Agilent Technologies VacIon Plus 800 Manual Del Usuario página 227

Technical Information
Symptom
8) – System fails to
achieve desired UHV
vacuum pressure.
9) – System fails to
achieve desired UHV
vacuum pressure
10) – Sudden and
unexplained pressure
(current) increases take
place with regular
frequency.
Agilent VacIon Plus 800 User Manual
Possible cause
System not appropriately
cleaned for UHV. Excessive
outgassing from walls limits
base pressure.
The pressure indication is not
given by a gauge, but it comes
from the conversion of the ion
pump current, that may be
affected by leakage.
Instability for noble gases
occurs. It is worth noticing that a
small quantity of noble gas
(argon) is present in the air
composition.
Correction procedure
Clean all components for UHV and bake
the system again.
Verify that leakage current occurs (see the
dedicated paragraph) and then high-pot
the pump.
Bake the ion pump and the system with
the ion pump off and a turbomolecular
pump as support. This should partly
remove the noble gases inside the ion
pump. Choose the most appropriate
pumping element for noble gases
(StarCell is recommended).
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