Electron-probe Microanalyzer

electron-probe microanalyzer, type of electron microscope used to provide chemical information. (A limitation of the conventional electron microscope is that it provides no elemental analysis.) Electron-probe microanalyzers have been developed since 1947 to carry out nondestructive elemental analysis at resolutions approaching those of the transmission electron microscope (TEM). This is done by measuring the energy and intensity of the characteristic X-rays emitted by a specimen when a focused electron beam impinges on it. As in the scanning electron microscope (SEM), the probe is scanned so that an image of the distribution of a chosen element may be built up on a cathode-ray tube.

X-ray microprobe analysis has proved to be so valuable that a majority of SEMs, as well as many TEMs, are now equipped with X-ray spectrometers as accessories. The technique has found wide applications in mineralogy, metallurgy, and solid-state science, as well as in the clinical and life sciences.