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Undertaking EBSD experiments
Spatial resolution The electrons contributing to the diffraction pattern originate within nanometres of the sample surface. Hence the spatial resolution will be related to the electron beam diameter and this depends on the type of electron source and probe current used. Typical beam diameters at 0.1 nA probe current and 20 kV accelerating voltage are 2 nm for a FEG source and 30nm for a tungsten source. The beam profile on the sample surface will also be elongated in the direction perpendicular to the tilt. The spatial resolution achieved in practice will depend on the sample, SEM operating conditions and electron source used and under optimum conditions grains as small as 10 nm can be identified.
Measurement accuracy
Orientation measurement Errors in crystal orientation measurements from the diffraction pattern will depend principally on the accuracy of the Kikuchi band position measurement and the system calibration and are generally in the range of ±0.5°. To avoid systematic errors in orientation measurements with respect to the sample axes for texture measurements, care should be taken to ensure that the sample normal and longitudinal directions are oriented correctly with respect to the phosphor screen.
Residual errors
For each orientation measurement a residual angle
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can be calculated where
is
the measured angle between the ith
pair of Kikuchi bands, 
is
the actual angle between the corresponding crystal planes and n is the
number of Kikuchi band pairs.