Practical Electron Microscopy and Database

An Online Book, Second Edition by Dr. Yougui Liao (2006)

Practical Electron Microscopy and Database - An Online Book

Chapter/Index: Introduction | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Appendix

Electron-Beam Deflecting/Scanning Coil Control System in EMs

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.

Example of computer-controlled EMs: SEM 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.

Schematic illustration of the probe-forming electron optics 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.

Schematic diagram of an SEM system with a thermionic electron gun

Figure 4225c. Schematic diagram of an SEM system with the scan coil indicated.