Experience with Multi-Beam and Multi-Beamline FEL-Operation

DESY’s free-electron laser FLASH provides soft X-ray pulses for scientific usersat wavelengths down to 4 nm simultaneously in two undulator beamlines. They are drivenby a common linear superconducting accelerator with a beam energy of up to 1.25 GeV. Thesuperconducting technology allows the acceleration of electron bunch trains of several hundredbunches with a spacing of 1 microsecond or more and a repetition rate of 10Hz. A fast kickerseptumsystem directs one part of the bunch train to FLASH1 and the other part to FLASH2keeping the full 10Hz repetition rate for both. The unique setup of FLASH allows independentFEL pulse parameters for both beamlines. In April 2016, simultaneous operation of FLASH1and FLASH2 for external users started. This paper reports on our operating experience withthis type of multi-beam, multi-beamline set-up