ABSTRACT
This chapter investigates imaging possibilities in the low energy-loss region where intensities are higher. Energy-filtered transmission electron microscopy (EFTEM) images are usually recorded at energies around ionisation edges and elementals maps are calculated therefrom. For elemental mapping, images are recorded before and after the ionisation edge energies of the elements of interest and are then combined into elemental distribution maps. Specimen thickness has an important influence on the observed contrast due to multiple scattering, some diffraction contrast is transferred into the low-loss energy region and delocalisation effects may limit imaging resolution. Both specimen thickness and orientation have a strong influence on the image contrast in low energy-loss images and we could determine acquisition parameters to avoid such unwanted effects. The signal-to-noise ratios in the energy region are much greater than in the region of ionisation energy-losses used by other EFTEM methods such as elemental maps or ratio images.
