扇形多注强流相对论电子束的产生与传输研究

The generation and transmission research of the fan-shaped multi-beam intense relativistic electron beams

多注相对论速调管相对于常规相对论速调管,每注电子束具有更低的导流系数和更低的空间电荷力,却具有更高的束波转换效率.本文基于这方面的需求,通过三维软件模拟与实验研究了扇形多注强流相对论电子束的产生与传输.通过建立电子枪的三维模型,分析了阴极端面静电场的分布及其对电子束产生的影响;通过粒子模拟获得了发射束流,然后通过粒子跟踪仿真,得到了电子束在空心漂移管和多扇形孔漂移管中传输的束斑图,并对其进行了理论分析与解释.模拟和实验结果表明,电子束在空心漂移管传输过程中不仅绕束自身中心旋转,还绕系统的中心旋转,通过旋转多扇形孔漂移管实现对中的方法可提高传输效率.

Compared with the beam of conventional relativistic klystron, each beam of the multi-beam relativistic klystron has a low per- veance and low space charge force, but it has a high conversion efficiency of beam-wave. According to these requirements, in this paper we investigate the generation and transmission of fan-shaped multi-beam intense relativistic electron beams by the experiment and the simulation with using the three-dimensional software, and analyse the electrostatic field distribution of the cathode end and the influence on the generation of the electron beams by establishing a three-dimensional model of electron gun. The emission currents by the particle-in-cell simulation, then the beam spot pictures of electron beam transmission in a hollow drift tube and multiple fan-shaped hole drift tube by the particle tracking solver are obtained. The theoretical analysis and explanation with the aid of the sheet beam theory are presented. The simulation and experimental results show that the beams rotate not only around their own center, but also around the center of the system in the transmission process of the electron beams in the hollow drift tube. Thus we can increase the transmission efficiency by rotating multiple fan-shaped hole drift tube to align the beams.