Production of Ce negative ions in a Cs sputter ion source
Production of Ce negative ions in a Cs sputter ion source
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DOI：
10.1063/1.1150356
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发表时间：
2000-02
影响因子：
1.6
通讯作者：
Y. Saitoh;B. Yotsombat;K. Mizuhashi;S. Tajima
中科院分区：
文献类型：
--
作者：
Y. Saitoh;B. Yotsombat;K. Mizuhashi;S. Tajima
我们发展了一种在铯溅射离子源中稳定产生镧系负离子而不损坏电离器的新技术。粘附在铯离子发生器上的镧系元素由于其诸如低蒸气压和低功函数的特性而使离子发生器的离子化效率劣化。我们已经解决了制造具有预钻孔双层结构的溅射阴极的问题。将压入阴极颗粒中的氧化铈粉末用钨覆盖并钻孔。利用这种阴极，我们实现了从钻孔底部溅射的镧系元素的小立体角发射，并且大部分镧系元素可以通过离子发生器的中心孔。结果，对离子发生器的损害减少，并且离子源的稳定操作成功地实现了600 nA的氧化铈束流连续操作24小时。该技术已应用于其他稀土离子的生产。
We have developed a new technique for stable production of lanthanide negative ions in a cesium sputter ion source without damage to the ionizer. Lanthanide elements sticking to a cesium ionizer deteriorate an ionization efficiency of the ionizer because of their characteristics such as low vapor pressures and low work functions. We have resolved the problem to make a sputter cathode that has a predrilled double layer structure. Cerium oxide powder pressed in the cathode pellet was covered by tungsten and drilled. Using this cathode, we achieved smaller solid angle emission of the sputtered lanthanide elements from the bottom of the drilled hole, and most of them could pass through the center hole of the ionizer. As a result, damage to the ionizer decreased, and stable operation of the ion source was successfully achieved with a cerium oxide beam current of 600 nA for 24 h continuous operation. The technique was applied for production of other rare earth ions.