X-ray Tube Electron Collector Aperture for Diffraction Artifact Reduction

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Solution Overview

Problem

X-ray tubes suffer from kV-dependent artifacts due to primary beam interaction with the electron collector, resulting in image artifacts caused by Bragg diffraction, which worsen as the accelerating potential increases above the K-edge energy of the anode material.

Innovation Solution

The electron collector's aperture is shaped as a truncated cone with a wall angle greater than the Bragg angle to minimize diffraction, and an attenuating material is applied to absorb or attenuate diffracted x-rays, ensuring they do not combine with the primary beam passing through the window.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the electron collector is made with substantial mass and volume to sink heat, then thermal performance is improved, but x-ray diffraction artifacts worsen due to increased aperture wall depth

Engineering Contradiction:

Improvethermal performanceVSAvoidx-ray diffraction artifacts

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The aperture walls are designed with varying thickness - thinner at regions where x-rays pass through and thicker at regions for heat sinking. This local variation in mass distribution allows the structure to simultaneously minimize diffraction artifacts while maintaining thermal performance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The solution moves from a uniform 3D mass distribution to a strategically varied mass distribution, using dimensional optimization of wall thickness at different locations to resolve the contradiction between heat sinking and artifact reduction.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Use of energy by stationary object

If the aperture walls have substantial depth to house coolant lines, then thermal management is improved, but Bragg diffraction increases redirecting x-rays from their original vector

Engineering Contradiction:

Improvethermal managementVSAvoidBragg diffraction

Core Design Contradiction:

Use of energy by stationary objectVSObject-generated harmful factors

Solution Approach 1:

Coolant lines are positioned in regions of the electron collector where they provide thermal management without interfering with the x-ray beam path. The aperture wall thickness is optimized locally to accommodate coolant infrastructure only where necessary for heat removal.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The aperture wall structure acts as an intermediary, providing a pathway for coolant lines while maintaining x-ray transmission. The strategic placement of coolant infrastructure within the wall structure allows simultaneous achievement of thermal management and artifact reduction.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Use of energy by moving object

If the accelerating potential is increased above the K-edge energy, then x-ray intensity is improved, but characteristic radiation diffraction artifacts worsen dramatically

Engineering Contradiction:

Improvex-ray intensityVSAvoiddiffraction artifacts

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The aperture geometry parameters (wall thickness, diameter, shape) are optimized to minimize diffraction effects across the operating energy range. By carefully selecting these geometric parameters, the system maintains image quality even when operating above the K-edge energy for enhanced x-ray intensity.

Inventive Principle:

Principle #35Parameter changes

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 configuration reduces image artifacts by preventing diffracted x-rays from reaching the detector, maintaining image quality as the accelerating potential increases, while maintaining the thermal performance of the electron collector.

Implementation Method 1

interaction of the x-ray beam with the walls of the aperture can result in lattice diffraction (i.e., Bragg diffraction), and if the incident beam strikes a crystal at the Bragg angle relative to a diffracting plane, a portion of the incident beam will be redirected from its original vector

Methodology Applied

Scientific EffectBragg diffraction: Bragg Diffraction

Implementation Method 2

an attenuating material is applied to absorb or attenuate diffracted x-rays, ensuring they do not combine with the primary beam passing through the window

Methodology Applied

Scientific EffectAbsorption: Absorption (EM radiation)

Implementation Method 3

the coolant removes the heat load from the window and the surrounding region, thus maintaining the window and its attachment joints at low temperatures during operation of the x-ray tube

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS7796737B2Apparatus for reducing KV-dependent artifacts in an imaging system and method of making same

Publication Date: 2010.09.14 GE PRECISION HEALTHCARE LLC

AI summary

An x-ray tube includes a cathode positioned within a vacuum chamber and configured to emit electrons. The x-ray tube includes an anode positioned within the vacuum chamber to receive electrons emitted from the cathode and configured to generate a beam of x-rays from the electrons, a window positioned to pass the beam of x-rays therethrough, and an electron collector structure attached to the x-ray tube having an aperture formed therethrough to allow passage of x-rays therethrough. The aperture is shaped to prevent diffracted x-rays from combining with the beam of x-rays passing through the window.