TexPat – a program for quantitative analysis of oblique texture electron diffraction patterns

Abstract

We have developed a program – TexPat for quantification of texture patterns in order to facilitate, speed up and improve the accuracy of this analytical method. The program introduces new approaches for automated detection of centre and symmetry axes and simplifies the process of indexing and calculating the unit cell parameters. The main algorithm of the program uses the symmetry properties of the texture pattern images. The successive steps help to process the reflections of the pattern using the peak shape extracted from well-separated peaks. The program generates a list of unit cell parameters, all processed reflections with Miller indices and their integrated intensities. The quality of the results obtained by TexPat is compatible with published data.

PCED2.0—A computer program for the simulation of polycrystalline electron diffraction pattern

“…This technique is especially important to study the crystalline structure of textured samples since more diffraction data can be recorded in the electron diffraction patterns [19]. A program for extracting diffraction data from experimental pattern should include such a function.…”

Electron powder diffraction

“…The Russian crystallography group developed the theory of arcs in oblique texture and used such textured patterns in structure analysis (Vainshtein, 1964;Vainshtein & Zvyagin, 1992). The TexPat software (Oleynikov & Hovmoller, 2004) was designed and effectively applied to determining unitcell parameters and refining structure from oblique textured electron diffraction patterns. Tang et al (1996) developed a method to determine the axis of texture and distribution of directions around that axis.…”

Comparison of intensities from glass photo plates and imaging plates

“…The main problems arising during the quantification of texture patterns are overlapping reflections especially for low symmetries (see figure for example) and complications with intensities extraction. In order to solve these problems a two-dimensional pattern decomposition method was developed and implemented in the program TexPat [2]. It allows refining of different parameters simultaneously.…”

“…A series of multiply exposure of oblique texture electron diffraction pattern of brucite mineral Mg(OH) 2 , recorded on glass photo plates, were processed by means of TexPat software [1]. Intensities were estimated as profile areas across arc reflections passing through their centers.…”

“…In the case of partial overlapping, the reflections could be separated. The structure amplitudes were calculated from intensities according to their local values |Fhkl|= ÖIobs/dhkldhk0p, where indices hkl and hk0 are related to the one and the same ellipsis, and p is the multiplicity factor [2]. The intensities of reflections coinciding in texture patterns were subdivided proportional to corresponding |Fhkl| 2 values.…”