A dielectric barrier Xe discharge lamp producing vacuum-ultraviolet radiation with high efficiency was investigated theoretically and experimentally. The cylindrical glass body of the lamp is equipped with thin strips of metal electrodes applied to diametrically opposite sides of the outer surface. We performed a simulation of discharge plasma properties based on one-dimensional fluid dynamics and also assessed the lamp characteristics experimentally. Simulation and experimental results are analysed and compared in terms of voltage and current characteristics, power input and discharge efficiency. Using the proposed lamp geometry and fast rise-time short square pulses of the driving voltage, an intrinsic discharge efficiency around 56% was predicted by simulation, and more than 60 lm W−1 lamp efficacy (for radiation converted into visible green light by phosphor coating) was demonstrated experimentally.

Operation of a Xe dielectric barrier discharge lamp producing 147–172 nm VUV radiation is investigated both theoretically and experimentally. Xe gas pressure varies between 100 and 300 mbar, and the glass body of the lamp is coated with LAP (green) phosphor to convert radiation into the visible part of the spectrum. Simulation results predict improved discharge efficiencies reaching 67% when excited by a fast rise-time, short pulse (∼200 ns) driving waveform. In this case most power deposited into the plasma efficiently produces excimers, while other energy dissipation processes (ion heating, e–Xe elastic collision) are kept at a low rate. Simulation and experimental results are compared in terms of discharge efficacy and show good agreement. A lamp efficacy value as high as 80 lm W−1 is demonstrated experimentally.

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In situ mass spectrometry of the near-surface composition—with special emphasis on radicals—has been carried out during diamond deposition from a microwave plasma in a CH4∕H2 mixture at 25 and 100mbars. The most abundant species in the former case are C2H2 and CH3, together giving 65% of the hydrocarbon content. At 100mbars, this value drops to 15%, while the C2H content rises to 76%. The factor of ∼8 increase in the C2H ratio is accompanied by a similar increase in the growth rate, indicating a major role of C2H in diamond growth.