![]() The FEL works in the so-called Self-Amplified Spontaneous Emission (SASE) mode without needing an external input signal. The lasing process is initiated by the spontaneous undulator radiation. Today, the sFLASH experiment concentrates under the new name Xseed on the preparation of external seeding in the frame work of the FLASH2020+ project.įLASH is a high-gain free-electron laser (FEL) which achieves laser amplification and saturation within a single pass of the electronīunches through a long undulator section. This is advantageous for certain classes of experiments, where a small bandwidth is required. The advantage compared to SASE is the narrow bandwidth of the radiation pulses. This radiation is overlapped with electron bunch and seeds the amplification process in the undulators. An external femtosecond short laser pulse is focused into a gas cell producing higher harmonics of the laser wavelength. The seed source was radiation from high harmonic generation (HHG). In April 2012, first seeding at 38 nm has been obtained. The FLASH1 beamline has a section equipped with variable gap undulators for seeding experiments ( sFLASH). Note, that the exact values depend on pulse length and wavelength chosen. Parameters of the THz radiation at FLASH. Therefore, both pulses, the soft X-ray and THz are perfectly synchronized (better than 5 femtoseconds). The THz pulses are produced by the same electron bunch than the SASE radiation. Not all combinations within the parameter ranges given are possible.įLASH1 is equipped with an electro-magnetic undulator able to produce Terahertz (THz) radiation pulses. Note, that exact values depend on various conditions. ![]() The unit for brilliance is B=photons/s/mrad 2/mm 2/0.1%bw. This plays an important role especially for biological samples, because carbon atoms in these samples are highly opaque to the X-ray radiation, while the surrounding water is transparent and therefore not disturbing.Ī selection of FLASH electron beam and photon pulse parameters. This opens up the possibility to investigate samples in an aqueous solution. In the water window, water is transparent to light, i.e. The water window is a wavelength region between 2.3 and 4.4 nanometers. So far this was only possible at FLASH with the third and fifth harmonic of the fundamental wavelength, which are by a factor of thousand fainter. For the first time FLASH has generated soft X-ray FEL radiation in the so-called water window. With this energy, soft X-rays with a fundamental wavelength of 4.1 nm could be produced. Right after the installation of the seventh module in 2010, the FLASH team accelerated an electron beam to an energy of 1.25 GeV. This makes a superconducting accelerator very efficient. At this temperature - just 2 degrees Celsius above the absolute zero -, niobium is superconducting so that the acceleration field can be applied with very small losses. The cavities are made of solid niobium and are cooled by liquid helium down to 2 K. Each module contains eight 1 meter long superconducting accelerating cavities operated a radio frequency of 1.3 GHz. The FLASH accelerator is equipped with seven 12 m long TESLA-type superconducting accelerating modules. Seven modules are installed, each module has a length of 12 m.įLASH: from the extreme ultra-violet to the water window Note: The whole facility has not been shutdown, parts of the accelerator, injector and seed lasers, experimental halls and other associated labs are still in operation and require the usual resources and attention.įLASH superconducting accelerating modules. Exchange of plasma chamber, exchange extraction dipole Insert an Afterburner undulator to produce circular polarized SASE at short wavelengths New layout of 2nd bunch compressor to allow optics matching and better performance in terms of beam dynamics ![]() Include a Laser Heater into the first bunch compressor Modifications for 0.5 bar operation and other refurbishments Upgrade waveguides system to optimize RF power distribution Exchange two superconducting modules with significantly better performance You may also download a free trial version from the below links:įlash Optimizer manages to reduce your SWF files size up to 60-70% thanks to amazing algorithms of vectors, shapes, morphing, Z-buffer, fonts and other optimizations.Accelerating module PXM2.1 installed into the FLASH injector. ![]() Please wait, the server is connecting to Flash Optimizer online ordering page. If you are not connected to the online ordering page automatically in 10 seconds, please click the
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