Product Category
Magnetometers & Gradiometers
Proton precession, Overhauser, and cesium vapor magnetometers from Geometrics, GEM Systems, and Scintrex, for mineral exploration, unexploded ordnance (UXO) detection, and archaeological survey. Available New, Refurbished, Absolute Certified, or Surplus.
What is a Geophysical Magnetometer?
A geophysical magnetometer measures the strength of the Earth's total magnetic field at a point, expressed in nanotesla (nT). Local geology, buried ferrous objects, and mineral deposits with strong magnetic susceptibility (notably magnetite and other iron-bearing minerals) all produce small, measurable perturbations in the ambient field. By walking, driving, or flying a magnetometer over a survey area and logging field strength against position, geophysicists can map these anomalies to infer subsurface structure, locate buried metal, or identify mineralized zones.
Sensor Technologies
- Proton precession: Measures the Larmor precession frequency of protons in a hydrocarbon-rich fluid after being polarized by a coil. Robust, absolute (no drift), moderate sensitivity (~0.1–1 nT), and the traditional workhorse for exploration and archaeology.
- Overhauser effect: A refinement of proton precession that uses RF polarization of free electrons to continuously polarize the proton population, enabling much faster sampling rates (up to several Hz) and lower power consumption than classical proton precession sensors, at similar or better sensitivity.
- Cesium vapor (optically pumped): Uses optical pumping of cesium atoms to achieve the highest available sensitivity (down to ~0.001 nT) and very high sample rates, at higher cost. Preferred for UXO discrimination and high-resolution archaeological and geological mapping.
Configurations
- Total-field (single-sensor): Measures the magnitude of the total magnetic field vector at one point — the standard configuration for regional and reconnaissance surveys.
- Gradiometer (dual-sensor): Two sensors mounted at a fixed vertical or horizontal separation measure the spatial gradient of the field. Gradiometers largely cancel diurnal variation and regional trends without a stationary base station, and sharpen the response to shallow, localized targets — the standard configuration for UXO and archaeological work.
- Platform: Walking (backpack/cart), vehicle-towed, drone/UAV-mounted (e.g. MagArrow-style lightweight sensors), and marine/towed-fish configurations are all available depending on survey scale and terrain.
Specification Considerations
Key specifications to compare when selecting a magnetometer include sensitivity/resolution (nT), absolute accuracy, sampling rate (Hz), heading error (sensitivity to sensor orientation — critical for cesium sensors), dead zones (orientation ranges where a proton or Overhauser sensor cannot operate), and integrated GPS/GNSS for position-tagged data logging. A base station magnetometer is typically deployed alongside a total-field roving sensor to correct for diurnal magnetic variation.
Magnetometer Brands We Supply
| Brand | Origin / Parent | Known For | Typical Application |
|---|---|---|---|
| Geometrics | Independent (USA) | Proton precession & Overhauser magnetometers, lightweight drone-mounted sensors, gradiometer configurations | Mineral exploration, UXO, archaeology |
| GEM Systems | Independent (Canada) | Overhauser magnetometers, multi-sensor gradiometer arrays, base station systems | Exploration, environmental, archaeology |
| Scintrex | Independent (Canada) | Proton precession magnetometers, rugged field instruments for exploration geophysics | Mineral & groundwater exploration |
Condition Tiers for Magnetometers
Factory New
Sealed sensor and console direct from the manufacturer, current firmware, full OEM warranty and factory sensitivity certificate.
Refurbished
Sensor housing, cable, and console inspected; battery and connectors replaced as needed; function-tested against a known field reference before dispatch.
Absolute Certified
Full bench inspection plus sensitivity and noise-floor verification against a traceable reference field, with a calibration certificate issued at handover.
Surplus
Decommissioned or excess survey-company inventory, sold functional and as-is — a cost-effective source of spare sensors and consoles.
Frequently Asked Questions
What's the difference between a total-field magnetometer and a gradiometer?
A total-field magnetometer uses a single sensor to log the absolute strength of the Earth's magnetic field, which must then be corrected for diurnal drift using a stationary base station. A gradiometer uses two sensors at a fixed separation and measures the difference between them, which largely cancels diurnal variation in real time without a base station and emphasizes shallow, localized anomalies — making it the standard choice for UXO surveys and archaeological prospection.
Can a refurbished magnetometer still achieve original sensitivity specifications?
In most cases, yes. Magnetometer sensors have no moving parts and, barring physical damage to the sensor housing or cable, degrade very little with age. Our Refurbished and Absolute Certified units are function-tested and, for Absolute Certified equipment, verified against a traceable field reference — so buyers can expect performance close to the original factory specification.
Do you supply both walking and drone-mounted magnetometer configurations?
Yes. We source backpack/cart-mounted walking systems, vehicle-towed arrays, and lightweight sensors designed for UAV/drone integration, across all four condition tiers. Tell us your survey platform and target depth/resolution and we'll recommend the right sensor technology and configuration.