HIGH-FREQUENCY INDUCTIVELY COUPLED PLASMA ANALYZER

摘要

PROBLEM TO BE SOLVED: To satisfy various characteristics required for a shield plate and to prevent deposition of salt by forming a shield plate with a nonoxidizing metal having a low electric resistance or its alloy. SOLUTION: A shield plate 60d located between an induction coil 9 and the plasma 8 generated by the high-frequency magnetic field formed around the induction coil 9 is made of gold which is a nonoxidizing metal having a low electric resistance. The shield plate 60d is formed into a cylindrical shape to surround the tip outer periphery of the outermost tube 6a of a plasma torch 6, or a flange section extending outward in the radial direction is provided at the tip of the plasma torch 6. The shield plate 60d is connected to the earth for high frequencies via a lead wire 6e. Deterioration by oxidation is prevented, conductivity, nonmagnetism and high heat resistance are provided, the plasma 8 and induction coil 9 are completely shielded electrostatically from each other, and ignition is facilitated.