SiPM Detector Signal Line Path Length Difference for Channel Reduction
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Solution Overview
Problem
The existing PET detectors with SiPMs require a large number of reading channels due to each SiPM being assigned a separate reading channel, leading to an enormous increase in the number of channels, which complicates the identification of scintillators and increases the complexity of the system.
Innovation Solution
The implementation of a detector module configuration where each SiPM has a signal line with two paths of different lengths, allowing for the identification of the SiPM that outputs an electric signal by measuring the time difference between signals passing through these paths, thereby reducing the number of reading channels needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If each SiPM is assigned a separate reading channel, then the detection capability is maintained, but the number of reading channels becomes enormous
Solution Approach 1:
Multiple SiPMs are merged into a single readout channel by sharing common signal lines. The patent groups multiple SiPMs together and uses a single reading channel for the entire group, significantly reducing the total number of channels while maintaining the ability to detect signals from individual SiPMs through time difference measurement.
Solution Approach 2:
The patent introduces signal lines with different lengths as an intermediary mechanism to distinguish between multiple SiPMs. By creating path length differences in the signal transmission lines, the system can identify which SiPM detected the signal without requiring separate reading channels for each SiPM.
2Ease of operation
If each SiPM has a separate reading channel, then the signal identification is straightforward, but the system architecture becomes complex
Solution Approach 1:
The patent replaces the traditional electrical connection-based identification system with a time-based measurement system. Instead of using separate reading channels for each SiPM, the system uses time difference of flight (TOF) measurement through signal lines of different lengths to identify which SiPM detected the signal, simplifying the electrical architecture.
Solution Approach 2:
The patent adds a temporal dimension to the signal identification process. By measuring the time difference between signals arriving at different locations through signal lines of different lengths, the system gains the ability to identify individual SiPMs without additional spatial separation or separate reading channels.
3Device complexity
If multiple SiPMs share a reading channel, then the number of reading channels is reduced, but the identification of individual SiPMs becomes difficult
Solution Approach 1:
The patent pre-configures signal lines with different lengths before signal detection occurs. This preliminary arrangement of signal paths with known different lengths allows the system to later identify which SiPM detected the signal by measuring the time difference, without requiring complex real-time analysis.
Solution Approach 2:
The patent uses the time difference of flight (TOF) measurement as an intermediary to resolve the identification problem. By measuring how long it takes for the signal to travel through the different length signal lines, the system can indirectly identify which SiPM detected the signal, solving the identification difficulty while maintaining reduced channel complexity.
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 enables precise identification of the scintillator and SiPM that converted the gamma ray signal, reducing the overall number of reading channels required and simplifying the system architecture.
Implementation Method 1
The scintillator converts a gamma ray emitted from internal tissue within a subject into light having a peak in the ultraviolet region and outputs the light
Implementation Method 2
The photomultiplier converts the light output from the scintillator into an electric signal
Implementation Method 3
Recently detectors using a SiPM as the photomultiplier have practically been utilized. In such a detector, a SiPM is installed for each scintillator
Implementation Method 4
The positron emission nuclide selectively captured into living tissue within the subject emits positrons, and the emitted positrons combine with electrons, undergo pair annihilation, and emit a pair of gamma rays in substantially opposite directions
Data Source
AI summary
A detector of an embodiment includes a plurality of photomultipliers, a signal line, and identifying circuitry. The photomultipliers each convert light converted from radiation into an electric signal and output the electric signal. The signal line has a first path and a second path through which the electric signal passes and that have different lengths for each of the photomultipliers. The identifying circuitry identifies the photomultiplier that outputs the electric signal by a time difference between the electric signal passing through the first path and the electric signal passing through the second path.