Energy-Resolving Photon Detector Pixel with Offset Autocalibration
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Solution Overview
Problem
Energy-resolving photon counting detectors suffer from threshold voltage variations and gain fluctuations due to temperature changes and manufacturing tolerances, leading to inaccurate photon energy determination.
Innovation Solution
An energy-resolving photon counting detector pixel with an offset unit that performs autocalibration to determine correction signals for the detecting and comparing units, mitigating offset errors by adjusting threshold voltages and gains, allowing in-situ calibration before photon irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If transistors are used to implement detecting and comparing units, then the detector can process photon signals, but threshold voltage variations occur due to manufacturing tolerances and temperature changes
Solution Approach 1:
The patent applies preliminary action by performing calibration before the detector is used for photon measurement. An offset unit determines correction signals in advance by analyzing signal characteristics without photon input, allowing the threshold voltage variations to be compensated before actual measurement begins. This separates the calibration process from the measurement process, ensuring accurate energy determination despite transistor threshold variations.
2Manufacturing precision
If calibration is performed offline, then manufacturing tolerances can be addressed, but the detector cannot be calibrated in-situ and may require re-calibration under different temperature conditions
Solution Approach 1:
The patent implements dynamics by making the calibration process adaptive and continuous rather than static and one-time. The offset unit continuously monitors signal characteristics and adjusts correction signals in real-time based on current operating conditions including temperature. This allows the detector to maintain accurate calibration across varying temperature conditions without requiring offline intervention or manual re-calibration.
3Device complexity
If gain variation is present due to manufacturing tolerances, then the detector structure remains simple, but the transfer function changes between pixels and over time
Solution Approach 1:
The patent applies feedback by implementing an offset unit that continuously monitors the output signals from detecting and comparing units and adjusts correction signals accordingly. The feedback mechanism analyzes signal characteristics such as pulse height and timing, then generates appropriate correction signals to compensate for gain variations. This closed-loop approach maintains consistent energy resolution across different pixels and over time without adding complex external calibration equipment.
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
Improves the accuracy of photon energy determination by compensating for threshold voltage and gain variations, ensuring precise energy resolution without requiring offline calibration.
Implementation Method 1
a photoconductor (2) configured for outputting a first signal as a result of absorbing a photon
Data Source
AI summary
An energy-resolving photon counting detector pixel. The energy-resolving photon counting detector may include a plurality of such pixels. In an embodiment, the detector pixel is operable in a calibration mode, in which mode an offset unit determines a correction signal to be provided to the detecting unit and/or to the comparing unit for correcting an offset in the detecting unit and/or comparing unit.