NMR Probehead Transceiver Coil Width Variation
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Solution Overview
Problem
NMR probe heads with cross-coil arrangements face challenges in achieving high quality factor and transparency for RF magnetic fields, as the magnetic field of one coil is often disturbed or partially shielded by the conductor of the other coil, leading to suboptimal performance in multinuclear MAS measurements.
Innovation Solution
The transceiver coil in the NMR probe head features a conductor width that varies periodically within each winding, with regions of minimum and maximum width optimized to enhance transparency and quality factor, allowing for better alignment and superposition of RF magnetic fields without compromising the coil's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the clearances between the windings of the solenoid coil are made sufficiently large to achieve transparency for the alternating magnetic field at the 1H frequency, then the transparency for RF magnetic fields is improved, but the quality factor of the solenoid coil becomes lower than the optimum possible
Solution Approach 1:
The patent applies local quality by varying the conductor width along the winding path. Specifically, the conductor width is reduced in regions where transparency for external RF magnetic fields is needed (allowing field penetration), while maintaining larger width in other regions to preserve inductance and quality factor. This local variation resolves the contradiction by optimizing different sections of the same coil for different functions.
Solution Approach 2:
The patent changes the geometric parameter of conductor width along the winding path. By making the conductor width variable rather than constant, the coil can simultaneously achieve sufficient transparency (where width is reduced) and maintain high quality factor (where width is larger). This parameter change allows the coil to satisfy both conflicting requirements that cannot be met with uniform dimensions.
2Adaptability or versatility
If a cross-coil arrangement is used to excite different nuclei, then the versatility of the NMR probe head is improved, but the magnetic field of one coil is disturbed or partially shielded by the conductor of the other coil
Solution Approach 1:
The variable conductor width creates local transparency regions that allow magnetic fields from orthogonal coils to penetrate the measurement volume without significant shielding. This local optimization of conductor geometry reduces interference between cross-coils while maintaining the versatility of multinuclear excitation.
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 achieves a higher transparency for RF magnetic fields while maintaining a high quality factor, enabling more efficient NMR measurements by minimizing interference between coils and optimizing signal-to-noise ratio, particularly in cross-coil arrangements.
Implementation Method 1
a first transceiver coil for generating a first RF magnetic field B1, wherein the first transceiver coil comprises an electrical conductor with multiple windings about a longitudinal axis Z'
Implementation Method 2
the conductor width W decreases and increases at least twice and increases at least twice within each winding... achieves a higher transparency for RF magnetic fields while maintaining a high quality factor
Data Source
AI summary
An NMR probe head has a transceiver coil arrangement with a first transceiver coil for generating a first RF magnetic field B1, wherein the first transceiver coil comprises an electrical conductor having multiple windings about a longitudinal axis Z′, and wherein the electrical conductor of the first transceiver coil is designed as a strip-shaped conductor with a conductor width W that decreases at least twice and increases at least twice within each winding. The NMR probe head thereby has a transceiver coil that has maximum quality factor with simultaneous transparency to other RF magnetic fields that may be radiated.