X-Ray Source Beam Deflection for Secondary Emission Compensation
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Solution Overview
Problem
Secondary radiation in X-ray sources, such as scattering and unwanted electron beam interactions, adversely affects image quality and can cause artifacts in X-ray imaging, particularly in CT scans, as existing compensation methods fail when a sample is present.
Innovation Solution
Record two images, one with the electron beam directed to the target and one to minimize secondary radiation, and generate a difference image to eliminate the secondary radiation's influence, using beam deflection and target positioning to isolate and subtract secondary radiation components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the anode is operated beyond its maximum rated current, then productivity and output are improved, but the anode overheats and suffers thermal damage
Solution Approach 1:
A cooling fluid is introduced as an intermediary substance between the anode and its thermal environment. The fluid flows through channels in the anode, absorbing excess heat and preventing overheating while allowing the anode to operate at higher currents for improved productivity
2Productivity
If the electron beam current is increased to improve productivity, then x-ray output is improved, but secondary emission from the cathode increases causing space charge effects that reduce efficiency
Solution Approach 1:
A feedback mechanism is implemented where a portion of the x-ray output is detected and used to automatically adjust the electron beam current. When secondary emission becomes significant, the system reduces the beam current to maintain optimal efficiency, creating a self-regulating system that prevents energy loss while maintaining high productivity
3Adaptability or versatility
If the x-ray source is miniaturized to improve adaptability, then device size is reduced, but heat dissipation becomes more difficult leading to overheating
Solution Approach 1:
The cooling approach transitions from two-dimensional surface cooling to three-dimensional internal cooling by incorporating cooling channels within the anode structure. This allows efficient heat dissipation in a miniaturized format by utilizing the internal volume of the anode for fluid flow, enabling compact design without sacrificing thermal management capability
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 method effectively reduces secondary radiation artifacts, enhancing image quality by isolating and subtracting secondary radiation contributions, resulting in sharper and more accurate X-ray images.
Implementation Method 1
When an electron beam is shot at a metal anode, some of the kinetic energy of the incident electrons is converted into x-rays
Implementation Method 2
The anode may be cooled by a cooling fluid that is passed through one or more cooling channels formed in the anode
Implementation Method 3
The anode may be cooled by a cooling fluid that is passed through one or more cooling channels formed in the anode
Implementation Method 4
In order to generate an electron beam, the cathode is heated to a temperature at which electrons are emitted from the cathode
Implementation Method 5
electrons that are emitted from the cathode as a result of kinetic energy transfer from the incident electrons... these electrons are referred to as secondary electrons
Data Source
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AI summary
An X-ray imaging system is disclosed, comprising an X-ray source; a sample position; a detector arranged to detect X-ray radiation downstream of said sample position; wherein said X-ray source comprises an electron source arranged to provide an electron beam; a target arranged to produce X-ray radiation upon impact by said electron beam, the target comprising a substrate and a target layer at least partly covering said substrate, wherein said target layer is arranged to produce X-ray radiation upon impact by said electron beam; means for directing the electron beam to a first position on said target layer and a second position selected from a position on said target at which the electron beam impacts directly upon the substrate and a position on an electron beam dump arranged so that substantially no X-ray radiation created by interaction between the electron beam and the electron beam dump reaches the detector; a controller arranged to record, using said detector, a first image with the electron beam directed to said first position, and a second image with the electron beam directed to said second position, and generate a difference image between the first image and the second image. A method for X-ray imaging is also disclosed.