Halbach Magnet Array Layout for Compact NMR Field Homogeneity
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Solution Overview
Problem
Conventional Halbach magnet configurations face challenges in achieving strong, uniform magnetic fields in compact NMR devices due to space constraints and difficulties in controlling magnetic field inhomogeneities, particularly in compact designs where traditional shim coil systems are impractical.
Innovation Solution
The modified Halbach magnet configurations incorporate polyhedral magnets arranged in a Halbach cylinder configuration alongside a non-Halbach configuration, with subsets of magnets having different coercivities and magnetization orientations to enhance magnetic field strength and uniformity, and include lateral displacement of magnets to counteract magnetic field gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional shim coil systems are used to correct magnetic field inhomogeneities, then field uniformity is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent extracts the shimming function from separate shim coils and integrates it directly into the Halbach magnet array by modifying the magnetization vectors of individual magnets. This eliminates the need for separate shim coil systems while maintaining field uniformity correction capabilities.
Solution Approach 2:
The patent merges the field generation function and field uniformity correction function into a single integrated Halbach magnet array structure. By combining these functions, the system reduces overall device complexity and eliminates the need for separate shim coil systems.
2Power
If more magnets are added to the Halbach array to improve field strength, then magnetic field strength increases, but manufacturing complexity and cost increase
Solution Approach 1:
The patent applies local quality by assigning different magnetization vectors to specific magnets based on their positions within the Halbach array. This allows each magnet to contribute optimally to the overall field strength while maintaining manufacturability through systematic variation rather than random complexity.
Solution Approach 2:
The patent employs asymmetry in the magnetization vector orientations within the Halbach array to maximize field strength. By using non-uniform magnetization patterns asymmetrically distributed across the magnet positions, the system achieves enhanced field strength without requiring proportional increases in 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 approach allows for increased magnetic field strength while maintaining the cost-effectiveness and manufacturability of cylindrical and spherical Halbach configurations, improving field homogeneity and reducing demagnetizing forces.
Implementation Method 1
a first plurality of polyhedral magnets arranged in a Halbach cylinder configuration... the plurality of polyhedral magnets at least partly enclosing a testing volume
Implementation Method 2
Halbach magnet configurations incorporate polyhedral magnets arranged in a Halbach cylinder configuration
Data Source
AI summary
A magnet array is disclosed comprising a plurality of polyhedral magnets arranged in a Halbach cylinder configuration, the centers of individual ones of the plurality of polyhedral magnets being arranged substantially in a plane in a magnet rack, the plurality of the polyhedral magnets at least partly enclosing a testing volume, and comprising a first plurality of polyhedral magnets arranged in a Halbach cylinder configuration and a second plurality of polyhedral magnets arranged in a non-Halbach configuration. In another aspect, a magnet array is disclosed comprising a first subset and a second subset of polyhedral magnets having different coercivities. In yet another aspect, a magnet array is disclosed wherein a subset of the centers of the individual ones of the plurality of polyhedral magnets are laterally displaced from a nominal position in the magnet rack to counteract a magnetic field gradient of the magnet array.