The Tune window tuning controls B-23
Source Temperature
(C)
The temperature of the source in °C. the normal
setting is between 180 and 200 °C which suits
most samples. For certain applications–for
example, high temperature GC–this can be
increased to a maximum of 350 °C.
Using a lower temperature can reduce fragmenta-
tion. However, this is likely to allow compounds
with a high boiling point to condense in the source,
which can reduce sensitivity over time.
Tip: A readback of 503 indicates that the source
heater is disconnected.
See also: EI/CI inner source maintenance on
page 10-18.
Electron Energy (eV) The voltage between the filament and the source.
Retain the default value of 70.
See also: Electron Impact ionization on page G-3.
Trap Current (µA) Measures the amount of electrons that hit the trap
and is used to control the current through the fila-
ment in EI mode. The parameter value of between
100 to 200. Increasing the value allows more elec-
trons to enter the source, increasing the ionization
of the sample and usually giving an increase in
signal intensity.
Note: This value is not used during CI or DCI
operation.
Filament Current (A) The current passing through the tungsten fila-
ment. This is normally between 4 and 5 A.
EI Tune tab parameters: (Continued)
Parameter Description
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