Bunch-by-bunch beam lifetime measurement at SSRF

Lifetime is a key performance parameter of storage rings. DC current transformers (DCCT) are common employed to measure beam lifetime, which can only be applied to measure average lifetime. However, the physical lifetime formula is only strictly established for a single bunch. In order to provides a toolkit for complete and accurate representation of the behavior of all electron bunches, a bunch-by-bunch beam lifetime measurement system has been developed at the Shanghai Synchrotron Radiation Facility. A beam-position-monitor was used as the detector of beam-charge-monitor. Several effective techniques have been introduced to improve the resolution and data refresh rate of the single bunch charge measurement. Resolution of the new bunch-by-bunch charge monitor is better than 0.02% and data refresh rate is 140 Hz. A dedicated algorithm has been developed to extract lifetime of single bunch. Resolution of bunch-by-bunch vacuum lifetime measurement is 1 h. System setup, experiments and data analysis are presented in this paper.