Inficon Transpector XPR 3+, Руководство по эксплуатации

Страница: 62 / 130

4 - 2
Transpector XPR 3+ Operating Manual
Figure 4-1 Mass spectrum
Figure 4-1 is an example of a mass spectrum with an arbitrarily selected number
of 170 scans. The top graph shows the data taken during the 170 scans and the
selected mass peaks. The bottom graph is a trend analysis showing the most
important masses verses time. The prominent peaks for air are mass 28 from
Nitrogen, mass 32 from Oxygen, mass 40 from Argon, and mass 18 from water
vapor.
4.1.1.1 Ionization Process
When a sufficiently energetic electron strikes a gas molecule, there are many
processes that can occur, just some of which are summarized in
Table 4-1 .
Table 4-1 Electron impact ionization processes
XYZ + e
-

XYZ
+
+ 2e
-
(1)
XYZ
2+
+ 3e
-
(2)
XY + Z
+
+ 2e
-
(3)
XY
+
+ Z + 2e
-
(4)
X
+
+ YZ + 2e
-
(5)
X + YZ
+
+ 2e
-
(6)
XZ + Y
+
+ 2e
-
(7)
XZ
+
+ Y + 2e
-
(8)