Gamma radiation measurements of naturally radioactive samples at INFN Bari laboratory

Abstract

High-resolution gamma-ray spectrometry is a widely used non-destructive measurement technique for the assessment of gamma-ray emitting radionuclides present in environmental samples. These measurements allow the evaluation of the radiological risk to the human beings and environment. The gamma radiation measurements laboratory, in the Physics Department of the University of Bari in collaboration with the Italian Institute for Nuclear Physics (INFN), is active since 2008. The laboratory is equipped with a an Ortec n-type coaxial high purity germanium (HPGe) detector.In this paper, an overview of the ongoing activities on gamma radiation measurements in our laboratory, will be given. These measurements are based on the precise knowledge of the absolute full energy-peak efficiency (FEPE) of the HPGe detector. The FEPE, evaluated using point and volume calibrated sources, will be presented and will be compared with the efficiency obtained using a dedicated software for gamma spectrometry (GammaVision and ANGLE). Furthermore, we present the efficiency calculated via Monte Carlo (GEANT4) simulation. We also describe a case study of gamma measurements application to the dating technique based on the Thermoluminescence (TL). A preliminary study on the evaluation of the gamma annual dose absorbed by TL dating samples, using GEANT4, will be described.