FAST POLARIZATION SWITCHING AT THE SLS MICROSPECTROSCOPY BEAMLINE POLLUX

PolLux is a new microspectroscopy facility which will be operated at a bending magnet at the Swiss Light Source (SLS). It offers spectroscopy with sub-μm spatial resolution for polymer science and magnetism. First user operation is scheduled for summer 2006. One of the novel envisaged options of the beamline is the usage of circular polarized light. The circular polarization will be generated by a localized angular vertical steering of the electron beam within the bending magnet. This is accomplished by means of the global fast orbit feedback system of the SLS which allows to stabilize the electron beam to the sub-μm level up to frequencies of ≈100 Hz. Due to the adapting coupling compensation involving dedicated adjacent skew quadrupoles, this steering becomes practically transparent to the other beamlines. Polarization switching rates of a few Hz are within reach.