X-Ray Tube Window Structure for Beam Purity and Hermetic Sealing
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Solution Overview
Problem
Existing x-ray tubes suffer from x-ray beam contamination due to undesired energy peaks generated by materials other than the target, and weak adhesion and hermetic seal failures of the x-ray window, leading to potential tube failure.
Innovation Solution
The x-ray window is constructed with a target mounted on an adhesion-layer, a conductive-layer, and a sealing-layer, where the sealing-layer is substantially different from the target and adhesion-layer materials to minimize interdiffusion, and a gap is maintained between the target and sealing-layer to prevent contamination, ensuring strong adhesion and a robust hermetic seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the target is directly mounted on the x-ray window without a gap, then the adhesion is stronger, but the x-ray beam becomes contaminated by interdiffusion of materials
Solution Approach 1:
The patent segments the interface between the target and x-ray window into distinct functional layers: an adhesion layer for strong bonding, a barrier layer to prevent interdiffusion, and a controlled gap to eliminate contamination pathways. This segmentation allows each layer to perform its specific function without interfering with others, resolving the contradiction between adhesion strength and beam purity.
Solution Approach 2:
The patent introduces intermediary layers (adhesion layer and barrier layer) between the target and x-ray window. These intermediaries serve as mediators that enable strong adhesion while preventing direct contact and interdiffusion between the target and window materials, thus eliminating x-ray beam contamination while maintaining structural integrity.
2Reliability
If the sealing-layer is made of the same material as the target, then the hermetic seal is stronger, but the x-ray beam becomes contaminated by material interdiffusion
Solution Approach 1:
The patent introduces a barrier layer as an intermediary between the sealing-layer and target. This barrier layer prevents direct contact and interdiffusion between the sealing-layer and target materials, eliminating x-ray beam contamination while allowing the sealing-layer to maintain strong hermetic sealing through its bonding interface with the target via the barrier layer.
Solution Approach 2:
The patent creates a composite structure at the sealing interface, combining the sealing-layer, barrier layer, and adhesion layer into a multi-material assembly. This composite structure leverages the complementary properties of different materials: the sealing-layer provides hermetic sealing, the barrier layer prevents interdiffusion, and the adhesion layer ensures strong bonding, thereby resolving the contradiction between seal strength and beam purity.
3Reliability
If multiple layers are added to the x-ray window construction, then adhesion and seal reliability improve, but the device complexity increases
Solution Approach 1:
The patent designs each layer to perform multiple functions simultaneously. For example, the adhesion layer provides both mechanical bonding and serves as a substrate for subsequent layers, while the barrier layer prevents interdiffusion and acts as a diffusion barrier. This multi-functionality reduces the need for additional specialized layers, thereby limiting complexity growth while maintaining high reliability.
Solution Approach 2:
The patent applies different material properties and thicknesses at different locations and interfaces. The adhesion layer has optimized thickness for bonding strength, the barrier layer has specific thickness for diffusion prevention, and the gap is precisely controlled for contamination prevention. This localized optimization ensures each layer performs its function efficiently without requiring excessive thickness or complexity throughout the entire structure.
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 construction provides a purer x-ray beam by avoiding contamination, enhances target adhesion, and ensures a reliable hermetic seal, thereby improving the operational stability of the x-ray tube.
Implementation Method 1
a target (17) mounted on an adhesion-layer (16)
Implementation Method 2
a conductive-layer (18) on the adhesion-layer (16) in the gap (21), the conductive-layer electrically connecting the target to the flange
Implementation Method 3
The target can generate x-rays in response to impinging electrons from the cathode
Data Source
AI summary
X-rays can be used for material identification. X-ray beam purity, target adhesion the x-ray window, and a robust hermetic seal of the x-ray window are useful. To achieve these objectives, a target 17 can be mounted by an adhesion-layer 16 on the x-ray window. The adhesion-layer 16 can include chromium. A sealing-layer 13 can seal the x-ray window to a flange 19. Material of the sealing-layer 13 can be different from material of the adhesion-layer 16. There can be a gap 21 between the flange 19 and the target 17. There can be a conductive-layer 18 on the x-ray window 14 in the gap 21. A thickness Ts of the adhesion-layer 16 between the sealing-layer 13 and the x-ray window 14 can be different than a thickness Tt of the adhesion-layer 16 between the target 17 and the x-ray window 14.