逐束团位置对束流横向反馈的影响分析

摘要

Background: As the transverse instability of beam has been suppressed effectively in storage ring, further optimization would mainly refer to the residual coupled instability for individual-bunch in transverse feedback (TFB) system upgrade plan in Shanghai Synchrotron Radiation Facility (SSRF). TFB system could affect the transverse motion of bunched beam. Purpose: This study aims to analyze TFB effect on beam to make a definite target of TFB optimization in the future, and to understand the characteristics of coupled-bunch instability. Methods: A bunch-by-bunch position online data acquisition system was employed in the beam experiment, transverse position data with different TFB gain force was obtained for further analysis. By spectrum analysis of bunch-by-bunch position data in MATLAB, transverse oscillation amplitude distribution with TFB gain force and bunch ID were curved. Results: Experimental curves showed that transverse position data with various TFB gain had unregular relationship with the coupled-bunch instability. Conclusion: TFB effect on beam transverse instability evaluated by using bunch-by-bunch position data could offer data support for further research.%为了提升上海光源储存环横向反馈系统的性能,进一步优化抑制束团串内部横向耦合不稳定性,需要更深入了解现有束流反馈系统模式下的工作状态.用逐束团位置在线采集的方法,在束流诊断实验中获取横向反馈系统不同反馈作用力条件下的逐束团位置信息.通过离线频谱分析,得到束团串横向不稳定振荡振幅随反馈作用力及束团分布的变化规律,表明了横向反馈作用力对束流的整体作用具有正相关性,但对不同束团及束团串的作用效果具有较大差异.为更深入的研究束流不稳定性及束流优化提供了数据支持.