The free-electron laser FLASH provides scientists from all over the world with ultra-short pulses of high-intensity radiation in the extreme ultraviolet and soft x-ray range. FLASH was the first free-electron laser (FEL) in the world to achieve such short wavelengths.

With its superconducting linear accelerator, FLASH is at the same time a pioneer of this accelerator technology, which is being used both for the European XFEL in the greater metropolitan region of Hamburg and for the new free-electron laser LCLS-II, currently under construction in Stanford (USA).

Important and fundamental experiments have been carried out at FLASH, offering a glimpse of the “molecular cinema” of the nanocosm. The slots for doing experiments at FLASH are highly coveted, so DESY is already making plans for the future of this facility, which belongs to the latest generation of x-ray sources in the world.

A 300-metre long free-electron laser, going by the name FLASH2020, is currently being developed as a long-term perspective. One of the key goals will be to optimise the linear accelerator so that it can produce a hundred times more x-ray pulses with a uniform pulse separation. To achieve this, the number of superconducting accelerator modules will have to be doubled, among other things. FLASH2020 will have two free-electron laser beams operating simultaneously, which will supply ultra-short pulsed x-ray radiation to several measuring stations each, independently of each other. The future operation of additional beams is in principle also possible.

Snapshots in rapid succession

A more rapid succession of x-ray pulses, meaning a larger number of pulses per second, will allow researchers to study dynamic processes in materials and chemical reactions that are not yet accessible today. FLASH2020 will open up excellent opportunities for studying the structure, function and dynamics of matter on an atomic scale with high pulse rates in the range of femtoseconds, i.e. quadrillionths of a second. Scientists will be able to examine the fundamental interactions between light and matter over time, observing crucial transition states in biochemical and catalytic reactions and watching the light-induced control of high-temperature superconductors or ultrafast magnetic switching behaviour. The growth of nanoparticles can also be observed in situ, as can the movements of biomolecules.

The existing FLASH facility could be expanded as of 2020, and the new FLASH2020 would be able to offer scientists outstanding experimental conditions for a period of 15 years.