SRS Labs QMS 100 Series, Руководство пользователя

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2-12 Features and Operation
SRS QMS Gas Analyzer
example, if the background mode in Analog mode is changed to yellow, the background mode of
all the other modes remains unchanged. Also, any new file using the Analog mode still uses the
default background color.
After an RGA file has been edited to have a desired look, it may be used as a template for new
files by clearing its data using the Clear Graph Data command, saving it using the Save As
command, and opening it again using the Open command.
Head Management
The SRS RGA Head has nonvolatile memory that stores most head variables such as sensitivity
factors, Channel Electron Multiplier gain, high voltage, calibration factors, etc. When the RGA
program connects to a head, all these variables are read from the head and stored temporarily in
the program for use in the active file. When a head parameter is edited using the command in the
Head menu, that parameter is stored back in the head immediately.
Saving RGA files does not save any of the head parameters to that file since each RGA Head has
unique parameters due to minor variations in electronic and physical properties. Head parameters
cannot be changed unless an SRS RGA Head is connected and turned on.
Protecting Your RGA
A Maintenance Schedule menu item lets you protect your RGA by automatically turning the
filament or CEM off if the RGA is left to idle for a selected time.
Sensitivity Factors
The RGA Head uses two sensitivity factors stored in its non-volatile memory. The sensitivity
factors, one for total pressure and one for partial pressure, are used as conversion factors
between the ion currents received form the head and the pressure units selected by the user.
The sensitivity factors can be changed using the Sensitivity Tuning command in the Head menu.
In order to set these factors, you need a reference ion gauge installed in the same vacuum system.
The reading from the gauge is used to set the new sensitivity factor for the RGA Head.
Note : The pressure limits you may enter will change if you have the Pressure Reduction option
enabled. If this option is enabled RGA lets you enter much higher pressure values.
Spectrum Analysis
Mass spectrum analysis takes you one step beyond visual analysis and Library lookup tables.
RGA looks at the spectrum from 1 to 50 amu and uses a matrix inversion technique to analyze
the composition of the residual gas and approximate its composition. Note that Analysis mode
requires a minimum span of 1 to 50 amu. The span can be higher than 50 amu. Analysis data can
also be logged by clicking the Enable Analyze Logging box in the Analyze Settings selection in
the Utilities menu.