FLASH at DESY is a single-pass FEL based on the concept of self-amplified spontaneous emission (SASE). It employs a 1 GeV superconducting linear accelerator and a 30 m long, fixed-gap planar undulator, covering a wavelength range of ~50 nm (25 eV) to 6.5 nm (190 eV). The single FEL beam can be switched to five experimental stations by mirrors. Intense, coherent THz pulses from a special undulator and a femtosecond optical laser system are available for pump-probe experiments. FLASH has been in operation for user experiments since 2005.
FERMI@Elettra is a single-pass FEL user-facility covering the wavelength range from 100 nm (12 eV) to 10 nm (124 eV), located next to the third-generation synchrotron radiation facility ELETTRA in Trieste, Italy. The advent of femtosecond lasers has revolutionized many areas of science from solid state physics to biology. This new research frontier of ultra-fast VUV and X-ray science drives the development of a novel source for the generation of femtosecond pulses.
MAX IV is planned to be the next generation Swedish synchrotron radiation facility. It will replace the existing facility consisting of the MAX I, II and III storage rings. MAX IV will contain two storage rings in the same complex: a 3-GeV ring for the production of hard x-rays and a 1.5 GeV ring for the production of vacuum ultraviolet (VUV)) radiation and soft x-rays. In addition the MAX III ring will be reinstalled at the new locations. This solution allows the production of synchrotron radiation with optimal characteristics in a wide energy region, fulfilling the needs of most diverse research areas. The MAX IV design also includes an option for the generation of coherent radiation by a cascaded optical klystron planned in connection with the injection system for the storage rings.
In 2007, the UK Science and Technology Facilities Council (STFC) embarked on a project to examine the case for a New Light Source (NLS) facility based on advanced conventional lasers closely synchronised to free electron lasers. In July 2009 an updated Science Case was published along with the Outline Facility Design. The specified high repetition rate (1kHz baseline) required super-conducting linac technology to generate bunches of 2.25 GeV electrons. The bunches could be directed into three parallel soft X-ray FELs, which together covered the photon energy range from 50 eV to 1 keV in the first harmonic . The FELs would be seeded using HHG sources, allowing the generation of short (20fs) photon pulses. However, as a result of STFC‘s Science Programme Prioritisation (published in December 2009) it was announced that, at this stage, it would not be possible to continue the project beyond April 2010. The case will be reviewed in 3 – 5 years and hence the current phase of the NLS project will end in April 2010 with the completion of the detailed Conceptual Design Report.
The free electron laser project SPARX (Sorgente Pulsata Autoamplificata di Radiazione X) aims at realizing a large scale ultra-brilliant and coherent X-ray source in Italy. It will produce ultra-short X-ray pulses of 1-100 fs duration and cover the spectral range between 1 to 10 nm.
The PSI XFEL project intends to exploit novel concepts for electron emission, high gradient acceleration and effective bunch compression to construct an XFEL user-facility at only a fraction of the present costs. Based on a normal-conducting 6 GeV linear accelerator, the XFEL will cover a spectral range of 0.1-10 nm wavelength.
The proposed Polish Free Electron Laser is a fourth generation light source driven by a 600 MeV superconducting linear accelerator in CW (continuous wave) mode. It will cover the VUV range down to <30 nm with its fundamental wavelength and to below 10 nm using higher harmonics.
SOLEIL prepares for the future with ARC-EN-CIEL (Accelerator-Radiation Complex for Enhanced Coherent Intense Extended Light), a fourth generation light source project combining the ultimate Free Electron Lasers seeded by High Harmonics Generation in gas in the VUV-soft X ray domain, undulators in spontaneous emission for hard X-rays at 2 GeV electron beam energy and for VUV light and soft X-rays at 1 GeV on two ERL loops, and a FEL oscillator in the Extreme Ultra Violet (EUV) region.