Contribution to a book

Barely two weeks after the European XFEL opened its doors to users, the first user experiment was performedby a DESY-led international team of over 120 researchers. The European XFEL is the first hard X-ray FEL in the world capable of producing femtosecond pulses at a megahertz repetition rate. [...]

Molecules are the entities defining the world around us, the building blocks of chemistry and biology. Everybody knows what a molecule is, but it’s far from trivial to define exactly what is a ‘molecule’ [...]

The self-modulation instability (SMI) of long (in respect to the plasma wavelength) charged particle beams passing through plasma enables the use of currently existing high energy charged particle beams as drivers for plasma wakefield accelerators. At the Photo Injector Test facility at DESY in Zeuthen (PITZ) the SMI of electron beams is studied *, **. [...]

The Photo Injector Test Facility at DESY in Zeuthen (PITZ) carries out studies of beam-driven plasma wakefield acceleration (PWFA). The facility possesses a flexible photocathode laser beam shaping system and a variety of diagnostics including a high-resolution dipole spectrometer and an rf deflector which enables the observation of the longitudinal phase space of electron beams after their passage through a plasma. [...]

The intrinsic slice emittance of the emitted electrons on the photocathode surface at each moment during the transient photoemission process depends on the transverse size of the slice and the mean kinetic energy of the electrons within the slice. The latter relies on the surface barrier potentials of the cathode material at a fixed wavelength of the incident light, and is thus significantly influenced by the presence of strong rf and beam self-fields at / close to the cathode surface. [...]

A CW upgrade of European XFEL is under consideration, and CW electron injector is under R at DESY. One of the injector solutions is the LCLS-II like injector based on a normal conducting CW gun and buncher. [...]

Beam driven wakefield acceleration (PWFA) schemes in plasmas are among the most promising candidates for novel, compact accelerators. Several aspects of PWFA are under investigation at the Photoinjector Test facility at DESY in Zeuthen (PITZ). [...]

The cryomodule PXFEL3_1 is one of three prototype cryomodules for the European XFEL. In preparation of the series module assembly it was used for the qualification of infrastructure and personnel at CEA Saclay. [...]

In state of the art photoinjector electron sources, cathode performance determines the lower limit of achievable beam emittance. Measuring the thermal emittance at the photocathodes in electron guns is of vital importance for improving the injectors. [...]

A free-electron laser based THz source is undergoing design studies at the Photo Injector Test facility at DESY in Zeuthen (PITZ). It is considered as a prototype for pump-probe experiments at the European XFEL, benefiting from the fact that the electron beam from the PITZ facility has an identical pulse train structure as the XFEL pulses. [...]