In secondary electron imaging, the electron microprobe is used as an electron microscope to provide a magnified image of the surface of a sample. The technique is useful in examining the features down to a few μm in size. Secondary electrons are formed when beam interaction with atoms in the sample causes loosely bound, low energy electrons (⤠50 eV) to move through the sample. Due to their low energy, only secondary electrons formed near the point of beam impact can escape the sample and be detected which allows imaging of surface features. The pictures below are secondary electron images of grains of table salt taken at two different magnifications.
