Column Alignment; Centering The Beam; Alignment Of Thermionic Gun - Philips CM12 Setup Manual

Erwin Sabio

Column Alignment

Centering the Beam

Alignment of the Thermionic Gun
Figure 9 The shadow of the filament
becomes visible at low saturation.
Figure 10 The STIG, DF, and ALGN
buttons activate the multi-function
knobs.
Philips CM12 Alignment & Setup Manual
1. To center the beam more easily, adjust the intensity
knob [9] to find the cross over i.e. the brightest and
more focused beam setting. (Note: if the intensity knob
is a little hard to control, press the FINE button [10] to
spread or concentrate the beam more slowly.)
2. Check to see if the center of the beam coincides with
the black dot on the screen.
3. Use the X & Y shift knobs [15] to center the beam.
1. Adjusting the tilt of the gun ensures that the beam of
electrons is directed to the center of the sample area.
Start by centering the cross-over beam as described
earlier.
2. Undersaturate the gun by going to MODE >
CONFIGURATION and turning the Filament Knob [18]
counter-colckwise until the shadow of the filament
becomes visible in the beam as in Figure 9.
3. Press the ALGN button to the right of the multifunction
knobs [21] then select GUN > TILT from the menu that
appears onscreen. At this point the multifunction X/Y
knobs become active and now be used to adjust the tilt
of the gun.
4. Adjust the multifunction X/Y knobs until the shadow of
the gun in the beam becomes centered and as
symmetric as possible.
5. Once the gun has been tilted correctly, press the ALGN
button again to exit the gun alignment mode.
Page 9