Diamond Micro-Sensitive Volumes for High-Resolution Dosimetry

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Solution Overview

Problem

Existing microdosimetry sensors, such as TEPCs and silicon-based microdosimeters, face limitations including large sensitive volumes, high-voltage requirements, gas supply needs, pulse pile-up issues, and limited spatial resolution, which hinder accurate microdosimetric measurements, especially for ion beams in hadron therapy.

Innovation Solution

A diamond-based sensor with isolated, single-standing micro-sensitive volumes surrounded by a non-electrically active material, which prevents charge generation and diffusion, thereby eliminating signal distortion and enhancing measurement accuracy with high spatial resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If TEPC detectors are used for microdosimetry measurements, then tissue equivalence is achieved, but the sensitive volumes are large (centimeter-sized) which reduces spatial resolution

Engineering Contradiction:
Improvetissue equivalenceVSAvoidspatial resolution
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The sensor divides the sensitive volume into multiple isolated micro-sensitive volumes (12) separated by non-electrically active material layers (13). This segmentation allows each micro-volume to independently detect radiation events with high spatial resolution while maintaining tissue equivalence through the diamond material composition.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sensor implements local quality by using diamond material specifically for the micro-sensitive volumes to ensure tissue equivalence, while using non-electrically active material (such as polymer or glass) for the separating layers to prevent charge diffusion. Each region has optimized properties for its specific function.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If silicon-based microdosimeters are used, then high spatial resolution is achieved, but tissue equivalence is limited due to silicon's atomic number (Z=14) requiring complex correction factors

Engineering Contradiction:
Improvespatial resolutionVSAvoidtissue equivalence
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The sensor implements local quality by using diamond material specifically for the micro-sensitive volumes to ensure tissue equivalence, while using non-electrically active material (such as polymer or glass) for the separating layers to prevent charge diffusion. Each region has optimized properties for its specific function.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If connecting bridges are used to readout signals from micro-sensitive volumes, then signal readout is enabled, but charge diffusion from surrounding material causes signal distortion

Engineering Contradiction:
Improvesignal readoutVSAvoidsignal accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The non-electrically active material layers (13) serve as intermediary barriers between the micro-sensitive volumes (12) and the surrounding environment. These layers prevent charge diffusion from surrounding materials into the sensitive volumes, thereby eliminating signal distortion while allowing electrodes to readout signals from each isolated micro-volume.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Measurement precision

If diamond-based sensor with isolated micro-sensitive volumes is used, then measurement accuracy and spatial resolution are improved, but device complexity increases due to multiple layers and isolation structures

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidstructure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sensor divides the sensitive volume into multiple isolated micro-sensitive volumes (12) separated by non-electrically active material layers (13). This segmentation allows each micro-volume to independently detect radiation events with high spatial resolution while maintaining tissue equivalence through the diamond material composition.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sensor implements local quality by using diamond material specifically for the micro-sensitive volumes to ensure tissue equivalence, while using non-electrically active material (such as polymer or glass) for the separating layers to prevent charge diffusion. Each region has optimized properties for its specific function.

Inventive Principle:
Principle #3Local quality

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 diamond-based sensor achieves improved accuracy and spatial resolution in microdosimetric measurements, reducing signal distortion and enabling precise dosimetry for ion beams, particularly in hadron therapy, while being more tissue-equivalent and radiation-hard compared to silicon-based sensors.

Implementation Method 1

microdosimetry, which rely on measurements of stochastic energy-deposition distributions in micro-sensitive volumes

Methodology Applied
Scientific EffectIonization: Ionisation

Implementation Method 2

a layer of a non-electrically active material extending around each micro-sensitive volume... which prevents charge generation and diffusion

Methodology Applied
Scientific EffectCharge diffusion prevention: Diffusion Barrier

Data Source

PatentEP3933448B1Diamond-based sensor comprising micro-sensitive volumes
Publication Date: 2025.04.23 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3933448B1 patent drawingFigure 1~2
  • EP3933448B1 patent drawingFigure 3~4F
  • EP3933448B1 patent drawingFigure 4G~5

AI summary

The invention relates to a so-called "fully 3D sensor", comprising - a plurality of diamond-based micro-sensitive volumes having opposite end faces, - a layer of non-electrically active material extending around each micro-sensitive volume of said plurality, - electrodes electrically connected to said end faces for signal readout.