"BREAKS" IN THE ACTIVATION CURVE OF THE P$sup 31$($gamma$,n)P$sup 30$ REACTION

Discontinuities in the slope of the activation curve of the p/sup 31/( gamma ,n)P/sup 30/ reaction were found while using two large NaI(Tl) crystals to detect the annihilation gammas from P/sup 30/. These breaks correspond well with resonances found recently in the Si/sup 30/(p,n)P/sup 30/ reaction. The correspondence between breaks and known resonances in some light nuclei is discussed. Such a correspondence was found to exist in the case of N/sup 14/, F/ sup 19/, and P/sup 31/ and is in doubt in the case of C/sup 12/. The det ection system used allowed accurate measurements of the thresholds of the P/sup 31/( gamma ,n)P/sup 30/ reaction (12.23 plus or minus 0.04 Mev) and the Cl/sup 35/( gamma ,n)Cl/sup 34/ reaction (12.66 plus or minus 0.04 Mev). (auth)