Study of the surface of magnetic material with multi-electron cature process

为了实现这一计划，必须得到一个能提供高质量低速高电荷态离子束的离子源。由于在研究磁性材料、绝缘体等离子体与固体相互作用时只需要弱束流，我们已经建立了一个紧凑的EBIS（电子束离子源）型离子源。在电子束能量为1.8keV、Ar气压为1 × 10 ~（-1）Torr的条件<-9>下，获得了300 eV/q的Ar ~（15+）离子束。多电子俘获过程是一个非常有趣的过程，因为它强烈地受到俘获事件前后电子-电子关联的影响。作为第一步，我们研究了绝缘体（ZnO+TiO）的库仑爆炸。由于Ar^&lt;q+&gt;（q= 1.3，6，9）对多个电子的俘获引起了局域充电，靶原子间发生了库仑爆炸。用飞行时间技术确定了二次离子的电荷态，实验结果表明，多电子俘获发生在一个相当局域的区域。在以前的工作中，我们研究了正电子-C_<60>2相互作用。作为对高q的扩展，我们开始研究慢高电荷态离子与C_的相互作用<60>，这将为我们提供关于电子俘获事件的时空局域化程度和/或多电子俘获过程中C_内部电子-电子关联的信息<60>。如果用一个粗略的类比，我们可以说主要的兴趣是看C_在<60>爆炸时的行为是像气球还是像肥皂泡。（Imazine，一个气球和一个肥皂泡漂浮在空气中，现在开始爆炸。在气球的情况下，爆炸立即蔓延到气球表面，然而，在肥皂泡的情况下，爆炸发生在局部，并逐步蔓延到表面。

To perform the project, it is essential to get an ion source which provides low-velocity highly-charged ions with high beam quality. As one needs just a weak beam in studying ion-solid interaction involying magnetic material, insulator, etc., we have built a compact EBIS (Electron Beam Ion Source) type ion souce. Operating the ion source with the electron beam energy of 1.8keV and Ar gas pressure of 1x10^<-9> Torr, we have succeeded to get 300eV/q Ar^<15+> beam. A Wien-filter with a pair of permanent magnets has also been built as a charge separaptor.Multiple electron capture process is very interesting because it is strongly affected by electron-electron correlation before and after the capture events. We have, as the first step, studied a Coulomb explosion of insulator (ZnO+TiO). The Coulomb explosion occurs among target atoms because multiple electron capture by Ar^<q+> (q=1.3,6,9) induce a local charge-up. The TOF technique is employed to identify the charge state of the secondary ion.The experimental results infur that multiple electron capture occurs from a rather localized area. In a previous work, we had studied positron-C_<60> interactions. As an extension to high q, we have started to investigate the interaction between slow highly-charged ion and C_<60>, which will provide us with information on the extent of time and space localization of electron capture events, and/or on electron-electron correlation inside C_<60> during multiple electron capture. If a crude analogy is applied, we may say that the major interest is to see whether C_<60> behaves like a balloon or like a soap bubble during explosion. (Imazine that a balloon and a soap bubble floating in the air now start explosion. In the case of a balloon, the explosion spreads over the balloon surface immediately, how-ever, in the case of a soap bubble, the explosion occurs locally and spreads over the surface step by step.)