Effect of Temperature on the Angular Distribution of Backscattered Protons in Gold and Zinc

Abstract

The influence of thermal vibrations on the angular distribution of the yield of backscattered protons (incident energy 100 keV) has been investigated for various axial and planar dips in gold and zinc. The angular distributions were markedly influenced by the crystal temperature and by the depth beneath the crystal surface from which the protons were scattered. In gold, data were obtained over the range 77–873 °K and the angular width ψ of the distributions was observed to vary exponentially with the root-mean-square vibrational amplitude ρ regardless of the scattering depth. Also in gold, the minimum yield χ_min was found to be proportional to ρ² for those protons scattered from near the crystal surface but a deviation from this behavior was noted as the depth of scattering increased. In zinc, data were obtained at 77 and 295 °K and the magnitude of the observed temperature effect was at least as large as in gold when compared on the basis of root-mean-square vibrational amplitudes. The experimental results are compared with analytical and computer results of other investigators.