Structured Organic Scintillator with Triphenylbismuth

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Solution Overview

Problem

Existing organic scintillators face challenges in achieving high sensitivity and spatial resolution without compromising manufacturing complexity, particularly in incorporating high Z materials like lead or bismuth into capillaries, which tend to precipitate and clog, limiting their use in imaging ionizing radiation.

Innovation Solution

A structured organic scintillator is developed using glass capillaries filled with a polymer material comprising vinyltoluene, styrene, or vinylxylene, with triphenylbismuth as a crosslinking agent, allowing for homogeneous bismuth distribution and high Z effect without precipitation, optimized for imaging with ionizing radiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high Z materials like lead or bismuth are incorporated into organic scintillator material, then the probability of interaction with ionizing radiation increases (improving sensitivity), but the materials tend to precipitate and clog, making manufacturing difficult

Engineering Contradiction:
ImprovesensitivityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses specific organic compounds (carriers) as intermediaries to dissolve and transport high Z materials (bismuth, lead) within the scintillator matrix. These carrier molecules prevent precipitation by maintaining solubility, enabling homogeneous distribution without clogging during manufacturing processes.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies chemical parameters by selecting specific carriers and controlling their concentration ratios relative to the high Z materials. This parameter optimization ensures complete dissolution and prevents precipitation, resolving the manufacturing difficulty while maintaining high sensitivity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the thickness of the scintillator is increased to maximize interaction probability, then sensitivity improves, but spatial resolution degrades due to light diffusion

Engineering Contradiction:
ImprovesensitivityVSAvoidspatial resolution
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent divides the scintillator into a segmented structure with multiple capillaries (internal diameter 1-100 micrometers) filled with scintillator material. This segmentation confines light propagation within each capillary, preventing lateral diffusion while allowing increased effective thickness for radiation interaction, thus maintaining both sensitivity and spatial resolution.

Inventive Principle:
Principle #1Segmentation

3Reliability

If inorganic scintillators are used to achieve high density and moderate thickness, then interaction probability improves, but response time becomes too long for rapid imaging applications

Engineering Contradiction:
Improveinteraction probabilityVSAvoidresponse time
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent creates a composite material by incorporating high Z elements (bismuth, lead) into an organic scintillator matrix. This composite combines the high density and interaction probability of inorganic scintillators with the fast response time (typically <10 ns) of organic scintillators, achieving both high sensitivity and rapid response for dynamic imaging.

Inventive Principle:
Principle #40Composite materials

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 solution enables the creation of a scintillator with improved sensitivity and spatial resolution, maintaining transparency and low scintillation decay time, suitable for imaging with X or Gamma radiation, while avoiding complex manufacturing steps.

Implementation Method 1

the role of the scintillator is to convert ionizing radiation into visible light radiation

Methodology Applied
Scientific EffectScintillation: Scintillation

Implementation Method 2

these capillaries being filled with a polymer material... emit as much as possible in the visible range... to limit the diffusion of visible light because luminescence is an isotropic phenomenon

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3237929B1Bismuth-charged structured solid organic scintillator
Publication Date: 2019.02.13 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3237929B1 patent drawingFigure 1~3b
  • EP3237929B1 patent drawingFigure 2c~3e
  • EP3237929B1 patent drawing

AI summary

The invention relates to a scintillator for imaging using X-rays or gamma rays or charged particles, including a network of glass capillaries (1) with an inner diameter no greater than 500 micrometres, said capillaries being filled with a polymer material (2) made up of at least: (i) a monomer selected from the group comprising vinyltoluene, styrene and vinylxylene and the isomers thereof; (ii) a cross-linking agent made up of a divinylbenzene or a dimethacrylate having a central chain which includes 1 to 12 carbon atoms; and (iii) triphenylbismuth, the cross-linking agent being provided to make up 10 wt % to 60 % wt of the mixture thereof with the monomer, and the triphenylbismuth being provided to make up at least 5 wt %, the cross-linking agent being provided in a ratio of 0.75 to 2.25 times the weight content of the triphenylbismuth.