During the beam-surface interaction, several mechanisms take place, such as those involving secondary electrons (SEs), backscattered electrons (BSEs), and X-rays, as shown in Figure 3.1b(ii). SEs are ejected from the sample aer colliding with atoms in the upper layers of the surface and are collected by the SE detector and used for imaging the surface topography. In addition to the emission of SEs are the BSEs, which are detected using a solid-state detector (Everhart-ornley detector). e intensity of BSE is dependent on the atomic number of the sample material, accelerating voltage, and interaction volume. Importantly, the BSEs are used to create compositional maps of the specimen. However, because the interaction volume is greater for BSEs, the resolution is usually of lower quality than those of SEs. In addition to the SEs and BSEs, the SEM also produces characteristic X-rays, which can be used to determine the elements present in the sample material. erefore, by scanning the sample surface topographical features and composition, data can be viewed, stored, or recorded as a micrograph.