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| Measured
parameters |
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Water
content and mean pore size of layers at
depth
Aquifer parameter evaluation |
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| Technical
specifications |
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DC/DC
CONVERTER
- Power supply: two 12 V batteries (60 Ah
each)
- 6 to 8 hour reading autonomy
- Capacitance: 0.1 F
- Outputs: ± 400 V DC ; 0.5 A
TRANSMITTER SPECIFICATIONS
- Supplied by DC/DC converter
- Frequency range: 0.8 to 3 kHz
- Maximum outputs: 3000 V, 300 A
- Pulse amplitude and duration: programmable
- Pulse moment: 100 to 9000 A.ms (for the
standard 40 ms pulse duration)
- Loop tuning capacitance: 18 to 60 µF
RECEIVER SPECIFICATIONS
- Band pass filter width: 100 Hz
- Amplification gain: 100 to 20000
- Programmable gain: 10^4 to 10^6
- Noise: less than 10 nV / sqrt(Hz)
- A/D converter: 14 bits
- Sampling frequency: four times the Larmor
frequency
- Calibration procedure for phase reference
TRANSMITTING / RECEIVING LOOP
- Loop wire: three reels of 100 m long 10
mm2 wire
- Loop impedance: 0.5 ohm ; 0.6 mH
PC COMPUTER
- Control of the whole system: converter,
transmitter, receiver
- Data processing: DFT, stacking
- Data storage
- Data interpretation: 1D inversion
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 NUMIS, Proton magnetic resonance system
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The
The original direct groundwater finder geophysical instrument
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High output power
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High receiver sensitivity
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PC control
The NUMIS system allows the direct detection of groundwater through measurements of the relaxation magnetic field produced by hydrogen protons
from groundwater after they were energized by a current into a loop laid on the ground.
• Depth of investigation: down to 100 m
• Output pulses: 2.5 to 250 A intensity (up to 3000 V), 0.8 to 3.0 kHz frequency, 40 ms standard duration.
• Transmitting/receiving loop: standard 300 m length for 100 m diameter circular loop, 75 m side
square loop or 37.5 side eight-shaped square loop ; other dimensions on request.
• One phase for lower output power
• Equipment control and data interpretation by PC
Working in California with the NUMIS system
NUMIS is a Proton Magnetic Resonance (PMR) system designed for the direct detection of groundwater down to 100 m depth.
NUMIS equipment consists of:
• a converter unit powered by two 12 V batteries
• a transmitter-receiver unit for pulse generation and signal measurement
• a wire loop used both as a transmitting and a receiving antenna
• a PC computer for the control of the whole system and for data processing and interpretation.
PMR for groundwater:
The field application use of the Proton Magnetic Resonance (PMR) method is based on a well established theory.
PMR is the only non-invasive method which directly studies groundwater reservoirs from surface measurements
Principle of the method:
Hydrogen atoms of water molecules are energized by pulses of alternative current at the proper frequency (Larmor frequency), transmitted into a loop laid on the ground.
The magnetic field they produce in return is measured and analyzed for various energizing pulse moments (ntensity x duration).
Heavy Duty Construction:
Very high quality connectors, and heavy duty industrial components are used throughout. The VIP 10000
is shock resistant and weatherproof, for a higher reliability.
Information Obtained:
The interpretation of measurements permits to estimate the water content and the mean pore size of each layer at depth.
These parameters are useful to determine the prospects of a groundwater reservoir before drilling
PMR Field Measurements
The transmitting antenna consists of a 100 m diameter loop laid on the ground, allowing a depth of investigation of the order of 100 m.
The Larmor frequency varies between 0.8 and 3.0 kHz depending on the amplitude of the local Earth's magnetic field.
The energizing current in the loop will reach intensities of 200-300 A during pulses of a few tens milliseconds.
The relaxation field of the protons is measured in the same loop, after the energizing current is turned off. The
voltage measured in the loop is of the order of a few tens to a few thousands nanovolts. Stacking is used to enhance
the signal. Taking the readings corresponding to a complete PMR sounding with a full set of pulse moments, usually
takes less than one hour per station.
Basics of proton magnetic resonance sounding
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THE PROTON MAGNETIC RESONANCE METHOD FOR GROUNDWATER INVESTIGATIONS
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Download Tutorial File - (PDF) ... 
View a tutorial file (Acrobat format) for more information on the magnetic resonance method. (To download, right click on the link and select the save option).
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Copyright
© 1998 IRIS Instruments
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Company Profile