NORM measurements at Kalloni and Gera Gulfs, Lesvos Island, Greece

Natural radioactivity measurements were held in the beach sands of two main gulfs (Gera, Kalloni) Lesvos Island, Greece. These host thermal springs and are preferred tourist destinations throughout year. Dose rates concentrations natural (232Th series, 226Ra 40K) 137Cs measured in-situ laboratory by means gamma ray spectroscopy. Ten sand samples collected from each gulf. The measurement dose rate determination was achieved via a portable NaI scintillation detector (SpriID). activity concentration calculations realized laboratory, with use high purity germanium detector, then they also used to estimate rates. estimated compared verify different approaches. highest values (activity rates) found at beaches Kalloni Gulf those Gera Gulf, which may be attributed granulometry.