Characterization of a high-intensity unipolar-mode pulsed ion source with improved magnetically insulated diode
Characterization of a high-intensity unipolar-mode pulsed ion source with improved magnetically insulated diode
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DOI：
10.1063/1.1529303
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发表时间：
2003-01
影响因子：
1.6
通讯作者：
X. P. Zhu;M. Lei;Z. Dong;T. Ma
中科院分区：
文献类型：
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作者：
X. P. Zhu;M. Lei;Z. Dong;T. Ma
为了产生用于材料表面改性的高强度脉冲离子束（HIPIB），研制了一种改进外磁场系统的磁绝缘离子二极管（MID），并将其安装在TEMP-6型强流脉冲离子源上。基于介质高压闪络原理，外磁场MID工作在单极模式，利用马克思发生器供电的双同轴脉冲形成线（PFL）形成纳秒级单极脉冲。一个特殊设计的阴极已被构造与一个叉连接到两个对称安装的变压器，以改善磁场的效果，从而增加离子束的产生和传播的稳定性。结果表明，HIPIB的有效产生主要取决于磁场强度、反向气压、PFL输出开关和外磁场MID的阴阳极（A-K）间隙。在直流充电电压为8 kV时，磁场电源系统的磁场强度是合适的。合适的A-K间隙距离是不均匀的，其值从6到8 mm变化。在马克思发生器的充电电压为40 kV时，反向和输出开关的合适气体压力分别为约1.2和2.4 atm。最有效的等离子体产生和离子提取导致HIPIB的最大输出，峰值离子电流密度为300 A cm-2，束脉冲宽度为80 ns（半峰全宽），加速脉冲为300-350 kV，脉冲宽度为70 ns。
A magnetically insulated ion diode (MID) with an improved external-magnetic field system has been developed and installed onto a TEMP-6-type high-intensity pulsed ion source in order to produce a high-intensity pulsed ion beam (HIPIB) for surface modification of materials. The external-magnetic field MID is operated in unipolar mode based on dielectric high-voltage flashover, and a double coaxial pulse-forming line (PFL) powered with a Marx generator is used to form the unipolar pulse of nanosecond width. A specially designed cathode has been constructed with a forked connection to two symmetrically installed transformers to improve the effect of the magnetic field and thus increase the stability of generation and propagation of the ion beam. It was found that the efficient generation of HIPIB mainly depended on the magnetic field strength, the gas pressures in reverse and output switches of PFL, and the anode–cathode (A–K) gap of the external-magnetic field MID. A proper magnetic field strength was found with magnetic field power system at dc charging voltage of 8 kV. The proper A–K gap distance is not uniform with the value varied from 6 to 8 mm. Suitable gas pressures for reverse and output switches were about 1.2 and 2.4 atm, respectively, at a charging voltage of 40 kV to the Marx generator. The most efficient plasma generation and ion extraction led to a maximum output of HIPIB with a peak ion current density of 300 A cm−2 and a beam pulse width of 80 ns (full width at half maximum), at an accelerating pulse of 300–350 kV with a pulse width of 70 ns.