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1.
The transmissions of oxygen ions through Al2O3 nanocapillaries each 50 nm in diameter and 10 μm in length at a series of different tilt angles are measured,where the ions with energies ranging from 10 to 60 keV and charge states from 1 up to 6 are involved.The angular distribution and the transmission yields of transported ions are investigated.Our results indicate both the existence of a guiding effect when ions pass through the capillary and a significant dependence of the ion transmission on the energy and the charge state of the ions.The guiding effects are observed to be enhanced at lower projectile energies and higher charge states.Meanwhile,the results also exhibit that the transmission yields increase as the tilt angle decreases at a given energy and charge state.  相似文献   
2.
介绍了使用位置灵敏技术和飞行时间方法研究中低能低电荷态离子-原子碰撞过程中转移电离与单电子俘获过程.对于确定的入射离子电荷态,通过理论分析及与实验数据对比给出了转移电离与单电子俘获截面比RTS随着入射离子速度VP的变化规律和转移电离过程中电离的电子主要来自靶原子的最外亚壳层. 关键词: 转移电离 逃离半径 电离半径 俘获半径  相似文献   
3.
In this paper a projectile ions recoil ions coincidence technique is employed to investigate the target ionization and projectile charge state changing processes in the collision of 0.22-6.35 MeV Cq^+ (q = 1 - 4) ions with argon atoms. The partial cross section ratios of the double, triple, quadruplicate ionization to the single ionization (or the single capture) of argon associated with single electron loss (or single electron capture) by the projectile are measured and compared with the previous experimental results. In the present experiment, it is observed that the ratios of ionization cross sections R associated with single loss and single capture depend strongly on the projectile charge state and vary significantly with different reaction channels as impact energy increases. In addition, this paper gets empirical scaling laws for the ionization cross section ratios R corresponding to the projectile single loss and finds that the ratios of the double ionization to the single ionization associated with single electron capture remain constant in the present energy range.  相似文献   
4.
实验测量了2.2v0—4.2v0(v0为玻尔速度,v0=2.19×108cm/s)的C3+与Ne原子碰撞过程中单电子转移绝对截面.将实验结果与多体经典轨道蒙特卡罗模拟计算结果进行了比较.用电离能的变化、屏蔽效应、动态关联对实验和理论计算结果间的数值差异做了分析.总体上,实验结果与多体经典轨道蒙特卡罗方法计算结果在趋势上相 关键词: 离子-原子碰撞 单电子转移 绝对截面  相似文献   
5.
<正>This paper reports that the transmission of O6+ ions with energy of 150keV through capillaries in an uncoated Al2O3 membrane was measured,and agreements with previously reported results in general angular distribution of the transmitted ions and the transmission fractions as a function of the tilt angle well fitted to Gaussian-like functions were observed.Due to using an uncoated capillary membrane,ourψc is larger than that using a gold-coated one with a smaller value of(?),which suggests a larger equilibrium charge Qin our experiment.The observed special width variation with time and a larger width than that using a smaller(?) were qualitatively explained by using mean-field classical transport theory based on a classical-trajectory Monte Carlo simulation.  相似文献   
6.
在不同入射角度条件下,研究了60keV的O+离子入射孔径分别为50nm和30nm,厚度为10μmAl2O3微孔膜的角分布.实验结果表明离子透射微孔膜时发生了导向效应,随着入射角度的增大,透射于孔径大的微孔膜离子计数下降比较快,透射于孔径小的微孔膜离子计数下降比较缓慢.建立了一个初步的理论模型,对以上现象给出了较好的解释.  相似文献   
7.
实验测量了1.7v0-4.2v0(v0为玻尔速度,v0=2.19×108 cm/s)的C3+与He,Ne,Ar原子碰撞过程中单电子转移绝对截面.将实验结果与多体经典轨道蒙特卡罗模拟计算结果做了比较,发现测量结果与多体经典轨道蒙特卡罗模拟计算结果在趋势上相符.当入射离子速度在1.7v0-2.0v0时,因多体经典轨道蒙特卡罗方法计算时不能考虑多电子关联态俘获和极化效应的影响,实验值大于计算值.当入射离子速度在2.2v0-4.2v0时,由于被俘获电子对入射离子的不完全屏蔽,加上电子间的动态关联及有效电荷的影响,实验结果先与多体经典轨道蒙特卡罗计算结果符合很好,而后逐渐大于计算值.此外,还根据转移电离与单电子俘获的截面比简单分析了转移电离机制.  相似文献   
8.
利用兰州大学2×1.7MV串列加速器离子-原子碰撞实验终端上产生的单核子能量为20-500 keV的Cq+和Oq+(q=1-4)离子与He原子碰撞.采用符合测量方法和多参数数据获取系统得到了散射离子与反冲离子电荷态的二维谱,从而分别得到直接电离、入射离子俘获电子和入射离子损失电子截面与总截面的截面比Rdirect,Rcapture和Rloss,并对强扰动能区的各个反应道之间竞争关系及同一反应道在不同碰撞体系中所表现出的实验规律进行了比较和定性分析.  相似文献   
9.
The ratios of transfer ionization (TI) to single-electron capture (SC) cross sections have been measured for the collisions of partially stripped C^q+ ions (q = 1-4) with He. The collision velocity ranges from 0.7 to 4.4 vo (vo is the Bohr velocity). The projectile-ion and recoil-ion coincidence technique is used to separate the processes of TI and SC. The ratios reach the maximum when the velocity is about 3.7 vo. This can be explained qualitatively based on the two-step mechanism. The experimental results are also compared with the results calculated using the classical trajectory Monte Carlo (CTMC) method. The CTMC results are in agreement with the experimental data basically. The discrepancies in higher velocity region are interpreted by the effective charge effect.  相似文献   
10.
This paper reports that the ratios of double to single electron loss cross-section (R) of O^2+ in collision with Ar and He at the velocity of 1 -4 vo(vo is the Bohr velocity) have been obtained by the coincidence technique. The trend of R - V in the experiment indicates that the effective charge varies with injected velocity. The effective charge can be obtained by the n-body classical trajectory Monte Carlo method, which is interpreted by the molecular Coulomb over barrier model.  相似文献   
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