Stanford Research Systems RGA100, Operating Manual And Programming Reference

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6-36 Ionizer Control Commands
SRS Residual Gas Analyzer
it has been set, FIL_ERR can only be cleared after succesfully turning on the
filament.
IEparam, param: 0,1, *, ?
Description : Ion Energy (eV).
Echo: STATUS error byte or query response.
Set the Ion Energy to one of two possible levels: Low (8eV) or High(12eV). The
parameter represents the ion energy level: 0 for Low and 1 for High.
Since the axis of the quadrupole mass filter is at ground, the ion energy (in eV) is
equal to the anode grid voltage (in Volts).
Important : The anode grid is always biased regardless of the ionizer’’s emission
status.
Upon reset the grid level is set to the default value.
Parameters :
IE0 Low ion energy: 8 eV .
IE1 High ion energy: 12 eV.
IE* : The default Ion Energy parameter value is used to run the command.
Default: 1 => high ion energy: 12 eV
IE?: Query. The value of the anode grid parameter is returned over RS232 in
ASCII format. Note that it is the parameter value and not the actual voltage level
that is returned.
Error checking:
Number parameters can be 0 or 1 only, and must be integers.
The absence of a parameter (i. e. IE ) is treated as a bad-parameter error.
VFparam, param: 0 - 150, *, ?
Description : Focus plate voltage (Volts)
Echo: STATUS Error Byte and query response.
Set the focus plate voltage in the ionizer. The parameter represents the magnitude
of the biasing voltage (negative) in units of volts.
The ions formed inside the anode grid are extracted into the quadrupole mass
filter by the negative attractive potential of the "Focus" or Extraction Plate. The
plate serves the double purpose of drawing the ions away from the anode grid,
and containing the ionizing electrons inside the source. Electron leakage into the
filter is only detectable at low mass settings (1 to 10 amu) and can easily be
eliminated biasing the focus plate at least 30V more negative than the repeller.