Wide Bandwidth Digital Receiver: The CDR2 receiver samples at 4.0 usec with a huge dynamic range of 60 nV to 1V (150 dB, 25 bits) which means it will not overload in normal surveys.
Fast Reading Times: The CDR2 receiver can produce quality data in reasonable reading times even for the very long time bases.
SQUID Sensor Option: The coil sensor can be replaced by the CSIRO HTS-SQUID sensor, which measures the magnetic field. This is useful for long time bases where the dB/dt signal may be small, but the B signal is still large (high conductance or deep soundings).
High Power: The CHT3 4.8 kWatt transmitter can deliver 20 Amps at 240 Volts for very large loops, and can deliver 30 Amps at 160V in smaller loops.
Precise Current Ramps: Precisely- controlled linear ramps of fixed duration allow for proper comparisons to be made between data from different loop sizes, and also allows for an accurate step response transformation.
Long Time Base (Low Frequency): A new long time base of 150 msec (1.67 Hz) ensures that very long time constant conductors can be seen in complicated environments.
Step Response: A new step response transformation allows even longer time-constant conductors to be seen by reproducing the response that would be seen in a direct measurement of the late step response. Our controlled linear ramps and our standard Primary Pulse (PP) measurement on the ramp are necessary for this calculation.
Fast Ramp Option: A new "fast ramp" option duplicates the response seen from other pulse-type systems by shutting off the current as quickly as possible.
True Digital Receiver: The Crone receiver is a true digital receiver in that the input is immediately digitized before stacking and binning. This produces the following feature (programmable gate positions).
Programmable Gate Positions: There is complete freedom of channel (or gate) positions and widths, which can be programmed in the field. There are also numerous built-in tables.
Full Sampling: The entire ramp and off-time can be sampled with contiguous channels if desired in a single sweep.
Current Ramp always Sampled: A Primary Pulse (PP) measurement is always made on the current ramp, which is of great help to ensure proper polarities, and also is crucial for the step response transformation.
High Quality LCD Display: The 256 x 128 pixel LCD on the receiver allows for accurate plots of decay curves and line or borehole profiles on the receiver, and is of great assistance to the operator to monitor noise and anomaly build-up.
No Data Reduction: There is no data reduction for surface surveys and Z-component borehole surveys, so that what is seen on the receiver is what will be seen in the final plots. For 3-D borehole surveys, there is only the correction applied to the direction of the X and Y components to aid interpretation. Gain controls are automatic, so that the output is always in nanoTeslas/sec (= nV/m^2).
Slim-line Probes: A 32 mm probe diameter ensures that virtually all holes can be surveyed with 3-component measurements.
Oriented X and Y Components: X-Y orientation tools accurately orient the X and Y components either with tilt sensors or with 3-axis magnetometers with 3-axis accelerometers. This helps tremendously with giving direction to off-hole conductors and to the centre of in-hole conductors.
Reliable, Durable and Portable Equipment: The PEM system has been in use since the early 1970's under temperature extremes of -40°C to +50°C, in desert, jungle, arctic, mountainous, and underground mining conditions.
