Mass Spectrometry Of Neutrals And Positive Ions In He/Co2 Non-Equilibrium Atmospheric Plasma Jet

Neutral species and positive ions are measured by means of mass spectrometry in the effluent of the non-equilibrium atmospheric plasma jet operated in He/0%-1%CO2 gas mixture. The capacitively coupled plasma source is the predecessor of the known COST reference jet with identical performance and it is operated in a diffuse mode with gas temperature close to the room temperature. Threshold ionisation molecular beam mass spectrometry is used to measure absolute densities of CO, O-2, O and O-3 species. The CO molecules are generated with densities up to 2 x 10(15) cm(-3) at 1 W absorbed power. The O-2 density is similar to 6 times lower than the CO density and even lower than the O density at level of 4.5 x 10(14) cm(-3). The O-3 density is negligibly small at 4 x 10(12) cm(-3). The measured O-2, O-3 and O absolute densities add up to similar to 57% of the expected oxygen amount. The high O density could indicate that the vibrational excitation of CO2 is ineffective in this plasma and gas mixture, because O would otherwise react quickly with vibrationally excited CO2(v) to form CO and O-2, the low energy efficiency is in agreement with the possibly low vibrational excitation. The highest energy efficiency is just 5% with 1% conversion efficiency. Ion mass spectrometry have been used to measure positive and negative ions, where only positive ions have been detected. The ion with highest signal is theO2+More