Related Experiment Video
Updated: May 20, 2026
07:27
Quantifying Microorganisms at Low Concentrations Using Digital Holographic Microscopy (DHM)
Published on: November 1, 2017
A holographic method to measure the source size broadening in STEM
Jo Verbeeck1, Armand Béché, Wouter Van den Broek
1EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium. jo.verbeeck@ua.ac.be
Ultramicroscopy
|July 17, 2012
Summary
This study introduces a new method to measure source size broadening in STEM experiments using a holographic biprism. The findings reveal non-Gaussian source profiles with wider tails, crucial for accurate STEM simulations and image analysis.
Area of Science:
- Materials Science
- Electron Microscopy
- Physics
Background:
- Source size broadening is a key factor limiting resolution in Scanning Transmission Electron Microscopy (STEM).
- Accurate characterization of source size is essential for quantitative STEM imaging and simulations.
Purpose of the Study:
- To develop and validate an alternative method for precisely measuring source size broadening in STEM.
- To investigate the actual shape of the demagnified electron source profile.
Main Methods:
- Utilizing a holographic biprism to generate interference patterns in an 'empty' Ronchigram.
- Analyzing the interference patterns to determine the source size broadening profile with high sampling.
Main Results:
- The demagnified electron source profile deviates significantly from the commonly assumed Gaussian distribution.
- Fitting the profile with a Gaussian and bivariate Cauchy distribution revealed considerably wider tails than previously reported.
- The observed wide tails impact image contrast, making it dependent on interatomic distances.
Conclusions:
- The proposed holographic biprism method provides a more accurate measurement of source size broadening.
- The non-Gaussian nature of the source profile, particularly its wide tails, must be considered for precise STEM simulations and experimental interpretation.
- This finding is critical for improving the quantitative accuracy of STEM analyses, especially in resolving fine structural details.
