Modular Superconducting Coils for NMR Magnet Homogeneity

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Solution Overview

Problem

Current superconducting magnets for high-field NMR and MRI applications face challenges in achieving spatial homogeneity and reducing external magnetic fields, leading to increased costs and complexity in manufacturing and handling.

Innovation Solution

A device comprising modular superconducting coils with a double wafer design and sinusoidal transition sections, arranged coaxially with compensation coils to minimize external field leakage and optimize internal field homogeneity, allowing for reduced material usage and improved manufacturing flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the magnetic field strength in the interior volume of interest is increased, then the field intensity in the examination volume is improved, but the field in the space outside the magnet increases, requiring larger shielding volumes

Engineering Contradiction:
Improvefield intensityVSAvoidshielding volume
Core Design Contradiction:
Use of energy by moving objectVSVolume of stationary object

Solution Approach 1:

The magnet system is divided into multiple independent modules, each producing a controlled magnetic field component. By segmenting the magnet into discrete units with specific geometries and current distributions, the patent achieves the desired internal field intensity while controlling the external field decay, reducing the required shielding volume.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs modules with specific three-dimensional geometries (cylindrical, spherical, or toroidal shapes) that exploit spatial dimensionality to achieve rapid external field decay. The modular arrangement in three-dimensional space allows the magnetic field to be concentrated in the interior volume while decaying quickly outside, reducing shielding requirements.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If traditional layered windings with large mass coils are used, then the magnetic field homogeneity is achieved, but the handling and assembly during manufacturing become difficult

Engineering Contradiction:
Improvefield homogeneityVSAvoidhandling and assembly
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The magnet is constructed from multiple small-mass modular elements that can be easily handled and assembled. Each module is designed to produce a specific magnetic field contribution, and by combining many such modules, the patent achieves the required field homogeneity without the manufacturing difficulties associated with large single-piece coils.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple modular elements are combined to form the complete magnet system. Each module contributes to the overall magnetic field, and their collective arrangement achieves the desired homogeneity. This merging of many small, manageable units replaces the traditional single large-coil approach, improving manufacturability.

Inventive Principle:
Principle #5Merging (Combining)

3Use of energy by moving object

If the number of superconducting strands is increased to achieve required field values, then the field intensity is improved, but the conductor mass and manufacturing complexity increase

Engineering Contradiction:
Improvefield valueVSAvoidconductor mass
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The total superconducting conductor required is distributed across multiple modular elements rather than concentrated in a single large conductor. Each module contains a manageable number of superconducting strands, and the modular architecture allows the system to achieve high field values without requiring any single component to be excessively complex or massive.

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

The solution enables the production of high-field magnets with enhanced internal homogeneity and reduced external field exposure, simplifying manufacturing and handling while minimizing material usage and operational costs.

Implementation Method 1

an arrangement of superconducting coils arranged around a longitudinal axis (z) of said area of interest, which area of interest lies within said arrangement of superconducting coils

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

each modular element comprising a conductor of rectangular section made of superconducting material

Methodology Applied
Scientific EffectSuperconductivity: Superconductivity

Data Source

PatentEP1969384B1Method and device for generating a homogeneous magnetic field in an area of interest, especially for nmr imaging
Publication Date: 2013.02.13 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP1969384B1 patent drawingFigure 1~3
  • EP1969384B1 patent drawingFigure 4~6
  • EP1969384B1 patent drawingFigure 7~9

AI summary

The device for generating a homogeneous magnetic field in an area of interest, especially for nuclear magnetic resonance and magnetic resonance imaging, comprises an arrangement of superconducting coils placed around a longitudinal axis (z) of this area of interest. This arrangement of coils comprises at least one stack of a set of modular elements (8) distributed along the longitudinal axis (z), each modular element (8) comprising a conductor of rectangular cross section made of a superconducting material wound in a continuous manner in the form of a double-pancake coil. The double-pancake coil comprises a first plane single pancake coil (10) in the form of a spiral, a second plane single pancake coil (20) in the form of a spiral juxtaposed with the first single pancake coil (10) parallel to the latter, and a transition section (30) without an internal join between the first and second single pancake coils (10, 20). Each single pancake coil (10, 20) has a connection end (11, 21) located in the external peripheral part of the pancake coil and the transition section (30) provides, along the longitudinal axis (z), a shift at least equal to the transverse dimension of the conductor along this axis.