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Influence of large angle polepiece on spherical aberration coefficient
Jincan Su1, Xiaotian Hu1, Tao Hu1
1School of Energy, Xiamen University, Xiamen, China.
Journal of Microscopy
|May 16, 2025
Summary
Optimizing polepiece angles in transmission electron microscopy significantly reduces spherical aberration. An azimuthal angle of 30° for the upper polepiece minimizes aberrations, improving electron collection efficiency.
Area of Science:
- Physics
- Materials Science
- Electron Microscopy
Background:
- Efficient collection of emitted electrons and X-rays is crucial for advanced transmission electron microscopy (TEM).
- Spherical aberration negatively impacts imaging quality and resolution in electron optics.
Purpose of the Study:
- To investigate the impact of polepiece geometry, specifically angles, on spherical aberration coefficients.
- To optimize polepiece design for enhanced electron collection efficiency in TEM.
Main Methods:
- Utilizing the finite element method (FEM) for precise simulations.
- Analyzing the effects of varying azimuthal angles (β) of the upper polepiece.
Main Results:
- The azimuthal angle (β) of the upper polepiece significantly influences the spherical aberration coefficient.
- A minimum spherical aberration coefficient was achieved at β = 30°.
- Higher angles (β ≥ 50°) led to a substantial increase in spherical aberration, degrading imaging.
Conclusions:
- The azimuthal angle is a critical parameter for designing low-aberration polepieces in TEM.
- This research provides a new design approach for large-angle electron/X-ray collection systems and objective lenses.
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