Atomic oxygen production and exploration of reaction mechanisms in a He-O2 atmospheric pressure glow discharge torch

This article reports on the performance of a miniature APGD-t conceived for the production of reactive species participating in bio-applications. Two operating parameters were varied the plasma-forming gas flow rate (0.5-1.5 slm e) and the flow rate of O-2 (0-50 seem), which was injected downstream from the plasma-forming zone, and which was used as a source of reactive species. The production of reactive species (O) was optimized, and the air entrainment in the plasma jet was minimized for a He gas flow rate of 1-1.5 slm and an O-2/He volumetric ratio of 0.3 vol.-%. A survey of the possible reaction pathways in the afterglow plasma jet suggests that the reactive species present in the plasma afterglow, and possibly reaching a remote substrate are metastable He(2(3)S), ground state O, OH, O-2 (a(1)Delta g), O-2 (b(1)Sigma g(+)), N, N-2, N-2 and O-3.