GMS312 Rolling API Core Gamma Logger


The GMS312 Core Analyzer is a Rolling Core Gamma Logger designed to detect naturally occurring gamma radiation. Cores from 3.5 in. to 12 in. can be accommodated.

“…on site core analysis allows the operator to make effective, real-time assessments of the well site.”

The GMS312 offers the ability to log elemental concentrations of Uranium, Thorium, and Potassium by means of spectral analysis of gamma emissions from core materials. Data can be displayed in either API units or counts in six user-defined Regions of Interest plus gross gamma count.

There are two measurement modes; Dynamic and Static. In the Dynamic mode, continuous measurements are made whilst the GMS312 is rolled along the core at a preset speed. In the Static mode, the GMS312 is moved to each location and a static measurement is made. In each mode, the depth is displayed.

Survey results are saved to the internal memory of the instrument so that they may be downloaded and analyzed on a PC via the Core Analyzer Application software.

Download the GMS312 Brochure


    • Rolling Spectral Core Gamma Logger
    • API units
    • Plot of Units vs Depth in Dynamic mode
    • Factory preset Regions of Interest: Potassium, Uranium, Thorium & Total Gamma (KeV)
    • 3 additional optional user-defined Regions of Interest
    • Data Logging
    • Background Correction
    • Metric, Imperial or US units
    • Preset rolling speeds in Dynamic mode from 25 to 1000 mm/s (1 to 39.4 inches/s)
    • Preset measurement intervals in Static mode from 25 to 1000 mm (1 to 39.4 inches)
    • Preset sample periods in Static mode from 10 to 900s
    • Handle for comfortable operation




      • 480 x 272 pixel transflective LCD with white LED backlight​

      User Controls

        • Power ON / OFF
        • Backlight
        • Back / No
        • Accept
        • Up / Down
        • Left / Right

        User Connections

          • Charging Input
          • USB type B for connection to a PC


            • 8 GB Internal Memory
            • PC Software Core Analyzer Data Manager included


            • Internal NiMH 7.2 V 6000 mAh battery
            • ~12 hrs. operation at 20°C

          Power Supply

            • Input supply 110 to 240 V ac, supplied with world-wide connectors


            • 72 x 72 mm (2.8" x 2.8") NaI(TI)

          Energy Range

            • 90 keV to 2,700 keV


            • Operating Range -10˚C to 40˚C (14˚F -104˚F)

          IP Rating

            • IP54

          GMS312 Dimensions and Weight

            • 320L x 320H x 150W mm (12.6"L x 12.6"H x 5.9"W)
            •  Case Dimensions
              • 508 x 432 x 229 mm (20 x 17 x 9 in.)
            • Total Weight with GMS312: 16.5 kg (36 lbs)

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