Characterization of Argon-Helium Mixed Gas Inductively Coupled Plasma Based onSpectroscopic Analyses of the Argon and Zinc Emission Lines

In an Ar-He mixed gas inductively coupled plasma (ICP) the role of helium in the excitation of the zinc species was investigated through spectroscopic analyses on both the argon and zinc emission lines. Whereas the spectral widths of the argon lines were only slightly affected by helium addition, the emission intensities of the zinc lines apparently increased. Helium contributes to the increase in zinc excitation, though it causes a slight alternation of the electron density of the plasma. This results from an increment in the plasma temperatures in only the central channel where the zinc species is dominantly excited. These observations could suggest that helium acts as an energy carrier from the induction zone to the central channel of the ICP, due to the fairly high heat conductivity.