Zeiss GeminiSEM Series, Инструкция по эксплуатации

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3 Product and Functional Description | 3.3 Optional Components and Accessories ZEISS
1 Break push button
Stops the stage in an emergency.
2 T/Z joystick
Controls the Z axis and the stage tilt (T).
3 X/Y/R joystick
Controls the X- and Y-axes and the
stage rotation by turning.
Function
All axes are deflection-compensated. When the joystick is moved only slightly, the respective axis
moves slowly. Larger movements of the joystick result in a faster movement of the stage.
The X-, Y-, and Z-axes are magnification-compensated. When working at a low magnification, the
stage moves relatively fast. At higher magnifications the stage movement is slower. The stage is
moving with its maximum speed when viewing the specimen with the CCD (Charge Coupled De-
vice) camera.
The different axes can also be moved simultaneously.
3.3 Optional Components and Accessories
3.3.1 Optional Detectors
3.3.1.1 C2D Detector
Purpose The cascade current detector (C2D) is a special type of detector that you can use instead of the SE
detector to create a secondary electron image under variable pressure conditions.
The SE detector cannot be used under variable pressure conditions: The high potential at the scin-
tillator would cause an electrical breakdown with a lightning flash that runs from the scintillator
to the outer body.
Fig. 23: C2D image of a moth.
Function On the surface of the specimen, secondary electrons are created. The secondary electrons acceler-
ate towards the C2D detector due to the potential that is applied to the detector electrode.
On their way to the detector, the secondary electrons collide with residual gas molecules (nitro-
gen). The collisions ionize the residual gas molecules and create additional electrons, as well as
cations. The additional electrons also accelerate towards the detector and collide with further gas
molecules, which are ionized.
The result is a charge cascade that amplifies the original SE signal by a factor of up to 1000.
The electrons that result from the charge cascade are all collected by the electrode of the C2D de-
tector and the current is further amplified by the detector.
The cations that result from the charge cascade neutralize any negative charge on the specimen
that may have been created by the primary electron beam.
46 Instruction Manual ZEISS GeminiSEM series | en-US | Rev. 2 | 349500-8138-000