ULTRA ELECTRON-MICROSCOPY IN THE SEM AND STEM MODES

The approach, in this paper, to the subject of ultra electron microsco py, is based on the fundamental assumption, that the classical laws of electrodynamics and electrostatics, will apply at all levels of image formation, down to spacings which approach the electron diameter itse lf. The electron optical principles of ultra electron microscopy, are shown to be based on a phenomenon found in cold field-emission sources , namely, a phenomenon where the paraxial emission manifests an electr on density which is orders of magnitude seater than the overall densit y of emission. It is argued, further, that the laws of electrodynamics and electrostatics will be valid, also, in regard to the constitution of the atom, and an example which supports that point of view, is sho wn.