NMR Coil Arrangement With Crossed Leads For Rectangular Field Profile
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Solution Overview
Problem
Existing nuclear magnetic resonance (NMR) coil arrangements face challenges in generating a high-frequency magnetic field profile that is rectangular and steep on both sides, particularly in high-resolution NMR spectroscopy, leading to inefficient solvent suppression and shimming due to deviations in resonance frequency across the measurement sample.
Innovation Solution
The coil arrangement is modified by adjusting the angle α between the B1 and B2 fields to 180° ± Δα, where Δα < 90°, with at least two electrical leads having a crossing point or being electromagnetically coupled to ring elements in the lower region, reversing the B2 field direction and creating zero crossings at the edges, allowing for efficient HF shielding and optimized signal line shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional coil arrangements with parallel leads are used, then the coil structure is simple and easy to manufacture, but the high-frequency magnetic field profile lacks steep edges and rectangular shape
Solution Approach 1:
The patent applies inversion by crossing the supply lines in opposite directions, which reverses the direction of the B2 field generated by the leads. This causes the B2 field to oppose and cancel the B1 field in the edge areas, creating zero crossings and achieving the desired rectangular field profile with steep edges.
Solution Approach 2:
The patent changes the geometric parameter of the supply line arrangement from parallel to crossed configuration. This parameter change fundamentally alters the magnetic field distribution, transforming the field profile from conventional gradual edges to the desired rectangular shape with steep transitions.
2Measurement precision
If leads are routed parallel to each other, then the coil arrangement is simple, but solvent suppression and shimming efficiency are reduced due to non-rectangular field profile
Solution Approach 1:
By inverting the lead routing configuration to crossed leads, the patent generates a B2 field that opposes the B1 field in edge regions. This creates the rectangular field profile necessary for efficient solvent suppression and improved shimming, directly enhancing measurement precision.
3Shape
If the angle α between B1 and B2 fields is not optimized, then the coil configuration is simple, but zero crossings are not achieved at the edges
Solution Approach 1:
The crossed lead arrangement inverts the B2 field direction relative to conventional parallel routing. This inversion achieves the critical angle α between B1 and B2 fields that produces zero crossings at the edges, creating the desired magnetic field distribution without requiring additional components.
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 configuration generates a high-frequency magnetic field with zero crossings or minimum magnitude in the edge areas, enabling efficient solvent signal suppression and simplified shimming, resulting in improved NMR signal resolution and reduced line broadening.
Implementation Method 1
through which current flows during operation, which during operation generates a high-frequency magnetic B 1 field at the location of a test sample
Implementation Method 2
connected to at least two electrical supply lines through which in-phase currents flow during operation and generate a high-frequency magnetic B 2 field in the test sample
Data Source
Figure 1a~1e
Figure 1f~2d
Figure 3a~4c
AI summary
A nuclear magnetic resonance coil arrangement with at least one planar or cylindrical coil (18) carrying current during operation, which generates a high-frequency magnetic B1 field at the location of a measurement sample (16) oriented parallel to an x-axis, and which is connected to a tuning network with at least two electrical leads (11) carrying phase-matched currents during operation and generating a high-frequency magnetic B2 field in the measurement sample (16) whose orientation forms an angle α with the direction of the B1 field, is characterized in that the angle α is given by: α = 180° ± Δα, where Δα < 90°. This allows the generation of a B1 field profile that is as rectangular as possible and particularly steep on both sides.