Levels of ¹³C near E_x=12 meV from elastic n+¹²C scattering

The excitation energies, spins, parities, total widths and neutron elastic scattering widths of seven T=¹/₂ levels of ¹³C at excitation energies between 11.5 and 12.5 MeV have been determined via a phase-shift analysis of n+¹²C total cross section, elastic differential cross section and analysing power data in the energy range from 7.03 to 8.56 MeV. The proposed level structure for ¹³C is consistent with the known structure of the mirror nucleus ¹³N. Above 12 MeV excitation energy, the results of the phase-shift analysis disagree significantly with the R-matrix analysis of n-¹²C cross section data recently reported by Knox and Lane (1982).