Soft X-ray diffractometer for synchrotron radiation

An ultra-high vacuum soft X-ray diffractometer has been constructed and com missioned at the Synchrotron Radiation Research Center (SRRC) to investigat e materials structures in mesoscale. The diffractometer, housed in a UHV ta nk, consists of a 6-circle goniometer, together with the systems for beam-c ollimation, signal detection, vacuum, and control panels. The kappa-phi-psi goniostat is adopted for the sample orientation. Crystal samples can be ro tated along a given reciprocal lattice vector by using psi scan. Two orthog onal axes,, (or 2 theta) and delta, are used to move the detector. The dete ctor is a semiconductor pin diode, which can be used in UHV ambient. This 6 -circle goniometer allows for sample scanning of a wide range in the moment um space. The motors used for goniometer rotation and slit selection are UH V compatible. The UHV tank is placed on an XYZ table capable of positioning the center of the goniometer onto the incident beam. Test experiments have been carried on the 1-9 keV double-crystal monochromator (DCM) beamline to commission the diffractometer. These include powder diffraction of standar d quartz crystals, 0-2 theta scans of zeolite thin films, specular reflecti vity of Ti2O5/SiO2/Zerdur multilayers, soft X-ray multiple diffraction of s ilicon single crystals, and the polarization effects on three-beam diffract ion. The obtained experimental results demonstrate the excellent capability of the diffractometer in characterizing both mososcopic and microscopic st ructures of matter. (C) 2001 Elsevier Science B.V. All rights reserved.