Experimental verification and analysis of the beam loading effect based on precise bunch-by-bunch 3D position measurement

The beam loading effect is one of the main bottlenecks in further improving the performance of synchrotron radiation light sources. Although theoretical analysis and numerical simulation of the beam loading effect have been very well performed, the corresponding diagnostic tools were rather poor, and in most cases, only streak cameras were used to observe the synchronous phase distribution and the intensity distribution in bunch trains. SSRF developed a precise bunch-by-bunch 3D beam position measurement system. This system allows precise measurement and recording of both transient state data and steady-state beam parameters (filling pattern, synchronous phase). Therefore, experimental verification and analysis of the beam loading effect can be more comprehensive and accurate. In this paper, the measurement results of the synchronous phase, synchrotron frequency and synchrotron damping time with and without a third harmonic cavity are introduced and discussed.