Post-fields of Objective Lens
- Practical Electron Microscopy and Database -
- An Online Book -

http://www.globalsino.com/EM/  



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

=================================================================================

Figure 2772 shows the full view of of the practical double-sextupole Cs correctors for STEM and for TEM, respectively. The positions of the correctors with respect to the pre- and post-fields of objective lenses for STEM and TEM, respectively, are also indicated.

Double-sextupole spherical aberration correctors for: (a) STEM and (b) TEM

Figure 2772. Double-sextupole spherical aberration correctors for: (a) STEM and (b) TEM.

Due to the significant energy spread in the electron beam, the chromatic aberration associated with the lenses will lead to image degradation in TEM as listed in Table 2772.

Table 2772. Causes of energy spreads and the image degradation induced by the associated lenses.

Causes of energy spread Lenses inducing image degradation
Variation of HT (high tension) Both pre-field of objective lens and post-fields of objective lens
Energy spread in electron source Both pre-field of objective lens and post-fields of objective lens
Interaction between incident electrons and specimen Post-fields of objective lens

 

 

=================================================================================

The book author (Yougui Liao) welcomes your comments, suggestions, and corrections, please click here for submission. If you let book author know once you have cited this book, the brief information of your publication will appear on the “Times Cited” page.