主持人：秦  庆 研究员 

　　地  点：主楼A511会议室 

　　时  间：12月25日（周五）上午10：00-12：00 

　　讲座题目：SLS-2 Design Status and Preliminary Studies of Collective Instabilities 

　　内容摘要： 

　　An upgrade of Swiss Light Source (SLS-2) would replace the existing storage ring by a new ultra-low emittance ring, which is under development based on the concepts of multi-bend achromats, longitudinal gradient bends and anti-bends. To accommodate strong quadrupole and sextupole magnets required, vacuum chambers with a small inner radius are needed. Therefore, achieving ultra-high vacuum becomes quite challenging, leading us to consider the use of NEG coating for all beam pipes. Unfortunately, both the small size of vacuum chambers and low conductivity of NEG coating increase the susceptibility of beam to the microwave instability. In this paper, resistive-wall impedance of different NEG-coated chambers and the corresponding microwave instability thresholds are presented. The influences of NEG coating and RF parameters on beam stability are also discussed. 

　　报告人简介： 

　　许海生，清华博士毕业，目前在PSI做博后，主要方向是SLS升级相关的加速器物理。 

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