碱金属锑化物光电阴极的高场亮度极限
High-Field Brightness Limits of Alkali-Antimonide Photocathodes
- Tsinghua University（清华大学）
- Sichuan University（四川大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究在超过100 MV/m的射频枪中验证了碱金属锑化物光电阴极的稳健光发射，首次系统测量其高场亮度极限，发现近阈值发射可降低固有发射度并提升亮度。
AI中文摘要：
将电子源的亮度极限推向更高水平，需要同时最小化固有发射度并最大化加速电场。碱金属锑化物光电阴极在低电场下表现出优异的性能，然而由于其强烈的真空敏感性，其高场光发射物理机制仍知之甚少。在此，我们展示了碱金属锑化物光电阴极在峰值电场超过100 MV/m的射频电子枪中具有稳健的光发射性能，量子效率在两周以上保持在1%以上，从而实现了对其高场亮度极限的首次系统性测量。所测得的固有发射度对电场的依赖性直接揭示了高场下的光发射物理机制。近阈值光发射进一步降低了固有发射度，提高了可达到的亮度，并揭示了表面粗糙度带来的限制。这项工作为先进光电阴极开辟了高场领域，拓展了电子源的亮度极限。
英文摘要：
Pushing the brightness limit of electron sources requires simultaneously minimizing the intrinsic emittance and maximizing the accelerating field. Alkali-antimonide photocathodes exhibit excellent properties at low fields, yet their high-field photoemission physics remains poorly understood owing to acute vacuum sensitivity. Here, we demonstrate robust photoemission from alkali-antimonide photocathodes in a radio-frequency gun at peak fields exceeding 100 MV/m, with quantum efficiency maintained above 1% for more than two weeks, enabling the first systematic measurements of their high-field brightness limits. The measured field dependence of the intrinsic emittance provides direct insight into photoemission physics at high fields. Near-threshold photoemission further reduces the intrinsic emittance, increasing the attainable brightness, and reveals constraints imposed by surface roughness. This work opens the high-field regime for advanced photocathodes, extending the brightness limits of electron sources.
