Sequential Reactions Induced by Alpha Particles onHe3

A prominent peak is observed in the forward-angle spectra of $\alpha$ particles if ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ is bombarded by 63.7-, 71.7-, or 81.4-MeV $\alpha$ particles. The energy of the peak is consistent with a sequential decay process involving the 2.18-MeV state of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$. At 71.7 MeV, proton spectra measured at backward angles show that the cross sections for formation of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}_{}^{*}{}_{}{}^{}$ (2.18 MeV) agree with the intensity of the prominent $\alpha$ peak. The peak shape and position imply that the $\alpha$ particles are preferentially emitted forward with respect to the original ${}_{}{}^6{}_{}{}^{}\mathrm{Li}_{}^{*}{}_{}{}^{}$ direction. Two other peaks are observed in some of the $\alpha$ spectra, one of them possibly the result of a sequential decay involving ${}_{}{}^5{}_{}{}^{}\mathrm{Li}$.