Commissioning Results from the Bessy II Femtoslicing Source

At the BESSY II storage ring, a femtosecond x-ray source with tunable polarization and excellent signal-to-background ratio has been constructed and commissioned in 2004. This source is based on laser-induced energy modulation (” femtoslicing”) and subsequent angular separation of the short-pulse x-rays emitted by an elliptical undulator.