Emission
1 mA
1)
V1
Ion Reference
90 V
V2
Cathode
70 eV
2)
V3
Focus
20 V
V4
Field Axis
10 V
3)
V6
Inner Deflection
300 V
V9
Wehnelt
30 V (max. 40)
Protection Current
W
YO
x
-Ir
4.2 A
3.5 A
Tbl. 3:
Typical values of the axial ion source
3.2.2 Crossbeam ion source
The open design of the crossbeam ion source allows quick reaction to changes in the gas composition.
It has a long service life and is equipped with two filaments. The crossbeam ion source allows the direct
passage of molecular beams perpendicular and parallel to the system axis.
Standard filament
W, with YO
x
-Ir also being available.
Gas-tight versions
In the case of gas-tight crossbeam ion sources, the ionization area is sealed. The conductance to the
vacuum chamber is approx. 1 l/s.
Selecting operating pressure for gas-tight versions
► Select an operating pressure of <10
-6
hPa in the vacuum chamber.
Application examples
● Analysis of particle beams and general gas analysis
● Qualitative and quantitative gas analyses (composition and chronological sequence)
● Analysis of reactive and aggressive gases (with special accessories)
● Detection of contamination in gases
● Isotope measurements
● Residual gas analysis on vacuum processors (e.g. plasma etching)
● Process monitoring / process control (e.g. closed-loop control of gas composition or of vaporiza-
tion sources)
● Molecular beam applications
Thanks to their minimal gas consumption, low de-mixing and low time constant, the gas-tight versions
are particularly suitable for:
● Measuring gases and solvents in fluids
● Respiration analysis
● Analysis of gas mixtures
● Trace detection thanks to less influence from the residual gas
● Corrosive or toxic gases
Function
The electrons emitted by the cathode and focused by the Wehnelt that is connected to the cathode en-
ter the ionization area through a gap and perpendicular to the system axis. In the ionization area, the
electrons ionize the gas. The ions are drawn out by the extraction electrode and focused into the mass
filter through the ion lens (focus). The electron beam, particle beam (if a molecular beam is admitted)
and ion extraction are perpendicular to each other. The field axis potential, which is a few volts below
the potential of the ionization area, mainly focuses ions from the ionization area into the mass filter.
1)
At p > 5 × 10
-6
hPa, reduce to 0.1 mA.
2)
Before reducing V2 to < 50 eV, reduce the "Emission" to 0.1 mA and V9 to < 20 V to prevent overloading of
the cathode.
3)
5 V at mass range 1024 or 2048
Product description
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