Browsing by Author "Oto, B."

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Determination of Gamma and Fast Neutron Shielding Parameters of Magnetite Concretes
(Pergamon-elsevier Science Ltd, 2016) Oto, B.; Gur, A.; Kavaz, E.; Cakir, T.; Yaltay, N.
In this study, some gamma shielding parameters such as mass attenuation coefficient (mu(rho)), effective atomic number (Z(eff)), electron density (N-el) and buildup factors have been investigated for concretes with and without magnetite aggregate. The measurements have been carried out using 1.25 MeV (mean energy of 1.1732 MeV and 1.3325 MeV photons of a Co-60 radioactive source) gamma photons. The theoretical values of mu(rho) have been calculated in the energy range from 1 key to 100 GeV by WinXCom computer code and these values were used in order to calculate the values of Z(eff) and N-el. And fast neutron shielding parameter namely effective removal cross-sections (Sigma(R), cm(-1)) have been calculated. In addition, Energy absorption buildup factors (EABF) and exposure buildup factors (EBF) values of concrete samples have been calculated for photon energy 0.015-15 MeV up to 40 mfp (mean free path) penetration depths. The results of this study showed that the magnetite concrete is more efficient than the ordinary concrete for fast neutrons and gamma rays. (C) 2016 Elsevier Ltd. All rights reserved.
Measurement of the Concentration of 226ra, 232th, 40k in the Soil in Settlements on the Coastline of Lake Van, Turkey
(Oxford Univ Press, 2022) Yorgun, N. Yildiz; Oto, B.; Gur, F.; Tarakci, M.; Yildiz, H. Erzen; Kavaz, E.
In this study, the natural radioactivity level and its effects on the environment of Lake Van, which is the largest lake in Turkey, were investigated extensively. Initially, 254 soil samples have been collected from the districts (Tusba, Edremit, Gevas, Tatvan, Ahlat, Adilcevaz, Ercis) located around the coastline of Lake Van in eastern Turkey. A Na(TI) detector was used to detect activity concentrations of radium (Ra-226), thorium (Th-232) and potassium (K-40) in each collected soil sample. The obtained average results were compared with available data from Turkey and international data base. The average activity in soil samples was measured as 28.0 +/- 3.7-43.6 +/- 2.2 Bq/kg for Ra-226, 27.3 +/- 4.1-55.4 +/- 4.8 Bq/kg for Th-232 and 377 +/- 42- 706 +/- 40 Bq/kg for K-40. It was observed that the average concentrations of Ra-226, Th-232, K-40 (43.6 +/- 2.2, 55.4 +/- 4.8, 706 +/- 40 Bq/kg, respectively) for Tatvan district and (37.0 +/- 3.5, 51.4 +/- 4.2, 479 +/- 41 Bq/kg, respectively) for Ahlat district were higher than both national and international average value. In addition, radiological effect parameters originating from terrestrial natural radionuclides for the study area; gamma dose rate (D-out), annual effective dose equivalent (AEDE), and lifetime cancer development probability (LCR) were calculated. The D-out, AEDE, LCR (83.0 +/- 3.9 nGy/h, 0.102 +/- 0.005 mSv/y, 0.36 +/- 0.02 x 10(-3), respectively) parameters in Tatvan district were found to be above the international allowable value.
Photon Attenuation Properties of Concrete Produced With Pumice Aggregate and Colemanite Addition in Different Rates and the Effect of Curing Age To These Properties
(Pergamon-elsevier Science Ltd, 2015) Yaltay, N.; Ekinci, C. E.; Cakir, T.; Oto, B.
Radiation shielding properties of lightweight concrete produced with pumice aggregate and colemanite addition in different rates and effect of cure ages to the radiation shielding were investigated by using Co-60 (1250 key) radioactive source. Gamma rays were counted by 0.6 cc, Farmer type PTW (TM) Ion chamber. Experimental results were compared with the theoretical values calculated by WinXCom program. Consequently, colemanite addition make enhancement in the radiation shielding of the lightweight concrete, however there is no directly proportional relation between colemanite rate (0.4-2%) and attenuation properties of the lightweight concrete and cure age especially long timed, raises the linear attenuation coefficient and decreases the mean free path values. The theoretical values were obtained as nearby the experimental results, especially in the later cure ages (360 day). (C) 2014 Elsevier Ltd. All rights reserved.
Radionuclide Determination and Radioactivity Evaluation of Surface Soil Samples Collected Along the Ercek Lake Basin in Eastern Anatolia, Turkey
(Elsevier, 2014) Yildiz, N.; Oto, B.; Turhan, S.; Ugur, F. A.; Goren, E.
In the present study, the mean activity concentrations of U-238, Th-232, K-40 and fission products Cs-137 in the soil samples measured by using high-purity germanium gamma spectrometry were 18.9, 27.2, 524.0 and 10.6 Bq kg(-1), respectively. The activity results were analyzed for frequency distribution, tabulated and compared with Turkey and worldwide literatures. Radiological risk evaluation was done by calculating absorbed gamma dose rate in outdoor air and the corresponding annual effective dose due to external exposure to radionuclides distributed in soil. The mean values of the outdoor gamma dose rates and the external annual effective doses received by members of the public from terrestrial radiation and Cs-137 were estimated at 47 nGy h(-1) and 0.6 nGy h(-1) and 57.7 mu Sv and 1.2 mu Sv, respectively. (C) 2014 Published by Elsevier B.V.