X-ray Tube Beryllium Window Corrosion Protection

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Solution Overview

Problem

Beryllium windows in X-ray tubes corrode due to exposure to atmospheric gases, leading to vacuum state destruction, as conventional protective films allow acidic gases to penetrate and cause corrosion.

Innovation Solution

A stationary anode X-ray tube design featuring a beryllium window with an X-ray-resistive resin film, such as polyetheretherketone (PEEK) or polyimide, separated by a gap and adhered to a window frame, creating a dry gas-filled space that prevents corrosive acid formation and penetration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a beryllium window is used as the X-ray transmission window, then X-ray transmission accuracy is improved, but the window and brazed portion are corroded by atmospheric gases

Engineering Contradiction:
ImproveX-ray transmission accuracyVSAvoidvacuum state stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

A protective film is introduced as an intermediary layer between the beryllium window and the atmospheric environment. This film acts as a barrier that prevents corrosive gases from reaching the beryllium window and brazed portions, thereby maintaining vacuum state stability while preserving X-ray transmission accuracy through the thin beryllium window.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective film creates an inert barrier environment that isolates the beryllium window from reactive atmospheric gases. By preventing direct contact between atmospheric components and the beryllium surface, the film eliminates corrosion mechanisms while maintaining the structural integrity and transmission properties of the window.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

2Reliability

If a protective film is applied on the beryllium window, then corrosion resistance is improved, but the film deteriorates under X-ray irradiation

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidprotective film durability
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The invention changes the material parameters of the protective film by selecting specific polymers with high radiation resistance. The film is designed with controlled thickness and composition parameters that balance corrosion protection capabilities with resistance to X-ray induced deterioration, extending the operational lifespan of the protective layer.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If the beryllium window is made thinner, then X-ray transmission accuracy is improved, but corrosion susceptibility increases

Engineering Contradiction:
ImproveX-ray transmission accuracyVSAvoidcorrosion susceptibility
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The protective film serves as a mediator that decouples the relationship between window thickness and corrosion susceptibility. By providing an external barrier layer, the system allows the use of thinner beryllium windows for improved X-ray transmission without increasing corrosion risk, as the protective film assumes the corrosion resistance function.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design effectively prevents corrosion of the beryllium window and maintains the vacuum state by isolating it from corrosive gases, prolonging the X-ray tube's life cycle and ensuring high reliability.

Implementation Method 1

a dry gas is filled in the space

Methodology Applied
Scientific EffectPhysical barrier (dry gas layer):

Implementation Method 2

an X-ray transmission window formed of a beryllium thin plate, accommodated in the window frame, and configured to maintain, along with the window frame, a vacuum-tight state inside the envelope and transmit X-rays

Methodology Applied
Scientific EffectX-ray transmission: X-Ray

Data Source

PatentEP2881969B1X-ray tube and method of manufacturing the same
Publication Date: 2017.08.16 TOSHIBA ELECTRON TUBES & DEVICES CO LTD
  • EP2881969B1 patent drawingFigure 1
  • EP2881969B1 patent drawingFigure 2~3
  • EP2881969B1 patent drawingFigure 4~5

AI summary

According to one embodiment, an X-ray tube includes an envelope with an opening, an X-ray transmission assembly (20) mounted on the envelope and vacuum-tightly blocking the opening, a cathode and an anode target. The X-ray transmission assembly (20) includes a window frame (21), an X-ray transmission window (22), an X-ray-resistive resin film (23), a sealing member (25) and a dry gas (29). The X-ray transmission window (22) is formed of a beryllium thin plate, accommodated in the window frame (21), and configured to maintain, along with the window frame (21), a vacuum-tight state inside the envelope. The X-ray-resistive resin film (23) forms a space inside along with the window frame (21) and the X-ray transmission window (22). The dry gas (29) fills the space.