Angular Distribution of Photo-Protons from Al and Cu

The angular distributions of photo-protons from Al and Cu irradiated with 22 Mev bremsstrahlung are measured. The result of Al shows a marked forward peak for total protons of energies above 2 Mev as well as for those above 6 Mev. The latter can be fitted with 1+0.64sin 2 θ(1+1.5cos θ) 2 . Protons above 7 Mev from Cu have a symmetrical distribution around 90° which can be represented as 1+1.3sin 2 θ, whereas total protons above 2 Mev have isotropic distribution.