Speaker
Description
Collisional radiative (CR) models are useful to analyze the dynamic process of excited states and are in favor of optical emission spectroscopy (OES) in negative hydrogen ion source plasma. In this paper, a CR model of atomic hydrogen containing excitation of H, dissociative excitation by H2 and dissociative recombination by H2+ is developed. The above three channels account for the main contribution for an excited H in cesium free negative hydrogen ion source. Then, the population and depopulation mechanisms of excited atomic hydrogen states are presented for each channel. Furthermore, the influence of electron energy distribution function with a depleted or overheated tail is discussed. Finally, above CR model is used to obtain plasma parameters by OES in hydrogen ICP discharge, with electron density 4.9E16 m-3 and electron temperature 2.2 eV at a source pressure of 2.3 Pa and power of 600 W.
