Resumption of full scientific operation at BESSY II delayed

the 7-Tesla Multipole Wiggler: after one year working on it, the wiggler came back from Novosibirsk as planned but had to be removed from the storage ring again. The reason for highly elevated operating temperatures are investigated.

While the lengthy summer shutdown with its comprehensive updating and maintenance work has been completed as planned, there have been some unforeseeable disruptions that will delay the resumption of regular Top-Up operations at present. The scientific operating time for users which was unavailable in October will be made up at the beginning of 2014.

Initial operation of the storage ring has been successfully commenced; however the electron source of the Linac has displayed unexpected arcing voltages. Storage ring injection has therefore been transferred from the Linac over to the Microtron. The repair work is progressing with the goal of being able to use the Linac again as soon as possible.

As long as injection is being carried out with the help of the Microtron, comprehensive operation in Top-Up mode is not possible, unfortunately, while insertion of the usual individual pulses into the gaps of multi-pulses in hybrid mode is not available.

Due to the problems with the Linac, no external scientific work could take place during the second week of October. The down-time will made up through an additional operating week at the beginning of 2014.

External scientific work with BESSY II resumed on 15 October: during the day, the storage ring will only be operated in restricted decay mode, however, while at night in reduced Top-Up mode. This assures that scientific use is available for the majority of BESSY II users.

Moreover, the 7-Tesla Multipole Wiggler, which supplies the EDDI, MAGS, and ASAXS beamlines with hard X-ray radiation, displayed highly elevated operating temperatures and had to be removed from the storage ring again. Repairs are in progress, though the Wiggler will probably only be able to come online again in December, however.

This means that external scientific work with the three beamlines mentioned above cannot take place probably until the end of the year. 
All members of the BESSY II team keenly regret these unforeseen restrictions to our users as well as our own in-house colleagues. They request your understanding and are working hard to restore comprehensive external operation again as quickly as possible.

Current information about operational status of BESSY II can be viewed on the informational systems of BESSY II in the internet at