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3. Voltage center of condenser lens
Note the direction of the caustic movement when going to
crossover.
•
Use the beam tilt controls (right sub panel) to shift the
caustic in the same direction of the movement and
brightness centering controls (right panel) to return the
caustic to the center of the phosphor screen.
•
Correct both 1st and 3rd order condenser astigmatism.
Repeat step 3 until caustic does not move with
directionality when passing through crossover. This
correction requires significant beam tilting if the previous
operator used the TEM alignment procedure.
•
Insert condenser aperture (3
central bright spot using by the condenser X/Y adjustment screws.
rd
th
or 4
) and centering by minimizing the tails of intensity surrounding the
18
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