Measuring the conductivity profile of trepanned graphite samples using electromagnetic induction tomography

This paper discusses the use of Electromagnetic Induction Tomography (EMT) to measure the impedance of cylindrical graphite samples and to reconstruct the axial electrical conductivity profiles. The measurements are taken as the samples pass through a circular array of eight coils, operating with an excitation frequency of 40 kHz. The conductivities of these samples are then separately measured using a four point probe. A set of reference samples was used to compile a data set, which, by comparing the results, allowed a relationship between the measurements of mutual inductance and the absolute conductivity of the samples to be determined.