133
RIKEN Accel. Próg. Rep. 24 (1990)
An ECR (Electron Cyclotron Resonance) ion source NEOMAFIOS11 developed by the ion source development group of C.E.N.-G. (Centre d’Etudes Nucleaires de Grenoble) in France has the features of a smali size and Iow power consumption owing to the permanent magnets (FeNdB) used for both the hexapole field and mirror field. We purchased a set of NEOMAFIOS to replace the FIG source presently used in RILAC because the narrow space of RILAC and the limited power supply capacity of the ion source site. Figurę 1 shows the schematic drawing of the source and labie 1 shows its main parameters.
The performance test of NEOMAFIOS was car-ried out from March to July 1990 on a test bench capable of analyzing charge-states. Operations with 8 gaseous and 25 solid elements were tried and optimum operational parameters were searched for several ion species. In a usual operation, an RF power of less than 400 W is enough and the operat-ing pressure is 3 x 10“7 - 1 x 10 (l Torr at the extraction electrode. Ion charge-state spectra were mesured with one to several sets of operational parameters for each element. Figurę 2 shows a typical spectrum obtained with Pb.
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Table 1. Main parameters of the source.
Magnetic parameters | |
Materiał of permanent magnet |
FeNdB |
Magnetic field on axis |
0.21-0.52 T |
Electric power |
0 kW |
Microwave parameters | |
RF frequency |
8 GHz |
RF power injection |
Axial |
RF power |
1.7 kW max |
Finał tubę (Klystron) |
Thomson TH-2461 |
Electric power consumption |
5 kVA |
Yacuum window |
Al20:ł |
Dimensions | |
Chamber diameter |
66 mm |
Chamber length |
148 mm |
Ion outlet borę |
10 mm |
Extraction electrode borę |
16 mm |
Extraction gap |
45 mm |
Extraction voltage |
10 kV |
AnaJyzinR maRnet current (A)
Fig. 2. Charge-state spectrum with Pb optimized at an 18+ peak. RF power, 270 W; Beam extraction voltage, 10 kV; Mixing gas, 02.
Fig. 1. Schematic drawing of the source.
* Sumijyu Accelerator Service, Ltd.