Monocrystalline Silicon Carbide Grids for Radiation Detection
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Solution Overview
Problem
Traditional radiation detection systems using silicon grids face issues with radiation occlusion, mechanical reliability, and susceptibility to damage due to the material's weakness and low hardness, leading to reliability and performance problems.
Innovation Solution
The development of monocrystalline silicon carbide grids with a support frame and grid portion, featuring a high open area fraction and rib aspect ratio, which are integrated to enhance radiation transmission and mechanical strength, while maintaining low radiation absorption and scattering properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silicon monocrystal grids are used with thick ribs to ensure mechanical strength, then the grid can support pressure differentials, but the open area fraction decreases and radiation transmission is occluded
Solution Approach 1:
The patent changes the material parameter from silicon to silicon carbide, which has superior mechanical properties including higher strength and hardness. This allows the grid ribs to be made thinner while maintaining the required mechanical strength, thereby increasing the open area fraction and reducing radiation occlusion.
Solution Approach 2:
The patent employs silicon carbide as a composite material that combines the benefits of high mechanical strength with low radiation absorption and scattering properties. This composite material enables the grid to achieve both structural integrity and high radiation transmission efficiency.
2Ease of manufacture
If silicon monocrystal grids are fabricated using crystallographic face wet etching, then the grid structure can be formed, but the ribs are subject to twisting and reliability issues arise
Solution Approach 1:
The patent changes the material parameter from silicon to silicon carbide, which has higher hardness and mechanical stability. This material substitution eliminates the twisting and reliability issues associated with silicon grids while maintaining compatibility with standard fabrication processes.
3Ease of manufacture
If silicon monocrystal grids are used, then the grid can be fabricated and installed, but the low hardness makes the grid easily scratched and susceptible to catastrophic failures
Solution Approach 1:
The patent changes the material parameter from silicon to silicon carbide, which has significantly higher hardness. This increase in hardness provides excellent scratch resistance and prevents catastrophic failures while maintaining ease of fabrication through established semiconductor manufacturing processes.
4Strength
If thick ribs are used in silicon grids to ensure mechanical strength, then the grid can support pressure, but radiation transmission is excessively occluded
Solution Approach 1:
The patent changes the material parameter from silicon to silicon carbide, which has higher strength-to-density ratio. This allows the grid ribs to be made thinner while maintaining pressure support capability, thereby reducing radiation occlusion and improving transmission efficiency.
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 monocrystalline silicon carbide grids provide improved radiation detection systems with increased strength, heat conductance, and resistance to damage, supporting high-pressure differentials and harsh environments, thus enhancing the performance and reliability of radiation detection systems.
Implementation Method 1
maintaining low radiation absorption and scattering properties
Implementation Method 2
maintaining low radiation absorption and scattering properties
Implementation Method 3
increased strength, heat conductance
Data Source
AI summary
Disclosed here are monocrystalline silicon carbide grids and radiation detections systems comprising such grids. Specifically, a grid comprises a support frame and a grid portion. The support frame is used for installing and supporting the grid in a detection system. The grid portion comprises a plurality of ribs, which defines a plurality of grid openings. The grid portion is used to support various components (e.g., a membrane) while allowing radiation transmission through the grid. For example, the grid portion can support the pressure up to 2 bars. The open area fraction of the grid portion can be at least 50%, or even at least 90%. The grid portion is integrated with the support frame forming monocrystal silicon carbide (e.g., 4H—SiC polymorph). In some examples, the primary surface of the grid is oriented within 8° of the crystallographic c-axis planes of the monocrystal.