Secondary emission yields for 3-50 keV H0 atoms striking a copper target

By measuring the fractions of all three charged particles (H-, H+, and H0) emerging from energetic (3-50 keV) collisions of H- ions with helium atoms, the absolute secondary negative particle emission yields γ have been determined for H0 atoms striking a copper surface at an angle of incidence of 30 relative to the normal to the copper surface. The measured secondary emission yields monotonically increase from a value of 1.6 negative particles per atom at an incident energy of 3 keV to a value of 4.0 negative particles per atom at an incident energy of 50 keV. The impact energy dependence of the yield γ is found to be similar to the energy dependence of the yield γ exhibited by the data of previous investigators, which were obtained at projectile angles of incidence different from 30 . (orig.)