FGM650 Gradiometer

FGM650 Gradiometer

The FGM650/10 is a vertical difference magnetometer with a standard measurement range of ±10 μT.


Sensor Technology:
Application Type:
Archaeology, Geophysics and Geology


The FGM650/10 is a vertical difference magnetometer with a standard measurement range of ±10 μT. It is used in various surface-, underwater- and borehole measurement systems for the detection of magnetic objects, interference fields and signatures in the ground.

The FGM650/10 consists of two single-axis Fluxgates that are aligned vertically to each other in a distance of 650 mm. This alignment allows for differential measurements thus suppressing the Earths magnetic field and global disturbances. The result is an improved detection of object signatures in the ground.

The FGM650/10s rugged aluminum housing makes the sensor also a suitable device for borehole measurements e.g. with the SENSYS MAGNETO® BM2 DISTLOG system with distance measurement.

Also available: FGM650/3 which features a measurement range of ±8 μT for applications in archaeology and geophysics. Thus even finest ground structures can be scanned.


Maximum ambient field±75 µT
Specified measurement rangeFGM650/10: ±10 µT
FGM650/3: ±8 µT
Sensor element spacing650 mm
Point of reference393mm*/4mm**
Declination±5 nT
Noise<40 pT rms /?Hz@1 Hz
Cut off frequency (bandwidth)20Hz (DC...20Hz)
Temperature drift<0.3 nT/K
Drift over timet.b.d.
Compensation rangen.a.
Sensitivity gradiometerFGM650/10: 0.5 V/µT
FGM650/3: 0.6 V/µT
Sensitivity absolute5.0V / 75 µT
OutputFGM650/10: ±5V full scale
FGM650/3: ±4,8V full scale
Power supply±7,0 V to ±15,0 V
Current consumption±26 mA
Operating temperature-20°...+70°C
Storage temperature-40°...+80°C
Dimensions35 mm diameter x ca. 850 mm length (without connector)
Weight0.72 kg
IP codeIP68 down to 100m available
* measured from edge between head and tube** from symmetry axis

Service and Contact

Your inquiry