Plasma neutralisation cathode.

摘要

A plasma compensation cathode comprises a casing (1) accommodating coaxially with its outlet hole (2) a hollow holder (3) and a thermal emitter (4) with a central passage (5), a layer (10) of material chemically inert at high temperatures to the materials of the holder and emitter being interposed therebetween. The central passage (5) is blind at the side of admission of gas, and is communicated with the interior of the holder (3) by way of a through passage (8) made in the wall of the thermal emitter (4) so that its axis intersects the axis of passage (5), and longitudinal grooves (9) made in the side surface of the thermal emitter (4) at the location of the inlet holes of the through passage (8). The holder (3) is embraced by heater (6) having a support ring (7) positioned in its midportion and secured in an insulation sleeve (18) separating the heater (6) from the coaxial heat screens (11) interconnected successively to define a sealed cavity (14) wherethrough the interior of the holder (3) communicates with the gas feeding pipe (13) secured in the casing (1) through the support insulator (17). Interposed between mechanical filters (16) and between holder (3) and pipe (13) is a getter (15). <IMAGE>