Radiometric Surveying is commonly used in mineral exploration for geologic mapping, uranium detection and delineation of various intrusives. The objective to conducting radiometric surveys via airborne spectrometer is to determine and map natural radioactive emanations, called gamma rays, from rocks and soils. All detectable gamma radiation from earth materials come from the natural decay products of only three elements at the surface ground. They are uranium (U), thorium (Th), and potassium (K). In order to acquire and process data for viable and useful data for geological interpretation, there are several calibrations that have to be considered.

Learning Objectives

After completing this module, participants will understand the four principal calibrations for an airborne spectrometer:

  • High altitude test flights to determine the cosmic background,
  • Radioactive pads to determine the stripping coefficients,
  • Range flights to determine the attenuation and sensitivity coefficients and
  • Radon background calibration flights to determine the radon coefficients via the upward detector or spectral ratio methods.