Concentration of atomic hydrogen in the ground state in a CH4-H-2 microwave plasma

Ground state atomic hydrogen (H:1s S-2(1/2)) concentrations in the CH4-H-2 microwave plasma have been measured using actinometry. These measurements have been made over a wide range of plasma conditions including power inputs of 100-800 W and pressures of 0.5-60 Torr. A trace amount of argon vias added to serve as an inert reference gas for concurrent optical emission measurements, in which optical emission intensities from the H-gamma line (2p(2)P(0)-5d(2)D) at 434 nm and the Ar* line (4s'[1/2]degrees-4p'[1/2]) at 750 nm were recorded. (C) 1996 American Institute of Physics.