平行板静电场法离子引出的对称收集

Dual extraction and collection of ions by parallel electrode method

离子引出的研究在AVLIS工程中有重要的意义,离子引出量和引出时间直接关系到整个系统的离子收集效率.在静电场中,由于等离子体屏蔽效应的存在,等离子体电位要高于正、负极板的电位,而且在靠近正、负极板的两侧均存在鞘层.理论模拟表明在正极板一边也可以引出离子.选取铯(Cs)作为实验对象,研究静电场对Cs等离子体的离子引出,使用安装在两个极板上的法拉第筒收集离子引出信号.实验结果表明,正极板确实可以引出离子,随着外加电压的升高,从正极板一边引出离子的比率降低.

Ion extraction from laser-induced plasma is one of the key problems in atomic vapor laser isotope separation （AVLIS） engineering. In an electrostatic field, the plasma potential is higher than both electrodes due to the plasma shield effect. And sheaths exist on both sides of the electrodes. Using numerical simulation, it has been proven that ions can be extracted by the positive electrode. In conventional ion extraction experiments using an electrostatic field, the ions are only collected at the negative electrode. We focused on the positive electrode as well as the negative collector in our experiments. The Faraday cups, fixed on both electrodes, were used to collect the extracted ions and avoid the effect of power supply. As a result, the positive electrode can also extract ions. The collection ratio of positive and negative collectors decreases, as the applied voltage increases.