300和600keV O~(7+)离子与宏观玻璃管的相互作用

实验研究了300和600 ke V的O7+离子与宏观玻璃管内壁的相互作用,利用位置灵敏法拉第筒测量了传输离子的偏转角和传输效率随倾斜角的变化关系,观察到偏转角不等于倾斜角的不完全导向现象。实验结果证实,高能入射离子在玻璃管内壁产生的沉积电势相对于入射离子动能横向分量较小,难以使传输离子沿着玻璃管的轴向出射,从而发生不完全导向现象;并且,入射离子的能量越高,导向效应越不明显。     

强流电子束入射弯曲宏观石英管的导向效应研究

研究了强流（~129 nA）、 高能（1 500～1 900 eV）电子束在大角度(9°)弯曲宏观石英管中的导向效应。 实验分别测量了入射流强及能量对出射电子角分布值（FWHM）和传输效率的影响。 实验观察到出射电子角分布FWHM随着入射电子流强和入射电子能量增加变化均不明显; 发现电子传输效率随入射流强增加而增加, 但随入射能量增加而减小, 这与高电荷态离子导向中离子传输效率随入射能量增加而增加的现象相反。 分析发现, 与高电荷态离子导向机制不同, 电子束导向并非是由电子在石英管内壁的自组织充电过程引起的, 而是入射电子与管内壁弹性和非弹性散射碰撞共同作用的结果。 By using an incident electron beam with the high current and high energy, the guiding effect of the bended macroscopic quartz tube for the electron beam has been investigated. The angular distributions of outgoing electrons depending on the current and energy of incident electrons were measured. The dependences of electron transmitted fraction on energy and current of incident electrons are also shown. As the incident electron energy increasing, the electron transmitted fraction increases, but it decreases while the incident electron current increasing. The results have been compared with the present data. This work presents, the process of guiding electrons is essentially different from that of guiding highly charged ions, the guiding electron beam was caused by both elastic and inelastic collisions between electrons and inner walls of quartz tube, rather than self organized charging effect on the surface of inner wall of quartz tube.     

经典过垒模型在Xeq++He碰撞中的应用

采用位置灵敏探测和飞行时间技术研究了高电荷态Xe离子(q=15,17,19,21,23)与He原子碰撞中双电子转移截面与单俘获截面比随入射离子电荷态的变化规律.提出一步过程假定,对扩展的经典过垒(ECB)模型进行了修正,利用修正模型计算得到的单、双电子转移绝对截面与Andersson等人和Selberg等人的实验结果符合得很好,所得截面比与本实验得到的双电子转移截面与单电子俘获截面符合得比较好.     

类氢O、N离子入射Al表面俘获电子布居几率的理论与实验研究

利用“二态矢量模型”详细研究了高电荷态O⁷⁺,N⁶⁺离子入射Al表面时中间里德伯态的形成过程,给出了电子被俘获至不同量子数(n A=2-7)的几率,以及电子俘获至里德伯态最可能的离子-表面距离.计算结果表明,较大的主量子数nA对应较小的里德伯态几率,因此O⁷⁺,N⁶⁺离子入射Al表面时辐射的X射线主要来源于较小的n A至基态的退激.为了验证计算结果,测量了O⁷⁺,N⁶⁺离子入射Al表面的X射线发射谱,并运用FAC程序计算了不同高里德伯态退激到基态的跃迁能(np–1s).实验测量到O,N的K-X射线峰,其特征峰的中心值接近主量子数n=2至n=1的跃迁能,说明发射的X射线主要来源于2p–1s的跃迁,与“二态矢量模型”理论计算的几率一致.     

平行玻璃板对105 keV Ar7+离子的导向效应

研究了平行玻璃板对高流强（约80 nA）105 keV Ar7+离子的导向效应, 利用一维位置灵敏探测器测量了不同倾斜角下出射离子的强度及角分布。 实验结果表明, 平行玻璃板对Ar7+离子有导向作用。 与离子在微孔膜中的导向效应不同, 从平行玻璃板出射的Ar离子角分布的FWHM随着倾斜角的改变而改变, 并且出射离子角分布最大值处对应的观察角不等于倾斜角。 The transmission of 105 keV Ar7+ ions with high incident current (about 80 nA) through the gap formed by a paired parallel glass plates was investigated. The intensity and angular distribution of the transmitted ions for various tilt angles were measured using a one dimensional position sensitive detector. The results indicate the existence of a guiding effect when Ar7+ ions pass through the gap, but it is different from that for ions passing through nonacapillaries. We found a measurable dependence of the full width at half maximum (FWHM) of the transmitted ions as a function of the tilt angle. In addition, when the gap was tilted with respect to the direction of the incident beam, the observation angle related to the center of the transmitted ions profile was not equal to the tilt angle.     

Studies of K-shell x-ray energy shifts induced by MeV/u heavy ions

This paper reports that the K x-ray spectra of the thin target 47Ag, 48Cd, 49In and 50Sn were measured by an HPGe semi-conductor detector in collisions with 84.5 MeV 6C4+ ions. Our experiment revealed the Kα x-ray energy shifts were not obvious and the Kβ1 x-ray energy shifts were about 90～110 eV. The simple model of Burch et al has been previously used to calculate the K x-ray energy shifts due to an additional vacancy in 2p orbit. The present work extends the model of Burch to calculate the x-ray energy shifts of multiple ionized atoms induced by heavy ions with kinetic energy of MeV/u. In addition to our experimental results, many other experimental results are compared with the calculated values by using the model.     

HIRFL-CSR实验环中束流损失机制及寿命研究

分析了在储存环中回旋的离子束与残余气体分子、 内靶和冷却电子束相互作用时的损失机制及相应的束流寿命, 针对兰州重离子加速器冷却储存环实验环内靶模式, 计算了50—500 MeV/u 12C6+, 36Ar18+, 132Xe54+和 238U92+等束流在各种损失机制影响下所对应的束流寿命和总的束流寿命。 结果表明: 影响束流寿命的主要因素是与内靶分子（原子）之间的电荷交换及与冷却电子束之间的辐射复合; 对于重离子束 132Xe54+和 238U92+, 与冷却电子束之间的辐射复合是影响其储存寿命的主要因素。The loss mechanism and lifetime of ion beams in collisions with residual gas, internal target and electrons in e cooler in heavy ion cooler storage rings were studied. The partial beam lifetimes resulting from various loss mechanisms and the total beam lifetimes of 50—500 MeV/u12C6+, 36Ar18+, 132Xe54+ and 238U92+ stored in the experimental ring of the Cooler Storage Ring at the Heavy Ion Research Facility in Lanzhou (HIRFL CSR) were calculated. The calculations indicate that the charge exchange process between ion beams and the internal target, as well as the radiative recombination process with the electrons in e cooler restrict the beam lifetime considerably. For heavy ion beams such as 132Xe54+ and 238U92+, the radiative recombination is the dominant loss mechanism     

高电荷态氩离子与Ne原子碰撞过程中的转移电离截面的研究

采用符合关联实验技术进行的Ar^q+ + Ne (q = 8, 9, 11, 12)碰撞体系中多电子转移过程的研究. 在实验上鉴别了反应中各种电子转移过程, 并测量了转移电离截面. 研究了转移电离截面与反冲离子电荷态的关系, 并利用修正后的分子过垒模型计算结果与实验结果进行了对比分析, 计算结果较合理地描述了实验现象.     

低能高电荷态氩离子与氩原子碰撞反应截面研究

使用位置灵敏技术和飞行时间方法研究了低能高电荷态氩离子与氩原子的碰撞反应,给出了实验测量得到的入射离子电荷交换截面和转移电荷截面,研究了反应截面与不同电荷态参教的关系,并与修正后的分子过垒模型计算结果进行了比较。     

基于HIRFL-CSR的高速高电荷态重离子与原子碰撞X射线谱学实验设计与研究

依据非相对论偶极近似、相对论程函近似、ECPSSR理论及平面波玻恩近似方法,计算了30～500 MeV/u的Ar18+、Kr36+和Xe54+离子与Ar、Kr和Xe原子碰撞过程中辐射电子俘获、非辐射电子俘获及内壳电离截面.在此基础上,结合光子探测器的能量分辨以及炮弹离子跃迁谱线的多普勒效应等因素,针对HIRFL-CSR...