Geonics - Model EM39 - Conductivity Borehole Probes
From Borehole Probes
The EM39 provides measurement of the electrical conductivity of the soil water matrix surrounding a borehole or monitoring well using the inductive electromagnetic technique. The unit employs coaxial coil geometry with an intercoil spacing of 50 cm to provide a substantial radius of exploration into the formation while maintaining excellent vertical resolution. Measurement is unaffected by conductive borehole fluid or the presence of plastic casing. The instrument operates to a maximum depth of 500 metres.
The combination of a large conductivity range, high sensitivity and very low noise and drift, allows accurate measurement of subsurface conditions. Typical applications include groundwater contamination monitoring, groundwater and mineral exploration, and general geotechnical investigations.
The 4-conductor EM39 probe can be used with many commercially available borehole logging systems, or with a dedicated winch and console system from Geonics.
Measurements can either be recorded with the DL600 digital data logger, or viewed in real-time using the EM39RT program with field computer.
- Measured Quantities : Apparent conductivity in millisiemens per metre (mS/m)
- Primary Field Source : Self-contained dipole transmitter
- Sensor : Self-contained dipole receiver
- Intercoil Spacing : 50 cm
- Operating Frequency : 39.2 kHz
- Measuring Ranges : 100, 1000, 10,000 mS/m
- Depth : 200 m (500 m cable optional)
- Measurement Resolution : 0.1 % of full scale
- Measurement Accuracy : ± 5 % at 30 mS/m
- Noise Levels
- Power Supply:
- 10 disposable “D” cells, or
- 12 VDC external power source
- Dimensions : Probe: 3.6 cm diameter, 163 cm length
- Probe: 2.2 kg; Console: 7 kg
- Shipping: 90 kg (2 boxes)