3 Product and Functional Description | 3.2 Electron Optical Column ZEISS
Fig.11: Mid-column aperture changer
Position Aperture diameter Typical application
0 750μm Optional VP mode (with 100μm VP aperture)
Optional EP mode (with 100μm EP aperture)
1 30μm HV mode
2 20μm HV mode
Optional EasyVP mode (with 400μm EasyVP
aperture in combination with a beamsleeve
aperture)
3 Apertures can be fit-
ted as an option
Stigmator
The stigmator coils
compensate for astigmatism so that the electron beam becomes rota-
tionally symmetrical.
Deflection System
The electron beam is focused by the objective lens
onto the specimen
while being de-
flected in a point-by-point scan (raster scan) over the specimen surface by the scanning coils
.
Signal Detection
When the primary electron beam hits the specimen, certain interaction products are released,
which can be recorded by specific detectors, e.g. the BSD detector
. For more information
refer to Principle of Signal Detection [
}
30].
28 Instruction Manual ZEISS EVO | en-US | Rev. 10 | 354706-0780-006