Design and Beam Test Results of the Reentrant Cavity BPM for the European XFEL

International audienceThe European X-ray Free Electron Laser (E-XFEL) will use reentrant beam position monitors (BPMs) in about one quarter of the superconducting cryomodules. This BPM is composed of a radiofrequency (RF) reentrant cavity with 4 antennas and an RF signal processing electronics. Hybrid couplers, near the cryomodules, generate the analog sum and difference of the raw pickup signals coming from two pairs of opposite RF feedthroughs. The resulting sum (proportional to bunch charge) and difference signals (proportional to the product of position and charge) are then filtered, down-converted by an RF front-end (RFFE), digitized, and digitally processed on an FPGA board. The task of CEA/Saclay was to cover the design, fabrication and beam tests and deliver these reentrant cavity BPMs for the E-XFEL linac in collaboration with DESY and PSI. This paper gives an overview of the reentrant BPM sys-tem with focus on the last version of the RF front end electronics, signal processing, and overall system performance. Measurement results achieved with prototypes installed at the DESY FLASH2 linac and in the E-XFEL injector are presented

First Experience with the Standard Diagnostics at the European XFEL Injector

International audienceThe injector of the European XFEL is in operation since December 2015. It includes, beside the gun and the accelerating section, containing 1.3 and a 3.9 GHz accelerating module, a variety of standard diagnostics systems specially designed for this facility. With very few exceptions, all types of diagnostics systems are installed in the injector. Therefore the operation of the injector is served to validate and prove the diagnostics characteristics for the complete European XFEL. Most of the standard diagnostics has been available for the start of beam operation and showed the evidence of first beam along the beam line. In the following months the diagnostics has been optimized and used for improvements of beam quality. First operational experiences and results from the standard beam diagnostics in the injector of the European XFEL will be reported in this contribution

Status of the Standard Electron Beam Diagnostics of the EU-XFEL

Outline• Setup and status accelerator• Diagnostics• BPMs• Toroids• Beam Loss Monitors• Wirescanner• Dosimetry• Summar