: Alpha Geo Science :

INTRODUCTION
The terraTEM has been designed to provide true high speed sampling at 500 KHz using three simultaneous channels for maximum survey efficiency and high resolution. The fast turn-off capacity of the in-built transmitter, combined with high sample densities, provides a new capacity for high-definition images at shallow depth. It provides attractive new options for advanced geotechnical surveys as well as conventional surveys for mineral exploration. The terraTEM has been able to take new technologies and adapt them into the one unit. Innovations include a colour touch screen, high sampling rates and enhancements in the display and interpretation of the data in the field. The unit makes TEM more accessible to Students and Geophysicists by providing an intuitive graphical user interface.

SYSTEM
The terraTEM is a new transient electromagnetic survey system designed and constructed in Australia. It incorporates a 10 Amp transmitter and a true simultaneous 500 kHz 3-component receiver.

The unit is powered by an external 24 V battery pack system allowing 6-8 hours of continuous operation. An inbuilt GPS is mounted on the front panel, allows for location information to be automatically recorded with soundings. All connectors are external to the case allowing easy transportation without having to shutdown between sites. The user interface comprises a 15" colour LCD panel and a touch-screen. Menus are designed to allow intuitive and rapid transition between critical acquisition parameters and data display. Spectral analysis, combined with DSP options, allows the user to monitor and identify local sources of noise; these may be removed ultimately using additional filters specific to local site conditions. A diagnostic menu provides access to a spectrum analyser as well as time-domain views of the input signal for rapid troubleshooting or optimisation of acquisition parameters to ambient site conditions. Data is stored in an expandable 1 GByte solid-state memory. This provides the user with essentially unlimited storage space (up to 500,000 soundings), making the terraTEM system ideal for rapid, high-resolution surveys. System parameters are stored automatically with each sounding for post-survey quality assurance. Data is transferred to a desktop PC by using a standard USB memory flash drive.

The terraTEM is packaged with data reduction and processing software and can generate onsite standard profile and decay plots, apparent conductivity pseudo-sections and contour plan maps. Images can be saved as bitmaps and inserted directly into reports. Synchronisation with an external transmitter is optional.

For high-power applications an optional external transmitter, the terraTX-50, is available. The terraTX-50 delivers up to 50 amps and can be synchronised by either reference cable or GPS timing. The external transmitter option gives you full control over output current and voltage.

	terraTEM	Options
Transmitter Output	10 Amps. (max.)	Enhanced Transmitter
Receivers	1 Channel	3 Channels (simultaneous)
High Resolution Sampling Rates	500 kHz	-
User Selectable Multiple Time Gates	-	Option
Data Visualisation and Processing in field	Standard Software	Enhanced Software
Storage Device - Flash Drive	Standard	-
GPS Receiver - 12 channel	-	Option
Communications - Port for Data Transfer	USB and RS-232 Standard	-
External Synchronisation	-	Option
Continuous Recording (with external GPS Interface)	-	Option
Extra Stacking Options and Gain Functions	10 Selectable Gain Settings from 1 to 8,000	Auto Gain
Vectem 4 Interface Module (down-hole)	-	Option
Dimensions: Console: 530 x 350 x 160 mm. 13 kg Battery Box: 280 x 250 x 180 mm. 12 kg.
Operating Temperature: -10 to 40 degrees C.