70
Angular Ion Beam Current Density Profiles, Low Voltage Option
FIGURE B.9 and ”FIGURE B.10” on page 71 show exemplary ion beam
cu
rrent density profiles for the M
ark II source’s low voltage option, as
taken by a Faraday cup that was angularly swept at a fixed distance of
R=30cm from the ion source face. Source profiles for argon and oxygen
are shown for an anode current of 7.5A and at various anode potentials.
Ion beam current density readings at angles of ± 90° are nominally zero.
FIGURE B.8 Input Gas Flow
vs. Anode Potential (V
A
) and
Anode Current (I
A
) - Low
Voltage Option (Oxygen).
Operation Characteristics in Oxygen
(Low Voltage Option)
0
10
20
30
40
50
60
70
80
50 75 100 125 150 175 200 225
Anode Potential (V)
Source Input Gas Flow - Oxygen (sccm)
1 A
3 A
5 A
7.5 A
10 A
15 A
FIGURE B.9 Angular Beam
Current Density at R=30cm
and Anode Current= 7.5A -
Low Voltage Option (Argon).
Angular Ion Beam Current Density Profile at R=30 cm
(Argon with Anode Current of 7.5A)
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
-90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90
Angle (degrees)
Beam Current Density (mA/cm
2
)
50 V
75V
100V
150V
200V
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