Cathode ASG Carrier for Spectral CT Photon Detector
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Solution Overview
Problem
Spectral CT imaging systems require photon counting detectors with high count rate capabilities, but existing edge-on photon counting detectors face limitations in maximizing count rate due to the distance between the cathode and anodes and the thickness of the converter, which affects the detector's ability to effectively handle incoming x-ray photons.
Innovation Solution
A cathode with outwardly extending plates acts as both an anti-scatter grid and a carrier for the detector components, minimizing the distance between the cathode and anodes while ensuring sufficient x-ray absorption and mechanical stability, using conductive materials like tungsten and lead alloys for the plates and semiconductor materials like CZT for the converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the distance between the cathode and anodes is minimized to improve count rate, then the detector's ability to handle high count rates is improved, but the mechanical stability and alignment precision become more difficult to maintain
Solution Approach 1:
The cathode is merged with the ASG by integrating the ASG plates into the cathode structure, creating a unified component that eliminates alignment issues between separate cathode and ASG elements. This integration allows the minimal cathode-anode distance to be achieved while maintaining structural stability through the combined design.
Solution Approach 2:
The cathode serves multiple functions simultaneously: it acts as the electron source, provides mechanical support for the ASG plates, and forms part of the detector's structural framework. This multi-functionality reduces the number of separate components, simplifies assembly, and enables closer spacing between cathode and anodes while maintaining alignment precision.
2Reliability
If the converter thickness is increased to improve photon stopping capability, then the detection efficiency is improved, but the electron drift time increases and count rate capability decreases
Solution Approach 1:
The converter thickness is optimized to a specific range that balances photon stopping capability with electron drift time considerations. By carefully selecting the thickness parameter, the detector achieves sufficient detection efficiency while maintaining fast electron collection speeds necessary for high count rate operation.
3Reliability
If a separate ASG is used to reduce scattered radiation, then the image quality is improved, but the device complexity and alignment requirements increase
Solution Approach 1:
The ASG is merged with the cathode structure, integrating the anti-scatter function into the existing cathode component. This eliminates the need for a separate ASG assembly and its associated alignment requirements, while still providing effective scattered radiation rejection through the integrated ASG plates.
Solution Approach 2:
The cathode structure is given multiple functions: it serves as the electron-emitting cathode, provides mechanical support, and incorporates ASG functionality through integrated plates. This multi-functional design eliminates the need for separate ASG components, reducing overall device complexity and alignment requirements while maintaining image quality.
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 detector's ability to count x-ray photons efficiently by aligning the cathode plates with incoming photons, reducing scattered radiation interaction and improving mechanical stability, thereby increasing the detector's count rate and structural integrity.
Implementation Method 1
Incoming x-ray photons interact with the converter to generate an electron cloud
Implementation Method 2
An electrical field between the cathode and the anodes accelerates the electron cloud towards the anodes
Implementation Method 3
The outwardly extending plates 14 are designed to substantially align with incoming x-ray photons 90
Data Source
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AI summary
The present application relates to a combined anti-scatter grid, cathode, and carrier for a photon detector used in spectral CT imaging. The photon detector of the present application may include a cathode having at least one outwardly extending plate and at least one base plate, a substrate having at least one anode, and a converter material, such as for example, Cadmium Zinc Telluride ("CZT") or Cadmium Telluride. The at least one outwardly extending plate of the cathode may extend above the other detector components to act as an anti-scatter grid for the detector. Further, the at least one outwardly extending plate of the cathode may extend below the other detector components and be fixed to the at least one base plate of the detector. The converter material may be attached to at least one side of the at least one outwardly extending plate of the cathode.