The trapping of3He and4He ions with energies between 10 eV and 40 keV in polycrystalline Al and Pt and in BeO and anodic Al2O3films has been studied. The measured collecting efficiencies vary from a few times at 10−4at 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.