Axial Magnetic Field Ion Source for Mass Spectrometry
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Solution Overview
Problem
Existing ion sources, such as the cross-beam EI source, suffer from significant ion loss due to ions being drawn out or defocused upon collision with the inner surfaces of the ionization chamber, leading to reduced efficiency in transferring ions to downstream devices like mass analyzers.
Innovation Solution
An ion source design that produces an electron beam coaxial with the ion beam, utilizing a magnet assembly to generate a uniform axial magnetic field and a lens assembly to focus and extract ions along the source axis, reducing ion losses and enhancing ionization efficiency by maintaining the ion beam's integrity as it enters downstream processing devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a cross-beam EI source design is used, then ionization can occur, but significant ion loss occurs due to ions being drawn out or defocused upon collision with the inner surfaces of the ionization chamber
Solution Approach 1:
The patent inverts the conventional cross-beam geometry by making the electron beam axial (coaxial with the ion beam path) rather than perpendicular. This inversion changes the spatial relationship between electron and ion beams, allowing ions to be extracted along the beam axis away from chamber surfaces, thereby reducing ion loss while maintaining ionization efficiency
Solution Approach 2:
The patent transitions from a two-dimensional cross-beam configuration to a three-dimensional axial configuration where the electron beam travels parallel to the ion extraction path. This dimensional change allows for optimized ion extraction geometry that minimizes surface collisions while maintaining effective ionization volume
2Productivity
If an axial electron beam is used, then ion beam coaxial alignment with downstream devices is achieved, but device complexity increases due to magnet assembly requirements
Solution Approach 1:
The magnet assembly serves multiple functions: it focuses the electron beam into a tight axial path, confines electrons to prevent premature collisions with chamber walls, and enables the axial beam geometry necessary for efficient ion extraction. By consolidating these functions into a single component, the patent reduces overall system complexity despite the sophisticated requirements
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 design significantly reduces ion trapping and neutralization, allowing for improved extraction and transmission of ions into downstream devices, thereby increasing the sensitivity and efficiency of the mass spectrometry system.
Implementation Method 1
a magnet assembly configured for generating a uniform axial magnetic field in the ionization chamber
Implementation Method 2
Ionization of the sample material occurs as a result of the electron beam bombarding the sample material
Implementation Method 3
a lens assembly comprising an extractor configured for directing an ion beam out from the ionization chamber along the source axis
Data Source
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AI summary
An ion source (100; 300; 600) is configured for electron ionization and produces coaxial electron and ion beams. The ion source includes an ionization chamber (208) along an axis, a magnet assembly (112; 612) configured for generating an axial magnetic field in the ionization chamber, an electron source(116), and a lens assembly (120) configured for directing the ion beam out from the ionization chamber along the axis, reflecting the electron beam back toward the electron source, and transmitting higher energy ions out from the ion source while reflecting lower energy ions toward a lens element for neutralization.