3 Product and Functional Description | 3.2 Main Components
ZEISS
Gun Vacuum
In the gun head, an ultra high vacuum is maintained by ion getter pumps
6
. The vacuum in
the gun head is displayed as Gun vacuum in the SmartSEM software. It should be below
1 × 10⁻⁸ mbar.
Venting
The specimen is located in the evacuated specimen chamber. To open the specimen chamber for
specimen exchange, you have to break the vacuum in a controlled manner. This is done by the
Vent command via the SmartSEM user interface or by pressing the
Exchange
push button on the
optional control panel.
When the Vent command is received, the column chamber valve closes and gaseous nitrogen
flows into the specimen chamber via the vent valve
9
. As soon as the pressure equilibrium is
obtained, the chamber door can be opened to change the specimen.
Evacuating
In order to continue operation, the Pump command makes the pre-vacuum pump and the turbo
pump evacuate the specimen chamber.
As soon as the vacuum in the specimen chamber is ready for operation, the column chamber
valve opens and the EHT Vac ready message is displayed in the SmartSEM user interface. Gun and
EHT can be switched on.
Quiet Mode
The automatically controlled
Quiet Mode
is optionally available. This option allows switching off
the pre-vacuum pump after specimen exchange when the vacuum threshold is achieved.
30
Instruction Manual ZEISS Crossbeam 550L, Crossbeam 550 | en-US | Rev. 3 | 349500-8122-000
Summary of Contents for Crossbeam 550
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