Segmented Superconducting Electromagnets for Lower Quench Voltage

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Solution Overview

Problem

Conventional superconducting electromagnets used in charged particle therapy require high stored energy for generating continuous magnetic fields, leading to increased voltage and risk of quench, which can damage the coils due to thermal loads and leakage magnetic fields.

Innovation Solution

The design incorporates multiple superconducting electromagnets with adjustable magnetic flux densities and orientations to reduce stored energy and quench voltage, using a sector-shaped vacuum chamber and power supply management to control current distribution and minimize unnecessary magnetic fields.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a superconducting electromagnet generates an even, high magnetic field to enable continuous irradiation angle, then the magnetic field uniformity is improved, but the stored energy increases leading to higher quench voltage and leakage magnetic field

Engineering Contradiction:
Improvemagnetic field uniformityVSAvoidstored energy
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent divides the single superconducting electromagnet system into multiple separate superconducting electromagnets (first and second superconducting electromagnets). Each electromagnet generates magnetic fields for specific angular ranges, eliminating the need for one large electromagnet to cover all angles. This segmentation reduces the stored energy of each individual electromagnet while maintaining the capability for continuous angular irradiation through coordinated operation of multiple units.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs dynamic switching between multiple superconducting electromagnets based on the required irradiation angle. The system selectively activates specific electromagnets according to the angular position requirements, allowing the magnetic field generation to be dynamically adjusted. This dynamic operation enables continuous angular coverage while keeping each electromagnet's stored energy at manageable levels.

Inventive Principle:
Principle #15Dynamics

2Force

If the stored energy of the superconducting electromagnet is increased to maintain high magnetic field, then the magnetic field strength is improved, but the quench voltage increases causing potential coil damage

Engineering Contradiction:
Improvemagnetic field strengthVSAvoidcoil safety
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

By segmenting the magnetic field generation function across multiple superconducting electromagnets, each unit operates at lower stored energy levels. This segmentation inherently reduces the quench voltage of each individual electromagnet, lowering the risk of coil damage during quench events while collectively providing the required magnetic field strength for particle beam manipulation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent incorporates protective resistors connected in parallel to each superconducting coil as a preemptive safety measure. These protective components are pre-installed to handle quench events before they can damage the coils. The lower quench voltage achieved through segmentation works in conjunction with these protective measures to enhance overall system reliability and coil safety.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If a single superconducting electromagnet is used to cover all irradiation angles, then the device complexity is reduced, but the leakage magnetic field increases affecting surrounding equipment

Engineering Contradiction:
Improveelectromagnet configurationVSAvoidleakage magnetic field
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent divides the magnetic field generation into multiple separate superconducting electromagnets, each responsible for specific angular sectors. This segmentation localizes the magnetic field generation, reducing the overall leakage magnetic field in any given direction compared to a single large electromagnet. The modular configuration allows better spatial management of magnetic fields while maintaining functional capability for continuous angular irradiation.

Inventive Principle:
Principle #1Segmentation

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 configuration allows for continuous charged particle beam irradiation at various angles while reducing stored energy, quench voltage, and leakage magnetic fields, enhancing the safety and efficiency of the superconducting electromagnet apparatus.

Implementation Method 1

a superconducting electromagnet configured to converge a charged particle beam, which is incident from a wide range of deflection angles, to the isocenter

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a superconducting coil configured to generate a plurality of even magnetic fields

Methodology Applied
Scientific EffectSuperconductivity: Superconductivity

Implementation Method 3

since a magnetic flux corresponding to the high magnetic field is required to be confined in the space thereof

Methodology Applied
Scientific EffectMagnetic flux confinement: Magnetic Field

Implementation Method 4

an electric resistance occurs in a superconducting coil of the superconducting electromagnet. When coil current flows therein, a local rise in the temperature occurs

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3888746B1Superconducting electromagnet apparatus and charged particle irradiation apparatus
Publication Date: 2023.09.20 B DOT MEDICAL INC
  • EP3888746B1 patent drawingFigure 1
  • EP3888746B1 patent drawingFigure 2
  • EP3888746B1 patent drawingFigure 3

AI summary

The present invention relates to a superconducting electromagnet apparatus having a group of superconducting electromagnets including a first superconducting electromagnet and a second superconducting electromagnet arranged adjacent to the first superconducting electromagnet. Effective magnetic field regions generated by the first and second superconducting electromagnets, respectively, are formed to satisfy predetermined relational equations.