SLAC

SPEAR3 provides up to 500mA circulating beam current in top-up mode. In recent years the synchrotron radiation user program has moved in the direction of laser/x-ray pump-probe experiments which utilize a single timing ‘probe’ bunch isolated by 50ns dark space ahead and behind the bunch. In order to quantify bunch purity in adjacent buckets, a time-correlated single-photon counting system has been tested. By monitoring the bunch pattern, is it possible to evaluate when the x-ray probe bunch is sufficiently isolated, and pave the way for shot-by-shot charge injection that maintains all bunches at specified current levels.