Description of the Microscope
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MIRA3 FEG-SEM
CHANNELING Mode
In CHANNELING mode, the scanning and lens focusing is controlled so that the electron
beam touches the same point of the specimen surface all the time. By means of scanning the
beam, only the angle of incidence of the electron beam is changed, i.e. the rocking beam.
Characteristics:
the position of the specified point in the image depends
on the beam tilt
it is the mode for ECP acquisition - Electron Channeling
Pattern
The resulting image is the amount of electrons dependent on the
impacting beam angle. The excitation ratio of the scanning coils is
set up so that the beam utilizes the whole area of the objective lens
bore and enters the lens parallel to the optical axis.
All electron beams parallel to the optic axis are focused by the lens
into a single point on the specimen surface. As a consequence, the
scanning is transformed into beam tilting, i.e. the resulting pivot
point of the scanning lies on the specimen surface plane.
The intermediate lens focuses the beam into the upper focal point
of the objective lens. The result is that the beam, after passing
through the objective lens, is parallel and the angular resolution
of ECP (Electron Channeling Pattern) images is at its maximum.
The mode is intended for the examination of crystallographic
materials. In consideration of the optical abilities of the MIRA3
column, the minimum size of crystals is (100–150) µm.
Note: ECP patterns are produced by back scattered electrons, it is preferable to use a BSE
detector for imaging if available.
Summary of Contents for MIRA3
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