FEI Scios 2, Руководство пользователя

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Operating Procedures: Optimizing Imaging
C O N F I D E N T I A L – FEI Limited Rights Data 5-17
Ion Beam Current
The choice of correct ion beam current is determined by an application. A particular beam
limiting aperture is used to obtain a desired Ion beam current. The larger aperture applied, the
higher is a current. In general, use a smaller aperture for high resolution imaging and a larger
one for faster milling.
Use the following suggestions for choosing optimal ion beam currents:
Changing Ion Beam Current
There are 15 possible beam limiting apertures and so are 15 ion beam currents, selectable from
the toolbar list and from the
Column module / Beam current adjuster on the Beam Control page.
The current values and so the beam diameters depend on the accelerating voltage value (see
the following table).
Table 5-4
Ion beam diameters vs. HV and Ion beam current
Note

When changing the spot size, adjustment of the Detector module / Contrast and/or Brightness may be necessary to
optimize the imaging. An alternate approach is to use the Auto Contrast Brightness (F9) function.
Table 5-3
General Ion Beam currents
Beam Current [pA] Best Use
1.5 – 10 High resolution
30 – 50 Standard imaging
> 100 Milling