Ion Trap Electrode Curvature for Balanced RF Fields
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Solution Overview
Problem
Ion trap devices face challenges with non-linear electro-magnetic field characteristics due to ejection slots, leading to unbalanced centerline potentials that affect ion injection efficiency and mass bias during analysis.
Innovation Solution
The implementation of geometric surface shaping on ion trap electrodes, specifically reducing the radius of curvature of X electrodes relative to Y electrodes, and applying balanced RF signals to compensate for non-linear field components, resulting in a minimal centerline RF potential and improved linear field characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If ejection slots are added to the ion trap electrodes to enable mass-selective ejection of ions, then ion trap functionality is improved, but non-linear field characteristics are introduced that degrade field linearity
Solution Approach 1:
The patent applies different geometric properties to different electrodes: X electrodes have a first geometric property (e.g., larger radius of curvature) while Y electrodes have a second geometric property (e.g., smaller radius of curvature). This local differentiation compensates for the non-linear field components introduced by ejection slots, restoring field linearity while maintaining the functionality of mass-selective ejection.
2Manufacturing precision
If electrode geometric properties are modified to compensate for non-linear field components, then field linearity is improved, but centerline potential balance is degraded
Solution Approach 1:
The patent introduces counterbalancing geometric properties to different electrodes. By giving X and Y electrodes different geometric properties (radii of curvature), the non-linear field components are compensated in a way that maintains centerline potential balance. The asymmetric geometry acts as a counterweight to the field distortions, simultaneously achieving both field linearity and potential balance.
3Manufacturing precision
If asymmetric electrode geometry is implemented to reduce non-linear field components, then field linearity is improved, but device complexity increases
Solution Approach 1:
The patent modifies specific geometric parameters of the electrodes, particularly the radius of curvature, to compensate for non-linear field components. By changing these physical parameters during the manufacturing design phase, field linearity is improved without requiring complex active control systems or additional components, thus managing device complexity while achieving the desired field characteristics.
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 approach minimizes non-linear field components and achieves a balanced centerline potential, enhancing ion trap performance by improving ion injection efficiency and reducing mass bias, thereby optimizing analysis procedures.
Implementation Method 1
a first radio-frequency signal is applied to the X electrodes which effects trapping of injected ions within the ion trap. Similarly, a second radio-frequency signal is applied to the Y electrodes which effects trapping of injected ions within the ion trap
Implementation Method 2
the shape of the X electrodes is selected so that the radius of curvature of the X electrodes is reduced with respect to the radius of curvature of the Y electrodes
Data Source
AI summary
A system and method are disclosed for effectively compensating for non-linear field components created by a field distortion feature in a quadrupolar ion trap, compensation provided by a geometric surface shaping which reduces the non-linear field components and creates a minimal centerline radio-frequency potential in the ion trap. The ion trap includes a centerline that passes longitudinally through a trapping volume inside of the ion trap, a pair of Y electrodes with inner Y electrode surfaces that are approximately parallel to the centerline, and a pair of X electrodes with inner X electrode surfaces that are approximately parallel to the centerline. The X electrodes have one or more ejection slots through which trapped ions are ejected from said ion trap. The inner Y electrode surfaces each have a Y radius of curvature, and the inner X electrode surfaces each have an X radius of curvature. The X radius of curvature is selected to be smaller than the Y radius of curvature. A balanced centerline potential is provided at the centerline of the ion trap.