Shutdown at BESSY II: An extremely productive break

Waiting for remaoval: the old cavities. (HZB, W. Anders)

From the end of October to the middle of January, no electrons will circulate in the synchrotron ring BESSY II. “We shut down BESSY II at the beginning of the last October week, as planned,” says Dr. Christian Jung, head of the main department Scientific-Technical Infrastructure II. “We plan to carry out extensive maintenance and setup work, so we will be working on BESSY II day and night for close to three months. In mid-January 2016, the radiation source will be available once again to users – more powerful than ever.”

The bulk of the work involves changing two cavities, which are the technical units that keep electrons racing through the storage ring at near light speed. “The old cavities are long in the tooth,” says Ingo Müller, who is managing the whole affair together with Christian Jung during the shutdown. “We swapped out the first pair already in 2013. Now it’s time for the second pair.” To do this, they will have to open the inner ring – a very complicated procedure, which will take time. “We will use this time for other work,” Müller explains: “For example, we will be convert the last two high-frequency transmitters to semiconductor basis, which continuously add energy to the electrons in their circular path, and thus conclude a certain modernisation. But we still have much more to do than that.”

Experience the complexity of the works on BESSY II in our Future Logbook ZLOG! Here, we will keep you posted with instant updates on the activities during the shutdown. On Friday, 6 November 2015, we will be hosting a “photowalk” through the storage ring: A selection of amateur photographers will then document their perspective of BESSY in its shut-down state.

Hannes Schlender