Distributed Fiber Optic Radiation Detector

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Solution Overview

Problem

Existing radiation detection methods, such as gaseous ionization and semiconductor detectors, are costly, complex, and require multiple installations for adequate coverage, while existing optical fiber systems lack the necessary sensitivity and resolution for reliable ionizing radiation detection.

Innovation Solution

A distributed fiber optic radiation detector using optical fibers with elongate electrodes and a gas gap, where a potential difference is applied to create a cascade of charged particles in the presence of ionizing radiation, detected through distributed acoustic sensing techniques, which can differentiate between locations and provide reliable thermal and acoustic signatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multiple separate radiation detectors are installed at various locations to provide sufficient coverage, then radiation monitoring coverage is improved, but installation complexity and cost increase

Engineering Contradiction:
Improveradiation monitoring coverage areaVSAvoidinstallation complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent combines multiple detector functions into a single distributed fiber optic system. The optical fiber acts as both the sensing element and the communication medium, eliminating the need for separate power supplies, signal processing electronics, and communication systems at each monitoring location. This merging approach provides extensive coverage while reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The optical fiber serves multiple functions simultaneously: it acts as the radiation-sensitive medium, the signal transmission medium, and the communication link to the control center. This multi-functionality eliminates the need for separate components at each monitoring point, reducing installation complexity while maintaining comprehensive coverage.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Area of stationary object

If multiple separate radiation detectors are installed at various locations to provide sufficient coverage, then radiation monitoring coverage is improved, but cost increases

Engineering Contradiction:
Improveradiation monitoring coverage areaVSAvoidsystem cost
Core Design Contradiction:
Area of stationary objectVSQuantity of substance

Solution Approach 1:

The patent combines multiple detector functions into a single distributed fiber optic system. The optical fiber acts as both the sensing element and the communication medium, eliminating the need for separate power supplies, signal processing electronics, and communication systems at each monitoring location. This merging approach provides extensive coverage while reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The optical fiber serves multiple functions simultaneously: it acts as the radiation-sensitive medium, the signal transmission medium, and the communication link to the control center. This multi-functionality eliminates the need for separate components at each monitoring point, reducing installation complexity while maintaining comprehensive coverage.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If conventional optical fiber radiation detection is used, then remote detection capability is provided, but detection sensitivity and resolution are insufficient

Engineering Contradiction:
Improveremote detection capabilityVSAvoiddetection sensitivity
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent enhances the local interaction between radiation and the optical fiber by introducing a high-permittivity dielectric material in direct contact with the fiber surface. This creates a concentrated electric field region that amplifies the radiation effect locally, significantly improving detection sensitivity while maintaining the remote monitoring capability through the optical fiber.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the electrical parameters of the optical fiber environment by introducing a high-permittivity dielectric material. This material concentration effect modifies the electric field distribution and enhances the radiation-induced signal, thereby improving detection sensitivity and resolution without compromising remote detection capability.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If gaseous ionisation detectors with high potential difference are used to achieve avalanche multiplication, then detection sensitivity is improved, but power consumption and device complexity increase

Engineering Contradiction:
Improvedetection sensitivityVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by stationary object

Solution Approach 1:

The patent enhances the local interaction between radiation and the optical fiber by introducing a high-permittivity dielectric material in direct contact with the fiber surface. This creates a concentrated electric field region that amplifies the radiation effect locally, significantly improving detection sensitivity while maintaining the remote monitoring capability through the optical fiber.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent replaces the conventional gaseous ionisation detection mechanism with an optical field-based detection method. Instead of using high voltage to create avalanche multiplication in gas, the system uses radiation-induced changes in the optical fiber's electromagnetic properties, which are then detected optically. This substitution dramatically reduces power consumption while maintaining or improving detection sensitivity.

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

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

This solution allows for efficient, cost-effective, and remotely manageable detection of ionizing radiation across multiple locations with high spatial resolution, reducing installation complexity and power demands, while providing accurate localization and discrimination of radiation events.

Implementation Method 1

In the presence of ionising radiation some atoms/molecules of the gas will be ionised and the resulting electrons and ions will allow a current to flow between the electrodes

Methodology Applied
Scientific EffectIonisation: Ionisation

Implementation Method 2

The strength of the applied potential difference may be relatively high so as to lead to avalanche multiplication in the gas leading to a relatively large current pulse for each detection event

Methodology Applied
Scientific EffectAvalanche multiplication: Avalanche Breakdown

Implementation Method 3

The cascade will not only result in a flow of charged particles but will also generally produce a pressure wave in the gaseous medium, i.e. an acoustic wave

Methodology Applied
Scientific EffectAcoustic wave generation: Acoustic Emission

Implementation Method 4

This will lead to an optical path length change resulting from modulation of the refractive index of the optical fibre and possibly any thermal expansion of the fibre material

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2850456B1Radiation detector
Publication Date: 2019.04.17 OPTASENSE HOLDINGS LIMITED
  • EP2850456B1 patent drawingFigure 1~3
  • EP2850456B1 patent drawingFigure 4~6
  • EP2850456B1 patent drawingFigure 7~8

AI summary

This application describes a radiation detector apparatus comprising: at least one optical fibre (104) suitable for distributed fibre optic acoustic/vibration sensing adjacent at least a first electrode (201) spaced apart from a second electrode (202) with a gas between the first and second electrodes.