Gamma-Ray Detector Pulse Pile-Up Resolution via Mathematical Transform

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Solution Overview

Problem

Existing methods for gamma-ray spectroscopy face challenges in accurately characterizing individual signals due to pulse pile-up, where multiple gamma-rays arriving simultaneously produce combined signals that are difficult to differentiate from single events, leading to errors in spectroscopic analysis, especially at high radiation fluxes.

Innovation Solution

A method and apparatus that transform detector output data using mathematical transforms like Fourier transforms, model the signal forms, and evaluate functions to determine accurate parameters of individual signals, allowing for the recovery of usable data from pile-up affected signals by subtracting those that do not conform to accepted signal forms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple gamma-rays arrive simultaneously at the detector, then the detection rate increases, but pulse pile-up occurs causing signals to sum together and be counted as a single signal

Engineering Contradiction:
Improvedetection rateVSAvoidsignal characterization accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the combined pulse signal into individual component pulses by detecting discontinuities in the signal waveform. The processor identifies points where the derivative of the signal exceeds a threshold, effectively dividing the piled-up signal into separate gamma-ray events that can be individually analyzed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary signal processing by continuously monitoring the detector output for pulse discontinuities before final spectroscopic analysis. This preliminary detection and segmentation of piled-up pulses enables accurate characterization even at high detection rates.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the time between gamma-ray arrivals decreases, then the detection efficiency improves, but characterization of resultant signals becomes difficult

Engineering Contradiction:
Improvespectroscopic analysis speedVSAvoidsignal differentiation difficulty
Core Design Contradiction:
ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The system performs preliminary analysis of the combined signal waveform to identify discontinuities and segment pulses before final spectroscopic measurement. This preliminary segmentation simplifies subsequent characterization by reducing complex piled-up signals into identifiable individual pulse components.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces traditional electronic pulse processing with a mathematical approach using derivatives and threshold detection to identify pulse boundaries. This substitution enables accurate pulse separation even when pulses overlap significantly in time.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If the detector response time is increased to resolve individual signals, then signal characterization improves, but the time needed for spectroscopic analysis increases

Engineering Contradiction:
Improvesignal parameter accuracyVSAvoidanalysis time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary detection and segmentation of pulses within the combined signal waveform, identifying individual pulse boundaries through derivative analysis. This preliminary processing enables accurate parameter extraction without requiring extended measurement times.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system applies derivative detection with threshold criteria to identify pulse discontinuities, using a targeted approach that focuses computational effort on detecting signal boundaries rather than processing the entire waveform in detail, thus reducing analysis time while maintaining accuracy.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2359261B1Method and apparatus for resolving piled-up pulses by using a mathematical transform
Publication Date: 2018.04.25 SOUTHERN INNOVATION INT
  • EP2359261B1 patent drawingFigure 1
  • EP2359261B1 patent drawingFigure 2~3
  • EP2359261B1 patent drawingFigure 4~5

AI summary

A method and apparatus for resolving individual signals in detector output data, the method comprising obtaining or expressing the detector output data as a digital series, obtaining or determining a signal form of signals present in the data, forming a transformed signal form by transforming the signal form according to a mathematical transform, forming a transformed series by transforming the digital series according to the mathematical transform, the transformed series comprising transformed signals, evaluating a function of at least the transformed series and the transformed signal form and thereby providing a function output, determining at least one parameter of the function output based on a model of the function output, and determining a parameter of the signals from the at least one determined parameter of the function output. The method may include forming the model by modelling the function output.