Hitachi Microscope & Magnifier S-3400N User Manual

4.1    Maintenance of Electron Optical Column 

4 - 6 

NOTICE:  Adequate care should be taken to prevent any dust particles from intruding into the 

electron gun unit or the inside the column. 

 
(12)  Either press the EVAC switch on the Evacuation Control Panel or the EVAC control button 

located on the right side of the Observation Screen Control Panel. Wait until the 
evacuation process finishes. 

 

 

 

 

 
 

EVAC Panel 

Control Panel 

 

Fig. 4.1-13    Evacuation Control Panel 

 
(13)  When application of accelerating voltage is enabled, apply an accelerating voltage, and 

 
 
4.1.2  Maintenance for the Objective Lens Movable Aperture 
 
A dirty objective lens movable aperture can cause a stigma aberration with a significant impact 
on image resolution. Although how often the objective lens movable aperture should be serviced 
depends on the frequency of use of it, it should be serviced as follows: 
 

①  Periodically once every six months under normal usage conditions 
②  If resolution declines apparently due to a dirty aperture 
③  More frequent routine maintenance may be required if a low accelerating voltage (less 

than 5 kV) is ordinarily used. 

 
Maintenance procedures are given below. Operating instructions based on 3D CG are also 
available. For further details, see <2.3.4 Menus>.