A four terminal measurement system for measuring the dielectric properties of clay at low frequencies

Recently there has been increasing interest in the use of the frequency dependent dielectric properties of clay soils as a potential method of contaminant detection. The study of dielectric properties of contaminated clays at lower frequencies is of particular importance as this has been theoretically argued to be the range in which the interfacial polarisation and double layer polarisation occurs. These are phenomena which provide valuable information on the physical and chemical properties of clays and how these will change in the presence of contaminants. r, dielectric measurements are more difficult to obtain at low frequencies due to a number of phenomena that can cause measurement errors. Four terminal measurement systems are theoretically capable of reducing the error due to the phenomenon of electrode polarisation. A commercial probe that is normally used to measure the biomass of biological suspensions has been tested for its suitability to make dielectric measurements in clays. Preliminary results highlight some of the problems with calibrating such a system for this type of measurement and indicate that the problems of electrode polarisation can still persist.