Editorial

Beam halo measurements and collimations are of great importance at the European XFEL, especially for the operation at high repetition rates (27000 pulses/s). First beam halo measurements have been performed during the commissioning using the wire scanners installed before and after the ~200 m long post-linac collimation section. We present the measurement results and the comparison of beam halo distributions before and after the collimation section

Beam Energy Management and RF Failure Compensation Scenarios for the European XFEL

The operation of complex systems as the driver linacs for free-electron-lasers is limited by the reliability of the individual components. Failures of RF systems can therefore constrict FEL availability. Typically reserves are included in the overall linac voltage capacity to allow for redistribution of acceleration in case of an RF failure. However, such redistributions of the acceleration of the linac affects the beam dynamics of the machine. While the effects on the optics can easily be compensated by rescaling of the quadrupole magnet strength, the bunch compression set-up requires a more involved investigation. In this paper we discuss studies for an energy management system for the European XFEL

European XFEL Injector Commissioning

In the first commissioning phase of the European XFEL SASE FEL driver linac we demonstrated the design goals for the injector section.These goals include reliable operation of sub-systems and feasible beam parameters like emittance and bunch length of the beam produced at the RF gun. Of particular interest is the operation of long bunch trains with up to 2700 bunches with a 4.5 MHz repetition rate.In this poster we will present an overview of our experiences from the injector commissioning run including beam dynamics studies, diagnostics, and system performance

Electron Beam Phase Space Tomographie at the European XFEL Injector

Transverse emittances as well as the energy spread and the peak current of the electron bunches are important parameters for high-gain free electron lasers such as the European XFEL. Investigations of the 6D phase space characterization would give important indications to optimize the beam quality for SASE operation. The injector of the European XFEL includes, inter alia, a laser heater, a transverse deflecting cavity (TDS), a spectrometer, a diagnostic section with four screens as well as several quadrupole magnets. In this paper, we will discuss the possibilities to characterize the 6D phase space of the electron beam in the injector of the European XFEL