Dielectric Cathode Interface for Compact X-Ray Source Miniaturization

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Solution Overview

Problem

Current X-ray tube technologies face limitations in miniaturization due to high voltage requirements, electrical insulation needs, and thermal management, leading to large dimensions and inefficiencies in X-ray generation.

Innovation Solution

The use of a dielectric/vacuum interface instead of a metal/vacuum interface for the cathode electrode, allowing for higher electrical fields without parasitic electron emissions, and the integration of a cold cathode with a dielectric mechanical part for reduced dimensions and improved thermal management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a metal/vacuum interface is used for the cathode electrode, then electrical isolation is maintained, but parasitic electron emissions occur due to high electric fields

Engineering Contradiction:
Improveelectrical isolationVSAvoidparasitic electron emissions
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a dielectric layer as an intermediary between the metal cathode electrode and the vacuum. This dielectric interface prevents direct contact between the metal and vacuum, eliminating the metal-vacuum interface that causes parasitic electron emissions through tunneling effects, while still allowing the electric field to function properly for electron emission control

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical and chemical parameters of the interface by replacing the metal-vacuum interface with a dielectric-vacuum interface. This parameter change modifies the electrical properties at the interface, preventing parasitic electron emissions while maintaining the necessary electrical isolation and field control capabilities

Inventive Principle:
Principle #35Parameter changes

2Volume of moving object

If the dimensions of X-ray tubes are reduced, then miniaturization is achieved, but electrical insulation and thermal management become insufficient

Engineering Contradiction:
Improvesource dimensionsVSAvoidelectrical insulation and thermal management
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent employs composite material structures combining metal electrodes with dielectric materials. The dielectric mechanical part integrated with the cathode electrode provides both electrical insulation and structural support in a compact configuration, enabling miniaturization while maintaining adequate electrical isolation

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent merges the dielectric insulation function with the mechanical structural support function into a single integrated dielectric mechanical part. This combination eliminates the need for separate insulation components, reducing overall device dimensions while maintaining electrical isolation and thermal management capabilities

Inventive Principle:
Principle #5Merging (Combining)

3Use of energy by moving object

If thermionic cathodes are used, then electron emission is achieved, but high operating temperatures cause expansion and evaporation problems

Engineering Contradiction:
Improveelectron emission capabilityVSAvoidcathode operating temperature
Core Design Contradiction:
Use of energy by moving objectVSTemperature

Solution Approach 1:

The patent replaces the thermionic emission mechanism (which relies on thermal energy) with a field emission mechanism based on the dielectric-vacuum interface. This substitution eliminates the need for high operating temperatures, avoiding thermal expansion and evaporation issues while maintaining effective electron emission control

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 approach enables the miniaturization of X-ray sources while maintaining high voltage capabilities and reducing noise emissions, leading to more compact and efficient ionizing radiation generation.

Implementation Method 1

The source (10) comprises a mechanical part (28) formed in a dielectric material having a dielectric rigidity greater than 30mV/m

Methodology Applied
Scientific EffectDielectric rigidity: Dielectric

Implementation Method 2

an electrode (24) disposed in vicinity of the cathode (14) and for generating an electron beam (18)

Methodology Applied
Scientific EffectElectrical field: Electric Field

Implementation Method 3

an anode (16) receiving the electron beam (18) and comprising a target (20) capable of generating ionizing radiation (22) as a function of the energy received from the electron beam (18)

Methodology Applied
Scientific EffectElectron beam bombardment: Electron Beam

Data Source

PatentEP3652773B1Compact, ionising ray-generating source, assembly comprising a plurality of sources and method for producing the source
Publication Date: 2021.05.26 THALES SA
  • EP3652773B1 patent drawingFigure 1
  • EP3652773B1 patent drawingFigure 2
  • EP3652773B1 patent drawingFigure 3

AI summary

The invention relates to a source generating ionising rays, and in particular X-rays, an assembly comprising a plurality of sources and a method for producing the source. The ionising ray-generating source comprises: · a vacuum chamber (12), · a cathode (14) capable of emitting an electron beam (18) in the vacuum chamber (12), · an anode (16) receiving the electron beam (18) and comprising a target (20) capable of generating an ionising radiation (22) from the energy received from the electron beam (18), and · an electrode (24) arranged in the vicinity of the cathode (14) and forming a Wehnelt electrode. According to the invention, the electrode (24) is composed of a conductive surface adhering to a concave face (26) of a dielectric material.