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Electron correlation multi Auger electron emission from hollow atoms

空心原子的电子相关多俄歇电子发射

基本信息

批准号：
11440124
负责人：
KOBAYASHI Nobuo
金额：
$ 9.09万
依托单位：
Tokyo Metropolitan University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

Multi-electronic excited states which are produced by multi-electron capture reaction of highly charged ions in collisions with neutral molecules are known as hollow atoms because their inner shells have vacancies while the outer shells have occupied by a lot of electrons. If kinetic energies and ejected angles of more than two Auger electrons which are ejected from the hollow atom at the same time are measured, we can regard the experimental result as the direct observation the electron correlation effect. In order to obtain a wide solid angle and sufficient energy resolution, we have chosen the combination of a magnetic-trap-type drift tube with weak magnetic field and a two-dimensional position sensitive detector. A detector which can be used in the magnetic field and has high speed response is necessary for this experimental setup. We have contrived a new detector which using a resistive film anode combined with a modified backgammon with weighted capacitors readout pad and have developed it successfully. In time of-flight measurements using a high-speed digital oscilloscope, we have achieved a very good time resolution of less than 1 ns by the developing of a new algorithm for analysis of time spectra. Highly charged ions are provided by an electron cyclotron resonance ion source in Tokyo Metropolitan University. For the time-of-flight measurements, the ion beam is chopped by an electric pulse applied to an electrode. As a target gas, we have prepared a supersonic molecular beam for obtaining good time and spatial resolutions. Finally we have constructed an apparatus for the multi-Auger electron spectroscopy with the combination of some devices described above. In this setup, the charge of ions after both of the electron capture and the electron emission should be analyzed for the coincidence measurements with the ejected electrons which give us the information about the electronic states of the hollow atoms.

高电荷态离子与中性分子碰撞产生的多电子俘获反应产生的多电子激发态被称为空心原子，因为它们的内壳层有空位，而外壳层被大量电子占据。如果测量两个以上俄歇电子同时从空心原子中射出时的动能和射出角，就可以把实验结果看作是对电子关联效应的直接观察。为了获得宽的立体角和足够的能量分辨率，我们选择了磁阱型漂移管与弱磁场和二维位置灵敏探测器的组合。该实验装置需要一种能在磁场中使用的、具有高速响应的探测器。我们设计了一种新的探测器，它采用电阻膜阳极结合改进的双陆棋与加权电容读出垫，并已研制成功。在使用高速数字示波器的飞行时间测量中，我们通过开发用于分析时间谱的新算法，实现了小于1 ns的非常好的时间分辨率。高度带电的离子由东京首都大学的电子回旋共振离子源提供。对于飞行时间测量，离子束被施加到电极的电脉冲截断。为了获得良好的时间和空间分辨率，我们制备了一束超声分子束作为靶气体。最后，我们将上述几种器件组合起来，构造了一套多俄歇电子能谱装置。在这种装置中，离子在电子捕获和电子发射之后的电荷应该被分析用于与射出的电子的符合测量，这给了我们关于中空原子的电子状态的信息。