Hitachi Microscope & Magnifier S-4800 사용자 설명서

4-

1

 
 
 
 

4.1.1    Maintaining Vacuum of Electron Gun and Intermediate Chamber   
 
The electron gun shall be continuously evacuated. Keep ion pump power supply ON even when 

SEM is not operated. 
If ion pump vacuum degraded than the following value, perform gun baking.   
Refer to <4.10 Gun Baking operation> 

IP1:  2 

×

 10

-7

 Pa 

IP2:  2 

×

 10

-6

 Pa 

IP3:  5 

×

 10

-5

 Pa 

 

 
4.1.2    Replacement and Cleaning of Objective Lens Aperture 
 
Contamination of the objective lens aperture plate may cause increase of astigmatism or poor 
resolution especially at low accelerating voltage.   
To replace or clean up the aperture plate, use following steps. 
If you use low accelerating voltage and high magnification condition, coating with Pt-Pd or Au-Pd 
after cleaning the aperture plate may result better image. 
   
(1)   Turn off high voltage.   
 
(2) Press down the S.C. AIR switch on the evacuation control 

panel 3 second or longer. The lamp of the switch will begin 
blinking. If aperture heater was ON, 30 minutes wait time for 
cooling down begins. While the cooling period, the Numeric / 
Character display on the panel indicates APXX (XX is rest of 
wait time in minutes). After cooling time ha passed, TMP will 
be shut down and air introduction will begin. It will take about 10 minutes.       
 

NOTICE 

Wear gloves for the following steps. Do not touch to parts inside of vacuum area with your 
hand directly.   
 

(3) Place aluminum foil of about 20 

×

 20 cm on a table.     

All parts to be removed in the following steps should be placed on the foil.