Browsing by Author "Kavaz, E."

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Borax Effect on Gamma and Neutron Shielding Features of Lithium Borate Glasses: an Experimental and Monte Carlo Studies
(Iop Publishing Ltd, 2019) Yorgun, N. Yildiz; Kavaz, E.; Tekin, H. O.; Sayyed, M., I; Ozdemir, O. F.
In this work, lithium borate glasses, with (Li2B4O7)(100-x)(Borax)x (x=0,10,20,30,40 wt%) compositions, were prepared with melt quenching technique for investigating their radiation shielding properties. The molar mass, molar volume and density of the glasses were obtained via experimental methods. XRD spectra were acquired to control amorphous structures of the prepared glasses. The mass attenuation coefficient (mu(rho)) for the glasses was measured experimentally at photon energy range between 81 to 383 keV using Ba-133 radioactive point source. The results were compared with the values obtained from MCNPX and WinXCOM programs. It is seen that, the experimental results were in good agreement with findings from MCNPX and WinXCOM programs. The outcomes showed that mass attenuation coefficient, mu(rho), and the effective atomic number, Z(eff), rise with increasing doping rate of borax from 0 to 40% mol. Additionally, it was observed that half value layer (HVL) values of the glasses decreases with increasing borax ratio. Finally, the neutron attenuation skills of the glasses were evaluated by examining the neutron transmission factor and effective removal cross section (Sigma R) parameters. The presence of elements such as H and B in the content of borax mineral significantly increased the Sigma R values of the glasses as expected.
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.
Optical, Structural and Nuclear Radiation Shielding Properties of Li2b4o7 Glasses: Effect of Boron Mineral Additive
(Springer Heidelberg, 2020) Kara, Umit; Kavaz, E.; Issa, Shams A. M.; Rashad, M.; Susoy, G.; Mostafa, A. M. A.; Tekin, H. O.
The glass samples with Li2B4O7 (100 - x) Tincalx (x = 0, 10, 20, 30 and 40 wt%) composition were synthesized by melt-quenching technique (Tincal = Na2B4O7 center dot 10H(2)O). The elemental analysis of Tincal with different compositions is tested using energy-dispersive X-ray technique. Moreover, the surface morphology of fabricated glasses was investigated with scanning electron microscopy. Further, optical properties of fabricated Tincal glasses were evaluated along the wavelength ranged from 200 to 900 nm. Finally, nuclear radiation shielding properties of Tincal glasses were determined for gamma rays, neutrons and charged particles. It is observed from the optical absorption spectra that Tincal 20% and 40% indicated good optical transparency in the visible range of light (400-700 nm). The results showed that Tincal additive improves the gamma protecting capacity of glasses. It was also noticed that the addition of Tincal was also enhanced the neutron absorption of the glasses by increasing the cross section of the neutron and reducing the coherent scattering length.
Structural and Nuclear Radiation Shielding Properties of Bauxite Ore Doped Lithium Borate Glasses: Experimental and Monte Carlo Study
(Pergamon-elsevier Science Ltd, 2019) Kavaz, E.; Tekin, H. O.; Yorgun, N. Yildiz; Ozdemir, O. F.; Sayyed, M. I.
In this work, (Li2B4O7)((100-x)) (Bauxite)(x) (x = 0,10, 20, 30 and 40%) glasses were fabricated by standard melt quenching method. XRD spectra of the glasses were acquired and amorphous structures were verified. The variation of density and molar volume of the bauxite ore doped glasses were examined. The mass attenuation coefficients were measured for 81, 276, 302, 356 and 383 keV of incident photon energies by utilizing transmission method, MCNPX code and WinXCOM program. The obtained results are in good agreement with each other. Other gamma-ray shielding parameters such as half value layer (HVL), and effective atomic number (Z(eff)) for the bauxite doped glasses were also calculated. Additionally, neutron transmission factors and neutron removal cross-sections of the produced glasses were also investigated to interpret the neutron absorption capabilities. It was observed that the obtained parameters changed according to the increasing bauxite percentage of the lithium borate glasses. 40% bauxite doped glass showed the superior gamma and neutron shielding features. The presence of Fe, Ti and Al elements in the Bauxite mine has improved the shielding properties of lithium borate glasses.
Structural and Photon/Neutron Attenuation Features of Pbni/Cnt Nanocomposites: an Experimental Approach
(Pergamon-elsevier Science Ltd, 2023) Yorgun, N. Yildiz; Kavaz, E.; Ulas, B.; Yilmaz, Y.; Kivrak, H.
In this work, PbNi/CNT nanocomposites were prepared by sodium borohydride method at varying metallic molar ratios for determination of their structural and nuclear radiation shielding properties. As-prepared PbNi/CNTs were characterized by using transmission electron microscopy (TEM), scanning electron microscopy energy-dispersive X-ray spectroscopy (SEM-EDX), elemental mapping, and X-ray diffraction (XRD). Average particle sizes of Pb40Ni60/CNT, Pb60Ni40/CNT, Pb80Ni20/CNT, and Pb20Ni80/CNT materials were obtained as 5.6, 3.8, 4.2, and 4.2 nm, respectively. Radiation attenuation properties of the produced nanocomposites were investi-gated experimentally by irradiating the samples with gamma photons in the 34-383 keV energy range. The accuracy of the experimental results was checked with outcomes calculated with EpiXS software. Mass attenu-ation coefficient (MAC) was found in the range of 22.924-0.108 cm2/g, 5.473-0.129 cm2/g, 3.767-0.109 cm2/g, and 4.626-0.128 cm2/g for Pb20Ni80/CNT, Pb80Ni20/CNT, Pb40Ni60/CNT, and Pb60Ni40/CNT samples, respec-tively. Also, other photon shielding parameters (HVL, Zeff, EABF, and EBF) were calculated to make a comprehensive evaluation. The results show that 30% by weight Pb80Ni20 doped CNT has the lowest HVL and buildup factors values and the largest MAC, Zeff values. Finally, macroscopic cross-section values (sigma R) were obtained to estimate the ability of the nanocomposite samples to reduce the energy of fast neutrons. It was revealed that the sigma R values of the samples were in the range of 0.158-0.169 cm-1 and they had higher sigma R values than conventional neutron moderators.
Synergistic Effect of Serpentine Mineral on Li2b4o7 Glasses: Optical, Structural and Nuclear Radiation Shielding Properties
(Springer Heidelberg, 2020) Kara, Umit; Issa, Shams A. M.; Susoy, G.; Rashad, M.; Kavaz, E.; Yorgun, N. Yildiz; Tekin, H. O.
The hypothesis of the present investigation underlined with determination of possible synergistic effects of serpentine mineral additive on Li2B4O7 glasses. A group of Li2B4O7 glasses with serpentine mineral additive were synthesized by melt-quenching technique. The elemental analysis of two different Li2B4O7 glasses with different amount of serpentine additive is tested using energy-dispersive X-ray (EDX) technique. Next, the surface morphology of synthesized serpentine glasses was investigated with scanning electron microscopy (SEM). The optical features of synthesized serpentine glasses were determined along the wavelength ranged from 200 to 900 nm. Lastly, nuclear radiation shielding properties of Li2B4O7 glasses with serpentine mineral additive were determined for gamma rays, neutrons and charged particles. MCNPX (version 2.6.0) general-purpose Monte Carlo code has been utilized for mass attenuation coefficients calculations. The results showed that the spectra are decreasing with wavelength with an observed peak centered at 450 nm. Moreover, it is observed that serpentine mineral additive improves the gamma protecting capacity of Li2B4O7 glasses. It was also noticed that the addition of serpentine mineral also enhanced the neutron and charged particle absorption of the glasses.