Facilities - Magnetic Sensors
WHOI Sea Surface Magnetometers
 Woods Hole Oceanographic
Institution has two types of sea surface magnetometers for use on its
vessels. One is a Geometrics Model
866, which is a standard proton precession type of magnetometer that has been
a common sensor in the US research fleet for past few decades. Our other sensor is an IXSEA –
Magis magnetometer, which is a
nuclear precession type of magnetometer that uses the Overhauser effect. Both
of these sensors measure the absolute value of Earth's magnetic field. The
sensors are typically towed approximately 300 meters behind the ship. In
addition, the IXSEA sensor has a 6000 m depth rating for deeptow capability.
ALVIN Deep Submersible Magnetometer
 This
system was built by IFG (Instruments For Geophysics) especially for the deep
submersible ALVIN
and consists of a three-axis fluxgate vector magnetometer with an extra
z-sensor for gradiometer measurements. The system consists of two titanium
pressure housings: an electronics housing (23” long x 4.25" diam.) and a
sensor housing (28" long x 2" diam.). These housings are pressure
tested down to 6000 meters depth. Datalogging is integrated into the ALVIN data system but the
system can be operated off of any platform with power (26 Volts) and RS232
communications.
Deep ROV Magnetometer
 A small fully digital 3-axis
magnetoresistor magnetometer (Honeywell HMR2300) is now part of the National Deep Submergence Facility
(NDSF) equipment roster for Remotely-Operated
Vehicle (ROV) Jason. The
sensor is approximately 8 inches long 3 inches diameter in a titanium
pressure housing rated to 6000 meters depth. The sensor communicates via an
RS232 protocol to the datalogging system of the NDSF and other Deep Submergence
Lab vehicles.
 MiniMAG – We also have several of the above digital
magnetometer sensors with a stand-alone data logger and
battery for use on deep-towed camera systems or other vehicles.
Three-axis Fluxgate Magnetometer
A 3-axis fluxgate magnetometer (Develco Model) sensor is also used in the ABE (Autonomous Benthic Explorer)
autonomous underwater vehicle. A magnetometer system will also be installed
on the new autonomous underwater vehicle SENTRY.
Magnetometer Tests and Calibration
We tested several types of magnetometers on the WHOI Ballfield behind the
Clark Laboratories. Click here for more details
(NOT YET ACTIVE).
We also maintain a 3-axis Helmholtz coil apparatus for laboratory
calibration of sensors in the Deep Ocean Geophysics Laboratory building.
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mtivey at whoi dot edu
Last revised: 2007/5/1
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