• ASSAY of K, U and Th in various geometries (infinite area, intrusions in outcrops, boreholes, caves
• Combination of K, U, Th assay with surface contamination measurement (Cs-137 or other nuclides in Bq/m2 – Chernobyl, Fukushima)
• Determination of ratio between U and Ra
• Targeting of Radioactive Sources
• Nuclide Identification including Categories and Intensities
• Activity evaluation in various units (Bq, Ci, volume, mass or area activities)
• Long term monitoring in predefined tasks for permanent surveillance
• Building Materials Certification
• Activity Index, Gamma Index, Radon Index


The new GT-40 series represents a major step forward in portable gamma-ray spectrometry for geological, geophysical and environmental surveying, prospecting and investigations. The compact unit with integrated GPS provides the user accurate and reliable results in real time.

The GT-40 and GT-40 S are identical except for the type of detector, see above.

The 3” x 3” NaI(Tl) detector has high sensitivity and good resolution; it can be used for a variety of field applications.

The GT-40 S model with a 2” x 2” BGO detector and lead shielding should be used for focused measurement of cores or for stratigraphic measurements.

Using internal constants based on IAEA traceable calibration pads, the GT-40 can compute precise rock concentration of K (%), U and Th (ppm). Results are displayed immediately after end of measurements. They will be stored in the instrument and/or sent to appropriate external devices via Bluetooth or Wi-Fi.

A high sensitivity built-in GPS receiver can automatically record the geographical position and store it with each measurement. Measurements can be stamped with voice notes. Stored voice messages can be played back through the built in speaker. Survey data, including position, dose rate, total gamma and assay data can be collected point-by-point or automatically while walking or driving.

Examples of GT-40 applications:

  • Exploration for Uranium, Thorium and other associated metals such as REEs
  • Geophysical research
  • Geological mapping
  • Baseline surveying
  • Core logging
  • High sensitivity lab measurements
  • Base station monitoring
  • Classification of building materials
  • Land use radon risk assessment
  • Environmental monitoring
  • Surface contamination surveys
  • Monitoring waste disposal sites



GT-40 Accessories 1
GT-40 Multi-Purpose Gamma-Ray Analyzer Brochure 1
GT-40 Multi-Purpose Gamma-Ray Analyzer Manual
GT-40 Presentation