Approximately 20 weeks of beamtime are provided for scientific experiments per year which are not possible on any other radiation source. It is operated in the "self-amplified spontaneous emission" (SASE) mode. Five beamlines are operational.

In the past years, an additional FEL undulator line in a separate tunnel - FLASH2- and the new 'Kai Siegbahn' experimental hall have been built adjacent to the existing FLASH facility now called FLASH1. First lasing of FLASH2 was achieved in August 2014 in parallel to FLASH1. Now, the FLASH facility at DESY comprises two separate and almost independent FEL sources. This upgrade enhances significantly the capacities for VUV and soft X-ray FEL users at DESY. Up to 6 beamlines (called FL beamlines) will be set up in the 'Kai Siegbahn' hall, FL24 and FL26 have started operation in spring 2016.

FL24 has an open port for user supplied endstations. FL24 covers the entire wavelength range of FLASH2. It offers a KB bending mirror system and a split-and-delay unit for XUV-XUV pump-probe experiments.

FL26 features the permanent end station REMI - a reaction microscope from R. Moshammer's group at MPIK Heidelberg.





Photon Beam Parameters
Deutsches Elektronen- Synchrotron DESY
Notkestraße 85 Hamburg
TEL. +49 40 8998-0
FAX. +49 40 8998-3282
call for proposals


No call planned until summer 2021

The regular calls for FLASH proposals in fall 2020 and spring 2021 will be skipped. This is because the present COVID-19 situation forced us to postpone and reschedule many experiments, filling the corresponding beamtime slots. Furthermore, the FLASH2020+ upgrade program to make FLASH brighter, faster and more flexible requires a first shutdown starting end of 2021, as already announced.
We plan to issue the next call for proposals for FLASH in summer 2021 with the deadline on October 1st, 2021, and relating to beamtime in the second half of 2022. We sincerely apologise for any inconveniences that may cause for your planning.
Registered DOOR users will be informed by e-mail about the call opening in 2021.




in partnership with