Interdigitated Electrode Ionization Source for Compact Devices
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Solution Overview
Problem
Existing ionization sources, such as radioactive isotopes and electric field ionization, face challenges with durability and lifetime due to potential damage from corona discharges, which limits their practicality in compact devices.
Innovation Solution
A compact ionization source is designed with interdigitated electrodes and a carbon nanotube or diamond-like coating layer, creating a large electric field and ionization volume while maintaining a narrow gap for efficient ionization and minimizing electrode damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a corona discharge is used for ionization, then ionization efficiency is improved, but electrode lifetime deteriorates due to potential damage from sparks or arcs
Solution Approach 1:
The electrodes are segmented into multiple interdigitated fingers, creating multiple narrow gaps that distribute the ionization process across many small regions. This segmentation prevents localized overheating and reduces the likelihood of spark or arc formation while maintaining high ionization efficiency through the cumulative effect of multiple gaps.
Solution Approach 2:
The electrode fingers are given specific local properties including interdigitated geometry with controlled spacing (10-100 μm) and surface treatments. These local quality enhancements create optimal electric field distribution in each gap region, enabling efficient ionization while preventing harmful discharge conditions through carefully controlled local electrode characteristics.
2Force
If a narrow gap is used between electrodes, then electric field strength is improved, but device complexity increases due to precise spacing requirements
Solution Approach 1:
The electrode structure transitions from a simple parallel plate configuration to an interdigitated finger configuration, adding a dimensional element. This interdigitated arrangement creates multiple narrow gaps in series, allowing the device to achieve high electric field strength across each gap while the overall device dimensions remain manageable and fabrication complexity is reduced through standard MEMS techniques.
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 solution extends the lifetime of ionization sources by maintaining a stable ionization process with reduced risk of electrode damage, enabling efficient ionization and downstream analysis while being compact and economically viable.
Implementation Method 1
The spacing between the first and second electrodes, preferably less than 1 mm, creates a large electric field when a potential is applied across the first and second electrodes
Implementation Method 2
The large electric field creates an ionization volume between the fingers of the first and second electrodes and ionizes a portion of the molecules occupying the ionization volume
Implementation Method 3
the carbon nanotube layer comprises a plurality of carbon nanotubes characterized by a longitudinal axis, the longitudinal axis parallel to a surface normal of the side of the first electrode
Implementation Method 4
the diamond-like coating (DLC) layer is comprised of tetrahedral amorphous carbon (ta-C)
Data Source
AI summary
A compact ionization source includes first and second electrodes, each having a plurality of fingers that are interdigitated with each other. The spacing between the first and second electrode, preferably less than 1 mm, creates a large electric field when a potential is applied across the first and second electrodes. The large electric field creates an ionization volume between the fingers of the first and second electrode and ionizes a portion of the molecules occupying the ionization volume. The interdigitated fingers of the first and second electrodes allow for a narrow gap separating the electrodes while presenting a large flow area for ionizing molecules for downstream analysis.