Correct Condenser Astigmatism - Hitachi HF2000 TEM Operation Manual

5. Correct condenser astigmatism（Magnification : 100K ~ 200K）
Be sure to use the correct condenser astigmatism for TEM mode:
•
Open the GV and make sure you hear it click open.
•
Turn the Brightness control (left panel) to crossover, and center the beam with the Brightness
Centering knobs (right panel).
•
Using the condenser stigmator (right sub panel) make the caustic as round or axial symmetry. And
using the 3rd order stigmator (left sub panel) makes the caustic as symmetry. The 3rd order correction
will be slight and the controls should be close to the center positions.
•
The correctly aligned caustic will appear as a circle with Star in TEM mode. The image is shown
below.
•
Insert condenser aperture (First aperture) and
minimize the swinging beam using the condenser
X/Y adjustment screws when passing through
crossover.
3rd Cond Stig
3rd Cond stigmator
2nd Cond Stig
2nd Cond stigmator
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