| 摘要 |
<p>A plasma generator comprises a cathode structure (13) mounted within an evacuated chamber defined by a housing (11). The cathode structure comprises an inner filament (14) and an outer sleeve (15) coaxial therewith. Feed gas is supplied along a narrow annular gap (18) for example 0.25 mm. A heater current is passed along the filament (14) to produce electrons to establish a discharge between the cathode structure (13) and the anode housing (11). Feed gas passing along the gap (18) is highly ionised and forms an intense plasma (10). Control of operation is provided by the heater current in the filament (14) being varied to give the required emission temperature of the cathode structure (13).</p> |
