Ion source with low voltage extraction using glow discharge
Experimental results are given for a new type of plasma source and for the beam efficiency of a multi-aperture three-electrode extraction system at energy 500 to 1000 eV. This plasma source consists of a thin grid in front of a cathode and of a large cylindrical anode mounted close to the extraction electrode. High density, highly ionized, large uniform plasma is produced by glow discharge even with low discharge current. The plasma diameter (2 to 4 cm in diameter) is controlled by the position of line cusp field near the cathode. The densities of hydrogen plasma and argon plasma are more than 10$sup 12$/cm$sup 3$ and more than 10$sup 13$/cm$sup 3$, respectively. The temperatures of the plasmas are about 2 to 3 x 10$sup 40$K. This source is operated steady state at 0.5 A with ion energy of 0.5 to 1 keV. The multi-aperture electrodes are of copper 0.5 mm thick and 4 cm in diameter. 400 apertures are made by the photo- etching method. The extraction electrode is recessed. The ratio r/d of the radius of extraction aperture to the distance between the positive and negative electrode is varied. At an optimum ratio r/d the electrical efficiency is about 90 percent and the divergence of the beam is 5$sup 0$ in low ion beam current (about 150 mA). But in higher ion beam current (about 250 mA) the efficiency decreases. (auth)
- Research Organization:
- Ministry of International Trade and Industry, Tokyo; California Univ., Berkeley (USA). Lawrence Berkeley Lab.
- NSA Number:
- NSA-33-027200
- OSTI ID:
- 4006129
- Report Number(s):
- LBL-3399(Suppl.); CONF-741019-
- Resource Relation:
- Conference: Symposium on ion sources and formation of ion beams, Berkeley, California, USA, 22 Oct 1974; Other Information: Orig. Receipt Date: 30-JUN-76; Related Information: Proceedings of the second symposium on ion sources and formation of ion beams
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Electron
Ion & Molecular Beams & Reactions
640301* -Physics Research-Atomic
Molecular & Chemical Physics-Beams & Their Reactions
*ARGON IONS- BEAM PRODUCTION
*HYDROGEN IONS- BEAM PRODUCTION
*PENNING ION SOURCES- MODIFICATIONS
BEAM EXTRACTION
EFFICIENCY
ION BEAMS