Gamma radiation from the alpha particle bombardment of C 12

Abstract

The excitation function of the reaction C 12( α, γ)O 16 has been studied over the region E α = 2.8 to 8.3 MeV using a NaI(Tl) detector and enriched C 12 targets. Resonances were observed at E α = 3.24, 3.58, 4.26, 5.81, 7.05, 7.88 and 8.13 MeV, corresponding to O 16 states at E x = 9.59, 9.85, 10.36, 11.52, 12.45, 13.07 and 13.26 MeV. Radiative widths Γ γ for groundstate radiation from the states at 9.59, 9.85, 11.52 and 12.45 MeV were measured to be 0.022±0.005, 0.0059±0.0006, 0.66±0.09 and 7±1 eV. Radiative widths for cascade radiation from the 9.85 and 10.36 MeV states through intermediate states of O 16 were measured to be 0.0012±0.0004 and 0.046±0.006 eV. Interference effects in ground-state radiation from the 13.07 MeV (1 −) state support evidence for an underlying 2 + state at nearly the same energy. The excitation function for 4.43 MeV gamma radiation from the reaction C 12( α, α′ γ)C 12 has been studied over the region E α = 7.5 to 10.5 MeV. Resonances were observed at E α = 7.96, 8.14, 8.98, 10.08 (broad) and 10.20 MeV, corresponding to O 16 states at E x = 13.13, 13.27, 13.90, 14.72 and 14.81 MeV.