SSRF Operates in Top-Up Mode
Since December 6，2012, the Shanghai Synchrotron Radiation Facility (SSRF) has operated in top-up mode for user experiments, which was a milestone of SSRF in facility performance improvements. Until December 18 at 9:00 am, SSRF has successfully completed the first round of the top-up operation. In top-up mode, the stored beam has been maintained at 201±0.5 mA. The top-up injections are made continuously at the time interval of about 10 minutes. Each injection cycle takes about 10 seconds and the bunch change uniformity in the 500 bunch train is better than 95%. The machine availability of SSRF is 99.5%. The stability of beam orbit at both ends of insertion devices in the storage ring are 0.56 μm（rms） and 0.25 μm（rms） in horizontal and vertical plane respectively in 12 days. During the first two weeks of top-up operation, 86 experiments were carried out by 206 users from 47 different institutions and universities. Users were satisfied with the stable beam and better experimental results were achieved during the top-up operation.
Figure 1: The SSRF operation status.
Figure 2: The Top-Up injection control interface.