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

为了实施这一计划，必须获得一种能提供高束质量的低速高电荷态离子的离子源。由于在研究涉及磁性材料、绝缘体等的离子-固体相互作用时只需要一个弱束，我们建立了一个紧凑型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~(-9)Torr的离子源上，我们成功地获得了300 eV/Q的Ar~(？)多电子俘获过程是一个非常有趣的过程，因为它在俘获事件前后受到电子-电子关联的强烈影响。作为第一步，我们研究了绝缘体(氧化锌-二氧化钛)的库仑爆炸。靶原子间的库仑爆炸是由于Ar^&lt；q&gt；(q=1.3，6，9)的多重电子俘获引起的局部荷电引起的。用飞行时间技术识别二次离子的电荷态。实验结果表明，多个电子捕获发生在一个相当局域区。在以前的工作中，我们已经研究了正电子-C&60&gt；相互作用。作为高Q的延伸，我们已经开始研究慢高电荷态离子与C&lt；60&gt；之间的相互作用，这将为我们提供有关电子俘获事件的时间和空间局域化程度的信息，和/或在多电子俘获过程中C_&lt；60&gt；内部的电子-电子关联的信息。如果用一个粗略的比喻，我们可能会说，主要的兴趣是看看C&lt；60&gt；在爆炸时的行为是像气球还是像肥皂泡。一个气球和一个漂浮在空中的肥皂泡现在开始爆炸。在气球的情况下，爆炸立即扩散到气球表面，然而，在肥皂泡的情况下，爆炸发生在局部，并逐步扩散到表面。)

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.)