Design charts for trochoidal mass spectrometer as a vacuum analyzer are made for rational determination of the electrode dimension. The fundamental charts, Figs. 3, 4, 5 and 6, are calculated by Eqs. (4), (5), (6) and (7), where notations used are shown in Fig. 2. β is a coefficient defined as β=
Vo/
Ep, where
Vo,
E and
p represent the accelerating voltage of ion, the strength of electric field and the distance between d
o and d
n (refer to Fig. 2), respectively. The spreads
X and
Y of ion beam, in x and y directions can be obtained from these figures as functions of β and θ.
For example, considering the the conditions
Xmax =
Ymax and θ≤135°, the relations among (
X/a)
max (= (
Y/a)
max),
pβ/
a and (
s/a)
min are then given, in Fig. 8. From this figure, optimum value for
a (i. e.
b) corresponding to any value of
Xmax/
smin can be odtained. Table 1 shows a typical example of electrode design under the above condition.
Use of Figs. 3, 4, 5, and 6 also makes it easy to draw the path of ion beam.
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