180keV O6+离子与锥形玻璃毛细管相互作用研究

实验研究了强流（几个nA/mm2）180 keV O6+离子穿越微米尺度锥形玻璃毛细管的聚焦效应.结果表明,毛细管出口处束流密度比入口处束流密度增加了6~7倍,且出射离子保持原有的电荷态及能量.此外我们发现,当毛细管倾斜一定角度时,离子出射方向偏向毛细管管轴方向.基于自组织充电模型对上述实验结果进行了讨论.     

刻槽绝缘平行板对电子束的导向效应研究

采用不同材质的刻槽绝缘平行板,包括高纯度石英玻璃、聚四氟乙烯（Teflon）、酚醛树脂（电木）和聚甲醛板（赛钢板）,并在15 pA/mm2 ~14.3 nA/mm2范围内改变入射流强,利用1 500 eV电子束入射上述绝缘平行板,实验研究了上述平行板对电子束的导向行为。实验发现,上述电子束通过上述平行板时存在明显的导向现象,其导向行为与束流流强和绝缘材质无关。据此,可排除绝缘平行板内表面沉积电荷自组织充放电过程中,以绝缘材料的面电阻和体电阻对地泄放的线性形式放电过程。Adopting several grooved parallel plates made by different insulators, such as high-purity fused quartz, Teflon, Bakelite and POM (Polyformaldehyde), and further adjusting the electron beam current in a wide range (tens of pA~tens of nA), the discharging mechanism in the self-organizing charge and discharge processes of electron guiding was investigated and discussed by using 1 500 eV incident electron beam. The present results show that, the electron guiding behaviors are obviously existing when such electron beam is transmitted through the above grooved insulating parallel plates, which are independent on beam current and insulators. Our results suggest that, the possibilities of the accumulated charges on inner-surface of grooved parallel plates linearly discharging through surface and bulk resistances of plates into the ground should be excluded.     

利用HIRFL-CSR开展分子离子复合离解研究的可行性分析

介绍了储存环高精度分子谱学研究的科学意义、 国内外研究现状和利用HIRFL-CSR开展该项研究的优势, 着重论证了HIRFL-CSR分子离子注入实验环的总体设计方案和技术方案。 通过在HIRFL-CSR实验环上增建一条分子离子注入线, 将实验环改造成能兼顾现有物理实验和大分子物理研究的综合性研究平台, 为分子离子复合离解研究提供良好的技术支撑。 特别是质量数大于70的分子离子, 能显著提高其能量分辨。 In the present paper, it is introduced the scientific background and the current status of the high precision spectroscopy of the molecular ions at cooler storage ring. The advantages to study the dissociative recombination(DR) processes using cooler storage ring CSRe are discussed. The physics design,the main parameters of the injection beam line and the injection of the molecular ions into the CSRe and the key techniques are described in detail. With a new injection beam line,HIRFL-CSRe will be reconstructed to a multi discipline research platform,offering good opportunities for the study of DR processes of molecular ions,especially for that of the molecular ions of m>70 amu with much improved resolution.     

Multi-Electron Processes in 4.15-11.08 keV/u^13C^6＋ on Argon Collisions

The relative partial cross sections for ^13C^6＋ -Ar collisions at 4.15-11.08 ke V/u incident energy are measured. The cross-section ratios σ^2E/σ^SC, σ^3E/σ^SC, σ^4E/σ^SC and σ^SE/σ^SC are approximately the constants of 0.514-0.05, 0.204-0.03, 0.064-0.03 and 0.024-0.01 in this region. The significance of the multi-electron process in highly charged ions （HCIs） with argon collisions is demonstrated （σ^ME/σ^SC as high as 0.794-0.06）. In multi-electron processes, it is shown that transfer ionization is dominant while pure electron capture is weak and negligible. For all reaction channels, the cross-sections are independent of the incident energy in the present energy region, which is in agreement with the static characteristic of classic models, i.e. the molecular Coulomb over-the-barrier model （MCBM）, the extended classical over-the-barrier model （ECBM） and the semiempirical scaling laws （SL）. The result is compared with these classical models and with our previous work of ^13C^6＋ -Ne collisions [Chin. Phys. Lett. 23 （2006） 95].     

180 keV O6+离子与锥形玻璃毛细管相互作用研究

实验研究了强流（几个nA/mm²）180 keV O⁶⁺离子穿越微米尺度锥形玻璃毛细管的聚焦效应.结果表明,毛细管出口处束流密度比入口处束流密度增加了6～7倍,且出射离子保持原有的电荷态及能量.此外我们发现,当毛细管倾斜一定角度时,离子出射方向偏向毛细管管轴方向.基于自组织充电模型对上述实验结果进行了讨论.     

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.     

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     

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.     

Effects of electron correlation and the Breit interaction on one- and two-electron one-photon transitions in double K hole states of He-like ions(10 ≤ Z ≤ 47)

The x-ray energies and transition rates associated with single and double electron radiative transitions from the double K hole state 2s2p to the 1s2s and 1s^2 configurations of 11 selected He-like ions(10 ≤ Z ≤ 47) are calculated using the fully relativistic multi-configuration Dirac–Fock method(MCDF). An appropriate electron correlation model is constructed with the aid of the active space method, which allows the electron correlation effects to be studied efficiently. The contributions of the electron correlation and the Breit interaction to the transition properties are analyzed in detail. It is found that the two-electron one-photon(TEOP) transition is correlation sensitive. The Breit interaction and electron correlation both contribute significantly to the radiative transition properties of the double K hole state of the He-like ions. Good agreement between the present calculation and previous work is achieved. The calculated data will be helpful to future investigations on double K hole decay processes of He-like ions.