1. An instrument which focuses an accelerated beam of electrons to an extremely small point on the surface of a crystal specimen so it can be studied by the effects of the electron beam.
2. An X-ray machine in which electrons transmitted from a hot-filament source are accelerated electrostatically, then focused to an extremely small point on the surface of a specimen by an electromagnetic lens.

A nondestructive analysis of the specimen can then be made by measuring the back-scattered electrons, the specimen current, the resulting X-radiation, or any other resulting process.

3. A technique of analysis using the electron microscope based on spectral analysis of the scattered X-ray emission from the specimen induced by the electron beam.

By using this technique, it is possible to obtain quantitative data on, for example, the calcium concentration in different parts of a cell; however, it is necessary to use ultra thin frozen sections.