Oxygen Radical Density Measurement in O2-N2 Mixture Gas Plasma by means of a Platinum Thin Wire

The measurement of oxygen radical density in O₂-N₂ mixture gas weakly ionized plasma by using a simple platinum made thin wire sensor has been carried out. The increased temperatures of the platinum wire caused by the released energy of the recombination reaction process of two oxygen radicals on the platinum surface have been measured by varying the nitrogen gas mixture ratio and compared with the oxygen radical densities theoretically calculated in the same plasma conditions. Moreover, the relation between the thin wire temperature and the oxygen radical densities has been also cross-checked by the quantitative measurement of oxygen radical densities using a quadrupole mass spectrometer. All these results made us possible to determine the oxygen radical density experimentally solely from the platinum wire temperature. The influence of ambient gas temperature on the radical density measurement has been also examined and discussed.