Charge exchange collisions of H<Superscript>+</Superscript>/D<Superscript>+</Superscript> ions with alkaline Earth atoms (Ca,Mg)

The Classical Trajectory Monte Carlo (CTMC) Method has been used to calculate the differential, partial and total single electron capture cross sections for the collision of H⁺/D⁺ with Ca and Mg atoms in the energy range of 1–100 keV. The differential cross sections at angles near the diffraction limit (<0.1^○) in both systems show a forward peak followed by an asymptotic fall at higher angles. Total and partial capture cross sections are found to be in good agreement with the experimental observations. Oscillations in the partial capture cross sections have been explained due to the swapping of the field electron. Isotope effect in the electron transfer is reported to be negligible.     

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.     

Measurements of the total π-He and p-He cross sections and the slopes of the forward diffraction peak at energies from 50 to 300 GeV

Differential cross sections for elastic scattering of pions and protons on helium have been measured at incident momenta ranging from 50 to 300 GeV/c in the t-range 0.008 < | < | < 0.05 (GeV/c)². Both recoil α-particles and forward particles were detected in this experiment. The experimental method provided an absolute normalization of the cross sections with an estimated precision of 1%. From the analysis of the data, the diffraction slope parameters and total cross sections have been obtained. The results are compared with Glauber model calculations.     

Nuclear and Coulomb interactions in coherent fragmentation of relativistic nuclei in a photoemulsion

The role of the nuclear and Coulomb interactions in coherent fragmentation of relativistic nuclei is discussed with the cluster-model analysis of the experimental data on the fragmentation of ⁷Li (P = 3A GeV/c) via the ³H + ⁴He channel in photoemulsion used as an example. The calculated electromagnetic contribution of ～10% to the cross section is not in conflict with the photoemulsion data and the upper estimate of ～40% derived from the earlier measurements of total cross sections for fragmentation of light nuclei using the counter technique. The observed irregularities in the differential cross section for ⁷Li fragmentation with a separated Coulomb peak at a very small momentum transfer Q are ascribed to the overlap of nuclear diffraction patterns arising from light (C, N, O) and heavy (Ag, Br) photoemulsion nuclei. The predicted diffraction cross sections in the inelastic channel drastically differ from the usual shape of nuclear diffraction in an elastic channel. For pure targets, they have a shape of oscillations with a few peaks of comparable intensity and show strong dependence on the form of the surface nuclear density and radii of the intranuclear cluster and target nucleus. The probability for two-body clustering in ⁷Li is estimated at about 0.7.     

The antiproton-nucleus elastic scattering and the alpha-cluster model with dispersion

The elastic scattering differential cross sections of intermediate energy antiprotons on¹²C and¹⁶O nuclei and the elastic scattering polarization observables of antiprotons on these nuclei have been calculated on the basis of theα-cluster model with dispersion and multiple diffraction theory. The results of these calculations are compared with the experimental data.     

Radiative capture of deuterons in Ba and Au

¹³⁸Ba(d,γ)¹⁴⁰La and¹⁹⁷Au(d,γ)^199mHg cross sections were measured for deuteron energies ranging from 5 to 26 MeV. A survey of existing experimental (p,γ), (d,γ) and (α,γ) cross sections is given. A comparison of all the experimental data with calculated compound nucleus cross sections is performed. An increase in the ratio of experimental cross sections and calculated compound nuclear cross sections with increasing mass numberA is observed for all capture processes.     

Microscopic description of diffractive deuteron breakup by <Superscript>3</Superscript>He nuclei

A microscopic formalism for describing observed cross sections for deuteron breakup by threenucleon nuclei was developed on the basis of the diffraction nuclear model. A general formula that describes the amplitude for the reaction ²H(³He, ³Hep)n and which involves only one adjustable parameter was obtained by using expansions of the integrands involved in terms of a Gaussian basis. This formula was used to analyze experimental data on the exclusive cross sections for deuteron breakup by ³He nuclei at the projectile energy of 89.4MeV. The importance of employing, in calculations, a deuteron wave function that has a correct asymptotic behavior at large nucleon–nucleon distances was demonstrated.     

Deformation effects in heavy-ion scattering

Many experiments on the scattering of heavy ions confirm that the elastic cross sections display characteristics of Fresnel diffraction. Recent experiments on the scattering of very heavy ions, however, show marked deviations from the expected Fresnel shapes and an analysis of these experiments using the “quarter-point-recipe” of the Fresnel cross section yields a larger radius for ²⁰⁸Pb than for ²³²Th. It is shown that the deviations may be described in terms of the ground state deformations of the nuclei involved. Taking the deformations into account removes the above anomaly in the radii. The actual fit to the experimental cross sections is not very good and suggests that the real part of the nuclear potential may have an appreciable effect on the orbits of nuclei which are elastically scattered below the Coulomb barrier.     

A comparison of absolute cross sections for electro- and photo-induced reactions

Absolute cross sections for electron and positron induced reactions on¹²C,⁶³Cu and¹⁰⁷Ag are compared with cross sections for the corresponding photo-induced reactions in order to test DWBA calculations of the virtual photon spectra. A good agreement is found between the experimental cross sections for the electrodisintegration and those calculated with DWBA spectra and photonuclear cross sections.     

Structure of neutron-rich Isotopes <Superscript>8</Superscript>Li and <Superscript>9</Superscript>Li and allowance for it in elastic scattering

The differential cross sections for elastic proton scattering on the unstable neutron-rich nuclei ⁸Li and ⁹Li at E = 700 and 60 MeV per nucleon were considered. The ⁸Li nucleus was treated on the basis of the three-body α-t-n model, while the ⁹Li nucleus was considered within the α-t-n and ⁷Li-n-n models. The cross sections in question were calculated within Glauber diffraction theory. A comparison of the results with available experimental data made it possible to draw conclusions on the quality of the wave functions and potential used in the calculations.     

140A MeV~(40,48)Ca和~(58,64)Ni炮弹碎裂反应产物的统计擦碎模型计算

用统计擦碎模型计算了140AMeV40,48Ca+9Be和58,64Ni+9Be弹核碎裂反应产物的截面.通过对碎片截面计算结果和实验测量结果的比较发现,采用自由空间的核子-核子反应截面计算时,对非中心反应产物的截面拟合很好,而对中心反应产物的截面有较大高估,而采用饱和密度相关的核子-核子反应截面计算时,对非周边反应产物的截面拟合较好,而对周边反应产物的截面有一定程度的低估.在统计擦碎模型中,对核子-核子反应截面进行细致的介质密度关联,可能会改进计算值与实验值的符合程度.     

New Data on Photoneutron Reaction Cross Sections for 76,78,80,82Se Nuclei

The problem of reliability of the cross section data obtained for partial photoneutron reactions on ^76,78,80,82Se nuclei in beams of quasimonoenergetic annihilation photons by means of neutron multiplicity sorting is discussed by employing objective physical criteria. It is shown that, because of substantial systematic uncertainties, experimental data on the (γ, 1n) and (γ, 2n) cross sections are unreliable. New data satisfying the reliability criteria are obtained for the partial photoneutron reaction cross sections for ^76,78,82Se nuclei by an experimental—theoretical method for evaluating such cross sections and are compared with experimental data and with data evaluated earlier for the isotope ⁸⁰Se. The evaluated integrated cross sections for the total photoneutron reactions on ^76,78,80,82Se nuclei are compared with the predictions of the Thomas-Reiche-Kuhn classical dipole sum rule.

     

Cross sections and isomeric ratios in the photoproduction of 44Sc from heavier nuclei

The yields and isomeric yield ratios in the photoproduction of⁴⁴Sc from ⁴⁵Sc, ⁵⁵Mn, Fe, ⁵⁹Co and ⁷⁵As have been measured by activation methods in the energy region 100–800 MeV. Mean cross sections and isomeric cross-section ratios in the energy region 250–800 MeV have been deduced and the number of valence neutrons available for the (γ, n) reaction estimated. The experimental cross sections are compared both to cascade-evaporation calculations based upon the free-nucleon photopion cross sections and to cross sections calculated with a semi-empirical formula. The isomeric cross-section ratios are compared to calculations based on the statistical formalism by Huizenga and Vandenbosch together with cascade-evaporation theory.     

Ground state reorientation effects in elastic scattering cross sections

Elastic scattering cross sections are shown to be quite sensitive to ground state reorientation amplitudes and cross sections. These effects are dramatically evident when comparing scattering from even-even nuclei with that from high-spin odd-A nuclei, and may affect choices of potentials for odd versus even nuclei. Neutron scattering data from ²³⁵U and ²³⁸U are analyzed via coupled channels methods. The diffraction minima in elastic scattering from ²³⁵U are found to be dominated by reorientation cross sections. The majority of this reorientation is shown to follow from second order virtual nuclear excitations rather than proceeding through amplitudes for direct ground state reorientation.     

Shielded fixed-pole Pomeranchon model for high energy total and differential cross sections

A Regge model with a fixed-pole Pomeranchon and its associated shielding cut is used for π^±p, K^±p and pp scattering at small t and from 6 GeV to NAL and ISR energies. No additional parameters are associated with the cut. The model produces rising total cross sections and anti-shrinkage or non-shrinking diffraction peaks for some s and t. Good fits to total cross sections and to Serpukhov and ISR pp slope parameter data are obtained, and predictions about cross sections and shrinkage at NAL energies are made.     

高电荷态N4+与Na原子碰撞过程中靶原子激发截面的测量

测量了高电荷态Ｎ⁴⁺与Ｎａ原子碰撞中靶原子的发射截面和激发截面，发现ＮａＩ（３ｐ→３ｓ）谱线的激发截面很大，约为１０^-15ｃｍ²．实验给出了发射截面和激发截面数据，并进行了定性的讨论 关键词：     

A study of the photoneutron reactions in 10B and 11B

Absolute (γ, xn) cross sections for ¹⁰B and ¹¹B were measured up to 35 MeV using a quasi-monoenergetic photon beam from positron annihilation in flight. The experimental cross sections were compared with many-particle shell-model calculations and data from previous bremsstrahlung experiments. The ¹¹B photoneutron cross section is discussed with respect to possible isospin splitting. A systematic review of the photoneutron cross sections of the p-shell nuclei integrated up to about 30 MeV seems to show a strong influence of the α-cluster structure of the target nuclei.     

Isotopic and neutron-excess effects in nucleus-nucleus interaction and fusion cross sections

The interaction potentials and fusion cross sections for various nickel and tin isotopes are calculated. The fusion cross sections are computed with allowance for coupling to the channels of low-lying 2⁺ and 3^? vibrational states in the interacting nuclei. Good agreement with the experimental data is obtained. The isotopic dependences of interaction potentials and fusion cross sections of nuclei are analyzed in detail.     

Comparison of the π+ and π− elastic scattering from 12C over the πN (3,3) resonance region

Pion-carbon scattering was measured for both π⁺ and π^? at 162 and 226 MeV. The significant differences observed between the π⁺ and π^? elastic cross sections in the diffraction minima are shown to be of opposite sign below and above the πN (3,3) resonance. In addition, differences between the π⁺ and π^? cross sections are also observed at 162 MeV at backward angles.     

Reaction cross sections for collisions involving exotic light nuclei within the glauber approach

The reaction cross sections for the interaction of exotic nuclei ⁶He and ¹¹Li with ¹²C nuclei are calculated for energies of about 0.8 GeV per nucleon. The cross sections calculated by the exact Glauber formula are compared with their counterparts found by using the formulas of the optical limit, the rigidtarget approximation, and the few-body approximation. The effect of the structure of the nuclei being considered on the calculated cross sections is examined. The root-mean-square radii of the ⁶He and ¹¹Li nuclei are estimated on the basis of experimental data on the cross sections for the interaction of these exotic nuclei with ¹²C nuclei.