Pulse Pile-Up Recovery via Multi-Voltage Threshold Sampling
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Solution Overview
Problem
High-energy particle detectors face performance degradation due to pulse pile-up events at high count rates, leading to count loss and deterioration of energy and position information, with existing methods struggling to perform real-time processing and accurate recovery of pulse information.
Innovation Solution
A method and system utilizing the Multi-voltage Threshold (MVT) technique for real-time processing of pulse pile-up events, involving the acquisition of digital waveform databases, generation of lookup tables, and multi-voltage threshold sampling to identify and process pile-up pulses efficiently, allowing for real-time recovery of pulse information at a low sampling rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the count rate of detector increases to meet high-activity and high-sensitivity demands, then the detection capability for nuclear medicine imaging is improved, but the pulse pile-up phenomenon becomes more serious causing count loss and deterioration of energy and position information
Solution Approach 1:
The patent pre-calculates and stores correction factors in lookup tables before actual measurement. When pile-up events occur, the system directly queries these pre-computed tables to obtain correction factors, avoiding real-time complex calculations and enabling rapid compensation for count loss and energy deterioration.
Solution Approach 2:
The patent introduces lookup tables as an intermediary between the detector and the data processing system. These tables store pre-computed correction factors that mediate the complex relationship between pile-up events and measurement accuracy, allowing the system to quickly compensate for pile-up effects without real-time complex computations.
2Measurement precision
If existing pile-up correction methods are used to address pulse pile-up, then some recovery of pulse information is achieved, but real-time processing capability is insufficient and accurate recovery of pile-up pulse information cannot be achieved
Solution Approach 1:
The patent pre-calculates correction factors for various pile-up scenarios and stores them in lookup tables before actual measurement. During real-time operation, the system simply queries these pre-computed tables based on observed pile-up characteristics, achieving both high accuracy and real-time processing speed without complex on-the-fly calculations.
Solution Approach 2:
The patent creates a simplified model of pile-up pulse waveforms and stores characteristic parameters in lookup tables. Instead of performing complex waveform analysis on actual pile-up events, the system copies relevant correction data from the pre-stored tables based on matching characteristics, achieving rapid and accurate recovery.
3Device complexity
If a low sampling rate is used to reduce data processing burden, then the data processing load is decreased, but the ability to accurately identify and process pile-up pulses is degraded
Solution Approach 1:
The patent introduces lookup tables as an intermediary that bridges the gap between low sampling rate and accurate pile-up identification. The tables store pre-computed correction factors and waveform characteristics that compensate for the limited information available at low sampling rates, enabling accurate pile-up detection and correction without requiring high sampling rates.
Solution Approach 2:
The patent changes the approach from time-domain detailed waveform analysis to parameter-based correction using lookup tables. By transforming the problem from analyzing continuous waveforms to querying discrete parameter tables, the system achieves accurate pile-up processing with minimal computational complexity and low sampling requirements.
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 MVT technique enables accurate and efficient real-time processing of pulse pile-up events, improving the recovery of pile-up pulse information and maintaining detector performance at high count rates, while facilitating simultaneous processing of multiple position-sensitive signals.
Implementation Method 1
gamma photons are converted into visible light photons using a scintillation crystal
Implementation Method 2
converted into scintillation pulse electrical signals using a photoelectric conversion device
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 2(c)
AI summary
A method for real-time processing of a pulse pile-up event comprises the following steps of: generating a fitted baseline value lookup table and a fitted energy value lookup table for a pulse falling edge, using a multi-voltage threshold sampling method to identify piled-up pulses and trigger a procedure of processing pulse signals; and using pulse priori information and acquired pulse information to acquire information of an incorrectly sampled portion due to a pulse pile-up by looking up in the tables, so as to recover information of the pile-up pulses in real time. First, in the disclosure the multi-voltage threshold sampling method is proposed to identify pile-up pulses at a high count rate and trigger a procedure of processing pulse signals. Next, pulse priori information and acquired pulse information are used to acquire information of an incorrectly sampled portion due to a pulse pile-up by looking up in the tables, to recover information of the piled-up pulses in real time. The method according to the disclosure is simple, highly efficient, can be realized easily in a real-time data acquisition system of a detector level, and is still capable of achieving a preferable effect of recovering formation of piled-up pulses at a low sampling rate.