Natural radioactivity in different commercial ceramic samples used in Yemeni buildings

In this work we calculated the radioactivity concentrations of the natural radioactive nuclides U-238, Th-232, Ra-226 and K-40 for 10 commercial samples collected from 10 different companies which are used in the construction of Yemeni buildings. Gamma ray spectroscopy was used to analyze the samples and the concentrations of radioisotopes were determined using a hyper-pure germanium (HPGe) detector in Bq/kg dry-weight. The average concentrations of U-238, Th-232, Ra-226 and K-40 were found to be 131.4, 83.55, 131.88 and 400.7 Bq/kg respectively. Different hazard indices were also determined. The results showed that the average radium equivalent activity (Ra-eq), the absorbed dose rate (D-r), the annual effective dose equivalent (AEDE), the external hazard index (H-ex) and representation level index (I-gamma) were: 307.52 Bq/kg, 139.31 nGy/h, 1.40 mSv/yr, 0.83 and 2.15 respectively. The mean value of (Ra-eq) obtained in this study is in good agreement with that of the international value while the mean values of the other indices are found to be higher than the international reference values. The measured activity concentrations for these radionuclide were compared with the reported data obtained from similar materials used in other countries. (C) 2013 Elsevier Ltd. All rights reserved.