Stanford Research Systems RGA100, Operating Manual And Programming Reference

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5-8 Features and Operation
SRS Residual Gas Analyzer
time to acquire each partial pressure depends on the scan speed selected (the plotting
speed depends on the user's computer).
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 Mass Spec Scan Parameters dialog box
activated by the Scan Parameters… command or the shortcut button of the Parameter
button . 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 either the Schedule command from the Scan menu or the shortcut button of the clock
figure
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).
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) or the shortcut button of the Parameter
.
Table entries can be configured independently from each other. Some entries can use
the Channel Electron Multiplier (CEM), while others can have different scan speeds with
the CEM off.
The alarm control and level settings can be edited by either double- clicking on the
Alarm text of the desired table entry, or by clicking on the 'Alarm X' (where X is the
channel number) button for the appropriate table entry in the Table Parameters dialog
box.
Select the Schedule command (Scan menu) or the shortcut button of the clock figure
to
set the scan trigger timing and frequency. The Table Traces may be edited by either
double-clicking on the text directly (except for the Alarm text), or by selecting the Traces
command (Graph menu).
Important: Table mode, P vs T mode, and Annunciator mode share the same table scan
parameters, alarm parameters, and graph trace colors.