Status and commissioning-results of BESSY II

The new Storage Ring BESSY II in Berlin Germany is a dedicated third generation synchrotron radiation source for the VUV and soft X-ray spectral range. On April 22/sup nd/, 1998 a 1.7 GeV electron beam was stored for the first time. Despite a relatively short time for commissioning of the synchrotron radiation source, the milestones were met as scheduled. Accelerator parameters that determine the quality of the synchrotron radiation are as designed or the design goals were even exceeded. The only parameter that is still not according to design is the beam lifetime, as the baking of the vacuum system is not completed yet. The regular scientific program started according to plan in January 1999 with experiments. The front-end for 22 additional beamlines are installed and scheduled for use before the end of next year. Thus required shutdown periods will also be used to install additional hardware to improve the performance of the ring.