The Promis device is a multi-frequency, multi-spacing 3 component slingram type EM System for sounding and profiling the soil. This system features a transmitter loop to produce a primary magnetic field that will induce eddy current in conductive materials. These eddy currents will generate a secondary magnetic field that will be measured with the receiver loop. This system measures the in-phase and the out-of-phase components of the secondary magnetic field.
The length between receiver and transmitter loops range between 20 m and 400 m for standard applications. This system allows to work with 10 frequency ranging from 110 Hz to 56 kHz. The depth of penetration depends on the spacing and on the frequency. It is usually considered as of the order of half the spacing. A profiling can be performed by moving both the transmitter and the receiver to the next station.
Traditional HLEM slingram systems only measure the vertical component of the magnetic field (Hz). The Secondary/Primary magnetic field ratio being linked to the soil conductivity, they allow to locate conductive structures intersecting a profile. The 3 components measured by the PROMIS system permits to give an information on the direction (strike) of the structure (because the magnetic field remains perpendicular to the eddy current directions).
With the Promis system, the productivity is increased by an automatic processing (measurement automatically carried out for the set of frequencies, without required communication between the two operators). Two leds indicate when the transmitter has to move to the next station. Two inclinometers correct for deviations from horizontal position and a GPS unit can be connected. The selection of the frequencies and the stacking parameters is made at the beginning of the survey for optimizing the field work.
The data can be transferred, edited, filtered, plotted and exported with the EMSYS software provided with the instrument.
Softwares
Applications
Water ressources
- Locate conductive fault in fractured acquifere
- Assess water table characteristics
- Characterize salt water wedge extension in groundwater
Environment
- Monitor pollution
- Detect leaks and monitor degradation in waste disposal
- Locate and image buried structures
Natural hazard
- Detect and characterize cavities
- Assess landslide extension and volume
- Detect and locate clayey layers for geotechnical application
Mineral exploration
Characteristics
Transmitter | |
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Magnetic moment - Loop 75cm/130cm | 360/720 Am2 @ 110 Hz |
320/740 Am2 @ 220 Hz | |
280/560 Am2 @ 440 Hz | |
235/470 Am2 @ 880 Hz | |
220/440 Am2 @ 1 760 Hz | |
160/320 Am2 @ 3 520 Hz | |
110/220 Am2 @ 7 040 Hz | |
60/120 Am2 @ 14 080 Hz | |
30/60 Am2 @ 28 160 Hz | |
15/30 Am2 @ 56 320 Hz | |
Loop diameter | 75 cm. Optional loop 130 cm for doubling the magnetic moment. |
Inclination | 2 inclinometers for horizontal position |
Indicators | Two LEDs (green and red) indicating start/end of reading |
Receiver | |
---|---|
Channels | 3 (Hx,Hy,Hz) channels (on demand) |
Dynamic range | 24 bits |
Resolution | 0.01% of the primary field. |
GPS | GPS input for coordinates |
Readings | in-phase and out-of-phase parts of the three magnetic components Hx, Hy,Hz, standard deviation, tilt angles of transmitter & receiver, battery levels, temperature, GPS data |
Noise Rejection | 50/60 Hz notch filters and overload detection |
Storage | 20000 readings capacity |
Dimensions | |
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Transmitter ( L x W x H ) | 30x20x20 cm |
Receiver ( L x W x H ) | 30x15x20 cm |
Transmitter Weight | 9.8 Kg (5.8 Kg on backpack) |
Receiver Weight | 5.0 Kg |
Operating Temp. | -20 to +70°C |