Patent ID: 8310243

Claim:
An LEIS method for detecting coating defects in an underground structure buried in soil, comprising: placing a bi-electrode probe in the soil above the structure, the bi-electrode probe having two probe tubes, each tube having an in-soil end and an above-ground end, each probe tube having a probe electrode extending from the in-soil end; wherein the probe tubes are arranged such that the probe electrodes are vertically spaced when the bi-electrode probe is in place, each probe electrode having a contact end for contacting the soil above the structure; wherein at least one of the probe electrodes is moveable with respect to the other such that the vertical distance between the probe electrodes is variable; applying a sinusoidal voltage to the structure over a range of frequencies; receiving a response signal from each probe electrode; processing each response signal to obtain calculated data; and analyzing the calculated data to detect the presence of a coating defect.