Contents I. Introduction
Flash [1] is a R&D study exploring superconducting cavity technologies to be used by future linear accelerators and a user facility for free-electron laser experiments. During first runs the linac was operated at 0.4 GeV to produce laser like light at a wavelength of 32 nm. Wavelengths down to 6 nm are foreseen in the near future. An electron beam of 1 nC charge is accelerated by five cryogenic modules with eight cavities each (Fig. 1). The bunch length is shortened by two bunch compressors to provide the required high peak currents for self-amplified spontaneous emission (SASE) in the undulator section that produces the laser light. At the end of the linac the emitted light from the undulators is sent to experiments while the electron beam is deflected into a beam dump.
