Perforated Central Electrode for Stable Electrostatic Beam Deflection
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Solution Overview
Problem
Conventional electrostatic deflectors require high relative accuracy for voltage control to maintain angular stability, which is technically demanding due to sensitivity to residual ripple, noise, and temperature stability, making them costly and prone to precision issues.
Innovation Solution
The electrostatic deflector design includes a central electrode with openings for the electric field from deflection electrodes to penetrate, reducing field strength and sensitivity to voltage fluctuations while maintaining precise control, allowing for higher precision and stability with fewer power supplies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional deflection electrodes are connected to internal power supplies providing predefined potentials, then a defined electric field and fixed nominal potential are achieved in the centre of the deflector, but high relative accuracy for voltage control (10^-5) is required to maintain angular stability
Solution Approach 1:
A central electrode is introduced as an intermediary component between the deflection electrodes and the particle beam. This central electrode with openings shields the beam from direct exposure to the full electric field, reducing the sensitivity to voltage fluctuations while maintaining the necessary deflection precision through the modified field distribution.
Solution Approach 2:
The central electrode is designed with a porous or perforated structure containing multiple openings. This porous configuration allows the electric field to penetrate through the central electrode to deflect the beam, while simultaneously providing field shielding that reduces sensitivity to voltage drifts and fluctuations, achieving three orders of magnitude increase in deflection stability.
2Force
If opposite deflecting electrodes are set to potentials of 992 V and 1008 V to generate E = 1 V/mm field strength at 1 kV nominal potential, then beam deflection of 3.8° is achieved, but the system becomes highly sensitive to voltage drifts and fluctuations
Solution Approach 1:
The central electrode with openings is positioned beforehand to cushion or buffer the electric field's direct impact on the particle beam. This pre-positioned shielding structure reduces the transmission of voltage fluctuations to the beam, providing stability compensation before the field variations can significantly affect beam deflection.
3Ease of operation
If all deflecting electrodes are supplied with nominal potential to allow particles to pass without direction change, then zero deflection is achieved, but any voltage fluctuation directly translates to beam angle instability
Solution Approach 1:
The central electrode serves as a mediator that decouples the relationship between electrode voltage fluctuations and beam angle changes. By positioning this intermediary structure with openings in the path of both the electric field and the particle beam, it allows controlled field penetration while shielding against unwanted voltage variations, thereby stabilizing beam angle despite ease of operation requirements.
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 design achieves three orders of magnitude increase in deflection stability with reduced sensitivity to voltage drifts and fluctuations, enabling precise and robust particle beam deflection at lower costs.
Implementation Method 1
an electrical field in a transversal direction to the axis of flight is provided. The electrical field is the gradient of the potential
Implementation Method 2
The electrostatic deflector comprises at least two deflection electrodes connected to at least one power supply to supply a predefined potential
Implementation Method 3
reducing field strength and sensitivity to voltage fluctuations while maintaining precise control
Data Source
Figure 1
Figure 2a~2e
Figure 3a~4b
AI summary
Electrostatic deflector for charged particle optics comprising at least two deflection electrodes connected to at least one power supply to supply a predefined potential (Ui) to at least one of the deflection electrodes, wherein the deflection electrodes define an axis of flight for a charged particle beam and provide an electrical field in a transverse direction to the axis of flight, wherein a central electrode encloses the axis of flight, wherein the central electrode has a plurality of openings through which the electrical field of the deflection electrodes penetrates into the central electrode and deflects the charged particle beam within the central electrode.