A scheme is presented for pulsing of a cesium sputter negative ion source by periodically switching on and off the high voltage driving the sputtering process. We demonstrate how the pulsed ion beam can be used in combination with a pulsed laser (6 ns pulse length) that has a 10 Hz repetition rate to study the photodetachment process, where a negative ion is neutralized due to the absorption of a photon. In such experiments, where the ion beam is used only for a small fraction of the time, we show that the pulsed mode operation can increase the lifetime of a cathode by two orders of magnitude as compared with DC operation. We also investigate how the peak ion current compares with the ion current obtained when the source is run in a DC mode. We find that the peak current in the pulsed mode is strongly dependent on the ion species. In some cases, we observed a strong enhancement, whereas others showed only a moderate enhancement, or even a decrease, in the peak current. We conclude that the pulsed mode operation can be of great value when the negative ion to be investigated requires cathodes that have short lifetimes, expensive materials, or those with relatively small ion beam yields, in the latter case limited to elements with large enhancement factors.

中文翻译：

---

以脉冲模式操作铯溅射源

提出了一种通过周期性地打开和关闭驱动溅射过程的高压来脉冲铯溅射负离子源的方案。我们演示了如何将脉冲离子束与具有 10 Hz 重复率的脉冲激光（6 ns 脉冲长度）结合使用，以研究光分离过程，其中负离子由于光子的吸收而被中和。在此类实验中，离子束仅用于一小部分时间，我们表明，与直流操作相比，脉冲模式操作可以将阴极的寿命增加两个数量级。我们还研究了峰值离子电流与源在 DC 模式下运行时获得的离子电流的比较。我们发现脉冲模式下的峰值电流强烈依赖于离子种类。在某些情况下，我们观察到了强烈的增强，而其他人仅显示峰值电流中度增强，甚至下降。我们得出的结论是，当要研究的负离子需要寿命短、材料昂贵或离子束产率相对较小的阴极时，脉冲模式操作可能具有重要价值，在后一种情况下，仅限于具有大增强系数的元件。