The EM63 Metal Detector advances the application of time domain electromagnetic (TDEM) methods to the detection of unexploded ordnance. Measurement of the full transient electromagnetic response offers improved detection capability and information on target characteristics.

Comparable to the EM-61 Mk. 2, the EM-63 generates a pulse primary magnetic field which induces eddy currents in nearby metallic objects. The decay rate of these eddy currents with time generates a secondary magnetic field with a specific rate of decay that is determined uniquely by the character - the size, shape, orientation and metal composition - of the object itself.

Measurement of the secondary magnetic field decay (the transient response), therefore, will provide important information toward: a more complete characterisation and classification of the target; identification and rejection of the characteristic response from certain geologic materials (e.g. magnetite); and consequently, a reduction in target selection error ( the "false positive rate").

The EM-63 accurately measures the complete transient response over a wide dynamic range of time: measurements are recorded at 26 geometrically spaced gates, covering a time range from 180 µs to 25ms. Data acquisition is supported by the PRO4000 field computer, with expanded 16 MB data storage capacity, which is able to simultaneously receive GPS data for location control.

26 time gates of secondary response in mV
covering range from 180µs to 25 ms

a) Main: Air-cored coil, 0.5 x 0.5 m in size, coincident with EM source
b) Focusing: Air-cored coil, 0.5 x 0.5 m in size, 60 cm above main coil