Single crystal spot patterns detection

As illustrated by Fig. 10.4, an electron microscope offers additional possibilities for analyzing the sample. Diffraction patterns (spots from a single-crystal particle and rings from a collection of randomly oriented particles) enable one to identify crystallographic phases as in XRD. Emitted X-rays are characteristic for an element and allow for a determination of the chemical composition of a selected part of the sample (typical dimension 10 nm). This technique is called electron microprobe analysis (EMA, EPMA) or, referring to the usual mode of detection, energy dispersive analysis of X-rays (EDAX or EDX). Also the Auger electrons carry information on sample composition, as do the loss electrons. The latter are potentially informative on the low Z elements, which have a low efficiency for X-ray fluorescence. 

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