Characterization of oxygen plasma with a fiber optic catalytic probe and determination of recombination coefficients

Fiber-optic catalytic probes were used to measure the neutral oxygen density in a postglow of a plasma reactor. Plasma was excited with an inductively coupled radio frequency generator with the frequency of 27.12 MHz and the power of 300 W. Plasma density was measured with a double Langmuir probe, while the density of neutral oxygen atoms was measured with four different fiber optic catalytic probes (Ni, Cu, Co, Nb), and NO titration. The measurements were performed at different pressure from 10 to 400 Pa. The density of neutral atoms was used to calculate recombination coefficients and their variations with plasma parameters. The results of neutral O-atom density and recombination coefficients were explained.