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3 Product and Functional Description | 3.2 Main Components
ZEISS
Fig. 29: Comparison of surface information at different acceleration voltages: Acceleration voltage = 1 kV: Good, sur-
face-sensitive imaging (left); Acceleration voltage = 10 kV: Thin layers are not seen (right)
Fig. 30: Comparison of surface information at different acceleration voltages: Acceleration voltage = 5 kV: Good, sur-
face-sensitive imaging (left); Acceleration voltage = 15 kV: Transparent surface caused by increased penetration
depth (right)
The working distance has a significant effect on the efficiency of the SE detector. Shadowing ef-
fects occur when the working distance is too short. If the specimen is too close to the objective
lens, most of the electrons will be deflected by the field of the electrostatic lens or move to the
objective lens itself. This means they cannot be detected by the SE detector.
Depending on the specimen material and on the specimen geometry, a minimum working dis-
tance of approximately 4 mm should be used. Extreme signal loss is likely to occur if shorter work-
ing distances than this are used. Conversely, the SE detector is very good when used for imaging
at long working distances. This is particularly important for low magnification imaging that is nec-
essary for adjusting the orientation of the specimen holder or locating a specific area on the speci-
men.
Optimal Initial
Settings
The following settings provide a good field of view for navigating on the specimen at low magni-
fications:
§
Initial working distance in the range of 10 mm to 20 mm.
§
Acceleration voltage of approximately 10 kV.
The imaging conditions can be readjusted for a desired application after identifying the area of in-
terest on the specimen.
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Instruction Manual ZEISS SIGMA series | en-US | Rev. 7 | 352102-9344-006