Calibration of germanium detectors for applications of radiometric methods in South Africa.

Abstract

AII materials that are radioactive emit characteristic gamma-radiation. Natural radioactivity can be used in heavy minerals exploration and processing, as well as in understanding sediment transport. processes in coastal zones [Dem97][Dem98]. Differences in radionuclide concentrations between minerals, allows the mineral species to be identified and quantified by the activity concentrations of a011, 23216 and 238U using a technique called radiometric fingerprinting [Dem97]. A" important tool to determine sediment transport rates along the coastline is by the MEDUSA technology developed and tested at the Kernfysisch Versneller Instituut (KVI) [Dem98]. The data from the MEDUSA (Multi-Element Detector system for IJnderwater Sediment Activity) system needs to be calibrated first in the laboratory before field measurements can be converted to useful data. The National Accelerator Centre (NAC) is setting up a radiometric laboratory to do this by means of a high-resolution germanium detector used under low-background conditions and constant geometry.