Scanning electron microscope settings for EBSD
The SEM conditions used to collect your EBSD data depend upon the resolution of your SEM, phases of interest, desired speed of data collection and desired quality of data collection. A high beam current is required creating a beam spot size from 0.02µm (or slightly less) to 0.5µm in diameter (to match the material-specific resolution limits of EBSD) at a medium working distance (normally defined by the attachment position of the EBSD camera system and the geometrical requirements between the sample, electron gun and camera) using accelerating voltages between 10kV and 30kV with most systems being run using 20kV (Schwarzer et al., 2009). EBSD utilises a geometry of 70° between the incident beam and the sample, which produces the best EBSP. EBSD can be performed where this geometry cannot be achieved (such as the sample stage can only be tilted to 60°) but the quality of the patterns will be reduced. The beam current is controlled by the chosen aperture size and the beam current used will vary depending upon the phase of interest and what speed of mapping is required. A high beam current (2-10nA) can be used if mapping very quickly (30-40 points per second in quartz or 300 points per second in brass for example) as the beam is not in one place long enough to cause unacceptable amounts of damage, but if running more slowly (3-6 points per second) the beam current used must be considerably lower (0.6nA).