Description of the Microscope
11
VEGA 3 SEM
4.1.1
Electron Column Displaying Modes
RESOLUTION Mode
This is the basic and most common displaying mode. The IML lens is switched off, the OBJ
lens is excited and it focuses the final electron beam.
Characteristics:
high resolution
low depth of focus
In this mode, the VEGA 3 works like other common three lens
microscopes without IML lens. The aperture is nearly optimal for
lower BI values (small spot size, low beam current), short
working distances (4 - 5 mm) and for the accelerating voltage
30 kV. The pivot point of the scanning and the electric image
shifts are close to the principal plane of the objective OBJ,
so that the curvature of the field, distortion and field of view are
as good as possible. The centering of the objective OBJ is
performed by defined beam tilt of the central electron beam,
which does not cause image shift. This mode is intended for
displaying with the highest resolution.