Segmented GEM Foil for Ionizing Radiation Detection
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Solution Overview
Problem
Prior ionizing radiation detection devices face errors in image accuracy due to high energy electrons colliding with gas molecules, leading to erroneous signal positioning and the risk of electrical discharges, and large GEMs act as capacitors storing dangerous charges.
Innovation Solution
The design includes a converter unit with a stack of perforated accelerator plates and a GEM with strategically aligned through holes to reduce discharge risks, and the GEM's copper coatings are divided into segments to lower capacitance, ensuring accurate electron multiplication and preventing electrical discharges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a large potential difference is applied between the converter and the GEM to achieve large electron amplification, then the electron multiplication capability is improved, but the risk of electrical discharges (sparking) between the converter and the GEM increases
Solution Approach 1:
The GEM foil is divided into multiple independent segments separated by insulating barriers. This segmentation prevents electrical discharges from propagating across the entire GEM surface, allowing higher potential differences to be applied safely between the converter and GEM to achieve greater electron multiplication while maintaining system reliability
Solution Approach 2:
Insulating barriers are introduced between the converter and GEM segments to act as intermediaries that prevent direct electrical contact. These barriers allow the necessary electric field for electron multiplication to exist while blocking the harmful sparking effect, thus resolving the contradiction between multiplication capability and discharge risk
2Productivity
If high energy electrons travel laterally through the gas gap between the converter and the GEM, then electron multiplication occurs, but erroneous position signals are generated reducing image accuracy
Solution Approach 1:
The harmful lateral electron travel path is removed from the system by designing the gas gap and GEM segmentation to confine electrons to vertical trajectories only. This extraction of the erroneous lateral component allows electron multiplication to proceed efficiently while eliminating the source of position errors
Solution Approach 2:
The electric field is made non-uniform with stronger vertical components near the converter-GEM interface and weaker lateral components throughout the gas gap. This local field configuration guides electrons vertically for accurate positioning while still allowing sufficient multiplication, thus resolving the contradiction between productivity and measurement precision
3Area of stationary object
If the GEM is made large to cover the detection area, then the detection coverage is improved, but the capacitive effect increases storing dangerous charges
Solution Approach 1:
The large GEM is divided into multiple small independent segments, each with its own capacitance. This segmentation maintains the overall large detection coverage area while reducing the capacitive effect, as the total stored charge is distributed across many smaller capacitors rather than concentrated in one large capacitor
Solution Approach 2:
The electrical parameters of the GEM system are changed by introducing insulating barriers that electrically isolate different segments. This parameter change transforms the system from a single large capacitor to multiple smaller capacitors in series/parallel configuration, reducing the harmful capacitive charge storage while preserving the large physical detection area
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 enhances the accuracy of ionizing radiation detection by minimizing erroneous signals and reducing the risk of electrical discharges, while also mitigating the capacitive issues associated with large GEMs.
Implementation Method 1
Solid converters rely on the interaction of the incident photons with a solid sheet of material to generate electrons by the Compton Effect or pair production
Implementation Method 2
Solid converters rely on the interaction of the incident photons with a solid sheet of material to generate electrons by the Compton Effect or pair production
Implementation Method 3
Electrons which pass through the substrate and impact with the gas molecules in the gas-filled gap cause ionization of the gas molecules and the production of secondary electrons
Implementation Method 4
The electrical field generated in the gas in the through holes initiates electron avalanches which increase the number of electrons leaving each through hole. The number of electrons generated in the avalanche can be in the range of 100-1000 per incoming electron
Data Source
AI summary
The invention relates to a detecting unit for detecting ionizing radiation. The device comprises a converter unit for the amplification of ionizing radiation and a read-out unit, wherein the converter unit comprises a converter and a gas-electron multiplier, wherein said converter comprises a substrate with an ionizing radiation-receiving major surface and an electron-emitting major surface and a stack of accelerator plates in contact with the electron-emitting major side, wherein said stack comprises a plurality of perforated accelerator plates wherein the perforations of the perforated accelerator plates are aligned to form a matrix of blind holes.