Beam Stoppers for SwissFEL

On the 5th of May the two beam stoppers were installed in the SwissFEL tunnel. These two blocks are made out of copper, recycled lead, steel and concrete blocks and weight 60 tons each. These stoppers are placed in front of both Aramis and Athos undulator lines. They will block the electron beam during machine adjustment or diagnostic to avoid uncontrolled beam loss in the undulator magnets. For example, when the electron beam goes through a diagnostic screen it cannot be used anymore for lasing and has to be dumped in the beam stoppers before the undulators.