Evaluation of absorbed dose rate and annual effective dose equivalent due to terrestrial gamma radiation in rocks in a part of Southwestern Nigeria.
The average outdoor absorbed dose rate in air and the average annual effective dose equivalent due to terrestrial gamma radiation from 40K, 238U and 232Th in rocks in Ondo and Ekiti States, Southwestern Nigeria have been evaluated from measurements of the concentrations of these radionuclides in this environmental material. The concentration measurements were obtained using a very sensitive gamma spectroscopic system consisting of a 7.6 cm x 7.6 cm NaI(Tl) scintillation detector coupled to a computerised ACCUSPEC installation. The average absorbed dose rate and average annual effective dose equivalent was found to be 8.33 +/- 2.76 nGy x h(-1) and 8.7 +/- 2.9 microSv x y(-1) respectively.
Department of Physics, Federal University of Technology, Akure, Ondo State, Nigeria.
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Ajayi
D001417:Background Radiation; D004784:Environmental Monitoring / Q000706:statistics & numerical data*; D005720:Gamma Rays; D006801:Humans; D008903:Minerals / Q000032:analysis*; D009549:Nigeria; D011197:Potassium Radioisotopes / Q000032:analysis; D011874:Radiometry / Q000379:methods*; D012016:Reference Values; D012588:Scintillation Counting; D012680:Sensitivity and Specificity; D013051:Spectrometry, Gamma; D013910:Thorium / Q000032:analysis; D014501:Uranium / Q000032:analysis
D008903:Minerals; D011197:Potassium Radioisotopes; D014501:Uranium; D013910:Thorium