Electromagnetic Induction (Emi) Coil Sensitivity Maps For Evaluating Coil Designs And Configurations Used In The Geophysical Detection Of Unexploded Ordnance (Uxo)

This paper summarizes efforts to develop and test a software tool for evaluating electromagnetic transmitter coil designs and configurations used in the geophysical detection of unexploded ordnance (UXO). In particular, we are interested in evaluating the detection and discrimination potential of Wide-Area Transmitter and Multi-Transmitter (WAT-MT) sensor systems. The effort is directed toward developing a better understanding of the capabilities and limitations of WAT-MT sensor systems. A Matlab computer code has been developed that maps sensor response to a standardized infinitesimal object in a static field. These plots take in full account of both the transmitter and receiver coil shapes with no explicit consideration of target characteristics. The software allows the user to obtain sensitivity as well as streamline plots. Streamline plots are preferred over sensitivity plots when one is interested in visualizing the direction of the magnetic field due to the transmitter and/or receiver coil. A combination of streamline and sensitivity plots provides good insights into the overall capabilities of a particular coil configuration and also allows one to objectively compare competing designs. Measurements with the Geonics Ltd EM-61 and EM-63 will be compared with sensitivity plots in order to validate the WAT-MT software tool.