Femtosecond response time measurements of a Cs2Te photocathode
Femtosecond response time measurements of a Cs2Te photocathode
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DOI：
10.1063/1.4994224
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发表时间：
2017-07-17
影响因子：
4
通讯作者：
Urakawa, J.
中科院分区：
文献类型：
--
作者：
Aryshev, A.;Shevelev, M.;Urakawa, J.
紧凑型高亮度加速器系统的成功设计和建造与超短电子束的产生密切相关。近年来，利用飞秒激光脉冲在射频电子枪中产生短电子束或预聚束，直接照射高量子效率的半导体光阴极的方法已成为一种有吸引力的研究方向。在这种情况下，测量光阴极响应时间至关重要。随着干涉仪型脉冲分裂器与用于RF枪的商业Ti：Sa激光系统的深度集成的方法，产生预聚束电子束并获得连续可变的电子聚束分离已经成为可能。结合一个众所周知的零相位技术，它使我们能够估计最常用的Cs2 Te光阴极的响应时间。结果表明，Cs2 Te的峰-峰均方根时间响应的顺序为370 fs，从而，它是可能的，产生和控制的相对论电子束的THz序列由一个传统的S波段RF枪。这一结果也可应用于其他阴极材料和电子束时间整形的研究，并进一步打开了构建宽范围可调谐的桌面THz自由电子激光器的可能性。出版社：AIP Publishing
Success in design and construction of a compact, high-brightness accelerator system is strongly related to the production of ultra-short electron beams. Recently, the approach to generate short electron bunches or pre-bunched beams in RF guns directly illuminating a high quantum efficiency semiconductor photocathode with femtosecond laser pulses has become attractive. The measurements of the photocathode response time in this case are essential. With an approach of the interferometer-type pulse splitter deep integration into a commercial Ti:Sa laser system used for RF guns, it has become possible to generate pre-bunched electron beams and obtain continuously variable electron bunch separation. In combination with a well-known zero-phasing technique, it allows us to estimate the response time of the most commonly used Cs2Te photocathode. It was demonstrated that the peak-to-peak rms time response of Cs2Te is of the order of 370 fs, and thereby, it is possible to generate and control a THz sequence of relativistic electron bunches by a conventional S-band RF gun. This result can also be applied for investigation of other cathode materials and electron beam temporal shaping and further opens a possibility to construct wide-range tunable, table-top THz free electron laser. Published by AIP Publishing.