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Emission of Highly-Charged Ions from Solid Bombarded by Energetic Heavy Io

高能重 Io 轰击固体中高电荷离子的发射

基本信息

批准号：
02808040
负责人：
IMANISHI Nobutsugu
金额：
$ 1.02万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
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

The aim of the present study is to produce low-energy highly-charged ions with low momentum dispersion. For the purpose, we bombarded solid surface with energetic heavy ions and measured the yields of various secondary ions.In an energy range below several tens keV, particles are sputtered efficiently from solid target but few particles are charged. The sputtering is caused by cascade elastic collisions. In a MeV energy range, however, inelastic collision overcones the elastic collision and atoms in the target are ionized. If the ionized atoms on. an outermost atomic layer are recoiled by other low-energy secondary atoms, they probably carry charges and move slowly. Therefore, we measured systematically the yields of secondary charged particles as a function of incident energy of heavy ions. Used targets were metallic ones such as C. Al, Ti, Ni, Cu, Ho, W and Au, and an insu ator Al_2O_3. Incident partilces were-C, Si and Ge ions. The following conclusions are obtained :1. Singly-charged ions are. produced by the elastic cascade collision. their yield decreases. monotonically with increasing energy.2. The yields of highly-charged secondary ions increase at first and then decrease with energy. The maximun yields are at energies where the elastic and inelastic collisions compete.3. Other than atomic ions, various cluster ions are observed. The yields decrease monotonically and then increase with energy at the energy range where the inelastic collision is predominant.

本研究的目的是产生低动量色散的低能高电荷态离子。为此，我们用高能重离子轰击固体表面，并测量了各种二次离子的产额。在低于几十keV的能量范围内，粒子可以有效地从固体靶上溅射出来，但带电的粒子很少。溅射是由级联弹性碰撞引起的。然而，在MeV能量范围内，非弹性碰撞覆盖了弹性碰撞，靶中的原子被电离。如果电离原子开启。最外层的原子层受到其他低能次级原子的反冲，它们可能携带电荷，移动缓慢。因此，我们系统地测量了二次带电粒子的产额作为重离子入射能量的函数。所用靶材为C、Al、Ti、Ni、Cu、Ho、W、Au等金属靶材和激活剂Al_2O_3。入射粒子为-C、Si和Ge离子。得出以下结论：1.单电荷离子是。由弹性级联碰撞产生。他们的产量下降了。随着能量的增加而单调。高电荷态二次离子的产额随能量的增加先增加后减少。在弹性碰撞和非弹性碰撞相互竞争的能量处，屈服最大。除了原子离子，还观察到了各种团簇离子。在以非弹性碰撞为主的能量范围内，产额先单调下降，然后随着能量的增加而增加。