Yazar "Baltakesmez, Ali" seçeneğine göre listele

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    Experimental investigation of radiation shielding performances of some important AISI-coded stainless steels: Part I
    (Pergamon-Elsevier Science Ltd, 2020) Alim, Bunyamin; Sakar, Erdem; Baltakesmez, Ali; Han, Ibrahim; Sayyed, M., I; Demir, Lutfu
    The investigation of radiation shielding performances of AISI-302, 304, 321 and 430 stainless steels which have wide range of application because of their superior mechanical properties, temperature and corrosion resistances was aimed in this study. In accordance with this purpose, photon-shielding parameters of these stainless steels were calculated both experimentally and theoretically. These parameters calculated are linear attenuation coefficient, mass attenuation coefficient, mean free path, half-value layer, quarter-value layer, tenth-value layer, total atomic cross-section, total electronic cross-section, effective atomic number, effective electron number and effective conductivity. They were experimentally measured at twenty-three different energies in the range 22 keV and 1333 keV. The photon energies were obtained from seven different radioactive sources (Na-22,Co- 60, Am-24(1) (109)cd , (137)cs, Eu-152 and Ba-133) . The Si(Li) and NaI(Tl) detectors were separately used taking into account of energy-efficient regions to counting process at narrow-beam transmission geometry. In addition, all these parameters were computed at the 15 keV-15 MeV wide energy range, theoretically. In order to make a satisfying assessment about radiation shielding capabilities of AISI 302, 304, 321 and 430 alloys, all calculations were also made for ordinary, steel-scrap and steel-magnetite concretes (Fe-based steel concretes) that are most commonly used as shielding material in many nuclear applications. According to the results obtained, it was observed that the radiation shielding performances of AISI 300 austenitic stainless steel series with containing Ni are superior to that of both AISI 430 ferritic stainless steel and examined concretes.
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    MoO3 reinforced Ultra high molecular weight PE for neutrons shielding applications
    (Pergamon-Elsevier Science Ltd, 2020) Sayyed, M., I; Abdalsalam, Alyaa H.; Taki, Malaa M.; Mhareb, M. H. A.; Alim, Bunyamin; Baltakesmez, Ali; Sakar, Erdem
    Structural, Morphological and neutron attenuation properties of ultrahigh molecular weight polyethylene (UHMWPE) reinforced with molybdenum trioxide composite material obtained by solid state mixing of pellets and powder components via hot pressing have been studied. In this work, Ultra high molecular weight poly-ethylene and MoO3 has been utilized with different concentration using a hot compression iron mold. The changes in the microstructure of the prepared polymer and its particulate composites were evaluated by SEM. In order to investigate the quantitative of all elements used in these samples, we utilized Energy-dispersive X-ray spectroscopy (EDX) to present the profiles of synthesized samples which show a clear peaks C (carbon), and Mo (Molybdenum). The X-ray diffraction of all samples was examined to study the modification of the phase and lattice for UHMWPE before and after the addition of molybdenum trioxide (MoO3). Raman analysis was utilized to explore the crystallinity, molecular interactions, phase, polymorphy, and chemical structure. This technique is based on non-destructive interaction between light with the chemical bonds inside a material. The Raman spectrum for the current work presented within the range of 150-1600 cm(-1). In order to understand the neutron shielding performance for the fabricated UHMWPE with different concentrations of MoO3, 241 Am/Be fast neutron source was used to determine the fast neutron radiation equivalent dose rate. The background absorbed dose rate was measured as 0.98 (+/- 0.017) (mu Sv/h). It was seen that the addition of MoO3 into the UHMWPE enhances the neutron shielding. The dose released from the source was absorbed by 7.71 ( +/- 1.3) %, 18.48 (+/- 2.9) %, 22.26 (+/- 2.4) %, 24.07 (+/- 1.8) % and 26.17 (+/- 1.3) % from UHMWPE with 1, 2, 3, 4 and 5% of MoO3 respectively. Additionally, GEANT4 10.02. p01 version was used to calculate total macroscopic crosssections (TMCS) for the MoO3 doped UHMWPE. According to the results obtained from GEANT4, it was observed that the TMCS values of the UHMWPE increase with increment of the mole fraction of the MoO3 in the structure of UHMWPE examined and that the 5.0% MoO3 sample has the best neutron shielding ability.
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    A surveying of photon and particle radiation interaction characteristics of some perovskite materials
    (Pergamon-Elsevier Science Ltd, 2021) Sakar, Erdem; Alim, Bunyamin; Ozpolat, Ozgur Firat; Sakar, Betul Ceviz; Baltakesmez, Ali; Akbaba, Ugur
    In this study, we aimed to determinate of the photon and particle radiation interaction parameters of six different perovskites to help use perovskite materials in radiation applications. The parameters that are aimed to be investigated are MAC, HVL, MFP, Z(eff), N-eff, C-eff and EBF for photons, range values for charged particles, and FNRCS values for neutrons. The photon-interaction parameters the FNRCS values of the perovskites were calculated using Phy-X/PSD software in the energy range of 1 keV-100 GeV for photons and at 4.5 MeV energy for neutrons, respectively. Moreover, the range values of the perovskites were calculated using SRIM Monte Carlo software (for H+ and He++ particles) and ESTAR NIST software (for electrons) in the energy range from 0.01 MeV to 20 MeV. In order to make a notable assessment about the radiation interaction possibilities of the perovskites, the results obtained were compared with some standard shielding materials. According to the results obtained for all radiation types examined, it was determined that all calculated parameters were strongly dependent on both the type and energy of the radiation and the type of material. Additionally, it was observed that the order of preference of the examined materials as armor material in radiation applications varies according to the radiation type and energy. Consequently, it was determined that while the most suitable material in terms of photon shielding is P6 (Cs2SnI6) inorganic perovskite among the perovskites examined, this sample is not suitable material for neutron shielding applications.