Site Characterization for Monitoring Applications Using Overhauser Magnetometer
Magnetometers and gradiometers are being used increasingly in monitoring roles (i.e. to monitor atmospheric magnetic disturbances, volcanoes or earthquakes).
The Overhauser magnetometer, with its unique set of features, represents a pillar of modern magnetometry of the Earth's magnetic field. Its sensitivity matches costlier and less convenient cesium magnetometers, for example. The Overhauser magnetometer also offers superior omnidirectional sensors; no dead zones; no heading errors; or warm-up time prior to surveys; wide temperature range of operation (from -40 to 50 degrees Celsius standard and -55 to 60 degrees Celsius optional); rugged and reliable design; and virtually no maintenance during its lifetime. Other advantages include high absolute accuracy, rapid speed of operation (up to 5 readings per second), and exceptionally low power consumption.
Overhauser magnetometers use proton precession signals to measure the magnetic field – but that's where the similarity with the proton precession magnetometer ends.
Overhauser magnetometers were introduced by GEM Systems, Inc. following R&D in the 80's and 90's, and are the standard for magnetic observatories, long term magnetic field monitoring in volcanology, geophysical ground and vehicle borne exploration, and marine exploration….more at GEM Systems, Inc.