Zeiss EVO, Instruction Manual

Page: 120 / 180

7 Troubleshooting | 7.2 Column ZEISS
7.2 Column
7.2.1 Baking out the Gun Head
The gun vacuum deteriorates with time. For an optimum use of the LaB₆ filament it is essential
that the gun vacuum is always in the 10⁻⁷ mbar region. If the pressure rises above this value, it is
strongly recommended to bake out the gun head.
This procedure consists of the following steps:
1. Switching off the Gun | LaB₆ Filament [
}
120] or Switching off the Gun and EHT | Tungsten Fil-
ament [
}
120]
2. Starting the Bakeout [
}
121]
3. Switching on the Gun | LaB₆ Filament [
}
68] or Switching on the Gun and EHT | Tungsten Fila-
ment [
}
72]
7.2.1.1 Switching off the Gun | LaB₆ Filament
Info
If you operate the microscope with a LaB₆ filament, then you need to switch on or switch off
the gun and the EHT separately.
Procedure
1. In the right part of the Status Bar , click .
à The pop-up menu for vacuum, gun, and EHT activation is displayed.
2. Click Shutdown Gun .
3. Wait until the gun has ramped down.
à
This may take up to 5 minutes.
7.2.1.2 Switching off the Gun and EHT | Tungsten Filament
Info
If you operate the microscope with a tungsten filament, then the EHT and the gun are always
switched on or switched off together. You cannot separately switch on or off the EHT or the
gun.
Info
Tungsten filaments have only a limited lifetime of 100–300 operating hours. If you operate the
microscope with a tungsten filament, then do the following:
4
If the microscope is not in operation, then always switch off the EHT and gun to preserve
the filament.
4
Enable Auto Saturation at shutdown .
Procedure
1. In the right part of the Status Bar , click .
à The pop-up menu for vacuum, gun, and EHT activation is displayed.
2. Click Shutdown Gun .
3. Wait until the gun has ramped down.
à
This may take up to 5 minutes.
120 Instruction Manual ZEISS EVO | en-US | Rev. 10 | 354706-0780-006