NGT-075-B Gamma Tools


Gamma Tools (.075” OD)

Our NGT-075-B gamma tools are the smallest diameter scintillator gamma tools available on the market today. With an outside diameter of only 0.75” they are ideally suited for mounting within the drill-collar wall to make superior directional gamma sensors. We offer two versions of the NGT-075-B with various protection options for the tool and its electronics.

Magnetic materials are kept to an absolute minimum to limit interference with closely mounted magnetometers.

PN 204-200-000_NGT-075-B with MEP-800x503

(w/ Molded Electronics Protection)
P/N 204-200-000

The latest version of the NGT-075-B contains our new Molded Electronics Protection optimized for extreme drilling environments. Pre-molded pads cover and protect the top and bottom of the circuit boards, replacing the traditional protective silicone mixture poured over the boards. This new encapsulation method of the circuit boards improves reliability by dispatching excessive heat and minimizes the impact of shock and vibration to the electronics. The molded pads also improve serviceability by allowing easy removal to provide access to the electronics for inspection and repair.

PN 204-400-000_NGT-075-B with ES_OPEN-800x503
PN 204-400-000_NGT-075-B with ES_CLOSED-800x503

(w/ Encapsulation Sleeve)
P/N 204-400-000

CBG’s Encapsulation Sleeve is offered as an alternative to traditional collar mounting methods that may be less effective at protecting gamma tools in harsh drilling environments. Our molded encapsulation sleeve insulates the entire NGT-075-B tool, including its electronics. It reduces shock and vibration by 50% on the NGT-075-B when mounted in a collar. The pre-molded sleeve consists of two pieces that are approximately 1.0” OD when assembled around the .075” gamma tool. Ribbing on the outside of the sleeve provides gripping and allows for thermal expansion. The inside of the sleeve contains precisely molded impressions of the top and bottom of the circuit boards for electronics protection.

NGT-075-B Specifications

P/N 204-200-000 P/N 204-400-000
Detector  Scintillator Crystal Sodium Iodide, Na(TI) Sodium Iodide, Na(TI)
Photomultiplier R4177A (Hamamatsu) R4177A (Hamamatsu)
Mechanical Diameter (OD) 0.75” 1.003″ (Sleeve)*
Length (make-up) 13.7” 14.215″ (Sleeve)**
Weight 8.4 oz. 8.4 oz.
End Connectors Flying lead (Power, GND, Output) Flying lead (Power, GND, Output)
Material Aluminum Alloy Aluminum Alloy
Performance Sensitivity .76 CPS/API .76 CPS/API
Accuracy +/- 5% to 150°C
+/- 10% to 175°C
+/- 5% to 150°C
+/- 10% to 175°C
Environmental Operating Temperature -18°C to 175°C -18°C to 175°C
Survival Temperature (reduced accuracy) -40°C to 200°C -40°C to 200°C
Heat/Cool Rate, Max. 2.8°C (5°F) per minute 2.8°C (5°F) per minute
Vibration (3 axis) 50-1000Hz, Random 20G (14G RMS) 25G (18G RMS)
Shock (3 axis) 500G, 0.5ms, half-sine 500G, 0.5ms, half-sine
Power Requirements DC Input Voltage 17-48 VDC, 50VDC Max. 17-48 VDC, 50VDC Max.
Tool Current 8-11 mA 8-11 mA
Output Signal Negative Pulse +5V to GND, 5 uSec width +5V to GND, 5 uSec width

* Recommended cavity diameter, 1.0″
** Recommended cavity length, 14.2″

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