Natural radioactivity and evaluation of effective dose equivalent of granites in Turkey

Abstract

Annual effective dose equivalent due to natural gamma radiation from U-238, Th-232 and K-40 have been evaluated from granites in Turkey. Forty samples were taken for spectrometric analysis. Specific concentrations of U-238, Th-232 and K-40 in granite samples were determined. Spectroscopy system was used with 1.8 keV (FWHM) coaxial high purity germanium (HPGe) detector. Average values of concentrations of U-238, Th-232 and K-40 were detected at 15.85, 33.76 and 359 Bq kg(-1), respectively. The average value of radon varies from 0.073 to 0.185 Bq m(-2) h(-1) exhalation depends on the specific concentration of uranium. The dose rate due to this highest activity which have been evaluated by a Monte Carlo transport calculations does not exceed 0.4 mSv a(-1).