INFICON HAPSITE Smart Plus Chemical Identification System - Manual (Page 37)

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HAPSITE Smart Plus Operating Manual
The two vacuum pumps of the HAPSITE continue to provide the pumping
necessary for operation. These two pumps are the non-evaporate getter (NEG)
Pump and the smaller Sputter-ion Pump. The NEG Pump incorporates a special
zirconium alloy, arranged in sintered disks, which when heated adsorb gas
molecules very aggressively.
Over time, the sintered disks gradually become fully saturated with gas molecules
and the pumping speed drops. The instrument detects the resultant rise in
operating pressure (loss of vacuum) and the software signals that the pump must
be replaced.
The NEG Pump is very effective in removing the active gases, but the NEG Pump
does not remove noble gases. The sputter-ion pump is provided to remove argon,
neon, helium, krypton, and xenon which would otherwise accumulate in the mass
spectrometer. The accumulation would raise the mass spectrometer pressure and
interfere with operation.
The Turbo Molecular Pump in the Service Module is actually a compound pump,
incorporating turbo molecular stages for high pumping speeds at low pressure, and
molecular drag stages to provide good compression of the gas at higher pressures.
Even with the drag stages, this pump is unable to compress the gas enough to
exhaust the gas into atmospheric pressure. An additional Diaphragm Roughing
Pump is provided.
The Diaphragm Pump consists of four stages, in series. The Diaphragm Pump
draws the gas from the exhaust of the compound pump and compresses the
exhaust gas sufficiently to discharge the exhaust into the atmosphere.
1.6.4 Electronic Systems
The electronic systems in the HAPSITE are considered in four groups:
 Mass Spectrometer Control
 Gas Chromatograph Control
 Main Processor
 Interfaces
1.6.4.1 Mass Spectrometer Control
The Mass Spectrometer control electronics include the programmable DC and RF
power supplies for the Mass Selector, the DC power supplies for the filament, the
Electron Multiplier, the Sputter-ion Pump, and the A/D converter for the signal from
the Electron Multiplier.