Excitation functions were measured radiochemically for the ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ti}$(n,α${)}^{45}$Ca and ${}_{}{}^{50}{}_{}{}^{}\mathrm{Ti}$(n,α${)}^{47}$Ca reactions over the neutron energy range of 12.6 to 19.6 MeV. Use was made of low-level anticoincidence ${\mathrm{\beta }}^{\mathrm{-}}$ counting in the radioactivity measurement of ${}_{}{}^{45}{}_{}{}^{}\mathrm{Ca}$ and of high-resolution γ-ray spectroscopy in the case of ${}_{}{}^{47}{}_{}{}^{}\mathrm{Ca}$. Statistical model calculations taking into account preequilibrium effects described the proton emission well; the calculated ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ emission results were, however, consistently lower than the experimental data, both as regards emission spectrum and excitation function. Inclusion of direct three-nucleon pickup component in the ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ emission calculation improved the agreement between theory and experiment.

• Received 23 March 1992

DOI:https://doi.org/10.1103/PhysRevC.46.1398