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RIKEN Accel. Próg. Rep. 24 (1990)

V. DEVELOPMENT OF ACCELERATOR FACILITIES

1. lon Accelerator Development

1. Test-Bench Performance of ECR lon Source (NEOMAFIOS)

E. Ikezawa, Y. Miyazawa, M. Hemmi, Y. Chiba, T. Chiba,

M. Kasę, M. Fujimaki, T. Aihara,* T. Ohki,* and H. Hasebe*

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.

B *»«>! rr>wcl

UH* f««d

u _ -V

• a

W • i i

l ft I

*4»

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.