Instruction Manual WGM701 Wasp
InstruTech
Page 17
Indicated pressure range from 7.60 x 10
-7
to 7.6 x 10
-2
Torr
(Gauge calibrated for air)
6
4
2
6
4
2
6
4
2
10
–4
8
6
4
2
10
–6
2
4 6
10
–5
10
–4
10
–5
8
6
4
2
10
–6
8
2
4 6 8
2
4 6
2
4 6
2
4 6
10
–3
8
10
–2
8
10
–1
8
10
–3
8
10
–2
8
10
–1
8
p
eff
(Torr)
p (Torr)
Indication range
10
-6
... 10
-1
Torr
Air
N
2
O
2
CO
Ar
He
Indication range below 1 x 10
-5
Torr
In the range below 10
-5
the pressure indication is linear. For gases other than air, the pressure can be
determined by means of the following conversion formula:
p
eff
= K × indicated pressure
where: Gas type
K
Air (N
2
, O
2
, CO) 1.0
Xe
0.4
Kr
0.5
Ar
0.8
H
2
2.4
Ne
4.1
He
5.9
These conversion factors are average values.
Example: If the gas in use is argon (Ar) and the CCM502 indicates a measured pressure of 7.6 x 10
-6
Torr,
p
eff =
0.8 X 7.60 X 10
-6
= 6 X 10
-6
Torr true pressure of
argon
gas
A mixture of gases and vapors is often involved. In this case, accurate determination is only possible with a
partial pressure measurement instrument, e.g. a quadrupole mass spectrometer.
