DETERMINATION OF THE EXCITED LEVELS OF CARBON NUCLEI BETWEEN 18 AND 21 Mev FROM THE PHOTONEUTRON REACTION

sup 12/( gamma ,n) C/sup 11/ was obtained using a 31-Mev betatron. The slope of this curve has dis-continuities (or breaks'') which show that the photons can be absorbed by narrow resonances corresponding to excited levels of the initial nucleus or the final nucleus. Discontinuities were found at 18.86, (J.S.R.)