,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: Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China“,”Univers
• 出 处: 核技术（英文版）
• 发表日期: 2019年9期
• 关键词: Beam-current measurement Bunch-by-bunch Touschek lifetime Vacuum lifetime SSRF

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 rou-tine 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 patte 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 pre-sented in detail.