23.08.2012

DESY extends X-ray laser FLASH – Start of construction work for FLASH II main tunnel

DESY’s X-ray laser FLASH doubles its research capacities: only recently, construction of the FLASH II extension has started with the main tunnel section. Next year, in this 110-metre-long tunnel, the technical system for a second X-ray laser beam will be installed to serve a second experimental hall. The first ground breaking is planned to take place already this year.

Construction site of the FLASH II main tunnel.

With the help of a particle accelerator, the free-electron laser in Hamburg (FLASH) generates tightly collimated soft X-ray radiation. In the already existing accelerator, electrons are brought to almost the speed of light. Subsequently, the fast elementary particles take a slalom run through a periodic array of magnets, the so-called undulator line. In each curve, the electrons emit energy-rich light (in this case X-ray radiation), amplifying as in a conventional laser.

This unique light is in high demand among scientists. With the X-ray laser, it is possible to take snapshots of the world of molecules and photograph ultrafast processes in the nanocosm. The existing FLASH measuring stations are completely overbooked. With FLASH II, DESY will not only extend the number of measuring stations, the facility will also become more flexible. FLASH II will allow to change the wavelength of the emitted light during operation; currently, this is not possible at the existing laser beam.

In order to keep research operation mostly undisturbed, the construction of the extension tunnel was subdivided into three sections. The front section - the connection to the existing FLASH accelerator tunnel – is already completed. At the rear end, the tunnel crosses DESY’s accelerator ring PETRA III which must also run mostly undisturbed. The rear tunnel sector which connects the future experimental hall has been completed as well.

Currently, the main sector of the tunnel is being built. A webcam allows to watch the construction progress at any time. The main tunnel also includes two new buildings with technical installations for operation and research. There are already plans providing a further expansion in the future. The 15-metre-wide and 9-metre-high tunnel offers enough space for an optional third undulator line.

More about FLASH: http://www.desy.de/research/facilities/flash/index_eng.html
Construction site webcam: http://zitwebcast2.desy.de/flash2/aktuell.jpg