Grid Ion Source; Fig. 3: Electrode Arrangement And Potential Curve Of The Crossbeam Ion Source - Pfeiffer Vacuum QMA 4X0 Operating Instructions Manual

Degas
Degassing the crossbeam ion source is only recommended in exceptional cases.
● Pressure: ≤ 10
● Emission: ≤ 10 mA (at 550 V)
● Time: ≤ 5 minutes
100 V
0
-100 V
Fig. 3:
1 Wehnelt
2 Cathode
3 Ionization area
4 Extraction
Emission
V1
V2
V3
V4
V5
V6
Protection Current
Tbl. 4:
3.2.3 Grid ion source
The grid ion source has a very open design, has an extremely low outgassing rate and can be de-
gassed easily. It emits only a few surface ions. It is always equipped with two tungsten filaments.
4)
5)
-8 hPa
1 2 3 4 5
Electrode arrangement and potential curve of the crossbeam ion source
5
6
7
8
Typical values of the crossbeam ion source
With magnet 0.7 mA / At p > 5 × 10
Before reducing V2 to < 50 eV, reduce the "Emission" to 0.1 mA and V9 to < 20 V to prevent overloading of
the cathode.
6 7
Base plate
Focus
Entrance orifice
Rod system
Ion Reference
Cathode
Focus
Field Axis
Extraction
Inner Deflection
W
YO -Ir
x
-6 hPa, reduce to 0.1 mA.
Product description
8
1 mA
90 V
70 eV
20 V
15 V
250 V
300 V
4.2 A
3.5 A
4)
5)
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