What is Backscattered Electron Imaging?
Since the microprobe also functions as a Scanning Electron Microscope (SEM), we can generate highly magnified images of our samples. Backscattered electrons have higher energies than secondaries, and are produced when electrons from the primary beam are “bounced” back out of the sample by elastic collisions with atoms. The number of electrons a given atom will backscatter is proportional to its mean atomic number. Materials composed of larger, heavier atoms will backscatter more electrons, producing brighter gray tones in the images than less dense materials (differences in average atomic mass of 0.1 amu can be resolved). Backscattered electrons thus produce an image that is related to material composition, providing both spatial and chemical information.
