SRS Labs QMS 100 Series, User Manual

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2-2 Introduction
SRS QMS Gas Analyzer
Introduction
The SRS RGA is a mass spectrometer consisting of a quadrupole probe, and an Electronics Control
Unit (ECU) which mounts directly on the probe’s flange and contains all the necessary electronics for
operating the instrument.
Figure 1 Quadrupole Head Components
The probe is a specially engineered form of quadrupole mass spectrometer sensor. It is mostly
constructed out of type 304 stainless steel and high purity alumina. It analyzes residual gases ionizing
some of the gas molecules (positive ions), separating the resulting ions according to their respective
masses and measuring the ion currents at each mass.
The total probe equipment consists of three parts: the ionizer, the quadrupole filter and the ion detector.
All of these parts reside in the vacuum space where the gas analysis measurements are made.
Figure 2 Probe Components
A stainless steel tube (RGA cover nipple) covers the probe assembly with the exception of the ionizer.
A high vacuum environment (10
-4
Torr or less) is required for operation.