Production of Negative Ions and Noise in Negative Ion Beams

Abstract

In a search for high current sources of low energy (≈100 ev) negative atomic ions of hydrogen and oxygen, five types of sources were examined. The most promising practical source for both ${\mathrm{H}}^{-}$ and ${\mathrm{O}}^{-}$ was found to be the dc glow discharge from which beams of ${10}^{-7\mathrm{}}$ ampere of either ion could be drawn. Hot cathode arc discharges yielded ${\mathrm{H}}^{-}$ currents of 7×${10}^{-8\mathrm{}}$ ampere. Rf discharges, hollow cathode discharges, and sources involving the Arnot effect seem inferior as high current sources.