Optimized Weight Low-Frequency Search Coil Magnetometer for Ground-Airborne Frequency Domain Electromagnetic Method

Area of Science:

• Geophysics
• Electromagnetic Methods
• Sensor Technology

Background:

• Traditional air coil sensors in ground-airborne frequency domain electromagnetic (GAFDEM) methods exhibit low sensitivity in the crucial low-frequency band.
• This limitation hinders the detection of deep geological structures and results in inaccurate apparent resistivity interpretations.
• Existing sensors face challenges in achieving both sensitivity and reduced weight for effective deep detection.

Purpose of the Study:

• To develop an optimized weight magnetic core coil sensor for enhanced GAFDEM surveys.
• To improve low-frequency signal detection sensitivity for more accurate deep subsurface analysis.
• To address the limitations of current air coil sensors in GAFDEM applications.

Main Methods:

• Designed a novel sensor incorporating a cupped flux concentrator to maintain magnetic gathering capacity while reducing weight.
• Optimized the core coil winding into a rugby ball shape to maximize magnetic field concentration at the core center.
• Conducted laboratory and field experiments to validate sensor performance and compare it with existing technologies.

Main Results:

• The developed optimized weight magnetic core coil sensor demonstrates high sensitivity in the low-frequency band.
• Experimental results confirm superior performance compared to conventional air coil sensors.
• The new sensor enables more accurate detection of signals from deeper targets.

Conclusions:

• The optimized weight magnetic core coil sensor is a significant advancement for GAFDEM.
• It effectively overcomes the low-frequency sensitivity limitations of existing sensors.
• This technology promises more reliable and accurate deep subsurface exploration using GAFDEM.