ALLTEM Multi-Axis Electromagnetic Induction System Demonstration and Validation
Cost and performance rept.
ENVIRONMENTAL SECURITY TECHNOLOGY CERTIFICATION PROGRAM OFFICE (DOD) ARLINGTON VA
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Unexploded ordnance UXO is one of the most pressing problems facing the U.S. Department of Defense DoD and other government agencies that have lands that were once used for military training and are now closed or closing and being transferred to civilian or non-DoD government use. Cleanup of all UXO-contaminated lands using existing methods would be prohibitively expensive, so a great deal of effort is being directed to finding better ways to detect, locate and identify buried UXO. It is not sufficient to merely detect buried metal objects because many of these objects are not UXO and pose no hazards. In many cases of range cleanup, 70 or more of the cost consists of locating and removing harmless metal including soda cans, broken parts from agricultural equipment, and fragments of ordnance that exploded as designed. Among the primary geophysical methods for detection and classification are various time and frequency domain electromagnetic induction EMI systems and magnetometers. This project follows Strategic Environmental Research and Development Program SERDP Project MM-1328. In that project one prototype magnetic system, the Tensor Magnetic Gradiometer System TMGS and two prototype EMI instruments, the Very Early Time-domain ElectroMagnetic VETEM system and the High Frequency Sounder, were evaluated. Subsequent to the evaluations, it was decided that a new multi-axis EMI system should be designed, built, and tested. Specifically, we recommended that we should build a multiple component, On-Time Time-Domain Electromagnetic system ALLTEM using a triangle current wave excitation and analyze the data by time-domain methods. This system is able to record at much later times the earth s electrical conductivity response, which has decayed to essentially zero.
- Electricity and Magnetism