Stanford Research Systems RGA100, Operating Manual And Programming Reference

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5-20 General Utilities
SRS Residual Gas Analyzer
Analyzing the Mass Spectrum
Spectrum Analysis description
This utility provides the user with immediate analysis of residual gas based on a
complete histogram or analog scan. Using a matrix inversion technique, the
composition of the residual gas is analyzed and the best approximation to its composition
is given in either pressure units or percentages. The user can enable up to 12 common
gases for analysis. This function
is only available during active scanning.
Note:
Analysis mode is only available in Analog mode or Histogram mode. The mass range
must be at least from 1 to 50 amu.
Analysis Procedure
Make sure the RGA window is in either Analog mode or Histogram mode and connected
to an RGA head. Set the scan range to be from 1 amu to at least 50 amu.
1. Select the Analyze Setups command from the Utilities menu to access the gas
selection display box, and select/unselect gases from the library for analysis.
2. Select the Analyze command from the Utilities menu or click the analysis button
in the Tool Bar to activate the analysis function.
3. To bring up the Spectrum Analysis dialog box, select the Analyze Window command
from the Utilities. You may place the dialog box anywhere on the screen.
4. Press the Setup button if you need to change the gas selection or the analysis units.
5. Select the Start command form the Scan menu (if not already scanning) to begin a
scan.
6. When the scan is complete (the stop mass is reached) the analysis results will be
displayed in the Spectrum Analysis dialog box. The analysis will be repeated every
time the scan reaches the stop mass.
Note:
You may enable or disable the analysis procedure even while the RGA Head is
performing a scan by clicking the analysis button.
Averaging scan spectrum
One of the methods to improve noisy signals is signal averaging. The RGA program
has the function of the averaging signals over a user defined value (the default value is
12). The user can setup this function at any time.
1. Select Average Setup… command in the Utilities menu. Average Setup dialog box
will be pop upped.
2. Choose the desired method and set the average number and a condition.
3. Click ‘OK’ to close the pop up window