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

磁性材料表面多电子沉积工艺研究

基本信息

批准号：
02452034
负责人：
YAMAZAKI Yasunori
金额：
$ 4.22万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

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.)

为了执行该项目，必须获得能够提供低速高电荷离子和高光束质量的离子源。由于研究涉及磁性材料、绝缘体等的离子-固体相互作用只需要弱束流，我们构建了一种紧凑的EBIS（电子束离子源）型离子源。以1.8keV的电子束能量和1x10^<-9>Torr的Ar气压操作离子源，我们成功地获得了300eV/q的Ar^<15+>束流。带有一对永磁体的维恩滤波器也被构建为电荷分离器。多电子捕获过程非常有趣，因为它在捕获事件之前和之后受到电子-电子相关性的强烈影响。作为第一步，我们研究了绝缘体（ZnO+TiO）的库仑爆炸。库仑爆炸发生在目标原子之间，因为 Ar^<q+> (q=1.3,6,9) 捕获的多个电子会引起局部充电。采用TOF技术来识别二次离子的电荷状态。实验结果表明，多个电子捕获发生在相当局部的区域。在之前的工作中，我们研究了正电子-C_<60>相互作用。作为高 q 的扩展，我们已经开始研究慢速高电荷离子与 C_<60> 之间的相互作用，这将为我们提供有关电子捕获事件的时间和空间定位程度和/或电子的信息。 -多电子捕获过程中C_<60>内的电子关联。如果应用粗略的类比，我们可以说主要兴趣是看看 C_<60> 在爆炸过程中是否表现得像气球或肥皂泡。（想象一下，一个气球和一个漂浮在空中的肥皂泡现在开始爆炸。对于气球来说，爆炸立即蔓延到气球表面，然而，对于肥皂泡来说，爆炸发生在局部并且逐步在表面上蔓延。）