Michael Wouters*, Joe Khachan, Ian Falconer and Brian James

Plasma Physics Department, School of Physics
University of Sydney, NSW, 2006, Australia
mjw@tip.csiro.au

Two photon laser induced fluorescence (LIF) is used to study the production and loss of H atoms in a pulsed microwave discharge in H2 over the pressure range 1 to 50 Torr. Absolute measurements of the H atom density are made at the end of the pulse. These measurements were calibrated using a new technique based on the decay rate of the LIF signal. The temporal variation of H-a emission during pulsing of the discharge is used to estimate the H2 dissociation rate, which compares well with the predictions of a one-dimensional model for the electron energy distribution function. This measurement also gives the wall recombination probability for H atoms, which is compared with that obtained by LIF measurement of the decay of the H atom density in the pulse afterglow.