Advanced integrated stationary afterglow apparatus for study of recombination in He-Ar-H2 plasma

New Advanced Integrated Stationary Afterglow (AISA) apparatus was built to study the recombination in helium-hydrogen plasma. The plasma is generated in He (pressures 1 to 2.5 Torr) with small admixture of Ar and H-2 by a pulsed microwave generator with the pulse duration 2-5 ms and the repetition time 20, 40 and 60 ms. A Langmuir probe is used to measure the time evolution of the electron number density. The recombination coefficients are determined from the time evolution of the electron number density in the recombination-dominated stationary afterglow. The recombination of O-2(+) with electrons was used for validation of the probe results. The recombination in He buffered afterglow with an addition of Ar only is negligible and we observed only a decay due to the diffusion. With an addition of H-2, we observed a very slow recombination of H-3(+) ions with electrons; the obtained recombination rate coefficient alpha < 4 x 10(-8) cm(3)s(-1).