Multilayer transmission phase shifters for the carbon K edge and the water window

A multilayer transmission filter with 100 periods Cr/C has been produced in order to achieve a significant phase retardation for photon energies just below the carbon K edge. The phase retardation of this device was characterized and despite being smaller than expected the filter was suitable for the polarization characterization of a soft x-ray beamline with a primary standard. Neither the filter nor the beamline were found to change their characteristics in the course of seven months. Considering the state of the art of multilayer coatings additional model calculations show that these transmission filters can be applied also at 400 eV photon energy with an upper limit at 500 eV.