Radiative capture above the giant resonance in C12

Abstract

Excitation functions for the radiative capture reaction, B11(p, γ)C12, to the ground and first excited states of C12 have been measured in the region above the giant resonance (Ep = 15 to 25 MeV. A component of the dipole state, predicted at an excitation energy of 34.3 MeV in C12 by the particle-hole calculations of Vinh-Mau and Brown, has been found at an energy of 34.4±0.5 MeV. However, the ratio of proton capture at the 34.4 MeV state to that at the main dipole component at 22 MeV is an order of magnitude less than that implied by the Vinh-Mau and Brown model.Some data have been obtained for the reaction Li7(p, γ)Be8. Both experiments suggest giant dipole resonances built on the first excited states of Be8 and C12.