Electron microscopy
 
Axial Coma (B2) Correction with Ronchigram in STEM
- Practical Electron Microscopy and Database -
- An Online Book -
Microanalysis | EM 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 3339a shows the change of Ronchigram taken at overfocus of 50 nm during axial coma C2,1 (B2) correction. The characteristic feature of the aberration marked by white broken lines disappeared after the aberration correction.

Change of Ronchigram taken at overfocus of 50 nm during C1,2 (A1) correction

Figure 3339a. Change of Ronchigram taken at overfocus of 50 nm during axial coma C2,1 (B2) correction. Adapted from [1]

The changes of A1 and B2 from underfocus (UF) to overfocus (OF) are shown in Figure 3667d. At focus (F), the probed area is the smallest and the image blows-up to "infinity" magnification, while the images reverses from UF to OF.

 Aberration corrections

Figure 3339b. Changes of A1 and B2 from underfocus (UF) to overfocus (OF). Adapted from [2]

[1] H. Akima, Y. Hirayama and T. Yoshida, Automated Alignment Cs Correction System for STEM (II): Installation of Reinforcement Learning, www.microscopy.org, 2011 .
[2] FEI Application Instructions: How to tune STEM probe on Cs-corrected Titan.

 

 

 

=================================================================================
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.