Optimization of H− production from a small multicusp ion source
| Autor: | W. B. Kunkel, S. R. Walther, Ka-Ngo Leung, C. A. Hauck |
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| Rok vydání: | 1989 |
| Předmět: | |
| Zdroj: | Review of Scientific Instruments. 60:531-538 |
| ISSN: | 1089-7623 0034-6748 |
| DOI: | 10.1063/1.1140359 |
| Popis: | A small multicusp source has been developed to generate volume‐produced H− ion beams in pulsed operation. To obtain high H− current densities (J−>250 mA/cm2), this source requires relatively high gas pressure and high discharge power. Experiments have been conducted to improve the arc and gas efficiencies, the beam pulse shape, and the H− to electron ratio in the extracted beam by optimizing the filter magnetic field, the thickness and axial position of the extraction aperture in the plasma electrode, and by mixing xenon or other elements with hydrogen in the discharge. The biggest improvement is achieved by adding cesium to the source, resulting in a fivefold increase in the extractable H− current and a substantial drop in the e/H− ratio. In order to improve the lifetime of the cathode, both filament and coaxial type LaB6 cathodes have been developed and have been operated successfully in this H− source. |
| Databáze: | OpenAIRE |
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