Multi-Reflection Time-of-Flight Analysis With Drift-Focused Zoom Mode
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Solution Overview
Problem
The resolution of multi-reflection time-of-flight (MR-ToF) analysers is limited by the length of the ion flight path and arrival time spread of ions at the detector, with time-of-flight perturbations caused by reflections at the deflector severely affecting resolving power.
Innovation Solution
A method for operating MR-ToF analysers in a 'zoom' mode, where ions complete an odd number of cycles with zigzag paths between ion mirrors, using deflectors to reverse drift direction velocity in a controlled manner to cancel out time-of-flight perturbations, allowing for high resolution operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ions complete multiple cycles in the analyser to increase the ion flight path length, then the resolution is improved, but the arrival time spread of ions at the detector increases due to time-of-flight perturbations from deflector reflections
Solution Approach 1:
The patent converts the harmful time-of-flight perturbations caused by deflector reflections into a beneficial effect by using a second deflector to introduce equal and opposite perturbations. This cancels the harmful effects while maintaining the extended ion flight path through multiple cycles, thereby improving resolution without proportionally increasing arrival time spread
Solution Approach 2:
The patent applies preliminary anti-action by pre-calculating and pre-applying compensating voltage sequences to the second deflector that anticipate and counteract the time-of-flight perturbations before they affect the ion arrival times. This allows the system to maintain high resolution while minimizing arrival time spread
2Measurement precision
If periodic lenses are used to focus the ion beam for multiple cycles, then the ion flight path length increases and resolution improves, but the device complexity increases
Solution Approach 1:
The patent extracts the focusing function from complex periodic lens systems and replaces it with a simpler deflector-based approach. By using deflectors to reverse ion drift direction and create multiple cycles, the system achieves the same resolution improvement without requiring complex lens assemblies, thereby reducing device complexity
Solution Approach 2:
The patent substitutes the mechanical/optical lens system with an electromagnetic deflector system. Instead of using physical lenses to focus and redirect the ion beam through multiple cycles, the system uses electric fields from deflectors to achieve the same effect, simplifying the overall device architecture
3Object-generated harmful factors
If the ion beam is allowed to spread out broadly in the drift direction, then space charge effects are reduced, but the arrival time spread increases
Solution Approach 1:
The patent applies periodic action by using periodic voltage sequences on the deflectors to repeatedly reverse the ion drift direction. This creates multiple oscillating cycles where ions traverse the drift region repeatedly, effectively increasing the flight path length while maintaining beam coherence. The periodic deflection ensures that even with broad beam spread, ions remain confined and arrive with minimal time spread
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 method increases the ion path length within the analyser, reducing arrival time spread and enhancing resolving power while maintaining drift focus, enabling seamless switching between normal and zoom modes.
Implementation Method 1
a deflector located in proximity with the first end of the ion mirrors... using the deflector to reverse the drift direction velocity of the ions
Implementation Method 2
two ion mirrors spaced apart and opposing each other in a first direction X... ions make multiple reflections in the X-direction between two ions mirrors
Implementation Method 3
their mass to charge ratio (m/z) is determined from their drift time through the analyser
Data Source
AI summary
Systems, methods, and computer-readable media described provide multi-reflection time-of-flight analyser (e.g. of a type in which the ion beam is allowed to spread out relatively broadly) and methods for use in a zoom mode, in which time-of-flight perturbations induced by reflections at the deflector are cancelled out or removed, such that they do not give rise to a significant increase in the arrival time spread of ions at the detector. This accordingly facilitates high resolution operation of the analyser in the zoom mode. Furthermore, this is done in a way which allows the analyser to remain drift focused, which in turn means that the analyser can be straightforwardly and seamlessly switched between its normal mode of operation and the zoom mode of operation.