Gas Avalanche Detector Window Placement for Spatial Resolution
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Solution Overview
Problem
Conventional radiographic imaging devices using gas avalanche detectors face limitations in image resolution and quality due to inefficiencies in charge amplification and spatial resolution.
Innovation Solution
A gas avalanche detector with a configuration that includes a gas enclosure, an intermediate plane electrode, and collector electrodes, where the intermediate electrode generates an electric field for avalanche amplification, and the admission window is placed between the intermediate and collector electrodes to enhance charge pickup and spatial resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the admission window is placed laterally on the gas enclosure level with the sensing space, then the device complexity is reduced, but the spatial resolution and charge pickup efficiency deteriorate
Solution Approach 1:
The admission window is repositioned from a lateral position to a position between the intermediate and collector electrodes along the beam path direction. This dimensional change in window placement allows the beam to enter the amplification space at an optimized location, improving charge pickup efficiency and spatial resolution without significantly increasing device complexity.
2Reliability
If the intermediate electrode is placed closer to the collector electrode to enhance avalanche amplification, then the signal-to-noise ratio improves, but charge diffusion increases and spatial resolution deteriorates
Solution Approach 1:
The optimal distance between the intermediate electrode and collector electrode is determined by adjusting electrical parameters (electric field strength, avalanche gain) rather than simply minimizing physical distance. This allows sufficient amplification while maintaining spatial resolution by preventing excessive charge diffusion.
3Quantity of substance
If a larger gas enclosure volume is used to increase photon conversion efficiency, then the quantity of converted charges increases, but charge diffusion increases and spatial resolution deteriorates
Solution Approach 1:
The detector design creates different functional zones with optimized characteristics: a conversion zone for photon-to-charge conversion and an amplification zone for charge multiplication. This local optimization ensures efficient charge generation and amplification while maintaining spatial resolution by controlling charge diffusion in each zone.
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 the spatial resolution and signal-to-noise ratio by maximizing charge pickup and minimizing charge diffusion, resulting in higher image quality and resolution in radiographic imaging.
Implementation Method 1
the intermediate electrode being operable at an electrical potential relative to the electrical potentials of the end electrodes suitable for generating an electric field that causes the primary electrons to be multiplied by the avalanche phenomenon in the amplification space
Implementation Method 2
the amplification space also constituting a conversion space in which the incident X-ray photons are liable to be converted into electrical charges
Data Source
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AI summary
The invention relates to a gas avalanche detector for detecting and locating X-ray or gamma ray ionizing radiation in radiographic imaging, the detector comprising: a gas enclosure (10) provided with an admission window (FE) for admitting a beam (FX) of incident X-ray photons; an intermediate plane electrode (12) placed in said gas enclosure (10) between two end plane electrodes (11, 13) and held parallel to the two end plane electrodes (11, 13); the configuration of the end plane electrodes (11, 13) and of the intermediate plane electrode (12) forming an amplification space (20), the amplification space (20) also constituting a conversion space in which the incident X-ray photons (FX) are convertible into electrical charges, the electrical charges being made up of primary electrons and of corresponding ions; the intermediate electrode (12) being operable at an electrical potential relative to the electrical potentials of the end electrodes (11, 13) suitable for generating an electric field that causes the primary electrons to be multiplied by the avalanche phenomenon in the amplification space (20) in the vicinity of the intermediate electrode (12); one of the end electrodes (13) being configured as a collector electrode for picking up the electrical signals induced by the ions; and said admission window (FE) being placed level with the amplification space (20) between the intermediate plane electrode (12) and said collector electrode (13) to admit said photon beam between the intermediate plane electrode (12) and said collector electrode (13). The invention also relates to a radiographic imaging device including such a gas detector.