Analysis of the reaction Q -value effect using newly evaluated empirical formulas of (n, 2 n) cross-sections near 14.6 MeV

Empirical formulas in determining the cross-sections play an important role at the energies of which there are no experimental data scattered about. The purpose of the present communication is to further improve the formulas of the cross-section of (n, 2n) reactions at the energies near 14.6MeV. A systematics for the evaluation of these cross-sections is studied. We present the empirical formulas based on the statistical theory of nuclear reactions in connection with the compound nucleus. The new empirical formulas are found by using the experimental cross-sections as a function of the reaction Q-value. Thus, the new formulas provide the best description of the existing measured data compared with systematics suggested earlier by other authors

Theoretical predictions of excitation functions of neutron-Induced reactions on Li-6, Be-9, C-12 and Na-23 nuclei at low energies

WOS: 000350887400023In the present work, the excitation functions of neutron reactions Li-6(n,p)He-6, Be-9(n,alpha)He-6, C-12(n,p)B-12, C-12(n,alpha)Be-9, Na-23(n,p)Ne-23, Na-23(n,2n)Na-22 and Na-23(n,alpha)F-20 produced by the incident neutrons were studied for the investigation of fusion structural materials. Tel et al. formulae (for sodium isotopes), the codes ALICE-ASH and CEM03.01 (for all nuclei) were employed for the obtaining of cross-sections. In addition, hybrid model and geometry-dependent hybrid model with pre-equilibrium emissions, and Weisskopf Ewing model with the equilibrium emissions, and the cascade-exciton model with cascade interactions were used to calculate the excitations curves. The obtained results and Tendl-2011 library data were compared with the experimental literature values. Finally it is to mention that the cross-section data obtained may be useful for the safety design of future fusion reactors

Reaction cross sections in the interactions of neutrons with Yttrium nucleus

WOS: 000362957300023In this research, the cross sections of the nuclear reactions Y-88(n, 2n)Y-87, Y-89(n, 2n)Y-88, Y-89(n, 3n)Y-87, Y-89(n, p)Sr-89, Y-89(n, d)Sr-88, Y-90(n, 2n) Y-89 and Y-90(n, p)Sr-90 have been calculated using advanced nuclear models at incident neutron energies up to 40 MeV. The theoretical values of nuclear cross sections for these reactions have been estimated by the computer codes ALICE-ASH, PCROSS and CEM03.01. Effect on the cross sections of level density parameters used in the calculations has also been discussed. Finally, the excitation function systematics have been observed with a significant contribution to obtain the nuclear cross sections for bombardment energy range of 14-15 MeV

Theoretical study of deuteron induced reactions on Li-6,Li-7, Be-9 and F-19 targets

WOS: 000334145300009The nuclear reactions of the deuteron particles with light nuclei have been extensively investigated in the history of nuclear physics. In this work, the cross-sections of deuteron reactions Li-6(d,n)Be-7, Li-6(d,t)Li-5, Li-7(d,2n)Be-7, Li-7(d,p)Li-8, Li-7(d,t)Li-6, Be-9(d,p)Be-10, Be-9(d,t)Be-8, F-19(d,n)Ne-20 and F-19(d,p)F-20 were studied for the investigation of structural fusion materials. Excitation functions of these reactions were determined by using ALICE-ASH code considering equilibrium (EQ) and preequilibrium (PEQ) effects. The calculated cross-sections, experimental results and TENDL-2011 library data are presented in graphical form

Study on cross section calculations for (n,p) nuclear reactions of cadmium isotopes

A theoretical study of the cross sections of (n,p)reactions on Cadmium isotopes has been performed using the Hauser-Feshbach model, Weisskopf-Ewing model, Exciton model, Two-component exciton model and Geometry dependent hybrid model for the incident energies from the reaction threshold to 20MeV. Furthermore, the empirical formulae based on the different systematics at the energies near 14.5MeV were used for calculating the (n,p)nuclear cross sections. Finally, the results of the present paper are discussed and compared with the experimental cross sections and TENDL-2017 data found in the literature...

Calculations of proton emission cross sections in deuteron induced reactions of some fusion structural materials

WOS: 000317973500001The growing demands for energy consumption have led to the increase of the research and development activities on new energy sources. Fusion energy has the highest potential to become a very safe, clean and abundant energy source for the future. To get energy from fusion are needed for development of fusion reactor technology. Particularly, the design and development of international facilities as International Thermonuclear Experimental Reactor and International Fusion Material Irradiation Facility requires for the cross-section data of deuteron induced reactions. Moreover, the selection of fusion structural materials are an indispensable component for this technology. Therefore, the cross-section data of deuteron induced reactions on fusion structural materials are of great importance for development of fusion reactor technology. In this study, reaction model calculations of the cross sections of deuteron induced reactions on structural fusion materials such as Al-27, Co-59, Mn-55, Cr-50, Cr-54, Ni-64, Ag-109, W-184 and W-186 have been carried out for incident energies up to 50 MeV. In these calculations, the pre-equilibrium and equilibrium effects for (d,p) stripping reactions have been investigated. The pre-equilibrium calculations involve the new evaluated the geometry dependent hybrid model and hybrid model. Equilibrium effects are calculated according to the Weisskopf-Ewing model. In the calculations the program code ALICE/ASH was used. The calculated results are discussed and compared with the experimental data taken from the literature

On the behavior of cross-sections of charged particle-induced reactions of Ta-181 target

WOS: 000442555000007The production of nuclear energy from fusion reaction with no CO2 emission is one of the most attractive sources for the future. The unprecedented physical and mechanical properties for structural materials are very important in the nuclear fusion reactor design. So, tantalum material is a valuable candidate for plasma-facing materials in the fusion devices. In this paper, nuclear excitation functions for the Ta-181(p, n) W-181, Ta-181(p, 2n) W-180, Ta-181(p, 4n) W-178, Ta-181(d, 2n) W-181, Ta-181(a, n) Re-184 and Ta-181(a, 2n) Re-183 reactions are obtained using the nuclear codes TALYS 1.8 and ALICE/ASH. The contribution of pre-equilibrium and equilibrium processes in these reactions is investigated. In the calculations, the Weisskopf-Ewing and Hauser-Feshbach formalisms for the equilibrium particle emission, and the two-component exciton, hybrid and geometry-dependent hybrid formalisms for the pre-equilibrium particle emission are used. Hence, the cross-sections calculated are compared with the measured values. It is observed that the cross-section results of the geometry-dependent hybrid model match fairly well with the experimental measurements

Burnup calculations using serpent code in accelerator driven thorium reactors

WOS: 000323402800004In this study, burnup calculations have been performed for a sodium cooled Accelerator Driven Thorium Reactor (ADTR) using the Serpent 1.1.16 Monte Carlo code. The ADTR has been designed for burning minor actinides, mixed Th-232 and mixed U-233 fuels. A solid Pb-Bi spallation target in the center of the core is used and sodium as coolant. The system is designed for a heating power of 2 000 MW and for an operation time of 600 days. For burnup calculations the Advanced Matrix Exponential Method CRAM (Chebyshev Rational Approximation Method) and different nuclear data libraries (ENDF7, JEF2.2, JEFF3.1.1) were used. The effective multiplication factor change from 0.93 to 0.97 for different nuclear data libraries during the reactor operation period.Karamanoglu Mehmetbey University Scientific Research Project [20-M-11]This work was supported by Karamanoglu Mehmetbey University Scientific Research Project (20-M-11)

Calculations of (n,alpha) cross sections on some structural fusion materials for fusion reactor technology

WOS: 000317973500004The knowledge of cross section for emission of light charged particles (p, d, t, and alpha) induced by fast neutrons on structural fusion materials has a critical importance on fusion reactors. The gas production arising from (n,p) and (n,alpha) reactions causes seriously radiation damage in fusion reactor structure. The radiation damage in fusion related materials is a large problem need to be overcome for development of fusion reactor technology. Particularly, the (n,alpha) reaction cross section data are required to estimation of the radiation damage effects on structural fusion materials. Therefore, the cross section data for (n,alpha) reaction induced by fast neutrons are of increasing importance for the success of future fusion reactors. In this study, reaction model calculations of the cross sections of neutron induced reactions on structural fusion materials such as (29) Si, (30) Si, (48) Ti, (50) Ti, (50) Cr, (54) Cr, (54) Fe and (58) Fe have been investigated. The new calculations on the excitation functions of (29) Si (n,alpha) (26) Mg, (30) Si (n,alpha) (27) Mg, (48) Ti (n,alpha) (45) Ca, (50) Ti (n,alpha) (47) Ca, (50) Cr (n,alpha) (47) Ti, (54) Cr (n,alpha) (51) Ti, (54) Fe (n,alpha) (51) Cr and (58) Fe (n,alpha) (55) Cr have been carried out for incident neutron energies up to 30 MeV. In these calculations, the pre-equilibrium and equilibrium effects for (n,alpha) reactions have been investigated. The pre-equilibrium calculations involve the new evaluated the geometry dependent hybrid model, hybrid model and the cascade exciton model. The equilibrium effects of the excitation functions for the investigated reactions are calculated according to the Weisskopf-Ewing model. Also in the present work, the (n,alpha) reaction cross sections have calculated by using evaluated empirical formulas developed by Tel et al. at 14-15 MeV energy. The calculated results have been discussed and compared with the available experimental data and found agreement with each other

Overview of anti-vegf treatment regimens and new agents in age-related macular degeneration

© 2021 Gazi Eye Foundation. All rights reserved.Age-related macular degeneration (AMD), which can result in central vision loss, is among the leading causes of blindness worldwide. The beginning of the anti-vascular endothelial growth factor (anti-VEGF) era has revolutionized the treatment of AMD. The effi cacy of anti-VEGFs (bevacizumab, ranibizumab and afl ibercept) has been proven in important clinical studies such as ANCHOR, MARINA and VIEW, leading to the widespread use of these agents in the treatment of AMD. This review focuses on important clinical studies using 3 anti-VEGF agents and their link with real-world evidence including data point specifi c to our country. Also, the effi cacy of anti-VEGF agents and real-life treatment regimens will be reviewed. New treatments under development in the search for the ideal agent for AMD treatment will also be discussed