Experimental characterization of a thermionic-arc discharge ionization device for flowing gases
| Autor: | Stelu Deaconu, S. T. Wu, Hugh W. Coleman |
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| Rok vydání: | 2002 |
| Předmět: | |
| Zdroj: | Review of Scientific Instruments. 73:91-97 |
| ISSN: | 1089-7623 0034-6748 |
| DOI: | 10.1063/1.1427415 |
| Popis: | The working characteristic of a new hollow cathode, thermionic-arc dc discharge ionization device was investigated experimentally. Under typical operating conditions the device produces a steady, field-free plasma plume by ionizing a flowing gas column. Experiments were performed with argon, nitrogen, and helium, the typical discharge pressures being 0.2–0.6 Torr. The discharge exploits the inherent stability of the point to plane geometry and the ionization efficiency of the hollow cathode. Electrically, the discharge is fed from a constant–voltage power supply and maintained below the interelectrode gap breakdown threshold. Thus the discharge current is given by Ohm’s law and is a function of the applied field and local plasma parameters. This modus operandi increases the ionization efficiency by maintaining a local thermal nonequilibrium in the discharge. The degree of nonequilibrium maintained in the plume downstream the cathode was higher in nitrogen (Te/Tgas≅8–10) than in argon (Te/Tgas≅3–4), and is... |
| Databáze: | OpenAIRE |
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