CHARACTERIZATION OF H- EXTRACTION FOR A MULTIPOLE ION-SOURCE LOCATED IN THE TAIL OF THE MAGNETIC-FIELD DISTRIBUTION - TYPE-III

Citation
Y. Oka et al., CHARACTERIZATION OF H- EXTRACTION FOR A MULTIPOLE ION-SOURCE LOCATED IN THE TAIL OF THE MAGNETIC-FIELD DISTRIBUTION - TYPE-III, Journal of vacuum science & technology. A. Vacuum, surfaces, and films, 12(6), 1994, pp. 3109-3114
Citations number
16
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics, Applied","Materials Science, Coatings & Films
ISSN journal
0734-2101
Volume
12
Issue
6
Year of publication
1994
Pages
3109 - 3114
Database
ISI
SICI code
0734-2101(1994)12:6<3109:COHEFA>2.0.ZU;2-J
Abstract
A magnetic multipole plasma source and the accelerator for H- ion sour ce is installed in the distribution of the externally imposed magnetic field which is quasiuniform over the plasma electrode. As the magneti c field of the permanent magnets in this geometry works not only as a so-called magnetic filter for electron cooling, but also as a deflecti on field to the accompanied beam electrons, there is a possibility for making the fabrication of the H- source simpler/easier due to no use of small magnets in the accelerator. The characteristics of the ion so urce such as H- extraction, optimization in the magnetic field, the pl asma parameters, etc. are investigated. The integrated magnetic flux o f 230-320 G cm should be determined by the condition which optimizes t he volume production in the source plasma. Achievable current density of H- is 6 mA/cm(2) with 15 keV at the target. Large amounts of the el ectrons, however, are accelerated altogether to a full energy. They ca n be stopped with a retarding potential. It is rather unusual that the positive-ion saturation current profile with the probe becomes more l ike inhomogeneous across the magnetic field. The results (of H- and G cm) are compared with ones for the different three types of the magnet arrangement.