Monitoring the charge bunch-by-bunch for the SSRF storage ring： Development and application

Bunch charge uniformity controlling is very important for top-up operation of the storage ring.In order to monitor filling pattern and measure the bunch charge precisely,a PXI waveform digitizer-based data acquisition system has been developed to retrieve bunch charge information from BPM pickup signals.An effective sampling rate is extended to 400 GHz by waveform rebuilding technology,which overlays multi-turn data into single turn with real time sampling rate of 8 GHz.An on-line evaluation indicates that resolution and linearity of the charge measurement are better than 0.5% at input range of 0.5-12nC.