Half-wavelength and stopping power for planar-channeled protons in silicon and diamond single crystals

Abstract

Measurements are presented of the energy spectra, obtained for backscattering of planar channeled protons (100–350 keV) in silicon and diamond single crystals. The backscattering geometry is chosen such as to provide high depth resolution. This allows the study of the oscillatory dependence of the backscattering probability along the path of the planar-channeled-protons. The measurements have been performed for a variety of entrance ( φ in) and exit ( φ out) angles with respect to the surface normal. A plot of the energy difference between the peaks in the energy spectrum, resulting from the oscillatory variation of the backscattering robability, vs cos φ in/cos φ out permits the experimental determination of the half wavelengyh and the stopping power in the planar channels. The latter turns out to be larger than the random stopping power.