About Us
Contact Us

Rotunda Scientific Technologies
Call us today!
Gamma Spectrometry
GMS311 Spectral Core Gamma Logger Spectrometer
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 as well as 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, which are 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 for power 1) on/off, 2) backlight, 3 & 4) up/down and 5 & 6) accept/decline. In addition to the large buttons the easily readable display has a bright backlight to allow operation in bright sun light or lighting conditions. On time for the backlight 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 allow you to focus on your job and not be waiting for the instrument to do its job. Sampling time is selectable via the onboard menu. Data is stored in the instrument until you have time to return to your computer to extract the measurements via the weatherproofed enclosed USB connector. Behind the weatherproof enclosure is also the power recharging jack.

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). 
GMS311 with rugged carrying case and included accessories
GMS311 USB & power jack protective cover (closed & open) 
Battery access is below the protective cover
GMS311 Spectral Gamma Core Logger
Hand-held Gamma Spectrometer
  • 51 x 51mm (2" x 2" NaI Detector)
  • 6 ROIs & 1 Total Integral
  • 3 ROIs preset, but are user settable
  • Simple menu / 6 key operation
  • Designed for rugged environments
  • USB data output, cable included
  • Rechargeable batteries, included
GMS Spectral Gamma Logger Specifications
Display                         128 x 64 pixel Transflective LCD
                                      with white LED backlight
User Controls              6 button operation:
                                      Power ON / OFF
                                      Back / No
                                      Accept / Yes
User Connections       Charger Input
                                      USB Type B for connection to a PC
Detector                        Large 51 x 51 mm (2" x 2") Nal(TI)
Energy Range              90 to 2,100 keV
Power                           2 NiMH 4000 mAh 'C' size batteries
                                      ~12 hrs. operation at 20°C
                                      Full charge in ~10 hours
Charger                        Input Supply 110 to 240 V AC,                                                 supplied with worldwide connectors
Temperature                Operating Range: -10°C to 50°C
                                                                  (14°F to 122°F)
                                      Slowed Display   -20°C to 60°C
                                      at lower temps:    (-4°F to 140°F)
IP Rating                      IP 54
External Dimensions   330L x 150H x 90W mm 
                                      (13"L X 5.9"H X 3.5"W)
Weight                          1.9 kg (4.2 lbs)
Transport Case            (Transport case details may vary)
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
Serving the External Dosimetry, Radiation Detection, and Spectroscopy communities since 2012.
Designed by Rotunda Scientific Technologies™ LLC © 2012-2018