Study of Resonant States inC13by Scattering of Fast Neutrons onC12

Total elastic and inelastic scattering cross sections for fast neutrons are measured on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ between 17 and 20.5 MeV in order to check the validity of standard optical-model parameters and to investigate the nature of resonant states in ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$. The region around 18 MeV is found to be free of isolated resonances, and good fits are obtained with standard parameters. A resonant state is apparent at an energy corresponding to 23 MeV in ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$, and indications of the spin and the structure of this state are obtained.