OPTICAL CHARACTERIZATION OF 50 HZ ATMOSPHERIC PRESSURE SINGLE DIELECTRIC BARRIER DISCHARGE PLASMA

A low frequency (50 Hz) dielectric barrier discharge (DBD) system with a single dielectric cover on copper coil anode is designed to generate and sustain the micro-discharge plasma which is very practical for material processing applications. The DBD system is powered by a high tension ac source consisting of a conventional step up transformer and variac. The dielectric barriers (quartz and glass) between the conducting electrodes appreciably influences the discharge plasma characterized by optical emission spectroscopy technique. Using intensity ratio method, the electron temperature and electron number density are determined from recorded spectra as function of ac input voltage, type and thickness of dielectric barrier and inter-electrode gap. It is observed that both the electron temperature and electron number density increase with the increase in ac input voltage and 6r/d ratio, while a decreasing trend is observed with increase in inter-electrode gap.