SECONDARY-ELECTRON SPECTROSCOPY AND IMAGE-RESOLUTION IN A SCANNING-TRANSMISSION ELECTRON-MICROSCOPE

A simple secondary electron (SE) spectrometer has been designed and implemented on a VG Microscopes HB5 dedicated STEM. It is shown that the high resolution images are indeed formed by SEs with energies of a few electron volts. Simple estimates of interaction localization are shown to be consistent with this resolution for most of the relevant interactions. However, the observed resolution favours a larger contribution from the more localized core excitations than is theroretically predicted.