时变工作点分析算法在上海光源的应用研究  

Research on application of time-varying tune calculation algorithms on SSRF

作　　者：杨星 赖龙伟 陈方舟 YANG Xing;LAI Longwei;CHEN Fangzhou(Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China;University of Chinese Academy of Sciences,Beijing 100049,China;Shanghai Advanced Research Institute,Chinese Academy of Sciences,Shanghai 201204,China)

机构地区：[1]中国科学院上海应用物理研究所,上海201800 [2]中国科学院大学,北京100049 [3]中国科学院上海高等研究院,上海201204

出　　处：《核技术》2020年第12期9-15,共7页Nuclear Techniques

基　　金：中国科学院青年创新促进会(No.2019290)资助。

摘　　要：横向工作点是环形粒子加速器非常重要的特征参数之一,一般不随时间变化,可通过对束流逐圈位置数据做简单的谐波分析得到,但在某些特殊的物理过程中工作点会随时间变化,需要研究并优化时变工作点的算法。储存环注入后残余横向振荡阻尼衰减的过程中因Lattice的非线性效应可能会发生工作点漂移,研究时变工作点的分析算法并对上述物理过程进行分析,可以对储存环的非线性效应进行定量评估。本文首先对小波算法和基本频率的数值分析算法(Numerical Analysis of Fundamental Frequencies,NAFF)在时变工作点分析的适用性进行了分析,并比较了两种算法的性能。结果表明:两种算法均可以实现时变工作点的动态分析,但小波方法性能更好。然后采用小波方法对上海光源储存环注入期间工作点的飘移进行了定量分析,评估了上海光源不同运行周期非线性的强度变化。结果显示:其工作点的飘移在不同时期有不同的表现,总体上非线性效应有增强的趋势。[Background]Tune is one of the most important characteristic parameters of storage ring,it seldom changes over time,hence can be obtained by a simple harmonic analysis on the beam position data.In some particular process,tune will change with time.[Purpose]This study aims to explore and optimize the time-varying tune calculation algorithms for the tune drift caused by the nonlinear effect of Lattice during the decay of the residual transverse oscillation damping,after the injection of the storage ring.[Methods]First of all,the applicability of the wavelet algorithm and numerical analysis of fundamental frequencies(NAFF)algorithm for time-varying tune calculation was analyzed,and their performances were on above physical process of nonlinear effect of the storage ring were compared.Then the better Morlet wavelet algorithm was employed to quantitatively analyze the drift of tune during the injection of the Shanghai Synchrotron Radiation Facility(SSRF)storage ring and evaluate the nonlinear intensity changes of the SSRF during different operating period.[Results]Algorithm comparison results show that both algorithms can realize the dynamic analysis of time-varying tune,but the wavelet method shows better performance.Evaluation results of nonlinear strength change of SSRF storage ring show that when the data analysis window is selected as 6000 cycles,a track offset change 0.3 mm,and tune change as small as 0.0001 can be detected.During the period of storage ring injection,the tune changes obviously.[Conclusions]By applying the morlet wavelet algorithm,the complete trajectory of the tune drift can be tracked.

关 键 词：上海光源 非线性 时变工作点 基本频率的数值分析算法 小波分析 

分 类 号：TL99[核科学技术—核技术及应用]