FEI Quanta FEG 250, User'S Operation Manual, Page: 119 / 228

Stages: Stages Types and Accessories
7-5
Sample Top Surface Positioning
The distance between the observed sample and the stage rotation
head surfaces must be properly set to bring the stage to the eucentric
position. This procedure also prevents the specimen to touch the lens
pole when moving the stage in the Z-axis direction.
The Z coordinate can now be changed via the manual or software Z
control around the eucentric position and further, but not less than
1 mm from the lens for safety reasons.
TABLE 7-1 SAMPLE POSITIONING PROCEDURE
50 mm 100 / 150 mm
Load a sample onto the specimen holder.
Adjust the external Z
coordinate as high as
possible. Adjust the Z coordinate to bring the
specimen top surface
approximately 10 mm below the
lens.
Put the Eucentric Position
Adjuster on the stage base.
Bring the specimen top surface
point to the 2 mm adjuster
position by turning the
specimen holder internal screw.
Lock the position with the
locking cone.
Adjust the external Z
coordinate so that the
specimen top surface coincides
with the adjuster Eucentric
position.
Close the chamber and pump it down.
Switch on the beam, focus the specimen top surface and run the
Link Z to FWD function (see Chapter 4). The WD is now recognised
by the system as the
Stage module / Coordinates tab Z value.