Interdigitated Axial Lens Layout for Charged-Particle Aberration Control
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Solution Overview
Problem
Conventional electrostatic lenses suffer from geometrical aberrations that hinder the precise focusing and manipulation of charged particles, particularly ions, leading to imperfect phase-space distribution at the final state, which complicates downstream ion manipulation.
Innovation Solution
An axially progressive electrostatic lens is designed with interdigitated electrodes that generate a composite electrostatic field with a progressively varying potential profile along the axial direction, reducing geometrical aberrations by spreading focusing power across the lens axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electrostatic lenses are used to focus charged particles, then focusing capability is achieved, but geometrical aberrations (spherical and positional) occur that degrade phase-space distribution
Solution Approach 1:
The lens is divided into multiple electrode segments (first group and second group of electrodes) with different potentials, allowing independent control of field regions to correct different types of aberrations separately while maintaining overall focusing capability
Solution Approach 2:
Different regions of the lens have different electrostatic field characteristics by applying different potentials to different electrode groups, creating locally optimized field distributions that reduce spherical aberration in some regions and positional aberration in others
2Manufacturing precision
If strong electrostatic fields are applied to achieve sharp focusing, then spatial resolution is improved, but spherical aberration increases due to higher order field terms
Solution Approach 1:
The lens system dynamically adjusts the potential distribution across different electrode groups to optimize the balance between focusing strength and aberration reduction, allowing the field configuration to adapt to different operating conditions and particle types
Solution Approach 2:
By changing the potential parameters applied to different electrode groups, the electrostatic field distribution is optimized to maintain strong focusing while reducing the relative strength of higher order field terms that cause spherical aberration
3Ease of manufacture
If simple two-electrode lenses are used to reduce device complexity, then ease of manufacture is improved, but aberration control and phase-space distribution quality deteriorate
Solution Approach 1:
The lens is divided into multiple electrode segments (first group and second group of electrodes) with different potentials, allowing independent control of field regions to correct different types of aberrations separately while maintaining overall focusing capability
Solution Approach 2:
The multi-electrode configuration serves multiple functions simultaneously: providing overall focusing, correcting spherical aberration, reducing positional aberration, and controlling phase-space distribution, making the lens universally applicable to different charged particle manipulation 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
The axially progressive electrostatic lens significantly improves charged particle transmission and maintains or enhances the phase-space distribution, reducing spherical and positional aberrations compared to conventional lenses.
Implementation Method 1
a first group of first electrodes configured to receive a first DC potential from a DC voltage source and generate a first electrostatic field; and a second group of second electrodes configured to receive a second DC potential from the DC voltage source different from the first DC potential and generate a second electrostatic field
Implementation Method 2
the first group and the second group are configured to generate a composite electrostatic field in the lens interior comprising a superposition of the first electrostatic field and the second electrostatic field
Implementation Method 3
When an ion propagates axially by a finite distance, dz, in the electrostatic lens, the ion's trajectory will be bent due to the radial electric force
Implementation Method 4
at least one of the first group or the second group has a geometric feature that progressively varies along the axial direction; the first group and the second group are configured to generate a composite electrostatic field in the lens interior comprising a superposition of the first electrostatic field and the second electrostatic field
Data Source
AI summary
An electrostatic lens for transporting charged particles in an axial direction includes a first group of first electrodes configured to receive a first DC potential from a DC voltage source, and a second group of second electrodes configured to receive a second DC potential from the DC voltage source different from the first DC potential. The first electrodes are interdigitated with the second electrodes. The first group and/or the second group has a geometric feature that progressively varies along the axial direction. The lens generates an axial potential profile that progressively changes along the axial direction, and thereby reduces geometrical aberrations. The lens may be part of a charged particle processing apparatus such as, for example, a mass spectrometer or an electron microscope.