Ion Filter for Gas Detector Position Resolution
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Solution Overview
Problem
Gas detectors using gas electron multipliers face challenges in preventing positive ion feedback while maintaining electron transmittance, leading to deteriorated position resolution due to electric fields generated by positive ions and the E×B effect in magnetic fields.
Innovation Solution
An ion filter with a three-layer structure, comprising an insulating substrate and conductive layers on both surfaces, featuring through-holes with expanding apertures and a high hole-area ratio, is used to prevent positive ion feedback while allowing electron transmittance by controlling the line widths and angles of the conductive layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If wire electrodes are used to prevent positive ion feedback, then positive ion feedback is suppressed, but the E×B effect distorts electron trajectories and deteriorates position resolution
Solution Approach 1:
The gas detector is divided into functional regions separated by the ion filter structure. The ion filter with its through-holes segments the detector volume, allowing electrons to pass through while blocking positive ions, thus preventing ion feedback without affecting electron measurement trajectories.
Solution Approach 2:
The ion filter acts as an intermediary structure between the electron multiplier and the detection region. It mediates the interaction between electrons and positive ions by allowing electrons to pass through its through-holes while blocking positive ions, thus preventing ion feedback without introducing wire electrodes that would cause E×B effects.
2Object-generated harmful factors
If conventional ion filtering structures are used, then positive ion feedback is prevented, but electron transmittance is reduced
Solution Approach 1:
The ion filter employs a porous structure with through-holes that have specific dimensions and distributions. This porous design allows electrons to pass through freely while the conductive layers and hole geometry prevent positive ion feedback, thus maintaining high electron transmittance while blocking harmful ions.
Solution Approach 2:
The ion filter structure has different properties at different locations: the through-holes allow electron passage while the conductive layers and overall geometry provide ion blocking. This local differentiation of properties enables selective transmission of electrons while preventing positive ion feedback.
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 ion filter effectively suppresses positive ion feedback without reducing electron transmittance, thereby improving the position resolution of gas detectors, especially in high magnetic fields.
Implementation Method 1
multiply electrons by the avalanche effect using a gas electron multiplier having a large number of through-holes
Implementation Method 2
Electrons are emitted from gas atoms by the photoelectric effect of radiation
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
An ion filter (1) used for a gas detector (100) is provided. The ion filter (1) has an insulating substrate (11), a first conductive layer pattern (12) formed on one main surface of the insulating substrate (11), a second conductive layer pattern (13) formed on the other main surface of the insulating substrate (11), and a plurality of through-holes (30) formed along the thickness direction of the insulating substrate (11). The one main surface of the insulating substrate (11) is disposed on the upstream side in the movement direction of electrons in the gas detector (100). The other main surface of the insulating substrate (11) is disposed on the downstream side in the movement direction of electrons in the gas detector. The first conductive layer pattern (12) has a line width (W12) thicker than the line width (W13) of the second conductive layer pattern (13).