Hitachi Microscope & Magnifier S-4800 Manual De Usuario

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3.1  Preliminary Operation 
 
3.1.1    Check of Column Vacuum 
   
At the beginning of SEM operation, check the evacuation control 
panel. The following conditions must be met: 
 
(1) Lamps of IP1IP2 and IP3 RESET switches are lit. 
 
 
 
(2) Ion pump readings are better than the followings. 
  IP1: 2 
×
 10
-7
 Pa   
  IP2: 2 
×
 10
-6
 Pa   
  IP3: 5 
×
 10
-5
 Pa   
(Pressing MODE switch on the Evacuation control panel shifts 
forward the blinking of status display lamps. Read vacuum when 
each of IP1 to IP3 lamp is blinking) 
If vacuum readings do not satisfy the above conditions, gun 
baking is required. Refer to 
Maintenance
 in section 4. 
 
(3)   EVAC POWER switch is set at 1 (ON). 
 
(4) TMP POW ONNORMAL lamps and the lamp of SC EVAC 
switch are lit. 
 
(5) Vacuum of S.C (specimen chamber) is better than 2x10-3 Pa. 
(Read vacuum when S.C lamp is blinking) 
 
(6)   APT HEAT switch is set at AUTO
Usually keep the APT HEAT switch on the evacuation control 
panel at AUTO
If the objective lens aperture is contaminated, charging will 
degrade image quality and the image will drift because of micro 
discharge. Such problems are noticeable at low accelerating 
voltages. The aperture is heated to about 150
º
C to remove contaminants to one tenth or less 
of what it would be at room temperature. 
 
The aperture heating will be turned OFF automatically when you press S.C AIR switch to 
introduce air into the specimen chamber. The 30 minutes wait will be placed automatically 
before introducing air when S.C AIR is started while APT HEAT switch is ON. The aperture 
heating will start again when the specimen chamber vacuum recovered by S.C EVAC 
operation. Note that after the aperture heating turned ON, image drift may be observed for 
about half an hour.