Development of a Thomson Scattering System for Micro-Discharge Plasmas

A laser Thomson scattering system was developed especially for measurement of electron temperature and electron density in a micro-discharge plasma. A triple-grating spectrometer was fabricated to suppress strong stray laser light, and allowed us to perform measurements at a position 0.3mm above a surface of a glass substrate which contained a pair of plane electrodes. Although the signal level was very low due to the small electron density and the very small scattering volume, Thomson scattering signals were detected clearly by using a photon-counting method. The temporal development of electron temperature and density was followed at a fixed point for a discharge in argon. The technique developed here is readily applicable to plasma display panel (PDP) discharges