the most strongly excited levels are compared with a distorted-wave Born-approximation calculation using collective form factors. Reasonable fits to the differential cross sections were obtained for the $l=2\mathrm{}$ transitions to the first excited states of ${\mathrm{Mg}}^{24}$, ${\mathrm{Si}}^{28}$, and ${\mathrm{S}}^{32}$ and for the $l=3\mathrm{}$ transitions to the lowest-lying $3^{-}$ states of ${\mathrm{O}}^{16}$, ${\mathrm{Mg}}^{24}$, ${\mathrm{Si}}^{28}$, and ${\mathrm{S}}^{32}$. A previously unreported level in ${\mathrm{S}}^{32}$ at 6.76 MeV was observed.