ABSTRACT
This chapter describes the physics and optics of gas field ionization (GFI) emitters. The GFI emitter is used in two related but distinct ways: as an emitter for a projection microscopy and as a source for a focused ion beam system, called a gas field ionization source. Electroforming has a long history and is also used for preparing field electron emitters and scanning probes. In principle, the spherical charged particle emitter and Muller emitter give rise to microscopes/machines of three general kinds. Machines of the first kind are the field electron microscope and field ion microscopy. Machines of the second kind include electron microscopes and scanning ion microscopes. In machines of the third kind, the first conceptual object would be focused to give a magnified and unblurred image of the real object. Thereby displaying information about how the rate of the chemical reaction noted earlier varies with position in the critical surface.
