Extraction of a steady state electron beam from HCD plasmas for EBIS applications

Experiments to extract high brightness electron beams from hollow cathode discharge plasmas are now in progress. A unique feature of these plasmas, which in principle can facilitate the extraction of large current low emittance electron beams, is the existence of a relatively high energy electron population with a very narrow energy spread. This electron population was identified in a self-extraction experiment, which yielded a 35 eV, 600 mA electron beam with parallel energy spread of less than 0.5 eV. Application of a very modest extraction voltage yielded a steady state extracted electron beam current of 6.5 A of which 5.7 had a preacceleration parallel energy spread of no more than 0.25 eV. The end result of this endeavor would be an electron beam current to 6 A even though, preliminary results strongly suggest that much larger electron beam currents can be produced. 6 refs., 4 figs