Electron microscopes: present state and future prospects

After an historical sketch of the development of the electron microscope, the main features of the various types of existing instruments are described. Attention is confined to those which are commercially available, and experimental models are discussed only when they embody significant new ideas. The emphasis is on design and operation. Applications are included only incidentally, and specimen preparation not at all. The transmission electron microscope is dealt with in greatest detail, followed in importance by the scanning electron microscope. Electron- and ion-emission microscopes are also described, and a brief account is given of mirror microscopes and the electron-probe microanalyser. To avoid repetition, certain features common to all or most of these instruments are discussed in an initial Section, in particular electron guns and magnetic lenses. The review concludes with an attempt to chart the further development of electron microscopes by extrapolation of some current trends in their design and uses.