FEI Quanta FEG 250, Руководство пользователя

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System Options: Automatic Aperture System
9-3
Automatic Aperture System
The Automatic aperture system (AAS) option enables a motorized
final lens strip aperture exchange.
Aperture
The Beam menu / Aperture selection list (see Chapter 2 and 5)
enables to choose the Final Lens Aperture.
Home Apertures
This feature moves the Final Lens Aperture aperture mechanism to its
home position. This is recommended when system cannot operate
the apertures properly.
Note:
An aperture diameter can also be displayed in the databar.
Moreover the beam current could be chosen instead of the Spot size
(see the
Preferences… / General tab) to be displayed in the toolbar
list box and in the Column module / Beam Current preset /
continuous adjuster:
• The Spot size / Beam current control (Spot size / Beam current)
select a desired value to be used with the system.
6 - APERTURE ALIGNMENT
This supervisor procedure provides a high precision aperture setting.
When you find an illumination and adjust the aperture position near
the 2D box border, click the Save button. This stores the X / Y position
and the alignment cross is centred (since it shows a relative position
against the last saved coordinates). Then repeat the procedure when
necessary.
It is also possible to adjust the aperture strip position with the use of
mechanical knobs instead of the 2D box (see Chapter 2). In this case
the values are displayed (Step 2 of 3).
Note:
When adjusting the 1000 µm aperture (available on every strip for the
service reasons), just try to find the maximal illumination, do not use
the Modulator.