SRS Labs QMS 100 Series, User Manual

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Features and Operation 2-7
SRS QMS Gas Analyzer
Analog (Mode Menu)
Analog mode is the spectrum analysis mode common to all Residual Gas Analyzers. The X-
Axis represents the mass range chosen in the Mass Spec Parameters menu. The Y-Axis
represents the ion current amplitudes of every mass increment measured.
Select the Schedule menu to set the scan trigger timing. Once the scan is in progress, the
AutoScale menu may be used to scale the data.
The Analog Trace parameters such as color and width may be changed by either double clicking
on a data point directly (if data is present) or by using the Traces command from the Graph
menu.
In Analog mode the RGA Head scans from the start to the stop mass using the Points Per AMU
variable specified in the Scan Parameters dialog box (Scan drop-down menu or click the Mass
Spec Scan Parameters menu button on the toolbar). This Points Per AMU variable is used to
determine the mass increments between data points. The time to acquire each partial pressure
depends on the scan speed selected (the plotting speed depends on the user's computer).
The control view bar may be used to zoom, scroll and view all data, even if a scan in progress.
Histogram (Mode Menu)
Histogram mode displays the individual mass amplitudes for the selected scan range. In this
mode the RGA head performs a peak-lock for each mass and calculates one amplitude per mass.
This peak is then plotted as a bar at the appropriate mass. The X-Axis represents the mass range
chosen in the Scan Parameters menu. The Y-Axis represents the ion current amplitudes of every
mass measured. A mass index indicator is located at the left of the X-Axis. The index displays
the mass that is currently being updated (assuming a live scan is in progress).
Use the Schedule command from the Scan menu to set the scan trigger timing. Once the scan is
in progress, the AutoScale command (Graph menu) menu may be used to scale the data.
The Histogram Traces (bars) colors may be changed by either double clicking on the bars or
selecting the Traces command from the Graph menu.
In Histogram mode the RGA Head scans from the start to the stop mass running 7 measurements
per AMU. After performing a peak lock on each 7 points it then sends the maximum value to the
RGA program. This results in one point per mass being plotted as a bar graph. The time to
acquire each partial pressure depends on the scan speed selected (the plotting speed depends on
the user's computer).
The control view bar may be used to zoom, scroll and view all data, even if a scan in progress.
Table (Mode Menu)
Table mode presents a tabular form readout of preselected gases along with alarm level
warnings. The gas masses, names, and parameters can be set using the Scan Parameters
command (Scan menu). The scan parameter dialog also can be evoked by clicking on the Mass