Kingdon Mass Spectrometer Cylindrical Electrodes Decoupling Ion Motion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current electrostatic Fourier transform mass spectrometers face limitations in the duration of image current transients and mass resolution due to residual coupling of axial and transverse ion motions, which affects the coherence and precision of ion trajectories, and are difficult to evacuate efficiently.
Innovation Solution
The design incorporates a Kingdon ion trap with specially shaped sheath electrodes forming concentric cylindrical surfaces divided by parabolic gaps, allowing for independent axial oscillations and orbiting motions, enabling fine adjustments of voltages to decouple ion motions and potentially achieve coherence focusing, thus extending the duration of image current transients and improving mass resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electrostatic measuring cells are used, then the device structure is relatively simple, but the duration of image current transients is limited and mass resolution is insufficient
Solution Approach 1:
The measuring cell is divided into multiple electrode segments (first, second, third, and fourth electrode segments) arranged in a specific geometric configuration. This segmentation allows independent control of electric fields in different regions, enabling decoupling of axial and transverse ion motions while maintaining a manageable structural complexity
Solution Approach 2:
The patent introduces a specific spatial arrangement of electrodes in three-dimensional space, creating orthogonal electric field components that independently control motion in different dimensions. This dimensional approach allows decoupling of ion motions without requiring complex magnetic fields
2Reliability
If conventional electrode configurations are used, then the device is easier to manufacture, but residual coupling of axial and transverse ion motions occurs, limiting coherence and precision
Solution Approach 1:
The electrode segments are positioned asymmetrically with respect to the measurement axis, creating anisotropic electric field distributions that selectively influence axial and transverse motions differently. This asymmetric configuration enables decoupling of ion motions while maintaining manufacturability through standard electrode fabrication techniques
3Reliability
If the measuring cell is closed or partially closed, then ion trajectories are better contained, but evacuation efficiency decreases
Solution Approach 1:
The measuring cell features localized electrode segments rather than continuous closed walls. This local quality approach provides sufficient ion containment through targeted electric fields at critical regions while leaving other areas open for efficient vacuum evacuation, resolving the contradiction between trajectory containment and evacuation efficiency
4Measurement precision
If magnetic fields are used to control ion motions, then mass resolution can be improved, but the device becomes more complex and requires superconducting magnets
Solution Approach 1:
The patent replaces the mechanical/magnetic field system (superconducting magnets) with an electrostatic field system consisting of precisely arranged electrode segments. This substitution achieves equivalent or superior ion motion control through electric fields, eliminating the need for complex magnetic field generation infrastructure
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 configuration allows for efficient evacuation and optimization of image current transient duration, enhancing mass resolution and coherence focusing, leading to improved precision in mass spectrometry without the need for complex magnetic fields.
Implementation Method 1
Appropriate voltages at the sheath electrode segments generate a potential distribution between the two concentric cylindrical surfaces which forms a parabolic potential well in the axial direction for orbiting ions
Implementation Method 2
The ion clouds oscillating harmonically in the axial direction in this potential well induce image currents in suitable electrodes, from which the oscillation frequencies can be determined by Fourier analyses
Data Source
AI summary
The invention relates to measuring devices of an electrostatic Fourier transform mass spectrometer and measurement methods for the acquisition of mass spectra with high mass resolution. The measuring device includes electrostatic measuring cells according to the Kingdon principle, in which ions can, when appropriate voltages are applied, orbit on circular trajectories around the cylinder axis between two concentric cylindrical surfaces, which are composed of specially shaped sheath electrodes, insulated from each other by parabolic gaps, and can harmonically oscillate in the axial direction, independently of their orbiting motion. In the longitudinal direction, the two cylindrical surfaces of the measuring cell are divided by the parabolic separating gaps into different types of double-angled and tetragonal sheath electrode segments. Appropriate voltages at the sheath electrode segments generate a potential distribution between the two concentric cylindrical surfaces which forms a parabolic potential well in the axial direction for orbiting ions. The ion clouds oscillating harmonically in the axial direction in this potential well induce image currents in suitable electrodes, from which the oscillation frequencies can be determined by Fourier analyses.