Geometrics G-822A Caesium “Cs” Vapour Magnetometer

  • Airborne and Vehicle Applications with Multi-Sensor Array Capability
  • Automatic Hemisphere Switching
  • Optional G-823A configuration with CM-201 Internal Mini-Counter (up to 8 sensors) for post-acquisition compensation
  •  Very low heading error – ±0.15 nT over entire 360° Equatorial and Polar spins
  • Geometrics offers complete turnkey systems including Birds, Stingers, Wingtip installation accessories as well as digital data acquisition systems, flight path recovery, GPS navigation, gamma ray spectrometers, VLF EM , post-acquisition data processing software and training
 A single coaxial cable of up to a standard 10 meters length supplies both 28 VDC power and Larmor signal transmission from the sensor driver electronics. The interconnect cable from the driver/electronics to the sensor may be supplied in various lengths (see specs on reverse) with a standard length of 13.5 ft.


Operating Principle Self-oscillating split-beam Cesium Vapour (non-radioactive)
Operating Range 20,000 to 100,000 nT
Operating Zones The earth’s field vector should be at an angle greater than 6º from the sensor’s equator and greater than 6º away from the sensor’s long axis. Automatic hemisphere switching.
Sensitivity < 0.001 nT/√Hzrms. Typically 0.003 nT P-P at a 0.1 second sample rate 0.02 nT P-P for CM-201
Heading Error ± 0.15 nT (over entire 360º polar and equatorial spin)
Absolute Accuracy < 3 nT throughout range
Output Cycle of Larmor frequency = 3.498572 Hz/nT, 2 V P-P coupled through the sensor power input
Sensor 60.32mm diameter, 146mm long, 339 g – any orientation in 177.8mm diameter stinger
Sensor Electronics 63.5mm diameter, 279.4mm long, 623 g
Sensor to Electronics Standard 4.1 m. Other lengths available from 0.75m at 1m increments with connector on electronics end. Note: Cable lengths are approximate due to cable dielectric variations
Sensor Electronics to Counter Standard 10 m, up to 50 m (Coax with signal superimposed on power, requires decoupler board or box.)
Operating Temperature -35°C +50°C
Storage Temperature -45°C +70°C
Altitude Up to 9,000m
Weatherproof O-Ring sealed for operation in rain or 100% humidity
Power 24 to 32 VDC, 1 amp at turn-on and 0.5 amp thereafter
Standard Power/Larmor coaxial cable (electronics to counter), standard length 10m, maximum 50m, spare O rings, operation manual and carrying/storage case
Signal/Power Decoupler, board or multi-channel box Separates the Larmor signal from the power (28 V) to enable connection to Customer supplied counter
Internal Decoupler P/N 27504 – up to two sensor installation
External Decoupler P/N 27560 – three and four sensor installation
Internal CM-221 Counter See G-823 A Data Sheet
Stinger, Wingtip, Bird  Contact GeoResults for complete system integration information


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