Electron Source Brightness and Illumination Semi-Angle Distribution Measurement in a Transmission Electron Microscope

Area of Science:

• Materials Science
• Physics
• Analytical Chemistry

Background:

• Electron source brightness is a critical parameter for electron microscopy performance.
• Existing methods for measuring brightness and illumination semi-angle distribution are often complex or poorly documented.

Purpose of the Study:

• To develop and demonstrate a facile measurement route for electron source brightness and illumination semi-angle distribution.
• To validate the method on a state-of-the-art transmission electron microscope.

Main Methods:

• A novel, straightforward measurement protocol was established for determining brightness and illumination semi-angle distribution.
• The method was applied to a FEI X-FEG electron source equipped with a monochromator.

Main Results:

• The reduced axial brightness was successfully determined.
• The measured reduced axial brightness exceeded 10^8 A/(m^2 sr V).

Conclusions:

• A practical and reliable method for measuring key electron microscope parameters has been demonstrated.
• The results confirm the high performance of advanced electron sources like the FEI X-FEG.