Out-door radiation level measurement in Abeokuta, Nigeria, by thermoluminescent dosimetry

Abstract

Environmental radiation level and its spatial variability have been investigated at 34 locations in Abeokuta and environs using the technique of thermoluminescent dosimetry (TLD) with LiF phosphor calibrated with a 137Cs standard source operating at a Secondary Standard Dosimetry Laboratory (SSDL). The human dose equivalent due to outdoor exposure in the city range between 0.19 and 1.64 mSv per year with a mean of 0.45 mSv/y and standard deviation of 0.27 mSv/y. Oke-Sabo area of the city has the least radiation dose rate while Obantoku area has the upper limit. Taking this as the profile of integrated natural background radiation dose rate from all sources in the city and comparing with measurements of terrestrial radiation dose in a previous survey, the mean dose rate from extraterrestrial (cosmic) radiation has been estimated to be about 0.18 mSv/y in Abeokut Keywords: Environmental radiation, thermoluminescent dosimetry, Abeokuta, outdoor Radiation exposure. Nigerian Journal of Physics Vol. 18 (1) 2006: pp. 121-126