Line Focus in EMs
- Practical Electron Microscopy and Database -
- An Online Book -  

This book (Practical Electron Microscopy and Database) is a reference for TEM and SEM students, operators, engineers, technicians, managers, and researchers.


Some operations can be used for “line focusing”. For instance, Figure 3655 shows the quadrupole design, normally for spherical aberration (Cs) correction. The optical axis, along which the electrons travel, is into the page. indicates the direction of the electron beam. The blue lines represent the magnetic field lines, while the red line represents the Lorentz force on the electrons. The quadrupole provides a simple focusing effect in one azimuthal direction while provides simultaneous defocusing in the perpendicular direction. Therefore, the quadrupole can be used to focus the beam into a line (called line focusing).

quadrupole design for spherical aberration (Cs) correction

Figure 3655. The quadrupole design.




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