The invention provides methods and apparatus for extracting ions, and further for producing neutrons from the extracted ions. In an aspect, there is provided a method for extracting ions involving the following step: in a vacuum chamber applying voltages to a spark gap between two electrodes comprising coatings of a hydrocarbon, each voltage sufficient to trigger a spark discharge in the gap sufficient to dissociate the hydrocarbon and extract therefrom hydrogen ions, wherein the hydrocarbon is a nonvolatile liquid sufficiently non-viscous to flow and re-coat holes in the coatings between each spark discharge.