INFLUENCE OF THE POLYCRYSTALLINE STRUCTURE OF THIN COPPER FOILS ON THE ENERGY-LOSS OF TRANSMITTED 300 KEV IONS

The use of polycrystalline target foils for energy loss measurements is discussed. It is shown that for 300 keV nitrogen and neon ions the derived electronic stopping cross sections approach the cross sections expected for amorphous foils (if only particles deflected by an angle larger than about 6° are analysed). The distortion of the energy spectra relative to amorphous targets for smaller angles is explained by channelling of ions in the small crystallites forming the foil. These distortions are shown to increase with foil thickness and ion mass. They decrease with increasing ion energy. © 1979.