$\alpha$-particle groups from the ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}(t, \alpha ){}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ reaction have been studied using thin self-supporting boron films isotopically enriched to 98% in ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$ and surface-barrier detectors. Angular distributions of tritons elastically scattered by ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$ and of $\alpha$ particles leaving ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ in its ground and first-excited states were measured at triton energies ranging from 1.00-2.10 MeV. The elastic-scattering data were analyzed with the optical model, and the reaction data were analyzed with the distorted-wave Born approximation for $p$ proton pickup. $\alpha$-particle potentials having deep wells as opposed to shallow ones were found to provide best fits to the reaction data. The ratio of the spectroscopic factor of the first-excited state in ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ to that of the ground state, found from the fits to the data, is in reasonable agreement with the value obtained from shell-model calculations.

• Received 6 January 1969

DOI:https://doi.org/10.1103/PhysRev.181.1512