Ion Mirror Mass Analyzer with Arcuate Focusing Lenses
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Solution Overview
Problem
Conventional time-of-flight (TOF) mass spectrometers face challenges in achieving high mass resolving power (RP), high transmission, wide mass range, compactness, and reduced cost for selecting ions, particularly due to limitations in ion focusing and transmission efficiency.
Innovation Solution
The method involves using an analyzer with two opposing ion mirrors, each with inner and outer field-defining electrode systems, applying specific voltages to constrain and deflect ions, and employing arcuate focusing lenses to manage ion divergence and separation, enabling selective ejection of ions of interest while maintaining high mass RP and transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the flight path length is increased to achieve high mass resolving power, then mass resolution is improved, but instrument size and manufacturing cost increase
Solution Approach 1:
The patent transforms the linear flight path into a multi-dimensional folded path using ion mirrors. Ions travel back and forth between opposing mirrors, creating an extended effective flight path within a compact physical footprint. This dimensional transformation allows high mass resolution without proportionally increasing instrument volume.
Solution Approach 2:
The ion mirrors are positioned to create nested flight paths where ions oscillate between mirrors, effectively nesting multiple flight path segments within the same physical space. This allows the instrument to achieve long flight path equivalent length while maintaining compact dimensions.
2Measurement precision
If conventional TOF analyzers are used to achieve high mass resolving power, then mass resolution is improved, but ion transmission efficiency deteriorates
Solution Approach 1:
Arcuate focusing lenses are positioned at strategic locations within the analyzer to apply focusing forces to ions before they complete their full oscillation cycles. This preliminary focusing action maintains ion beam coherence and prevents ion loss throughout the extended flight path, ensuring high transmission efficiency is maintained even as flight path length increases for high mass resolution.
3Measurement precision
If arcuate focusing lenses are applied to constrain ion divergence, then ion focusing is improved, but device complexity increases
Solution Approach 1:
Arcuate focusing lenses are activated periodically rather than continuously, with voltages applied in synchronized cycles that correspond to ion oscillation periods. This periodic activation maintains ion focusing throughout the extended flight path while keeping the system relatively simple, as the same lenses are reused in repeating cycles rather than requiring continuous complex adjustments.
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 approach allows for efficient selection and separation of ions with high mass resolving power and wide mass range, achieving compact and cost-effective ion selection while minimizing ion loss, thereby overcoming the limitations of conventional TOF mass analyzers.
Implementation Method 1
two opposing reflectors or mirrors direct charged particles repeatedly back and forth between the reflectors or mirrors
Implementation Method 2
Many examples of charged particle mirrors or reflectors have been described
Implementation Method 3
constraining the arcuate divergence from the main flight path of ions of interest by applying one set of voltages to one or more of the sets of electrodes adjacent the main flight path
Implementation Method 4
Time of flight (TOF) mass spectrometers are widely used to determine the mass to charge ratio of charged particles on the basis of their flight time along a path
Data Source
AI summary
A charged particle analyzer apparatus comprising two opposing ion mirrors each mirror comprising inner and outer field-defining electrode systems elongated along an axis z, the outer system surrounding the inner, whereby when the electrode systems are electrically biased the mirrors create an electrical field comprising opposing electrical fields along z; and at least one arcuate focusing lens for constraining the arcuate divergence of a beam of charged particles within the analyzer while the beam orbits around the axis z, the analyzer further comprising a disc having two faces at least partly spanning the space between the inner and outer field defining electrode systems and lying in a plane perpendicular to the axis z, the disc having resistive coating upon both faces. A mass spectrometer system comprising a plurality of the charged particle analyzers arranged as a parallel array.