GTEM
from Geonics
The Geonics G-TEM is a complete TEM system offering advanced quality control and analysis features to assist operators obtain reliable near surface resistivity soundings. Designed to be portable and simple to operate, the G-TEM offers an intuitive user interface and menu for implementing central loop soundings, moving receiver and Slingram records.
As standard the G-TEM is supplied with a TEM47 transmitter- suitable for prospection to up to 150m- which is built into the lid of modular briefcase style housing. In instances where large central loop sounding are undertaken the Transmitter (lid) and Receiver (bottom) can be separated and a custom length reference cable employed. The G-TEM receiver is compatible with all TEM transmitters and Receiver coils supplied by Geonics; equally the G-TEM transmitter can be used with the PROTEM.
Through incorporating a Laptop PC into the G-TEM receiver operators can perform all functions on the instrument itself including full infield inversions of sounding curves. Built-in test routines aids validate system setup and noise levels before acquiring data.
The G-TEM data acquisition software centres on a graphical sounding display and geometry window, survey parameters and time gate amplitudes flank the screen.
Product Dimensions
| Physical | Dimensions (L x W x H) | Weight |
|---|---|---|
| GTEM (instrument only) | 40cm x 32cm x 18cm | 13kg |
Technical Specifications
| Display: | 10 inch colour touchscreen LCD. |
|---|---|
| Measurement Quantities: | Rate of decay of magnetic field, in nV/m². |
| Channels: | 1 Channel. |
| Time Gates: | 20 gates covering 2 time decades 30 gates covering 3 time decades, or User-programmable |
| Dynamic Range: | 16 bits minimum. |
| Base Frequency: | 0.3, 0.75, 3, 7.5, 30, 75 and 285 Hz, or 0.25, 0.625, 2.5, 6.25, 25, 62.5 and 237.5 Hz. |
| Integration Time: | 0.5, 1, 2, 4, 8, 15, 30, 60 or 120 s. |
| Data Storage: | 320 GB internal hard drive; memory stick compatible. |
| I/O Ports: | RS-232, USB and RJ45. |
| Synchronization: | Reference cable. |
| Power Source: | -15V rechargeable lithium battery. |
| Number of Records Per Station: | 1, 2, 5, 10, 30, continuous |
| Current Waveform: | Bipolar rectangular current with 50% duty cycle. |
| Base Frequency: | 30, 75, or 285 Hz (power line frequency 60 Hz) 25, 62.5 or 237.5 Hz (power line frequency 50 Hz) |
| Turn-Off Time: | 2.5 μs at 3A into 40 x 40 m loop; faster into smaller loop. |
| Transmitter Loop: | 1 x 1 to 100 x 100 m single turn loop, or 5 x 5 m 8-turn loop. |
| Output Voltage: | 0 to 9 V, continuously adjustable, with internal 15 V battery. |
| Output Current: | 3.5A with internal 15 V battery. |
| Power Source: | Internal 15 V rechargeable lithium battery; optionally, up to four external 12 V batteries. |
| Battery Life: | 8h continuous operation at 2A output. |
Shipping
| Contents | Dimensions (L x W x H) | Weight |
|---|---|---|
|
Case1
GTEM |
66cm x 58cm x 51cm | 48.5kg |
|
Case2
Transmitter cable reel (for 40mx40m loop) |
63cm x 53cm x 57cm | 60kg |
|
Case3
Receiver coil, Q coil. |
66cm x 74cm x 18cm | 22.5kg |
Shipping Notes:
System will be consolidated onto a 12cmx100cmx95cm pallet, total weight 145kg.
Data Sheet
- GTEM Datasheet (PDF)
Literature
- Applications of Transient Electromagnetic Techniques (PDF 5MB)
- Application of simple loop models to the interretation of transient EM surveys in a resistive enviroment (PDF 5MB)
Checklists
- Checklist for Data Storage and Transfer (PDF 249KB)
- Checklist for Field Editing (PDF 244KB)
