SMALL-ANGLE BACKSCATTERING OF HYDROGEN, DEUTERIUM, HELIUM AND NEON FROM SINGLE AND POLYCRYSTALLINE NICKEL

Ion beams of H, D, He and Ne with incident energies of 1. 5 to 20 keV were directed onto a (110)Ni single crystal surface and a polycrystalline Ni target. Ions and neutral atoms scattered at 15 degree under specular conditions were energy analyzed. For the single crystal the influence of the crystal orientation with respect to the scattering plane was investigated. The measured energy distributions are compared with MARLOWE computer simulatioand with the analytical multiple scattering theory of Firsov et al. Within the errors satisfactory agreement between the results of the experiment and both theories was found. This was possible because the neutral backscattered particles were measured. This avoids difficulties which arise from energy and angular dependences of the neutralization probabilities when only ions are measured.