A deflector for electron-beam deflection in EMs has been applied to align, tilt, shift, scan the electron beam, and so on. The deflector, usually including a pair of deflection coils, is called the double-deflection system.
Figure 4225a shows an example of SEM systems. In all EMs (electron microscopes), electron-beam deflecting/scanning coils are controlled by electron-beam deflecting/scanning coil control systems. For instance, the electron beam is scanned on the specimen by the electron-beam deflecting/scanning coil control system.
Figure 4225a. Example of computer-controlled EMs: SEM system.
Figure 4225b shows the structure of the electron probe-forming system in STEM mode in JEOL JEM-2010F TEMs.
Figure 4225b. Schematic illustration of the probe-forming electron optics in STEM mode in JEOL JEM-2010F TEMs.
The scan coil in SEM is schematically shown in Figure 4225c.
Figure 4225c. Schematic diagram of an SEM system with the scan coil indicated.