An ultrahigh-vacuum apparatus for resonant diffraction experiments using soft x rays (h=300-2000 eV)

Abstract

We have developed an ultrahigh-vacuum instrument for resonant diffraction experiments using polarized soft x rays in the energy range of h=300-2000 eV at beamline BL17SU of SPring-8. The diffractometer consists of modified differentially pumped rotary feedthroughs for θ-2θ stages, a sample manipulator with motor-controlled x-y-z -, tilt () -, and azimuth (φ) -axes, and a liquid helium flow-type cryostat for temperature dependent measurements between 30 and 300 K. Test results indicate that the diffractometer exhibits high reproducibility (better than 0.001°) for a Bragg reflection of α -quartz 100 at a photon energy of h=1950 eV. Typical off- and on-resonance Bragg reflections in the energy range of 530-1950 eV could be measured using the apparatus. The results show that x-ray diffraction experiments with energy-, azimuth-, and incident photon polarization-dependence can be reliably measured using soft x rays in the energy range of ∼300-2000 eV. The facility can be used for resonant diffraction experiments across the L -edge of transition metals, M -edge of lanthanides, and up to the Si K -edge of materials. © 2009 American Institute of Physics.