Optimal bi-planar gradient coil configurations for diamond nitrogen-vacancy based diffusion-weighted NMR experiments.

Area of Science:

• Physics
• Materials Science
• Engineering

Background:

• Optically detected magnetic resonance (ODMR) with diamond nitrogen-vacancy (NV) centers offers microstructural insights via diffusion weighting.
• Bi-planar gradient coils are essential for diffusion weighting in NV-NMR, providing necessary spatial access.
• The polar tilt of the diamond NV center necessitates careful consideration of the primary magnetic field direction.

Purpose of the Study:

• To investigate optimal bi-planar gradient coil configurations for NV-NMR diffusion experiments.
• To determine the impact of coil geometry (side length, separation, orientation) on performance.
• To identify coil designs that balance sensitivity, field accuracy, and experimental integration.

Main Methods:

• Automated generation of over 500 bi-planar surface coil configurations.
• Evaluation of coil layouts based on sensitivity and magnetic field accuracy.
• Fabrication and experimental validation of a three-channel bi-planar double-layered PCB coil system.

Main Results:

• Inclined bi-planar coil orientations demonstrated superior sensitivity for transverse gradient channels compared to horizontal or vertical setups.
• Experimental validation confirmed sensitivities for transverse (x, y) and longitudinal (z) gradients.
• A relative bi-planar tilt of [Formula: see text] was identified as optimal.

Conclusions:

• The optimized bi-planar coil configuration with a [Formula: see text] tilt offers a practical compromise for NV-NMR diffusion experiments.
• This design facilitates easier coil implementation within the experimental setup.
• The findings contribute to advancing microstructural analysis using diamond NV centers.