Yazar "Okuducu, S." seçeneğine göre listele
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Öğe The effect of the initial exciton numbers on Fe-54,Fe-56(p, xp) Pre-Equilibrium Reactions(Maik Nauka/Interperiodica/Springer, 2011) Bolukdemir, M. H.; Tel, E.; Aydin, A.; Okuducu, S.; Kaplan, A.In pre-equilibrium nuclear reactions, the geometry-dependent hybrid model is applied with the use of the neutron and proton densities to investigate the effect of initial exciton numbers on the nucleon emission spectra. The initial exciton numbers calculated with the theoretical neutron and proton densities have been obtained within the Skryme-Hartree-Fock method with SKM* and SLy4 forces on target nuclei in the Fe-54,Fe-56(p, xp) reaction at 61.5-MeV incident proton energy by using a new calculationmethod of Tel et al. Also, the differences between the initial exciton numbers for protons and neutrons as a function of nuclear radius, focusing on systematic discrepancies correlated to differences in the proton and neutron densities have been investigated.Öğe Improved Formula for (n,He-3) Fusion Reactions Cross Sections Using Optical Model(Springer, 2010) Bolukdemir, M. H.; Tel, E.; Akti, N. N.; Aydin, A.; Okuducu, S.Non-elastic cross-sections have been calculated by using optical model for (n, He-3) reactions at 14-15 MeV energy. The new empirical formula including optical model non-elastic effects by fitting two parameters for the (n, He-3) reaction cross-sections have been suggested. The excitation function character and reaction Q-values depending on the asymmetry term effect for the (n, He-3) reaction have been investigated. The obtained cross-section formula with new coefficients has been compared with the experimental data and the other fitting formulae existed in the literature and discussed. It has seen that the fit of new formula in this paper is greatly improved with the experimental data.Öğe Investigation of neutron skin effect with density dependence by using a new calculation method for initial exciton numbers on pre-equilibrium reactions(Iop Publishing Ltd, 2009) Tel, E.; Bolukdemir, M. H.; Okuducu, S.; Aydin, A.; Kaplan, A.In this study, we investigated the pre-equilibrium effect by using a new evaluated geometry-dependent hybrid model and a neutron skin effect with density dependence for the (204,206,207)Pb(p, xn) reaction at 25.5MeV incident proton energy. We calculated the initial exciton numbers obtained from the modified Skyrme force based on fitting the fission barriers of heavy deformed nuclei (SKM*) and SLy4 for proton induced reaction on target nuclei (204,206,207)Pb. We calculated, by using a new calculation method, the initial neutron and proton exciton numbers for (204,206,207)Pb from the neutron and proton density and we investigated the shell effect by using an effective nucleon-nucleon interaction with Skyrme force. We also compared the geometry-dependent hybrid model (GDH), newly evaluated with the initial exciton number calculations of the neutron emission spectra of the (204,206,207)Pb(p, xn) reaction, with the values reported in the literature at 25.5MeV incident proton energy. The obtained results were investigated and compared with the pre-equilibrium calculations and experimental results.Öğe A new empirical formula for 14-15 MeV neutron-induced (n, p) reaction cross sections(Iop Publishing Ltd, 2003) Tel, E.; Sarer, B.; Okuducu, S.; Aydin, A.; Tanir, G.In this study, we have suggested a new empirical formula to reproduce the cross sections of the (n, p) reactions at 14-15 MeV for the neutron incident energy. This formula obtained using the asymmetry parameters represents a modification to the original formula of Levkovskii. The resulting modified formulae yielded cross sections, representing smaller chi(2) deviations from experimental values, and values much closer to unity as compared with those calculated using Levkovskii's original formula. The results obtained have been discussed and compared with the existing formulae, and found to be well in agreement, when used to correlate the available experimental sigma(n, p) data of different nuclei.Öğe New Evaluated Semi-Empirical Formula Using Optical Model for 14-15 MeV (n, t) Reaction Cross Sections(Springer, 2009) Tel, E.; Durgu, C.; Aydin, A.; Boeluekdemir, M. H.; Kaplan, A.; Okuducu, S.In the next century the world will face the need for new energy sources. Nuclear fusion can be one of the most attractive sources of energy from the viewpoint of safety and minimal environmental impact. Fusion will not produce CO2 or SO2 and thus will not contribute to global warming or acid rain. Achieving acceptable performance for a fusion power system in the areas of economics, safety and environmental acceptability, is critically dependent on performance of the blanket and diverter systems which are the primary heat recovery, plasma purification, and tritium breeding systems. Tritium self-sufficiency must be maintained for a commercial power plant. The hybrid reactor is a combination of the fusion and fission processes. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. So working out the systematics of (n, t) reaction cross-sections are of great importance for the definition of the excitation function character for the given reaction taking place on various nuclei at energies up to 20 MeV. In this study, we have calculated non-elastic cross-sections by using optical model for (n, t) reactions at 14-15 MeV energy. We have investigated the excitation function character and reaction Q-values depending on the asymmetry term effect for the (n, t) reaction cross-sections. We have obtained new coefficients for the (n, t) reaction cross-sections. We have suggested semi-empirical formulas including optical model nonelastic effects by fitting two parameters for the (n, t) reaction cross-sections at 14-15 MeV. We have discussed the odd-even effect and the pairing effect considering binding energy systematic of the nuclear shell model for the new experimental data and new cross-sections formulas (n, t) reactions developed by Tel et al. We have determined a different parameter groups by the classification of nuclei into even-even, even-odd and odd-even for (n, t) reactions cross-sections. The obtained cross-section formulas with new coefficients have been discussed and compared with the available experimental data.Öğe The Study of (n,d) Reaction Cross Sections for New Evaluated Semi-Empirical Formula Using Optical Model(Springer, 2009) Boeluekdemir, M. H.; Tel, E.; Okuducu, S.; Aydin, A.Nuclear fusion can be one of the most attractive sources of energy from the viewpoint of safety and minimal environmental impact. The neutron scattering cross sections data have a critical importance on fusion reactor (and in the fusion-fission hybrid) reactors. So, the study of the systematic of (n,d) etc., reaction cross sections is of great importance in the definition of the excitation function character for reaction taking place on various nuclei at energies up to 20 MeV. In this study, non-elastic cross-sections have been calculated by using optical model for (n,d) reactions at 14-15 MeV energy. The excitation function character and reaction Q-values depending on the asymmetry term effect for the (n,d) reaction have been investigated. New coefficients have been obtained and the semi-empirical formulas including optical model non-elastic effects by fitting two parameters for the (n,d) reaction cross-sections have been suggested. The obtained cross-section formulas with new coefficients have been compared with the available experimental data and discussed.Öğe A Study on Be8-18 Isotopes Used on Neutron Multiplier in Reactor Design(Springer, 2011) Tel, E.; Akti, N. N.; Okuducu, S.; Aydin, A.; Sahan, M.; Ugur, F. A.; Sahan, H.Neutronic characterization and development of structural materials, neutron multiplier materials, tritium breeders are primarily important for fusion and hybrid reactors. In order to improve neutron economy, beryllium, lead, bismuth, zirconium are considered and used as neutron multiplier materials in fusion and hybrid reactor design. In this study, rms charge radii, neutron radii, mass radii and neutron skin thickness were calculated for Be8-18 isotopes nuclei. The neutron and proton density are calculated for Be isotopes. The results obtained were compared with the experimental and theoretical results of other researchers by using Hartree-Fock method with an effective interaction with Skyrme forces.Öğe A Systematic Study Of Equilibrium And Pre-Equilibrium (P, N) Reaction Mechanisms Cross-Sections At Intermediate Energies For 25 < A < 240 Target Nuclei(World Scientific Publ Co Pte Ltd, 2009) Kaplan, A.; Tel, E.; Aydin, A.; Okuducu, S.In this present study, by using equilibrium and pre-equilibrium reaction mechanisms, the (p, n) cross-section values for some target (A = 25-240) nuclei were investigated in a range of 10-40 MeV incident energy. The excitation functions for pre-equilibrium calculations were newly calculated by using hybrid model, geometry dependent hybrid model, full-exciton model, and cascade exciton model. The reaction equilibrium component was calculated with a traditional compound nucleus model developed by Weisskopf-Ewing. Calculation results were compared with the available excitation functions measurements in literature.
