Optical Emission Spectroscopic Measurement of Argon Low-Pressure Inductively Coupled Plasma Based on the Optimization Algorithm of Plasma Diagnostic Model

Previously, we reported an optimization algorithm based on a plasma diagnostic model for optical emission spectroscopic (OES) measurements. In this study, we improved the algorithm. In the improved algorithm, the dependence of unimodality of reduced population density on electron temperature, electron density, and electron energy distribution function (EEDF) was discussed. Furthermore, electron temperature, electron density, and EEDF of 10 Pa argon inductively coupled plasma were diagnosed to experimentally evaluate the proposed algorithm. The diagnosis results were compared with those of the line-pair method and excitation temperature conversion method. The reduced population density distribution, which was calculated under the condition of the result of the proposed method, was in good agreement with the experimental result by OES measurement, thereby demonstrating the reliability of our proposed method.