The fusion cross section for ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$ + ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$ has been measured at four excitation energies in ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ of $E^{*}=48.4, 55.1, 66.9, \mathrm{and} 74.4$ MeV in order to study possible compound nucleus limitation effects on fusion for light heavy-ion systems at intermediate excitation energies. Comparing this data with other measurements for different entrance channels populating the same compound nucleus it is found that for $E^{*}\le 60$ MeV all fusion bands in the $E^{*}-J$ plane of ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ appear to be parallel and displaced by the corresponding differences in separation energies, and that for $E^{*}>60\mathrm{}$ MeV the bands tend to converge indicating a possible compound nucleus limitation effect. The data are compared with existing models for entrance channel and statistical yrast line limitations.

NUCLEAR REACTIONS ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$ + ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$, $E\left({}_{}{}^{17}{}_{}{}^{}\mathrm{O}\right)=54, 72, 104, \mathrm{and} 124$ MeV; measured $\frac{d^2\sigma }{d\Omega \mathrm{dE}}$ for reaction products from $Z=3\mathrm{} \mathrm{to} 12$. Extracted ${\sigma }_{\mathrm{fusion}}$.

• Received 8 October 1981

DOI:https://doi.org/10.1103/PhysRevC.25.1410