Vacuum Measurement Device Ion Extractor Segmentation
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Solution Overview
Problem
Conventional vacuum measurement devices, such as ionization vacuum gauges and mass spectrometers, face issues with poor ion beam passage efficiency and noise interference from soft X-rays and electron-stimulated desorption ions, making it difficult to measure extremely low vacuum pressures with precision.
Innovation Solution
A vacuum measurement device design featuring a grid with an elongated ion outlet and matching ion beam passage slit, combined with an electrostatic deflector and magnetic field for precise ion beam control, reduces energy dispersion and noise interference, allowing for accurate measurement of vacuum pressures down to 10−9 Pa.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the ion extractor electrode is disposed outside the bottom surface of the grid with ground potential, then the structure is simplified and continuously formed with the vacuum vessel, but the ion beam passage efficiency becomes poor and noise signals increase
Solution Approach 1:
The ion extractor electrode is divided into multiple segments (first ion extractor electrode and second ion extractor electrode) positioned at different locations. This segmentation allows each electrode segment to independently extract ions from different regions of the grid, improving overall ion beam passage efficiency while maintaining structural simplicity through modular design.
Solution Approach 2:
The ion extractor electrodes are positioned not only outside the bottom surface but also inside the grid structure at specific locations. This multi-dimensional positioning strategy enables comprehensive ion extraction from various spatial regions, enhancing ion beam passage efficiency without requiring a complex single-structure design.
2Ease of manufacture
If the ion extractor electrode is disposed outside the bottom surface of the grid, then the electrode can be continuously formed with the vacuum vessel, but soft X-rays and ESD ions incident on the collector generate noise signals
Solution Approach 1:
The harmful effects of soft X-rays and ESD ions are addressed by extracting only the useful ion beam signal while separating it from the noise sources. The ion extractor electrodes are strategically positioned to extract ions before they can be contaminated by soft X-rays and ESD ions that incident on the collector, thereby eliminating noise signals while maintaining ease of manufacture through continuous formation with the vacuum vessel.
Solution Approach 2:
The ion extractor electrodes serve as intermediary elements between the grid and the collector, selectively extracting ions while preventing soft X-rays and ESD ions from reaching the collector. This intermediary positioning resolves the contradiction by blocking harmful factors while allowing continuous formation with the vacuum vessel structure.
3Device complexity
If a small hole is used in the ion extractor, then the structure is simple, but the ion passage efficiency is poor; if the hole is enlarged, then ion passage efficiency improves, but noise from soft X-rays and ESD ions increases
Solution Approach 1:
Instead of using a single large hole or a simple small hole, the ion extractor structure employs multiple electrode segments positioned at different locations. This segmentation allows the system to achieve high ion passage efficiency equivalent to a large opening while maintaining the structural simplicity of smaller individual openings, as each segment can be optimally sized and positioned.
Solution Approach 2:
The solution moves from a single-dimension hole size trade-off to a multi-dimensional configuration involving multiple electrode segments at different positions. This dimensional change allows the system to achieve high ion passage efficiency through spatial distribution rather than relying on a single large opening, thereby avoiding noise from soft X-rays and ESD ions.
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 design enhances ion passage efficiency and reduces noise, enabling precise measurement of low vacuum pressures without the need for expensive equipment, and allows for multi-functional analysis as both a mass spectrometer and leak detector.
Implementation Method 1
electrons emitted from the electron source ionize gas molecules flying into the grid (10)
Implementation Method 2
the obtained ions are extracted as an ion beam (100) from an ion outlet (11) of the grid by an ion extractor electrode (30)
Implementation Method 3
combined with an electrostatic deflector and magnetic field for precise ion beam control
Implementation Method 4
the extracted ion beam (100) is led to a magnetic field space, and the ions are separated in accordance with a mass-to-charge ratio using Lorentz's force generated when the ions travel the magnetic field space
Data Source
AI summary
A vacuum measurement device includes a grid (10) and an electron source (20) provided inside a vacuum vessel, and an ion beam (100) extracted outside the grid is captured by an ion collector (40) and is converted into a current signal. The grid (10) is a grid-shaped cylinder, and an ion outlet (11) is opened and elongated in the longitudinal direction along the side surface of the grid (10). The vacuum measurement device includes a primary ion collector (40) capturing specific ions and a secondary ion collector (50) capturing other ions. The gas molecule density of the ion source is obtained from a total current of the primary and secondary ion collectors, and a ratio of the gas molecule density of the specific ions relative to the gas molecule density is obtained from a ratio of the current of the primary ion collector (40) relative to the total current.