Effect of the structure of neutron-rich <Superscript>8</Superscript>Li and <Superscript>9</Superscript>Li isotopes on the characteristics of proton elastic scattering

The differential cross sections of proton elastic scattering from ⁸Li and ⁹Li nuclei in inverse kinematics have been calculated. The cross sections were determined within the Glauber diffraction theory with the wave functions of nuclei in the three-particle α-t-n, α-t-2n, and ⁷Li-n-n models. Comparison with the existing experimental data for E = 700 and 60 MeV/nucleon made it possible to draw a conclusion about the quality of the wave functions and the adequacy of the potentials used for their calculations.     

Proton optical potentials at intermediate energies from Brueckner theory

We have analysed proton scattering cross sections and polarisations from ⁴⁰Ca and ²⁰⁸Pb at intermediate energies using optical potentials calculated from Brueckner theory with internucleon potentials and ground state densities both different from those used previously. We show that the calculated results are very sensitive to the assumed densities and that agreement with experiment is only obtained using phenomenological densities and is not obtained using shell-model densities. We are not able to obtain agreement with the experimental data with a particular soft-core potential, Urbana V-14.     

Nucleon elastic scattering from 40Ca between 11 and 48 MeV

Differential cross sections for the elastic scattering of neutrons from ⁴⁰Ca have been measured in the 19–26 MeV region. The neutron elastic scattering data, previous neutron measurements and additional proton elastic scattering data are analyzed using three different approaches to the optical model potential: Woods-Saxon parameterization, model independent analysis and microscopic calculations. The difference between the phenomenological neutron and proton real potentials is studied in terms of Coulomb effects, nuclear polarization and charge symmetry breaking in the nuclear mean field.     

Cross sections of spallation residues produced in 1A GeV 208Pb on proton reactions

Spallation residues produced in 1 GeV per nucleon 208Pb on proton reactions have been studied using the Fragment Separator facility at GSI. Isotopic production cross sections of elements from 61Pm to 82Pb have been measured down to 0.1 mb with a high accuracy. The recoil kinetic energies of the produced fragments were also determined. The obtained cross sections agree with most of the few existing gamma-spectroscopic data. The data are compared with different intranuclear-cascade and evaporation-fission models. Drastic deviations were found for a standard code used in technical applications.     

An analysis of available absolute total cross section data for noble gas systems

The most important literature data on absolute total cross sections for noble gas systems have been surveyed. A comparison has been made with total cross sections calculated from various interatomic potentials proposed in the literature and with the total cross sections deduced from the long range part of the potential theoretically derived by Tang et al. for the noble gas systems.     

Inclusive stripping reaction in the theory of deuteron-nucleus diffraction interaction and the spectator model

The applicability of the spectator model to reactions with weakly bound nuclei is considered by the example of the inclusive proton stripping reaction at deuteron-nucleus diffraction interaction. Analytical methods are used to calculate the integral and differential (with respect to the neutron longitudinal momenta) stripping cross sections. An actual relation is obtained for the effective potentials describing the absorption of each nucleon by the target nucleus in different configuration space regions, which contribute to the stripping cross section.     

核子-核子碰撞截面的参数化公式

核子-核子碰撞截面(σ_NN)是描述原子核反应模型中的重要物理量。 核子-核子碰撞截面包括质子-质子碰撞截面（σ_pp）、中子-中子碰撞截面（σ_NN）和中子 质子碰撞截面（σ_np）, 它们随着核子能量与核物质密度的改变而变化。人们在目前研究中提出了多种核子-核子碰撞截面关于能量和核物质密度的参数化公式,通过计算12C+12C的完全反应截面,比较了不同入射能量下使用各种核子-核子碰撞截面参数化公式对12C完全反应截面的影响。 The nucleus-nucleus cross sections(σ_NN) include the proton-proton cross section, neutron-neutron cross section, and neutron-proton cross section. σ_NN change with the variations of the incident energies and the densities. Some parameterizations of σ_NNas a function of incident energy and density have been proposed in the theoretical and experimental study of nuclear reactions. Through the calculation of reaction cross sections of 12C+12C at different energies, the effect of different σ_NN parameterizations in the reaction cross sections of 12 are studied.      

Proton and triton momentum distributions from4He fragmentation at relativistic energies

The 0° differential cross sections of the¹²C(⁴He,p) and¹²C(⁴He,t) reactions have been measured at beam momenta of 4.52 and 2.69 GeV/c/nucleon, respectively. The proton and triton momentum distributions in⁴He are extracted from the cross sections using a relativistic impulse approximation. Some theoretical models based on realisticN-N potentials are examined for our data.     

An empirical fit to estimated neutron emission cross sections from proton induced reactions

Neutron emission cross section for various elements from⁹Be to²⁰⁹Bi have been calculated using the hybrid model code ALICE-91 for proton induced reactions in the energy range 25 MeV to 105 Me V. An empirical expression relating neutron emission cross section to target mass number and incident proton energy has been obtained. The simple expression reduces the computation time significantly. The trend in the variation of neutron emission cross sections with respect to the target mass number and incident proton energy has been discussed within the framework of the model used.     

Fission of232Th induced by 4–11 MeV protons

The excitation function for the²³²Th(p,f) reaction has been determined in the energy range from 4 to 11 MeV. A discrepancy existing in the literature is resolved. The mass yield distribution has been studied at 8 MeV proton energy and the peak-to-valley ratio has been determined to be 9.2. The fission data, together with evaporation residue data from an earlier experiment, are understood rather well within the framework of a statistical decay model which derives its parameters from independent data. The absorption cross sections for protons in the vicinity of and below the Coulomb barrier are also discussed and confronted with optical model predictions using published global proton potentials.     

Measurement of double-differential (n,xp) cross sections of natural nickel in 14.6 MeV neutron energy

The energy spectra and angular distributions of proton emission in the reaction of ^natNi(n,xp) at neutron energy 14.6 MeV have been measured by the USTC multitelescope system. The double-differential cross sections of 16 reaction angles from 25° to 164.5° have been obtained in this measurement. The statistical error can be reduced because of the thicktarget used. The angular distributions show a slightly energy-dependent forward-backward asymmetry. The angle-integrated proton spectrum is compared with ENDF/B-VI evaluation and Grimes' result. The total p-emission cross section is in fair agreement with prediction and evaluation.     

Elastic and inelastic scattering of nucleons from 16O

Measurements of differential elastic and inelastic cross sections for neutron scattering from ¹⁶O at incident energies 18 to 26 MeV are presented. In addition to cross sections for neutron scattering differential cross sections for proton scattering up to 66 MeV are described in terms of phenomenological optical model potentials. At 24.5 MeV incident energy inelastic scattering up to 11.5 MeV excitation was measured. The elastic and inelastic compound nucleus contributions were examined. Direct inelastic scattering from the normal parity states was calculated using the DWBA and coupled-channel formalisms. The inelastic scattering cross section from non-normal parity state 2⁻ was calculated using the coupled-channel formalism via multi-step processes. Cross sections due to inelastic scattering from some of the states, which are thought to be members of an excited state rotational band were calculated using both vibrational and rotational approaches and were compared.     

Fusion cross sections for 10,11B+12C at sub-Coulomb energies

Total fusion cross sections for the ¹⁰B + ¹²C and ¹¹B + ¹²C reactions have been determined over a 5 MeV (c.m.) energy range extending to ≈ 3 MeV below the Coulomb barrier. Absolute γ-ray yields for specific transitions in the de-excitation of the heavy products following compound nucleus decay were measured using a Ge(Li) detector. Statistical model calculations of the decay modes of the compound nucleus have been used to deduce, from the γ-ray data, cross sections for single proton, neutron and α-particle emission, and to determine total cross sections for compound nucleus formation. No evidence has been found for sub-Coulomb resonances in either reaction. The total reaction cross sections are compared with optical model calculations using different parameter sets and the observed trend in the very low energy cross sections is discussed relative to other reactions in the same mass region.     

Elastic backscattering cross sections of protons on oxygen

Absolute values of elastic scattering cross section of protons in the energy region 600–2,000 keV have been measured on oxygen for scattering angles between 110 and 160°. The method applied in the present work is advantageous in regard to determine absolute cross sections, since quantities such as proton particle fluence and detection geometry can be neglected. The results show that the measured cross sections are considerable higher than Rutherford cross sections for proton energies close to 2,000 keV. No resonances are observed in the energy region studied.     

MASS ATTENUATION COEFFICIENTS FOR ELEMENTS MEASURED WITH CHARACTERISTIC X-RAYS FROM TARGETS EXCITED BY ENERGETIC PROTON

The characteristic X-rays from elemental or compound targets excited by energetic proton are quasi-monochromatic X-ray sources. The advantages of high line/ background ratio, controllable intensity as well as many available energies, make them suitable for applications in many important fields. The total mass attenuation cross sections of yttrium have been systematically measured by using this kind of X-ray source. The accuracy of experimental data has been improved to ±1%, which is much better than that of earlier results. The contributions of the coherent and incoherent scattering crees sections have been calcu-lated in accordance with the present experimental condition. And the total photoelectric cross sections have been obtained by subtracting the scattering cross section from the measured total cross sections. The com-parisons of our experimental results with the available data of earlier investigations as well as with the theo-retical calculations have been presented and discussed.     

Measurement of (n,p) cross sections on isotopes of Cd,Sn and Te for 14 MeV neutrons

For several isotopes of Cd, Sn and Te, cross sections for the (n, p) process have been measured by activation relative to ²⁷Al(n, α)²⁴Na. As target materials, natural Cd, Sn and TeO₂ of high purity have been used. Measurements were carried out by γ-detection using a Ge(Li) detector. For measuring short-lived activities, a pneumatic tube system was used. The neutron energy was 14.6±0.2 MeV for all activations. The results obtained for the total (n, p) cross sections show decreasing values with increasing number of neutrons for a given proton number. This trend obviously follows the behaviour of the difference of the proton and neutron separation energies, determining the competition between proton and neutron emission.     

Comparison between global phenomenological and microscopic optical potentials for proton as projectile below 100 MeV

For 112 target nuclei (52 elements) with proton as projectile, we calculate the reaction cross sections and elastic scattering angular distributions, as well as the X2 values for 16 kinds of proton optical model potentials: two sets of phenomenological global optical potentials and the microscopic optical potentials proposed by Shen et al for 14 sets of Skyrme force parameters: GSI-6, SBJS, SKM, SGI-Ⅱ, SKa-b, SG01-Ⅱ.We find that for obtaining the proton microscopic optical potential based on the nuclear matter approach with Skyrme force, SGI, SKa and SKb are the three sets of optimal Skyrme force parameters.     

A theoretical study of the non-adiabatic charge transfer process Ar2+ (3 P) + He(1 S) → Ar+(2 P) + He+(2 S)

CI calculation with a large basis have been used to calculate the two lowest ³Π adiabatic potential energy curves for the title reaction. These potentials have been transformed to diabatic potentials by employing a recipe based on the CI coefficients. Quantum mechanical close coupling calculations in the diabatic basis have produced total and differential cross sections which are in good agreement with experimental data. Full quantum mechanical and Landau-Zener calculations of the total cross section are in fair agreement with recent experimental measures and by small changes to the diabatic potentials can be brought into essentially exact agreement.     

K-shell ionization by protons for Cr,Cu, In and by alpha-particles for Cr,Cu

K-shell ionization cross sections have been determined for Cr, Cu and In at proton bombardment in the energy region from 0.9 to 2.5 MeV. The same cross sections were determined for Cr and Cu at alpha bombardment in the 0.9–4.0 MeV region. The experimental results are compared with five different theoretical calculations.