Unconventional and New Techniques

Abstract

This chapter describes fairly briefly a number of imaging techniques that are not widely used at the time of writing, either because they are rather specialised in their application or because they are relatively new and are not yet established. Since all of these techniques use electrons to form the image, in many cases the equipment is basically similar in design to microscopes described in earlier chapters. An instrument has been included in this chapter if it satisfies the criterion of producing contrast in a partly or wholly new way. For example, high-voltage microscopes are in a sense unconventional, in that their cost makes them relatively rare. Also, they tend to be used for studies in which their higher electron energy is either an advantage (for example, studying thicker materials to see the three-dimensional arrangement of the sub-structure) or a necessity (studying dynamical diffraction effects or producing in situ electron radiation damage). However, they are not considered in this chapter since there is no new principle or technique involved in producing contrast, although in practice the image contrast may appear to be different as a consequence of several strong reflections occurring simultaneously. On the other hand, the mirror electron microscope is included, since it produces contrast in ways not possible with other instruments.