Geometry Dependent Hybrid Model Research Articles

(3He,xn) Reaction Cross-Section Calculations for the Structural Fusion Material 181Ta in the Energy Range of 14–75 MeV

The theoretical neutron-production cross-sections produced by 181Ta(3He,xn)184−xRe reactions (x = 1–7) for structural fusion material 181Ta in 3He-induced reactions have been performed in the incident 3He energy range of 14–75 MeV. Reaction cross-sections, based on theoretical pre-equilibrium nuclear reaction models, have been calculated theoretically by means of the TALYS 1.6 two component exciton, EMPIRE 3.1 exciton, ALICE/ASH geometry dependent hybrid (GDH) and ALICE/ASH hybrid models. The neutron-production cross-section results of the models have been compared with the each other and against the experimental nuclear reaction data (EXFOR). Except the 181Ta(3He,2n)182Re and 181Ta(3He,7n)177Re reactions, the ALICE/ASH cross-section calculations show generally agreement with the experimental values for all reactions used in this study. The ALICE/ASH–GDH model can be suggested, if the experimental data are unavailable or are improbably to be produced because of the experimental troubles.

New Evaluation of n+63,65Cu Nuclear Cross Section Data up to 200 MeV Neutron Energy

This work presents newly evaluated general purpose nuclear data files for the n+63Cu and n+65Cu reactions with upper neutron incident energy 200 MeV. Special attention was devoted to the accuracy and consistency of the evaluated data. The TALYS code was used for the nuclear model simulations in the energy range from 1 keV to 200 MeV. To improve the pre-equilibrium particle emission the Geometry-Dependent Hybrid model (GDH) was included in TALYS as a new option. The nuclear model parameters were properly adjusted to achieve the best description of the available measured data. New resonance data based on recent measurements and their covariances were included in the files. A set of covariance data for all nuclear reactions was also prepared making use of the Unified Monte Carlo Approach.

Nuclear model calculation for production of 18F, 22Na, 44,46Sc, 54Mn, 64Cu, 68Ga, 76Br and 90Y radionuclides used in medical applications

The nuclear data for production of the radionuclides 18F, 22Na, 44Sc, 46Sc, 54Mn, 64Cu, 68Ga, 76Br and 90Y via (d,α) reactions on 20Ne, 24Mg, 46Ti, 48Ti, 56Fe, 66Zn, 70Ge, 78Kr and 92Zr target materials, respectively, have been investigated for incident deuteron energy up to 30MeV. The calculations performed to obtain these nuclear data were based on the equilibrium Weisskopf–Ewing (WE), the pre-equilibrium hybrid and the geometry dependent hybrid (GDH) models of nuclear reactions. ALICE/ASH code is used to define the shape of excitation functions and the results obtained from the calculations are discussed and compared with existing experimental values and TENDL library data.

Cross sections of proton-induced reactions on 152Gd, 155Gd and 159Tb with emphasis on the production of selected Tb radionuclides

Cross sections are presented for various Dy, Tb and Gd radionuclides produced in the proton bombardment of 159Tb as well as for the reactions 152Gd(p,4n)149Tb and 155Gd(p,4n)152Tb up to 66MeV. The experimental excitation functions are compared with theoretical predictions by means of the geometry-dependent hybrid (GDH) model as implemented in the code ALICE/ASH, as well as with values from the TENDL-2012 library and previous literature experimental data, where available. Physical yields have been derived for the production of some of the medically important radioterbiums, namely 149Tb (radionuclide therapy), 152Tb (PET) and 155Tb (SPECT). The indirect production of high-purity 155Tb via the decay of its precursor 155Dy is reported. The possibility of a large-scale production facility based on a commercial 70MeV cyclotron is also discussed.

Cross-section calculations of proton induced (p,n) and (p,2n) reactions for production of diagnostic 67Ga, 81Rb, 111In, 123,124I, 123Cs and 123Xe radioisotopes

Investigation of pre-equilibrium (PEQ) and equilibrium (EQ) effects on proton induced reactions for production of radioisotopes are very important. Therefore, in this study, we have calculated the PEQ and EQ cross-sections for 67Zn(p,n)67Ga, 68Zn(p,2n)67Ga, 82Kr(p,2n)81Rb, 111Cd(p,n)111In, 112Cd(p,2n)111In, 123Te(p,n)123I, 124Te(p,2n)123I, 124Te(p,n)124I and 124Xe(p,2n)123Cs reactions for production diagnostic radioisotopes. Calculations have been performed by using the hybrid model, geometry dependent hybrid model and full exciton model of PEQ reaction mechanism with 1–40 MeV proton incident energy. We have also investigated the EQ effects on these reactions using the Weisskopf–Ewing model in the same energy range. The excitation functions including the PEQ and EQ effects on these reactions are evaluated by using the ALICE/ASH (2006) and the TALYS 1.4 (2011) codes. Our results have shown that using these codes is suitable for production diagnostic isotopes mentioned above. To obtain excitation functions for producing the diagnostic radioisotopes the PEQ mechanism has been found more dominant than that of the EQ. The results are discussed and compared with the available experimental data.

Pre-equilibrium neutron-emission spectra of 238U with an effective nucleon–nucleon interactions

In this study, the initial exciton numbers for the target nucleus 238U were calculated through a new method offered by Tel et al. (Ann. Nucl. Energy, 35, 220, 2008). Neutron-emission spectra produced by (n,xn) reactions on 238U nuclei have been calculated by using Hartree–Fock method with effective nucleon–nucleon Skyrme interactions with SKM∗ parameters. Pre-equilibrium nuclear reactions have been used to investigate the effect of initial exciton numbers on the nucleon emission spectra. Calculations have been made in the framework of the hybrid, equilibrium and GDH models using ALICE/ASH computer code. The initial exciton numbers calculated with the theoretical neutron and proton densities have been obtained with SKM∗ for the 238U(n,xn) reaction at 14.0 and 18.0MeV incident neutron energies. We also compared the geometry-dependent hybrid model (GDH), newly evaluated with the initial exciton number calculations of the neutron emission spectra of the 238U(n,xn) reaction. The obtained results are discussed and compared with the available experimental data and are shown to be in agreement with each other. All calculated results have been compared with experimental data from Experimental Nuclear Reaction Data (EXFOR).

Pre-equilibrium effects on proton, deuteron, and alpha induced reactions for the production of 72As as a PET imaging radioisotope

In this study, the production methods and the applications of 72As are reviewed with special attention to the feasibility of the cyclotron production of 72As. TALYS-1.4 and ALICE/ASH codes were employed to illustrate the formation of the 72As via natGe(p, xn)72As, 72,73,74Ge(p, xn)72As, 72Ge(d, 2n)72As, and 69Ga(α, n)72As reactions. Hybrid model and geometry dependent hybrid model were used in ALICE/ASH code to calculate the pre-equilibrium neutron-production cross sections. The excitation functions of the reactions were taken from the TENDL-2011 database and compared with the reported experimental measurement. The equilibrium and pre-equilibrium effects on the reactions were also discussed. An optimum energy range and the level of impurities for each reaction were determined. The 72As production yield was evaluated with concentration on the excitation function calculations and the stopping powers of the projectiles in the targets.

Alpha Production Cross Sections for Some Target Fusion Structural Materials up to 35 MeV

In the next century, because of the worldwide energy shortage, human life will badly be affected. Nuclear fusion energy is the remarkable solution to the rising energy challenges because it has the great potential for sustainability, economic and reliability. There have been many research and development studies to get energy from fusion. Moreover, the neutron induced reaction cross section data around 14–15 MeV are need to the design and development of nuclear fusion reactors. Thus, the working out the systematics of (n,α) reaction cross sections is very important and necessary for the definition of the excitation curves at around 14–15 MeV energy. In this study, neutron induced reaction cross sections for structural fusion materials such as Sc (Scandium), Co (Cobalt), Ni (Nickel), Cu (Copper), Y (Yttrium), Mo (Molybdenum), Zr (Zirconium) and Nb (Niobium) have been investigated for the (n,α) reactions. The new calculations on the excitation functions of 45Sc(n,a)42K, 59Co (n,a)56Mn, 62Ni(n,a)59Fe, 63Cu(n,a)60Co, 65Cu(n,a)62Co, 89Y(n,a)86Rb, 92Mo(n,a)89Zr, 98Mo(n,a)95Zr, 92Zr(n,a)89Sr, 94Zr(n,a)91Sr and 93Nb(n,a)90Y reactions have been carried out up to 35 MeV incident neutron energies. In these calculations, the pre-equilibrium and equilibrium effects 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. Additionaly, in the present work, the (n,α) 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 taken from EXFOR database.

Pre-equilibrium and equilibrium calculations of (n, p) reactions on 32S, 64Zn, 67Zn, 89Y, 90Zr and 153Eu targets used for production of 32P, 64Cu, 67Cu, 89Sr, 90Y and 153Sm therapeutic radionuclides

In this study, by using the pre-equilibrium and equilibrium reaction mechanisms, the cross-sections of (n, p) reactions on 32S, 64Zn, 67Zn, 89Y, 90Zr and 153Eu targets have been calculated. The excitation functions of (n, p) reactions on 32S, 64Zn, 67Zn, 89Y, 90Zr and 153Eu targets by using the hybrid model, the geometry dependent hybrid model and the exciton model of pre-equilibrium reaction mechanism at the energies in the range 1–20MeV have been investigated. To investigate the equilibrium effects, the Weisskopf–Ewing model is used. The proton emission spectra of (n, xp) reactions by 14.6, 14.8 and 14.8MeV neutron incident energies, respectively, on 32S, 89Y and 90Zr targets are also investigated using the same models. The obtained results have been discussed and compared with the experimental results.

Alpha Emission Spectra of 27Al, 50,52Cr, 55Mn, 54,56Fe, 58,60Ni Nucleus for Neutron Induced Reaction

The design of novel nuclear facilities, fusion as well as fission reactors, requires the knowledge of all properties of relevant materials, including the nuclear differential cross sections for a careful selection. The nuclear cross sections data for gas production via particle (neutron, proton, alpha, etc.) induced reactions are great importance in the domain in the fusion reactor technology, particularly in the calculation of nuclear transmutation rates, nuclear heating and radiation damage due to gas formation. In fusion reactor structures, a serious damage mechanism has been gas production in the metallic resulting from diverse nuclear reactions, mainly through (n, p) and (n, α), (n, d), (n, t). In the present study, by using equilibrium reaction mechanisms, the (n, xα) reaction alpha emission spectra for 27Al, 50,52Cr, 55Mn, 54,56Fe, 58,60Ni isotopes were investigated from 9 to 15 MeV incident neutron energy. The equilibrium results have been calculated by using the hybrid model, the geometry dependent hybrid model. Calculation results have been also compared with the available measurements in literature.

Deuteron Induced (d,p) and (d,2p) Nuclear Reactions up to 50 MeV

Many studies have shown that the nuclear reactions of charged particles with nuclei are very important in many fields of nuclear physics. The interactions of deuterons with nuclei have been especially the subject of common research in the history of nuclear physics. Moreover, the knowledge of cross section for deuteron-nucleus interactions are required for various application such as space applications, accelerator driven sub-critical systems, nuclear medicine, nuclear fission reactors and controlled thermonuclear fusion reactors. Particularly, the future of controlled thermonuclear fusion reactors is largely dependent on the nuclear reaction cross section data and the selection of structural fusion materials. Finally, the reaction cross section data of deuteron induced reactions on fusion structural materials are of great importance for development and design of both experimental and commercial fusion devices. In this work, reaction model calculations of the cross sections of deuteron induced reactions on structural fusion materials such as Al (Aluminium), Ti (Titanium), Cu (Copper), Ni (Nickel), Co (Cobalt), Fe (Iron), Zr (Zirconium), Hf (Hafnium) and Ta (Tantalum) have been investigated. The new calculations on the excitation functions of 27Al(d,2p)27Mg, 47Ti(d,2p)47Sc, 65Cu(d,2p)65Ni, 58Ni(d,2p)58Co, 59Co(d,2p)59Fe, 58Fe(d,p)59Fe, 96Zr(d,p)97Zr, 180Hf (d,p)181Hf and 181Ta(d,p)182Ta have been carried out for incident deuteron energies up to 50 MeV. In these calculations, the equilibrium and pre-equilibrium effects for (d,p) and (d,2p) reactions have been investigated. The equilibrium effects are calculated according to the Weisskopf-Ewing (WE) Model. The pre-equilibrium calculations involve the new evaluated the Geometry Dependent Hybrid Model (GDH) and Hybrid 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.

Calculations of (n,α) Cross Sections on Some Structural Fusion Materials for Fusion Reactor Technology

The knowledge of cross section for emission of light charged particles (p, d, t, andα) induced by fast neutrons on structural fusion materials has a critical importance on fusion reactors. The gas production arising from (n,p) and (n,α) 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,α) reaction cross section data are required to estimation of the radiation damage effects on structural fusion materials. Therefore, the cross section data for (n,α) 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 29Si,30Si,48Ti,50Ti,50Cr,54Cr,54Fe and 58Fe have been investigated. The new calculations on the excitation functions of 29Si (n,α) 26Mg,30Si (n,α) 27Mg,48Ti (n,α) 45Ca,50Ti (n,α) 47Ca,50Cr (n,α) 47Ti,54Cr (n,α) 51Ti,54Fe (n,α) 51Cr and 58Fe (n,α) 55Cr have been carried out for incident neutron energies up to 30 MeV. In these calculations, the pre-equilibrium and equilibrium effects for (n,α) 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,α) 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.

Calculations of Proton Emission Cross Sections in Deuteron Induced Reactions of Some Fusion Structural Materials

The 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 27 Al, 59 Co, 55 Mn, 50 Cr, 54 Cr, 64 Ni, 109 Ag, 184 W and 186 W 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 calcula- tions the program code ALICE/ASH was used. The cal- culated results are discussed and compared with the experimental data taken from the literature.

Alpha Induced Reaction Cross Section Calculations of Tantalum Nucleus

The fusion energy is attractive as an energy source because the fusion will not produce CO2 or SO2 and so fusion will not contribute to environmental problems, such as particulate pollution and excessive CO2 in the atmosphere. The fusion reaction does not produce radioactive nuclides and it is not self-sustaining, as is a fission reaction when a critical mass of fissionable material is assembled. Since the fusion reaction is easily and quickly quenched the primary sources of heat to drive such an accident are heat from radioactive decay and heat from chemical reactions. Both the magnitude and time dependence of the generation of heat from radioactive decay can be controlled by proper selection and design of materials. Tantalum is one of the candidate materials for the first wall of fusion reactors and for component parts of irradiation chambers. Accurate experimental cross-section data of alpha induced reactions on Tantalum are also of great importance for thermonuclear reaction rate determinations since the models used in the study of stellar nucleosynthesis are strongly dependent on these rates (Santos et al. in J Phys G 26:301, 2000). In this study, neutron-production cross sections for target nuclei 181Ta have been investigated up to 100 MeV alpha energy. The excitation functions for (α, xn) reactions (x = 1, 2, 3) have been calculated by pre-equilibrium reaction mechanism. And also neutron emission spectra for 181Ta (α, xn) reactions at 26.8 and 45.2 MeV have been calculated. The mean free path multiplier parameters has been investigated. The pre-equilibrium results have been calculated by using the hybrid model, the geometry dependent hybrid (GDH) model. Calculation results have been also compared with the available measurements in literature.

Deuteron-Induced Cross Section Calculations of Some Structural Fusion Materials

The development of fusion materials for the safety of fusion power systems and understanding nuclear properties is important. The reaction cross-section data have a critical importance on fusion reactors and development for fusion reactor technology. In this study, the theoretical cross sections of some structural fusion materials such as Cr, V, Fe, Ni, Zr and Ta in deuteron-induced reactions have been investigated. The new calculations on the excitation functions of 50Cr(d, α)48V, 51V(d, 2n)51Cr, 51V(d, 4n)49Cr, 54Fe(d, α)52Mn, 54Fe(d, n)55Co, 58Ni(d, α)56Co, 96Zr(d, n)97Nb, 96Zr(d, 2n)96Nb and 181Ta(d, 2n)181W reactions have been carried out up to 90 MeV incident deuteron energies. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve the geometry dependent hybrid model and hybrid model. Equilibrium effects have been calculated according to the Weisskopf–Ewing model. The ALICE/ASH computer code has been used in all calculations. The calculated results have been compared with the experimental data existing in EXFOR database and found to be in good agreement.

Nuclear model calculations on the production of 125,123Xe and 133,131,129,128Ba radioisotopes

In this study, production rates of 125,123Xe and 133,131,129,128Ba medical isotopes produced by 127I(p, 3n)125Xe, 127I(p, 5n)123Xe, 133Cs(p, n)133mg Ba, 133Cs(p, 3n)131mg Ba, 133Cs(p, 5n)129Ba, and 133Cs(p, 6n)128Ba reactions have been investigated up to 100 MeV incident proton energy. The preequilibrium calculations involve the hybrid model, the geometry-dependent hybrid model and the cascade exciton model. The calculated results are compared with the experimental data taken from the literature.

Cross sections of proton-induced reactions on natGd with special emphasis on the production possibilities of 152Tb and 155Tb

Cross sections and physical yields are presented for various Tb radionuclides formed in the bombardment of natGd with protons, from their respective thresholds up to 66MeV. New measurements are compared with theoretical predictions by means of the geometry-dependent hybrid (GDH) model as implemented in the code ALICE/ASH, as well as with previous literature experimental data, where available.Based on the agreement between the experimental results and the theoretical predictions, integral thick-target yields are also derived for the 152Gd(p,n) 152Tb, 155Gd(p,n) 155Tb and 155Gd(p,4n) 152Tb reactions forming the medically important 152gTb (SPECT) and 155Tb (PET) radionuclides.

Investigation of the neutron emission spectra of some deformed nuclei for (n,xn) reactions up to 26 MeV energy

In this study, neutron-emission spectra produced by (n,xn) reactions up to 26 MeV for some deformed target nuclei as 165Ho, 181Ta, 184W, 232Th and 238U have been investigated. Also, the mean free path parameter’s effect for (n,xn) neutron-emission spectra has been examined. In the calculations, pre-equilibrium neutron-emission spectra have been calculated by using new evaluated hybrid model and geometry dependent hybrid model, full exciton model and cascade exciton model. The reaction equilibrium component has been calculated by Weisskopf-Ewing model. The obtained results have been discussed and compared with the available experimental data and found agreement with each other.

Implementation of the Geometry Dependent Hybrid Model in TALYS

75-5865 Walua Rd. D423, Kailua-Kona, HI 96740, USA(Received 26 April 2010)The geometry dependent hybrid model (GDH) developed by M. Blann and supplied by themodels for the non-equilibrium cluster emission was implemented in the TALYS code. A number ofsubroutines from the ALICE and ALICE/ASH codes were introduced in TALYS after appropriatemodi cations. Common computations as those relating to binding energies, the optical model andothers are performed by means of TALYS. The value of the TALYS input variable \preeqmode"equal to 5 is reserved for the use of the GDH approach for the calculation of the pre-compoundenergy distributions of nucleon and light clusters. A comparison with calculations using the originalALICE and ALICE/ASH codes, on one hand, and experimental data, on the other hand, is given.The advantages of the implementation of the GDH model in the TALYS code are discussed.

Investigation of Some Stellar Iron Group Fusion Materials for (n, p) Reactions

In this study, we present the results of a careful analysis of cross sections of some important iron (Fe) group target elements (20 ≤ Z≤28) for astrophysical (n, p) reactions such as Si, Ca, Sc, Ti, V, Cr, Fe, Co and Ni used in neutron activation analysis have been investigated. The new calculations on the excitation functions of 28Si(n, p)28Al,29Si(n, p)29Al,42Ca(n, p)42K,45Sc(n, p)45Ca,46Ti(n, p)46Sc,51V(n, p)51Ti,52Cr(n, p)52V,53Cr(n, p)53V,54Fe(n, p)54Mn,57Fe(n, p)57Mn,59Co(n, p)59Fe,58Ni(n, p)58Co and60Ni(n, p)60Co reactions have been carried out up to 25 MeV incident neutron energy. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. Equilibrium effects are calculated according to the Weisskopf–Ewing model. The pre-equilibrium calculations involve the geometry dependent hybrid model, hybrid model and equilibrium model. Also in the present work, these reaction cross-sections have been calculated by using evaluated empirical formulas developed by Tel et al. at 14.7 MeV energy. The calculations are compared with existing experimental data as well as with evaluated data files (Experimental Nuclear Reaction Data (EXFOR). According to these calculations, we assume that these model calculations can be applied to some heavy elements, ejected into interstellar medium by dramatic supernova events.