Curved Isochronous Ion Interface for Multi-Reflecting TOF Mass Spectrometers

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Solution Overview

Problem

Multi-reflecting time-of-flight mass spectrometers face limitations in resolving power and sensitivity due to ion injection aberrations and initial ion packet parameters, particularly when using ion trap converters, which introduce time and energy spread that degrade mass spectral resolution.

Innovation Solution

The implementation of a spatially isochronous energy filter and curved ion interfaces that allow ions to be injected and extracted around the edges of ion mirrors, reducing aberrations and improving ion packet parameters, combined with a gas-filled ion trap for generating ion packets and delayed extraction to enhance mass analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If ion trap converters are used to generate ion packets, then ion accumulation and delayed extraction are improved, but time and energy spread increase causing degraded mass spectral resolution

Engineering Contradiction:
Improveion accumulationVSAvoidmass spectral resolution
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

A curved isochronous ion interface is introduced as an intermediary component between the ion trap converter and the multi-reflecting TOF analyzer. This interface acts as a mediator that transforms ion packets with large time and energy spread into focused ion packets, thereby resolving the contradiction between ion accumulation capability and mass spectral resolution.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The curved isochronous ion interface changes the trajectory parameters of ions through its curved geometry, transforming divergent ion packets into focused packets. This parameter transformation compensates for the time and energy spread introduced by the ion trap, improving mass spectral resolution while preserving ion accumulation capability.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If ions are injected directly into the multi-reflecting TOF analyzer, then device complexity is reduced, but injection aberrations increase reducing resolving power

Engineering Contradiction:
Improveanalyzer structureVSAvoidresolving power
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The curved isochronous ion interface serves as an intermediary that corrects injection aberrations without requiring complex modifications to the multi-reflecting TOF analyzer structure. This mediator component focuses ions before they enter the analyzer, improving resolving power while maintaining relative structural simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If conventional ion interfaces are used, then energy filtering is not achieved, but energy spread remains high reducing sensitivity

Engineering Contradiction:
Improveenergy spreadVSAvoidsensitivity
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The curved isochronous ion interface performs multiple functions simultaneously: it focuses ions spatially, filters by energy, and reduces time spread. This multi-functionality achieves energy filtering capability without requiring separate filtering components, thereby improving sensitivity while maintaining instrument compactness.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 significantly improves the resolving power and sensitivity of multi-reflecting time-of-flight mass spectrometers by minimizing injection aberrations and energy spread, enabling higher order time-of-flight focusing and full mass range measurements.

Implementation Method 1

The interface comprises a first electrostatic sector field, a second electrostatic sector field, and a third electrostatic sector field

Methodology Applied
Scientific EffectElectrostatic field: Electric Field

Implementation Method 2

a first ion packet generated by a pulsed ion source is passed around an edge of a first ion mirror by a first isochronous curved ion interface

Methodology Applied
Scientific EffectIon deflection: Lorentz Force

Implementation Method 3

Ions are reflected between the ion mirrors while slowly drifting in the direction of elongation of the ion mirrors

Methodology Applied
Scientific EffectIon reflection: Reflection

Implementation Method 4

multi-reflecting time-of-flight mass spectrometer for high resolution and full mass range measurements

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Data Source

PatentEP1866951B1Multi-reflecting time-of-flight mass spectrometer with isochronous curved ion interface
Publication Date: 2018.01.17 LECO CORP
  • EP1866951B1 patent drawingFigure 1A~1C
  • EP1866951B1 patent drawingFigure 2
  • EP1866951B1 patent drawingFigure 3A~3B

AI summary

The present invention relates generally to a multi-reflecting time-of-flight mass spectrometer (MR TOF MS). To improve mass resolving power of a planar MR TOF MS (11), a spatially isochronous and curved interface (21) may be used for ion transfer in and out of the MR TOF analyzer (11). One embodiment comprises a planar MR TOF MS (11) with periodic lenses (14) in the field-free space, a linear ion trap (17) for converting ion flow into pulses and a C-shaped isochronous interface made of electrostatic sectors. The interface (21) allows transferring ions around the edges and fringing fields (13) of the ion mirrors (12) without introducing significant time spread. The interface (21) may also provide energy filtering of ion packets. The non-correlated turn-around time of ion trap converter (17) may be reduced by using a delayed ion extraction from the ion trap and excessive ion energy is filtered in the curved interface (21).