Groundwater detection system Numis Lite

magnetic resonance sounding

The Numis lite device is a Magnetic Resonance Sounding (MRS) system for the direct detection of shallow groundwater down to 50 m of depth. This compact MRS equipment features: • a converter/tuning unit powered by two 12 V batteries, • a transmitter-receiver unit for pulse generation and signal measurement, • a wire loop used as a transmitting and a receiving coil, • a PC computer for the control of the whole system, and for data processing and interpretation The MRS method is the only non-invasive method which directly studies groundwater reservoirs from surface measurements: A pulse of current, at a given frequency is transmitted into a loop. The protons of the groundwater are excited. The signal produced during their return to equilibrium is measured with the same loop. To realize a sounding, different pulse moments (A.ms) are injected in the loop, all corresponding to different investigation depths. This measure gives access to the soil water content (%) and is related to the mean pore size (permeability).