Linear Ion Trap Axial Ejection With Simplified Power Supply
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Solution Overview
Problem
Resonance excitation ejection in mass spectrometers requires complex power supply configurations, leading to larger, heavier, and more expensive devices, and complicates the arrangement of subsequent ion optical devices.
Innovation Solution
A linear ion trap design that uses an RF voltage generator for creating an RF electric field and a DC voltage generator for ion extraction, allowing axial ejection of ions based on their mass-to-charge ratios without requiring superposed RF and AC voltages, simplifying the power supply and enabling easier arrangement of subsequent ion optical devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resonance excitation ejection is used for mass separation in a linear ion trap, then mass-resolving power is improved, but device complexity and power supply configuration become more complex
Solution Approach 1:
The invention extracts the AC voltage application from the rod electrodes and relocates it to a dedicated excitation electrode. This separation allows the rod electrodes to handle only RF voltages for ion confinement, while the excitation electrode handles AC voltages for resonance excitation, thereby simplifying the power supply configuration while maintaining mass separation capability
Solution Approach 2:
The invention segments the voltage application functions by assigning different electrodes to different voltage types: RF voltages are applied to rod electrodes for confinement, while AC voltages are applied to the excitation electrode for resonance excitation. This functional segmentation simplifies the overall power supply system architecture
2Measurement precision
If resonance excitation ejection is used for mass separation, then mass separation function is improved, but device size and weight increase
Solution Approach 1:
By extracting the excitation function to a separate electrode, the invention eliminates the need for complex superposed voltage circuits on the rod electrodes, thereby reducing overall device complexity, size, and weight while preserving mass separation capability
Solution Approach 2:
The excitation electrode serves multiple functions: it provides resonance excitation for mass separation, and can potentially serve as an additional confinement element. This multi-functionality reduces the need for separate dedicated components, thereby reducing overall device weight
3Measurement precision
If resonance excitation ejection is used, then mass separation is achieved, but cost of the device increases
Solution Approach 1:
The invention extracts the AC excitation function from the complex superposed voltage system on rod electrodes and places it on a dedicated excitation electrode with simple AC voltage application, thereby reducing power supply configuration complexity and device cost while maintaining mass separation capability
Solution Approach 2:
The excitation electrode can be implemented as a simpler, potentially disposable component that handles the complex AC excitation function, allowing the main rod electrodes to maintain their simpler RF-only configuration, thereby reducing overall system cost
4Ease of manufacture
If axial ejection is used instead of orthogonal ejection, then arrangement of subsequent ion optical devices is simplified, but mass separation capability may be compromised
Solution Approach 1:
The invention segments the ion ejection function from the mass separation function by using a dedicated excitation electrode for resonance excitation while maintaining axial ejection geometry. This allows axial ejection to proceed without compromising mass separation capability, as the excitation electrode provides the necessary resonance excitation independent of the ejection direction
Solution Approach 2:
The excitation electrode provides universal resonance excitation capability that works effectively for axial ejection geometry, making the system adaptable to simplified ion optical device arrangements while maintaining mass separation performance
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 simplified power supply configuration results in a smaller, lighter, and less expensive mass spectrometer that can perform axial ejection and mass scans efficiently, facilitating the alignment of ion optical devices and improving detection sensitivity.
Implementation Method 1
an RF voltage generator configured to apply an RF voltage to the plurality of rod electrodes and the auxiliary electrode in order to create an RF electric field within an ion-capturing space
Implementation Method 2
an extracting voltage generator configured to apply a DC voltage to the extracting electrode so that a DC electric field for ion extraction reaches the ion-capturing space
Implementation Method 3
For the mass separation within an ion trap, resonance excitation ejection is normally employed
Implementation Method 4
separating those ions according to their mass-to-charge ratios (m/z)
Data Source
AI summary
In a mass spectrometer, a linear ion trap unit (2) has an ion-capturing space formed by rod electrodes (20) surrounding a central axis (C) and an auxiliary electrode (21) provided outside an ion-ejection end of the rod electrodes or protruding from the ion-ejection end. An extracting electrode (23) is located further outside the auxiliary electrode. An RF voltage generator (50) applies RF voltages to the rod electrodes and the auxiliary electrode to create an RF electric field within the ion-capturing space. An extracting voltage generator (52) applies a DC voltage to the extracting electrode so that a DC electric field for ion extraction reaches the ion-capturing space. A controller (4) controls the RF and extracting voltage generators to eject ions from the ion-capturing space along the central axis according to their m/z by changing the RF voltage or the DC voltage when the ions are confined within the ion-capturing space.