PLASMA DIAGNOSTICS OF AN ANALYTICAL GRIMM-TYPE GLOW-DISCHARGE IN ARGON AND IN NEON - LANGMUIR PROBE AND OPTICAL-EMISSION SPECTROMETRY MEASUREMENTS

Comparative investigations were performed on a Grimm-type glow dischar ge source by Langmuir probe measurements and by optical emission spect rometry. The Langmuir probe measurements yielded electron temperatures and number densities of electrons, whereas the optical emission spect rometry measurements resulted in data for excitation and ionization te mperatures of different species. The results confirm that there is no local thermal equilibrium in the discharge plasma. The operating-condi tions of the glow discharge source and also the working gas and the ca thode material were varied to investigate their influence on the plasm a parameters. The outcome of the plasma diagnostics will be used to im prove the modelling of relevant excitation and ionization processes by computer simulation. The major physical processes in the low pressure glow discharge plasma should be better understood if the analytical c apability of this spectrochemical excitation and ionization source has to be further enhanced.