ELASTIC AND INELASTIC-SCATTERING CROSS-SECTIONS OF AMORPHOUS LAYERS OF CARBON AND VITRIFIED ICE

Elastic and inelastic scattering cross-sections of amorphous layers of carbon and vitrified ice have been determined by electron spectroscop ic diffraction (ESD), Using an energy-filtering TEM (EFTEM), elastic a nd inelastic differential scattering distributions were recorded separ ately on Image Plates (IP) and quantified. The thickness of carbon fil ms was measured photometrically, that of ice layers by direct imaging, The elastic cross-sections are in good agreement with theory and prev ious experimental data. The measured inelastic scattering cross-sectio ns are higher than the values derived from theoretical models for free atoms because these models do not account for collective excitations and binding effects, The short mean free path length for inelastic sca ttering indicates the importance of zero-loss energy filtering for ima ging of biological samples embedded in amorphous ice.