Two-Stage Dodecapole Aberration Corrector for Charged-Particle Beam Resolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current charged-particle beam systems, such as electron microscopes, face limitations in correcting higher-order aberrations like 6-fold astigmatism, which restrict spatial resolution and the range of incident angles that can be corrected, due to the inherent finite thickness of multipole elements and the inability of existing aberration correctors to fully address these issues without complex and inaccurate rotations or increased coil complexity.
Innovation Solution
The use of two stages of dodecapole elements with specifically arranged poles and exciting coils or electrodes to produce magnetic or electric fields of 3-fold and 6-fold symmetry, allowing for the simultaneous correction of spherical aberration and 6-fold astigmatism without rotating the dodecapole elements, thereby expanding the angular aperture and improving spatial resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the angle of incidence is increased to reduce diffraction aberration, then spatial resolution improves, but the range of incident angles that can be aberration-corrected is limited by the finite thickness of multipole elements
Solution Approach 1:
The patent changes the geometric parameters of the multipole element by reducing its thickness along the optical axis. This parameter change allows a wider range of incident angles to pass through the element while maintaining aberration correction capability, thereby enabling both high spatial resolution and broad angular acceptance
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables the creation of a probe with a wider angular aperture and a smaller diameter, reducing diffraction aberration and achieving improved spatial resolution by effectively correcting both spherical aberration and 6-fold astigmatism with a simple and stable structure.
Implementation Method 1
Each dodecapole element has first through twelfth poles arranged in this order. It is assumed that an integer n can have a value from 0 to 2 (i.e., n=0, 1, 2). The exciting coils of the (4n+1)th pole and the exciting coils of the (4n+4)th pole are alternately connected in series and produce magnetic fields which are identical in absolute value but mutually opposite in sense relative to the optical axis within a plane perpendicular to the optical axis
Implementation Method 2
exciting coils installed respectively at the poles of the dodecapole elements. The exciting coils of the (4n+1)th pole and the exciting coils of the (4n+4)th pole are alternately connected in series and produce magnetic fields
Data Source
AI summary
An aberration corrector has two stages of dodecapole (12-pole) elements each of which has first through twelfth poles arranged in this order. Exciting coils of the (4n+1)th poles and the exciting coils of the (4n+4)th poles are connected with a first reversible power supply in series (where n=0, 1, 2) to produce magnetic fields which are identical in absolute value but mutually opposite in sense relative to the optical axis within a plane perpendicular to the axis. The exciting coils of the (4n+3)th poles and the exciting coils of the (4n+2)th poles are connected with a second reversible power supply in series to produce magnetic fields which are identical in absolute value but mutually opposite in sense relative to the optical axis within the plane perpendicular to the axis.