A cylindrical dielectric barrier discharge (C-DBD) as a source of vacuum ultraviolet (VUV) radiation

High-pressure Dielectric Barrier Discharges (DBDs) produce non-equilibrium plasmas that can be used in a variety of applications. A new vacuum ultraviolet (VUV) plasma-based light source using a high-pressure cylindrical dielectric barrier discharge (C-DBD) excited by radio-frequency (rf) power was developed and characterized. The relative emission intensities of the Ne resonance lines and the Ne2* excimer continua in pure neon were studied as a function of pressure, rf power, and gas flow rate. Intense monochromatic H Lyman-alpha radiation at 121.6 nm is emitted from this source when operated in high-pressure neon with a small admixture of hydrogen. The emission spectra as a function of operating pressure, power, H2 concentration, and the flow rate were measured. Emission spectroscopy using the 2nd positive system of N2 was used to determine the rotational and the vibrational temperatures of the plasma species. Both temperatures were found to change as a function of the discharge conditions (pressure, power, concentration and excited frequency) reflecting changes in the plasma parameters and properties (electron energy distribution function, electron temperature, gas heating and cooling, alpha- vs. gamma-mode, relative importance of various collisional and radiative processes, etc.).