X-Ray Detector Rear-Side Electrodes for Dark Current Correction
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Solution Overview
Problem
Existing X-ray imaging systems face challenges in accurately accounting for local heating and material changes in semiconductor detectors during imaging, leading to errors in image quality due to sluggish temperature stabilization and inability to correct dark current measurements in real-time.
Innovation Solution
Incorporating additional electrodes on the rear side of the semiconductor detector to measure current flows outside imaging regions, allowing for real-time estimation of semiconductor state and enabling precise control of heating and image dataset correction using both first and second measurement values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional electrodes are added to measure current flows for real-time semiconductor state monitoring, then measurement precision and image quality improve, but device complexity increases
Solution Approach 1:
The additional electrodes serve multiple functions: they measure current flows for dark current correction, monitor local heating effects, and provide real-time semiconductor state information. This multi-functionality allows the system to achieve improved measurement precision without proportionally increasing device complexity, as the same structural additions serve multiple corrective purposes simultaneously.
Solution Approach 2:
The additional electrodes act as intermediary measurement elements that indirectly detect semiconductor state changes (temperature, material properties) through current flow measurements. Rather than directly measuring temperature or material changes, the electrodes provide electrical signals that serve as proxies for these physical states, enabling correction without direct sensing of the problematic parameters.
2Reliability
If real-time current flow measurement is implemented during imaging, then image quality and correction accuracy improve, but use of energy increases
Solution Approach 1:
The current flow measurement is performed continuously during the imaging process rather than as separate pre- and post-imaging steps. This continuous measurement approach ensures that dark current corrections remain accurate throughout the entire imaging sequence, maintaining high reliability without requiring additional energy-intensive measurement cycles outside the normal imaging workflow.
Solution Approach 2:
The system uses its own operational currents (bias currents flowing during imaging) to generate the measurement signals needed for correction. The same electrical currents that operate the detector also provide the measurement data for dark current correction, eliminating the need for separate measurement systems and reducing additional energy consumption.
3Device complexity
If sluggish temperature stabilization is used for semiconductor detector tempering, then device complexity remains low, but measurement precision deteriorates due to inability to account for local heating
Solution Approach 1:
The system implements a feedback mechanism where current flow measurements from the additional electrodes provide real-time information about semiconductor state changes. This feedback allows the system to dynamically adjust and correct for dark current variations caused by local heating, maintaining high measurement precision without requiring complex active temperature stabilization systems. The feedback loop operates at the signal processing level rather than requiring complex thermal control hardware.
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
Enhances image quality by accurately predicting and correcting for local heating and material changes, allowing for improved separation of X-ray photons and dynamic adjustment of imaging parameters, thus reducing errors and enabling more precise imaging.
Implementation Method 1
If an electron-hole pair is created in the semiconductor material by an X-ray photon, then by reason of the bias voltage, a charge cascade is triggered and the current spike resulting therefrom can be acquired
Implementation Method 2
A current sensor contacts the at least one additional electrode in order to acquire the current flow through the at least one additional electrode by way of second measurement values
Data Source
AI summary
An X-ray imager having an X-ray source, a semiconductor detector, and a processor. On a rear side of the semiconductor detector facing away from the front side, in each of a plurality of imaging regions of the semiconductor detector, at least one imaging electrode is arranged and a plurality of detectors each contact at least one of the imaging electrodes in order to acquire first measurement values relating to X-ray signals of the imaging electrodes. The processor is configured to establish an image dataset dependent upon the first measurement values. At least one additional electrode is arranged on the rear side of the semiconductor detector outside the imaging regions. At least one current sensor contacts the additional electrode or at least one of the additional electrodes in each case to acquire the current flow by way of the second measurement values relating to the at least one additional electrode.