Photoprotons from Aluminum

The energy and angular distributions of photoprotons from aluminum induced by 24 Mev bremsstrahlung were measured using nuclear emulsions. Many proton peaks were observed in the energy distribution. The energies of these peaks were compared with the results of calculations and experiments on ( gamma ,n). The proton peaks from direct transitions between intrinsic single particle levels in deformed nucleus were calculated and they are too few to explain all the structures in the energy distribution. If the structures are neglected, the observed energy distribution agrees well with the calculated one using the statistical theory. The angular distributions were compared with the calculations of compound process and direct process. They suggest that protons are emitted by compound process in low energy and by direct process with d or lower orbital angular momentum in high energy. (auth)