Eduard A. Sosnin

Capacitive discharge exciplex lamps

Simple-geometry exciplex lamps of a novel type excited by a capacitive discharge (CD-excilamps) have been investigated. An efficient radiation has been obtained on KrBr*, KrCl*, XeBr*, XeCl* molecules and I* atom. The highest values of efficiency of various working molecules are approximately 10–18%. The lifetime of the operating gas mixture in KrCl*, XeCl*, I* and XeBr* exciplex lamps excited by a CD is above 1000 h. Owing to the above-mentioned characteristics, the exciplex lamps excited by a CD are supposed to be very promising for various applications.

Optical characteristics of cylindrical exciplex and excimer lamps excited by microwave radiation

The object of investigation is the optical characteristics of Br2, Cl2, XeBr, and XeCl excilamps excited by microwave radiation. The power of the microwave discharge is determined from a pressure jump in the bulb of the lamp. Conditions for the effective generation of XeCl* and XeBr* exciplexes in cylindrical lamps are found. The efficiency of generation of these exciplexes equals 7.2 and 7.8%, respectively.

UV and VUV efficient excilamps

Operating parameters of powerful excilamps with different discharge geometry pumped by glow discharges, high-pressure volume discharge with UV-preionization and barrier discharge are presented. Intense radiation of Ar2*, Kr2*, Xe2*, ArF*, KrBr*, Cl2, KrCl*, KrF*, XeI*, XeBr*, XeCl*, XeF*, I2 and IBR molecules was obtained in rare gas or in rare gas -- F2 (CH3Br, Cl2, HCl, I2, NF3) mixtures. Excilamps with high spatial uniformity of the output, narrow emission line and high gas life-time were developed. It was shown that efficiency of luminescence of exciplex molecules KrCl* of about 30% can be obtained in high- voltage glow discharge and positive column of glow discharge. Output at (lambda) approximately 222 and 308 nm up to 200 W from single excilamp and 500 W from three excilamps operating in parallel was demonstrated. It was shown that the efficiency of barrier discharge excilamps pumped by sinusoidal pulses several tens microseconds in duration can be sufficiently improved.

Runaway electron preionized diffuse discharges in atmospheric pressure air in point-to-point gaps in repetitive pulsed mode

Summary form only given. At present the sources of UV and VUV spontaneous radiation are vigorously investigated and enjoy wide use in different areas of science and technology. However, the devices developed to date and manufactured by the industry do not satisfy all requirements. For instance, to calibrate spectral instruments and optical elements requires point UV and VUV radiation sources with a radiating volume of ∼1 mm3 and a relatively high pulsed output power (above 1 W). Also of practical interest are the sources with nanosecond pulse duration operating in a pulse-periodic regime.

High power VUV and UV excilamps

In the present paper, the review of the basic results obtained at the Laboratory of Optical Radiation at High Current Electronics Institute SB RAS during 2007-2008 years is presented. Efficient radiation of Ar<inf>2</inf>, Kr<inf>2</inf>, Xe<inf>2</inf>, KrBr*, KrCl*, XeI*, XeBr*, XeCl*, Cl<inf>2</inf>* molecules and I atoms was obtained in rare gas or in rare gas - Br<inf>2</inf> (Cl<inf>2</inf>, I<inf>2</inf>) mixtures.

Inactivation of Shewanella putrefaciens by Plasma Activated Water

Plasma activated water (PAW) generated by atmospheric-pressure air microplasma arrays is a solution containing a variety of reactive species. Here we investigate the effects of different applied voltage and water-activated time on bactericidal activities against Shewanella putrefaciens (S. putrefaciens). Our measurements showed that the sterilization efficiency of S. putrefaciens by PAW could be up to 2.0 Log Reduction. Scanning electron microscopy image and DNA concentration measurement showed that the S. putrefaciens cells were damaged and deformed due to the PAW treatment. The physicochemical properties of PAW treated by different applied voltage and water-activated time were evaluated, including pH value, initial PAW temperature, and the concentrations of plasma-activated species, such as H2O2, NO3−, NO2−, and O3. Analysis indicates that the sterilization efficiency of S. putrefaciens treated by PAW was mainly determined by H2O2 concentration and pH value of PAW. This study provides a basis for the PAW potential applications in the disinfection of rotten food.

Apokamps produced by repetitive discharges in air

New experimental and computational data on apokamps produced by repetitive discharges in air, including a detailed description of the research techniques used, are presented. It has been shown that plasma bullets–streamers in apokamps at low frequencies could start not only from the bright offshoot but also directly from the discharge channel. The experimental and computational data demonstrate that the visual color of apokamp changes from blue to red as the intensity ratio of the second to the first positive nitrogen system decreases with the decreasing pressure.

NOx formation in apokamp-type atmospheric pressure plasma jets in air initiated by a pulse-repetitive discharge

The decomposition products of atmospheric pressure plasma of repetitive pulsed discharge in apokamp and corona modes were determined by optical and chemical methods. It is shown, that the decomposition products contain mainly nitrogen oxides NOx. A brief review of the plasma- and thermochemical reactions in the pulsed discharges was made. The review and experimental data allow us to explain the reactive oxygen species formation mechanisms in a potential discharge channel with apokamp. The possible applications of this plasma source for treatment of seeds of agricultural crops are discussed.

Presowing XeCl excilamp irradiation of crops: field research and prospects

Here we present research data demonstrating how crop seeds response to ultraviolet produced by a barrier-discharge XeCl* excilamp with a wavelength of 290–320 nm (82–88 %). The data show that presowing ultraviolet treatment is stimulatory to seed germination and plant growth. Ultraviolet treatment increases the seed germinability by 20–30 % and the plant fresh weight by 54 %, compared to untreated control samples, and provides a developed root system with long twisted segments. The research results are encouraging for upgrading the UV technology to larger-scale seed irradiation.

Application of excilamps in agriculture and animal breeding (review)

The paper provides a review of research data on applications of XeCl excilamps in agriculture and animal breeding. The data demonstrate a favorable effect of radiation produced by the excilamps on the fertility of animals (outbred mice and pigs) and on the growth of plants (flaxes, potatoes, carrots, cucumbers, conifers). Excilamp models adapted specially for use in stock-raising and grain storage complexes are now available. The research data obtained in 2012–2015 suggest that XeCl excilamps hold promise for prevention of diseases in indoor-housed pigs and for pre-sowing seed preparation.