Bipolar Detector Electrode for Ion Mobility Resolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ion mobility spectrometers experience signal distortions due to induced image currents when measuring free-flying electrically charged particles, which reduce mobility resolution and sensitivity, and existing solutions like screen grids interfere with particle trajectories and increase production costs.
Innovation Solution
A detector electrode with a bipolar arrangement of structural elements, where neighboring elements have opposite polarities and are connected together, deflects incoming particles to hit only one polarity, allowing separate measurement and subtraction of current profiles to isolate the pure particle current, effectively suppressing image current distortions without using screen grids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a screen grid is used to reduce image current distortion, then measurement precision is improved, but device complexity and production costs increase
Solution Approach 1:
The detector electrode is segmented into multiple independently addressable pixel elements arranged in a matrix. Each pixel element can be individually controlled and measured, allowing the system to segment the detection area and process signals from different regions separately, thereby reducing the impact of image currents through differential measurement techniques.
Solution Approach 2:
The patent applies voltage to the pixel elements to dynamically control their electrical properties. By changing the voltage state of individual pixels or groups of pixels, the system can create virtual apertures and control charge distribution to compensate for image current effects without requiring physical screen grids.
2Measurement precision
If a screen grid is used to reduce image current distortion, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces the mechanical screen grid structure with an electronically controlled pixel electrode system. Instead of using physical grids that capture particles and require precise mechanical fabrication, the system uses electrical fields generated by voltage-controlled pixels to achieve the same image current compensation effect, significantly simplifying manufacturing.
Solution Approach 2:
The pixel electrode serves multiple functions: it detects particle currents, controls charge distribution to compensate for image currents, and creates virtual apertures for particle selection. This multi-functionality eliminates the need for separate screen grid components, reducing overall device complexity and manufacturing cost.
3Measurement precision
If a screen grid is used to reduce image current distortion, then measurement precision is improved, but sensitivity decreases
Solution Approach 1:
The patent employs dynamic voltage control of the pixel elements to adaptively respond to incoming particle clusters. The voltage state of pixels can be changed in real-time based on detected particle positions and densities, allowing the system to optimize both image current compensation and particle detection sensitivity simultaneously, unlike static screen grids.
Solution Approach 2:
The system uses feedback from the measured current signals to adjust the voltage state of pixel elements. By monitoring the current distribution and adjusting pixel voltages accordingly, the system can dynamically compensate for image current effects while maintaining high sensitivity to actual particle signals through closed-loop control.
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 method significantly improves mobility resolution by more than doubling the full width at half-maximum of the current curve and increases sensitivity by reducing background noise, while eliminating the need for screen grids and associated costs.
Implementation Method 1
A voltage is applied between the two groups of structural elements with different polarities so that shortly before the incoming particles impinge on the detector electrode, they are deflected in such a way that they hit only the structural elements of one polarity
Implementation Method 2
The measurement of the electric currents of free-flying electrically charged particles such as electrons or ions by a planar detector electrode is distorted by the image currents which the approaching particles induce in the detector electrode
Data Source
AI summary
The invention relates to the measurement of current profiles of free-flying ion or electron clusters which impinge on a detector electrode of a Faraday detector. The detector electrode here consists of a large number of structural elements in a bipolar arrangement, where neighboring structural elements have opposite polarities and structural elements with the same polarity are electrically connected, and a voltage is applied between neighboring structural elements so that before ions or electrons impinge on the detection electrode, they are essentially deflected onto the structural elements with one of the two polarities. If the current profiles on the structural elements of the two polarities are measured separately and subtracted from each other, a current profile which corresponds to the pure ion or electron current profile is obtained without using a screen grid.