Development of a new multi-plasma gas inductively coupled plasma torch

A new multi-plasma gas inductively coupled plasma (iCP) torch is designed and developed. With the new ICP torch, Ar, He, O₂, N₂, CO₂ and air plasma can be successfully generated in the atmospheric pressure. The torch has smaller area gas inlet and smaller distance between the gas inlet and the plasma generating region to generate an adequate vortex flow at the plasma generating region even with helium gas which has higher kinematic viscosity than other gases. Furthermore, helium has higher thermal conductivity than other gas and so the RF input power for helium ICP was limited by melting of the torch. In our helium ICP, the RF input power was limited only 800 W. To overcome this problem, the new torch has gas cooling system. The torch consists of coaxial three quartz glass tube and the carrier gas, the plasma gas and the cooling gas flow between the tubes. Helium ICP could be generated up to 1900 W at the plasma gas flow rate of 15 L/min. Torch melting was not observed with any plasma gases with air cooling. Results of spectroscopic measurements of the emission properties and the plasma temperatures of ICPs will be presented.