Pulse operated multi-gas inductively coupled plasma source

Abstract

Summary form only given. A new atmospheric pulse operated multi-gas ICP (inductively coupled plasma) source is developed. With our multi-gas ICP source, not only Ar but He, O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , air and their mixture gas plasma can be stably generated in the atmospheric pressure. Furthermore, aqueous solutions can be introduced directly into the plasmas using common pneumatic nebulizers. To generate molecular gas plasma and to realize direct injection, higher RF power is necessary because dissociation of molecules (plasma gases or aqueous solutions) needs large input power. Therefore, the torch has external 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. When appropriate cooling gas species and flow rate were chosen, immixing of cooling gas and atmospheric air into the plasma can be reduced. In this study, to improve plasma properties (temperature, electron number density, emission intensity etc.) and to generate non-equilibrium plasma, pulsed operation is applied to multi-gas ICP and tested. A driving scheme by applying RF power input of rectangular waveform with a peak power of over 1 kW and a base power of around 300 W was adopted. Time resolved characteristics of atomic emission properties that include emission intensity and plasma excitation temperature of various plasmas are investigated