Scanning Magnet Winding Layout for Compact Two-Axis Beam Deflection
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Solution Overview
Problem
Existing scanning magnets for particle therapy systems are either too large due to the need for multiple magnets to scan in two directions or suffer from errors in charged particle beam deflection angles due to inappropriate magnetic field distribution.
Innovation Solution
A scanning magnet design with multiple windings having forward and backward sections arranged at specific intervals, generating a magnetic field that deflects the charged particle beam in a controlled manner to reduce size and deflection errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two scanning magnets are arranged in cascade to scan the charged particle beam in two directions, then the scanning function is achieved, but the irradiation nozzle becomes large
Solution Approach 1:
The patent combines two separate scanning magnets into a single integrated scanning magnet that can scan the charged particle beam in two directions simultaneously. The magnet includes first and second windings arranged at specific intervals around the beam trajectory, allowing bidirectional scanning without requiring cascade arrangement of separate magnets, thereby reducing the irradiation nozzle size.
2Area of stationary object
If one scanning magnet is used to scan in two directions, then the nozzle size is reduced, but errors occur in the deflection angle due to inappropriate magnetic field distribution
Solution Approach 1:
The patent applies local quality by arranging windings with different configurations in different regions. The first and second windings are positioned at specific intervals (e.g., 120 degrees apart) around the beam trajectory, creating locally optimized magnetic field distributions that ensure accurate deflection angles at various irradiation positions while maintaining a compact nozzle design.
3Area of stationary object
If the scanning magnet size is reduced, then the system becomes more compact, but the magnetic field distribution becomes inappropriate causing deflection errors
Solution Approach 1:
The patent employs dynamic control through independent adjustment of currents in the first and second windings. By dynamically varying the current ratios and phases in different windings, the system maintains appropriate magnetic field distribution and accurate deflection angles even with a reduced magnet size, resolving the contradiction between compactness and reliability.
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 design reduces the size of the scanning magnet and minimizes errors in charged particle beam deflection angles, enhancing the precision and efficiency of particle therapy systems.
Implementation Method 1
the windings surrounding a columnar space through which the charged particle beam passes... generating a magnetic field that deflects the charged particle beam
Implementation Method 2
a magnetic field in a direction crossing the charged particle beam and deflecting the charged particle beam
Data Source
AI summary
A scanning magnet that deflects a charged particle beam has a winding U provided with grooves SL1 and SL4 provided at facing positions. A passing direction of a conductive wire forming the winding U passes through the groove SL1 in a γ-axis positive direction, and passes through the groove SL4 in a γ-axis negative direction. The winding U has a loop path SL1-SL4 in which the groove SL1 is directed to the γ-axis positive direction, and the groove SL4 is directed to the γ-axis negative direction. When a current flows in the γ-axis positive direction in a winding section U+ disposed in the groove SL1, a current flows in the γ-axis negative direction in a winding section U− disposed in the groove SL4. A yoke, the winding U, a winding V, and a winding W have a 120° rotationally symmetric structure with respect to a central axis of the yoke.