Multibeam honeycomb surface-plasma source with plasma injection from hollow cathodes

Abstract

The small model of scaled honeycomb surface-plasma source for intense multibeam H−(D−) ion production was studied. The increased sizes of the honeycomb cells (to 3×3 cm2) and of discharge layer thickness (to 1.5 cm) were tested. The plasma injection from the hollow hydrogen–cesium cathodes was used for a high-current semiplanotron discharge uniform operation at a low gas pressure. An optimal hydrogen pressure was about 1 Pa at maximal negative ion production. Extraction of H− ions from four emission apertures of 4×10 mm size each produces four elementary H− beams with intensity up to 100 mA each. No essential isotopic effect was found—the intensity of D− beams had about the same value (when discharge was operated in deuterium).