SRS Labs QMS 100 Series, Руководство пользователя

Страница: 51 / 280

Head Calibration and Security 2-21
SRS QMS Gas Analyzer
Please refer to the RGA Tuning Chapter for more information about tuning and
calibration.
While performing the tuning procedure the total pressure in the vacuum chamber should
be around 10E-6 Torr.
In order to set the sensitivity factors of the RGA Head you must have a reference pressure gauge
installed on your vacuum system. There are two sensitivity factors, one for total pressure and one
for partial pressure. Both factors are stored in non-volatile memory in the RGA Head.
To tune the sensitivity factors do the following:
Make sure you are connected to the head.
1. Select the Sensitivity Tuning command from the Head menu.
2. Select which sensitivity factor you would like to adjust from the Measurement
Mode section (Partial or Total).
3. If you selected Partial Pressure then enter the mass whose pressure you will
be measuring in the Mass Selection edit box.
4. Enter the pressure indicated by your pressure gauge in the Reference Pressure
Reading.
5. Press the Measure button.
6. Press Accept to start using the new factor(s) or Undo to revert back to the old
one(s).
Adjusting the CEM Gain
The CEM gain may be set to any desired value between 10 and 1,000,000. The RGA program
will automatically search the required high voltage for such a gain if the Adjust button is
pressed.
All data acquired while the CEM is ON gets divided by the gain automatically before it is
displayed.
To change the CEM Gain do the following:
1. Connect to an RGA Head with a CEM option (Utilities menu).
2. Select the Channel Electron Multiplier command form the Head menu.
3. Select the Pressure Measurement Mode and the Partial Pressure Mass (if
partial pressure is selected).
4. Enter the desired gain in the Gain edit box.
5. Press the Adjust button and wait for the procedure to finish.
6. Press OK.