AZUMA Toshiyuki University of Tokyo, College of Arts and Sciences, Research Associate, 教養学部, 助手 (70212529)
KOMAKI Ken-ichiro University of Tokyo, College of Arts and Sciences, Professor, 教養学部, 教授 (40012447)
|Budget Amount *help
¥6,600,000 (Direct Cost : ¥6,600,000)
Fiscal Year 1991 : ¥1,800,000 (Direct Cost : ¥1,800,000)
Fiscal Year 1990 : ¥4,800,000 (Direct Cost : ¥4,800,000)
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.)