多胞超导射频腔整腔调谐场平坦度模拟研究  

Simulation studies on the field flatness tuning of multi-cellsuperconducting radio-frequency cavities

作　　者：王岩 马震宇 徐凯 常强 张志刚 罗琛 黄雪芳 郑湘 赵申杰 赵玉彬 Wang Yan;Ma Zhenyu;Xu Kai;Chang Qiang;Zhang Zhigang;Luo Chen;Huang Xuefang;Zheng Xiang;Zhao Shenjie;Zhao Yubin(Shanghai Advanced Research Institute,Chinese Academy of Sciences,Shanghai 201210,China)

机构地区：[1]中国科学院上海高等研究院,上海201210

出　　处：《强激光与粒子束》2023年第7期96-104,共9页High Power Laser and Particle Beams

基　　金：上海市市级科技重大专项课题(2017SHZDZX02);中国科学院横向科研项目(1102000554)。

摘　　要：简述了用于分析多胞超导射频腔场平坦度调节的微扰理论,推导了场平坦度的理论计算方法。针对超导腔微小范围内的纵向拉伸/挤压,进行理论计算分析与结构-电磁多物理场模拟计算以求得变形前后腔体场平坦度及其变化趋势,所得结果表明:理论分析结果与仿真计算结果基本一致,进一步深入验证了该微扰理论的有效性。在多胞超导射频腔的加工制造、运行过程中的关键环节,国际上广泛采用的两种方法—包括预调谐过程中的“先单胞后整腔”和运行时腔体调谐过程中“整腔拉伸/挤压”方法,基于分析结果,这两种方法正确性和合理性均在理论上得以验证。在超导射频腔腔型设计的第一阶段—单胞优化设计过程中加入结构-电磁多物理场分析,可使腔型优化设计过程更加高效,结果表明:优化后的单胞(包括端胞和中间胞)的频率敏感度应尽可能接近或相等,以保证在腔变形期间始终保持较好的场平坦度。Perturbation theory of multi-cell superconducting radio-frequency(SRF)cavities,which is widelyused in analysis of field flatness adjustment,is briefly described,and theoretical calculation method of field flatness isdeduced.Multi-field coupled simulation calculations are performed for resonant cavities with minor longitudinaldeformation,the field flatness and its trend with deformation quantity are obtained.For two widely adopted methodsfor SRF cavity development,including‘first-single-then-the-whole pre-tuning’and‘whole-cavity stretching/squeezing’during tuning process,theoretical analysis is carried out based on the capacitively coupled LC oscillatormodel of perturbation theory for multi-cell cavities,and meanwhile further verifying multi-field coupled simulationcalculations are performed by combination of CST MWS and ANSYS for three typical SRF 9-cell cavities-for mainLinac of XFEL,TRIUMF e-Linac,and for injector of SHINE as a candidate.It is shown that theoretical analysisresults and simulation results are perfectly consistent with each other.The validity and feasibility of the two widelyadopted methods above are verified and proved to be correct in the scope of perturbation.Cavity shape structure withexcellent acceleration performance and field flatness can be obtained just by adding multi-physics field analysis to theoptimization design of single-cell,which makes the design process of cavity shape more efficient.It is illustrated thatthe tuning sensitivity factors of optimized single-cells including end-cells and mid-cell should be as close or equal aspossible to maintain field-flatness during cavity deformation.

关 键 词：超导射频 微扰理论 场平坦度调节 多场耦合仿真 腔型设计 

分 类 号：TN815[电子电信—信息与通信工程]