High-Current Cold Cathode Field Emission Array for Electron Lens Applications

The luminosity of circular proton-antiproton colliders is limited by interactions of one beam upon the other, leading to beam blowup and other problems. Electron lenses have been shown to be effective at compensating for both long- and short-range beam-on-beam interactions. However, existing cathodes are inadequate for next-generation electron lenses because of their relatively slow rates of adjustment in cathode current and current density profile. In recent work, triggered carbon nanotube field emitters have been fabricated, which show great promise as cathodes for accelerator applications. In this project, the earlier limitations of such emitters will be addressed by coupling the carbon nanotubes with secondary current channel multipliers and an outer protective barrier, and by providing rapid low-level control of pixels composed of groups of emitters. Commercial Applications and other Benefits as described by the awardee: A cathode based on rapidly controlled field emission from carbon nanotubes, coupled with current channel multiplication, would be attractive due to its high current density, its ability to modulate the electron beam rapidly, and its ability to perform without a heater. In addition to the application for high energy physics, the novel cathode also should find use in telecommunications and radar, in both civilian and military systems