48
BG 805 981 BE (0201) QMG422.oi
The mass number should be selected in such a way that no ion current occurs.
With
CLEAR
you can disable the offset correction; the offset values are set to zero.
The values of the ranges 10
-5
, 10
-7
, 10
-9
, 10
-11
A are not displayed, they are
available at the interfaces.
400
For offset measurement the SEM voltage is switched off automatically,
RESOL
= 1,
F.A.
= 0 V and
EMISS
= 10
µ
A are set. If you switch
filam
off,
measurement takes place without emission.
125
For offset measurement the SEM voltage and the emission are switched off
automatically.
With the IC 421 and CP 400 ion counter the measured value is displayed as a
quasi-logarithmic bar across ten decades. The range is always selected automati-
cally; for linear analog output the display range is selected with O
-RNG
.
The discriminator threshold of the CP 400 preamplifier is set with
amplif-CP-LEV
.
Recommended value: 0.1...0.3 V with
SEM-VOLTAGE : 2500 V
.
The ion polarity is selected by choosing the ion source type
ion src-TYPE:SPEC+
for positive ions or
SPEC–
for negative ions.
With
detect-TYPE:EXTERN
you can capture analog measured values of a different
unit in place of the EP 422. Connect the signal to the EXT IN pins of the
ctrl
connector on the QC 422 (see p.11)
amplif-GAIN
determines the gain (×±1/×±10).
For experiments and tests a simulated spectrum according to the following diagram
is available with
config-SIMUL:INTERN
. Use it to familiarize yourself with the
operating procedures. For this purpose you do not need a vacuum system and also
no equipment such as QMH or QMA.
The spectrum is generated as an HF generator control signal
scan
and inserted
into the QC 422 electrometer signal path. It can be used in all
mass modes
.
For normal measures the simulation must be switched off:
config-
SIMUL:OFF
.
Only the detector types
FARAD
and
SEM
are admissible.
config-SIMUL:EXTERN
is reserved for factory tests.
20%
40%
60%
80%
100%
Cycle
restarts
32
28
34
40
44
65
66
14
16
18
20
2
1
F.S.
The peak intensities for
RANGE
10
-5
, 10
-7
, 10
-9
and 10
-11
are identical. The intensity
is amplified by a factor of 10 for the intermediate ranges. The spectrum is repeated
periodically from mass 64.
6.5 Ion counter
6.6 Extern input
6.7 Simulation