ECRIS - Electron Cyclotron Resonance Ion Source
To obtain relevant ion beams for the cyclotron a small 10 GHz ECR ion source
(Fig.1) has been built at HIL. ECR discharge takes place in the stainless steel chamber, 50 mm
inner diameter, 250 mm long. This chamber is an extension of a coaxial line, feeding RF to the
plasma, similarly to the Nanogan. The magnetic confinement of the plasma in radial direction is
obtained by the hexapol surrounding the chamber. This hexapol consists of 12 segments made of
NdFeB permanent magnets. Trough the 1 mm gap between the hexapol and the chamber tube a cooling
oil is pumped. The axial magnetic field is created by 8 water cooled coils. Each two coils are
supplied with a current from separate power supply. This configuration allows to obtain relevant
magnetic profile, tuned for the maximum of the beam current. The combination of the criogenic
and turbomolecular pump provides the vacuum of about 5x10^8 in the beam area.
Fig. 1. Schematic view of the ECR ion source. 1. coils 2. hexapol 3. plasma chamber 4. coaxial line
5. tuner 6. RF injection 7. exit hole 8. Einzel lens 9. yoke.
Main parameters of the ion source:
-
RF frequency: 9.6 GHz
-
extraction voltage: 10 kV
-
max. magnetic field on the axis: 6.5 kG
-
min. magnetic field on the axis: 2.4 kG
-
hexapole field on the chamber surface: 5.2 kG
-
RF power: up to 300 W
Tabela 1. Ion beams available from the Warsaw
ECR ion source, currents in
eµA
Ion/q |
+1 |
+2 |
+3 |
+4 |
+5 |
+6 |
+7 |
+8 |
+9 |
+10 |
+11 |
+12 |
+13 |
4He |
220 |
|
|
|
|
|
|
|
|
|
|
|
|
10B |
|
10 |
|
|
|
|
|
|
|
|
|
|
|
11B |
|
47 |
57 |
21 |
|
|
|
|
|
|
|
|
|
12C |
|
100 |
120 |
55 |
6 |
|
|
|
|
|
|
|
|
14N |
|
160 |
180 |
130 |
75 |
|
|
|
|
|
|
|
|
16O |
|
|
190 |
180 |
85 |
32 |
|
|
|
|
|
|
|
18O |
|
|
45 |
|
|
|
|
|
|
|
|
|
|
19F |
|
|
65 |
80 |
47 |
22 |
10 |
2 |
|
|
|
|
|
20Ne |
|
|
150 |
145 |
115 |
90 |
49 |
5 |
|
|
|
|
|
22Ne |
|
|
|
120 |
|
|
|
|
|
|
|
|
|
32S |
|
|
|
|
109 |
|
118 |
56 |
16 |
6 |
|
|
|
40Ar |
|
|
|
|
|
90 |
65 |
58 |
15 |
|
5 |
|
|
84Kr |
|
|
|
|
|
|
30 |
32 |
27 |
20 |
14 |
|
4 |
Fig.2. Example of the charge state distribution: sulfur optimized for S+7.
Fig.3. Examples of the ECR ion source possible applications (in red).
The Warsaw ECR source has been built under general supervision of
Dr Krzysztof Sudlitz (k.sudlitz@inetia.pl).
|