Circular Accelerator Magnetic Gradient Layout for Beam Loss Suppression
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Solution Overview
Problem
The existing circular accelerator systems suffer from reduced beam extraction efficiency due to beam particles diverging in the vertical direction during extraction, leading to increased beam loss and decreased beam current, which prolongs treatment time in particle beam therapy.
Innovation Solution
A circular accelerator design with a magnetic field arrangement that includes a first region with a weak magnetic field gradient towards the outer periphery and a second region with a strong magnetic field gradient, positioned downstream of an orbit aggregation region, to maintain balance between convergence and divergence forces, thereby suppressing beam loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If beam particles are extracted from the accelerator, then beam extraction is achieved, but beam particles diverge in the vertical direction causing beam loss
Solution Approach 1:
The magnetic field gradient is made non-uniform in the vertical direction, with different gradient characteristics in different regions. Specifically, the gradient is stronger in the inner region and weaker in the outer region, creating local variations that balance convergence and divergence forces on beam particles during extraction, thereby reducing beam loss while maintaining extraction efficiency
Solution Approach 2:
The patent changes the magnetic field gradient parameter in the vertical direction by introducing a specific field configuration where the gradient varies with radial position. This parameter change creates a balance between the convergence force (from the main magnetic field) and divergence force (from the gradient), preventing beam particles from diverging excessively in the vertical direction during extraction
2Ease of operation
If beam particles diverge in the vertical direction, then extraction process is simplified, but beam current decreases
Solution Approach 1:
The magnetic field gradient is made non-uniform in the vertical direction, with different gradient characteristics in different regions. Specifically, the gradient is stronger in the inner region and weaker in the outer region, creating local variations that balance convergence and divergence forces on beam particles during extraction, thereby reducing beam loss while maintaining extraction efficiency
Solution Approach 2:
The patent changes the magnetic field gradient parameter in the vertical direction by introducing a specific field configuration where the gradient varies with radial position. This parameter change creates a balance between the convergence force (from the main magnetic field) and divergence force (from the gradient), preventing beam particles from diverging excessively in the vertical direction during extraction
3Loss of time
If beam loss increases, then extraction time is reduced, but treatment time increases
Solution Approach 1:
The magnetic field gradient is made non-uniform in the vertical direction, with different gradient characteristics in different regions. Specifically, the gradient is stronger in the inner region and weaker in the outer region, creating local variations that balance convergence and divergence forces on beam particles during extraction, thereby reducing beam loss while maintaining extraction efficiency
Solution Approach 2:
The patent changes the magnetic field gradient parameter in the vertical direction by introducing a specific field configuration where the gradient varies with radial position. This parameter change creates a balance between the convergence force (from the main magnetic field) and divergence force (from the gradient), preventing beam particles from diverging excessively in the vertical direction during extraction
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 design enhances beam extraction efficiency, allowing for higher beam current and shorter treatment times in particle beam therapy systems by maintaining the balance of forces on the beam particles.
Implementation Method 1
a first magnetic field region in which closed trajectories of the beams with different energies are eccentric and which has a magnetic field gradient in which a magnetic field becomes weak toward an outer peripheral side, and a second magnetic field region in which the magnetic field becomes strong toward the outer peripheral side
Data Source
AI summary
There is provide a circular accelerator and a particle beam therapy system that can improve the beam extraction efficiency. A circular accelerator that accelerates and extracts charged particle beams circulating in a magnetic field includes a first magnetic field region in which closed trajectories of the beams with different energies are eccentric and which has a magnetic field gradient decreasing in the magnetic field toward an outer peripheral side and a second magnetic field region having a magnetic field gradient increasing in the magnetic field toward the outer peripheral side. A border between the first magnetic field region and the second magnetic field region is located on a downstream side in a traveling direction of the beam with respect to a predetermined region in which an interval between the closed trajectories of the beams with the different energies is narrowest.