The AC-23-DH sensor package is a triaxial accelerometer designed for borehole applications regarding Strong Motion earthquake survey and monitoring.

The AC-2x-DH sensors are servo-accelerometers based on a standard exploration geophone mass-spring system with electronic feedback. This type of sensor gives a very good stability versus temperature or aging because of the very simple principle.
The sensor does not require maintenance and has very low aging drift. With the help of the TEST LINE the sensor can be easily, completely tested.

The family of AC-2x-DH accelerometer is directly compatible with the GeoSIG recorders.
The downhole casing contains the entire sensor system. The sensor is connected through Overvoltage Protection stage to the recorder at the surface with a cable.
Using inclinometer tubes and the provided guiding wheels, the sensor can be oriented before insertion in the tube.