Zeiss EVO - Electron Optical Column

ZEISS 3 Product and Functional Description | 3.2 Electron Optical Column
3.2 Electron Optical Column
Purpose
The EVO column is the area of the microscope, where electrons are emitted, accelerated, de-
flected, focused, and scanned.
1
2
3
4
5
6
7
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Fig.10: Schematics of the electron optics
1 W or LaB₆ filament 2 Gun alignment and emission display
coils
3 Double condenser system 4 Mid-column aperture changer
5 Scanning and stigmator coils 6 Objective lens with through-the-lens
pumping
7 Backscattered Electron Detector (BSD)
or optional High Definition Backscat-
tered Electron Detector (HDBSD)
8 Specimen
Gun
A filament serves as gun
1
.The filament is heated by applying the filament current. The heated
filament emits electrons.
EHT
The acceleration voltage (U
EHT
) accelerates the emitted electrons.
Gun Alignment
and Display Coils
The gun alignment and emission coils
2
center the electron beam.
Condenser
A double condenser system
3
allows the continuous regulation of the probe current.
Apertures
The electron beam passes through the currently selected aperture in the mechanical mid-column
aperture changer
4
to ensure that the optimum quality of beam is maintained.
The design of the aperture changer allows for using 4 apertures. Three apertures are fitted as
standard (positions 0–2). The position of each aperture is marked on the mid-column aperture
changer.
Instruction Manual ZEISS EVO | en-US | Rev. 10 | 354706-0780-006 27