Yazar "Sayyed, M., I" seçeneğine göre listele

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    Development and production of metal oxide doped glasses for gamma ray and fast neutron shielding
    (Elsevier, 2020) Aygün, Bünyamin; Sakar, Erdem; Cinan, Esra; Yorgun, Nergiz Yıldız; Sayyed, M., I; Ağar, Osman; Karabulut, Abdulhalık
    In this study, new glasses were designed and produced that did not consist of toxic lead oxide (PbO). Unlike conventional glass with powdered silicon oxide (SiO2) added [cobalt oxide (CoO), cadmium tungsten oxide (CdWO4), bismuth oxide (Bi2O3), chromium oxide (Cr2O3), and boron oxide (B2O3)], new glass specimens were fabricated via melt-quenching. The total macroscopic cross-sections, mean free path, and transmission number were calculated using GEANT4 Monte Carlo code. The equivalent dose rates were measured for 4.5 MeV fast neutrons. Gamma attenuation experiments were conducted at several energies in a range of 53-383 keV. The experimental and theoretical results were compared with those of construction concrete, paraffin, glasses containing lead, borosilicate, normal window, and soda glasses. The new glass minimized both gamma and neutron radiation leaks that may occur in various fields such as radiation treatment, nuclear power plants, radioactive waste transport and storage, and space and laboratory research.
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    An extensive investigation on gamma ray shielding features of Pd/Ag-based alloys
    (Korean Nuclear Soc, 2019) Ağar, Osman; Sayyed, M., I; Akman, Erdi; Tekin, H. O.; Kacal, M. R.
    A comprehensive study of photon interaction features has been made for some alloys containing Pd and Ag content to evaluate its possible use as alternative gamma radiations shielding material. The mass attenuation coefficient (mu/rho) of the present alloys was measured at various photon energies between 81 keV-1333 keV utilizing HPGe detector. The measured mu/rho values were compared to those of theoretical and computational (MCNPX code) results. The results exhibited that the mu/rho values of the studied alloys are in the same line with results of WinXCOM software and MCNPX code results at all energies. Moreover, Pd75/Ag25 alloy sample has the maximum radiation protection efficiency (about 53% at 81 keV) and lowest half value layer, which shows that Pd75/Ag25 has superior gamma radiation shielding performance among the other compared alloys. (C) 2018 Korean Nuclear Society, Published by Elsevier Korea LLC.
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    An extensive investigation on gamma-ray and neutron attenuation parameters of cobalt oxide and nickel oxide substituted bioactive glasses
    (Elsevier Sci Ltd, 2019) Tekin, H. O.; Kavaz, E.; Altunsoy Güçlü, E. E.; Kılıçoğlu, O.; Ağar, Osman; Ergüzel, T. T.; Sayyed, M., I
    This study aimed to investigate the gamma-ray and neutron attenuation parameters of cobalt oxide and nickel oxide substituted ten bioactive glasses. The mass attenuation coefficient (mu/rho) for the selected bioactive glasses was calculated using MCNPX code in photon energy range (0.02 MeV - 20 MeV) and the results were compared with the output of WinXcom software. Other vital gamma-ray attenuation parameters such as half value layer (HVL), tenth value layer (TVL), mean free path (MFP), effective atomic number (Z(eff)), and effective electron density (N-ei) for the selected bioactive glasses were also calculated for each approach. Gamma-ray and neutron transmission factors as well as neutron effective removal cross-sections of each bioactive glass (Sigma R) were also taken into consideration to underline the distinctive parameters. Additionally, exposure buildup factor (EBF) values were found with G-P fitting approach depending on the energy and penetration depths. The results points that, the lowest HVL, TVL and MFP values and the highest neutron effective removal cross-sections (Sigma(R)) values are the characteristics of NiO-4C and CoO-4. The results indicate that the density of the material affects the photon and neutron interaction parameters. While NiO-4C has the lowest TF values for both gamma and neutron radiation, the highest Sigma(R) values are collected from NiO-4C glass material. The gamma and neutron transmission factors (TF) of the studied bioactive glasses support the aforementioned results. The lowest Z(eff) values were generated for 45S5C and 45S5 ordinary glasses, while CoO-4 and NiO-4C doped glasses are having the highest values of Z(eff). EBF values of the glasses were also calculated in the energy range 0.015-15 MeV up to 40 mfp. The smallest EBF values were measured for CoO-4 and NiO-4C glasses. It can be concluded that NiO-4C bioactive glass outperformed compared to other studied samples and is a promising bioactive glass for gamma-ray and neutron attenuation.
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    An investigation on physical, structural and gamma ray shielding features of Dy3+ ions doped Telluroborate glasses
    (Elsevier, 2019) Sathiyapriya, G.; Marimuthu, K.; Sayyed, M., I; Aşkın, A.; Ağar, Osman
    Structural, physical and gamma ray shielding properties of Dy3+ doped telluroborate glasses have been discussed. The molar volume of the glasses is proportional to the TeO2 content. The FTIR studies investigate the expansion of TeO(2 )content and the dynamic change of tetrahedral [BO4] units into trigonal [BO3] units. Using the absorption spectra, optical band gap (E-g) and Urbach's energy (Delta E) values are calculated. The molar volume of oxygen (V-O) and boron-boron separation (< d(B-B) >) values are increasing while there is a fall in oxygen packing density (OPD) from 0% to 40% of TeO2. The ionic nature of the present glasses is analyzed from the bonding parameter (delta), optical basicity (Lambda(th)), covalent and ionic characteristic factors. The gamma photon attenuation investigated employing GEANT4 code. The transmission factor (TF) shows that OTBD sample (0 wt% of TeO2) has the highest TF, while the 4TBD sample (40 wt% of TeO2) has the lowest TF.