Radon Exhalation Rate, Radioactivity Content, and Mineralogy Assessment of Significant Historical and Artistic Interest Construction Materials

In this paper, an investigation focused on assessing the radon exhalation, the natural radioactivity level, and the mineralogy of natural stones of particular historical–artistic interest employed as building materials was carried out. The Closed Chamber Method (CCM) with the Durridge Rad7 apparatus for short-lived radon progeny alpha spectrometry and High Purity Germanium (HPGe) gamma spectrometry were used to determine the radon exhalation rate and specific activities of 226Ra, 232Th, and 40K, respectively. Furthermore, several indices were evaluated to determine the radiological risk due to radiation exposure from the investigated natural stones, i.e., the absorbed gamma dose rate (D), the activity concentration index (ACI), and the alpha index (Iα). Finally, X-ray diffraction (XRD) and Micro-Raman Scattering (MRS) investigations were performed to correlate the chemical composition and mineralogical characteristics of natural stones with the radon exhalation rate and the natural radioactivity content. It is worth noting that the findings from this study can be used to guide future research into the background levels of radioactivity in stones used as construction materials.