Dielectric Barrier Discharge lamp for decontamination purpose

Summary form only given. In this work, the correlation between the ozone production, the radiance measurements and the sporocidal efficacy of a Dielectric Barrier Discharge lamp (DBD) was studied. A DBD lamp initially designed for environmental lighting¹, was modified for biological decontamination. The prototype lamp (80mm x 120mm x 6mm) was made of two quartz layers covered by external metallic grids (electrodes). Between the layers, a gas mixture of Ne-Xe (1:1) is maintained at 500 mbar. A UV-C emission is generated by the inside coating of UV-C phosphor layer² (αCa2P2O7:Pr2%Na2%) when the lamp is fed with a pulsed power supply - with a voltage up to 2 kV with a 100 kHz maximum frequency. Sterile glass, polycarbonate plates and stainless steel samples were used as carriers. 10 μl Bacillus atrophaeus spore suspension containing c. 108 spores/ml was spotted on the carriers and exposed to the lamp emission - promptly for wet samples, and after overnight drying for dry samples. The exposure was conducted at a distance of 2 cm from the lamp and ranged from 10s to 300s. After the treatment, the spores were recovered in phosphate buffered saline and heat shocked. The survival degree was quantified using the standard plate counting technique on TSA plates and membrane filtration technique. SEM and TEM imaging was used to characterize the ultra-structural modifications produced by the exposure to the DBD lamp. First, we will present the ozone and radiance measurements for different voltages, frequencies and pressures. Then the results concerning the biocidal efficacy will be discussed.