• B. Keil, A. Citterio, M.M. Dehler, R. Ditter, V. Schlott, L. Schulz, D.M. Treyer
  PSI, Villigen

This paper introduces the architecture and first beam commissioning results of the standard BPM system for the SwissFEL test injector, a 250MeV linac that is progressively being commissioned in order to perform R&D for the "SwissFEL" 5.8GeV hard-X-ray FEL facility proposed at PSI. Since the SwissFEL has a nominal bunch charge range of 10-200pC, the test injector is equipped with 500MHz resonant stripline BPMs that are optimized for high dynamic range and sensitivity, to support machine operation well below 10pC. Beam tests with a 5 GSa/s direct sampling electronics designed at PSI showed a single-bunch resolution of <20um RMS at 2pC and typically 7um RMS for charges >10pC. The BPMs also measure bunch charge, insensitively to dark current, with <30fC RMS resolution at 2pC.