The Resonance Processes in the Disintegration of Boron by Protons

Abstract

The yields of long range alpha-particles and gamma-rays from the disintegration of boron by protons having energies from 150 to 195 kev were measured simultaneously. The shapes of the yield curves indicate that the yields for the two processes are proportional and that the resonances occur at the same voltage, to within 1 kev. A determination of the alpha-particle yield places the resonance point at 165±4 kev. Thus it is highly probable that both resonance processes involve the same level in the excited ${\mathrm{C}}^{12}$ nucleus. The unsatisfactory findings of Oppenheimer and Serber are therefore probably not due to their assumption concerning the association of the resonances with the same energy level of the compound nucleus. The half-breadth of the alpharesonance was estimated to be 6 kev, and could be accounted for by the spread in energy of the ion beam. Thus the estimates of Oppenheimer and Serber concerning the sharpness of the resonance processes are here supported.