Transformer-coupled NMR probe.

Area of Science:

• Magnetic Resonance
• Electrical Engineering
• Physics

Background:

• Conventional Nuclear Magnetic Resonance (NMR) probes often rely on capacitor coupling for impedance matching.
• Achieving efficient energy transfer and broad frequency operation in NMR systems can be challenging.
• Existing methods may disturb the sensitive magnetic fields crucial for NMR measurements.

Purpose of the Study:

• To develop and evaluate a novel NMR probe circuit utilizing a transformer with a ferromagnetic core.
• To improve impedance matching for efficient energy transfer between the sample coil and NMR spectrometer.
• To enable wide frequency range operation without manual tuning for NMR applications.

Main Methods:

• Designed an NMR probe circuit incorporating a transformer with a ferromagnetic core.
• Implemented impedance matching using the transformer's coupling properties.
• Tested the probe's performance and frequency range, comparing it to conventional capacitor-coupled circuits.

Main Results:

• The transformer-coupled NMR probe demonstrated comparable performance to capacitor-coupled circuits, with losses below 1 dB.
• The probe operated effectively over a wide frequency range (500 kHz-5 MHz) without requiring matching adjustments.
• The ferromagnetic core provided strong, confined coupling, ensuring efficient energy transfer without disturbing the B(1) field.

Conclusions:

• The proposed transformer-coupled NMR probe offers a viable alternative to conventional designs.
• Its wide frequency operation and efficient energy transfer make it suitable for low-field mobile NMR.
• Potential applications include multi-frequency NMR measurements like imaging, relaxation, diffusion, and Nuclear Quadrupole Resonance (NQR).