Superconducting Cyclotron Spiral Pole Tips
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Solution Overview
Problem
Existing cyclotrons face challenges in achieving compact, cost-effective, and safe operation due to the need for separate mechanical support structures to mitigate decentering forces at high magnetic fields, and they often require complex variable-frequency acceleration systems.
Innovation Solution
A compact, cold, superconducting isochronous cyclotron design featuring superconducting coils and a magnetic yoke thermally coupled for efficient cooling, with spiral pole tips providing strong focusing and eliminating the need for separate mechanical support, allowing operation at high magnetic fields without external fringe field cancellation systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If separate mechanical support structures are used to mitigate decentering forces at high magnetic fields, then the cyclotron can operate at high magnetic fields, but the device complexity and cost increase
Solution Approach 1:
The magnetic yoke is thermally coupled to the cryogenic refrigerator cold finger, merging the magnetic field generation structure with the cooling system. This integration eliminates the need for separate mechanical support structures to mitigate decentering forces, as the yoke itself provides both magnetic function and thermal management, thereby reducing device complexity while maintaining high magnetic field operation
Solution Approach 2:
The magnetic yoke serves multiple functions simultaneously: it generates the magnetic field, provides thermal conduction to the cryogenic refrigerator, and structurally supports the superconducting coils. This multi-functionality allows the cyclotron to operate at high magnetic fields without requiring additional dedicated support structures, thus reducing overall system complexity
2Adaptability or versatility
If variable-frequency acceleration systems are used, then the cyclotron can adapt to different ion types and energies, but the device complexity increases
Solution Approach 1:
The patent employs an isochronous magnetic field design where the magnetic field strength varies with radius to compensate for relativistic mass increase of ions. This dynamic field configuration allows fixed-frequency acceleration to remain effective across different ion types and energies, achieving adaptability without requiring variable-frequency control systems
Solution Approach 2:
The magnetic field parameters are specifically designed to change with radial position, creating an isochronous field that maintains constant orbital period for ions of different masses and energies. This parameter variation in the magnetic field enables the use of fixed-frequency RF acceleration, thereby achieving versatility while minimizing control system complexity
3Power
If superconducting coils are cooled to cryogenic temperatures, then the magnetic field efficiency increases, but the thermal management complexity increases
Solution Approach 1:
The magnetic yoke is thermally integrated with the cryogenic refrigerator cold finger, merging the magnetic field generation structure with the cooling system. This integration simplifies thermal management by using the yoke itself as the thermal conduction path to cool the superconducting coils, eliminating the need for separate cooling infrastructure
Solution Approach 2:
The magnetic yoke acts as an intermediary thermal conduction medium between the cryogenic refrigerator and the superconducting coils. It efficiently transfers heat from the coils to the refrigerator while maintaining the structural integrity and magnetic field generation, thereby simplifying the overall thermal management system
4Reliability
If spiral pole tips with rare earth magnets are used, then the beam focusing and vertical stability improve, but the manufacturing complexity increases
Solution Approach 1:
The pole tips are segmented into discrete spiral-shaped elements that can be independently manufactured and assembled. This segmentation allows for standardized production of complex spiral geometries using modern manufacturing techniques, reducing overall manufacturing complexity while maintaining the sophisticated magnetic field configuration needed for beam stability
Solution Approach 2:
The pole tips utilize composite construction combining rare earth magnet materials with appropriate mounting structures. This composite approach enables the complex spiral geometry to be manufactured using standard techniques while incorporating high-performance magnetic materials, thereby achieving beam stability without excessive manufacturing complexity
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 reduces complexity and cost, enhances safety, and enables operation at high magnetic fields (e.g., 6 Tesla or above) with a fixed acceleration frequency, making it suitable for mobile and confined applications while maintaining beam stability and quality.
Implementation Method 1
The superconducting coils are cooled by the cryogenic refrigerator to a temperature (e.g., 10 to 12K) no greater than the superconducting transition temperature of the superconducting coils, and a voltage is supplied to the cooled superconducting coils to generate a superconducting current in the superconducting coils that produces a magnetic field
Implementation Method 2
a voltage is supplied to the cooled superconducting coils to generate a superconducting current in the superconducting coils that produces a magnetic field that accelerates the ion in the median acceleration plane
Implementation Method 3
The superconducting coils are cooled by the cryogenic refrigerator to a temperature (e.g., 10 to 12K) no greater than the superconducting transition temperature of the superconducting coils
Implementation Method 4
A cryogenic refrigerator is thermally coupled both with the superconducting coils and with the magnetic yoke
Implementation Method 5
spiral pole tips that supply a sector-based or azimuthally varying magnetic field to provide strong focusing to maintain the vertical stability of the accelerating ion
Data Source
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AI summary
A compact, cold, superconducting isochronous cyclotron can include at least two superconducting coils on opposite sides of a median acceleration plane. A magnetic yoke surrounds the coils and a portion of a beam chamber in which ions are accelerated. A cryogenic refrigerator is thermally coupled both with the superconducting coils and with the magnetic yoke. The superconducting isochronous cyclotron also includes sector pole tips that provide strong focusing; the sector pole tips can have a spiral configuration and can be formed of a rare earth magnet. The sector pole tips can also be separated from the rest of the yoke by a non-magnetic material. In other embodiments, the sector pole tips can include a superconducting material. The spiral pole tips can also include cut-outs on a back side of the sector pole tips remote from the median acceleration plane.