
To measure the Earth's magnetic field, a strong polarizing field is applied by sending a direct current through the coil. This polarizing field is oriented at a large angle to the Earth's field direction, which causes the protons in the liquid to be displaced out of the Earth's field. When the polarizing field is switched off, the protons return to their original alignment and precess for a short time around the direction of the Earth's ambient field to re-align themselves with the normal magnetic flux density. The frequency of this precession is related to the absolute Earth field through a well-known constant, the gyrometric ratio of the proton. Dividing the measured frequency by the gyrometric ratio gives the value of the Earth's total field.
One of the advantages of proton magnetometers is that the orientation of the sensor is not critical. The only requirement is that the polarizing field should make a sufficiently great angle with the direction of the Earth's field. Additionally, unlike fluxgate magnetometers, which can measure the field continuously, proton magnetometers give a series of discrete measurements at intervals of a few seconds due to the polarizing and relaxing time taken by the protons.
Proton magnetometers are commonly used in various applications, including geophysics, mineral exploration, archaeological surveys, and m i l i t a r y applications. They are highly sensitive, stable, and reliable, making them an essential tool in the field of magnetometry.
Technical Specification
Measurement range | 30,000nT~70,000nT |
Resolution | 0.1nT |
Precision | ±1nT |
Allowed gradient | vertical gradient≤2000nT/m |
Horizontal gradient≤1500nT/m | |
LCD lattice | 192*64 |
Data stored | 4005 (in daily variation method) 2670 (in manual method) |
Working temperature | -20°C ~+50°C |
Working humidity | ≤90% (30°C) |
Power source | lithium battery, 15.5V~16.8V/3.8Ah, work 10 hours continuously |
Mainframe size | 210*80*200mm |
The 3 working modes of proton magnetometer includes:
1) Base station mode

2) Walking mode

The image shows a back-pack mounted configuration with console, sensor, supporting poles, cables
3) Horizontal/Vertical gradient mode
