Model 979 Series Helium Mass Spectrometer Leak Detector
DRAFT 9/15/03
C-9
Test pieces are generally
rough
pumped (or, if pressurized, the chamber in which they are to
be tested is
rough
pumped) by a mechanical vacuum pump before they are connected to
the spectrometer tube. This prevents overloading the vacuum pumping system.
Figure C-5
Magnetic Separation Principle
To
Preamplifier
Collector
Helium Ions pass
through slit and
are collected
Heavier
Ions
Lighter
Ions
Magnetic Field deflects
Helium Ions 90°, other ions
more or less than 90°
Summary of Contents for 979 Series
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