Determination of metastable densities in surface-wave neon plasma by self-absorption method

摘要

A novel type of surface-wave sustained microwave discharge in neon at low pressure was studied by optical emission spectroscopy. The spectra were measured in axial and azimuthal directions and analysed for an effect of self-absorption in order to determine the densities of neon metastable states 1s3 and 1s5. Homogeneous and axially dependent spatial intensity profiles were assumed in the calculations. Supporting "white light" absorption experiments with external LED light source were performed in order to prove the non-absorption character in azimuthal direction. The determined metastable densities depended on gas pressure ranging 0.10 - 0.46 ×10~(10) cm~(-3) and 3.3 - 4.3 ×10~(10) cm~(-3) for 1s_3 and 1s_5 state, respectively. A large in fluence of line-pair selection and column inhomogeneity on the resulting values was observed.