Calculation of Cross-sections and Astrophysical S-Factors for <Superscript>62</Superscript>Ni(α,n) and <Superscript>62</Superscript>Ni(α,γ) Reactions of Structural Fusion Material Nickel

Nickel is an important element in fusion reactor technologies and astrophysical applications. Therefore, the knowledge of astrophysical S-factors and cross-sections on nickel isotopes is needed. In this work, the cross sections of the ⁶²Ni(α,n) and ⁶²Ni(α,γ) reactions have been calculated. The alpha capture cross sections was calculated up to 10 MeV. In these theoretical calculations, the TALYS 1.6 and NON-SMOKER codes were used. Also for the ⁶²Ni(α,n) and ⁶²Ni(α,γ) reactions, we calculated the astrophysical S-factors that determine the probability of reaction in low energies. Results of our calculations were checked to the experimental data obtained from EXFOR database.     

Experimental determination of <Superscript>80,82,83</Superscript>Kr(α, <Emphasis Type="Italic">xn</Emphasis>)<Superscript>82</Superscript>Sr cross sections for reaction threshold to 60 MeV α-particles

The activation method has been used to determine the experimental cross sections of the nuclear reactions ⁸⁰Kr(α, 2n)⁸²Sr, ⁸²Kr(α, 4n)⁸²Sr, and ⁸³Kr(α, 5n)⁸²Sr for α-particle energies from the reaction threshold to E_α = 60 MeV on targets which are highly enriched with krypton isotopes. The structural and geometric parameters are established for a “thick” cascade target with krypton isotopes, which gives maximum ⁸²Sr yield for E_α ≤ 60 MeV. The ⁸²Sr yield in the indicated target for initial energy E_α = 60 MeV is estimated to be 3.4·10⁶ Bq/(μA·h), which gives a basis for commercial applications of this isotope in medium-energy accelerators.     

<Superscript>246–248</Superscript>Cm Neutron fission cross sections and resonance integrals

The fission cross sections of ^246–248Cm nuclei for neutron energies 0.1 eV–20 keV have been measured using an SVZ-100 lead moderation time neutron spectrometer at the Institute of Nuclear Research of the Russian Academy of Sciences. The fission resonance integrals have been calculated. The results are compared with the existing data and recommended evaluations.     

Cosmogenic <Superscript>7</Superscript>Be fallout near Samarkand in 2002–2009

⁷Be fallout measurements performed around Samarkand in 2002–2009 are presented. The calendar period included in this research covers the ascending part of the 23rd solar activity cycle; this part of the cycle corresponded to a decrease of the monthly average value of the Wolf number from 60 to <5. The linear correlation observed between the fallout and amount of wet precipitation indicates that the latter plays the main role in the removal of ⁷Be from the troposphere. The average seasonal ⁷Be fallout is 223 ± 46 Bq/m² during winter, 324 ± 66 Bq/m² during spring, 75 ± 29 Bq/m² during summer, and 189 ± 43 Bq/m² during fall. These measurements make it possible to evaluate the contribution of precipitation in the form of dust and dew to the total ⁷Be fallout during the summer. The correlation between the solar radiation and ⁷Be fallout is confirmed.     

Comparison of Level Density Models for the <Superscript>60,61,62,64</Superscript>Ni(p,n) Reactions of Structural Fusion Material Nickel from Threshold to 30 MeV

The knowledge of level density for reaction cross-section calculations are needed for various applications such as fission and fusion reactor design, accelerator driven sub-critical systems, nuclear medicine, neutron capture and astrophysics. In this study, the excitation functions for (p, n) reactions from reaction threshold to 30 MeV proton incident energy on ⁶⁰Ni, ⁶¹Ni, ⁶²Ni and ⁶⁴Ni isotopes were calculated using TALYS 1.6 nuclear code involving the level density models. This is of importance to the validation of nuclear model approaches with increased predictive power. There are several models of level density that can be used to predict cross-section. In this work, the (p, n) cross-sections would be calculated using three different model of level density, such as constant temperature model, back-shifted fermi gas model and generalized superfluid model on ^60,61,62,64Ni reactions. The (p, n) reaction cross-section calculations for ^60,61,62,64Ni target nuclei were compared with each other and the experimental nuclear reaction data obtained from EXFOR database.     

Evaluation and Calculation of Activation Cross Sections for ~(151,153)Eu(n,2n), (n,3n), (n,γ) and (n,x) Reactions below 20 MeV

Eu is a rare-earth element. Its activation cross section is important for nuclear science and technology applications. However, there are some discrepancies in several evaluated nuclear data libraries. The cross section for ~(151,153)Eu(n,2n) reactions were one of the Coordinate Research Programs of IAEA on activation cross sections     

Evaluation and Calculation of Activation Cross Sections for ~(158,159)Tb(n,2n), (n,3n), (n,γ) and (n,x) Reactions Below 20 MeV

Introduction ~(159)Tb is a rare-earth element. Its activation cross section is a good indicator for nuclear science and technology applications. However, the evaluated data are very scarce in several nuclear data libraries. The cross section for ~(159)Tb(n,2n)~(158)Tb reaction was one of the Coordinate Research Program of IAEA on activation cross     

Evaluation and Calculation of Activation Cross Sections for ~(169)Tm(n,2n), (n,3n), (n,γ) and (n,x) Reactions Below 20 MeV

Introduction ~(169)Tm is a rare-earth element. Its activation cross sections are a good indicator for nuclear science and technology applications. However, there are no evaluated data in several nuclear data libraries. The activation cross sections for ~(169)Tm(n,2n), (n,3n), (n,γ) and some emission charged particle (n,x) reactions below 20 MeV were evaluated and calculated on the basis of experimental and theoretical data.     

Pre-Equilibrium <Superscript>3</Superscript>He-Emission Spectra at 62 MeV Proton Incident Energy

In this study, the ³He-emission cross sections for ²⁷Al, ^54,56Fe, ¹⁹⁷Au, ²⁰⁸Pb and ²⁰⁹Bi target nuclei have been calculated at 62 MeV proton energy. In these calculations, the pre-equilibrium effects have been investigated. The pre-equilibrium calculations involve the geometry dependent hybrid model and hybrid model. A comparison with theoretical calculations (ALICE/ASH) has been performed and the empirical formulas for the ³He- emission cross sections produced at 62 MeV proton energy have been derived.     

Neutron Emission Spectra of <Superscript>104,105,106,108,110</Superscript>Pd Isotopes for (p,xn) Reactions at 21.6 MeV Proton Incident Energy

Palladium, which is a rare and lustrous silvery-white color from precious metals, plays important role in fusion–fission reactions and different fields of nuclear technology. In addition, it is used for not only cold fusion experiments but also separation of hydrogen isotopes researches for fusion reactors. In this study, neutron-emission spectra produced by (p,xn) reactions for structural fusion material ^{104,105,106,108,110}Pd isotopes have been investigated by a proton beam at 21.6 MeV. Moreover, multiple pre-equilibrium mean free paths constant from internal transition, and the pre-equilibrium and equilibrium level density parameters have been analyzed for some (p,xn) neutron-emission spectra calculated. New evaluated hybrid model and geometry dependent hybrid model, full exciton model and cascade exciton model were used to calculate the pre-equilibrium neutron-emission spectra. For the reaction equilibrium component, Weisskopf–Ewing model calculations were preferred. The obtained results have been discussed and compared with the available experimental data and found agreement with each other.     

A study on the excitation functions of ~(60,62)Ni(α,n),~(60,61)Ni(α,2n),~(58,64)Ni(α,p),~(nat)Ni(α,x) reactions

The prediction of nuclear cross-section data is crucial, especially in the absence of experimental data or in the difficulty of these experimental data. Nickel(Ni) is an important material in fusion and fission reactor technologies, the production of radionuclides in nuclear medicine,and many other fields. In this study, the excitation functions for~(60,62) Ni(a,n),~(60,61) Ni(a,2 n),~(58,64) Ni(a,p), and ~(nat)Ni(a,x) reactions have been investigated by using preequilibrium reaction models. The calculations of the excitation functions for the reactions are used with the geometry-dependent hybrid model in ALICE/ASH code and the two-component exciton model in TALYS 1.8 code. The obtained results are compared to each other, and the experimental data are taken from the EXFOR database.     

Parameters of <Emphasis Type="Italic">s</Emphasis>-resonances in <Superscript>246–248</Superscript>Cm fission cross sections

The fission cross sections of ²⁴⁶Cm, ²⁴⁷Cm, and ²⁴⁸Cm isotopes measured with an SVZ-100 spectrometer, based on neutron moderation in lead, at the Institute of Nuclear Research of the Russian Academy of Sciences are analyzed. The area of the resolved resonances is calculated, and their neutron and fission widths are determined. The results are compared with existing data and recommended evaluations.     

Investigation of Orbits and Stability of Negative Ions of Hydrogen (H<Superscript>−</Superscript>) in Simulated Main Magnetic Field of AVF Cyclotrons

This paper describes equilibrium orbit and stability of negative hydrogen ions (H⁻) on a four sector of tight design giving 30 MeV protons. We simulated radial and vertical changes of main magnetic field of Cyclone-30 by multi degree and Fourier functions. Based on measured main magnetic field by IBA (Ion Beam Application), we calculated coefficients of these functions and investigate equilibrium orbit and stability includes Betetatron frequency, radial and vertical motion and etc. Advanced graphical tools of MATLAB give good visualization features to created models. The simulation results are in good agreement with experimental data.     

A Study on <Superscript>8–18</Superscript>Be Isotopes Used on Neutron Multiplier in Reactor Design

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 ^8–18Be 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.     

~(197)Au(n,2n),~(197)Au(n,3n)反应截面测量

本文在中子能量E_n=12～18兆电子伏能区用活化法测量了~(197)Au(n,2n),(n,3n)的反应截面。在E_n=14.6±0.3兆电子伏处以~(27)Al(n,α)~(24)Na反应截面为标准(117.5±3.9毫靶)给出(n,2n)截面为2160±95毫靶。以(n,2n)截面为标准给出(n,3n)截面为636±47毫靶(8.23±O.28兆电子伏)。本文对国外发表的数据作了比较,井给出了推荐曲线。     

Calculation of cross sections for metastable state production in the (n, γ), (n,n′), (n, 2n) and (n, 3n) reactions of 93Nb

Toward the revision of ⁹³Nb data in the Japanese Evaluated Nuclear Data Library JENDL-4.0, we calculated cross sections for metastable state production (MSP) in the (n, γ), (n, n′), (n, 2n) and (n, 3n) reactions in the incident energy (E_n) range from 7 keV to 20 MeV. The cross sections were evaluated using nuclear reaction models such as the spherical optical model, the multi-step statistical model, preequilibrium models, and the distorted-wave Born approximation (DWBA). By adjusting parameters of nuclear level densities, we could obtain the MSP cross sections which are almost consistent with the experimental data.     

Measurements of activation cross sections for Lu(n, α)Tm,Lu(n, α)Tm and Lu(n, p)Yb reactions induced by neutrons around 14 MeV

The cross sections for the ¹⁷⁵Lu(n, α)¹⁷²Tm, ¹⁷⁶Lu(n, α)¹⁷³Tm and ¹⁷⁵Lu(n, p)^175m+gYb reactions have been measured in the neutron energy range of 13.5–14.8 MeV using the activation technique. The first data for ¹⁷⁵Lu(n, α)¹⁷²Tm reaction cross sections are presented. In our experiment, the fast neutrons were produced via the ³H(d, n)⁴He reaction on K-400 Neutron Generator at Chinese Academy of Engineering Physics (CAEP). Induced gamma activities were measured by a high-resolution (1.69 keV at 1332 keV for ⁶⁰Co) gamma-ray spectrometer with high-purity germanium (HPGe) detector. Measurements were corrected for gamma-ray attenuations, random coincidence (pile-up), dead time and fluctuation of neutron flux. The neutron fluences were determined by the cross section of ⁹³Nb(n, 2n)^92mNb or ²⁷Al(n, α)²⁴Na reactions. The neutron energy in the measurement was by the cross section ratios of ⁹⁰Zr(n, 2n)^89m+gZr and ⁹³Nb(n, 2n)^92mNb reactions. The results were discussed and compared with experimental data found in the literature and with results of published empirical formulae.     

Semi-empirical systematics for the cross-sections of the reactions (n,α), (n,p) and (n,2n) at 14.5 MeV neutrons on the basis of experimental data measured by Lanzhou University

Three new semi-empirical formulae for the calculation of the (n,α), (n,p) and (n,2n) cross-sections at neutron energy 14.5 MeV were obtained on the basis of experimental data measured by Lanzhou University. Derived from the statistical model with consideration of the Q-value dependence, the new formulae include three, three and four parameters for (n,α), (n,p) and (n,2n) reactions, respectively. The obtained relations are compared with other recently proposed systematics based on the statistical model as well as on the asymmetry parameter dependence.     

Evaluation of Activation Cross Sections for (n,α) and (n,n'α) Reactions on ~(63, 65, Nat)Cu

Introduction Copper is a very important structure material in nuclear fusion engineering. The neutron activation cross section are very useful in fusion research and other applications such as radiation safety, environmental, material damage and neutron dosimetry. More efforts are required to identify and resolve the differences and discrepancies in the existing activation cross sections from different laboratories. The natural copper consists of two stable isotopes, i.e. ~(63)Cu, ~(65)Cu. Their abundaces and threshold energies are given in Table 1.     

Systematics of (n,2n) and (n,3n) Reaction Cross Sections

The systematics of(n,2n)and(n,3n)cross sections have been studied bymeans of the evaporation model including preequilibrium emission.A set of empi-rical parameters has been extracted on the bases of analysing and fitting the