TOF Mass Analyzer Detection Surface for Ion Beam Monitoring
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Solution Overview
Problem
Mass spectrometers with complex ion beam trajectories face challenges in maintaining precise ion beam alignment and detecting ions effectively, especially in high-resolution analyzers where strong electrostatic fields require precise beam characteristics, leading to potential beam loss and aberrations, and existing detection methods are either invasive, costly, or inefficient.
Innovation Solution
A method and apparatus for a time of flight or electrostatic trap mass analyzer that includes a detection surface within the analyzer, part of an active field-sustaining electrode, where ions are deflected onto this surface to measure charge and determine ion properties without disrupting the analyzer field, allowing for rapid monitoring and alignment of the ion beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a long and complex beam path is used in the mass analyzer to achieve high mass resolution, then mass resolution is improved, but the ion beam may be lost by collision with analyzer structure elements or suffer beam aberrations due to imprecise field maintenance
Solution Approach 1:
The invention introduces a beam monitoring capability that allows preliminary detection of the ion beam before it completes the full complex trajectory. By monitoring the beam at an intermediate point and detecting deviations early, the system can take corrective action before the beam is lost entirely, thus maintaining reliable detection while using long complex paths for high resolution
Solution Approach 2:
The invention uses an intermediary detection system that monitors the ion beam at an intermediate location within the analyzer. This intermediary monitoring point allows the beam characteristics to be assessed without requiring the beam to complete the full trajectory, enabling early detection of beam loss or aberrations while maintaining the high-resolution complex path
2Measurement precision
If strong electrostatic fields are used in the mass analyzer to achieve high mass resolution, then measurement precision is improved, but beam alignment precision requirements are exaggerated and the beam rapidly diverges from the ideal path
Solution Approach 1:
The invention implements a feedback mechanism where the intermediate beam monitoring system detects deviations from the ideal beam path caused by strong electrostatic fields. This information is fed back to adjust beam alignment in real-time, compensating for the exaggerated sensitivity to misalignment that strong fields create, thus maintaining both high resolution and practical alignment tolerances
3Loss of time
If external detectors are used to monitor the ion beam before complete traversal, then beam position and trajectory can be determined early, but the analyzer geometry may not conveniently allow ejection to the final detector until the entire flight path has been travelled
Solution Approach 1:
The invention merges the intermediate monitoring function with existing analyzer components by utilizing a detection surface that is part of an active field-sustaining electrode. This integration allows beam monitoring at an intermediate point without adding separate external detector systems or complex ejection mechanisms, reducing overall device complexity while enabling early beam characterization
4Ease of operation
If analyzer electrodes are used as temporary beam monitoring devices, then beam monitoring is achieved, but the analyzer becomes inoperable as a mass analyzer during measurement
Solution Approach 1:
The invention segments the detection function from the mass analysis function by using a dedicated detection surface on a field-sustaining electrode rather than requiring the entire electrode to be switched to monitoring mode. This segmentation allows simultaneous or rapid alternating operation of both mass analysis and beam monitoring functions, maintaining high productivity while providing easy beam monitoring capability
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
Enables precise determination of ion properties and quantity within the analyzer, improving beam alignment and mass resolution while maintaining analyzer field integrity, reducing downtime and operational costs.
Implementation Method 1
measuring a quantity representative of the charge arriving at the detection surface caused by the impinging ions
Implementation Method 2
applying a beam deflection to deflect at least some of the ions from the main flight path so that they impinge upon a detection surface
Implementation Method 3
Some designs of TOF and EST mass analyzers utilise electric fields, in some cases strong electrostatic fields, which are present along most or all the ion beam path within the analyzer
Implementation Method 4
Time of flight (TOF) mass analyzers and electrostatic trap (EST) mass analyzers may direct the ions upon lengthy and/or complex beam trajectories
Data Source
AI summary
Methods and analyzers useful for time of flight mass spectrometry are provided. A method of determining properties of ions within a time of flight or electrostatic trap mass analyzer comprises the steps of: injecting ions into the mass analyzer; causing the ions to follow a portion of a main flight path within the mass analyzer, the main flight path comprising multiple changes of direction; applying a beam deflection to deflect at least some of the ions from the main flight path so that they impinge upon a detection surface located within the mass analyzer, the detection surface comprising part of an active field-sustaining electrode of the mass analyzer; measuring a quantity representative of the charge arriving at the detection surface caused by the impinging ions; determining, from the deflection applied, properties of a trajectory upon which the ions were travelling immediately prior to deflection, and/or determining, from the quantity measured, a value representative of the number of the ions that impinged upon the detector surface; and wherein the analyzer utilises an analyzer field, the detection surface sustains the analyzer field in its vicinity, and the analyzer field in the vicinity of the detection surface is substantially non-zero.