Absolute OH and O radical densities in effluent of a He/H2O micro-scaled atmospheric pressure plasma jet

摘要: The effluent of a micro-scaled atmospheric pressure plasma jet (μ-APPJ) operated in helium with admixtures water vapor ( ppm) has been analyzed by means cavity ring-down laser absorption spectroscopy and molecular beam mass spectrometry to measure hydroxyl (OH) radical densities, two-photon laser-induced fluorescence atomic oxygen (O) densities. Additionally, the performance bubbler as source feed gas carefully characterized calibrated. largest OH O densities , respectively, have measured at around 6000 ppm. highest selectivity is reached 1500 ppm, where density ~63% its maximum value 14 times larger than density. profiles distance variations are compared results 2D axially symmetric fluid model species transport reaction kinetics effluent. It shown that main loss radicals their mutual reaction. In case O, reactions other also be considered explain decay presented here provide additional information for understanding plasma-chemical processes non-equilibrium plasmas. They open way applying μ-APPJ He/H2O selective radicals.