NMR Shim Coil Design for Field Homogeneity
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Solution Overview
Problem
Existing shim coil systems for magnetic field homogenization in NMR systems face challenges in achieving high field homogeneity due to space constraints and complexity, requiring multiple coils that occupy valuable space and complicate the adjustment process.
Innovation Solution
A simplified shim coil design where wire layouts do not require cross-over points, allowing multiple coils to occupy a single layer, and the complexity is transferred to current controlling electronics and software, enabling compact and efficient field correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional shim coil systems are used to achieve magnetic field homogeneity, then field homogeneity is improved, but device complexity and space occupation increase
Solution Approach 1:
The shim coil system is divided into multiple independent linear wire groups, each contributing to different aspects of field correction. This segmentation allows for simplified individual components while achieving complex correction goals through coordinated operation of multiple simple elements.
Solution Approach 2:
Multiple wire groups with different orientations are arranged to perform multiple correction functions simultaneously. The same basic wire group structure can correct different types of field inhomogeneities by adjusting current distribution, making the system universally applicable to various magnet configurations.
2Manufacturing precision
If multiple shim coils are used to correct magnetic field inhomogeneities, then field homogeneity is improved, but the space available for samples is reduced
Solution Approach 1:
Wire groups are arranged in multiple orientations (different dimensions) within the available space, allowing the shim system to achieve three-dimensional field correction without requiring additional space in any single dimension. This multi-orientational arrangement maximizes the use of available volume.
Solution Approach 2:
Multiple wire groups are combined in a compact arrangement where they share common space and support structures. The wire groups are integrated into a unified shim assembly that occupies minimal space while providing comprehensive field correction capabilities.
3Manufacturing precision
If complex coil layouts with cross-over points are used, then specific field correction patterns are achieved, but ease of manufacture and adjustment is reduced
Solution Approach 1:
Instead of shaping the wire layout to create specific field patterns, the invention inverts the approach by using simple linear wire arrangements and achieving field correction through controlled current distribution. The complexity is shifted from mechanical geometry to electrical control.
Solution Approach 2:
The mechanical complexity of wire routing and cross-over points is replaced with an electrical control system. Current controlling electronics and software manage the current distribution among wire groups, substituting mechanical design complexity with electronic control capability.
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 design enhances magnetic field homogeneity while preserving space for samples, allowing for more precise and efficient adjustments without the need for complex coil configurations, suitable for various magnet technologies and field distributions.
Implementation Method 1
Such currents create magnetic fields around the wires. These fields are strongest near the wires and have a spatial distribution of strength and orientation that can be calculated from known physical principles.
Data Source
AI summary
A magnetic field correction system including apparatus and method for adjusting a magnetic field is provided, for example to enhance the uniformity of the field in a Nuclear Magnetic Resonance (NMR) operation. The system is of an electronic “shimming” type. The layout of the wires of the shim coils is simplified to conserve working space inside a magnet, such as an NMR magnet. The complexity of the shimming system is removed from the coils and transferred to the current controlling electronics. The current paths do not require cross-over points, and groups of parallel wires are arranged such that the wire groups have axes with different directional orientations. By deploying such shim wire groups in differently oriented axial directions, a compact shimming apparatus is provided for generating a controllable corrective magnetic field for adjusting a main original field, such as to enhance the homogeneity of the main field.