top of page

GR38 & GR25: Natural Gamma Radioactivity

In addition to its primary role as a lithological or clay indicator, a Natural Gamma measurement is frequently used as the basis for establishing correlations between boreholes and to ensure accurate depth matching between different logging runs made in the same borehole. For these reasons, many LIM LOGGING probes provide this measurement as an additional log along with other parameters.

The GR38 & GR25 probes provide a solution for cases where only a basic, total counts natural gamma log is required.

Based on a ø25 x 50 mm NaI(Tl) and ø12.7 x 50 mm NaI(Tl) scintillation crystal detectors coupled to a high-performance photomultiplier tube, the probes boast excellent sensitivity (±1.2 cps / API unit) and provide a high quality final result.

Contact us to get a quote or request more information.

GR38 probe diagram




 Simple but efficient


Technical Specifications

Diameter : 38 mm

Length : 1200 mm

Weight : 3.0 Kg

Max. Temp : 70°C

Max. Pressure : 200 bar


Sensors Parameters

 Detector size : ø25 x 50 mm


Options And Accessories

 Calibration : factory calibration in API units

Capture d’écran 2020-11-02 à 16.53.15.

Borehole Conditions

Dry or fluid-filled borehole

Open or cased borehole

bottom of page