Energy-Filtering Transmission Electron Microscopy (EFTEM) presents a summary of the electron optics, the electron-specimen interactions, and the operation and contrast modes of this new field of analytical electron microscopy. The electron optics of filter lenses and the progress in the correction of aberrations are discussed in detail. An evaluation of our present knowledge of plasmon losses and inner-shell ionisations is of increasing interest for a quantitative application of EFTEM in materials and life sciences. This can be realized not only by filtering the elastically scattered electrons but mainly by imgaging and analyzing with inelastically scattered electrons at different energy losses up to 2000 eV. The strength of EFTEM is the combination of the modes EELS, ESI, ESD and REM.

No single volume has been entirely devoted to the properties of magnetic lenses, so far as I am aware, although of course all the numerous textbooks on electron optics devote space to them. The absence of such a volume, bringing together in formation about the theory and practical design of these lenses, is surprising, for their introduction some fifty years ago has created an entirely new family of commercial instruments, ranging from the now traditional transmission electron microscope, through the reflection and transmission scanning microscopes, to co lumns for micromachining and microlithography, not to mention the host of experi mental devices not available commercially. It therefore seemed useful to prepare an account of the various aspects of mag netic lens studies. These divide naturally into the five chapters of this book: the theoretical background, in which the optical behaviour is described and formu lae given for the various aberration coefficients; numerical methods for calculat ing the field distribution and trajectory tracing; extensive discussion of the paraxial optical properties and aberration coefficients of practical lenses, il lustrated with curves from which numerical information can be obtained; a comple mentary account of the practical, engineering aspects of lens design, including permanent magnet lenses and the various types of superconducting lenses; and final ly, an up-to-date survey of several kinds of highly unconventional magnetic lens, which may well change the appearance of future electron optical instruments very considerably after they cease to be unconventional."

Towards the end of the 1960s, a number of quite different circumstances combined to launch a period of intense activity in the digital processing of electron micro graphs. First, many years of work on correcting the resolution-limiting aberrations of electron microscope objectives had shown that these optical impediments to very high resolution could indeed be overcome, but only at the cost of immense exper imental difficulty; thanks largely to the theoretical work of K. -J. Hanszen and his colleagues and to the experimental work of F. Thon, the notions of transfer func tions were beginning to supplant or complement the concepts of geometrical optics in electron optical thinking; and finally, large fast computers, capable of manipu lating big image matrices in a reasonable time, were widely accessible. Thus the idea that recorded electron microscope images could be improved in some way or rendered more informative by subsequent computer processing gradually gained ground. At first, most effort was concentrated on three-dimensional reconstruction, particu larly of specimens with natural symmetry that could be exploited, and on linear operations on weakly scattering specimens (Chap. l). In 1973, however, R. W. Gerchberg and W. O. Saxton described an iterative algorithm that in principle yielded the phase and amplitude of the electron wave emerging from a strongly scattering speci men."

Scanning Electron Microscopy provides a description of the physics of electron-probe formation and of electron-specimen interactions. The different imaging and analytical modes using secondary and backscattered electrons, electron-beam-induced currents, X-ray and Auger electrons, electron channelling effects, and cathodoluminescence are discussed to evaluate specific contrasts and to obtain quantitative information.