The Emission of Secondary Electrons from Metals Bombarded with Protons

A study has been made of the yield of secondary electrons from various metals bombarded with protons. For metals that have not been outgassed the secondary electron-proton ratio was about three for protons having energies between 48 and 212 kev. The ratio from outgassed targets of C, Cu, Ni and Pt was about two for protons of the same energies as above. Be gave a yield of about 7.5 electrons per proton. The secondary electron yield was found to be proportional to the cosecant of the angle between the proton beam and the target.