Assessment of natural radioactivity and mass attenuation coefficients of brick and roofing tile used in Turkey

In this study the distribution of natural radionuclides ((226)Ra, (232)Th, (40)K) in brick and roofing tile samples commonly used as building materials in Turkey was measured by using gamma spectrometry. The activity concentrations, radium equivalent activities (Ra(eq)), representative level index, indoor absorbed dose rate in air values and annual effective dose due to the intake of the above-mentioned radionuclides in the brick and roofing tile samples were estimated to assess the radiation hazard for people living in dwellings made of the materials studied. The measured average activity concentrations of (226)Ra, (232)Th and (40)K were 34 +/- 14, 34 +/- 13 and 462 +/- 175 Bq.kg(-1), respectively, for brick samples. For roofing tile, the average activity concentrations of (226)Ra, (232)Th and (40)K were measured to be 34 +/- 14, 33 +/- 12 and 429 +/- 161 Bq.kg(-1), respectively. The concentrations for these natural radionuclides were compared with the reported data of other countries. The Ra(eq) values of all samples were lower than the limit of 370 Bq.kg(-1), equivalent to a gamma dose of 1.5 mSv.a(-1) recommended by OECD. This study shows that the measured brick and roofing tile samples do not pose any significant source of radiation hazard and are safe to be used as building materials. Moreover, the experimental mass attenuation coefficients (mu/rho) of brick and roofing tile samples were determined in the energy range 80-1332 keV using the gamma ray transmission method. The experimental mass attenuation coefficients were compared with theoretical values obtained using XCOM. It was found that the computed values and the experimental results of this work are in good agreement with those reported in the literature. The chemical compositions and structural analysis (XRD) of the brick and roofing tile samples are also presented. (C) 2011 Elsevier Ltd. All rights reserved.