Methodology for electric potential sensor noise measurement in salt water

Currently, there is not a known standard that exists for comparing electric potential sensors in salt water. This paper is a study for a methodology to produce repeatable noise measurements for salt water electric potential sensor development. By creating a baseline for each subsystem, a model for overall background noise measurement can be made. This allows for tracking where the dominant noise is added into the overall measuring system. This methodology also allows for variation in sensor creation, amplifier design, and data acquisition system selection to be compared with consistency between datasets. To validate the methodology, a study on a Texas Instruments instrumentation amplifier used as a preamplifier to the electrical potential sensor is performed and shown. The electric potential sensor probe used is comprised of three orthogonal pairs of silver silver chloride (Ag/AgCl) electrodes. Two electric potential sensor probes are designed and tested; one is a three inch diameter spherical probe with cylindrical electrodes and the other is a 3 inch diameter spherical probe with disc electrodes. Both have preamplifier inside the sphere and having the preamplifier contained inside the probe is to limit the noise occurred on the input to the preamplifier. The study is performed and the best sensor option for lowest noise floor is shown.