Electromagnetic Quadrupole Design for Cs Corrector 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.



Figure 4316 shows the quadrupole design 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. Figure 4316 also shows 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 focus).

quadrupole design for spherical aberration (Cs) correction

Figure 4316. The quadrupole design for spherical aberration (Cs) correction.

Combination of four magnetic quadrupoles with at least three octupoles [1] is normally employed for spherical aberration correction at high accelerating voltages in STEM system due to its off-axis aberrations.


[1] Krivanek, O. L., Dellby, N., and Lupin, A. R. 1999. Towards sub-Å electron beams, Ultramicroscopy, 78, 1–11.



The book author (Dr. Liao) welcomes your comments, suggestions, and corrections, please click here for submission. You can click How to Cite This Book to cite this book. If you let Dr. Liao know once you have cited this book, the brief information of your publication will appear on the “Times Cited” page. This appearance can help advertise your publication.

Copyright (C) 2006 GlobalSino, All Rights Reserved