Optical characteristics of a low-density electric discharge bromine vapor plasma in the UV-VUV spectral region

The emission characteristics of a glow discharge in bromine vapor have been investigated in the spectral region 130–350 nm. The current-voltage characteristics and the emission spectra of the glow discharge with an interelectrode gap of 10 cm and a discharge tube 14 mm in inner diameter have been studied. The emission characteristics have been optimized as functions of the bromine vapor pressure and the power deposited into the plasma. It has been shown that, at a low pressure of the bromine vapor, the emission spectrum of the lamp is determined by the spectral lines of atomic bromine in the range 158–164 nm, which are analogous to the known lines (such as those at 206.2 nm) of atomic iodine in an iodine-containing glow discharge plasma. As the pressure of the bromine vapor increases above 100 Pa, the intensity of these emission lines of the bromine atom decreases and the lamp spectrum is formed by bromine molecular bands in the form of a continuum with sharp boundaries (λ = 165–300 nm).     

Emission characteristics of a high-power glow discharge plasma in a mixture of inert gases with bromine and iodine vapor

The results of an investigation of the UV radiation from the plasma of a dc glow discharge in mixtures of inert gases with bromine and iodine molecules are presented. The current-voltage and spectral characteristics of a longitudinal glow discharge with a power of 10–250 W are studied. The power and the efficiency of the total UV radiation of the plasma, as well as the power of radiation at the spectral line of the iodine atom at 206.2 nm, are optimized as functions of the power deposited into the plasma and the composition of the gas mixture. In active media based on Kr-Br₂ mixtures, the molecular emission of the plasma was represented by bands at 207 (KrBr(B-X)) and 289 nm (Br ₂ ^* ), while, in He-Xe-I₂ mixtures, it was represented by bands at 253 (XeI(B-X)) and 342 nm (I₂).     

Emission characteristics of a glow discharge in a mixture of heavy inert gases with iodine vapor

The results of a systematic investigation of the emission characteristics of a low-pressure UV excimer-halogen lamp pumped by a longitudinal dc glow discharge are presented. The discharge was initiated in mixtures of heavy inert gases with iodine vapor at a total pressure of 100–2000 Pa and a power deposited into the plasma of 10–100 W. Current-voltage characteristics of the glow discharge and emission spectra of the plasma in the region of 190–360 nm are studied. The radiation intensity at the resonance line of the iodine atom (206.2 nm) and the intensity at the peaks of the XeI(B-X) (253 nm) and I₂(B-X) (342 nm) emission bands are analyzed as functions of the pressure and partial composition of the mixtures of Ar, Kr, and Xe with iodine vapor, as well as the electric power of the glow discharge. The most efficient gas mixtures are determined for an electric-discharge UV iodine vapor lamp with continuous-wave emission and a long service life before a change of the mixture is required.     

Emission characteristics of a barrier discharge in an argon-freon-water vapor mixture in the UV-VUV spectral range

Optical characteristics of an ArCl*-OH* lamp excited by a nanosecond barrier discharge are studied. This discharge is a source of the ArCl (B → X), (D’ → A’), and OH(A → X) molecular band emission with peaks at 175, 258, and 309 nm, respectively. The intensity of the barrier discharge plasma radiation is optimized as a function of the CCl₄ vapor partial pressure at p(Ar) = 24 kPa and p(H₂O) = 10–20 Pa.     

Emission characteristics of a gas-discharge plasma of water vapor in the vacuum UV region of the spectrum

We present the results of a study of emission from a low-density water vapor plasma in the vacuum ultraviolet (VUV) region of the spectrum. The plasma was formed in a longitudinal glow discharge. We have studied the spectral characteristics of the plasma and also the dependences of the relative energy characteristics of the hydroxyl (OH) emission band on the discharge current and the helium partial pressure in a He-H₂O mixture in the spectral range 130–190 nm. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 6, pp. 831–833, November–December, 2006.     

Emission characteristics of a glow discharge plasma based on a mixture of helium with chlorine molecules

We present the results of a study of the emission characteristics of a longitudinal glow discharge based on a mixture of helium and chlorine. Study of the emission characteristics of the discharge showed that it emits most efficiently in the bands of the chlorine molecule with maxima at 200 nm and 258 nm in an He-Cl₂ mixture (P = 0.2–0.3 kPa). We present the optimization of the average emission power of a UV emitter as a function of the glow discharge parameters, the pressure, and the composition of the working gas mixture. Based on solution of the Boltzmann equation for the electron energy distribution function in a discharge based on the optimal mixture (according to experimental data), we calculated the power losses per unit pressure going toward elementary processes, the electron transport characteristics, the ionization and attachment coefficients as a function of the parameter E/P. The calculated parameters of the plasma for the UV emitter allowed us to provide a basis for the qualitative pattern of physicochemical processes in the studied plasma. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 1, pp. 121–124, January–February, 2008.     

Emission and absorption studies of copper vapor ejected from a pulsed hollow cathode discharge

The time evolution of the Cu vapor cloud formed outside a hollow cathode during pulsed operation was probed using spectral absorption and emission methods. The absorption studies were carried out using a second Cu discharge as a light source, and the emission from the vapor cloud was excited with an auxiliary electrode placed at right angles to the cathode axis. The experimental results indicate the formation of an extended region of Cu vapor ejected from the hollow cathode, of density comparable to that produced inside the cathode cavity and with persistence times up to 1 ms using 200-μsec discharge pulses. The experiments provide additional insight into the mechanisms governing the action of a pulsed, hollow cathode discharge.     

Pulsed-periodic UV emitter tunable near the main absorption maximum of a DNA molecule

The spectral characteristics of a pulsed-periodic lamp with three dielectric barriers are presented for the range 220–250 nm. As the active media of the lamp, krypton (Kr)-sulfur hexafluoride (SF₆) and krypton-carbon tetrachloride (CCl₄) mixtures are tested. The use of Kr-SF₆ and Kr-CCl₄ binary mixtures in two noncommunicating volumes is shown to be more effective than the use of a Kr-SF₆-CCl₄ ternary mixture with the same amount of Kr, SF₆, and CCl₄ constituents. The emission spectrum of the lamp near the maxima of the KrF(X-B) 248-nm and KrCl(X-B) 222-nm bands can be controlled by varying the partial pressures of halogen carriers and krypton.     

Emission characteristics of the cathode region of nanosecond discharge in atmospheric-pressure air

The emission spectra of a nanosecond discharge between copper electrodes in atmospheric-pressure air are studied at a high discharge gap overvoltage. The discharge was ignited between two cylindrical electrodes with a small radius of curvature of the working surface. Oscillograms of radiation pulses of spectral lines of copper atoms are also studied. The electron temperature averaged over the pulse is determined from the intensity distributions of the spectral lines of copper atoms.     

氦氩射频容性放电发射光谱分析

光抽运亚稳态稀有气体激光器利用放电等离子体作为激光的增益介质.为掌握容性射频放电的放电参数对等离子体各项参数的影响的基本规律,利用等离子体发射光谱法研究了氦氩混合气体在不同装置、不同Ar组分、不同气压和不同射频注入功率下的等离子体参数.利用残留水蒸气产生的OH自由基A~2Σ~+→X~2Π的转动光谱分析获得气体温度;利用电子态光谱的玻尔兹曼做图法获得电子激发温度,利用Ar原子696.5 nm谱线的斯塔克展宽获得电子密度.结果表明:气体温度随气压增加略微上升,在一个大气压下改变组分和放电功率,气体温度变化不大;电子激发温度随总气压的下降而上升,且随着Ar组分的增加而略微下降;目前放电条件下的电子密度均在10~(15)cm~(-3)量级;长时间放电监测表明,残留的水蒸气会导致电子温度的下降,从而降低Ar亚稳态的产率.     

Determination of plasma characteristics in the plasma of a pulsed discharge propagating over a water surface using spectral methods

The results of spectral investigations of the electron density and excitation temperature in the plasma of a pulsed discharge propagating over a liquid surface are presented.     

Formation of a high-current discharge plasma in metal vapor

A method of converting the energy of a capacitive store into the energy of a high-current gas discharge in aluminum vapor is investigated. The spatial and temporal characteristics of the gas-discharge plasma are studied. The electron temperature, density of charged particles, and conductivity of the plasma are determined. Zh. Tekh. Fiz. 69, 134–137 (November 1999)     

Emission characteristics and electron kinetic coefficients of the plasma of a transverse volume discharge initiated in a mixture of heavy inert gases with chlorine molecules

The results of studying the radiation due to argon, krypton, and xenon monochloride bands, as well as to the bands of chlorine molecules, from the plasma of a transverse Ar-Kr-Xe-Cl₂ volume discharge are reported. The working mixture of a pulse radiation source is optimized with regard to its pressure and elemental composition and parameters of an excitation system. By numerically solving the Boltzmann kinetic equation for the electron energy distribution function, the transport characteristics of plasma electrons and discharge power specific losses are found for different values of the reduced electric field strength. The plasma parameters are simulated for the quaternary mixture, which is most appropriate for a multiwave UV-VUV source. Qualitative analysis is conducted for the most important electron processes in the multicomponent plasma that govern the joint formation of argon, krypton, and xenon monochlorides in the transverse discharge.     

Emission characteristics of a pulsed discharge in xenon

Emission characteristics of a high-current pulsed discharge in xenon are studied experimentally. The study is aimed at developing a source of spontaneous UV radiation (with λ ≤ 250 nm) for controlling highvoltage crystalline diamond switches.     

Emission characteristics of pulse-periodic barrier-discharge plasma in a mixture of krypton with argon and liquid freon vapor

Radiation of a nanosecond barrier discharge in a mixture of krypton, argon, and carbon-tetrachloride vapor is studied in the spectral range of 150–300 nm. The plasma radiation spectra and the dependences of the intensities of the 258 nm Cl₂(D′ → A′), 222 nm KrCl(B → X), and 175 nm ArCl(B → X) bands on the partial pressure of liquid freon vapor, argon, and krypton, as well as on the discharge excitation conditions, are studied. The optimal compositions of gas mixtures for creating a broadband UV-VUV emitter based on the band system of argon chloride, krypton chloride, and chlorine molecule are determined.     

Influence of water vapor pressure fluctuations on the spectral density of millimeter wave amplitude scintillations in an absorption region

Results are presented of scintillation spectra, measured at 54.5GHz on a 4.1 km line of sight path, when the variance of the water vapour pressure fluctuations (_e ²) is very much greater than the variance of the temperature fluctuations (_T ²). The effect of _e ² under these conditions is established both through the experimental results and the theoretical considerations which are also presented.