GMS311 Spectral Gamma Core Logger

Please request more information if you are interested in this product.


The GMS311 Spectral Gamma Logger (GMS Core) is ideally suited for the user that requires simple, easy operation and rugged reliability. This is especially useful in the geophysical field of well or borehole logging and other industrial applications. The 6 regions of interest (ROI) allow the user to preset specific radionuclides important for your investigative or operational environment. With the GMS311 you don’t need to be a physicist to understand the results, as is common with more complex units that provide spectrum data for radionuclides unimportant to your operation. The GMS Core comes preset with commonly used radionuclides, such as Uranium, Thorium and Potassium. In addition to the 6 ROIs the unit uses an additional region covering the entire energy range for overall gross measurements.​

Operation of the GMS311 is accomplished through the use of the 6 large buttons that are easily operated even while wearing gloves or PPE. The buttons are color coded into function groups:

    • Red - On/Off
    • Yellow - Backlight
    • Blue - Up/Down
    • Green - Accept
    • Red - Decline

In addition to the large buttons the display has a bright backlight to allow operation in bright sun light or lighting conditions. The backlight on/off timer is adjustable via the menu.

With the large 51 x 51 mm (2 x 2 in) NaI detector the GMS311 provides quick isotope detection and identification times to reduce downtime and increase worker efficiency. Sampling time is selectable via the onboard menu. Data is stored in the instrument and the measurements can be extracted to a computer with the weatherproofed enclosed USB connector. Behind the weatherproof enclosure is also the power recharging jack.




    • 128 x 64 pixel transflective LCD screen with white LED backlight

User Controls - 6 Button Operation

    • Power ON / OFF
    • Backlight
    • Back / No
    • Accept / Yes
    • Up
    • Down

User Connections

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


    • Large 51 x 51 mm (2" x 2") Nal(TI)

Energy Range

    • 90 to 2,100 keV


    • 2 NiMH 4000 mAh 'C' size batteries
    • ~12 hrs. operation at 20°C
    • Full charge in ~10 hours


    • Input Supply 110 to 240 V AC, supplied with worldwide connectors


    • Operating Range: -10°C to 50°C (14°F to 122°F)
    • Slowed Display at lower temps: -20°C to 60°C (-4°F to 140°F)

IP Rating

    • IP 54

GMS311 External Dimensions

    • 330L x 150H x 90W mm (13"L X 5.9"H X 3.5"W)


    • 1.9 kg (4.2 lbs)

Transport Case

    • Details may vary

Transport Case Dimensions

    • 500L x 210W x 390H mm (19.7"L x 8.3"H x 15.4"W)

Total Weight

    • 7.5 kg (16.5 lbs) with GMS311 and accessories


Included with Purchase

A rugged case, rechargeable batteries, battery charger, USB cable and PC software are included and complete the GMS311 package making the unit ready to use out of the box (after fully charging the batteries). ​


We Also Recommend