Measured Quantity

Four channels of secondary response in mV

EM Source

Air-cored coil, 1 x 0.5m size.

Current Waveform

Unipolar rectangular current with 25% duty cycle.

EM Sensors

Bottom coil: Air-cored coil, 1 x 0.5 m in size, coincident with EM source.

Top coil: Air-cored coil, 1 x 0.5 m in size 30 cm above main coil

Maximum Output

10 000 mV

Dynamic Range

18 bits

Time Gates

Four gates of bottom coil response only, centered at 261, 376, 527 and 727 µs; or, three gates of bottom coil response at 261, 376 and527 µs, with one gate of top coil response at 527 us after T/O time.

System Controller

Archerfield computer with 486 AMD processor; 16-line LCD display with 24 characters per line.

Acquisition Speed

Up to 16 records (4 time gates per record) per second

Data Storage

512MB internal disk storage :pc card compatible

Power Supply

12 V rechargeable batteries for 4 h continuous operation.