THE STRUCTURE OF SI-28 ABOVE 10 MEV EXCITATION-ENERGY .1. GAMMA-DECAYMODES AND RADIATIVE WIDTHS OF LEVELS

The systematics of gamma-decay modes and radiative widths of highly ex cited states in Si-28 has been extended by taking gamma-ray spectra on 60 resonances of the Al-27(p,gamma) reaction in the range 1097 keV le ss than or equal to E(p) less than or equal to 4492 keV (12643 keV les s than or equal to E(x) less than or equal to 15915 keV) and on the Mg -24(alpha,gamma) resonances at E(alpha) = 3355, 3431, 4003 keV (E(x) = 12860, 12925, 13415 keV). The gamma-decay modes of levels in the sub- resonance region (E(x) = 10-12.5 MeV) were studied with both the Al-27 (p,gamma) reaction and the Al-27(d,n gamma) reaction at E(d) = 4, 5, 6 MeV. Information on radiative widths of levels was obtained by measur ing the resonance strengths S gamma = (21 + 1)Gamma(p) Gamma(y)/Gamma for 52 resonances of the Al-27(p, gamma) reaction with an emphasis on prospective T = 1 states.