Application of synchrotron through-the-substrate microdiffraction to crystals in polished thin sections
Rius, Jordi (Institut de Ciència de Materials de Barcelona)
Vallcorba Valls, Oriol (ALBA Laboratori de Llum de Sincrotró)
Frontera, Carlos (Institut de Ciència de Materials de Barcelona)
Peral Alonso, Inmaculada (ALBA Laboratori de Llum de Sincrotró)
Crespi, Anna (Institut de Ciència de Materials de Barcelona)
Miravitlles Torras, Carles (Institut de Ciència de Materials de Barcelona)
Universitat Autònoma de Barcelona

Data:	2015
Resum:	The synchrotron through-the-substrate X-ray microdiffraction technique is applied to the structural study of microvolumes of randomly oriented crystals embedded in polished thin sections. The whole procedure is discussed in detail with the help of examples from petrology, and possible future developments are envisaged. The synchrotron through-the-substrate X-ray microdiffraction technique (tts-μXRD) is extended to the structural study of microvolumes of crystals embedded in polished thin sections of compact materials [Rius, Labrador, Crespi, Frontera, Vallcorba & Melgarejo (2011). J. Synchrotron Rad. 18, 891-898]. The resulting tts-μXRD procedure includes some basic steps: (i) collection of a limited number of consecutive two-dimensional patterns (frames) for each randomly oriented crystal microvolume; (ii) refinement of the metric from the one-dimensional diffraction pattern which results from circularly averaging the sum of collected frames; (iii) determination of the reciprocal lattice orientation of each randomly oriented crystal microvolume which allows assigning the hkl indices to the spots and, consequently, merging the intensities of the different frames into a single-crystal data set (frame merging); and (iv) merging of the individual crystal data sets (multicrystal merging) to produce an extended data set suitable for structure refinement/solution. Its viability for crystal structure solution by Patterson function direct methods (δ recycling) and for accurate single-crystal least-squares refinements is demonstrated with some representative examples from petrology in which different glass substrate thicknesses have been employed. The section of the crystal microvolume must be at least of the same order of magnitude as the focus of the beam (15 × 15 µm in the provided examples). Thanks to its versatility and experimental simplicity, this method­ology should be useful for disciplines as disparate as petrology, materials science and cultural heritage.
Ajuts:	Ministerio de Economía y Competitividad MAT2012-07967
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Tts-μXRD ; Polished thin sections ; Crystal microvolume ; Patterson function direct methods ; δ recycling ; Synchrotron radiation ; Two-dimensional frame merging ; Multicrystal merging ; Structure solution
Publicat a:	IUCrJ, Vol. 2, part 4 (July 2015) , p. 452-463, ISSN 2052-2525

DOI: 10.1107/S2052252515007794
PMID: 26175904

12 p, 1.3 MB

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