The ability to identify small particles and other materials in the electron microscope is greatly enhanced by the common addition of energy dispersive x-ray spectrometry (EDS) capability.
In the microscope, the bombardment by the energetic electron beam induces the emission of x-rays at energies which are characteristic of the elements present in the sample.
These x-rays are collected, sorted and counted and the result is presented as an EDS spectrum in which the presence of peaks indicates the presence of the associated element.
In addition, the height of the peaks can be related to the concentration of the element, so that quantitative elemental analysis is possible.
The spectrum below identifies a metal particle as stainless steel, allowing its source in the processing stream to be identified.