Fusion cross sections were measured for the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ + ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$ system at two ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ bombarding energies, 98 and 117 MeV. The extracted fusion cross sections are 946 ± 74 mb for $E\left({}_{}{}^{12}{}_{}{}^{}\mathrm{C}\right)=98\mathrm{}$ MeV and 889 ± 89 mb for $E\left({}_{}{}^{12}{}_{}{}^{}\mathrm{C}\right)=117\mathrm{}$ MeV. The critical angular momenta for fusion deduced from the cross section measurements equal, within $1\hslash$, the values deduced from ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ + ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ and ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$ + ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$ at the same excitation energies, thus indicating a compound nucleus limitation for fusion.

NUCLEAR REACTIONS ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ + ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$, $E\left({}_{}{}^{12}{}_{}{}^{}\mathrm{C}\right)=98\mathrm{} \mathrm{and} 117$ MeV; gas cell target; measured $\frac{d^2\sigma }{d\Omega \mathrm{dE}}$ for reaction products with $Z=7\mathrm{} \mathrm{to} 12$. Extracted ${\sigma }_{\mathrm{fus}}$.

• Received 22 July 1982

DOI:https://doi.org/10.1103/PhysRevC.26.2664