Dual-Mode Ion Detector With Fixed-Potential Conversion Electrodes
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Solution Overview
Problem
Existing dual-mode ion detectors for mass and/or ion mobility spectrometers face challenges in reliably and sensitively detecting both positive and negative ions, often requiring complex and expensive high-voltage power supplies for switching between modes.
Innovation Solution
A dual-mode ion detector design featuring a first conversion electrode for positive ions and a second conversion electrode for negative ions, both maintained at fixed potentials, with an entrance electrode that switches between modes by applying a suitable voltage to draw ions into the detector, eliminating the need for switchable high-voltage power supplies for the conversion electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If switchable high-voltage power supplies are used for conversion electrodes to enable dual-mode detection, then the ion detector can detect both positive and negative ions, but the device complexity and cost increase significantly
Solution Approach 1:
The ion detector is divided into functionally independent sections: a first conversion electrode for positive ions, a second conversion electrode for negative ions, and an entrance electrode for mode switching. Each electrode is maintained at a fixed potential, eliminating the need for switchable high-voltage power supplies while preserving dual-mode detection capability.
Solution Approach 2:
Instead of switching the high-voltage power supplies to change detection modes, the patent inverts the approach by keeping power supplies fixed and using the entrance electrode voltage to control ion entry. This reverses the conventional switching mechanism and simplifies the power supply system.
2Adaptability or versatility
If high-voltage power supplies are switched between modes, then dual-mode detection is achieved, but the switching speed and stability deteriorate
Solution Approach 1:
The patent inverts the conventional switching approach by keeping high-voltage power supplies fixed and instead controlling mode switching through the entrance electrode voltage. This allows faster and more stable switching since low-voltage control circuits are used rather than high-voltage power supply switching.
Solution Approach 2:
The entrance electrode acts as an intermediary control element between the control electronics and the conversion electrodes. By controlling ion entry through the entrance electrode rather than directly switching conversion electrode voltages, the system achieves faster and more stable mode transitions.
3Measurement precision
If conversion electrodes are optimized for specific ion polarities, then detection sensitivity is improved, but the device complexity increases for dual-mode operation
Solution Approach 1:
The detection system is segmented into dedicated conversion electrodes: a first conversion electrode optimized for positive ion detection and a second conversion electrode optimized for negative ion detection. Each electrode can be independently optimized for its specific ion polarity while the system as a whole achieves dual-mode capability through the segmented architecture.
Solution Approach 2:
Each conversion electrode is given specialized properties tailored to its function: the first conversion electrode is optimized for positive ion conversion while the second is optimized for negative ion conversion. This local optimization of electrode characteristics enables high sensitivity for each mode without requiring the entire system to be reconfigured.
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 simplifies control electronics, reduces costs, and enhances switching speed and stability, allowing for improved sensitivity and reduced complexity in ion detection, while maintaining high sensitivity by optimizing the conversion electrodes for their respective functions.
Implementation Method 1
a first conversion electrode that is maintained, in use, at a negative potential and arranged for converting incident positive ions into secondary electrons
Implementation Method 2
a second conversion electrode that is maintained, in use, at a positive potential and arranged for converting incident negative ions into secondary positive ions and/or secondary electrons
Implementation Method 3
an entrance electrode for drawing ions into the ion detector, wherein in the first mode a negative voltage is applied to the entrance electrode to draw incoming positive ions into the ion detector
Data Source
AI summary
A dual-mode ion detector for a mass and/or ion mobility spectrometer comprising a first conversion electrode (20) that is maintained, in use, at a negative potential and arranged for converting incident positive ions (32) into secondary electrons (34), and a second conversion electrode (22) that is maintained, in use, at a positive potential and arranged for converting incident negative ions (42) into secondary positive ions (44) and/or secondary electrons (74). The detector also comprises an electron detecting surface (26) and an entrance electrode (24) for drawing ions into the ion detector. The ion detector is switchable between a first mode for detecting positive ions and a second mode for detecting negative ions.