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MG14 operating manual Rev 1.4
4.2.7.1 Gas type correction menu – Gas Type
Sensors are normally calibrated for a measurement in nitrogen or in air. If pressure measurements
are being performed with other gases, is necessary to correct the reading accordingly. The
Gas Type parameter is used to adjust the correction factor for the respective gas type. The actual
pressure is obtained by multiplying the measured pressure with the correction factor:
where:
The gas type correction becomes a function of the pressure if the pressure exceeds 0.5 mbar. This
fact is taken into consideration for all gas types that can be selected.
The following gas type correction factors are implemented and can be choose using the narrow
buttons ▲or▼ and MENU/ENTER button for each channel separately:
Additional user can define any other gas type correction in the range 0 to 10, what makes MG more
flexible and customized.
IMPORTANT !
P = [I
/ (S
x I
)], where Sg = S
c
g
e
P – pressure
– Ion current
I
c
– sensitivity factor for gas g
S
g
– emission current
I
e
– gauge sensitivity for N
S
N2
Rg – gas correction factor
Gas
He
Ne
D
2
H
2
N
2
Air
O
2
CO
H
O
2
NO
NH
3
Ar
CO
2
CH
(methane)
4
Kr
SF
6
C
H
(ethane)
2
6
Xe
Hg
C
H
(Propane)
3
8
DEFINE
Tab.1-1 Gas correction factors
35
x R
N2
g
2
Rg
0,18
0,30
0,35
0,46
1,00
1,00
1,01
1,05
1,12
1,15
1,23
1,29
1,42
1,4
1,94
2,2
2,6
2,87
3,64
4,2
0...10
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