Dual-Sweep Streak Camera Measurements of the APS User Beams

The diverse user community of the Advanced Photon Source (APS) has now evolved to include those who use the time structure of the APS x-ray beams. The APS normally runs with a 24-singlets fill, a hybrid fill with a singlet and eight septuplets, or a 324-singlet fill pattern. In all cases the total stored beam current is 100 mA, with the lattice providing a natural emittance of about 2.5 nm rad. The first two patterns are used with a top-up mode that involves injection of one pulse of ∼2.5 nC every two minutes into the designated storage ring (SR) bucket. Dual-sweep streak camera measurements (Hamamatsu model C5680) have been performed to characterize the individual and average bunch lengths in the fill patterns. The bunch lengths vary from 25 ps (sigma) in the 324-singlets fill to 50 ps (sigma) when the singlet in the hybrid fill has 7.5 mA. Example streak images of each pattern as well as a development mode will be presented and discussed.