Planar Serpentine X-ray Tube Emitter for Long Throw Beam Stability
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Solution Overview
Problem
X-ray tubes with long throw lengths face challenges in maintaining a laminar electron beam, leading to unacceptable focal spot sizes, shapes, and positions, which affect image quality and the ability to produce useful X-ray images.
Innovation Solution
A stabilized electron emitter with a planar emitting surface, featuring a serpentine emitter pattern and elongate legs, is used to maintain beam laminarity and focus, combined with magnetic quadrupoles and dipoles for beam focusing and steering to optimize focal spot characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the throw length is lengthened, then back ion bombardment and evaporation of anode materials are decreased, but the electron beam becomes less laminar resulting in unacceptable focal spot characteristics
Solution Approach 1:
The electron emitter is divided into multiple discrete elements arranged in a specific pattern, allowing independent control of electron emission from each element. This segmentation enables the formation of a laminar electron beam even over long throw lengths by controlling the emission characteristics of individual elements.
Solution Approach 2:
Different regions of the electron emitter are designed with different emission characteristics. The emitter elements have varying dimensions and spacing to create localized variations in electron emission, which collectively form a laminar beam profile suitable for long throw distance applications.
2Object-affected harmful factors
If the throw length is lengthened, then anode material evaporation is reduced, but the ability to properly focus and position the electron beam is affected
Solution Approach 1:
The segmented emitter structure allows for precise control of electron emission from multiple discrete elements. By controlling the emission from each segment, the focal spot position and size can be accurately controlled even at long throw lengths where beam laminarity would normally deteriorate.
Solution Approach 2:
The emitter elements are designed with specific dimensional parameters and spacing that optimize electron emission characteristics for long throw distances. By carefully selecting emitter element dimensions, spacing, and arrangement, the focal spot characteristics can be maintained despite the increased throw length.
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 enhances spatial resolution and reduces image artifacts by ensuring a stable and focused electron beam, improving X-ray image quality.
Implementation Method 1
applying an electrical current to a cathode to cause electrons to be emitted from the cathode by thermionic emission
Implementation Method 2
combined with magnetic quadrupoles and dipoles for beam focusing and steering
Implementation Method 3
The electrons accelerate towards and then impinge upon an anode
Implementation Method 4
A second X-ray producing mechanism is referred to as Bremsstrahlung. In Bremsstrahlung, electrons emitted from the cathode decelerate when deflected by nuclei of the anode. The decelerating electrons lose kinetic energy and thereby produce X-rays.
Implementation Method 5
A first X-ray producing mechanism is referred to as X-ray fluorescence or characteristic X-ray generation. X-ray fluorescence occurs when an electron colliding with material of the anode has sufficient energy to knock an orbital electron of the anode out of an inner electron shell.
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A cathode head (15) can include: an insulating block (226) on a base (216); an electron emitter (222) with a planar emitter surface (234) formed by a plurality of elongate rungs (235) connected together through a plurality of turns (236) from a first emitter end (233 a) to a second emitter end (233b) so as to form a serpentine emitter pattern (230); a plurality of elongate legs (240) extending from the plurality of turns (236) at an angle relative to the planar emitter surface (234), each of the legs (240) being coupled with the insulating block (226); an elongate first lead leg (231a) at the first emitter end (233a) and an elongate second lead leg (231b) at the second emitter end (233b); a first electrical lead (227a) and a second electrical lead (227b) extending from the base (216); and a first electrical coupler (224a) coupling the first electrical lead (227a) to the first lead leg (231a) and a second electrical coupler (224b) coupling the second electrical lead (227b) to the second lead leg (23 lb).