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Exotic X‐ray back‐diffraction: a path toward a soft inelastic X‐ray scattering spectrometer
Author(s) -
Hönnicke Marcelo Goncalves,
Conley Raymond,
Cusatis Cesar,
Kakuno Edson Massayuki,
Zhou Juan,
Bouet Nathalie,
Marques Joao Basso,
Vicentin Flavio Cesar
Publication year - 2014
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576714018147
Subject(s) - diffraction , monochromator , beamline , optics , scattering , physics , resolution (logic) , x ray , spectrometer , beam (structure) , x ray crystallography , synchrotron , inelastic scattering , diffraction topography , dynamical theory of diffraction , materials science , diffraction grating , acousto optics , wavelength , artificial intelligence , computer science
In this work, soft X‐ray back‐diffraction (XBD; X‐ray diffraction at angles near and exactly equal to 90°) is explored. The experiment was conducted at the SXS beamline at Laboratorio Nacional de Luz Sincrotron, Brazil, at ∼3.2 keV. A high‐resolution Si(220) multi‐bounce back‐diffraction monochromator was designed and constructed for this experiment. An ultra‐thin Si(220) crystal (5 µm thick) was used as the sample. This ultra‐thin crystal was characterized by profilometry, rocking‐curve measurements and X‐ray topography prior to the XBD measurements. It is shown that the measured forward‐diffracted beam (o‐beam) profiles, taken at different temperatures, are in close agreement with profiles predicted by the extended dynamical theory of X‐ray diffraction, with the absence of multiple‐beam diffraction (MBD). This is an important result for future studies on the basic properties of back‐diffracted X‐ray beams at energies slightly above the exact XBD condition (extreme condition where XBD is almost extinguished). Also, the results presented here indicate that stressed crystals behave like ideal strain‐free crystals when used for low‐energy XBD. This is mainly due to the large widths of XBD profiles, which lead to a low strain sensitivity in the detection of defects. This result opens up new possibilities for mounting spherical analyzers without degrading the energy resolution, at least for low energies. This is a path that may be used to construct a soft inelastic X‐ray scattering spectrometer where different applications such as element‐specific magnetic imaging tools could be explored.