Two dimensional high energy x-ray powder diffraction
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Date
2006-12-04
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Australian Institute of Physics
Abstract
High-energy synchrotron radiation (around 100 keV) combined with a two-dimensional detector boasts the advantage of high penetration power for bulk studies of materials and simple setup geometries. Typically, the diffraction pattern is obtained for a several millimeter thick sample using a transmission geometry setup and the resulting concentric Debye-Scherrer rings are recorded on a flat detector.
The radii of the rings and their intensities reflect the structure and phase composition of the sample and the ring morphology can be evaluated, revealing grain statistics. Grain correlations across phase boundaries or domain relations can also be identified and sometimes a local reciprocal lattice of a crystallite can be mapped. Furthermore, anisotropies in intensity and ring radius reveal texture and lattice strain, respectively.
Data acquisition times for these patterns range from below a second to few minutes, allowing for in-situ registration during temperature cycles, resulting in a huge amount of individual diffraction patterns which have to be evaluated. As a result, algorithms need to be scripted to automate and batch-process the data evaluation. Currently code is being written in SCILAB, a public available software package, to extract the 1D pattern and other parameters for further analysis with greater efficiency. This method can also be extended to the study of many other processes; such as thermo-mechanical deformation in light metals, like titanium aluminides, magnesium, oxidation layers from steel processing and amorphous materials to mention a few.
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Keywords
Physics, Synchrotron radiation, Power, Materials, Diffraction, Geometry, Debye-Scherrer method, Rings
Citation
Yeoh, L., Liss, K. D., Buslaps, T. (2006). Two dimensional high energy x-ray powder diffraction. Paper presented at the Australian Institute of Physics 17th National Congress 2006, Brisbane Convention and Exhibition Centre, Brisbane Australia, Sunday 3 - Friday 8 December 2006. Retrieved from: https://www.aip.org.au/resources/Documents/Congress/AIPCongress-2006-Program.pdf