Halbach Ring Magnetic Field Generator for MPI
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Solution Overview
Problem
Current magnetic-field generating devices for Magnetic Particle Imaging (MPI) require complex and energy-intensive coil arrangements to shift and rotate field-free lines (FFLs) within a scan plane, leading to material wear and handling challenges, especially when using field-free lines instead of field-free points.
Innovation Solution
A magnetic-field generating device comprising two structurally identical Halbach rings of the Halbach order k=2, arranged symmetrically with a center-point distance greater than the ring width and outside diameter, allowing for the generation of a field-free line in a plane of symmetry that can be shifted and rotated without the need for rotating coil pairs, utilizing a Helmholtz coil pair for a homogenous magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a coil arrangement is used to generate and shift the field-free line in the scan plane, then the FFL can be positioned and oriented, but the device complexity and energy consumption increase due to rotating coil pairs
Solution Approach 1:
The patent replaces the mechanical coil arrangement system with a magnetic field generation system using permanent magnets in Halbach configuration. Instead of using rotating coils to generate and position the FFL, the invention uses stationary permanent magnets that inherently generate the desired magnetic field pattern, eliminating mechanical rotation and associated complexity.
Solution Approach 2:
The permanent magnets in Halbach configuration self-generate the required magnetic field pattern including the FFL without requiring external power or active control systems. The magnetic field is inherently produced by the magnet arrangement itself, eliminating the need for powered coil systems that require energy input and complex control mechanisms.
2Adaptability or versatility
If rotating coil pairs are used to shift and rotate the FFL, then the FFL can be repositioned in the scan plane, but material wear and handling challenges occur
Solution Approach 1:
The patent eliminates the mechanical rotation system by using permanent magnets that generate the FFL through their inherent magnetic field configuration. The Halbach array of permanent magnets creates the field pattern without any moving parts, replacing the unreliable rotating coil mechanism with a stationary, wear-free magnetic field generation system.
3Ease of operation
If coil arrangements are used to generate the homogenous magnetic field for FFL shifting, then the FFL can be shifted in the scan plane, but energy consumption increases
Solution Approach 1:
The permanent magnets in Halbach configuration self-generate the magnetic field including the FFL without requiring external power input. The system uses the inherent magnetic properties of the permanent magnets to create and maintain the field pattern, eliminating the continuous energy consumption required by powered coil systems.
Solution Approach 2:
The patent replaces the energy-intensive electromagnetic coil system with a passive permanent magnet system. The Halbach configuration of permanent magnets generates the required magnetic field pattern without electrical power input, substituting active electromagnetic field generation with passive magnetic field generation.
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
Enables simple, energy-saving generation and repositioning of the FFL in the scan plane, reducing the complexity and energy consumption associated with coil movements, while maintaining a uniform magnetic field gradient suitable for MPI applications.
Implementation Method 1
The magnetic field that has been generated exhibits a field-free line having a predetermined magnetic-field gradient in a predetermined plane
Implementation Method 2
Magnetic-field generating device that exhibits in particular permanent magnets in a Halbach arrangement
Implementation Method 3
utilizing a Helmholtz coil pair for a homogenous magnetic field
Implementation Method 4
exhibits a field-free line having a predetermined magnetic-field gradient
Data Source
AI summary
Disclosed is a device for simply creating a magnetic gradient field having a field-free line (FFL). The device comprises two ring-shaped Halbach arrays formed of permanent magnets, and preferably also a coil arrangement for electrically generating a homogeneous magnetic field for shifting the FFL in a predetermined plane. The FFL can be rotated together with the Halbach array in the plane, without the coil arrangement having to be rotated or moved. The invention is suitable for effective construction of a scanning device for magnetic particle imaging (MPI).