Touschek lifetime study based on the precise bunch-by-bunch BCM system at SSRF  

作　　者：Fang-Zhou Chen Zhi-Chu Chen Yi-Mei Zhou Ning Zhang Bo Gao Xing-Yi Xu Yong-Bin Leng 

机构地区：[1]Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China [2]University of Chinese Academy of Sciences, Beijing 100049, China [3]Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201200, China

出　　处：《Nuclear Science and Techniques》2019年第9期126-133,共8页核技术（英文）

基　　金：supported by the National Natural Science Foundation of China(No.11575282);the Ten Thousand Talent Program

摘　　要：Continuous tracking of bunch charges is the key to maintain stable operations in a storage ring in top-up mode. Recently, a precise bunch-by-bunch beam-current measurement (BCM) system has been developed at the Shanghai Synchrotron Radiation Facility. To avoid the influence of longitudinal oscillation on the amplitudes of the sampling points, a method called two-point equilibrium sampling is introduced. The results, obtained during routine operation time, show that the relative resolution of the measurement of the bunch charges is better than 0.02%. With this high resolution, the new BCM system is able to monitor the bunch-by-bunch beam lifetime. By using the filling pattern information, the Touschek lifetime and the vacuum lifetime can also be calculated. In this paper, the principle of the new method and the experiments is presented in detail.Continuous tracking of bunch charges is the key to maintain stable operations in a storage ring in top-up mode. Recently, a precise bunch-by-bunch beam-current measurement(BCM) system has been developed at the Shanghai Synchrotron Radiation Facility. To avoid the influence of longitudinal oscillation on the amplitudes of the sampling points, a method called two-point equilibrium sampling is introduced. The results, obtained during routine operation time, show that the relative resolution of the measurement of the bunch charges is better than 0.02%.With this high resolution, the new BCM system is able to monitor the bunch-by-bunch beam lifetime. By using the filling pattern information, the Touschek lifetime and the vacuum lifetime can also be calculated. In this paper, the principle of the new method and the experiments is presented in detail.

关 键 词：Beam-current measurement Bunch-bybunch Touschek LIFETIME Vacuum LIFETIME SSRF 

分 类 号：TL[核科学技术]