Several componets of electron beam systems can be sources of electromagnetic radiation which can couple with the Si detector system and introduce artifacts. Typical instrumental sources for this radiation include power supply transformers, scan generators, scan coils, computers and logic circuits, and motors. Figure 1 show the problem of scan coils of 200 keV analytical electron microscope.


Figure 1:Anomalous peak observed in 0-2 keV region in
analytical electron microcope; the peak position varied with
the magnification setting (magnification 9500 X, 7200 X, and
5000 X, left to right peaks, frame 1/s).