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

<strong>Tecnai</strong> on-line help Options 76Options Software version 25.6.5 Help menuThe Help menu contains two items, Show and About. Selecting Show (or pressing F1) will display thisHelp file in the <strong>Tecnai</strong> User Interface. About will display the About TEM Smart Tilt dialog listing thecurrent version number of the software. When reporting bugs, always include the version number in thereport.5.7 Camera length calibrationThe rotation calibration consists of a simple procedure to determine the orientation of the diffractionpattern relative to the viewing screen. The procedure for a single camera length consists of two steps. Inthe first step, the diffraction pattern must be centered accurately on the screen with the Multifunction X,Yknobs. Once that is done the following dialog appears.The central beam in the diffraction pattern must now be shifted to the marker indicated (or as far aspossible in the direction of the marker). Note that the distance shifted is not relevant, it is the directionthat is important.In the procedure for all camera lengths, the software goes through the same procedure for all cameralengths.5.8 Alpha and beta tilt calibrationIn order for the program to display the orientation of the tilt axes on the screen and determine the tiltsrequired when the diffraction shift is used, it is necessary to calibrate the tilt axes. In these procedures(unlike the rotation calibration), it is not only the direction that is important but also the magnitude of theshift.The tilt calibration procedure consists of the following steps (all executed after instructions from theprogram):• Tilt a crystal to a zone axis that is well-defined and will be recognisable from the Kikuchi pattern evenwhen tilted off axis.• Center the diffraction pattern accurately.• Tilt the zone axis away as far as possible (the higher the tilt away from zone axis, the more accuratethe calibration will be) with one tilt axis only, while still being able to recognise it.• With the diffraction shift recenter the zone axis (the intersection of the Kikuchi bands) on the screen.