Axial Electron Impact Ion Source With Separate Ionization Regions
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Solution Overview
Problem
Traditional electron impact ion sources face challenges with ion extraction efficiency and contamination of electrodes, leading to reduced sensitivity and increased maintenance needs, particularly when using calibrants like perfluorokerosene or perfluorotributylamine, which result in decreased signal intensity over time.
Innovation Solution
The implementation of an axial electron impact ion source with separate ionization regions allows for independent control of each region's conditions, including pressure and electron beam alignment, minimizing contamination and enhancing ionization efficiency by directing molecules away from electrodes and operating under high vacuum conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional crossed-beam ion source is used, then ion extraction efficiency is low, but device structure is simple
Solution Approach 1:
The ion source is divided into separate functional regions: a first ionization region for sample molecules and a second ionization region for calibrant molecules. This segmentation allows independent optimization of each region, improving ion extraction efficiency while maintaining manageable structural complexity through modular design.
Solution Approach 2:
The patent transitions from a crossed-beam geometry to an axial geometry where the electron beam and ion beam share a common axis. This dimensional reorganization improves ion extraction efficiency by aligning the extraction field with the ion generation region, while the axial configuration actually simplifies certain structural elements compared to the crossed-beam design.
2Productivity
If axial ion source is used to improve ion extraction efficiency, then electrode contamination increases
Solution Approach 1:
By separating the ionization into distinct first and second regions, the patent prevents contamination from calibrant molecules (introduced in the second region) from reaching the extraction electrodes. The spatial segmentation creates a physical barrier that maintains electrode cleanliness while preserving high ion extraction efficiency.
Solution Approach 2:
The patent extracts the calibrant molecule introduction point from the main ionization path by placing it in a separate second ionization region. This extraction of the calibrant introduction function prevents calibrant molecules from contaminating the extraction electrodes while still allowing effective ionization of both sample and calibrant molecules.
3Productivity
If separate ionization regions are implemented, then ionization efficiency is enhanced, but device complexity increases
Solution Approach 1:
The electron beam serves multiple functions: it ionizes sample molecules in the first ionization region and calibrant molecules in the second ionization region. This multi-functionality of the electron beam system enhances overall ionization efficiency without proportionally increasing device complexity, as the same electron source and control systems serve both regions.
Solution Approach 2:
The patent combines the electron beam generation and control systems to serve both ionization regions, merging functions that could have been separate. This consolidation enhances ionization efficiency for both sample and calibrant molecules while limiting the increase in device complexity through shared components and integrated control.
4Object-affected harmful factors
If electrodes are cleaned regularly by removing the body, then contamination is reduced, but sample throughput decreases
Solution Approach 1:
The patent extracts the source of contamination (calibrant molecules) from the path to the extraction electrodes by introducing them in a separate second ionization region. This prevents contamination in the first place, eliminating the need for regular cleaning interruptions and maintaining continuous sample throughput while keeping electrodes clean.
Solution Approach 2:
The design preliminarily prevents electrode contamination by spatially separating the calibrant introduction region from the electrode area. This preliminary protective action eliminates the need for subsequent cleaning operations, maintaining both low contamination levels and continuous high sample throughput without operational interruptions.
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 configuration improves ion extraction efficiency, maintains long-term stability and sensitivity, reduces electrode contamination, and increases sample throughput, enabling more robust and cost-effective analytical performance.
Implementation Method 1
electrons are typically emitted from a heated filament and are accelerated into an ionisation volume containing sample gas molecules. Sample gas molecules are ionized by electron impact
Implementation Method 2
electrons are typically emitted from a heated filament
Implementation Method 3
one or more permanent magnets are employed to focus and guide the ionizing electron beam through the ionisation volume
Implementation Method 4
A positive voltage is applied between pusher electrode P and extraction electrode E that accelerates and focuses generated ions through a slit in the extraction electrode E
Data Source
AI summary
An electron impact ion source comprises: a first ionisation region comprising an aperture configured to receive first molecules into the first ionisation region, the first ionisation region being configured to receive an electron beam along a first axis to generate a first ion beam along the first axis from the first molecules; and a second, separate ionisation region comprising an inlet configured to receive second molecules into the second ionisation region, the second ionisation region configured to receive the electron beam along the first axis to generate a second ion beam along the first axis from the second molecules.