Substrate characterization for underwater gamma spectrometry: tank measurement results utilizing efficiencies calculated via Monte-Carlo code

In order to study the sediment contamination, underwater gamma-ray spectrometry measurements performed by the sub-marine detector Canberra HpGe with a relative efficiency of 80% were carried out in an equipped tank at the Ukrainian Hydrometeorological Institute of Kiev. Different substrates, certified sources and experiment geometrical set-up were arranged. Efficiencies were calculated by in situ object counting system (ISOCS) software. ISOCS performance tests using certified sources were carried out by comparing laboratory measurements, and measurement results for mineralogy and density performances are reported.