Natural radioactivity level in materials used for medieval vaulting in the territory of the central Balkan region

This work presents the results of an investigation undertaken to determine the level of natural radioactivity in the traditional building materials used for medieval indoor vaulted constructions in the territory of the central Balkan region. Indoor radiation exposure varies appreciably if it comes from the earth building materials, hence the presence of natural radioisotopes of 226Ra, 232Th, and 40K in masonry vaulted constructions was analyzed using gamma ray spectrometry. In addition, the internal health hazard index, the absorbed dose rates and the effective annual doses were calculated. The results were then compared both with the reported data from the previous studies concerning the territory of the Balkan Peninsula, as well as with the worldwide values for the materials of historic buildings. The results obtained from the materials examined in this paper all showed the radioactivity levels below the maximum permitted values. [Projekat Ministarstva nauke Republike Srbije, br. 171007 i br. 43009]