Parallel-slit analyzer developed for the purpose of lowering tails of diffraction profiles

Abstract

A parallel-slit analyzer (PSA) has been developed for the purpose of lowering tails in diffraction pro®les from powders and thin ®lms. In the present work, four different materials were used for the foils: sintered and hot-pressed tungsten (W), cold-worked stainless steel (SUS), beryllium bronze (Cu 98 Be 2 ) and chemically surface-processed beryllium bronze (CuOx). The PSAs were tested in a parallel-beam geometry using Cu K radiation collimated with a graded d-spacing parabolic multilayer mirror. The W and CuOx PSAs gave pseudoVoigt pro®les of $80% Gaussian in the direct-beam case. Textured and roughened surfaces of W and CuOx foils are considered effective for depressing totalre¯ection effects from the surfaces of the foil materials, and consequently for lowering the tails of diffraction peaks.

The Role of Development of the Rotating Anode X-ray Generator and the Use of Imaging Plates in Powder Diffractometer Instrumentation

“…Figure 7. Diffraction profiles of the 533 reflection of a Si powder sample obtained by parallel-beam optics at various temperatures (17 ). The profile is symmetric for parallel-beam geometry, but asymmetric for the B-B method owing to inherent aberrations.…”

“…The profile is symmetric for parallel-beam geometry, but asymmetric for the B-B method owing to inherent aberrations. Temperature dependence of two lattice parameters of an Al 2 O 3 powder sample measured by a parallel-beam method (17 ). Diffraction profiles of the 533 reflection of a Si powder sample obtained by parallel-beam optics at various temperatures (17 ).…”

“…Using this optic we can select only K α1 radiation from Cu radiation and can get a very thin parallel beam. Note that such a wide range can only be obtained by using these optics together with a 15-kW rotatinganode X-ray generator; otherwise, we could reach only the order of 10 ᎑7 (16,17 ). To measure reflectivity of thin amorphous SiO 2 film, however, a single multilayer optic is sufficient if it is combined with a multilayer analyzer.…”

Instrumental aspects in X-ray diffraction on polycrystalline materials

“…Those very high resolution devices developed at synchrotron sources have been adapted to the laboratory scale using artificial crystals made of parabolic graded multilayers. The corresponding arrangement is shown in Figure 8͑b͒ ͑Schuster and Göbel, 1996;Gross et al, 1998;Fujinawa et al, 1999͒. The conventional sealed X-ray tube is set on the focal point of a one-dimensional parabolic multilayer.…”

Kα1–Kα2characteristic of a parabolic graded multilayer

“…The powder sample used was the National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) Si 640b. Parallel slits, consisting of W foils (angular aperture 0.057 ), were used as an analyser (Fujinawa et al, 1999) together with Soller slits (angular aperture 2 ). Observed diffraction pro®les were analysed by using the computer program PROFIT (version 3.01; Toraya, 1986) for individual pro®le ®tting and modelling the pro®le shape using the pseudo-Voigt function.…”