Automated Beam Filter Positioning in Linear Accelerators
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Solution Overview
Problem
Conventional linear accelerators face challenges in efficiently automating the positioning of electron scattering foils and photon flattening filters, leading to time-consuming manual adjustments and potential contamination risks due to complex vacuum designs and radiation exposure issues with field light systems.
Innovation Solution
A modular beam filter positioning device with a carousel assembly that includes servo motor-controlled axes for precise movement of photon flattening filters, electron scattering foils, and a field light assembly, allowing for automated adjustments and easy maintenance, while minimizing radiation exposure and scattering losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual adjustment is used for positioning foils and filters, then precision can be achieved, but test time and adjustment time are very long
Solution Approach 1:
The patent replaces manual mechanical adjustment with an automated motorized positioning system. The exchanger includes motorized drives that automatically position the foil and filter assemblies, eliminating the need for time-consuming manual adjustments while maintaining positioning precision through controlled mechanical movement and feedback mechanisms.
Solution Approach 2:
The system performs self-positioning through automated control mechanisms. The exchanger automatically sequences the movement of foils and filters into their correct positions without requiring external manual intervention, enabling the system to service itself during operation and significantly reducing test and adjustment time.
2Productivity
If targets are located inside the vacuum envelope, then X-ray production is efficient, but vacuum contamination risk increases and design complexity increases
Solution Approach 1:
The patent extracts the target assembly from the vacuum envelope and positions it externally. This allows the target to remain close to the electron beam path for efficient X-ray production while being isolated from the vacuum environment, thereby eliminating the risk of vacuum contamination from water leaks in the cooling system and simplifying the vacuum envelope design.
Solution Approach 2:
The patent introduces a window or interface structure that mediates between the vacuum envelope and the external target assembly. This intermediary allows the electron beam to pass through and strike the external target while maintaining the integrity of the vacuum seal, thus enabling efficient X-ray production without compromising vacuum purity.
3Device complexity
If a thin film mirror is fixed in the beam centerline, then field light system is compact, but radiation scattering losses increase and beam contamination occurs
Solution Approach 1:
The patent replaces the fixed mirror with a movable mirror assembly that can dynamically adjust its position. The mirror is mounted on a movable support structure that allows it to be positioned out of the beam path when not needed, thereby eliminating continuous radiation scattering losses and beam contamination while maintaining system compactness through controlled movement rather than fixed placement.
4Weight of moving object
If thin film materials are used for the mirror, then the system is lightweight, but degradation due to radiation exposure occurs
Solution Approach 1:
The patent changes the material parameter of the mirror from thin film to a more robust material such as glass or metal. This parameter change increases the mirror's resistance to radiation degradation and improves reliability, while the movable design ensures the mirror remains lightweight enough for actuation and does not significantly increase the overall system weight.
Data Source
AI summary
A system includes a beam filter positioning device including a plate configured to support one or more beam filters, and one or more axes operable to move the plate relative to a beam line. A control mechanism is coupled to the one or more axes for controlling the movement of the axes and configured to automatically adjust the position of at least one of the one or more beam filters relative to the beam line.