Segmented Permanent Magnet Layout for Homogeneous MRI Fields
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Solution Overview
Problem
Magnetic resonance-based devices face challenges in generating a homogeneous and stable magnetic field using permanent magnets, leading to increased device size and cost, and mobility issues in industrial settings.
Innovation Solution
A system comprising a plurality of magnetic segments and ferromagnetic segments, each with a predetermined magnetization direction and shape, arranged to generate a magnetic field with desired strength and direction, including fluid-filled segments for optimal configuration and positioning within a predefined mesh.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If permanent magnets are used to generate a magnetic field for magnetic resonance, then a magnetic field can be produced without external power, but the magnetic field becomes non-homogeneous and insufficient for spectroscopy and imaging
Solution Approach 1:
The permanent magnet is divided into multiple segments with different magnetization directions. Each segment is magnetized in a specific direction (e.g., alternating polarities in a Halbach array configuration) to collectively produce a homogeneous magnetic field in the measurement volume, resolving the homogeneity issue while maintaining permanent magnet advantages
Solution Approach 2:
Different segments of the permanent magnet are given different local magnetization qualities and directions tailored to their specific positions. This local differentiation allows each segment to contribute optimally to the overall field homogeneity in the measurement volume, transforming the uniform magnetization limitation into a controlled spatial variation that achieves field uniformity
2Manufacturing precision
If additional elements (coils) and larger permanent magnets are added to create a homogeneous magnetic field, then magnetic field homogeneity improves, but device weight and size increase
Solution Approach 1:
The permanent magnet is segmented into multiple pieces with controlled magnetization directions, eliminating the need for additional homogenizing coils. This segmentation allows achievement of field homogeneity through geometric and magnetization pattern design rather than adding more mass
Solution Approach 2:
The magnetization direction parameter is varied across different segments of the permanent magnet (e.g., alternating directions, angled orientations in Halbach arrays). This parameter variation enables field homogeneity to be achieved through magnetic field superposition rather than increasing magnet size, thereby reducing overall device weight
3Manufacturing precision
If the size and weight of permanent magnets are increased to improve magnetic field homogeneity, then magnetic field quality improves, but manufacturing, shipment and installation costs increase
Solution Approach 1:
The large permanent magnet is divided into smaller, standardized segments that can be manufactured independently using conventional techniques. These segments are then assembled into the desired configuration, enabling modular manufacturing, easier quality control, and simplified logistics compared to producing and handling a single large magnet
Solution Approach 2:
The segmented permanent magnet design creates modular units that can be configured for different applications and field requirements. The same segment types can serve multiple purposes in different arrangements, reducing the need for custom-manufactured components and lowering overall manufacturing costs
4Reliability
If heavy and large permanent magnets are used in industrial NMR devices, then magnetic field stability improves, but personnel cannot measure fluids at various locations in the process
Solution Approach 1:
The permanent magnet system is segmented into smaller, lighter modules that can be transported and installed at different process locations. The modular design maintains field stability through precise geometric arrangement and magnetization patterns while enabling mobility and flexible deployment in industrial settings
Solution Approach 2:
The segmented permanent magnet design allows the system to be dynamically configured and relocated. Unlike a fixed large magnet, the modular segments can be assembled, disassembled, and repositioned to adapt to different measurement locations and process requirements, enabling operational flexibility
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 system achieves a stronger, more uniform magnetic field with reduced size and weight, enhancing magnetic resonance imaging and spectroscopy capabilities while minimizing magnetic fringe fields.
Implementation Method 1
A system for generating a magnetic field having a desired magnetic field strength and a desired magnetic field direction, the system including: a plurality of magnetic segments, each magnetic segment positioned adjacent to at least one of the plurality of magnetic segments, and each magnetic segment having a magnetization direction
Implementation Method 2
a plurality of ferromagnetic segments, each ferromagnetic segment positioned adjacent to at least one of the plurality of magnetic segments
Data Source
Figure 1A~1D
Figure 2
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AI summary
Generally, a system for generating a magnetic field having a desired magnetic field strength and/or a desired magnetic field direction is provided. The system can include a plurality of magnetic segments and/or a plurality of ferromagnetic segments. Each magnetic segment can be positioned adjacent to at least one of the plurality of magnetic segments. Each ferromagnetic segment can be positioned adjacent to at least one of the plurality of magnetic segments. A size, shape, positioning and/or number of magnetic segments and/or ferromagnetic segments in the system, as well as a magnetization direction of the magnetic segments can be predetermined based on, for example, predetermined parameters of the system and/or based on a desired application of the system.