Estimation of Radon Exhalation Rate, Natural Radioactivity and Radiation Doses in Mosaic Samples

Abstract

 In the present study we have made measurement of radon exhalation rate from mosaic of different brands and colours, commonly used  as building construction materials in India. Out of total 27 samples collected 10 were from Jaipur, 8 from Kishangarh and 9 from Ajmer. Can technique using LR-115 type II solid state nuclear track detector has been employed for the measurement of radon activity and radon exhalation rate. Radon activity varies from 27.52 Bq m^-3 to 101.12 Bq m^-3 with an average value of 54.95 Bq m^-3, exhalationrate varies from 491.43 mBq m^-2 h^-1 to 1805.71mBq m^-2 h^-1 with an average value of 981.27 mBq m^-2 h^-1 while effective dose equivalent varies from 34.68 µSv  y^-1 to 127.44 µSv  y^-1 with an average value of 69.26 µSv  y^-1. Natural radioactivity in mosaic samples has been measured by low level gamma ray spectrometer. The activity concentrations of ²³⁸U and ²³²Th varies from 3.33± 1.8 to 128.18± 2.44 Bq kg^-1 with an average value of 30.67± 1.06 Bq kg^-1 and from 6.25±0.28 to 51.69± 1.42 Bq kg^-1 with a mean value of 24.39±0.83 Bq kg^-1 respectively. ⁴⁰K in mosaic samples ranges from 0 to 833.67± 9.7 Bq kg^-1 with an average value of 270.29± 3.74 Bq kg^-1. Absorbed gamma dose rate varies from min. value of 5.31 nGy h^-1 to max. value 125.20 nGy h^-1. The corresponding indoor and outdoor annual effective doses vary from 0.03 to 0.25 mSv y^-1 and 0.01 to 15 mSv y^-1. The calculated values of H_ex for mosaic samples vary from 0.03 to 0.71.