Energy-Resolving Photon Counting Pixel for CSA Headroom Control
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Solution Overview
Problem
Energy-resolving photon counting detectors face issues with insufficient headroom in the CSA output signal due to CSA base level shifts caused by dark current and charge sharing, leading to incorrect photon energy determination.
Innovation Solution
The detector pixel includes a CSA base level shift detector to monitor and reset the CSA based on detected shifts, ensuring sufficient headroom and accurate photon energy determination by correcting counter values using the number of resets performed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the CSA operates without base level monitoring, then the device complexity is reduced, but the measurement precision of photon energy determination deteriorates due to insufficient headroom
Solution Approach 1:
The patent applies preliminary action by monitoring the CSA base level continuously and performing reset operations before the base level shift causes insufficient headroom. The base level detector proactively detects shifts and triggers reset signals to maintain the CSA output signal within the valid dynamic range, preventing measurement errors before they occur.
Solution Approach 2:
The patent implements feedback by using the base level detector to continuously monitor the CSA base level and generate reset signals when shifts are detected. This closed-loop feedback mechanism ensures the CSA operating point remains stable and within the required range, maintaining measurement precision without requiring excessive headroom in the original design.
2Measurement precision
If the CSA headroom is increased to accommodate base level shifts, then the measurement precision is maintained, but the device complexity and signal processing requirements increase
Solution Approach 1:
The patent extracts the base level monitoring and reset control functions into a separate base level detector circuit, independent from the main CSA signal processing path. This allows the CSA to operate with minimal headroom while the extracted monitoring function handles base level stabilization, separating the stabilization requirement from the measurement path complexity.
3Measurement precision
If reset operations are performed frequently to correct base level shifts, then the measurement precision is maintained, but the productivity of photon counting decreases due to lost counting opportunities
Solution Approach 1:
The patent applies self-service by designing the base level detector to automatically monitor and trigger reset operations without external intervention. The system self-regulates the CSA base level, minimizing disruptions to photon counting by performing resets only when necessary, thus maintaining both precision and productivity autonomously.
Solution Approach 2:
The patent changes the operational parameter of the CSA by dynamically adjusting the base level through controlled reset operations. By modifying the base level parameter in response to detected shifts, the system maintains optimal operating conditions without requiring continuous high-frequency resets, balancing precision and counting 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
This approach ensures reliable photon energy determination by maintaining headroom and correcting for CSA base level shifts, improving the accuracy of photon counting and imaging processes.
Implementation Method 1
Photoconductor 2 outputs a photocurrent as a result of absorbing a photon
Data Source
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AI summary
Aspects of the present disclosure relate to an energy-resolving photon counting detector pixel. Further aspects of the present disclosure relate to an energy-resolving photon counting detector comprising a plurality of such pixels, and to an energy-resolving photon counting system comprising the same. In accordance with an aspect of the present disclosure, a CSA base level shift detector is used for determining a shift in the CSA base level over time relative to a first level. The pixel is configured to reset the CSA in dependence of the determined CSA base level shift.