A breakup process of ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ has been studied by performing the following measurements with a 77 MeV ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ beam; (i) energy and angular distributions of $z=1\mathrm{} \mathrm{and} 2$ particles in the ${}_{}{}^{159}{}_{}{}^{}\mathrm{Tb}$+${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ reaction measured in singles and in coincidence with $\gamma$ rays from some heavy residual nuclei, (ii) out-of-plane angular distributions of $\gamma$ rays taken in coincidence with $\alpha$ particles in the ${}_{}{}^{159}{}_{}{}^{}\mathrm{Tb}({}_{}{}^7{}_{}{}^{}\mathrm{Li}, \alpha x\mathrm{n}){}_{}{}^{162-x}{}_{}{}^{}\mathrm{Dy}$ reaction to deduce the spin alignment involved, and (iii) in-plane and out-of-plane angular distributions of fission fragments measured in coincidence with $z=1\mathrm{} \mathrm{and} 2$ particles emitted in the reaction of ${}_{}{}^{232}{}_{}{}^{}\mathrm{Th}({}_{}{}^7{}_{}{}^{}\mathrm{Li}, xf)$ to extract the magnitude and alignment of the transferred angular momenta. The observed energy spectrum of tritons and $\alpha$ particles measured at forward angles exhibits a broad bump centered at a kinetic energy corresponding to the beam velocity, which is characteristic of the breakup mechanism. Roughly a half of the yield at this bump has been shown to originate from a breakup-fusion process, in which one of the breakup fragments is captured by a target nucleus. It is also shown that angular momenta transferred to residual nuclei by breakup fusion are well aligned along the normal to the reaction plane and have the magnitude, on the average, consistent with a direct reaction process occurring at the surface region of projectile and target nuclei.

NUCLEAR REACTIONS ${}_{}{}^{159}{}_{}{}^{}\mathrm{Tb}({}_{}{}^7{}_{}{}^{}\mathrm{Li}, x)$, (${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, $\alpha x\mathrm{n}$), $E=77\mathrm{}$ MeV; measured $\sigma (E_x, {\theta }_x)$, $\alpha -\gamma$ coin, angular correlations $W\left({\theta }_{\gamma }\right)$ of discrete $\gamma$ rays; deduced $\sigma \left(E_{\alpha }\right)$ in coin with final nuclei; ${}_{}{}^{232}{}_{}{}^{}\mathrm{Th}({}_{}{}^7{}_{}{}^{}\mathrm{Li}, xf)$, $E=77\mathrm{}$ MeV; measured $x-f$ angular correlations; deduced magnitude and alignment of average $J$. Average $l$ for particle emission.

• Received 2 May 1983

DOI:https://doi.org/10.1103/PhysRevC.28.1975