FGT High Sensitivity Focused Gamma (182°C)
FGT
Ruggedized, High Sensitivity Focused Gamma Tool (1.36” OD)
The FGT High Sensitivity Gamma Tool is the next generation “shielded” gamma ideal for Azimuthal Geosteering applications. The FGT offers a higher temperature rating (182°C), 25% higher vibration (25 GRMS), greater sensitivity and greater front-to-back count ratio than competing tools. The FGT is a complete electrical and mechanical redesign of our industry standard DGA-C.
The FGT contains a “window” that is machined out of Tungsten material that surrounds the crystal and phototube. Gamma rays emitting from the formation can enter through this window unattenuated, to be detected and counted. Compared to other focused gamma tools, the FGT’s larger window increases detection sensitivity and improves visibility in low gamma activity zones. When aligned with the tool face or other physical reference, the FGT indicates the direction from which gamma ray energies originate.
Electronics
The FGT contains CBG’s new patent pending electronics designs. Encapsulated and cushioned within pre-molded high-temperature silicone pads, the printed circuit boards are protected from extreme shock and vibration. A new and innovative technique for providing electronics temperature compensation ensures a more stable output signal through the full range of operating temperatures. A burst filter has been added to reduce spurious counts that can result from excessive shock and vibration, as well as external transient noise.
Mechanical
The FGT has been completely redesigned without changing the overall mechanical dimensions of the DGA-C. Included is a new patent pending approach to mounting the crystal and phototube for improved shock and vibration performance. No longer exposed to external noise or physical damage, the circuit boards and thru-wires are enclosed beneath metal covers. All load bearing screws have been removed for enhanced reliability.
FGT
Ruggedized, High Sensitivity Focused Gamma Tool (1.36” OD)
The FGT High Sensitivity Gamma Tool is the next generation “shielded” gamma ideal for Azimuthal Geosteering applications. The FGT offers a higher temperature rating (182°C), 25% higher vibration (25 GRMS), greater sensitivity and greater front-to-back count ratio than competing tools. The FGT is a complete electrical and mechanical redesign of our industry standard DGA-C.
The FGT contains a “window” that is machined out of Tungsten material that surrounds the crystal and phototube. Gamma rays emitting from the formation can enter through this window unattenuated, to be detected and counted. Compared to other focused gamma tools, the FGT’s larger window increases detection sensitivity and improves visibility in low gamma activity zones. When aligned with the tool face or other physical reference, the FGT indicates the direction from which gamma ray energies originate.
Electronics
The FGT contains CBG’s new patent pending electronics designs. Encapsulated and cushioned within pre-molded high-temperature silicone pads, the printed circuit boards are protected from extreme shock and vibration. A new and innovative technique for providing electronics temperature compensation ensures a more stable output signal through the full range of operating temperatures. A burst filter has been added to reduce spurious counts that can result from excessive shock and vibration, as well as external transient noise.
Mechanical
The FGT has been completely redesigned without changing the overall mechanical dimensions of the DGA-C. Included is a new patent pending approach to mounting the crystal and phototube for improved shock and vibration performance. No longer exposed to external noise or physical damage, the circuit boards and thru-wires are enclosed beneath metal covers. All load bearing screws have been removed for enhanced reliability.
FGT Specifications
P/N 202-200-000
| Detector | Scintillator Crystal | Sodium Iodide, Na(TI) |
|---|---|---|
| Photomultiplier | R3991A (Hamamatsu) | |
| Mechanical | Diameter (OD) | 1.36” |
| Length (make-up) | 13.6” | |
| Weight | 3.2 lbs | |
| End Connectors | Micro-D Subminiature, 15-Pin | |
| Material | Aluminum Alloy (chassis), Tungsten (shield) | |
| Performance | Sensitivity | 0.52* CPS/API |
| Front/Back Count Ratio (using source at 6”) | 17.5 using Barium-133 3.0 using Cesium-137 |
|
| Accuracy | +/- 5% to 150°C +/- 10% to 182°C |
|
| Environmental | Operating Temperature | -18°C to 182°C |
| Survival Temperature | -40°C to 200°C | |
| Heat/Cool Rate, Max. | 2.8°C (5°F) per minute | |
| Vibration (3 axis) 50-1000Hz, Random | 35G (25G RMS) | |
| Shock (3 axis) | 1000G, 0.5ms, half-sine | |
| Burst Filter | Reduces spurious counts due to extreme shock/vibration and external system electronic noise. | |
| Power Requirements | DC Input Voltage | 10v – 50v, 60v Max. |
| Tool Current | 8-11 mA | |
| Output Signal | Negative Pulse | +5V to GND, 5 uSec width |
* Counts are collected with gamma tool mounted within a standard BeCu pressure barrel, (OD 1.875″, ID 1.500″). API Calibration performed with AEA Technology, QSA Inc., KUTh Field Verifier #188074, S/N 255 Radionuclides: K-40(11.7%), U-238(90 ppm), Th-232(40 ppm).