The HITRAP project at GSI: trapping and cooling of highly-charged ions in a Penning trap

A decelerator will be installed at GSI in order to provide and study heavy nuclei without or with only few electrons at very low energies or even at rest. Highly-charged ions will be produced by stripping at relativistic energies. After electron cooling and deceleration in the Experimental Storage Ring (ESR) the ions are ejected out of the storage ring at 4 MeV/u and further decelerated in a combination of linear accelerator structures operated in reverse. Finally, they are injected into a Penning trap where the ions are cooled to 4 K by electron cooling in combination with resistive cooling. From here, the ions can be transferred in a quasi DC or in a pulsed mode to different experimental setups. This article describes the technical concepts of this project focused on the Penning trap.      

高能核碰撞中带电多重数快度与能量和中心度的关系

用强子–弦级联模型JPCIAE及相应的Monte Carlo事例产生器研究相对论性核–核碰撞中带电粒子多重数的赝快度密度对能量和中心度的依赖关系.无需另调任何模型参数的条件下,此模型可以同时较好地描述相对论性pp实验数据及PHOBOS和PHENIX实验组的Au+Au实验数据.本文指出:因〈N_part〉并非严格定义的物理量,致使实验上和理论上确定〈N_part〉有一定任意性,从而使得每参加者核子对的带电粒子赝快度密度随着〈N_part〉的增加可能逐渐增大,也可能逐渐减小,因此用它来区分粒子产生机制是欠妥的.     

AuQ+碰撞氦原子单电离的全微分截面

利用三体扭曲波计算了3.6 MeV/amu的Au^Q+ (Q=24,53)碰撞氦原子单电离的全微分截面,其结果与实验数据和其它理论进行了比较,表明全微分截面受到高电荷入射粒子的强烈影响,敲出的电子被“拖拽”沿着向前的方向. 但是,所有的理论结果都不能呈现实验上全微分截面的独特的向前峰.     

数值积分求解均匀带电圆环平面上的电场分布

本文用数值积分的方法计算椭圆积分，求出在均匀带电圆环平面上的场强与电势．     

XYZ particles at Belle

In this paper, I review recent progress in the study of the XYZ particles at Belle. I only focus on studies with charmonium and one or more light mesons in the final states. This covers the X（3872）, X（3915）, Y（4140）, X（4350）, and the charged Z states.     

低速高电荷态离子40Ar16+与云母表面作用中的电子发射研究

报道了由兰州ECR源提供的低速高电荷离子40Ar16 入射到云母表面产生的电子发射的实验测量结果.结果发现,电子发射产额Y与离子入射角ψ有近似1/tanψ的关系.基于经典过垒模型,我们对这一关系进行了理论分析.实验结果和理论结果相当符合,这就间接说明势能电子发射是低速高电荷态离子作用于表面发射电子的一个主要途径.     

Activity Coefficients of Electrolytes from Liquid Membrane Cells. XII. Magnesium,Lanthanum, and Tris(ethylenediamine)cobalt(III) Salts of the 1,5-Naphthalenedisulfonate Anion at 298.15 K

Activity coefficients of the highly charged electrolytes Mgds, La₂ds₃, and [Co(en)₃]₂ds₃ (en = ethylenediamine, ds²⁻=1,5-naphthalenedisulfonate anion), were determined at 298.15 K using liquid-membrane cells. These salts are found not to display large negative deviations from the Debye-Hückel limiting slope in the dilute regions, which characterize the corresponding sulfate salts. Theoretical calculations based on the primitive model (charged hard spheres in an unstructured dielectric medium) reproduce the behavior of these salts correctly up to concentrations of 0.01 mol⋅kg⁻¹ or more (0.1 mol⋅kg⁻¹ for Mgds), although ds²⁻, far from resembling a charged sphere, is a planar ion with charges distant from one another. The Pitzer model parameter values are reported for the activity and osmotic coefficients.     

Atomic structure and collision dynamics with highly charged ions

The research progresses on the investigations of atomic structure and collision dynamics with highly charged ions based on the heavy ion storage rings and electron ion beam traps in recent 20 years are reviewed. The structure part covers test of quantum electrodynamics and electron correlation in strong Coulomb field studied through dielectronic recombination spectroscopy and VUV/x-ray spectroscopy. The collision dynamics part includes charge exchange dynamics in ion-atom collisions mainly in Bohr velocity region, ion-induced fragmentation mechanisms of molecules, hydrogen-bound and van de Waals bound clusters, interference, and phase information observed in ion-atom/molecule collisions. With this achievements, two aspects of theoretical studies related to low energy and relativistic energy collisions are presented. The applications of data relevant to key atomic processes like dielectronic recombination and charge exchanges involving highly charged ions are discussed. At the end of this review, some future prospects of research related to highly charged ions are proposed.     

129Xe30+轰击Ni表面激发靶原子偶极跃迁和禁戒 (M1和E2)跃迁的特征光谱线

报道了用高电荷态离子129Xe30+(150keV) 轰击金属Ni表面，激发的200—1000nm NiⅠ和NiⅡ的特征光谱线的实验结果.实验结果表明：用电荷态足够高的离子作光谱 激发源，无需很强的束流强度（nA量级），便可有效地产生原子和离子的复杂组态间跃迁所 形成的可见光波段的特征谱线，特别是NiⅠ和NiⅡ偶极禁戒的电四极跃迁E2和磁偶极跃迁M1 的特征光谱线.通过分析发现，在禁戒跃迁的谱线中，有些是电子组态相同而原子态不同的 偶极禁戒跃迁光谱线而且NiⅡ的684.84nm谱线较强. 关键词： 光谱 禁戒跃迁 电子组态 高电荷态离子     

高电荷态离子$lt;sup$gt;126$lt;/sup$gt;Xe$lt;sup$gt;$lt;i$gt;q$lt;/i$gt;+$lt;/sup$gt;引起GaN表面形貌变化研究

用不同电荷态的¹²⁶Xe^q+离子（9≤q≤30）在室温下轰击GaN晶体表面,经原子力显微镜分析表明,当q>18,辐照区域由隆起转为显著的刻蚀.被轰击后的GaN晶体表面形貌主要取决于入射离子的电荷态.同时,样品表面形貌还与入射离子的剂量和入射角有关;在实验参数范围,与入射离子的初动能没有明显关系（180 keV≤E_k≤600 keV）.当入射离子的电荷态q=18,与样品表面法线成60°角倾斜入射和垂直表面入射时,样品的表面几乎没有变化,只是倾斜入射后有很微小的隆起;当q＜18时,样品表面膨胀隆起,粗糙度增强,倾斜入射时表面隆起比垂直入射时更明显,而且都有清晰的峰状分界区;当q＞18时,样品表面被蚀刻呈凹陷状,有明显的齿状刻痕,且侵蚀深度与离子剂量近似呈线性关系,倾斜入射时的刻蚀深度大于垂直入射时的刻蚀深度. 关键词： 高电荷态离子 GaN晶体 原子力显微镜 表面形貌