Accelerators 2018

is with great pleasure and honour that I report the progress that was made in 2018, under the leadership of my predecessor Reinhard Brinkmann, whom I succeeded as director of the Accelerator Division as of 1 February 2019. For the European XFEL X-ray laser, DESY continued its responsibility for operating the 2.1 km long superconducting linear accelerator driving the free-electron laser (FEL). In 2017, the accelerator complex was swiftly commissioned and the first hard X-ray self-amplified spontaneous emission (SASE) FEL beams were provided to users at the SASE1 beamline. In 2018, the SASE1 beamline performance was further improved and user experiments commenced, operation of the second and third X-ray beamlines (SASE2 and SASE3) started, and the first operation of all three sources in parallel was demonstrated. This unique feature of simultaneous operation of three beamlines and full flexibility of pulse selection “à la carte” provides the users with tremendous options for tailoring the X-ray radiation pulses to the needs of their experiments. In July 2018, after installation and commissioning of the last two radio frequency (RF) stations of the accelerator and optimisation of all 24 stations, electrons were accelerated to the design energy of 17.5 GeV. While standard operation is typically with 300 bunches per RF pulse, i.e. 3000 bunches per second, the operating team increased the beam intensity to the full design value of 27 000 bunches per second in November. Bringing such a novel, complex facility up to its design performance in such a short time is truly an amazing achievement, and is a testimony to the expertise and dedication of all the groups of DESY’s Accelerator Division joining forces with the operating teams from European XFEL. We are looking forward to exciting new science results in the coming years!