Tecnai on-line help manual -- Options - UT Southwestern

<strong>Tecnai</strong> on-line help Options 86Options Software version 27 TEM k-Space Control (FP5453/00)7.1 IntroductionTEM k-Space Control is software that uses an input set of crystal-lattice parameters and lattice type to• Create a stereographic projection of the crystal’s zone axes• Simulate the electron diffraction patterns and Kikuchi lines that would be seen in the TEM when thecrystal is tilted to various orientations.The Kikuchi- and diffraction-pattern simulations can aid the identification of diffraction patterns from thecrystal’s zone axes in the TEM.In conjunction with the automatic control of the CompuStage and the ability for on-line diffraction patternmeasurement of the microscope, TEM k-Space Control becomes a powerful tool for crystallographicresearch with the TEM. The orientation of the crystal can be determined with respect to the tilt axes ofthe CompuStage and the crystal can then be tilted by the software to any zone axis within the range ofthe specimen tilts.7.2 Getting startedThe TEM k-Space Control option consists of two parts:• The k-Space Control Control Panel.• The k-Space Control Display window.To use TEM k-Space Control:• Open the <strong>Tecnai</strong> Workspace layout (bottom-right selection list) and drag the k-Space Control ControlPanel into a workset.• Go to the tab of the workset and press the Display button in the k-Space Control Control Panel. Thek-Space Control window will be loaded and its functionality become available.You can leave the k-Space Control Control Panel in your workset for future use. The Display window willonly be loaded when the Display button is pressed.7.3 General introductionThe flow of working with k-Space Control falls into three separate parts:1. Definition of the crystal structure2. Determination of the orientation of the crystal3. Changing the orientation7.3.1 Definition of the crystal structureIn order for crystallographic calculations to be performed, the crystal structure (lattice parameters andtype of structure - Primitive, Face-centered, etc.) must be known. These data are entered by the user,either by typing and selecting the relevant data or by loading from an existing crystal structure file. Thecrystal structure must therefore be known beforehand (k-Space Control is NOT a tool for matchingcrystal structure from a database with data derived from diffraction on the microscope).