A Miniaturized XeCl Dielectric Barrier Discharge as a Source of Short Lived, Fast Decaying UV Radiation

Abstract

A dielectric barrier discharge (DBD) of coaxial geometry has been examined as source of intensive, short-lived UV radiation. A binary gas mixture consisting of 98% Xe + 2% Cl2 and a ternary composition of 96% Ne + 6% Xe + 0.2% HCl were investigated in the pressure range between 10 and 750 mbar. The discharge was excited by unipolar high voltage square pulses with amplitudes of 3 to 7 kV at a repetition rate of 100 Hz. UV radiation intensity is increased by combining 5 square pulses with a period of 1 μs each in one train (burst). Radiation decay on three orders of magnitude within 10 μs was obtained for both gas mixtures in burst mode. Maximum energy of the light pulse was the same for both gas mixtures and estimated as 40 nJ. It is shown that the optimum gas pressure for highest radiation intensity depends not only on gas composition but also on applied voltage and number of pulses in the train. A variation of the spectral band shape of XeCl emission during the pulse is detected.

Optimization of a Dielectric Barrier Discharge for Pulsed UV Emission of XeCl at 308 nm

“…The present work continues the investigations of [10] on the UV pulse characteristics of DBDs in Xe + Cl 2 gas mixtures. The main aim was to explore the opportunities of discharge optimization in terms of powerful and short UV light pulses.…”

“…It is worth to note that optimum pressure (p) reported in [10] is in the range of 150-250 mbar at 1.3 mm gas gap (d) for Xe+2%Cl 2 gas mixture whereas in [15] p is in the range of 400 -600 mbar at d = 8 mm for Xe + 0.4-10%Cl 2 gas mixtures. The disagreement in the optimum pd value might be due to dramatic differences in the shape of electrical pulses.…”

“…In case of pulsed lamps the experimental observation is different. The peak power measured for 200 ns voltage rise time [10] is more than three orders of magnitude lower then those measured for 4 -20 ns voltage pulses [15]. Therefore, it was assumed in [10] that waveforms with rise times as short as possible may improve the peak power of the radiation pulse.…”

“…In our previous work [10] two types of voltage waveforms had been applied: single square pulse and burst, where five single pulses were forming a voltage pulse train. It was shown that the optimum pressure with respect to maximum UV peak power depends on parameters of the voltage waveform.…”

“…As in DBDs the electrodes are protected by the dielectric, this discharge type provides the advantage of significantly increased lifetime. For this reason we will concentrate on investigations of DBD [10][11][12][13][14][15][16][17][18][19][22][23][24].…”