Search

Abstract— The design of a subnanosecond accelerator composed of three sections and a gas-filled diode and results of its testing are presented. The three sections of the accelerator are a double forming line, a ferrite line, and a line with a variable wave impedance. A beam current amplitude of ≈2.7 kA has been measured behind the anode foil at a pulse width at half-maximum of ≈370 ps. Using this accelerator and a standard spectrometer, Cherenkov radiation and pulsed cathodoluminescence have been investigated in KU-1 fused silica, polymethyl methacrylate, and KBr crystal samples.

Recommendations are given on designing thermosiphons (TS) prepared on the basis of the experience that the authors gained in designing more than 4000 TSs for heat-recovery steam generators and the results of long-term investigations and tests carried out to study thermohydraulic and corrosion processes in vertical and inclined TSs filled with steam-water mixture. The results of similar studies performed by other authors are analyzed. References are given to the regulations on the design of heat transfer equipment for thermal and nuclear power stations. The requirements for TS construction materials, the degree of TS filling with water, and the TS vacuum level are outlined. Whether the evacuation of TS may be abandoned was assessed. Measures are proposed to prevent depressurization on water freezing in TSs. Recommendations are given on the calculation of thermohydraulic characteristics and steam-and-gas distribution in vertical or inclined TSs. The conditions of displacement by a steam flow of noncondensable gases, including air, to the top of the condensation zone in a thermosiphon are considered. Various regimes of axial heat transport and heat transfer are described for pure steam condensation (including film condensation, bubble condensation, distribution of different regimes of steam condensation, and condensate cooling along the height of the condensation zone during “flooding”). Heat transfer in the steam condensation from an air-steam mixture (the diffusion component of thermal resistance), maximum power, and the conditions for poorer cooling of the TS heating zone (“flooding,” steam separation at the upper generatrix of the heating zone in an inclined thermosiphon) are examined. Thermosiphons feature a countercurrent flow of steam and its condensate in a single flow with the same mass flowrates. Hence, a special case of “flooding” affecting the maximum power of the thermosiphon, the effect of the incoming steam flow on the heat transfer rate during film condensation, steam-and-gas distribution in a top-plugged channel, corrosion processes in thermosiphons, and hydrogen diffusion through the thermosiphon wall should also be studied.

—This paper describes the design and parameters of a nanosecond accelerator with an additional transmission line that has variable wave impedance and a gas-filled diode. The possibility of controlling the beam current parameters by changing the air pressure in the diode is shown. Behind the anode foil, at a half-maximum pulse width of ≈1.3 ns and an electron energy of up to 350 keV, the beam current amplitude was ≈700 A. Vavilov–Cherenkov radiation spectra and oscillograms were recorded when were excited by the electron beam of this accelerator. quartz, sapphire, and synthetic diamond were excited by the electron beam of this accelerator.

Представлены результаты имитационного моделирования , иллю стрирующие влияние законов движения самолетов - носителей РСА ( активного и пассивного ) относительно исследуемого участка поверхности Земли на разре шающую способность результирующей бистатической радиолокационной систе мы . Изложены методы расчета вторичных информационных массивов для син теза изображения , включая семейство опорных функций , на основе первичной навигационной информации , представлены как формулы , так и результаты моде лирования . Выявлены специфические черты бистатических обзоров общей кон фигурации по сравнению с моностатическими . Проиллюстрирована процедура синтеза применительно к самолетной бистатике .

Cherenkov radiation is widely used to register charged particles with high energy. This paper describes the design and parameters of an electrons accelerator, as well as the results of studies of the spectra and amplitude-time characteristics of sapphire and quartz KU1 radiation under the excitation of electrons with an energy of up to 350 keV. It was shown that in the UV and visible spectral regions a wide band is recorded, the intensity of which increases with decreasing wavelength. It was established that the duration and shape of the radiation pulse of this band coincides with the pulse of the electron beam. All this allows us to attribute the registered emission to the Cherenkov radiation.

Results of experimental determination of the average heat transfer coefficient upon condensation of pure steam αc and steam from air–steam mixture αas.m in tubes of a large-scale model of the emergency cooling heat exchanger in the system of passive heat removal through steam generators of AES-2006 project at Leningrad II NPP are presented. The model contained 16 parallel tubes with a diameter of 16 × 2 mm and a length of 2.9 m connected to the upper steam distributing and lower condensate gathering horizontal collectors; the distance between their axes was 2.28 m. The tube segments were vertical, horizontal, or inclined. The internal diameter of the collectors was 40 or 60 mm. The model was placed in the lower part of a tank with a height of 6.5 m and a volume of 5.85 m3 filled with boiling water at atmospheric pressure. The experimental parameters were as follows: pressure range 0.43–7.77 MPa, condensate Reynolds number Ref = (0.87–9.3) × 103, and average air volume fraction at the segment with air–steam mixture 0.18–0.85. The studies showed that nonuniformity of static pressure distribution along the steam-distributing collector strongly influences the reduction of αc value (ejecting effect). The agreement between experimental and calculated according to statutory guidelines values of αc for vertical tubes is achieved if the dynamic head of the steam flow at the input of the steam-distributing collector does not exceed 1 kPa. Equations for calculation of the diffusion heat transfer coefficient at steam condensation from the air–steam mixture αas.m on the internal tube surface are proposed. In the considered conditions, air is completely displaced by steam flow from the upper to the lower part of the tubes. The boundary between these regions is characterized by an average reduced steam velocity through this cross section of 1.6 ± 0.4 m/s. Above the boundary cross section, it is recommended to calculate αc. according to [1].

The conditions for forming subnanosecond electron beams with adjustable pulse durations in the vacuum-diode mode using a SLEP-150 generator were investigated. It was confirmed that the residual air pressure in the diode (∼0.1 Torr or less) does not affect the amplitude and duration of the beam current when using a nanosecond voltage pulse. It was shown that increasing the air pressure in the diode from 0.1 to 6.0 Torr leads to a decrease in the full width at half-maximum (FWHM) duration of the electron-beam current from ∼1.00 to 0.18 ns and a shorter delay of the beam generation moment relative to the voltage-pulse rise time. It was established that the amplitude of the first peak of the beam current behind the foil remained constant under these conditions. Its value was ≥400 A. It is shown that when the interelectrode gaps are optimal for vacuum diodes, the pulse duration at elevated pressures shortens due to the gap breakdown for a time of ≤200 ps.

The conditions for the generation of subnanosecond and picosecond electron beams with a tunable pulse width are studied on an SLEP-150 generator with a tubular cathode at a voltage pulse rise time of 0.3 ns. The width and shape of the beam current pulse are varied by varying the pressure and gas kind in the diode. It is shown that in the vacuum diode mode, the beam current rise time decreases from ${\sim}{0.5}$ to ${\sim}{\rm 0.2}~{\rm ns}$ as the interelectrode gap is decreased from 12 to ${\sim}{\rm 2}~{\rm mm}$ . It is found that with a 3-mm interelectrode gap, increasing the air pressure in the diode of the SLEP-150 generator from 0.1 to 6 torr decreases the full width at half maximum (FWHM) of the current pulse from ${\sim}{1}$ to 0.18 ns, with the beam current amplitude greater than 400 A and the beam current rise time less delayed with respect to the voltage pulse rise time. It is confirmed that with a nanosecond voltage pulse, the residual pressure of helium, nitrogen, and air in the diode ( ${\sim}{0.1}$ torr or less) does not affect the beam current amplitude and pulse width. At low pressure of air in the gas diode, the attained beam current density at a beam current pulse FWHM of 0.18-1 and ${\sim}{\rm 0.1}~{\rm ns}$ is ${\sim}{500}$ and ${\sim}{100}~{\rm A}/{\rm cm}^{2}$ , respectively.

The dependences of the electron beam intensity and X-ray dose on the thickness of metal foils (Al, Cu) in a nanosecond discharge initiated in atmospheric-pressure air are studied theoretically and experimentally. Calculated curves of electron beam attenuation in aluminum and X-ray dose attenuation in copper agree well with experimental data. It is found that the amplitude of a super-short avalanche electron beam and the X-ray exposure dose reach maximal values at different values of the interelectrode gap. When the length of the cathode’s edge with a small radius of curvature increases, an interelectrode gap maximizing the amplitude of the runaway electron current shrinks.

A high-pressure CO{sub 2} laser with a discharge initiated by an electron beam of sub-nanosecond duration in the laser gas mixture at a pressure up to 5 atm is fabricated. For the 20-ns pulses the energy from the active volume {approx} 4 cm{sup 3} amounted to 40 mJ. The laser operation at a pulse repetition rate up to 5 Hz is demonstrated. In the gas mixture CO{sub 2}:N{sub 2}:He = 1:1:6 at a pressure 5 atm, the specific energy deposition of {approx} 0.07 J cm{sup -3} atm{sup -1} is obtained in the process of a non-self-sustained discharge with ionisation amplification.

The results of experimental investigation of choking in vertical tubes with diameter 20, 30, and 40 mm and 19-rod assembly with pressure 0.6–4.1 MPa in the absence of directed circulation of the coolant and with water level above the section under study are presented. Previously determined correlations for determining the counterflow of the phases during choking for a wide range of pressure and diameter of the sections are refined. The results of calculations, performed with the KORSAR and RELAP5/MOD3.2, of choking in experimental sections are presented. Comparative analysis has revealed discrepancies between the computations and the experimental data. It is concluded on the basis of the results obtained that the models of choking for the tested codes need additional work with a correction of relations for the flow rate of the phases. It is recommended that this be done using the correlations obtained in the course of the present experimental study.

The results of experimental studies of a passive system for removing heat through steam generators which were performed on a large-scale (1/110) stand at the Scientific-Industrial Association for Research and Design of Power-Generation Equipment (NPO TsKTI, St. Petersburg) are presented. The experiments show that the system performs reliably and effectively as designed. The experimental data were used to verify the thermohydraulic codes KORSAR and SOKRAT, which are used to model the thermohydraulic processes in the system at the Leningradskaya nuclear power plant.

Electrochemical dissolution of an Al-In-Sn alloy in 2–4 M NaOH solutions containing 0–3 M of sodium aluminate at temperatures of 40 and 75°C was studied by measuring potentiodynamic curves and chronopotentiograms.

We present the results from comprehensive experimental investigations on determining the void fraction φ during concurrent upward and countercurrent motion of steam—water mixture in rod assemblies and fuel-rod cooling conditions when the fuel rods are partially dried. The problems are solved as applied to the conditions of an accident involving a small or medium leak.

Electron beam formation in krypton, neon, helium, and nitrogen at elevated pressures are experimentally investigated. It is shown that, when the krypton, neon, and helium pressures are varied, respectively, from 70 to 760 Torr, from 150 to 760 Torr, and from 300 to 4560 Torr, runaway electrons are beamed at the instant the plasma in the discharge gap approaches the anode and the nonlocal criterion for electron runaway is fulfilled. The fast-electron simulation of discharge gap preionization is performed. The simulation data demonstrate that preionization in the discharge gap is provided if the voltage pulse rise time is shorter than a nanosecond under atmospheric pressure.

Luminescence of crystals of natural spodumene and natural diamond of the type IIa is studied upon excitation by a laser at a wavelength of 222 nm and by a subnanosecond avalanche electron beam (SAEB) formed in air at the atmospheric pressure. The photoluminescence spectra of spodumene and diamond are shown to exhibit additional bands, which are absent upon SAEB excitation. It is demonstrated that SAEB excitation allows one to analyse various crystals under normal conditions without using any vacuum equipment.

It is shown that a volume discharge is formed in a nonuniform electric field for the short leading edge of a voltage pulse and nanosecond pulse duration without any additional preionisation source in various gases at pressures higher than atmospheric (6 atm in helium and 3 atm in nitrogen). Lasing at atomic transitions in Xe is obtained in an Ar—Xe mixture under a pressure of 1.2 atm for an active length of 1.5 cm. A record-high specific power input (more than 0.8 GW cm-3 under a pressure 1 atm in air) is realised in the volume discharge stage. The volume discharge is formed due to preionisation of the discharge gap by fast electrons accelerated due to amplification of the electric field in the cathode region and in the gap. In a nonuniform electric field, volume discharge is realised under a quasistationary voltage from 10 to 180 kV across the gap, at a pulse repetition rate of up to 160 Hz and for various discharge gap geometries.

Lasers on the second positive nitrogen system (the C3Πu—B3Πg electronic band, λ=337.1 and 357.7 nm) are studied. Mixtures of nitrogen with electronegative gases (SF6 and NF3) are pumped by transverse and longitudinal discharges. The amplitude—time and spectral characteristics of a laser pumped from capacitive and inductive energy storage units are measured. The output energies of the laser pumped by a transverse discharge from a capacitive and inductive storage units are 17 and 18.4 mJ, respectively. It is shown that the mean output energy in N2—NF3 mixtures continues to increase at higher pulse repetition rates than in nitrogen. Under the pumping by a transverse discharge, two-peak 357.7-nm lasing with a total pulse duration of >40 ns is achieved. It is established that adding SF6 to the mixture enhances the output power of a longitudinal-discharge-pumped nitrogen laser.

Electrochemical dissolution of aluminum alloyed with tin, indium, and lead in a NaOH solution in the concentration range 4.4–12.0 M at 75°C was studied by the method of chronopotential and current-voltage curves. The influence exerted by alloying elements on the electrochemical parameters of the process was revealed.

Conditions are studied under which an electron beam and a volume discharge with a subnanosecond rise time of a voltage pulse are produced in air under atmospheric pressure. It is shown that the electron beam appears in a gas-filled diode at the front of the voltage pulse in ∼0.5 ns, has a half-intensity duration of ≤0.4 ns and an average electron energy of ∼0.6 of the voltage across the gas-filled diode, and terminates when the voltage across the gap reaches its maximum value. The electron beam with an average electron energy of 60 to 80 keV and a current amplitude of ≥70 A is obtained. It is assumed that the electron beam is formed from electrons produced in the gap due to gas ionization by fast electrons when the intensity of the field between the front of the expanding plasma cloud and the anode reaches its critical value. A nanosecond volume discharge with a specific power input of ≥400 MW/cm3, a density of the discharge current at the anode of up to 3 kA/cm2, and specific energy deposition of ∼1 J/cm3 over 3 to 5 ns is created.

This article reports on experimental studies of subnanosecond electron beams formed in air under atmospheric pressure. An electron beam with an amplitude of ∼170 A with a duration at FWHM of ∼0.3 ns has been obtained. Based on beam temporal characteristics and discharge spatial characteristics, the critical fields were supposed to be reached at plasma approach to anode. Simultaneously, the sharp high-energy pulse of e-beam current is generated. Of critical importance is the cathode type and occurrence on the cathode of plasma protrusions. It is shown that to get maximum amplitude of the electron beam in the gas diode, the discharge in the gas diode should be volumetric.

Experiments are performed on the formation of coloured dots of a submillimetre size on the titanium foil surface irradiated by pulsed IR lasers. It is shown that the parameters of laser pulses can be selected so that the dots produced on the titanium foil surface will change their colour from yellow to blue with increasing exposure time. The threshold laser power densities required for the formation of contrast coloured dots on the titanium foil surface irradiated by laser pulses with low repetition rates are estimated as ~1.5 × 103 J cm-2 for a 1.73-μm Xe laser and ~2.3 × 103 J cm-2 for a 10.6-μm CO2 laser.

The formation of a beam of runaway electrons in a diode filled with helium at a pressure from 0.1 to 760 Torr was studied under conditions of a pulsed ≈4 ns) high ≈200 kV) voltage applied to the discharge gap. Both theoretical results and experimental data indicate that the electron beam is generated both at a large strength of the electric field, when the fraction of runaway electrons is large, and in a field of low strength, where intensive electron multiplication takes place. In the latter case, a high current can be obtained despite a small fraction of runaway electrons relative to their total number. The electron beams obtained in the helium-filled diode had a current amplitude of up to 140 A (corresponding to a current density above 10 A/cm2) at an electron energy of ∼150 keV.

The interaction of Xe (λ ∼ 1.73 μm) and XeCl (0.308 μm) laser radiation with surfaces of metal and TiN-ceramic coatings on glass and steel substrates has been studied. Correlation between parameters of surface erosion versus laser-specific energy was investigated. Monitoring of laser-induced erosion on smooth polished surfaces was performed using optical microscopy. The correlation has been revealed between characteristic zones of thin coatings damaged by irradiation and energy distribution over the laser beam cross section allowing evaluation of defects and adhesion of coatings. The interaction of pulsed periodical CO2 (λ ∼ 10.6 μm), and Xe (λ ∼ 1.73 μm) laser radiation with surfaces of teflon (polytetrafluoroethylene—PTFE) has been studied. Monitoring of erosion track on surfaces was performed through optical microscopy. It has been shown that at pulsed periodical CO2-radiation interaction with teflon the sputtering of polymer with formation of submicron-size particles occurs. Dependencies of particle sizes, form, and sputtering velocity on laser pulse duration and target temperature have been obtained.

An experimental investigation is performed of the critical heat flux in vertical channels in the absence of circulation of heat-transfer agent through the lower cross section. Experiments are performed in tubes 30, 40, and 80 mm in diameter, as well as in 19- and 40-rod assemblies. Equations are suggested for the calculation of critical power, which are valid in a wide range of the geometric and process parameters, including at a low pressure.

An experimental investigation is performed of countercurrent flow of steam and water through perforated plates in the pressure rangeP = 0.6-4.0 MPa. An equation is suggested that describes the correlation between the countercurrent flow rates under conditions of “flooding.” The experimental results are compared with the data of previous studies. The effect of the geometric and process parameters on the processes involved is treated.

Countercurrent flow of gas and liquid in vertical tubes is investigated. Processes that occur under various conditions of flow (including the “flooding” mode) are treated. Equations are suggested that describing the hydrodynamic characteristics of countercurrent two-phase flow.

A photoreactor developed on the basis of a Xe2 excilamp with a power of ∼10 W (with a power density of 15 mW/cm2 emitted from a surface of ∼700 cm2), which can operate in liquids and gases at a pressure of up to 40 atm, and a multifunctional cell with an active volume of ∼760 cm3 is described. Data on water photolysis in a natural gas exposed to VUV radiation with λ=172 nm are presented.

The objective of the work is to study the beam current amplitude and pulse width at a voltage pulse rise time of -0.3 ns for interelectrode gaps of differing width in a diode pumped down to a pressure of about 0.01 Torr and filled with different gases (air, nitrogen, and helium). SLEP-150 generator with a tubular cathode was used. The conducted studies show that with subnanosecond voltage pulse rise times, it is possible to gradually vary the FWHM of the beam current pulse over a wide range. The FWHM and shape of the beam current pulse was varied by varying the pressure and gas kind in the diode. It is shown that in the vacuum diode mode, the beam current rise time decreases from 0.5 to 0.2 ns as the interelectrode gap is decreased from 12 to 2 mm. It is found that with a 3-mm interelectrode gap, increasing the air pressure in the diode of the SLEP-150 generator from 0.1 to 6 Torr decreases the FWHM of the current pulse from 1 to 0.18 ns, with the beam current amplitude greater than 400 A and the beam current rise time less delayed with respect to the voltage pulse rise time. The attained beam current density at a beam current pulse width of 0.18-1 and 0.1 ns is 500 and 100 A/cm2, respectively.

Subnanosecond electron beams can be formed in gas-filled diodes at high pressures (up to 6 and 4 bar in helium and nitrogen, respectively). In a diode filled with air at atmospheric pressure, a beam current amplitude above 240 A was obtained at a pulse duration (FWHM) of ∼0.2 s and a beam current density of ∼40 A/cm2.

An atmospheric-pressure CO2 laser with an electron-beam-initiated discharge produced in a working mixture is developed. The laser output energy of 18 mJ from a ~6-cm3 active volume is achieved. The laser operation with a pulse repetition rate of up to 5 Hz is demonstrated. The specific energy deposit of ~0.1 J cm-3 is obtained in the CO2:N2:He = 1:1:4 gas mixture at the atmospheric pressure during a pulsed nonself-sustained discharge with ionisation amplification.

We have studied the conditions for the formation of a pulsed beam of runaway electrons in a diode filled with air at atmospheric pressure, whereby the current and voltage pulses in the system were measured with a subnanosecond time resolution. It is experimentally demonstrated for the first time that the electron beam appears on the leading front of the voltage pulse at a relatively small voltage on the discharge gap. At atmospheric pressure, a full width at half maximum of the current pulse does not exceed 0.3 ns.

We have studied the electron beam formation in a diode filled with a molecular gas at atmospheric pressure. A beam current amplitude of up to ∼20 A at an electron energy of ∼70 keV was obtained in an air-filled diode. It is suggested that the main fraction of runaway electrons at low initial values of the parameter E/p (∼0.1 kV/(cm Torr)) is formed in the space between cathode plasma and anode. As the plasma spreads from cathode to anode, the electric field strength between the plasma front and anode increases and the E/p value reaches a critical level.

A technique for determining the amplitude and time parameters of pulsed electron beams is proposed. Using this technique, it is possible to measure weak currents. It is based on the non-self-sustained discharge initiated by the electron beam under investigation. The experimental results are presented for two electron beams formed in a gas-filled diode at the atmospheric pressure of air, nitrogen, a mixture of CO2 : N2 : He = 1 : 1 : 3, or helium and ejected through a foil or grid.

The design of a repetitively pulsed HF(DF) gas-discharge laser with an active-medium volume of 60 × 2.3 × 1.2 cm3, a pulse radiation energy of 1.6 (1.2) J, and a pulse repetition rate of 1–2 Hz is described. A zeolite-based absorber is used to stabilize the energy characteristics of the laser operating without the forced circulation of the laser mixture. An energy decrease by 50% after ∼103 laser shots is obtained at a pulse repetition rate of 1 Hz.

Strains of Trichoderma spp., producing L-lysine-alpha-oxidase, prospective in chemotherapy of malignant tumors, were studied. The best results of the enzyme biosynthesis were observed on the wheat bran medium. When grown on the media with various pH levels, the strains showed different spectra of the L-aminooxidase activity. The highest activity of the strains was recorded with respect to destruction of L-lysine. The lysine-producing organism Brevibacterium sp. induced L-lysine-alpha-oxidase activity in Trichoderma spp.

Acute toxicity of L-lysine-alpha-oxidase, an antitumor enzyme of fungal origin was studied. After intravenous administration in a dose of 3000 U/kg the substance induced no signs of intoxication in the laboratory animals or their death. Direct dependence of the vessel permeability increase on the enzyme concentration was determined. In experiments on rabbits and guinea pigs L-lysine-alpha-oxidase showed no local irritating effect.

Positive effect of local treatment with L-lysine-a-oxidase on the course of herpes genital infection was demonstrated on guinea pigs even after the appearance of infection symptoms. In animals treated with L-lysine-a-oxidase, the severity of the disease, virus reproduction and virus-induced changes in cells were significantly less pronounced than in untreated animals. The preparations exerted no toxic effects.

A high-pressure CO2 laser with a discharge initiated by a subnanosecond electron beam formed in the laser operating medium under pressure 5 atm. Radiation energy of 40 mJ in active volume of ~ 4 cm3 at radiation duration of 20 ns has been obtained. Laser operation at pulse repetition rate (p.r.r.) of up to 5 Hz has been demonstrated. Specific energy input of ~0,07 J/cm3. atm have been realized in laser operating gas mixture CO2:N2:He = 1:1:6 under pressure of 5 atm on the course of a pulsed non-sustained discharge with pre-ionization.© (2006) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

In HIV-infected MT-4 cells,l-lysine-α-oxidase, an inhibitor of HIV reproduction, selectively inhibits the synthesis of histone proteins, including 18K antigen (H2B histone). This protein is the target for autoimmune suppression of helper T cells. The enzyme has a low effect on the synthesis of other proteins and DNA. In addition to 18K antigen,l-lysine-α-oxidase suppresses the synthesis of high-molecular-weight proteins (270, 220, 140, 100, 75, 70, and 60 kD).

Teflon plate is irradiated by pulsed CO/sub 2/ laser. A crater with even edges without traces of melt or blackening was formed after irradiation of the teflon plate surface by focussed pulsed radiation of CO/sub 2/-laser with p.r.r. of /spl sim/1 Hz. Increasing of PTFE surface temperature resulted in increase of efficiency of teflon mass removed from the crater. Increasing of teflon target surface temperature or laser pulse duration results in greater amount of PTFE mass sputtered per shot, increase in particle sizes and appearance of fiber-like formations. Teflon sputtering velocities and powder particles distribution by size at pulse duration of 100 ns and 15 /spl mu/s and specific power of 10/sup 8/ and 10/sup 6/ W/cm/sup 2/, correspondingly, have been define.

In this paper, it is suggested to use pulsed laser radiation to define adhesion of thin metallic films to the substrate and surface defects detection. The preliminary experimental data on Xe- and XeCl-lasers interaction with thin films of metals deposited on glass using technology of vacuum-arc evaporation are presented in the paper. Threshold laser radiation power densities necessary for film detachment from the substrate are determined. Thus, a possibility of testing of thin film adhesion by focused pulsed laser irradiation with known power distribution over cross-section has been demonstrated.

It has been shown that a volume discharge is forming in a non-uniform electric field at a short voltage pulse rise and pulse nanosecond duration without preionization in different gases under pressures above atmospheric (helium 6 atm, nitrogen 3 atm).

It has been shown that the use of gas diodes with cathode electric field enhancement and voltage pulses having a short leading edge allow to form high-current subnanosecond electron beams. An electron beam appears at voltage pulse leading edge with duration at FWHM not more than 0.3 ns. On the beam current termination the discharge is usually continued in a quasi-stationary mode having a volume character. With a diode filled in with air under atmospheric pressure, beam current amplitude over 240 A at a pulse duration at FWHM of 0.2 ns and current density of 40 A/cm 2 was obtained. It has been also shown that at a smal l gas diode inductance the subnanosecond electron beams are formed in various gases in a wide pressure range (up to 6 atm in helium, and up to 4 atm in nitrogen). It has been established that with the new method an electron beam is formed due to critical field reached between an anode and plasma propagating from a cathode. Key words: e-beam, running electrons, gas diode, volume discharge

Atmosphere pressure CO2-laser with e-beam initiated disch arge formed in laser operating mixture has been created. Energy of radiation as 18 mJ in active volume of ~6 cm3 has been obtained. Laser operation at pulse repetition rate of up to 5 Hz was demonstrated. Specific energy input as ~0.1 J/cm3 was realized in gas mixture CO2:N2:He = 1:1:4 under atmosphere pressure in the process of a pulsed non-self-sustained discharge with ionized amplification. This method of discharge initiation is rather promising for creation of short-pulse high-pressure lasers.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The formation of a beam of runaway electrons in a diode filled with helium at a pressure from 0.1 to 760 Torr was studied under conditions of a pulsed (4 ns) high (200 kV) voltage applied to the discharge gap. The experimental data results indicate that the electron beam is generated either at a large strength of electric field, when the fraction of runaway electrons is large, or in the field of low strength, where intensive electron multiplication takes place. In the latter case, cathode plasma propagates to anode at high velocity, at that with electrical field distribution in gas diode area the critical value of E/p is reached either due to geometric quotient leading to formation of nanosecond and subnanosecond electron beams. The electron beams obtained in the helium-filled diode had the current amplitude of up to 200 A (corresponding to the current density above 20 A/cm2) at electron energy of ~130 keV.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

This paper reports on experimental study of subnanosecond e-beam formed in air under atmospheric pressure. An electron beam with amplitude of ~ 170 A with duration at FWHM ~0.3 ns has been obtained. Based on beam temporal characteristics and discharge spatial characteristics, the critical fields were supposed to be reached at plasma approach to anode. Simultaneously, the sharp high-energy pulse of e-beam current is generated. Of critical importance is cathode type and plasma protrusions occurred on the cathode. It is shown that in order to get maximum e-beam in gas diode, the discharge in gas diode should be volume.

Properties of plasma produced in volume nanosecond high-pressure discharge and its formation conditions under elevated pressure in air, nitrogen, krypton, argon, neon and gas mixtures Ar-N2, Ar-Xe, CO2-N2-He in the gap with the cathode having small curvature radius have been investigated. Time-amplitude characteristics and radiation spectra of plasma in different gases in the range of 230-600 nm were defined. Lasing in the gas mixture Ar-Xe at active length of 1.5 cm has been achieved by excitation through volume nanosecond high-pressure discharge. Comparison of spectral radiation in nitrogen, krypton, argon, and neon under pumping of mentioned gases by volume discharge in non-uniform electric field, by nanosecond e-beam, and by volume pulsed discharge in the uniform electric field with high initial voltage was made. Lasing has also been obtained in the gas mixture CO2-N2-He under pumping by e-beam initiated discharge. The electron beam was formed in a gas diode filled the same gas mixture.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.