Abstract

The characteristics of a helium microwave plasma produced at atmospheric pressure have been studied by means of laser induced fluorescence and emission spectroscopy. The influence of nitrogen impurities on discharge parameters (electron density and gas temperature) has been studied together with the variation of the He metastable (23S and 21S) populations. A strong decrease of the He metastable densities for nitrogen concentrations as small as 1% was found. The dependence of the populations of nitrogen molecular and atomic species has been examined as a function of the electron density and nitrogen concentration in helium. Comparison with a theoretical model accounting for the presence of nitrogen in the discharge shows that Penning ionization by both atomic and molecular nitrogen play an important role on the metastable quenching.

Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call