An Atmospheric Pressure Microwave Plasma Torch

Microwave plasma sources at atmospheric pressure have a variety of different applications and therefore are object of intense research. This paper covers the spectroscopic investigation of an atmospheric pressure microwave plasma torch and experiments concerning the abatement of the perfluorinated compounds CF4 and SF6. By means of optical emission spectroscopy the gas temperature of a humid air plasma was determined to 3600 K by using the AΣX 2 Π-transition of the OH radical. The electron temperature was determined to 5800 K by a Boltzmann-plot of atomic oxygen lines. The experiments concerning the decomposition of CF4 and SF6 showed that destruction and removal efficiencies (DRE) of over 99 % can be achieved and therefore the abatement of waste gases is a promising application of the presented microwave plasma torch.