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

<strong>Tecnai</strong> on-line help Options 77Options Software version 2This procedure provides the program with the necessary data to transform a diffraction shift (orientationand value) to a tilt (direction and value).A suitable specimen for the procedure is one that will show strong Kikuchi bands and one that isn't bent(bending of the specimen will change the apparent tilt of the specimen and thus lead to an incorrectcalibration). The silicon substrate of semiconductor specimens (somewhat thicker areas tend to showgood Kikuchi bands and are also usually straight, unlike the thin edge) has been found to be quite good.5.9 Full (zone axis) tiltThe displacement of the diffraction pattern is a measure of tilt. By centering a feature in the diffractionpattern on the viewing screen with the diffraction shift the software can convert the tilts required to bringthe particular feature (e.g. the center of a zone axis) to the screen center. In the case of Full tilt, the tiltsare set in such a way that the particular feature is centered fully.Sequence of diffraction patterns outlining the Full tilt method:Starting point is a pattern where a zone axis is clearly recognisable (atthe intersection of the Kikuchi bands) but off-center. The center of theviewing screen is marked by the black cross.Next the pattern has been shifted with the diffraction shift so now thezone axis has been centered on the screen. The center of the viewingscreen is marked by the black cross.The displacement necessary to center the pattern is then translated intotilts and the displacement is reset to zero and as a result the zone axisis now centered. The center of the viewing screen is marked by theblack cross.