Radon concentrations and absorbed dose measurements in a Pleistocenic cave

Radon concentration measurements were carried out using solid-state nuclear track-etch detectors (SSNTDs) type CA 80-15 cellulose nitrate films, in a Pleistocenic cave at Petralona, in Halkidiki, Northern Greece, at 55 km from the city of Thessaloniki. Radon levels as high as 88 kBq^.m^-3 (2.38 nCi^.l^-1) have been recorded inside the cave equivalent to 11.90 WL in terms of occupational exposure to radon and its decay products. Absorbed dose rates were performed using TL dosimeters, type TLD-200 (CaF₂-Dy) in a continuous monitoring program (integrated measurements). Dose rate levels as high as 110 nGy^.h^-1 were recorded inside the cave. In interpreting the high levels of radiation doses, radioactivity measurements regarding the naturally occurring ²³⁸U, ²³²Th and ⁴⁰K radionuclides were carried out in various speleothems found at different sites in the cave.