Back-scattered and secondary electron imaging
The back-scattered electron (BSE) and secondary electron (SE) detectors are mounted inside the sample chamber, which also hosts the EDS detector and the sample stage. The BSE detector is mounted above the sample, whereas, the SE and EDS detectors are mounted on the side. The SE detector provides a topographic image accentuating the fractures, ridges and holes. Below is an SE image of a cross-section of a tree stump:
The BSE detector is most useful in compositional imaging (A+B mode), but it can also be used in a differential mode (A-B mode) to obtain topographic images. Below are BSE images in A+B mode (left) and A-B mode (right) of a Zn-Sn composite:
