主持人：秦  慶 研究員 

　　地  點：主樓A511會議室 

　　時  間：12月25日（周五）上午10：00-12：00 

　　講座題目：SLS-2 Design Status and Preliminary Studies of Collective Instabilities 

　　內(nèi)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. 

　　報告人簡介： 

　　許海生，清華博士畢業(yè)，目前在PSI做博后，主要方向是SLS升級相關(guān)的加速器物理。 

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