X-ray Photon Counting Detector Timing Circuits for Spectral Analysis
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Solution Overview
Problem
Conventional X-ray detectors fail to effectively utilize time intervals when energy bin thresholds are crossed, leading to incomplete information about X-ray photon detection events, which limits spectral estimation and detection of pile-up events, and results in inaccurate charge sharing corrections.
Innovation Solution
Incorporating timing circuits into X-ray detectors to capture temporal information about when each photon energy indication threshold is crossed, allowing for the correlation of photon energy with time indications, thereby enhancing spectral estimation, pile-up detection, and charge sharing corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional X-ray detectors only use voltage thresholds without timing circuits, then device complexity is reduced, but measurement precision of photon energy is insufficient
Solution Approach 1:
The patent transitions from one-dimensional voltage threshold detection to two-dimensional detection by incorporating time intervals as an additional dimension. Timing circuits measure when each threshold is crossed, creating temporal-spectral information that enhances photon energy measurement precision without requiring more voltage thresholds.
Solution Approach 2:
The patent introduces timing circuits as intermediary components between the voltage threshold detection and the final energy measurement. These circuits capture temporal information about threshold crossings and use it to improve energy estimation, acting as a mediator that extracts additional information from the existing voltage signal.
2Loss of information
If a small number of voltage thresholds are used, then device complexity is reduced, but loss of spectral information increases
Solution Approach 1:
Instead of increasing the number of voltage thresholds horizontally, the patent adds the time dimension vertically. By measuring when each threshold is crossed, the system recovers spectral information that would otherwise be lost, achieving detailed spectral estimation with fewer thresholds through temporal-spectral analysis.
3Measurement precision
If time intervals between threshold crossings are not measured, then device complexity is reduced, but detection accuracy of pile-up events deteriorates
Solution Approach 1:
Timing circuits serve as intermediary devices that capture temporal information between threshold crossings. This temporal data acts as a mediator to identify pile-up events by detecting abnormal time interval patterns, improving detection accuracy without requiring complex event-by-event analysis.
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 provides a more detailed estimate of the input spectrum, accurately detects pile-up events, and improves charge sharing corrections by utilizing temporal information, resulting in improved resolution and accuracy in X-ray photon energy measurement.
Implementation Method 1
the charge cloud resulting from an X-ray photon impinging on a sensor is converted to an amplified voltage by a charge sensitive amplifier (CSA)
Implementation Method 2
The voltage output of the CSA is compared against a number of user-settable thresholds
Data Source
AI summary
Various aspects include circuits and methods for use in X-ray detectors for obtaining time information regarding when an indication of an X-ray photon's energy, such as a CSA output voltage, and using the time information to obtain temporal-spectral data regarding an X-ray photon detection. The temporal-spectral data may be used to determine the X-ray photon's energy, to detect and account for multiple X-ray photon detection events (“pile ups”), and/or accommodating detection events in which charge is shared between two pixel detectors.