Toroidal Ion Trap Electrode Layout for High-Capacity Mass Spectrometry
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Solution Overview
Problem
Conventional ion traps face challenges with high ion charge and sensitivity due to the space charge problem, which limits the detection of low ion concentrations and affects mass resolution and sensitivity in mass spectrometry.
Innovation Solution
The design features a ring-shaped ion trap with radially inner and outer disk-shaped ring electrodes that create a circular ion storage cell, allowing for increased ion capacity and reduced space charge density, while maintaining high mass resolution and sensitivity through a circular geometry that suppresses non-linear field sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional Paul trap geometry is used, then device complexity is reduced, but maximum ion charge capacity is limited due to space charge problem
Solution Approach 1:
The ring electrode is segmented into multiple disk-shaped ring electrodes arranged radially (inner and outer disks), creating a modular structure that increases ion capacity while maintaining manageable complexity through repetitive units
Solution Approach 2:
The ion trap transitions from a conventional linear/quadrupole geometry to a toroidal/dimensional configuration with radial disk electrodes, utilizing three-dimensional space more efficiently to increase ion capacity by over five times
2Quantity of substance
If ion trap volume is increased to reduce space charge, then space charge density decreases, but mass resolution may deteriorate due to non-linear field sections
Solution Approach 1:
The disk-shaped ring electrodes create localized quadrupole field regions with controlled field homogeneity, ensuring that each local region maintains linear field characteristics necessary for mass resolution while the overall trap volume is expanded
Solution Approach 2:
The electrode geometry parameters (radial disk configuration, spacing, and dimensions) are optimized to maintain field linearity across the expanded volume, preventing the degradation of mass resolution that typically occurs with larger trap volumes
3Ease of manufacture
If conventional hyperbolic end cap electrodes are used, then ease of manufacture is improved, but crosstalk currents occur between end cap and ring electrode
Solution Approach 1:
The end cap electrodes are designed with spherical curvature rather than hyperbolic geometry, which fundamentally changes the field distribution to eliminate crosstalk currents while remaining compatible with conventional manufacturing techniques for spherical components
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 significantly enhances the maximum ion charge capacity by over a factor of five compared to conventional Paul traps, reduces space charge, and maintains high sensitivity and mass resolution, enabling the detection of low ion concentrations effectively.
Implementation Method 1
Through the HF storage signal, an electrical field (quadrupole field) is created in the ion trap, which enables it to store ions or charged particles in a stable manner in the ion trap
Implementation Method 2
For the detection of ions, measurement signals produced at the end cap electrodes can be used which are produced by mirror charges
Data Source
Figure 1~3
AI summary
The invention concerns an ion trap (2), comprising: a first ring-shaped end cap electrode (4a) and a second ring-shaped end cap electrode (4b), between which is formed a ring- shaped ion storage cell (5), as well as a plurality (N) of radially inner disk-shaped ring electrodes (E1,i) and a plurality (N) of radially outer disk-shaped ring electrodes (E2,i), which delimit the ring-shaped ion storage cell (5). The invention also relates to a mass spectrometer (1) that has such an ion trap (2) as well as a control device (3) that is designed to actuate the disk-shaped ring electrodes (E1,i, E2,i) and the end cap electrodes (4a, 4b) for the storage, selection, excitation and/or detection of ions (6) in the ring-shaped ion storage cell (5).