Yazar "Korkut, Hatun" seçeneğine göre listele

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    Detailed Monte Carlo simulations on secondary radiation emissions of polymer based neutron shielding materials
    (Iop Publishing Ltd, 2024) Korkut, Hatun; Korkut, Turgay
    Since radiation safety is a sensitive issue in terms of health, this situation poses a significant problem. In order to raise awareness among researchers while preparing future studies on this problem, in this study, the interactions between fast neutrons and 10 different polymer-based shielding materials determined from the literature were modeled with the GEANT4 Monte Carlo code. The fast neutron shielding performances of the samples and the emitted secondary radiation and radioactivity have been reported. When evaluated number and mean energies of created particles, in order to solve this problem, the sum of the risk factors obtained by multiplying these values for each sample can provide us with the opportunity to make a more accurate evaluation. When these values are examined, sample P9 is at the top of the risk ranking with a value of 1823472, while sample P6 is at the bottom with a value of 146246. As a result, it has been revealed that these samples, which have good fast neutron shielding properties, also produce high levels of radiation and radioactive nuclei.
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    Improving neutron and gamma flexible shielding by adding medium-heavy metal powder to epoxy based composite materials
    (Pergamon-Elsevier Science Ltd, 2019) Canel, Aysegul; Korkut, Hatun; Korkut, Turgay
    Epoxy resin is cheap, flexible, durable and abundant material. Within this framework, it is a very useful option in a comprehensive application field. In this paper, neutron shields based on epoxy based composite materials were studied by adding different percentages of additive materials as Fe (Iron), Bi (Bismuth), Ta (Tantalum) and WC (Tungsten Carbide). GEANT4 and FLUKA simulation codes were applied simulating and comparing the interactions of 4.5 MeV Am-241-Be neutrons and 1.25 MeV Co-60 source energetic gamma rays with the different specific materials. The best shielding performance results were obtained with the Tantalum-Epoxy sample but all the studied samples demonstrate a good quality as neutron and gamma shielding, when compared to previous results found in literature. Implications of neutron and gamma bombardment were also discussed in the view of a large usage fields.
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    Investigation of high-temperature-resistant rhenium-boron neutron shields by experimental studies and Monte Carlo simulations
    (Springer Singapore Pte Ltd, 2018) Korkut, Turgay; Korkut, Hatun; Aygun, Bunyamin; Bayram, Ozkan; Karabulut, Abdulhalik
    In this study, novel rhenium-boron neutron-shielding high-temperature-resistant materials were designed. The considered samples, Re60-B40, Re58-B42, Re50-B50, and Re40-B60, with different concentrations of rhenium and boron were investigated to elucidate their neutron-shielding performances, and compare them with well-known neutron-shielding materials such as the 316LN quality nuclear steel. In addition to the experimental studies, Monte Carlo simulations were performed using the FLUKA and GEANT4 codes, where 4.5-MeV neutrons emitted by a Am-241-Be source were employed. Experimental equivalent dose rates, simulated track lengths, energy balances, and neutron mass absorption cross sections were discussed in detail.
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    Monte Carlo Simulations of 17.9-22.3 MeV Energetic Proton Irradiation Effects on bcc-Zirconium Fusionic Materials
    (Springer, 2016) Korkut, Hatun; Korkut, Turgay; Kara, Ayhan; Yigit, Mustafa; Tel, Eyyup
    Advanced fusion structural materials (FSMs) have impact role in terms of efficiency of nuclear energy production. Besides engineering and design of fusion reactors, radiation durability of FSMs is another valuable issue that cannot be ignored. 17.9-22.3 MeV proton irradiation of bcc-Zirconium Fusion Structural Material was evaluated by using Monte Carlo based simulation tools. Total binary reaction cross sections were respectively calculated as 1167.6 and 1273.92 mb for 17.3- and 22.3 MeV proton energies via TALYS-1.6 version. Additionally, residual production cross sections and total particle production cross sections were obtained and analyzed by the TALYS code. Radiation damage parameters as Displacement Per Atom (DPA) and Stopping Power (SP) were studied by SRIM-2013 version. FLUKA 2011.1 used for only DPA calculations and making a complete comparison with the other calculation results. SP and Number of Secondaries were found by using GEANT4.10.p.04 version simulations. Natural Zr(p,x) reactions were studied in the given energy values in the plane of reaction probability and radiation damage calculations.
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    Monte Carlo simulations of proton irradiation effects on PTFE, KEVLAR, EFTE, DYNEEMA, and NOMEX polymeric materials used in astronaut space suits
    (Taylor & Francis Ltd, 2023) Korkut, Turgay; Korkut, Hatun
    Astronauts suffer from natural space radiation as high-energetic protons, heavy ions, and secondary particles produced in collisions. Galactic cosmic rays and solar particle events are the basic parts of space radiation spectra. Wears and accessories designs for use by astronauts aim to minimize these deleterious effects of this environment. Polymeric materials are preferred in astronaut suits because they are lightweight, inexpensive, and durable. Teflon, KEVLAR, ethylene tetrafluoroethylene, DYNEEMA, and NOMEX polymeric astronaut wear materials were exposed to high energetic proton irradiations by the use of Monte Carlo simulation tools SRIM-2013 and FLUKA 2011.1. Proton energies are applied as 1, 2, and 3 GeV known as in order of space radiation magnitude. Besides, displacement per atom calculations were done and results were discussed in the plane of structural changes in the given polymeric materials. After interacting with protons with 1, 2, and 3 GeV energies, the material with the lowest Displacement per atom value among the five studied materials is DYNEEMA with values of 1.01E - 25, 9.96E - 26, and 1.00E - 25, respectively. Again, among the materials studied for these three proton energies, DYNEEMA has the highest electronic stopping power values are, respectively, 2.11E - 03, 2.10E - 03, and 2.31E - 03. DYNEEMA has the highest nuclear stopping power values as 2.23E - 07, 1.53E - 07, and 4.27E - 07, respectively.
  • Küçük Resim
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    Semiconductor Type Dependent Comparison of Electrical Characteristics of Pt/InP Structures Fabricated by Magnetron Sputtering Technique in the Range of 20-400 K.
    (Nano-Micro Letters, 2013) Korkut, Hatun
    The paper describes how electrical properties of Pt/InP Schottky diode were affected by semiconductor type. We fabricated Pt/p-InP and Pt/n-InP Schottky diodes and measured electrical characteristics from 20 K to 400 K. Thicknesses of less than 30 nm of platinum were deposited on the two types of indium phosphide substrates using magnetron sputtering technique after the creation of Zn-Au ohmic back contact. We discussed basic diode parameters of idealiy factors, barrier heights and serries resistances of the two type of contacts. Additionly, unusual temperature characteristics of the the diodes were highlighted. These results were evaluated in terms of semiconductor type comparision of Pt/InP Schottky structures.
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    Simulations on the performances of neutron shielding glass materials and secondary radiation risks
    (Pergamon-Elsevier Science Ltd, 2024) Korkut, Hatun; Korkut, Turgay
    Glasses with neutron shielding properties are extremely important for nuclear industries. Neutron interactions with ten different neutron shielding glass types were simulated by using GEANT4 Monte Carlo simulation toolkit. Simulation results were evaluated in terms of shielding performances, deposited energy properties and produced secondary radiation. Important evaluations were made in view of radiation safety, especially on secondary particles and radioactivity resulting from interactions between neutrons and glass samples. All simulated glass samples were found to emit risky secondary particles and radioactive nuclei after interacting with fast neutrons.