A crystal monochromator for a linearly polarized X-ray source utilizing channeling radiation

The performance of a high transmission crystal monochromator to be used as part of a source of linearly polarized X-rays of moderately narrow bandwidth in the energy regime of 10–50 keV has been investigated using channeling radiation produced by 86 MeV electrons from the superconducting linear accelerator S-DALINAC at the Technische Hochschule Darmstadt. Best results on monochromatic photon yields have been obtained with cylindrically bent silicon monocrystals in Laue and with planar mosaic crystals in Bragg geometry, respectively. At energies between 20 and 30 keV monochromatized X-ray intensities of up to 1.5 × 1010photons(s sr μA) have been obtained for axial channeling radiation from a 13 μm thick silicon radiator crystal. The measured yields of narrow band X-rays are such that an intense source of highly polarized planar channeling radiation could well serve to calibrate the linear polarization sensitivity of a CCD polarimeter.