The standardisation of airborne gamma-ray surveys in Australia

Abstract

In the last few years, the use of airborne gamma-ray spectrometry for geological mapping and mineral exploration has shown considerable growth. With this growth there has developed an increasing need to standardise the airborne measurements so that they will be independent of survey parameters. This paper describes the various calibration and processing procedures that have to be followed to achieve this goal through the conversion of the airborne measurements to ground concentrations of potassium, uranium and thorium. One of the most critical steps in this process is in the use of airborne calibration ranges whose potassium, uranium and thorium content must be measured at the time of the calibration flights. Two calibration ranges have been set up in South Australia and Queensland. However, these ranges are radioactively inhomogeneous which has made this calibration task more complicated than it otherwise would have been.