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     

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.     

Empirical Formulas for 14-MeV (n,p) and (n, α) Cross Sections

Empirical formulas for the 14 MeV (n, p) and (n, α)cross sections given by Levkovskii were modified separately In three ranges of mass number, in each of which, coefficients modifying Levkovskii's formulas were determined by least-squares fitting to experimental cross sections. The resulting modified formulas yielded cross sections representing markedly smaller chi-square deviations from experimental values, and moreover gathered closer to unity, compared with calculation using Levkovskii's original formulas.     

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.     

Cross Section Measurements for ~(111)Cd(n,p)~(111m)Ag,~(106)Cd(n,2n)~(105)Cd,~(110)Cd(n,2n)~(109)Cd,~(116)Cd(n,2n)~(115m)Cd and ~(116)Cd(n,2n)~(115g)Cd Reactions

Activation cross sections for cadmium were measured in the neutron energy range from 13.40 MeV to 14.80 MeV using the T(d,n)~4He reaction as neutron source. The cross sections of ~(27)Al(n,α)~(24)Na reaction is used as standard one.     

(n,2n)和(n,3n)激发函数的计算

本文从入射中子能量为E=14MeV的σ_(n,2n)实验值出发,应用复合核模型,计算了十三种无分支比复合核衰变的非裂变重核(A>169)的(n,2n)、(n,3n)激发函数。与实验激发曲线比较,讨论了计算的合理性和可靠性。     

Evaluation of Activation Cross Sections for (n,2n) and (n,γ) Reactions on ~(63, 65, Nat)Cu

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. The reaction Q-Values and abundances are listed in Table 1.     

The Systematics Research on (p, n) and (p,2n) Reaction Excitation Functions

On the basis of Planck formula of black body radiation and experimental excitation functions of (p,n) and (p,2n) reactions, an empirical systematics formula with two parameters is presented, which can describe experimental data of (p,n) and (p,2n) reactions well for incident proton energies from threshold to 150 MeV, target masses from 30 to 243.     

Evaluation of Activation Cross Sections for (n,p) and (n,n′p) 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     

Systematics of H(n,n) Cross Sections and Angular Distributions

Nucleon-nucleon interaction is the most basic one in nuclear physics. The data of nucleon-nucleon elastic scattering cross sections and angular distributions are very useful in the study of nuclear many-body problems and nuclear reactions as well as the nuclear engineering design. The neutron-hydrogen nuclear data below 30 MeV have been studied. In order to meet the needs in higher energy region, a systematics of neutron-hydrogen elastic scattering cross sections and angular distributions in energy region 2～150 MeV is given in this paper.     

~(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。     

The Systematic Calculations of(n,2n) and (n,3n)Reaction Cross Sections for Medium-Heavy Nuclides at 14.5 MeV

The(n,2n)and(n,3n)reaction processes have been studied by mechanism     

Activation Cross Sections for (n,p) and (n, α) Reactions on Nd,Sm, Yb and Lu at 14.6 MeV

Activation cross sections for the (n, p) and (n, α) reactions of Nd, Sm, Yb and Lu have been measured at 14.6 MeV by using a Ge(Li) γ-ray detector. The following cross sections (in millibarns) have been obtained: ¹⁵⁰Sm(n, p) ¹⁵⁰Pm, 7.19±1.01; ¹⁷³Yb(n, p) ¹⁷³Tm, 13.5±2.8; ¹⁷⁵Lu(n, p) ¹⁷⁵Yb, 18.5±2.2;¹⁴⁶Nd(n,α) ¹⁴³Ce, 4.42±0.47; ¹⁵²Sm(n, α) ¹⁴⁹Nd, 2.81±0.42; 174Yb(n, α)¹⁷¹Er, 1.22±0.23 and ¹⁷⁶Lu(n, α)¹⁷³Tm, 2.30±0.57. The results are compared with predictions based on the evaporation, the pre-equilibrium and other models. The present experimental (n, p) cross sections agree fairly well with the pre-equilibrium model predictions. A comparison made between the experimental (n, α) cross sections and the predictions of the pre-equilibrium model suggests the existence of a mechanism of pre-equilibrium emission in the (n, α) reaction in this mass region.     

Evaluation of Cross Sections for ~(197)Au(n,3n) and ~(197)Au(n,4n) Reactions from Threshold to 50 MeV

The measured data of cross sections for ~(197)Au(n,3n) and ~(197)Au(n,4n) reactions were collected and analysed. The theoretical calculations of above mentioned reactions were carried out to predict the data in higher energy region. The sets of cross sections for ~(197)Au(n,3n) and ~(197)Au(n,4n) reactions from threshold to 50 MeV were recommended on the basis of the experimental and calculated data.     

实验测定~(116)Cd(n,2n)和~(115)In(n,p)反应截面

一、引言由于对~_(116)Cd(n,2n)反应的截面测量数据分歧较大,而关于~(115)In(n,p)反应,文献中也只报导了该反应的总截面,对亚稳态和基态的截面国内外报导得均很少,因此,我们通过实验来测定~(116)Cd(n,2n)和~(115)In(n,p)反应中产生的~(115m,g)Cd的截面和它们     

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.     

Analysis of Total (n,p) and (n, α) Cross Sections at 14 MeV with Pre-Equilibrium Model

Corrosion of Type 304 stainless steel by molten Cs₂O₃-CsO₂ has been investigated at 690 and 800°C. The Cs₂O₃-CsO₂ mixture was selected as corroding agent in order to clarify the corrosion behavior of stainless steel at a considerably high oxygen potential. At the initial stage a uniform Fe₃O₄ layer is formed and is then removed. After the removal of the oxide film intergranular penetration proceeds into the alloy substrate. Chromium-containing oxides are formed as corrosion products at the grain boundaries. After the grain boundary penetration has continued for a while, a Cr-depleted surface alloy layer is formed, which blocks further progressing of the intergranular penetration. Then, this Cr-depleted layer is detached, inducing the restart of the intergranular penetration. Compared to the reported intergranular penetration rates of stainless steel due to Cs₂O₃-Cs₂O₂, those due to Cs₂O₃-CsO₂ obtained in this study were generally lower, and changed in a more complicated fashion with time.