Differential partial ionization cross sections for 10–24 keV electrons colliding with helium and neon atoms
Differential partial ionization cross sections for 10–24 keV electrons colliding with helium and neon atoms
复制标题
10-24 keV 电子与氦和氖原子碰撞的微分部分电离截面
DOI：
10.1088/0953-4075/36/8/309
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
R. Shanker
中科院分区：
文献类型：
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作者：
R. Singh;R. Shanker
用电子-离子符合技术测量了氦原子和氖原子在10-24 keV电子碰撞下的相对微分部分电离截面。测量是通过采用一个飞行时间质谱仪的离子和一个通道电子倍增器的电荷分析工作在脉冲计数模式，用于检测非歧视的能量慢电子喷射在90°入射电子束方向。电荷态为n的离子的电荷态分数Fn被发现是几乎不变的碰撞能量。目前的结果表明，多电荷离子的靶原子是由不同的机制，即通过直接多重电离或通过内壳层电离，然后通过非辐射跃迁，例如，通过俄歇过程结合shake-off跃迁。我们的实验结果与基于内壳层电离截面与电荷态丰度折叠的计算结果之间得到了很好的一致性，这是由于相应的初始内壳层空位的衰变。
The relative differential partial ionization cross sections of helium and neon atoms for 10–24 keV electron impact have been measured by using an ejected electron–ion coincidence technique. Measurements were accomplished by employing a time-of-flight mass spectrometer for charge analysis of the ions and a channel electron multiplier working in a pulse-counting mode for detecting the slow electrons of non-discriminated energies ejected at 90° to the incident electron beam direction. The charge state fractions Fn of ions with charge states n are found to be nearly invariant with the impact energy. The present results show that the multiply charged ions of the target atoms are produced by different mechanisms, namely by a direct multiple ionization or by inner shell ionization followed by non-radiative transitions, for instance, by an Auger process combined with shake-off transitions. A good agreement is obtained between our experimental results and the calculations based on inner shell ionization cross sections folded with charge state abundances, which result from the decay of the corresponding initial inner shell vacancies.