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Multigrain indexing of unknown multiphase materials
A multigrain indexing algorithm for use with samples comprising an arbitrary number of known or unknown phases is presented. No a priori crystallographic knowledge is required. The algorithm applies to data acquired with a monochromatic beam and a conventional two-dimensional detector for diffractio...
Autores principales: | , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
International Union of Crystallography
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4815876/ https://www.ncbi.nlm.nih.gov/pubmed/27047308 http://dx.doi.org/10.1107/S1600576716003691 |
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author | Wejdemann, Christian Poulsen, Henning Friis |
author_facet | Wejdemann, Christian Poulsen, Henning Friis |
author_sort | Wejdemann, Christian |
collection | PubMed |
description | A multigrain indexing algorithm for use with samples comprising an arbitrary number of known or unknown phases is presented. No a priori crystallographic knowledge is required. The algorithm applies to data acquired with a monochromatic beam and a conventional two-dimensional detector for diffraction. Initially, candidate grains are found by searching for crystallographic planes, using a Dirac comb convoluted with a box function as a filter. Next, candidate grains are validated and the unit cell is optimized. The algorithm is validated by simulations. Simulations of 500 cementite grains and ∼100 reflections per grain resulted in 99.2% of all grains being indexed correctly and 99.5% of the reflections becoming associated with the right grain. Simulations with 200 grains associated with four mineral phases and 50–700 reflections per grain resulted in 99.9% of all grains being indexed correctly and 99.9% of the reflections becoming associated with the right grain. The main limitation is in terms of overlap of diffraction spots and computing time. Potential areas of use include three-dimensional grain mapping, structural solution and refinement studies of complex samples, and studies of dilute phases. |
format | Online Article Text |
id | pubmed-4815876 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | International Union of Crystallography |
record_format | MEDLINE/PubMed |
spelling | pubmed-48158762016-04-04 Multigrain indexing of unknown multiphase materials Wejdemann, Christian Poulsen, Henning Friis J Appl Crystallogr Research Papers A multigrain indexing algorithm for use with samples comprising an arbitrary number of known or unknown phases is presented. No a priori crystallographic knowledge is required. The algorithm applies to data acquired with a monochromatic beam and a conventional two-dimensional detector for diffraction. Initially, candidate grains are found by searching for crystallographic planes, using a Dirac comb convoluted with a box function as a filter. Next, candidate grains are validated and the unit cell is optimized. The algorithm is validated by simulations. Simulations of 500 cementite grains and ∼100 reflections per grain resulted in 99.2% of all grains being indexed correctly and 99.5% of the reflections becoming associated with the right grain. Simulations with 200 grains associated with four mineral phases and 50–700 reflections per grain resulted in 99.9% of all grains being indexed correctly and 99.9% of the reflections becoming associated with the right grain. The main limitation is in terms of overlap of diffraction spots and computing time. Potential areas of use include three-dimensional grain mapping, structural solution and refinement studies of complex samples, and studies of dilute phases. International Union of Crystallography 2016-03-24 /pmc/articles/PMC4815876/ /pubmed/27047308 http://dx.doi.org/10.1107/S1600576716003691 Text en © Wejdemann and Poulsen 2016 http://creativecommons.org/licenses/by/2.0/uk/ This is an open-access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited. |
spellingShingle | Research Papers Wejdemann, Christian Poulsen, Henning Friis Multigrain indexing of unknown multiphase materials |
title | Multigrain indexing of unknown multiphase materials |
title_full | Multigrain indexing of unknown multiphase materials |
title_fullStr | Multigrain indexing of unknown multiphase materials |
title_full_unstemmed | Multigrain indexing of unknown multiphase materials |
title_short | Multigrain indexing of unknown multiphase materials |
title_sort | multigrain indexing of unknown multiphase materials |
topic | Research Papers |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4815876/ https://www.ncbi.nlm.nih.gov/pubmed/27047308 http://dx.doi.org/10.1107/S1600576716003691 |
work_keys_str_mv | AT wejdemannchristian multigrainindexingofunknownmultiphasematerials AT poulsenhenningfriis multigrainindexingofunknownmultiphasematerials |