Coded Mask and Compton Imaging for Gamma Source Localization

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Solution Overview

Problem

Existing detection systems for gamma and X radiation are limited in their ability to accurately locate and image sources in two or three dimensions, especially at finite distances, and struggle with high noise levels and inefficient angular resolution over an extended spectral range.

Innovation Solution

A device combining coded mask imaging and Compton imaging techniques, using two plane detectors and a coded mask to enhance angular resolution and signal-to-noise ratio, allowing for precise two- or three-dimensional localization and energy measurement of radiation sources over a wide spectral range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If coded mask imaging is used, then angular resolution is improved, but field of view is limited

Engineering Contradiction:
Improveangular resolutionVSAvoidfield of view
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent combines coded mask imaging and Compton imaging techniques into a single detection system. The coded mask provides high angular resolution for sources within its field of view, while the Compton imaging detectors extend the field of view by detecting scattered photons from sources outside the coded mask's coverage area.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If Compton imaging is used, then field of view is improved, but angular resolution is limited

Engineering Contradiction:
Improvefield of viewVSAvoidangular resolution
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system merges Compton imaging detectors with a coded mask, where the Compton detectors provide wide field of view coverage and the coded mask enhances angular resolution for sources within its viewing area, creating a complementary relationship between the two techniques.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If gamma or X focusing is used, then angular resolution is improved, but focal length becomes excessively long

Engineering Contradiction:
Improveangular resolutionVSAvoidfocal length
Core Design Contradiction:
Measurement precisionVSLength of stationary object

Solution Approach 1:

The patent replaces the mechanical focusing system (gamma or X lenses with long focal lengths) with a combination of coded mask imaging and Compton imaging techniques. The coded mask uses geometric shadow patterns rather than optical focusing, eliminating the need for long focal lengths while achieving comparable or superior angular resolution.

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

4Device complexity

If existing detection systems are used, then device complexity is reduced, but localization precision at finite distances is insufficient

Engineering Contradiction:
Improvesystem simplicityVSAvoidlocalization precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent combines multiple detection techniques (coded mask imaging and Compton imaging) into an integrated system that maintains reasonable complexity while significantly improving localization precision at finite distances through the complementary strengths of each technique.

Inventive Principle:
Principle #5Merging (Combining)

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 combined technique provides improved angular resolution and signal-to-noise ratio, enabling precise localization and imaging of radiation sources in two or three dimensions, even at finite distances, and effectively measures energy and flux variations, overcoming limitations of existing systems.

Implementation Method 1

coded mask imaging consists in recording, on a position detector which is sensitive to gamma or X photons, the shadow of a mask which is partially opaque to these photons

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

a gamma or X photon, having a sufficiently high incident energy, has a high probability of yielding only part of this energy to an electron which is bound to the atoms of the first detector encountered, following an inelastic shock

Methodology Applied
Scientific EffectCompton scattering: Compton Scattering

Data Source

PatentEP2035861B1Device for locating and imaging gamma or x-radiation sources.
Publication Date: 2013.08.21 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2035861B1 patent drawingFigure 1
  • EP2035861B1 patent drawingFigure 2
  • EP2035861B1 patent drawingFigure 3~4

AI summary

Device for locating and imaging gamma or X-radiation sources, comprising: (a) a detection assembly (2) comprising at least two gamma or X-radiation detectors sensitive to position, as well as a coded mask (10) made of a radiation opaque material; and (b) electronic means (4) for processing the electrical pulses provided by said detectors, so as to locate the source and form a bi- or tri- dimensional image thereof. The device is characterized in that the electronic means (4) are suitable for reconstructing a bi- or tri- dimensional image of an X or gamma radiation source (16) by applying a data processing method which combines the principles of Compton imaging and coded-mask imaging.