15 GSM19 Series Magnetometers - Version 7
GEM Systems, Inc. Advanced Magnetometers
For more technical information, visit www.gemsys.ca
2. THEORETICAL DESCRIPTION
The magnetic field measuring process consists of the following steps:
a) Polarization. A strong RF current is passed through the sensor creating polarization of a proton
rich fluid in the sensor.
In the case of the GSM-19 fast sampling family, polarization can be concurrent with other
intervals of measurement. Keeping the RF on all the time increases the maximum data-
sampling rate to 5 Hz.
b) Deflection. A short pulse deflects the proton magnetization into the plane of precession.
c) Pause. The pause allows the electrical transients to die off, leaving a slowly decaying proton
precession signal above the noise level.
d) Counting. The proton precession frequency is measured and converted into magnetic field
units.
e) Storage. The results are stored in memory together with date, time, and coordinates of
measurement. In base station mode, only the time and total field are stored.
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