Compact Superconducting Cyclotron Cold Magnet Integration

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Solution Overview

Problem

Conventional cyclotrons face challenges in achieving high magnetic fields while maintaining compactness and safety, particularly due to the need for complex support structures and variable-frequency acceleration systems, which limits their portability and efficiency.

Innovation Solution

A compact, cold, weak-focusing, superconducting cyclotron design featuring a magnetic yoke in thermal contact with cryogenic coils, eliminating the need for separate support structures and allowing operation at high fields without a complex frequency system, with all magnet components contained within a cryostat for enhanced safety and reduced size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional cyclotrons use resistive magnet technology or superconducting coils with separate support structures, then high magnetic fields (1-5 Tesla) can be achieved, but the device complexity and size increase due to required mechanical support systems

Engineering Contradiction:
Improvemagnetic field strengthVSAvoidsupport structure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent merges the magnetic yoke and superconducting coils into a single integrated cold magnet assembly. The coils are directly mounted on the cold yoke structure, eliminating the need for separate mechanical support structures that would be required for conventional resistive magnets or superconducting systems. This integration reduces device complexity while maintaining high magnetic field capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cold magnetic yoke serves multiple functions simultaneously: it provides the magnetic circuit path, structural support for the superconducting coils, and thermal conduction path to the cryogenic refrigerator. This multi-functionality eliminates the need for separate support structures and reduces overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If conventional cyclotrons use isochronous design with increasing magnetic field, then relativistic compensation is achieved, but the acceleration frequency must be fixed and the magnetic field profile becomes complex requiring precise control

Engineering Contradiction:
Improvephase stabilityVSAvoidfrequency control system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of using the conventional isochronous approach where magnetic field increases with radius to compensate for relativity, this patent inverts the approach by using weak focusing with decreasing magnetic field. The fixed frequency acceleration is maintained through weak focusing effects rather than isochronous field shaping, simplifying the frequency control system.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the magnetic field profile parameter from increasing (isochronous) to decreasing (weak focusing) with radius. This parameter change allows fixed frequency operation without complex field shaping, reducing the complexity of the frequency control system while maintaining reliable acceleration.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If superconducting coils are cooled to cryogenic temperatures, then high magnetic fields can be sustained, but thermal management complexity increases requiring separate cooling systems

Engineering Contradiction:
Improvecoil temperatureVSAvoidthermal management system
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The magnetic yoke and cooling system are merged into a single integrated structure. The yoke serves as both the magnetic circuit and the thermal conduction path to the cryogenic refrigerator, eliminating the need for separate cooling infrastructure and reducing thermal management complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cold magnetic yoke performs multiple functions: providing the magnetic circuit path, supporting the superconducting coils, and conducting heat away from the coils to the cryogenic refrigerator. This multi-functionality simplifies thermal management by eliminating separate cooling systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Volume of moving object

If compact cyclotron design is pursued, then portability and safety are improved, but achieving high magnetic fields becomes more difficult due to space constraints

Engineering Contradiction:
Improvecyclotron sizeVSAvoidmagnetic field strength
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The integration of coils directly onto the cold yoke structure eliminates the need for additional support infrastructure, allowing the entire magnet assembly to be compact. This merging enables high magnetic fields to be achieved in a smaller volume, improving portability and safety.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The use of superconducting coils operating at cryogenic temperatures enables higher magnetic field densities compared to conventional resistive magnets. This parameter change in operating temperature allows achieving high magnetic fields in a more compact configuration.

Inventive Principle:
Principle #35Parameter changes

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 achieves a significant reduction in size, improved safety, and cost-effectiveness, enabling the cyclotron to operate at high magnetic fields (up to 8 Tesla) with fixed frequency, making it suitable for portable and diverse applications, including remote use.

Implementation Method 1

at least two superconducting coils on opposite sides of a median acceleration plane... A voltage is supplied to the cooled superconducting coils to generate a superconducting current in the superconducting coils that produces a magnetic field in the median acceleration plane

Methodology Applied
Scientific EffectSuperconductivity: Superconductivity

Implementation Method 2

The superconducting coils and the magnetic yoke are cooled by the cryogenic refrigerator to a temperature no greater than the superconducting transition temperature of the superconducting coils

Methodology Applied
Scientific EffectCryogenic cooling: Cryogenics

Implementation Method 3

The magnetic yoke is in thermal contact with the thermal link from a cryogenic refrigerator and with the superconducting coils

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2644009B1Compact, cold, weak-focusing, superconducting cyclotron
Publication Date: 2016.04.06 MASSACHUSETTS INST OF TECH
  • EP2644009B1 patent drawingFigure 1~2
  • EP2644009B1 patent drawingFigure 3
  • EP2644009B1 patent drawingFigure 4

AI summary

A compact, cold, weak-focusing superconducting cyclotron can include at least two superconducting coils on opposite sides of a median acceleration plane. A magnetic yoke surrounds the coils and contains an acceleration chamber. The magnetic yoke is in thermal contact with the superconducting coils, and the median acceleration plane extends through the acceleration chamber. A cryogenic refrigerator is thermally coupled both with the superconducting coils and with the magnetic yoke.