Trapping of low-energy helium ions in polycrystalline al and Pt and in BeO and anodic Al2O3films at room temperature

Abstract

Abstract The trapping of 3He and 4He ions with energies between 10 eV and 40 keV in polycrystalline Al and Pt and in BeO and anodic Al2O3 films has been studied. The measured collecting efficiencies vary from a few times at 10−4 at eV to ∼ 1 at energies above 10 keV. Except for very low implantation energies (less than ∼ 1 keV), where initially trapped particles are probably released by diffusion, we derive reflection coefficients and compare with current theoretical calculations. Our reflection coefficients obtained for implantation energies larger than 1 keV in Al and Pt are in excellent agreement with calculated values. We have also measured the dependence of the trapping probability on the angle of incidence for 3 keV He ions in Al and Pt.