Maintenance of Helium Microwave-Induced Plasmas at Powers of Greater Than a Kilowatt for Chemical Analysis

A description of a helium kilowatt-plus microwave-induced plasma (KiP-MIP) system is presented. The output of a 2450 MHz system, with root mean square powers of up to 2.7 kW, are directed to a plasma torch within a TMoloresonator. The system is utilized to maintain plasmas of argon, nitrogen and helium; the latter showing unique potential for chemical analysis. Power waveforms and their effects on the plasmas are illustrated with “unfiltered” and “filtered” systems. Reflected and forward power are observed as the magnitude of the applied power is varied and the slide tuner is adjusted. Preliminary spectra from aqueous chloride and bromide are presented.