Quick assessment of radioactivity levels indoor of granite historical buildings of Braga (NW Portugal)

Abstract

Building materials are the main source of radioactivity in buildings. Radioactivity indoors is a source of health risk and it depends on the geometrical characteristics of buildings and materials (mainly the content in K, U, and Th) although other sources of ionizing radiation can be considered (cosmic radiation, subsoil radon flux). We present results of measurements of indoor gamma radiation by field gamma spectrometry in granite buildings of Braga (N Portugal), considering the total dose and estimations of K, U and Th contents, related to materials. Results are analysed in terms of comparison of the different places and measurements indoor and outdoor, regardless of granite type and geometrical features of the built works.