Table of Contents
Advertisement
ALZEFts
In
ion counting operation there
is
an
additional criterion
6.L4
Integral spectrum
for
the minimum peak width:
Either
a
standard spectrum
or an
integrei spectrum
(can
d)
Ammin
2
¼
amu
at
½
Ima×
be used for
total
pressure
measurement
[11)
can be ta-
ken, depending
on
the
mass
separation (resolution)
set-
ting:
PEAK·F
(FIR
filter
criterion)
The
peak process algorithm
is
used on
a
measured value
<mass>
«RESOL»
:
«1» to
«255» --> Standard spectr.
processed
in
the
FIR
(Finite Impulse
Response)
filter
<mass>
«RESOL»
;
«OFF» --> Integral
mass
spectrum
(such as
in the SCAN-F function,
refer
to section
6.1.1).
LuJ
The
FlR
filter
can be
used
to
particular advantage
here
<mass>
«RESOL»
:
«ON»
-->
Standard spectrum
because
the measured values
are freed of
most noise
and
other interference signals, allowing
a
very low
level
<mass>
«RESOL»
:
«OFF»
--> Integral
mass
spectrum
criterion to
be
set.
It
also
suppresses
peaks
that
are
too
widek
to
narrow.
a)
The 'peak
width'
must
be wider
than minimum width
6.2
Adjust
mPeak
>
nlmin
-
"ht_
When
used in
«SAMPLE» mode, the
Adjust function
ab
lows the selected measurement channel to optimi2e
peaks automatically
when
«ENABLE»
is
set
in
<aux>
b)
The 'peak
width'
must
be narrower
than maximum
«STATE».
width
Ammax
This possibility
is
advantageously
used, for
example, to
optimize the system
in
general
at
regular intervals and
particulady after several parameters
have been
changed.
6.2.1
Coarse search
Am
<
Am
o
me
A
search
is
made
for
a
peak around mass number
M
Peak
max
----
--
.
.
within
a
specified
search area,
c)
The
'peak heíght' must
be
higher than the selected
Peak criteria
leveL
Three criteria must
be
met
for
a
peak to
be
recognized
as
IPeak
max
×
mantíssa value
in
«CALIB»
a
peak:
a)
The maximum
intensity
(peak)
must
be at
least
twice
as
high
as
the minimum
of
the previous
valley,
In1ansity
t
4
i
Level
lam<
Peak
Level
-----------
•
Imax
>
2 x
Insin
Maso famui
QMS424o.opm
Measuring
ith
the
OMS
421
65
Advertisement
Table of Contents
