Elastic and inelastic scattering cross-sections of amorphous layers of carbon and vitrified ice

Abstract

Elastic and inelastic scattering cross-sections of amorphous layers of carbon and vitrified ice have been determined by electron spectroscopic diffraction (ESD). Using an energy-filtering TEM (EFTEM), elastic and inelastic differential scattering distributions were recorded separately on Image Plates (IP) and quantified. The thickness of carbon films was measured photometrically, that of ice layers by direct imaging. The elastic cross-sections are in good agreement with theory and previous experimental data. The measured inelastic scattering cross-sections 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 scattering indicates the importance of zero-loss energy filtering for imaging of biological samples embedded in amorphous ice.