Population of high-spin states inNa23through theB11(O16, α)reaction

Abstract

States in ${}_{}{}^{23}{}_{}{}^{}\mathrm{Na}$ were populated with the ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}({}_{}{}^{16}{}_{}{}^{}\mathrm{O}, \alpha )$ reaction. Energy-averaged differential cross sections were measured in the energy range $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=16.9-18.5\mathrm{}$ MeV for 29 excited states in ${}_{}{}^{23}{}_{}{}^{}\mathrm{Na}$ from 0 to 15 MeV of excitation, and for the laboratory angles of 7, 15, 25, and 150°. Single energy differential cross sections were measured for laboratory angles of 40, 55, and 70° at a bombarding energy of 43.2 MeV. The experimental angular distributions were compared with Hauser-Feshbach calculations, and good agreement was found for the states of known spin values in ${}_{}{}^{23}{}_{}{}^{}\mathrm{Na}$. Candidates for high-spin states in ${}_{}{}^{23}{}_{}{}^{}\mathrm{Na}$ were selected for the groundstate rotational band, and for the $K={\frac{1}{2}}^{+}$ and $K={\frac{1}{2}}^{-}$ bands. The reliability of using Hauser-Feshbach calculations for spin assignments is discussed, and a comparison of the suggested excitation energies for highspin states with shell-model calculations is presented.