The molecular-electronic transfer (MET) technology offers an alternative to regular electromechanical devices,
providing high performance seismic data in compact-size, robust, easy-to-install instruments.
The operation principles of the MET instruments are based on charge transfer variations due
to electrolyte motion in the 4-electrode electrochemical cell.
A typical MET transducer cell contains anode and cathode electrodes separated by microporous
dielectric spacers. The cell is filled with a highly concentrated iodine-based electrolytic solution
with a small DC-offset voltage applied between the electrodes.
The physical principles of operation could be understood by analogy to an electronic vacuum tube.
If, by some means, the grid could be made to move in response to an external mechanical acceleration
(say, ground motion), the tube’s current would be changed accordingly.
The signal power would be amplified by many orders of magnitude at the expense of the anode power source.
In a similar manner, an external acceleration along the sensor input axis causes the MET electrolyte to flow,
changing the anode-cathode current. In this system, the electrolyte plays a dual role of the “grid” and
the inertial mass. The resulting power gain eliminates the need for large inertial masses -
the liquid electrolyte is just a few grams.
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