Ion energy distribution of plasma ions of a hollow cathode discharge in Ar + N$$_2$$ and Ar + O$$_2$$ gas mixtures

Abstract A hollow cathode discharge with a Ti cathode and a positively biased ring anode was operated in Ar + N$$_2$$ 2 or Ar + O$$_2$$ 2 gas mixtures. The energy distribution of plasma ions is investigated with the help of energy-resolved mass spectrometry. Singly and doubly charged Ar$$^+$$ + and Ar$$^{2+}$$ 2 + ions and molecular N$$_2^+$$ 2 + or O$$_2^+$$ 2 + ions are the most abundant ionic species. The kinetic energy of all plasma ions is enhanced by a positive anode voltage. Graphical abstract