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Sample records for glow discharge optical

  1. New developments in glow discharge optical emission and mass spectrometry

    International Nuclear Information System (INIS)

    Hoffmann, Volker; Dorka, Roland; Wilken, Ludger; Wetzig, Klaus

    2000-01-01

    This paper describes new developments in flow discharge optical emission (GD-OES) and mass spectrometry (GD-MS) at IFW and presents corresponding new applications (analysis of microelectronic multi-layer system by radio frequency glow discharge optical emission spectrometry (RF-GD-OES) and analysis of pure iron by a new Grimm-type GD-MS source)

  2. Glow discharge lamp: a light source for optical emission spectroscopy

    International Nuclear Information System (INIS)

    Vishwanathan, K.S.; Srinivasan, V.; Nalini, S.; Mahalingam, T.R.

    1990-01-01

    A glow discharge lamp based on a modified version of the Grimm design has been fabricated. Its utility as a radiation source for optical emmission spectrography by standardising a method for the analysis of low alloy steels using a set of certified standards from DMRL, Hyderabad, has been demonstrated. A model has been proposed where the sputtering rates of different metals have been correlated with their heats of sublimation, metallic radii and densities. Sputtering rates of ten different metals obtained from literature have been used to test this model, and the correlation appears to be excellent. (author). 19 re fs., 13 figs., 2 tabs

  3. Glow discharge optical emission spectroscopy for accurate and well resolved analysis of coatings and thin films

    KAUST Repository

    Wilke, Marcus; Teichert, Gerd; Gemma, Ryota; Pundt, Astrid; Kirchheim, Reiner; Romanus, Henry; Schaaf, Peter

    2011-01-01

    overview on new developments in instrument design for accurate and well resolved thin film analyses is presented. The article focuses on the analytical capabilities of glow discharge optical emission spectrometry in the analysis of metallic coatings

  4. Glow discharging device

    International Nuclear Information System (INIS)

    Maeno, Katsuki; Kawasaki, Kozo; Hiratsuka, Hajime; Kawashima, Shuichi.

    1989-01-01

    In a thermonuclear device, etc. impurities adsorbed to inner walls of a vacuum vessel by glow discharge are released to clean the vacuum vessel for preventing intrusion of the impurities into plasmas. The object of the present invention is to minimize the capacity of a power source equipment for the glow discharge device to the least extent. That is, a stabilization resistance is connected in series between each of a plurality of anodes which are inserted and arranged at the inside of a vacuum vessel as a cathode and a power source respectively. The resistance value R is selected so as to satisfy the relation: R < (Vi - Vm)/Ii, in which Vi: glow discharge starting voltage, Vm: glow discharge keeping voltage, Ii: glow discharge starting current. Accordingly, if a voltage is applied from a power source to a plurality of anodes, scattering of electric discharge between the anodes can be suppressed and the effect of voltage drop during discharge by the stabilization resistance can be eliminated. As a result, it is possible to provide an economically advantageous glow discharge device with the capacity for the power source facility being to the least extent. (K.M.)

  5. The impact of molecular emission in compositional depth profiling using Glow Discharge-Optical Emission Spectroscopy

    International Nuclear Information System (INIS)

    Bengtson, Arne

    2008-01-01

    The scope of this paper is to investigate and discuss how molecular emission can affect elemental analysis in glow discharge optical emission (GD-OES), particularly in compositional depth profiling (CDP) applications. Older work on molecular emission in glow discharges is briefly reviewed, and the nature of molecular emission spectra described. Work on the influence of hydrogen in the plasma, in particular elevated background due to a continuum spectrum, is discussed. More recent work from sputtering of polymers and other materials with a large content of light elements in a Grimm type source is reviewed, where substantial emission has been observed from several light diatomic molecules (CO, CH, OH, NH, C 2 ). It is discussed how the elevated backgrounds from such molecular emission can lead to significant analytical errors in the form of 'false' depth profile signals of several atomic analytical lines. Results from a recent investigation of molecular emission spectra from mixed gases in a Grimm type glow discharge are presented. An important observation is that dissociation and subsequent recombination processes occur, leading to formation of molecular species not present in the original plasma gas. Experimental work on depth profiling of a polymer coating and a thin silicate film, using a spectrometer equipped with channels for molecular emission lines, is presented. The results confirm that molecular emission gives rise to apparent depth profiles of elements not present in the sample. The possibilities to make adequate corrections for such molecular emission in CDP of organic coatings and very thin films are discussed

  6. Glow discharge optical emission spectroscopy for accurate and well resolved analysis of coatings and thin films

    KAUST Repository

    Wilke, Marcus

    2011-12-01

    In the last years, glow discharge optical emission spectrometry (GDOES) gained more and more acceptance in the analysis of functional coatings. GDOES thereby represents an interesting alternative to common depth profiling techniques like AES and SIMS, based on its unique combination of high erosion rates and erosion depths, sensitivity, analysis of nonconductive layers and easy quantification even for light elements such as C, N, O and H. Starting with the fundamentals of GDOES, a short overview on new developments in instrument design for accurate and well resolved thin film analyses is presented. The article focuses on the analytical capabilities of glow discharge optical emission spectrometry in the analysis of metallic coatings and thin films. Results illustrating the high depth resolution, confirmation of stoichiometry, the detection of light elements in coatings as well as contamination on the surface or interfaces will be demonstrated by measurements of: a multilayer system Cr/Ti on silicon, interface contamination on silicon during deposition of aluminum, Al2O3-nanoparticle containing conversion coatings on zinc for corrosion resistance, Ti3SiC2 MAX-phase coatings by pulsed laser deposition and hydrogen detection in a V/Fe multilayer system. The selected examples illustrate that GDOES can be successfully adopted as an analytical tool in the development of new materials and coatings. A discussion of the results as well as of the limitations of GDOES is presented. © 2011 Elsevier B.V.

  7. The impact of molecular emission in compositional depth profiling using Glow Discharge-Optical Emission Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bengtson, Arne [Corrosion and Metals Research Institute, Dr. Kristinas vaeg 48, Stockholm (Sweden)], E-mail: arne.bengtson@kimab.com

    2008-09-15

    The scope of this paper is to investigate and discuss how molecular emission can affect elemental analysis in glow discharge optical emission (GD-OES), particularly in compositional depth profiling (CDP) applications. Older work on molecular emission in glow discharges is briefly reviewed, and the nature of molecular emission spectra described. Work on the influence of hydrogen in the plasma, in particular elevated background due to a continuum spectrum, is discussed. More recent work from sputtering of polymers and other materials with a large content of light elements in a Grimm type source is reviewed, where substantial emission has been observed from several light diatomic molecules (CO, CH, OH, NH, C{sub 2}). It is discussed how the elevated backgrounds from such molecular emission can lead to significant analytical errors in the form of 'false' depth profile signals of several atomic analytical lines. Results from a recent investigation of molecular emission spectra from mixed gases in a Grimm type glow discharge are presented. An important observation is that dissociation and subsequent recombination processes occur, leading to formation of molecular species not present in the original plasma gas. Experimental work on depth profiling of a polymer coating and a thin silicate film, using a spectrometer equipped with channels for molecular emission lines, is presented. The results confirm that molecular emission gives rise to apparent depth profiles of elements not present in the sample. The possibilities to make adequate corrections for such molecular emission in CDP of organic coatings and very thin films are discussed.

  8. In-situ reactive of x-ray optics by glow discharge

    International Nuclear Information System (INIS)

    Johnson, E.D.; Garrett, R.F.

    1987-01-01

    We have developed a method of in-situ reactive glow discharge cleaning of x-ray optical surfaces which is capable of complete removal of carbon contamination. Our work is the first to successfully clean an entire optical system in-situ and characterize its performance at short wavelengths (as low as 10 /angstrom/). The apparatus required is quite simple and can easily be fitted to most existing UHV (ultra high vacuum) mirror boxes of monochromators. The advantages of this technique over previously available methods include dramatic improvements in instrument performance and reductions in down time since the whole process typically takes a few days. This paper will briefly describe our results and detail the experimental considerations for application of the technique on different monochromator geometries. Possible improvements and extensions of the technique are also discussed

  9. Glow discharge in singlet oxygen

    International Nuclear Information System (INIS)

    Vagin, N.P.; Ionin, A.A.; Klimachev, Yu.M.; Sinitsyn, D.V.; Yuryshev, N.N.; Kochetov, I.V.; Napartovich, A.P.

    2003-01-01

    Currently, there is no experimental data on the plasma balance in gas mixtures with a high content of singlet delta oxygen O 2 ( 1 Δ g ). These data can be obtained by studying the parameters of an electric discharge in singlet oxygen produced by a chemical generator. The O 2 ( 1 Δ g ) molecules significantly change the kinetics of electrons and negative ions in plasma. Hence, the discharge conditions at low and high O 2 ( 1 Δ g ) concentrations are very different. Here, the parameters of the positive column of a glow discharge in a gas flow from a chemical singlet-oxygen generator are studied. It is experimentally shown that, at an O 2 ( 1 Δ g ) concentration of 50% and at pressures of 1.5 and 2 torr, the electric field required to sustain the discharge is considerably lower than in the case when all of the oxygen molecules are in the ground state. A theoretical model of the glow discharge is proposed whose predictions are in good agreement with the experimental data

  10. A study of internal oxidation in carburized steels by glow discharge optical emission spectroscopy and scanning electron microscopy

    CERN Document Server

    An, X; Rainforth, W M; Chen, L

    2003-01-01

    The internal oxidation of Cr-Mn carburizing steel was studied. Internal oxidation was induced using a commercial carburizing process. Sputter erosion coupled with glow discharge optical emission spectroscopy (GDOES) was used to determine the depth profile elemental distribution within the internal oxidation layer (<10 mu m). In addition, scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS) studies were carried out on selected sputter eroded surfaces. Oxide type was identified primarily by transmission electron microscopy (TEM). The carburized surface was found to consist of a continuous oxide layer, followed by a complex internal oxidation layer, where Cr and Mn oxides were found to populate grain boundaries in a globular form in the near surface region. At greater depths (5-10 mu m), Si oxides formed as a grain boundary network. The internal oxides (mainly complex oxides) grew quickly during the initial stages of the carburizing process (2 h, 800 deg. C+3 h, 930 deg. C). G...

  11. dc glow-discharge cleaning for accelerator

    International Nuclear Information System (INIS)

    Chou, T.S.; Hseuh, H.C.

    1982-01-01

    Average pressure of 1 x 10 -11 torr and vacuum stability are necessary for the successful operation of the proton storage rings such as ISABELLE. Vacuum degassing at high temperature and in situ bake-out will reduce the thermoout-gassing rate of the beam tubes to approx. 10 -13 Tl/cm 2 sec, therefore achieving the required static pressure. The vacuum instability caused by beam-induced ion desorption can be solved by dc glow discharge cleaning. With evidence from this study, the present understanding of glow discharge in a cylindrically symmetric geometry is reviewed. Argon and argon/oxygen mixture serve as plasmas in the glow. The role of oxygen in cleaning the beam tubes during the glow discharge is demonstrated experimentally. Glow discharge cleaning with and without bake-out is also studied

  12. Microstructural and optical properties of A-Si: H deposited by DC plasma glow discharge of electrode polarity

    International Nuclear Information System (INIS)

    Salam, R.; Danker, A.R.

    1993-01-01

    A method for deducing the density of valence electrons and the average atomic separation of Si atoms in a-Si:H are presented. Refractive index and optical absorption experimental data on a variety of dc glow discharge deposited a-Si:H samples are utilized to deduce the two parameters. The density of valence electrons depict values in the range (1.47-6.15)x10 22 cm -3 while the average atomic spacing varies within 3.13-4.61 A. The existence of microvoids and regions of rich silicon-hydride phase are proposed to account for this. Comparisons of the electrical conductivity, optical parameters and vibrational modes are done for cathode and anode deposited a-Si:H samples. Conductivity for both types of samples are the same at around 1.3x10 -9 (Ωcm) -1 , but significant differences are observed in the values of the refractive index n and the optical gap Eg of the cathode (4.06, 1.95 eV) and anode (3.13, 2.34 eV) samples. Observations on the infrared spectrum of the two a-Si:H samples suggests that the anode sample contain appreciable amount and a higher proportion of oxygen, as identified by the 2080cm -1 shift of the Si-H stretching mode, while a strong Si-H 3 symmetric deformation mode is proposed to occur in the cathode sample

  13. Study of atmospheric air AC glow discharge using optical emission spectroscopy and near infrared diode laser cavity ringdown spectroscopy

    Science.gov (United States)

    Srivastava, Nimisha; Wang, Chuji; Dibble, Theodore S.

    2008-11-01

    AC glow discharges were generated in atmospheric pressure by applying high voltage AC in the range of 3500-15000 V to a pair of stainless steel electrodes separated by an air gap. The discharges were characterized by optical emission spectroscopy (OES) and continuous wave cavity ringdown spectroscopy (cw-CRDS). The electronic (Tex), vibrational (Tv), and rotational (Tr) temperatures were measured. Spectral stimulations of the emission spectra of several vibronic bands of the 2^nd positive system of N2, the 1^st negative system of N2^+, the (0,1,2,3-0) bands of NO (A-X), and the (0-0) band of OH (A-X), which were obtained under various plasma operating conditions, show that Tr, Tv, and Tex are in the ranges of 2000 - 3800, 3500 - 5000, and 6000 - 10500^ K, respectively. Emission spectra show that OH concentration increases while NO concentration decreases with an increase of electrode spacing. The absorption spectra of H2O and OH overtone in the near infrared (NIR) were measured by the cw-CRDS with a telecommunications diode laser at wavelength near 1515 nm.

  14. Radio-frequency glow discharge spectrometry: A critical review

    International Nuclear Information System (INIS)

    Winchester, Michael R.; Payling, Richard

    2004-01-01

    This paper presents a critical review of analytical radio frequency glow discharge spectrometry (rf-GDS). The historical foundations of rf-GDS are described, and current knowledge of the fundamental physics of analytical rf glow discharges is discussed. Additionally, instrumentation, methodologies, and applications of rf glow discharge optical emission spectrometry (rf-GDOES) and mass spectrometry (rf-GDMS) are reviewed. Although other rf-GDS techniques have appeared [e.g. rf glow discharge atomic absorption spectrophotometry (rf-GDAAS)], the emphasis is placed upon rf-GDOES and rf-GDMS, because they have received by far the most interest from analytical chemical metrologists. This review also provides explanations of some developments that are needed for further progress in the field of analytical rf-GDS

  15. A study of internal oxidation in carburized steels by glow discharge optical emission spectroscopy and scanning electron microscopy

    International Nuclear Information System (INIS)

    An, X; Cawley, J.; Rainforth, W.M.; Chen, L.

    2003-01-01

    The internal oxidation of Cr-Mn carburizing steel was studied. Internal oxidation was induced using a commercial carburizing process. Sputter erosion coupled with glow discharge optical emission spectroscopy (GDOES) was used to determine the depth profile elemental distribution within the internal oxidation layer (<10 μm). In addition, scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS) studies were carried out on selected sputter eroded surfaces. Oxide type was identified primarily by transmission electron microscopy (TEM). The carburized surface was found to consist of a continuous oxide layer, followed by a complex internal oxidation layer, where Cr and Mn oxides were found to populate grain boundaries in a globular form in the near surface region. At greater depths (5-10 μm), Si oxides formed as a grain boundary network. The internal oxides (mainly complex oxides) grew quickly during the initial stages of the carburizing process (2 h, 800 deg. C+3 h, 930 deg. C). GDOES proved to be an excellent tool for the quantification of oxidation and element distribution as a function of depth, particularly when combined with SEM and TEM to identify oxide type and morphology

  16. Nanometric resolution in glow discharge optical emission spectroscopy and Rutherford backscattering spectrometry depth profiling of metal (Cr, Al) nitride multilayers

    International Nuclear Information System (INIS)

    Escobar Galindo, R.; Gago, R.; Fornies, E.; Munoz-Martin, A.; Climent Font, A.; Albella, J.M.

    2006-01-01

    In this work, we address the capability of glow discharge optical emission spectroscopy (GDOES) for fast and accurate depth profiling of multilayer nitride coatings down to the nanometer range. This is shown by resolving the particular case of CrN/AlN structures with individual thickness ranging from hundreds to few nanometers. In order to discriminate and identify artefacts in the GDOES depth profile due to the sputtering process, the layered structures were verified by Rutherford backscattering spectrometry (RBS) and scanning electron microscopy (SEM). The interfaces in the GDOES profiles for CrN/AlN structures are sharper than the ones measured for similar metal multilayers due to the lower sputtering rate of the nitrides. However, as a consequence of the crater shape, there is a linear degradation of the depth resolution with depth (approximately 40 nm/μm), saturating at a value of approximately half the thickness of the thinner layer. This limit is imposed by the simultaneous sputtering of consecutive layers. The ultimate GDOES depth resolution at the near surface region was estimated to be of 4-6 nm

  17. Detection of negative ions in glow discharge mass spectrometry for analysis of solid specimens

    DEFF Research Database (Denmark)

    Canulescu, Stela; Molchan, Igor S.; Tauziede, C.

    2010-01-01

    A new method is presented for elemental and molecular analysis of halogen-containing samples by glow discharge time-of-flight mass spectrometry, consisting of detection of negative ions from a pulsed RF glow discharge in argon. Analyte signals are mainly extracted from the afterglow regime...... be used to study the distribution of a tantalum fluoride layer within the anodized tantala layer. Further, comparison is made with data obtained using glow-discharge optical emission spectroscopy, where elemental fluorine can only be detected using a neon plasma. The ionization mechanisms responsible...... for the formation of negative ions in glow discharge time-of-flight mass spectrometry are briefly discussed....

  18. Plasma Beam Interaction with Negative glow discharge

    International Nuclear Information System (INIS)

    El-Tayeb, H.A.; El-Gamal, H.A.

    2000-01-01

    A miniature coaxial gun has been used to study the effect of the energy spectrum of the ejected plasma on the interaction with negative glow region in a normal glow discharge. The peak discharge current flow between the coaxial electrodes was 5.25 K A as a single pulse with pulse duration of 60 MUs. Investigations are carried out with argon gas at pressure 0.4 Torr. The sheath thickness of the ejected plasma from the coaxial discharge was 6 cm with different densities and energies. The spectrum of electron energy varies between 6 eV and 1 eV, while the electron density varies between 5 x 10 12 cm -3 and 4x10 13 cm -3 . The peak velocity of the ejected plasma was 0. 8 x 10 5 cm sec -1 in the neutral argon atoms. Argon negative glow region used as base plasma has an electron temperature of 2.2 eV and electron density of 6.2 x10 7 cm -3 . It had been found that the velocity of the ejected plasma decreased when it moves in the negative glow region and its mean electron temperature decreased. The results are compared with the theory of beam interaction with cold plasma

  19. Propagation of ionizing waves in glow discharge

    International Nuclear Information System (INIS)

    Suzuki, T.

    1977-01-01

    Ionizing waves were produced along the positive column of a glow discharge in air by applying an impulse voltage to an electrode at one end of the column. Five photomultipliers and three current-sensing coils were used to observe how the waves were affected by the rise time and the magnitude of the applied impulses and by the electron density in the positive column of the glow discharge. It is shown that the speed of the ionizing waves increases with the slope of the applied impulses and with the preexisting electron density. The electron density is augmented about 100--200 times due to the buildup of ionization at the front of the waves. The theory was developed to explain the property of ionizing waves

  20. Is the negative glow plasma of a direct current glow discharge negatively charged?

    International Nuclear Information System (INIS)

    Bogdanov, E. A.; Saifutdinov, A. I.; Demidov, V. I.; Kudryavtsev, A. A.

    2015-01-01

    A classic problem in gas discharge physics is discussed: what is the sign of charge density in the negative glow region of a glow discharge? It is shown that traditional interpretations in text-books on gas discharge physics that states a negative charge of the negative glow plasma are based on analogies with a simple one-dimensional model of discharge. Because the real glow discharges with a positive column are always two-dimensional, the transversal (radial) term in divergence with the electric field can provide a non-monotonic axial profile of charge density in the plasma, while maintaining a positive sign. The numerical calculation of glow discharge is presented, showing a positive space charge in the negative glow under conditions, where a one-dimensional model of the discharge would predict a negative space charge

  1. Glow discharge based device for solving mazes

    Energy Technology Data Exchange (ETDEWEB)

    Dubinov, Alexander E., E-mail: dubinov-ae@yandex.ru; Mironenko, Maxim S.; Selemir, Victor D. [Russian Federal Nuclear Center − All-Russian Scientific and Research Institute of Experimental Physics (RFNC-VNIIEF), Sarov, Nizhni Novgorod region 607188 (Russian Federation); Sarov Institute of Physics and Technology (SarFTI) of National Research Nuclear University “MEPhI,” Sarov, Nizhni Novgorod region 607188 (Russian Federation); Maksimov, Artem N.; Pylayev, Nikolay A. [Russian Federal Nuclear Center − All-Russian Scientific and Research Institute of Experimental Physics (RFNC-VNIIEF), Sarov, Nizhni Novgorod region 607188 (Russian Federation)

    2014-09-15

    A glow discharge based device for solving mazes has been designed and tested. The device consists of a gas discharge chamber and maze-transformer of radial-azimuth type. It allows changing of the maze pattern in a short period of time (within several minutes). The device has been tested with low pressure air. Once switched on, a glow discharge has been shown to find the shortest way through the maze from the very first attempt, even if there is a section with potential barrier for electrons on the way. It has been found that ionization waves (striations) can be excited in the maze along the length of the plasma channel. The dependancy of discharge voltage on the length of the optimal path through the maze has been measured. A reduction in discharge voltage with one or two potential barriers present has been found and explained. The dependency of the magnitude of discharge ignition voltage on the length of the optimal path through the maze has been measured. The reduction of the ignition voltage with the presence of one or two potential barriers has been observed and explained.

  2. Glow discharge depth analysis of metallic elements in steels

    International Nuclear Information System (INIS)

    Berneron, R.

    The glow discharge lamp designed by Grimm gives new possibilities in the optical spectrometry. The plasma produced is a cool emissive source and its advantages are the following: low spectral background, no reabsorption, linear calibration, very stable emission, very high yield. The sputtering produced by ionic bombardment of the sample enables the depth repartition of several elements to be made in the same run [fr

  3. Liquid sampling-atmospheric pressure glow discharge optical emission spectroscopy detection of laser ablation produced particles: A feasibility study

    International Nuclear Information System (INIS)

    Quarles, C. Derrick; Gonzalez, Jhanis; Choi, Inhee; Ruiz, Javier; Mao, Xianglei; Marcus, R. Kenneth; Russo, Richard E.

    2012-01-01

    The use of a liquid sampling-atmospheric pressure glow discharge (LS-APGD) microplasma source as an alternative to conventional inductively coupled plasma (ICP) detection of laser ablation (LA) produced particles using a Nd:YAG laser at 1064 nm is demonstrated. This configuration utilizes a 180° geometry, which is different from the 40° geometry that was used to ionize ablated particles followed by mass spectrometric detection. The use of a hollow counter electrode (nickel, 0.3 cm o.d., 0.1 cm i.d.) was implemented to introduce ablated particles directly into the APGD plasma with helium as a carrier gas. The LS-APGD source was optimized using ablated copper as the test sample (helium carrier gas flow rate (0.30 L min −1 He), discharge current (60 mA), laser power (44 mJ), and solution electrode sheath gas (0.2 L min −1 He) and solution flow rates (10 μL min −1 5% HNO 3 )). Standard brass samples having known Zn/Cu percentages were ablated and analyzed using the LS-APGD source. As a comparison, the established technique of laser-induced breakdown spectroscopy (LIBS) was used to analyze the same set of brass standards under similar ablation conditions to the LS-AGPD measurements, yielding comparable results. The Zn/Cu ratio results for the LS-APGD and LIBS measurements showed good similarity to previous measurements using ICP-MS detection. The performance of the LS-APGD–OES microplasma, comparable to well established methods, with lower capital and operational overhead expenses, suggests a great deal of promise as an analytical excitation source. - Highlights: ► Particles formed by laser ablation are readily introduced to the LS-APGD microplasma. ► The low power microplasma has sufficient energy to vaporize laser produced particles. ► Qualitative analysis of brass alloys is performed using a simple OES ratio method. ► The qualitative performance of the LS-APGD microplasma is on-par with LIBS analysis.

  4. Electron beam generation in high voltage glow discharges

    International Nuclear Information System (INIS)

    Rocca, J.J.; Szapiro, B.; Murray, C.

    1989-01-01

    The generation of intense CW and pulsed electron beams in glow discharges in reviewed. Glow discharge electron guns operate at a pressure of the order of 1 Torr and often have an advantage in applications that require a broad area electron beam in a gaseous atmosphere, such as laser excitation and some aspects of materials processing. Aspects of electron gun design are covered. Diagnostics of the high voltage glow discharges including the electric field distribution mapped by Doppler free laser spectroscopy, and plasma density and electron temperature measurements of the electron yield of different cathode materials under glow discharge conditions are presented

  5. Time-resolved measurement of emission profiles in pulsed radiofrequency glow discharge optical emission spectroscopy: Investigation of the pre-peak

    International Nuclear Information System (INIS)

    Alberts, D.; Horvath, P.; Nelis, Th.; Pereiro, R.; Bordel, N.; Michler, J.; Sanz-Medel, A.

    2010-01-01

    Radiofrequency glow discharge coupled to optical emission spectroscopy has been used in pulsed mode in order to perform a detailed study of the measured temporal emission profiles for a wide range of copper transitions. Special attention has been paid to the early emission peak (or so-called pre-peak), observed at the beginning of the emission pulse profile. The effects of the important pulse parameters such as frequency, duty cycle, pulse width and power-off time, have been studied upon the Cu pulse emission profiles. The influence of discharge parameters, such as pressure and power, was studied as well. Results have shown that the intensity observed in the pre-peak can be 10 times as large as the plateau value for resonant lines and up to 5 times in case of transitions to the metastable levels. Increasing pressure or power increased the pre-peak intensity while its appearance in time changed. The pre-peak decreased when the discharge off-time was shorter than 100 μs. According to such results, the presence of the pre-peak could be probably due to the lack of self-absorption during the first 50 μs, and not to the ignition of the plasma. Under the selected operation conditions, the use of the pre-peak emission as analytical signals increases the linearity of calibration curves for resonant lines subjected to self-absorption at high concentrations.

  6. Time-resolved measurement of emission profiles in pulsed radiofrequency glow discharge optical emission spectroscopy: Investigation of the pre-peak

    Energy Technology Data Exchange (ETDEWEB)

    Alberts, D. [Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julian Claveria 8, 33006 Oviedo (Spain); Horvath, P. [Swiss Federal Laboratories for Materials Testing and Research (EMPA), Feuerwerkerstrasse 39, 3602 Thun (Switzerland); Nelis, Th. [LAPLACE, Universite Paul Sabatier, 118 rte de Narbonne, Bat3R2, 31062 Toulouse Cedex (France); CU Jean Francois Champollion, Place de Verdun 81012 Albi Cedex 9 (France); Pereiro, R. [Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julian Claveria 8, 33006 Oviedo (Spain); Bordel, N. [Department of Physics, Faculty of Science, University of Oviedo, Calvo Sotelo, 33007 Oviedo (Spain); Michler, J. [Swiss Federal Laboratories for Materials Testing and Research (EMPA), Feuerwerkerstrasse 39, 3602 Thun (Switzerland); Sanz-Medel, A., E-mail: asm@uniovi.e [Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julian Claveria 8, 33006 Oviedo (Spain)

    2010-07-15

    Radiofrequency glow discharge coupled to optical emission spectroscopy has been used in pulsed mode in order to perform a detailed study of the measured temporal emission profiles for a wide range of copper transitions. Special attention has been paid to the early emission peak (or so-called pre-peak), observed at the beginning of the emission pulse profile. The effects of the important pulse parameters such as frequency, duty cycle, pulse width and power-off time, have been studied upon the Cu pulse emission profiles. The influence of discharge parameters, such as pressure and power, was studied as well. Results have shown that the intensity observed in the pre-peak can be 10 times as large as the plateau value for resonant lines and up to 5 times in case of transitions to the metastable levels. Increasing pressure or power increased the pre-peak intensity while its appearance in time changed. The pre-peak decreased when the discharge off-time was shorter than 100 {mu}s. According to such results, the presence of the pre-peak could be probably due to the lack of self-absorption during the first 50 {mu}s, and not to the ignition of the plasma. Under the selected operation conditions, the use of the pre-peak emission as analytical signals increases the linearity of calibration curves for resonant lines subjected to self-absorption at high concentrations.

  7. Improvement of the detection limits in radio-frequency-powered glow discharge optical emission spectrometry associated with bias-current conduction method; Jiko bias denryu donyuho ni yoru koshuha glow hoden hakko bunseki ni okeru kenshutsu genkai no kaizen

    Energy Technology Data Exchange (ETDEWEB)

    Wagatsuma, K. [Tohoku University, Sendai (Japan). Research Institute for Materials

    1999-01-01

    A d.c. bias current driven by the self-bias voltage which is conducted through the r.f.-powered glow discharge plasma varies the emission characteristics drastically, leading to improvement of the detection power in the optical emission spectrometry. By conducting the bias currents of 20-30 mA, the emission intensities of the atomic resonance lines were 10-20 times larger than those obtained with conventional r.t.- powered plasmas. The detection limits for determination of alloyed elements in the re-based binary alloy samples were estimated to be l.6 x 10{sup -3}% Cr for CrI 425.43nm, 7 x 10{sup -4}% Mn for MnI 403.10nm, 1.9>10{sup -3}% Cu for CuI 327.40nm, 1.1 x 10{sup -3}% Al for AlI 396.16nm, and 6.6 x 10{sup -3}% Ni for NiI 352.45 nm. (author)

  8. Easy to implement diagnostics of a glow dielectric barrier discharge

    International Nuclear Information System (INIS)

    Massines, F.; Segur, P.

    2001-01-01

    It is relatively easier to generate plasma at atmospheric pressure rather than low pressure. In retaliation, due to the short mean free path of different particles, the diagnostics giving microscopic characteristics are more difficult to implement. This, for example, is the case of Langmuir probe or mass spectrometry although solutions have been put forward. Likewise, the strong contribution of the excited state quenching can render optical characterization result interpretation difficult. Nevertheless, there are easy to implement basic diagnostics like optical emission spectroscopy, the ultra rapid photography or the discharge current measurement. A possible approach to get to the microscopic data consists in associating the experimental results with the results of a numerical model. This is the approach undertaken for the study of a glow dielectric barrier discharge (DBD) and is described in the following text in order to illustrate the possibilities of those easy to implement diagnostics supported by the analysis of surfaces having interacted with the plasma

  9. Glow plasma jet - experimental study of a transferred atmospheric pressure glow discharge

    International Nuclear Information System (INIS)

    Guerra-Mutis, Marlon H; U, Carlos V Pelaez; H, Rafael Cabanzo

    2003-01-01

    In this paper we present the experimental study of a glow plasma jet (GPJ) obtained from a transferred atmospheric pressure glow discharge (APGD) operating at 60 Hz. The characterization of the emission spectra for both electrical discharges is presented and the electrical circuit features for APGD generation are discussed. The potentiality of GPJ as a source of active species for depletion of contaminants in liquid hydrocarbon fractions is also established

  10. The measurement and analysis of electric fields in glow discharge plasmas

    International Nuclear Information System (INIS)

    Lawler, J.E.; Doughty, D.A.

    1994-01-01

    Interest in glow discharge plasmas has remained high for many decades because of their widespread application as a source of incoherent and coherent light, in plasma processing materials, in pulsed power devices, and in other technologies. Plasma etching of semiconductors and various plasma deposition process emerged as major applications during the 1980s. The technological significance of plasma processing is described in Plasma Processing of Materials. More fundamental work on glow discharges also advanced greatly during the 1980s. For example, substantial progress was made through the use of laser diagnostics to study glow discharges and as a result of the dramatically increased computing power that became available in the 1980s to model glow discharges. Many of the laser diagnostics are described in Radiative Processes in Discharge Plasmas. Kinetic theory models, in particular, became far more sophisticated and realistic during the 1980s. This article is a review of recent work that used optical diagnostics to study electric fields in glow discharge plasmas. Alternative methods for measuring electric electric fields in plasmas include electron beam deflection and electrostatic probes. Optical techniques have important advantages over these methods: They can be used at higher pressures and discharge current densities than electron beam deflection; and they are noninvasive, unlike electrostatic probes. In addition, optical techniques are usually easier to apply in a highly pure system than either of the alternative methods. 46 refs., 23 figs., 1 tab

  11. Space structure of the glow discharge with free side boundary

    International Nuclear Information System (INIS)

    Yatsenko, N.A.

    1995-01-01

    The main purpose of this work is to reveal physical reasons, which are responsible for the formation of space structure of glow type discharge with free side boundary, both in DC and in RF electric fields. By now extensive experimental material have been accumulated in discharge physics. Also many theoretical models have been proposed for describing separate parts of discharge with the cold electrodes (cathode and anode regions, positive column and transition zones - glow luminescence and Farraday's dark space of DC-discharge, electrode regions and plasma column of RF capacitive discharge). As this takes place, the majority of known works are devoted to some one part of gas discharge - positive column, electrode regions, transition zones and so on. At the same time just now we don't know anything about space structure of free, steady-state gas discharge of glow type, as a whole, especially when the pressure p much-gt 1 Torr

  12. On the distribution of plasma parameters in RF glow discharge

    International Nuclear Information System (INIS)

    Ning Cheng; Liu Zuli; Liu Donghui; Han Caiyuan.

    1993-01-01

    A self-consistent numerical model based on the two-fluid equations for describing the transport of charged particles in the RF glow discharge is presented. For a plasma generator filled with low-pressure air and parallel-plate electrodes, the model is numerical solved. The space-time distribution of parameters and the spatial distribution of some time-averaged parameters in plasma, which show the physical picture of the RF glow discharge, are obtained

  13. Simulation of nonstationary phenomena in atmospheric-pressure glow discharge

    Science.gov (United States)

    Korolev, Yu. D.; Frants, O. B.; Nekhoroshev, V. O.; Suslov, A. I.; Kas'yanov, V. S.; Shemyakin, I. A.; Bolotov, A. V.

    2016-06-01

    Nonstationary processes in atmospheric-pressure glow discharge manifest themselves in spontaneous transitions from the normal glow discharge into a spark. In the experiments, both so-called completed transitions in which a highly conductive constricted channel arises and incomplete transitions accompanied by the formation of a diffuse channel are observed. A model of the positive column of a discharge in air is elaborated that allows one to interpret specific features of the discharge both in the stationary stage and during its transition into a spark and makes it possible to calculate the characteristic oscillatory current waveforms for completed transitions into a spark and aperiodic ones for incomplete transitions. The calculated parameters of the positive column in the glow discharge mode agree well with experiment. Data on the densities of the most abundant species generated in the discharge (such as atomic oxygen, metastable nitrogen molecules, ozone, nitrogen oxides, and negative oxygen ions) are presented.

  14. Simulation of nonstationary phenomena in atmospheric-pressure glow discharge

    International Nuclear Information System (INIS)

    Korolev, Yu. D.; Frants, O. B.; Nekhoroshev, V. O.; Suslov, A. I.; Kas’yanov, V. S.; Shemyakin, I. A.; Bolotov, A. V.

    2016-01-01

    Nonstationary processes in atmospheric-pressure glow discharge manifest themselves in spontaneous transitions from the normal glow discharge into a spark. In the experiments, both so-called completed transitions in which a highly conductive constricted channel arises and incomplete transitions accompanied by the formation of a diffuse channel are observed. A model of the positive column of a discharge in air is elaborated that allows one to interpret specific features of the discharge both in the stationary stage and during its transition into a spark and makes it possible to calculate the characteristic oscillatory current waveforms for completed transitions into a spark and aperiodic ones for incomplete transitions. The calculated parameters of the positive column in the glow discharge mode agree well with experiment. Data on the densities of the most abundant species generated in the discharge (such as atomic oxygen, metastable nitrogen molecules, ozone, nitrogen oxides, and negative oxygen ions) are presented.

  15. Spectroscopy and probe diagnostics of dc spherical glow discharge

    International Nuclear Information System (INIS)

    Zhovtyansky, V.A.; Nazarenko, V.G.; Syrotyuk, R.P.

    2016-01-01

    Probe and spectroscopic investigations of a spherical glow discharge (GD) were done in nitrogen and argon plasma. There were obtained the distributions of electron temperature and electron density in a discharge gap as well as plasma potential distribution. These results were compared with theoretical ones and the conclusion about their convergence was done in the present study. Particular attention was paid to the anode processes role in the formation of self-organized structure in a spherical glow discharge. It was shown the necessity of taking into account the possibility of the anode potential drop forming in this discharge region

  16. Multiplicity detector using a glow-discharge memory

    International Nuclear Information System (INIS)

    Mulera, T.; Elola, M.; Perez-Mendez, V.; Wiedenbeck, P.

    1981-04-01

    It has been proposed to eliminate the x-y cor relation ambiguities introduced by multiple tracks in a wire chamber by using the chamber itself as a memory. Hits in the chamber itself ignite glow discharges storing the x-y location of the hits in a correlated fashion. Glow ignition may be achieved by employing a multi-step avalanche chamber above a memory gap. Correlation is maintained during readout by successively pulsing each hit wire in one coordinate and sensing transmissions through glows in the other coordinate. Prototypes constructed by the authors are discussed along with the associated high voltage and readout systems

  17. Laser ablation/ionization studies in a glow discharge

    International Nuclear Information System (INIS)

    Hess, K.R.; Harrison, W.W.

    1985-01-01

    The pin cathode glow discharge is used in the laboratory as an atomization/ionization source for a variety of applications, including solids mass spectrometry. Coupled with a tunable dye laser, the glow discharge may also serve as an atom reservoir for resonance ionization mass spectrometry in which the laser ionizes the discharge sputtered atoms. By tightly focusing the laser onto solid samples, various ablation effects may also be investigated. The laser may be used to generate an ionized plasma which may be directly analyzed by mass spectrometry. Alternatively, the ablated neutral atoms may be used in post-ablation excitation/ionization processes, in this case the glow discharge. The results of these investigations are the basis of this paper

  18. Spectroscopic characterisation of an atmospheric pressure glow discharge

    International Nuclear Information System (INIS)

    Gomez, S.; Steen, P.G.; Morrow, T.; Graham, W.G.

    2001-01-01

    Recently there has been considerable interest in atmospheric discharges operating in a glow discharge mode i.e. with a spatial and sheath structure similar to that of low pressure glow discharges. Here spectroscopy has been used to characterise an atmospheric pressure glow discharge (APGD), operating with either dry air, argon or helium gas flowing through the inter-electrode space and with the inter-electrode gap either free or with woven polypropylene or polyester samples present. Emission spectroscopy is used to determine the rotational and vibrational temperature of the nitrogen gas, while electron temperatures are determined from the relative intensities of Ar emission lines. Ozone production is monitored by a simple absorption technique to evaluate its potential in process control

  19. Extension of spatiotemporal chaos in glow discharge-semiconductor systems.

    Science.gov (United States)

    Akhmet, Marat; Rafatov, Ismail; Fen, Mehmet Onur

    2014-12-01

    Generation of chaos in response systems is discovered numerically through specially designed unidirectional coupling of two glow discharge-semiconductor systems. By utilizing the auxiliary system approach, [H. D. I. Abarbanel, N. F. Rulkov, and M. M. Sushchik, Phys. Rev. E 53, 4528-4535 (1996)] it is verified that the phenomenon is not a chaos synchronization. Simulations demonstrate various aspects of the chaos appearance in both drive and response systems. Chaotic control is through the external circuit equation and governs the electrical potential on the boundary. The expandability of the theory to collectives of glow discharge systems is discussed, and this increases the potential of applications of the results. Moreover, the research completes the previous discussion of the chaos appearance in a glow discharge-semiconductor system [D. D. Šijačić U. Ebert, and I. Rafatov, Phys. Rev. E 70, 056220 (2004).].

  20. [The glow discharge as an atomization and ionization source

    International Nuclear Information System (INIS)

    1990-01-01

    This is to summarize the research progress in this project at the University of Florida over the past 13 months. In keeping with the directions of the Federal Demonstration Project, the report will be brief, presenting an overview of the major findings. We have continued the study of the glow discharge, primarily as an ionization source for elemental analysis. Glow discharge interest continues to grow in the analytical chemistry community as evidenced by the number of special symposia at major conferences, by the new researchers entering the field, and by the introduction of new instrumentation. There is little doubt that glow discharge mass spectrometry, for example, is now a major technique in the elemental analysis of solids

  1. Target surface condition during reactive glow discharge sputtering of copper

    International Nuclear Information System (INIS)

    Depla, D; Haemers, J; Gryse, R De

    2002-01-01

    During reactive glow discharge sputtering of copper in an argon/nitrogen plasma, we noticed an abrupt change of the target voltage and the deposition rate when the nitrogen concentration in the plasma exceeds a critical value. To explain this behaviour, the target surface after reactive glow discharge sputtering was examined by x-ray photoelectron spectroscopy (XPS). An experimental arrangement was constructed that allows direct transfer of the glow discharge cathode to the XPS analysis chamber without air exposure. These XPS measurements revealed that several different chemical states of nitrogen are present in the layer that forms on the target surface. The relative concentration of these different states changes when the critical nitrogen concentration in the plasma is exceeded

  2. Extension of spatiotemporal chaos in glow discharge-semiconductor systems

    International Nuclear Information System (INIS)

    Akhmet, Marat; Fen, Mehmet Onur; Rafatov, Ismail

    2014-01-01

    Generation of chaos in response systems is discovered numerically through specially designed unidirectional coupling of two glow discharge-semiconductor systems. By utilizing the auxiliary system approach, [H. D. I. Abarbanel, N. F. Rulkov, and M. M. Sushchik, Phys. Rev. E 53, 4528–4535 (1996)] it is verified that the phenomenon is not a chaos synchronization. Simulations demonstrate various aspects of the chaos appearance in both drive and response systems. Chaotic control is through the external circuit equation and governs the electrical potential on the boundary. The expandability of the theory to collectives of glow discharge systems is discussed, and this increases the potential of applications of the results. Moreover, the research completes the previous discussion of the chaos appearance in a glow discharge-semiconductor system [D. D. Šijačić U. Ebert, and I. Rafatov, Phys. Rev. E 70, 056220 (2004).

  3. Bulk plasma properties in the pulsed glow discharge

    International Nuclear Information System (INIS)

    Jackson, Glen P.; King, Fred L.

    2003-01-01

    This work focuses on the spatial and temporal characteristics of a glow discharge plasma operated with power pulses of 5 ms in duration at 25% duty cycle. Interpretation of emission data provides insight into the nature of the plasma at each instant of a typical pulse cycle and at each position in space. Because the bulk plasma properties affect the distribution of excited energy levels of the sputtered atoms, an improved understanding of the plasma affords the ability to select conditions that enhance analytically important emission lines. Optical emission spectroscopy was used to determine the relative populations of excited states for atoms and ions during the initial breakdown, the steady state and the recombining periods of the discharge pulse cycle. The plasma is highly ionizing in nature at the time of breakdown--with lower excited states being overpopulated--before reaching the steady state, or plateau, period, also ionizing in nature. These behaviors arise from a loss of charged particles and photons to the surroundings that shifts the plasma away from Saha and Boltzmann balances during these periods. The post-pulse period typically displays recombining behavior, characterized by population inversion for selected species--except for regions close to the cathode, where electrons and ions are lost by diffusion and are not available for recombination. The sputtered analyte atom emissions closely mimic those of the plasma bath gas, except that their emissions persevere for longer in the recombining after-peak period than do the discharge gas species

  4. Surface analysis of uranyl fluoride layers with a glow discharge lamp

    International Nuclear Information System (INIS)

    Nel, J.T.; Stander, C.M.; Boehmer, R.G.

    1991-01-01

    Surface analysis with a Grimm-type glow discharge lamp was used to analyse uranyl fluoride layers that had formed on a nickel substrate after exposure to UF 6 . Narrow-band optical filters were used to isolate the intensities of three fluorine emission lines. An in-depth profile of layer composition was obtained. (author)

  5. Oxidation of 1020 steel in the abnormal glow discharge

    International Nuclear Information System (INIS)

    Zúñiga, J A García; Santos, A Sarmiento; Gómez, E Y Soto

    2017-01-01

    1020 steel is a material very used for surface treatment in the abnormal glow discharge. Because the composition of the gaseous atmosphere has an important influence on the results of plasma treatment, in this work the oxidation process of 1020 steel is verified on the abnormal glow discharge under different concentrations of air (20% to 100%) at temperatures of 600°C and 900°C. For each atmosphere used mass variation is measured during the process of surface oxidation, the structure and microstructure of the oxide film formed is observed and also its mechanical properties through its microhardness. (paper)

  6. [Automatic adjustment control system for DC glow discharge plasma source].

    Science.gov (United States)

    Wan, Zhen-zhen; Wang, Yong-qing; Li, Xiao-jia; Wang, Hai-zhou; Shi, Ning

    2011-03-01

    There are three important parameters in the DC glow discharge process, the discharge current, discharge voltage and argon pressure in discharge source. These parameters influence each other during glow discharge process. This paper presents an automatic control system for DC glow discharge plasma source. This system collects and controls discharge voltage automatically by adjusting discharge source pressure while the discharge current is constant in the glow discharge process. The design concept, circuit principle and control program of this automatic control system are described. The accuracy is improved by this automatic control system with the method of reducing the complex operations and manual control errors. This system enhances the control accuracy of glow discharge voltage, and reduces the time to reach discharge voltage stability. The glow discharge voltage stability test results with automatic control system are provided as well, the accuracy with automatic control system is better than 1% FS which is improved from 4% FS by manual control. Time to reach discharge voltage stability has been shortened to within 30 s by automatic control from more than 90 s by manual control. Standard samples like middle-low alloy steel and tin bronze have been tested by this automatic control system. The concentration analysis precision has been significantly improved. The RSDs of all the test result are better than 3.5%. In middle-low alloy steel standard sample, the RSD range of concentration test result of Ti, Co and Mn elements is reduced from 3.0%-4.3% by manual control to 1.7%-2.4% by automatic control, and that for S and Mo is also reduced from 5.2%-5.9% to 3.3%-3.5%. In tin bronze standard sample, the RSD range of Sn, Zn and Al elements is reduced from 2.6%-4.4% to 1.0%-2.4%, and that for Si, Ni and Fe is reduced from 6.6%-13.9% to 2.6%-3.5%. The test data is also shown in this paper.

  7. Velocity persistence of Brownian particles generated in a glow discharge

    International Nuclear Information System (INIS)

    Hurd, A.J.; Ho, P.

    1989-01-01

    Quasielastic light scattering from Brownian particles in the rarefied environment of a glow discharge exhibits Gaussianlike intensity correlation functions owing to the long mean free paths of the particles. The shape of the correlation function depends on the particles' average thermal velocity and friction coefficient, which can be related to aggregate mass and structure, and indicates a crossover from kinetic to hydrodynamic behavior

  8. Time dependent argon glow discharge treatment of Al-alloy

    Indian Academy of Sciences (India)

    The energy dispersive microanalysis by X-rays (EDX) is used to determine ... surface preparation of vacum components and vacuum system of any size. ... In this work, samples of aluminium alloy are treated under dc glow discharge .... (ii) For ałuninium, iron and germanium, relative weight percentage decreases or in-.

  9. Silicon solar cells made by ion implantation and glow discharge

    International Nuclear Information System (INIS)

    Ponpon, J.P.; Siffert, P.

    1975-01-01

    Three different methods of silicon solar cell preparation are considered and investigated: low energy implantation, glow discharge and prebombarded Schottky barriers. The properties of the contact layers realized by these processes are compared in terms of junction depth and sheet resistance. Preliminary results show the usefulness of these techniques for terrestrial solar cell realization [fr

  10. Spectroscopic Study of Electrical Glow Discharges in Gases

    Science.gov (United States)

    Reyes, P. G.; Evangelista, M.; Trujillo, C.; Castillo, F.; Rangel, J.

    2006-12-01

    The variation of the power of the light emitted in a Glow Discharge in Gases of low pressure (GDGLP) excited by a DC source was studied. A lack of dependency of the kind of gas used and the pressure it is located at was obtained. This is comparable to the potential drop which takes place in the discharge by inelastic collisions such as ionization, recombination, excitation, relaxation, etc.

  11. Adaptation of a radiofrequency glow discharge optical emission spectrometer (RF-GD-OES) to the analysis of light elements (carbon, nitrogen, oxygen and hydrogen) in solids: glove box integration for the analysis of nuclear samples

    International Nuclear Information System (INIS)

    Hubinois, J.-C.

    2001-01-01

    The purpose of this work is to use the radiofrequency glow discharge optical emission spectrometry in order to quantitatively determine carbon, nitrogen, oxygen and hydrogen at low concentration (in the ppm range) in nuclear materials. In this study, and before the definitive contamination of the system, works are carried out on non radioactive materials (steel, pure iron, copper and titanium). As the initial apparatus could not deliver a RF power inducing a reproducible discharge and was not adapted to the analysis of light elements: 1- The radiofrequency system had to be changed, 2- The systems controlling gaseous atmospheres had to be improved in order to obtain analytical signals stemming strictly from the sample, 3- Three discharge lamps had to be tested and compared in terms of performances, 4- The system of collection of light had to be optimized. The modifications that were brought to the initial system improved intensities and stabilities of signals which allowed lower detection limits (1000 times lower for carbon). These latter are in the ppm range for carbon and about a few tens of ppm for nitrogen and oxygen in pure irons. Calibration curves were plotted in materials presenting very different sputtering rates in order to check the existence of a 'function of analytical transfer' with the purpose of palliating the lack of reference materials certified in light elements at low concentration. Transposition of this type of function to other matrices remains to be checked. Concerning hydrogen, since no usable reference material with our technique is available, certified materials in deuterium (chosen as a surrogate for hydrogen) were studied in order to exhibit the feasibility the analysis of hydrogen. Parallel to these works, results obtained by modeling a RF discharge show that the performances of the lamp can be improved and that the optical system must be strictly adapted to the glow discharge. (author) [fr

  12. Dust acoustic waves in a dc glow-discharge plasma

    International Nuclear Information System (INIS)

    Molotkov, V.I.; Nefedov, A.P.; Torchinskii, V.M.; Fortov, V.E.; Khrapak, A.G.

    1999-01-01

    The spontaneous excitation of low-frequency oscillations of the macroparticle density in ordered dust structures levitating in standing striations of a dc glow discharge is discovered. It is concluded on the basis of a simplified linear model of an ideal collisionless plasma that the observed instability is caused by the drift motion of ions relative to the dust, which leads to the excitation of dust acoustic oscillations of the plasma

  13. Diode laser excited optogalvanic spectroscopy of glow discharges

    International Nuclear Information System (INIS)

    Barshick, C. M.; Shaw, R. W.; Jennings, L. W.; Post-Zwicker, A.; Young, J. P.; Ramsey, J. M.

    1997-01-01

    The development of diode-laser-excited isotopically-selective optogalvanic spectroscopy (OGS) of uranium metal, oxide and fluoride in a glow discharge (GD) is presented. The technique is useful for determining 235 U/( 235 U+ 238 U) isotope ratios in these samples. The precision and accuracy of this determination is evaluated, and a study of experimental parameters pertaining to optimization of the measurement is discussed. Application of GD-OGS to other f-transition elements is also described

  14. Diode laser excited optogalvanic spectroscopy of glow discharges

    International Nuclear Information System (INIS)

    Barshick, C.M.; Shaw, R.W.; Post-Zwicker, A., Young, J.P.; Ramsey, J.M.

    1996-01-01

    The development of diode-laser-excited isotopically-selective optogalvanic spectroscopy (OGS) of uranium metal, oxide and fluoride in a glow discharge (GD) is presented. The technique is useful for determining isotopic ratios of 235 U/( 235 U + 238 U) in the above samples. The precision and accuracy of this determination is evaluated, and a study of experimental parameters pertaining to optimization of he measurement is discussed. Application of the GD-OGS to other f-transition elements is also described

  15. Electric probe data analysis for glow discharge diagnostics

    International Nuclear Information System (INIS)

    Cain, B.L.

    1987-01-01

    This report summarizes the development and application of digital computations for the analysis of data from an electric probe used for glow discharge diagnostics. The essential physics of the probe/discharge interaction is presented, along with formulations from modern electric probe theory. These results are then digitally implemented by a set of computer programs which both calculate discharge properties of electron temperature and density, and aid in the interpretation of these property estimates. The method of analysis, and the theories selected for implementation, are valid only for low pressure, collisionless sheath, and quiescent discharges where the single electric probe has a much smaller area than the discharge reference electrode. However, certain algorithms are included which, in some cases, can extend the analysis into intermediate pressure regimes. The digital programs' functional capabilities are demonstrated by the analysis of experimental probe data, collected using a laboratory glow discharge. Typical sources of error inherent in the electric probe method are discussed, along with an analysis of error induced by the computational methods of the programs. 27 refs., 49 figs., 20 tabs

  16. Gas Temperature Measurement in a Glow Discharge Plasma

    Science.gov (United States)

    Sloneker, Kenneth; Podder, Nirmol; McCurdy, William E.; Shi, Shi

    2009-10-01

    In this study a relatively inexpensive quartz protected thermocouple is used to measure the gas temperature in the positive column of a glow discharge plasma. For simplicity a K-type thermocouple is used to interpret the gas temperature from the sensor voltage at pressures from 0.5 Torr to 15 Torr and discharge currents from 5 mA to 120 mA. Gas temperature is investigated as a function of the gas pressure at fixed discharge currents and as a function of discharge current at fixed gas pressures in three different gas species (Ar, N2, and He). An infinite cylinder model is used to compute the average gas temperature of the discharge from joule heating and gas thermal conductivity. The model and measurement data agree within 1% to 10% depending on plasma parameters. Data for all three gases have a similar quasi-linear increasing error as compared to the model.

  17. Modeling of Pulsed Direct-Current Glow Discharge

    International Nuclear Information System (INIS)

    Du Mu; Zheng Yaru; Fan Yujia; Zhang Nan; Liu Chengsen; Wang Dezhen

    2010-01-01

    A self-consistent model was adopted to study the time evolution of low-voltage pulsed DC glow discharge. The distributions of electric field, ion density and electron density in nitrogen were investigated in our simulation, and the temporal shape of the discharge current was also obtained. Our results show that the dynamic behaviors of the discharge depends strongly on the applied pulse voltage, and the use of higher pulse voltages results in a significantly increase of discharge current and a decrease of discharge delay time. The current-voltage characteristic calculated by adjusting secondary electron emission coefficient for different applied pulse voltage under the gas pressure of 1 Torr is found in a reasonable agreement with the experimental results.

  18. Use of glow discharge in measurement of diffusion profile

    International Nuclear Information System (INIS)

    Baudin, Guy

    1976-05-01

    The composition of a glow discharge plasma is a good image of the composition of the surface being erroded without fusion. The depth of metal eated away is a linear function of time in 10 to 60μ range, that is too say between 2 and 20 minutes after lightning of the lamp. So measuring the emission of the discharge is function of time gives the diffusion profile of elements either by measuring instantaneous signal or by integrating during short periods of time for weak concentration. Examples of application for diffusion of N 2 and C in steel will be given [fr

  19. Integrated Computer Controlled Glow Discharge Tube

    Science.gov (United States)

    Kaiser, Erik; Post-Zwicker, Andrew

    2002-11-01

    An "Interactive Plasma Display" was created for the Princeton Plasma Physics Laboratory to demonstrate the characteristics of plasma to various science education outreach programs. From high school students and teachers, to undergraduate students and visitors to the lab, the plasma device will be a key component in advancing the public's basic knowledge of plasma physics. The device is fully computer controlled using LabVIEW, a touchscreen Graphical User Interface [GUI], and a GPIB interface. Utilizing a feedback loop, the display is fully autonomous in controlling pressure, as well as in monitoring the safety aspects of the apparatus. With a digital convectron gauge continuously monitoring pressure, the computer interface analyzes the input signals, while making changes to a digital flow controller. This function works independently of the GUI, allowing the user to simply input and receive a desired pressure; quickly, easily, and intuitively. The discharge tube is a 36" x 4"id glass cylinder with 3" side port. A 3000 volt, 10mA power supply, is used to breakdown the plasma. A 300 turn solenoid was created to demonstrate the magnetic pinching of a plasma. All primary functions of the device are controlled through the GUI digital controllers. This configuration allows for operators to safely control the pressure (100mTorr-1Torr), magnetic field (0-90Gauss, 7amps, 10volts), and finally, the voltage applied across the electrodes (0-3000v, 10mA).

  20. Research on the Plasma Anemometer Based on AC Glow Discharge

    Directory of Open Access Journals (Sweden)

    Bing Yu

    2017-01-01

    Full Text Available A new plasma anemometer based on AC glow discharge is designed in this article. Firstly, theoretical analysis of plasma anemometer working principle is introduced to prove the feasibility of the experimental measurement method. Then the experiments are carried out to study the effects of different parameters on the static discharge characteristics of the plasma anemometer system, by which the system optimization methods are obtained. Finally, several groups of appropriate parameters are selected to build the plasma anemometer system based on resistance capacitance coupling negative feedback AC glow discharge, and different airflow speeds are applied to obtain the achievable velocity measurement range. The results show that there is a linear relationship between airflow velocity and discharge current in an allowable error range, which can be applied for airflow velocity measurement. Negative feedback coupling module, which is composed of the coupling resistance and the coupling capacitance, has good effects on improving the system stability. The measurement range of the airflow velocity is significantly increased when the electrode gap is 3 mm, coupling resistance is 470 Ω, and coupling capacitance is 220 pF.

  1. 2D DC Subnormal Glow Discharge in Argon

    International Nuclear Information System (INIS)

    Bouchikhi, A.; Hamid, A.

    2010-01-01

    A two-dimensional time-dependent fluid model was developed and used to describe a DC subnormal glow discharge in argon with Cartesian geometry. This configuration allows us to take into account the transverse expansion of the discharge. A hydrodynamic fluid model used in this paper is based on the moments of the Boltzmann transport equation. The resultant set of governing equations consists of continuity equations (fluxes and densities) for electrons and ions, an energy equation for electrons, and Poisson's equation. Simulation results are presented for the densities of charged particles, the electric voltage, the electric field, and the electron temperature of the discharge. The results were compared with those obtained in the literature.

  2. Shock wave interaction with pulsed glow discharge and afterglow plasmas

    International Nuclear Information System (INIS)

    Podder, N.K.; LoCascio, A.C.

    2009-01-01

    Acoustic shock waves are launched by the spark-discharge of a high voltage capacitor in pulsed glow discharge and afterglow plasmas. The glow discharge section of the shock tube is switched on for a period of less than one second at a time, during which a shock wave is launched starting with a large delay between the plasma switch-on and the shock-launch. In the subsequent runs this delay is decremented in equal time intervals up to the plasma switch-on time. A photo acoustic deflection method sensitive to the density gradient of the shock wave is used to study the propagating shock structure and velocity in the igniting plasma. A similar set of measurements are also performed at the plasma switch-off, in which the delay time is incremented in equal time intervals from the plasma switch-off time until the afterglow plasma fully neutralizes itself into the room-temperature gas. Thus, complete time histories of the shock wave propagation in the igniting plasma, as well as in the afterglow plasma, are produced. In the igniting plasma, the changes in the shock-front velocity and dispersion are found to be a strong non-linear function of delay until a saturation point is reached. On the other hand, in the afterglow plasma the trend has been opposite and reversing towards the room temperature values. The observed shock wave properties in both igniting and afterglow plasmas correlate well with the inferred temperature changes in the two plasmas

  3. Closed form analytic solutions describing glow discharge plasma

    International Nuclear Information System (INIS)

    Pai, S.T.; Guo, X.M.; Zhou, T.D.

    1996-01-01

    On the basis of an analytic model developed previously [S. T. Pai, J. Appl. Phys. 71, 5820 (1992)], an improved version of the model for the description of dc glow discharge plasma was successfully developed. A set of closed form solutions was obtained from the governing equations. The two-dimensional, analytic solutions are functional and completely satisfy the governing equations, the actual boundary conditions, and Maxwell equations. They can be readily used to carry out numerical calculations without the necessity of employing any assumed boundary conditions. Results obtained from the model reveal that as the discharge gap spacing or pressure increases the maximum value in the electron density distribution moves toward the cathode. At a sufficiently large value of gap spacing, the positive column phenomenon begins to appear in the discharge region. The model has the capability of treating the positive column and negative glow as a continuous system without the necessity of studying them separately. The model also predicts a sharp rise of the positive ion density near the cathode and field reversal in the anode region. Variation of the electrode radius produces little effect on the axial spatial distribution of physical quantities studied. copyright 1996 American Institute of Physics

  4. Discharge current characteristics as an 'electrical method' for glow discharge plasma diagnosis

    International Nuclear Information System (INIS)

    Toma, M.; Paraschivescu, Alina; Morminches, Anisoara

    2001-01-01

    In its simplest form, the glow discharge can be established by passing an electric current through gas between two electrodes. The gas and the electrodes are contained in an insulating envelope. In many technological applications, and not only, the plasma devices are often treated like a black box. There is a series of external parameters or control variables which can be adjusted to obtain a desired effect, namely, the operating voltage, gas pressure, gas nature, gas flow rate, magnetic field strength and magnetic field configuration, electric field geometry, interelectrode distance, and cathode characteristics. The discharge current can be controlled by each of the above control variables. The core idea of this work is the following: a lot of information about the phenomena from the discharge volume, at electrodes or at the discharge bounding wall surface, can be obtained knowing how the change of one of the control parameters influences the discharge current. The following regimes were analyzed: dark discharges (background ionization, saturation regime, Townsend regime, corona regime), glow discharge (the normal and abnormal discharge) and arc discharge (glow to arc transition, non-thermal arcs, thermal arcs). It was concluded that the nonlinearity in the shape of the discharge current characteristics as a function of an external control parameter, can be correlated with the elementary processes and the dynamics of different space charge structures generated in plasma devices. (authors)

  5. Is this an arc or a glow discharge?

    International Nuclear Information System (INIS)

    Puchkarev, V.F.; Bochkarev, M.B.

    1994-01-01

    A well known criterion for distinguishing an arc discharge from a glow discharge is a low voltage drop (10--30 V) and a high current density that varies from a few tens to 10 6 A/cm 2 depending on arc type. The high current density is an attribute of arcs with cathode spots. The authors report here a study of the mechanism of emission in cathode spot arc where they realized a spotless discharge with a low voltage drop (30--50 V) and a high mean current density (10 4 --10 6 A/cm 2 ). The discharge was initiated between a broad cathode and point anode. The cathode was a smooth tungsten sphere electrode of about 100 μm in diameter. The point anode was made of various materials (Mo, Cu, Cd) with initial radius 1 μm. Before the experiment the cathode was cleaned by heating at 2,000 K at high vacuum (10 -8 Torr). The discharge was initiated by self-breakdown when electrodes under the voltage 200--500 V were brought to close proximity with each other. The cathode-anode spacing d at the moment of breakdown was estimated to be < 1 μm. The discharge current was varied within 1--3 A by changing the applied voltage and impedance of coaxial cable generator. The discharge burned during 100--1,000 ns. After the single discharge the cathode and anode were examined with a scanning electron microscope. The cathode surface exposed to the discharge was smooth, i.e. no erosion pits similar to arc craters were found on the cathode surface. The anode was shortened after discharge by 5--50 μm depending on current, material and cone angle. A high current density and low voltage drop implies that this is an arc discharge, while the cold cathode and the absence f cathode spot trace are pertinent to a dense glow discharge. The mechanism of emission involving secondary electron emission is to be discussed

  6. Diode laser excited optogalvanic spectroscopy of glow discharges

    International Nuclear Information System (INIS)

    Barshick, C.M.; Shaw, R.W.; Jennings, L.W.; Post-Zwicker, A.; Young, J.P.; Ramsey, J.M.

    1997-01-01

    The development of diode-laser-excited isotopically-selective optogalvanic spectroscopy (OGS) of uranium metal, oxide and fluoride in a glow discharge (GD) is presented. The technique is useful for determining 235 U/( 235 U+ 238 U) isotope ratios in these samples. The precision and accuracy of this determination is evaluated, and a study of experimental parameters pertaining to optimization of the measurement is discussed. Application of GD-OGS to other f-transition elements is also described. copyright 1997 American Institute of Physics

  7. Experimental study of spatial distribution of Ar glow discharge plasma

    International Nuclear Information System (INIS)

    Guo, X.M.; Zhou, T.D.; Pai, S.T.

    1996-01-01

    The characteristics of the spatial distribution of Ar glow discharge plasma were experimentally investigated. By means of direct comparisons between theory and experiment, the effects of the variation of gap separation, gas pressure, and electrode radius on the spatial distributions of electron density and electric field were studied. Results indicate that the maximum electron density moves toward the cathode as the gap separation or gas pressure increases while variation of electrode radius produces little effect. Predictions from a theoretical model have been experimentally verified. General agreements between theory and experiment were found to be reasonably good except in the cathode region, where discrepancy exists. copyright 1996 American Institute of Physics

  8. The mechanism of nickel ferrite formation by glow discharge effect

    Science.gov (United States)

    Frolova, L. A.

    2018-04-01

    The influence of various factors on the formation of nickel ferrite by the glow discharge effect has been studied. The ferritization process in the system FeSO4-NiSO4-NaOH-H2O has been studied by the methods of potentiometric titration, measurement of electrical conductivity, residual concentrations and apparent sediment volume. It has been established that the process proceeds in a multistage fashion at pH 11-12 with the formation of polyhydroxo complexes, an intermediate compound and the ferrite formation by its oxidation with active radicals.

  9. Uncertainty of relative sensitivity factors in glow discharge mass spectrometry

    Science.gov (United States)

    Meija, Juris; Methven, Brad; Sturgeon, Ralph E.

    2017-10-01

    The concept of the relative sensitivity factors required for the correction of the measured ion beam ratios in pin-cell glow discharge mass spectrometry is examined in detail. We propose a data-driven model for predicting the relative response factors, which relies on a non-linear least squares adjustment and analyte/matrix interchangeability phenomena. The model provides a self-consistent set of response factors for any analyte/matrix combination of any element that appears as either an analyte or matrix in at least one known response factor.

  10. Means of introducing an analyte into liquid sampling atmospheric pressure glow discharge

    Science.gov (United States)

    Marcus, R. Kenneth; Quarles, Jr., Charles Derrick; Russo, Richard E.; Koppenaal, David W.; Barinaga, Charles J.; Carado, Anthony J.

    2017-01-03

    A liquid sampling, atmospheric pressure, glow discharge (LS-APGD) device as well as systems that incorporate the device and methods for using the device and systems are described. The LS-APGD includes a hollow capillary for delivering an electrolyte solution to a glow discharge space. The device also includes a counter electrode in the form of a second hollow capillary that can deliver the analyte into the glow discharge space. A voltage across the electrolyte solution and the counter electrode creates the microplasma within the glow discharge space that interacts with the analyte to move it to a higher energy state (vaporization, excitation, and/or ionization of the analyte).

  11. Synthesis of nanoparticles in an atmospheric pressure glow discharge

    International Nuclear Information System (INIS)

    Barankin, M.D.; Creyghton, Y.; Schmidt-Ott, A.

    2006-01-01

    Nanopowders are produced in a low temperature, non-equilibrium plasma jet (APPJ), which produces a glow discharge at atmospheric pressure, for the first time. Amorphous carbon and iron nanoparticles have been synthesized from Acetylene and Ferrocene/H 2 , respectively. High generation rates are achieved from the glow discharge at near-ambient temperature (40-80 deg. C), and rise with increasing plasma power and precursor concentration. Fairly narrow particle size distributions are measured with a differential mobility analyzer (DMA) and an aerosol electrometer (AEM), and are centered around 30-35 nm for carbon and 20-25 nm for iron. Particle characteristics analyzed by TEM and EDX reveal amorphous carbon and iron nanoparticles. The Fe particles are highly oxidized on exposure to air. Comparison of the mobility and micrograph diameters reveal that the particles are hardly agglomerated or unagglomerated. This is ascribed to the unipolar charge on particles in the plasma. The generated particle distributions are examined as a function of process parameters

  12. Boundary Effect of Planar Glow Dielectric Barrier Discharge and Its Influence on the Discharge Structure

    International Nuclear Information System (INIS)

    Xu Shaowei; Li Lulu; Ouyang Jiting

    2015-01-01

    The dielectric barrier discharge (DBD) in the glow regime in neon has been investigated by experiment and two-dimensional (2D) fluid modeling. The discharge was carried out in a planar DBD system with segmented-electrodes driven by square-wave voltage. The results show that the glow DBD originates in the center of the electrode and expands outward to the electrode edge during each half cycle of the voltage, forming a radial structure. The discharge decays firstly in the inner area but sustains longer in the edge area, showing a reversed discharge area. The discharge cannot completely cover the entire electrode surface, but remains a border of non- or weak discharge. The fluid modeling shows a similar result in agreement with the experiments. The simulations indicate that the electric field in the edge area is distorted due to the boundary effect so that the electric field and charge distribution are different from that in the inner part. The distorted field reduces the longitudinal component near the edge and causes the local field to be lower than that in the center, and hence makes the discharge behindhand. It also induces a transverse field that makes the discharge extend radially outward to the edge. The boundary effect plays an important role in the glow DBD structure. (paper)

  13. Bidimensional characterization of the emission spectra in a direct current atmospheric pressure glow discharge

    International Nuclear Information System (INIS)

    Orejas, Jaime; Pisonero, Jorge; Bordel, Nerea; Nelis, Thomas; Guillot, Philippe; Sanz-Medel, Alfredo

    2012-01-01

    An in-house atmospheric pressure glow discharge source, designed to be used as ionization/desorption source for ambient mass spectrometry, has been electrically characterized, and its optical emission spectra evaluated in detail. Electrical characterization showed that the plasma regime can vary from glow discharge to arc discharge depending on operating conditions (i.e. He flow rate and inter electrode distance). Furthermore, bidimensional images of the optical emission of some plasma species using filters as wavelength selectors, were registered from inside and outside the discharge chamber (inner region and afterglow region respectively), showing the spatial distribution of excited species (i.e. He*, N 2 + and O*). These distribution patterns are useful to study the chemistry of the discharge plasma, since different production pathways and different excitation energies affect the presence of these species in the plasma regions. - Highlights: ► An in-house APGD is characterized through electrical and OES measurements. ► Interelectrode distance had more effect on electric regime than He flow rate. ► Internal plume images showed differences on the production pathways for each species. ► Higher interelectrode distances and He flow rates showed better afterglow conditions.

  14. Bidimensional characterization of the emission spectra in a direct current atmospheric pressure glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Orejas, Jaime [University of Oviedo, Department of Physics, C/ Gonzazlez Quiros S/N, Mieres (Spain); Pisonero, Jorge, E-mail: pisonerojorge@uniovi.es [University of Oviedo, Department of Physics, C/ Gonzazlez Quiros S/N, Mieres (Spain); Bordel, Nerea [University of Oviedo, Department of Physics, C/ Gonzazlez Quiros S/N, Mieres (Spain); Nelis, Thomas [Bern University of Applied Sciences, Quellgasse 21, 2501 Bienne (Switzerland); Guillot, Philippe [DPHE, CUFR J. F. Champollion, Universite de Toulouse, Place de Verdun, Albi (France); Sanz-Medel, Alfredo, E-mail: asm@uniovi.es [University of Oviedo, Department of Physical and Analytical Chemistry, C/ Julian Claveria 8, Oviedo (Spain)

    2012-10-15

    An in-house atmospheric pressure glow discharge source, designed to be used as ionization/desorption source for ambient mass spectrometry, has been electrically characterized, and its optical emission spectra evaluated in detail. Electrical characterization showed that the plasma regime can vary from glow discharge to arc discharge depending on operating conditions (i.e. He flow rate and inter electrode distance). Furthermore, bidimensional images of the optical emission of some plasma species using filters as wavelength selectors, were registered from inside and outside the discharge chamber (inner region and afterglow region respectively), showing the spatial distribution of excited species (i.e. He*, N{sub 2}{sup +} and O*). These distribution patterns are useful to study the chemistry of the discharge plasma, since different production pathways and different excitation energies affect the presence of these species in the plasma regions. - Highlights: Black-Right-Pointing-Pointer An in-house APGD is characterized through electrical and OES measurements. Black-Right-Pointing-Pointer Interelectrode distance had more effect on electric regime than He flow rate. Black-Right-Pointing-Pointer Internal plume images showed differences on the production pathways for each species. Black-Right-Pointing-Pointer Higher interelectrode distances and He flow rates showed better afterglow conditions.

  15. Determination of the plasma impedance of a glow discharge in carbon dioxide

    Science.gov (United States)

    Kiselev, A. S.; Smirnov, E. A.

    2017-07-01

    In this work an expression for the dynamic resistance of a glow discharge flowing in long tubes is obtained and analyzed. The expression describes the physical processes occurring in the positive column of a glow discharge. The frequency dependences of the active and reactive components as well as the dynamic resistance module for the discharge conditions corresponding to CO2-lasers have been calculated. Based on the simulation results developed a computer program in the C# programming language for modeling the dynamic resistance discharge of glow discharge lasers.

  16. Thermal mechanism of prepeak formation in Pulsed Glow Discharge

    Science.gov (United States)

    Voronov, Maxim; Hoffmann, Volker; Steingrobe, Tobias; Buscher, Wolfgang; Engelhard, Carsten; Storey, Andrew; Ray, Steven; Hieftje, Gary

    2012-10-01

    A microsecond Pulsed Glow Discharge (μs PGD) in a Grimm-type source is characterized by the so-called ``prepeak,'' which is a spike in both electrical current and emission intensity at the leading edge of the discharge pulse. The prepeak is followed by synchronized vibrations of the current and the emission. To understand the nature of these phenomena, a microphone was inserted into the discharge chamber. Acoustical waves were detected and found to be in correlation with the measured vibrations. This points to a thermal mechanism for prepeak formation: the gas is heated in the leading edge of the discharge pulse and then expanded. To prove this suggestion, a Monte-Carlo based model was developed to simulate the evolution of Ar concentration, temperature, and flow in time and space. Potentially, the model could be used for gas simulations in a wide range of different applications. Here, the model is incorporated into an existing but modified model of the μs PGD in a Grimm-type plasma excitation source. Results of the simulations confirm that the thermal mechanism is responsible for the formation of the electrical prepeak and the pressure waves.

  17. [Determination of electric field distribution in dielectric barrier surface glow discharge by spectroscopic method].

    Science.gov (United States)

    Li, Xue-chen; Jia, Peng-ying; Liu, Zhi-hui; Li, Li-chun; Dong, Li-fang

    2008-12-01

    In the present paper, stable glow discharges were obtained in air at low pressure with a dielectric barrier surface discharge device. Light emission from the discharge was detected by photomultiplier tubes and the research results show that the light signal exhibited one discharge pulse per half cycle of the applied voltage. The light pulses were asymmetric between the positive half cycle and the negative one of the applied voltage. The images of the glow surface discharge were processed by Photoshop software and the results indicate that the emission intensity remained almost constant for different places with the same distance from the powered electrode, while the emission intensity decreased with the distance from the powered electrode increasing. In dielectric barrier discharge, net electric field is determined by the applied voltage and the wall charges accumulated on the dielectric layer during the discharge, and consequently, it is important to obtain information about the net electric field distribution. For this purpose, optical emission spectroscopy method was used. The distribution of the net electric field can be deduced from the intensity ratio of spectral line 391.4 nm emitted from the first negative system of N2+ (B 2sigma u+ -->X 2sigma g+) to 337.1 nm emitted from the second positive system of N2 (C 3IIu-B 3IIg). The research results show that the electric field near the powered electric field is higher than at the edge of the discharge. These experimental results are very important for numerical study and industrial application of the surface discharge.

  18. In-situ reactive glow discharge cleaning of NSLS distributed ion pumps

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, E.D.; Chou, T.S.

    1988-01-01

    Based on our experience with the in-situ cleaning of optical systems by reactive r.f. glow discharges and the conditioning and preparation of distributed ion pump (DIP) elements, we have sought to develop strategies for recovering from severe vacuum accidents by restoring DIP elements of storage rings such as those at the NSLS in-situ. In this paper we will describe a series of experiments conducted in a test apparatus to condition a so called ''egg-crate'' DIP in-situ, (this older type element being common in older storage rings). A new untreated element which was unable to pump below 5x10 /sup /minus/8/ Torr in its initial condition was treated in oxygen and subsequent argon r.f. discharges utilizing the pump element as the discharge electrode producing a nitrogen pumping speed of 168 l/s at 2x10 /sup /minus/8/ Torr. A light bake at 75/degree/C increased this to nearly 500 l/s at 5x10 /sup /minus/8/ Torr. After exposure to atmosphere the speed was reduced to nil at these pressures but subsequently recovered, without bakeout, by glow discharge cleaning. 22 refs., 6 figs.

  19. In-situ reactive glow discharge cleaning of NSLS distributed ion pumps

    International Nuclear Information System (INIS)

    Johnson, E.D.; Chou, T.S.

    1988-01-01

    Based on our experience with the in-situ cleaning of optical systems by reactive r.f. glow discharges and the conditioning and preparation of distributed ion pump (DIP) elements, we have sought to develop strategies for recovering from severe vacuum accidents by restoring DIP elements of storage rings such as those at the NSLS in-situ. In this paper we will describe a series of experiments conducted in a test apparatus to condition a so called ''egg-crate'' DIP in-situ, (this older type element being common in older storage rings). A new untreated element which was unable to pump below 5x10 /sup /minus/8/ Torr in its initial condition was treated in oxygen and subsequent argon r.f. discharges utilizing the pump element as the discharge electrode producing a nitrogen pumping speed of 168 l/s at 2x10 /sup /minus/8/ Torr. A light bake at 75/degree/C increased this to nearly 500 l/s at 5x10 /sup /minus/8/ Torr. After exposure to atmosphere the speed was reduced to nil at these pressures but subsequently recovered, without bakeout, by glow discharge cleaning. 22 refs., 6 figs

  20. Study on the onset of DC diaphragm glow discharge

    International Nuclear Information System (INIS)

    Jin, Xinglong; Wang, Xiaoyan; Zhang, Hongmei; Ren, Hongxia

    2013-01-01

    In this paper, the DC diaphragm glow discharge (DGD) occurred around the small hole on quartz tube between two submersed graphite electrodes and the onset of DGD was systematically investigated. It was found that critical voltage (V D ) decreased with the increasing conductivity, and then maintained at about 620 V. When the hole diameter increased from 1.0 mm to 2.5 mm, H 2 O 2 formation and AO discoloration in anolyte increased with the increase of the hole diameter. In addition, the effect of electrolyte constituents on H 2 O 2 formation and AO discoloration in anolyte induced by DGD was also studied. The concentration of H 2 O 2 and AO discoloration in anolyte was close in inert electrolyte such as Na 2 SO 4 and Na 2 HPO 4 solution. The concentration of H 2 O 2 and AO discoloration rate in Na 2 CO 3 and NaAc solution was lower than those in Na 2 SO 4 and Na 2 HPO 4 solution, due to their capture ability for ·OH. However, NaCl showed enhancing effect on AO discoloration, although it consumed a certain amount of H 2 O 2 . The energy efficiencies of AO discoloration and H 2 O 2 formation were also compared with those of other DGD reactor.

  1. Iron nitride films formed in a r. f. glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Li, J.L.; O' Keefe, T.J.; James, W.J. (Depts. of Chemistry and Metallurgical Engineering and Graduate Center for Materials Research, Univ. of Missouri-Rolla (United States))

    1992-12-30

    Fe[sub 2]N and Fe[sub 3]N films were deposited on an r.f. glow discharge by introducing Fe(CO)[sub 5] and NH[sub 3] into the reactor. The iron nitride films thus formed exhibited sheet conductivities in the range of 10[sup 2]-10[sup 3] ohm[sup -1] cm[sup -1]. They exhibited microhardness ranging from 578 to 659 kg mm[sup -2] on glass slides. The effects of the deposition temperature and the nature of the substrate material on the structure and composition of the films were investigated. An Fe[sub 4]N layer was formed on iron substrates at 400degC in the plasma nitriding process using NH[sub 3] as the gas source. The Fe[sub 4]N layer exhibited a microhardness of 230 kg mm[sup -2]. The effect of the temperature on the formation of the nitrided layer is discussed. (orig.).

  2. Degradation of Anionic Dye Eosin by Glow Discharge Electrolysis Plasma

    International Nuclear Information System (INIS)

    Gao Jinzhang; Ma Dongping; Guo Xiao; Wang Aixiang; Fu Yan; Wu Jianlin; Yang Wu

    2008-01-01

    This paper describes a novel method for the degradation of eosin by using glow discharge electrolysis (GDE). The effects of various parameters on the removal efficiency were studied. It was found that the eosin degradation could be raised considerably by increasing the applied voltage and the initial concentration, or by decreasing pH of the aqueous solution. Fe 2+ ion had an evident accelerating effect on the eosin degradation. The degradation process of eosin obeyed a pseudo-first-order reaction. The relationship between the degradation rate constant k and the reaction temperature T could be expressed by Arrhenius equation with which the apparent activation energy Ea of 14.110 kJ. mol -1 and the pre-exponential factor ko of 2.065x10 -1 min -1 were obtained, too. The determination of hydroxyl radical was carried out by using N,N-dimethyl-p-nitrosoaniline (RNO) as a scavenger. The results showed that the hydroxyl radical plays an important role in the degradation process.

  3. Degradation of Anionic Dye Eosin by Glow Discharge Electrolysis Plasma

    Science.gov (United States)

    Gao, Jinzhang; Ma, Dongping; Guo, Xiao; Wang, Aixiang; Fu, Yan; Wu, Jianlin; Yang, Wu

    2008-08-01

    This paper describes a novel method for the degradation of eosin by using glow discharge electrolysis (GDE). The effects of various parameters on the removal efficiency were studied. It was found that the eosin degradation could be raised considerably by increasing the applied voltage and the initial concentration, or by decreasing pH of the aqueous solution. Fe2+ ion had an evident accelerating effect on the eosin degradation. The degradation process of eosin obeyed a pseudo-first-order reaction. The relationship between the degradation rate constant k and the reaction temperature T could be expressed by Arrhenius equation with which the apparent activation energy Ea of 14.110 kJ. mol-1 and the pre-exponential factor ko of 2.065×10-1 min-1 were obtained, too. The determination of hydroxyl radical was carried out by using N,N-dimethyl-p-nitrosoaniline (RNO) as a scavenger. The results showed that the hydroxyl radical plays an important role in the degradation process.

  4. Fuel hydrogen retention of tungsten and the reduction by inert gas glow discharges

    Energy Technology Data Exchange (ETDEWEB)

    Hino, T., E-mail: tomhino@qe.eng.hokudai.ac.jp [Laboratory of Plasma Physics and Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Yamauchi, Y.; Kimura, Y. [Laboratory of Plasma Physics and Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Nishimura, K. [National Institute for Fusion Science, Toki-shi, Gifu-ken 509-5292 (Japan); Ueda, Y. [Graduate School of Engineering, Osaka University, Suita-shi 565-0872 (Japan)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer The performances of inert gas glow discharges for reduction of fuel hydrogen retention in tungsten were systematically investigated. Black-Right-Pointing-Pointer For the tungsten with rough surface structure, the reduction of fuel hydrogen retention by inert gas discharges is quite small. Black-Right-Pointing-Pointer The deuterium glow discharge is quite useful to reduce the tritium retention in plasma facing walls in fusion reactor. Black-Right-Pointing-Pointer The wall baking with temperature higher than 700-800 K is also useful to reduce the tritium retention in plasma facing walls. - Abstract: Polycrystalline tungsten was exposed to deuterium glow discharge followed by He, Ne or Ar glow discharge. The amount of retained deuterium in the tungsten was measured using residual gas analysis. The amount of desorbed deuterium during the inert gas glow discharge was also measured. The amount of retained deuterium was 2-3 times larger compared with a case of stainless steel. The ratios of desorbed amount of deuterium by He, Ne and Ar glow discharges were 4.6, 3.1 and 2.9%, respectively. These values were one order of magnitude smaller compared with the case of stainless steel. The inert gas glow discharge is not suitable to reduce the fuel hydrogen retention for tungsten walls. However, the wall baking with a temperature higher than 700 K is suitable to reduce the fuel hydrogen retention. It is also shown that the use of deuterium glow discharge is effective to reduce the in-vessel tritium inventory in fusion reactors through the hydrogen isotope exchange.

  5. Comparison of glow discharge cleaning with Taylor-type discharge cleaning on JFT-2

    International Nuclear Information System (INIS)

    Yokokura, Kenji; Matsuzaki, Yoshimi; Tani, Takashi

    1983-01-01

    Method of glow discharge cleaning (GDC) was applied to JFT-2 tokamak and the cleaning effect of GDC was compared with that of taylor-type discharge cleaning (TDC) on the same machin. Results show clearly their individual characteristics to remove light impurities. Their abilities of surface cleaning were compared each other by observing cleanliness of sample surfaces with a AES and by measuring decay times of produced gas pressures during discharge cleanings with a mass-analyser. It was shown that TDC method is better by several times than GDC method from a mass-analyser measurement. Moreover discharge cleaning time necessary to reduce light impurities in the normal plasma to a certain level was compared by monitoring time evolution of radiation loss power with a bolometer, and the time by TDC was only one fifth of that by GDC. The advantage of TDC may come from the excellently high hydrogen flux which interacts with the limiter and the wall. (author)

  6. Study on out-gassing by baking and glow discharge during wall conditioning of vacuum chamber

    International Nuclear Information System (INIS)

    Wang Zhiwen; Wei Weixing; Zhao Yuanqing; He Yanhe; Liao Yikui

    2007-01-01

    The model of out-gassing by baking and glow discharge cleaning (GDC) is set up. The properties of them are studied. Out-gassing by baking is from bulk and it obeys the diffusion equation. Out-gassing of glow discharge cleaning is mainly on surface, it is inducement out-gassing by sputtering. Thus the properties of out-gassing for baking and GDC on the HL-1M tokamak are analyzed. Some empirical formulas are given. (authors)

  7. Effect of volume and surface charges on discharge structure of glow dielectric barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Shao-Wei; He, Feng; Wang, Yu; Li, Lulu; Ouyang, Ji-Ting [School of Physics, Beijing Institute of Technology, Beijing 100081 (China)

    2013-08-15

    The effect of volume and surface charges on the structure of glow dielectric barrier discharge (DBD) has been investigated numerically by using two-dimensional (2D) fluid modeling. The local increase of volume or surface charges induces a kind of activation-inhibition effect, which enhances the local volume discharge and inhibits the discharge in neighborhoods, resulting in non-uniform discharge. The activation-inhibition effect due to the non-uniform volume and/or surface charges depends on the non-uniformity itself and the applied voltage. The activation-inhibition of non-uniform charges has different effects on the volume charges and the accumulated surface charges. The distribution of remaining free charges (seed electrons) in volume at the beginning of voltage pulse plays a key role for the glow DBD structure, resulting in a patterned DBD, when the seed electrons are non-uniform at higher frequency and moderate voltage or uniform DBD, when the seed electrons are uniform at lower frequency or high voltage. The distribution of surface charges is not the determining factor but a result of the formed DBD structure.

  8. Organic chemistry of NH3 and HCN induced by an atmospheric abnormal glow discharge in N2-CH4 mixtures

    OpenAIRE

    2010-01-01

    Abstract The formation of the chemical products produced in an atmospheric glow discharge fed by a N2-CH4 gas mixture has been studied using Fourier Transform InfraRed (FTIR) and Optical Emission Spectrometry (OES). The measurements were carried out in a flowing regime at ambient temperature and pressure with CH4 concentrations ranging from 0.5% to 2%. In the recorded emission spectra the lines of the second positive system CN system and the first negative s...

  9. Properties of the positive column of a glow discharge in flowing hydrogen

    International Nuclear Information System (INIS)

    Brunet, H.; Rocca Serra, J.; Mabru, M.

    1981-01-01

    Results of a theoretical model for predicting the effects of gas flow on the properties of the positive column in a glow discharge are presented. A cylindrical discharge at low pressure ( 2 molecules and H atoms produced by the discharge are calculated. Comparison with available experimental data is made

  10. Analysis of soils by glow discharge mass spectrometry

    International Nuclear Information System (INIS)

    Duckworth, D.C.; Barshick, C.M.; Smith, D.H.

    1993-01-01

    The analysis of soils by conventional solution-based techniques, such as inductively coupled plasma and thermal ionization mass spectrometry, is complicated by the need for sample dissolution or the combination of a solids atomizer with an auxiliary ionization source. Since time is an important consideration in waste remediation, there exists a need for a method of rapidly analysing many soil samples with little sample preparation; glow discharge mass spectrometry (GDMS) has the potential to meet this need. Because GDMS is a bulk solids technique, sample preparation is simplified in comparison to other methods. Even with the most difficult samples (geological materials, such as soils and volcanic rock), all that is required is grinding, drying and mixing with a conducting host material prior to electrode formation. As a first test of GDMS for soil analysis, a National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) was analysed by direct current GDMS. Fifty-one elements were quantified from a single cathode using ion beam ratios and ''standard'' relative elemental sensitivity factors (RSF). Average errors for the suite of elements were less than a factor of 4 and 1.4 for uncorrected and corrected values, respectively. User-generated RSF values were applied to the analysis of several elements in NIST SRM 2704 Buffalo River Sediment. In the absence of isobaric interferences, accuracies ranging from 0.6 to 73% were observed, demonstrating the potential of the technique for the determination of many elements. The presence of entrained water and inhomogeneity resulting from cathode preparation is thought to affect matrix-to-matrix reproducibility. While further success depends on developing means of circumventing mass spectral interferences and addressing factors affecting plasma chemistry, the immediate goal of developing a screening method for priority metals in soils was met. (Author)

  11. Characteristics of an atmospheric pressure argon glow discharge in a coaxial electrode geometry

    International Nuclear Information System (INIS)

    Li Xuechen; Zhao Na; Fang Tongzhen; Liu Zhihui; Li Lichun; Dong Lifang

    2008-01-01

    An atmospheric glow discharge controlled by a dielectric barrier is realized in a coaxial electrode geometry in argon. The discharge characteristics are studied by the electrical method and optical emission spectroscopy. The experimental results indicate that there is only one discharge pulse per half cycle when the applied voltage is very low, and the rise time of the discharge pulses at the positive half cycle is much shorter than that at the negative one. With an increase in applied voltage, the width of the discharge pulse increases, while the inception voltage at which breakdown occurs decreases. The rise time at positive half cycle almost equals that at negative half cycle when the applied voltage is high enough. The research results pertaining to gas gap voltage indicate that the critical electric field for breakdown decreases with increasing applied voltage. The electron temperature is estimated from the Einstein relation, and the result indicates that the electron temperature and the electron density are functions of the applied voltage and the gas flow rate. The electron temperature is also studied by emission spectroscopy and a similar result is obtained

  12. The role of magnetic energy on plasma localization during the glow discharge under reduced pressure

    Directory of Open Access Journals (Sweden)

    Chodun Rafal

    2016-06-01

    Full Text Available In this work, we present the first results of our research on the synergy of fields, electric and magnetic, in the initiation and development of glow discharge under reduced pressure. In the two-electrode system under reduced pressure, the breakdown voltage characterizes a minimum energy input of the electric field to initiate and sustain the glow discharge. The glow discharge enhanced by the magnetic field applied just above the surface of the cathode influences the breakdown voltage decreasing its value. The idea of the experiment was to verify whether the contribution of potential energy of the magnetic field applied around the cathode is sufficiently effective to locate the plasma of glow discharge to the grounded cathode, which, in fact, is the part of a vacuum chamber wall (the anode is positively biased in this case. In our studies, we used the grounded magnetron unit with positively biased anode in order to achieve favorable conditions for the deposition of thin films on fibrous substrates such as fabrics for metallization, assuming that locally applied magnetic field can effectively locate plasma. The results of our studies (Paschen curve with the participation of the magnetic field seem to confirm the validity of the research assumption. What is the most spectacular - the glow discharge was initiated between introduced into the chamber anode and the grounded cathode of magnetron ‘assisted’ by the magnetic field (discharge did not include the area of the anode, which is a part of the magnetron construction.

  13. Effects of the ion-solid interaction in glow discharge vapour deposition polymerization of pyromellitic dianhydride

    International Nuclear Information System (INIS)

    Maggioni, G.; Carturan, S.; Rigato, V.; Pieri, U.

    2000-01-01

    Low energy He ion bombardment of pyromellitic dianhydride monomer used in glow discharge vapour deposition polymerization (GDVDP) of polyimide coatings and its effects on the film deposition process have been studied. The sublimation of the monomer molecules and the simultaneous formation of a damaged, carbon-rich surface layer on the target are discussed from a theoretical point of view based on simulations of the ion-solid interaction. Optical emission and mass spectrometry have been used to analyse the species emitted from the target. In order to study the time evolution of the PMDA target damage, the deposition rate of monomer molecules has been monitored. FT-IR spectroscopy has been used to determine the molecular damaging of the target monomer and deposited films

  14. Surface enrichment with chrome and nitriding of IF steel under an abnormal glow discharge

    International Nuclear Information System (INIS)

    Meira, S.R.; Borges, P.C.; Bernardelli, E.A.

    2014-01-01

    The objective of this work is to evaluate the influence of surface enrichment of IF steel with chrome, and nitriding, the formation of the nitrided layer. Thus, IF steel samples were subjected to surface enrichment process, using 409 stainless steel as a target for sputtering, followed by plasma nitriding, both under a dc abnormal glow discharge. The enrichment treatment was operated at 1200 ° C for 3h. The nitriding treatment was operated at 510 ° C for 2 h. The influence of the treatments on the layers formed was studied through optical microscopy (OM), scan electron microscopy (SEM), X-ray diffraction (XRD) and Vickers microindentation. The results show that the enrichment is effective to enrich the IF surface, furthermore, improves the characteristics of nitriding, comparing nitriding samples to nitriding and enriched, was observed needles of nitrides, as well as a higher hardness, which is associated with the nitrides of chrome, on the nitriding and enriched samples. (author)

  15. Heterodyne detection at 300 GHz using neon indicator lamp glow discharge detector.

    Science.gov (United States)

    Aharon Akram, Avihai; Rozban, Daniel; Kopeika, Natan S; Abramovich, Amir

    2013-06-10

    A miniature neon indicator lamp, also known as a glow discharge detector (GDD), costing about 50 cents, was found to be an excellent room temperature terahertz radiation detector. Proof-of-concept 300 GHz heterodyne detection using GDD is demonstrated in this paper. Furthermore, a comparison to direct detection was carried out as well. Previous results with the GDD at 10 GHz showed 40 times better sensitivity using heterodyne detection compared to direct detection. Preliminary results at 300 GHz showed better sensitivity by a factor of 20 with only 56 μW local-oscillator power using heterodyne compared to direct detection. The higher the local-oscillator power (P(lo)), the better the sensitivity of the detector. Further improvement can be achieved by employing better quasi-optical design.

  16. Effect of silane dilution on intrinsic stress in glow discharge hydrogenated amorphous silicon films

    Science.gov (United States)

    Harbison, J. P.; Williams, A. J.; Lang, D. V.

    1984-02-01

    Measurements of the intrinsic stress in hydrogenated amorphous silicon (a-Si : H) films grown by rf glow discharge decomposition of silane diluted to varying degrees in argon are presented. Films are found to grow under exceedingly high compressive stress. Low values of macroscopic film density and low stress values are found to correlate with high growth rate. An abrupt drop in stress occurs between 2 and 3% silane at precisely the point where columnar growth morphology appears. No corresponding abrupt change is noted in density, growth rate, or plasma species concentrations as determined by optical emissioin spectroscopy. Finally a model of diffusive incorporation of hydrogen or some gaseous impurity during growth into the bulk of the film behind the growing interface is proposed to explain the results.

  17. Glow discharge-deposited amorphous silicon films for low-cost solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Grabmaier, J G; Plaettner, R D; Stetter, W [Siemens A.G., Muenchen (Germany, F.R.). Forschungslaboratorien

    1980-01-01

    Due to their high absorption constant, glow discharge-deposited amorphous silicon (a-Si) films are of great interest for low-cost solar cells. Using SiH/sub 4/ and SiX/sub 4//H/sub 2/ (X = Cl or F) gas mixtures in an inductively or capacitively excited reactor, a-Si films with thicknesses up to several micrometers were deposited on substrates of glass, silica and silicon. The optical and electrical properties of the films were determined by measuring the IR absorption spectra, dark conductivity, photoconductivity, and photoluminescence. Hydrogen, chlorine, or fluorine were incorporated in the films in order to passivate dangling bonds in the amorphous network.

  18. Investigation of plasma potential and pulsed discharge characteristics in enhanced glow discharge plasma immersion ion implantation and deposition

    International Nuclear Information System (INIS)

    Li Liuhe; Lu Qiuyuan; Fu, Ricky K.Y.; Chu, Paul K.

    2009-01-01

    Enhanced glow discharge plasma immersion ion implantation and deposition (EGD-PII and D) does not require external plasma sources. In this technique, the plasma is produced by self-glow discharge when a high negative voltage is applied to the sample. The small-area, pointed-shape hollow anode and large area tabular cathode form an electron-focused electric field. Using a special electric field design, the electrons from either the plasma or target (secondary electrons) are focused to a special hollow anode. As a result of the special electron-focusing field, the self-glow discharge process can be enhanced to achieve effective ion implantation into the substrate. In this work, the plasma potential distribution is investigated in details and the possible pulse discharge mechanism is discussed. The unique characteristics of the pulsed plasma and plasma extinction are studied.

  19. Gas Breakdown of Radio Frequency Glow Discharges in Helium at near Atmospheric Pressure

    International Nuclear Information System (INIS)

    Liu Xinkun; Xu Jinzhou; Cui Tongfei; Guo Ying; Zhang Jing; Shi Jianjun

    2013-01-01

    A one-dimensional self-consistent fluid model was developed for radio frequency glow discharge in helium at near atmospheric pressure, and was employed to study the gas breakdown characteristics in terms of breakdown voltage. The effective secondary electron emission coefficient and the effective electric field for ions were demonstrated to be important for determining the breakdown voltage of radio frequency glow discharge at near atmospheric pressure. The constant of A was estimated to be 64±4 cm −1 Torr −1 , which was proportional to the first Townsend coefficient and could be employed to evaluate the gas breakdown voltage. The reduction in the breakdown voltage of radio frequency glow discharge with excitation frequency was studied and attributed to the electron trapping effect in the discharge gap

  20. Study of plasma characteristics in the cathode regime of a nitrogen glow discharge

    International Nuclear Information System (INIS)

    Margulis, Alvaro

    1987-01-01

    This research thesis reports the study of the cathode region, cathodic sheath and negative glow, of a nitrogen glow discharge. The author first presents general data regarding glow discharges, a description of the experimental installation, and measurements of discharge balancing. In the next part, he precisely describes spectroscopic methods, and the implementation of diagnoses from an experimental point of view as well as in terms of space resolution. Results are then presented and interpreted. Measurements concern space distributions of excited species, the determination of axial and radial concentrations of nitrogen ions, axial variations of rotational temperatures of the different species and variations of nitrogen ion vibrational temperature. The laser optogalvanic effect on the nitrogen molecular ion is resolved in time, and compared with the result of a theoretical model based on the mobility difference between the different nitrogen ions. Finally, the author compares experimental results on ion profiles along the discharge axis with results obtained with theoretical models [fr

  1. Detrapping of tungsten nanoparticles in a direct-current argon glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Couëdel, L., E-mail: lenaic.couedel@univ-amu.fr; Kumar, K. Kishor; Arnas, C. [Laboratoire de Physique des Interactions Ioniques et Moléculaires, CNRS, Aix-Marseille Université, 13397 Marseille (France)

    2014-12-15

    Nanoparticles are grown from the sputtering of a tungsten cathode in a direct current argon glow discharge. Laser light scattering of a vertical laser sheet going through the plasma reveals that the dust particle cloud is compressed and pushed towards the anode during the discharge. Scanning electron microscopy images of substrates exposed to the plasma for given durations show that dust particles are continuously falling down on the anode during the discharge. These observations are explained by the fact that the electrostatic force at the negative glow-anode sheath boundary cannot balance the ion drag, gravity, and thermophoresis forces for particles of more than a few tens of nanometres in diameter.

  2. Period multiplication and chaotic phenomena in atmospheric dielectric-barrier glow discharges

    International Nuclear Information System (INIS)

    Wang, Y. H.; Zhang, Y. T.; Wang, D. Z.; Kong, M. G.

    2007-01-01

    In this letter, evidence of temporal plasma nonlinearity in which atmospheric dielectric-barrier discharges undergo period multiplication and chaos using a one-dimensional fluid model is reported. Under the conditions conducive for chaotic states, several frequency windows are identified in which period multiplication and secondary bifurcations are observed. Such time-domain nonlinearity is important for controlling instabilities in atmospheric glow discharges

  3. Formation and evolution of the glow-like dielectric barrier discharge at atmospheric pressure

    NARCIS (Netherlands)

    Starostin, S.A.; ElSabbagh, M.A.M.; Premkumar, P.A.; Vries, de H.W.; Paffen, R.M.J.; Creatore, M.; Sanden, van de M.C.M.

    2008-01-01

    Time resolved process of formation and evolution of the atmospheric pressure glow discharge was studied in the roll-to- roll plasma- enhanced chemical vapor deposition dielectric barrier discharge reactor operating in helium-free gas mixtures by means of fast ICCD imaging. It was observed that the

  4. Peculiarities of glow modes of argon atmospheric pressure radio-frequency capacitive discharge with isolated electrodes

    International Nuclear Information System (INIS)

    Bazhenov, V.Yu.; Tsiolko, V.V.; Piun, V.M.; Chaplinskiy, R.Yu.; Kuzmichev, A.I.

    2013-01-01

    Glow characteristics of capacitive radio frequency discharge with isolated electrodes in low-current α and highcurrent gamma modes are determined experimentally. It is shown that transition from α mode to gamma mode occurs through a phase of coexistence of both modes in different parts of the discharge gap.

  5. Gas-discharge sources with charged particle emission from the plasma of glow discharge with a hollow cathode

    CERN Document Server

    Semenov, A P

    2001-01-01

    One studied properties of a magnetron discharge with a cold hollow and uncooled rod cathodes. One demonstrated the dominant effect of thermoelectron emission of a rod cathode heated in a discharge on characteristics of discharge and on emission properties of a gas-discharge plasma and the possibility pf a smooth transition of glow discharge to diffusion mode of arc discharge combustion. Paper describes sources of ions and electrons with improved physical and generalized design and engineering parameters. One shows the promise of the electrode structure of a hollow cathode magnetron discharge to be used as a source, in particular, of the atomic hydrogen and of atom flow of a working rod cathode

  6. On the regime transitions during the formation of an atmospheric pressure dielectric barrier glow discharge

    International Nuclear Information System (INIS)

    Martens, T; Bogaerts, A; Brok, W J M; Van Dijk, J

    2009-01-01

    The atmospheric pressure dielectric barrier discharge in helium is a pulsed discharge in nature. If during the electrical current pulse a glow discharge is reached, then this pulse will last only a few microseconds in operating periods of sinusoidal voltage with lengths of about 10 to 100 μs. In this paper we demonstrate that right before a glow discharge is reached, the discharge very closely resembles the commonly assumed Townsend discharge structure, but actually contains some significant differing features and hence should not be considered as a Townsend discharge. In order to clarify this, we present calculation results of high time and space resolution of the pulse formation. The results indicate that indeed a maximum of ionization is formed at the anode, but that the level of ionization remains high and that the electric field at that time is significantly disturbed. Our results also show where this intermediate structure comes from. (fast track communication)

  7. Full spatial-field visualization of gas temperature in an air micro-glow discharge by calibrated Schlieren photography

    Science.gov (United States)

    Xiong, Qing; Xu, Le; Wang, Xia; Xiong, Lin; Huang, Qinghua; Chen, Qiang; Wang, Jingang; Peng, Wenxiong; Li, Jiarui

    2018-03-01

    Gas temperature is an important basic parameter for both fundamental research and applications of plasmas. In this work, efforts were made to visualize the full spatial field of gas temperature (T g) in a microdischarge with sharp T g gradients by a method of calibrated Schlieren (CS) photography. Compared to other two typical diagnostic approaches, optical emission spectroscopy (OES) and Rayleigh scattering, the proposed CS method exhibits the ability to capture the whole field of gas temperature using a single Schlieren image, even the discharge is of non-luminous zones like Faraday dark space (FDS). The image shows that the T g field in the studied micro-glow air discharge expands quickly with the increase of discharge currents, especially in the cathode region. The two-dimensional maps of gas temperature display a ‘W-shape’ with sharp gradients in both areas of negative and positive glows, slightly arched distributions in the positive column, and cooling zones in the FDS. The obtained T g fields show similar patterns to that of the discharge luminance. With an increase in discharge currents, more electric energy is dissipated by heating air gas and inducing constriction of the low-temperature FDS. Except in the vicinities of electrode boundaries, due to the interference from optical diffraction, the estimated gas temperature distributions are of acceptable accuracy, confirmed by the approaches of OES and UV Rayleigh scattering.

  8. Self-consistent model for pulsed direct-current N2 glow discharge

    International Nuclear Information System (INIS)

    Liu Chengsen

    2005-01-01

    A self-consistent analysis of a pulsed direct-current (DC) N 2 glow discharge is presented. The model is based on a numerical solution of the continuity equations for electron and ions coupled with Poisson's equation. The spatial-temporal variations of ionic and electronic densities and electric field are obtained. The electric field structure exhibits all the characteristic regions of a typical glow discharge (the cathode fall, the negative glow, and the positive column). Current-voltage characteristics of the discharge can be obtained from the model. The calculated current-voltage results using a constant secondary electron emission coefficient for the gas pressure 133.32 Pa are in reasonable agreement with experiment. (authors)

  9. Reduction of Cr(VI) in aqueous solution with DC diaphragm glow discharge

    International Nuclear Information System (INIS)

    Wang, Xiaoyan; Jin, Xinglong; Zhou, Minghua; Chen, Zhenhai; Deng, Kai

    2013-01-01

    This paper investigated the reduction of Cr(VI) in aqueous solution with direct current diaphragm glow discharge (DGD). The glow discharge sustained around the hole on a quartz tube which divided the electrolyte cell into two parts. The reduction efficiencies of Cr(VI) under different applied voltages, initial conductivities, hole diameters, hole numbers, initial pH values and initial concentrations were systematically studied. The results showed that the reduction efficiency of Cr(VI) increased with the increase of applied voltage, initial conductivity, hole diameter and hole number. The different initial pH values showed less effects on the reduction of Cr(VI). The reduction efficiency decreased with the increasing initial concentration. In addition, the simultaneous reduction of Cr(VI) and decolorization of acid orange (AO) with DGD were also fulfilled. Furthermore, the energy efficiency for Cr(VI) reduction with DGD was calculated and compared with those in photocatalysis and other glow discharge reactor

  10. Removal of the codeposited carbon layer using He-O glow discharge

    International Nuclear Information System (INIS)

    Kunz, C.L.; Causey, R.A.; Clift, M.; Wampler, W.R.; Cowgill, D.F.

    2007-01-01

    In this study we examine the combination of a He-O glow discharge with heating as a possible technique to remove deuterium from TFTR tiles. Samples were cut from a relatively large area containing a uniform codeposited layer of deuterium and carbon. Auger/SEM was used to generate micrographs of each of the samples. The samples were also examined using Rutherford backscattering to determine the near surface composition. Individual samples were then exposed to a He-O glow discharge while being heated. After the exposure, the samples were returned for Auger/SEM and RBS of the same areas examined prior to the exposure. Comparing the samples before and after exposure revealed that the amount of the codeposited layer removed was significantly less than 1 μm. Removal rates this low would suggest that He-O glow discharge with heating is insufficient to remove the thick layers predicted for ITER in a timely fashion

  11. Time effectiveness of capillary effect improvement of ramie fabrics processed by RF glow discharging

    International Nuclear Information System (INIS)

    Wang Zhiwen; Wei Weixing; He Yanhe; Zhao Yuanqing; Pan Liyiji; Li Xuemei; Shi Shaodui; Li Guangxin

    2010-01-01

    The time effectiveness of capillary effect improvement of ramie fabrics processed by RF glow discharging was studied. The ramie fabrics were processed in fulfilling with different gas (O 2 , N 2 , Ar) by different parameters (such as pressure,power and time) plasma. The capillary effect of the ramie fabrics processed by RF glow discharging was tested at different time. The results indicate that the capillary effect of ramie fabrics processed by RF glow discharging has been improved, the improvement of the capillary effect firstly decrease rapidly, then slowly, and become stable after 15 day, it indicate that improvement of the ramie fabrics capillary has good time effectiveness, and the plasma parameter for the best capillary effect improvement of ramie fabric is 100 W and 40 Pa processed 20 min by oxygen plasma. (authors)

  12. A study on the equivalent electric circuit simulation model of DBD streamer and glow alternate discharge

    International Nuclear Information System (INIS)

    Yao, J; Zhang, Z T; Xu, S J; Yu, Q X; Yu, Z; Zhao, J S

    2013-01-01

    This paper presents a dynamic simulating model of the dielectric barrier discharge (DBD), structured as an equivalent electric circuit of the streamer and glow discharge generated alternately in DBD. The main parameters of DBD have been established by means of analysing the structural characteristics of a single discharge cell. An electrical comprehensive Simulink /MATLAB model was developed in order to reveal the interaction of the adjacent two discharge cell. A series of simulations was carried out in order to estimate the key structural parameters that affect the alternate streamer and glow discharge mode. The comparison results of experimental and simulate indicate that there exists a close similarity of the current waveforms graphic. Therefore, we can grasp a deep understanding mechanism of the dielectric barrier discharge and optimize the plasma reactor.

  13. Binary and ternary gas mixtures for use in glow discharge closing switches

    Science.gov (United States)

    Hunter, S.R.; Christophorou, L.G.

    1988-04-27

    Highly efficient binary and ternary gas mixtures for use in diffuse glow discharge closing switches are disclosed. The binary mixtures are combinations of helium or neon and selected perfluorides. The ternary mixtures are combinations of helium, neon, or argon, a selected perfluoride, and a small amount of gas that exhibits enhanced ionization characteristics. These mixtures are shown to be the optimum choices for use in diffuse glow discharge closing switches by virtue if the combines physio-electric properties of the mixture components. 9 figs.

  14. Glow discharge processing vs bakeout for aluminum storage ring vacuum chambers

    International Nuclear Information System (INIS)

    Dean, N.R.; Hoyt, E.W.; Palrang, M.T.; Walker, B.G.

    1977-11-01

    Experiments were carried out on laboratory and prototype scale systems in order to establish the feasibility of argon discharge processing the PEP storage ring aluminum vacuum chambers. Electron-induced desorption rates showed significant reductions following bakeout and/or argon glow discharge treatment (>10 19 ions cm -1 ). Data are presented and discussed in relation to advantages and problems associated with: water removal, argon trapping and subsequent release, electron energy dependence, discharge distribution, and surface plasma chemical effects

  15. Binary and ternary gas mixtures with temperature enhanced diffuse glow discharge characteristics for use in closing switches

    Science.gov (United States)

    Christophorou, L.G.; Hunter, S.R.

    1990-06-26

    An improvement to the gas mixture used in diffuse glow discharge closing switches is disclosed which includes binary and ternary gas mixtures which are formulated to exhibit decreasing electron attachment with increasing temperature. This increases the efficiency of the conductance of the glow discharge and further inhibits the formation of an arc. 11 figs.

  16. Effects of discharge parameters on the micro-hollow cathode sustained glow discharge

    Science.gov (United States)

    Shoujie, HE; Peng, WANG; Jing, HA; Baoming, ZHANG; Zhao, ZHANG; Qing, LI

    2018-05-01

    The effects of parameters such as pressure, first anode radius, and the cavity diameter on the micro-hollow cathode sustained glow discharge are investigated by using a two-dimensional self-consistent fluid model in pure argon. The results indicate that the three parameters influence the discharge in the regions inside and outside of the cavity. Under a fixed voltage on each electrode, a larger volume of high density plasma can be produced in the region between the first and the second anodes by selecting the appropriate pressure, the higher first anode, and the appropriate cavity diameter. As the pressure increases, the electron density inside the hollow cathode, the high density plasma volume between the first anode and second anodes, and the radial electric field in the cathode cavity initially increase and subsequently decrease. As the cavity diameter increases, the high-density plasma volume between the first and second anodes initially increases and subsequently decreases; whereas the electron density inside the hollow cathode decreases. As the first anode radius increases, the electron density increases both inside and outside of the cavity. Moreover, the increase of the electron density is more obvious in the microcathode sustained region than in the micro cavity region. The results reveal that the discharge inside the cavity interacts with that outside the cavity. The strong hollow cathode effect and the high-density plasma inside the cavity favor the formation of a sustained discharge between the first anode and the second anodes. Results also show that the radial boundary conditions exert a considerably weaker influence on the discharge except for a little change in the region close to the radial boundary.

  17. The experience with JET's combined dc/Rf glow discharge cleaning (GDC) system

    International Nuclear Information System (INIS)

    Pearce, R.J.H.; Andrew, P.; Bryan, S.

    1996-01-01

    The JET Tokamak was fitted with four new electrodes of novel design, each powered from individual computer controlled dc and RF supplies. Details of enhancements and problems from 15 months experience with the system are outlined. Experiments were performed to assess the effect of RF on the glow discharge characteristics, and to establish stable glow at low pressure and high voltage. JET combined RF/dc glow discharge cleaning (GDC) had no significant advantages over pure dc GDC, provided highly stable dc current control was obtained. In fact, the mechanically weak electrode inductor spiral required to allow RF posed a distinct disadvantage. The electrodes were converted to simple plates, following damage caused by halo currents during Tokamak plasma disruptions. The performance of these electrodes was assessed. Future developments in the JET GDC system are outlined. (Author)

  18. Fluid model of dc glow discharge with nonlocal ionization source term

    International Nuclear Information System (INIS)

    Rafatov, I R; Bogdanov, E A; Kudryavtsev, A A

    2012-01-01

    We developed and tested a simple hybrid model for a glow discharge, which incorporates nonlocal ionization by fast electrons into the fluid framework. Calculations have been performed for an argon gas. Comparison with the experimental data as well as with the hybrid (particle) and fluid modelling results demonstated good applicability of the proposed model.

  19. Gas phase hydrogen peroxide production in atmospheric pressure glow discharges operating in He - H2O

    NARCIS (Netherlands)

    Vasko, C.A.; Veldhuizen, van E.M.; Bruggeman, P.J.

    2013-01-01

    The gas phase production of hydrogen peroxide (H2O2) in a RF atmospheric pressure glow discharge with helium and water vapour has been investigated as a function of the gas flow. It is shown that the production of H2O2 is through the recombination of two OH radicals in a three body collision and the

  20. Anode pattern formation in atmospheric pressure air glow discharges with water anode

    NARCIS (Netherlands)

    Verreycken, T.; Bruggeman, P.J.; Leys, C.

    2009-01-01

    Pattern formation in the anode layer at a water electrode in atmospheric pressure glow discharges in air is studied. With increasing current a sequence of different anode spot structures occurs from a constricted homogeneous spot in the case of small currents to a pattern consisting of small

  1. Source of high-voltage power supply for ozone generators at glow discharge

    International Nuclear Information System (INIS)

    Bruev, A.A.; Golota, V.I.; Zavada, L.M.; Taran, G.V.

    2000-01-01

    High-voltage power supply source on quasi-resonance inverter base which works at direct current regime is described. This source forms 20 kV voltage with 0 - 10 mA current regulation. It protects the source from current break-downs and feeds ozone generators at glow discharge

  2. Low-pressure glow discharges with oscillating electrons in different electrode systems

    International Nuclear Information System (INIS)

    Bersenev, V.V.; Gavriolv, N.V.; Nikulin, S.P.

    1995-01-01

    One of the main applications of low - pressure glow discharges is the development on their basis of charged - particle beam sources. The use of glow discharges with oscillating electrons, which can operate stably in the voltage and pressure range to the left of the left branch of Pashen's curve, shows promise, because the decrease in critical pressure p 0 , below which the discharge operation becomes impossible, in the discharge system of a source promotes an increase in the electrical strength of its accelerating system. This, in its turn, makes possible the expansion of the operation range of accelerating voltages. This experimental investigation of glow discharges in such well - known systems with oscillating electrons, as Hollow Cathode (HC), Penning's System (PS) and Inverse Magnetron (IM), is aimed at revealing the system operating at the lowest pressure. Besides, both common features and peculiarities of discharge operation in these systems are discussed. Though there is an extensive amount of published information covering all the specified discharges, the carrying out of such investigation is justified, since a comparative analysis of results obtained by different authors is hampered by various conditions of their experiments

  3. Atomic iodine production in a gas flow by decomposing methyl iodide in a dc glow discharge

    International Nuclear Information System (INIS)

    Mikheyev, P A; Shepelenko, A A; Voronov, A I; Kupryaev, Nikolai V

    2002-01-01

    The production of atomic iodine for an oxygen - iodine laser is studied by decomposing methyl iodide in a dc glow discharge in a vortex gas flow. The concentration of iodine atoms in discharge products was measured from the atomic iodine absorption of the radiation of a single-frequency tunable diode laser at a wavelength of 1.315 μm. Atomic iodine concentrations sufficient for the operation of an oxygen - iodine laser were obtained. The concentration of atomic iodine amounted to 3.6 x 10 15 cm -3 for a pressure of the carrying argon gas of 15 Torr. The discharge stabilisation by a vortex gas flow allowed the glow discharge to be sustained in a strongly electronegative halogen-containing gas mixture for pressures up to 20 Torr. (active media)

  4. Photo-preionization stabilized high-pressure glow-discharge lasers

    International Nuclear Information System (INIS)

    Von Bergmann, H.M.

    1980-07-01

    Simple nanosecond stabilization and pulsing techniques were developed to excite high-pressure gas-discharge lasers at high overvoltages and high specific power loadings. The techniques were applied to a variety of ultraviolet and visible laser systems employing fast transmission line pulsers and conventional LC generators. The stabilization procedures are evaluated and the parameters which control the geometry and uniformity of the high-pressure glow discharges are investigated. A detailed study of the formation, distribution and spectral characteristics of the fast surface corona discharges is provided. The stabilization and pulsing techniques were used for the corona and glow discharge excitation of high-pressure ultraviolet N 2 lasers. A detailed spectrally- and temporally-resolved study of the gain, fluorescence and energy extraction characteristics of the atmospheric pressure N 2 plasmas is provided

  5. Studies on the Electrical Characteristics of a DC Glow Discharge by Using Langmuir Probe

    International Nuclear Information System (INIS)

    Safaai, S. S.; Yap, S. L.; Wong, C. S.; Muniandy, S. V.; Smith, P. W.

    2010-01-01

    Electrical characteristics of a DC glow discharge are studied with the aim of determining the suitable parameters for stable operation of the dusty plasma system. The presence of dust particles in plasma significantly alters the charged particle equilibrium in the plasma and leads to various phenomena. Argon plasma produced by DC glow discharge is investigated with a further goal of studying dusty plasma phenomena. The discharge system has two disc-shaped parallel plate electrodes. The electrodes are enclosed in a large cylindrical stainless steel chamber filled with argon gas. Two important physical parameters affecting the condition of the discharge are the gas pressure and the inter-electrode distance. A single Langmuir probe based on the Keithley source meter is used to determine the electron temperature of the positive column. A custom designed probe is employed to determine the potential distribution between the electrodes during the discharge. The I-V characteristic curve and the Langmuir probe measurement are then used to determine the electron energy distribution of the glow discharge plasma.

  6. Methane Conversion to C2 Hydrocarbons by Abnormal Glow Discharge at Atmospheric Pressure

    International Nuclear Information System (INIS)

    Dai Wei; Yu Hui; Chen Qi; Yin Yongxiang; Dai Xiaoyan

    2005-01-01

    Methane conversion to C 2 hydrocarbons has been investigated with the addition of hydrogen in a plasma reactor of abnormal glow discharge at atmospheric pressure. The aim of this experiment is to minimize coke formation and improve discharge stability. The typical conditions in the experiment are 300 ml of total feed flux and 400 W of discharge power. The experimental results show that methane conversion is from 91.6% to 35.2% in mol, acetylene selectivity is from 90.2% to 57.6%, and ethylene selectivity is approximately from 7.8% to 3.6%, where the coke increases gradually along with the increase of CH 4 /H 2 from 2: 8 to 9: 1. A stable discharge for a considerable running time can be obtained only at a lower ratio of CH 4 /H 2 2: 8 or 3: 7. These phenomena indicate that the coke deposition during methane conversion is obviously reduced by adding a large amount of hydrogen during an abnormal glow discharge. A qualitative interpretation is presented, namely, with abundant hydrogen, the possibility that hydrogen molecules are activated to hydrogen radicals is increased with the help of the abnormal glow discharge. These hydrogen radicals react with carbon radicals to form C 2 hydrocarbon products. Therefore, the deposition of coke is restrained

  7. Study of the striated nature of a glow discharge

    International Nuclear Information System (INIS)

    Hernandez A, M.

    1995-01-01

    In an investigation in progress here, plasma diagnostics and detection of standing and moving striations is being made in a discharge in Argon at pressures of 2 x 10 -1 to 9 x 10 -1 mb and currents of 2 to 9 m-amp inside an discharge tube. Measurement of the temperature of the electrons, the concentration of electrons and the plasma potential are obtained in different places of the discharge by the double probe method, together with the computation system reported in [1]. In similar way an experimental work of the striated column in a discharge plasma to find the regimen of appearance of the standing and moving striations show some properties of moving striations (frequency and velocity) and standing striations. Two different oscilations are observed in motion in contrary directions along the discharge tube with a photomultiplier. (Author)

  8. Elimination of inter-discharge helium glow discharge cleaning with lithium evaporation in NSTX

    Directory of Open Access Journals (Sweden)

    R. Maingi

    2017-08-01

    Full Text Available Operation in the National Spherical Torus Experiment (NSTX typically used either periodic boronization and inter-shot helium glow discharge cleaning (HeGDC, or inter-shot lithium evaporation without boronization, and initially with inter-shot HeGDC. To assess the viability of operation without HeGDC, dedicated experiments were conducted in which Li evaporation was used while systematically shrinking the HeGDC between shots from the standard 10min to zero (10→6.5→4→0. Good shot reproducibility without HeGDC was achieved with lithium evaporations of 100mg or higher; evaporations of 200–300mg typically resulted in very low ELM frequency or ELM-free operation, reduced wall fueling, and improved energy confinement. The use of HeGDC before lithium evaporation modestly reduced Dα in the outer scrape-off layer, but not at the strike point. Pedestal electron and ion temperature also improved modestly, suggesting that HeGDC prior to lithium evaporation is a useful tool for experiments that seek to maximize plasma performance.

  9. Influence of an electric probe on the anode layer of a glow discharge in nitrogen

    Science.gov (United States)

    Taran, M. D.; Dyatko, N. A.; Kochetov, I. V.; Napartovich, A. P.; Akishev, Yu S.

    2018-05-01

    A two-dimensional (2D) numerical model of a DC glow discharge in nitrogen is developed for the case when the electric probe is mounted in the discharge gap. Within this model, calculations are performed for the gas pressure of 50 Torr and discharge current densities of 22 and 90 mA cm‑2. A cylindrical probe 1 mm in diameter is located parallel to the anode at a distance of 5 or 10 mm. The probe potential is varied in a wide range relative to the floating potential. Numerical simulations predict the 2D plasma perturbation pattern induced by the electric probe and the influence of the probe on anode layer characteristics. In particular, conditions are determined under which a region with no glow forms in the anode layer.

  10. Radiofrequency glow discharge time of flight mass spectrometry: pulsed vs. continuous mode

    International Nuclear Information System (INIS)

    Lobo, L.; Pereiro, R.; Sanz-Medel, A.; Bordel, N.; Tempez, A.; Chapon, P.; Hohl, M.; Michler, J.

    2009-01-01

    Full text: Glow discharge (GD) is a well established tool for the direct analysis of solids. The application field of the original direct current GD, restricted to conductive samples, has been extended by radiofrequency powered GDs that can be applied for conductive and non-conductive samples. Moreover, the introduction of pulsed GD has opened the possibility of applying higher instantaneous powers that can improve the atomization-ionization processes and therefore the sensitivity. Furthermore, pulsed-GD may enable temporal separation of discharge gas species from the sample ions. In this work the analytical performances of radiofrequency and pulsed radiofrequency glow discharges are evaluated by using a time of flight mass analyzer (TOFMS). (author)

  11. Particle control in DIII-D with helium glow discharge conditioning

    International Nuclear Information System (INIS)

    Jackson, G.L.; Taylor, T.S.; Taylor, P.L.

    1990-01-01

    Helium glow discharge conditioning of DIII-D is routinely used before every tokamak discharge to desorb hydrogen from the graphite tiles, which are the plasma facing surfaces for the floor, inner wall and top of the vessel. In addition to reducing hydrogen fuelling of the plasma by the graphite surfaces, helium glow discharges are also effective in removing low-Z impurities, primarily in the form of carbon monoxide and hydrocarbons, and this has permitted higher current divertor operation and more rapid recovery from tokamak disruptions. Since the implementation of repetitive helium glow wall conditioning, the parameter space in which tokamak discharges in DIII-D can be obtained has been expanded to include the first observations of limiter H-mode confinement, the Ohmic H-mode with periods of up to 150 ms that are free of edge localized modes, more reliable low q operation with volume averaged beta of up to 9.3%, improved control over locked modes and plasma discharges at lower electron density. (author). 37 refs, 12 figs, 1 tab

  12. Transitions between corona, glow, and spark regimes of nanosecond repetitively pulsed discharges in air at atmospheric pressure

    OpenAIRE

    Pai , David ,; Lacoste , Deanna ,; Laux , C.

    2010-01-01

    International audience; In atmospheric pressure air preheated from 300 to 1000 K, the nanosecond repetitively pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and interelectrode gap distance) of each discharge regime. In particular, the experimental conditions necessary for the glow regime of NRP discharges have been determine...

  13. Glow-discharge-created electron beams and beam-excited lasers

    International Nuclear Information System (INIS)

    Meyer, J.D.

    1989-01-01

    Efficiently created glow discharge electron beams have been developed and studied in detail. The beam mode of operation occurs in the abnormal glow adjacent to the glow-to-arc transition regime. In contrast to electron beams generated in high vacuum from thermionic electron emitting sources, this type of discharge creates electrons directly in soft vacuum by secondary electron emission from cold cathode surfaces following the bombardment of the cathode surface by fast ions and neutral atoms. Factors influencing the efficient electron emission from cold cathodes are presented with emphasis on cathode materials. Sintered ceramic-metal cathodes and oxide-coated cathodes are presented, both of which can produce high power, efficiently generated, d.c. electron beams with discharge currents up to 1 amp (∼130 mA/cm 2 ) at volt ages of up to 6 kV. Novel cathode designs and discharge geometries are presented with specific emphasis on both self-focussed beams emitted from circular cathodes and line-source electron beams emitted from rectangular cathodes forming a thin sheet of electrons. Electrostatically focussed line-source electron beams are spatially characterized by experimentally measuring the effect of discharge parameters and cathode design upon the focussed beam width, focal point, and uniformity. This is achieved by scanning a current collecting detector in three dimensions in order to profile the distribution of electron beam current. Discharge electron beams are further characterized by their electron energy distribution. Measured electron flux energy distributions of transmitted beam electrons in the negative glow are compared to theoretical models. The relative effects of elastic and inelastic collisions mechanisms upon both the overall form and detailed structure of the energy distribution are discussed

  14. Liquid sampling-atmospheric pressure glow discharge as a secondary excitation source: Assessment of plasma characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Manard, Benjamin T. [Department of Chemistry, Clemson University, Clemson, SC 29634 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Gonzalez, Jhanis J. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Sarkar, Arnab [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Dong, Meirong; Chirinos, Jose; Mao, Xianglei; Russo, Richard E. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Marcus, R. Kenneth [Department of Chemistry, Clemson University, Clemson, SC 29634 (United States)

    2014-04-01

    The liquid sampling-atmospheric pressure glow discharge (LS-APGD) has been assessed as a secondary excitation source with a parametric evaluation regarding carrier gas flow rate, applied current, and electrode distance. With this parametric evaluation, plasma optical emission was monitored in order to obtain a fundamental understanding with regards to rotational temperature (T{sub rot}), excitation temperature (T{sub exc}), electron number density (n{sub e}), and plasma robustness. Incentive for these studies is not only for a greater overall fundamental knowledge of the APGD, but also in instrumenting a secondary excitation/ionization source following laser ablation (LA). Rotational temperatures were determined through experimentally fitting of the N{sub 2} and OH molecular emission bands while atomic excitation temperatures were calculated using a Boltzmann distribution of He and Mg atomic lines. The rotational and excitation temperatures were determined to be ∼ 1000 K and ∼ 2700 K respectively. Electron number density was calculated to be on the order of ∼ 3 × 10{sup 15} cm{sup −3} utilizing Stark broadening effects of the Hα line of the Balmer series and a He I transition. In addition, those diagnostics were performed introducing magnesium (by solution feed and laser ablation) into the plasma in order to determine any perturbation under heavy matrix sampling. The so-called plasma robustness factor, derived by monitoring Mg II/Mg I emission ratios, is also employed as a reflection of potential perturbations in microplasma energetics across the various operation conditions and sample loadings. While truly a miniaturized source (< 1 mm{sup 3} volume), the LS-APGD is shown to be quite robust with plasma characteristics and temperatures being unaffected upon introduction of metal species, whether by liquid or laser ablation sample introduction. - Highlights: • Liquid sampling-atmospheric pressure glow discharge (LS-APGD) • LS-APGD as a secondary

  15. Liquid sampling-atmospheric pressure glow discharge as a secondary excitation source: Assessment of plasma characteristics

    International Nuclear Information System (INIS)

    Manard, Benjamin T.; Gonzalez, Jhanis J.; Sarkar, Arnab; Dong, Meirong; Chirinos, Jose; Mao, Xianglei; Russo, Richard E.; Marcus, R. Kenneth

    2014-01-01

    The liquid sampling-atmospheric pressure glow discharge (LS-APGD) has been assessed as a secondary excitation source with a parametric evaluation regarding carrier gas flow rate, applied current, and electrode distance. With this parametric evaluation, plasma optical emission was monitored in order to obtain a fundamental understanding with regards to rotational temperature (T rot ), excitation temperature (T exc ), electron number density (n e ), and plasma robustness. Incentive for these studies is not only for a greater overall fundamental knowledge of the APGD, but also in instrumenting a secondary excitation/ionization source following laser ablation (LA). Rotational temperatures were determined through experimentally fitting of the N 2 and OH molecular emission bands while atomic excitation temperatures were calculated using a Boltzmann distribution of He and Mg atomic lines. The rotational and excitation temperatures were determined to be ∼ 1000 K and ∼ 2700 K respectively. Electron number density was calculated to be on the order of ∼ 3 × 10 15 cm −3 utilizing Stark broadening effects of the Hα line of the Balmer series and a He I transition. In addition, those diagnostics were performed introducing magnesium (by solution feed and laser ablation) into the plasma in order to determine any perturbation under heavy matrix sampling. The so-called plasma robustness factor, derived by monitoring Mg II/Mg I emission ratios, is also employed as a reflection of potential perturbations in microplasma energetics across the various operation conditions and sample loadings. While truly a miniaturized source ( 3 volume), the LS-APGD is shown to be quite robust with plasma characteristics and temperatures being unaffected upon introduction of metal species, whether by liquid or laser ablation sample introduction. - Highlights: • Liquid sampling-atmospheric pressure glow discharge (LS-APGD) • LS-APGD as a secondary excitation source for laser-ablated (LA

  16. Liquid sampling-atmospheric pressure glow discharge as a secondary excitation source: Assessment of plasma characteristics

    Science.gov (United States)

    Manard, Benjamin T.; Gonzalez, Jhanis J.; Sarkar, Arnab; Dong, Meirong; Chirinos, Jose; Mao, Xianglei; Russo, Richard E.; Marcus, R. Kenneth

    The liquid sampling-atmospheric pressure glow discharge (LS-APGD) has been assessed as a secondary excitation source with a parametric evaluation regarding carrier gas flow rate, applied current, and electrode distance. With this parametric evaluation, plasma optical emission was monitored in order to obtain a fundamental understanding with regards to rotational temperature (Trot), excitation temperature (Texc), electron number density (ne), and plasma robustness. Incentive for these studies is not only for a greater overall fundamental knowledge of the APGD, but also in instrumenting a secondary excitation/ionization source following laser ablation (LA). Rotational temperatures were determined through experimentally fitting of the N2 and OH molecular emission bands while atomic excitation temperatures were calculated using a Boltzmann distribution of He and Mg atomic lines. The rotational and excitation temperatures were determined to be ~ 1000 K and ~ 2700 K respectively. Electron number density was calculated to be on the order of ~ 3 × 1015 cm- 3 utilizing Stark broadening effects of the Hα line of the Balmer series and a He I transition. In addition, those diagnostics were performed introducing magnesium (by solution feed and laser ablation) into the plasma in order to determine any perturbation under heavy matrix sampling. The so-called plasma robustness factor, derived by monitoring Mg II/Mg I emission ratios, is also employed as a reflection of potential perturbations in microplasma energetics across the various operation conditions and sample loadings. While truly a miniaturized source (laser ablation sample introduction.

  17. Study on the characteristics of hysteresis loop and resistance of glow discharge plasma using argon gas

    Science.gov (United States)

    Mathew, Prijil; Sajith Mathews, T.; Kurian, P. J.; Chattopadyay, P. K.

    2018-05-01

    Hysteresis in discharge current is produced in a low-pressure, magnetic field free, Glow discharge plasma by varying discharge voltage. The variation in area of the hysteresis loops with pressure, electrode distance and load resistor studied. To understand, the nonlinear behaviour of the I-V characteristics, the changes in gas resistance with electrode voltage, pressure and load resistor were studied. After many trials we propose the best suitable empirical equation for the exponential decrease of the gas resistance with electrode voltage as; R = Rmin + Ae-0.008V, which is a novel one and matches well with our experimental results.

  18. Electric field strength in a Xe-Ne glow discharge

    NARCIS (Netherlands)

    Visser, B.; Hayashi, D.; Kroesen, G.M.W.; Stoffels, W.W.

    2001-01-01

    Many applications of plasma physics are related to light generation. The applications range from TL-tubes until the latest flat displays. The size of discharges is decreasing further and further. At this moment the typical dimensions of a plasma display panel cell are in the order of 100 µm. A model

  19. Setting-up of the Laser Induced Fluorescence diagnostic. Measurements of Cr density in a neon glow discharge; Puesta a punto del diagnstico de fluorescencia inducida por laser. Medidas de densidad de Cr en Glow discharg de Neon

    Energy Technology Data Exchange (ETDEWEB)

    Tafalla, D.; Cal, E. de la; Tabares, F. L.

    1994-07-01

    A plasma diagnostic based on the Laser Induced Fluorescence (LIF) technique has been set up in the Fusion Division at the CIEMAT. In a preliminary experiment, the density of sputtered chromium atoms produced in a neon glow discharge was measured. Firstly, the laser beam was characterized by calibration of its wavelength, bandwidth and energy profile and Rayleigh scattering in N2 was used for the optical system calibration. An absolute density of Cr atoms of n {approx} 5x10 cm was obtained in discharges at 100 mA and pressure of 15 mTorr and a linear dependence of the LIF signal us. current was found. These values are in agreement with those expected from the tabulated sputtering yields and the thermalization and diffusion of the sputtered atoms into the Ne plasma. (Author) 19 refs.

  20. Electrical Characterization of an RF Glow Discharge at Room Pressure

    International Nuclear Information System (INIS)

    Perez-Martinez, J. A.; Piedad-Beneitez, A. de la; Pena-Eguiluz, R.; Mercado-Cabrera, A.; Valencia A, R.; Barocio, S. R.; Lopez-Callejas, R.; Godoy-Cabrera, O. G.; Benitez-Read, J. S.; Pacheco-Sotelo, J. O.

    2006-01-01

    A non-thermal atmospheric-like plasma source able to operate at room temperature represents, by its physical nature, a considerable potential for biological applications, given its highly accurate action and extremely controllable penetration on the surface of biological tissue. As we start up a research line into this technology, we report the electrical characterization of a room pressure plasma discharge by means of a coupling network model. The discharge is produced by a 13.56MHz commercial generator. As it is impossible to measure directly its state variables (voltage and current intensity) due to the considerable perturbation created by introducing a low impedance at the system output, then an indirect estimation of such variables is achieved from experimental diagnostics at the input, so to validate the proposed electrical model

  1. Debinding of injected parts using an abnormal glow discharge

    International Nuclear Information System (INIS)

    Santos, M.A.; Maliska, A.M.; Klein, A.N.; Ristow, W.; Muzart, J.L.R.

    2005-01-01

    Results of binder removal of injected PM components using plasma technology are presented. The samples were injected with 55.18 vol.% of iron powder, 23.57 vol.% of paraffin and 21.25 vol.%. of polypropylene and treated in hydrogen and argon discharges at a pressure of 400 Pa (3 Torr), varying temperature and treatment times. The discharge was generated by a pulsed power source in a confined anode-cathode geometry. The outer electrode consisted of the cathode and was heated by the bombardment of ions accelerated in the cathode region. The sample was placed on an inner holder and heated by thermal radiation. Three different configurations of electrodes were used in order to evaluate the influence of electron bombardment on the sample surface, the interaction of the reactive species generated in the discharge with the binder and thermal effects on the dissociation of the organic molecules. Samples were characterized by mass loss and energy dispersive X-ray (EDX) analysis. The results show that the electron bombardment added to the interaction of reactive species on the sample surface significantly activated the binder removal. By using a laboratory scale plasma reactor, it was shown that the binder extraction and pre-sintering cycle could be performed in a single thermal cycle lasting approximately 200 min

  2. Microelectrode-assisted low-voltage atmospheric pressure glow discharge in air

    Science.gov (United States)

    Liu, Wenzheng; Zhao, Shuai; Niu, Jiangqi; Chai, Maolin

    2017-09-01

    During the process of discharge, appropriately changing the paths corresponding to electric field lines and the field strength distribution along these paths, as well as increasing the number of initial electrons, can effectively enhance the uniformity of discharge and inhibit the formation of filamentary discharge. A method is proposed that uses a microelectrode to initiate the macroscopic discharge phenomenon. An asymmetric structure was designed comprising a single electrode of carbon fiber; this electrode structure is of helical-contact type. Benefitting from the special electric field distribution and the microdischarge process, a three-dimensional atmospheric pressure glow discharge was achieved in air, characterized by low discharge voltage, low energy consumption, good diffusion performance, and less ozone generation. The plasma studied is uniform and stable with good diffusion characteristics and low levels of contaminants and hence has potential applications in the field of air purification.

  3. COATING AND MANDREL EFFECTS ON FABRICATION OF GLOW DISCHARGE POLYMER NIF SCALE INDIRECT DRIVE CAPSULES

    International Nuclear Information System (INIS)

    NIKROO, A.; PONTELANDOLFO, J.M.; CASTILLO, E.R.

    2002-01-01

    OAK A271 COATING AND MANDREL EFFECTS ON FABRICATION OF GLOW DISCHARGE POLYMER NIF SCALE INDIRECT DRIVE CAPSULES. Targets for the National Ignition Facility (NIF) need to be about 200 (micro)m thick and 2 mm in diameter. These dimensions are well beyond those currently fabricated on a routine basis. They have investigated fabrication of near NIF scale targets using the depolymerizable mandrel technique. Poly-alpha-methylstyrene (PAMS) mandrels, about 2 mm in diameter, of varying qualities were coated with as much as 125 (micro)m of glow discharge polymer (GDP). The surface finish of the final shells was examined using a variety of techniques. A clear dependence of the modal spectrum of final GDP shell on the quality of the initial PAMS mandrels was observed. isolated features were found to be the greatest cause for a shell not meeting the NIF standard

  4. Direct measurements of particle transport in dc glow discharge dusty plasmas

    International Nuclear Information System (INIS)

    Thomas, E. Jr.

    2001-01-01

    Many recent experiments in dc glow discharge plasmas have shown that clouds of dust particles can be suspended near the biased electrodes. Once formed, the dust clouds have well defined boundaries while particle motion within the clouds can be quite complex. Because the dust particles in the cloud can remain suspended in the plasma for tens of minutes, it implies that the particles have a low diffusive loss rate and follow closed trajectories within the cloud. In the experiments discussed in this paper, direct measurements of the dust particle velocities are made using particle image velocimetry (PIV) techniques. From the velocity measurements, a reconstruction of the three-dimensional transport of the dust particles is performed. A qualitative model is developed for the closed motion of the dust particles in a dc glow discharge dusty plasma. (orig.)

  5. Electrostatic analyzer for electron and ion energy in glow discharge tube

    International Nuclear Information System (INIS)

    Bong Kil Yeon.

    1984-01-01

    The project, the construction and use of an electrostatic energy analyser (Faraday Cup) are described explaining physically its working mechanism. The analyser was used in a glow discharge tube with air and an air-argon mixture. A chapter with the theory of the glow discharge is included. The ion and electron temperatures, the plasma potential and the distribution function for ions and electrons were measured. The electron temperature and plasma potential were also measured using a Langmuir probe and the results show reasonable agreement with the results of the analyser. Good fits of the experimental electron and ion distribution functions were obtained with Maxwellian distributions centered values near the plasma potential. Finally, we discuss the performance of the analyser compared to Langmuir probes. (author) [pt

  6. Analysis of the different zones of glow discharge of ethyl alcohol (C2H6O)

    International Nuclear Information System (INIS)

    Torres, C; Reyes, P G; Mulia, J; Castillo, F; Martínez, H

    2014-01-01

    The aim of this work is to explore the emission spectroscopy of ethyl alcohol in some regions, also is determine the result elements of the glow discharge, the spectrums were observed in a range of 200 at 1100 nm in the different zones inside of the tube at different distances of 20 and 30 cm. The elements are: in anode region C 6 H 5 (483.02 nm), CHO (519.56 nm) and H 2 (560.47 nm), in the positive column CO 2 + (315.52 y 337.00 nm), O + (357.48 nm), CH + (380.61 nm) and CO + (399.73 nm); in the cathode region we observed O + (391.19 nm), CHOCHO (428.00 nm), CO + (471.12 nm) and H 2 (656.52 nm). C 6 H 5 , CHO y H 2 species occurring in all regions analyzed varying the glow discharge emission intensity.

  7. Clostridium beijerinckii mutant obtained atmospheric pressure glow discharge generates enhanced electricity in a microbial fuel cell.

    Science.gov (United States)

    Liu, Jun; Guo, Ting; Wang, Dong; Ying, Hanjie

    2015-01-01

    A Clostridium beijerinckii mutant M13 was derived from C. beijerinckii NCIMB 8052 by atmospheric pressure glow discharge. C. beijerinckii M13 generated a maximum output power density of 79.2 mW m(-2) and a maximum output voltage of 230 mV in a microbial fuel cell containing 1 g glucose l(-1) as carbon source and 0.15 g methyl viologen l(-1) as an electron carrier.

  8. Cathode fall parameters of a self-sustained normal glow discharge in atmospheric-pressure helium

    International Nuclear Information System (INIS)

    Arkhipenko, V.I.; Zgirovskii, S.M.; Kirillov, A.A.; Simonchik, L.V.

    2002-01-01

    Results from comprehensive studies of a high-current self-sustained glow discharge in atmospheric-pressure helium are presented. The main parameters of the cathode fall, namely, the electric field profile, cathode fall thickness, current density, gas temperature, and heat flux to the cathode are determined. The results obtained are discussed using one-dimensional models of the cathode fall with allowance for volumetric heat release

  9. Hardening of alloys in glow discharge with the use of pulsed electric current

    International Nuclear Information System (INIS)

    Shipko, M.N.; Pomel'nikova, A.S.; Solunin, A.M.; Solunin, M.A.

    2002-01-01

    The effect of ex/ternal pulsed electric field on the thickness of a hardened surface layer of a Nd-Fe-B system alloy during chemical heat treatment in a glow discharge is studied. The relationship is established between the hardened layer thickness and the frequency of external electric field which is verified by derived equations for the relation between electron energy and pulsed electric field frequency [ru

  10. Use of Helium Production to Screen Glow Discharges for Low Energy Nuclear Reactions (LENR)

    Science.gov (United States)

    Passell, Thomas O.

    2011-03-01

    My working hypothesis of the conditions required to observe low energy nuclear reactions (LENR) follows: 1) High fluxes of deuterium atoms through interfaces of grains of metals that readily accommodate movement of hydrogen atoms interstitially is the driving variable that produces the widely observed episodes of excess heat above the total of all input energy. 2) This deuterium atom flux has been most often achieved at high electrochemical current densities on highly deuterium-loaded palladium cathodes but is clearly possible in other experimental arrangements in which the metal is interfacing gaseous deuterium, as in an electrical glow discharge. 3) Since the excess heat episodes must be producing the product(s) of some nuclear fusion reaction(s) screening of options may be easier with measurement of those ``ashes'' than the observance of the excess heat. 4) All but a few of the exothermic fusion reactions known among the first 5 elements produce He-4. Hence helium-4 appearance in an experiment may be the most efficient indicator of some fusion reaction without commitment on which reaction is occurring. This set of hypotheses led me to produce a series of sealed tubes of wire electrodes of metals known to absorb hydrogen and operate them for 100 days at the 1 watt power level using deuterium gas pressures of ~ 100 torr powered by 40 Khz AC power supplies. Observation of helium will be by measurement of helium optical emission lines through the glass envelope surrounding the discharge. The results of the first 18 months of this effort will be described.

  11. Setting-up of the Laser Induced Fluorescence diagnostic. Measurements of Cr density in a neon glow discharge

    International Nuclear Information System (INIS)

    Tafalla, D.; Cal, E. de la; Tabares, F. L.

    1994-01-01

    A plasma diagnostic based on the Laser Induced Fluorescence (LIF) technique has been set up in the Fusion Division at the CIEMAT. In a preliminary experiment, the density of sputtered chromium atoms produced in a neon glow discharge was measured. Firstly, the laser beam was characterized by calibration of its wavelength, bandwidth and energy profile and Rayleigh scattering in N2 was used for the optical system calibration. An absolute density of Cr atoms of n ∼ 5x10 cm was obtained in discharges at 100 mA and pressure of 15 mTorr and a linear dependence of the LIF signal us. current was found. These values are in agreement with those expected from the tabulated sputtering yields and the thermalization and diffusion of the sputtered atoms into the Ne plasma. (Author) 19 refs

  12. Setting-up of the Laser Induced Fluorescence diagnostic. Measurements of Cr density in a neon glow discharge

    International Nuclear Information System (INIS)

    Tafalla, D.; Cal, E. de la; Tabares, F.L.

    1994-01-01

    A plasma diagnostic based on the Laser Induced Fluorescence (LIF) technique has been set up in the Fusion Division at the CIEMAT. In a preliminary experiment, The density of sputtered chromium atoms produced in a neon glow discharge was measured. Firstly, the laser beam was characterized by calibration of its wavelength bandwidth and energy profile and Rayleigh scattering in N 2 was used for the optical system calibration. An absolute density of Cr atoms of n= 5x10''9 cm''-3 was obtained in discharges at 100 mA and pressure of 15 mTorr and a linear dependence of the LIF signal US. current was found. These values are in agreement with those expected from the tabulated sputtering yields and the thermalization and diffusion of the sputtered atoms into the Ne plasma

  13. A comparison of hydrogen vs. helium glow discharge effects on fusion device first-wall conditioning

    International Nuclear Information System (INIS)

    Dylla, H.F.

    1989-09-01

    Hydrogen- and deuterium-fueled glow discharges are used for the initial conditioning of magnetic fusion device vacuum vessels following evacuation from atmospheric pressure. Hydrogenic glow discharge conditioning (GDC) significantly reduces the near-surface concentration of simple adsorbates, such as H 2 O, CO, and CH 4 , and lowers ion-induced desorption coefficients by typically three orders of magnitude. The time evolution of the residual gas production observed during hydrogen-glow discharge conditioning of the carbon first-wall structure of the TFTR device is similar to the time evolution observed during hydrogen GDC of the initial first-wall configuration in TFTR, which was primarily stainless steel. Recently, helium GDC has been investigated for several wall-conditioning tasks on a number of tokamaks including TFTR. Helium GDC shows negligible impurity removal with stainless steel walls. For impurity conditioning with carbon walls, helium GDC shows significant desorption of H 2 O, CO, and CO 2 ; however, the total desorption yield is limited to the monolayer range. In addition, helium GDC can be used to displace hydrogen isotopes from the near-surface region of carbon first-walls in order to lower hydrogenic retention and recycling. 38 refs., 6 figs

  14. Characterization of the large area plane-symmetric low-pressure DC glow discharge

    Science.gov (United States)

    Avtaeva, S.; Gorokhovsky, V.; Myers, S.; Robertson, S.; Shunko, E.; Zembower, Z.

    2016-10-01

    Electron density and temperature as well as nitrogen dissociation degree in the low-pressure (10-50 mTorr) large area plane-symmetric DC glow discharge in Ar-N2 mixtures are studied by probes and spectral methods. Electron density measured by a hairpin probe is in good agreement with that derived from the intensity ratio of the N2 2nd positive system bands IC, 1 - 3/IC, 0 - 2 and from the intensity ratio of argon ions and atom lines IArII/IArI, while Langmuir probe data provides slightly higher values of electron density. Electron density in the low-pressure DC glow discharge varies with the discharge conditions in the limits of 108-1010 cm- 3. The concept of electron temperature can be used in low-pressure glow discharges with reservations. The intensity ratio of (0-0) vibrational bands of N2 1st negative and 2nd positive systems I391.4/I337.1 exhibits the electron temperature of 1.5-2.5 eV when argon fraction in the mixture is higher than nitrogen fraction and this ratio quickly increases with nitrogen fraction up to 10 eV in pure nitrogen. The electron temperature calculated from Langmuir probe I-V characteristics assuming a Maxwellian EEDF, gives Te 0.3-0.4 eV. In-depth analysis of the EEDF using the second derivative of Langmuir probe I-V characteristics shows that in a low-pressure glow discharge the EEDF is non-Maxwellian. The EEDF has two populations of electrons: the main background non-Maxwellian population of ;cold; electrons with the mean electron energy of 0.3-0.4 eV and the small Maxwellian population of ;hot; electrons with the mean electron energy of 1.0-2.5 eV. Estimations show that with electron temperature lower than 1 eV the rate of the direct electron impact ionization of N2 is low and the main mechanism of N2 ionization becomes most likely Penning and associative ionization. In this case, assumptions of the intensity ratio IN2+, 391/IN2, 337 method are violated. In the glow discharge, N2 dissociation degree reaches about 7% with the argon

  15. Analysis of nickel-base alloys by Grimm-type glow discharge emission and x-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Ferreira, N.P.; Strauss, J.A.; Van Maarseveen, I.; Ivanfy, A.B.

    1985-01-01

    Nickel-base alloys can be analysed as satisfactorily as steels by XRF as well as by the Grimm-type source, in spite of problems caused by element combinations, spectral line overlap and the influence of the structure and heat conduction properties on sputtering in the glow discharge source. This extended abstract briefly discusses the use of Grimm-type glow discharge emission and XRF as techniques for the analysis of nickel-base alloys

  16. Dynamic model based on voltage transfer curve for pattern formation in dielectric barrier glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ben; He, Feng; Ouyang, Jiting, E-mail: jtouyang@bit.edu.cn [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Duan, Xiaoxi [Research Center of Laser Fusion, CAEP, Mianyang 621900 (China)

    2015-12-15

    Simulation work is very important for understanding the formation of self-organized discharge patterns. Previous works have witnessed different models derived from other systems for simulation of discharge pattern, but most of these models are complicated and time-consuming. In this paper, we introduce a convenient phenomenological dynamic model based on the basic dynamic process of glow discharge and the voltage transfer curve (VTC) to study the dielectric barrier glow discharge (DBGD) pattern. VTC is an important characteristic of DBGD, which plots the change of wall voltage after a discharge as a function of the initial total gap voltage. In the modeling, the combined effect of the discharge conditions is included in VTC, and the activation-inhibition effect is expressed by a spatial interaction term. Besides, the model reduces the dimensionality of the system by just considering the integration effect of current flow. All these greatly facilitate the construction of this model. Numerical simulations turn out to be in good accordance with our previous fluid modeling and experimental result.

  17. Non-linear macro evolution of a dc driven micro atmospheric glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Xu, S. F.; Zhong, X. X., E-mail: xxzhong@sjtu.edu.cn [The State Key Laboratory on Fiber Optic Local Area, Communication Networks and Advanced Optical Communication Systems, Key Laboratory for Laser Plasmas and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2015-10-15

    We studied the macro evolution of the micro atmospheric glow discharge generated between a micro argon jet into ambient air and static water. The micro discharge behaves similarly to a complex ecosystem. Non-linear behaviors are found for the micro discharge when the water acts as a cathode, different from the discharge when water behaves as an anode. Groups of snapshots of the micro discharge formed at different discharge currents are captured by an intensified charge-coupled device with controlled exposure time, and each group consisted of 256 images taken in succession. Edge detection methods are used to identify the water surface and then the total brightness is defined by adding up the signal counts over the area of the micro discharge. Motions of the water surface at different discharge currents show that the water surface lowers increasingly rapidly when the water acts as a cathode. In contrast, the water surface lowers at a constant speed when the water behaves as an anode. The light curves are similar to logistic growth curves, suggesting that a self-inhibition process occurs in the micro discharge. Meanwhile, the total brightness increases linearly during the same time when the water acts as an anode. Discharge-water interactions cause the micro discharge to evolve. The charged particle bomb process is probably responsible for the different behaviors of the micro discharges when the water acts as cathode and anode.

  18. Study of surface atmospheric pressure glow discharge plasma based on ultrathin laminated electrodes in air

    Science.gov (United States)

    Zhao, Luxiang; Liu, Wenzheng; Li, Zhiyi; Ma, Chuanlong

    2018-05-01

    A method to generate large-area surface plasma in air by micro-discharge is proposed. Two ultrathin laminated electrode structures of non-insulating and insulating types were formed by using the nanoscale ITO conductive layer. The surface glow discharge in atmospheric air is realized in low discharge voltage by constructing the special electric field of two-dimensional unidirectional attenuation. In particular, the insulating electrode structure can avoid the loss of ITO electrodes so that the discharge stability can be increased, and the treated objects can be prevented from metal ion pollution caused by the electrode in the discharge. It has broad application prospects in the fields of aerodynamics and material surface treatment.

  19. Synthesis of Poly (Butyl Methacrylate/Butyl Acrylate) Highly Absorptive Resin Using Glow Discharge Electrolysis

    International Nuclear Information System (INIS)

    Li Yan; Yao Mengqi; Liao Ruirui; Yang Wu; Gao Jinzhang; Ren Jie

    2014-01-01

    A highly absorptive resin poly (butyl methacrylate (BMA)-co-butyl acrylate (BA)) was prepared by emulsion polymerization, which was initiated by glow discharge electrolysis plasma (GDEP). The effects of discharge voltage, discharge time, monomer ratio and the amounts of cross-linking agent were examined and discussed in detail. The chemical structure of the obtained resin was characterized by means of attenuated total reflectance Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The optimal conditions were obtained as: discharge voltage was 600 V, discharge time was 8 min, the ratios of BMA:BA being 2:1 for chloroform and 3:1 for xylene, with 2% N, N'-methylenebis. Under optimal conditions, the oil absorbency was 70 g/g for chloroform and 46 g/g for xylene. Moreover, the absorptive dynamical behavior of the resulting resin was also investigated

  20. Charged particle emission effects on the characteristics of glow discharges with oscillating electrons

    CERN Document Server

    Nikulin, S P

    2001-01-01

    One discusses the effect of selection of charged particles on conditions to maintain and the characteristics of a glow discharge with oscillating electrons. It is shown that there is a pressure dependent optimal level of ion selection when the energy efficiency of ion source reaches its maximum value. It is determined that departure of fast ionizing electrons affects negatively the discharge maintenance wile emission of slow plasma electrons may promote maintenance of a discharge high current shape. It is shown that high efficient electron emission without violation of a discharge stability may take place in a magnetic field due to different nature of spatial distributions of fast and slow particles in discharges with electron oscillation

  1. Electron energy distribution function in a cathode fall region of DC-glow discharge

    International Nuclear Information System (INIS)

    Elakshar, F.F.; Garamoon, A.A.; Hassouba, M.A.

    1997-01-01

    Recently a substantial effort has been devoted towards the development of a quantitative microscopic measurements in the cathode fall region of the DC-glow discharge magnetron sputtering unit. The electron energy distribution function (EEDF) has been measured using a single Langmuir probe at the edge of the cathode fall. Two groups of electrons are observed in helium and argon gas discharges. The two groups have no chance to be thermalized since they leave the cathode fall region fast. The electron temperature measurements have been compared with spectroscopic determination. Plasma density has been computed and compared with probe measurements. Sources of the two groups of electrons are also discussed. (author)

  2. Stabilization of a cold cathode electron beam glow discharge for surface treatment

    International Nuclear Information System (INIS)

    Mingolo, N.; Gonzalez, C.R.; Martinez, O.E.; Rocca, J.J.

    1997-01-01

    We have demonstrated that the reproducibility of electron beam pulses generated by a high power, cold cathode glow discharge is greatly improved by adding a small continuous keep-alive discharge current. A current of the order of 200 μA was found to limit the shot to shot current variation to within 1.5%. This stabilization in turn reduces by an order of magnitude the fluctuations of the energy density deposited on the target, demonstrating a reliable energy source for surface treatment. copyright 1997 American Institute of Physics

  3. Stabilization of a cold cathode electron beam glow discharge for surface treatment

    Energy Technology Data Exchange (ETDEWEB)

    Mingolo, N.; Gonzalez, C.R. [Lab. de Haces Dirigidos, Depto. de Fisica, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina); Martinez, O.E. [Lab. de Electronica Cuantica, Depto. de Fisica, Universidad de Buenos Aires, Pabellon 1, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Rocca, J.J. [Department of Electrical Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States)

    1997-10-01

    We have demonstrated that the reproducibility of electron beam pulses generated by a high power, cold cathode glow discharge is greatly improved by adding a small continuous keep-alive discharge current. A current of the order of 200 {mu}A was found to limit the shot to shot current variation to within 1.5{percent}. This stabilization in turn reduces by an order of magnitude the fluctuations of the energy density deposited on the target, demonstrating a reliable energy source for surface treatment. {copyright} {ital 1997 American Institute of Physics.}

  4. Plasma actuators for active flow control based on a glow discharge

    International Nuclear Information System (INIS)

    Kühn, M.; Kühn-Kauffeldt, M.; Schein, J.; Belinger, A.

    2017-01-01

    In this work a glow discharge based active flow control for high flow velocities and low Reynolds numbers is presented. Unlike common plasma actuators such as dielectric barrier discharge (DBD) or spark jets, this actuator uses small impulse bits at frequencies. The actuator is optimized for frequencies up to 40 kHz to counter Tollmien Schlichting wave effects and so reduce overall air foil drag. Several measurements to prove the non-eroding effect of the actuator and the electrical properties were performed. It was found that the actuator is capable of operating at high frequencies without measurable erosion. (paper)

  5. Comparison of macroscopic properties of electrons in plasmas of beam-plasma and glow discharges

    International Nuclear Information System (INIS)

    Winkler, R.; Wilhelm, J.; Starykh, V.V.

    1979-01-01

    The theoretical basis of the comparison are adequate Boltzmann equations for the electron component of the beam discharge plasma and the glow discharge plasma. We included the turbulent field or the direct electric field in the mentioned plasma types and all important binary collision processes as well as the Coulomb interaction between the charged particles. The comparison was performed in hydrogen under the condition of equal power input per volumen unit of both plasmas in dependence of the turbulence energy per one electron U, for the ionization degree (nsub(e)/N)sub(g) = 10 -6 and the pressure p 0 sup(g) = 1 Torr of the glow discharge plasma and for the ionization degrees (nsub(e)/N)sub(b) = 10 -3 , 10 -2 , 10 -1 and the pressure p 0 sup(b) = 10 -2 Torr of the beam discharge plasma which are typical for the existence of both plasma types. Based upon the numerical solutions of the Boltzmann equations under the mentioned additional conditions we compared the energy distribution functions of the electrons, the mean energy and the power losses of the electrons due to the different collision processes with the molecules and the ions. Especially a law for similarity of the electron kinetics of the two collision dominated plasma types was found and the main channels for the transfer of the field energy in both plasmas were determined. The results obtained were applied for assesing the perspectives of the beam discharged plasma as a plasmachemical reactor. (author)

  6. Transitions between corona, glow, and spark regimes of nanosecond repetitively pulsed discharges in air at atmospheric pressure

    Science.gov (United States)

    Pai, David Z.; Lacoste, Deanna A.; Laux, Christophe O.

    2010-05-01

    In atmospheric pressure air preheated from 300 to 1000 K, the nanosecond repetitively pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and interelectrode gap distance) of each discharge regime. In particular, the experimental conditions necessary for the glow regime of NRP discharges have been determined, with the notable result that there exists a minimum and maximum gap distance for its existence at a given ambient gas temperature. The minimum gap distance increases with decreasing gas temperature, whereas the maximum does not vary appreciably. To explain the experimental results, an analytical model is developed to explain the corona-to-glow (C-G) and glow-to-spark (G-S) transitions. The C-G transition is analyzed in terms of the avalanche-to-streamer transition and the breakdown field during the conduction phase following the establishment of a conducting channel across the discharge gap. The G-S transition is determined by the thermal ionization instability, and we show analytically that this transition occurs at a certain reduced electric field for the NRP discharges studied here. This model shows that the electrode geometry plays an important role in the existence of the NRP glow regime at a given gas temperature. We derive a criterion for the existence of the NRP glow regime as a function of the ambient gas temperature, pulse repetition frequency, electrode radius of curvature, and interelectrode gap distance.

  7. On the physical processes ruling an atmospheric pressure air glow discharge operating in an intermediate current regime

    International Nuclear Information System (INIS)

    Prevosto, L.; Mancinelli, B.; Chamorro, J. C.; Cejas, E.; Kelly, H.

    2015-01-01

    Low-frequency (100 Hz), intermediate-current (50 to 200 mA) glow discharges were experimentally investigated in atmospheric pressure air between blunt copper electrodes. Voltage–current characteristics and images of the discharge for different inter-electrode distances are reported. A cathode-fall voltage close to 360 V and a current density at the cathode surface of about 11 A/cm 2 , both independent of the discharge current, were found. The visible emissive structure of the discharge resembles to that of a typical low-pressure glow, thus suggesting a glow-like electric field distribution in the discharge. A kinetic model for the discharge ionization processes is also presented with the aim of identifying the main physical processes ruling the discharge behavior. The numerical results indicate the presence of a non-equilibrium plasma with rather high gas temperature (above 4000 K) leading to the production of components such as NO, O, and N which are usually absent in low-current glows. Hence, the ionization by electron-impact is replaced by associative ionization, which is independent of the reduced electric field. This leads to a negative current-voltage characteristic curve, in spite of the glow-like features of the discharge. On the other hand, several estimations show that the discharge seems to be stabilized by heat conduction; being thermally stable due to its reduced size. All the quoted results indicate that although this discharge regime might be considered to be close to an arc, it is still a glow discharge as demonstrated by its overall properties, supported also by the presence of thermal non-equilibrium

  8. Radio frequency glow discharge source with integrated voltage and current probes used for evaluation of discharge parameters

    International Nuclear Information System (INIS)

    Wilken, L.; Hoffmann, V.; Wetzig, K.

    2006-01-01

    A radio frequency (rf) Grimm-type glow discharge source for the chemical analysis of solid samples, with integrated voltage and current probes, was developed. All elements of a plasma equivalent circuit are determined from the measured current-voltage characteristics. The procedure is based on the independent evaluation of the ion current and electron current region. The physical meaning of the parameters is investigated by comparisons with measurements from dc glow discharges. We found that the reduced rf current of the powered electrode is comparable to the reduced current in dc discharges. A formula is developed that corrects the reduced current due to gas heating. The sheath thickness at the powered rf electrode is evaluated and is between 75 and 1100 μm. The voltage of the bulk plasma is in the range 2-15 V, and the resistance is between 30 and 400 Ω. The bulk plasma consumes about 3% of the total power, and the reduced voltage is comparable to the reduced electrical field in the positive column of direct current discharges. The sheath voltage at the grounded electrode is in the range 25-100 V, the capacities are between 10 and 400 pF, and the resistances are in the range 100 Ω-5000 Ω. We also found invariants for the evaluated sheath parameters

  9. Protein destruction by a helium atmospheric pressure glow discharge: Capability and mechanisms

    International Nuclear Information System (INIS)

    Deng, X. T.; Shi, J. J.; Kong, M. G.

    2007-01-01

    Biological sterilization represents one of the most exciting applications of atmospheric pressure glow discharges (APGD). Despite the fact that surgical instruments are contaminated by both microorganisms and proteinaceous matters, sterilization effects of APGD have so far been studied almost exclusively for microbial inactivation. This work presents the results of a detailed investigation of the capability of a helium-oxygen APGD to inactivate proteins deposited on stainless-steel surfaces. Using a laser-induced fluorescence technique for surface protein measurement, a maximum protein reduction of 4.5 logs is achieved by varying the amount of the oxygen admixture into the background helium gas. This corresponds to a minimum surface protein of 0.36 femtomole/mm 2 . It is found that plasma reduction of surface-borne protein is through protein destruction and degradation, and that its typically biphasic reduction kinetics is influenced largely by the thickness profile of the surface protein. Also presented is a complementary study of possible APGD protein inactivation mechanisms. By interplaying the protein inactivation kinetics with optical emission spectroscopy, it is shown that the main protein-destructing agents are excited atomic oxygen (via the 777 and 844 nm emission channels) and excited nitride oxide (via the 226, 236, and 246 nm emission channels). It is also demonstrated that the most effective protein reduction is achieved possibly through a synergistic effect between atomic oxygen and nitride oxide. This study is a useful step toward a full confirmation of the efficacy of APGD as a sterilization technology for surgical instruments contaminated by prion proteins

  10. Study of glow discharge positive column with cloud of disperse particles

    International Nuclear Information System (INIS)

    Polyakov, D.N.; Shumova, V.V.; Vasilyak, L.M.; Fortov, V.E.

    2011-01-01

    The study aims to describe plasma parameters changes induced by clouds of disperse micron size particles. Dust clouds were formed in the positive column of glow discharge in air at pressure 0.1-0.6 torr and current 0.1-3 mA. The simultaneous registration of discharge voltage and dust cloud parameters was carried out. Experimental results were simulated using diffusion model. The dust cloud is shown to smooth the radial electron concentration profile, increase electric field strength and electron temperature and stabilize the discharge. The cloud is demonstrated to be a trap for positive ions without increase of discharge current. -- Highlights: → 25% increase of longitudinal electric field strength in discharge with dust cloud. → The smoothing effect of dust cloud on radial electron and ion concentration profiles. → Dust cloud as a trap for positive ions without increase of discharge current. → Increase of electron temperature in discharge with dust cloud. → Increase of discharge stability in presence of dust cloud.

  11. Boltzmann statistical consideration on the excitation mechanism of iron atomic lines emitted from glow discharge plasmas

    International Nuclear Information System (INIS)

    Zhang Lei; Kashiwakura, Shunsuke; Wagatsuma, Kazuaki

    2011-01-01

    A Boltzmann plot for many iron atomic lines having excitation energies of 3.3–6.9 eV was investigated in glow discharge plasmas when argon or neon was employed as the plasma gas. The plot did not show a linear relationship over a wide range of the excitation energy, but showed that the emission lines having higher excitation energies largely deviated from a normal Boltzmann distribution whereas those having low excitation energies (3.3–4.3 eV) well followed it. This result would be derived from an overpopulation among the corresponding energy levels. A probable reason for this is that excitations for the high-lying excited levels would be caused predominantly through a Penning-type collision with the metastable atom of argon or neon, followed by recombination with an electron and then stepwise de-excitations which can populate the excited energy levels just below the ionization limit of iron atom. The non-thermal excitation occurred more actively in the argon plasma rather than the neon plasma, because of a difference in the number density between the argon and the neon metastables. The Boltzmann plots yields important information on the reason why lots of Fe I lines assigned to high-lying excited levels can be emitted from glow discharge plasmas. - Highlights: ► This paper shows the excitation mechanism of Fe I lines from a glow discharge plasma. ► A Boltzmann distribution is studied among iron lines of various excitation levels. ► We find an overpopulation of the high-lying energy levels from the normal distribution. ► It is caused through Penning-type collision of iron atom with argon metastable atom.

  12. Boltzmann statistical consideration on the excitation mechanism of iron atomic lines emitted from glow discharge plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lei; Kashiwakura, Shunsuke; Wagatsuma, Kazuaki, E-mail: wagatuma@imr.tohoku.ac.jp

    2011-11-15

    A Boltzmann plot for many iron atomic lines having excitation energies of 3.3-6.9 eV was investigated in glow discharge plasmas when argon or neon was employed as the plasma gas. The plot did not show a linear relationship over a wide range of the excitation energy, but showed that the emission lines having higher excitation energies largely deviated from a normal Boltzmann distribution whereas those having low excitation energies (3.3-4.3 eV) well followed it. This result would be derived from an overpopulation among the corresponding energy levels. A probable reason for this is that excitations for the high-lying excited levels would be caused predominantly through a Penning-type collision with the metastable atom of argon or neon, followed by recombination with an electron and then stepwise de-excitations which can populate the excited energy levels just below the ionization limit of iron atom. The non-thermal excitation occurred more actively in the argon plasma rather than the neon plasma, because of a difference in the number density between the argon and the neon metastables. The Boltzmann plots yields important information on the reason why lots of Fe I lines assigned to high-lying excited levels can be emitted from glow discharge plasmas. - Highlights: Black-Right-Pointing-Pointer This paper shows the excitation mechanism of Fe I lines from a glow discharge plasma. Black-Right-Pointing-Pointer A Boltzmann distribution is studied among iron lines of various excitation levels. Black-Right-Pointing-Pointer We find an overpopulation of the high-lying energy levels from the normal distribution. Black-Right-Pointing-Pointer It is caused through Penning-type collision of iron atom with argon metastable atom.

  13. Application of Radio-Frequency Plasma Glow Discharge to Removal of Uranium Dioxide from Metal Surfaces

    International Nuclear Information System (INIS)

    El-Genk, Mohamed S.; Saber, Hamed H.

    2000-01-01

    Recent experiments have shown that radio-frequency (rf) plasma glow discharge using NF 3 gas is an effective technique for the removal of uranium oxide from metal surfaces. The results of these experiments are analyzed to explain the measured dependence of the UO 2 removal or etch rate on the NF 3 gas pressure and the absorbed power in the plasma. The NF 3 gas pressure in the experiments was varied from 10.8 to 40 Pa, and the deposited power in the plasma was varied from 25 to 210 W. The UO 2 etch rate was strongly dependent on the absorbed power and, to a lesser extent, on the NF 3 pressure and decreased exponentially with immersion time. At 210 W and 17 Pa, all detectable UO 2 in the samples (∼10.6 mg each) was removed at the endpoint, whereas the initial etch rate was ∼3.11 μm/min. When the absorbed power was ≤50 W, however, the etch rate was initially ∼0.5 μg/min and almost zero at the endpoint, with UO 2 only partially etched. This self-limiting etching of UO 2 at low power is attributed to the formation of nonvolatile intermediates UF 2 , UF 3 , UF 4 , UF 5 , UO 2 F, and UO 2 F 2 on the surface. Analysis indicated that the accumulation of UF 6 and, to a lesser extent, O 2 near the surface partially contributed to the exponential decrease in the UO 2 etch rate with immersion time. Unlike fluorination with F 2 gas, etching of UO 2 using rf glow discharge is possible below 663 K. The average etch rates of the amorphous UO 2 in the NF 3 experiments are comparable to the peak values reported in other studies for crystalline UO 2 using CF 4 /O 2 glow discharge performed at ∼150 to 250 K higher sample temperatures

  14. Child-Langmuir law for cathode sheath of glow discharge in CO2

    International Nuclear Information System (INIS)

    Lisovskiy, V.A.; Krol, H.H.; Osmayev, R.O.; Yegorenkov, V.D.

    2016-01-01

    This work is devoted to the determination of the law that may be applicable to the description of the cathode sheath in CO 2 . To this end three versions of the Child-Langmuir law have been considered - a collision free one (for the ions moving through a cathode sheath without collisions with gas molecules) as well as two collision- related versions - one for a constant mean free path of positive ions and one for a constant mobility of positive ions. The current-voltage characteristics and the cathode sheath thickness of the glow discharge in CO 2 have been simultaneously measured in the pressure range from 0.05 to 1 Torr and with the discharge current values up to 80 mA. In the whole range of the discharge conditions we have studied the cathode sheath characteristics are found to obey correctly only to the Child-Langmuir law version with a constant ion mobility.

  15. Electronic perturbation investigations into excitation and ionization in the millisecond pulsed glow discharge plasma

    International Nuclear Information System (INIS)

    Li Lei; Robertson-Honecker, Jennifer; Vaghela, Vishal; King, Fred L.

    2006-01-01

    This study employed a power perturbation method to examine the energy transfer processes at different locations within the afterpeak regime of a millisecond pulsed glow discharge plasma. Brief power perturbation pulses were applied during the afterpeak regime altering the environment of the collapsing plasma. Responses of several transitions to the power perturbations were measured via atomic emission and absorption spectroscopic methods at various distances from the surface of the cathode. The experimental data provide further insight into the energy transfer processes that occur at different spatial locations and in different temporal regimes of these pulsed glow discharge plasmas. Although the enhancement of the large population of metastable argon atoms is again confirmed, the mechanism responsible for this enhancement remains unclear. The most likely possibility involves some form of ion-electron recombination followed by radiative relaxation of the resulting species. The metastable argon atoms subsequently Penning ionize sputtered copper atoms which then appear to undergo a similar ion-electron recombination process yielding variable degrees of observable afterpeak emission for copper atom transitions. The kinetic information of these processes was approximated from the corresponding relaxation time. The electron thermalization time allowing for recombination with ions was found to be ∼25 μs after the discharge power termination

  16. Cleaning and conditioning of the walls of plasma devices by glow discharges in hydrogen

    International Nuclear Information System (INIS)

    Waelbroeck, F.; Winter, J.; Ali-Khan, I.; Wienhold, P.; Dietz, K.J.

    1980-12-01

    The influence of a number of parameters on the cleaning and preconditioning efficiency of a combined rf and glow (RG) discharge is studied experimentally. The emphasis is laid on problems of oxygen removal from the surface. The important parameters are the wall temperature Tsub(W), the pump speed SP, the current Isub(G)D of the glow discharge and the hydrogen pressure P 2 . In a device with a ratio SP/S = 0,1 ms -1 (S: inner area), a rapid deoxidation is achieved when T-W >= 200 0 C. At room temperature, the oxide layer is reduced from a (carbon-free) surface when 1 to 2% of methane is added to the hydrogen: carbon monoxide is formed and evacuated. Admixture of other gases such as He, Ne do not increase the cleaning efficiency. An equation derived from a simplified model describes semi-quantitatively the observed parametric dependances. The tendency for arc spots to occur during the initial phases of the discharge depends on the preconditioning of the wall: a prolonged bake-out at 200 0 C leads to the non-appearance of arcs in all cases examined. Problems arise when a quadrupole residual gas analyser is used to measure the partial pressure of water in hydrogen. These are analysed and a conditioning technique is described which has proven to be appropriate in our measurements. (orig.)

  17. Two-dimensional electrodynamic structure of the normal glow discharge in an axial magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Surzhikov, S. T., E-mail: surg@ipmnet.ru [Russian Academy of Sciences, Institute for Problems in Mechanics (Russian Federation)

    2017-03-15

    Results are presented from numerical simulations of an axisymmetric normal glow discharge in molecular hydrogen and molecular nitrogen in an axial magnetic field. The charged particle densities and averaged azimuthal rotation velocities of electrons and ions are studied as functions of the gas pressure in the range of 1–5 Torr, electric field strength in the range of 100–600 V/cm, and magnetic field in the range of 0.01–0.3 T. It is found that the axial magnetic field does not disturb the normal current density law.

  18. Pulsed glow discharge mass spectrometry for molecular depth profiling of polymers

    International Nuclear Information System (INIS)

    Lobo, L.; Pereiro, R.; Sanz-Medel, A.; Bordel, N.; Pisonero, J.; Licciardello, A.; Tuccitto, N.; Tempez, A.; Chapon, P.

    2009-01-01

    Full text: Nowadays thin films of polymeric materials involve a wide range of industrial applications, so techniques capable of providing in-depth profile information are required. Most of the techniques available for this purpose are based on the use of energetic particle beams which interact with polymers producing undesirable physicochemical modifications. Radiofrequency pulsed glow discharge (rf-pulsed-GD) coupled to time-of-flight mass spectrometry (TOFMS) could afford the possibility of acquiring both elemental and molecular information creating minimal damage to surfaces and thereby obtaining depth profiles. This work will evaluate rf-GDs coupled to an orthogonal TOFMS for direct analysis of polymers. (author)

  19. Nitridation Of The A A 2024 T3 Aluminium By The Glow Discharge Plasma Technique

    International Nuclear Information System (INIS)

    Mudjiman, Supardjono; Sujitno, Tjipto; Sudjatmoko

    1996-01-01

    Nitridation of A A 2024 T3 aluminium by means of plasma glow discharge technique has been carried out. For this purpose, the experiments were carried out at the temperature 30 o C, 60 o C, 100 o C, 150 o C, 200 o C, and 250 o C whereas the nitridation time were varied at 5 minutes, 15 minutes, 40 minutes, 90 minutes and 180 minutes. The results showed that the optimum temperature and time of nitridation were 60 o C and 90 minutes respectively and the hardness increased from 115 to 166 KHN

  20. Surface modification of austenitic steel by various glow-discharge nitriding methods

    Directory of Open Access Journals (Sweden)

    Tomasz Borowski

    2015-09-01

    Full Text Available Recent years have seen intensive research on modifying glow-discharge nitriding processes. One of the most commonly used glow-discharge methods includes cathodic potential nitriding (conventional method, and active screen plasma nitriding. Each of these methods has a number of advantages. One very important, common feature of these techniques is full control of the microstructure, chemical and phase composition, thickness and the surface topography of the layers formed. Another advantage includes the possibility of nitriding such materials as: austenitic steels or nickel alloys, i.e. metallic materials which do not diffuse nitrogen as effectively as ferritic or martensitic steels. However, these methods have some disadvantages as well. In the case of conventional plasma nitriding, engineers have to deal with the edge effect, which makes it difficult to use this method for complexly shaped components. In turn, in the case of active screen plasma nitriding, the problem disappears. A uniform, smooth layer forms, but is thinner, softer and is not as resistant to friction compared to layers formed using the conventional method. Research is also underway to combine these methods, i.e. use an active screen in conventional plasma nitriding at cathodic potential. However, there is a lack of comprehensive data presenting a comparison between these three nitriding processes and the impact of pulsating current on the formation of the microstructure and functional properties of austenitic steel surfaces. The article presents a characterisation of nitrided layers produced on austenitic X2CrNiMo17-12-2 (AISI 316L stainless steel in the course of glow-discharge nitriding at cathodic potential, at plasma potential and at cathodic potential incorporating an active screen. All processes were carried out at 440 °C under DC glow-discharge conditions and in 100 kHz frequency pulsating current. The layers were examined in terms of their microstructure, phase and

  1. Analysis of iron-base alloys by low-wattage glow discharge emission spectrometry

    International Nuclear Information System (INIS)

    Wagatsuma, K.; Hirokawa, K.

    1984-01-01

    Several iron-base alloys were investigated by low-wattage glow discharge emission spectrometry. The emission intensity principally depended on the sputtering parameters of constituent elements in the alloy. However, in the case of chromium, stable and firm oxides formed on the surface influencing the yield of ejected atoms. This paper discusses the relation between the sputtering parameters in Fe-Ni, Fe-Cr, and Fe-Co alloys and their relative emission intensities. Additionally, quantitative analysis was performed for some ternary iron-base alloys and commercial stainless steels with the calibration factors of binary alloy systems

  2. Variation of the Plasma Density in a Glow Discharge Upon the Application of A High Voltage

    International Nuclear Information System (INIS)

    Akman, S.

    2004-01-01

    It is emphasized and demonstrated that, during the formation of an ion-matrix sheath in a glow discharge upon the application of a high voltage pulse, the existing neutral plasma density should change as well. An explicit and practical expression for the neutral plasma density in terms of the gas pressure, secondary electron emission coefficient and the applied voltage is derived, so that the consequent sheath behavior can be formulated correctly. The theoretical result is compared with the data of an experiment, particularly designed and performed to test its validity, and found to be in good agreement with the latter

  3. A simple theoretical approach to determine relative ion yield (RIY) in glow discharge mass spectrometry (GDMS)

    Energy Technology Data Exchange (ETDEWEB)

    Born, Sabine [Degussa AG, Hanau (Germany); Matsunami, Noriaki [Nagoya Univ. (Japan). Faculty of Engineering; Tawara, Hiroyuki [National Inst. for Fusion Science, Toki, Gifu (Japan)

    2000-01-01

    Direct current glow discharge mass spectrometry (dc-GDMS) has been applied to detect impurities in metals. The aim of this study is to understand quantitatively the processes taking place in GDMS and establish a model to calculate the relative ion yield (RIY), which is inversely proportional to the relative sensitivity factor (RSF), in order to achieve better agreement between the calculated and the experimental RIYs. A comparison is made between the calculated RIY of the present model and the experimental RIY, and also with other models. (author)

  4. Child–Langmuir law applicability for a cathode sheath description of glow discharge in hydrogen

    International Nuclear Information System (INIS)

    Lisovskiy, V A; Artushenko, K P; Yegorenkov, V D

    2016-01-01

    The present paper reveals that the Child-Langmuir law version with the constant ion mobility has to be applied for the cathode sheath description of the glow discharge in hydrogen. Using the analytical model we demonstrate that even in a high electric field the constant mobility law version rather than that for the constant ion mean free path has to hold in the case of impeded charge exchange and the dominant effect of polarization forces on the ion motion through the cathode sheath. (paper)

  5. Study of stability of dc glow discharges with the use of Comsol Multiphysics software

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, P G C; Benilov, M S; Faria, M J [Departamento de Fisica, Universidade da Madeira, Largo do Municipio, 9000 Funchal (Portugal)

    2011-10-19

    Stability of different axially symmetric modes of current transfer in dc glow discharges is investigated in the framework of the linear stability theory with the use of Comsol Multiphysics software. Conditions of current-controlled microdischarges in xenon are treated as an example. Both real and complex eigenvalues have been detected, meaning that perturbations can vary with time both monotonically and with oscillations. In general, results given by the linear stability theory confirm intuitive concepts developed in the literature and conform to the experiment. On the other hand, suggestions are provided for further experimental and theoretical work.

  6. Dynamics of excited nitrogen molecular states in glow- and afterglow phases of discharge: experiment and modeling

    International Nuclear Information System (INIS)

    Napartovich, A.P.; Akishev, Yu.S.; Dyatko, N.A.; Grushin, M.E.; Filippov, A.V.; Trushkin, N.I.

    2001-01-01

    Population dynamics for a number of levels from N2 ( A 3 Σ + u ), N 2 (B 3 Π g ) and N 2 (C 3 Π u ) manifolds was studied spectroscopically in a long pulse glow discharge in pure nitrogen and in afterglow at pressure 50 Torr. Overshot in time behaviour of N 2 (A 3Σ + u ), N 2 (B 3 Π g ) and N 2 (C 3 Π u ) levels populations was revealed. A rather complete kinetic model is developed for conditions of the experiments. Results of comparison are analyzed

  7. Sputtering in a glow discharge ion source - pressure dependence: theory and experiment

    International Nuclear Information System (INIS)

    Mason, R.S.; Pichilingi, Melanie

    1994-01-01

    A simplified theoretical expression has been developed for a glow discharge to show how the average cathode erosion rate (expressed as the number of atoms per ion of the total bombarding flux) varies with primary sputter yield, pressure, 'diffusion length' and sputtered atom 'stopping' cross section. An inverse pressure dependence is predicted which correlates well with experiment in the 2 and He, tend to converge. It is suggested that this could be due to a change in the mechanism to self-sputtering. Under constant conditions, the erosion rates of different cathode materials still correlate quite well with the differences in their primary sputter yields. (author)

  8. Glow discharge, its sensitivity to infra-red radiation. Observations made during the testing of multiwire proportional chambers

    International Nuclear Information System (INIS)

    Marsh, J.B.; Souten, K.H.; O'Hagan, B.

    1979-05-01

    It has been shown that under glow discharge conditions, multiwire proportional chambers are sensitive to infra-red radiation. Discharge current measurements and light change measurements have been made and the effect of the input window on the output signal and the importance of the finish of the anode and HT wires have been investigated. From these observations it would appear that a glow discharge in the form detailed in this report is sensitive to infra-red radiation though work is still required to optimise the parameters of such a device for IR detection or solar cell technology. (UK)

  9. Auxiliary glow discharge in the trigger unit of a hollow-cathode thyratron

    Energy Technology Data Exchange (ETDEWEB)

    Korolev, Yu. D.; Landl, N. V., E-mail: landl@lnp.hcei.tsc.ru; Geyman, V. G.; Frants, O. B.; Shemyakin, I. A.; Nekhoroshev, V. O. [Russian Academy of Sciences, Institute of High-Current Electronics, Siberian Branch (Russian Federation)

    2016-08-15

    Results from studies of a low-current glow discharge with a hollow cathode are presented. A specific feature of the discharge conditions was that a highly emissive tablet containing cesium carbonate was placed in the cathode cavity. In the absence of a tablet, the discharge ignition voltage was typically ≥3.5 kV, while the burning voltage was in the range of 500–600 V. The use of the tablet made it possible to decrease the ignition voltage to 280 V and maintain the discharge burning voltage at a level of about 130 V. A model of the current sustainment in a hollow-cathode discharge is proposed. Instead of the conventional secondary emission yield, the model uses a generalized emission yield that takes into account not only ion bombardment of the cathode, but also the emission current from an external source. The model is used to interpret the observed current−voltage characteristics. The results of calculations agree well with the experimental data. It is shown that, in some discharge modes, the external emission current from the cathode can reach 25% of the total discharge current.

  10. Anode spot patterns and fluctuations in an atmospheric-pressure glow discharge in helium

    International Nuclear Information System (INIS)

    Arkhipenko, V I; Safronau, Y A; Simonchik, L V; Tsuprik, I M; Callegari, Th

    2013-01-01

    Oscillations of the main parameters (voltage on electrodes, potential, light intensity and discharge current) in a dc atmospheric-pressure glow discharge in helium are investigated in a range of currents from milliamperes to several amperes. It is established that these oscillations are connected with the existence of anode spots. In the case of a single spot, fluctuations of discharge light intensity are observed when the supply voltage exceeds the breakdown voltage for the interelectrode gap. At the same time, voltage fluctuations have the form of relaxation oscillations with a frequency that depends on the electrical parameters of the external circuit. With an increase in discharge gap and current, the number of spots increases. They form a stable structure, and the fluctuations of current and voltage stay harmonic. The brightness of the spots seems to be determined by the frequency of their blinking. The amplitude of current fluctuation increases with the increase in discharge current and can be up to 15% of its average value. The frequency of current oscillations, which is about 0.75 MHz at a current of 0.5 A, depends weakly on the discharge gap (it varies within ±10% for the gap interval from 1 to 10 mm). The oscillation frequency is maximal (about 0.85 MHz) at a current of about 0.4 A. At higher currents (2–4 A, depending on the discharge gap), the fluctuations disappear when a contraction of the anode region into one anode spot occurs. (paper)

  11. Transmission characteristics of microwave in a glow-discharge dusty plasma

    Science.gov (United States)

    Jia, Jieshu; Yuan, Chengxun; Gao, Ruilin; Liu, Sha; Yue, Feng; Wang, Ying; Zhou, Zhong-Xiang; Wu, Jian; Li, Hui

    2016-07-01

    In this study, the propagation characteristics of electromagnetic wave in a glow discharge plasma with dust particles are experimentally investigated. A helium alternating current glow discharge plasmas have been successfully generated. Measurements of the plasma parameters using Langmuir probes, in the absence of dust particles, provide plasma densities (ne) of 1017 m-3 and electron temperatures (Te) ranging from 2 to 4 eV. Dusty plasmas are made by adding 30 nm radius aluminum oxide (Al2O3) particles into the helium plasma. The density of the dust particle (nd) in the device is about 1011-1012 m-3. The propagation characteristics of electromagnetic waves are determined by a vector network analyzer with 4-6 GHz antennas. An apparent attenuation by the dust is observed, and the measured attenuation data are approximately in accordance with the theoretical calculations. The effects of gas pressure and input power on the propagation are also investigated. Results show that the transmission attenuation increases with the gas pressure and input power, the charged dust particles play a significant role in the microwave attenuation.

  12. Determination of trace amounts of impurities in molybdenum by spark source and glow discharge mass spectrometry

    International Nuclear Information System (INIS)

    Saito, Morimasa

    1994-01-01

    For the determination of trace and ultra-trace amounts of impurities in high-purity molybdenum, spark source mass spectrometry and glow discharge mass spectrometry were studied. In spark source mass spectrometry using the metal probe method, the liquid-helium cryogenic pump was used in order to protect the surface of the samples from oxidation. The theoretical relative sensitivity factors (Mo=1) calculated from physical properties were used. The analytical results obtained for molybdenum tablet and high-purity molybdenum were in good agreement with those obtained by other methods (atomic absorption spectrometry and others). In glow discharge mass spectrometry, the relative sensitivity factors were calculated by using the results obtained by spark source mass spectrometry and atomic absorption spectrometry, and this method was applied to the determination of ultra-trace amounts of impurities in ultra high-purity molybdenum and gave the satisfactory results. The detection limits (2σ, n=10) in the integration time of 600 s for U and Th were 0.6 ppb and 0.3 ppb, and the values for Al, Si, Cr, Mn and Cu were in the range of 10 ppb to 0.5 ppb. (author)

  13. PRODUCTION OF HIGHER STRENGTH THIN WALLED GLOW DISCHARGE POLYMER SHELLS FOR CRYOGENIC EXPERIMENTS AT OMEGA

    International Nuclear Information System (INIS)

    NIKROO, A; CZECHOWICZ, DG; CASTILLO, ER; PONTELANDOLFO, JM

    2002-01-01

    OAK A271 PRODUCTION OF HIGHER STRENGTH THIN WALLED GLOW DISCHARGE POLYMER SHELLS FOR CRYOGENIC EXPERIMENTS AT OMEGA. Thin walled polymer shells are needed for OMEGA cryogenic laser experiments. These capsules need to be about 900 (micro)m in diameter and as thin as possible (approx 1-2 (micro)m), while having enough strength to be filled with DT as fast as possible to about 1000 atm. The authors have found that by optimizing the coating parameters in the glow discharge polymer (GDP) deposition system, traditionally used for making ICF targets, they can routinely make robust, ∼ 1.5 (micro)m thick, 900 (micro)m diameter GDP shells with buckle strengths of over 0.3 atm. This is twice the strength of shells made prior to the optimization and is comparable to values quoted for polyimide shells. In addition, these shells were found to be approximately three times more permeable and over 20% denser than previously made GDP shells. The combination of higher strength and permeability is ideal for direct drive cryogenic targets at OMEGA. Shells as thin as 0.5 (micro)m have been made. In this paper, the authors discuss the shell fabrication process, effects of modifying various GDP deposition parameters on shell properties and chemical composition

  14. Borax as flux on sintering of iron Ancor Steel 1000® under glow discharge

    Science.gov (United States)

    Ariza Suarez, H. G.; Sarmiento Santos, A.; Ortiz Otálora, C. A.

    2016-02-01

    This work studies the flux effect of borax (di sodium tetraborate decahydrate) on sintering of iron Ancor Steel 1000® in abnormal glow discharge. The incidence of the percentage by weight of borax and the sintering temperature in the process were observed. Samples of powder metallurgical iron were prepared with proportions of 0.50%, 2.0%, 4.0% and 6.0% by weight of borax using the procedures of powder metallurgy. The samples were sintered at 800 and 1100°C for 30min, by glow discharge at low pressure in a reducing atmosphere composed of 20% H2+80% Ar. The samples in compact green-state were analyzed by TGA-DSC to determine the fusion process and mass loss during sintering. The analysis of microhardness and density, shows that at a sintering temperature of 800°C the sample density decreases and the sample microhardness increases with respect to sintered samples without borax. Sintered samples were analysed by DRX showing the absence of precipitates.

  15. Decomposition of toluene in a steady-state atmospheric-pressure glow discharge

    International Nuclear Information System (INIS)

    Trushkin, A. N.; Grushin, M. E.; Kochetov, I. V.; Trushkin, N. I.; Akishev, Yu. S.

    2013-01-01

    Results are presented from experimental studies of decomposition of toluene (C 6 H 5 CH 3 ) in a polluted air flow by means of a steady-state atmospheric pressure glow discharge at different water vapor contents in the working gas. The experimental results on the degree of C 6 H 5 CH 3 removal are compared with the results of computer simulations conducted in the framework of the developed kinetic model of plasma chemical decomposition of toluene in the N 2 : O 2 : H 2 O gas mixture. A substantial influence of the gas flow humidity on toluene decomposition in the atmospheric pressure glow discharge is demonstrated. The main mechanisms of the influence of humidity on C 6 H 5 CH 3 decomposition are determined. The existence of two stages in the process of toluene removal, which differ in their duration and the intensity of plasma chemical decomposition of C 6 H 5 CH 3 is established. Based on the results of computer simulations, the composition of the products of plasma chemical reactions at the output of the reactor is analyzed as a function of the specific energy deposition and gas flow humidity. The existence of a catalytic cycle in which hydroxyl radical OH acts a catalyst and which substantially accelerates the recombination of oxygen atoms and suppression of ozone generation when the plasma-forming gas contains water vapor is established.

  16. Decomposition of toluene in a steady-state atmospheric-pressure glow discharge

    Science.gov (United States)

    Trushkin, A. N.; Grushin, M. E.; Kochetov, I. V.; Trushkin, N. I.; Akishev, Yu. S.

    2013-02-01

    Results are presented from experimental studies of decomposition of toluene (C6H5CH3) in a polluted air flow by means of a steady-state atmospheric pressure glow discharge at different water vapor contents in the working gas. The experimental results on the degree of C6H5CH3 removal are compared with the results of computer simulations conducted in the framework of the developed kinetic model of plasma chemical decomposition of toluene in the N2: O2: H2O gas mixture. A substantial influence of the gas flow humidity on toluene decomposition in the atmospheric pressure glow discharge is demonstrated. The main mechanisms of the influence of humidity on C6H5CH3 decomposition are determined. The existence of two stages in the process of toluene removal, which differ in their duration and the intensity of plasma chemical decomposition of C6H5CH3 is established. Based on the results of computer simulations, the composition of the products of plasma chemical reactions at the output of the reactor is analyzed as a function of the specific energy deposition and gas flow humidity. The existence of a catalytic cycle in which hydroxyl radical OH acts a catalyst and which substantially accelerates the recombination of oxygen atoms and suppression of ozone generation when the plasma-forming gas contains water vapor is established.

  17. Corona Glow Discharge Plasma Treatment for Hidrophylicity Improvement of Polyester and Cotton Fabrics

    Science.gov (United States)

    Susan, A. I.; Widodo, M.; Nur, M.

    2017-07-01

    The effects of irradiation by a corona glow discharge plasma on hidrophylicity properties of polyester and cotton fabrics were investigated. We used a corona glow discharge plasma reactor with multiple points to plane electrodes, which was generated by a high voltage DC. Factors that affect the hidrophylicity properties were identified and evaluated as functions of irradiation parameters, which include duration of treatment, distance between electrodes, and bias voltage. It was readily observed from SEM examinations that plasma changed the surface morphology of both polyester and cotton fibers, giving result to an increased roughness to both of them. Results also showed that the hidrophylicityof polyester and cotton fabrics improved by the treatment, which is proportional to the time of treatment and voltage, but inversely proportional to the distance between electrodes. Time of treatment that provided the optimum enhancement of hidrophylicity for cotton is 15 minutes which improved the wetting time from 8.16 seconds to 1.26 seconds. For polyester, it took 15 minutes of irradiation time to improve the wetting time from 7340 seconds to 2905 seconds. The optimum distance between electrodes for both fabrics in this study was found to be 2 cm. Further analysis showed that the improved hidrophylicity properties is due to the creation of surface radicals by free radicals in the plasma leading to the formation of new water-attracting functional groups on the fiber surface.

  18. The nonlocal electron kinetics for a low-pressure glow discharge dusty plasma

    Science.gov (United States)

    Liang, Yonggan; Wang, Ying; Li, Hui; Tian, Ruihuan; Yuan, Chengxun; Kudryavtsev, A. A.; Rabadanov, K. M.; Wu, Jian; Zhou, Zhongxiang; Tian, Hao

    2018-05-01

    The nonlocal electron kinetic model based on the Boltzmann equation is developed in low-pressure argon glow discharge dusty plasmas. The additional electron-dust elastic and inelastic collision processes are considered when solving the kinetic equation numerically. The orbital motion limited theory and collision enhanced collection approximation are employed to calculate the dust surface potential. The electron energy distribution function (EEDF), effective electron temperature Teff, and dust surface potential are investigated under different plasma and dust conditions by solving the Boltzmann and the dust charging current balance equations self-consistently. A comparison of the calculation results obtained from nonlocal and local kinetic models is made. It is shown that the appearance of dust particles leads to a deviation of the EEDF from its original profile for both nonlocal and local kinetic models. With the increase in dust density and size, the effective electron temperature and dust surface potential decrease due to the high-energy electron loss on the dust surface. Meanwhile, the nonlocal and local results differ much from each other under the same calculation condition. It is concluded that, for low-pressure (PR ≤ 1 cm*Torr) glow discharge dusty plasmas, the existence of dust particles will amplify the difference of local and nonlocal EEDFs, which makes the local kinetic model more improper to determine the main parameters of the positive column. The nonlocal kinetic model should be used for the calculation of the EEDFs and dusty plasma parameters.

  19. Irradiation of silver and agar/silver nanoparticles with argon, oxygen glow discharge plasma, and mercury lamp.

    Science.gov (United States)

    Ahmad, Mahmoud M; Abdel-Wahab, Essam A; El-Maaref, A A; Rawway, Mohammed; Shaaban, Essam R

    2014-01-01

    The irradiation effect of argon, oxygen glow discharge plasma, and mercury lamp on silver and agar/silver nanoparticle samples is studied. The irradiation time dependence of the synthesized silver and agar/silver nanoparticle absorption spectra and their antibacterial effect are studied and compared. In the agar/silver nanoparticle sample, as the irradiation time of argon glow discharge plasma or mercury lamp increases, the peak intensity and the full width at half maximum, FWHM, of the surface plasmon resonance absorption band is increased, however a decrease of the peak intensity with oxygen glow plasma has been observed. In the silver nanoparticle sample, as the irradiation time of argon, oxygen glow discharge plasma or mercury lamp increases, the peak intensity of the surface plasmon resonance absorption band is increased, however, there is no significant change in the FWHM of the surface plasmon resonance absorption band. The SEM results for both samples showed nanoparticle formation with mean size about 50 nm and 40 nm respectively. Throughout the irradiation time with the argon, oxygen glow discharge plasma or mercury lamp, the antibacterial activity of several kinds of Gram-positive and Gram-negative bacteria has been examined.

  20. Diagnosis of the local thermal equilibrium by optical emission spectroscopy in the evolution of electric discharge

    International Nuclear Information System (INIS)

    Valdivia B, R.; Pacheco S, J.; Pacheco P, M.; Ramos F, F.; Cruz A, A.; Velazquez P, S.

    2008-01-01

    In this work applies the technique of optical emission spectroscopy to diagnose the temperature of the species generated in plasma in the transition to glow discharge arc. Whit this diagnosis is possible to determine the local thermal equilibrium conditions of the discharge. (Author)

  1. DC Glow Discharge Plasma, Containing Dust Particles: Self Organization and Peculiarities of Behavior

    International Nuclear Information System (INIS)

    Molotkov, V.I.; Pustyl'nik, M.Y.; Torchinskij, V.M.; Fortov, V.E.

    2003-01-01

    Dust particles, immersed in a plasma, acquire charge due to which they may be electrostatically trapped in a plasma. The energy of the interaction of the dust particles may be enough to transfer the dust component to nonideal and even crystalline state. This phenomenon is observed in various plasmas. In the present work a review of the investigations of strongly nonideal dusty plasma of the dc glow discharge striations is given. The formation of plasma crystals, liquids and plasma liquid crystals is considered. Typical phenomenon a for the dc discharge dusty plasma, such as coexistence of different phases in a single structure, convective motions, dust acoustic instability, are underlined. Results of the experiments on different external influences on dusty plasma structures are stated. It is shown that external influences may be used for measuring of the particle charge and field of forces acting on a dust grain levitating in a plasma. (author)

  2. Surface modification by preparation of buffer zone in glow-discharge plasma

    International Nuclear Information System (INIS)

    Cho, D.L.

    1986-01-01

    Reactive species, energetic particles, and uv radiation in the plasma created by a glow discharge strongly interact with solid surfaces under the influence of the plasma. As a result of the strong interaction, various physical and chemical reactions, unique and advantageous for the surface modification of solid materials, occur on the solid surfaces. The surface modification is carried out through formation of a thin buffering layer on the solid surface. The preparation of a buffer zone on solid surfaces for surface modification is described. Two kinds of a buffer zone are prepared by plasma polymerization, or simultaneous sputter deposition of electrode material with plasma polymerization: a transitional buffer zone and a graded buffer zone. Important factors for preparation of the buffer zone (pre-conditioning of a substrate surface, thin-film deposition, post-treatment of the film, magnetron discharge, energy input, geometry of a substrate and a plasma) are discussed

  3. Rydberg gas theory of a glow discharge plasma: I. Application to the electrical behaviour of a fast flowing glow discharge plasma.

    Science.gov (United States)

    Mason, Rod S; Mitchell, David J; Dickinson, Paul M

    2010-04-21

    Current-voltage (I-V) curves have been measured, independent of the main discharge, for electricity passing through the steady state fast flowing 'afterglow' plasma of a low power dc glow discharge in Ar. Voltage profiles along the axial line of conduction have been mapped using fixed probes and potentiometry, and the mass spectra of cations emerging from the downstream sampling Cone, also acting as a probe anode, were recorded simultaneously. Floating double probe experiments were also carried out. The electrical behavior is consistent with the well established I-V characteristics of such discharges, but does not comply with classical plasma theory predictions. The plasma decays along the line of conduction, with a lifetime of approximately 1 ms, despite carrying a steady state current, and its potential is below that of the large surface area anode voltage; a situation which cannot exist in the presence of a conventional free ion-electron plasma, unless the electron temperature is super cold. Currents, large by comparison with the main discharge current, and independent of it, are induced to flow through the downstream plasma, from the Anode (acting as a cathode) to the anodic ion exit Cone, induced by electron impact ionisation at the anode, but without necessarily increasing the plasma density. It appears to be conducted by direct charge transfer between a part of the anode surface (acting as cathode to the auxiliary circuit) and the plasma, without secondary electron emission or heating, which suggests the direct involvement of Rydberg atom intermediates. The reaction energy defect (= the work function of the electrode surface) fits with the plasma potential threshold observed for the cathodic reaction to occur. A true free ion-electron plasma is readily detected by the observation of cations at the anode surface, when induced at the downstream anode, at high bias voltages, by the electron impact ionisation in the boundary region. In contrast to the classical

  4. DC negative corona discharge in atmospheric pressure helium: transition from the corona to the ‘normal’ glow regime

    International Nuclear Information System (INIS)

    Hasan, Nusair; Farouk, Bakhtier; Antao, Dion S

    2014-01-01

    Direct current (dc) negative corona discharges in atmospheric pressure helium are simulated via detailed numerical modeling. Simulations are conducted to characterize the discharges in atmospheric helium for a pin plate electrode configuration. A self-consistent two-dimensional hybrid model is developed to simulate the discharges and the model predictions are validated with experimental measurements. The discharge model considered consists of momentum and energy conservation equations for a multi-component (electrons, ions, excited species and neutrals) gas mixture, conservation equations for each component of the mixture and state relations. A drift–diffusion approximation for the electron and the ion fluxes is used. A model for the external circuit driving the discharge is also considered and solved along with the discharge model. Many of the key features of a negative corona discharge, namely non-linear current–voltage characteristics, spatially flat cathode current density and glow-like discharge in the high current regime are displayed in the predictions. A transition to the ‘normal’ glow discharge from the corona discharge regime is also observed. The transition is identified from the calculated current–voltage characteristic curve and is characterized by the radial growth of the negative glow and the engulfment of the cathode wire. (paper)

  5. An influence of ion and sputtered atom flows inhomogeneity on time evolution of the target surface relief in glow discharge

    International Nuclear Information System (INIS)

    Bondarenko, G G; Kristya, V I

    2008-01-01

    A mathematical model of ion and sputtered atom transport in the vicinity of the target with a periodical surface relief in glow discharge in pure gas is developed. Under the assumption that the relief amplitude is small, analytical expressions for their flows are found by the perturbation method and an equation describing the relief amplitude time evolution is derived. It is shown that intensity of sputtering exceeds intensity of sputtered material re-deposition at the relief tops, and relief smoothing always takes place in the process of homogeneous target treatment in glow discharge in pure gas

  6. The hydrogen and oxygen content of self-supporting carbon foils prepared by dc glow discharge in ethylene

    International Nuclear Information System (INIS)

    Tait, N.R.S.; Tolfree, D.W.L.; John, P.; Odeh, I.M.; Thomas, M.J.K.; Tricker, M.J.; Wilson, J.J.B.; England, J.B.A.; Newton, D.

    1980-01-01

    The hydrogen and oxygen content of self-supporting carbon films produced by dc glow discharge have been determined using a precise method involving the elastic scattering of 25 MeV α-particles. The number of carbon-hydrogen bonds has been determined for similar samples using infrared spectroscopy. The results are compared with those for samples made by the carbon arc process. Assuming that the glow discharge carbon contains graphitic regions surrounded by amorphous tetrahedrally bonded material to which hydrogen can attach, a simple estimate is made of the relative numbers of carbon atoms in the two forms. (orig.)

  7. Transition rate diagrams and excitation of titanium in a glow discharge in argon and neon

    Science.gov (United States)

    Weiss, Zdeněk; Steers, Edward B. M.; Pickering, Juliet C.

    2018-06-01

    Emission spectra of titanium in a Grimm-type glow discharge in argon and neon were studied using the formalism of transition rate diagrams. Ti I spectra in argon and neon discharges are similar, without signs of selective excitation, and populations of Ti I levels exhibit a decreasing trend as function of energy, except for some scatter. A major excitation process of Ti II in argon discharge is charge transfer from argon ions to neutral titanium. In neon discharge, a strong selective excitation was observed of Ti II levels at ≈13.3-13.4 eV relative to the Ti I ground state. It was attributed to charge transfer from doubly charged titanium ions to neutral titanium, while the Ti++ ions are produced by charge transfer and ionization of neutral titanium by neon ions. Cascade excitation is important for Ti II levels up to an energy of ≈13 eV relative to the Ti I ground state, both in argon and neon discharges.

  8. Re-design of ITER Glow Discharge Cleaning system based on a fixed electrode concept

    International Nuclear Information System (INIS)

    Yang, Y.; Maruyama, S.; Kiss, G.; O’Connor, M.; Zhang, Y.; Pitts, R.A.; Shimada, M.; Fang, T.; Wang, Y.; Wang, M.; Pan, Y.; Li, B.; Li, L.

    2014-01-01

    Highlights: •This paper summarizes the approved new design of ITER GDC. •It is based on the fixed electrode design instead of the previous movable concept. •Estimates were made on the glow current density. •R and D topics on initiation, steady state and heat load were presented. •Other relevant considerations were listed in an exhaustive manner. -- Abstract: A new design of ITER Glow Discharge Cleaning (GDC) system based on a fixed electrode concept replaces the previous design which was based on a movable electrode integrated with the ITER In-Vessel-Viewing-System. Recently the conceptual design of the GDC system was reviewed successfully on the functions, safety, operation and maintenance. The design proposed was checked against the requirements and found to be feasible. This paper gives an overall description of the requirements from physics and operation viewpoints and introduces the design at the conceptual level. Main R and D activities are listed and summarized. Further detailed studies are to be performed in the following design stage

  9. Carbon dioxide reforming of methane by atmospheric pressure pulsed glow discharge: The effect of pulse compression

    International Nuclear Information System (INIS)

    Ghorbanzadeh, A.; Modarresi, H.

    2006-01-01

    Methane reforming by carbon dioxide in atmospheric pressure pulsed glow discharge was examined. The pulse duration of plasma was compressed to ∼50 ns or lower. This compression allowed working at higher frequencies, more than 3 k Hz, without glow to arc transition. The main outlet gases were synthetic gases (H 2 , CO) and C 2 (ethylene, ethane, and acetylene) products. At equal reactants proportion CO 2 /CH 4 =1, about 42 p ercent o f plasma energy went to chemical dissociation while reactant conversions were relatively high, i.e. near 55 p ercent % (CH 4 ) and 42 p ercent ( CO 2 ). At this point, the energy expenditure was less than 3.8 eV per each converted molecule. The reactor energy performance even gets better at higher CO 2 /CH 4 proportions. At CO 2 /CH 4 =5, The conversions of about 65 p ercent a nd 45 p ercent w ere obtained for methane and carbon dioxide respectively, while energy efficiency reached near 45 p ercent . It is discussed that high nonequilibrium state of vibrational energy at short pulses, especially in carbon dioxide, leads to this improvement.

  10. Study of a contracted glow in low-frequency plasma-jet discharges operating with argon

    Energy Technology Data Exchange (ETDEWEB)

    Minotti, F.; Giuliani, L.; Xaubet, M.; Grondona, D. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, C1428EHA, Buenos Aires, Argentina and Instituto de Física del Plasma (INFIP), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires - UBA, C1428EHA, Buenos Aires (Argentina)

    2015-11-15

    In this work, we present an experimental and theoretical study of a low frequency, atmospheric plasma-jet discharge in argon. The discharge has the characteristics of a contracted glow with a current channel of submillimeter diameter and a relatively high voltage cathode layer. In order to interpret the measurements, we consider the separate modeling of each region of the discharge: main channel and cathode layer, which must then be properly matched together. The main current channel was modeled, extending a previous work, as similar to an arc in which joule heating is balanced by lateral heat conduction, without thermal equilibrium between electrons and heavy species. The cathode layer model, on the other hand, includes the emission of secondary electrons by ion impact and by additional mechanisms, of which we considered emission due to collision of atoms excited at metastable levels, and field-enhanced thermionic emission (Schottky effect). The comparison of model and experiment indicates that the discharge can be effectively sustained in its contracted form by the secondary electrons emitted by collision of excited argon atoms, whereas thermionic emission is by far insufficient to provide the necessary electrons.

  11. The breakdown and glow phases during the initiation of discharges for lamps

    International Nuclear Information System (INIS)

    Pitchford, L.C.; Peres, I.; Liland, K.B.; Boeuf, J.P.; Gielen, H.

    1997-01-01

    High intensity discharge (HID) lamps are often initiated by the application of one or more short, high-voltage, breakdown pulses superimposed on a 50 or 60 Hz generator voltage. A successful transition from the breakdown event to steady-state operating conditions in HID lamps requires that the lamp-circuit system be adequate to sustain the plasma created during breakdown until the electrodes are heated to thermionic temperatures. In this article, we use a one-dimensional (in the axial direction) transient discharge model to study the conditions needed to sustain the cold-cathode discharge after a breakdown event has occurred. While the application of our one-dimensional model to real lamps is approximate, we find that the model predictions are consistent with experimental results in HID lamps, a few of which are presented here. The main conclusion from this work is that, after breakdown, the voltage necessary to sustain a glow discharge is dependent on the source impedance, the gas composition, and on the plasma density created by the breakdown event. copyright 1997 American Institute of Physics

  12. Surface treatment of polyethylene terephthalate film using atmospheric pressure glow discharge in air

    International Nuclear Information System (INIS)

    Fang Zhi; Qiu Yuchang; Wang Hui

    2004-01-01

    Non-thermal plasmas under atmospheric pressure are of great interest in polymer surface processing because of their convenience, effectiveness and low cost. In this paper, the treatment of Polyethylene terephthalate (PET) film surface for improving hydrophilicity using the non-thermal plasma generated by atmospheric pressure glow discharge (APGD) in air is conducted. The discharge characteristics of APGD are shown by measurement of their electrical discharge parameters and observation of light-emission phenomena, and the surface properties of PET before and after the APGD treatment are studied using contact angle measurement, x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It is found that the APGD is homogeneous and stable in the whole gas gap, which differs from the commonly filamentary dielectric barrier discharge (DBD). A short time (several seconds) APGD treatment can modify the surface characteristics of PET film markedly and uniformly. After 10 s APGD treatment, the surface oxygen content of PET surface increases to 39%, and the water contact angle decreases to 19 degree, respectively. (authors)

  13. Experimental study of the negative glow and cathode sheath of an electron beam discharge

    International Nuclear Information System (INIS)

    Zeller, Philippe

    1988-01-01

    This research thesis reports the study of a middle-pressure (0.1-5 Torr) discharge in which a negative-glow-type plasma is created by a continuous electron beam (1 to 10 keV, 1 to 30 mA/cm 2 ). Such a discharge is characterised by a highly abnormal cathodic drop with a beam generation displaying an electric efficiency close to 1. In a first part, the author presents the main operation characteristics, discharge regimes and emission spectrum, and discusses bibliographical data related to cathode emission processes and to the distribution function of plasma electron velocities. The author then describes an original method of measurement of plasma conductivity. In the next part, he reports the study of the cathode region in which the electron beam generation occurs. The electric field has been measured in this region by using spatially resolved laser opto-galvanic spectroscopy. Results highlight an essentially linear spatial decay of the field. Besides, and based on these results, the author indicates scale laws leading to simple relationships between discharge parameters [fr

  14. Analysis of the neutral drag force in a dc glow discharge dusty plasma

    International Nuclear Information System (INIS)

    Thomas, Edward Jr.; Williams, Jeremiah

    2005-01-01

    In this paper, the authors report on a series of experiments that use carefully applied perturbations to a dust cloud to reproducibly investigate the formation of the microparticle cloud and the formation of dust cloud-plasma interface. Here, one micron diameter alumina microparticles are suspended in an argon dc glow discharge plasma. A perturbing voltage pulse is applied to the cathode, causing a momentary disruption in the confinement of the dust cloud. After the perturbation, the cloud reforms, typically with a central 'mass' and two 'streams' of particles that are flowing into the cloud from both sides. Through the use of stereoscopic particle image velocimetry (stereo-PIV), the complete three-dimensional velocity of the microparticles can be measured. The particles in the streams are used as test particles to characterize the forces acting upon the microparticles. Analysis of the experimental measurements suggests that the effective neutral drag force may be lower than expected

  15. Plasma sheath physics and dose uniformity in enhanced glow discharge plasma immersion ion implantation and deposition

    International Nuclear Information System (INIS)

    Li Liuhe; Li Jianhui; Kwok, Dixon T. K.; Chu, Paul K.; Wang Zhuo

    2009-01-01

    Based on the multiple-grid particle-in-cell code, an advanced simulation model is established to study the sheath physics and dose uniformity along the sample stage in order to provide the theoretical basis for further improvement of enhanced glow discharge plasma immersion ion implantation and deposition. At t=7.0 μs, the expansion of the sheath in the horizontal direction is hindered by the dielectric cage. The electron focusing effect is demonstrated by this model. Most of the ions at the inside wall of the cage are implanted into the edge of the sample stage and a relatively uniform ion fluence distribution with a large peak is observed at the end. Compared to the results obtained from the previous model, a higher implant fluence and larger area of uniformity are disclosed.

  16. True random bit generators based on current time series of contact glow discharge electrolysis

    Science.gov (United States)

    Rojas, Andrea Espinel; Allagui, Anis; Elwakil, Ahmed S.; Alawadhi, Hussain

    2018-05-01

    Random bit generators (RBGs) in today's digital information and communication systems employ a high rate physical entropy sources such as electronic, photonic, or thermal time series signals. However, the proper functioning of such physical systems is bound by specific constrains that make them in some cases weak and susceptible to external attacks. In this study, we show that the electrical current time series of contact glow discharge electrolysis, which is a dc voltage-powered micro-plasma in liquids, can be used for generating random bit sequences in a wide range of high dc voltages. The current signal is quantized into a binary stream by first using a simple moving average function which makes the distribution centered around zero, and then applying logical operations which enables the binarized data to pass all tests in industry-standard randomness test suite by the National Institute of Standard Technology. Furthermore, the robustness of this RBG against power supply attacks has been examined and verified.

  17. Degradation of m-dihydroxybenzene by contact glow discharge electrolysis in aqueous

    International Nuclear Information System (INIS)

    Gai, Ke; Qi, Huili; Ma, Dongping; Wang, Chunlin

    2013-01-01

    This paper reported the degradation of m-dihydroxybenzene aqueous solution with contact Glow Discharge Electrolysis. The rate of degradation in different conditions such as pH, H 2 O 2 , Fe 2+ , methanol, and other affecting factors were studied. The results showed that there is faster removal rate when the solution is in a relatively higher acidity; H 2 O 2 can improve the efficiency rate. Fe 2+ can promote reaction, but radical elimination agent of methanol will decrease the rate of the reaction. On the basis of analyzing the ultraviolet (UV) spectra of the solution and the intermediate products from High Performance Liquid Chromatography-Mass Spectrum (HPLC-MS), reaction pathway was proposed.

  18. Compositional characterisation of rare earth magnet materials by glow discharge quadrupole mass spectrometry

    International Nuclear Information System (INIS)

    Reddy, M.A.; Shekhar, R.; Kumar, Sunil Jai

    2014-01-01

    In this paper, glow discharge quadrupole mass spectrometric (GD-QMS) studies on Sm-Pr-Co compound magnetic materials are reported. The composition of these magnetic materials produced from different manufacturing routes (imported, indigenous) was determined. The results are compared with the results obtained by an alternative analytic technique, inductively coupled plasma atomic emission spectrometry (ICP-AES), after complete dissolution of the material in the appropriate acids. For perfectly homogeneous material both the wet chemical method and direct solid analysis method should give the same result. A close examination of both the results indicates that for imported materials the values obtained by wet chemical method and direct solid method are in close agreement. This indicates that the imported (solid) material is highly homogeneous. For indigenous materials, it shows a large difference in the values of Co and Sm. This reveals that the solid material prepared is not as homogenous as the imported materials

  19. Control of discharge conditions to reduce hydrogen content in low Z films produced with DC glow

    International Nuclear Information System (INIS)

    Natsir, M.; Sagara, A.; Tsuzuki, K.; Tsuchiya, B.; Hasegawa, Y.; Motojima, O.

    1995-09-01

    Boronization at near room temperature has been performed in plasma processing teststand (PPT) by using a 5 % diborane gases B 2 H 6 in He on electrically floating or unfloating Al samples under various conditions on DC glow discharge power or total gas pressure. The hydrogen concentration was analyzed by using elastic recoil detection method (ERD) and a new modified normalizing technique with Rutherford back scattering (RBS). Results showed that a high growth rate of film formation and floating surface were effective in reducing hydrogen concentration in B films. This result was in good agreement with earlier measurements of H with flash filament (FF) desorption method. In particular the H/B ratio was reduced by decreasing ions but increasing radicals for B film formation. (author)

  20. Synthesis of Biodiesel from Crude Palm Oil by Using Contact Glow Discharge Electrolysis

    Science.gov (United States)

    Saksono, Nelson; Aditya Siswosoebrotho, Danar; Pranata, Jeremia J. C.; Bismo, Setijo

    2018-03-01

    This research has evaluated the use of Contact Glow Discharge Electrolysis method in the synthesis of biodiesel. The purpose of this research is to get the synthesis process and biodiesel product. The solution used is the mix of Crude Palm Oil and methanol with molar ratio of 1:24, and catalyst of NaOH and KOH with variation of concentration 0.5% - 1.5%-wt. The result shows that the biodiesel can be made from transesterification reaction that may be initiated by radical methoxide. The use of electrolyte KOH is better than NaOH based on the yield of biodiesel and the energy consumption. The optimum yield reaches 97%, at the synthesis for 30 minutes with the use of KOH 1%-wt with the energy consumption of 1.32 kJ/mL.

  1. Debromination and decomposition of bromoform by contact glow discharge electrolysis in an aqueous solution

    International Nuclear Information System (INIS)

    Wang, Lei; Liu, Panliang; Zhang, Songlin

    2015-01-01

    Bromoform (BF) is a stable and carcinogenic contaminant in water. In this study, efficient debromination and decomposition of BF induced by contact glow discharge electrolysis (CGDE) in a sodium sulfate solution were investigated. Intermediate byproducts were determined by ionic chromatography and gas chromatography, respectively. Experimental results showed that alkaline conditions and additions of organic additives to the solution were favorable for both the removal and the debromination of BF. Oxalic acid, formic acid, dibromomethane and bromate ion were determined as the major intermediate byproducts. Final products were inorganic carbon and bromide ion. Hydrated electrons may be the most likely active species responsible for the initiation of the debromination, and hydroxyl radicals may be the ones for the oxidation of the intermediate byproducts

  2. Raman spectra of amorphous silicon thin films deposited by glow discharge

    International Nuclear Information System (INIS)

    Bustarret, E.; Alvarez, F.; Brenzikofer, R.; Vilche Pena, A.; Chambouleyron, I.

    1983-01-01

    The local disorder present in films of a-Si:H and a-Si sub(x) N 1 - sub(x):H has been studied through first order Raman spectroscopy, using the 5145A line of an Argon laser in a backscattering geometry at room temperature. This allowed us to compare thin films deposited in two different reactors where the capacitively coupled glow-discharge was produced either in a 'cross field' or a 'parallel field' geometry. Gaseous mixtures of SiH 4 , N 2 , He and Ar have been used in both cases. The systematic variation of the preparation parameters leads to a whole class of 'alloys' including partially micro-crystallized films. (Author) [pt

  3. RAMAN spectra of amorphous silicon thin films deposited by glow discharges

    International Nuclear Information System (INIS)

    Bustarret, E.; Alvarez, F.; Brenzikofer, R.; Vilche Pena, A.; Chambouleyron, I.

    1983-01-01

    The local disorder present in films of a-Si:H and a-Si x N 1-x :H has been studied through first order Raman spectroscopy, using the 5145A line of an Argon laser in a backscattering geometry at room temperature. This allowed us to compare thin films deposited in two different reactors where the capacitively coupled glow-discharge was produced either in a ''cross field'' or a ''parallel field'' geometry. Gaseous mixtures of SiH 4 . N 2 , He and Ar have been used in both cases. The systematic variation of the preparation parameters leads to a whole class of ''alloys'' including partially micro-crysttalized films. (author) [pt

  4. Thermal degradation process of poly (alpha-methylstyrene) microspheres coated with glow discharge polymer

    International Nuclear Information System (INIS)

    Zhang Zhanwen; Huang Yong; Tang Yongjian; Li Bo; Chen Sufen; He Zhibing

    2009-01-01

    Glow discharge polymer (GDP) shell was made by the decomposable mandrel technique using poly(alpha-methylstyrene) (PAMS) mandrel. The PAMS degradation rate and the GDP shell surface morphology at different equilibrium temperatures were investigated. Degradation rate was calculated from weight variation of PAMS before and after pyrolysis process. Experiment results indicate that the degradation rate decreases at the fixed equilibrium temperature and graded temperature can improve the rate. The degradation process has an effect on the GDP shell properties. The PAMS doesn't molten to flow liquid during degradation. But the degradation can reduce surface finish of GDP coatings. The GDP shell deffects are the result of the PAMS degradiation process. (authors)

  5. Dusty plasma in a glow discharge in helium in temperature range of 5–300 K

    Energy Technology Data Exchange (ETDEWEB)

    Samoilov, I. S.; Baev, V. P.; Timofeev, A. V., E-mail: timofeevalvl@gmail.com; Amirov, R. Kh.; Kirillin, A. V.; Nikolaev, V. S.; Bedran, Z. V. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2017-03-15

    Dusty plasma structures in glow discharge in helium in the temperature range of 5–300 K are investigated experimentally. We have described the experimental setup that makes it possible to continuously vary the temperature regime. The method for experimental data processing has been described. We have measured interparticle distances in the temperature range of 9–295 K and compared them with the Debye radius. We indicate the ranges of variations in experimental parameters in which plasma–dust structures are formed and various types of their behavior are manifested (rotation, vibrations of structures, formation of vertical linear chains, etc.). The applicability of the Yukawa potential to the description of the structural properties of a dusty plasma in the experimental conditions is discussed.

  6. Periodic long-range transport in a large volume dc glow discharge dusty plasma

    International Nuclear Information System (INIS)

    Thomas, Edward Jr.; Amatucci, William E.; Compton, Christopher; Christy, Brian; Jackson, Jon David

    2003-01-01

    In an earlier paper, the authors reported on observations of a variety of particle transport phenomena observed in DUPLEX--the DUsty PLasma EXperiment at the Naval Research Laboratory [E. Thomas, Jr., W. E. Amatucci, C. Compton, and B. Christy, Phys. Plasmas 9, 3154 (2002)]. DUPLEX is a large, transparent polycarbonate cylinder that is 40 cm in radius and 80 cm in height. dc glow discharge argon plasmas are generated in DUPLEX. In this paper, the authors expand upon one particular feature of particle transport in DUPLEX, the long-range (i.e., greater than 15 cm), periodic (T∼2.5 min) transport of suspended alumina particles through the plasma. A detailed description of this particle motion through the plasma is presented. Finally, a qualitative model describing the phenomena that lead to this transport is also given

  7. Nonlinear time-series analysis of current signal in cathodic contact glow discharge electrolysis

    International Nuclear Information System (INIS)

    Allagui, Anis; Abdelkareem, Mohammad Ali; Rojas, Andrea Espinel; Bonny, Talal; Elwakil, Ahmed S.

    2016-01-01

    In the standard two-electrode configuration employed in electrolytic process, when the control dc voltage is brought to a critical value, the system undergoes a transition from conventional electrolysis to contact glow discharge electrolysis (CGDE), which has also been referred to as liquid-submerged micro-plasma, glow discharge plasma electrolysis, electrode effect, electrolytic plasma, etc. The light-emitting process is associated with the development of an irregular and erratic current time-series which has been arbitrarily labelled as “random,” and thus dissuaded further research in this direction. Here, we examine the current time-series signals measured in cathodic CGDE configuration in a concentrated KOH solution at different dc bias voltages greater than the critical voltage. We show that the signals are, in fact, not random according to the NIST SP. 800-22 test suite definition. We also demonstrate that post-processing low-pass filtered sequences requires less time than the native as-measured sequences, suggesting a superposition of low frequency chaotic fluctuations and high frequency behaviors (which may be produced by more than one possible source of entropy). Using an array of nonlinear time-series analyses for dynamical systems, i.e., the computation of largest Lyapunov exponents and correlation dimensions, and re-construction of phase portraits, we found that low-pass filtered datasets undergo a transition from quasi-periodic to chaotic to quasi-hyper-chaotic behavior, and back again to chaos when the voltage controlling-parameter is increased. The high frequency part of the signals is discussed in terms of highly nonlinear turbulent motion developed around the working electrode.

  8. Alteration of five organic compounds by glow discharge plasma and UV light under simulated Mars conditions

    Science.gov (United States)

    Hintze, Paul E.; Buhler, Charles R.; Schuerger, Andrew C.; Calle, Luz M.; Calle, Carlos I.

    2010-08-01

    The Viking missions to Mars failed to detect any organic material in regolith samples. Since then, several removal mechanisms of organic material have been proposed. Two of these proposed methods are removal due to exposure to plasmas created in dust devils and exposure to UV irradiation. The experiments presented here were performed to identify similarities between the two potential removal mechanisms and to identify any compounds produced from these mechanisms that would have been difficult for the Viking instruments to detect. Five organic compounds, phenanthrene, octadecane, octadecanoic acid, decanophenone and benzoic acid, were exposed to a glow discharge plasma created in simulated martian atmospheres as might be present in dust devils, and to UV irradiation similar to that found at the surface of Mars. Glow discharge exposure was carried out in a chamber with 6.9 mbar pressure of a Mars like gas composed mostly of carbon dioxide. The plasma was characterized using emission spectroscopy and found to contain cations and excited neutral species including carbon dioxide, carbon monoxide, and nitrogen. UV irradiation experiments were performed in a Mars chamber which simulates the temperature, pressure, atmospheric composition, and UV fluence rates of equatorial Mars. The non-volatile residues left after each exposure were characterized by mass loss, infrared spectroscopy and high resolution mass spectrometry. Oxidized, higher molecular weight versions of the parent compounds containing carbonyl, hydroxyl and alkenyl functional groups were identified. The presence of these oxidized compounds suggests that searches for organic material in soils on Mars use instrumentation suitable for detection of compounds which contain the above functional groups. Discussions of possible reaction mechanisms are given.

  9. Surface modification of polyimide (PI) film using water cathode atmospheric pressure glow discharge plasma

    International Nuclear Information System (INIS)

    Zheng Peichao; Liu Keming; Wang Jinmei; Dai Yu; Yu Bin; Zhou Xianju; Hao Honggang; Luo Yuan

    2012-01-01

    Highlights: ► Equipment called water cathode atmospheric pressure glow discharge was used to improve the hydrophilicity of polyimide films. ► The data shows good homogeneity and the variation trends of contact angles are different for polar and non-polar testing liquids. ► The thickness of liquid layer plays an important role in plasma processing and directly affects the treatment effect. ► Surface hydrophilicity after plasma treatment is improved partly due to the increase in the roughness. ► The hydrophilicity of polyimide films is still better than untreated ones after long-term storage. - Abstract: The industrial use of polyimide film is limited because of undesirable properties such as poor wettability. In the present paper, a new kind of equipment called water cathode atmospheric pressure glow discharge was used to improve the surface properties of polyimide films and made them useful to technical applications. The changes in hydrophilicity of modified polyimide film surfaces were investigated by contact angle, surface energy and water content measurements as a function of treatment time. The results obtained show good treatment homogeneity and that the variation trends of contact angles are different for polar and non-polar testing liquids, while surface energy and water content are significantly enhanced with the increase of treatment time until they achieve saturated values after 60 s plasma treatment. Also, the thickness of liquid layer plays an important role in plasma processing and directly affects the treatment effect. Changes in morphology of polyimide films were analyzed by atomic force microscope and the results indicate that surface hydrophilicity after plasma treatment are improved partly due to the increase in the roughness. In addition, polyimide films treated by plasma are subjected to an ageing process to determine the durability of plasma treatment. It is found that the hydrophilicity is still better than untreated ones though the

  10. Positive column of a glow discharge in neon with charged dust grains (a review)

    Energy Technology Data Exchange (ETDEWEB)

    Polyakov, D. N., E-mail: cryolab@ihed.ras.ru; Shumova, V. V.; Vasilyak, L. M. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2017-03-15

    The effect of charged micron-size dust grains (microparticles) on the electric parameters of the positive column of a low-pressure dc glow discharge in neon has been studied experimentally and numerically. Numerical analysis is carried out in the diffusion-drift approximation with allowance for the interaction of dust grains with metastable neon atoms. In a discharge with a dust grain cloud, the longitudinal electric field increases. As the number density of dust grains in an axisymmetric cylindrical dust cloud rises, the growth of the electric field saturates. It is shown that the contribution of metastable atoms to ionization is higher in a discharge with dust grains, in spite of the quenching of metastable atoms on dust grains. The processes of charging of dust grains and the dust cloud are considered. As the number density of dust grains rises, their charge decreases, while the space charge of the dust cloud increases. The results obtained can be used in plasma technologies involving microparticles.

  11. Positive column of a glow discharge in neon with charged dust grains (a review)

    International Nuclear Information System (INIS)

    Polyakov, D. N.; Shumova, V. V.; Vasilyak, L. M.

    2017-01-01

    The effect of charged micron-size dust grains (microparticles) on the electric parameters of the positive column of a low-pressure dc glow discharge in neon has been studied experimentally and numerically. Numerical analysis is carried out in the diffusion-drift approximation with allowance for the interaction of dust grains with metastable neon atoms. In a discharge with a dust grain cloud, the longitudinal electric field increases. As the number density of dust grains in an axisymmetric cylindrical dust cloud rises, the growth of the electric field saturates. It is shown that the contribution of metastable atoms to ionization is higher in a discharge with dust grains, in spite of the quenching of metastable atoms on dust grains. The processes of charging of dust grains and the dust cloud are considered. As the number density of dust grains rises, their charge decreases, while the space charge of the dust cloud increases. The results obtained can be used in plasma technologies involving microparticles.

  12. Effects of time-temperature profiles on glow curves of germanium-doped optical fibre

    Science.gov (United States)

    Lam, S. E.; Alawiah, A.; Bradley, D. A.; Mohd Noor, N.

    2017-08-01

    The Germanium (Ge) doped silica optical fibres have demonstrated the great potential to be developed as a thermoluminescent (TL) dosimeter that can be used in various applications in radiotherapy, diagnostic radiology, UV dosimetry system and food irradiation industry. Different time-temperature profile (TTP) parameters of the TL reader have been employed by many researchers in various of TL studies. Nevertheless, none of those studies adequately addressed the effects of the reader's preheat temperature and heating rate on the kinetic parameters of the TL glow curve specifically, the Ge-doped silica optical fibres. This research addresses the issue of TTP parameters with special attention to the determination of the kinetic parameters of the glow curve. The glow curve responses were explored and the kinetic parameters were analyzed by the WinGCF software, to show the effect of the preheat temperature and heating rate of the reader on Ge-doped fibre irradiated with 18 Gy of 6 MV photons radiation. The effect of TTP parameters was discussed and compared against the commercial fibre and tailored made fibre of 6 mol% Ge-doped of flat and cylindrical shape. The deconvolution of glow peaks and the kinetic parameters were obtained by the WinGCF software. This enables to fit accurately (1.5%glow curves. A positive, moderate linear relationship exists between the TL response and the heating rate when the specific preheat temperature was used to read commercial fibre (50 °C) and cylindrical fibre (80 °C and 160 °C). It is found that the glow peaks of cylindrical fibre exhibit the highest peak integral as compared to flat and commercial fibres. This study revealed the possible relationship between the reader's TTP parameters and the kinetic parameters of TL glow curves for the commercial and tailored made Ge-doped silica optical fibres.

  13. Two discharge modes of a repetitive nanosecond pulsed helium glow discharge under sub-atmospheric pressure in the repetition frequency range of 20 to 600 kHz

    Science.gov (United States)

    Kikuchi, Yusuke; Maegawa, Takuya; Otsubo, Akira; Nishimura, Yoshimi; Nagata, Masayoshi; Yatsuzuka, Mitsuyasu

    2018-05-01

    Two discharge modes, α and γ, of a repetitive nanosecond pulsed helium glow discharge at a gas pressure of 10 kPa in the repetition frequency range from 20 to 600 kHz are reported for the first time. The pulsed glow discharge is produced in a pair of parallel plate metal electrodes without insertion of dielectrics. The α mode discharge is volumetrically produced in the electrode gap at a low-repetition frequency, whereas the γ mode discharge is localized at the cathode surface at a high-repetition frequency. At high-repetition frequency, the time interval between voltage pulses is shorter than the lifetime of the afterglow produced by the preceding discharge. Then, the γ mode discharge is maintained by a large number of secondary electrons emitted from the cathode exposed to high-density ions and metastable helium atoms in the afterglow. In the α mode discharge with a low-repetition frequency operation, primary electrons due to gas ionization dominate the ionization process. Thus, a large discharge voltage is needed for the excitation of the α mode discharge. It is established that the bifurcation of α-γ discharge mode, accompanied by a decrease in the discharge voltage, occurs at the high-repetition frequency of ∼120 kHz.

  14. Role of cathode identity in liquid chromatography particle beam glow discharge mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Krishna, M.V. Balarama [Department of Chemistry, Biosystems Research Complex, Clemson University, Clemson, SC 29634-1905 (United States); Marcus, R.K. [Department of Chemistry, Biosystems Research Complex, Clemson University, Clemson, SC 29634-1905 (United States)], E-mail: marcusr@clemson.edu

    2008-06-15

    A detailed evaluation of the role of cathode identity on the analytical and spectral characteristics of various organic, organometallic and metal analytes using liquid chromatography-particle beam/glow discharge mass spectrometry (LC-PB/GDMS) has been carried out. A d.c. discharge, operating with argon as the support gas, was used throughout this work. In this study, Cu which has a relatively high sputtering rate, Ni which has moderate sputtering rate and Ta which has very low sputtering rate, are taken as cathode materials to study the ionization, fragmentation, and analytical characteristics of organic (caffeine, epigallocatechin gallate, peptide as representative compounds), organometallic (selenomethionine, triethyl lead chloride as representative compounds) and metal (Fe, La, Cs and Pb) species. A range of discharge gas pressures (26.6-106.4 Pa) and currents (0.2-1.5 mA) were investigated with the test cathodes to determine their influence on the spectral composition and overall analytical response for the various test species. Calibration plots were obtained for all of the species for each of the three cathodes to determine the respective limits of detection. Relative detection limits in the range of 0.02 to 15 ng mL{sup -1} (0.002-1.5 ng, absolute) for the test species were found to be in the order of Cu > Ni > Ta; which follows the order of the sputtering characteristics of the respective cathodes. These studies rendered information about the respective discharge parameters' role in choosing the most appropriate cathode identity in PB-GDMS for application in the areas of organic, organometallic and inorganic species analysis.

  15. Baking and helium glow discharge cleaning of SST-1 tokamak with graphite plasma facing components

    International Nuclear Information System (INIS)

    Semwal, Pratibha; Khan, Ziauddin; Raval, Dilip

    2015-01-01

    Graphite plasma facing components (PFCs) were installed inside SST-1 vacuum vessel. Prior to installation, all the graphite tiles were baked at 1000 °C in a vacuum furnace operated below 1.0 X 10 -5 mbar. However due to the porous structure of graphite, they absorb a significant amount of water vapour from air during the installation process. Rapid desorption of water vapour requires high temperature bake-out of the PFCs at ≥ 250 °C. In SST-1 the PFCs were baked at 250 °C using hot nitrogen gas facility to remove the absorbed water vapour. Also device with large graphite surface area has the disadvantage that a large quantity of hydrogen gets trapped inside it during plasma discharges which makes density control difficult. Helium (He) glow discharge cleaning (GDC) effectively removes this stored hydrogen as well as other impurities like oxygen and hydrocarbon within few nanometers from the surface by particle induced desorption. Before plasma operation in SST-1 tokamak, both baking of PFCs and He-GDC were carried out so that these impurities were removed effectively. The mean desorption yield of hydrogen was found to be 0.48. In this paper, the results of effect of baking and He-GDC experiments of SST-1 will be presented in detail. (author)

  16. Baking and helium glow discharge cleaning of SST-1 Tokamak with graphite plasma facing components

    International Nuclear Information System (INIS)

    Semwal, P; Khan, Z; Raval, D C; Dhanani, K R; George, S; Paravastu, Y; Prakash, A; Thankey, P; Ramesh, G; Khan, M S; Saikia, P; Pradhan, S

    2017-01-01

    Graphite plasma facing components (PFCs) were installed inside the SST-1 vacuum vessel. Prior to installation, all the graphite tiles were baked at 1000 °C in a vacuum furnace operated below 1.0 × 10 -5 mbar. However due to the porous structure of graphite, they absorb a significant amount of water vapour from air during the installation process. Rapid desorption of this water vapour requires high temperature bake-out of the PFCs at ≥ 250 °C. In SST-1 the PFCs were baked at 250 °C using hot nitrogen gas facility to remove the absorbed water vapour. Also device with large graphite surface area has the disadvantage that a large quantity of hydrogen gets trapped inside it during plasma discharges which makes density control difficult. Helium glow discharge cleaning (He-GDC) effectively removes this stored hydrogen as well as other impurities like oxygen and hydrocarbon within few nano-meters from the surface by particle induced desorption. Before plasma operation in SST-1 tokamak, both baking of PFCs and He-GDC were carried out so that these impurities were removed effectively. The mean desorption yield of hydrogen was found to be 0.24. In this paper the results of baking and He-GDC experiments of SST-1 will be presented in detail. (paper)

  17. Baking and helium glow discharge cleaning of SST-1 Tokamak with graphite plasma facing components

    Science.gov (United States)

    Semwal, P.; Khan, Z.; Raval, D. C.; Dhanani, K. R.; George, S.; Paravastu, Y.; Prakash, A.; Thankey, P.; Ramesh, G.; Khan, M. S.; Saikia, P.; Pradhan, S.

    2017-04-01

    Graphite plasma facing components (PFCs) were installed inside the SST-1 vacuum vessel. Prior to installation, all the graphite tiles were baked at 1000 °C in a vacuum furnace operated below 1.0 × 10-5 mbar. However due to the porous structure of graphite, they absorb a significant amount of water vapour from air during the installation process. Rapid desorption of this water vapour requires high temperature bake-out of the PFCs at ≥ 250 °C. In SST-1 the PFCs were baked at 250 °C using hot nitrogen gas facility to remove the absorbed water vapour. Also device with large graphite surface area has the disadvantage that a large quantity of hydrogen gets trapped inside it during plasma discharges which makes density control difficult. Helium glow discharge cleaning (He-GDC) effectively removes this stored hydrogen as well as other impurities like oxygen and hydrocarbon within few nano-meters from the surface by particle induced desorption. Before plasma operation in SST-1 tokamak, both baking of PFCs and He-GDC were carried out so that these impurities were removed effectively. The mean desorption yield of hydrogen was found to be 0.24. In this paper the results of baking and He-GDC experiments of SST-1 will be presented in detail.

  18. Conditioning of SST-1 Tokamak Vacuum Vessel by Baking and Glow Discharge Cleaning

    International Nuclear Information System (INIS)

    Khan, Ziauddin; George, Siju; Semwal, Pratibha; Dhanani, Kalpeshkumar R.; Pathan, Firozkhan S.; Paravastu, Yuvakiran; Raval, Dilip C.; Babu, Gattu Ramesh; Khan, Mohammed Shoaib; Pradhan, Subrata

    2016-01-01

    Highlights: • SST-1 Tokamak was successfully commissioned. • Vacuum vessel was pumped down to 4.5 × 10"–"8 mbar after baking and continuous GDC. • GDC reduced the water vapour by additional 57% while oxygen was reduced by 50%. • Under this condition, an initial plasma breakdown with current of 40 kA for 75 ms was achieved. - Abstract: Steady-state Superconducting Tokamak (SST-1) vacuum vessel (VV) adopts moderate baking at 110 ± 10 °C and the limiters baking at 250 ± 10 °C for ∼ 200 h followed by glow discharge cleaning in hydrogen (GDC-H) with 0.15 A/m"2 current density towards its conditioning prior to plasma discharge experiment. The baking in SST-1 reduces the water (H_2O) vapor by 95% and oxygen (O_2) by 60% whereas the GDC reduces the water vapor by an additional 57% and oxygen by another 50% as measured with residual gas analyzer. The minimum breakdown voltage for H-GDC in SST-1 tokamak was experimentally observed to 300 V at 8 mbar cm. As a result of these adherences, SST-1 VV achieves an ultimate of 4.5 × 10"−"8 mbar with two turbo-molecular pumps with effective pumping speed of 3250 l/s. In the last campaign, SST-1 has achieved successful plasma breakdown, impurity burn through and a plasma current of ∼ 40 kA for 75 ms.

  19. Studies on gas breakdown in pulsed radio frequency atmospheric pressure glow discharges

    International Nuclear Information System (INIS)

    Huo, W. G.; Jian, S. J.; Yao, J.; Ding, Z. F.

    2014-01-01

    In pulsed RF atmospheric pressure glow discharges, the gas breakdown judged by the rapid drop in the amplitude of the pulsed RF voltage is no longer universally true. The steep increment of the plasma-absorbed RF power is proposed to determine the gas breakdown. The averaged plasma-absorbed RF power over a pulse period is used to evaluate effects of the preceding pulsed RF discharge on the breakdown voltage of the following one, finding that the breakdown voltage decreases with the increment in the averaged plasma-absorbed RF power under constant pulse duty ratio. Effects of the pulse off-time on the breakdown voltage and the breakdown delay time are also studied. The obtained dependence of the breakdown voltage on the pulse off-time is indicative of the transitional plasma diffusion processes in the afterglow. The breakdown voltage varies rapidly as the plasma diffuses fast in the region of moderate pulse off-time. The contribution of nitrogen atom recombination at the alumina surface is demonstrated in the prolonged memory effect on the breakdown delay time vs. the pulse off-time and experimentally validated by introducing a trace amount of nitrogen into argon at short and long pulse off-times

  20. A kinetic model for low pressure glow discharges in the presence of dust particles

    International Nuclear Information System (INIS)

    Wang Dezhen; Dong, J.Q.; Mahajan, S.M.

    1996-05-01

    A kinetic model for electrons in dusty plasmas is developed. The Boltzmann and the dust charging balance equations are solved self-consistently. The dependence of the dust particle surface potential on plasma parameters and the effects of particulate contamination on electron energy distribution are investigated for direct-current argon glow discharges. It is shown that the dust particle surface potential obtained from this model is higher than that obtained for a Maxwellian electron distribution, and that the higher energy portion of the electron distribution is reduced in the presence of dust particles. Electron-dust collection and electron-atom inelastic collision are the main electron energy loss processes, and the electron energy loss due to electron-dust elastic collision is negligibly small for 10 -16 V cm 2 -15 V cm 2 under the discharge conditions considered in this work, where E is the externally applied electric field and N is the argon atom density. (author). 16 refs, 8 figs

  1. Nonlocal electron kinetics and spectral line emission in the positive column of an argon glow discharge

    International Nuclear Information System (INIS)

    Golubovskii, Yu; Kalanov, D; Gorchakov, S; Uhrlandt, D

    2015-01-01

    Modern non-local electron kinetics theory predicts several interesting effects connected with spectral line emission from the positive column in the range of low and medium pressures and currents. Some theoretical works describe non-monotonic behavior of the radial profiles of line emission at intermediate pressures and currents between the validity ranges of the non-local and local approximation of the electron kinetics. Despite a great number of publications, there have been no systematic measurements attempting to confirm these theoretical predictions through experiments. In this work the radial profiles of the line emission from the positive column of an argon glow discharge have been measured with high spatial resolution and new effects caused by the narrowing and broadening of the spatial emission profiles with dependence on discharge conditions have been discovered. The effect of intensity maximum shift predicted by theory using a self-consistent model was not found in the experiment. The properties of the spectral line radiation are influenced by the peculiarities of the formation of the high-energy tail of the electron energy distribution function. An interpretation of the observed effects based on the non-local character of the electron kinetics in radially inhomogeneous fields is given. The obtained experimental data are compared with the results of calculations. (paper)

  2. Isotopic abundance measurements on solid nuclear-type samples by glow discharge mass spectrometry

    International Nuclear Information System (INIS)

    Betti, M.; Rasmussen, G.; Koch, L.

    1996-01-01

    A double-focusing glow discharge mass spectrometer (GDMS) installed in a glovebox for nuclear sample screening has been employed for isotopic measurements. Isotopic compositions of zirconium, silicon, lithium, boron, uranium and plutonium which are elements of nuclear concern have been determined. Interferences arising from the matrix sample and the discharge gas (Ar) for each of these elements are discussed. The GDMS results are compared with those from thermal ionization mass spectrometry (TIMS). For boron and lithium at μg/g-ng/g levels, the two methods gave results in good agreement. In samples containing uranium the isotopic composition obtained by GDMS was in agreement with those from TIMS independently of the enrichment. Attempts for the determination of plutonium isotopic composition were also made. In this case, due to the interferences of uranium at mass 238 and americium at mass 241, the GDMS raw data are complementary with those values obtained from physical non-destructive techniques. (orig.). With 2 figs., 4 tabs

  3. Performances of helium, neon and argon glow discharges for reduction of fuel hydrogen retention in tungsten, stainless steel and graphite

    International Nuclear Information System (INIS)

    Hino, T.; Yamauchi, Y.; Kimura, Y.; Matsumoto, A.; Nishimura, K.; Ueda, Y.

    2012-11-01

    It is quite important to investigate the performance of glow discharge conditionings for controls of in-vessel tritium (T) inventory and hydrogen recycling. For this purpose, first, the deuterium (D) retentions in tungsten (W), graphite (C) and stainless steel (SS) were measured. The retention in W was not small as expected, several times larger than that of SS, although the retention in SS was one order smaller than that of C. Such the large retention in W is owing to the growth of rough surface structure produced by plasma irradiations. For reduction of deuterium retention in W, SS and C, second, inert gas (He, Ne, Ar) glow discharges were conducted under the same condition, and these performances were compared. The removal ratio of deuterium retention was highest in He discharge, and lowest in Ar discharge. These values are well explained by the numerical analyses using SRIM code. The removal ratios for SS and C were significantly large, but quite small for W. This reason is again owing to the rough surface structure in W. For W, thirdly, the hydrogen isotope exchange and the wall baking experiments were conducted. It is found that the wall backing with a temperature higher than 700 K can well reduce the retention, and the hydrogen isotope exchange using deuterium glow discharge is also useful to reduce the tritium retention in the wall. The present results significantly contribute to control the fuel hydrogen retention and to reduce the in-vessel tritium inventory in fusion reactors. (author)

  4. Aspects of the practical application of titanium alloys after low temperature nitriding glow discharge in hydrogen- free -gas media

    Energy Technology Data Exchange (ETDEWEB)

    Mashovets, N.S., E-mail: mashovets@rambler.ru [Khmelnickiy National University (Ukraine); Pastukh, I.M., E-mail: pastim@mail.ru [Khmelnickiy National University (Ukraine); Voloshko, S.M. [Khmelnickiy National University (Ukraine); National Technical University of Ukraine “Kyiv Polytechnic Institute” (Ukraine)

    2017-01-15

    Highlights: • Surface modification of titanium alloys were carried out by low-temperature nitriding in a glow discharge in hydrogen-free environment. • Research into the phase composition was performed by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). • The above material shows the promise of the technology of low-temperature hydrogen-nitriding by glow discharge. This greatly expands the range of practical applications of titanium alloys. - Abstract: X-ray diffraction analysis, X-ray photoelectron spectroscopy, and Electron Auger-spectroscopy investigation of phase transformation on the surface of the VT8 titanium alloy after a low temperature hydrogen-free nitriding in a glow discharge. Operational characteristics of titanium alloys defined physical-mechanical characteristics of the surface and their phase composition, which depend on the process parameters of nitriding. Surface modification of titanium alloys were carried out by low-temperature nitriding in a glow discharge in hydrogen-free environment. The main advantage of this method lies in the absence of hydrogen embrittlement and complete environmental safety process. Application of the glow discharge can not only speed up the process by the order of the diffusion surface saturation with nitrogen, but also significantly alters the kinetics of the process and quality of the nitrided layer, in particular its physio-mechanical properties and phase composition. For research purposes, the standards from an α + β alloy Ti-Al6-Cr2-Mo2,5 (VT8) were used. Research into the phase composition was performed by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Stratified analysis by AES was conducted by etching the surface of the samples’ argon ion beam with diameters of 1.5 mm with an energy of 3000 eV and a current density of 400 mA/cm{sup 2}. The above material shows the promise of the technology of low

  5. Aspects of the practical application of titanium alloys after low temperature nitriding glow discharge in hydrogen- free -gas media

    International Nuclear Information System (INIS)

    Mashovets, N.S.; Pastukh, I.M.; Voloshko, S.M.

    2017-01-01

    Highlights: • Surface modification of titanium alloys were carried out by low-temperature nitriding in a glow discharge in hydrogen-free environment. • Research into the phase composition was performed by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). • The above material shows the promise of the technology of low-temperature hydrogen-nitriding by glow discharge. This greatly expands the range of practical applications of titanium alloys. - Abstract: X-ray diffraction analysis, X-ray photoelectron spectroscopy, and Electron Auger-spectroscopy investigation of phase transformation on the surface of the VT8 titanium alloy after a low temperature hydrogen-free nitriding in a glow discharge. Operational characteristics of titanium alloys defined physical-mechanical characteristics of the surface and their phase composition, which depend on the process parameters of nitriding. Surface modification of titanium alloys were carried out by low-temperature nitriding in a glow discharge in hydrogen-free environment. The main advantage of this method lies in the absence of hydrogen embrittlement and complete environmental safety process. Application of the glow discharge can not only speed up the process by the order of the diffusion surface saturation with nitrogen, but also significantly alters the kinetics of the process and quality of the nitrided layer, in particular its physio-mechanical properties and phase composition. For research purposes, the standards from an α + β alloy Ti-Al6-Cr2-Mo2,5 (VT8) were used. Research into the phase composition was performed by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Stratified analysis by AES was conducted by etching the surface of the samples’ argon ion beam with diameters of 1.5 mm with an energy of 3000 eV and a current density of 400 mA/cm 2 . The above material shows the promise of the technology of low

  6. Emission characteristics of 6.78-MHz radio-frequency glow discharge plasma in a pulsed mode

    Science.gov (United States)

    Zhang, Xinyue; Wagatsuma, Kazuaki

    2017-07-01

    This paper investigated Boltzmann plots for both atomic and ionic emission lines of iron in an argon glow discharge plasma driven by 6.78-MHz radio-frequency (RF) voltage in a pulsed operation, in order to discuss how the excitation/ionization process was affected by the pulsation. For this purpose, a pulse frequency as well as a duty ratio of the pulsed RF voltage was selected as the experimenter parameters. A Grimm-style radiation source was employed at a forward RF power of 70 W and at an argon pressures of 670 Pa. The Boltzmann plot for low-lying excited levels of iron atom was on a linear relationship, which was probably attributed to thermal collisions with ultimate electrons in the negative glow region; in this case, the excitation temperature was obtained in a narrow range of 3300-3400 K, which was hardly affected by the duty ratio as well as the pulse frequency of the pulsed RF glow discharge plasma. This observation suggested that the RF plasma could be supported by a self-stabilized negative glow region, where the kinetic energy distribution of the electrons would be changed to a lesser extent. Additional non-thermal excitation processes, such as a Penning-type collision and a charge-transfer collision, led to deviations (overpopulation) of particular energy levels of iron atom or iron ion from the normal Boltzmann distribution. However, their contributions to the overall excitation/ionization were not altered so greatly, when the pulse frequency or the duty ratio was varied in the pulsed RF glow discharge plasma.

  7. Influence of thin porous Al2O3 layer on aluminum cathode to the Hα line shape in glow discharge

    International Nuclear Information System (INIS)

    Steflekova, V.; Sisovic, N. M.; Konjevic, N.

    2009-01-01

    The results of the Balmer alfa line shape study in a plane cathode-hollow anode Grimm discharge with aluminum (Al) cathode covered with thin layer of porous Al 2 O 3 are presented. The comparison with same line profile recorded with pure Al cathode shows lack of excessive Doppler broadened line wings, which are always detected in glow discharge with metal cathode. The effect is explained by the lack of strong electric field in the cathode sheath region, which is missing in the presence of thin oxide layer in, so called, spray discharge.

  8. Analysing bifurcations encountered in numerical modelling of current transfer to cathodes of dc glow and arc discharges

    International Nuclear Information System (INIS)

    Almeida, P G C; Benilov, M S; Cunha, M D; Faria, M J

    2009-01-01

    Bifurcations and/or their consequences are frequently encountered in numerical modelling of current transfer to cathodes of gas discharges, also in apparently simple situations, and a failure to recognize and properly analyse a bifurcation may create difficulties in the modelling and hinder the understanding of numerical results and the underlying physics. This work is concerned with analysis of bifurcations that have been encountered in the modelling of steady-state current transfer to cathodes of glow and arc discharges. All basic types of steady-state bifurcations (fold, transcritical, pitchfork) have been identified and analysed. The analysis provides explanations to many results obtained in numerical modelling. In particular, it is shown that dramatic changes in patterns of current transfer to cathodes of both glow and arc discharges, described by numerical modelling, occur through perturbed transcritical bifurcations of first- and second-order contact. The analysis elucidates the reason why the mode of glow discharge associated with the falling section of the current-voltage characteristic in the solution of von Engel and Steenbeck seems not to appear in 2D numerical modelling and the subnormal and normal modes appear instead. A similar effect has been identified in numerical modelling of arc cathodes and explained.

  9. Filling the vacuum chamber of a technological system with homogeneous plasma using a stationary glow discharge

    International Nuclear Information System (INIS)

    Metel, A. S.; Grigoriev, S. N.; Melnik, Yu. A.; Panin, V. V.

    2009-01-01

    Experimental study of a glow discharge with electrostatic confinement of electrons is carried out in the vacuum chamber volume V ∼ 0.12 m 3 of a technological system 'Bulat-6' in argon pressure range 0.005-5 Pa. The chamber is used as a hollow cathode of the discharge with the inner surface area S ∼ 1.5 m 2 . It is equipped with two feedthroughs, which make it possible to immerse in the discharge plasma interchangeable anodes with surface area S a ranging from ∼0.001 to ∼0.1 m 2 , as well as floating electrodes isolated from both the chamber and the anode. Dependences of the cathode fall U c = 0.4-3 kV on the pressure p at a constant discharge current in the range I = 0.2-2 A proved that aperture of the electron escape out of the electrostatic trap is equal to the sum S o = S a + S f of the anode surface S a and the floating electrode surface S f . The sum S o defines the lower limit p o of the pressure range, in which U c is independent of p. At p o the cathode fall U c grows up dramatically, when the pressure decreases, and the pressure p tends to the limit p ex , which is in fact the discharge extinction pressure. At p ∼ p ex electrons emitted by the cathode and the first generation of fast electrons produced in the cathode sheath spend almost all their energy up to 3 keV on heating the anode and the floating electrode up to 600-800 o C and higher. In this case the gas in the chamber is being ionized by the next generations of electrons produced in the cathode sheath, their energy being one order of magnitude lower. When S a 1/2 S, where m is the electron mass and M is the ion mass, the anode may be additionally heated by plasma electrons accelerated by the anode fall of potential U a up to 0.5 kV.

  10. Enhancing DC Glow Discharge Tube Museuum Displays using a Theremin Controlled Helmholtz Coil to Demonstrate Magnetic Confinement

    Science.gov (United States)

    Siu, Theodore; Wissel, Stephanie; Guttadora, Larry; Liao, Susan; Zwicker, Andrew

    2010-11-01

    Since their discovery in the mid 1800's, DC glow discharge apparatuses have commonly been used for spectral analysis, the demonstration of the Frank-Hertz experiment, and to study plasma breakdown voltages following from the Paschen Curve. A DC glow discharge tube museum display was outfitted with a Helmholtz Coil electromagnet in order to demonstrate magnetic confinement for a science museum display. A device commonly known as a ``theremin'' was designed and built in order to externally control the Helmholtz Coil current and the plasma current. Originally a musical instrument, a theremin has two variable capacitors connected to two radio frequency oscillators which determine pitch and volume. Using a theremin to control current and ``play'' the plasma adds appeal and durability by providing a new innovative means of interacting with a museum exhibit. Educationally, students can use the display to not only learn about plasma properties but also electronic properties of the human body.

  11. Destruction of 4-phenolsulfonic acid in water by anodic contact glow discharge electrolysis.

    Science.gov (United States)

    Yang, Haiming; An, Baigang; Wang, Shaoyan; Li, Lixiang; Jin, Wenjie; Li, Lihua

    2013-06-01

    Destruction of 4-phenolsulfonic acid (4-PSA) in water was carried out using anodic contact glow discharge electrolysis. Accompanying the decay of 4-PSA, the amount of total organic carbon (TOC) in water correspondingly decreased, while the sulfonate group of 4-PSA was released as sulfate ion. Oxalate and formate were obtained as minor by-products. Additionally, phenol, 1,4-hydroquinone, hydroxyquinol and 1,4-benzoquinone were detected as primary intermediates in the initial stages of decomposition of 4-PSA. A reaction pathway involving successive attacks of hydroxyl and hydrogen radicals was assumed on the basis of the observed products and kinetics. It was revealed that the decay of both 4-PSA and TOC obeyed a first-order rate law. The effects of different Fe ions and initial concentrations of 4-PSA on the degradation rate were investigated. It was found that the presence of Fe ions could increase the degradation rate of 4-PSA, while initial concentrations lower than 80 mmol/L had no significant effect on kinetic behaviour. The disappearance rate of 4-PSA was significantly affected by pH.

  12. On copper diffusion in silicon measured by glow discharge mass spectrometry.

    Science.gov (United States)

    Modanese, Chiara; Gaspar, Guilherme; Arnberg, Lars; Di Sabatino, Marisa

    2014-11-01

    Copper contamination occurs frequently in silicon for photovoltaic applications due to its very fast diffusion coupled with a low solid solubility, especially at room temperature. The combination of these properties exerts a challenge on the direct analysis of Cu bulk concentration in Si by sputtering techniques like glow discharge mass spectrometry (GDMS). This work aims at addressing the challenges in quantitative analysis of fast diffusing elements in Si matrix by GDMS. N-type, monocrystalline (Czochralski) silicon samples were intentionally contaminated with Cu after solidification and consequently annealed at 900 °C to ensure a homogeneous distribution of Cu in the bulk. The samples were quenched after annealing to control the extent of the diffusion to the surface prior to the GDMS analyses, which were carried out at different time intervals from within few minutes after cooling onward. The Cu profiles were measured by high-resolution GDMS operating in a continuous direct current mode, where the integration step length was set to ∼0.5 μm over a total sputtered depth of 8-30 μm. The temperature of the samples during the GDMS analyses was also measured in order to evaluate the diffusion. The Cu contamination of n-type Si samples was observed to be highly material dependent. The practical impact of Cu out-diffusion on the calculation of the relative sensitivity factor (RSF) of Cu in Si is discussed.

  13. Product surface hardening in non-self-sustained glow discharge plasma before synthesis of superhard coatings

    International Nuclear Information System (INIS)

    Krasnov, P S; Metel, A S; Nay, H A

    2017-01-01

    Before the synthesis of superhard coating, the product surface is hardened by means of plasma nitriding, which prevents the surface deformations and the coating brittle rupture. The product heating by ions accelerated from plasma by applied to the product bias voltage leads to overheating and blunting of the product sharp edges. To prevent the blunting, it is proposed to heat the products with a broad beam of fast nitrogen molecules. The beam injection into a working vacuum chamber results in filling of the chamber with quite homogeneous plasma suitable for nitriding. Immersion in the plasma of the electrode and heightening of its potential up to 50–100 V initiate a non-self-sustained glow discharge between the electrode and the chamber. It enhances the plasma density by an order of magnitude and reduces its spatial nonuniformity down to 5–10%. When a cutting tool is isolated from the chamber, it is bombarded by plasma ions with an energy corresponding to its floating potential, which is lower than the sputtering threshold. Hence, the sharp edges are sputtered only by fast nitrogen molecules with the same rate as other parts of the tool surface. This leads to sharpening of the cutting tools instead of blunting. (paper)

  14. Submerged Glow-Discharge Plasma: An Economical Approach to Convert Construction Scrap Metal into Nanomaterials

    Directory of Open Access Journals (Sweden)

    Yek Peter Nai Yuh

    2018-01-01

    Full Text Available Submerged glow-discharge plasma (SGDP is relatively new among the various methods available for nanomaterials synthesis (NMs techniques. This method allows great control over the production cost of nanomaterials synthesis. A lab-scale batch type SDGP technology has been constructed to produce nanomaterials and investigate the inter-relationship between plasma excitation voltages, electrodes submerged areas and electrolyte concentration. Metal oxide nanospheres has been synthesised from different electrolyte concentrations (1M-0.001M and characterized by Scanning Electron Microscopy (SEM and Energy Dispersive Spectroscopy (EDS. As the major results showed that the nanospheres are uniformly spherical with diameter size distribution are between 100 nm - 2μm. EDS analysis shown the nano-Iron Oxide have been formed. Scrap metal initially showed around 6.45% and 93.55% of Carbon and Iron composition respectively. After SGDP process to the scrap metal, Carbon content has increased to 34-35% and Iron content has reduced to around 15-40%. EDS results also shown the higher percentage of Iron amount has remained with lower electrolyte concentration and Current is proportionally related to submersion area of cathode.

  15. Contact glow discharge electrolysis: its origin, plasma diagnostics and non-faradaic chemical effects

    International Nuclear Information System (INIS)

    Sen Gupta, Susanta K

    2015-01-01

    Contact glow discharge electrolysis (CGDE) also termed plasma electrolysis is a novel electrolysis where a stable sheath of light emitting plasma develops around an electrode immersed well inside a relatively high-conductivity liquid electrolyte during normal electrolysis (NE) at several hundred volts. The phenomenon may develop in dc-, pulsed dc-, ac- as well as RF-driven electrolyses. The chemical effects of CGDE are remarkably non-faradaic in respect to the nature of the products as well as their yields. The article traces comprehensively the progress made in studies of CGDE in aqueous and non-aqueous solutions since 1844 and reviews the developments in the understanding of its origin, light emission, plasma state and non-faradaic effects leading to the elucidation of detailed mechanism of the origin of CGDE on the basis of the onset of hydrodynamic instabilities in local vaporization of the solvent near the working electrode during NE, and that of highly non-faradaic effects of CGDE based on a model of two reaction zones located within the electrode plasma and at the plasma–liquid interface producing solvent derived radicals at high local concentrations. Keeping in view the recent surge of interest in varied applications of CGDE, the article is appended with highlights of these applications across synthetic chemistry, waste water treatment, electrosurgical devices, nanoparticle fabrications, surface engineering and micro-machining. (topical review)

  16. Dechlorination and decomposition of chloroform induced by glow discharge plasma in an aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yongjun, E-mail: lyjglow@sohu.com [College of Environmental Science & Engineering, Dalian Maritime University, Dalian 116026 (China); Brook Byers Institute for Sustainable Systems, Georgia Institute of Technology, Atlanta 30332 (United States); Crittenden, John C. [Brook Byers Institute for Sustainable Systems, Georgia Institute of Technology, Atlanta 30332 (United States); Wang, Lei [College of Environmental Science & Engineering, Xiamen University of Technology, Xiamen 361024 (China); Liu, Panliang [Brook Byers Institute for Sustainable Systems, Georgia Institute of Technology, Atlanta 30332 (United States)

    2016-05-05

    Highlights: • Hydrated electrons played an important role for chloroform decomposition. • Oxygen enhanced hydrolyses are critical for the chloroform mineralization. • Energy efficiency of GDP is higher than those of the typical competitive processes. - Abstract: In this study, efficient dechlorination and decomposition of chloroform (CF) induced by glow discharge plasma (GDP) in contact with a sodium sulfate solution was investigated. Intermediate byproducts were determined by ionic chromatography and headspace gas chromatography, respectively. Results showed that CF can be effectively dechlorinated and decomposed under the action of GDP. Both removal and dechlorination of CF increased with increasing pH and with addition of hydroxyl radical scavengers to the solution. Addition of H{sub 2}O{sub 2} to the solution slightly decreased the CF removal. Formic acid, oxalic acid and dichloromethane were determined as the major intermediate byproducts. Final products were carbon dioxide and hydrochloric acid. Hydrated electrons were the most likely active species responsible for initiation of the dechlorination, and hydroxyl radicals may be the ones for the oxidation of the organic intermediate byproducts. Hydrolyses of the chloromethyl radicals contributed much in the mineralization of the organic chlorine. Reaction mechanism was proposed based on the dechlorination kinetics and the distribution of intermediate byproducts.

  17. Surface Modification of Asymmetric Polysulfone/Polyethylene Glycol Membranes by DC Ar-Glow Discharge Plasma

    Directory of Open Access Journals (Sweden)

    Chalad Yuenyao

    2016-01-01

    Full Text Available Polysulfone/polyethylene glycol (PSF/PEG membranes were prepared by dry/wet phase inversion method. Effects of direct current glow discharge plasma using argon as working gas on morphological structures and gas separation properties of membranes were studied. Alteration of membrane characteristics were analyzed by various techniques like contact angle, scanning electron microscope, Fourier transform infrared spectroscopy, and dynamic mechanical thermal analysis. Gas separation properties were measured in terms of permeation and ideal O2/N2 selectivity. Results showed that hydrophilic and gas separation properties of PSF/PEG membranes increased by plasma surface modification. It was also shown that the dosage of PEG and plasma treatment affected the morphological structures and mechanical and gas separation properties. The macro voids and transmembrane structure disappeared with a little amount of PEG dosage. Pore size and mechanical strength tend to decrease with increasing PEG dosage up to 10 wt%. Glass transition temperature (Tg receded from 201.8 to 143.7°C for pure PSF and PSF/PEG with PEG dosage of 10 wt%. O2 and N2 gases permeation through the 10-minute plasma treated membranes tend to increase. However, the permeation strongly dispersed when treatment time was more extended.

  18. Cell treatment and surface functionalization using a miniature atmospheric pressure glow discharge plasma torch

    International Nuclear Information System (INIS)

    Yonson, S; Coulombe, S; Leveille, V; Leask, R L

    2006-01-01

    A miniature atmospheric pressure glow discharge plasma torch was used to detach cells from a polystyrene Petri dish. The detached cells were successfully transplanted to a second dish and a proliferation assay showed the transplanted cells continued to grow. Propidium iodide diffused into the cells, suggesting that the cell membrane had been permeabilized, yet the cells remained viable 24 h after treatment. In separate experiments, hydrophobic, bacteriological grade polystyrene Petri dishes were functionalized. The plasma treatment reduced the contact angle from 93 0 to 35 0 , and promoted cell adhesion. Two different torch nozzles, 500 μm and 150 μm in internal diameter, were used in the surface functionalization experiments. The width of the tracks functionalized by the torch, as visualized by cell adhesion, was approximately twice the inside diameter of the nozzle. These results indicate that the miniature plasma torch could be used in biological micropatterning, as it does not use chemicals like the present photolithographic techniques. Due to its small size and manouvrability, the torch also has the ability to pattern complex 3D surfaces

  19. Chemical corrosion by chlorides on ancient-like bronzes and treatment by hydrogen glow discharge plasma

    Science.gov (United States)

    Papadopoulou, O.; Novakovic, J.; Vassiliou, P.; Filippaki, E.; Bassiakos, Y.

    2013-12-01

    Three representative ancient-like bronzes are employed for the chemical synthesis of Cu2(OH)3Cl rich patinas in order to study the influence of the alloying elements in the evolution of the chloride attack and to further conduct stabilization treatment via Hydrogen Glow Discharge Plasma (HGDP) at low temperature and pressure. The corrosion behavior of specimens having Sn and Pb as main alloying elements is governed by a decuprification mechanism and by the formation of Sn-Pb-O enriched barrier layers. In the case of the Zn containing alloy, dezincification is more pronounced at the corrosion initial stages, and copper species predominate the corrosion products evolution. A three-hour HGDP treatment leads to Cu+ production and metallic Cu, Sn, Zn, and Pb redeposition, as a result of metal cation reduction. This process is accompanied by partial removal of Cl species, O diminution, and change in coloration. The further increase of the Cl/O atomic ratio measured on the post-treated surfaces leads to the formation of nantokite and thus to the conclusion that the stabilization of objects with extensive Cl attack is not feasible by HGDP without preliminary chemical treatment.

  20. Pulsed laser ablation of borax target in vacuum and hydrogen DC glow discharges

    Science.gov (United States)

    Kale, A. N.; Miotello, A.; Mosaner, P.

    2006-09-01

    The aim of our experiment was to produce a material with B sbnd H bonds for applications in hydrogen storage and generation. By using KrF excimer laser ( λ = 248 nm) ablation of borax (Na 2B 4O 7) target, thin films were deposited on KBr and silicon substrates. Ablation was performed both in vacuum and in hydrogen atmosphere. DC glow discharge technique was utilized to enhance hydrogen gas ionization. Experiments were performed using laser fluence from 5 to 20 J/cm 2. Films were deposited under gas pressure of 1 × 10 -5 to 5 × 10 -2 mbar and substrate temperatures of 130-450 °C. Scanning electron microscopy analysis of films showed presence of circular particulates. Film thickness, roughness and particulates number increased with increase in laser fluence. Energy dispersive X-ray spectroscopy analysis shows that sodium content in the particulates is higher than in the target. This effect is discussed in terms of atomic arrangements (both at surface and bulk) in systems where ionic and covalent bonds are present and by looking at the increased surface/bulk ratio of the particulates with respect to the deposited films. The Fourier transform infrared spectroscopy measurements showed presence of B sbnd O stretching and B sbnd O sbnd B bending bonds. Possible reasons for absence of B sbnd H bonds are attributed to binding enthalpy of the competing molecules.

  1. Calorimetry of energy-efficient glow discharge apparatus design and calibration

    International Nuclear Information System (INIS)

    Benson, Thomas B.; Passell, Thomas O.

    2006-01-01

    This work aims to develop a 'family' or low-powered calorimetrically accurate glow discharge units, similar to that reported by Dardik et al. at lCCF-10, and to use these to test a wide range or cathode materials, electrode coatings, gas types, gas pressures, and power input levels. We will describe the design and calibration of these units. The strategy is to use a large number of very similar units so that the calorimetric response does not vary significantly for a given power level. The design is metal or sealed glass cylindrical tubes, charged with 0.4 - 50 Torr mixtures of deuterium, hydrogen, argon, or helium gases. Units operate from 0.2 to >2 W power input. The units have low mass ( 1.2 with more than 95% certainty. It provides a valuable new platform for large-scale exploration of excess heat effects in the gas phase, using low-power inputs in the 0-3 W range, This method proves to be inexpensive, quick, accurate, and easy to perform once the basics are mastered. The authors are interested in testing electrode materials from other sources, especially those that have already been successful in a liquid (electrolytic) environment

  2. Application of Glow Discharge Plasma to Alter Surface Properties of Materials

    Science.gov (United States)

    Trigwell, Steve; Buhler, Charles R.; Calle, Carlos I.

    2005-01-01

    Some polymer materials that are considered important for spaceport operations are rendered noncompliant when subjected to the Kennedy Space Center (KSC) Standard electrostatic testing. These materials operate in stringent environmental conditions, such as high humidity. Treating materials that fail electrostatic testing and altering their surface properties so that they become compliant would result in considerable cost savings. Significant improvement in electrostatic dissipation of Saf-T-Vu PVC after treatment with air Atmospheric Plasma Glow Discharge (APGD) was observed and the material now passed the KSC electrostatic test. The O:C ratio on the surface, as monitored by X-ray Photoelectron Spectroscopy, increased from 0.165 tO 0.275 indicating enhanced oxidation, and surface contact angle measurements decreased from 107.5 to 72.6 showing increased hydrophilicity that accounted for the increased conductivity. Monitoring of the aging showed that the materials hydrophobic recovery resulted in it failing the electrostatic test 30 hours after treatment. This was probably due to the out-diffusion of the added Zn, Ba, and Cd salt stabilizers detected on the surface and/or diffusion of low molecular weight oligomers. On going work includes improving the long term hydrophilicity by optimizing the APGD process with different gas mixtures. Treatment of other spaceport materials is also presented.

  3. Submerged Glow-Discharge Plasma: An Economical Approach to Convert Construction Scrap Metal into Nanomaterials

    Science.gov (United States)

    Yek, Peter Nai Yuh; Rafiq Mirza Julaihi, Muhammad; Shahril Osman, Mohammad; Tiong, Tung Chuan; Lee, Wak Ha; Leing Lee, Chern

    2018-03-01

    Submerged glow-discharge plasma (SGDP) is relatively new among the various methods available for nanomaterials synthesis (NMs) techniques. This method allows great control over the production cost of nanomaterials synthesis. A lab-scale batch type SDGP technology has been constructed to produce nanomaterials and investigate the inter-relationship between plasma excitation voltages, electrodes submerged areas and electrolyte concentration. Metal oxide nanospheres has been synthesised from different electrolyte concentrations (1M-0.001M) and characterized by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). As the major results showed that the nanospheres are uniformly spherical with diameter size distribution are between 100 nm - 2μm. EDS analysis shown the nano-Iron Oxide have been formed. Scrap metal initially showed around 6.45% and 93.55% of Carbon and Iron composition respectively. After SGDP process to the scrap metal, Carbon content has increased to 34-35% and Iron content has reduced to around 15-40%. EDS results also shown the higher percentage of Iron amount has remained with lower electrolyte concentration and Current is proportionally related to submersion area of cathode.

  4. Dechlorination and decomposition of chloroform induced by glow discharge plasma in an aqueous solution

    International Nuclear Information System (INIS)

    Liu, Yongjun; Crittenden, John C.; Wang, Lei; Liu, Panliang

    2016-01-01

    Highlights: • Hydrated electrons played an important role for chloroform decomposition. • Oxygen enhanced hydrolyses are critical for the chloroform mineralization. • Energy efficiency of GDP is higher than those of the typical competitive processes. - Abstract: In this study, efficient dechlorination and decomposition of chloroform (CF) induced by glow discharge plasma (GDP) in contact with a sodium sulfate solution was investigated. Intermediate byproducts were determined by ionic chromatography and headspace gas chromatography, respectively. Results showed that CF can be effectively dechlorinated and decomposed under the action of GDP. Both removal and dechlorination of CF increased with increasing pH and with addition of hydroxyl radical scavengers to the solution. Addition of H_2O_2 to the solution slightly decreased the CF removal. Formic acid, oxalic acid and dichloromethane were determined as the major intermediate byproducts. Final products were carbon dioxide and hydrochloric acid. Hydrated electrons were the most likely active species responsible for initiation of the dechlorination, and hydroxyl radicals may be the ones for the oxidation of the organic intermediate byproducts. Hydrolyses of the chloromethyl radicals contributed much in the mineralization of the organic chlorine. Reaction mechanism was proposed based on the dechlorination kinetics and the distribution of intermediate byproducts.

  5. A novel synthesis method for large area metallic amorphous/nanocrystal films by the glow-discharge plasma technique

    International Nuclear Information System (INIS)

    Xu Jiang; Xu Zhong; Tao Jie; Liu Zili; Chen Zheyuan; Zhu Wenhui

    2007-01-01

    Two large-area metallic amorphous/nanocrystal films were prepared on AZ31 magnesium alloy and pure iron substrates by the double glow-discharge plasma technique. The formation mechanism of the novel amorphous films did not follow the established empirical rules for large glass-forming ability. The amorphous films were composed of binary alloys with a difference in the atomic diameter of alloying constituents of less than 12%, and an amorphous film of pure iron was successfully obtained

  6. A rate-equation model for polarized laser-induced fluorescence to measure electric field in glow discharge He plasmas

    International Nuclear Information System (INIS)

    Takiyama, K.; Watanabe, M.; Oda, T.

    1998-01-01

    Possibility of applying polarized laser-induced fluorescence (LIF) spectroscopy for measuring the electric field in a plasma with a large collisional depolarization has been investigated. A rate equation model including the depolarization process was employed to analyze the time evolution of LIF polarization components. The polarized LIF pulse shapes observed in the sheath of a He glow discharge plasma were successfully reproduced, and the electric field distribution was obtained with high accuracy. (author)

  7. Comparison in the analytical performance between krypton and argon glow discharge plasmas as the excitation source for atomic emission spectrometry.

    Science.gov (United States)

    Wagatsuma, Kazuaki

    2009-04-01

    The emission characteristics of ionic lines of nickel, cobalt, and vanadium were investigated when argon or krypton was employed as the plasma gas in glow discharge optical emission spectrometry. A dc Grimm-style lamp was employed as the excitation source. Detection limits of the ionic lines in each iron-matrix alloy sample were compared between the krypton and the argon plasmas. Particular intense ionic lines were observed in the emission spectra as a function of the discharge gas (krypton or argon), such as the Co II 258.033 nm for krypton and the Co II 231.707 nm for argon. The explanation for this is that collisions with the plasma gases dominantly populate particular excited levels of cobalt ion, which can receive the internal energy from each gas ion selectively, for example, the 3d(7)4p (3)G(5) (6.0201 eV) for krypton and the 3d(7)4p (3)G(4) (8.0779 eV) for argon. In the determination of nickel as well as cobalt in iron-matrix samples, more sensitive ionic lines could be found in the krypton plasma rather than the argon plasma. Detection limits in the krypton plasma were 0.0039 mass% Ni for the Ni II 230.299-nm line and 0.002 mass% Co for the Co II 258.033-nm line. However, in the determination of vanadium, the argon plasma had better analytical performance, giving a detection limit of 0.0023 mass% V for the V II 309.310-nm line.

  8. Conditioning of SST-1 Tokamak Vacuum Vessel by Baking and Glow Discharge Cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Ziauddin, E-mail: ziauddin@ipr.res.in; George, Siju; Semwal, Pratibha; Dhanani, Kalpeshkumar R.; Pathan, Firozkhan S.; Paravastu, Yuvakiran; Raval, Dilip C.; Babu, Gattu Ramesh; Khan, Mohammed Shoaib; Pradhan, Subrata

    2016-02-15

    Highlights: • SST-1 Tokamak was successfully commissioned. • Vacuum vessel was pumped down to 4.5 × 10{sup –8} mbar after baking and continuous GDC. • GDC reduced the water vapour by additional 57% while oxygen was reduced by 50%. • Under this condition, an initial plasma breakdown with current of 40 kA for 75 ms was achieved. - Abstract: Steady-state Superconducting Tokamak (SST-1) vacuum vessel (VV) adopts moderate baking at 110 ± 10 °C and the limiters baking at 250 ± 10 °C for ∼ 200 h followed by glow discharge cleaning in hydrogen (GDC-H) with 0.15 A/m{sup 2} current density towards its conditioning prior to plasma discharge experiment. The baking in SST-1 reduces the water (H{sub 2}O) vapor by 95% and oxygen (O{sub 2}) by 60% whereas the GDC reduces the water vapor by an additional 57% and oxygen by another 50% as measured with residual gas analyzer. The minimum breakdown voltage for H-GDC in SST-1 tokamak was experimentally observed to 300 V at 8 mbar cm. As a result of these adherences, SST-1 VV achieves an ultimate of 4.5 × 10{sup −8} mbar with two turbo-molecular pumps with effective pumping speed of 3250 l/s. In the last campaign, SST-1 has achieved successful plasma breakdown, impurity burn through and a plasma current of ∼ 40 kA for 75 ms.

  9. An ion source for radiofrequency-pulsed glow discharge time-of-flight mass spectrometry

    International Nuclear Information System (INIS)

    González Gago, C.; Lobo, L.; Pisonero, J.; Bordel, N.; Pereiro, R.; Sanz-Medel, A.

    2012-01-01

    A Grimm-type glow discharge (GD) has been designed and constructed as an ion source for pulsed radiofrequency GD spectrometry when coupled to an orthogonal time of flight mass spectrometer. Pulse shapes of argon species and analytes were studied as a function of the discharge conditions using a new in-house ion source (UNIOVI GD) and results have been compared with a previous design (PROTOTYPE GD). Different behavior and shapes of the pulse profiles have been observed for the two sources evaluated, particularly for the plasma gas ionic species detected. In the more analytically relevant region (afterglow), signals for 40 Ar + with this new design were negligible, while maximum intensity was reached earlier in time for 41 (ArH) + than when using the PROTOTYPE GD. Moreover, while maximum 40 Ar + signals measured along the pulse period were similar in both sources, 41 (ArH) + and 80 (Ar 2 ) + signals tend to be noticeable higher using the PROTOTYPE chamber. The UNIOVI GD design was shown to be adequate for sensitive direct analysis of solid samples, offering linear calibration graphs and good crater shapes. Limits of detection (LODs) are in the same order of magnitude for both sources, although the UNIOVI source provides slightly better LODs for those analytes with masses slightly higher than 41 (ArH) + . - Highlights: ► A new RF-pulsed GD ion source (UNIOVI GD) coupled to TOFMS has been characterized. ► Linear calibration graphs and LODs in the low ppm range are achieved. ► Craters with flat bottoms and vertical walls are obtained. ► UNIOVI source can be easily cleaned as it does not require flow tube. ► UNIOVI GD has a simple design and thus its manufacture is easy and cheap.

  10. Effects of easily ionizable elements on the liquid sampling-atmospheric pressure glow discharge

    International Nuclear Information System (INIS)

    Venzie, Jacob L.; Marcus, R. Kenneth

    2006-01-01

    A series of studies has been undertaken to determine the susceptibility of the liquid sampling-atmospheric pressure glow discharge (LS-APGD) atomic emission source to easily ionizable element (EIE) effects. The initial portions of the study involved monitoring the voltage drop across the plasma as a function of the pH to ascertain whether or not the conductivity of the liquid eluent alters the plasma energetics and subsequently the analyte signal strength. It was found that altering the pH (0.0 to 2.0) in the sample matrix did not significantly change the discharge voltage. The emission signal intensities for Cu(I) 327.4 nm, Mo(I) 344.7 nm, Sc(I) 326.9 nm and Hg(I) 253.6 nm were measured as a function of the easily ionizable element (sodium and calcium) concentration in the injection matrix. A range of 0.0 to 0.1% (w/v) EIE in the sample matrix did not cause a significant change in the Cu, Sc, and Mo signal-to-background ratios, with only a slight change noted for Hg. In addition to this test of analyte response, the plasma energetics as a function of EIE concentration are assessed using the ratio of Mg(II) to Mg(I) (280.2 nm and 285.2 nm, respectively) intensities. The Mg(II)/Mg(I) ratio showed that the plasma energetics did not change significantly over the same range of EIE addition. These results are best explained by the electrolytic nature of the eluent acting as an ionic (and perhaps spectrochemical) buffer

  11. In-situ characterisation of the dynamics of a growing dust particle cloud in a direct-current argon glow discharge

    International Nuclear Information System (INIS)

    Barbosa, S; Onofri, F R A; Couëdel, L; Arnas, C; Kumar, K Kishor; Pardanaud, C

    2016-01-01

    The growth and the dynamics of a tungsten nanoparticle cloud were investigated in a direct-current low pressure argon glow discharge. Real-time analyses of the dust particle size and number concentration were performed in-situ by light extinction spectrometry, while spatial dynamics of the cloud was investigated with the laser light-sheet scattering method. Additional off-line electron microscopy and Raman spectroscopy measurements were also performed for comparison purpose. This experimental work reveals the existence of an agglomeration phase followed by the appearance of a new dust particle generation. While growing, the dust cloud is pushed towards the anode and the discharge edge. Afterwards, a new dust particle generation can grow in the space freed by the first generation of nanoparticles. The continuous growth, below the light extinction spectrometry scanning positions, explains the apparent dissimilarities observed between the in-line optical and the off-line electron microscopy analyses. (paper)

  12. Investigation of Gas Heating by Nanosecond Repetitively Pulsed Glow Discharges Used for Actuation of a Laminar Methane-Air Flame

    KAUST Repository

    Lacoste, Deanna

    2017-05-24

    This paper reports on the quantification of the heating induced by nanosecond repetitively pulsed (NRP) glow discharges on a lean premixed methane-air flame. The flame, obtained at room temperature and atmospheric pressure, has an M-shape morphology. The equivalence ratio is 0.95 and the thermal power released by the flame is 113 W. The NRP glow discharges are produced by high voltage pulses of 10 ns duration, 7 kV amplitude, applied at a repetition frequency of 10 kHz. The average power of the plasma, determined from current and voltage measurements, is 1 W, i.e. about 0.9 % of the thermal power of the flame. Broadband vibrational coherent anti-Stokes Raman spectroscopy of nitrogen is used to determine the temperature of the flame with and without plasma enhancement. The temperature evolution in the flame area shows that the thermal impact of NRP glow discharges is in the uncertainty range of the technique, i.e., +/- 40 K.

  13. Transport Equations Resolution By N-BEE Anti-Dissipative Scheme In 2D Model Of Low Pressure Glow Discharge

    International Nuclear Information System (INIS)

    Kraloua, B.; Hennad, A.

    2008-01-01

    The aim of this paper is to determine electric and physical properties by 2D modelling of glow discharge low pressure in continuous regime maintained by term constant source. This electric discharge is confined in reactor plan-parallel geometry. This reactor is filled by Argon monatomic gas. Our continuum model the order two is composed the first three moments the Boltzmann's equations coupled with Poisson's equation by self consistent method. These transport equations are discretized by the finite volumes method. The equations system is resolved by a new technique, it is about the N-BEE explicit scheme using the time splitting method.

  14. Electron-beam sustained glow discharge in a N{sub 2}+CO gas mixture at cryogenic temperature

    Energy Technology Data Exchange (ETDEWEB)

    Azharonok, V V; Filatova, I I; Chubrik, N I; Shimanovich, V D [Belarussian Academy of Sciences, Minsk (Belarus). Inst. of Molecular and Atomic Physics; Gurashvili, V A; Kuzmin, V N; Turkin, N G; Vaselenok, A A [Troitsk Institute of Innovative and Fusion Research (Russian Federation)

    1997-12-31

    A quasi-continuum electron-beam sustained glow discharge in a flow of N{sub 2} + CO gas mixture at cryogenic temperature was studied by emission spectroscopy. The effective values of electron-ion recombination and rate of electron adhesion to electronegative molecules (Fe(CO){sub 5}, Ni(CO){sub 4}, H{sub 2}O) present in the discharge were determined in dependence on the reduced electric field strength E/N. (author). 1 tab., 2 figs., 5 refs.

  15. Development of soft ionization using direct current pulse glow discharge plasma source in mass spectrometry for volatile organic compounds analysis

    Science.gov (United States)

    Nunome, Yoko; Kodama, Kenji; Ueki, Yasuaki; Yoshiie, Ryo; Naruse, Ichiro; Wagatsuma, Kazuaki

    2018-01-01

    This study describes an ionization source for mass analysis, consisting of glow discharge plasma driven by a pulsed direct-current voltage for soft plasma ionization, to detect toxic volatile organic compounds (VOCs) rapidly and easily. The novelty of this work is that a molecular adduct ion, in which the parent molecule attaches with an NO+ radical, [M + NO]+, can be dominantly detected as a base peak with little or no fragmentation of them in an ambient air plasma at a pressure of several kPa. Use of ambient air as the discharge plasma gas is suitable for practical applications. The higher pressure in an ambient air discharge provided a stable glow discharge plasma, contributing to the soft ionization of organic molecules. Typical mass spectra of VOCs toluene, benzene, o-xylene, chlorobenzene and n-hexane were observed as [M + NO]+ adduct ion whose peaks were detected at m/z 122, 108, 136, 142 and 116, respectively. The NO generation was also confirmed by emission bands of NO γ-system. The ionization reactions were suggested, such that NO+ radical formed in an ambient air discharge could attach with the analyte molecule.

  16. Monte Carlo simulation of fast electrons and heavy particles in the CDS of nitrogen dc glow discharge

    International Nuclear Information System (INIS)

    Yu, W.; Zhang, L.Z.; Wang, J.L.; Han, L.; Fu, G.S.

    2001-01-01

    The characteristics of fast electrons (e - ) and heavy particles (N 2 + , N + , N 2f , N f ) in the cathode dark space (CDS) of nitrogen dc glow discharge are simultaneously studied by Monte Carlo simulation. The calculated energy and angular distributions of these particles at different positions from the cathode provide a clear picture of their transport behaviours within the CDS. The density and mean energy of these particles indicate that the electrons and the atomic ions (N + ) are the main high-energy species and the molecular ions (N 2 + ) are the major ions in the CDS. It can be seen from the energy distributions of the bombarding particles at the cathode surface that the molecular ions and the fast atoms (N f ) are the main active species participating in the cathode nitride material synthesis process. The influence of the backscattering of the electrons from the negative glow to the CDS is also investigated. All the calculated results provide good information on the spatial characteristics of the particles considered in this paper and also their internal connections in the CDS of nitrogen dc glow discharge. (author)

  17. Etching of UO2 in NF3 RF Plasma Glow Discharge

    International Nuclear Information System (INIS)

    John M. Veilleux

    1999-01-01

    A series of room temperature, low pressure (10.8 to 40 Pa), low power (25 to 210 W) RF plasma glow discharge experiments with UO 2 were conducted to demonstrate that plasma treatment is a viable method for decontaminating UO 2 from stainless steel substrates. Experiments were conducted using NF 3 gas to decontaminate depleted uranium dioxide from stainless-steel substrates. Depleted UO 2 samples each containing 129.4 Bq were prepared from 100 microliter solutions of uranyl nitrate hexahydrate solution. The amorphous UO 2 in the samples had a relatively low density of 4.8 gm/cm 3 . Counting of the depleted UO 2 on the substrate following plasma immersion was performed using liquid scintillation counting with alpha/beta discrimination due to the presence of confounding beta emitting daughter products, 234 Th and 234 Pa. The alpha emission peak from each sample was integrated using a gaussian and first order polynomial fit to improve quantification. The uncertainties in the experimental measurement of the etched material were estimated at about ± 2%. Results demonstrated that UO 2 can be completely removed from stainless-steel substrates after several minutes processing at under 200 W. At 180 W and 32.7 Pa gas pressure, over 99% of all UO 2 in the samples was removed in just 17 minutes. The initial etch rate in the experiments ranged from 0.2 to 7.4 microm/min. Etching increased with the plasma absorbed power and feed gas pressure in the range of 10.8 to 40 Pa. A different pressure effect on UO 2 etching was also noted below 50 W in which etching increased up to a maximum pressure, approximately23 Pa, then decreased with further increases in pressure

  18. ULTRAVIOLET INDUCED MOTION OF A FLUORESCENT DUST CLOUD IN AN ARGON DIRECT CURRENT GLOW DISCHARGE PLASMA

    Energy Technology Data Exchange (ETDEWEB)

    Hvasta, M.G.; and Zwicker, A.

    2008-01-01

    Dusty plasmas consist of electrons, ions, neutrals and nm-μm sized particles commonly referred to as dust. In man-made plasmas this dust may represent impurities in a tokamak or plasma etching processing. In astrophysical plasmas this dust forms structures such as planetary rings and comet tails. To study dusty plasma dynamics an experiment was designed in which a 3:1 silica (<5 μm diameter) and fl uorescent dust mixture was added to an argon DC glow discharge plasma and exposed to UV radiation. This fl uorescent lighting technique offers an advantage over laser scattering (which only allows two-dimensional slices of the cloud to be observed) and is simpler than scanning mirror techniques or particle image velocimetry. Under typical parameters (P=150 mTorr, V anode= 100 V, Vcathode= -400 V, Itotal < 2mA) when the cloud is exposed to the UV light (100W, λ = 365 nm) the mixture fl uoresces, moves ~2mm towards the light source and begins rotating in a clockwise manner (as seen from the cathode). By calibrating a UV lamp and adjusting the relative intensity of the UV with a variable transformer it was found that both translational and rotational velocities are a function of UV intensity. Additionally, it was determined that bulk cloud rotation is not seen when the dust tray is not grounded while bulk translation is. This ongoing experiment represents a novel way to control contamination in man-made plasmas and a path to a better understanding of UV-bathed plasma systems in space..

  19. Preliminary fluid channel design and thermal-hydraulic analysis of glow discharge cleaning permanent electrode

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Lijun, E-mail: cailj@swip.ac.cn [Southwestern Institute of Physics, Chengdu (China); Lin, Tao; Wang, Yingqiao; Wang, Mingxu [Southwestern Institute of Physics, Chengdu (China); Maruyama, So; Yang, Yu; Kiss, Gabor [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France)

    2016-11-01

    Highlights: • The plasma facing closure cap has to survive after 30,000 thermal heat load cycles. • 0.35 MW/m2 radiation heat load plus nuclear heat load are very challenging for stainless steel. • Multilayer structure has been designed by using advanced welding and drilling technology to solve the neutron heating problem. • Accurate volumetric load application in analysis model by CFX has been mastered. - Abstract: Glow discharge cleaning (GDC) shall be used on ITER device to reduce and control impurity and hydrogenic fuel out-gassing from in-vessel plasma facing components. After first plasma, permanent electrode (PE) will be used to replace Temporary Electrode (TE) for subsequent operation. Two fundamental scenarios i.e., GDC and Plasma Operation State (POS) should be considered for electrode design, which requires the heat load caused by plasma radiation and neutron heating must be taken away by cooling water flowing inside the electrode. In this paper, multilayer cooling channels inside PE are preliminarily designed, and snakelike route in each layer is adopted to improve the heat exchange. Detailed thermal-hydraulic analyses have been done to validate the design feasibility or rationality. The analysis results show that during GDC the cooling water inlet and outlet temperature difference is far less than the allowable temperature rise under water flow rate 0.15 kg/s compromised by many factors. For POS, the temperature rise and pressure drop are within the design goals, but high thermal stress occurs on the front surface of closure cap of electrode. After several iterations of optimization of the closure cap, the equivalent strain range after 30,000 loading cycles for POS is well below 0.3% design goals.

  20. Glow discharge mass spectrometry study of chemical impurities diffusion in zirconium oxide layers

    International Nuclear Information System (INIS)

    Actis-Dato, L.O.

    2000-02-01

    In the Pressurised Water Reactors (PWR) the primary cooling system is water at 350 deg C and 16 Mpa. In these extreme conditions the corrosion of the out-of-pile components of the reactor and in particular of the Zircaloy cladding containing the nuclear fuel pellets is accelerated. The formation of a growing oxide layer is observed on the elements of the nuclear reactor core. When the thickness of the oxide layer reaches a critical value, problems like structural malfunction and material failure can occur. At this stage the danger of the release of radioactivity in the coolant becomes effective. In this work a glow discharge mass spectrometer is used to study the diffusion of impurities like lithium, zinc and boron in oxide layers growing on Zircaloy samples. After a brief description of the different technique used the preparation and analysis of Zircaloy samples on which oxide layers of different thickness have been produced will be described. The analysis of these samples will allow the determination and evaluation the depth profiles of the impurities absorbed by the oxide. The analysis of the shape of the crater produced during the mass spectrometric analysis will give additional informations on the quality of the results obtained. The technique developed will finally be applied to the study of samples produced during reactor operation under real irradiation conditions. The results obtained show a lithium intake in the oxide layer and confirm the beneficial effect on the corrosion produced by boron. The influence of zinc on the corrosion behaviour of Zircaloy has not been established. The technique developed has also shown interesting capabilities concerning the analysis of irradiated samples. (author)

  1. Effects of rf power on chemical composition and surface roughness of glow discharge polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ling; He, Xiaoshan; Chen, Guo; Wang, Tao; Tang, Yongjian; He, Zhibing, E-mail: hezhibing802@163.com

    2016-03-15

    Graphical abstract: - Highlights: • The growth mechanism of defects in GDP films was studied upon plasma diagnosis. • Increasing rf power enhanced the etching effects of smaller-mass species. • The “void” defect was caused by high energy hydrocarbons bombardment on the surface. • The surface roughness was only 12.76 nm, and no “void” defect was observed at 30 W. - Abstract: The glow discharge polymer (GDP) films for laser fusion targets were successfully fabricated by plasma enhanced chemical vapor deposition (PECVD) at different radio frequency (rf) powers. The films were deposited using trans-2-butene (T{sub 2}B) mixed with hydrogen as gas sources. The composition and state of plasma were diagnosed by quadrupole mass spectrometer (QMS) and Langmuir probe during the deposition process. The composition, surface morphology and roughness were investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and white-light interferometer (WLI), respectively. Based on these observation and analyses, the growth mechanism of defects in GDP films were studied. The results show that, at low rf power, there is a larger probability for secondary polymerization and formation of multi-carbon C-H species in the plasma. In this case, the surface of GDP film turns to be cauliflower-like. With the increase of rf power, the degree of ionization is high, the relative concentration of smaller-mass hydrocarbon species increases, while the relative concentration of larger-mass hydrocarbon species decreases. At higher rf power, the energy of smaller-mass species are high and the etching effects are strong correspondingly. The GDP film's surface roughness shows a trend of decrease firstly and then increase with the increasing rf power. At rf power of 30 W, the surface root-mean-square roughness (Rq) drops to the lowest value of 12.8 nm, and no “void” defect was observed.

  2. Opto-galvanic effect on degenerate magnetic states of sputtered atoms in a glow discharge

    International Nuclear Information System (INIS)

    Zhechev, D; Steflekova, V

    2014-01-01

    The opto-galvanic response of some degenerate states of sputtered atoms to linearly- and circularly polarize light is studied. On the same optical transition both time-resolved- and amplitude opto-galvanic signals are found depending on the polarizations of light absorbed. The latter induces galvanic responses differing in opto-galvanic efficiency, time-evolution and sensitivity to discharge current and laser power. The differences are ascribed to the rate constants of the decay processes, characterizing aligned and oriented atoms

  3. V-I curves and plasma parameters in a high density DC glow discharge generated by a current-source

    International Nuclear Information System (INIS)

    Granda-Gutierrez, E E; Lopez-Callejas, R; Piedad-Beneitez, A de la; BenItez-Read, J S; Pacheco-Sotelo, J O; Pena-Eguiluz, R; A, R Valencia; Mercado-Cabrera, A; Barocio, S R

    2008-01-01

    Nitrogen DC glow discharges, conducted in a cylindrical geometry, have been characterized using a new current-source able to provide 10 -3 - 3 A for the sustainment of the discharge, instead of a conventional voltage-source. The V-I characteristic curves obtained from these discharges were found to fit the general form i(v) = A(p)v k(p) , whereby the plasma itself can be modeled as a voltage-controlled current-source. We conclude that the fitting parameters A and k, which mainly depend on the gas pressure p, are strongly related to the plasma characteristics, so much so that they can indicate the pressure interval in which the maximum plasma density is located, with values in the order of 10 16 m -3 at reduced discharge potential (300-600 V) and low working pressure (10 -1 - 10 1 Pa)

  4. Investigation of hydrophobic substrates for solution residue analysis utilizing an ambient desorption liquid sampling-atmospheric pressure glow discharge microplasma.

    Science.gov (United States)

    Paing, Htoo W; Marcus, R Kenneth

    2018-03-12

    A practical method for preparation of solution residue samples for analysis utilizing the ambient desorption liquid sampling-atmospheric pressure glow discharge optical emission spectroscopy (AD-LS-APGD-OES) microplasma is described. Initial efforts involving placement of solution aliquots in wells drilled into copper substrates, proved unsuccessful. A design-of-experiment (DOE) approach was carried out to determine influential factors during sample deposition including solution volume, solute concentration, number of droplets deposited, and the solution matrix. These various aspects are manifested in the mass of analyte deposited as well as the size/shape of the product residue. Statistical analysis demonstrated that only those initial attributes were significant factors towards the emission response of the analyte. Various approaches were investigated to better control the location/uniformity of the deposited sample. Three alternative substrates, a glass slide, a poly(tetrafluoro)ethylene (PTFE) sheet, and a polydimethylsiloxane (PDMS)-coated glass slide, were evaluated towards the microplasma analytical performance. Co-deposition with simple organic dyes provided an accurate means of determining the location of the analyte with only minor influence on emission responses. The PDMS-coated glass provided the best performance by virtue of its providing a uniform spatial distribution of the residue material. This uniformity yielded an improved limits of detection by approximately 22× for 20 μL and 4 x for 2 μL over the other two substrates. While they operate by fundamentally different processes, this choice of substrate is not restricted to the LS-APGD, but may also be applicable to other AD methods such as DESI, DART, or LIBS. Further developments will be directed towards a field-deployable ambient desorption OES source for quantitative analysis of microvolume solution residues of nuclear forensics importance.

  5. Cathode fall thickness of abnormal glow discharges between parallel-plane electrodes in different radii at low pressure

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Yangyang; Luo, Haiyun; Zou, Xiaobing; Wang, Xinxin, E-mail: wangxx@tsinghua.edu.cn [Department of Electrical Engineering, Tsinghua University, Beijing 100084 (China)

    2015-02-15

    In order to investigate the influence of electrode radius on the characteristics of cathode fall thickness, experiments of low-pressure (20 Pa ≤ p ≤ 30 Pa) abnormal glow discharge were carried out between parallel-plane electrodes in different radii keeping gap distance unchanged. Axial distributions of light intensity were obtained from the discharge images captured using a Charge Coupled Device camera. The assumption that the position of the negative glow peak coincides with the edge of cathode fall layer was verified based on a two-dimensional model, and the cathode fall thicknesses, d{sub c}, were calculated from the axial distributions of light intensity. It was observed that the position of peak emission shifts closer to the cathode as current or pressure grows. The dependence of cathode fall thickness on the gas pressure and normalized current J/p{sup 2} was presented, and it was found that for discharges between electrodes in large radius the curves of pd{sub c} against J/p{sup 2} were superimposed on each other, however, this phenomenon will not hold for discharges between the smaller electrodes. The reason for this phenomenon is that the transverse diffusions of charged particles are not the same in two gaps between electrodes with different radii.

  6. Applicability of the Child-Langmuir laws versions for describing the glow discharge cathode sheath in CO2

    Science.gov (United States)

    Lisovskiy, Valeriy; Krol, Hennadii; Osmayev, Ruslan; Yegorenkov, Vladimir

    2016-09-01

    This work is devoted to the determination of the law that may be applicable to the description of the cathode sheath in CO2. To this end three versions of the Child-Langmuir law have been considered - a collision free one (for the ions moving through a cathode sheath without collisions with gas molecules) as well as two collision- related versions- one for a constant mean free path of positive ions and one for a constant mobility of positive ions. The current-voltage characteristics and the cathode sheath thickness of the glow discharge in carbon oxide have been simultaneously measured in the pressure range from 0.05 to 1 Torr and with the discharge current values up to 80 mA. The inter-electrode distance has been chosen such that the discharge consists only of the cathode sheath and a small portion of the negative glow, i.e. the experiments have been performed in short tubes. In this case the voltage drop across the cathode sheath is equal approximately to the voltage drop across the electrodes. In the whole range of the discharge conditions we have studied the cathode sheath characteristics are found to obey correctly only to the Child-Langmuir law version with a constant ion mobility. The reason for this phenomenon may be related with a significant conversion of carbon dioxide molecules.

  7. Use of a glow discharge lamp as an excitation source in emission spectrometry. Application to concentration gradients

    International Nuclear Information System (INIS)

    Delarue, G.; Pichat, R.

    1978-01-01

    The principle of the method is to take the material studied as a cathode of a discharge tube of very small volume: it is etched without fusion by bombardment with the rare gas ions participating in the discharge. The atoms of the sputtered metal are excited in the plasma existing between the electrodes and by measurement of the intensity of spectral lines one can determine the concentration of the elements in the sample. The principal advantage of the glow discharge lamp is to obtain the profile of concentration gradients: indeed by means of ionic bombardment, there is a gradual erosion of the sample with a constant speed. At every moment the composition of the plasma corresponds to the composition of the level which is etched. This technique is used to study diffusion gradients of carbon in carburized and not carburized steels [fr

  8. Simulation of convection-stabilized low-current glow and arc discharges in atmospheric-pressure air

    International Nuclear Information System (INIS)

    Naidis, G V

    2007-01-01

    A two-dimensional model of stationary convection-stabilized low-current glow and arc discharge columns in atmospheric-pressure air is developed which accounts for deviation of the plasma state from the local thermodynamic equilibrium (LTE). In addition to equations of energy, continuity and momentum (analogous to those used in LTE arc models), the non-LTE model includes balance equations for plasma species and for the vibrational energy of nitrogen molecules. The kinetic scheme is used which was developed recently for the simulation of low-current wall-stabilized discharges in air. Results of calculation of discharge parameters over a wide current range are presented. It is shown that the non-equilibrium effects are substantial at currents lower than ∼ 100 mA. The calculated plasma parameters agree with available experimental data

  9. Study of the excitation mechanisms of the second positive system in the negative glow of a N2-Ar discharge

    International Nuclear Information System (INIS)

    Isola, L; Lopez, M; Gomez, B J

    2011-01-01

    In an Ar-N 2 discharge, the high excitation transfer from Ar( 3 P 2,0 ) to N 2 produces an overpopulation of the high rotational levels of the bands of the second positive system (SPS), and so the spectra interpretation is not straightforward. This paper presents a fit function for the SPS bands measured in Ar-N 2 , which allows us to study the excitation process contributions to the N 2 (C) level. The procedure was tested in the negative glow of a pulsed Ar-N 2 discharge at a pressure of 2.5 Torr, for different mixture concentrations. In this discharge, through the fitting, it was possible to calculate the variation of the N 2 (C) densities produced by different excitation processes as well as the variation of Ar metastable density.

  10. Glow discharge mass spectrometric analysis of nickel-based heat-resisting alloys

    International Nuclear Information System (INIS)

    Itoh, Shinji; Yamaguchi, Hitoshi; Kobayashi, Takeshi; Hasegawa, Ryosuke

    1996-01-01

    GD-MS analysis of nickel-based heat-resisting alloys has been performed using a VG 9000 glow discharge (GD) mass spectrometer. Concentrations of not only alloying elements (Al, Si, Ti, V, Cr, Mn, Fe, Co, Cu, Y, Nb, Mo and W) but also trace elements (B, C, Mg, P, S, Zn, Ga, As, Zr, Cd, Sn, Sb, Te, Pb and Bi) were successfully determined in disk shaped samples. The examination of spectral interference confirmed the following. The influence of manganese argide ( 55 Mn 40 Ar + ) on the ion beam intensity of 95 Mo + was negligible because manganese content of the alloys is usually less than 1 mass%. Mass spectra of 31 P + and 32 S + may be affected by the spectral interference of 62 Ni 2+ and 64 Ni 2+ , respectively, due to the matrix element. However, these ion species were sufficiently separated at the mass resolution 5000 (m/Δm, at 5% peak height) used in this study. Relative sensitivity factors (RSFs) were determined by analyzing standard reference materials: JAERI CRMs, a NIST SRM, a BS CRM, BCS CRMs and the alloys prepared in our Institute. The average RSF-values obtained for Ni=1 were 0.436 for Al, 0.826 for Si, 0.281 for Ti, 0.375 for V, 1.480 for Cr, 1.122 for Mn, 0.754 for Fe, 0.653 for Co, 3.321 for Cu, 0.303 for Y, 0.436 for Nb, 0.862 for Mo, 0.935 for Ta and 1.052 for W. The analytical accuracy (σ d ) obtained was comparable to that of FP-XRF analysis, except for chromium and iron determinations. Relative standard deviations (RSDs) of five replicate measurements were within about 2.5%, except for phosphorus (P; 0.003 mass%, RSD; 3.31%) and sulfur (S; 0.005 mass%, RSD; 3.08%). GD-MS analytical values for ODS MA6000 alloy were obtained using a RSF correction program, and the values were in good agreement with those obtained by FP-XRF and by chemical analysis (author)

  11. Development of realtime monitoring technology for laser photoreaction product - Development of glow discharge-mass spectrometry (GD-MS) hybrid techniques for trace analysis of refractory elements

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Chun [Kyungnam University, Masan (Korea); Kim, Ha Suck [Seoul National University, Seoul (Korea); Kim, Hyo Jin [Dongduk Women' s University, Seoul (Korea)

    2000-04-01

    This research is focusing on development of hybrid techniques of glow discharge-mass spectrometry for the trace analysis of refractory elements. At first, we developed a glow discharge(GD) ionization cell and its characteristics was investigated. The new GD cell was designed based on direct current hollow cathode glow discharge and it is used for quadrupole mass analyzer and time-of-flight mass analyzer. Currently, GD-quadrupole mass spectrometry is working for the analysis of refractory elements. The experimental results show relatively good for trace analysis. In addition, ion mobile spectrometry using plasma and liquid discharge technique were investigated for the analysis of refractory elements and both techniques need more investigation to deduce the their usefulness. 30 refs., 67 figs., 4 tabs. (Author)

  12. Redeposition of sputtered material in a glow-discharge lamp measured by means of an ion microprobe mass analyser

    International Nuclear Information System (INIS)

    Ferreira, N.P.; Bueger, P.A.

    1978-01-01

    The redeposition of sputtered material on the target in a Grimm-type glow-discharge lamp was studied by means of an ion microprobe mass analyser (IMMA) using 16 O 2 + ions as bombarding species. The target was an aluminium disc with a cylindrical copper insertion, one mm in diameter. The lamp was operated at currents of 50 mA and 100 mA and a voltage of 1200 V. It is estimated that 17% of the copper atoms sputtered are redeposited and may be resputtered. (orig.) [de

  13. Selective excitation of singly-ionized silver emission lines by Grimm glow discharge plasmas using several different plasma gases

    International Nuclear Information System (INIS)

    Wagatsuma, K.

    1996-01-01

    The relative intensities of silver emission lines from Grimm glow discharge plasmas were investigated in the wavelength range from 160 to 600 nm when using different plasma gases. It was characteristic of the plasma excitation that the spectral patterns were strongly dependent on the nature of the plasma gas employed. Intense emission lines of silver ion were observed when argon-helium mixed gases were employed as the plasma gas. Selective excitation of the ionic lines could be principally attributed to the charge transfer collisions between silver atoms and helium ions. (orig.)

  14. Laser-induced fluorescences due to quadrupole moment transition and Stark effect in a He glow discharge

    International Nuclear Information System (INIS)

    Sakai, Hisashi; Takiyama, Ken; Kimura, Masahiko; Yamasaki, Motokuni; Fujita, Toshiaki; Oda, Toshiatsu; Kawasaki, Ken.

    1993-01-01

    The electric quadrupole moment transition and the Stark effect are investigated in a He hollow cathode discharge with laser-induced fluorescence method. It is shown that the forbidden transition from 2 1 S to 3 1 D in the negative glow is dominantly due to the quadrupole moment transition. This absorption coefficient is obtained from the laser-induced fluorescence intensity measurement in which the collisional transfers are taken into account. The result agrees with the theoretical coefficient. In the cathode dark space the fluorescence due to the Stark effect is also observed. Spatial distribution of the fluorescence is discussed, compared with the electric field distribution in the dark space. (author)

  15. Quantitative determination of major and minor elements in alloys by emission spectroscopy using Grimm glow discharge lamps

    International Nuclear Information System (INIS)

    Fonseca, T.C.O. da.

    1987-01-01

    A rapid and simple analytical method for the determination of major, minor and trace elements in alloys, using the Grimm glow discharge lamp as spectroscopic excitation source is studied. Alloys of copper, aluminium, stainless and carbon steel, including the determination of the elements: Cu, Fe, Al, Ni, Cr, Mn, Nb, Si, Mo, Ti, V, Zn, Mg and Co are analyzed. Some parameters as optimal entrance slit position, pre-burning time and integration time of the analytical signal, current, argon pressure, tension pulse and applied power are studied. (M.J.C.) [pt

  16. Study on the effect of hydrogen addition on the variation of plasma parameters of argon-oxygen magnetron glow discharge for synthesis of TiO2 films

    Directory of Open Access Journals (Sweden)

    Partha Saikia

    2016-04-01

    Full Text Available We report the effect of hydrogen addition on plasma parameters of argon-oxygen magnetron glow discharge plasma in the synthesis of H-doped TiO2 films. The parameters of the hydrogen-added Ar/O2 plasma influence the properties and the structural phases of the deposited TiO2 film. Therefore, the variation of plasma parameters such as electron temperature (Te, electron density (ne, ion density (ni, degree of ionization of Ar and degree of dissociation of H2 as a function of hydrogen content in the discharge is studied. Langmuir probe and Optical emission spectroscopy are used to characterize the plasma. On the basis of the different reactions in the gas phase of the magnetron discharge, the variation of plasma parameters and sputtering rate are explained. It is observed that the electron and heavy ion density decline with gradual addition of hydrogen in the discharge. Hydrogen addition significantly changes the degree of ionization of Ar which influences the structural phases of the TiO2 film.

  17. Dynamic Contraction of the Positive Column of a Self-Sustained Glow Discharge in Molecular Gas Flow

    Science.gov (United States)

    Shneider, Mikhail

    2014-10-01

    Contraction of the gas discharge, when current contracts from a significant volume of weakly ionized plasma into a thin arc channel, was attracted attention of scientists for more than a century. Studies of the contraction (also called constriction) mechanisms, besides carrying interesting science, are of practical importance, especially when contraction should be prevented. A set of time-dependent two-dimensional equations for the non-equilibrium weakly-ionized nitrogen/ air plasma is formulated. The process is described by a set of time-dependent continuity equations for the electrons, positive and negative ions; gas and vibrational temperature; by taking into account the convective heat and plasma losses by the transverse flux. Transition from the uniform to contracted state was analyzed. It was shown that such transition experiences a hysteresis, and that the critical current of the transition increases when the pressure (gas density) drops. Possible coexistence of the contracted and uniform state of the plasma in the discharge where the current flows along the density gradient of the background gas was discussed. In this talk the problems related to the dynamic contraction of the current channel inside a quasineutral positive column of a self-sustained glow discharge in molecular gas in a rectangular duct with convection cooling will be discussed. Study presented in this talk was stimulated by the fact that there are large number of experiments on the dynamic contraction of a glow discharge in nitrogen and air flows and a many of possible applications. Similar processes play a role in the powerful gas-discharge lasers. In addition, the problem of dynamic contraction in the large volume of non-equilibrium weakly ionized plasma is closely related to the problem of streamer to leader transitions in lightning and blue jets.

  18. In situ glow discharge plasma electrolytic synthesis of reduced TiO2 for enhanced visible light photocatalysis

    Science.gov (United States)

    Feng, Guang; Wu, Botao; Qayyum Khan, Abdul; Zeng, Heping

    2018-05-01

    Reduced titanium dioxide (TiO2‑x) due to its extraordinary visible light absorption has been widely investigated in photodegradation and water splitting nowadays. However, conventional routes to synthesize reduced TiO2 usually demand multiple preparation steps, harsh controlled conditions or expensive facilities. Here we developed a single-step in situ approach to prepare the gray TiO2‑x nanoparticles (sub-10 nm) effectively by the glow discharge plasma electrolysis (GDPE) under atmospheric pressure. The co-existence of self-doped oxygen vacancies and Ti3+ in the generated TiO2‑x nanoparticles is demonstrated by electron paramagnetic resonance (EPR). The tunable ratio of bulk/surface defect can be realized by controlling the glow discharge power directly. It should be noticed that Ti3+ in the synthesized TiO2‑x are quite stable in ambient air. The UV–vis spectra of gray TiO2‑x show an enhanced visible light absorption, which leads to high visible-light photocatalytic activity. Moreover, the as-prepared TiO2‑x after 6 months storage still shows excellent stability during photocatalytic reactions. Owing to its simplicity and effectivity, this preparation method with GDPE should provide a large-scale production for TiO2‑x with high photoactivity.

  19. The design and characteristics of direct current glow discharge atomic emission source operated with plain and hollow cathodes

    International Nuclear Information System (INIS)

    Qayyum, A.; Mahmood, M.I.

    2008-01-01

    A compact direct current glow discharge atomic emission source has been designed and constructed for analytical applications. This atomic emission source works very efficiently at a low-input electrical power. The design has some features that make it distinct from that of the conventional Grimm glow discharge source. The peculiar cathode design offered greater flexibility on size and shape of the sample. As a result the source can be easily adopted to operate in Plain or Hollow Cathode configuration. I-V and spectroscopic characteristics of the source were compared while operating it with plain and hollow copper cathodes. It was observed that with hollow cathode, the source can be operated at a less input power and generates greater Cu I and Cu II line intensities. Also, the intensity of Cu II line rise faster than Cu I line with argon pressure for both cathodes. But the influence of pressure on Cu II lines was more significant when the source is operated with hollow cathode

  20. Numerical simulation of an oxygen-fed wire-to-cylinder negative corona discharge in the glow regime

    Energy Technology Data Exchange (ETDEWEB)

    Yanallah, K; Pontiga, F [Dpt. Fisica Aplicada II, Universidad de Sevilla (Spain); Castellanos, A [Dpt. Electronica y Electromagnetismo, Universidad de Sevilla (Spain)

    2011-02-09

    Negative glow corona discharge in flowing oxygen has been numerically simulated for a wire-to-cylinder electrode geometry. The corona discharge is modelled using a fluid approximation. The radial and axial distributions of charged and neutral species are obtained by solving the corresponding continuity equations, which include the relevant plasma-chemical kinetics. Continuity equations are coupled with Poisson's equation and the energy conservation equation, since the reaction rate constants may depend on the electric field and temperature. The experimental values of the current-voltage characteristic are used as input data into the numerical calculations. The role played by different reactions and chemical species is analysed, and the effect of electrical and geometrical parameters on ozone generation is investigated. The reliability of the numerical model is verified by the reasonable agreement between the numerical predictions of ozone concentration and the experimental measurements.

  1. Electron energy distribution function in the positive column of a neon glow discharge using the black wall approximation

    International Nuclear Information System (INIS)

    Al-Hawat, Sh; Naddaf, M

    2005-01-01

    The electron energy distribution function (EEDF) was determined from the second derivative of the I-V Langmuir probe characteristics and, thereafter, theoretically calculated by solving the plasma kinetic equation, using the black wall (BW) approximation, in the positive column of a neon glow discharge. The pressure has been varied from 0.5 to 4 Torr and the current from 10 to 30 mA. The measured electron temperature, density and electric field strength were used as input data for solving the kinetic equation. Comparisons were made between the EEDFs obtained from experiment, the BW approach, the Maxwellian distribution and the Rutcher solution of the kinetic equation in the elastic energy range. The best conditions for the BW approach are found to be under the discharge conditions: current density j d = 4.45 mA cm -2 and normalized electric field strength E/p = 1.88 V cm -1 Torr -1

  2. Electron energy distribution function in the positive column of a neon glow discharge using the black wall approximation

    Science.gov (United States)

    Al-Hawat, Sh; Naddaf, M.

    2005-04-01

    The electron energy distribution function (EEDF) was determined from the second derivative of the I-V Langmuir probe characteristics and, thereafter, theoretically calculated by solving the plasma kinetic equation, using the black wall (BW) approximation, in the positive column of a neon glow discharge. The pressure has been varied from 0.5 to 4 Torr and the current from 10 to 30 mA. The measured electron temperature, density and electric field strength were used as input data for solving the kinetic equation. Comparisons were made between the EEDFs obtained from experiment, the BW approach, the Maxwellian distribution and the Rutcher solution of the kinetic equation in the elastic energy range. The best conditions for the BW approach are found to be under the discharge conditions: current density jd = 4.45 mA cm-2 and normalized electric field strength E/p = 1.88 V cm-1 Torr-1.

  3. Numerical simulation of an oxygen-fed wire-to-cylinder negative corona discharge in the glow regime

    Science.gov (United States)

    Yanallah, K.; Pontiga, F.; Castellanos, A.

    2011-02-01

    Negative glow corona discharge in flowing oxygen has been numerically simulated for a wire-to-cylinder electrode geometry. The corona discharge is modelled using a fluid approximation. The radial and axial distributions of charged and neutral species are obtained by solving the corresponding continuity equations, which include the relevant plasma-chemical kinetics. Continuity equations are coupled with Poisson's equation and the energy conservation equation, since the reaction rate constants may depend on the electric field and temperature. The experimental values of the current-voltage characteristic are used as input data into the numerical calculations. The role played by different reactions and chemical species is analysed, and the effect of electrical and geometrical parameters on ozone generation is investigated. The reliability of the numerical model is verified by the reasonable agreement between the numerical predictions of ozone concentration and the experimental measurements.

  4. Numerical simulation of an oxygen-fed wire-to-cylinder negative corona discharge in the glow regime

    International Nuclear Information System (INIS)

    Yanallah, K; Pontiga, F; Castellanos, A

    2011-01-01

    Negative glow corona discharge in flowing oxygen has been numerically simulated for a wire-to-cylinder electrode geometry. The corona discharge is modelled using a fluid approximation. The radial and axial distributions of charged and neutral species are obtained by solving the corresponding continuity equations, which include the relevant plasma-chemical kinetics. Continuity equations are coupled with Poisson's equation and the energy conservation equation, since the reaction rate constants may depend on the electric field and temperature. The experimental values of the current-voltage characteristic are used as input data into the numerical calculations. The role played by different reactions and chemical species is analysed, and the effect of electrical and geometrical parameters on ozone generation is investigated. The reliability of the numerical model is verified by the reasonable agreement between the numerical predictions of ozone concentration and the experimental measurements.

  5. Isotope exchange experiments on TEXTOR and TORE SUPRA using Ion Cyclotron Wall Conditioning and Glow Discharge Conditioning

    International Nuclear Information System (INIS)

    Wauters, T.; Douai, D.; Lyssoivan, A.; Philipps, V.; Bremond, S.; Freisinger, M.; Kreter, A.; Lombard, G.; Marchuk, O.; Mollard, P.; Paul, M.K.; Pegourie, B.; Reimer, H.; Sergienko, G.; Tsitrone, E.; Vervier, M.; Van Wassenhove, G.; Wuenderlich, D.; Van Schoor, M.; Van Oost, G.

    2011-01-01

    This contribution reports on isotope exchange studies with both Ion Cyclotron Wall Conditioning (ICWC) and Glow Discharge Conditioning (GDC) in TEXTOR and TORE SUPRA. The discharges have been carried out in H 2 , D 2 (ICWC and GDC) and He/H 2 mixtures (ICWC). The higher reionization probability in ICWC compared to GDC, following from the 3 to 4 orders of magnitude higher electron density, leads to a lower pumping efficiency of wall desorbed species. GDC has in this analysis (5-10) times higher removal rates of wall desorbed species than ICWC, although the wall release rate is 10 times higher in ICWC. Also the measured high retention during ICWC can be understood as an effect of the high reionization probability. The use of short RF pulses (∼1 s) followed by a larger pumping time significantly improves the ratio of implanted over recovered particles, without severely lowering the total amount of removed particles.

  6. Etching of uranium dioxide in nitrogen trifluoride RF plasma glow discharge

    Science.gov (United States)

    Veilleux, John Mark

    1999-10-01

    A series of room temperature, low pressure (10.8 to 40 Pa), low power (25 to 210 W) RF plasma glow discharge experiments with UO2 were conducted to demonstrate that plasma treatment is a viable method for decontaminating UO2 from stainless steel substrates. Experiments were conducted using NF3 gas to decontaminate depleted uranium dioxide from stainless-steel substrates. Results demonstrated that UO2 can be completely removed from stainless-steel substrates after several minutes processing at under 200 W. At 180 W and 32.7 Pa gas pressure, over 99% of all UO2 in the samples was removed in just 17 minutes. The initial etch rate in the experiments ranged from 0.2 to 7.4 mum/min. Etching increased with the plasma absorbed power and feed gas pressure in the range of 10.8 to 40 Pa. A different pressure effect on UO2 etching was also noted below 50 W in which etching increased up to a maximum pressure, ˜23 Pa, then decreased with further increases in pressure. A computer simulation, CHEMKIN, was applied to predict the NF3 plasma species in the experiments. The code was validated first by comparing its predictions of the NF3 plasma species with mass spectroscopy etching experiments of silicon. The code predictions were within +/-5% of the measured species concentrations. The F atom radicals were identified as the primary etchant species, diffusing from the bulk plasma to the UO2 surface and reacting to form a volatile UF6, which desorbed into the gas phase to be pumped away. Ions created in the plasma were too low in concentration to have a major effect on etching, but can enhance the etch rate by removing non-volatile reaction products blocking the reaction of F with UO2. The composition of these non-volatile products were determined based on thermodynamic analysis and the electronic structure of uranium. Analysis identified possible non-volatile products as the uranium fluorides, UF2-5, and certain uranium oxyfluorides UO2F, UO2F2, UOF3, and UOF 4 which form over the

  7. Depth-profile analysis of thermoelectric layers on Si wafers by pulsed r.f. glow discharge time-of-flight mass spectrometry

    International Nuclear Information System (INIS)

    Reinsberg, K.-G.; Schumacher, C.; Tempez, A.; Nielsch, K.; Broekaert, J.A.C.

    2012-01-01

    In this work the depth-profile analysis of thermoelectric layers deposited on Au and Cr covered Si wafers with the aid of pulsed radiofrequency glow discharge time-of-flight mass spectrometry (pulsed RF-GD-TOFMS also called plasma profiling TOFMS (PP-TOFMS™)) is described. For thermoelectric materials the depth resolutions obtained with both PP-TOFMS and secondary ion mass spectrometry (SIMS) are shown to be well comparable and in the order of the roughness of the corresponding layers (between 20 and 3700 nm). With both methods a direct solid analysis without any preparation steps is possible. In addition, the analysis of the samples with PP-TOFMS proved to be faster by a factor of 26 compared to SIMS, as sputtering rates were found to be 80 nm s −1 and 3 nm s −1 , respectively. For the analyzed samples the results of PP-TOFMS and SIMS show that a homogeneous deposition was obtained. Quantitative results for all samples could also be obtained directly by PP-TOFMS when the stoichiometry of one sample was determined beforehand for instance by inductively coupled plasma optical emission spectrometry (ICP-OES) and scanning electron microscopy energy dispersive X-ray fluorescence spectrometry (SEM-EDX). For Bi 2 Te 3 the standard deviation for the main component concentrations within one sample then is found to be between 1.1% and 1.9% and it is 3.6% from sample to sample. For Sb 2 Te 3 the values within one sample are from 1.7% to 4.2% and from sample to sample 5.3%, respectively. - Highlights: ► Depth resolution in sub micrometer size by glow discharge mass spectrometry. ► Bi and Sb telluride layers composition with GD-TOF-MS, ICP-OES and SEM-EDX agree. ► Homogeneities of layers measured with GD-TOF-MS and SIMS agree.

  8. The back-diffusion effect of air on the discharge characteristics of atmospheric-pressure radio-frequency glow discharges using bare metal electrodes

    International Nuclear Information System (INIS)

    Sun Wenting; Liang Tianran; Wang Huabo; Li Heping; Bao Chengyu

    2007-01-01

    Radio-frequency (RF), atmospheric-pressure glow discharge (APGD) plasmas using bare metal electrodes have promising prospects in the fields of plasma-aided etching, deposition, surface treatment, disinfection, sterilization, etc. In this paper, the discharge characteristics, including the breakdown voltage and the discharge voltage for sustaining a stable and uniform α mode discharge of the RF APGD plasmas are presented. The experiments are conducted by placing the home-made planar-type plasma generator in ambient and in a vacuum chamber, respectively, with helium as the primary plasma-forming gas. When the discharge processes occur in ambient, particularly for the lower plasma-working gas flow rates, the experimental measurements show that it is the back-diffusion effect of air in atmosphere, instead of the flow rate of the gas, that results in the obvious decrease in the breakdown voltage with increasing plasma-working gas flow rate. Further studies on the discharge characteristics, e.g. the luminous structures, the concentrations and distributions of chemically active species in plasmas, with different plasma-working gases or gas mixtures need to be conducted in future work

  9. Generation of uniform low-temperature plasma in a pulsed non-self-sustained glow discharge with a large-area hollow cathode

    Energy Technology Data Exchange (ETDEWEB)

    Akhmadeev, Yu. H.; Denisov, V. V., E-mail: volodyadenisov@yandex.ru; Koval, N. N.; Kovalsky, S. S.; Lopatin, I. V.; Schanin, P. M.; Yakovlev, V. V. [Russian Academy of Sciences, Institute of High-Current Electronics, Siberian Branch (Russian Federation)

    2017-01-15

    Generation of plasma in a pulsed non-self-sustained glow discharge with a hollow cathode with an area of ≥2 m{sup 2} at gas pressures of 0.4–1 Pa was studied experimentally. At an auxiliary arc-discharge current of 100 A and a main discharge voltage of 240 V, a pulse-periodic glow discharge with a current amplitude of 370 A, pulse duration of 340 μs, and repetition rate of 1 kHz was obtained. The possibility of creating a uniform gas-discharge plasma with a density of up to 10{sup 12} cm{sup −3} and an electron temperature of 1 eV in a volume of >0.2 m{sup 3} was demonstrated. Such plasma can be efficiently used to treat material surfaces and generate pulsed ion beams with a current density of up to 15 mA/cm{sup 2}.

  10. Determination of the working conditions of the system for ion extraction from glow discharge plasma

    International Nuclear Information System (INIS)

    Murlak-Stachura, H.; Pilat, M.

    1988-01-01

    The discharge plasma was formed in discharge tube 110 cm long and 5.5 cm in diameter. An extraction probe with a bore 0.2 mm in diameter was on the tube wall about 40 cm from the anode. The probe characteristic was measured at determined pressure and intensity of discharge current. 8 refs., 3 figs. (A.S.)

  11. Studies of reaction difference between γ-ray and glow discharge on hydrogenation of unsaturated fatty acid esters

    International Nuclear Information System (INIS)

    Sakoda, Tatsuya; Nieda, Hiroshi; Kitahara, Kazuta; Ando, Kiyomi

    2000-01-01

    Hydrogenation of unsaturated fatty acid esters using an inductively coupled plasma at low pressure was performed, and electron temperature and density were measured using a double-probe in order to investigate the reaction difference between γ-ray and glow discharge on hydrogenation. In this experiment, unsaturated fatty acid esters were partly hydrogenated by the hydrogen plasma that had electron temperature of 3.5 eV, which was more efficient than γ-ray irradiation method. As a result, it was found that the plasma can effectively supply electrons that had the optimum energy for hydrogenation at the interface of fatty acids as well as excited atoms and ions. Also, the plasma generated at low pressure would be possible to convert unsaturated fatty acids into saturated fatty acids without breaking the starting monomer. (author)

  12. Canard and mixed mode oscillations in an excitable glow discharge plasma in the presence of inhomogeneous magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, Pankaj Kumar, E-mail: pankaj.shaw@saha.ac.in; Sekar Iyengar, A. N., E-mail: ansekar.iyengar@saha.ac.in [Plasma Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India); Nurujjaman, Md., E-mail: jaman-nonlinear@yahoo.co.in [Department of Physics, National Institute of Technology Sikkim, Ravangla, Sikkim 737139 (India)

    2015-12-15

    We report on the experimental observation of canard orbit and mixed mode oscillations (MMOs) in an excitable glow discharge plasma induced by an external magnetic field perturbation using a bar magnet. At a small value of magnetic field, small amplitude quasiperiodic oscillations were excited, and with the increase in the magnetic field, large amplitude oscillations were excited. Analyzing the experimental results, it seems that the magnetic field could be playing the role of noise for such nonlinear phenomena. It is observed that the noise level increases with the increase in magnetic field strength. The experimental results have also been corroborated by a numerical simulation using a FitzHugh-Nagumo like macroscopic model derived from the basic plasma equations and phenomenology, where the noise has been included to represent the internal plasma noise. This macroscopic model shows MMO in the vicinity of the canard point when an external noise is added.

  13. Excitation mechanism for nickel and argon lines emitted by radio-frequency glow discharge plasma associated with bias current introduction

    International Nuclear Information System (INIS)

    Kodama, Kenji; Wagatsuma, Kazuaki

    2004-01-01

    The introduction of d.c. bias current to an r.f. glow discharge plasma led to enhancement in the intensity of particular emission lines. In order to investigate the excitation mechanism, a large number of nickel emission lines was measured with and without the bias-current introduction. Emission intensities of nickel atomic lines were predominantly elevated by conducting bias current, especially when the emission lines have an excitation energy of approximately 5 eV. This phenomenon could be explained from the additional excitation through collisions with the introduced electrons having kinetic energies favorable for the excitation of such nickel atomic lines. However, this additional excitation mechanism was less effective for excited states of nickel ion, argon atom and argon ion, because their excitation energies were fairly high compared with the excitation energies of Ni atomic lines

  14. Adaptation of a glow discharge mass spectrometer in a glove-box for the analysis of nuclear materials

    International Nuclear Information System (INIS)

    Betti, M.; Rasmussen, G.; Hiernaut, T.; Koch, L.

    1994-01-01

    A VG9000 glow discharge mass spectrometer has been modified for the direct analysis of solid nuclear samples within a glove-box environment. Because containment is needed for the analysis of this kind of material, the glove-box encloses all parts of the instrument that come into contact with the sample, namely the ion source chamber, sample interlock and associated pumping system. External modifications eliminate outside contamination by the fitting of absolute filters on all source supplies. Internally the design of the ion source has been altered to minimize the number of operations performed inside the glove-box thereby simplifying operation and routine maintenance. These modifications retain the ion extraction and focusing properties of the instrument. The data presented show that there is no compromise in the analytical performance of the instrument when placed in the glove-box. Data representative of nuclear materials is also shown. (Author)

  15. Faraday space in a glow discharge with uniform cross section and one expanding from the cathode to the positive column

    International Nuclear Information System (INIS)

    Raizer, Y.P.; Shneider, M.N.

    1992-01-01

    A simplified asymptotic theory is used to find the distribution of the field and plasma density and to estimate the length of the Faraday dark space in a glow discharge in slab geometry and in one where the transverse cross section of the drift tube increases as a function of distance from the cathode. It is shown that the Faraday space is longer in the second case. The effects and behavior observed experimentally, including field reversal, are fully explained on the basis of the diffusive mechanism for charge transport in a very weak field without the inverse dependence of the electron mobility on the field that has been assumed in many treatments. 7 refs., 5 figs

  16. Final Report DE-FG02-00ER54583: 'Physics of Atmospheric Pressure Glow Discharges' and 'Nanoparticle Nucleation and Dynamics in Low-Pressure Plasmas'

    International Nuclear Information System (INIS)

    Kortshagen, Uwe; Heberlein, Joachim; Girshick, Steven L.

    2009-01-01

    This project was funded over two periods of three years each, with an additional year of no-cost extension. Research in the first funding period focused on the physics of uniform atmospheric pressure glow discharges, the second funding period was devoted to the study of the dynamics of nanometer-sized particles in plasmas.

  17. A Study of a Striated Positive Column after Ethanol Impurity Injection in an Air DC Glow Discharge

    Science.gov (United States)

    Berzak, Laura; Post Zwicker, Andrew

    2003-04-01

    In a glow discharge when ethanol (CH3CH2OH) was injected, a series of atypical striations formed through the positive column. When the pressure decreased as the ethanol evaporated and was evacuated by the vacuum pump, this behavior decayed away until only an anode glow or normal discharge remained. Varying interelectrode spacings and quantities of ethanol yielded similar patterns. The typical evolution as the pressure decreased consisted of a visible traveling wave traveling from the anode to the cathode followed by numerous, thin ( 1.6 mm) striations evenly spaced down the entire length of the positive column. These, shifted back toward the anode and transformed into bent striations with the tip of the 'V' pointing toward the cathode, and finally, the 'V' striations grouped into fours and took on the appearance of beats. The unusual 'V' striations may be due in part to a contraction of the column, causing the equipotential surfaces to shift from smooth convex to the observed striation shape. The conditions for this contraction effect include a nonlinearly increasing dependence of electron production rate on electron density and a bulk recombination rate higher than that at the tube walls. Visible emission spectra indicated the presence of carbon monoxide (CO), signifying that the striations are due to not only vibrational excitation of the ethanol molecule but also to decomposition and subsequent excitation of the decomposition products as well. One possible mechanism of decomposition is the formation of a radical cation from the ethanol molecule and the ensuing loss of a proton to yield formaldehyde; this then would follow an analogous decomposition to produce carbon monoxide. Thus, there may exist additional charged species which can then contribute to the unique observations. Further analysis, if possible, will include higher temporal resolution spectroscopy and a detailed model of the positive column under these specific conditions.

  18. Enhancement of Osteoblastic-Like Cell Activity by Glow Discharge Plasma Surface Modified Hydroxyapatite/β-Tricalcium Phosphate Bone Substitute

    Directory of Open Access Journals (Sweden)

    Eisner Salamanca

    2017-11-01

    Full Text Available Glow discharge plasma (GDP treatments of biomaterials, such as hydroxyapatite/β-tricalcium phosphate (HA/β-TCP composites, produce surfaces with fewer contaminants and may facilitate cell attachment and enhance bone regeneration. Thus, in this study we used argon glow discharge plasma (Ar-GDP treatments to modify HA/β-TCP particle surfaces and investigated the physical and chemical properties of the resulting particles (HA/β-TCP + Ar-GDP. The HA/β-TCP particles were treated with GDP for 15 min in argon gas at room temperature under the following conditions: power: 80 W; frequency: 13.56 MHz; pressure: 100 mTorr. Scanning electron microscope (SEM observations showed similar rough surfaces of HA/β-TCP + Ar-GDP HA/β-TCP particles, and energy dispersive spectrometry analyses showed that HA/β-TCP surfaces had more contaminants than HA/β-TCP + Ar-GDP surfaces. Ca/P mole ratios in HA/β-TCP and HA/β-TCP + Ar-GDP were 1.34 and 1.58, respectively. Both biomaterials presented maximal intensities of X-ray diffraction patterns at 27° with 600 a.u. At 25° and 40°, HA/β-TCP + Ar-GDP and HA/β-TCP particles had peaks of 200 a.u., which are similar to XRD intensities of human bone. In subsequent comparisons, MG-63 cell viability and differentiation into osteoblast-like cells were assessed on HA/β-TCP and HA/β-TCP + Ar-GDP surfaces, and Ar-GDP treatments led to improved cell growth and alkaline phosphatase activities. The present data indicate that GDP surface treatment modified HA/β-TCP surfaces by eliminating contaminants, and the resulting graft material enhanced bone regeneration.

  19. Atmospheric-pressure solution-cathode glow discharge: A versatile ion source for atomic and molecular mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Andrew J. [Department of Chemistry, Indiana University, Bloomington, IN, 47405 (United States); Williams, Kelsey L. [Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44242 (United States); Hieftje, Gary M. [Department of Chemistry, Indiana University, Bloomington, IN, 47405 (United States); Shelley, Jacob T., E-mail: shellj@rpi.edu [Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44242 (United States); Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY, 12180 (United States)

    2017-01-15

    An atmospheric-pressure solution-cathode glow discharge (SCGD) has been evaluated as an ion source for atomic, molecular, and ambient desorption/ionization mass spectrometry. The SCGD consists of a direct-current plasma, supported in the ambient air in the absence of gas flows, and sustained upon the surface of a flowing liquid cathode. Analytes introduced in the flowing liquid, as an ambient gas, or as a solid held near the plasma are vaporized and ionized by interactions within or near the discharge. Introduction of acidic solutions containing metal salts produced bare elemental ions as well as H{sub 2}O, OH{sup −} and NO{sub 3}{sup −} adducts. Detection limits for these elemental species ranged from 0.1 to 4 ppb, working curves spanned more than 4 orders of linear dynamic range, and precision varied between 5 and 16% relative standard deviation. Small organic molecules were also efficiently ionized from solution, and both the intact molecular ion and fragments were observed in the resulting SCGD mass spectra. Fragmentation of molecular species was found to be tunable; high discharge currents led to harder ionization, while low discharge currents produced stronger molecular-ion signals. Ambient gases and solids, desorbed by the plasma from a glass probe, were also readily ionized by the SCGD. Indeed, strong analyte signals were obtained from solid samples placed at least 2 cm from the plasma. These findings indicate that the SCGD might be useful also for ambient desorption/ionization mass spectrometry. Combined with earlier results that showed the SCGD is useful for ionization of labile biomolecules, the results here indicate that the SCGD is a highly versatile ion source capable of providing both elemental and molecular mass-spectral information. - Highlights: • Solution-cathode glow discharge used as an ionization source for mass spectrometry. • SCGD-MS can provide atomic as well as intact molecular mass spectra. • Atomic limits of detection range

  20. Characterization of argon direct-current glow discharge with a longitudinal electric field applied at ambient air

    Science.gov (United States)

    Jiang, Weiman; Tang, Jie; Wang, Yishan; Zhao, Wei; Duan, Yixiang

    2014-09-01

    A direct-current-driven plasma jet is developed by applying a longitudinal electric field on the flowing argon at ambient air. This plasma shows a torch shape with its cross-section increased from the anode to the cathode. Comparison with its counterparts indicates that the gas flow plays a key role in variation of the plasma structure and contributes much to enlarging the plasma volume. It is also found that the circular hollow metal base promotes generation of plasma with a high-power volume density in a limited space. The optical emission spectroscopy (OES) diagnosis indicates that the plasma comprises many reactive species, such as OH, O, excited N2, and Ar metastables. Examination of the rotational and vibrational temperature indicates that the plasma is under nonequilibrium condition and the excited species OH(A 2Σ+), O(5P), and N2(C 3Πu) are partly generated by energy transfer from argon metastables. The spatially resolved OES of plasma reveals that the negative glow, Faraday dark space, and positive column are distributed across the gas gap. The absence of the anode glow is attributed to the fact that many electrons in the vicinity of the anode follow ions into the positive column due to the ambipolar diffusion in the flowing gas.

  1. A diffusive atmospheric pressure glow discharge in a coaxial pin-to-ring gap with a transverse magnetic field

    Directory of Open Access Journals (Sweden)

    YongSheng Wang

    2017-09-01

    Full Text Available Atmospheric pressure glow discharge (APGD has been widely used in the industrial field. The industrial applications are based on achieving stable and diffusive APGD in a relatively large space. The existing sources only achieved stable and diffusive APGD between a short inter-electrode distance within 5 millimeters. In this paper, the effect of a transverse stationary magnetic field on the diffusion of filamentary APGD was studied in a pin-to-ring coaxial gap. The APGD was driven by a high-voltage resonant power supply, and the stationary magnetic field was supplied by a permanent magnet. The stable and diffusive APGD was achieved in the circular area, which diameter was 20 millimeters. The experimental results revealed that more collision ionization occurred and the plasma was distributed diffusively in the discharge gap by applying the external transverse magnetic field. Besides, it is likely to obtain more stable and diffusive APGD in the coaxial pin-to-ring discharge gap when adjusting the input voltage, transverse magnetic flux density and resonant frequency of the power supply.

  2. Absorption spectroscopic studies of carbon dioxide conversion in a low pressure glow discharge using tunable infrared diode lasers

    International Nuclear Information System (INIS)

    Hempel, F; Roepcke, J; Miethke, F; Wagner, H-E

    2002-01-01

    The time and spatial dependence of the chemical conversion of CO 2 to CO were studied in a closed glow discharge reactor (p = 50 Pa, I = 2-30 mA) consisting of a small plasma zone and an extended stationary afterglow. Tunable infrared diode laser absorption spectroscopy has been applied to determine the absolute ground state concentrations of CO and CO 2 . After a certain discharge time an equilibrium of the concentrations of both species could be observed. The spatial dependence of the equilibrium CO concentration in the afterglow was found to be varying less than 10%. The feed gas was converted to CO more predominantly between 43% and 60% with increasing discharge current, forming so-called quasi-equilibrium states of the stable reaction products. The formation time of the stable gas composition also decreased with the current. For currents higher than 10 mA the conversion rate of CO 2 to CO was estimated to be 1.2x10 13 molecules J -1 . Based on the experimental results, a plasma chemical modelling has been established

  3. Influence of duration and rate of pulse rise of the applied voltage on ozone concentration in the barrier glow discharge

    International Nuclear Information System (INIS)

    Krasnyj, V.V.; Klosovski, A.V.; Knysh, A.S.; Shvets, O.M.; Taran, V.S.; Tereshin, V.I.

    2005-01-01

    The barrier glow discharge between two planar electrodes, covered with dielectric, is studied under high-voltage pulsed power supply. Wide applications of such type of discharges, in particular, for ozone production, stimulated a number of investigations in this direction. In this work we investigated the dependence of ozone concentration on the duration and the rate of pulse rise of the applied voltage. The thyristor converter circuit with the shortening of input pulses on the base of the saturable throttle was used for the realization of this task. The output pulses with amplitude up to 15 kV, repetition frequency of 1 kHz, pulse duration of 0.3 μs (or 7 μs) and the rate of pulse rise of 0.1 μs were generated with this scheme. Measurements of the ozone concentration produced in the air mixture have shown that its value increased by factor two with variation of the rate of pulse rise from 0.5 μs to 0.1 μs (for pulse duration of 7 μs). The dependence of the ozone concentration on the variation of air mixture pressure in the discharge gap of reactor was investigated also. It was shown proportional increase of the output concentration of ozone with increasing the pressure value. Spectroscopic measurements carried out in the ultraviolet spectrum made it possible to analyze changing the concentration of ozone and nitric components. (author)

  4. Contrasting characteristics of sub-microsecond pulsed atmospheric air and atmospheric pressure helium-oxygen glow discharges

    International Nuclear Information System (INIS)

    Walsh, J L; Liu, D X; Iza, F; Kong, M G; Rong, M Z

    2010-01-01

    Glow discharges in air are often considered to be the ultimate low-temperature atmospheric pressure plasmas for numerous chamber-free applications. This is due to the ubiquitous presence of air and the perceived abundance of reactive oxygen and nitrogen species in air plasmas. In this paper, sub-microsecond pulsed atmospheric air plasmas are shown to produce a low concentration of excited oxygen atoms but an abundance of excited nitrogen species, UV photons and ozone molecules. This contrasts sharply with the efficient production of excited oxygen atoms in comparable helium-oxygen discharges. Relevant reaction chemistry analysed with a global model suggests that collisional excitation of O 2 by helium metastables is significantly more efficient than electron dissociative excitation of O 2 , electron excitation of O and ion-ion recombination. These results suggest different practical uses of the two oxygen-containing atmospheric discharges, with air plasmas being well suited for nitrogen and UV based chemistry and He-O 2 plasmas for excited atomic oxygen based chemistry. (fast track communication)

  5. FAST TRACK COMMUNICATION: Contrasting characteristics of sub-microsecond pulsed atmospheric air and atmospheric pressure helium-oxygen glow discharges

    Science.gov (United States)

    Walsh, J. L.; Liu, D. X.; Iza, F.; Rong, M. Z.; Kong, M. G.

    2010-01-01

    Glow discharges in air are often considered to be the ultimate low-temperature atmospheric pressure plasmas for numerous chamber-free applications. This is due to the ubiquitous presence of air and the perceived abundance of reactive oxygen and nitrogen species in air plasmas. In this paper, sub-microsecond pulsed atmospheric air plasmas are shown to produce a low concentration of excited oxygen atoms but an abundance of excited nitrogen species, UV photons and ozone molecules. This contrasts sharply with the efficient production of excited oxygen atoms in comparable helium-oxygen discharges. Relevant reaction chemistry analysed with a global model suggests that collisional excitation of O2 by helium metastables is significantly more efficient than electron dissociative excitation of O2, electron excitation of O and ion-ion recombination. These results suggest different practical uses of the two oxygen-containing atmospheric discharges, with air plasmas being well suited for nitrogen and UV based chemistry and He-O2 plasmas for excited atomic oxygen based chemistry.

  6. Doppler spectroscopy of hydrogen Balmer lines in a hollow cathode glow discharge in ammonia and argon-ammonia mixture

    International Nuclear Information System (INIS)

    Sisovic, N. M.; Konjevic, N.

    2008-01-01

    The results of Doppler spectroscopy of hydrogen Balmer lines from a stainless steel (SS) and copper (Cu) hollow cathode (HC) glow discharge in ammonia and argon-ammonia mixture are reported. The experimental profiles in ammonia discharge are fitted well by superposing three Gaussian profiles. The half widths, in energy units, of narrow and medium Gaussians are in the ranges 0.3-0.4 eV and 3-4 eV, respectively, for both hollow cathodes what is expected on the basis of earlier electron beam→NH 3 experiments. The half widths of the largest Gaussian in ammonia are 46 and 55 eV for SS and Cu HC, respectively. In argon-ammonia discharge, three Gaussians are also required to fit experimental profiles. While half widths of narrow and medium Gaussians are similar to those in ammonia, the half widths of the largest Gaussians are 35 and 42 eV for SS and Cu HC, respectively. The half widths of the largest Gaussians in ammonia and in argon-ammonia mixture indicate the presence of excessive Doppler broadening.

  7. Self-organized criticality: An interplay between stable and turbulent regimes of multiple anodic double layers in glow discharge plasma

    Science.gov (United States)

    Alex, Prince; Carreras, Benjamin Andres; Arumugam, Saravanan; Sinha, Suraj Kumar

    2018-05-01

    The role of self-organized criticality (SOC) in the transformation of multiple anodic double layers (MADLs) from the stable to turbulent regime has been investigated experimentally as the system approaches towards critical behavior. The experiment was performed in a modified glow discharge plasma setup, and the initial stable state of MADL comprising three concentric perceptible layers was produced when the drift velocity of electrons towards the anode exceeds the electron thermal velocity (νd ≥ 1.3νte). The macroscopic arrangement of both positive and negative charges in opposite layers of MADL is attributed to the self-organization scenario. Beyond νd ≥ 3νte, MADL begins to collapse and approaches critical and supercritical states through layer reduction which continue till the last remaining layer of the double layer is transformed into a highly unstable radiant anode glow. The avalanche resulting from the collapse of MADL leads to the rise of turbulence in the system. Long-range correlations, a key signature of SOC, have been explored in the turbulent floating potential fluctuations using the rescaled-range analysis technique. The result shows that the existence of the self-similarity regime with self-similarity parameter H varies between 0.55 and 0.91 for time lags longer than the decorrelation time. The power law tail in the rank function, slowly decaying tail of the autocorrelation function, and 1/f behavior of the power spectra of the fluctuations are consistent with the fact that SOC plays a conclusive role in the transformation of MADL from the stable to turbulent regime. Since the existence of SOC gives a measure of complexity in the system, the result provides the condition under which complexity arises in cold plasma.

  8. Multiple solutions in the theory of direct current glow discharges: Effect of plasma chemistry and nonlocality, different plasma-producing gases, and 3D modelling

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, P. G. C.; Benilov, M. S. [Departamento de Física, CCCEE, Universidade da Madeira, Largo do Município, 9000 Funchal (Portugal)

    2013-10-15

    The work is aimed at advancing the multiple steady-state solutions that have been found recently in the theory of direct current (DC) glow discharges. It is shown that an account of detailed plasma chemistry and non-locality of electron transport and kinetic coefficients results in an increase of the number of multiple solutions but does not change their pattern. Multiple solutions are shown to exist for discharges in argon and helium provided that discharge pressure is high enough. This result indicates that self-organization in DC glow microdischarges can be observed not only in xenon, which has been the case until recently, but also in other plasma-producing gases; a conclusion that has been confirmed by recent experiments. Existence of secondary bifurcations can explain why patterns of spots grouped in concentric rings, observed in the experiment, possess in many cases higher number of spots in outer rings than in inner ones.

  9. Modification of hydrophobic acrylic intraocular lens with poly(ethylene glycol) by atmospheric pressure glow discharge: A facile approach

    International Nuclear Information System (INIS)

    Lin Lin; Wang Yao; Huang Xiaodan; Xu Zhikang; Yao Ke

    2010-01-01

    To improve the anterior surface biocompatibility of hydrophobic acrylic intraocular lens (IOL) in a convenient and continuous way, poly(ethylene glycol)s (PEGs) were immobilized by atmospheric pressure glow discharge (APGD) treatment using argon as the discharge gas. The hydrophilicity and chemical changes on the IOL surface were characterized by static water contact angle and X-ray photoelectron spectroscopy to confirm the covalent binding of PEG. The morphology of the IOL surface was observed under field emission scanning electron microscopy and atomic force microscopy. The surface biocompatibility was evaluated by adhesion experiments with platelets, macrophages, and lens epithelial cells (LECs) in vitro. The results revealed that the anterior surface of the PEG-grafted IOL displayed significantly and permanently improved hydrophilicity. Cell repellency was observed, especially in the PEG-modified IOL group, which resisted the attachment of platelets, macrophages and LECs. Moreover, the spread and growth of cells were suppressed, which may be attributed to the steric stabilization force and chain mobility effect of the modified PEG. All of these results indicated that hydrophobic acrylic IOLs can be hydrophilic modified by PEG through APGD treatment in a convenient and continuous manner which will provide advantages for further industrial applications.

  10. Electron energy distribution function in the positive column of a neon glow discharge using the black wall approximation

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hawat, Sh; Naddaf, M [Physics Department, Atomic Energy Commission, PO Box 6091, Damascus (Syrian Arab Republic)

    2005-04-21

    The electron energy distribution function (EEDF) was determined from the second derivative of the I-V Langmuir probe characteristics and, thereafter, theoretically calculated by solving the plasma kinetic equation, using the black wall (BW) approximation, in the positive column of a neon glow discharge. The pressure has been varied from 0.5 to 4 Torr and the current from 10 to 30 mA. The measured electron temperature, density and electric field strength were used as input data for solving the kinetic equation. Comparisons were made between the EEDFs obtained from experiment, the BW approach, the Maxwellian distribution and the Rutcher solution of the kinetic equation in the elastic energy range. The best conditions for the BW approach are found to be under the discharge conditions: current density j{sub d} = 4.45 mA cm{sup -2} and normalized electric field strength E/p = 1.88 V cm{sup -1} Torr{sup -1}.

  11. Positive-column plasma studied by fast-flow glow discharge mass spectrometry: Could it be a 'Rydberg gas?'

    International Nuclear Information System (INIS)

    Mason, Rod S.; Miller, Pat D.; Mortimer, Ifor; Mitchell, David J.; Dash, Neil A.

    2003-01-01

    Ions created from the fast-flowing positive column plasma of a glow discharge were monitored using a high voltage magnetic sector mass spectrometer. Since the field gradient and sheath potentials created by the plasma inside the source opposed cation transfer, it is inferred that the ions detected were the field-ionized Rydberg species. This is supported by the mass spectral changes which occurred when a negative bias was applied to the sampling aperture and by the contrasting behavior when attached to a quadrupole analyzer. Reaction with H 2 (titrated into the flowing plasma) quenched not only the ionization of discharge gas Rydberg atoms but also the passage of electric current through the plasma, without significant changes to the field and sheath potentials. Few 'free' ions were present and the lifetimes of the Rydberg atoms detected were much longer than seen in lower pressure experiments, indicating additional stabilization in the plasma environment. The observations support the model of the flowing plasma, given previously [R. S. Mason, P. D. Miller, and I. P. Mortimer, Phys. Rev. E 55, 7462 (1997)] as mainly a neutral Rydberg atom gas, rather than a conventional ion-electron plasma

  12. Emission characteristics of laser ablation-hollow cathode glow discharge spectral source

    Directory of Open Access Journals (Sweden)

    Karatodorov Stefan

    2014-11-01

    Full Text Available The emission characteristics of a scheme combining laser ablation as sample introduction source and hollow cathode discharge as excitation source are presented. The spatial separation of the sample material introduction by laser ablation and hollow cathode excitation is achieved by optimizing the gas pressure and the sample-cathode gap length. At these conditions the discharge current is maximized to enhance the analytical lines intensity.

  13. Depth-profile analysis of thermoelectric layers on Si wafers by pulsed r.f. glow discharge time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Reinsberg, K.-G. [Institute for Inorganic and Applied Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, D-20146 Hamburg (Germany); Schumacher, C. [Institute for Applied Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg (Germany); Tempez, A. [HORIBA Jobin Yvon, 16-18 rue du Canal, F-91160 Longjumeau (France); Nielsch, K. [Institute for Applied Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg (Germany); Broekaert, J.A.C., E-mail: jose.broekaert@chemie.uni-hamburg.de [Institute for Inorganic and Applied Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, D-20146 Hamburg (Germany)

    2012-10-15

    In this work the depth-profile analysis of thermoelectric layers deposited on Au and Cr covered Si wafers with the aid of pulsed radiofrequency glow discharge time-of-flight mass spectrometry (pulsed RF-GD-TOFMS also called plasma profiling TOFMS (PP-TOFMS Trade-Mark-Sign )) is described. For thermoelectric materials the depth resolutions obtained with both PP-TOFMS and secondary ion mass spectrometry (SIMS) are shown to be well comparable and in the order of the roughness of the corresponding layers (between 20 and 3700 nm). With both methods a direct solid analysis without any preparation steps is possible. In addition, the analysis of the samples with PP-TOFMS proved to be faster by a factor of 26 compared to SIMS, as sputtering rates were found to be 80 nm s{sup -1} and 3 nm s{sup -1}, respectively. For the analyzed samples the results of PP-TOFMS and SIMS show that a homogeneous deposition was obtained. Quantitative results for all samples could also be obtained directly by PP-TOFMS when the stoichiometry of one sample was determined beforehand for instance by inductively coupled plasma optical emission spectrometry (ICP-OES) and scanning electron microscopy energy dispersive X-ray fluorescence spectrometry (SEM-EDX). For Bi{sub 2}Te{sub 3} the standard deviation for the main component concentrations within one sample then is found to be between 1.1% and 1.9% and it is 3.6% from sample to sample. For Sb{sub 2}Te{sub 3} the values within one sample are from 1.7% to 4.2% and from sample to sample 5.3%, respectively. - Highlights: Black-Right-Pointing-Pointer Depth resolution in sub micrometer size by glow discharge mass spectrometry. Black-Right-Pointing-Pointer Bi and Sb telluride layers composition with GD-TOF-MS, ICP-OES and SEM-EDX agree. Black-Right-Pointing-Pointer Homogeneities of layers measured with GD-TOF-MS and SIMS agree.

  14. Glow discharge preparation and electrooptical characterisation of amorphous silicon alloys for solar cells. Preparacion por descarga luminiscente y caracterizacion electrooptica de aleaciones de silicio amorfo para celulas solares

    Energy Technology Data Exchange (ETDEWEB)

    Carabe, J

    1990-11-01

    A study is presented, focused on the preparation and characterisation of hydrogenated amorphous silicon alloy thin films for their application as p type window layers in pin silicon solar cells. The preparation technique used was radio frequency glow discharge. The samples were characterised optically (visible, near infrared and infrared absorption spectrophotometry) and electrically (dark and photoconductivities at ambient temperature and as functions of temperature). The influence of each of the preparation parameters on film properties has been systematically studied. The results have been analysed according to the existing models. Chapter 1 is an introduction to the material in question and its photovoltaic applications. Chapter 2 describes the experimental procedure used. Capter 3 shows and discusses the most relevant results obtained in the study of intrinsic amorphous silicon, p type amorphous silicon and p type amorphous silicon carbide window layers, with special emphasis on the influence of the use of an alternative dopant gas: boron trifluoride. Finally, chapter 4 summarises the most relevant conclusions drawn from this research work. (Author)

  15. Glow Discharge Emission Spectrometry (GDOES): Theoretical Introduction, General Aspects, and its Applications within the Framework of the Technofusion Programs; Glow Discharge Emission Spectrometry (GDOES): Introduccion Teorica, Aspectos Generales y Aplicabilidad en el Marco del Programa Technofusion

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Rojo, A. B.; Gonzalez, M.; Tabares, F. L.

    2013-02-01

    The demand by material research groups for the direct composition analysis of solids is increasing as a solution to the time-consuming problems and errors inherent to classical chemical analysis, where the attack and solubilisation of the starting material is mandatory, often producing the introduction of impurities and component loss of the initial matrix. From the existing solid analysis techniques the present work is focused on the Glow Discharge Emission Spectrometry (GDOES), a fast, simply-executed technique, for which quantitative, high resolution depth profile determination of any element in the periodic table can be performed with a high sensibility and detection limit. The theoretical concepts, the required instrumentation and the basic analytic applications are revised, giving especial attention to the issues related to the analysis of materials for fusion applications. Finally, a comparative study with a more advanced spectroscopic technique (Secondary Ion Mass Spectrometry (SIMS)) is performed and the concomitance of both techniques to correct limitations such as the spatial resolution and the quantification of the analysis, important factors that are required in the chemical analysis of the complex materials used in Fusion, is addressed. (Author) 41 refs.

  16. Comparison of dielectric barrier discharge, atmospheric pressure radiofrequency-driven glow discharge and direct analysis in real time sources for ambient mass spectrometry of acetaminophen

    Energy Technology Data Exchange (ETDEWEB)

    Kratzer, Jan [Institute for National Measurement Standards, National Research Council of Canada, 1200 Montreal Road, Ottawa, Ontario, K1A 0R6 (Canada); Institute of Analytical Chemistry of the ASCR, v.v.i., Veveri 97, CZ-602 00 Brno (Czech Republic); Mester, Zoltan [Institute for National Measurement Standards, National Research Council of Canada, 1200 Montreal Road, Ottawa, Ontario, K1A 0R6 (Canada); Sturgeon, Ralph E., E-mail: Ralph.Sturgeon@nrc-cnrc.gc.ca [Institute for National Measurement Standards, National Research Council of Canada, 1200 Montreal Road, Ottawa, Ontario, K1A 0R6 (Canada)

    2011-08-15

    Three plasma-based ambient pressure ion sources were investigated; laboratory constructed dielectric barrier and rf glow discharges, as well as a commercial corona discharge (DART source). All were used to desorb and ionize a model analyte, providing sampling techniques for ambient mass spectrometry (MS). Experimental parameters were optimized to achive highest signal for acetaminophen as the analyte. Insight into the mechanisms of analyte desorption and ionization was obtained by means of emission spectrometry and ion current measurements. Desorption and ionization mechanisms for this analyte appear to be identical for all three plasma sources. Emission spectra differ only in the intensities of various lines and bands. Desorption of solid analyte requires transfer of thermal energy from the plasma source to sample surface, in the absence of which complete loss of MS response occurs. For acetaminophen, helium was the best plasma gas, providing 100- to 1000-fold higher analyte response than with argon or nitrogen. The same trend was also evident with background ions (protonated water clusters). MS analyte signal intensity correlates with the ion density (expressed as ion current) in the plasma plume and with emission intensity from excited state species in the plasma. These observations support an ionization process which occurs via proton transfer from protonated water clusters to analyte molecules.

  17. Study of a new direct current atmospheric pressure glow discharge in helium

    Energy Technology Data Exchange (ETDEWEB)

    Gielniak, B. [University of Hamburg, Institute for Inorganic and Applied Chemistry, Martin-Luther-King-Platz 6, 20146 Hamburg (Germany); Fiedler, T. [Johannes Gutenberg-University Mainz, Institute for Inorganic and Analytical Chemistry, Duesbergweg 10-14, 55128 Mainz (Germany); Broekaert, J.A.C., E-mail: jose.broekaert@chemie.uni-hamburg.de [University of Hamburg, Institute for Inorganic and Applied Chemistry, Martin-Luther-King-Platz 6, 20146 Hamburg (Germany)

    2011-01-15

    In this study a new DC-APGD operated in He was developed and characterized. The discharge is operated at 0.9 kV and about 25-35 mA and at a gas flow of 100 ml/min. The source was spectroscopically studied and parameters such as the rotational temperature (T{sub rot}), the excitation temperature (T{sub exc}), the ionization temperature (T{sub ion}) and the electron number density (n{sub e}) were determined. The current-voltage characteristic of the source was studied as well. At optimized conditions the discharge operates in the normal region of the current-voltage characteristic. Rotational and excitation temperatures determined with the use of OH band and Fe I lines as thermometric species were of the order of about 900-1200 and 4500-5500 K, respectively. This indicates that despite of the atmospheric pressure, the discharge is not in LTE. Spatially resolved temperature measurements were performed with axial as well as radial resolution and showed relatively flat profiles. Axially resolved emission intensity profiles for several species such as H, N{sub 2}, N{sub 2}{sup +}, OH, He and Hg were determined. It also was found that H{sub 2} introduced into the He by electrolysis of acid solutions such as in ECHG considerably increases the spectroscopically measured gas temperatures but decreases the analyte line intensities, as shown for Hg.

  18. Study of a new direct current atmospheric pressure glow discharge in helium

    International Nuclear Information System (INIS)

    Gielniak, B.; Fiedler, T.; Broekaert, J.A.C.

    2011-01-01

    In this study a new DC-APGD operated in He was developed and characterized. The discharge is operated at 0.9 kV and about 25-35 mA and at a gas flow of 100 ml/min. The source was spectroscopically studied and parameters such as the rotational temperature (T rot ), the excitation temperature (T exc ), the ionization temperature (T ion ) and the electron number density (n e ) were determined. The current-voltage characteristic of the source was studied as well. At optimized conditions the discharge operates in the normal region of the current-voltage characteristic. Rotational and excitation temperatures determined with the use of OH band and Fe I lines as thermometric species were of the order of about 900-1200 and 4500-5500 K, respectively. This indicates that despite of the atmospheric pressure, the discharge is not in LTE. Spatially resolved temperature measurements were performed with axial as well as radial resolution and showed relatively flat profiles. Axially resolved emission intensity profiles for several species such as H, N 2 , N 2 + , OH, He and Hg were determined. It also was found that H 2 introduced into the He by electrolysis of acid solutions such as in ECHG considerably increases the spectroscopically measured gas temperatures but decreases the analyte line intensities, as shown for Hg.

  19. Fluorine and boron co-doped diamond-like carbon films deposited by pulsed glow discharge plasma immersion ion processing

    CERN Document Server

    He, X M; Peters, A M; Taylor, B; Nastasi, M

    2002-01-01

    Fluorine (F) and boron (B) co-doped diamond-like carbon (FB-DLC) films were prepared on different substrates by the plasma immersion ion processing (PIIP) technique. A pulse glow discharge plasma was used for the PIIP deposition and was produced at a pressure of 1.33 Pa from acetylene (C sub 2 H sub 2), diborane (B sub 2 H sub 6), and hexafluoroethane (C sub 2 F sub 6) gas. Films of FB-DLC were deposited with different chemical compositions by varying the flow ratios of the C sub 2 H sub 2 , B sub 2 H sub 6 , and C sub 2 F sub 6 source gases. The incorporation of B sub 2 H sub 6 and C sub 2 F sub 6 into PIIP deposited DLC resulted in the formation of F-C and B-C hybridized bonding structures. The levels of the F and B concentrations effected the chemical bonding and the physical properties as was evident from the changes observed in density, hardness, stress, friction coefficient, and contact angle of water on films. Compared to B-doped or F-doped DLC films, the F and B co-doping of DLC during PIIP deposition...

  20. Glow Discharge Emission Spectrometry (GDOES): Theoretical Introduction, General Aspects, and its Applications within the Framework of the Technofusion Programs

    International Nuclear Information System (INIS)

    Martin-Rojo, A. B.; Gonzalez, M.; Tabares, F. L.

    2013-01-01

    The demand by material research groups for the direct composition analysis of solids is increasing as a solution to the time-consuming problems and errors inherent to classical chemical analysis, where the attack and solubilisation of the starting material is mandatory, often producing the introduction of impurities and component loss of the initial matrix. From the existing solid analysis techniques the present work is focused on the Glow Discharge Emission Spectrometry (GDOES), a fast, simply-executed technique, for which quantitative, high resolution depth profile determination of any element in the periodic table can be performed with a high sensibility and detection limit. The theoretical concepts, the required instrumentation and the basic analytic applications are revised, giving especial attention to the issues related to the analysis of materials for fusion applications. Finally, a comparative study with a more advanced spectroscopic technique (Secondary Ion Mass Spectrometry (SIMS)) is performed and the concomitance of both techniques to correct limitations such as the spatial resolution and the quantification of the analysis, important factors that are required in the chemical analysis of the complex materials used in Fusion, is addressed. (Author) 41 refs.

  1. Comprehensive Evaluation of the Properties of Nanocrystalline Diamond Coatings Grown Using CVD with E/H Field Glow Discharge Stabilization

    Directory of Open Access Journals (Sweden)

    Iu. Nasieka

    2015-01-01

    Full Text Available The nanocrystalline diamond films (coatings were prepared using the plasma enhanced chemical vapor deposition (PECVD technique. In this method, direct current (DC glow discharge in the crossed E/H fields was used to activate the gas phase. The diamond coatings were deposited from the working gas mixture CH4/H2 with addition of nitrogen in various concentrations. It was ascertained that addition of N2 to the working gas mixture leads to reduction in the sizes of diamond grains as well as to the substantial decrease in the resistivity of the studied films. The electrophysical data are in good agreement with the changes induced by varying the N2 content in the Raman scattering spectra. The increase in the N2 concentration causes significant lowering of the crystalline diamond related peak and increase in the intensity of the peaks related to the sp2-bonded carbon. These changes in the spectra indicate significant disordering of the structure of prepared films and its uniformity in the nanodiamond film volume. With the great possibility, it is associated with a decrease in the sizes of diamond crystalline grains and tendency of NCD film to amorphization.

  2. Degradation of phenol and Cr (VI) wastewater with contact glow discharge electrolysis method and the addition of Fe2+

    Science.gov (United States)

    Kurniawan, Raden Ridzki Aditya; Saksono, Nelson

    2017-11-01

    Phenol and Cr (VI) are an organic waste and dangerous heavy metals which generated from a wide variety of industrial processes such as textiles, paints, dyes, and others. For that reason, we need effective waste treatment technologies, one of them is Contact Glow Discharge Electrolysis (CGDE). This method produce reactive species such as radical hidroxyl so as to be able to degradate phenol and Cr(VI) wastewater effectively. This research aims to obtain the effect of Fe 2+ and air bubbles in degradation of phenol and Cr (VI) waste simultaneously. Waste degradation is measured its absorbance with UV-Vis spectrophotometer. In the conditions of 600 Volt voltage, Na2SO4 0.02 M, anode depth of 1.5 cm, the addition of Fe2+ 40 ppm and the addition of air bubbles for 30 minutes was obtained a percentage degradation of phenol 99.47%, Cr (VI) 76.75% and specific energy of 344.473 kJ / mmol.

  3. Shock compression of glow discharge polymer (GDP): density functional theory (DFT) simulations and experiments on Sandia's Z machine

    Science.gov (United States)

    Cochrane, Kyle R.; Ao, T.; Lemke, R. W.; Hamel, S.; Schoff, M. E.; Blue, B. E.; Herrmann, M. C.; Mattsson, T. R.

    2014-03-01

    Glow discharge polymer (GDP) is used extensively as capsule/ablation material in inertial confinement fusion (ICF) capsules. Accurate knowledge of the equation of state (EOS) under shock and release is particularly important for high-fidelity design, analysis, and optimization of ICF experiments since the capsule material is subject to several converging shocks as well as release towards the cryogenic fuel. We performed Density Functional Theory (DFT) based quantum molecular dynamics (QMD) simulations, to gain knowledge of the behavior of GDP - for example regarding the role of chemical dissociation during shock compression, we find that the dissociation regime along the Hugoniot extends from 50 GPa to 250 GPa. The shock pressures calculated from DFT are compared experimental data taken at Sandia's Z-machine. The GDP samples were grown in a planar geometry to improve the sample quality and maintained in a nitrogen atmosphere following manufacturing, thus allowing for a direct comparison to the DFT/QMD simulations. Sandia National Laboratories is a multi program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's NNSA under contract DE-AC04-94AL85000.

  4. Shock compression of glow discharge polymer (GDP): density functional theory (DFT) simulations and experiments on Sandia's Z-machine

    Science.gov (United States)

    Mattsson, Thomas R.; Cochrane, K. R.; Ao, T.; Lemke, R. W.; Flicker, D. G.; Schoff, M. E.; Blue, B. E.; Hamel, S.; Herrmann, M. C.

    2015-11-01

    Glow discharge polymer (GDP) is used extensively as capsule/ablation material in inertial confinement fusion (ICF) capsules. Accurate knowledge of the equation of state (EOS) under shock and release is particularly important for high-fidelity design, analysis, and optimization of ICF experiments since the capsule material is subject to several converging shocks as well as release towards the cryogenic fuel. We performed Density Functional Theory (DFT) based quantum molecular dynamics (QMD) simulations, to gain knowledge of the behavior of GDP - including the effect of changes in chemical composition. The shock pressures calculated from DFT are compared experimental data taken on magnetically launched flyer plate impact experiments on at Sandia's Z-machine. Large GDP samples were grown in a planar geometry to improve the sample quality and maintained in a nitrogen atmosphere following manufacturing, thus allowing for a direct comparison to the DFT/QMD simulations. Sandia National Laboratories is a multi program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's NNSA under contract DE-AC04-94AL85000.

  5. Radiative lifetime and collisional quenching of carbon monochloride (A 2Δ) in an alternating current glow discharge

    International Nuclear Information System (INIS)

    Gottscho, R.A.; Burton, R.H.; Davis, G.P.

    1982-01-01

    Glow discharges are widely employed in semiconductor processing but are relatively poorly understood owing to, in part, a lack of reliable, quantitative diagnostics. Laser-induced fluorescence promises to be a useful in situ, nonintrusive probe for species concentrations and gas-phase temperatures, but requires the determination of fluoresence yields (i.e., radiative vs nonradiative decay rates) as a function of the plasma state and molecular rotational quantum number. In this work, carbon tetrachloride plasmas, which are used in the dry etching of such materials as Al, Si, GaAs, and InP, are examined using the laser-induced fluorescence technique. The quantum yield phi of CCl A 2 Δ→X 2 Pi fluorescence is determined as a function of pressure, flow-rate, power, electrode temperature, and feedstock composition. Total pressure and addition of Cl 2 to the feedstock are found to be most important in reducing the quantum yield; other plasma parameters and addition of O 2 , He, Ar, or N 2 are found to be of secondary importance. The radiative lifetime of carbon monochloride CCl, A 2 Δ (v = 0) is found to be 105 +- 3 ns and to be independent of rotational quantum number up to J = 45.5. The weak dependence of CCl laser-induced fluorescence on most plasma variables makes it nearly ideal as a simple, direct, and quantitative temperature and concentration diagnostic

  6. Synthesis of AuPd alloyed nanoparticles via room-temperature electron reduction with argon glow discharge as electron source.

    Science.gov (United States)

    Yang, Manman; Wang, Zongyuan; Wang, Wei; Liu, Chang-Jun

    2014-01-01

    Argon glow discharge has been employed as a cheap, environmentally friendly, and convenient electron source for simultaneous reduction of HAuCl4 and PdCl2 on the anodic aluminum oxide (AAO) substrate. The thermal imaging confirms that the synthesis is operated at room temperature. The reduction is conducted with a short time (30 min) under the pressure of approximately 100 Pa. This room-temperature electron reduction operates in a dry way and requires neither hydrogen nor extra heating nor chemical reducing agent. The analyses using X-ray photoelectron spectroscopy (XPS) confirm all the metallic ions have been reduced. The characterization with X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) shows that AuPd alloyed nanoparticles are formed. There also exist some highly dispersed Au and Pd monometallic particles that cannot be detected by XRD and transmission electron microscopy (TEM) because of their small particle sizes. The observed AuPd alloyed nanoparticles are spherical with an average size of 14 nm. No core-shell structure can be observed. The room-temperature electron reduction can be operated in a larger scale. It is an easy way for the synthesis of AuPd alloyed nanoparticles.

  7. Low Pressure DC Glow Discharge Air Plasma Surface Treatment of Polyethylene (PE) Film for Improvement of Adhesive Properties

    International Nuclear Information System (INIS)

    Pandiyaraj, Krishnasamy Navaneetha; Yoganand, Paramasivam; Selvarajan, Vengatasamy; Deshmukh, Rajendrasing R.; Balasubramanian, Suresh; Maruthamuthu, Sundaram

    2013-01-01

    The present work deals with the change in surface properties of polyethylene (PE) film using DC low pressure glow discharge air plasma and makes it useful for technical applications. The change in hydrophilicity of the modified PE film surface was investigated by measuring contact angle and surface energy as a function of exposure time. Changes in the morphological and chemical composition of PE films were analyzed by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The improvement in adhesion was studied by measuring T-peel and lap-shear strength. The results show that the wettability and surface energy of the PE film has been improved due to the introduction of oxygen-containing polar groups and an increase in surface roughness. The XPS result clearly shows the increase in concentration of oxygen content and the formation of polar groups on the polymer surface. The AFM observation on PE film shows that the roughness of the surface increased due to plasma treatment. The above morphological and chemical changes enhanced the adhesive properties of the PE film surfaces, which was confirmed by T-peel and lap-shear tests.

  8. Stationary striations due to interaction of two ionization waves in xenon glow discharge

    International Nuclear Information System (INIS)

    Maruyama, T.; Nishina, S.; Kitamura, H.; Itagaki, K.; Mizuochi, H.

    1990-01-01

    Experimental observations on stationary striations in the positive column of xenon discharge are reported. Stationary striations are observed when two ionization waves exist simultaneously in the positive column at low pressure and high current region. These stationary striations are caused by nonlinear interference of two backward ionization waves of which frequencies are either equal or are in the ratio 1:2. The spatial intervals for the striated pattern are equal to the reciprocal of the difference between the wave-numbers of two ionization waves. (orig.)

  9. Transition rate diagrams - A new approach to the study of selective excitation processes: The spectrum of manganese in a Grimm-type glow discharge

    Science.gov (United States)

    Weiss, Zdeněk; Steers, Edward B. M.; Pickering, Juliet C.; Mushtaq, Sohail

    2014-02-01

    The emission spectra of manganese observed using a Grimm-type glow discharge in pure argon, argon with 0.3% v/v hydrogen and pure neon were studied in order to identify major excitation and ionization processes of manganese in the plasma. A new procedure is proposed, in which each observed emission line is associated with the corresponding transition between different states of the Mn atom or Mn ion, and, by considering all the observed transitions from and into a specific state, a measure of the total rate is determined at which this state is radiatively populated and depopulated. These resulting population/depopulation rates are then plotted as function of level energy. Such plots, called here “transition rate diagrams”, show the role of individual states in the formation of the observed spectrum and can be used to identify possible selective excitation processes. Also, cascade excitation by radiative decay of higher excited states can be conveniently evaluated in this way. A detailed description of the observed Mn I and Mn II spectra is given for Ar, Ar-H2 and Ne plasmas and relevant excitation/ionization mechanisms are discussed. Matrix effects in analysis of manganese by glow discharge spectroscopy are discussed. A list of important Mn I and Mn II lines excited in the glow discharge plasma is given.

  10. The Applicability of Fluid Model to Electrical Breakdown and Glow Discharge Modeling in Argon

    International Nuclear Information System (INIS)

    Stankov, M. N.; Marković, V. Lj.; Stamenković, S. N.; Jovanović, A. P.; Petković, M. D.

    2015-01-01

    The simple fluid model, an extended fluid model, and the fluid model with nonlocal ionization are applied for the calculations of static breakdown voltages, Paschen curves and current-voltage characteristics. The best agreement with the experimental data for the Paschen curve modeling is achieved by using the model with variable secondary electron yield. The modeling of current-voltage characteristics is performed for different inter-electrode distances and the results are compared with the experimental data. The fluid model with nonlocal ionization shows an excellent agreement for all inter-electrode distances, while the extended fluid model with variable electron transport coefficients agrees well with measurements at short inter-electrode distances when ionization by fast electrons can be neglected. (physics of gases, plasmas, and electric discharges)

  11. Secondary electron emission and glow discharge properties of 12CaO·7Al2O3 electride for fluorescent lamp applications

    International Nuclear Information System (INIS)

    Watanabe, Satoru; Watanabe, Toshinari; Ito, Kazuhiro; Miyakawa, Naomichi; Ito, Setsuro; Hosono, Hideo; Mikoshiba, Shigeo

    2011-01-01

    12CaO·7Al 2 O 3 electride, a sub-nanoporous compound having a work function of 2.4 eV, was examined as a candidate cathode material in fluorescent lamps. The electron emission yield was higher and the discharge voltage was lower for 12CaO·7Al 2 O 3 than for existing cathode materials such as Ni, Mo or W; therefore, the energy consumption of the fluorescent lamps can be improved using 12CaO·7Al 2 O 3 cathodes. Prototype glow-discharge lamps using 12CaO·7Al 2 O 3 were constructed and exhibited reasonable durability.

  12. Secondary electron emission and glow discharge properties of 12CaO·7Al2O3 electride for fluorescent lamp applications.

    Science.gov (United States)

    Watanabe, Satoru; Watanabe, Toshinari; Ito, Kazuhiro; Miyakawa, Naomichi; Ito, Setsuro; Hosono, Hideo; Mikoshiba, Shigeo

    2011-06-01

    12CaO·7Al 2 O 3 electride, a sub-nanoporous compound having a work function of 2.4 eV, was examined as a candidate cathode material in fluorescent lamps. The electron emission yield was higher and the discharge voltage was lower for 12CaO·7Al 2 O 3 than for existing cathode materials such as Ni, Mo or W; therefore, the energy consumption of the fluorescent lamps can be improved using 12CaO·7Al 2 O 3 cathodes. Prototype glow-discharge lamps using 12CaO·7Al 2 O 3 were constructed and exhibited reasonable durability.

  13. Complementary low energy ion scattering and X-ray photoelectron spectroscopy characterization of polystyrene submitted to N{sub 2}/H{sub 2} glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Bonatto, F., E-mail: bonatto02@yahoo.com.br [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91509-900 (Brazil); Rovani, S. [Universidade de Caxias do Sul, Caxias do Sul, Rio Grande do Sul 95070-560 (Brazil); Kaufmann, I.R.; Soares, G.V. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91509-900 (Brazil); Baumvol, I.J.R. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91509-900 (Brazil); Universidade de Caxias do Sul, Caxias do Sul, Rio Grande do Sul 95070-560 (Brazil); Krug, C. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91509-900 (Brazil)

    2012-02-15

    Low energy ion scattering (LEIS) and X-ray photoelectron spectroscopy (XPS) were used to access the elemental composition and chemical bonding characteristics of polystyrene (PS) surfaces sequentially treated by corona and glow discharge (plasma) processing in N{sub 2}/H{sub 2} ambient. The latter has shown activity as suppressor of pathogenic Staphylococcus epidermidis biofilms. LEIS indicated that oxygen from the corona discharge process is progressively replaced by nitrogen at the PS surface. XPS shows C=N and N-C=O chemical groups as significant inhibitors of bacterial adhesion, suggesting application in medical devices.

  14. Effect of preparation conditions on the properties of glow-discharge intrinsic amorphous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, M T; Carabe, J; Gandia, J J [Inst. de Energias Renovables, CIEMAT, Madrid (Spain); Solonko, A [Inst. of High Temperatures of the USSR (IVTAN), Academy of Sciences, Moscow (USSR)

    1992-04-01

    The influence of the preparation conditions (process pressure, substrate temperature, RF-power density and deposition time/thickness) on the optical and electrical properties of intrinsic hydrogenated amorphous silicon (a-Si:H) has been investigated with the aim of optimising such films to be used as absorbent layers of a-Si:H-based p-i-n solar cells. Highly photosensitive films have been obtained at high growth rates (6.2 A s{sup -1}) in the depletion regime using a high process pressure (1000 mTorr), a moderate substrate temperature (250deg C) and a relatively high RF-power density (35.2 mW cm{sup -2}). These films have excellent properties for the application in question. (orig.).

  15. Boundary-Layer Separation Control under Low-Pressure Turbine Airfoil Conditions using Glow-Discharge Plasma Actuators

    Science.gov (United States)

    Hultgren, Lennart S.; Ashpis, David E.

    2003-01-01

    transition. Gad-el-Hak provides a review of various techniques for flow control in general and Volino discusses recent studies on separation control under low-pressure-turbine conditions utilizing passive as well as active devices. As pointed out by Volino, passive devices optimized for separation control at low Reynolds numbers tend to increase losses at high Reynolds numbers, Active devices have the attractive feature that they can be utilized only in operational regimes where they are needed and when turned off would not affect the flow. The focus in the present paper is an experimental Separation is induced on a flat plate installed in a closed-circuit wind tunnel by a shaped insert on the opposite wall. The flow conditions represent flow over the suction surface of a modem low-pressure-turbine airfoil ('Pak-B'). The Reynolds number, based on wetted plate length and nominal exit velocity, is varied from 50,000 to 300,000, covering cruise to takeoff conditions. Low (0.2%) and high (2.5%) Gee-stream turbulence intensities are set using passive grids. A spanwise-oriented phased-plasma-array actuator, fabricated on a printed circuit board, is surface- flush-mounted upstream of the separation point and can provide forcing in a wide frequency range. Static surface pressure measurements and hot-wire anemometry of the base and controlled flows are performed and indicate that the glow-discharge plasma actuator is an effective device for separation control. of active separation control using glow discharge plasma actuators.

  16. Transition rate diagrams — A new approach to the study of selective excitation processes: The spectrum of manganese in a Grimm-type glow discharge

    International Nuclear Information System (INIS)

    Weiss, Zdeněk; Steers, Edward B.M.; Pickering, Juliet C.; Mushtaq, Sohail

    2014-01-01

    The emission spectra of manganese observed using a Grimm-type glow discharge in pure argon, argon with 0.3% v/v hydrogen and pure neon were studied in order to identify major excitation and ionization processes of manganese in the plasma. A new procedure is proposed, in which each observed emission line is associated with the corresponding transition between different states of the Mn atom or Mn ion, and, by considering all the observed transitions from and into a specific state, a measure of the total rate is determined at which this state is radiatively populated and depopulated. These resulting population/depopulation rates are then plotted as function of level energy. Such plots, called here “transition rate diagrams”, show the role of individual states in the formation of the observed spectrum and can be used to identify possible selective excitation processes. Also, cascade excitation by radiative decay of higher excited states can be conveniently evaluated in this way. A detailed description of the observed Mn I and Mn II spectra is given for Ar, Ar–H 2 and Ne plasmas and relevant excitation/ionization mechanisms are discussed. Matrix effects in analysis of manganese by glow discharge spectroscopy are discussed. A list of important Mn I and Mn II lines excited in the glow discharge plasma is given. - Highlights: • We measured GD-OES spectra of Mn in Ar, Ar(H) and Ne discharges. • We determined transition rate diagrams of Mn I and Mn II in these discharges. • Using those diagrams, we identified major excitation processes involved

  17. Etching of UO2 in NF3 RF Plasma Glow Discharge

    Energy Technology Data Exchange (ETDEWEB)

    Veilleux, John M. [Univ. of California, Berkeley, CA (United States)

    1999-08-01

    A series of room temperature, low pressure (10.8 to 40 Pa), low power (25 to 210 W) RF plasma glow discharge experiments with UO2 were conducted to demonstrate that plasma treatment is a viable method for decontaminating UO2 from stainless steel substrates. Experiments were conducted using NF3 gas to decontaminate depleted uranium dioxide from stainless-steel substrates. Depleted UO2 samples each containing 129.4 Bq were prepared from 100 microliter solutions of uranyl nitrate hexahydrate solution. The amorphous UO2 in the samples had a relatively low density of 4.8 gm/cm3. Counting of the depleted UO2 on the substrate following plasma immersion was performed using liquid scintillation counting with alpha/beta discrimination due to the presence of confounding beta emitting daughter products, 234Th and 234Pa. The alpha emission peak from each sample was integrated using a gaussian and first order polynomial fit to improve quantification. The uncertainties in the experimental measurement of the etched material were estimated at about ± 2%. Results demonstrated that UO2 can be completely removed from stainless-steel substrates after several minutes processing at under 200 W. At 180 W and 32.7 Pa gas pressure, over 99% of all UO2 in the samples was removed in just 17 minutes. The initial etch rate in the experiments ranged from 0.2 to 7.4 μm/min. Etching increased with the plasma absorbed power and feed gas pressure in the range of 10.8 to 40 Pa. A different pressure effect on UO2 etching was also noted below 50 W in which etching increased up to a maximum pressure, ~23 Pa, then decreased with further increases in pressure.

  18. Diagnosis of the local thermal equilibrium by optical emission spectroscopy in the evolution of electric discharge; Diagnostico del equilibrio termico local por espectroscopia optica de emision en la evolucion de una descarga electrica

    Energy Technology Data Exchange (ETDEWEB)

    Valdivia B, R.; Pacheco S, J.; Pacheco P, M.; Ramos F, F.; Cruz A, A. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Velazquez P, S. [Instituto Tecnologico de Toluca, Av. Instituto Tecnologico s/n, Ex-Rancho la Virgen, Metepec 52140, Estado de Mexico (Mexico)

    2008-07-01

    In this work applies the technique of optical emission spectroscopy to diagnose the temperature of the species generated in plasma in the transition to glow discharge arc. Whit this diagnosis is possible to determine the local thermal equilibrium conditions of the discharge. (Author)

  19. Comparison of electrical and optical characteristics in gas-phase and gas-liquid phase discharges

    Energy Technology Data Exchange (ETDEWEB)

    Qazi, H. I. A.; Li, He-Ping, E-mail: liheping@tsinghua.edu.cn; Zhang, Xiao-Fei; Bao, Cheng-Yu [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Nie, Qiu-Yue [School of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin, Heilongjiang Province 150001 (China)

    2015-12-15

    This paper presents an AC-excited argon discharge generated using a gas-liquid (two-phase) hybrid plasma reactor, which mainly consists of a powered needle electrode enclosed in a conical quartz tube and grounded deionized water electrode. The discharges in the gas-phase, as well as in the two-phase, exhibit two discharge modes, i.e., the low current glow-like diffuse mode and the high current streamer-like constrict mode, with a mode transition, which exhibits a negative resistance of the discharges. The optical emission spectral analysis shows that the stronger diffusion of the water vapor into the discharge region in the two-phase discharges boosts up the generation of OH (A–X) radicals, and consequently, leads to a higher rotational temperature in the water-phase plasma plume than that of the gas-phase discharges. Both the increase of the power input and the decrease of the argon flow rate result in the increase of the rotational temperature in the plasma plume of the water-phase discharge. The stable two-phase discharges with a long plasma plume in the water-phase under a low power input and gas flow rate may show a promising prospect for the degradation of organic pollutants, e.g., printing and dyeing wastewater, in the field of environmental protection.

  20. Sound spectrum of a pulsating optical discharge

    Energy Technology Data Exchange (ETDEWEB)

    Grachev, G N; Smirnov, A L; Tishchenko, V N [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation); Dmitriev, A K; Miroshnichenko, I B [Novosibirsk State Technical University (Russian Federation)

    2016-02-28

    A spectrum of sound of an optical discharge generated by a repetitively pulsed (RP) laser radiation has been investigated. The parameters of laser radiation are determined at which the spectrum of sound may contains either many lines, or the main line at the pulse repetition rate and several weaker overtones, or a single line. The spectrum of sound produced by trains of RP radiation comprises the line (and overtones) at the repetition rate of train sequences and the line at the repetition rate of pulses in trains. A CO{sub 2} laser with the pulse repetition rate of f ≈ 3 – 180 kHz and the average power of up to 2 W was used in the experiments. (optical discharges)

  1. Surface enrichment with chrome and nitriding of IF steel under an abnormal glow discharge; Enriquecimento superficial com cromo e nitretacao do aco IF em descarga eletrica em regime anormal

    Energy Technology Data Exchange (ETDEWEB)

    Meira, S.R.; Borges, P.C., E-mail: sabrina.r.meira@gmail.com [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Grupo de Materiais; Bernardelli, E.A. [Instituto Federal do Parana (IFPR), Paranagua, PR (Brazil). Laboratorio de Materiais

    2014-07-01

    The objective of this work is to evaluate the influence of surface enrichment of IF steel with chrome, and nitriding, the formation of the nitrided layer. Thus, IF steel samples were subjected to surface enrichment process, using 409 stainless steel as a target for sputtering, followed by plasma nitriding, both under a dc abnormal glow discharge. The enrichment treatment was operated at 1200 ° C for 3h. The nitriding treatment was operated at 510 ° C for 2 h. The influence of the treatments on the layers formed was studied through optical microscopy (OM), scan electron microscopy (SEM), X-ray diffraction (XRD) and Vickers microindentation. The results show that the enrichment is effective to enrich the IF surface, furthermore, improves the characteristics of nitriding, comparing nitriding samples to nitriding and enriched, was observed needles of nitrides, as well as a higher hardness, which is associated with the nitrides of chrome, on the nitriding and enriched samples. (author)

  2. Study of the excitation mechanisms of the second positive system in the negative glow of a N{sub 2}-Ar discharge

    Energy Technology Data Exchange (ETDEWEB)

    Isola, L; Lopez, M; Gomez, B J, E-mail: isola@ifir-conicet.gov.ar [Instituto de Fisica Rosario (CONICET-UNR) 27 Febrero 210 Bis. (S2000EZP) Rosario (Argentina)

    2011-09-21

    In an Ar-N{sub 2} discharge, the high excitation transfer from Ar({sup 3}P{sub 2,0}) to N{sub 2} produces an overpopulation of the high rotational levels of the bands of the second positive system (SPS), and so the spectra interpretation is not straightforward. This paper presents a fit function for the SPS bands measured in Ar-N{sub 2}, which allows us to study the excitation process contributions to the N{sub 2}(C) level. The procedure was tested in the negative glow of a pulsed Ar-N{sub 2} discharge at a pressure of 2.5 Torr, for different mixture concentrations. In this discharge, through the fitting, it was possible to calculate the variation of the N{sub 2}(C) densities produced by different excitation processes as well as the variation of Ar metastable density.

  3. Laser-fusion target fabrication: application of organic coatings to metallic and nonmetallic micropellets by the glow-discharge polymerization of p-xylene

    International Nuclear Information System (INIS)

    Simonsic, G.A.

    1976-01-01

    Laser-fusion targets require thin, uniform organic-film coatings. A coating technique involving glow-discharge polymerization is described for applying highly adherent, extremely uniform, thin films of a high-temperature polymer to a variety of microsubstrates. Polymeric coatings as thick as 10 μm have been successfully deposited on hollow, spherical, 40- to 250-μm-diam micropellets of glass, metal-coated glass, and nickel/manganese alloy. Experimental yields of coatings of a quality acceptable for laser-fusion targets are typically greater than 90 percent

  4. Sputter crater formation in the case of microsecond pulsed glow discharge in a Grimm-type source. Comparison of direct current and radio frequency modes

    Science.gov (United States)

    Efimova, Varvara; Hoffmann, Volker; Eckert, Jürgen

    2012-10-01

    Depth profiling with pulsed glow discharge is a promising technique. The application of pulsed voltage for sputtering reduces the sputtering rate and thermal stress and hereby improves the analysis of thin layered and thermally fragile samples. However pulsed glow discharge is not well studied and this limits its practical use. The current work deals with the questions which usually arise when the pulsed mode is applied: Which duty cycle, frequency and pulse length must be chosen to get the optimal sputtering rate and crater shape? Are the well-known sputtering effects of the continuous mode valid also for the pulsed regime? Is there any difference between dc and rf pulsing in terms of sputtering? It is found that the pulse length is a crucial parameter for the crater shape and thermal effects. Sputtering with pulsed dc and rf modes is found to be similar. The observed sputtering effects at various pulsing parameters helped to interpret and optimize the depth resolution of GD OES depth profiles.

  5. Effect of explosion hardening on the properties of the near-surface layer of glow-discharged nitrided 33H3MF steel

    International Nuclear Information System (INIS)

    Rudnicki, J.; Fleszar, A.; Wierzchon, T.; Maranda, A.; Nowaczewski, J.

    1999-01-01

    The study was concerned with the effect of explosion hardening of 33H3MF steel, realized by the impact of the detonation products of a metallic plate driven by the detonation of an explosive plastic material, upon the microhardness and thickness of the nitrided layers forming during the glow discharge assisted nitridation process. Nitrided layers containing a compound zone, diffusion layers and layers with braunite content were formed on explosion-hardened steel surfaces. The corrosion resistance of the nitrided layers thus obtained was compared with that of the layers formed on non-hardened surfaces and on non-hardened and nitrided surfaces. The layers examined have a higher corrosion resistance than the starting material, but lower than the nitrided layers formed without the explosive load. The impact strength of the steel samples was examined before and after the explosion hardening and also after glow discharge assisted nitriding. It has been found that the explosion hardening followed by nitriding increases the impact strength, which is an advantageous effect. This also gives evidence that the changes in the hardness and structure of the samples examined, which are only observed in the layers whose thickness falls between 0.1 and 1.5 mm do not affect the notch present on the sample surface and thus have no influence upon the character of the sample fracture. (author)

  6. Secondary electron emission and glow discharge properties of 12CaOcenterdot7Al2O3 electride for fluorescent lamp applications

    Directory of Open Access Journals (Sweden)

    Satoru Watanabe, Toshinari Watanabe, Kazuhiro Ito, Naomichi Miyakawa, Setsuro Ito, Hideo Hosono and Shigeo Mikoshiba

    2011-01-01

    Full Text Available 12CaOcenterdot7Al2O3 electride, a sub-nanoporous compound having a work function of 2.4 eV, was examined as a candidate cathode material in fluorescent lamps. The electron emission yield was higher and the discharge voltage was lower for 12CaOcenterdot7Al2O3 than for existing cathode materials such as Ni, Mo or W; therefore, the energy consumption of the fluorescent lamps can be improved using 12CaOcenterdot7Al2O3 cathodes. Prototype glow-discharge lamps using 12CaOcenterdot7Al2O3 were constructed and exhibited reasonable durability.

  7. Properties of films and p-i-n photo-transformed structures on the basis of a-Si:H and its alloys, received in glow discharge of a constant current

    International Nuclear Information System (INIS)

    Tauasarov, K.

    1997-01-01

    The work devoted to investigation and control of structural, optical and photoelectric properties of films of amorphous hydrogenated silicon and its alloys, deposited in glow discharge of a constant current were done, creation of photo transformed p-i-n structures investigation its photoelectric characteristics. The main results and conclusions: A new method of deposition in glow discharge of a constant current qualitative doping and un doping a-Si:H layer and p-i-n structures on the basis of amorphous hydrogenated silicon was developed. For reception of amorphous p + and n - films for first time synthesised and applied mono-silborina and mono-silphosfin, containing pointed Si-B and Si-P linkages. New layered linear - organized structure in the films a-Si:H (T=200 deg C) was found out with distance between layers 7,5 A-o. Degree of crystallinity from combinational spectrum was determined. Concentration of films and connection between a hydrogen and silicon was determined from a IR-spectrum. It was shown that introduction of vary zone p + layer from a-Si x C 1-x :H into photo transformed p-i-n structure on the basis of a-Si:H results to decreasing of recombination losses in the area of p-i hetero boundary, and as result a photosensitive in the short-wave area of a spectrum increased. Best p-i-n structures in condition of natural illumination had following parameters: density of current of short circuit I sc =12,9 m A/cm 2 , voltage in single course U lm =0,85 V, factor of Ff.=0,55 filling and h=7% efficiency. (author)

  8. Electrical and optical characteristics of the radio frequency surface dielectric barrier discharge plasma actuation

    International Nuclear Information System (INIS)

    Wang Wei-Long; Song Hui-Min; Li Jun; Jia Min; Wu Yun; Jin Di

    2016-01-01

    Electrical characteristics and optical emission spectrum of the radio frequency (RF) surface dielectric barrier discharge (SDBD) plasma actuation are investigated experimentally in this paper. Influences of operating pressure, duty cycle and load power on the discharge are analyzed. When the operating pressure reaches 30 kPa, the discharge energy calculated from the Charge–Voltage (Q–V) Lissajous figure increases significantly, while the effective capacitance decreases remarkably. As the duty cycle of the applied voltage increases, the voltage–current waveforms, the area of Q–V loop and the capacity show no distinct changes. Below 40 W, effective capacitance increases with the increase of load power, but it almost remains unchanged when load power is between 40 W and 95 W. The relative intensity changes little as the operating pressure varies from 4 kPa to 100 kPa, while it rises evidently with the pressure below 4 kPa, which indicates that the RF discharge mode shifts from filamentary discharge to glow discharge at around 4 kPa. With the increase of load power, the relative intensity rises evidently. Additionally, the relative intensity is insensitive to the pressure, the duty cycle, and the load power. (paper)

  9. Analysis of the Thermoluminescence Glow Curves of a Brown Microcline - Effects of Optical Bleaching Upon the Trap Distribution

    International Nuclear Information System (INIS)

    Sakurai, T.; Gartia, R.K.

    1999-01-01

    Glow peaks of thermoluminescence emitted from a brown microcline (feldspar, a triclinic form of KAlSi 3 O 8 ) are numerically analysed with a model in which the traps are exponentially distributed. The Brown microcline is irradiated by γ rays for 1 h and then after 40 days bleached with white light. The best-fit trap parameters the width and the characteristic depth of the traps, the rates of recombination and retrapping of the released electrons, and the concentration of thermally disconnected traps are found for two bleaching durations (5 and 30 min). The width of continuous distribution decreases and results in a final disappearance owing to optical bleaching. This leads to the conclusion that the variation in the surroundings of the defects produced by γ ray irradiation are reduced as a result of optical bleaching. (author)

  10. Degradation of Remazol Red in batik dye waste water by contact glow discharge electrolysis method using NaOH and NaCl electrolytes

    Science.gov (United States)

    Saksono, Nelson; Putri, Dita Amelia; Suminar, Dian Ratna

    2017-03-01

    Contact Glow Discharge Electrolysis (CGDE) method is one of Plasma Electrolysis technology which has been approved to degrade organic waste water because it is very productive in producing hydroxyl radical. This study aims to degrade Remazol Red by CGDE method and evaluate important parameters that have influent in degradation process of Remazol Red in Batik dye waste water in batch system. The kind of electrolyte (acid and base) and the addition of metal ion such as Fe2+ have affected Remazol Red degradation percentage. Ultraviolet-Visible (UV-Vis) absorption spectra were used to monitor the degradation process. The result of study showed that percentage degradation was 99.97% which obtained by using NaCl 0.02 M with addition Fe2+ 20 ppm, applied voltage 700 volt, anode depth 0.5 cm, initial concentration of Remazol Red 250 ppm and the temperature of solutions was maintained 50-60 ˚C.

  11. Morphological and surface compositional changes in poly(lactide-co-glycolide) tissue engineering scaffolds upon radio frequency glow discharge plasma treatment

    International Nuclear Information System (INIS)

    Djordjevic, Ivan; Britcher, Leanne G.; Kumar, Sunil

    2008-01-01

    Chemical functionalisation of polymeric scaffolds with functional groups such as amine could provide optimal conditions for loading of signalling biomolecules over the entire volume of the porous scaffolds. Three-dimensional (both surface and bulk) functionlisation of large volume scaffolds is highly desirable, but preferably without any change to the basic morphological, structural and bulk chemical properties of the scaffolds. In this work, we have carried out and compared treatments of poly(lactide-co-glycolide) tissue engineering scaffolds by two methods, that is, a wet chemical method using ethylenediamine and a glow discharge plasma method using heptylamine as a precursor. The samples thus prepared were analysed by scanning electron microscopy and X-ray photoelectron spectroscopy. The plasma treatment generated amide and protonated amine (NH + ) groups which were present in the bulk and on the surface of the scaffold. Amination also occurred for the wet chemical treatments but the structural and chemical integrity were adversely affected

  12. Morphological and surface compositional changes in poly(lactide-co-glycolide) tissue engineering scaffolds upon radio frequency glow discharge plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    Djordjevic, Ivan [Ian Wark Research Institute, University of South Australia, Mawson Lakes, Adelaide, SA 5095 (Australia); Britcher, Leanne G. [Ian Wark Research Institute, University of South Australia, Mawson Lakes, Adelaide, SA 5095 (Australia)], E-mail: Leanne.Britcher@unisa.edu.au; Kumar, Sunil [Ian Wark Research Institute, University of South Australia, Mawson Lakes, Adelaide, SA 5095 (Australia)

    2008-01-30

    Chemical functionalisation of polymeric scaffolds with functional groups such as amine could provide optimal conditions for loading of signalling biomolecules over the entire volume of the porous scaffolds. Three-dimensional (both surface and bulk) functionlisation of large volume scaffolds is highly desirable, but preferably without any change to the basic morphological, structural and bulk chemical properties of the scaffolds. In this work, we have carried out and compared treatments of poly(lactide-co-glycolide) tissue engineering scaffolds by two methods, that is, a wet chemical method using ethylenediamine and a glow discharge plasma method using heptylamine as a precursor. The samples thus prepared were analysed by scanning electron microscopy and X-ray photoelectron spectroscopy. The plasma treatment generated amide and protonated amine (NH{sup +}) groups which were present in the bulk and on the surface of the scaffold. Amination also occurred for the wet chemical treatments but the structural and chemical integrity were adversely affected.

  13. Mechanical and tribological properties of AISI 304 stainless steel nitrided by glow discharge compared to ion implantation and plasma immersion ion implantation

    International Nuclear Information System (INIS)

    Foerster, C.E.; Serbena, F.C.; Silva, S.L.R. da; Lepienski, C.M.; Siqueira, C.J. de M.; Ueda, M.

    2007-01-01

    Results about mechanical and tribological behavior of AISI 304 stainless steel nitrided by three different ion beam processes - glow discharge (GD), ion implantation (II) and plasma immersion ion implantation (PI3) are reported. Expanded austenite γ N and nitrides phases (Fe 2+x N, γ'-Fe 4 N and Cr-N) were identified as a function of nitriding conditions. Hardness (H) and elastic modulus (E) profiles were obtained by instrumented penetration. The hardness reached values as high as 21 GPa by PI3. Tribological behavior was studied by reciprocating sliding tests with a WC (Co) ball at room temperature (RT) in dry condition. Different wear regimes were identified in the friction coefficient profiles. The profile form and the running-in distance are strongly dependent on the nitriding process. Adhesive and abrasive wear components can be inferred from these friction profiles. Hardness and tribological performance, after the nitriding processes, are discussed in terms of surface microstructure

  14. Optical signatures of discharges in parallel coupled DC accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Rajan, Rehim N.; Banerjee, Srutarshi; Acharya, S.N., E-mail: rehim@barc.gov.in [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Mumbai (India); and others

    2014-07-01

    Parallel coupled voltage multiplier based accelerator topologies offer advantages of better regulation and ripple compared to their series coupled counterparts for Industrial electron beam accelerators. During conditioning and operation these systems undergoes various types of electrical discharges. The discharge can be a direct spark over from the high voltage terminal to ground through SF{sub 6} insulation, vacuum breakdown in the accelerating tube maintained in the order of 10{sup -7} mbar pressure, or local discharge between corona guards which are used to couple RF power to the multiplier. There could be discharges in between dynodes of the accelerating tube. As the inter electrode discharges do not reflect in load current, detection of these conditions becomes very difficult. Optical discharge detection methods can be used effectively in this situation. Photo multiplier based optical discharge detection has been deployed in a 3 MeV DC accelerator. Characteristics of the optical signal received during conditioning phase have been presented in this paper. (author)

  15. Influence of oxygen gas on characteristics of self-organized luminous pattern formation observed in an atmospheric dc glow discharge using a liquid electrode

    International Nuclear Information System (INIS)

    Shirai, Naoki; Uchida, Satoshi; Tochikubo, Fumiyoshi

    2014-01-01

    Self-organized luminous pattern formation is observed in the liquid surface of an atmospheric dc glow discharge using a liquid electrode with a miniature helium flow. The factors affecting pattern formation are the gap length, discharge current, helium mass flow rate and polarity. The pattern shape depends on the conductivity and temperature of the liquid electrode. A variety of patterns were observed by changing the conductivity and temperature of the liquid. We clarified that the self-organized pattern formation depends on the amount of electronegative gas, such as oxygen, in the gas in the electrode gap. When an oxygen gas flow was fed to the liquid surface from the outside in an obliquely downward direction, namely, the amount of oxygen gas on the liquid surface was increased locally, self-organized pattern formation was observed in the region with the increased amount of oxygen gas. When the amount of oxygen in the gas in the gap was changed by using a sheath flow system, the appearance of the pattern changed. The presence of oxygen gas strongly affected the self-organized pattern formation of the atmospheric dc discharge using a liquid anode. (paper)

  16. Spatiotemporally resolved characteristics of a gliding arc discharge in a turbulent air flow at atmospheric pressure

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas

    2017-01-01

    A gliding arc discharge was generated in a turbulent air flow at atmospheric pressure driven by a 35 kHz alternating current (AC) electric power. The spatiotemporally resolved characteristics of the gliding arc discharge, including glow-type discharges, spark-type discharges, short-cutting events...... and transitions among the different types of discharges, were investigated using simultaneously optical and electrical diagnostics. The glow-type discharge shows sinusoidal-like voltage and current waveforms with a peak current of hundreds of milliamperes. The frequency of the emission intensity variation...... of the glow-type discharge is the same as that of the electronic power dissipated in the plasma column. The glow-type discharge can transfer into a spark discharge characterized by a sharp peak current of several amperes and a sudden increase of the brightness in the plasma column. Transitions can also...

  17. Glow discharge polymerization of α-aminopropyl triethoxy silane and the structure and properties of its polymers

    International Nuclear Information System (INIS)

    Wang Shicai; Zhou Maotang; Chen Jie

    1992-01-01

    In a capacitively coupled discharge apparatus with external electrodes, α-amonopropyltriethoxysilane (APTEOS) were polymerized and the effects of system pressure, discharge power and plasma gas on the polymerization rate were investigated. The polymer structure was studied by means of X ray diffraction, IR spectroscopy and element analysis. Some polymer properties such as thermostability, hydrophobicity and surface energy were also studied

  18. Study of the striated nature of a glow discharge.; Estudio de la naturaleza estratificada de una descarga de resplandor.

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez A, M

    1995-10-01

    In an investigation in progress here, plasma diagnostics and detection of standing and moving striations is being made in a discharge in Argon at pressures of 2 x 10{sup -1} to 9 x 10{sup -1} mb and currents of 2 to 9 m-amp inside an discharge tube. Measurement of the temperature of the electrons, the concentration of electrons and the plasma potential are obtained in different places of the discharge by the double probe method, together with the computation system reported in [1]. In similar way an experimental work of the striated column in a discharge plasma to find the regimen of appearance of the standing and moving striations show some properties of moving striations (frequency and velocity) and standing striations. Two different oscilations are observed in motion in contrary directions along the discharge tube with a photomultiplier. (Author).

  19. Deviation from Boltzmann distribution in excited energy levels of singly-ionized iron in an argon glow discharge plasma for atomic emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lei; Kashiwakura, Shunsuke; Wagatsuma, Kazuaki, E-mail: wagatuma@imr.tohoku.ac.jp

    2012-01-15

    A Boltzmann plot for many iron ionic lines having excitation energies of 4.7-9.1 eV was investigated in an argon glow discharge plasma when the discharge parameters, such as the voltage/current and the gas pressure, were varied. A Grimm-style radiation source was employed in a DC voltage range of 400-800 V at argon pressures of 400-930 Pa. The plot did not follow a linear relationship over a wide range of the excitation energy, but it yielded a normal Boltzmann distribution in the range of 4.7-5.8 eV and a large overpopulation in higher-lying excitation levels of iron ion. A probable reason for this phenomenon is that excitations for higher excited energy levels of iron ion would be predominantly caused by non-thermal collisions with argon species, the internal energy of which is received by iron atoms for the ionization. Particular intense ionic lines, which gave a maximum peak of the Boltzmann plot, were observed at an excitation energy of ca. 7.7 eV. They were the Fe II 257.297-nm and the Fe II 258.111-nm lines, derived from the 3d{sup 5}4s4p {sup 6}P excited levels. The 3d{sup 5}4s4p {sup 6}P excited levels can be highly populated through a resonance charge transfer from the ground state of argon ion, because of good matching in the excitation energy as well as the conservation of the total spin before and after the collision. An enhancement factor of the emission intensity for various Fe II lines could be obtained from a deviation from the normal Boltzmann plot, which comprised the emission lines of 4.7-5.8 eV. It would roughly correspond to a contribution of the charge transfer excitation to the excited levels of iron ion, suggesting that the charge-transfer collision could elevate the number density of the corresponding excited levels by a factor of ca.10{sup 4}. The Boltzmann plots give important information on the reason why a variety of iron ionic lines can be emitted from glow discharge plasmas.

  20. One-step preparation of nanostructured martite catalyst and graphite electrode by glow discharge plasma for heterogeneous electro-Fenton like process.

    Science.gov (United States)

    Khataee, Alireza; Sajjadi, Saeed; Hasanzadeh, Aliyeh; Vahid, Behrouz; Joo, Sang Woo

    2017-09-01

    Natural Martite ore particles and graphite were modified by alternating current (AC) glow discharge plasma to form nanostructured catalyst and cathode electrode for using in the heterogeneous-electro Fenton-like (Het-EF-like) process. The performance of the plasma-treated martite (PTM) and graphite electrode (PTGE) was studied for the treatment of paraquat herbicide in a batch system. 85.78% degradation efficiency for 20 mg L -1 paraquat was achieved in the modified process under desired operational conditions (i.e. current intensity of 300 mA, catalyst amount of 1 g L -1 , pH = 6, and background electrolyte (Na 2 SO 4 ) concentration of 0.05 mol L -1 ) which was higher than the 41.03% for the unmodified one after 150 min of treatment. The ecofriendly modification of the martite particles and the graphite electrode, no chemical needed, low leached iron and milder operational pH were the main privileges of plasma utilization. Moreover, the degradation efficiency through the process was not declined after five repeated cycles at the optimized conditions, which proved the stability of the nanostructured PTM and PTGE in the long-term usage. The archived results exhibit this method is the first example of high efficient, cost-effective, and environment-friendly method for generation of nanostructured samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Morphological and Structural Analysis of Polyaniline and Poly(o-anisidine Layers Generated in a DC Glow Discharge Plasma by Using an Oblique Angle Electrode Deposition Configuration

    Directory of Open Access Journals (Sweden)

    Bogdan Butoi

    2017-12-01

    Full Text Available This work is focused on the structural and morphological investigations of polyaniline and poly(o-anisidine polymers generated in a direct current glow discharge plasma, in the vapors of the monomers, without a buffer gas, using an oblique angle-positioned substrate configuration. By atomic force microscopy and scanning electron microscopy we identified the formation of worm-like interlinked structures on the surface of the polyaniline layers, the layers being compact in the bulk. The poly(o-anisidine layers are flat with no kind of structures on their surfaces. By Fourier transform infrared spectroscopy we identified the main IR bands characteristic of polyaniline and poly(o-anisidine, confirming that the polyaniline chemical structure is in the emeraldine form. The IR band from 1070 cm−1 was attributed to the emeraldine salt form of polyaniline as an indication of its doping with H+. The appearance of the IR band at 1155 cm−1 also indicates the conducting protonated of polyaniline. The X-ray diffraction revealed the formation of crystalline domains embedded in an amorphous matrix within the polyaniline layers. The interchain separation length of 3.59 Å is also an indicator of the conductive character of the polymers. The X-ray diffraction pattern of poly(o-anisidine highlights the semi-crystalline nature of the layers. The electrical conductivities of polyaniline and poly(o-anisidine layers and their dependence with temperature are also investigated.

  2. The Influence Of Nitridation Temperature And Time On The Surface Hardness Of AISI 1010 Low Carbon Steels Nitrided By Means Of Plasma Glow Discharge Technique

    International Nuclear Information System (INIS)

    Sujitno, Tjipto; Mujiman, Supardjono

    1996-01-01

    The results of the influence of nitridation temperature and time on the surface hardness of AISI 1010 low carbon steels nitrided by means of plasma glow discharge technique are presented in this paper. The results are the changing of surface hardiness, the changing of surface microstructure and the penetration profile depth. The experiment has been carried out at the temperature 400 o C, 450 o C, 500 o C, 550 o C, 570 o C and 600 o C, whereas the time is 5 minutes, 15 minutes, 40 minutes, 90 minutes and 180 minutes. All the experiments have been carried out at the optimum plasma density condition. The optimum plasma density condition is achieved at the pressure of p = 0.2 torr, when thr gas flow of nitrogen is 0.6 liter/minute and the distance of electrode plate is 4.5 cm. It was found that the optimum hardness of the surface was achieved at the temperature of 570 o C and the time of nitridation was 90 minutes, i.e. 190 KHN

  3. The effect of axial ion parameters on the properties of glow discharge polymer in T2B/H2 plasma

    Science.gov (United States)

    Ai, Xing; He, Xiao-Shan; Huang, Jing-Lin; He, Zhi-Bing; Du, Kai; Chen, Guo

    2018-03-01

    Glow discharge polymer (GDP) films were fabricated using plasma-enhanced chemical vapor deposition. The main purpose of this work was to explore the correlations of plasma parameters with the surface morphology and chemical structure of GDP films. The intensities of main positive ions and ion energy as functions of axial distances in T2B/H2 plasma were diagnosed using energy-resolved mass spectrometry. The surface morphology and chemical structure were characterized as functions of axial distances using a scanning electron microscope and Fourier transform infrared spectroscopy, respectively. As the axial distance increases, both the intensities of positive ions and high energy ions decreases, and dissociation weakens while polymerization enhances. This leads to the weakening of the cross-linking structure of GDP films and the formation of dome defects on films. Additionally, high energy ions could introduce a strong etching effect to form etching pits. Therefore, an axial distance of about 20 mm was found to be the optimal plasma parameter to prepare the defect-free GDP films. These results could help one to find the optimal plasma parameters for GDP film deposition.

  4. The Influence of CO2 Admixtures on the Product Composition in a Nitrogen-Methane Atmospheric Glow Discharge Used as a Prebiotic Atmosphere Mimic.

    Science.gov (United States)

    Mazankova, V; Torokova, L; Krcma, F; Mason, N J; Matejcik, S

    2016-11-01

    This work extends our previous experimental studies of the chemistry of Titan's atmosphere by atmospheric glow discharge. The Titan's atmosphere seems to be similarly to early Earth atmospheric composition. The exploration of Titan atmosphere was initiated by the exciting results of the Cassini-Huygens mission and obtained results increased the interest about prebiotic atmospheres. Present work is devoted to the role of CO 2 in the prebiotic atmosphere chemistry. Most of the laboratory studies of such atmosphere were focused on the chemistry of N 2  + CH 4 mixtures. The present work is devoted to the study of the oxygenated volatile species in prebiotic atmosphere, specifically CO 2 reactivity. CO 2 was introduced to the standard N 2  + CH 4 mixture at different mixing ratio up to 5 % CH 4 and 3 % CO 2 . The reaction products were characterized by FTIR spectroscopy. This work shows that CO 2 modifies the composition of the gas phase with the detection of oxygenated compounds: CO and others oxides. There is a strong influence of CO 2 on increasing concentration other products as cyanide (HCN) and ammonia (NH 3 ).

  5. Nmr and esr studies on a-Si/sub 1-x/Ge/sub x/:H films prepared by glow discharge and magnetron sputtering

    International Nuclear Information System (INIS)

    Shimizu, T.; Kumeda, M.; Morimoto, A.; Tsujimura, Y.; Kobayashi, I.

    1986-01-01

    Properties of a-Si/sub 1-x/Ge/sub x/:H films prepared by magnetron sputtering (MG) and glow discharge decomposition (GD) were compared by means of NMR, ESR, IR and hydrogen-evolution measurements. For MG films, the content of dispersed H is roughly independent of x while the content of clustered H decreases with x. For GD films, both the contents of dispersed and clustered H decrease with x. ESR results reveal that most defects in the films are Ge dangling bonds and that the number of dangling bonds per Ge atom is roughly independent of x for MG films whereas it increases largely with x for GD films. The ratio of the intensity of the IR peak at 2100 cm/sup -1/ to that at 2000 cm/sup -1/ decreases and increases with x, respectively, for MG and GD films, and the ratio of the intensity of the low temperature H evolution peak to that of the high temperature H evolution peak decreases and increases with x, respectively for MG and GD films

  6. Hydrogen retention studies on lithiated tungsten exposed to glow discharge plasmas under varying lithiation environments using Thermal Desorption Spectroscopy and mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Castro, A. de, E-mail: alfonso.decastro@ciemat.es [Fusion National Laboratory-CIEMAT, Av Complutense 40, 28040 Madrid (Spain); Valson, P. [Max-Planck-Institut für Plasmaphysik, Wendelsteinstraße 1, 17491 Greifswald (Germany); Tabarés, F.L. [Fusion National Laboratory-CIEMAT, Av Complutense 40, 28040 Madrid (Spain)

    2017-04-15

    For the design of a Fusion Reactor based on a liquid lithium divertor target and a tungsten first wall at high temperature, the interaction of the wall material with plasmas of significant lithium content must be assessed, as issues like fuel retention, tungsten embrittlement and enhanced sputtering may represent a showstopper for the selection of the first wall material compatible with the presence of liquid metal divertor. In this work we address this topic for the first time at the laboratory level, hot W samples (100 °C) have been exposed to Glow Discharges of H{sub 2} or Li-seeded H{sub 2} followed by in situ thermal desorption studies (TDS) of the uptake of H{sub 2} on the samples. Pure and pre-lithiated tungsten was investigated in order to evaluate the differential effect of Li ion implantation on H retention. Global particle balance was also used for the determination of trapped H into the full W wall of the plasma chamber. A factor of 3-4 lower retention was deduced for samples and main W wall exposed to H/Li plasma than that measured on pre-lithiated W.

  7. Determination of Hg(2+) by on-line separation and pre-concentration with atmospheric-pressure solution-cathode glow discharge atomic emission spectrometry.

    Science.gov (United States)

    Li, Qing; Zhang, Zhen; Wang, Zheng

    2014-10-03

    A simple and sensitive method to determine Hg(2+) was developed by combining solution-cathode glow discharge atomic emission spectrometry (SCGD-AES) with flow injection (FI) based on on-line solid-phase extraction (SPE). We synthesized l-cysteine-modified mesoporous silica and packed it in an SPE microcolumn, which was experimentally determined to possess a good mercury adsorption capacity. An enrichment factor of 42 was achieved under optimized Hg(2+) elution conditions, namely, an FI flow rate of 2.0 mL min(-1) and an eluent comprised of 10% thiourea in 0.2 mol L(-1) HNO3. The detection limit of FI-SCGD-AES was determined to be 0.75 μg L(-1), and the precision of the 11 replicate Hg(2+) measurements was 0.86% at a concentration of 100 μg L(-1). The proposed method was validated by determining Hg(2+) in certified reference materials such as human hair (GBW09101b) and stream sediment (GBW07310). Copyright © 2014. Published by Elsevier B.V.

  8. Dielectric barrier discharges applied for optical spectrometry

    Czech Academy of Sciences Publication Activity Database

    Brandt, S.; Schütz, A.; Klute, F. D.; Kratzer, Jan; Franzke, J.

    2016-01-01

    Roč. 123, SEP (2016), s. 6-32 ISSN 0584-8547 R&D Projects: GA ČR GA14-23532S Institutional support: RVO:68081715 Keywords : dielectric barrier discharge * analytical spectroscopy * applications Subject RIV: CB - Analytical Chemistry , Separation Impact factor: 3.241, year: 2016

  9. Dielectric barrier discharges applied for optical spectrometry

    Czech Academy of Sciences Publication Activity Database

    Brandt, S.; Schütz, A.; Klute, F. D.; Kratzer, Jan; Franzke, J.

    2016-01-01

    Roč. 123, SEP (2016), s. 6-32 ISSN 0584-8547 R&D Projects: GA ČR GA14-23532S Institutional support: RVO:68081715 Keywords : dielectric barrier discharge * analytical spectroscopy * applications Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.241, year: 2016

  10. Bio-compatibility, surface and chemical characterization of glow discharge plasma modified ZnO nanocomposite polycarbonate

    Energy Technology Data Exchange (ETDEWEB)

    Bagra, Bhawna, E-mail: bhawnacct@gmail.com; Pimpliskar, Prashant, E-mail: bhawnacct@gmail.com [Centre for Converging Technologies, University of Rajasthan, Jaipur-302004 (India); Agrawal, Narendra Kumar [Department of Physics, Malaviya National Institute of Technology, Jaipur-302004 (India)

    2014-04-24

    Bio compatibility is an important issue for synthesis of biomedical devices, which can be tested by bioadoptability and creations of active site to enhance the bacterial/cell growth in biomedical devices. Hence a systematic study was carried out to characterize the effects of Nitrogen ion plasma for creations of active site in nano composite polymer membrane. Nano particles of ZnO are synthesized by chemical root, using solution casting nano composite polymeric membranes were prepared and treated with Nitrogen ion plasma. These membranes were characterized by different technique such as optical microscopy, SEM- Scanning electron microscope, optical transmittance, Fourier transform infrared spectroscopy. Then biocompatibility for membranes was tested by testing of bio-adoptability of membrane.

  11. Common Gamma-ray Glows above Thunderclouds

    Science.gov (United States)

    Kelley, Nicole; Smith, David; Dwyer, Joseph; Hazelton, Bryna; Grefenstette, Brian; Lowell, Alex; Splitt, Michael; Lazarus, Steven; Rassoul, Hamid

    2013-04-01

    Gamma-ray glows are continuous, long duration gamma- and x-ray emission seen coming from thunderclouds. The Airborne for Energetic Lightning Emissions (ADELE) observed 12 gamma-ray glows during its summer 2009 flight campaign over the areas of Colorado and Florida in the United States. For these glows we shall present their spectra, relationship to lightning activity and how their duration and size changes as a function of distance. Gamma-ray glows follow the relativistic runaway electron avalanche (RREA) spectrum and have been previously measured from the ground and inside the cloud. ADELE measured most glows as it flew above the screening layer of the cloud. During the brightest glow on August 21, 2009, we can show that we are flying directly into a downward facing relativistic runaway avalanche, indicative of flying between the upper positive and negative screening layer of the cloud. In order to explain the brightness of this glow, RREA with an electric field approaching the limit for relativistic feedback must be occurring. Using all 12 glows, we show that lightning activity diminishes during the onset of the glow. Using this along with the fact that glows occur as the field approaches the level necessary for feedback, we attempt to distinguish between two possibilities: that glows are evidence that RREA with feedback, rather than lightning, is sometimes the primary channel for discharging the cloud, or else that the overall discharging is still controlled by lightning, with glows simply appearing during times when a subsidence of lightning allows the field to rise above the threshold for RREA.

  12. Multi-species counter-current diffusion model for etching depleted uranium oxide in NF3, RF glow discharge

    International Nuclear Information System (INIS)

    Saber, H.H.; El-Genk, M.S.

    1999-01-01

    Results of recent experiments investigating the decontamination of depleted UO 2 using NF 3 gas, RF gloss discharge, showed that etching rate decreased monotonically with immersion time to the end point. In addition to the formation of non-volatile reaction products on UO 2 surface, the accumulation of UF 6 in the sheath contributed to the decrease in etch rate with immersion time. To investigate the latter, a transient, multi-species, counter-current diffusion model for UO 2 etching is developed. Model results indicated that, depending on gas pressure and absorbed power, the diffusion coefficient of F in the sheath decreased at the end point by ∼15%. At 17.0 Pa and 200 W, the mole fraction of F at UO 2 surface decreased rapidly with immersion time to 61% and 86% of its initial value, after one and two characteristic etch time, respectively, it became almost zero at the end point, reached after 4--5 characteristic etch times

  13. Flow Injection Photochemical Vapor Generation Coupled with Miniaturized Solution-Cathode Glow Discharge Atomic Emission Spectrometry for Determination and Speciation Analysis of Mercury.

    Science.gov (United States)

    Mo, Jiamei; Li, Qing; Guo, Xiaohong; Zhang, Guoxia; Wang, Zheng

    2017-10-03

    A novel, compact, and green method was developed for the determination and speciation analysis of mercury, based on flow injection photochemical vapor generation (PVG) coupled with miniaturized solution cathode glow discharge-atomic emission spectroscopy (SCGD-AES). The SCGD was generated between a miniature hollow titanium tube and a solution emerging from a glass capillary. Cold mercury vapor (Hg(0)) was generated by PVG and subsequently delivered to the SCGD for excitation, and finally the emission signals were recorded by a miniaturized spectrograph. The detection limits (DLs) of Hg(II) and methylmercury (MeHg) were both determined to be 0.2 μg L -1 . Moreover, mercury speciation analysis could also be performed by using different wavelengths and powers from the UV lamp and irradiation times. Both Hg(II) and MeHg can be converted to Hg(0) for the determination of total mercury (T-Hg) with 8 W/254 nm UV lamp and 60 s irradiation time; while only Hg(II) can be reduced to Hg(0) and determined selectively with 4 W/365 nm UV lamp and 20 s irradiation time. Then, the concentration of MeHg can be calculated by subtracting the Hg(II) from the T-Hg. Because of its similar sensitivity and DL at 8 W/254 nm, the simpler and less toxic Hg(II) was used successfully as a primary standard for the quantification of T-Hg. The novel PVG-SCGD-AES system provides not only a 365-fold improvement in the DL for Hg(II) but also a nonchromatographic method for the speciation analysis of mercury. After validating its accuracy, this method was successfully used for mercury speciation analysis of water and biological samples.

  14. Influence of Nitrided Layer on The Properties of Carbon Coatings Produced on X105CrMo17 Steel Under DC Glow-Discharge Conditions

    Directory of Open Access Journals (Sweden)

    Tomasz BOROWSKI

    2016-09-01

    Full Text Available In most cases, machine components, which come in contact with each other, are made of steel. Common steel types include 100Cr6 and X105CrMo17 are widely used in rolling bearings, which are subjected to high static loads. However, more and more sophisticated structural applications require increasingly better performance from steel. The most popular methods for improving the properties of steel is carburisation or nitriding. Unfortunately, when very high surface properties of steel are required, this treatment may be insufficient. Improvement of tribological properties can be achieved by increasing the hardness of the surface, reducing roughness or reducing the coefficient of friction. The formation of composite layers on steel, consisting of a hard nitride diffusion layer and an external carbon coating with a low coefficient of friction, seems to be a prospect with significant potential. The article describes composite layers produced on X105CrMo17 steel and defines their morphology, surface roughness and their functional properties such as: resistance to friction-induced wear, coefficient of friction and corrosion resistance. The layers have been formed at a temperature of 370°C in successive processes of: nitriding in low-temperature plasma followed by deposition of a carbon coating under DC glow-discharge conditions. An evaluation was also made of the impact of the nitrided layers on the properties and morphology of the carbon coatings formed by comparing them to coatings formed on non-nitrided X105CrMo17 steel substrates. A study of the surface topography, adhesion, resistance to friction-induced wear and corrosion shows the significant importance of the substrate type the carbon coatings are formed on.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.7532

  15. Determination of Hg{sup 2+} by on-line separation and pre-concentration with atmospheric-pressure solution-cathode glow discharge atomic emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qing [Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 200050 (China); Zhang, Zhen [Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 200050 (China); School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Wang, Zheng, E-mail: wangzheng@mail.sic.ac.cn [Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 200050 (China)

    2014-10-03

    Highlights: • A modified SBA-15 mesoporous silica (SH-SBA-15) was synthesized as a sorbent. • On-line SPE combined with SCGD-AES based on FIA was used to detect Hg{sup 2+} firstly. • A simple, low-cost Hg{sup 2+} analysis in a complex matrix was established. • The sensitive detection of Hg{sup 2+} was achieved with a detection limit of 0.75 μg L{sup −1}. - Abstract: A simple and sensitive method to determine Hg{sup 2+} was developed by combining solution-cathode glow discharge atomic emission spectrometry (SCGD-AES) with flow injection (FI) based on on-line solid-phase extraction (SPE). We synthesized L-cysteine-modified mesoporous silica and packed it in an SPE microcolumn, which was experimentally determined to possess a good mercury adsorption capacity. An enrichment factor of 42 was achieved under optimized Hg{sup 2+} elution conditions, namely, an FI flow rate of 2.0 mL min{sup −1} and an eluent comprised of 10% thiourea in 0.2 mol L{sup −1} HNO{sub 3}. The detection limit of FI–SCGD-AES was determined to be 0.75 μg L{sup −1}, and the precision of the 11 replicate Hg{sup 2+} measurements was 0.86% at a concentration of 100 μg L{sup −1}. The proposed method was validated by determining Hg{sup 2+} in certified reference materials such as human hair (GBW09101b) and stream sediment (GBW07310)

  16. Testing Ionizers for Nitrogen Discharge of Interferometer Optics

    Science.gov (United States)

    Amen, Timothy; Ugolini, Dennis

    2010-10-01

    Interferometric gravitational-wave observatories consist of suspended optics in a vacuum chamber. Charge can build up on and then discontinuously jump across an optic, creating a changing electric field, causing the optic to sway, creating a false signal. We studied possible ways to discharge an optic without damaging their reflective coatings. We tried two types of electron guns. The first was built at the University of Washington and uses an ultraviolet LED to free electrons from a magnesium target. We found the current to be three orders of magnitude less than necessary for discharge in a reasonable time. The second gun used was a Bayard-Alpert gauge. To eliminate sputtering caused by the gauge above 10-4 torr, we employed a differential pumping system. We were able to flow nitrogen gas through the main chamber at pressures between 10-2 and 10-3 torr while the gauge chamber was kept two orders of magnitude lower. We successfully discharged the optic. The discharge rate varied exponentially with charge level and operating current and nearly linearly with acceleration voltage, and peaked when the pressure was 8 x 10-3 torr in the main chamber.

  17. Influence of operating parameters on surface properties of RF glow discharge oxygen plasma treated TiO{sub 2}/PET film for biomedical application

    Energy Technology Data Exchange (ETDEWEB)

    Pandiyaraj, K. Navaneetha, E-mail: dr.knpr@gmail.com [Surface Engineering Laboratory, Department of Physics, Sri Shakthi Institute of Engineering and Technology, L and T by pass, Chinniyam Palayam (post), Coimbatore 641062 (India); Deshmukh, R.R. [Department of Physics, Institute of Chemical Technology, Matunga, Mumbai 400 019 (India); Mahendiran, R. [Surface Engineering Laboratory, Department of Physics, Sri Shakthi Institute of Engineering and Technology, L and T by pass, Chinniyam Palayam (post), Coimbatore 641062 (India); Su, Pi-G [Department of Chemistry, Chinese Culture University, Taipei 111, Taiwan (China); Yassitepe, Emre; Shah, Ismat [Department of Physics and Astronomy, Department of Materials Science and Engineering, University of Delaware, 208 Dupont Hall, Newark (United States); Perni, Stefano [School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff (United Kingdom); Prokopovich, Polina [School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff (United Kingdom); Institute of Medical Engineering and Medical Physics, School of Engineering, Cardiff University (United Kingdom); Nadagouda, Mallikarjuna N., E-mail: Nadagouda.Mallikarjuna@epamail.epa.gov [The U.S. Environmental Protection Agency, ORD, NRMRL, WSWRD, 26W. Martin Luther King Drive, Cincinnati, OH 45268 (United States)

    2014-03-01

    In this paper, a thin transparent titania (TiO{sub 2}) film was coated on the surface of flexible poly(ethylene terephthalate) (PET) film using the sol–gel method. The surface properties of the obtained TiO{sub 2}/PET film were further improved by RF glow discharge oxygen plasma as a function of exposure time and discharge power. The changes in hydrophilicity of TiO{sub 2}/PET films were analyzed by contact angle measurements and surface energy. The influence of plasma on the surface of the TiO{sub 2}/PET films was analyzed by atomic force microscopy (AFM) as well as the change in chemical state and composition that were investigated by X-ray photo electron spectroscopy (XPS). The cytotoxicity of the TiO{sub 2}/PET films was analyzed using human osteoblast cells and the bacterial eradication behaviors of TiO{sub 2}/PET films were also evaluated against Staphylococcus bacteria. It was found that the surface roughness and incorporation of oxygen containing polar functional groups of the plasma treated TiO{sub 2}/PET films increased substantially as compared to the untreated one. Moreover the increased concentration of Ti{sup 3+} on the surface of plasma treated TiO{sub 2}/PET films was due to the transformation of chemical states (Ti{sup 4+} → Ti{sup 3+}). These morphological and chemical changes are responsible for enhanced hydrophilicity of the TiO{sub 2}/PET films. Furthermore, the plasma treated TiO{sub 2}/PET film exhibited no citotoxicity against osteoblast cells and antibacterial activity against Staphylococcus bacteria which can find application in manufacturing of biomedical devices. - Graphical abstract: Mechanism of plasma treatment on the surface of TiO{sub 2}/PET films. - Highlights: • Investigated the surface properties of TiO{sub 2}/PET films modified by O{sub 2} plasma • Studied the effect of operating parameters on surface properties of TiO{sub 2}/PET films • Mechanism of the plasma treatment on TiO{sub 2}/PET was clearly investigated.

  18. Rapid analysis of pesticide residues in drinking water samples by dispersive solid-phase extraction based on multiwalled carbon nanotubes and pulse glow discharge ion source ion mobility spectrometry.

    Science.gov (United States)

    Zou, Nan; Gu, Kejia; Liu, Shaowen; Hou, Yanbing; Zhang, Jialei; Xu, Xiang; Li, Xuesheng; Pan, Canping

    2016-03-01

    An analytical method based on dispersive solid-phase extraction with a multiwalled carbon nanotubes sorbent coupled with positive pulse glow discharge ion mobility spectrometry was developed for analysis of 30 pesticide residues in drinking water samples. Reduced ion mobilities and the mass-mobility correlation of 30 pesticides were measured. The pesticides were divided into five groups to verify the separation capability of pulse glow discharge in mobility spectrometry. The extraction conditions such as desorption solvent, ionic strength, conditions of adsorption and desorption, the amounts of multiwalled carbon nanotubes, and solution pH were optimized. The enrichment factors of pesticides were 5.4- to 48.7-fold (theoretical enrichment factor was 50-fold). The detection limits of pesticides were 0.01∼0.77 μg/kg. The linear range was 0.005-0.2 mg/L for pesticide standard solutions, with determination coefficients from 0.9616 to 0.9999. The method was applied for the analysis of practical and spiked drinking water samples. All results were confirmed by high-performance liquid chromatography with tandem mass spectrometry. The proposed method was proven to be a commendably rapid screening qualitative and semiquantitative technique for the analysis of pesticide residues in drinking water samples on site. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Ways for accurate analysis of high purity materials using the glow discharge mass spectrometry (GD-MS); Wege zur genauen Charakterisierung hochreiner Materialien mit der Glimmentladungs-Massenspektrometrie (GD-MS)

    Energy Technology Data Exchange (ETDEWEB)

    Gusarova, Tamara

    2010-04-14

    The main aim of this work consists in the investigation, development and application of improved possibilities of accurate analysis of high purity materials using the solid sample technique of Glow Discharge Mass Spectrometry (GD-MS), as well as in the sensitivity enhancement of GD Optical Emission Spectrometry (GD-OES) by implicating the hollow cathode effect. The emphasis of the PhD thesis consists in the accurate quantification for GD-MS. As appropriate certified reference materials (CRMs) for calibration are lacking in most cases an accurate quantification especially for trace elements mass fractions at {mu}g kg{sup -1} level can often not be achieved. To overcome this problem and to expand the possibilities of modern GD-MS hereby, synthetic standards were applied for calibration of both high resolution GD-MS instruments ''VG 9000'' and ''Element GD''. The standards were prepared by doping of matrix powder with trace element standard solutions followed by drying and pressing the doped powder to compact pellets. With the quantification approach worked out and described here accurate analysis results with small uncertainties can be achieved for most elements of periodic table in almost every matrix composition. Furthermore direct traceability of the analytical results to the International System of Units (SI) is provided ensuring their higher metrological quality. Numerous additional systematic investigations concerning the preparation of the synthetic standards and their properties were carried out. The results of calibration of GD-MS instruments with synthetic standards for Co (Co-C), Cu, In, Fe and Zn matrices were checked by measuring CRMs. These results were also contrasted with those of other quantification approaches, as usually used in GD-MS routine. The results achieved with synthetic standards had the highest accuracy. The successful participation in the round robin test CCQM-P107 between international

  20. Towards Optical Partial Discharge Detection with Micro Silicon Photomultipliers

    Directory of Open Access Journals (Sweden)

    Ming Ren

    2017-11-01

    Full Text Available Optical detection is reliable in intrinsically characterizing partial discharges (PDs. Because of the great volume and high-level power supply of the optical devices that can satisfy the requirements in photosensitivity, optical PD detection can merely be used in laboratory studies. To promote the practical application of the optical approach in an actual power apparatus, a silicon photomultiplier (SiPM-based PD sensor is introduced in this paper, and its basic properties, which include the sensitivity, pulse resolution, correlation with PD severity, and electromagnetic (EM interference immunity, are experimentally evaluated. The stochastic phase-resolved PD pattern (PRPD for three typical insulation defects are obtained by SiPM PD detector and are compared with those obtained using a high-frequency current transformer (HFCT and a vacuum photomultiplier tube (PMT. Because of its good performances in the above aspects and its additional advantages, such as the small size, low power supply, and low cost, SiPM offers great potential in practical optical PD monitoring.

  1. Optical diagnostics of streamer discharges in atmospheric gases

    Czech Academy of Sciences Publication Activity Database

    Šimek, Milan

    2014-01-01

    Roč. 47, č. 46 (2014), s. 463001-463001 ISSN 0022-3727 R&D Projects: GA ČR(CZ) GAP205/12/1709 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100431201 Program:M Institutional support: RVO:61389021 Keywords : streamer * optical diagnostics * laser-induced fluorescence * LIF * TALIF * red-sprite Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.721, year: 2014 http://iopscience.iop.org/0022-3727/47/46/463001/pdf/0022-3727_47_46_463001.pdf

  2. Development and analytical characterization of a Grimm-type glow discharge ion source operated with high gas flow rates and coupled to a mass spectrometer with high mass resolution

    International Nuclear Information System (INIS)

    Beyer, Claus; Feldmann, Ingo; Gilmour, Dave; Hoffmann, Volker; Jakubowski, Norbert

    2002-01-01

    A Grimm-type glow discharge ion source has been developed and was coupled to a commercial inductively coupled plasma mass spectrometer (ICP-MS) with high mass resolution (Axiom, ThermoElemental, Winsford, UK) by exchanging the front plate of the ICP-MS interface system only. In addition to high discharge powers of up to 70 W, which are typical for a Grimm-type design, this source could be operated with relative high gas flow rates of up to 240 ml min -1 . In combination with a high discharge voltage the signal intensities are reaching a constant level within the first 20 s after the discharge has started. An analytical characterization of this source is given utilizing a calibration using the steel standard reference material NIST 1261A-1265A. The sensitivity for the investigated elements measured with a resolution of 4000 is in the range of 500-6000 cps μg -1 g -1 , and a relative standard deviation (R.S.D.) of the measured isotope relative to Fe of less than 8% for the major and minor components of the sample has been achieved. Limits of detection at ng g -1 levels could be obtained

  3. Amplification of the dd reaction and X radiation generation in a high-current pulse glow discharge in deuterium with the Ti cathode at 0.8-2.45 kV

    International Nuclear Information System (INIS)

    Lipson, A.G.; Rusetskij, A.S.; Karabut, A.B.; Majli, Dzh.

    2005-01-01

    The dd-reaction yield (3 MeV protons) and the soft X-ray emission from a titanium cathode surface in a periodic pulsed glow discharge in deuterium were studied. The deuteron screening potential was estimated from analysis of the dd-reaction yield as a function of the accelerating voltage. The obtained data show evidence for a significant enhancement of the dd-reaction yield in Ti in comparison to both theoretical estimates and the results of experiments using accelerators at the deuteron energies ≥ 2.5 keV. Intense emission of soft X-ray quanta was observed. The X-ray emission intensity and the dd-reaction yield enhancement strongly depend on the rate of deuterium diffusion in a thin subsurface layer of Ti cathode [ru

  4. Optical observations geomagnetically conjugate to sprite-producing lightning discharges

    Directory of Open Access Journals (Sweden)

    R. A. Marshall

    2005-09-01

    Full Text Available Theoretical studies have predicted that large positive cloud-to-ground discharges can trigger a runaway avalanche process of relativistic electrons, forming a geomagnetically trapped electron beam. The beam may undergo pitch angle and energy scattering during its traverse of the Earth's magnetosphere, with a small percentage of electrons remaining in the loss cone and precipitating in the magnetically conjugate atmosphere. In particular, N2 1P and N2+1N optical emissions are expected to be observable. In July and August 2003, an attempt was made to detect these optical emissions, called "conjugate sprites", in correlation with sprite observations in Europe near . Sprite observations were made from the Observatoire du Pic du Midi (OMP in the French Pyrenées, and VLF receivers were installed in Europe to detect causative sferics and ionospheric disturbances associated with sprites. In the Southern Hemisphere conjugate region, the Wide-angle Array for Sprite Photometry (WASP was deployed at the South African Astronomical Observatory (SAAO, near Sutherland, South Africa, to observe optical emissions with a field-of-view magnetically conjugate to the Northern Hemisphere observing region. Observations at OMP revealed over 130 documented sprites, with WASP observations covering the conjugate region successfully for 30 of these events. However, no incidences of optical emissions in the conjugate hemisphere were found. Analysis of the conjugate optical data from SAAO, along with ELF energy measurements from Palmer Station, Antarctica, and charge-moment analysis, show that the lightning events during the course of this experiment likely had insufficient intensity to create a relativistic beam.

    Keywords. Ionosphere (Ionsophere-magnetosphere interactions; Ionospheric disturbances; Instruments and techniques

  5. Optical observations geomagnetically conjugate to sprite-producing lightning discharges

    Directory of Open Access Journals (Sweden)

    R. A. Marshall

    2005-09-01

    Full Text Available Theoretical studies have predicted that large positive cloud-to-ground discharges can trigger a runaway avalanche process of relativistic electrons, forming a geomagnetically trapped electron beam. The beam may undergo pitch angle and energy scattering during its traverse of the Earth's magnetosphere, with a small percentage of electrons remaining in the loss cone and precipitating in the magnetically conjugate atmosphere. In particular, N2 1P and N2+1N optical emissions are expected to be observable. In July and August 2003, an attempt was made to detect these optical emissions, called "conjugate sprites", in correlation with sprite observations in Europe near . Sprite observations were made from the Observatoire du Pic du Midi (OMP in the French Pyrenées, and VLF receivers were installed in Europe to detect causative sferics and ionospheric disturbances associated with sprites. In the Southern Hemisphere conjugate region, the Wide-angle Array for Sprite Photometry (WASP was deployed at the South African Astronomical Observatory (SAAO, near Sutherland, South Africa, to observe optical emissions with a field-of-view magnetically conjugate to the Northern Hemisphere observing region. Observations at OMP revealed over 130 documented sprites, with WASP observations covering the conjugate region successfully for 30 of these events. However, no incidences of optical emissions in the conjugate hemisphere were found. Analysis of the conjugate optical data from SAAO, along with ELF energy measurements from Palmer Station, Antarctica, and charge-moment analysis, show that the lightning events during the course of this experiment likely had insufficient intensity to create a relativistic beam. Keywords. Ionosphere (Ionsophere-magnetosphere interactions; Ionospheric disturbances; Instruments and techniques

  6. Modulation of ionization in the plasma column of an optical discharge

    International Nuclear Information System (INIS)

    Nastoyashchii, A.F.

    1981-01-01

    Stability of the ionization in the plasma column of an optical discharge is discussed. It is shown that a plasma filament formed by a long laser spike under optical discharge conditions may break up into a chain of bright luminous layers oriented in the direction of propagation of a laser beam and characterized by a higher gas ionization (''optical striations''). A nonlinear formulation of the problem is used to find the depth of modulation of the gas ionization

  7. Propagation of an optical discharge through optical fibres upon interference of modes

    International Nuclear Information System (INIS)

    Bufetov, I A; Frolov, A A; Shubin, A V; Likhachev, M E; Lavrishchev, S V; Dianov, E M

    2008-01-01

    The propagation of an optical discharge (OD) through optical fibres upon interference of LP 01 and LP 02 modes is studied. Under these conditions after the OD propagation through the fibre, the formation of an axially-symmetric group sequence of voids with a spatial period equal to that of mode interference (200-500 μm depending on the parameters of the fibre) is observed. The groups of voids are formed near the sections of the fibre with a minimal diameter of the intensity distribution of laser radiation. Large spaces between voids in the fibre have allowed us to measure accurately the difference Δn of refractive indices of the fibre core and cladding and distribution of dopants in different cross sections of the fibre after the OD propagation. A substantial increase in Δn (up to ten times) is observed. Approximately half this increase is caused by compression and densification of the fibre material after the propagation of the optical discharge. (interaction of laser radiation with matter. laser plasma)

  8. Effect of the percentage of reinforcement on the wear in the metal matrix composites sintered with abnormal glow discharge; Efecto del porcentaje de refuerzo frente al desgaste en compuestos de matriz metalica sinterizados con descarga luminiscente anormal

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Velasquez, S.; Pineda-Triana, Y.; Aguilar-Castro, Y.; Vera-Lopez, E.

    2016-05-01

    In this study an analysis of the behavior of dry wear coefficient of a Metal Matrix Composite (MMC) in 316 stainless steel reinforced with particles of titanium carbide (TiC) according to ASTM G 99 standards, in a pin-on-disk test. In this research it is tested the effect of the percentage of reinforcement in the MMC manufactured with 3, 6 y 9% (vol.) of TiC, in samples compacted at 800 MPa, generating different values of grain size, hardness and density, they are sintered with abnormal glow discharge, at a temperature of 1200 degree centigrade ±5 degree centigrade, with a protection atmosphere H{sub 2} - N{sub 2} and a permanence time of 30 minutes. According to the results obtained it is concluded that the best condition for the MMC manufacturing, in relation to the reinforcement percentage, is the one obtained when the mixture contains 6% of TiC compacted at 800 MPa. In these conditions, it was obtained: achieving smaller grain size, the greater hardness and the lowest coefficient of friction. In this respect, it was observed that the incorporation of the ceramic particles (TiC) in a matrix of austenitic steel (316) shows significant improvements in the resistance to the wear. (Author)

  9. Electrical and optical characteristics of dielectric-barrier discharge driven by high voltage nanosecond generator

    International Nuclear Information System (INIS)

    Ahmadeev, V.V.; Kost'yuchenko, S.V.; Kudryavtsev, N.N.; Kurkin, G.A.; Vasilyak, L.M.

    1998-01-01

    Electrical and optical characteristics of the dielectric-barrier discharge in the pressure range of 10-400 Torr were investigated experimentally, particular attention being paid to the discharge homogeneity and to the energy dissipation in the discharge volume. The discharge was driven by a high-voltage pulse generator producing nanosecond high-voltage pulses with an amplitude of 20-30 kV. Air, nitrogen, and helium were used as working gases. The discharge was found to be homogeneous within a wide range of gas pressure. A power density of up to 250 mW/cm 3 has been achieved. (J.U.)

  10. [Study on Square Super-Lattice Pattern with Surface Discharge in Dielectric Barrier Discharge by Optical Emission Spectra].

    Science.gov (United States)

    Niu, Xue-jiao; Dong, Li-fang; Liu, Ying; Wang, Qian; Feng, Jian-yu

    2016-02-01

    Square super-lattice pattern with surface discharge consisting of central spots and dim spots is firstly observed in the mixture of argon and air by using a dielectric barrier discharge device with water electrodes. By observing the image, it is found that the central spot is located at the centriod of its surrounding four dim spots. The short-exposure image recorded by a high speed video camera shows that the dim spot results from the surface discharges (SDs). The brightness of the central spot and is quite different from that of the dim spot, which indicates that the plasma states of the central spot and the dim spot may be differentiated. The optical emission spectrum method is used to further study the several plasma parameters of the central spot and the dim spot in different argon content. The emission spectra of the N₂ second positive band (C³IIu --> B³ IIg) are measured, from which the molecule vibration temperatures of the central spot and the dim spot are calculated respectively. The broadening of spectral line 696.57 nm (2P₂-->1S₅) is used to study the electron densities of the central spot and the dim spot. It is found that the molecule vibration temperature and electron density of the dim spot are higher than those of the central spot in the same argon content The molecule vibration temperature and electron density of the central spot and the dim spot increase with the argon content increasing from 90% to 99.9%. The surface discharge induced by the volume discharge (VD) has the determinative effect on the formation of the dim spot The experimental results above play an important role in studying the formation mechanism of surface discharg&of square super-lattice pattern with surface discharge. In addition, the studies exert an influence on the application of surface discharge and volume discharge in different fields.

  11. Optical and electrostatic potential investigations of electrical breakdown phenomena in a low-pressure gas discharge lamp

    International Nuclear Information System (INIS)

    Gendre, M F; Haverlag, M; Kroesen, G M W

    2010-01-01

    The ignition phase is a critical stage in the operation of gas discharge lamps where the neutral gas enclosed between the electrodes undergoes a transformation from the dielectric state to a conducting phase, eventually enabling the production of light. The phenomena occurring during this phase transition are not fully understood and the related experimental studies are often limited to local optical measurements in environments prone to influencing these transient phenomena. In this work unipolar ignition phenomena at sub-kilovolt levels are investigated in a 3 Torr argon discharge tube. The lamp is placed in a highly controlled environment so as to prevent any bias on the measurements. A fast intensified CCD camera and a specially designed novel electrostatic probe are used simultaneously so as to provide a broad array of measured and computed parameters which are displayed in space-time diagrams for cross comparisons. Experiments show that three distinct phases exist during successful ignitions: upon the application of voltage a first ionization wave starts from the active electrode and propagates in the neutral gas towards the opposite electrode. A local front of high axial E field strength is associated with this process and causes a local ionization to occur, leading to the electrostatic charging of the lamp. Next, a second wave propagates from the ground electrode back towards the active electrode with a higher velocity, and in this process leads to a partial discharging of the lamp. This return stroke draws a homogeneous plasma column which eventually bridges both electrodes at the end of the wave propagation. At this point both electrode sheaths are formed and the common features of a glow discharge are observed. The third phase is an increase in the light intensity of the plasma column until the lamp reaches a steady-state operation. Failed ignitions present only the first phase where the first wave starts its propagation but extinguishes in the lamp

  12. Electrical and optical investigations of transient high pressure discharge phenomena

    International Nuclear Information System (INIS)

    Akishev, Yu.; Karal'nik, V.; Trushkin, N.

    2001-01-01

    The object of our study is the induced formation of streamers (thin current filaments with radius of the order of several hundreds of μm) and spark in steady-state positive corona. It is well known, there are three main current modes (1-diffusive Hermstein glow, 2-streamers, 3-spark) for a centimeters gap positive pin-plane corona in ambient air, which follow in that order with increase of applied voltage. It is common, a critical value of corona current for 1→2-transition equals to 50-70 μA. Streamers start from a tip of pin towards the plane. Streamer mode is characterized by almost periodical splashes in current. In general, both the frequency of streamer occurrence and amplitude of current splashes increase with average corona current from units to tens of kHz and from tens to hundreds of mA, respectively. If the average corona current is in excess of some value, streamers (more precisely, streamer trains) induce periodically the sparks. A quantity of streamers in train inducing a single spark (2→3-transition) is diminished with increase in average corona current

  13. GlowPhones

    DEFF Research Database (Denmark)

    Merritt, Timothy Robert; Nielsen, Christine Linding; Jakobsen, Frederik Lund

    2017-01-01

    Location-based mobile games often utilize built-in sensors for supporting game experiences tied to the physical world, yet the visual user interface remains constrained to the small high-resolution screen. GlowPhones is a location-based mobile social game using low-resolution displays to augment...... the physical space and move the attention away from the mobile screen. Players explore the physical world and collaborate to overcome challenges relying on the screen glow intensity emitted from the phone’s screen and light flash frequency of the camera flash for navigation. Three game stages explore proxemics...

  14. Electrical and spectroscopic characterization of a surgical argon plasma discharge

    International Nuclear Information System (INIS)

    Keller, Sandra; Neugebauer, Alexander; Bibinov, Nikita; Awakowicz, Peter

    2013-01-01

    For electrosurgical procedures, the argon plasma coagulation (APC) discharge is a well-established atmospheric-pressure plasma tool for thermal haemostasis and devitalization of biological tissue. To characterize this plasma source, voltage-current measurements, microphotography, optical emission spectroscopy and numerical simulation are applied. Two discharge modes are established during the operation of the APC plasma source. A short transient spark discharge is ignited within the positive half period of the applied high voltage after a streamer channel connects the APC probe and the counter-electrode. During the second phase, which continues under negative high voltage, a glow discharge is stabilized in the plasma channel.

  15. Feasibility of gas-discharge and optical methods of creating artificial ozone layers of the earth

    International Nuclear Information System (INIS)

    Batanov, G.M.; Kossyi, I.A.; Matveev, A.A.; Silakov, V.P.

    1996-01-01

    Gas-discharge (microwave) and optical (laser) methods of generating large-scale artificial ozone layers in the stratosphere are analyzed. A kinetic model is developed to calculate the plasma-chemical consequences of discharges localized in the stratosphere. Computations and simple estimates indicate that, in order to implement gas-discharge and optical methods, the operating power of ozone-producing sources should be comparable to or even much higher than the present-day power production throughout the world. Consequently, from the engineering and economic standpoints, microwave and laser methods cannot be used to repair large-scale ozone 'holes'

  16. Optical and thermal energy discharge from tritiated solid hydrogen

    International Nuclear Information System (INIS)

    Magnotta, F.; Mapoles, E.R.; Collins, G.W.; Souers, P.C.

    1991-01-01

    The authors are investigating mechanisms of energy storage and release in tritiated solid hydrogens, by a variety of techniques including ESR, NMR and thermal and optical emission. The nuclear decay of a triton in solid hydrogen initiates the conversion of nuclear energy into stored chemical energy by producing unpaired hydrogen atoms which are trapped within the molecular lattice. The ability to store large quantities of atoms in this manner has been demonstrated and can serve as a basis for new forms of high energy density materials. This paper presents preliminary results of a study of the optical emission from solid hydrogen containing tritium over the visible and near infrared (NIR) spectral regions. Specifically, they have studied optical emission from DT and T 2 using CCD, silicon diode and germanium diode arrays. 8 refs., 6 figs

  17. Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source

    International Nuclear Information System (INIS)

    Venkatraman, V.; Kang, S.; Affolderbach, C.; Mileti, G.; Shea, H.

    2014-01-01

    Miniature ( 3 ) vapor-cell based devices using optical pumping of alkali atoms, such as atomic clocks and magnetometers, today mostly employ vertical-cavity surface-emitting lasers as pump light sources. Here, we report on the demonstration of optical pumping in a microfabricated alkali vapor resonance cell using (1) a microfabricated Rb discharge lamp light source, as well as (2) a conventional glass-blown Rb discharge lamp. The microfabricated Rb lamp cell is a dielectric barrier discharge (DBD) light source, having the same inner cell volume of around 40 mm 3 as that of the resonance cell, both filled with suitable buffer gases. A miniature (∼2 cm 3 volume) test setup based on the M z magnetometer interrogation technique was used for observation of optical-radiofrequency double-resonance signals, proving the suitability of the microfabricated discharge lamp to introduce efficient optical pumping. The pumping ability of this light source was found to be comparable to or even better than that of a conventional glass-blown lamp. The reported results indicate that the micro-fabricated DBD discharge lamp has a high potential for the development of a new class of miniature atomic clocks, magnetometers, and quantum sensors

  18. Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source

    Energy Technology Data Exchange (ETDEWEB)

    Venkatraman, V.; Kang, S.; Affolderbach, C.; Mileti, G., E-mail: gaetano.mileti@unine.ch [Laboratoire Temps-Fréquence, University of Neuchâtel, Neuchâtel 2000 (Switzerland); Shea, H. [Microsystems for Space Technologies Laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), Neuchâtel 2002 (Switzerland)

    2014-02-03

    Miniature (optical pumping of alkali atoms, such as atomic clocks and magnetometers, today mostly employ vertical-cavity surface-emitting lasers as pump light sources. Here, we report on the demonstration of optical pumping in a microfabricated alkali vapor resonance cell using (1) a microfabricated Rb discharge lamp light source, as well as (2) a conventional glass-blown Rb discharge lamp. The microfabricated Rb lamp cell is a dielectric barrier discharge (DBD) light source, having the same inner cell volume of around 40 mm{sup 3} as that of the resonance cell, both filled with suitable buffer gases. A miniature (∼2 cm{sup 3} volume) test setup based on the M{sub z} magnetometer interrogation technique was used for observation of optical-radiofrequency double-resonance signals, proving the suitability of the microfabricated discharge lamp to introduce efficient optical pumping. The pumping ability of this light source was found to be comparable to or even better than that of a conventional glass-blown lamp. The reported results indicate that the micro-fabricated DBD discharge lamp has a high potential for the development of a new class of miniature atomic clocks, magnetometers, and quantum sensors.

  19. Gas-dynamic effects in the interaction of a motionless optical pulsating discharge with gas

    International Nuclear Information System (INIS)

    Tishchenko, V N; Grachev, G N; Smirnov, A L; Pavlov, A A; Pavlov, A A; Golubev, M P

    2008-01-01

    The effect of energy removal from the combustion zone of a motionless optical pulsating discharge in the horizontal direction along the axis of a repetitively pulsed laser beam producing the discharge is discovered. The directivity diagram of a hot gas flow is formed during the action of hundreds of pulses. The effect is observed for short pulse durations, when the discharge efficiently generates shock waves. For long pulse durations, the heated gas propagates upward, as in a thermal source. (laser applications and other topics in quantum electronics)

  20. Structure and properties of optical-discharge plasma in CO2-laser beam near target surface

    Science.gov (United States)

    Danshchikov, Ye. V.; Dymshakov, V. A.; Lebedev, F. V.; Ryazanov, A. V.

    1986-05-01

    An experimental study of optical-discharge plasma in a CO2-laser beam at a target surface was made for the purpose of exploring the not yet understood role of this plasma in the laser-target interaction process. Such a plasma was produced by means of a quasi-continuous CO2-laser with an unstable resonator, its power being maintained constant for 1 ms periods. Its radiation was focused on the surfaces of thick and seeding thin Al, Ti, and Ta targets inclined at an approximately 70 deg. angle to the beam, inside a hermetic chamber containing air, argon, or helium under atmospheric pressure. The radiation intensity distribution over the focal plane and the nearest caustic surface in the laser beam was measured along with the plasma parameters, the latter by the methods of spectral analysis and photoelectric recording. The instrumentation for this purpose included an MDR-3 monochromator with an entrance slit, a double electron-optical converter, a memory oscillograph, and an SI-10-30 ribbon lamp as radiation reference standard. The results yielded integral diametral intensity distributions of the emission lines Ti-II (457.2 nm), Ti-I (464 nm), Ar-II (462 nm), radial and axial temperature profiles of optical discharge in metal vapor in surrounding gas, and the radial temperature profile of irradiated metal surface at successive instants of time. The results reveal marked differences between the structures and the properties of optical-discharge plasma in metal vapor and in surrounding gas, optical discharge in the former being characterized by localization within the laser beam and optical discharge in the latter being characterized by a drift away from the target.

  1. The effect of a miniature argon flow rate on the spectral characteristics of a direct current atmospheric pressure glow micro-discharge between an argon microjet and a small sized flowing liquid cathode

    Energy Technology Data Exchange (ETDEWEB)

    Jamroz, Piotr, E-mail: piotr.jamroz@pwr.wroc.pl; Zyrnicki, Wieslaw; Pohl, Pawel

    2012-07-15

    A stable direct current atmospheric pressure glow microdischarge (dc-{mu}APGD) was generated between a miniature Ar flow microjet and a small sized flowing liquid cathode. The microdischarge was operated in the open to air atmosphere. High energy species, including OH, NH, NO, N{sub 2}, H, O and Ar were identified in the emission spectra of this microdischarge. Additionally, atomic lines of metals dissolved in water solutions were easily excited. The near cathode and the near anode zones of the microdischarge were investigated as a function of an Ar flow rate up to 300 sccm. The spectroscopic parameters, i.e., the excitation, the vibrational and the rotational temperatures as well as the electron number density, were determined in the near cathode and the near anode regions of the microdischarge. In the near cathode region, the rotational temperatures obtained for OH (2000-2600 K) and N{sub 2} bands (1600-1950 K) were significantly lower than the excitation temperatures of Ar (7400 K-7800 K) and H (11 000-15 500 K) atoms. Vibrational temperatures of N{sub 2}, OH and NO varied from 3400 to 4000 K, from 2900 to 3400 K and from 2700 to 3000 K, respectively. In the near anode region, rotational temperatures of OH (350-1750 K) and N{sub 2} (400-1350 K) and excitation temperatures of Ar (5200-5500 K) and H (3600-12 600 K) atoms were lower than those measured in the near cathode region. The effect of the introduction of a liquid sample on the microdischarge radiation and spectroscopic parameters was also investigated in the near cathode zone. The electron number density was calculated from the Stark broadening of the H{sub {beta}} line and equals to (0.25-1.1) Multiplication-Sign 10{sup 15} cm{sup -3} and (0.68-1.2) Multiplication-Sign 10{sup 15} cm{sup -3} in the near cathode and the near anode zones, respectively. The intensity of the Na I emission line and the signal to background ratio (SBR) of this line were investigated in both zones to evaluate the excitation

  2. The effect of a miniature argon flow rate on the spectral characteristics of a direct current atmospheric pressure glow micro-discharge between an argon microjet and a small sized flowing liquid cathode

    International Nuclear Information System (INIS)

    Jamróz, Piotr; Żyrnicki, Wiesław; Pohl, Paweł

    2012-01-01

    A stable direct current atmospheric pressure glow microdischarge (dc-μAPGD) was generated between a miniature Ar flow microjet and a small sized flowing liquid cathode. The microdischarge was operated in the open to air atmosphere. High energy species, including OH, NH, NO, N 2 , H, O and Ar were identified in the emission spectra of this microdischarge. Additionally, atomic lines of metals dissolved in water solutions were easily excited. The near cathode and the near anode zones of the microdischarge were investigated as a function of an Ar flow rate up to 300 sccm. The spectroscopic parameters, i.e., the excitation, the vibrational and the rotational temperatures as well as the electron number density, were determined in the near cathode and the near anode regions of the microdischarge. In the near cathode region, the rotational temperatures obtained for OH (2000–2600 K) and N 2 bands (1600–1950 K) were significantly lower than the excitation temperatures of Ar (7400 K–7800 K) and H (11 000–15 500 K) atoms. Vibrational temperatures of N 2 , OH and NO varied from 3400 to 4000 K, from 2900 to 3400 K and from 2700 to 3000 K, respectively. In the near anode region, rotational temperatures of OH (350–1750 K) and N 2 (400–1350 K) and excitation temperatures of Ar (5200–5500 K) and H (3600–12 600 K) atoms were lower than those measured in the near cathode region. The effect of the introduction of a liquid sample on the microdischarge radiation and spectroscopic parameters was also investigated in the near cathode zone. The electron number density was calculated from the Stark broadening of the H β line and equals to (0.25–1.1) × 10 15 cm −3 and (0.68–1.2) × 10 15 cm −3 in the near cathode and the near anode zones, respectively. The intensity of the Na I emission line and the signal to background ratio (SBR) of this line were investigated in both zones to evaluate the excitation properties of the developed excitation microsource. The limit of

  3. Electrodeless-discharge-vapor-lamp-based Faraday anomalous-dispersion optical filter.

    Science.gov (United States)

    Sun, Qinqing; Zhuang, Wei; Liu, Zhiwen; Chen, Jingbiao

    2011-12-01

    We report an excited-state Faraday anomalous-dispersion optical filter operating on the rubidium 5P(3/2)-5D(5/2) transition (775.9 nm in vacuum) without the use of a pump laser. An electrodeless discharge vapor lamp is employed to replace the Rb vapor cell in a traditional Faraday anomalous-dispersion optical filter system. Atoms can be excited by power rather than a complex frequency-locked pump laser. A proof-of-concept experimental demonstration with a maximum transmission of 1.9% and a filter bandwidth of 650 MHz is presented. © 2011 Optical Society of America

  4. On the formation mechanisms of the diffuse atmospheric pressure dielectric barrier discharge in CVD processes of thin silica-like films

    International Nuclear Information System (INIS)

    Starostin, S A; Premkumar, P Antony; Creatore, M; Van Veldhuizen, E M; Van de Sanden, M C M; De Vries, H; Paffen, R M J

    2009-01-01

    Pathways of formation and temporal evolution of the diffuse dielectric barrier discharge at atmospheric pressure were experimentally studied in this work by means of optical (fast imaging camera) and electrical diagnostics. The chosen model system is relevant for applications of plasma-enhanced chemical vapor deposition of thin silica-like film on the polymeric substrate, from cost-efficient gas mixtures of Ar/N 2 /O 2 /hexamethyldisiloxane. It was found that the discharge can gradually experience the phases of homogeneous low current Townsend-like mode, local Townsend to glow transition and expanding high current density (∼0.7 A cm -2 ) glow-like mode. While the glow-like current spot occupies momentarily only a small part of the electrode area, its expanding behavior provides uniform treatment of the whole substrate surface. Alternatively, it was observed that a visually uniform discharge can be formed by the numerous microdischarges overlapping over the large electrode area.

  5. Optical and structural properties of colloidal zirconia nanoparticles prepared by arc discharge in liquid

    Science.gov (United States)

    Peymani forooshani, Reza; Poursalehi, Reza; Yourdkhani, Amin

    2018-01-01

    Zirconia is one of the important ceramic materials with unique properties such as high melting point, high ionic conductivity, high mechanical properties and low thermal conductivity. Therefore, zirconia is one of the useful materials in refractories, thermal barriers, cutting tools, oxygen sensors electrolytes, catalysis, catalyst supports and solid oxide fuel cells. Recently, direct current (DC) arc discharge is extensively employed to synthesis of metal oxide nanostructures in liquid environments. The aim of this work is the synthesis of colloidal zirconia nanoparticles by DC arc discharge method in water as a medium. Arc discharge was ignited between two pure zirconium electrodes in water. Optical and structural properties of prepared colloidal nanoparticles were investigated. Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and UV-visible spectroscopy, were employed for characterization of particle size, morphology, crystal structure and optical properties, respectively. SEM images demonstrate that the nanoparticles are spherical in shape with an average size lower than 38 nm. The XRD patterns of the nanoparticles were consistent with tetragonal and monoclinic zirconia crystal structures. The optical transmission spectra of the colloidal solution show optical characteristic of zirconia nanoparticles as a wide band gap semiconductor with no absorption peak in visible wavelength with the considerable amount of oxygen deficiency. Oxidation of colloidal nanoparticles in water could be explained via reaction with either dissociated oxygen from water in hot plasma region or with dissolved oxygen in water. The results provide a simple and flexible method for preparation of zirconia nanoparticles with a capability of mass production without environmental footprints.

  6. Study of short atmospheric pressure dc glow microdischarge in air

    Science.gov (United States)

    Kudryavtsev, Anatoly; Bogdanov, Eugene; Chirtsov, Alexander; Emelin, Sergey

    2011-10-01

    The results of experiments and simulations of short (without positive column) atmospheric pressure dc glow discharge in air are presented. We used metal steel electrodes with a gap of 5-100 microns. The experimental voltage-current characteristic's (VAC) have a constant or slightly increasing form at low gap. The most stable microdischarges were burning with a flat cathode and rounded anode, when the length of the discharge is automatically established near the minimum of the Paschen curve by changing their binding on the anode. In this case microdischarge was stable and it had growing VAC. For simulations we used 2D fluid model with kinetic description of electrons. We solved the balance equations for the vibrationally- and the electronically-excited states of a nitrogen and oxygen molecules; nitrogen and oxygen atoms; ozone molecule; and different nitrogen and oxygen ions with different plasmochemical reactions between them. Simulations predicted the main regions of the dc glow discharges including cathode and anode sheath and plasma of negative glow, Faraday dark space and transition region. Gas heating plays an important role in shaping the discharge profiles. The results of experiments and simulations of short (without positive column) atmospheric pressure dc glow discharge in air are presented. We used metal steel electrodes with a gap of 5-100 microns. The experimental voltage-current characteristic's (VAC) have a constant or slightly increasing form at low gap. The most stable microdischarges were burning with a flat cathode and rounded anode, when the length of the discharge is automatically established near the minimum of the Paschen curve by changing their binding on the anode. In this case microdischarge was stable and it had growing VAC. For simulations we used 2D fluid model with kinetic description of electrons. We solved the balance equations for the vibrationally- and the electronically-excited states of a nitrogen and oxygen molecules; nitrogen

  7. The production and extraction of polarized electrons from an optically pumped helium discharge

    International Nuclear Information System (INIS)

    Vandiver, R.J.; Schearer, L.D.; Gay, T.J.

    1992-01-01

    Polarized electrons are produced from interactions involving nearly 100% polarized helium 2 3 S 1 metastable atoms in a weak electrical discharge. The high metastable polarizations are obtained through the use of recently developed, high-power lasers tunable to the relevant helium transitions near 1083 nm and the development of a crossed beam pumping technique. The dominant interactions involving the 2 3 S 1 atoms and electrons are spin preserving; hence the electrons of the discharge attain a high polarization. The authors have extracted a well collimated electron beam with over 20 μA of current from the discharge. An optical polarimeter will be used to determine the polarization of the extracted electrons

  8. In situ dc oxygen‐discharge cleaning system for optical elements

    International Nuclear Information System (INIS)

    Koide, Tsuneharu; Shidara, Tetsuo; Tanaka, Kenichiro; Yagishita, Akira; Sato, Shigeru

    1989-01-01

    In situ dc oxygen‐discharge cleaning arrangements have been developed at the Photon Factory for the removal of carbon contamination from optical surfaces. A high cleaning rate could be achieved by producing an oxygen plasma close to the optical elements with special care taken to avoid any harmful effects from the discharge; contaminant carbon was completely removed within a few hours, at most. This short exposure time and the use of dry oxygen gas resulted in a restoration of the original ultrahigh vacuum without a bakeout. Results with a Seya‐Namioka beamline for gas‐phase experiments showed a flux enhancement amounting to a factor of 50, and results with a grasshopper beamline showed a nearly complete recovery of the light intensity, even at the carbon K edge

  9. In situ dc oxygen-discharge cleaning system for optical elements

    International Nuclear Information System (INIS)

    Koide, T.; Shidara, T.; Tanaka, K.; Yagishita, A.; Sato, S.

    1989-01-01

    In situ dc oxygen-discharge cleaning arrangements have been developed at the Photon Factory for the removal of carbon contamination from optical surfaces. A high cleaning rate could be achieved by producing an oxygen plasma close to the optical elements with special care taken to avoid any harmful effects from the discharge; contaminant carbon was completely removed within a few hours, at most. This short exposure time and the use of dry oxygen gas resulted in a restoration of the original ultrahigh vacuum without a bakeout. Results with a Seya-Namioka beamline for gas-phase experiments showed a flux enhancement amounting to a factor of 50, and results with a grasshopper beamline showed a nearly complete recovery of the light intensity, even at the carbon K edge

  10. [Study on formation process of honeycomb pattern in dielectric barrier discharge by optical emission spectrum].

    Science.gov (United States)

    Dong, Li-Fang; Zhu, Ping; Yang, Jing; Zhang, Yu

    2014-04-01

    The authors report on the first investigation of the variations in the plasma parameters in the formation process of the honeycomb pattern in a dielectric barrier discharge by optical emission spectrum in argon and air mixture. The discharge undergoes hexagonal lattice, concentric spot-ring pattern and honeycomb pattern with the applied voltage increasing. The molecular vibration temperature, electron excitation temperature and electronic density of the three kinds of patterns were investigated by the emission spectra of nitrogen band of second positive system (C3pi(u) --> B3 pi(g)), the relative intensity ratio method of spectral lines of Ar I 763.51 nm (2P(6) --> 1S(5)) and Ar I 772.42 nm (2P(2) -->1S(3)) and the broadening of spectral line 696.5 nm respectively. It was found that the molecular vibration temperature and electron excitation temperature of the honeycomb pattern are higher than those of the hexagonal lattice, but the electron density of the former is lower than that of the latter. The discharge powers of the patterns were also measured with the capacitance method. The discharge power of the honeycomb pattern is much higher than that of the hexagonal lattice. These results are of great importance to the formation mechanism of the patterns in dielectric barrier discharge.

  11. The Diagnosis of Plasma Parameters in Surface Alloying Technique by Optical Emission Spectrometry

    International Nuclear Information System (INIS)

    Fu Yabo; Zhang Yuefei; Chen Qiang; Zhang Guangqiu; Gao Yuan; Wang Jianzhong; Kui Xiaoyun

    2006-01-01

    Electron density (Ne) in a glow discharge plasma for the surface alloying technique is diagnosed by optical emission spectrometry (OES). With CH 4 as the feeding gas, Ne is obtained by comparing the Hβ spectrum according to the Stark broadening effect. It is noticed that Ne varies with the working pressures (30 Pa to 70 Pa) and cathode voltages (500 V to 1000 V), respectively. Due to an abnormal glow discharge, Ne is between 1.71x10 15 /cm 3 to 6.64x10 15 /cm 3 and increases rapidly with working gas pressures and cathode voltages. The results show that OES is a useful method to measure the plasma parameters in a surface alloying glow discharge plasma

  12. An optical sensors for monitoring SF6 dissociation in a corona discharge

    International Nuclear Information System (INIS)

    Irawan, R.; Scelsi, G.B.; Woolsey, G.A.

    1999-01-01

    Sulphur hexafluoride (SF 6 ) is a chemically inert gas (Schumb, 1947) and has high dielectric strength, 3 times greater than air (Morrison and Robins, 1994). In high voltage systems, it is used both as a dielectric and an arc-quenching medium. An electrical breakdown event such as a partial discharge (corona) or arc will dissociate SF 6 into sulphur fluorides, sulphur and fluorine. In a contaminant-free environment, the dissociation products recombine back to SF 6 after extinction of the electrical discharge. Otherwise, some of the products will react with contaminants such as water vapour and oxygen, and with the metal surfaces and electrodes of the discharge chamber, to produce by-products including gaseous sulphur oxyfluorides and solid by-products (Van Brunt, 1985; Griffin et al, 1990 and Vukovic, 1997). As a consequence, a reduction in SF 6 concentration takes place, and the insulating efficiency of the system is degraded. If the SF 6 is not renewed, failure of the high voltage system is likely to eventually occur. One method of monitoring a system is to look for the presence of partial discharges, using techniques such as ultrasonic wave detection (Auckland et al, 1996) or fluorescent plastic fibre (Kurosawa et al., 1997). More directly, the integrity of the SF 6 may be examined using techniques such as mass spectrometry, gas chromatography-mass spectrometry and Fourier Transform Infra-Red Spectroscopy. Such techniques, however, are bulky and require gas samples to be extracted, and so they are unsuited to field use. Since SF 6 insulating systems involve high voltages and a high level of electromagnetic interference, direct in-situ optical monitoring appears to provide the best approach. This paper describes the development of such an optical sensing technique, specifically for continuous monitoring of SF 6 degradation in partial or corona discharges

  13. Electric field measurement in microwave discharge ion thruster with electro-optic probe.

    Science.gov (United States)

    Ise, Toshiyuki; Tsukizaki, Ryudo; Togo, Hiroyoshi; Koizumi, Hiroyuki; Kuninaka, Hitoshi

    2012-12-01

    In order to understand the internal phenomena in a microwave discharge ion thruster, it is important to measure the distribution of the microwave electric field inside the discharge chamber, which is directly related to the plasma production. In this study, we proposed a novel method of measuring a microwave electric field with an electro-optic (EO) probe based on the Pockels effect. The probe, including a cooling system, contains no metal and can be accessed in the discharge chamber with less disruption to the microwave distribution. This method enables measurement of the electric field profile under ion beam acceleration. We first verified the measurement with the EO probe by a comparison with a finite-difference time domain numerical simulation of the microwave electric field in atmosphere. Second, we showed that the deviations of the reflected microwave power and the beam current were less than 8% due to inserting the EO probe into the ion thruster under ion beam acceleration. Finally, we successfully demonstrated the measurement of the electric-field profile in the ion thruster under ion beam acceleration. These measurements show that the electric field distribution in the thruster dramatically changes in the ion thruster under ion beam acceleration as the propellant mass flow rate increases. These results indicate that this new method using an EO probe can provide a useful guide for improving the propulsion of microwave discharge ion thrusters.

  14. Electron density measurement in gas discharge plasmas by optical and acoustic methods

    International Nuclear Information System (INIS)

    Biagioni, A.; Anania, M.P.; Bellaveglia, M.; Chiadroni, E.; Giovenale, D. Di; Pirro, G. Di; Ferrario, M.; Pompili, R.; Shpakov, V.; Vaccarezza, C.; Villa, F.; Cianchi, A.; Filippi, F.; Mostacci, A.; Zigler, A.

    2016-01-01

    Plasma density represents a very important parameter for both laser wakefield and plasma wakefield acceleration, which use a gas-filled capillary plasma source. Several techniques can be used to measure the plasma density within a capillary discharge, which are mainly based on optical diagnostic methods, as for example the well-known spectroscopic method using the Stark broadening effect. In this work, we introduce a preliminary study on an alternative way to detect the plasma density, based on the shock waves produced by gas discharge in a capillary. Firstly, the measurements of the acoustic spectral content relative to the laser-induced plasmas by a solid target allowed us to understand the main properties of the acoustic waves produced during this kind of plasma generation; afterwards, we have extended such acoustic technique to the capillary plasma source in order to calibrate it by comparison with the stark broadening method.

  15. Plasma Glow Discharge as a Tool for Surface Modification of Catalytic Solid Oxides: A Case Study of La0.6Sr0.4Co0.2Fe0.8O3−δ Perovskite

    Directory of Open Access Journals (Sweden)

    Yanxiang Zhang

    2016-09-01

    Full Text Available Performance of solid oxide fuel cells (SOFCs is hindered by the sluggish catalytic kinetics on the surfaces of cathode materials. It has recently been reported that improved electrochemical activity of perovskite oxides can be obtained with the cations or the oxides of some metallic elements at the surface. Here, we used a cost-effective plasma glow charge method as a generic tool to deposit nano-size metallic particles onto the surface of SOFC materials. Ni nano-scale patterns were successfully coated on the La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF surface. The microstructure could be well controlled. The kinetics of oxygen exchange on the modified LSCF surface was promoted significantly, confirmed by electrical conductivity relaxation (ECR measurement.

  16. A Study of Electron Decay in Nitrogen Time After-glow

    International Nuclear Information System (INIS)

    Veis, P.; Coitout, H.; Magne, L.; Cernogora, G.

    1999-01-01

    This paper deals with electron density measurements in nitrogen time after-glow using hyper frequency resonant cavity. The studied pressures are from the range 9-530 Pa and discharge currents from 20 mA up to 500 mA. Electrons decreases up to the time of 1,4 ms in after-glow depending on pressure, pulse current and pulse duration (Authors)

  17. Clearance of short circuited ion optics electrodes by capacitive discharge. [in ion thrusters

    Science.gov (United States)

    Poeschel, R. L.

    1976-01-01

    The ion optics electrodes of low specific impulse (3000 sec) mercury electron bombardment ion thrusters are vulnerable to short circuits by virtue of their relatively small interelectrode spacing (0.5 mm). Metallic flakes from backsputtered deposits are the most probable cause of such 'shorts' and 'typical' flakes have been simulated here using refractory wire that has a representative, but controllable, cross section. Shorting wires can be removed by capacitive discharge without significant damage to the electrodes. This paper describes an evaluation of 'short' removal versus electrode damage for several combinations of capacitor voltage, stored energy, and short circuit conditions.

  18. Optical fiber sensor of partial discharges in High Voltage DC experiments

    Science.gov (United States)

    Búa-Núñez, I.; Azcárraga-Ramos, C. G.; Posada-Román, J. E.; Garcia-Souto, J. A.

    2014-05-01

    A setup simulating High Voltage DC (HVDC) transformers barriers was developed to demonstrate the effectiveness of an optical fiber (OF) sensor in detecting partial discharges (PD) under these peculiar conditions. Different PD detection techniques were compared: electrical methods, and acoustic methods. Standard piezoelectric sensors (R15i-AST) and the above mentioned OF sensors were used for acoustic detection. The OF sensor was able to detect PD acoustically with a sensitivity better than the other detection methods. The multichannel instrumentation system was tested in real HVDC conditions with the aim of analyzing the behavior of the insulation (mineral oil/pressboard).

  19. Characterization of a direct dc-excited discharge in water by optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bruggeman, Peter; Leys, Christophe [Department of Applied Physics, Ghent University, Jozef Plateaustraat 22, B-9000 Ghent (Belgium); Schram, Daan [Department of Applied Physics, Technische Universiteit Eindhoven, PO Box 513, 5600 MB Eindhoven (Netherlands); Gonzalez, Manuel A [Departamento de Fisica Aplicada, Universidad de Valladolid, 47011 Valladolid (Spain); Rego, Robby [Flemish Institute of Technological Research, VITO Materials, Boeretang 200, B-2400 Mol (Belgium); Kong, Michael G [Department of Electronic and Electrical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom)], E-mail: peter.bruggeman@ugent.be

    2009-05-01

    Dc-excited discharges generated in water at the tip of a tungsten wire which is located at the orifice of a quartz capillary are investigated by time-averaged optical emission spectroscopy. Two distinctive discharge modes are observed. For small conductivities of the liquid the discharge is a streamer-like discharge in the liquid itself (liquid mode). For conductivities above typically 45 {mu}S cm{sup -1} a large vapour bubble is formed and a streamer discharge in this vapour bubble is observed (bubble mode). Plasma temperatures and electron densities are investigated for both modes. The gas temperature is estimated from the rotational temperature of N{sub 2}(C-B) and is 1600 {+-} 200 K for the bubble mode and 1900 {+-} 200 K for the liquid mode. The rotational temperature of OH(A-X) is up to 2 times larger and cannot be used as an estimate for the gas temperature. The rotational population distribution of OH(A), {nu} = 0 is also non-Boltzmann with a large overpopulation of high rotational states. This discrepancy in rotational temperatures is discussed in detail. Electron densities are obtained from the Stark broadening of the hydrogen Balmer beta line. The electron densities in the liquid mode are of the order of 10{sup 21} m{sup -3}. In the bubble mode electron densities are significantly smaller: (3-4) x 10{sup 20} m{sup -3}. These values are compared with the Stark broadening of the hydrogen alpha and gamma lines and with electron densities obtained from current density measurements. The chemical reactivities of the bubble and liquid modes are compared by means of the hydrogen peroxide production rate.

  20. Characterization of a direct dc-excited discharge in water by optical emission spectroscopy

    International Nuclear Information System (INIS)

    Bruggeman, Peter; Leys, Christophe; Schram, Daan; Gonzalez, Manuel A; Rego, Robby; Kong, Michael G

    2009-01-01

    Dc-excited discharges generated in water at the tip of a tungsten wire which is located at the orifice of a quartz capillary are investigated by time-averaged optical emission spectroscopy. Two distinctive discharge modes are observed. For small conductivities of the liquid the discharge is a streamer-like discharge in the liquid itself (liquid mode). For conductivities above typically 45 μS cm -1 a large vapour bubble is formed and a streamer discharge in this vapour bubble is observed (bubble mode). Plasma temperatures and electron densities are investigated for both modes. The gas temperature is estimated from the rotational temperature of N 2 (C-B) and is 1600 ± 200 K for the bubble mode and 1900 ± 200 K for the liquid mode. The rotational temperature of OH(A-X) is up to 2 times larger and cannot be used as an estimate for the gas temperature. The rotational population distribution of OH(A), ν = 0 is also non-Boltzmann with a large overpopulation of high rotational states. This discrepancy in rotational temperatures is discussed in detail. Electron densities are obtained from the Stark broadening of the hydrogen Balmer beta line. The electron densities in the liquid mode are of the order of 10 21 m -3 . In the bubble mode electron densities are significantly smaller: (3-4) x 10 20 m -3 . These values are compared with the Stark broadening of the hydrogen alpha and gamma lines and with electron densities obtained from current density measurements. The chemical reactivities of the bubble and liquid modes are compared by means of the hydrogen peroxide production rate.

  1. An algorithm for unified analysis on the thermoluminescence glow curve

    International Nuclear Information System (INIS)

    Chung, K.S.; Park, C.Y.; Lee, J.I.; Kim, J.L.

    2014-01-01

    An algorithm was developed to integrally handle excitation by radiation, relaxation and luminescence by thermal or optical stimulation in thermoluminescence (TL) and optically stimulated luminescence (OSL) processes. This algorithm reflects the mutual interaction between traps through a conduction band. Electrons and holes are created by radiation in the beginning, and these electrons move to the trap through the conduction band. These holes move to the recombination center through a valence band. The ratio of the electrons allocated to each trap differs with the recombination probability and these values also relevant to the process of luminescence. Accordingly, the glow curve can be interpreted by taking the rate of electron–hole pairs created by ionizing radiation as a unique initial condition. This method differs from the conventional method of interpreting the measured glow curve with the initial electron concentration allocated to each trap at the end of irradiation. A program using the Visual Studio's C# subsystem was made to realize such a developed algorithm. To verify this algorithm it was applied to LiF:Mg,Cu,Si. The TL glow curve was deconvoluted with a model of five traps, one deep trap and one recombination center (RC). - Highlights: • TL glow curve deconvolution employing interacting model. • Simulation both irradiation and TL readout stages for various dose level. • Application in the identification TL kinetics of LiF:Mg,Cu,Si TLD

  2. Effects of corona discharge treatment on some properties of wool ...

    African Journals Online (AJOL)

    Yomi

    2011-12-21

    Dec 21, 2011 ... Corona discharge after operation worsted water absorption property increased and the ... finally conditioned with atmospheric air (20°C, relative humidity ... For corona treatment, a glow discharge generator was used with a.

  3. Discharge estimation in arid areas with the help of optical satellite data

    Science.gov (United States)

    Mett, M.; Aufleger, M.

    2009-04-01

    The MENA region is facing severe water scarcity. Overexploitation of groundwater resources leads to an ongoing drawdown of the water tables, salinisation and desertification of vast areas. To make matters worse enormous birth-rates, economic growth and refugees from conflict areas let the need for water explode. In the context of climate change this situation will even worsen and armed conflicts are within the bounds of possibility. To ease water scarcity many innovative techniques like artificial groundwater recharge are being developed or already state of the art. But missing hydrological information (for instance discharge data) often prevents design and efficient operation of such measures. Especially in poor countries hydrological measuring devices like gage stations are often missing, in a bad status or professionals of the water sector are absent. This leads to the paradox situation that in many arid regions water resources are indeed available but they cannot be utilised because they are not known. Nowadays different approaches are being designed to obtain hydrological information from perennial river systems with the help of satellite techniques. Mostly they are based on hydraulic parameters like river dimensions, roughness and water levels which can be derived from satellite data. By using conventional flow formulas and additional field investigations the discharge can be estimated. Another methodology derived information about maximum flow depth and flow width from optical sensors of high resolution to calculate discharge of the rivers whilst the flood. Attempts to derive discharge information from structural components of the river and fluviomorphologic changes due to changing flow regimes are in the focus of recent research. One attempt used Synthetic Aperture Radar (SAR) data to estimate discharge in braided river systems. Other attempts used airborne SAR imagery to obtain information about sinuosity and total river width of perennial braided river

  4. [Study on plasma temperature of a large area surface discharge by optical emission spectrum].

    Science.gov (United States)

    Dong, Li-Fang; Tong, Guo-Liang; Zhang, Yu; Zhou, Bin

    2014-04-01

    A large area surface discharge was realized in air/argon gas mixture by designing a discharge device with water electrodes. By using optical emission spectrum, the variations of the molecular vibrational temperature, the mean energy of electron, and the electronic excitation temperature as a function of the gas pressure were studied. The nitrogen molecular vibrational temperature was calculated according to the emission line of the second positive band system of the nitrogen molecule (C3 pi(u) --> B 3 pi(g)). The electronic excitation temperature was obtained by using the intensity ratio of Ar I 763.51 nm (2P(6) --> 1S(5)) to Ar I 772.42 nm (2P(2) --> 1S(3)). The changes in the mean energy of electron were studied by the relative intensity ratio of the nitrogen molecular ion 391.4 nm to nitrogen 337.1 nm. It was found that the intensity of emission spectral line increases with the increase in the gas pressure, meanwhile, the outline and the ratios of different spectral lines intensity also change. The molecular vibrational temperature, the mean energy of electron, and the electronic excitation temperature decrease as the gas pressure increases from 0.75 x 10(5) Pa to 1 x 10(5) Pa.

  5. The Effects of Lamp Spectral Distribution on Sky Glow over Observatories

    Science.gov (United States)

    2015-01-01

    overhead sky glow as a function of distance up to 300 km, from a variety of lamp types, including common gas discharge lamps and several types of LED...distance up to 300 km, from a variety of lamp types, in- cluding common gas discharge lamps and several types of LED lamps . We conclude for both...MAR 2015 2. REPORT TYPE 3. DATES COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE The Effects of Lamp Spectral Distribution on Sky Glow

  6. Oxygen negative glow: reactive species and emissivity

    International Nuclear Information System (INIS)

    Sahli, Khaled

    1991-01-01

    This research thesis addresses the study of a specific type of oxygen plasma created by electron beams (1 keV, 20 mA/cm"2), negative glow of a luminescent discharge in abnormal regime. The objective is to test the qualities of this plasma as source of two 'active' species of oxygen (singlet molecular oxygen and atomic oxygen) which are useful in applications. The experiment mainly bears on the use of VUV (120 to 150 nm) absorption spectroscopy measurements of concentrations of these both species, and on the recording of plasma emissivity space profiles in the visible region (450 to 850 nm). It appears that low concentrations of singlet oxygen definitely exclude this type of discharge for iodine laser applications. On the contrary, concentrations measured for atomic oxygen show it is a good candidate for the oxidation of large surfaces by sheets of beams. The satisfying comparison of emissivity results with a published model confirm the prevailing role of fast electrons, and gives evidence of an important effect of temperature: temperature can reach 1000 K, and this is in agreement with the presented measurement [fr

  7. Self-stabilized discharge filament in plane-parallel barrier discharge configuration: formation, breakdown mechanism, and memory effects

    Science.gov (United States)

    Tschiersch, R.; Nemschokmichal, S.; Bogaczyk, M.; Meichsner, J.

    2017-10-01

    Single self-stabilized discharge filaments were investigated in the plane-parallel electrode configuration. The barrier discharge was operated inside a gap of 3 mm shielded by glass plates to both electrodes, using helium-nitrogen mixtures and a square-wave feeding voltage at a frequency of 2 kHz. The combined application of electrical measurements, ICCD camera imaging, optical emission spectroscopy and surface charge diagnostics via the electro-optic Pockels effect allowed the correlation of the discharge development in the volume and on the dielectric surfaces. The formation criteria and existence regimes were found by systematic variation of the nitrogen admixture to helium, the total pressure and the feeding voltage amplitude. Single self-stabilized discharge filaments can be operated over a wide parameter range, foremost, by significant reduction of the voltage amplitude after the operation in the microdischarge regime. Here, the outstanding importance of the surface charge memory effect on the long-term stability was pointed out by the recalculated spatio-temporally resolved gap voltage. The optical emission revealed discharge characteristics that are partially reminiscent of both the glow-like barrier discharge and the microdischarge regime, such as a Townsend pre-phase, a fast cathode-directed ionization front during the breakdown and radially propagating surface discharges during the afterglow.

  8. [Study on A White-Eye Pattern in Dielectric Barrier Discharge by Optical Emission Spectrum].

    Science.gov (United States)

    Zhu, Ping; Dong, Li-fang; Yang, Jing; Zhang, Yu; Zhang, Chao

    2015-06-01

    The white-eye pattern was firstly observed and investigated in a dielectric barrier discharge system in the mixture of argon and air whose content can be varied whenever necessary, and the study shows that the white-eye cell is an interleaving of three different hexagonal sub-structures: the center spot, the halo, and the ambient spots. The white-eye pattern is observed at a lower applied voltage. In this experiment, the heat capacity of water is high so that the water in water electrode is good at absorbing heat. In the process of pattern discharging the gas gap didn't increase its temperature, and the discharging phenomenon of this pattern has not changed. The temperature of the water electrodes almost keeps unchanged during the whole experiment, which is advantageous for the long-term stable measurement. Pictures recorded by ordinary camera with long exposure time in the same argon content condition show that the center spot, the halo, and the ambient spots og the white-eye pattern have different brightness, which may prove that their plasma states are different. And, it is worth noting that there are obvious differences of brightness not only on the center spot, the halo, and the ambient spots at the same pressure but also at the different pressure, which shows that its plasma state also changed with the variation of the pressure. Given this, in this experiment plasma temperatures of the central spot, halo, and ambient spots in a white-eye pattern at different gas pressure were studied by using optical emission spectra. The molecular vibration temperature is investigated by the emission spectra of nitrogen band of second positive system ( C3Πu --> B3Πg ). The electron excitation temperature is researched by the relative intensity ratio method of spectral lines of Ar I 763. 51 nm (2P6 --> 1S5) and Ar I 772. 42 nm (2P2 --> 1S3). The electronic density is investigated by the broadening of spectral line 696.5 nm. Through the analysis of experimental results, it

  9. Dissolution glow curve in LLD

    International Nuclear Information System (INIS)

    Haverkamp, U.; Wiezorek, C.; Poetter, R.

    1990-01-01

    Lyoluminescence dosimetry is based upon light emission during dissolution of previously irradiated dosimetric materials. The lyoluminescence signal is expressed in the dissolution glow curve. These curves begin, depending on the dissolution system, with a high peak followed by an exponentially decreasing intensity. System parameters that influence the graph of the dissolution glow curve, are, for example, injection speed, temperature and pH value of the solution and the design of the dissolution cell. The initial peak does not significantly correlate with the absorbed dose, it is mainly an effect of the injection. The decay of the curve consists of two exponential components: one fast and one slow. The components depend on the absorbed dose and the dosimetric materials used. In particular, the slow component correlates with the absorbed dose. In contrast to the fast component the argument of the exponential function of the slow component is independent of the dosimetric materials investigated: trehalose, glucose and mannitol. The maximum value, following the peak of the curve, and the integral light output are a measure of the absorbed dose. The reason for the different light outputs of various dosimetric materials after irradiation with the same dose is the differing solubility. The character of the dissolution glow curves is the same following irradiation with photons, electrons or neutrons. (author)

  10. Surface hardening of optic materials by deposition of diamond like carbon coatings from separated plasma of arc discharge

    Science.gov (United States)

    Osipkov, A. S.; Bashkov, V. M.; Belyaeva, A. O.; Stepanov, R.; Mironov, Y. M.; Galinovsky, A. L.

    2015-02-01

    This article considers the issue of strengthening of optic materials used in the IR spectrum by deposition of diamond like carbon coatings from separated plasma arc discharge. The report shows results of tests of bare and strengthened optical materials such as BaF2, MgF2, Si, Ge, including the testing of their strength and spectral characteristics. Results for the determination of optical constants for the DLC coatings deposited on substrates of Ge and Si, by using separated plasma, are also presented. Investigations showed that surface hardening of optical materials operable in the IR range, by the deposition of diamond like carbon coating onto their surface, according to this technology, considerably improves operational properties and preserves or improves their optic properties.

  11. Simulation Study of an Extended Density DC Glow Toroidal Plasma Source

    International Nuclear Information System (INIS)

    Granda-Gutierrez, E. E.; Piedad-Beneitez, A. de la; Lopez-Callejas, R.; Godoy-Cabrera, O. G.; Benitez-Read, J. S.; Pacheco-Sotelo, J. O.; Pena-Eguiluz, R.; Mercado-Cabrera, A.; Valencia A, R.; Barocio, S. R.

    2006-01-01

    Conventional wisdom assigns the DC glow discharge regime to plasma currents below ∼500 mA values, beyond which the discharge falls into the anomalous glow and the turbulent arc regimes. However, we have found evidence that, during toroidal discharges, this barrier can be ostensibly extended up to 800 mA. Thus, a computer simulation has been applied to the evolution of the main electrical characteristics of such a glow discharge plasma in a toroidal vessel in order to design and construct a respective voltage/current controlled source. This should be able to generate a DC plasma in the glow regime with which currents in the range 10-3-100 A can be experimented and 109-1010 cm-3 plasma densities can be achieved to PIII optimization purposes. The plasma is modelled as a voltage-controlled current source able to be turned on whenever the breakdown voltage is reached across the gap between the anode and the vessel wall. The simulation outcome fits well our experimental measurements showing that the plasma current obeys power laws that are dependent on the power current and other control variables such as the gas pressure

  12. Numerical analysis of thermoluminescence glow curves

    International Nuclear Information System (INIS)

    Gomez Ros, J. M.; Delgado, A.

    1989-01-01

    This report presents a method for the numerical analysis of complex thermoluminescence glow curves resolving the individual glow peak components. The method employs first order kinetics analytical expressions and is based In a Marquart-Levenberg minimization procedure. A simplified version of this method for thermoluminescence dosimetry (TLD) is also described and specifically developed to operate whit Lithium Fluoride TLD-100. (Author). 36 refs

  13. Fabrication of Annealed Gold Nanostructures on Pre-Treated Glow-Discharge Cleaned Glasses and Their Used for Localized Surface Plasmon Resonance (LSPR and Surface Enhanced Raman Spectroscopy (SERS Detection of Adsorbed (Biomolecules

    Directory of Open Access Journals (Sweden)

    Rodica Elena Ionescu

    2017-01-01

    Full Text Available Metallic nanoparticles are considered as active supports in the development of specific chemical or biological biosensors. Well-organized nanoparticles can be prepared either through expensive (e.g., electron beam lithography or inexpensive (e.g., thermal synthesis approaches where different shapes of nanoparticles are easily obtained over large solid surfaces. Herein, the authors propose a low-cost thermal synthesis of active plasmonic nanostructures on thin gold layers modified glass supports after 1 h holding on a hot plate (~350 °C. The resulted annealed nanoparticles proved a good reproducibility of localized surface plasmon resonance (LSPR and surface enhanced Raman spectroscopy (SERS optical responses and where used for the detection of low concentrations of two model (biochemical molecules, namely the human cytochrome b5 (Cyt-b5 and trans-1,2-bis(4-pyridylethylene (BPE.

  14. Optical and EUV studies of laser triggered Z-pinch discharges

    OpenAIRE

    Tobin, Isaac

    2014-01-01

    This thesis describes the results of experiments with two geometries of laser assisted discharge plasma. Both devices are designed for fast Z-pinch discharge, triggered by laser produced plasma generated by ablation of one or both electrodes. The laser plasma parameters are adjusted to control the plasma load while the discharge parameters are adjusted to yield a rate of rise of current greater than 1010 A/s. The expansion dynamics and emission characteristics of the plasma were analysed, wit...

  15. Diagnostic of capacitively coupled radio frequency plasma from electrical discharge characteristics: comparison with optical emission spectroscopy and fluid model simulation

    Science.gov (United States)

    Xiang, HE; Chong, LIU; Yachun, ZHANG; Jianping, CHEN; Yudong, CHEN; Xiaojun, ZENG; Bingyan, CHEN; Jiaxin, PANG; Yibing, WANG

    2018-02-01

    The capacitively coupled radio frequency (CCRF) plasma has been widely used in various fields. In some cases, it requires us to estimate the range of key plasma parameters simpler and quicker in order to understand the behavior in plasma. In this paper, a glass vacuum chamber and a pair of plate electrodes were designed and fabricated, using 13.56 MHz radio frequency (RF) discharge technology to ionize the working gas of Ar. This discharge was mathematically described with equivalent circuit model. The discharge voltage and current of the plasma were measured at different pressures and different powers. Based on the capacitively coupled homogeneous discharge model, the equivalent circuit and the analytical formula were established. The plasma density and temperature were calculated by using the equivalent impedance principle and energy balance equation. The experimental results show that when RF discharge power is 50-300 W and pressure is 25-250 Pa, the average electron temperature is about 1.7-2.1 eV and the average electron density is about 0.5 × 1017-3.6 × 1017 m-3. Agreement was found when the results were compared to those given by optical emission spectroscopy and COMSOL simulation.

  16. Positional glow curve simulation for thermoluminescent detector (TLD) system design

    International Nuclear Information System (INIS)

    Branch, C.J.; Kearfott, K.J.

    1999-01-01

    Multi- and thin element dosimeters, variable heating rate schemes, and glow-curve analysis have been employed to improve environmental and personnel dosimetry using thermoluminescent detectors (TLDs). Detailed analysis of the effects of errors and optimization of techniques would be highly desirable. However, an understanding of the relationship between TL light production, light attenuation, and precise heating schemes is made difficult because of experimental challenges involved in measuring positional TL light production and temperature variations as a function of time. This work reports the development of a general-purpose computer code, thermoluminescent detector simulator, TLD-SIM, to simulate the heating of any TLD type using a variety of conventional and experimental heating methods including pulsed focused or unfocused lasers with Gaussian or uniform cross sections, planchet, hot gas, hot finger, optical, infrared, or electrical heating. TLD-SIM has been used to study the impact on the TL light production of varying the input parameters which include: detector composition, heat capacity, heat conductivity, physical size, and density; trapped electron density, the frequency factor of oscillation of electrons in the traps, and trap-conduction band potential energy difference; heating scheme source terms and heat transfer boundary conditions; and TL light scatter and attenuation coefficients. Temperature profiles and glow curves as a function of position time, as well as the corresponding temporally and/or spatially integrated glow values, may be plotted while varying any of the input parameters. Examples illustrating TLD system functions, including glow curve variability, will be presented. The flexible capabilities of TLD-SIM promises to enable improved TLD system design

  17. Electrical Versus Optical: Comparing Methods for Detecting Terahertz Radiation Using Neon Lamps

    Science.gov (United States)

    Slocombe, L. L.; Lewis, R. A.

    2018-05-01

    Terahertz radiation impinging on a lit neon tube causes additional ionization of the encapsulated gas. As a result, the electrical current flowing between the electrodes increases and the glow discharge in the tube brightens. These dual phenomena suggest two distinct modes of terahertz sensing. The electrical mode simply involves measuring the electrical current. The optical mode involves monitoring the brightness of the weakly ionized plasma glow discharge. Here, we directly compare the two detection modes under identical experimental conditions. We measure 0.1-THz radiation modulated at frequencies in the range 0.1-10 kHz, for lamp currents in the range 1-10 mA. We find that electrical detection provides a superior signal-to-noise ratio while optical detection has a faster response. Either method serves as the basis of a compact, robust, and inexpensive room-temperature detector of terahertz radiation.

  18. Electrical and optical analysis of fast transient discharges in a pulsed corona pilot unit

    NARCIS (Netherlands)

    Blom, P.P.M.; Smulders, H.W.M.; Heesch, van E.J.M.; Laan, van der P.C.T.

    1997-01-01

    We give a detailed analysis of intense pulsed corona dis charges. CCD movies and current, voltage and energy in put measurements are the basis of the description. The discharges are generated in a 1.5 kW pilot unit, which cre ates pulsed corona discharges energized by 100 kV pulses of 200 us width,

  19. Featured Image: Identifying a Glowing Shell

    Science.gov (United States)

    Kohler, Susanna

    2018-05-01

    New nebulae are being discovered and classified every day and this false-color image reveals one of the more recent objects of interest. This nebula, IPHASX J210204.7+471015, was recently imaged by the Andalucia Faint Object Spectrograph and Camera mounted on the 2.5-m Nordic Optical Telescope in La Palma, Spain. J210204 was initially identified as a possible planetary nebula a remnant left behind at the end of a red giants lifetime. Based on the above imaging, however, a team of authors led by Martn Guerrero (Institute of Astrophysics of Andalusia, Spain) is arguing that this shell of glowing gas was instead expelled around a classical nova. In a classical nova eruption, a white dwarf and its binary companion come very close together, and mass transfers to form a thin atmosphere of hydrogen around the white dwarf. When this hydrogen suddenly ignites in runaway fusion, this outer atmosphere can be expelled, forming a short-lived nova remnant which is what Guerrero and collaborators think were seeing with J210204. If so, this nebula can reveal information about the novathat caused it. To find out more about what the authors learned from this nebula, check out the paper below.CitationMartn A. Guerrero et al 2018 ApJ 857 80. doi:10.3847/1538-4357/aab669

  20. In-flight observation of long duration gamma-ray glows by aircraft

    Science.gov (United States)

    Kochkin, Pavlo; (Lex) van Deursen, A. P. J.; de Boer, Alte; Bardet, Michiel; Allasia, Cedric; Boissin, Jean Francois; Ostgaard, Nikolai

    2017-04-01

    The Gamma-Ray Glow is a long-lasting (several seconds to minutes) X- and gamma radiation presumably originated from high-electric field of thunderclouds. Such glows were previously observed by aircraft, balloons, and from the ground. When detected on ground with other particles, i.e. electrons and neutrons, they are usually called Thunderstorm Ground Enhancements (TGEs). Their measured spectra are often consistent with Relativistic Runaway Electron Avalanche (RREA) mechanism. That is why RREA is a commonly accepted explanation for their existence. The gamma-ray glows are observed to be interrupted by lightning discharge, which terminates the high-electric field region. In January 2016 an Airbus A340 factory test aircraft was performing intentional flights through thunderstorms over Northern Australia. The aircraft was equipped with a dedicated in-flight lightning detection system called ILDAS (http://ildas.nlr.nl). The system also contained two scintillation detectors each with 38x38 mm cylinder LaBr3 crystals. While being at 12 km altitude the system detected a gamma-ray flux enhancement 30 times the background counts. It lasted for 20 seconds and was abruptly terminated by a lightning flash. The flash hit the aircraft and its parameters were recorded with 10 ns sampling time including gamma radiation. Ground-based lightning detection network WWLLN detected 4 strikes in the nearby region, all in association with the same flash. The ILDAS system recorded the time-resolved spectrum of the glow. In 6 minutes, after making a U-turn, the aircraft passed the same glow region. Smaller gamma-ray enhancement was again detected. In this presentation we will show the mapped event timeline including airplane, gamma-ray glow, WWLLN, and cloud data. We will discuss the glow's properties, i.e. intensity and differential spectrum, and its possible origin. This result will also be compared to previously reported observations.

  1. Translational, rotational, vibrational and electron temperatures of a gliding arc discharge

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Ehn, Andreas; Gao, Jinlong

    2017-01-01

    , 0) band was used to simulate the rotational temperature (Tr) of the gliding arc discharge whereas the NO A–X (1, 0) and (0, 1) bands were used to determine its vibrational temperature (Tv). The instantaneous reduced electric field strength E/N was obtained by simultaneously measuring......Translational, rotational, vibrational and electron temperatures of a gliding arc discharge in atmospheric pressure air were experimentally investigated using in situ, non-intrusive optical diagnostic techniques. The gliding arc discharge was driven by a 35 kHz alternating current (AC) power source...... and operated in a glow-type regime. The two-dimensional distribution of the translational temperature (Tt) of the gliding arc discharge was determined using planar laser-induced Rayleigh scattering. The rotational and vibrational temperatures were obtained by simulating the experimental spectra. The OH A–X (0...

  2. Angina - discharge

    Science.gov (United States)

    Chest pain - discharge; Stable angina - discharge; Chronic angina - discharge; Variant angina - discharge; Angina pectoris - discharge; Accelerating angina - discharge; New-onset angina - discharge; Angina-unstable - discharge; ...

  3. Optical and electrical characteristics of hollow needle to plate atmospheric pressure discharge in nitrogen

    Czech Academy of Sciences Publication Activity Database

    Šimek, Milan; Schmidt, Jiří; Pekárek, S.; Khun, J.

    2006-01-01

    Roč. 51, č. 5 (2006), s. 27 ISSN 0003-0503. [Annual Gaseous Electronic Conference/59nd./. Columbus,Ohio, USA, 10.10.2006-13.10.2006] R&D Projects: GA AV ČR(CZ) IAA1043403 Institutional research plan: CEZ:AV0Z20430508 Keywords : positive corona discharge * streamer * mean repetition frequency * mean propagation velocity Subject RIV: BL - Plasma and Gas Discharge Physics

  4. Luminous phase of nanosecond discharge in deionized water: morphology, propagation velocity and optical emission.

    Czech Academy of Sciences Publication Activity Database

    Šimek, Milan; Pongrác, Branislav; Babický, Václav; Člupek, Martin; Lukeš, Petr

    2017-01-01

    Roč. 26, č. 7 (2017), č. článku 07LT01. ISSN 0963-0252 R&D Projects: GA ČR(CZ) GA15-12987S Institutional support: RVO:61389021 Keywords : water * nanosecond discharge * emission spectra * breakdown Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 3.302, year: 2016 http://iopscience.iop.org/article/10.1088/1361-6595/aa758d

  5. Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with neon

    International Nuclear Information System (INIS)

    Malinina, A. A.; Malinin, A. N.

    2013-01-01

    Results are presented from studies of the optical characteristics and parameters of plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with neon—the working medium of a non-coaxial exciplex gas-discharge emitter. The electron energy distribution function, the transport characteristics, the specific power losses for electron processes, the electron density and temperature, and the rate constants for the processes of elastic and inelastic electron scattering by the working mixture components are determined as functions of the reduced electric field. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules is found to be 1.6 × 10 −14 m 3 /s for a reduced electric field of E/N = 15 Td, at which the maximum emission intensity in the blue-green spectral region (λ max = 502 nm) was observed in this experiment

  6. Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with neon

    Science.gov (United States)

    Malinina, A. A.; Malinin, A. N.

    2013-12-01

    Results are presented from studies of the optical characteristics and parameters of plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with neon—the working medium of a non-coaxial exciplex gas-discharge emitter. The electron energy distribution function, the transport characteristics, the specific power losses for electron processes, the electron density and temperature, and the rate constants for the processes of elastic and inelastic electron scattering by the working mixture components are determined as functions of the reduced electric field. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules is found to be 1.6 × 10-14 m3/s for a reduced electric field of E/ N = 15 Td, at which the maximum emission intensity in the blue-green spectral region (λmax = 502 nm) was observed in this experiment.

  7. Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with neon

    Energy Technology Data Exchange (ETDEWEB)

    Malinina, A. A., E-mail: alexandr_malinin@rambler.ru; Malinin, A. N. [Uzhhorod National University (Ukraine)

    2013-12-15

    Results are presented from studies of the optical characteristics and parameters of plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with neon—the working medium of a non-coaxial exciplex gas-discharge emitter. The electron energy distribution function, the transport characteristics, the specific power losses for electron processes, the electron density and temperature, and the rate constants for the processes of elastic and inelastic electron scattering by the working mixture components are determined as functions of the reduced electric field. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules is found to be 1.6 × 10{sup −14} m{sup 3}/s for a reduced electric field of E/N = 15 Td, at which the maximum emission intensity in the blue-green spectral region (λ{sub max} = 502 nm) was observed in this experiment.

  8. Optical and structural properties of carbon dots/TiO2 nanostructures prepared via DC arc discharge in liquid

    Science.gov (United States)

    Biazar, Nooshin; Poursalehi, Reza; Delavari, Hamid

    2018-01-01

    Synthesis and development of visible active catalysts is an important issue in photocatalytic applications of nanomaterials. TiO2 nanostructures coupled with carbon dots demonstrate a considerable photocatalytic activity in visible wavelengths. Extending optical absorption of a wide band gap semiconductor such as TiO2 with carbon dots is the origin of the visible activity of carbon dots modified semiconductor nanostructures. In addition, carbon dots exhibit high photostability, appropriate electron transport and chemical stability without considerable toxicity or environmental footprints. In this study, optical and structural properties of carbon dots/TiO2 nanostructures prepared via (direct current) DC arc discharge in liquid were investigated. Crystal structure, morphology and optical properties of the samples were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-visible spectroscopy respectively. SEM images show formation of spherical nanoparticles with an average size of 27 nm. In comparison with pristine TiO2, optical transmission spectrum of carbon dots/TiO2 nanostructures demonstrates an absorption edge at longer wavelengths as well a high optical absorption in visible wavelengths which is significant for visible activity of nanostructures as a photocatalyst. Finally, these results can provide a flexible and versatile pathway for synthesis of carbon dots/oxide semiconductor nanostructures with an appropriate activity under visible light.

  9. The thermoluminescence glow-curve analysis using GlowFit - the new powerful tool for deconvolution

    International Nuclear Information System (INIS)

    Puchalska, M.; Bilski, P.

    2005-10-01

    A new computer program, GlowFit, for deconvoluting first-order kinetics thermoluminescence (TL) glow-curves has been developed. A non-linear function describing a single glow-peak is fitted to experimental points using the least squares Levenberg-Marquardt method. The main advantage of GlowFit is in its ability to resolve complex TL glow-curves consisting of strongly overlapping peaks, such as those observed in heavily doped LiF:Mg,Ti (MTT) detectors. This resolution is achieved mainly by setting constraints or by fixing selected parameters. The initial values of the fitted parameters are placed in the so-called pattern files. GlowFit is a Microsoft Windows-operated user-friendly program. Its graphic interface enables easy intuitive manipulation of glow-peaks, at the initial stage (parameter initialization) and at the final stage (manual adjustment) of fitting peak parameters to the glow-curves. The program is freely downloadable from the web site www.ifj.edu.pl/NPP/deconvolution.htm (author)

  10. Sintering unalloyed titanium in DC electrical abnormal glow discharge

    Directory of Open Access Journals (Sweden)

    Allan Seeber

    2010-03-01

    Full Text Available Powder metallurgy is widely used in the manufacture of components that have complex geometry. The good dimensional control, reduction in manufacturing steps and operating costs which has favored the use of this technique for manufacturing of titanium alloys components. However, the high affinity of this material with oxygen hinders strongly the sintering process. For this, the sintering associated with plasma technology can be considered an alternative technique for the processing of this material. The strict control of sintering atmosphere performed at low pressures and the reactive species present in the plasma environment can help to improve the sintering of this material. The results presented in this paper show a good correlation between the parameters used for the compaction of the samples and the microstructure develop during the plasma sintering of samples. The microstructure of the plasma assisted samples is also affected by the particular configuration used in the plasma reactor.

  11. Glow discharge processing in the liquid crystal display industry

    International Nuclear Information System (INIS)

    Schmitt, Jacques; Elyaakoubi, Mustapha; Sansonnens, Laurent

    2002-01-01

    The active matrix display industry is rapidly presented. The most challenging aspect for plasma source design lies in the substrate size which is now entering the 1-2 m range. This paper focuses on the conventional planar RF capacitor at 13.56 MHz. A detailed analysis of the local perturbation due to a hole in the metal susceptor illustrates the process effects of various plasma microscopic parameters. It appears that not only the process rate must be kept uniform, but also the ion bombardment. It is also shown that very wide capacitive reactors no longer follow some classical rules: (1) plasma RF conductivity is limited, its propagation is shown to be described by a telegraph equation, in agreement with numerical modelling and electrostatic measurements, (2) the RF wavelength is no longer infinite compared to the dimensions, this leads to standing waves. The presence of the plasma is shown to worsen the effect by shortening the RF propagation wavelength

  12. Spectroscopic Investigation of the Argon Metastable State Through Optical Emission From Pulsed Argon Discharge

    Science.gov (United States)

    2010-07-01

    supply to energize the discharge was connected in series with an ohmite L225J high power 150 Ω resistor and the hollow electrode anode. A stainless...input analog voltage signal to control a piezo -electric actuator within the diode laser head. The general beam path of the diode laser involved an initial

  13. Plasma flow discharge researches at the PIRIT-2000 facility

    International Nuclear Information System (INIS)

    Popkov, N.F.; Ryaslov, E.A.; Kargin, V.I.; Pikar', A.S.; Vorontsov, V.I.; Kotel'nikov, D.V.; Melkozerov, A.V.

    1996-01-01

    Investigation of a plasma flow switch at the PIRIT-2000 fast operating capacitor bank is reported. The maximum current of the plasma flow discharge (PFD) reaches 5 MA, the current rise time being as low as 100 ns. The magnetic field strength of the plasma flow switch (0.15 T) is about 15 times higher than that of the plasma erosion switch used earlier. Both magnetic probe and optical methods were used in the experiments. From the magnetic probes data the propagating velocity of a current carrying shell (205 cm/s) has been derived, while the optical method is used for determining the velocity of a glowing plasma layer. At varying the operation delay in the range 2-10 s the PFD load current rise time increases up to 150-200 ns, the prepulse increment reaching its maximum at the delays higher than 6 s. (J.U.). 5 figs., 5 refs

  14. Plasma flow discharge researches at the PIRIT-2000 facility

    Energy Technology Data Exchange (ETDEWEB)

    Popkov, N F; Ryaslov, E A; Kargin, V I; Pikar` , A S; Vorontsov, V I; Kotel` nikov, D V; Melkozerov, A V [All-Russian Scientific Research Inst. of Experimental Physics, Sarov (Russian Federation)

    1997-12-31

    Investigation of a plasma flow switch at the PIRIT-2000 fast operating capacitor bank is reported. The maximum current of the plasma flow discharge (PFD) reaches 5 MA, the current rise time being as low as 100 ns. The magnetic field strength of the plasma flow switch (0.15 T) is about 15 times higher than that of the plasma erosion switch used earlier. Both magnetic probe and optical methods were used in the experiments. From the magnetic probes data the propagating velocity of a current carrying shell (205 cm/s) has been derived, while the optical method is used for determining the velocity of a glowing plasma layer. At varying the operation delay in the range 2-10 s the PFD load current rise time increases up to 150-200 ns, the prepulse increment reaching its maximum at the delays higher than 6 s. (J.U.). 5 figs., 5 refs.

  15. Anodisation of sputter deposited aluminium–titanium coatings: Effect of microstructure on optical characteristics

    DEFF Research Database (Denmark)

    Aggerbeck, Martin; Junker-Holst, Andreas; Vestergaard Nielsen, Daniel

    2014-01-01

    Magnetron sputtered coatings of aluminium containing up to 18 wt.% titanium were deposited on aluminium substrates to study the effect of microstructure on the optical appearance of the anodised layer. The microstructure and morphology were studied using transmission electron microscopy (TEM), X......-ray diffraction (XRD), and glow discharge optical emission spectroscopy (GDOES), while the optical appearance was investigated using photospectrometry. The microstructure of the coatings was varied by heat treatment, resulting in the precipitation of Al3Ti phases. The reflectance of the anodised surfaces...

  16. Photo-triggering and secondary electron produced ionization in electric discharge ArF* excimer lasers

    Science.gov (United States)

    Xiong, Zhongmin; Kushner, Mark J.

    2011-10-01

    Electric discharge excimer lasers are sustained in multi-atmosphere attaching gas mixtures that are typically preionized to enable a reproducible, uniform glow, which maximizes optical quality and gain. This preionization is often accomplished using UV light produced by a corona discharge within the plasma cavity. To quantify the relationship between corona discharge properties and those of the laser discharge, the triggering of electron avalanche by preionizing UV light in an electric discharge-pumped ArF* excimer laser was numerically investigated using a two-dimensional model. The preionizing UV fluxes were generated by a corona-bar discharge driven by the same voltage pulse as the main discharge sustained in a multi-atmospheric Ne/Ar/Xe/F2 gas mixture. The resulting peak photo-electron density in the inter-electrode spacing is around 108 cm-3, and its distribution is biased toward the UV source. The preionization density increases with increasing dielectric constant and capacitance of the corona bar. The symmetry and uniformity of the discharge are, however, improved significantly once the main avalanche develops. In addition to bulk electron impact ionization, the ionization generated by sheath accelerated secondary electrons was found to be important in sustaining the discharge current at experimentally observed values. At peak current, the magnitude of the ionization by sheath accelerated electrons is comparable to that from bulk electron impact in the vicinity of the cathode.

  17. [Measurement of plasma parameters in cluster hexagon pattern discharge by optical emission spectrum].

    Science.gov (United States)

    Dong, Li-Fang; Shen, Zhong-Kai; Li, Xin-Chun; Liu, Liang; Lu, Ning; Shang, Jie

    2012-09-01

    The cluster hexagon pattern was obtained in a dielectric barrier discharge in air/argon for the first time. Three plasma parameters, i. e. the molecular vibrational temperature, the molecular rotational temperature and the average electron energy of individual cluster in cluster hexagon pattern discharge, were studied by changing the air content. The molecular vibrational temperature and the molecular rotational temperature were calculated using the second positive band system of nitrogen molecules (C 3IIu --> B 3IIg) and the first negative band system of nitrogen molecular ions (B 2Sigma(u)+ --> Chi2 Sigma(g)+). The relative intensities of the first negative system of nitrogen molecular ions (391. 4 nm) and nitrogen molecules emission spectrum line (337.1 nm) were analyzed for studying the variations of the electron energy. It was found that the three plasma parameters of individual cluster in cluster hexagon pattern increase with air content increasing from 16% to 24%.

  18. [Study on plasma parameters in diffuse discharge with semispherical electrod by optical emission spectrum].

    Science.gov (United States)

    Dong, Li-Fang; Tong, Guo-Liang; Shen, Zhong-Kai; Liu, Liang; Ji, Ya-Fei; Zhao, Huan-Huan

    2012-06-01

    The diffuse discharge plasma in air was observed in a dielectric barrier discharge with two semispherical water electrodes. The variations of vibration temperature, rotation temperature, and average electron energy as the function of the applied voltage were studied by emission spectroscopy. The vibration temperature and the rotation temperature were calculated through the second positive band system (C3Pi(u)-->B3Pi(g)) of N2+ and the first negative band system (B2 Sigma(u+)-->Chi2Sigma(g+)) of N(2+) respectively. The average electron energy was studied by intensity ratio of 391.4 and 337.1 nm. It was found that the rotation temperature increases with the applied voltage increasing, while the vibration temperature and the electron energy decrease.

  19. Electric discharge during electrosurgery.

    Science.gov (United States)

    Shashurin, Alexey; Scott, David; Zhuang, Taisen; Canady, Jerome; Beilis, Isak I; Keidar, Michael

    2015-04-16

    Electric discharge utilized for electrosurgery is studied by means of a recently developed method for the diagnostics of small-size atmospheric plasma objects based on Rayleigh scattering of microwaves on the plasma volume. Evolution of the plasma parameters in the near-electrode sheaths and in the positive column is measured and analyzed. It is found that the electrosurgical system produces a glow discharge of alternating current with strongly contracted positive column with current densities reaching 10(3) A/cm(2). The plasma electron density and electrical conductivities in the channel were found be 10(16) cm(-3) and (1-2) Ohm(-1) cm(-1), respectively. The discharge interrupts every instance when the discharge-driving AC voltage crosses zero and re-ignites again every next half-wave at the moment when the instant voltage exceeds the breakdown threshold.

  20. Combined optical emission and resonant absorption diagnostics of an Ar-O{sub 2}-Ce-reactive magnetron sputtering discharge

    Energy Technology Data Exchange (ETDEWEB)

    El Mel, A.A. [Chimie des Interactions Plasma-Surface (ChIPS), Research Institute for Materials Science and Engineering, Université de Mons, Place du Parc 23, Mons B-7000 (Belgium); Institut des Matériaux Jean Rouxel, Université de Nantes, CNRS, 2 rue de la Houssinière B.P. 32229, Nantes Cedex 3 44322 (France); Ershov, S. [Chimie des Interactions Plasma-Surface (ChIPS), Research Institute for Materials Science and Engineering, Université de Mons, Place du Parc 23, Mons B-7000 (Belgium); Britun, N., E-mail: nikolay.britun@umons.ac.be [Chimie des Interactions Plasma-Surface (ChIPS), Research Institute for Materials Science and Engineering, Université de Mons, Place du Parc 23, Mons B-7000 (Belgium); Ricard, A. [Université de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d' Energie), 118 route de Narbonne, Toulouse Cedex 9 F-31062 (France); Konstantinidis, S. [Chimie des Interactions Plasma-Surface (ChIPS), Research Institute for Materials Science and Engineering, Université de Mons, Place du Parc 23, Mons B-7000 (Belgium); Snyders, R. [Chimie des Interactions Plasma-Surface (ChIPS), Research Institute for Materials Science and Engineering, Université de Mons, Place du Parc 23, Mons B-7000 (Belgium); Materia Nova Research Center, Parc Initialis, Avenue Copernic 1, Mons B-7000 (Belgium)

    2015-01-01

    We report the results on combined optical characterization of Ar-O{sub 2}-Ce magnetron sputtering discharges by optical emission and resonant absorption spectroscopy. In this study, a DC magnetron sputtering system equipped with a movable planar magnetron source with a Ce target is used. The intensities of Ar, O, and Ce emission lines, as well as the absolute densities of Ar metastable and Ce ground state atoms are analyzed as a function of the distance from the magnetron target, applied DC power, O{sub 2} content, etc. The absolute number density of the Ar{sup m} is found to decrease exponentially as a function of the target-to-substrate distance. The rate of this decrease is dependent on the sputtering regime, which should be due to the different collisional quenching rates of Ar{sup m} by O{sub 2} molecules at different oxygen contents. Quantitatively, the absolute number density of Ar{sup m} is found to be equal to ≈ 3 × 10{sup 8} cm{sup −3} in the metallic, and ≈ 5 × 10{sup 7} cm{sup −3} in the oxidized regime of sputtering, whereas Ce ground state densities at the similar conditions are found to be few times lower. The absolute densities of species are consistent with the corresponding deposition rates, which decrease sharply during the transition from metallic to poisoned sputtering regime. - Highlights: • Optical emission and resonant absorption spectroscopy are employed to study Ar-O{sub 2}-Ce magnetron sputtering discharges. • The density of argon metastables is found to decrease exponentially when increasing the target-to-substrate distance. • The collision-quenching rates of Ar{sup m} by O{sub 2} molecules at different oxygen contents is demonstrated. • The deposition rates of cerium and cerium oxide thin films decrease sharply during the transition from the metallic to the poisoned sputtering regime.

  1. Interaction of current filaments in dielectric barrier discharges with relation to surface charge distributions

    International Nuclear Information System (INIS)

    Stollenwerk, L

    2009-01-01

    In a planar, laterally extended dielectric barrier discharge (DBD) system operated in glow mode, a filamentary discharge is observed. The filaments tend to move laterally and hence tend to cause collisions. Thereby, usually one collision partner becomes destroyed. In this paper, the collision process and especially the preceding time period is investigated. Beside the luminescence density of the filaments, the surface charge density accumulated between the single breakdowns of the DBD is observed via an optical measurement technique based on the linear electro-optical effect (pockels effect). A ring-like substructure of the surface charge distribution of a single filament is found, which correlates to the filament interaction behaviour. Furthermore, a preferred filament distance is found, suggesting the formation of a filamentary quasi-molecule.

  2. In-Flight Observation of Gamma Ray Glows by ILDAS

    Science.gov (United States)

    Kochkin, Pavlo; van Deursen, A. P. J.; Marisaldi, M.; Ursi, A.; de Boer, A. I.; Bardet, M.; Allasia, C.; Boissin, J.-F.; Flourens, F.; Østgaard, N.

    2017-12-01

    An Airbus A340 aircraft flew over Northern Australia with the In-Flight Lightning Damage Assessment System (ILDAS) installed onboard. A long-duration gamma ray emission was detected. The most intense emission was observed at 12 km altitude and lasted for 20 s. Its intensity was 20 times the background counts, and it was abruptly terminated by a distant lightning flash. In this work we reconstruct the aircraft path and event timeline. The glow-terminating flash triggered a discharge from the aircraft wing that was recorded by a video camera operating onboard. Another count rate increase was observed 6 min later and lasted for 30 s. The lightning activity as reported by ground networks in this region was analyzed. The measured spectra characteristics of the emission were estimated.

  3. On the formation mechanisms of the diffuse atmospheric pressure dielectric barrier discharge in CVD processes of thin silica-like films

    Energy Technology Data Exchange (ETDEWEB)

    Starostin, S A; Premkumar, P Antony [Materials Innovation Institute (M2i), Mekelweg 2, 2600 GA Delft, The Netherland (Netherlands); Creatore, M; Van Veldhuizen, E M; Van de Sanden, M C M [Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); De Vries, H; Paffen, R M J [FUJIFILM Manufacturing Europe B.V, PO Box 90156, Tilburg (Netherlands)

    2009-11-15

    Pathways of formation and temporal evolution of the diffuse dielectric barrier discharge at atmospheric pressure were experimentally studied in this work by means of optical (fast imaging camera) and electrical diagnostics. The chosen model system is relevant for applications of plasma-enhanced chemical vapor deposition of thin silica-like film on the polymeric substrate, from cost-efficient gas mixtures of Ar/N{sub 2}/O{sub 2}/hexamethyldisiloxane. It was found that the discharge can gradually experience the phases of homogeneous low current Townsend-like mode, local Townsend to glow transition and expanding high current density ({approx}0.7 A cm{sup -2}) glow-like mode. While the glow-like current spot occupies momentarily only a small part of the electrode area, its expanding behavior provides uniform treatment of the whole substrate surface. Alternatively, it was observed that a visually uniform discharge can be formed by the numerous microdischarges overlapping over the large electrode area.

  4. Using limnological and optical knowledge to detect discharges from nuclear facilities - Potential application of satellite imagery for international safeguards

    International Nuclear Information System (INIS)

    Borstad, G.; Truong, Q.S. Bob; Keeffe, R.; Baines, P.; Staenz, K.; Neville, R.

    2001-01-01

    Previous work carried out under the Canadian Safeguards Support Program, has shown that thermal imagery from the American Landsat satellites could be used to detect the cooling water discharges, and could therefore be used to verify the operational status of nuclear facilities. In some images, thermal plumes could be easily detected in single band imagery with no mathematical manipulation and little image enhancement because there was a very strong thermal contrast between the effluent and the receiving water. However, for certain situations such as discharges into well mixed conditions (cold water and violent tides) the thermal plume may be more subtle. We show here that the visible bands of Landsat and IKONOS images often contain additional information, and that the thermal signature of a discharge from a nuclear facility is not the only signal available to describe its operation. This paper introduces some important hydrological phenomena that govern the biological and physical organization of water bodies, and discusses some basic concepts of marine and aquatic optics that are relevant to the safeguards problem. Using image analysis techniques that have been used widely in ocean optics work and in applications in the mapping and monitoring of water quality, we have re-analyzed data that were obtained under a joint project between various Canadian government departments. We present a preliminary examination of imagery from both satellite multispectral and aircraft hyperspectral sensors, and discuss methods to extract information that could be useful in the detection and verification of declared or undeclared nuclear activities. In one example of an IKONOS image of the Canadian Bruce Nuclear Generating Facility, simple enhancement techniques failed to find any plume other than a small jet visible in the surface wave field. With knowledge of limnology, oceanography and aquatic optics, we have been able to separate and remove the surface reflection, and detect a

  5. Discharge cleaning for a tokamak

    International Nuclear Information System (INIS)

    Ishii, Shigeyuki

    1983-01-01

    Various methods of discharge cleaning for tokamaks are described. The material of the first walls of tokamaks is usually stainless steel, inconel, titanium and so on. Hydrogen is exclusively used as the discharge gas. Glow discharge cleaning (GDC), Taylor discharge cleaning (TDC), and electron cyclotron resonance discharge cleaning (ECR-DC) are discussed in this paper. The cleaning by GDC is made by moving a movable anode to the center of a tokamak vassel. Taylor found the good cleaning effect of induced discharge by high pressure and low power discharge. This is called TDC. When the frequency of high frequency discharge in a magnetic field is equal to that of the electron cyclotron resonance, the break down potential is lowered if the pressure is sufficiently low. The ECR-CD is made by using this effect. In TDC and ECR-DC, the electron temperature, which has a close relation to the production rate of H 0 , can be controlled by the pressure. In GDC, the operating pressure was improved by the radio frequency glow (RG) method. However, there is still the danger of arcing. In case of GDC and ECR-DC, the position of plasma can be controlled, but not in case of TDC. The TDC is accepted by most of takamak devices in the world. (Kato, T.)

  6. Dynamic study of dual high-power impulse magnetron sputtering discharge by optical emission imaging

    Czech Academy of Sciences Publication Activity Database

    Straňák, V.; Bogdanowicz, R.; Drache, S.; Čada, Martin; Hubička, Zdeněk; Hippler, R.

    2011-01-01

    Roč. 39, č. 11 (2011), 2454-2455 ISSN 0093-3813 R&D Projects: GA AV ČR KAN301370701; GA ČR GP202/09/P159; GA ČR GA202/09/0800 Grant - others:AVČR(CZ) M100100915 Institutional research plan: CEZ:AV0Z10100522 Keywords : magnetic confinement * plasma properties * plasma sources Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.174, year: 2011

  7. Optical spectroscopy versus mass spectrometry: The race for fieldable isotopic analysis

    International Nuclear Information System (INIS)

    Barshick, C.M.; Young, J.P.; Shaw, R.W.

    1995-01-01

    Several techniques have been developed to provide on-site isotopic analyses, including decay-counting and mass spectrometry, as well as methods that rely on the accessibility of optical transitions for isotopic selectivity (e.g., laser-induced fluorescence and optogalvanic spectroscopy). The authors have been investigating both mass spectrometry and optogalvanic spectroscopy for several years. Although others have considered these techniques for isotopic analysis, the authors have focussed on the use of a dc glow discharge for atomization and ionization, and a demountable discharge cell for rapid sample exchange. The authors' goal is a fieldable instrument that provides useful uranium isotope ratio information

  8. Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with argon

    Science.gov (United States)

    Malinina, A. A.; Malinin, A. N.

    2015-03-01

    Results are presented from studies of the optical characteristics and parameters of the plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with argon—the working medium of an exciplex gas-discharge emitter. It is established that the partial pressures of mercury dibromide vapor and argon at which the average and pulsed emission intensities in the blue—green spectral region (λmax = 502 nm) reach their maximum values are 0.6 and 114.4 kPa, respectively. The electron energy distribution function, the transport characteristics, the specific power spent on the processes involving electrons, the electron density and temperature, and the rate constants for the processes of elastic and inelastic electron scattering from the molecules and atoms of the working mixture are determined by numerical simulation, and their dependences on the reduced electric field strength are analyzed. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules for a reduced electric field of E/ N = 20 Td, at which the maximum emission intensity in the blue—green spectral region was observed in this experiment, is found to be 8.1 × 10-15 m3/s.

  9. Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with argon

    Energy Technology Data Exchange (ETDEWEB)

    Malinina, A. A., E-mail: alexandr-malinin@rambler.ru; Malinin, A. N. [Uzhhorod National University (Ukraine)

    2015-03-15

    Results are presented from studies of the optical characteristics and parameters of the plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with argon—the working medium of an exciplex gas-discharge emitter. It is established that the partial pressures of mercury dibromide vapor and argon at which the average and pulsed emission intensities in the blue—green spectral region (λ{sub max} = 502 nm) reach their maximum values are 0.6 and 114.4 kPa, respectively. The electron energy distribution function, the transport characteristics, the specific power spent on the processes involving electrons, the electron density and temperature, and the rate constants for the processes of elastic and inelastic electron scattering from the molecules and atoms of the working mixture are determined by numerical simulation, and their dependences on the reduced electric field strength are analyzed. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules for a reduced electric field of E/N = 20 Td, at which the maximum emission intensity in the blue—green spectral region was observed in this experiment, is found to be 8.1 × 10{sup −15} m{sup 3}/s.

  10. Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with argon

    International Nuclear Information System (INIS)

    Malinina, A. A.; Malinin, A. N.

    2015-01-01

    Results are presented from studies of the optical characteristics and parameters of the plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with argon—the working medium of an exciplex gas-discharge emitter. It is established that the partial pressures of mercury dibromide vapor and argon at which the average and pulsed emission intensities in the blue—green spectral region (λ max = 502 nm) reach their maximum values are 0.6 and 114.4 kPa, respectively. The electron energy distribution function, the transport characteristics, the specific power spent on the processes involving electrons, the electron density and temperature, and the rate constants for the processes of elastic and inelastic electron scattering from the molecules and atoms of the working mixture are determined by numerical simulation, and their dependences on the reduced electric field strength are analyzed. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules for a reduced electric field of E/N = 20 Td, at which the maximum emission intensity in the blue—green spectral region was observed in this experiment, is found to be 8.1 × 10 −15 m 3 /s

  11. Land-ocean contrast on electrical characteristics of lightning discharge derived from satellite optical measurements

    Science.gov (United States)

    Adachi, T.; Said, R.; Cummer, S. A.; Li, J.; Takahashi, Y.; Hsu, R.; Su, H.; Chen, A. B.; Mende, S. B.; Frey, H. U.

    2010-12-01

    Comparative studies on the electrical properties of oceanic and continental lightning are crucial to elucidate air discharge processes occurring under different conditions. Past studies however have primarily focused on continental lightning because of the limited coverage of ground-based instruments. Recent satellite measurements by FORMOSAT-2/ISUAL provided a new way to survey the global characteristics of lightning and transient luminous events regardless of land and ocean. In this study, we analyze ISUAL/spectrophotometer data to clarify the electrical properties of lightning on a global level. Based on the results obtained by Cummer et al. [2006] and Adachi et al. [2009], the OI-777.4nm emission intensity is used to infer lightning electrical parameters. Results show a clear land-ocean contrast on the parameters of lightning discharge: in oceanic lightning, peak luminosity is 60 % higher and the time scale of return stroke is 30 % shorter. These results suggest higher peak current in oceanic lightning, which is consistent with the fact that elves, EMP-driven phenomena, also tend to occur over the ocean [Chen et al., 2008]. Further analysis of lightning events occurring around the Caribbean Sea shows that the transition-line of lightning electrical properties is precisely located along the coastline. We suggest that the differences in these electrical properties may be due to the boundary conditions (conductivity, surface terrain, etc). In this talk, based on the calibration with NLDN and Duke magnetometer data, current moment change and charge moment change will be globally evaluated using a complete set of the ISUAL-observed lightning events.

  12. Measurement of the current in water discharge using magneto-optical Faraday effect

    International Nuclear Information System (INIS)

    Sarkisov, G.S.; Woodworth, J.R.

    2006-01-01

    The observation of magnetooptical Faraday effects in water in experiments with electrical breakdown is presented. After high-voltage breakdown, the ionized channel with ∼4 kA current was generated. The magnetic field from the current channel induces a circular birefringence which results in rotation of the polarization plane of a probing laser (200 ps, 532 nm). In spite of fast opposite radius drop of the magnetic field in radial direction, the Faraday rotation effect drops very slowly. The rotation of the polarization plane was ∼0.65 deg. ±5%. The optical measurements are in good agreement within ∼7% with the electrical measurements of the current

  13. Columnar discharge mode between parallel dielectric barrier electrodes in atmospheric pressure helium

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Yanpeng; Zheng, Bin; Liu, Yaoge [School of Electric Power, South China University of Technology, Guangzhou 510640 (China)

    2014-01-15

    Using a fast-gated intensified charge-coupled device, end- and side-view photographs were taken of columnar discharge between parallel dielectric barrier electrodes in atmospheric pressure helium. Based on three-dimensional images generated from end-view photographs, the number of discharge columns increased, whereas the diameter of each column decreased as the applied voltage was increased. Side-view photographs indicate that columnar discharges exhibited a mode transition ranging from Townsend to glow discharges generated by the same discharge physics as atmospheric pressure glow discharge.

  14. High powered pulsed plasma enhanced deposition of thin film semiconductor and optical materials

    International Nuclear Information System (INIS)

    Llewellyn, I.P.; Sheach, K.J.A.; Heinecke, R.A.

    1993-01-01

    A glow discharge deposition technique is described which allows the deposition of a large range of high quality materials without the requirement for substrate heating. The method is differentiated from conventional plasma deposition techniques in that a much higher degree of dissociation is achieved in the gases prior to deposition, such that thermally activated surface reactions are no longer required in order to produce a dense film. The necessary discharge intensity (>300Wcm -3 ) is achieved using a high power radio frequency generator which is pulsed at a low duty cycle (1%) to keep the average energy of the discharge low (100W), in order to avoid the discharge heating the substrate. In addition, by varying the gas composition between discharge pulses, layered structures of materials can be produced, with a disordered interface about 8 A thick. Various uses of the technique in semiconductor and optical filter production are described, and the properties of films deposited using these technique are presented. (orig.)

  15. Spatially and temporally resolved detection of arsenic in a capillary dielectric barrier discharge by hydride generation high-resolved optical emission spectrometry

    Czech Academy of Sciences Publication Activity Database

    Burhenn, S.; Kratzer, Jan; Svoboda, Milan; Klute, F. D.; Michels, A.; Veža, D.; Franzke, J.

    2018-01-01

    Roč. 90, MAR (2018), s. 3424-3429 ISSN 0003-2700 R&D Projects: GA ČR GA17-04329S Institutional support: RVO:68081715 Keywords : dielectric barrier discharge * optical emission spectroscopy * arsenic hydride Subject RIV: CB - Analytical Chemistry , Separation OBOR OECD: Analytical chemistry Impact factor: 6.320, year: 2016

  16. Spatially and temporally resolved detection of arsenic in a capillary dielectric barrier discharge by hydride generation high-resolved optical emission spectrometry

    Czech Academy of Sciences Publication Activity Database

    Burhenn, S.; Kratzer, Jan; Svoboda, Milan; Klute, F. D.; Michels, A.; Veža, D.; Franzke, J.

    2018-01-01

    Roč. 90, MAR (2018), s. 3424-3429 ISSN 0003-2700 R&D Projects: GA ČR GA17-04329S Institutional support: RVO:68081715 Keywords : dielectric barrier discharge * optical emission spectroscopy * arsenic hydride Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 6.320, year: 2016

  17. A dielectric barrier discharge in neon at atmospheric pressure

    International Nuclear Information System (INIS)

    Ran Junxia; Luo Haiyun; Wang Xinxin

    2011-01-01

    A dielectric barrier discharge in neon at atmospheric pressure is investigated with electrical measurement and fast photography. It is found that a stable diffuse discharge can be easily generated in a gap with a gap space of 0.5-6 mm and is identified with a glow discharge. The first breakdown voltage of the gap is considerably higher than that of the same gap working in a stable diffuse discharge mode, which indicates that Penning ionization of neon metastables from the previous discharge with inevitable gas impurities plays an important role in the decrease in the breakdown voltage. Discharge patterns are observed in a gap shorter than 1 mm. From the experiments with a wedge-like gap, it is found that the discharge patterns are formed in the area with a higher applied electric field, which suggests that a higher applied electric field may cause a transition from a diffuse glow to discharge patterns.

  18. The Electrostatic Environments of Mars: Atmospheric Discharges

    Science.gov (United States)

    Calle, Carlos I.; Mackey, Paul J.; Johansen, Michael R.; Hogue, Michael D.; Phillips, James, III; Cox, Rachel E.

    2016-01-01

    The electrostatic environment on Mars is controlled by its ever present atmospheric dust. Dust devils and dust storms tribocharge this dust. Theoretical studies predict that lightning and/or glow discharges should be present on Mars, but none have been directly observed. Experiments are planned to shed light on this issue.

  19. Temporal evolution of the after glow plasma conductivity

    International Nuclear Information System (INIS)

    Surmeian, A.; Diplasu, C.; Musa, G.; Popescu, I-Iovitz

    2001-01-01

    Due to their exhibited advantages over continuous and RF glows, the pulsed discharges gain more attention in a wide variety of application fields, like film deposition, plasma chemistry, semiconductor processing, etc. For this reason, fast time-resolved experimental methods need to be developed in order to control the main parameters of the high voltage pulsed plasmas. It is well known that electric probes present major advantages over many other diagnostic techniques for studying plasma parameters, but the use of these probes in the high voltage pulsed plasmas encounters enormous difficulties. One of them is the issue of galvanic insulation of the probe during the high voltage pulse. Also, the plasma potential may change rapidly, inducing spurious currents in the probe. Other problems could arise in the afterglow when the probe can exert great influence over the plasma potential by the current that it draws from the plasma. In this paper, we proposed a new method for the determination of the electrical conductivity of the afterglow of the high voltage pulsed discharges, using a low frequency RF plane probe. The application of a small low frequency signal to the plane probe could successfully eliminate all the disadvantages mentioned above. (authors)

  20. Technique of experimental measurements of the optical thickness of a pulse discharge plasma channel in water on a contour reabsorption lines of hydrogen Hα

    Directory of Open Access Journals (Sweden)

    O. A. Fedorovich

    2010-03-01

    Full Text Available In this work the results of development and application of the technique of experimental definition of optical thickness (τ of the pulse discharge plasma channel in water which are based on the distribution of radiation intensities on contour reabsorption lines of hydrogen Ha (656.3 nm are given. Optical thickness of continues spectrum was defined by extrapolation of intensities in far wing of contour reabsorption lines of hydrogen Ha, where t value did not vary any more, and the line smoothly transferred in continuous spectrum. The atomic concentration Na, received on a method of definition of t on a contour reabsorption lines of hydrogen Ha., agreed with calculation obtained from the equation of the plasma state. The recommendations on the correct definition of optical thickness of plasma of pulse discharge in liquids are given.