Improved technology using transmitting currents with short shutdown times for surface nuclear magnetic resonance

Area of Science:

• Geophysics
• Electrical Engineering
• Environmental Science

Background:

• Surface nuclear magnetic resonance (SNMR) is crucial for groundwater detection.
• Traditional SNMR systems suffer from signal loss due to dead time caused by transmitter-receiver coupling.
• This signal loss is particularly detrimental for detecting targets with short relaxation times.

Purpose of the Study:

• To address the limitations of traditional SNMR transmission systems.
• To propose and evaluate a novel transmission method for enhanced SNMR signal detection.
• To overcome issues of high resonance voltage, uncontrollable shutdown, and prolonged shutdown times in SNMR.

Main Methods:

• Developed a new transmission method utilizing untuned constant voltage-clamped technology.
• Implemented an untuned transmission topology, pulse width modulation, and constant voltage-clamping.
• Used an integer-period transmission pulse for controllable current rise and shutdown.

Main Results:

• The new method effectively controls the transmission current shutdown process, unlike traditional methods.
• Demonstrated a significant reduction in shutdown time: from 2.29 ms (traditional) to 4 µs (new method).
• The developed system improves transmitting current levels and minimizes response delays.

Conclusions:

• The untuned constant voltage-clamped technology offers a viable solution to SNMR signal loss.
• This advancement enhances the efficiency and effectiveness of groundwater detection using SNMR.
• The shortened shutdown time is critical for improving the detection of challenging subterranean targets.