The radiometric, or gamma-ray spectrometric method is a geophysical process used to estimate concentrations of the radioelements potassium, uranium and thorium by measuring the gamma-rays which the radioactive isotopes of these elements emit during radioactive decay. Airborne gamma-ray spectrometric surveys estimate the concentrations of the radioelements at the Earth’s surface by measuring the gamma radiation above the ground from low-flying aircraft or helicopters. (AUS source). EDCON-PRJ typically offers radiometric acquisition service along with magnetic survey acquisition.
Our acquisition instrumentation is the AGRS System. The AGRS System consists of four independently-processed detectors for a total of 16.8 liters of downward –looking NaI crystals. The 512 channel processors provide high-resolution and excellent signal to noise ratios throughout the gamma ray spectrum. We offer airborne radiometric surveys utilizing both helicopters and fixed-wing aircraft. Pico Envirotec’s Advanced Geophysical Information System enables our operators to monitor individual detector performance in real time. The 512-channel resolution of the AGRS along with the use of Geosoft Praga 4 processing software allows for removal of radon effects through 214 Pb photopeaks and eliminates the need for an upward-looking crystal.
Raw data is low resolution and shows banding effects due to daily differences in temperature, humidity, radon, and soil moisture. Our primary processing methods include removal of radon and cosmic background, correcting for temperature and humidity, and normalizing to Thorium. Our Advanced Processing techniques include isolating the Potassium, Uranium, and Thorium (KUTh) channels from the Total Count spectrum. The result is a much higher-resolution image than the standard Total Count Map. This data is then used to generate individual Potassium, Uranium and Thorium Concentrations.
For more information please contact us, or download our Radiometrics brochure
We recommend reading International Atomic Energy Agency, “Radioelement Mapping” for more information about hydrocarbon microseepages.
Suggested reading :
Saunders, D.F., Burson, K.R. Branch, J.F., Thompson, C.K., “Relation of Thorium-normalized Surface and Aerial Radiometric Data to Subsurface Petroleum Accumulations” Geophysics Vol. 58 No. 10 Oct. 1993.