Development of a novel thermionic RF electron gun applied on a compact THz-FEL facility
Development of a novel thermionic RF electron gun applied on a compact THz-FEL facility
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DOI：
10.1016/j.nima.2017.12.070
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发表时间：
2018-04
影响因子：
1.4
通讯作者：
T. Hu;Y. Pei;B. Qin;Kan Liu;G. Feng
中科院分区：
文献类型：
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作者：
T. Hu;Y. Pei;B. Qin;Kan Liu;G. Feng
目前民用和商业应用的需求导致了基于自由电子激光（FEL）的紧凑型太赫兹（THz）辐射源的发展。皮秒电子枪在FEL-THz装置中起着重要的作用，并引起了极大的关注，因为机器性能对初始条件非常敏感。一种新型的带有外阴极和两个独立可调腔的电子枪由于其显著的特性而被认为是传统电子源的一种有前途的替代方案，相应地，自由电子激光注入器可以在紧凑的布局和高亮度之间实现平衡，受益于EC-ITC枪中的速度聚束特性和RF聚焦效应。然而，EC-ITC电子枪在过去几年中并没有作为FEL注入器的一部分进行广泛的研究。在这方面，为了填补这一空白，发展重点的实验装置的自由电子激光注入器的基础上EC-ITC枪详细描述。在组装前，进行动态束流模拟以研究与聚焦线圈相关联的直线加速器的最佳安装位置，并且基于功率耦合设计和分配建立合适的射频（RF）系统。通过使用典型的诊断方法估计主要参数的基本实验，测试台被证明是功能齐全的。结合动态束流计算，建立了EC-ITC电子枪的性能评估模型，并为FEL注入器提供了间接测试结果。
The current requirements from civil and commercial applications lead to the development of compact free-electron laser (FEL)-based terahertz (THz) radiation sources. A picosecond electron gun plays an important role in an FEL-THz facility and attracts significant attention, as machine performance is very sensitive to initial conditions. A novel thermionic gun with an external cathode (EC) and two independently tunable cavities (ITCs) has been found to be a promising alternative to conventional electron sources due to its remarkable characteristics, and correspondingly an FEL injector can achieve a balance between a compact layout and high brightness benefitting from the velocity bunching properties and RF focusing effects in the EC-ITC gun. Nevertheless, the EC-ITC gun has not been extensively examined as part of the FEL injector in the past years. In this regard, to fill this gap, a development focusing on the experimental setup of an FEL injector based on an EC-ITC gun is described in detail. Before assembly, dynamic beam simulations were performed to investigate the optimal mounting position for the Linac associated with the focusing coils, and a suitable radio-frequency (RF) system was established based on a power coupling design and allocation. The testing bench proved to be fully functional through basic experiments using typical diagnostic approaches for estimating primary parameters. Associated with dynamic beam calculations, a performance evaluation for an EC-ITC gun was established while providing indirect testing results for an FEL injector.