Multi-Grid X-Ray Source for Arc and Ion Bombardment Protection
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Solution Overview
Problem
X-ray tubes experience arcing and ion back bombardment, which can damage internal components like the cathode due to high-energy ion pulses, causing damage to nanotube emitters.
Innovation Solution
The implementation of multiple grids, specifically a first grid to control field emission and a second grid positioned between the first grid and the anode, intercepts arcs and ions, reducing the risk of damage to field emitters by providing a path for arcs and decelerating ions, thus protecting the emitters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single grid is used to control field emission, then the structure is simple, but the protection against arcing and ion bombardment is insufficient
Solution Approach 1:
The single grid is divided into multiple grids (first grid, second grid, and third grid) positioned at different locations between the cathode and anode. Each grid provides a specific function: the first grid controls field emission, the second grid intercepts arcs and ions, and the third grid provides additional protection. This segmentation allows the system to achieve better protection against arcing and ion bombardment while maintaining reasonable structural complexity.
Solution Approach 2:
The second and third grids act as intermediary elements between the cathode and anode, specifically positioned to intercept arcs and ions before they reach the cathode. These intermediary grids provide a protective barrier that absorbs or deflects harmful charged particles, thereby protecting the field emission structure from damage while allowing the electron beam to pass through to generate x-rays.
2Reliability
If multiple grids are added to protect against arcing and ion bombardment, then the protection effectiveness increases, but the device complexity increases
Solution Approach 1:
The protective function is segmented across multiple grids rather than concentrated in a single grid. This allows each grid to be optimized for its specific protective role while distributing the overall complexity across multiple simpler components. The segmentation enables incremental protection where each grid adds a layer of defense against arcing and ion bombardment.
Solution Approach 2:
The multiple grids serve multiple functions simultaneously: controlling field emission, intercepting arcs, deflecting ions, and maintaining vacuum integrity. By designing the grids to perform multiple functions, the patent reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving comprehensive protection.
3Reliability
If grids are positioned closer to the cathode to better protect field emitters, then the protection effectiveness increases, but the risk of grid damage from high-energy particles increases
Solution Approach 1:
The protective function is distributed across multiple grids positioned at different distances from the cathode. The second grid is positioned closer to the cathode to provide primary protection, while the third grid is positioned farther away to provide secondary protection and absorb some of the high-energy particle impact. This segmentation of the protective barrier allows closer positioning of at least one protective grid without concentrating all the impact resistance requirements on a single grid.
Solution Approach 2:
The third grid, positioned farther from the cathode, acts as a cushioning element that intercepts and absorbs some of the high-energy ions and arcs before they reach the second grid and cathode. This prior cushioning reduces the energy of incoming particles, thereby protecting the more vulnerable second grid and field emitters from direct high-energy bombardment while still maintaining effective protection.
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
The use of multiple grids effectively reduces the occurrence of arcing and ion bombardment damage, protecting field emitters and maintaining the operational integrity of x-ray sources by intercepting and decelerating high-energy particles.
Implementation Method 1
a field emitter configured to generate an electron beam
Implementation Method 2
a first grid configured to control field emission from the field emitter
Implementation Method 3
a second grid disposed between the first grid and the anode, intercepts arcs and ions
Implementation Method 4
decelerating ions, thus protecting the emitters
Data Source
AI summary
Some embodiments include an x-ray source, comprising: an anode; a field emitter configured to generate an electron beam; a first grid configured to control field emission from the field emitter; a second grid disposed between the first grid and the anode; and a middle electrode disposed between the first grid and the anode wherein the second grid is either disposed between the first grid and middle electrode or between the middle electrode and the anode.