PRODUCTION AND LOSS OF H-ATOMS IN A MICROWAVE-DISCHARGE IN H-2

Two-photon laser-induced fluorescence (LIF) is used to study the produ ction and loss of H atoms in a pulsed microwave discharge in H-2 over the pressure range 1-50 Torr. Absolute measurements of the H atom dens ity are made at the end of the pulse. These measurements were calibrat ed using a new technique based on the decay rate of the LIF signal. Th e temporal variation of Ha emission during pulsing of the discharge is used to estimate the rate of dissociation of H-2, which compares well with the predictions of a one-dimensional model for the electron ener gy distribution function. This measurement also gives the wall recombi nation probability for H atoms, which is compared with that obtained b y LIF measurement of the decay df the H atom density in the pulse afte rglow.