Hydrogen negative ion source with LaB6 inserts : The 8th international conference on ion sources

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

The compact negative ion source having a semiplanotron discharge geometry and the two independently heated LaB6 cathode inserts was developed and studied. The hot LaB6 cathode insert supports discharge ignition and operation at low hydrogen pressure, while the cold one provides the glow discharge concentration in its vicinity. The stable production of H− beams with the current density in the emission hole in the range of about 0.1 A/cm2 was obtained in the pure hydrogen discharge. Negative ion yield at the different parts of the composite source cathode was measured. It was maximal in the glow region. An enhanced H− yield was recorded due to discharge concentration near the LaB6 inserts. LaB6 with a decreased work function does not produce a sizable income of surface-produced negative ions to the beam, extracted from the pure hydrogen discharge. The use of LaB6 inserts as a reliable source of electrons to form the discharge simplifies the surface-plasma source use. © 2000 American Institute of Physics.

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