A geothermal pyrolysis system is configured to convert a slurry into a petroleum material. The first electrode is formed on the substrate. The system provides means for monitoring probe position and probe liftoff, means for storing virtual flaw signals and associated locations on a test piece, and means for providing a virtual flaw signal to the NDT instrumentation to simulate the response of the actual probe. 46 mm on X and Y axes can be reduced by at least 20%, in turn improving the repeatability, linearity error and a correlation error associated with the sensor.