PMT Delay Line Jumper Tuning for PET Timing Synchronization
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Solution Overview
Problem
Conventional PET imaging systems face challenges in achieving accurate timing resolution due to inherent timing variations in photomultiplier tube (PMT) transit times, leading to degraded timing resolution and increased complexity with active circuitry that degrades signal quality.
Innovation Solution
A variable delay device connected to PMTs in a time-of-flight gamma ray detection system, featuring a substrate with conductive pins and a jumper that introduces adjustable time delays, allowing for continuous or discrete adjustments to align PMT signals, thereby reducing transit time variations and enhancing timing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If active circuitry is used to compensate for PMT transit time variations, then timing resolution is improved, but device complexity increases and signal quality degrades
Solution Approach 1:
The patent extracts the delay adjustment function from complex active circuitry and implements it through simple passive delay lines with jumper selections. This removes the harmful complexity while preserving the timing correction capability, directly resolving the contradiction between timing resolution improvement and device complexity reduction.
Solution Approach 2:
The patent employs inexpensive passive delay lines and jumper configurations instead of expensive active circuitry. These simple passive components achieve the required timing compensation without degrading signal quality, resolving the contradiction between measurement precision and device complexity.
2Measurement precision
If active circuitry is used to adjust PMT signal delays, then timing synchronization is improved, but signal quality degrades
Solution Approach 1:
The patent uses passive delay lines and jumper configurations that do not actively process signals, thereby avoiding signal degradation. These simple passive components maintain signal integrity while achieving precise timing synchronization, resolving the contradiction between timing synchronization improvement and signal quality preservation.
3Measurement precision
If conventional delay adjustment methods are used, then timing variations are compensated, but manufacturing complexity and cost increase
Solution Approach 1:
The patent segments the delay adjustment into discrete selectable values using jumper configurations on delay lines. This segmentation allows for precise transit time compensation while maintaining manufacturing simplicity, as the discrete segments can be easily configured without complex assembly processes.
Solution Approach 2:
The patent employs inexpensive passive delay lines and standard jumper components that are easy to manufacture and assemble. This approach achieves accurate transit time compensation without increasing manufacturing complexity or cost, resolving the contradiction between measurement precision and ease of manufacture.
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
The variable delay device improves timing resolution by minimizing transit time variations across PMT channels, enhancing the accuracy of gamma ray detection and reducing signal degradation, thus improving the overall performance of PET imaging systems.
Implementation Method 1
The variation of this quantity from one PMT to another causes the signals to reach the analysis circuitry at different times. The variable delay device introduces adjustable time delays, allowing for continuous or discrete adjustments to synchronize PMT signals, thereby minimizing transit time variations.
Implementation Method 2
PET imaging relies on the conversion of gamma rays into light through fast and bright scintillation crystals, generating the scintillation events referred to above.
Data Source
AI summary
A variable delay device is connected to a photosensor of a time-of-flight gamma ray detection system and includes a substrate on which a plurality of conductive pins are affixed. A first terminal connected to a first of the plurality of pins and a second terminal connected to the second of the plurality of pins are also affixed to the substrate. A jumper electrically connects the plurality of pins at a predetermined distance relative to the substrate, and a time delay of the variable delay device is determined based on the electrical path between the first and second terminals formed by the plurality of pins and the jumper.