Browsing by Author "Cakar, Nurtac"

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Effect of CeO2 and Er2O3 Co-Doping on the Structural and Radiation Shielding Properties of Ceramics: An Experimental and Theoretical Evaluation
(Pergamon-Elsevier Science Ltd, 2026) Oto, Berna; Kavaz, Esra; Cakar, Nurtac; Yildiz, Halime Erzen; Tunc, Hamza
This study investigates the effects of co-doping CeO2 (cerium oxide) and Er2O3 (erbium oxide) on Al2Si2O5(OH)4-KAlSi3O8-SiO2 ceramics, fabricated via conventional firing and sintering, for photon and neutron shielding applications. Experimental measurements were performed using a133Ba source for gamma-ray shielding and a241Am/Be neutron source for neutron shielding. At 81 key gamma-ray energy, the radiation attenuation properties of C (undoped) and Ce15Er15 (co-doped, containing 15 % CeO2 and 15 % Er2O3) ceramics showed an increase in the mass attenuation coefficient from 0.186 to 1.309 cm2/g and in the linear attenuation coefficient from 0.421 to 3.667 cm-1, while the mean free path (mfp) decreased from 2.280 to 0.281 cm, indicating a clear compositional dependence. Theoretical calculations were carried out using the EpiXS program. Among the produced ceramics, the Ce25Er5 sample exhibited the highest neutron absorption rate, reaching 69.39 %. This work presents an innovative approach for co-doping CeO2 and Er2O3 for radiation shielding in ceramics; compared to single oxide doping, this double doping is seen to further enhance both gamma-ray and neutron shielding properties. These results demonstrate that CeO2-and Er2O3-doped ceramics are sustainable, cost-effective, and efficient alternatives for radiation protection in nuclear facilities, medical imaging, and space technologies.
An Experimental Study on Gamma Radiation Attenuation Effectiveness of Magnetite and Serpentine Doped Ceramics
(Pergamon-elsevier Science Ltd, 2024) Oto, Berna; Cakar, Nurtac; Kavaz, Esra; Madak, Zekiye
The present study aims to investigate the gamma-ray (gamma) and fast neutrons attenuation characteristics of magnetite and serpentine doped ceramics via theoretical and experimental. gamma radiation permeability experiments were carried out by preparing a new type of ceramics with magnetite (M) and serpentine (S) additives [0 (C), 10 (M1; S1), 20 (M2; S2), 30 (M3; S3), wt %]. The fabricated shields were exposed to gamma radiation with 81, 160, 223, 302, 356 and 383 keV energies emitted from (133)Barium radioisotope and the measured intensities were detected by Canberra Ultra Ge detector. The parameters such as mass attenuation coefficients (mu(rho)), effective atomic numbers (Z(eff)), electron densities (N-el), half-value thickness (Delta(0.5)) and mean free path (lambda) characterizing the gamma shielding properties of the materials were determined. All theoretical gamma shielding parameters were calculated by running the EpiXS program. And also, exposure (EBF) and energy absorption (EABF) buildup factor values of ceramics were determined at different mean-free paths and photon energies using the EpiXS program. And finally, the macroscopic removal cross-section values (Sigma(R)) for fast neutrons of ceramics were computed. It was found that the density of the ceramic sample increases with the addition of ore. The values of (mu(rho)) are found to depend on the concentration of ore in the ceramics. The mu(rho) values of M3 ceramic are the highest whereas the mu(rho) values of C ceramic are the lowest in all studied ceramics. The M3 has the lowest half-value thickness (Delta(0.5)) and mean free path (lambda) values compared to other studied ceramics. The values of Z(eff) and N-el change as S3
An Experimental Study on the Radiation Shielding Properties of New Type Ceramics Containing Limonite and Hematite Minerals
(Elsevier Science Sa, 2025) Oto, Berna; Kavaz, Esra; Madak, Zekiye; Cakar, Nurtac
In this study, the development and evaluation of new ceramic materials doped with limonite and hematite minerals in terms of their effectiveness in gamma ray and neutron shielding was investigated. The primary aim is to determine gamma-ray shielding parameters for these ceramics, using gamma photon energies emitted from the Barium-133 radioisotope at specific energy levels (81, 160, 223, 302, 356, and 383 keV). Measurements were conducted using a Canberra Ultra Ge detector to detect the intensities of radiations. The mass attenuation coefficient (mu p), half-value thickness (A0.5), mean free path (2) and effective atomic numbers (Zeff) were determined experimentally and theoretically. And, exposure (EBF) and energy absorption (EABF) buildup factor values of ceramics were determined at different mean free paths and photon energies using the EpiXS program. Intercalarily, fast neutron attenuation parameters (ER) of ceramics have also been calculated. The densities of the ceramics increased with the addition of limonite and hematite minerals, ranging from 2.61 g/cm3 to 3.12 g/cm3 as the limonite content increased from 0 wt% to 30 wt %. Similar density variations were observed with the addition of hematite. There is a direct proportional relationship between the density of the ceramics and their shielding effectiveness. The effective atomic numbers (Zeff) were ranked as C G H1 G H2 G H3 G L1 G L2 G L3, indicating that the shielding effectiveness improves with higher doping levels. The L3 ceramic (with 30 % limonite addition) sample exhibited the highest fast neutron removal cross-section values among the tested samples. The findings demonstrate that doping ceramics with limonite and hematite minerals enhances their
I'm Going to See Works of Art: Listening to Children's Narrative Voices
(Routledge Journals, Taylor & Francis Ltd, 2025) Akdogan, Kader Karadeniz; Kurt, Rabia Turgut; Acer, Dilek; Cakar, Nurtac
This study was an exploration of children's agency and autonomy supported through use of clay and museums as learning environments. It was conducted with 48-60-months-old children (M = 52.2) in museum and classroom environments, and focused on a ceramic artist's life story. Using multimodal narration, our research revealed children's agency manifested in stages: before, during, and after museum visits. This study underscored the role of clay in fostering self-directed learning by emphasizing its tactile and open-ended nature. Integrating clay into an immersive museum experience empowers children to make independent decisions and exercise choice, revealing its impact on agency and autonomy.
Improvement of Gamma and Fast Neutron Shielding Behavior in New Ceramic by Adding Ho2O3 and Eu2O3: Experimental and Theoretical Studies
(Springer, 2025) Madak, Zekiye; Oto, Berna; Kavaz, Esra; Cakar, Nurtac
This study is about improving the shielding performance of new types of ceramics produced by adding Ho2O3 (Holmium(III) Oxide) and Eu2O3 (Europium(III) Oxide) to ceramic bodies against nuclear radiation, namely neutrons and photons. Within the scope of the study, photon intensities (I and I-0) emitted by Barium-133 radioisotope were measured experimentally at different energies (81, 160, 223, 302, 356 and 383 keV). Using the obtained results, mass attenuation coefficient (mu rho), linear attenuation coefficient (mu, cm(-)1), half-value thickness (Delta(0).(5)), mean free path (lambda), effective atomic numbers (Zeff) and electron densities (Nel) were derived. Experimental results were compared with theoretical values obtained from the EpiXS program. Equivalent Absorbed Dose (EAD) values characterizing the experimental shielding properties of fast neutrons were measured using BF3 gas proportional neutron detector and 241Am/Be neutron source. Theoretically fast neutron shielding parameters (Sigma R) were also calculated. It is concluded that doping of ceramic bodies with Ho2O3 and Eu2O3 increases both photon and neutron shielding performance. Experimental results demonstrate the potential of these doped ceramics as effective materials for radiation shielding and the possibility of tailoring their performance by adjusting the doping concentrations. It is thought that the data obtained as a result of this research will be very important for applications in nuclear reactors, medical radiation protection and various high radiation environments.
Improvement of Nuclear Photon and Neutron Shielding Performance of Tm2o3 and Dy2o3 Doped Ceramics: an Experimental Study
(Pergamon-elsevier Science Ltd, 2024) Madak, Zekiye; Oto, Berna; Kavaz, Esra; Cakar, Nurtac
In this study, 60KAlSi3O8+10Al2Si2O5(OH)4+(30-x)SiO2+xA2O3 (x = 0, 10, 20, 30 wt% and A = Tm, Dy) ceramics were produced by conventional method to determine their usability as shielding material against ionized gamma radiation. To investigate the ionized photon shielding properties of the fabricated materials, the photon intensities (I and I0) were experimentally measured at 81, 160, 223, 302, 356, and 383 keV energies emitted from 133Barium radioisotope, and then the mass attenuation coefficient (mu p), The linear attenuation coefficients (mu, cm-1), half-value thickness (A0.5), mean free path (A), effective atomic numbers (Zeff) and electron densities (Nel) were derived experimentally. The obtained results were benchmarked with the calculated values from the EpiXS program. Also equivalent absorbed dose (EAD) values for fast neutrons were measured using BF3 gas proportional neutron detector from the Canberra NP-100B series and a241Am/Be neutron source with a 10 mCi activity. In addition, fast neutron shielding parameters (ER) of ceramics were also computed theoretically. The density of the fabricated ceramics varied from 2.607 g/cm3 to 4.392 g/cm3 when the Tm2O3 was raised from 0 wt% to 30 wt%. Likewise, with the addition of Dy2O3 compound, the densities of ceramics varied between 2.607 g/cm3 to 4.152 g/cm3. It was found that nuclear radiation shielding properties evolved by adding Tm2O3 and Dy2O3 compounds in the present ceramic.