Quasielastic Scattering of the Halo Nucleus ^6He at 25 MeV／u from a ^9Be Target

The differential cross sections of quasielastic scattering of a 25 MeV/u ^6He from ^9Be target have been measured.The double-folding model approach is applied to generate the real part of the optical potential. The imaginary potential parameters as well as some of the real potential parameters are studied in comparison with the experimental data. The effect of the unstable nucleus is discussed.     

晕核6He（25 MeV/u）的单、双中子转移截面测量

实验测量了25 MeV/u 的6He+9Be反应中的单、双中子转移微分截面. 利用反应耦合道模型初步分析了实验数据, 计算大体重现截面值. 转移反应对末态有相当的选择性, 并且双中子转移截面主要来自到基态的一步过程. 后角度截面的上升可能与连续态的耦合有关. Differential cross sections for quasi elastic scattering at forward angles and for 1n and 2n transfer reaction at backward angles induced by 6He at 25 MeV/u from 9Be target were measured. The experimental data were analyzed in the framework of the CRC model. The raise at backward angle of the 1n and 2n transfer cross section can not reproduced by the current calculation.     

Applicability of ~9Be global optical potential to description of ~(8,10,11)B elastic scattering

We achieved a set of 9Be global phenomenological optical model potentials by fitting a large experimental dataset of the elastic scattering observable for target mass numbers from 24 to 209.The obtained 9Be global optical model potential was applied to predict elastic-scattering angular distributions and total reaction cross-sections of 8,10,11B projectiles.The predictions are made by performing a detailed analysis comparing with the available experimental data.Furthermore,these elastic scattering observables are also predicted for some lighter targets outside of the given mass number range,and reasonable results are obtained.Possible physical explanations for the observed differences are also discussed.     

Elastic Scattering of 6He + p at 82.3MeV/nucleon

Differential cross sections for the elastic scattering of halo nucleus 6He on proton target were measured at 82.3 MeV/u. The experimental results axe well reproduced by optical model calculations using global potential KD02 with a reduction of the depth of real volume part by a factor of 0.7. A systematic analysis shows that this behavior might be related to the weakly bound property of unstable nuclei.     

Experimental study of the elastic scattering of ~(10)Be on ~(208)Pb at the energy of around three times the Coulomb barrier

Elastic scattering of 10Be on a 208Pb target was measured at ELab=127 MeV,which corresponds to three times the Coulomb barrier.The secondary 10Be beam was produced at the Radioactive Ion Beam Line in Lanzhou of the Heavy-Ion Research Facility in Lanzhou.The angular distribution of elastic scattering in the 10 Be+208Pb system shows a typical Fresnel diffraction peak.Optical model analysis of the angular distribution was performed using the Woods-Saxon,double-folding and global potentials.With the global potential,different density distributions were used.The results indicate that different density distributions for the projectile induce distinct effects in the angular distribution.     

Quasi—elastic Scattering of a Secondary ^6He Beam on a ^9Be Target at 25MeV／Nucleon

The quasi-elastic scattering of a secondary ^6He beam (25MeV/n) on a ^9Be target has been measured for the first time with the application of a sophisticated tracking detector system.The angular distribution is reported.A phenomenological optical potential is obtained by fitting the experimental data,which encourages more accurate experimental measurements.     

Microscopic study of 7Li-nucleus potential

A microscopic approach is employed to study the optical potential for the 7Li-nucleus interaction system without any free parameters.It is obtained by folding the microscopic optical potentials of the constituent nucleons of 7Li over their density distributions.We employ an isospin-dependent nucleon microscopic optical potential,which is based on the Skyrme nucleon-nucleon effective interaction and derived using the Green's function method,as the nucleon optical potential.The harmonic oscillator shell model is used to describe the internal wave function of 7Li and obtain the nucleon density distribution.The 7Li microscopic optical potential is used to predict the reaction cross-sections and elastic scattering angular distributions for the target range from 27Al to 208Pb and energy range below 450 MeV.Generally,the results can reproduce the measured data reasonably well.In addition,the microscopic optical potential is comparable to a global phenomenological optical potential by fitting the presently existing measured data.     

Optical Potential Parameters of Weakly Bound Nuclear System 17F+13C

Elastic scattering angular distributions of the 14^N＋16^O system and the angular distributions of transfer reaction 16^O（14^N,13^C）17^F at ELab=76.2 MeV and 57 MeV have been measured and calculated by means of the exact finiterange distorted-wave Born approximation with the PTOLEMY code. The optical potential parameters for the weakly bound nuclear system 17^F＋13^C have been deduced and applied to analyse the elastic scattering angular distributions of the similar systems 17^F＋12^C and 17^F＋14^N which are taken from literature. The result shows that the transfer reaction with stable projectile and target combination can be used as an alternative method to extract the optical potential parameters for the weakly bound nuclear system.     

Global optical model potential describing 12C-nucleus elastic scattering

We construct a new global optical model potential to describe the elastic scattering of ¹²C. The experimental data of elastic-scattering angular distributions and total reaction cross sections for targets from ²⁴Mg to ²⁰⁹Bi are considered below 200 MeV within the framework of the optical model. The results calculated using the derived global optical potential are then compared with the existing experimental data. The reliability of the global optical potential is further tested by predicting the elastic scattering data out of the mass and energy ranges, within which the global potential parameters are determined, and reasonable results are also obtained.     

Optical Potential Parameters for Halo Nucleus System ^6He＋^12C from Transfer Reaction ^11B（^7Li, ^6He）^12C

The optical potential parameters for the halo nucleus system ^6He＋^12C are extracted from fits to the measured angular distributions of ^11B（^7Li, ^6He）12C reaction at energies of 18.3 and 28.3MeV with distorted-wave Born approximation analysis. The characters of the obtained optical potentiM parameters are basically consistent with the results extracted from the fits to the elastic-scattering angular distributions in the literature.     

半微观质子光学势

基于原子核壳模型单体密度矩阵的折叠模型计算光学势的实部,配以唯象光学势虚部,构造半微观光学势.通过拟合质子弹性散射实验数据,得到适用于质量数28~90,能量到200 MeV的半微观质子光学势.该光学势用于质子弹性散射计算分析,在参数大为减少的情况下,计算得到的角分布和分析本领与实验数据的符合程度,总体上好于Koning-Delaroche普适光学势的计算结果.     

Elastic scattering of metastable He(21,3 S) atoms by Na(32 S) atoms at 68 meV

The spectroscopy of metastable states is used to make the first experimental measurement of the total differential elastic-scattering cross sections of metastable helium atoms in 2³ S and 2¹ S states by sodium atoms in the ground state at interaction energy 68 meV in the center-of-mass system. To analyze the experimental data, the partial scattering phases are calculated using the method of phase functions in the optical potential approximation. The analysis makes it possible to give a more detailed interpretation of the structure of the differential cross section. The computed integral cross sections, specifically, Penning ionization, diffusion, viscosity, and spin exchange are discussed.     

透射式内调焦宽光谱光学系统的设计与分析

为了在实现系统内调焦的同时保证宽光谱系统的优良像质,通过合理选材对宽光谱光学系统中存在的位置色差以及二级光谱进行校正,并提出了一种内调焦宽光谱光学系统的设计方法.建立内调焦消色差的数学模型,推导系统设计所需满足的公式.结合提出的数学模型与推导出的公式,以焦距为90mm、F数为2.8、具备内调焦功能的宽光谱光学系统为例进行验证.结果表明,系统可在420~900nm的宽光谱范围内对0.2~200km位置内的目标进行色差校正,验证了内调焦宽光谱光学系统设计方法与消色差数学模型的正确性.     

Folding model analysis of pion elastic and inelastic scattering from 6Li and 12C

π ^±-Nucleus scattering cross sections are calculated applying the Watanabe superposition model with a phenomenological Woods-Saxon potential. The phenomenological potential parameters are searched for π ^± scattering from ⁶Li and ¹²C to reproduce not only differential elastic cross sections but also inelastic and total and reaction cross sections at pion kinetic energies from 50 to 672 MeV. The optical potentials of ⁶Li and ¹²C are calculated in terms of the alpha particle and deuteron optical potentials. Inelastic scattering has been analyzed using the distorted waves from elastic-scattering data. The values of deformation lengths thus obtained compare very well with the ones reported earlier.     

Microscopic <Emphasis Type="Italic">K</Emphasis><Superscript>+</Superscript>-nucleus optical potential and calculations of differential elastic-scattering cross sections and total reaction cross sections

The differential elastic-scattering cross sections and the total reaction cross sections for the interaction of K ⁺ mesons with ¹²C and ⁴⁰Ca nuclei at beam momenta of 0.635, 0.715, and 0.8 GeV/c are calculated. The microscopic optical potential derived in the high-energy approximation is used in these calculations. It is determined by the amplitude for kaon-nucleon scattering and the density distribution of pointlike nucleons of the target nucleus. In the high-energy approximation, the Klein-Gordon-Fock equation reduces to the form of the Schrödinger equation. It is shown that small distinctions between the reduction methods do not lead to significant changes in differential elastic-scattering cross sections, but the effects of relativization as such are quite large. Good agreement with experimental data on elastic K ⁺ A scattering is attained. The total reaction cross sections can be described upon adding, to the volume potential, a term that takes the form of its derivative and which has a maximum at the periphery, its contribution being fitted to experimental data.