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Fig. 1.1: Schematics of the vacuum system with 200-mm airlock
The 200-mm airlock allows you to introduce a specimen (
3
) while the vacuum of the specimen
chamber is maintained. As soon as the airlock chamber is evacuated, the gate valve can be
opened. The specimen is transferred into the specimen chamber by using the airlock rod.
Since the volume to be evacuated during specimen exchange is significantly smaller than that of
the whole specimen chamber, the pumping time will be reduced noticeably. Moreover, the risk of
contaminating the specimen chamber is minimised.
The vacuum in the airlock is measured by a Pirani gauge.
1
Airlock chamber
5
Specimen stage
2
Airlock door
6
Specimen chamber
3
Specimen
7
Column chamber valve
4
Gate valve
8
Gun head area
1
5
2
3
4
7
6
8
