Ulvac GI-M2, Instruction Manual

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81
Table. 13-1
Relative Sensitivity Factor of Ion Gauge for Each Gas with Respect to Nitrogen
and Relative Ionization Cross-Sectional Area
m/e N Molecule Srj Xj
Srj:
Relatibe sensitibity of
ionization gauge
Srj(N
2
)=1(actual
measurment value
Xj:
Relative ionization cross-
sectional area
Xj(N
2
)=1
Calculated value when ion
electron energy is75 eV
N:
No. of electrons per
molecule
Linear relationship holds
between Sr and Xj and,
when Srj of the gas is
unknown, it can be
predicted from Xj
Values marked with [*] are
cited from Reference 2.
Unfortunately, data on
other types of gas are not
available at ULVAC
4 2 He 0.221* 0.13
±
0.02
20 10 Ne 0.358* 0.25
±
0.05
40 18 Ar 1.34* 1.23
±
0.07
84 36 Kr 1.88* 1.84
±
0.06
132 54 Xe 2.50* 2.64
±
0.08
2 2 H
2
0.491* 0.38
±
0.04
4 2 D
2
0.40 0.41
15 10 NH
3
0.645* 1.23
18 10 H
2
O 1.25
±
0.44 1.03
28 14 CO 0.95* 1.06
±
0.03
28 14 N
2
1.00 1.00
30 15 NO 1.17
±
0.11 1.24
32 16 O
2
0.879 0.96
±
0.07
Air 0.97
±
0.1 0.75
34 18 H
2
S 2.20
±
0.02 2.03
±
0.20
36 18 HCl 1.65
±
0.21 1.61
±
0.02
44 22 CO
2
1.35* 1.39
±
0.08
44 22 N
2
O 1.66
±
0.27 1.30
±
0.17
146 70 Sfe 2.50 2.41
200 80 Hg 3.30
±
1.04 2.07
±
0.04
16 10 CH
4
1.58* 1.63
±
0.30
30 18 C
2
H
6
2.58* 2.74
±
0.45
44 26 C
3
H
8
3.44* 3.64
±
0.37
58 34 C
4
H
10
4.04* 4.57
±
0.47
72 42 C
5
H
12
5.60
±
0.76
86 50 C
6
H
14
6.60 6.77
±
1.44
100 58 C
7
H
16
7.60 7.72
114 62 C
8
H
18
8.18
128 70 C
9
H
20
8.86
26 14 C
2
H
2
0.614* 2.06
±
0.27
28 16 C
2
H
4
1.29* 2.27
±
0.28
42 24 C
3
H
6
1.77* 3.25
±
0.22
56 32 C
4
H
8
2.07* 3.82
±
0.59
70 40 C
5
H
10
4.81
±
0.99
84 48 C
6
H
12
6.37
±
0.86 6.49
112 64 C
8
H
16
7.22
126 72 C
9
H
18
8.72
140 80 C
10
H
20
10.37
78 42 C
6
H
6
5.18
±
0.42 5.19
±
0.50
42 24 Cyclo-C
3
H
6
3.75
70 40 Cyclo-C
5
H
10
6.01
84 48 Cyclo-C
6
H
12
6.40 6.60
±
1.59
92 50 C
6
H
5
-CH
3
6.81
40 22 CH
2
-C-CH
2
1.31* CH2=C=CH
2
40 22 CH
3
-C-CH 1.41* CH3-C
≡
CH
1) F.Nakao.Vacuum25(1975)201,431
2) K.NakayamaandH.Hojo;Jpn.J.Appl.Phys.Suppl.2Pt.1.(1974)113