Zeiss GeminiSEM Series, Инструкция по эксплуатации

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3 Product and Functional Description | 3.2 Main Components ZEISS
17 Pre-vacuum separation valve (PVS) 18 Buffer tank for optional Quiet Mode
Function In any of the variable pressure modes (Standard VP, NanoVP, and XVP), the pre-vacuum pump
16
directly evacuates the specimen chamber
6
. The roughing backing valve (RBV)
15
opens the connection between pre-vacuum pump and specimen chamber. The TIV
8
is closed
so that the turbo pump
9
is separated from the specimen chamber. The turbo pump evacu-
ates the lower part of the column via a bypass
5
. The gas flow valve (GFV)
11
supplies VP-
gas to the specimen chamber. The required variable pressure (VP) can be set via the VP Control
window of the SmartSEM user interface. The pressure can be set between 5 and 500 Pa, depend-
ing on the variable pressure mode.
The vacuum in the specimen chamber is measured by the Pirani gauge
14
. The detected pres-
sure values are displayed as Chamber = x Pa in the SmartSEM user interface. As long as the de-
tected pressure in the specimen chamber is not ready for operation, the column chamber valve
4
is closed in order to separate the specimen chamber from the column.
For working in any of the variable pressure modes, refer to Working with Variable Pressure
[
}
103] .
Standard VP Mode When changing to Standard VP mode, the acceleration voltage decreases to zero (if ON) , the col-
umn chamber valve closes, the TIV closes, the RBV and the GFV open. As soon as the chamber
pressure has reached the user value, acceleration voltage switched on again and the column
chamber valve opens.
The booster voltage is turned off in this mode.
Electron detection is provided via a dedicated VPSE or C2D detector, or via a backscatter detector
(AsB/aBSD/aBSD-LH).
Nano VP Mode When changing to Nano VP mode, after the acceleration voltage decreases to zero (if ON) and
the column chamber valve closes, the stage is lowered by 20 mm to give space for the beam-
sleeve aperture. The beamsleeve is automatically inserted. After the TIV closes, and RBV and GFV
open, the system is doing a leak test if the beamsleeve aperture is vacuum tight fitted to the ob-
jective lens. If the leak test is not successful the system will go back to High Vacuum mode and a
screen message is displayed. If the leak test is successful, the chamber pressure is set to the user
value, column chamber valve opens and acceleration voltage is turned on. The maximum chamber
pressure depends on the size of the beamsleeve aperture.
The booster voltage is turned on in this mode.
Electron detection is provided via a dedicated VPSE or C2D detector or via a VP-BSD1 detector
mounted on the beamsleeve. As the booster voltage is on, also InLens SE and EsB detectors can
be used.
For working in Nano VP mode, refer to Using Nano VP or XVP Mode [
}
105] .
XVP Mode When changing to XVP mode, after the acceleration voltage decreases to zero (if ON) and the col-
umn chamber valve closes, the stage is lowered by 20 mm to give space for the beamsleeve aper-
ture. The beamsleeve is automatically inserted. After the TIV closes, and RBV and GFV open, the
system is doing a leak test if the beamsleeve aperture is vacuum tight fitted to the objective lens.
If the leak test is not successful the system will go back to High Vacuum mode and a screen mes-
sage is displayed. If the leak test is successful, the chamber pressure is set to the user value, col-
umn chamber valve opens and acceleration voltage is turned on. The maximum chamber pressure
depends on the size of the beamsleeve aperture.
The booster voltage is turned off in this mode.
Electron detection is provided via a dedicated VPSE or C2D detector or via a VP-BSD1 detector
mounted on the beamsleeve. As the booster voltage is off, beamsleeve bias is deactivated and al-
ways zero.
For working in XVP mode, refer to Using Nano VP or XVP Mode [
}
105] .
32 Instruction Manual ZEISS GeminiSEM series | en-US | Rev. 2 | 349500-8138-000