Zeiss Crossbeam 550, Инструкция по эксплуатации

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ZEISS 6 Operation | 6.3 Modifying Gun Parameters
6.3 Modifying Gun Parameters
6.3.1 Selecting the Gun Mode
Purpose The microscope can operate in different gun modes:
§
Normal
§ Imaging
§
Analytic
Normal Gun Mode
In Normal gun mode, the temperature of the Schottky emitter (gun / filament) and the extraction
voltage are optimized for a long lifetime of the Schottky emitter. Normal gun mode is suitable for
most applications.
Imaging Gun Mode
In Imaging gun mode, the temperature of the Schottky emitter and the extraction voltage are re-
duced in comparison to the Normal gun mode. This leads to a reduction of the energy spread of
the primary electrons. Overall, the probe current in Imaging gun mode is about half the probe cur-
rent in Normal gun mode.
Imaging gun mode is especially useful at low kV or at high magnifications to reduce chromatic
aberration and to achieve a better resolution. Switching from Normal gun mode to Imaging gun
mode is useful for reducing the probe current without any need for beam adjustments.
Analytic Gun mode
In Analytic gun mode, the Schottky emitter runs at default temperature but the extraction voltage
is increased in comparison to the Normal gun mode. This leads to a higher probe current. Overall,
the probe current in Analytic gun mode is about twice the probe current in Normal gun mode.
The Analytic gun mode is especially useful for applications which require high intensities (e.g.
WDX).
Info
After switching the gun mode, you can immediately work with the selected gun mode. For ap-
plications, which require a high probe current stability, wait 24 hours until a stability of 0.2 %/
h is reached. It is recommended not to change the gun mode during quantitative specimen
analysis.
1. From the Menu Bar, select Tools > User Preferences.
à
The User Preferences dialog is displayed.
2. Select User > Expert Gun Mode.
3. Click in the Value field and select Yes.
4. Close the User Preferences dialog.
5. In the Panel Configuration Bar, double-click Crossbeam SEM Control.
6. In the Crossbeam SEM Control panel, select the Control tab.
7. In the Beam section, click one of the following buttons:
To switch to Imaging gun mode, click Imaging.
To switch to Normal gun mode, click Normal.
To switch to Analytic gun mode, click Analytic.
INFO: For maximum probe current, also check the alignment of the gun.
INFO: If you use the Analytic gun mode, then the lifetime of the emitter is reduced.
Instruction Manual ZEISS Crossbeam 550L, Crossbeam 550 | en-US | Rev. 3 | 349500-8122-000 79