The physics design of HEPS Linac bunching system
The physics design of HEPS Linac bunching system
复制标题
HEPS直线加速器聚束系统的物理设计
DOI：
10.1007/s41605-020-00200-1
复制
发表时间：
2020
影响因子：
0.6
通讯作者：
Jingyi Li
中科院分区：
文献类型：
--
作者：
Shipeng Zhang;Shengchang Wang;Cai Meng;Jingyi Li
高能光子源是我国正在建设的第四代同步辐射光源。它由一个储存环，一个全能量助推器，一个500 MeV的直线加速器和三条运输线组成。直线加速器出口处的脉冲电荷需要高达7 nC。根据对加速器不稳定性和主直线加速器束流动力学的研究，一束脉冲中可能需要单束团和三束团。为了获得高的传输效率和控制发射度的增长，多目标遗传算法被引入到优化这些结构的电磁参数。聚束系统的总传输效率为97%，主聚束的传输效率为95%。8.5nC束流电荷的归一化均方根发射度小于60mmmrad.ConclusionsThe设计的聚束系统，脉冲电荷和束流发射度都很好地满足设计要求。
PurposeThe High Energy Photon Source is a fourth-generation synchrotron radiation source being built in China. It is comprised of a storage ring, a full energy booster, a 500-MeV Linac and three transport lines. The pulse charge at the exit of the Linac is required to be up to 7 nC. Both single bunch and three bunches in a beam pulse might be needed according to the studies on instabilities of the booster and the beam dynamic of the main Linac.MethodsA bunching system consisting of both sub-harmonic and fundamental frequency structures is designed to meet the requirements. To obtain high transmission efficiency and control the emittance growth, multi-objective genetic algorithm is introduced to optimize the electromagnetic parameters of these structures.ResultsIn this paper, detailed optimization process and the final results are presented. The total transmission efficiency of the bunching system is 97%, and the transmission efficiency of the main bunch is 95%. The normalized RMS emittance of 8.5 nC included beam charge is smaller than 60 mm mrad.ConclusionsThe design of the bunching system is presented, and both the pulse charge and the beam emittance well meet the design requirement.