Stigmator Adjustment in Particle Beam Apparatus
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Solution Overview
Problem
Manual adjustment of stigmators in particle beam apparatuses is time-consuming and requires expertise, often resulting in improper alignment of the quadrupole field, leading to unwanted deflections and image movement issues.
Innovation Solution
A fully automated method for adjusting the stigmator, involving the acquisition of multiple images at different quadrupole field strengths to determine optimal settings for the field generators, ensuring precise alignment and minimizing image displacement, without requiring specific information about the particle beam apparatus or its properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual adjustment of the stigmator is performed, then the quadrupole field can be aligned to the particle beam, but the adjustment process is time-consuming and requires expertise
Solution Approach 1:
The system performs self-adjustment by automatically acquiring images at different field strengths, calculating image displacements, and determining optimal stigmator settings without human intervention. The controller autonomously completes the entire adjustment process from image acquisition to parameter optimization.
Solution Approach 2:
The manual mechanical adjustment process is replaced by an automated control system that uses image processing algorithms and mathematical calculations to determine optimal settings, substituting human operator actions with computational methods.
2Measurement precision
If manual adjustment of the stigmator is performed, then the quadrupole field can be aligned, but the adjustment requires experienced operators
Solution Approach 1:
The system performs self-adjustment by automatically acquiring images at different field strengths, calculating image displacements, and determining optimal stigmator settings without human intervention. The controller autonomously completes the entire adjustment process from image acquisition to parameter optimization.
Solution Approach 2:
The manual mechanical adjustment process is replaced by an automated control system that uses image processing algorithms and mathematical calculations to determine optimal settings, substituting human operator actions with computational methods.
3Ease of operation
If the quadrupole field is not properly aligned, then the stigmator adjustment becomes simpler, but unwanted beam deflection occurs
Solution Approach 1:
The system uses image displacement measurements as feedback to iteratively determine optimal stigmator settings. By measuring how images shift at different field strengths and using this information to calculate the required adjustment, the system ensures proper alignment while maintaining operational simplicity.
Solution Approach 2:
The system performs preliminary alignment by acquiring images at multiple field strengths before final optimization. This preliminary data collection enables accurate calculation of image displacements and determination of optimal settings in subsequent steps.
4Manufacturing precision
If the stigmator excitation is varied, then the astigmatism can be corrected, but image movement occurs
Solution Approach 1:
The system uses image displacement measurements as feedback to iteratively determine optimal stigmator settings. By measuring how images shift at different field strengths and using this information to calculate the required adjustment, the system ensures proper alignment while maintaining operational simplicity.
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
The method enables high-accuracy, high-speed automated adjustment of the stigmator, ensuring proper alignment of the quadrupole field and reducing image displacement to less than a predetermined limit, thereby improving the stability and precision of the particle beam system.
Implementation Method 1
a stigmator in a particle beam apparatus provides a quadrupole field acting analog to a cylinder lens
Implementation Method 2
The charged particle beam traverses a quadrupole field generated by energizing at least four field generators of the stigmator
Data Source
AI summary
A method of adjusting a stigmator in a particle beam apparatus comprises directing a particle beam onto a sample wherein the particle beam traverses a quadrupole field 37 generated by energizing at least four field generators of the stigmator; acquiring first and second images of the sample at different field strengths of the quadrupole field while energizing the at least four field generators according to a first setting of a plurality of settings; acquiring third and fourth images of the sample at different field strengths of the quadrupole field 37 while energizing the at least four field generators according to a second setting of the plurality of settings; determining a plurality of image displacements based on the first, second, third and fourth images; determining an optimum setting of the at least four field generators based on the plurality of image displacements and the plurality of settings.