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Sample records for ar gas filled

  1. Effect of adding Ar gas on the pulse height distribution of BF3-filled neutron detectors

    Indian Academy of Sciences (India)

    M Padalakshmi; A M Shaikh

    2008-11-01

    Boron trifluoride (BF3) proportional counters are used as detectors for thermal neutrons. They are characterized by high neutron sensitivity and good gamma discriminating properties. Most practical BF3 counters are filled with pure boron trifluoride gas enriched up to 96% 10B. But BF3 is not an ideal proportional counter gas. Worsening of plateau characteristics is observed with increasing radius due to impurities in gas. To overcome this problem, counters are filled with BF3 with an admixture of a more suitable gas such as argon. The dilution of BF3 with argon causes a decrease in detection efficiency, but the pulse height spectrum shows sharper peaks and more stable plateau characteristics than counters filled with pure BF3. The present investigations are under-taken to study the pulse height distribution and other important factors in BF3+Ar filled signal counters for neutron beam applications. Tests are performed with detectors with cylindrical geometry filled with BF3 gas enriched in 10B to 90%, and high purity Ar in different proportions. By analysing pulse height spectra, a value of 6.1 ± 0.2 has been obtained for the branching ratio of the 10B(,) reaction.

  2. Simulation model for analyzing voltage-current characteristics of the barrier type lamp filled with Hg-Ar gas

    Science.gov (United States)

    Watanabe, Yoshio; Yamaguchi, Tomohiro; Imada, Ryosuke

    2013-09-01

    The simulation model for DBD lamp filled with Hg-Ar gas is studied. The straight tube filled with Hg and Ar gases is employed as a lamp. Three kinds of applied voltage waveforms at high frequency are applied between the pair of stripe electrodes attached on the outside of the tube. One dimensional model is employed. Ionization frequency based on Townsend ionization coefficient is employed in this model. A try-and-error method is employed to estimate the value of each coefficient, and the calculated waveform is compared with the measured current waveform. The values by which the most similar current waveform to the measurement is obtained are selected as appropriate values. Using these coefficient values, the discharge current waveforms by the applying voltage with triangular waveform and trapezoidal waveforms are calculated and compared with the measured current waveforms. Good agreements between the calculation and the measurement in discharge current waveform are obtained for three types of applied voltage waveform. Then, the distributions of electric field, electron density and ion density in the discharge space are calculated. It is shown that the space charge layer is formed on the glass tube wall and ionization takes place mainly in the space charge layer. Professor

  3. Gas filled detectors

    International Nuclear Information System (INIS)

    The main types of gas filled nuclear detectors: ionization chambers, proportional counters, parallel-plate avalanche counters (PPAC) and microstrip detectors are described. New devices are shown. A description of the processes involved in such detectors is also given. (K.A.) 123 refs.; 25 figs.; 3 tabs

  4. Investigation of prototype gas-filled photomultipliers

    International Nuclear Information System (INIS)

    Parallel-plate gas gain of more than 7000 has been observed in a methane-filled low pressure hexode with a semi-transparent photocathode. The photocathode lifetime has been studied in a similarly constructed phototetrode. Conclusions are drawn for the development of future higher gain devices for use in particle physics experiments in high magnetic fields. (author)

  5. Operation of a Thick Gas Electron Multiplier (THGEM) in Ar, Xe and Ar-Xe

    International Nuclear Information System (INIS)

    We present the results of our recent studies of a Thick Gaseous Electron Multiplier (THGEM)-based detector, operated in Ar, Xe and Ar:Xe (95:5) at various gas pressures. Avalanche-multiplication properties and energy resolution were investigated with soft x-rays for different detector configurations and parameters. Gains above 104 were reached in a double-THGEM detector, at atmospheric pressure, in all gases, in almost all the tested conditions; in Ar:Xe (95:5) similar gains were reached at pressures up to 2 bar. The energy resolution dependence on the gas, pressure, hole geometry and electric fields was studied in detail, yielding in some configurations values below 20% FWHM with 5.9 keV x-rays

  6. Innovations in gas filled ionisation chambers

    International Nuclear Information System (INIS)

    The gas filled parallel plate ion chamber and coaxial cylindrical ion chambers are widely used for detection of nuclear radiations for more than hundred years. Thin Metal electrodes or metal coated planes are used as cathode and anodes in both parallel plate and cylindrical ionization chambers since its invention. For neutral particle detection, either the ionising medium or a coated electrode surface is used as a converter material for producing secondary charged particles which are detected in these ionisation chambers. Boron, and 235U are coated as thin layer on the cathode surface with optimum thickness to give maximum neutron detection sensitivity. The neutron sensitivity mostly depends upon the coated surface area and to enhance the neutron sensitivity diameter and the length/ diameter of the coated electrodes have to be increased which also results in an increase in the volume of the counter. For many applications, it is necessary to reduce the size of the counter by a factor of 2 to 5 but having the same efficiency. Recently this has been achieved by designing a non planar electrode surface/ s which has surface area larger by a factor or up to five keeping the external dimensions the same. By using this new technique, it is possible to increase the coated area up to 5 times, without changing the overall dimensions of the counter both for proportional counters and ion chambers. The three methods have been developed to enhance the neutron sensitivity the use of: additional coated wires, coated baffles, coated fins: in sensitive volume of gas detectors. The introduction of these three-dimensional boron coated structures into the sensitive volume without enlarging the outer detector dimensions increases the Boron/Uranium content in the sensitive region without any significant change in the nature of the pulses from these counters. In the newly developed Wire Plane Chambers both in the DC mode and pulse mode, wire planes have been used as anode and cathodes with

  7. Electron cloud sizes in gas-filled detectors

    International Nuclear Information System (INIS)

    Electron cloud sizes have been calculated for gas mixtures containing Ar, Xe, CO2, CH4, and N2 for drifts through a constant electric field. The transport coefficients w and D/μ are in good agreement with experimental data of various sources for pure gases. Results of measurements, also performed in this work, for Ar+CO2, Ar+CH4, and Ar+Xe+CO2 mixtures are in fair agreement with the calculated cloud sizes. For a large number of useful gas mixtures calculated electron cloud sizes are presented and discussed, most of which are given for the first time. A suggestion is made for an optimal gas mixture for an X-ray position sensitive proportional counter for medium and low energies. (orig.)

  8. Evolution of gas-filled nanocracks in crystalline solids

    OpenAIRE

    M. Hartmann; Trinkaus, H.

    2002-01-01

    In this work, the evolution of gas-filled cracks under gas implantation and subsequent annealing is studied on the basis of an elastic continuum approach. The observed growth limitation of He-filled nanocracks in SiC is attributed to their stabilization by the formation of circular dislocation dipoles. The formation and Ostwald ripening of bubble-loop complexes at elevated temperatures is modeled in terms of gas atom exchange between such complexes coupled. with local matrix atom exchange bet...

  9. Gas-filled hohlraum study on Shenguang-III prototype

    Science.gov (United States)

    Yang, Dong; Li, Sanwei; Li, Zhichao; Yi, Rongqing; Guo, Liang; Jiang, Xiaohua; Liu, Shenye; Yang, Jiamin; Jiang, Shaoen; Ding, Yongkun; Hao, Liang; Zhang, Huasen; Zhao, Yiqing; Zou, Shiyang; Huo, Wenyi; Li, Xin

    2015-11-01

    Experimental studies on gas-filled hohlraum were performed extensively in recent years on Shenguang-III prototype laser facility. These experiments employed Au hohlraums within C5H12 gas fill heated by smoothing beams. In the first round of experiments, although the low-Z gas fill impeded the blow-off plasma ablated from hohlraum wall, the x-ray flux from the LEH decreased dramatically compared with the vacuum hohlraum. Further analysis of several ways of energy deposition including heating the gas-fill, extra scattered light and ablating the LEH membrane, revealed that too much laser energy were wasted in exploding the LEH membrane if we use a 1 ns square pulse. After we introduced a low power prepulse to intentionally exploding the membrane, the behavior of the x-ray flux from the gas-filled hohlraum is identical with the vacuum hohlraum. In subsequent studies, the motion of x-ray spot and corona plasma has also been studied using the gas-filled hohlraum. We obtained high quality data of the gas/wall interface and the boundary of the ablated wall near the LEH. The result agrees with that in simulation. However, there is a discrepancy between the experiment and the simulation in the spatial feature of the ablated wall near the LEH extracted from M-band x-ray image.

  10. Flat-top phase-matched high-order harmonics in gas-filled cell

    Institute of Scientific and Technical Information of China (English)

    Xinhua Xie(谢新华); Zhinan Zeng(曾志男); Ruxin Li(李儒新); Yunpei Deng(邓蕴沛); Haihe Lu(陆海鹤); Dingjun Yin(印定军); Zhizhan Xu(徐至展)

    2004-01-01

    Phase-matched high-order harmonic generation in Ar gas-filled cell is investigated experimentally. We obtain phase-matched 27th order harmonic driven by a commercially available solid-state femtosecond laser system at 0.55 m J/pulse energy level and 1-kHz repetition rate. Moreover, we find that the spatial distribution of intensity of high-order harmonics is flat-top profile other than a Gaussian one under the condition of optimized conversion efficiency in the static gas cell.

  11. Gas-Filled-Capillary Discharge Experiment

    Czech Academy of Sciences Publication Activity Database

    Schmidt, Jiří; Koláček, Karel; Frolov, Oleksandr; Prukner, Václav; Štraus, Jaroslav; Sobota, Jaroslav; Fořt, Tomáš

    Washington, DC: IEEE, 2010, s. 707-709. (IEEE Xplore). ISBN 978-1-4244-4064-1. [IEEE International Pulsed Power Conference/17th./. Washington, D.C. (US), 28.06.2010-02.07.2010] R&D Projects: GA MŠk(CZ) LC528; GA MŠk LA08024; GA AV ČR KJB100430702; GA AV ČR KAN300100702 Institutional research plan: CEZ:AV0Z20430508; CEZ:AV0Z20650511 Keywords : Capillary discharge * x-ray * laser Subject RIV: BL - Plasma and Gas Discharge Physics http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5386405

  12. Gas-Filled-Capillary Discharge Experiment

    Czech Academy of Sciences Publication Activity Database

    Schmidt, Jiří; Koláček, Karel; Frolov, Oleksandr; Prukner, Václav; Štraus, Jaroslav

    Vol. IEEE Catalog Number: CFP09PPC. Piscataway : Institute of Electrical and Electronics Engineers, Inc, 2009. s. 245-245. ISBN 978-1-4244-4065-8. [IEEE International Pulsed Power Conference/17th./. 28.06.2009-02.07.2009, Washington, D.C.] R&D Projects: GA MŠk LA08024; GA AV ČR KJB100430702; GA AV ČR KAN300100702; GA MŠk(CZ) LC528 Institutional research plan: CEZ:AV0Z20430508 Keywords : Capillary discharge * x-ray * laser Subject RIV: BL - Plasma and Gas Discharge Physics http://ppc.missouri.edu/Abstracts.pdf

  13. Analysis of tubes filled with charged electron gas

    OpenAIRE

    Karrmann, Stefan

    2011-01-01

    We show that tubes filled with electron gas, as presented by A.Bolonkin, are not possible with current materials. First, the pressure of the charges on the outer surface cancel almost all of the electrostatic pressure of the inner electrons. Second, due to the mutually repulsion most of the electrons are in the outmost shell of the tube and not individually free.

  14. Comparison of scintillation and gas filled detectors for contamination monitoring

    International Nuclear Information System (INIS)

    There are now for radioactive contamination monitoring not only instruments with gas filled detectors but also devices with scintillation detectors in use. These detection techniques have significant physical differences and utilize hardware with specific properties. Therefore there are special advantages and drawbacks for the user and the application. A scintillator is usually a rugged component with a relatively low weight and high detection efficiency. The technical problems with scintillators are mainly in effective and uniform light detection. Gas filled detectors have good uniformities in detection efficiencies. Their main disadvantages are the gas supply and thin entrance windows. These foils can easily be damaged resulting in gas leakage. For both types of instruments efficiencies, typical background levels, position dependent responses and minimum detectable activities for a wide range of radionuclides are summarized and discussed. Also other handling features, like for instance weight, temperature ranges and aspects of service and maintenance are discussed. In addition to the presented data characterizing the different types of contamination monitors it is also important to think about service and maintenance. In general gas filled detectors could more easily be destroyed than scintillators. On an average this generates more problems and also higher repair cost. This is certainly one of the reasons that made scintillators in contamination monitoring so popular. Scintillation detection has been proven to be a reliable and competitive technology for contamination monitoring. The efficiencies and detection limits are in general superior to comparable gas filled detectors. This is also true for many nuclear medicine nuclides with photon emitters. Simultaneous and separate measurement of alpha- and beta-gamma radiation can easily be achieved by pulse analysis. The overall weight of a scintillation based instrument can be substantially lower than the weight of

  15. Principles of a gas filled magnetic spectrometer for fission studies

    International Nuclear Information System (INIS)

    The spectroscopy of the prompt gamma decay from fission products gives information on the entry states, e.g. distribution functions for excitation energy and spin, and therefore a direct link to the fission process itself. This type of spectroscopy is, however, only possible when a filter can be constructed which allows setting a gate to the gamma-spectrum in a narrow region in mass and nuclear charge, as well as on the total excitation energy of the fragment split under investigation. A possible configuration of a prompt gamma-ray spectrometer consist of a gamma-ray array composed of high resolution germanium detectors, coupled to a gas filled magnet. We will outline the principles for a gas filled magnetic spectrometer for fission product spectroscopy. In particular the focusing characteristics of such a device, which are valid for particles in the velocity regime of E/A< 1 MeV/amu, will be addressed. First experiments on the LOHENGRIN spectrometer in Grenoble investigating on the behavior of fission products in gas filled magnets have been performed, and have validated the experimental approach to the nuclear fission process with such a device. (authors)

  16. Principles of a gas filled magnetic spectrometer for fission studies

    Directory of Open Access Journals (Sweden)

    Faust H.

    2013-12-01

    Full Text Available The spectroscopy of the prompt gamma decay from fission products gives information on the entry states, e.g. distribution functions for excitation energy and spin, and therefore a direct link to the fission process itself. This type of spectroscopy is, however, only possible when a filter can be constructed which allows setting a gate to the gamma-spectrum in a narrow region in mass and nuclear charge, as well as on the total excitation energy of the fragment split under investigation. A possible configuration of a prompt gamma-ray spectrometer consist of a gamma-ray array composed of high resolution germanium detectors, coupled to a gas filled magnet. We will outline the principles for a gas filled magnetic spectrometer for fission product spectroscopy. In particular the focusing characteristics of such a device, which are valid for particles in the velocity regime of E/A< 1MeV/amu, will be addressed. First experiments on the LOHENGRIN spectrometer in Grenoble investigating on the behavior of fission products in gas filled magnets have been performed, and have validated the experimental approach to the nuclear fission process with such a device.

  17. Systems and methods for regulating pressure of a filled-in gas

    Energy Technology Data Exchange (ETDEWEB)

    Stautner, Ernst Wolfgang; Michael, Joseph Darryl

    2016-05-03

    A system for regulating a pressure of a filled-in gas is presented. The system includes a reservoir that stores a reservoir gas adsorbed in a sorbent material at a storage temperature, a gas-filled tube containing the filled-in gas, a controller configured to determine a pressure change required in the filled-in gas based upon signals representative of a pressure of the filled-in gas inside the gas-filled tube and a required pressure threshold, determine an updated temperature of the sorbent material based upon the pressure change required in the filled-in gas, and regulate the pressure of the filled-in gas by controlling the reservoir to change the storage temperature of the sorbent material to reach the updated temperature of the sorbent material.

  18. Polysulfone hollow fiber gas separation membranes filled with submicron particles.

    Science.gov (United States)

    Bhardwaj, V; Macintosh, A; Sharpe, I D; Gordeyev, S A; Shilton, S J

    2003-03-01

    Three different fillers, carbon black (CB), vapor grown carbon fibers (VGCF), and TiO(2), were incorporated into polysulfone spinning solutions with the intention of producing highly selective membranes with enhanced mechanical strength. The effect of filler presence on gas permeation characteristics, mechanical strength (bursting pressure), and morphology was investigated and compared to unfilled membranes. As well as studying filler types, the influence of CB filler concentration on membrane performance was also examined. For all filler types (at a concentration of 5%w/w), the pressure-normalized flux of O(2), N(2), and CH(4) was greater in the composite than in the unfilled membranes. The CO(2) pressure-normalized flux was only greater in the TiO(2) composite membranes. For CB and VGCF, the CO(2) pressure-normalized flux was reduced compared with unfilled membranes. Three CB concentrations were investigated (2, 5, and 10%w/w). For O(2), N(2), and CH(4), pressure-normalized flux peaked at 5%w/w CB. CO(2) exhibited the opposite trend, showing a minimum pressure-normalized flux at 5%w/w. Considering O(2)/N(2) and CO(2)/CH(4) gas pairs and the various filled membrane categories, only the O(2)/N(2) selectivity of the 2%w/w CB filled membranes was higher than that of the unfilled fibers-all other selectivities were lower. In terms of CB concentration, selectivity was a minimum at the intermediate concentration of 5%w/w. All the filled membrane types exhibited greater mechanical strength (bursting pressure) than unfilled fibers apart from the 5%w/w VGCF composites. The 2%w/w CB composites were the strongest. Electron microscopy showed no visible differences in general morphology between the various filled and unfilled membranes. PMID:12783827

  19. Monte Carlo simulation of gas-filled radiation detectors

    International Nuclear Information System (INIS)

    A new simulation code has been developed that allows the response of gas-filled proportional counters to be calculated. The code is an electron transport code that simulates the elastic and inelastic scattering processes that occur as a result of electron-impact collisions with the gas atoms. The simulation concentrates on the avalanche development after the primary ionising particle has freed electrons in the gas volume, by tracking electrons until they reach the anode of the counter. The dynamics of the ions that accumulate in the gas volume are also considered. A major motivation for this work is the general renewed interest in proportional counters over the last decade, since the advent of micro-pattern detectors such as the micro-strip and the micro-gap detector. It is argued that the low relative cost, intrinsic amplification and environmental stability of these detectors gives them considerable advantages over other types of radiation detectors. The code has been benchmarked against experimental data. The manner in which the variation in the avalanche statistics affects the energy resolution properties of the detector is examined for single wire counters, micro-strip and micro-gap counters. The stability of micro-gap detectors when subjected to high rates of irradiation is also examined. It is envisaged that these detectors will be used in the future as part of a multiphase flow tomography device for imaging the flow of oil/water/natural gas mixtures that have been pumped through pipes from the seabed. (author)

  20. Polystyrene foam products equation of state as a function of porosity and fill gas

    Energy Technology Data Exchange (ETDEWEB)

    Mulford, Roberta N [Los Alamos National Laboratory; Swift, Damian C [LLNL

    2009-01-01

    An accurate EOS for polystyrene foam is necessary for analysis of numerous experiments in shock compression, inertial confinement fusion, and astrophysics. Plastic to gas ratios vary between various samples of foam, according to the density and cell-size of the foam. A matrix of compositions has been investigated, allowing prediction of foam response as a function of the plastic-to-air ratio. The EOS code CHEETAH allows participation of the air in the decomposition reaction of the foam. Differences between air-filled, Ar-blown, and CO{sub 2}-blown foams are investigated, to estimate the importance of allowing air to react with products of polystyrene decomposition. O{sub 2}-blown foams are included in some comparisons, to amplify any consequences of reaction with oxygen in air. He-blown foams are included in some comparisons, to provide an extremum of density. Product pressures are slightly higher for oxygen-containing fill gases than for non-oxygen-containing fill gases. Examination of product species indicates that CO{sub 2} decomposes at high temperatures.

  1. Handbook for Gas Filled RF Cavity Aficionados'

    Energy Technology Data Exchange (ETDEWEB)

    Tollestrup, A.V.; Chung, Moses; Yonehara, Katsuya; /Fermilab

    2009-05-01

    The use of hydrogen gas filled RF cavities in muon cooling channels has been proposed by Rolland Johnson. Impressive results have been obtained toward attaining high voltage gradients and rapid training in preliminary tests done at the FNAL MTA facility. However, so far it has not been possible to test them under conditions where they were subject to the transversal of a high intensity particle beam. This note is an attempt to bring together a description of some of the pertinent physical processes that take place in the dilute plasma that is generated in the hydrogen gas by the beam. Two effects dominate. The first is that the free electrons generated can load down the cavity and transfer its energy to heating the gas. The second is a question of what happens to the plasma in the longer term. There is an enormous literature on the subject of the subject of dilute hydrogen plasmas and we can tap into this information in order to understand and predict the behavior of the cavity.

  2. Development of a portable gas-filled ionization chamber

    Science.gov (United States)

    Chae, K. Y.; Cha, S. M.; Gwak, M. S.

    2014-02-01

    A new portable gas-filled ionization chamber has been designed and constructed at the Physics Department of Sung Kyun Kwan University. To overcome the maximum count rate of ˜105 particles per second of a conventional ionization chamber, which utilizes a Frisch grid, and to enhance the portability of a detector, we adopted the design of multiple electrodes and modified it from the original designs by Kimura et al. and Chae et al. The new design utilizes a stack of multiple electrodes installed perpendicular to the optical beam axis. This configuration provides a fast response time for the detector, which is essential for high-rate counting. The device has been tested with a 241Am ( t 1/2 = 432.2 years) radioactive α source, which mainly emits 5.486-MeV (branching ratio of 85%) and 5.443-MeV (branching ratio of 13%) α particles. An energy resolution of 6.3% was achieved.

  3. Development of a portable gas-filled ionization chamber

    International Nuclear Information System (INIS)

    A new portable gas-filled ionization chamber has been designed and constructed at the Physics Department of Sung Kyun Kwan University. To overcome the maximum count rate of ∼ 105 particles per second of a conventional ionization chamber, which utilizes a Frisch grid, and to enhance the portability of a detector, we adopted the design of multiple electrodes and modified it from the original designs by Kimura et al. and Chae et al. The new design utilizes a stack of multiple electrodes installed perpendicular to the optical beam axis. This configuration provides a fast response time for the detector, which is essential for high-rate counting. The device has been tested with a 241Am (t1/2 = 432.2 years) radioactive α source, which mainly emits 5.486-MeV (branching ratio of 85%) and 5.443-MeV (branching ratio of 13%) α particles. An energy resolution of 6.3% was achieved.

  4. A compact gas-filled avalanche counter for DANCE

    International Nuclear Information System (INIS)

    A compact gas-filled avalanche counter for the detection of fission fragments was developed for a highly segmented 4π γ-ray calorimeter, namely the Detector for Advanced Neutron Capture Experiments located at the Lujan Center of the Los Alamos Neutron Science Center. It has been used successfully for experiments with 235U, 238Pu, 239Pu, and 241Pu isotopes to provide a unique signature to differentiate the fission from the competing neutron-capture reaction channel. It was also used to study the spontaneous fission in 252Cf. The design and performance of this avalanche counter for targets with extreme α-decay rate up to ∼2.4×108/s are described.

  5. High pressure gas-filled cermet spark gaps

    International Nuclear Information System (INIS)

    The results of modernization of the R-48 and R-49 spark gaps making it possible to improve their electrical characteristics are presented. The design is described and characteristics of gas-filled cermet spark gaps are presented. By the voltage rise time of 5-6 μs in the Marx generator scheme they provide for the pulse break-through voltage of 120 and 150 kV. By the voltage rise time of 0.5-1 μs the break-through voltage of these spark gaps may be increased up to 130 and 220 kV. The proper commutation time is equal to ≤ 0.5 ns. Practical recommendations relative to designing cermet spark gaps are given

  6. A compact gas-filled avalanche counter for DANCE

    Science.gov (United States)

    Wu, C. Y.; Chyzh, A.; Kwan, E.; Henderson, R. A.; Gostic, J. M.; Carter, D.; Bredeweg, T. A.; Couture, A.; Jandel, M.; Ullmann, J. L.

    2012-12-01

    A compact gas-filled avalanche counter for the detection of fission fragments was developed for a highly segmented 4π γ-ray calorimeter, namely the Detector for Advanced Neutron Capture Experiments located at the Lujan Center of the Los Alamos Neutron Science Center. It has been used successfully for experiments with 235U, 238Pu, 239Pu, and 241Pu isotopes to provide a unique signature to differentiate the fission from the competing neutron-capture reaction channel. It was also used to study the spontaneous fission in 252Cf. The design and performance of this avalanche counter for targets with extreme α-decay rate up to ˜2.4×108/s are described.

  7. A compact gas-filled avalanche counter for DANCE

    Energy Technology Data Exchange (ETDEWEB)

    Wu, C.Y., E-mail: wu24@llnl.gov [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Chyzh, A.; Kwan, E.; Henderson, R.A.; Gostic, J.M.; Carter, D. [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Bredeweg, T.A.; Couture, A.; Jandel, M.; Ullmann, J.L. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2012-12-01

    A compact gas-filled avalanche counter for the detection of fission fragments was developed for a highly segmented 4{pi} {gamma}-ray calorimeter, namely the Detector for Advanced Neutron Capture Experiments located at the Lujan Center of the Los Alamos Neutron Science Center. It has been used successfully for experiments with {sup 235}U, {sup 238}Pu, {sup 239}Pu, and {sup 241}Pu isotopes to provide a unique signature to differentiate the fission from the competing neutron-capture reaction channel. It was also used to study the spontaneous fission in {sup 252}Cf. The design and performance of this avalanche counter for targets with extreme {alpha}-decay rate up to {approx}2.4 Multiplication-Sign 10{sup 8}/s are described.

  8. Alteration of natural (37)Ar activity concentration in the subsurface by gas transport and water infiltration.

    Science.gov (United States)

    Guillon, Sophie; Sun, Yunwei; Purtschert, Roland; Raghoo, Lauren; Pili, Eric; Carrigan, Charles R

    2016-05-01

    High (37)Ar activity concentration in soil gas is proposed as a key evidence for the detection of underground nuclear explosion by the Comprehensive Nuclear Test-Ban Treaty. However, such a detection is challenged by the natural background of (37)Ar in the subsurface, mainly due to Ca activation by cosmic rays. A better understanding and improved capability to predict (37)Ar activity concentration in the subsurface and its spatial and temporal variability is thus required. A numerical model integrating (37)Ar production and transport in the subsurface is developed, including variable soil water content and water infiltration at the surface. A parameterized equation for (37)Ar production in the first 15 m below the surface is studied, taking into account the major production reactions and the moderation effect of soil water content. Using sensitivity analysis and uncertainty quantification, a realistic and comprehensive probability distribution of natural (37)Ar activity concentrations in soil gas is proposed, including the effects of water infiltration. Site location and soil composition are identified as the parameters allowing for a most effective reduction of the possible range of (37)Ar activity concentrations. The influence of soil water content on (37)Ar production is shown to be negligible to first order, while (37)Ar activity concentration in soil gas and its temporal variability appear to be strongly influenced by transient water infiltration events. These results will be used as a basis for practical CTBTO concepts of operation during an OSI. PMID:26939033

  9. 40Ar/39Ar dating of Quaternary volcanic ashes by multi-collection noble gas mass spectrometry: protocols, precision and intercalibration

    DEFF Research Database (Denmark)

    Storey, Michael; Rivera, Tiffany; Flude, Stephanie;

    where potassium-bearing phenocrysts may contain relatively small amounts of radiogenic 40Ar. In 2005, the Quaternary Dating Laboratory, Roskilde University, installed a Nu-Instruments multi-collector Noblesse noble gas mass spectrometer, which is configured with a Faraday detector and three ion......The recent availability of commercial high-resolution, multi-collector, noble gas mass spectrometers equipped with ion-counting electron multipliers provides new opportunities for improved precision in 40Ar/39Ar dating. This is particularly true for single crystal dating of Quaternary aged samples...... for single crystal 40Ar/39Ar dating of Quaternary samples because of: (i) improved source sensitivity; (ii) ion-counting electron multipliers, which have low signal to noise ratios enabling precise measurement of very small 36Ar signals - resulting in accurate correction for atmospheric-derived 40Ar; (iii...

  10. Laser-plasma interactions in large gas-filled hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Turner, R.E.; Powers, L.V.; Berger, R.L. [and others

    1996-06-01

    Indirect-drive targets planned for the National Ignition Facility (NIF) laser consist of spherical fuel capsules enclosed in cylindrical Au hohlraums. Laser beams, arranged in cylindrical rings, heat the inside of the Au wall to produce x rays that in turn heat and implode the capsule to produce fusion conditions in the fuel. Detailed calculations show that adequate implosion symmetry can be maintained by filling the hohlraum interior with low-density, low-Z gases. The plasma produced from the heated gas provides sufficient pressure to keep the radiating Au surface from expanding excessively. As the laser heats this gas, the gas becomes a relatively uniform plasma with small gradients in velocity and density. Such long-scale-length plasmas can be ideal mediums for stimulated Brillouin Scattering (SBS). SBS can reflect a large fraction of the incident laser light before it is absorbed by the hohlraum; therefore, it is undesirable in an inertial confinement fusion target. To examine the importance of SBS in NIF targets, the authors used Nova to measure SBS from hohlraums with plasma conditions similar to those predicted for high-gain NIF targets. The plasmas differ from the more familiar exploding foil or solid targets as follows: they are hot (3 keV); they have high electron densities (n{sub e}=10{sup 21}cm{sup {minus}3}); and they are nearly stationary, confined within an Au cylinder, and uniform over large distances (>2 mm). These hohlraums have <3% peak SBS backscatter for an interaction beam with intensities of 1-4 x 10{sup 15} W/cm{sup 2}, a laser wavelength of 0.351{micro}m, f/4 or f/8 focusing optics, and a variety of beam smoothing implementations. Based on these conditions the authors conclude that SBS does not appear to be a problem for NIF targets.

  11. Theoretical rovibrational analysis of the covalent noble gas compound ArNH+

    Science.gov (United States)

    Novak, Carlie M.; Fortenberry, Ryan C.

    2016-04-01

    Noble gasses can make covalent bonds. This has been clearly shown for ArH+ as is evidenced by the observation of this molecule ubiquitously in the interstellar medium. In order to augment the list of potential noble gas molecules, highly-accurate quartic field methods are employed here to analyze the ArNH+ radical cation for the first time. This study is in line with previous examinations of ArOH+, ArH2+, and ArH3+. It is shown here that the Arsbnd N bond strength falls below the Arsbnd O bond energy in ArOH+ but in line with that from ArH2+ indicating that ArNH+ could certainly be synthesized in the lab or, potentially, in nature. In order to aid in the search for this noble gas molecular cation, spectroscopic constants, fundamental vibrational frequencies, absorption intensities, and the center-of-mass dipole moment are provided at high-level in order to augment our understanding of noble gas chemistry.

  12. Composition of Ar-Kr, Kr-Xe, and N2-Ar clusters produced by supersonic expansion of gas mixtures

    CERN Document Server

    Konotop, O P; Danylchenko, O G; Samovarov, V N

    2014-01-01

    An electron-diffraction study is made of the composition of binary Ar-Kr, Kr-Xe, and N2-Ar clusters of various size produced by expansion through a supersonic nozzle of gas mixtures with various component concentrations. The resulting clusters are shown to have compositions substantially different from those of the primary gas mixtures and dependent on cluster size. We have found that the key parameters needed for an analysis of cluster composition are the critical cluster radius and the heavier component concentration in the gas mixture which can be used to establish the regions of existence of homogeneous and heterogeneous clusters. These critical values determine the coefficient of the enrichment of clusters with the heavier component with respect to its concentration in the primary gas mixture. Theoretical relations are obtained which provide a good quantitative description of the experimental results and can be expected to be also valid for finding the composition of binary clusters of other van der Waal...

  13. Gas phase chemical studies of superheavy elements using the Dubna gas-filled recoil separator - Stopping range determination

    International Nuclear Information System (INIS)

    Currently, gas phase chemistry experiments with heaviest elements are usually performed with the gas-jet technique with the disadvantage that all reaction products are collected in a gas-filled thermalisation chamber adjacent to the target. The incorporation of a physical preseparation device between target and collection chamber opens up the perspective to perform new chemical studies. But this approach requires detailed knowledge of the stopping force (STF) of the heaviest elements in various materials. Measurements of the energy loss of mercury (Hg), radon (Rn), and nobelium (No) in Mylar and argon (Ar) were performed at low kinetic energies of around (40-270) keV per nucleon. The experimentally obtained values were compared with STF calculations of the commonly used program for calculating stopping and ranges of ions in matter (SRIM). Using the obtained data points an extrapolation of the STF up to element 114, eka-lead, in the same stopping media was carried out. These estimations were applied to design and to perform a first chemical experiment with a superheavy element behind a physical preseparator using the nuclear fusion reaction 244Pu(48Ca; 3n)289114. One decay chain assigned to an atom of 285112, the α-decay product of 289114, was observed.

  14. Efficient Spectral Broadening in the 100-W Average Power Regime Using Gas Filled Kagome HC-PCF and Pulse Compression

    OpenAIRE

    Emaury, Florian; Saraceno, Clara J.; Debord, Benoit; Ghosh, Debashri; Diebold, Andreas; Gerome, Frederic; Suedmeyer, Thomas; Benabid, Fetah; Keller, Ursula

    2014-01-01

    We present nonlinear pulse compression of a high-power SESAM-modelocked thin-disk laser (TDL) using an Ar-filled hypocycloid-core Kagome Hollow-Core Photonic Crystal Fiber (HC-PCF). The output of the modelocked Yb:YAG TDL with 127 W average power, a pulse repetition rate of 7 MHz, and a pulse duration of 740 fs was spectrally broadened 16-fold while propagating in a Kagome HC-PCF containing 13 bar of static Argon gas. Subsequent compression tests performed using 8.4% of the full available pow...

  15. Automation of experiments at Dubna Gas-Filled Recoil Separator

    Science.gov (United States)

    Tsyganov, Yu. S.

    2016-01-01

    Approaches to solving the problems of automation of basic processes in long-term experiments in heavy ion beams of the Dubna Gas-Filled Recoil Separator (DGFRS) facility are considered. Approaches in the field of spectrometry, both of rare α decays of superheavy nuclei and those for constructing monitoring systems to provide accident-free experiment running with highly radioactive targets and recording basic parameters of experiment, are described. The specific features of Double Side Silicon Strip Detectors (DSSSDs) are considered, special attention is paid to the role of boundary effects of neighboring p-n transitions in the "active correlations" method. An example of an off-beam experiment attempting to observe Zeno effect is briefly considered. Basic examples for nuclear reactions of complete fusion at 48Ca ion beams of U-400 cyclotron (LNR, JINR) are given. A scenario of development of the "active correlations" method for the case of very high intensity beams of heavy ions at promising accelerators of LNR, JINR, is presented.

  16. Development of a portable gas-filled ionization chamber

    Energy Technology Data Exchange (ETDEWEB)

    Chae, K. Y.; Cha, S. M.; Gwak, M. S. [Sungkyunkwan University, Suwon (Korea, Republic of)

    2014-02-15

    A new portable gas-filled ionization chamber has been designed and constructed at the Physics Department of Sung Kyun Kwan University. To overcome the maximum count rate of ∼ 10{sup 5} particles per second of a conventional ionization chamber, which utilizes a Frisch grid, and to enhance the portability of a detector, we adopted the design of multiple electrodes and modified it from the original designs by Kimura et al. and Chae et al. The new design utilizes a stack of multiple electrodes installed perpendicular to the optical beam axis. This configuration provides a fast response time for the detector, which is essential for high-rate counting. The device has been tested with a {sup 241}Am (t{sub 1/2} = 432.2 years) radioactive α source, which mainly emits 5.486-MeV (branching ratio of 85%) and 5.443-MeV (branching ratio of 13%) α particles. An energy resolution of 6.3% was achieved.

  17. The influence of argon-ethanol and argon-bromine main filling gas pressure on the performance of Geiger-Mueller Detector

    International Nuclear Information System (INIS)

    It has been research on the influence of Ar-ethanol and Ar-Br. Filled as pressure on the performance of Geiger-Mueller detector. The Geiger-Mueller detector tube is made of stainless steel with diameter of 1.6 cm, anode is made of tungsten wire of 0.008 cm in diameter, the length of active media is 10 cm and density thickness window 0.39 g/cm2. The pressure of Ar-ethanol as filling gas were varied i.e 7:1, 9:1, and 19:1 respectively, while the ratio of pressure between Ar-Br is 100:1; 50:1 and 33:1. The test result shows that the best result is obtained at ratio between Ar-ethanol 9:1, the length of plateau is 180 V, slope is 9.60 %/100 V, resolving time is 6,725 µS and operating voltage is 1,160 V. Meanwhile, Br as quenching in the ratio of 100:1, the length of plateau is 100 V, the slope is 7.68 %/100 V, the resolving time 7.75 µS and operating voltage is 540 V. In this research, the detector life time can not be predicted because the detector during the process of testing and still has a long plateau and the pulse shape non discharged. The number of counting resulted from the detector with Ar-ethanol as filling gas is 3,105 ×106 counts, while for Ar-Br is 1,102 ×107 counts. (author)

  18. Experimental Study of High-Z Gas Buffers in Gas-Filled ICF Engines

    Energy Technology Data Exchange (ETDEWEB)

    Rhodes, M A; Kane, J; Loosmore, G; DeMuth, J; Latkowski, J

    2010-12-03

    ICF power plants, such as the LIFE scheme at LLNL, may employ a high-Z, target-chamber gas-fill to moderate the first-wall heat-pulse due to x-rays and energetic ions released during target detonation. To reduce the uncertainties of cooling and beam/target propagation through such gas-filled chambers, we present a pulsed plasma source producing 2-5 eV plasma comprised of high-Z gases. We use a 5-kJ, 100-ns theta discharge for high peak plasma-heating-power, an electrode-less discharge for minimizing impurities, and unobstructed axial access for diagnostics and beam (and/or target) propagation studies. We will report on the plasma source requirements, design process, and the system design.

  19. A Concept for a Low Pressure Noble Gas Fill Intervention in the IFE Fusion Test Facility (FTF) Target Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Gentile, C. A.; Blanchard, W. R.; Kozub, T. A.; Aristova, M.; McGahan, C.; Natta, S.; Pagdon, K.; Zelenty, J.

    2010-01-14

    wall acts as the primary heat exchanger. During removal, gas is pumped through the laser ports by turbo molecular-drag pumps (TM-DP). For the purpose of reducing organic based lubricants and seals, a magnetically levitated TM-DP is being investigated with pump manufacturers. Currently, magnetically levitated turbo molecular pumps are commercially available. The pumps will be exposed to thermal loads and ionizing radiation (tritium, Ar-41, post detonation neutrons). Although the TM-DP's will be subjected to these various radiations, current designs for similar pumping devices have been hardened and have the ability of locating control electronics in remote radiation shielded enclosures4. The radiation hardened TM-DP's will be 5 required to operate with minimal maintenance for periods of up to 18 continuous months. As part of this initial investigation for developing a conceptual engineering strategy for a gas fill solution, commercial suppliers of low pressure gas pumping systems have been contacted and engaged in this evaluation. Current technology in the area of mechanical pumping systems indicates that the development of a robust pumping system to meet the requirements of the FTF gas fill concept is within the limits of COTS equipment3,4.

  20. A Concept for a Low Pressure Noble Gas Fill Intervention in the IFE Fusion Test Facility (FTF) Target Chamber

    International Nuclear Information System (INIS)

    wall acts as the primary heat exchanger. During removal, gas is pumped through the laser ports by turbo molecular-drag pumps (TM-DP). For the purpose of reducing organic based lubricants and seals, a magnetically levitated TM-DP is being investigated with pump manufacturers. Currently, magnetically levitated turbo molecular pumps are commercially available. The pumps will be exposed to thermal loads and ionizing radiation (tritium, Ar-41, post detonation neutrons). Although the TM-DP's will be subjected to these various radiations, current designs for similar pumping devices have been hardened and have the ability of locating control electronics in remote radiation shielded enclosures4. The radiation hardened TM-DP's will be 5 required to operate with minimal maintenance for periods of up to 18 continuous months. As part of this initial investigation for developing a conceptual engineering strategy for a gas fill solution, commercial suppliers of low pressure gas pumping systems have been contacted and engaged in this evaluation. Current technology in the area of mechanical pumping systems indicates that the development of a robust pumping system to meet the requirements of the FTF gas fill concept is within the limits of COTS equipment3,4.

  1. Ultrasound detection in the Gulf menhaden requires gas-filled bullae and an intact lateral line

    DEFF Research Database (Denmark)

    Wilson, Maria; Montie, Eric W.; Mann, Kenneth A.; Mann, David A.

    2009-01-01

    via the lateral recess membrane. It has been hypothesized that the utricle of the inner ear is responsible for ultrasound detection through a specialized connection to the gas-filled bullae complex. Here, we show that the lateral line and its connection to the gas-filled bullae complex via the lateral...... recess are involved in ultrasound detection in Gulf menhaden. Removal of a small portion of the lateral line overlying the lateral recess membrane eliminates the ability of Gulf menhaden to detect ultrasound. We further show that the gas-filled bullae vibrates in response to ultrasound, that the gas......-filled bullae are necessary for detecting ultrasound, and that the bullae connections to the lateral line via the lateral recess membrane play an important role in ultrasound detection. These results add a new dimension to the role of the lateral line and bullae as part of the ultrasonic detection system in...

  2. A combined noble gas and {sup 40}Ar-{sup 39}Ar study of Salt Lake Crater xenolith SL322 from Oahu, Hawaii

    Energy Technology Data Exchange (ETDEWEB)

    Trieloff, M. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Rocholl, A. [Heidelberg Univ. (Germany). Mineralogisch-Petrographisches Inst.; Jessberger, E.K. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)]|[Muenster Univ. (Germany). Inst. fuer Planetologie

    1998-12-31

    The microdistribution of noble gases in a garnet pyroxenite nodule from Salt Lake Crater (SLC), Oahu, Hawaii, was investigated by a detailed step-heating and -crushing analysis and a {sup 40}Ar-{sup 39}Ar-study. A noble gas component with MORB type argon, helium and neon resides in CO{sub 2}-rich fluid inclusions trapped in <30 km depth. This component was most probably derived from the nephelinitic SLC host magma and confirms the dominance of MORB type noble gases in the late post-erosional magmatic stages of Hawaiian volcanism, as suggested previsouly (Kurz et al., 1983; Valbracht et al., 1996). A second previously detected (Rocholl et al., 1996) low {sup 40}Ar/{sup 36}Ar ({proportional_to}5000) component turned out to be associated with two different reservoirs. The larger reservoir is most probably related to garnet, the other one is associated with low retentive sites containing few K and Cl and could not yet be adequately identified. The low {sup 40}Ar/{sup 36}Ar ({proportional_to}5000) component hosted by garnet can be interpreted as a mixture of MORB and plume type noble gas components with specific {sup 4}He/{sup 40}Ar ratios. The results demonstrate the complexity of the microdistribution of noble gases in ultramafic nodules and allow insight into plume induced metasomatism of the Hawaiian lithosphere. (orig.)

  3. Development of data logger for atmospheric pressure, temperature and relative humidity for gas-filled detector

    International Nuclear Information System (INIS)

    At IoP-NISER an initiative has been taken to build and test micro-pattern gas detector such as Gas Electron Multiplier (GEM) for several upcoming High-Energy Physics (HEP) experiment projects. Temperature (t), atmospheric pressure (p) and relative humidity (RH) monitor and recording is very important for gas filled detector development. A data logger to monitor and record the ambient parameters such as temperature, relative humidity and pressure has been developed. With this data logger continuous recording of t, p, RH and time stamp can be done with a programmable sampling interval. This data is necessary to correct the gain of a gas filled detector

  4. Effects of Natural Gas Compositions on CNG Fast Filling Process for Buffer Storage System

    Directory of Open Access Journals (Sweden)

    Farzaneh-Gord M.

    2013-02-01

    Full Text Available The accurate modeling of the fast-fill process occurring in Compressed Natural Gas (CNG fuelled vehicle storage cylinders is a complex process and should be thoroughly studied. Final in-cylinder conditions should meet appropriate cylinder safety standards. The composition of natural gas plays an important role on its thermodynamic properties and consequently, on the fast-fill process and the final conditions. Here, a theoretical analysis has been developed to study the effects of the natural gas composition on the filling process of an onboard Natural Gas Vehicle (NGV cylinder. The cylinder is assumed as a lumped system. The analysis is based on laws of thermodynamics and mass balance. Based on AGA8 Equation of State (EOS and thermodynamics relationships, the required properties of natural gas mixtures have been calculated. The results are presented for an adiabatic system. The results show that the compositions of natural gas have great effects on the filling process and final in-cylinder conditions. Furthermore, the gas with less methane percentage in its composition is more suitable for the filling process.

  5. Detection of a Noble Gas Molecular Ion, {36}ArH^+, in the Crab Nebula

    CERN Document Server

    Barlow, M J; Owen, P J; Cernicharo, J; Gomez, H L; Ivison, R J; Krause, O; Lim, T L; Matsuura, M; Miller, S; Olofsson, G; Polehampton, E T

    2013-01-01

    Noble gas molecules have not hitherto been detected in space. From spectra obtained with the Herschel Space Observatory, we report the detection of emission in the 617.5 GHz and 1234.6 GHz J = 1-0 and 2-1 rotational lines of {36}ArH^+ at several positions in the Crab Nebula, a supernova remnant known to contain both H2 molecules and regions of enhanced ionized argon emission. {36}Ar is believed to have originated from explosive nucleosynthesis in massive stars during core-collapse supernova events. Its detection in the Crab Nebula, the product of such a supernova event, confirms this expectation. The likely excitation mechanism for the observed {36}ArH^+ emission lines is electron collisions in partially ionized regions with electron densities of a few hundred per centimeter cubed.

  6. Method and apparatus for producing gas-filled hollow spheres. [target pellets for inertial confinement fusion

    Science.gov (United States)

    Wang, T. G.; Elleman, D. D. (Inventor)

    1982-01-01

    A system for forming hollow spheres containing pressured gas is described which includes a cylinder device containing a molten solid material with a nozzle at its end. A second gas nozzle, lying slightly upstream from the tip of the first nozzle, is connected to a source that applies pressured filler gas that is to fill the hollow spheres. High pressure is applied to the molten metal, as by moving a piston within the cylinder device, to force the molten material out of the first nozzle. At the same time, pressured gas fills the center of the extruded hollow liquid pipe that breaks into hollow spheres. The environment outside the nozzles contains gas at a high pressure such as 100 atmospheres. Gas is supplied to the gas nozzle at a slightly higher pressure such as 101 atmospheres. The pressure applied to the molten material is at a still higher pressure such as 110 atmospheres.

  7. 78 FR 58604 - Safety Advisory: Unauthorized Filling of Compressed Gas Cylinders

    Science.gov (United States)

    2013-09-24

    ... Gas Cylinders AGENCY: Pipeline and Hazardous Materials Safety Administration (PHMSA), DOT. ACTION... transportation high pressure compressed gas cylinders (DOT Specification 3A, 3AA and 3AL) without verifying that... cylinders without verifying their suitability for continued service. Komer Carbonic Corp. fills and...

  8. 78 FR 42817 - Safety Advisory: Unauthorized Filling of Compressed Gas Cylinders

    Science.gov (United States)

    2013-07-17

    ... Gas Cylinders AGENCY: Pipeline and Hazardous Materials Safety Administration (PHMSA), DOT. ACTION... offered for transportation high pressure compressed gas cylinders without verifying that they met the... DOT 3A 1800 cylinder filled and provided by North American Coil and Beverage Group with carbon...

  9. 40Ar/39Ar total gas ages of basalts from Notera-3 well, Hula Valley, Dead Sea Rift

    International Nuclear Information System (INIS)

    Dating of basalts penetrated in the Notera-3 well in the Hula Valley by the 40Ar/39Ar method in a single, gas extraction reveals a relatively consistent pattern in the section. Using these data a refinement of the stratigraphy for the volcanic units within the Hula Valley and the timing of its development is obtained. Basalts from the depth of 500-1100m have an age of 1.4-1.1 m.y. and are correlated with the Dalwe Basalt known from the slopes of the Golan Heights, with the Yarda Basalt in the Korazim Block, and with the Hasbani Basalt in the southern Lebanon. Basalt from the 1100-1600m interval have an age of 2.7 m.y. and are correlated with the Mechki Basalt in the southern Lebanon and in the Upper Galilee. Basalt from the 1600-2418m interval range in age from 3.2 to 4.1 m.y. and are correlated with the cover basalt as known in the Golan Heights and the Galilee. At a depth of 2427m, a Miocene basalt was encountered (age 8.8 m.y.). Such basalt have not been encountered previously north of the Lower Galilee. The lack of basalts and/or sediments having ages of 8.8-4.1 m.y. indicates that the Hula area was structurally relatively high at that time; thus prior to the Cover Basalt as known in the Hula area did not serve as a morphologic depression. Significant subsidence of the Hula Valley is recognized since Cover Basalt time. It seems that the tectonic phase which led to the formation of the Hula depression as one of the rhomb-shaped garbens along the Rift was initiated 4 m.y. ago. The rate of subsidence of the Hula Valley since its formation is 0.5-0.7 mm/y, which is similar to that estimated from other areas along the Dead Sea Rift. (author)

  10. Na-montmorillonite-filled Polyethersulfone Membranes for Gas Transport

    Czech Academy of Sciences Publication Activity Database

    Wu, J.-W.; Suen, S.-Y.; Petričkovič, Roman; Uchytil, Petr

    -: -, 2009, 183/P5-50/. ISBN N. [Conference of Aseanian Membrane Society /5./. Kobe (JP), 12.07.2009-14.07.2009] R&D Projects: GA ČR GA104/09/1165 Grant ostatní: NSCT(TW) 98-2911-I-005-002 Institutional research plan: CEZ:AV0Z40720504 Keywords : permeability * gas flux * polyethersulfone membranes Subject RIV: CI - Industrial Chemistry, Chemical Engineering http://www.pac.ne.jp/ams5

  11. Beam cooling using a gas-filled RFQ ion guide

    CERN Document Server

    Henry, S; De Saint-Simon, M; Jacotin, M; Képinski, J F; Lunney, M D

    1999-01-01

    A radiofrequency quadrupole mass filter is being developed for use as a high-transmission beam cooler by operating it in buffer gas at high pressure. Such a device will increase the sensitivity of on-line experiments that make use of weakly produced radioactive ion beams. We present simulations and some preliminary measurements for a device designed to cool the beam for the MISTRAL RF mass spectrometer on- line at ISOLDE. The work is carried out partly within the frame of the European Community research network: EXOTRAPS. (9 refs).

  12. Reactive sputtering of titanium in Ar/CH4 gas mixture: Target poisoning and film characteristics

    International Nuclear Information System (INIS)

    Reactive sputtering of titanium target in the presence of Ar/CH4 gas mixture has been investigated. With the addition of methane gas to above 1.5% of the process gas a transition from the metallic sputtering mode to the poison mode was observed as indicated by the change in cathode current. As the methane gas flow concentration increased up to 10%, the target was gradually poisoned. The hysteresis in the cathode current could be plotted by first increasing and then subsequently decreasing the methane concentration. X-ray diffraction and X-ray photoelectron spectroscopy analyses of the deposited films confirmed the formation of carbide phases and the transition of the process from the metallic to compound sputtering mode as the methane concentration in the sputtering gas is increased. The paper discusses a sputtering model that gives a rational explanation of the target poisoning phenomenon and shows an agreement between the experimental observations and calculated results.

  13. Soliton dynamics in gas-filled hollow-core photonic crystal fibers

    CERN Document Server

    Saleh, Mohammed F

    2015-01-01

    Gas-filled hollow-core photonic crystal fibers offer unprecedented opportunities to observe novel nonlinear phenomena. The various properties of gases that can be used to fill these fibers give additional degrees of freedom for investigating nonlinear pulse propagation in a wide range of different media. In this review, we will consider some of the the new nonlinear interactions that have been discovered in recent years, in particular those which are based on soliton dynamics.

  14. Soliton dynamics in gas-filled hollow-core photonic crystal fibers

    International Nuclear Information System (INIS)

    Gas-filled hollow-core photonic crystal fibers offer unprecedented opportunities to observe novel nonlinear phenomena. The various properties of gases that can be used to fill these fibers give additional degrees of freedom for investigating nonlinear pulse propagation in a wide range of different media. In this review, we will consider some of the the new nonlinear interactions that have been discovered in recent years, in particular those which are based on soliton dynamics. (topical review)

  15. AMS Measurement of 36Cl With a Gas-filled Time of Flight Detector

    Institute of Scientific and Technical Information of China (English)

    GUANYong-jing; HEMing; RUANXiang-dong; WANGHui-juan; LIGuo-qiang; WUShao-yong; WUWei-ming; JIANGShan

    2003-01-01

    In order to determine 36Cl and 36S with high sensitivity by AMS, the present study has been done.Difference of time flight in the gas dependences to total energy, gas pressure in the chamber, and the flight length for isobars. The time resolution (FWHM) of the detector system is 800 ps without gas-filled when the ion energy is 72 MeV. Time straggling is growth with the increase of gas pressure in the chamber.Time straggling caused by the gas pressure is shown in Fig.1.

  16. Thomson scattering diagnostics of decay processes of Ar/SF6 gas-blast arcs confined by a nozzle

    International Nuclear Information System (INIS)

    Because of its instability, it is difficult to measure precisely the electron density (ne) of a long-gap decaying arc discharge in a circuit breaker. However, it is well known that it is an essential parameter for the determination of success or failure of the current interruption in a circuit breaker. In this paper, the spatiotemporal evolutions of the electron density were successfully measured in decaying SF6 gas-blast arc discharges formed with a long gap (50 mm) in a confined nozzle using laser Thomson scattering. Pure Ar gas and an 80%Ar/20%SF6 mixture gas were used as the arc quenching media at atmospheric pressure. After reducing the current to zero, both the measured ne and arc radius in the Ar/SF6 gas arc clearly decayed more rapidly than in the pure Ar gas arc. (fast track communication)

  17. Development of Insulation Technology in Compact SF6 Gas-filled Bushings

    Science.gov (United States)

    Rokunohe, Toshiaki; Kato, Tatsuro; Hirose, Makoto; Ishiguro, Tetsu

    As for gas insulated switchgear (GIS), small space requirement and economical efficiency have been demanded. Circuit breakers (CB), disconnecting switches (DS) and earthing switches (ES) have been designed toward compactness. Compact & light bushings have been also required. As for bushings of GIS, there are roughly three types; capacitor, gas-filled and molding bushings. Since gas-filled bushings have the feature which is both of the lightness and the economical efficiency, it is important to develop compact and light gas-filled bushings by improvement of insulation technology. The main subject for compact design is reduction of electric field strength on the outside hollow insulator around the inside grounded electrode tip. We devised a new inner grounded electrode structure which consists of some column electrodes. This paper describes the effect of reduction of maximum value of electric field strength on the outside hollow insulator by a new inner grounded electrode. Then, improvement of insulation performance for electrodes with insulation coating in SF6 gas is described as composite insulation technology. Finally, the efficacy of these insulation technologies is described by fundamental insulation test results of prototype compact 800kV SF6 gas-filled bushing.

  18. Isobaric Identification Using Gas-Filled Time-of-Flight Measurements in an Accelerator Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    GUAN Yong-Jing; RUAN Xiang-Dong; HE Ming; WANG Hui-Juan; LI Guo-Qiang; WU Shao-Yong; DONG Ke-Jun; LIN Min; JIANG Shan

    2005-01-01

    @@ A gas-filled time-of-flight (GF-TOF) detector has been built and developed to improve the ability of isobaric identification in accelerator mass spectrometry (AMS) measurements, and a time resolution (without gas filled)of better than 350ps is achieved. The GF-TOF detector is tested by means of measuring a standard AgCl(36Cl/Cl = 7.6 × 10-9g/g) sample with the 36Cl ion energy of 64, 49 and 33MeV, respectively. 36Cl and 36S particles were successfully separated in the TOF spectra output from the GF-TOF detector. The comparison between the gas-filled time-of-flight method and the △E - E method is described. Some results relative to the GF-TOF method are given as well.

  19. Gas-filled targets for large scale-length plasma interaction experiments on Nova

    International Nuclear Information System (INIS)

    Stimulated Brillouin backscatter from large scale-length gas-filled targets has been measured on the Nova laser. These targets were designed to approximate conditions in indirect drive ignition target designs in underdense plasma electron density (ne∼1021/cm3), temperature (Te>3 keV), and gradient scale lengths (Ln∼2 mm, Lv>6 mm) as well as calculated gain for stimulated Brillouin scattering (SBS). The targets used in these experiments were gas-filled balloons with polyimide walls (gasbags) and gas-filled hohlraums. Detailed characterization using x-ray imaging and x-ray and optical spectroscopy verifies that the calculated plasma conditions are achieved. Time-resolved SBS backscatter from these targets is <3% for conditions similar to ignition target designs

  20. Gas-filled targets for large scalelength plasma interaction experiments on Nova

    International Nuclear Information System (INIS)

    Stimulated Brillouin backscatter from large scale length gas-filled targets has been measured on Nova. These targets were designed to approximate conditions in indirect drive ignition target designs in underdense plasma electron density (ne∼1021/cm3), temperature (Te>3 keV), and gradient scale lengths (Ln∼ mm, Lv>6 mm) as well as calculated gain for stimulated Brillouin scattering (SBS). The targets used in these experiments were gas-filled balloons with polyimide walls (gasbags) and gas-filled hohlraums. Detailed characterization using x-ray imaging and x-ray and optical spectroscopy verifies that the calculated plasma conditions are achieved. Time-resolved SBS backscatter from these targets is <3% for conditions similar to ignition target designs

  1. Synchrotron radiation-excited etching of ZnTe using Ar gas

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Tooru [Synchrotron Light Application Center, Saga University, 1 Honjyo, Saga 840-8502 (Japan)]. E-mail: ttanaka@cc.saga-u.ac.jp; Kume, Yusuke [Synchrotron Light Application Center, Saga University, 1 Honjyo, Saga 840-8502 (Japan); Hayashida, Kazuki [Venture Business Laboratory, Saga University, 1 Honjyo, Saga 840-8502 (Japan); Saito, Katsuhiko [Venture Business Laboratory, Saga University, 1 Honjyo, Saga 840-8502 (Japan); Nishio, Mitsuhiro [Department of Electrical and Electronic Engineering, Saga University, 1 Honjyo, Saga 840-8502 (Japan); Guo, Qixin [Department of Electrical and Electronic Engineering, Saga University, 1 Honjyo, Saga 840-8502 (Japan); Ogawa, Hiroshi [Synchrotron Light Application Center, Saga University, 1 Honjyo, Saga 840-8502 (Japan)

    2005-08-15

    Dependence of the synchrotron light-excited etching of ZnTe on the pressure has been investigated. Ar gas was used as an etching gas, and the ZnTe sample was negatively biased against the reaction chamber. The etching rate increases with increasing the pressure, and the maximum etching rate of 16.7 nm/A min has been achieved. In order to discuss the etching mechanism, the wavelength dependence of the etching properties was examined using a LiF window.

  2. New gas-filled mode of the large-acceptance spectrometer VAMOS

    International Nuclear Information System (INIS)

    A new gas-filled operation mode of the large-acceptance spectrometer VAMOS at GANIL is reported. A beam rejection factor greater than 1010 is obtained for the 40Ca+150Sm system at 196 MeV. The unprecedented transmission efficiency for the evaporation residues produced in this reaction is estimated to be around 80% for αx n channels and above 95% for x ny p channels. A detailed study of the performance of the gas-filled VAMOS and future developments are discussed. This new operation mode opens avenues to explore the potential of fusion reactions in various kinematics.

  3. New gas-filled mode of the large-acceptance spectrometer VAMOS

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, C., E-mail: schmitt@ganil.f [GANIL, CEA/DSM-CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France); Rejmund, M.; Navin, A.; Lecornu, B.; Jacquot, B.; France, G. de; Lemasson, A.; Shrivastava, A. [GANIL, CEA/DSM-CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France); Greenlees, P.; Uusitalo, J. [Department of Physics, University of Jyvaskyla, P.O. Box 35, FI-40014, Jyvaskyla (Finland); Subotic, K. [VINCA Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia); Gaudefroy, L. [CEA, DAM, DIF, F-91297 Arpajon (France); Theisen, Ch.; Sulignano, B. [CEA-Saclay DSM/IRFU/SPhN, F-91191 Gif/Yvette Cedex (France); Dorvaux, O.; Stuttge, L. [IPHC, UMR7178, IN2P3-CNRS et Universite Louis Pasteur, BP28, F-67037 Strasbourg (France)

    2010-09-21

    A new gas-filled operation mode of the large-acceptance spectrometer VAMOS at GANIL is reported. A beam rejection factor greater than 10{sup 10} is obtained for the {sup 40}Ca+{sup 150}Sm system at 196 MeV. The unprecedented transmission efficiency for the evaporation residues produced in this reaction is estimated to be around 80% for {alpha}x n channels and above 95% for x ny p channels. A detailed study of the performance of the gas-filled VAMOS and future developments are discussed. This new operation mode opens avenues to explore the potential of fusion reactions in various kinematics.

  4. Gas gain limitation in low pressure proportional counters filled with TEG mixtures

    International Nuclear Information System (INIS)

    Proportional counters filled with tissue equivalent gas mixtures (TEPC) can be used to simulate interactions and energy transferred to small tissue volumes. One criteria which allows to use TEPC as the dose meter is that the particle ranges are larger compared to the gas volume. TEPC achieve this by operating at low gas pressures. Single ionization events dominate the distribution of low-LET radiation at low gas pressure and therefore their detection is of primary importance, a high gas gain is necessary. Therefore gas gain factor has been measured for Methane- and Propane-based tissue equivalent gas mixtures. The highest stable gas gains, second ionization Townsend coefficient and electron avalanche dimensions have been determined

  5. Gas gain limitation in low pressure proportional counters filled with TEG mixtures

    Science.gov (United States)

    Kowalski, T. Z.

    2014-12-01

    Proportional counters filled with tissue equivalent gas mixtures (TEPC) can be used to simulate interactions and energy transferred to small tissue volumes. One criteria which allows to use TEPC as the dose meter is that the particle ranges are larger compared to the gas volume. TEPC achieve this by operating at low gas pressures. Single ionization events dominate the distribution of low-LET radiation at low gas pressure and therefore their detection is of primary importance, a high gas gain is necessary. Therefore gas gain factor has been measured for Methane- and Propane-based tissue equivalent gas mixtures. The highest stable gas gains, second ionization Townsend coefficient and electron avalanche dimensions have been determined.

  6. Silicon etch using SF6/C4F8/Ar gas mixtures

    International Nuclear Information System (INIS)

    While plasmas using mixtures of SF6, C4F8, and Ar are widely used in deep silicon etching, very few studies have linked the discharge parameters to etching results. The authors form such linkages in this report. The authors measured the optical emission intensities of lines from Ar, F, S, SFx, CF2, C2, C3, and CS as a function of the percentage C4F8 in the gas flow, the total gas flow rate, and the bias power. In addition, the ion current density and electron temperature were measured using a floating Langmuir probe. For comparison, trenches were etched of various widths and the trench profiles (etch depth, undercut) were measured. The addition of C4F8 to an SF6/Ar plasma acts to reduce the availability of F as well as increase the deposition of passivation film. Sulfur combines with carbon in the plasma efficiently to create a large optical emission of CS and suppress optical emissions from C2 and C3. At low fractional flows of C4F8, the etch process appears to be controlled by the ion flux more so than by the F density. At large C4F8 fractional flows, the etch process appears to be controlled more by the F density than by the ion flux or deposition rate of passivation film. CF2 and C2 do not appear to cause deposition from the plasma, but CS and other carbon containing molecules as well as ions do

  7. Towards Complete and Realistic Studies for Rare-Gas Ionic Clusters, the Ar^+_3 Example

    Science.gov (United States)

    Gadea, Florent Xavier; Amarouche, Mohand

    1995-12-01

    The approach we have developped for the ab initio simulation of rare-gas ionic clusters is reviewed and applied to Ar^+_3. It is based on a DIM (Diatomic In Molecules) modelling for the electronic Hamiltonian and transition dipole moments, on approximate estimations for the absorption spectrum and a HWD (Hemiquantal dynamics with the Whole DIM basis) treatment of the fragmentation dynamics. The theoretical study is devoted to three basic aspects: the structure of the ions, their absorption spectrum and their fragmentation dynamics. These aspects correspond respectively to equilibrium, short time and long time dynamics. The results for Ar^+_3 are reviewed (structure, visible spectrum, photofragmentation dynamics, kinetic energy distribution of photofragments) and in addition new ones for the UV absorption spectrum are presented and discussed.

  8. Measurement of void volume of a fuel rod and the exchange of occluded gases from mixed carbide fuel with filling gas helium

    Energy Technology Data Exchange (ETDEWEB)

    Rama Rao, G.A. [Bhabha Atomic Res. Centre, Bombay (India). Fuel Chem. Div.; Kulkarni, S.G. [Bhabha Atomic Res. Centre, Bombay (India). Fuel Chem. Div.; Venugopal, V. [Bhabha Atomic Res. Centre, Bombay (India). Fuel Chem. Div.; Manchanda, V.K. [Radiochemistry Division, Bhabha Atomic Research Centre, Bombay 400 085 (India); Goswami, G.L. [Atomic Fuels Division, Bhabha Atomic Research Centre, Bombay 400 085 (India)

    1995-02-01

    The presence of gaseous impurities in the filling gas of a fuel pin is detrimental to the thermal performance of a nuclear reactor fuel. The composition of the filling gas does not remain constant throughout the life of the fuel pin. The gas exchange phenomena that occur between the cover gas and impurity gases affect the fuel performance more severely in (U, Pu)O{sub 2} fuel pin due to its inherently poor thermal conductivity than in advanced fuels such as mixed carbides and nitrides. In the present study the exchange phenomenon of the occluded gases present in our Fast Breeder Test Reactor (FBTR) fuel pellets [(U{sub 0.30}, Pu{sub 0.70})C with 6500 ppm O] with the cover gas helium was observed as a function of time and temperature. Quantitative analysis of the released gases namely H{sub 2}, O{sub 2}+Ar, N{sub 2}, CH{sub 4} and CO was carried out at subambient pressure by gas chromatography. The void volume of the fuel element is determined experimentally by gas equilibration with known volume. ((orig.))

  9. Measurement of void volume of a fuel rod and the exchange of occluded gases from mixed carbide fuel with filling gas helium

    Science.gov (United States)

    Rao, G. A. Rama; Kukarni, S. G.; Venugoopal, V.; Manchanda, V. K.; Goswami, G. L.

    1995-02-01

    The presence of gaseous impurities in the filling gas of a fuel pin is detriental to the thermal performance of a nuclear reactor fuel. The composition of the filling gas does not remain constant throughout the life of the fuel pin. The gas exchange phenomena that occur between the cover gas and impurity gases affect the fuel performance more severely in (U, Pu)O 2 fuel pin due to its inherently poor thermal conductivity than in advanced fuels such as mixed carbides and nitrides. In the present study the exchange phenomenon of the occluded gases present in our Fast Breeder Test Reactor (FBTR) fuel pellets [(U 0.30, Pu 0.70)C with 6500 ppm o] with the cover gas helium was observed as a function of time and temperature. Quantitative analysis of the released gases namely H 2, O 2 + Ar, N 2, CH 4 and CO was carried out at subambient pressure by gas chromatography. The void volume of the fuel element is determined experimentally by gas equilibration with known volume.

  10. Calibration of cosmogenic noble gas production in ordinary chondrites based on 36Cl-36Ar ages. Part 1: Refined produced rates for cosmogenic 21Ne and 38Ar

    Science.gov (United States)

    Dalcher, N.; Caffee, M. W.; Nishiizumi, K.; Welten, K. C.; Vogel, N.; Wieler, R.; Leya, I.

    2013-10-01

    We measured the concentrations and isotopic compositions of He, Ne, and Ar in bulk samples and metal separates of 14 ordinary chondrite falls with long exposure ages and high metamorphic grades. In addition, we measured concentrations of the cosmogenic radionuclides 10Be, 26Al, and 36Cl in metal separates and in the nonmagnetic fractions of the selected meteorites. Using cosmogenic 36Cl and 36Ar measured in the metal separates, we determined 36Cl-36Ar cosmic-ray exposure (CRE) ages, which are shielding-independent and therefore particularly reliable. Using the cosmogenic noble gases and radionuclides, we are able to decipher the CRE history for the studied objects. Based on the correlation 3He/21Ne versus 22Ne/21Ne, we demonstrate that, among the meteorites studied, only one suffered significant diffusive losses (about 35%). The data confirm that the linear correlation 3He/21Ne versus 22Ne/21Ne breaks down at high shielding. Using 36Cl-36Ar exposure ages and measured noble gas concentrations, we determine 21Ne and 38Ar production rates as a function of 22Ne/21Ne. The new data agree with recent model calculations for the relationship between 21Ne and 38Ar production rates and the 22Ne/21Ne ratio, which does not always provide unique shielding information. Based on the model calculations, we determine a new correlation line for 21Ne and 38Ar production rates as a function of the shielding indicator 22Ne/21Ne for H, L, and LL chondrites with preatmospheric radii less than about 65 cm. We also calculated the 10Be/21Ne and 26Al/21Ne production rate ratios for the investigated samples, which show good agreement with recent model calculations.

  11. Optical emission investigation of laser-produced MgB2 plume expanding in an Ar buffer gas

    OpenAIRE

    Amoruso, S.; Bruzzese, R.; N. Spinelli; Velotta, R.; Wang, X.; Ferdeghini, C.

    2002-01-01

    Optical emission spectroscopy is used to study the dynamics of the plasma generated by pulsed-laser irradiation of a MgB2 target, both in vacuum and at different Ar buffer gas pressures. The analysis of the time-resolved emission of selected species shows that the Ar background gas strongly influences the plasma dynamics. Above a fixed pressure, plasma propagation into Ar leads to the formation of blast waves causing both a considerable increase of the fraction of excited Mg atoms and a simul...

  12. Modeling of drive-symmetry experiments in gas-filled hohlraums at Nova

    International Nuclear Information System (INIS)

    Experiments on capsule implosions in gas-filled hohlraums have been carried out on the NOVA Laser at Lawrence Livermore National Laboratory. Observed capsule shapes are more oblate than predicted using modeling methods which agree well with experiments in evacuated hohlraums. Improvements in modeling required to calculate these experiments and additional experiments are being pursued

  13. Automation of the experiments at the Dubna gas-filled recoil separator

    International Nuclear Information System (INIS)

    Schematics, codes and Builder C++ applications aimed at the synthesis of superheavy elements at the Dubna gas-filled recoil separator (DGFRS) of FLNR (JINR) are presented. Examples of applications in the heavy-ion-induced nuclear reactions with 48Ca projectiles are presented.

  14. Research on heavy elements using the JYFL gas-filled recoil separator RITU

    International Nuclear Information System (INIS)

    A gas-filled recoil separator for studies of heavy elements produced in heavy-ion-induced fission reaction has been constructed. New neutron-deficient isotopes with Z=85-90 have been identified through their alpha decay. (author). 40 refs, 3 figs, 2 tabs

  15. Visual application for beam associated systems of gas-filled separator

    International Nuclear Information System (INIS)

    PC based code for Windows 98 operating together with the beam associated systems of the Dubna Gas-filled Recoil Separator is described. It is coded in C++ (Borland Builder v. 3.0). This code was tested in heavy ion-induced nuclear reactions at U-400 main Flerov Laboratory of Nuclear Reactions (FLNR) cyclotron

  16. Physiological and behavioral responses of poultry exposed to gas-filled high expansion foam

    NARCIS (Netherlands)

    Mckeegan, D.E.F.; Reimert, H.G.M.; Hindle, V.A.; Boulcott, P.; Sparrey, J.M.; Wathes, C.M.; Demmers, T.G.M.; Gerritzen, M.A.

    2013-01-01

    Disease control measures require poultry to be killed on farms to minimize the risk of disease being transmitted to other poultry and, in some cases, to protect public health. We assessed the welfare implications for poultry of the use of high-expansion gas-filled foam as a potentially humane, emerg

  17. Effects of plasma physics on capsule implosions in gas-filled hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Lindman, E.L.; Delamater, N.D.; Magelssen, G.R.; Hauer, A.

    1994-10-01

    Initial experiments on capsule implosions in gas-filled hohlraums have been carried out on the NOVA Laser at Lawrence Livermore National Laboratory. Observed capsule shapes from preliminary experiments are more oblate than predicted. Improvements in modeling required to calculate these experiments and additional experiments are being pursued.

  18. Production of high intensity heavy ion beams for the experiments on a gas-filled separator

    International Nuclear Information System (INIS)

    A gas-filled separator of heavy ions induced reactions products permits a substantial suppression of the background from primary beam ions. This feature allows one to obtain an extremely intensive ion beam from the cyclotron U-400. Experimental studies were performed to investigate the operation of various stripping carbon foils. 7 refs.; 2 figs

  19. Deposition dynamics of droplet-free Si nanoparticles in Ar gas using laser ablation

    Science.gov (United States)

    Takeuchi, D.; Mizuta, T.; Makimura, T.; Yoshida, S.; Fujita, M.; Hata, K.; Shigekawa, H.; Murakami, K.

    2002-09-01

    Droplet-free deposition of Si nanoparticle films has been studied applying time-resolved imaging of Si nanoparticles formed by laser ablation of Si targets in Ar gas. We found that Si nanoparticles can be deposited not only on substrates facing to the targets but also on substrates placed beside the target. We further confirmed using a scanning tunneling microscope (STM), Si nanoparticles with sizes of 5-8 nm are deposited on substrates placed beside the target and using a scanning electron microscope (SEM) on the substrates, no droplets are observed.

  20. The gas-filled magnet: An isobar separator for accelerator mass spectrometry

    International Nuclear Information System (INIS)

    The most difficult problem for accelerator mass spectrometry is the rejection of stable atomic isobars. The intensity of isobaric interference is expected to become a problem for 36Cl measurements with the use of new high-intensity ion sources. Although better chemical separation may be possible through improved sample preparation, the device expected to help most with this problem is the gas-filled magnet. We tested a gas-filled Enge split-pole spectrograph combined with a multi-plate gas ionization detector for the separation of 36S from 36Cl and obtained an isobar separation of about two orders of magnitude better than that possible with the detector alone. 10 refs., 3 figs., 1 tab

  1. Utilizing Gas Filled Cavities for the Generation of an Intense Muon Source

    Energy Technology Data Exchange (ETDEWEB)

    Stratakis, Diktys; Neuffer, David V.

    2015-05-01

    A key requirement for designing intense muon sources is operating rf cavities in multi-tesla magnetic fields. Recently, a proof-of-principle experiment demonstrated that an rf cavity filed with high pressure hydrogen gas could meet this goal. In this study, rigorous simulation is used to design and evaluate the performance of an intense muon source with gas filled cavities. We present a new lattice design and compare our results with conventional schemes. We detail the influence of gas pressure on the muon production rate.

  2. D2 gas-filled blisters on deuterium-bombarded tungsten

    International Nuclear Information System (INIS)

    Most of spherical blisters formed by deuterium (D) bombardment (38 eV/D) up to 3 x 1024 D/m2 at 300 K on polycrystalline tungsten are fully elastic deformations. This has been proven by opening individual blisters with a focused ion beam and in situ observation of their complete relaxation by scanning electron microscopy. The D2 gas filling is confirmed by observing simultaneously the D2 puff. The gas pressure is causal for the stability of such spherical blisters after implantation and the gas release leads to sudden relaxation. The dilatation of the blister cap by trapped D can be excluded as cause for the blisters.

  3. Utilizing gas-filled cavities for the generation of an intense muon source

    International Nuclear Information System (INIS)

    A key requirement for designing intense muon sources is operating rf cavities in multi-tesla magnetic fields. Recently, a proof-of-principle experiment demonstrated that an rf cavity filed with high pressure hydrogen gas could meet this goal. In this study, rigorous simulation is used to design and evaluate the performance of an intense muon source with gas filled cavities. We present a new lattice design and compare our results with conventional schemes. We detail the influence of gas pressure on the muon production rate.

  4. Utilizing gas-filled cavities for the generation of an intense muon source

    Energy Technology Data Exchange (ETDEWEB)

    Stratakis, Diktys [Brookhaven National Lab. (BNL), Upton, NY (United States); Neuffer, David V. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-05-03

    A key requirement for designing intense muon sources is operating rf cavities in multi-tesla magnetic fields. Recently, a proof-of-principle experiment demonstrated that an rf cavity filed with high pressure hydrogen gas could meet this goal. In this study, rigorous simulation is used to design and evaluate the performance of an intense muon source with gas filled cavities. We present a new lattice design and compare our results with conventional schemes. We detail the influence of gas pressure on the muon production rate.

  5. Ubiquitous argonium (ArH$^+$) in the diffuse interstellar medium -- a molecular tracer of almost purely atomic gas

    CERN Document Server

    Schilke, Peter; Mueller, Holger S P; Comito, Claudia; Bergin, Edwin A; Lis, Dariusz C; Gerin, Maryvonne; Black, John H; Wolfit, Mark; Indriolo, Nick; Pearson, John C; Menten, Karl M; Winkel, Benjamin; Sanchez-Monge, Alvaro; Moeller, Thomas; Godard, Benjamin; Falgarone, Edith

    2014-01-01

    We describe the assignment of a previously unidentified interstellar absorption line to ArH$^+$ and discuss its relevance in the context of hydride absorption in diffuse gas with a low H$_2$ fraction. The column densities along several lines of sight are determined and discussd in the framework of chemical models. The column densities of ArH$^+$ are compared to those of other species, tracing interstellar medium (ISM) components with different H$_2$ abundances. Chemical models are constructed, taking UV radiation and cosmic ray ionization into account. Due to the detection of two isotopologues, $^{36}$ArH$^+$ and $^{38}$ArH$^+$, we are confident about the carrier assignment to ArH$^+$. NeH$^+$ is not detected with a limit of [NeH$^+$]/[ArH$^+$] $\\le$ 0.1. The derived column densities agree well with the predictions of chemical models. ArH$^+$ is a unique tracer of gas with a fractional H$_2$ abundance of $10^{-4}- 10^{-3}$ and shows little correlation with H$_2$O$^+$, which traces gas with a fractional H$_2$ ...

  6. The Influence of Electrode Material on Gas-Filled Surge Arresters Response Time in gamma and X radiation field

    International Nuclear Information System (INIS)

    The aim of this paper is to investigate the influence of electrode material on the gas filled surge arrester' model pulse shape characteristic in gamma and X radiation field. We found that both radiations have increased gas filled surge arresters response time. The obtained results show that the optimal solution for GFSA model is with Al electrodes. (author)

  7. High pressure laser plasma studies. [energy pathways in He-Ar gas mixtures at low pressure

    Science.gov (United States)

    Wells, W. E.

    1980-01-01

    The operation of a nuclear pumped laser, operating at a wavelength of 1.79 micron m on the 3d(1/2-4p(3/2) transition in argon with helium-3 as the majority gas is discussed. The energy pathways in He-Ar gas were investigated by observing the effects of varying partial pressures on the emissions of levels lying above the 4p level in argon during a pulsed afterglow. An attempt is made to determine the population mechanisms of the 3d level in pure argon by observing emission from the same transition in a high pressure plasma excited by a high energy electron beam. Both collisional radiative and dissociative recombination are discussed.

  8. A comparative study of naturally ventilated and gas filled windows for hot climates

    International Nuclear Information System (INIS)

    The use of absorbing gases filling the gap between glass sheets appears to be an alternative solution for thermally insulated glass windows. Fluid flow in the gap between the glass sheets either forced or natural offers other options for thermally efficient windows. In this work, the thermal efficiencies of glass windows filled with an absorbing gas exposed to solar radiation in hot climate is compared with both a simple glass window and a double glass window naturally ventilated. The two-dimensional transient energy equations with radiation absorption in the internal domain are used to model the simple glass window. The cumulative wavenumber model (CW) for real gas modeling together the discrete ordinates method is used to model double glass window filled with infrared absorbing gases. The numerical simulations were realized with three mixtures of gases, a strongly absorbing gas mixture, an intermediate absorbing gas mixture and a transparent to infrared radiation mixture. To model a double glass window naturally ventilated, a two-dimensional transient laminar incompressible flow formulation is used and the buoyancy effects are accounting for by the Bussinesq approximation. Heat transfer through the windows is calculated and the total heat gain coefficient is compared for the three types of windows.

  9. Etching characteristic and mechanism of BST thin films using inductively coupled Cl2/Ar plasma with additive CF4 gas

    International Nuclear Information System (INIS)

    BST thin films were etched with inductively coupled CF4/(Cl2+Ar) plasmas. The maximum etch rate of the BST thin films was 53.6 nm/min for a 10% CF4 to the Cl2/Ar gas mixture at RF power of 700 W, DC bias of -150 V, and chamber pressure of 2 Pa. Small addition of CF4 to the Cl2/Ar mixture increased chemical effect. Consequently, the increased chemical effect caused the increase in the etch rate of the BST thin films. To clarify the etching mechanism, the surface reaction of the BST thin films was investigated by X-ray photoelectron spectroscopy

  10. Effects of sputtering Ar gas pressure in the exchange stiffness constant of Co40Fe40B20 thin films

    International Nuclear Information System (INIS)

    The exchange stiffness constants of 25-nm-thick Co40Fe40B20 films are investigated by Brillouin light scattering. Series of Co40Fe40B20 films is prepared with various Ar gas pressures, and we found that the exchange stiffness constant decreases from 1.41 to 0.98×10−11 1rom 1.41 to 0.98ous Ar gas pressures, and we found that thin stiffness constants are much smaller than CoFe values due to the B atoms, and the dependence of Ar gas pressure is noticeable. Based on our previous theoretical work, the switching current density of spin transfer torque magnetic random access memory is very sensitive on the exchange stiffness constant; it implies that engineering the exchange stiffness constant by the fabrication process is important to reduce switching current density and the dispersion of switching current density. - Highlights: ► We study the exchange stiffness constant in CoFeB thin films. ► Series of CoFeB films is prepared with various Ar gas pressures. ► We found the exchange stiffness constant decreases with increasing Ar gas pressure

  11. Separation of actinide-made transurania by a gas-filled magnetic separator

    International Nuclear Information System (INIS)

    The performance of the gas-filled magnetic separator HECK at the UNI-LAC at GSI Darmstadt is described. The system consists of a 30 -dipole magnet and a quadrupole doublet of wide aperture. The separator is operated with helium at pressures between (0.1-1) hPa. It is used to investigate heavy ion induced fusion products in-flight. The recoils emerging from a thin target are separated with high efficiency of (10-50)%. The suppression factor of primary beam particles and transfer products is (1015) and (103), respectively. In this application of a gas-filled separator to synthesize transuranium elements using 238U-targets, isotopes of the elements fermium and nobelium were identified in irradiations with 16O- and 20Ne-beams. (orig.)

  12. High-density carbon ablator ignition path with low-density gas-filled rugby hohlraum

    Energy Technology Data Exchange (ETDEWEB)

    Amendt, Peter; Ho, Darwin D.; Jones, Ogden S. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

    2015-04-15

    A recent low gas-fill density (0.6 mg/cc {sup 4}He) cylindrical hohlraum experiment on the National Ignition Facility has shown high laser-coupling efficiency (>96%), reduced phenomenological laser drive corrections, and improved high-density carbon capsule implosion symmetry [Jones et al., Bull. Am. Phys. Soc. 59(15), 66 (2014)]. In this Letter, an ignition design using a large rugby-shaped hohlraum [Amendt et al., Phys. Plasmas 21, 112703 (2014)] for high energetics efficiency and symmetry control with the same low gas-fill density (0.6 mg/cc {sup 4}He) is developed as a potentially robust platform for demonstrating thermonuclear burn. The companion high-density carbon capsule for this hohlraum design is driven by an adiabat-shaped [Betti et al., Phys. Plasmas 9, 2277 (2002)] 4-shock drive profile for robust high gain (>10) 1-D ignition performance and large margin to 2-D perturbation growth.

  13. X-ray Sources Generated from Gas-Filled Laser-Heated Targets

    Energy Technology Data Exchange (ETDEWEB)

    Back, C A; Grun, J; Decker, C D; Davis, J; Laming, J M; Feldman, U; Suter, L J; Landen, O L; Miller, M; Serduke, F; Wuest, C

    2000-06-06

    The X-ray sources in the 4-7 keV energy regime can be produced by laser-irradiating high-Z gas-filled targets with high-powered lasers. A series of experiments have been performed using underdense targets that are supersonically heated with {approx} 35 W of 0.35 {micro}m laser light. These targets were cylindrical Be enclosures that were filled with 1-2 atms of Xe gas. L-shell x-ray emission is emitted from the plasma and detected by Bragg crystal spectrometers and x-ray diodes. Absolute flux measurements show conversion efficiencies of {approx} 10% in the multi-kilovolt x-ray emission. These sources can be used as bright x-ray backlighters or for material testing.

  14. Demonstrated high performance of gas-filled rugby-shaped hohlraums on Omega

    Energy Technology Data Exchange (ETDEWEB)

    Philippe, F. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Tassin, V. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Depierreux, S. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Gauthier, P. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Masson-Laborde, P. E. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Monteil, M. C. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Seytor, P. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Villette, B. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Lasinski, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Park, H. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ross, J. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Amendt, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Doeppner, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hinkel, D. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wallace, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Williams, E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Michel, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Frenje, J. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Gatu-Johnson, M. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Li, C. K. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Petrasso, R. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Glebov, V. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics; Sorce, C. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics; Stoeckl, C. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics; Nikroo, A. [General Atomics, San Diego, CA (United States); Giraldez, E. [General Atomics, San Diego, CA (United States)

    2014-07-25

    A direct experimental comparison of rugby-shaped and cylindrical shaped gas-filled hohlraums on the Omega laser facility demonstrates that higher coupling and minimal backscatter can be achieved in the rugby geometry, leading to significantly enhanced implosion performance. A nearly 50% increase of x-ray drive is associated with earlier bangtime and increase of neutron production. The observed drive enhancement from rugby geometry in this study is almost twice stronger than in previously published results.

  15. Demonstrated high performance of gas-filled rugby-shaped hohlraums on Omega

    Energy Technology Data Exchange (ETDEWEB)

    Philippe, F.; Villette, B. [CEA, DAM, DIF, F-91297 Arpajon (France); Michel, P. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Petrasso, R. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Stoeckl, C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Giraldez, E. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Tassin, V.; Depierreux, S.; Gauthier, P.; Masson-Laborde, P. E.; Monteil, M. C.; Seytor, P.; Lasinski, B.; Park, H. S.; Ross, J. S.; Amendt, P.; Döppner, T.; Hinkel, D. E.; Wallace, R.; Williams, E.; and others

    2014-07-15

    A direct experimental comparison of rugby-shaped and cylindrical shaped gas-filled hohlraums on the Omega laser facility demonstrates that higher coupling and minimal backscatter can be achieved in the rugby geometry, leading to significantly enhanced implosion performance. A nearly 50% increase of x-ray drive is associated with earlier bangtime and increase of neutron production. The observed drive enhancement from rugby geometry in this study is almost twice stronger than in previously published results.

  16. Tunable frequency-up/down conversion in gas-filled hollow-core photonic crystal fibers

    OpenAIRE

    Saleh, Mohammed F.; Biancalana, Fabio

    2015-01-01

    Based on the interplay between photoionization and Raman effect in gas-filled photonic crystal fibers, we propose a new optical device to control frequency-conversion of ultrashort pulses. By tuning the input-pulse energy, the output spectrum can be either down-converted, up-converted, or even frequency-shift compensated. For low input energies, Raman effect is dominant and leads to a redshift that increases linearly during propagation. For larger pulse energies, photoionization starts to tak...

  17. Welfare assessment of gas-filled foam as an agent for killing poultry

    OpenAIRE

    Gerritzen, M.A.; Reimert, H.G.M.; Hindle, V.A.; McKeegan, D.E.F.; Sparrey, J.

    2010-01-01

    During outbreaks of notifiable diseases in poultry measures are taken to restrict the spread of the disease. Mass on-farm killing of birds using gasfilled foam is such a measure. This study examines the method and technologies involved using gas-filled foam and looks at the problems involved by scaling up the procedure. Methods and results are discussed in relation to poultry physiology and behaviour monitored during controlled studies. Recommendations are made for system design and an operat...

  18. Developments for transactinide chemistry experiments behind the gas-filled separator TASCA

    OpenAIRE

    Even, Julia

    2011-01-01

    Topic of this thesis is the development of experiments behind the gas-filled separator TASCA(TransActinide Separator and Chemistry Apparatus) to study the chemical properties of the transactinide elements.rnIn the first part of the thesis, the electrodepositions of short-lived isotopes of ruthenium and osmium on gold electrodes were studied as model experiments for hassium. From literature it is known that the deposition potential of single atoms differs significantly from the potential predi...

  19. High-energy laser-pulse self-compression in short gas-filled fibers

    OpenAIRE

    Anderson, P N; Horak, P.; Frey, J G; Brocklesby, W.S.

    2014-01-01

    We examine the spatiotemporal compression of energetic femtosecond laser pulses within short gas-filled fibers. The study is undertaken using an advanced nonlinear pulse propagation model based on a multimode generalized nonlinear Schrödinger equation that has been modified to include plasma effects. Plasma defocusing and linear propagation effects are shown to be the dominant processes within a highly dynamical mechanism that enables 100-fs pulses to be compressed into the few-cycle regime a...

  20. Differentiated muscles are mandatory for gas-filling of the Drosophila airway system

    Directory of Open Access Journals (Sweden)

    Yiwen Wang

    2015-12-01

    Full Text Available At the end of development, organs acquire functionality, thereby ensuring autonomy of an organism when it separates from its mother or a protective egg. In insects, respiratory competence starts when the tracheal system fills with gas just before hatching of the juvenile animal. Cellular and molecular mechanisms of this process are not fully understood. Analyses of the phenotype of Drosophila embryos with malformed muscles revealed that they fail to gas-fill their tracheal system. Indeed, we show that major regulators of muscle formation like Lame duck and Blown fuse are important, while factors involved in the development of subsets of muscles including cardiac and visceral muscles are dispensable for this process, suggesting that somatic muscles (or parts of them are essential to enable tracheal terminal differentiation. Based on our phenotypic data, we assume that somatic muscle defect severity correlates with the penetrance of the gas-filling phenotype. This argues that a limiting molecular or mechanical muscle-borne signal tunes tracheal differentiation. We think that in analogy to the function of smooth muscles in vertebrate lungs, a balance of physical forces between muscles and the elasticity of tracheal walls may be decisive for tracheal terminal differentiation in Drosophila.

  1. Numerical Simulation of Debris Cloud Propagation inside Gas-Filled Pressure Vessels under Hypervelocity Impact

    Science.gov (United States)

    Gai, F. F.; Pang, B. J.; Guan, G. S.

    2009-03-01

    In the paper SPH methods in AUTODYN-2D is used to investigate the characteristics of debris clouds propagation inside the gas-filled pressure vessels for hypervelocity impact on the pressure vessels. The effect of equation of state on debris cloud has been investigated. The numerical simulation performed to analyze the effect of the gas pressure and the impact condition on the propagation of the debris clouds. The result shows that the increase of gas pressure can reduce the damage of the debris clouds' impact on the back wall of vessels when the pressure value is in a certain range. The smaller projectile lead the axial velocity of the debris cloud to stronger deceleration and the debris cloud deceleration is increasing with increased impact velocity. The time of venting begins to occur is related to the "vacuum column" at the direction of impact-axial. The paper studied the effect of impact velocities on gas shock wave.

  2. Gas gain limitation in low pressure proportional counters filled with TEG mixtures—part II

    Science.gov (United States)

    Kowalski, T. Z.

    2016-01-01

    Proportional counters filled with tissue equivalent gas mixtures are extremely useful instruments and are being used extensively as sensitive detectors for all types of radiations to measure the energy transferred to small tissue volumes. The linearity of their response is of primary importance. So the investigation and clarification of the physical phenomena taking place in the counter and of the limits within which useful results may be obtained would contribute to a more efficient use and a wider application of these counters. The measured gas gain curves have been fitted to the Diethorn and Williams & Sara gas gain models. The models parameters and their dependence on gas pressure have been determined. It was shown that reduced ionization coefficient α/p is not univocal function of the reduced electric field strength EFS/p.

  3. Efficient Spectral Broadening in the 100-W Average Power Regime Using Gas Filled Kagome HC-PCF and Pulse Compression

    CERN Document Server

    Emaury, Florian; Debord, Benoit; Ghosh, Debashri; Diebold, Andreas; Gerome, Frederic; Suedmeyer, Thomas; Benabid, Fetah; Keller, Ursula

    2014-01-01

    We present nonlinear pulse compression of a high-power SESAM-modelocked thin-disk laser (TDL) using an Ar-filled hypocycloid-core Kagome Hollow-Core Photonic Crystal Fiber (HC-PCF). The output of the modelocked Yb:YAG TDL with 127 W average power, a pulse repetition rate of 7 MHz, and a pulse duration of 740 fs was spectrally broadened 16-fold while propagating in a Kagome HC-PCF containing 13 bar of static Argon gas. Subsequent compression tests performed using 8.4% of the full available power resulted in a pulse duration as short as 88 fs using the spectrally broadened output from the fiber. Compressing the full transmitted power through the fiber (118 W) could lead to a compressed output of >100 W of average power and >100 MW of peak power with an average power compression efficiency of 88%. This simple laser system with only one ultrafast laser oscillator and a simple single-pass fiber pulse compressor, generating both high peak power >100 MW and sub-100-fs pulses at megahertz repetition rate, is very int...

  4. Absolute gas refractometer without gas-filling and pumping process benefiting from quasi-synthetic wavelength theory

    CERN Document Server

    Zhang, Jitao; Li, Yan; Wei, Haoyun

    2012-01-01

    We present a method to measure the refractive index of gas at 633 nm absolutely, which does not need filling or pumping gas during the measurement. We develop a quasi-synthetic wavelength (QSW) theory by means of the configuration of two-frequency Jamin interferometry and vacuum tubes with specific lengths. With the aid of the QSW theory, we construct a gas refractometer and demonstrate its performance by the measurement of dry air and nitrogen gas at different pressures ranging from 80 kPa to 100 kPa. The results indicate that the refractometer has an uncertainty of better than 1E-7 and a dynamic range of 3.95E-4.

  5. The evolution of a spatially homogeneous and isotropic universe filled with a collisionless gas

    International Nuclear Information System (INIS)

    We review the evolution of a spatially homogeneous and isotropic universe described by a Friedmann-Robertson-Walker spacetime filled with a collisionless, neutral, simple, massive gas. The gas is described by a one-particle distribution function which satisfies the Liouville equation and is assumed to be homogeneous and isotropic. Making use of the isometries of the spacetime, we define precisely the homogeneity and isotropicity property of the distribution function, and based on this definition we give a concise derivation of the most general family of such distribution functions. For this family, we construct the particle current density and the stress-energy tensor and consider the coupled Einstein-Liouville system of equations. We find that as long as the distribution function is collisionless, homogenous and isotropic, the evolution of a Friedmann-Robertson-Walker universe exhibits a singular origin. Its future development depends upon the curvature of the spatial sections: spatially flat or hyperboloid universes expand forever and this expansion dilutes the energy density and pressure of the gas, while a universe with compact spherical sections reaches a maximal expansion, after which it reverses its motion and recollapses to a final crunch singularity where the energy density and isotropic pressure diverge. Finally, we analyze the evolution of the universe filled with the collisionless gas once a cosmological constant is included

  6. Detecting leaks in gas-filled pressure vessels using acoustic resonances

    Science.gov (United States)

    Gillis, K. A.; Moldover, M. R.; Mehl, J. B.

    2016-05-01

    We demonstrate that a leak from a large, unthermostatted pressure vessel into ambient air can be detected an order of magnitude more effectively by measuring the time dependence of the ratio p/f2 than by measuring the ratio p/T. Here f is the resonance frequency of an acoustic mode of the gas inside the pressure vessel, p is the pressure of the gas, and T is the kelvin temperature measured at one point in the gas. In general, the resonance frequencies are determined by a mode-dependent, weighted average of the square of the speed-of-sound throughout the volume of the gas. However, the weighting usually has a weak dependence on likely temperature gradients in the gas inside a large pressure vessel. Using the ratio p/f2, we measured a gas leak (dM/dt)/M ≈ - 1.3 × 10-5 h-1 = - 0.11 yr-1 from a 300-liter pressure vessel filled with argon at 450 kPa that was exposed to sunshine-driven temperature and pressure fluctuations as large as (dT/dt)/T ≈ (dp/dt)/p ≈ 5 × 10-2 h-1 using a 24-hour data record. This leak could not be detected in a 72-hour record of p/T. (Here M is the mass of the gas in the vessel and t is the time.)

  7. Gas-filled cell as a narrow bandwidth bandpass filter in the VUV wavelength range

    International Nuclear Information System (INIS)

    We propose a method for spectrally filtering radiation in the VUV wavelength range by means of a monochromator constituted by a cell filled with a resonantly absorbing rare gas. Around particular wavelengths, the gas exhibits narrow-bandwidth absorbing resonances following the Fano profile. In particular, within the photon energy range 60 eV-65 eV, the correlation index of the Fano profiles for the photoionization spectra in Helium is equal to unity, meaning that the minimum of the cross-section is exactly zero. For sufficiently large column density in the gas cell, the spectrum of the incoming radiation will be attenuated by the background cross-section of many orders of magnitude, except for those wavelengths close to the point where the cross-section is zero. Remarkable advantages of a gas monochromator based on this principle are simplicity, efficiency and narrow-bandwidth. A gas monochromator installed in the experimental hall of a VUV SASE FEL facility would enable the delivery of a single-mode VUV laser beam. The design is identical to that of already existing gas attenuator systems for VUV or X-ray FELs. We present feasibility study and exemplifications for the FLASH facility in the VUV regime. (orig.)

  8. Study of high pressure gas filled RF cavities for muon collider

    CERN Document Server

    Yonehara, Katsuya

    2015-01-01

    Muon collider is a considerable candidate of the next-generation high-energy lepton collider machine. Operating an RF cavity in a multi-Tesla magnet is a critical requirement in a muon accelerator and a cooling channel. However, the maximum RF gradient in a vacuum RF cavity is strongly limited by an external magnetic field. Dense hydrogen gas filled RF cavity has been proposed since it is functional of generating a high RF accelerating gradient in a strong magnetic field and making an ionization cooling process at the same time. A critical issue of the cavity is a beam- induced plasma that consumes a considerable amount of RF power. The gas filled RF test cell was made and measured the RF loading due to a beam-induced plasma by using an intense proton beam at Fermilab. By doping an electronegative gas in dense hydrogen, the plasma loading effect is significantly mitigated. The result shows that the cavity is functional with a muon collider beam. Recent progress is shown in this presentation.

  9. Design of a radioactive gas sampling system for NESHAP compliance measurements of 41Ar

    International Nuclear Information System (INIS)

    United States Department of Energy facilities are required to comply with the U.S. Environmental Protection Agency, National Emission Standard for Hazardous Air Pollutants (NESHAP) 40 CFR, part 61, subpart H. Compliance generally requires confirmatory measurements of emitted radionuclides. Although a number of standard procedures exist for extractive sampling of particle-associated radionuclides, sampling approaches for radioactive gases are less defined. Real-time, flow-through sampling of radioactive gases can be done when concentrations are high compared to interferences from background radiation. Cold traps can be used to collect and concentrate condensible effluents in applications where cryogenic conditions can be established and maintained. Commercially available gas-sampling cylinders can be used to capture grab samples of contaminated air under ambient or compressed conditions, if suitable sampling and control hardware are added to the cylinders. The purpose of the current study was to develop an efficient and compact set of sampling and control hardware for use with commercially available gas-sampling cylinders, and to demonstrate its use in NESHAP compliance testing of 41Ar at two experimental research reactors

  10. The Detection System of the Dubna Gas-Filled Recoil Separator

    International Nuclear Information System (INIS)

    The Dubna Gas-filled Recoil Separator, operated at the U400 cyclotron at the Flerov Laboratory of Nuclear Reactions, is one of the most efficient existing separator systems used to separate heavy products of the complete fusion nuclear reactions. The system of detecting the compound nuclei α - decay sequences and spontaneous fission events, data processing, read-out and accumulation is described. The present system was successfully applied in our experiments aimed at the synthesis of superheavy elements with Z = 116 and Z = 114. (author)

  11. Simulation of laser-plasma interaction experiments with gas-filled hohlraums on the LIL facility

    Science.gov (United States)

    Loiseau, P.; Masson-Laborde, P.-E.; Teychenné, D.; Monteil, M.-C.; Casanova, M.; Marion, D.; Tran, G.; Huser, G.; Rousseaux, C.; Hüller, S.; Héron, A.; Pesme, D.

    2016-03-01

    Laser-plasma interaction is a major issue for achieving ignition in inertial confinement fusion schemes, and still a major concern for the upcoming french laser mégajoule (LMJ) program. In order to mitigate the deleterious effects due to laser-plasma instabilities (LPI), clearly evidenced during the recent US National Ignition Campaign conducted on the National Ignition Facility, we use the LIL facility as a demonstrator for LPI studies. In this article, we focus on preliminary results regarding the propagation of a typical LMJ quadruplet through gas-filled hohlraums. Results on hohlraum energetics will then be discussed.

  12. Development of a Gas Filled Magnet spectrometer within the FIPPS project

    Science.gov (United States)

    Chebboubi, A.; Kessedjian, G.; Faust, H.; Blanc, A.; Jentschel, M.; Köster, U.; Materna, T.; Méplan, O.; Sage, C.; Serot, O.

    2016-06-01

    The Fission Product Prompt γ -ray Spectrometer, FIPPS, is under development to enable prompt γ -ray spectroscopy correlated with fission fragment identification. This will open new possibilities in the study of fission and of nuclear structure of neutron rich nuclei. FIPPS will consist of an array of γ and neutron detectors coupled with a fission fragment filter. The chosen solution for the filter is a Gas Filled Magnet (GFM). Both experimental and modeling work was performed in order to extract the key parameters of such a device and design the future GFM of the FIPPS project. Experiments performed with a GFM behind the LOHENGRIN spectrometer demonstrated the capability of additional beam purification.

  13. Focal spot size predictions for beam transport through a gas-filled reactor

    International Nuclear Information System (INIS)

    Results from calculations of focal spot size for beam transport through a gas-filled reactor are summarized. In the converging beam mode, we find an enlargement of the focal spot due to multiple scattering and zeroth order self-field effects. This enlargement can be minimized by maintaining small reactors together with a careful choice of the gaseous medium. The self-focused mode, on the other hand, is relatively insensitive to the reactor environment, but is critically dependent upon initial beam quality. This requirement on beam quality can be significantly eased by the injection of an electron beam of modest current from the opposite wall

  14. Tunable frequency-up/down conversion in gas-filled hollow-core photonic crystal fibers.

    Science.gov (United States)

    Saleh, Mohammed F; Biancalana, Fabio

    2015-09-15

    Based on the interplay between photoionization and Raman effects in gas-filled photonic crystal fibers, we propose a new optical device to control frequency conversion of ultrashort pulses. By tuning the input-pulse energy, the output spectrum can be either down-converted, up-converted, or even frequency-shift compensated. For low input energies, the Raman effect is dominant and leads to a redshift that increases linearly during propagation. For larger pulse energies, photoionization starts to take over the frequency-conversion process and induces a strong blueshift. The fiber-output pressure can be used as an additional degree of freedom to control the spectrum shift. PMID:26371900

  15. A giant gas-filled abdominal mass in an elderly female: A case report

    Institute of Scientific and Technical Information of China (English)

    Hoi Man Deon Chong; Fung Yee Janet Lee; Anthony Lo; Chak Man Jimmy Li

    2011-01-01

    We report an extremely rare case of gas-filled abdomi?nal mass caused by an ovarian teratoma fistulating to the sigmoid colon. The patient was an 85-year-old female, who presented with severe abdominal disten?sion. Urgent computed tomography scan showed a huge abdominal mass with air fluid level and fecal matter inside. Communication between the mass and the sigmoid colon was suspected. She underwent emergency laparotomy. The mass was resected with the involved segment of colon. Pathology confirmed squamous cell carcinoma arising from mature cystic teratoma of the ovary.

  16. New Hadron Monitor By Using A Gas-Filled RF Resonator

    Energy Technology Data Exchange (ETDEWEB)

    Yonehara, Katsuya [Fermilab; Fasce, Giorgio [ECONA, Rome; Flanagan, Gene [MUONS Inc., Batavia; Johnson, Rolland [MUONS Inc., Batavia; Tollestrup, Alvin [Fermilab; Zwaska, Robert [Fermilab

    2015-05-01

    It is trend to build an intense neutrino beam facility for the fundamental physics research, e.g. LBNF at Fermilab, T2K at KEK, and CNGS at CERN. They have investigated a hadron monitor to diagnose the primary/secondary beam quality. The existing hadron monitor based on an ionization chamber is not robust in the high-radiation environment vicinity of MW-class secondary particle production targets. We propose a gas-filled RF resonator to use as the hadron monitor since it is simple and hence radiation robust in this environment. When charged particles pass through the resonator they produce ionized plasma via the Coulomb interaction with the inert gas. The beam-induced plasma changes the permittivity of inert gas. As a result, a resonant frequency in the resonator shifts with the amount of ionized electrons. The radiation sensitivity is adjustable by the inert gas pressure and the RF amplitude. The hadron profile will be reconstructed with a tomography technique in the hodoscope which consists of X, Y, and theta layers by using a strip-shaped gas resonator. The sensitivity and possible system design will be shown in this presentation.

  17. Process and device for subdividing a glass tube filled with a radioactive gas

    International Nuclear Information System (INIS)

    A process is described for subdividing into individual sealed segments an elongated glass tube coated internally with a luminescent material and filled with a radioactive gas, this tube having a longitudinal axis. It consists in directing a focused laser beam on to the surface of the tube in an ambient atmosphere with a pressure greater than that of the gas in the tube and to create a relative, repetitive and alternating movement between the laser beam and the surface of the tube. This movement is transversal to the longitudinal axis of the tube, so as to heat and soften the tube along a cutting line until the tube divides and presents new ends where it contracts, causing these ends to seal up

  18. The axial symmetric vibrations of cylindrical shell, filled by the flowing Gas-Liquid mixture

    Directory of Open Access Journals (Sweden)

    Grigoryan Sh.H.

    2011-09-01

    Full Text Available The problem of axial symmetric self–vibrations of the infinite long shell, filled by flowing gas bubbles of large and small sizes in fluid mixture is considered. The subsonic and supersonic regimes of the mixture flow are discussed. For vibration frequencies of the system under consideration are shown that shell frequencies with big bubbles–liquids mixture exceed the frequencies of system of with small gas bubbles–liquid mixture. In subsonic regime increasing of shell thickness brings to increasing of shell frequencies, as in case of shell with pure fluid. In subsonic regime the frequencies are increasing with decreasing of the flowing velocity, on the contrary, brings to decreasing of frequencies, similar to the case of shell with the pure fluid.

  19. Characteristics of a high pressure gas proportional counter filled with xenon

    Science.gov (United States)

    Sakurai, H.; Ramsey, B. D.

    1991-01-01

    The characteristics of a conventional cylindrical geometry proportional counter filled with high pressure xenon gas up to 10 atm. were fundamentally investigated for use as a detector in hard X-ray astronomy. With a 2 percent methane gas mixture the energy resolutions at 10 atm. were 9.8 percent and 7.3 percent for 22 keV and 60 keV X-rays, respectively. From calculations of the Townsend ionization coefficient, it is shown that proportional counters at high pressure operate at weaker reduced electric field than low pressure counters. The characteristics of a parallel grid proportional counter at low pressure showed similar pressure dependence. It is suggested that this is the fundamental reason for the degradation of resolution observed with increasing pressure.

  20. Gas Filled RF Resonator Hadron Beam Monitor for Intense Neutrino Beam Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Yonehara, Katsuya [Fermilab; Abrams, Robert [MUONS Inc., Batavia; Dinkel, Holly [U. Missouri, Columbia; Freemire, Ben [IIT, Chicago; Johnson, Rolland [MUONS Inc., Batavia; Kazakevich, Grigory [MUONS Inc., Batavia; Tollestrup, Alvin [Fermilab; Zwaska, Robert [Fermilab

    2016-06-01

    MW-class beam facilities are being considered all over the world to produce an intense neutrino beam for fundamental particle physics experiments. A radiation-robust beam monitor system is required to diagnose the primary and secondary beam qualities in high-radiation environments. We have proposed a novel gas-filled RF-resonator hadron beam monitor in which charged particles passing through the resonator produce ionized plasma that changes the permittivity of the gas. The sensitivity of the monitor has been evaluated in numerical simulation. A signal manipulation algorithm has been designed. A prototype system will be constructed and tested by using a proton beam at the MuCool Test Area at Fermilab.

  1. Characterizing passive coherent population trapping resonance in a cesium vapor cell filled with neon buffer gas

    International Nuclear Information System (INIS)

    We present a pair of phase-locked lasers with a 9.2-GHz frequency difference through the injection locking of a master laser to the RF-modulation sideband of a slave diode laser. Using this laser system, a coherent population trapping (CPT) signal with a typical linewidth of ∼ 182 Hz is obtained in a cesium vapor cell filled with 30 Torr (4 kPa) of neon as the buffer gas. We investigate the influence of the partial pressure of the neon buffer gas on the CPT linewidth, amplitude, and frequency shift. The results may offer some references for CPT atomic clocks and CPT atomic magnetometers. (atomic and molecular physics)

  2. Feasibility Study of Compact Gas-Filled Storage Ring for 6D Cooling of Muon Beams

    International Nuclear Information System (INIS)

    The future of elementary particle physics in the USA depends in part on the development of new machines such as the International Linear Collider, Muon Collider and Neutrino Factories which can produce particle beams of higher energy, intensity, or particle type than now exists. These beams will enable the continued exploration of the world of elementary particles and interactions. In addition, the associated development of new technologies and machines such as a Muon Ring Cooler is essential. This project was to undertake a feasibility study of a compact gas-filled storage ring for 6D cooling of muon beams. The ultimate goal, in Phase III, was to build, test, and operate a demonstration storage ring. The preferred lattice for the storage ring was determined and dynamic simulations of particles through the lattice were performed. A conceptual design and drawing of the magnets were made and a study of the RF cavity and possible injection/ejection scheme made. Commercial applications for the device were investigated and the writing of the Phase II proposal completed. The research findings conclude that a compact gas-filled storage ring for 6D cooling of muon beams is possible with further research and development

  3. Mapping the Ionization State of Laser-Irradiated Ar Gas Jets With Multi-Wavelength Monochromatic X-Ray Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kugland, N L; Doppner, T; Kemp, A; Schaeffer, D; Glenzer, S H; Niemann, C

    2010-04-08

    Two-dimensional monochromatic images of fast-electron stimulated Ar K{alpha} and He-{alpha} x-ray self-emission have recorded a time-integrated map of the extent of Ar{sup {approx}6+} and Ar{sup 16+} ions, respectively, within a high density (10{sup 20} cm{sup -3} atomic density) Ar plasma. This plasma was produced by irradiating a 2 mm wide clustering Ar gas jet with an ultra-high intensity (10{sup 19} W/cm{sup 2}, 200 fs) Ti:Sapphire laser operating at 800 nm. Spherically bent quartz crystals in the 200 (for K{alpha}) and 201 (for He-{alpha}) planes were used as near-normal incidence reflective x-ray optics. We see that a large (830 {micro}m long) region of plasma emits K{alpha} primarily along the laser axis, while the He-{alpha} emission is confined to smaller hot spot (230 {micro}m long) region that likely corresponds to the focal volume of the f/8 laser beam. X-ray spectra from a Bragg spectrometer operating in the von Hamos geometry, which images in one dimension, indicate that the centroids of the K{alpha} and He-{alpha} emission regions are separated by approximately 330 {micro}m along the laser axis.

  4. Developments for transactinide chemistry experiments behind the gas-filled separator TASCA

    International Nuclear Information System (INIS)

    Topic of this thesis is the development of experiments behind the gas-filled separator TASCA (TransActinide Separator and Chemistry Apparatus) to study the chemical properties of the transactinide elements. In the first part of the thesis, the electrodepositions of short-lived isotopes of ruthenium and osmium on gold electrodes were studied as model experiments for hassium. From literature it is known that the deposition potential of single atoms differs significantly from the potential predicted by the Nernst equation. This shift of the potential depends on the adsorption enthalpy of therndeposited element on the electrode material. If the adsorption on the electrode-material is favoured over the adsorption on a surface made of the same element as the deposited atom, the electrode potential is shifted to higher potentials. This phenomenon is called underpotential deposition. Possibilities to automatize an electro chemistry experiment behind the gas-filled separator were explored for later studies with transactinide elements. The second part of this thesis is about the in-situ synthesis of transition-metal-carbonyl complexes with nuclear reaction products. Fission products of uranium-235 and californium-249 were produced at the TRIGA Mainz reactor and thermalized in a carbon-monoxide containing atmosphere. The formed volatile metal-carbonyl complexes could be transported in a gas-stream. Furthermore, short-lived isotopes of tungsten, rhenium, osmium, and iridium were synthesised at the linear accelerator UNILAC at GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt. The recoiling fusion products were separated from the primary beam and the transfer products in the gas-filled separator TASCA. The fusion products were stopped in the focal plane of TASCA in a recoil transfer chamber. This chamber contained a carbon-monoxide - helium gas mixture. The formed metal-carbonyl complexes could be transported in a gas stream to various experimental setups. All

  5. Expansion characteristics of twin combustion gas jets with high pressure in cylindrical filling liquid chamber

    Institute of Scientific and Technical Information of China (English)

    薛晓春; 余永刚; 张琦

    2013-01-01

    To deal with the problem of how to control the interior ballistic stability in the bulk-loaded liquid propellant gun, the expansion and mixing process of the twin combustion-gas jets with high temperature and pressure in a liquid medium is studied in the cylindrical filling liquid chamber. A series of the jet expansion shapes is obtained by using a high-speed photographic system. The influences of the jet pressure on the jet expansion shape are discussed. Based on the experiments, the three-dimensional mathematical model is established. The expansion processes of the twin gas jets in the liquid medium are simulated by means of fluent to get the pressure, density, temperature, velocity contours and evolutionary process of vortices. Results show that the jet external outline and tops are all irregular. The Kelvin-Helmholtz instability is shown in the whole expansion process. The numerical simulation results of the axial displacement of the twin gas jets in liquid agree well with the experiment.

  6. GeV-scale electron acceleration in a gas-filled capillary discharge waveguide

    International Nuclear Information System (INIS)

    We report experimental results on laser-driven electron acceleration with low divergence. The electron beam was generated by focussing 750 mJ, 42 fs laser pulses into a gas-filled capillary discharge waveguide at electron densities in the range between 1018 and 1019 cm-3. Quasi-monoenergetic electron bunches with energies as high as 500 MeV have been detected, with features reaching up to 1 GeV, albeit with large shot-to-shot fluctuations. A more stable regime with higher bunch charge (20-45 pC) and less energy (200-300 MeV) could also be observed. The beam divergence and the pointing stability are around or below 1 mrad and 8 mrad, respectively. These findings are consistent with self-injection of electrons into a breaking plasma wave

  7. Development of a Gas Filled Magnet spectrometer coupled with the Lohengrin spectrometer for fission study

    Directory of Open Access Journals (Sweden)

    Materna T.

    2013-03-01

    Full Text Available The accurate knowledge of the fission of actinides is necessary for studies of innovative nuclear reactor concepts. The fission yields have a direct influence on the evaluation of the fuel inventory or the reactor residual power after shutdown. A collaboration between the ILL, LPSC and CEA has developed a measurement program on fission fragment distributions at ILL in order to measure the isotopic and isomeric yields. The method is illustrated using the 233U(n,f98Y reaction. However, the extracted beam from the Lohengrin spectrometer is not isobaric ions which limits the low yield measurements. Presently, the coupling of the Lohengrin spectrometer with a Gas Filled Magnet (GFM is studied at the ILL in order to define and validate the enhanced purification of the extracted beam. This work will present the results of the spectrometer characterisation, along with a comparison with a dedicated Monte Carlo simulation especially developed for this purpose.

  8. Structural Integrity of Gas-Filled Composite Overwrapped Pressure Vessels Subjected to Orbital Debris Impact

    Science.gov (United States)

    Telichev, Igor; Cherniaev, Aleksandr

    Gas-filled pressure vessels are extensively used in spacecraft onboard systems. During operation on the orbit they exposed to the space debris environment. Due to high energies they contain, pressure vessels have been recognized as the most critical spacecraft components requiring protection from orbital debris impact. Major type of pressurized containers currently used in spacecraft onboard systems is composite overwrapped pressure vessels (COPVs) manufactured by filament winding. In the present work we analyze the structural integrity of vessels of this kind in case of orbital debris impact at velocities ranging from 2 to 10 km/s. Influence of such parameters as projectile energy, shielding standoff, internal pressure and filament winding pattern on COPVs structural integrity has been investigated by means of numerical and physical experiments.

  9. Fast PC-based data acquisition system for gas-filled position sensitive detectors

    International Nuclear Information System (INIS)

    The high flux of the new generation of synchrotron radiation sources requires fast position sensitive detectors with high count rate data acquisition systems capability. Though the local count rate in a gas-filled position-sensitive detector is limited by the space charge effect, the integral rate will increase with the area of the detector. Thus, more than several 106 events per second can be achieved. Therefore, we developed a new PC-based histogramming and control interface (HCl) with an intrinsic dead time lower than 200 ns for linear and area X-ray detectors for time-resolved measurement applications. An overview of the complete acquisition system including a fast time-to-digital converter and image processing software will be given. The design principles and operating characteristics including experimental results obtained with a 100 mm linear delay-line detector at the SAXS beamline 5.2 in Elettra (Trieste) will be presented. (orig.)

  10. Convergent ablation measurements of plastic ablators in gas-filled rugby hohlraums on OMEGA

    Science.gov (United States)

    Casner, A.; Jalinaud, T.; Masse, L.; Galmiche, D.

    2015-10-01

    Indirect-drive implosions experiments were conducted on the Omega Laser Facility to test the performance of uniformly doped plastic ablators for Inertial Confinement Fusion. The first convergent ablation measurements in gas-filled rugby hohlraums are reported. Ignition relevant limb velocities in the range from 150 to 300 μm .n s-1 have been reached by varying the laser drive energy and the initial capsule aspect ratio. The measured capsule trajectory and implosion velocity are in good agreement with 2D integrated simulations and a zero-dimensional modeling of the implosions. We demonstrate experimentally the scaling law for the maximum implosion velocity predicted by the improved rocket model [Y. Saillard, Nucl. Fusion 46, 1017 (2006)] in the high-ablation regime case.

  11. Tunable frequency-up/down conversion in gas-filled hollow-core photonic crystal fibers

    CERN Document Server

    Saleh, Mohammed F

    2015-01-01

    Based on the interplay between photoionization and Raman effect in gas-filled photonic crystal fibers, we propose a new optical device to control frequency-conversion of ultrashort pulses. By tuning the input-pulse energy, the output spectrum can be either down-converted, up-converted, or even frequency-shift compensated. For low input energies, Raman effect is dominant and leads to a redshift that increases linearly during propagation. For larger pulse energies, photoionization starts to take over the frequency conversion process, and induces a strong blueshift. We have found also that by changing the fiber-output pressure the pulse spectrum blueshifts, providing an additional degree of freedom in the design.

  12. A new focal plane detector for the gas-filled separator TASCA

    International Nuclear Information System (INIS)

    Superheavy elements (SHE) exist solely because of enhanced nuclear stability due to shell effects. The production cross sections for the synthesis of SHE decrease continuously, thus, exploration of SHE nuclei is close to the border of present technical limitation. To increase the efficiency and sensitivity in SHE experiments, highly efficient recoil separators with state-of-the-art detection systems are required. In the framework of this thesis, the new focal plane detection system with the dedicated electronics have been developed for the gas-filled recoil separator TASCA at the GSI Helmholtzzentrum for Schwerionenforschung GmbH. The new detection system has been successfully used in recent experiments on synthesis of the E114.

  13. Nitriding molybdenum: Effects of duration and fill gas pressure when using 100-Hz pulse DC discharge technique

    International Nuclear Information System (INIS)

    Molybdenum is nitrided by a 100-Hz pulsed DC glow discharge technique for various time durations and fill gas pressures to study the effects on the surface properties of molybdenum. X-ray diffractometry (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM) are used for the structural and morphological analysis of the nitrided layers. Vickers' microhardness tester is utilized to investigate surface microhardness. Phase analysis shows the formation of more molybdenum nitride molecules for longer nitriding durations at fill gas pressures of 2 mbar and 3 mbar (1 bar = 105 Pa). A considerable increase in surface microhardness (approximately by a factor of 2) is observed for longer duration (10 h) and 2-mbar pressure. Longer duration (10 h) and 2-mbar fill gas pressure favors the formation of homogeneous, smooth, hard layers by the incorporation of more nitrogen. (physics of gases, plasmas, and electric discharges)

  14. Formation of single-wall carbon nanotubes in Ar and nitrogen gas atmosphere by using laser furnace technique

    Science.gov (United States)

    Suzuki, S.; Asai, N.; Kataura, H.; Achiba, Y.

    2007-07-01

    The formation of single-wall carbon nanotubes (SWNTs) by using laser vaporization technique in different ambient gas atmosphere was investigated. SWNTs were prepared with Rh/Pd (1.2/1.2 atom%)-carbon composite rod in Ar and nitrogen gas atmosphere, respectively. Raman spectra of raw carbon materials including SWNTs and photoluminescence mapping of dispersed SWNTs in a surfactant solution demonstrate that the diameter distribution of SWNTs prepared in Ar atmosphere is narrower than those obtained by using CVD technique (e.g. HiPco nanotube), even when the ambient temperature is as high as 1150 ?C. It was also found that nitrogen atmosphere gives wider diameter distribution of SWNTs than that obtained with Ar atmosphere. Furthermore, the relative yield of fullerenes (obtained as byproducts) is investigated by using HPLC (high-performance liquid chromatography) technique. It was found that the relative yield of higher fullerenes becomes lower, when nitrogen is used as an ambient gas atmosphere. Based on these experimental findings, a plausible formation mechanism of SWNTs is discussed.

  15. Mechanism of Hydrogenated Microcrystalline Si Film Deposition by Magnetron Sputtering Employing a Si Target and H2/Ar Gas Mixture

    Science.gov (United States)

    Fukaya, Kota; Tabata, Akimori; Sasaki, Koichi

    2009-03-01

    The mechanism of hydrogenated microcrystalline silicon (µc-Si:H) film deposition by magnetron sputtering employing a Si target and H2/Ar gas mixture has been investigated by measuring Si and H atom densities in the gas phase by laser-induced fluorescence spectroscopy. The crystalline volume fraction of the film correlated positively with H atom density. The variation in Si atom density indicated the increase in sputtering yield from the Si target in the H2/Ar discharge. The surface of the Si target immersed in the H2/Ar discharge was hydrogenated. Therefore, it is reasonable to expect the production of SiHx molecules (typically SiH4) from the hydrogenated Si target via reactive ion etching. Since SiHx molecules produced from the target may function as a deposition precursor, the mechanism of µc-Si:H film deposition is considered to be similar to that of plasma-enhanced chemical vapor deposition (PECVD) employing a SiH4/H2 gas mixture. The advantage of magnetron sputtering deposition over PECVD is the production of SiHx molecules without using toxic, explosive SiH4.

  16. MAG orbital welding with cover gas filling wire electrodes; MAG-Orbitalschweissen mit gasgeschuetzten Fuelldrahtelektroden

    Energy Technology Data Exchange (ETDEWEB)

    Engindeniz, E. [Oerlikon Schweisstechnik GmbH, Eisenberg (Germany)

    1995-12-31

    Pipelines made of steel are required to an increasing extent worldwide in the field of district heating and water supply and for the transport of petroleum, natural gas etc. In laying them, circular welds are produced by means of various welding processes. While EH welding with cellulose rod electrodes continues to be the dominant variant, the importance of suitable MAG orbital techniques is increasing by leaps and bounds. Economy and quality aspects are mainly decisive for this. Another reason to be mentioned, apart form the reproduceability of the quality of welds by mechanisation is humanisation of the workplace. At present MAG orbital welding has taken up a firm position in pipeline construction. The variant with cover gas filling wire electrodes on which this article reports, should be particularly emphasised here. The process is suitable for producing filling and top layers in the position sequence PE-PF-PA. Either EH or TIG welding can be considered for carrying out the root and hot pass, where one must mention that the first experiments on the mechanized welding of the root by the MAG process have been successfully concluded. (orig.) [Deutsch] Bereich der Fernwaerm Bereich der Fernwaerme sowie Wasserversorgung und fuer den Transport von Erdoel, -gas etc. werden weltweit in zunehendemendem Masse Rohrleitungen aus Stahl benoetigt. Bei der Verlegung erfolgt die Ausfuehrung der Rundnaehte ittels verschiedener Schmittels verschiedener Schmelzschweissverfahren. Waehrend das EH-Schweissen it Zellulose-Stabelektroden weiterhin als domit Zellulose-Stabelektroden weiterhin als dominierende e Variante gilt, ni mmt die Bedeutung geeigneter MAG-Orbitaltechnologien rasant zu. Fuer diese Entwicklung sind in erster Linie Wirtschaftlichkeits- und Qualitaetsaspekte assgebend. Als weiterer Grund ist neben der Reproduzierbarkeit der Nahtguete durch die Mechanisierung die Humassgebend. Als weiterer Grund ist neben der Reproduzierbarkeit der Nahtguete durch die Mechanisierung

  17. Mapping the ionization state of laser-irradiated Ar gas jets with multiwavelength monochromatic x-ray imaging

    International Nuclear Information System (INIS)

    Two-dimensional monochromatic images of fast-electron stimulated Ar Kα and He-α x-ray self-emission have recorded a time-integrated map of the extent of Ar≅6+ and Ar16+ ions, respectively, within a high density (1020 cm-3 atomic density) Ar plasma. This plasma was produced by irradiating a 2 mm wide clustering Ar gas jet with an ultrahigh intensity (1019 W/cm2, 50 TW) Ti:sapphire laser operating at 800 nm. Spherically bent quartz crystals in the 200 (for Kα) and 201 (for He-α) planes were used as near-normal incidence reflective x-ray optics. We see that a large (830 μm long) region of plasma emits Kα primarily along the laser axis, while the He-α emission is confined to smaller hot spot (230 μm long) region that likely corresponds to the focal volume of the f/8 laser beam. X-ray spectra from a Bragg spectrometer operating in the von Hamos geometry indicate that the centroids of the Kα and He-α emission regions are separated by approximately 330 μm along the laser axis.

  18. Comparison between large discharges of a gas counter in pure CH4 and in a CH4-Ar mixture

    International Nuclear Information System (INIS)

    Gas discharge characteristics in pure CH4 have been studied in the high gas-multiplication region by using a gas counter with a thick anode wire (50 μm in diameter) and compared with those of the self-quenching streamer (SQS) mode in a CH4-Ar mixture. The results of the first optical observation indicate that the large pulses observed in CH4, whose pulse amplitudes are comparable to those of the SQS mode, are not due to streamer discharges. Instead, a luminous region is observed near the anode wire (r≤0.7 mm) where the electric field is higher than the threshold value for gas multiplication, 104 V/cm. (orig.)

  19. Propagation dynamics of femtosecond laser pulses in a hollow fiber filled with argon: constant gas pressure versus differential gas pressure

    Science.gov (United States)

    Nurhuda, Muhammad; Suda, Akira; Midorikawa, Katsumi; Hatayama, Masatoshi; Nagasaka, Keigo

    2003-09-01

    We investigate the dynamics of femtosecond laser pulses propagating in a hollow fiber filled with argon, through a full numerical solution of the nonlinear Schrödinger equation. The simulation results show that, if the intensity is low and no ionization takes place, the spatial profile of the beam does not change very much so that its propagation model may be simplified to a one-dimensional model. If the intensity is high and ionization takes place, the spatial dynamics as well as temporal dynamics become very complicated because of self-focusing and defocusing. It is found that, for the same value of the B integral, self-focusing inside a hollow fiber can be substantially suspended by a differential gas pressure technique, where the gas pressure is set to be a minimum at the entrance and then increased with the propagation distance. Numerical simulations show that using such a technique, the energy transmitted during propagation inside hollow fiber is significantly enhanced, and the spatial phase is also improved.

  20. Developments for transactinide chemistry experiments behind the gas-filled separator TASCA

    Energy Technology Data Exchange (ETDEWEB)

    Even, Julia

    2011-12-13

    Topic of this thesis is the development of experiments behind the gas-filled separator TASCA (TransActinide Separator and Chemistry Apparatus) to study the chemical properties of the transactinide elements. In the first part of the thesis, the electrodepositions of short-lived isotopes of ruthenium and osmium on gold electrodes were studied as model experiments for hassium. From literature it is known that the deposition potential of single atoms differs significantly from the potential predicted by the Nernst equation. This shift of the potential depends on the adsorption enthalpy of therndeposited element on the electrode material. If the adsorption on the electrode-material is favoured over the adsorption on a surface made of the same element as the deposited atom, the electrode potential is shifted to higher potentials. This phenomenon is called underpotential deposition. Possibilities to automatize an electro chemistry experiment behind the gas-filled separator were explored for later studies with transactinide elements. The second part of this thesis is about the in-situ synthesis of transition-metal-carbonyl complexes with nuclear reaction products. Fission products of uranium-235 and californium-249 were produced at the TRIGA Mainz reactor and thermalized in a carbon-monoxide containing atmosphere. The formed volatile metal-carbonyl complexes could be transported in a gas-stream. Furthermore, short-lived isotopes of tungsten, rhenium, osmium, and iridium were synthesised at the linear accelerator UNILAC at GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt. The recoiling fusion products were separated from the primary beam and the transfer products in the gas-filled separator TASCA. The fusion products were stopped in the focal plane of TASCA in a recoil transfer chamber. This chamber contained a carbon-monoxide - helium gas mixture. The formed metal-carbonyl complexes could be transported in a gas stream to various experimental setups. All

  1. Development of high pressure-high vacuum-high conductance piston valve for gas-filled radiation detectors

    International Nuclear Information System (INIS)

    Gas-filled radiation detectors need gas filling at pressures that range from few cms of mercury to as high as 25kg/cm2 at room temperature. Before gas-filling these detectors require evacuation to a vacuum of the order of ∼1 x 10-5 mbar. For these operations of evacuation and gas filling a system consisting of a vacuum pump with a high vacuum gauge, gas cylinder with a pressure gauge and a valve is used. The valve has to meet the three requirements of compatibility with high-pressure and high vacuum and high conductance. A piston valve suitable for the evacuation and gas filling of radiation detectors has been designed and fabricated to meet the above requirements. The stainless steel body (80mmx160mm overall dimensions) valve with a piston arrangement has a 1/2 inch inlet/outlet opening, neoprene/viton O-ring at piston face and diameter for sealing and a knob for opening and closing the valve. The piston movement mechanism is designed to have minimum wear of sealing O-rings. The valve has been hydrostatic pressure tested up to 75bars and has Helium leak rate of less than 9.6x10-9 m bar ltr/sec in vacuum mode and 2x10-7 mbar ltr/sec in pressure mode. As compared to a commercial diaphragm valve, which needed 3 hours to evacuate a 7 litre chamber to 2.5x10-5 mbar, the new valve achieved vacuum 7.4x10-6mbar in the same time under the same conditions

  2. Development of high pressure-high vacuum-high conductance piston valve for gas-filled radiation detectors

    Science.gov (United States)

    Prasad, D. N.; Ayyappan, R.; Kamble, L. P.; Singh, J. P.; Muralikrishna, L. V.; Alex, M.; Balagi, V.; Mukhopadhyay, P. K.

    2008-05-01

    Gas-filled radiation detectors need gas filling at pressures that range from few cms of mercury to as high as 25kg/cm2 at room temperature. Before gas-filling these detectors require evacuation to a vacuum of the order of ~1 × 10-5 mbar. For these operations of evacuation and gas filling a system consisting of a vacuum pump with a high vacuum gauge, gas cylinder with a pressure gauge and a valve is used. The valve has to meet the three requirements of compatibility with high-pressure and high vacuum and high conductance. A piston valve suitable for the evacuation and gas filling of radiation detectors has been designed and fabricated to meet the above requirements. The stainless steel body (80mm×160mm overall dimensions) valve with a piston arrangement has a 1/2 inch inlet/outlet opening, neoprene/viton O-ring at piston face & diameter for sealing and a knob for opening and closing the valve. The piston movement mechanism is designed to have minimum wear of sealing O-rings. The valve has been hydrostatic pressure tested up to 75bars and has Helium leak rate of less than 9.6×10-9 m bar ltr/sec in vacuum mode and 2×10-7 mbar ltr/sec in pressure mode. As compared to a commercial diaphragm valve, which needed 3 hours to evacuate a 7 litre chamber to 2.5×10-5 mbar, the new valve achieved vacuum 7.4×10-6mbar in the same time under the same conditions.

  3. Design and fabrication of a data logger for atmospheric pressure, temperature and relative humidity for gas-filled detector development

    CERN Document Server

    Sahu, S; Rudra, Sharmili; Biswas, S; Mohanty, B; Sahu, P K

    2015-01-01

    A novel instrument has been developed to monitor and record the ambient pa- rameters such as temperature, atmospheric pressure and relative humidity. These parameters are very essential for understanding the characteristics such as gain of gas filled detectors like Gas Electron Multiplier (GEM) and Multi Wire Propor- tional Counter (MWPC). In this article the details of the design, fabrication and operation processes of the device has been presented.

  4. A new method to remove helium impurity from a xenon filled detector with a membrane gas separator

    International Nuclear Information System (INIS)

    A new method to remove helium impurity from the X-ray detectors filled with xenon gas is developed. To separate helium gas from xenon their difference in permeability through a membrane is used. In this article, measurements on permeabilities for helium, argon, xenon and methane are presented. An application of this separator to the actual X-ray detectors, which are parts of the VENUS transition radiation detector (TRD), is also discussed. (orig.)

  5. Dissociative recombination of rare gas hydride ions: II. ArH+

    International Nuclear Information System (INIS)

    A storage ring measurement of the rate coefficient for the production of neutral Ar in e + ArH+ collisions is described. It is found that the recombination rate is too small to measure at low centre-of-mass energies but the combined rate coefficient for dissociative recombination and dissociative excitation increases above 2.5 eV displaying peaks centred at 7.5 eV, 16 and 26 eV. Calculated potential energy curves for the ground and excited states of ArH+ are presented and these aid in the elucidation of the recombination and excitation processes observed at higher energies. The implications for plasma modelling are discussed. (letter to the editor)

  6. Simulation for Large-Area, Inductively-Coupled Plasma Systems Using an Ar/Cl2 Gas Mixture.

    Science.gov (United States)

    Oh, Seon-Geun; Lee, Young-Jun; Jeon, Jae-Hong; Kim, Young-Jin; Seo, Jong-Hyun; Choe, Hee-Hwan

    2015-11-01

    As research and development of high-performance devices are becoming increasingly important in the flat panel display industry, new structures and processes are essential to improve the performance of the TFT backplane. Also, high-density plasma systems are needed for new device fabrications. Chlorine-based, inductively-coupled plasma systems are widely used for highly-selective, anisotropic etching of polysilicon layers. In this paper, a plasma simulation for a large-area ICP system (8th glass size and 9 planar antenna set) was conducted using Ar/Cl2 gas. Transport models and Maxwell Equations were applied to calculate the plasma parameters such as electron density, electron temperature and electric potential. In addition, the spatial distribution of ions such as Ar+, Cl2+, Cl-, Cl+ were investigated respectively. PMID:26726552

  7. Portable optical frequency standard based on sealed gas-filled hollow-core fiber using a novel encapsulation technique

    DEFF Research Database (Denmark)

    Triches, Marco; Brusch, Anders; Hald, Jan

    2015-01-01

    A portable stand-alone optical frequency standard based on a gas-filled hollow-core photonic crystal fiber is developed to stabilize a fiber laser to the 13C2H2 P(16) (ν1 + ν3) transition at 1542 nm using saturated absorption. A novel encapsulation technique is developed to permanently seal the h...

  8. Preparation and characterization of gas-filled liposomes: can they improve oil recovery?

    Science.gov (United States)

    Vangala, Anil; Morris, Robert; Bencsik, Martin; Perrie, Yvonne

    2007-01-01

    Although well known for delivering various pharmaceutical agents, liposomes can be prepared to entrap gas rather than aqueous media and have the potential to be used as pressure probes in magnetic resonance imaging (MRI). Using these gas-filled liposomes (GFL) as tracers, MRI imaging of pressure regions of a fluid flowing through a porous medium could be established. This knowledge can be exploited to enhance recovery of oil from the porous rock regions within oil fields. In the preliminary studies, we have optimized the lipid composition of GFL prepared using a simple homogenization technique and investigated key physico-chemical characteristics (size and the physical stability) and their efficacy as pressure probes. In contrast to the liposomes possessing an aqueous core which are prepared at temperatures above their phase transition temperature (T(c)), homogenization of the phospholipids such as 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) or 1,2-distearoyl-sn-glycero-3-phosphocoline (DSPC) in aqueous medium below their T(c) was found to be crucial in formation of stable GFL. DSPC based preparations yielded a GFL volume of more than five times compared to their DPPC counter part. Although the initial vesicle sizes of both DSPC and DPPC based GFL were about 10 microm, after 7 days storage at 25 degrees C, the vesicle sizes of both formulations significantly (p surfactant, stearylamine, at a molar ratio of 0.25 or 0.125. Interestingly, the zeta potential values remained around neutrality at both stearylamine ratios suggesting the cationic surfactant was not incorporated within the bilayers of the GFL. Microscopic analysis of GFL confirmed the presence of spherical structures with a size distribution between 1-8 microm. This study has identified that DSPC based GFL in aqueous medium dispersed in 2% w/v methyl cellulose although yielded higher vesicle sizes over time were most stable under high pressures exerted in MRI. PMID:18027246

  9. Standard practice for examination of seamless, gas-filled, steel pressure vessels using angle beam ultrasonics

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This practice describes a contact angle-beam shear wave ultrasonic technique to detect and locate the circumferential position of longitudinally oriented discontinuities and to compare the amplitude of the indication from such discontinuities to that of a specified reference notch. This practice does not address examination of the vessel ends. The basic principles of contact angle-beam examination can be found in Practice E 587. Application to pipe and tubing, including the use of notches for standardization, is described in Practice E 213. 1.2 This practice is appropriate for the ultrasonic examination of cylindrical sections of gas-filled, seamless, steel pressure vessels such as those used for the storage and transportation of pressurized gasses. It is applicable to both isolated vessels and those in assemblies. 1.3 The practice is intended to be used following an Acoustic Emission (AE) examination of stacked seamless gaseous pressure vessels (with limited surface scanning area) described in Test Met...

  10. Heavy ion beam propagation through a gas-filled chamber for inertial confinement fusion

    International Nuclear Information System (INIS)

    The work presented here evaluates the dynamics of a beam of heavy ions propagating through a chamber filled with gas. The motivation for this research stems from the possibility of using heavy ion beams as a driver in inertial confinement fusion reactors for the purpose of generating electricity. Such a study is important in determining the constraints on the beam which limit its focus to the small radius necessary for the ignition of thermonuclear microexplosions which are the source of fusion energy. Nuclear fusion is the process of combining light nuclei to form heavier ones. One possible fusion reaction combines two isotopes of hydrogen, deuterium and tritium, to form an alpha particle and a neutron, with an accompanying release of ∼17.6 MeV of energy. Generating electricity from fusion requires that we create such reactions in an efficient and controlled fashion, and harness the resulting energy. In the inertial confinement fusion (ICF) approach to energy production, a small spherical target, a few millimeters in radius, of deuterium and tritium fuel is compressed so that the density and temperature of the fuel are high enough, ∼200 g/cm3 and ∼20 keV, that a substantial number of fusion reactions occur; the pellet microexplosion typically releases ∼350 MJ of energy in optimized power plant scenarios

  11. Convergent ablation measurements with gas-filled rugby hohlraum on OMEGA

    Science.gov (United States)

    Casner, A.; Jalinaud, T.; Galmiche, D.

    2016-03-01

    Convergent ablation experiments with gas-filled rugby hohlraum were performed for the first time on the OMEGA laser facility. A time resolved 1D streaked radiography of capsule implosion is acquired in the direction perpendicular to hohlraum axis, whereas a 2D gated radiography is acquired at the same time along the hohlraum axis on a x-ray framing camera. The implosion trajectory has been measured for various kinds of uniformly doped ablators, including germanium-doped and silicon-doped polymers (CH), at two different doping fraction (2% and 4% at.). Our experiments aimed also at measuring the implosion performance of laminated capsules. A laminated ablator is constituted by thin alternate layers of un-doped and doped CH. It has been previously shown in planar geometry that laminated ablators could mitigate Rayleigh Taylor growth at ablation front. Our results confirm that the implosion of a capsule constituted with a uniform or laminated ablator behaves similarly, in accordance with post-shot simulations performed with the CEA hydrocode FCI2.

  12. Raman-free nonlinear optical effects in high pressure gas-filled hollow core PCF.

    Science.gov (United States)

    Azhar, M; Wong, G K L; Chang, W; Joly, N Y; Russell, P St J

    2013-02-25

    The effective Kerr nonlinearity of hollow-core kagomé-style photonic crystal fiber (PCF) filled with argon gas increases to ~15% of that of bulk silica glass when the pressure is increased from 1 to 150 bar, while the zero dispersion wavelength shifts from 300 to 900 nm. The group velocity dispersion of the system is uniquely pressure-tunable over a wide range while avoiding Raman scattering-absent in noble gases-and having an extremely high optical damage threshold. As a result, detailed and well-controlled studies of nonlinear effects can be performed, in both normal and anomalous dispersion regimes, using only a fixed-frequency pump laser. For example, the absence of Raman scattering permits clean observation, at high powers, of the interaction between a modulational instability side-band and a soliton-created dispersive wave. Excellent agreement is obtained between numerical simulations and experimental results. The system has great potential for the realization of reconfigurable supercontinuum sources, wavelength convertors and short-pulse laser systems. PMID:23481974

  13. Heavy ion beam propagation through a gas-filled chamber for inertial confinement fusion

    Energy Technology Data Exchange (ETDEWEB)

    Barboza, N.O.

    1996-10-01

    The work presented here evaluates the dynamics of a beam of heavy ions propagating through a chamber filled with gas. The motivation for this research stems from the possibility of using heavy ion beams as a driver in inertial confinement fusion reactors for the purpose of generating electricity. Such a study is important in determining the constraints on the beam which limit its focus to the small radius necessary for the ignition of thermonuclear microexplosions which are the source of fusion energy. Nuclear fusion is the process of combining light nuclei to form heavier ones. One possible fusion reaction combines two isotopes of hydrogen, deuterium and tritium, to form an alpha particle and a neutron, with an accompanying release of {approximately}17.6 MeV of energy. Generating electricity from fusion requires that we create such reactions in an efficient and controlled fashion, and harness the resulting energy. In the inertial confinement fusion (ICF) approach to energy production, a small spherical target, a few millimeters in radius, of deuterium and tritium fuel is compressed so that the density and temperature of the fuel are high enough, {approximately}200 g/cm{sup 3} and {approximately}20 keV, that a substantial number of fusion reactions occur; the pellet microexplosion typically releases {approximately}350 MJ of energy in optimized power plant scenarios.

  14. Laser absorption, power transfer, and radiation symmetry during the first shock of inertial confinement fusion gas-filled hohlraum experiments

    Science.gov (United States)

    Pak, A.; Dewald, E. L.; Landen, O. L.; Milovich, J.; Strozzi, D. J.; Berzak Hopkins, L. F.; Bradley, D. K.; Divol, L.; Ho, D. D.; MacKinnon, A. J.; Meezan, N. B.; Michel, P.; Moody, J. D.; Moore, A. S.; Schneider, M. B.; Town, R. P. J.; Hsing, W. W.; Edwards, M. J.

    2015-12-01

    Temporally resolved measurements of the hohlraum radiation flux asymmetry incident onto a bismuth coated surrogate capsule have been made over the first two nanoseconds of ignition relevant laser pulses. Specifically, we study the P2 asymmetry of the incoming flux as a function of cone fraction, defined as the inner-to-total laser beam power ratio, for a variety of hohlraums with different scales and gas fills. This work was performed to understand the relevance of recent experiments, conducted in new reduced-scale neopentane gas filled hohlraums, to full scale helium filled ignition targets. Experimental measurements, matched by 3D view factor calculations, are used to infer differences in symmetry, relative beam absorption, and cross beam energy transfer (CBET), employing an analytic model. Despite differences in hohlraum dimensions and gas fill, as well as in laser beam pointing and power, we find that laser absorption, CBET, and the cone fraction, at which a symmetric flux is achieved, are similar to within 25% between experiments conducted in the reduced and full scale hohlraums. This work demonstrates a close surrogacy in the dynamics during the first shock between reduced-scale and full scale implosion experiments and is an important step in enabling the increased rate of study for physics associated with inertial confinement fusion.

  15. Laser absorption, power transfer, and radiation symmetry during the first shock of inertial confinement fusion gas-filled hohlraum experiments

    International Nuclear Information System (INIS)

    Temporally resolved measurements of the hohlraum radiation flux asymmetry incident onto a bismuth coated surrogate capsule have been made over the first two nanoseconds of ignition relevant laser pulses. Specifically, we study the P2 asymmetry of the incoming flux as a function of cone fraction, defined as the inner-to-total laser beam power ratio, for a variety of hohlraums with different scales and gas fills. This work was performed to understand the relevance of recent experiments, conducted in new reduced-scale neopentane gas filled hohlraums, to full scale helium filled ignition targets. Experimental measurements, matched by 3D view factor calculations, are used to infer differences in symmetry, relative beam absorption, and cross beam energy transfer (CBET), employing an analytic model. Despite differences in hohlraum dimensions and gas fill, as well as in laser beam pointing and power, we find that laser absorption, CBET, and the cone fraction, at which a symmetric flux is achieved, are similar to within 25% between experiments conducted in the reduced and full scale hohlraums. This work demonstrates a close surrogacy in the dynamics during the first shock between reduced-scale and full scale implosion experiments and is an important step in enabling the increased rate of study for physics associated with inertial confinement fusion

  16. Laser absorption, power transfer, and radiation symmetry during the first shock of inertial confinement fusion gas-filled hohlraum experiments

    Energy Technology Data Exchange (ETDEWEB)

    Pak, A.; Dewald, E. L.; Landen, O. L.; Milovich, J.; Strozzi, D. J.; Berzak Hopkins, L. F.; Bradley, D. K.; Divol, L.; Ho, D. D.; MacKinnon, A. J.; Meezan, N. B.; Michel, P.; Moody, J. D.; Moore, A. S.; Schneider, M. B.; Town, R. P. J.; Hsing, W. W.; Edwards, M. J. [Lawrence Livermore National Laboratory, Livermore, California, 94550 (United States)

    2015-12-15

    Temporally resolved measurements of the hohlraum radiation flux asymmetry incident onto a bismuth coated surrogate capsule have been made over the first two nanoseconds of ignition relevant laser pulses. Specifically, we study the P2 asymmetry of the incoming flux as a function of cone fraction, defined as the inner-to-total laser beam power ratio, for a variety of hohlraums with different scales and gas fills. This work was performed to understand the relevance of recent experiments, conducted in new reduced-scale neopentane gas filled hohlraums, to full scale helium filled ignition targets. Experimental measurements, matched by 3D view factor calculations, are used to infer differences in symmetry, relative beam absorption, and cross beam energy transfer (CBET), employing an analytic model. Despite differences in hohlraum dimensions and gas fill, as well as in laser beam pointing and power, we find that laser absorption, CBET, and the cone fraction, at which a symmetric flux is achieved, are similar to within 25% between experiments conducted in the reduced and full scale hohlraums. This work demonstrates a close surrogacy in the dynamics during the first shock between reduced-scale and full scale implosion experiments and is an important step in enabling the increased rate of study for physics associated with inertial confinement fusion.

  17. Domain control of ZnO nanoparticles in a coaxial gas-flow pulse Ar/O2 plasma

    Science.gov (United States)

    Iizuka, Satoru; Shirahata, Hiroki

    2015-09-01

    A limited area, to which ZnO nanoparticles are selectively adhered, is called a domain. Formation of the domain was controlled by using a coaxial gas-flow pulse Ar/O2 plasma. It was found that the mechanism of domain formation was closely related to the initial surface condition of Si substrate. Especially, the cleaning process was crucial. Here, we employed a patterning of the domain by using a fine mesh as a template. The formation processes were estimated by SEM and EDX. The technique developed here will be applied to a selective nanoparticle patterning.

  18. Four-phase fully-coupled mold-filling and solidification simulation for gas porosity prediction in aluminum sand casting

    International Nuclear Information System (INIS)

    The impact of mold-filling and oxide film enclosure on gas porosity in A356 was investigated using a three-phase, fully-coupled, mold-filling and solidification simulation. For the prediction of gas porosity, a fourth hydrogen phase was added. At the solidification front hydrogen is rejected from the solid and accumulates in the melt. Pores nucleate if the solute gas exceeds the solubility limit. Air and melt are separated by a volume of fluid interface and special treatment of the hydrogen phase convection was necessary to limit the hydrogen to the melt. Folding of the melt surface was used as a source for oxide film entrainment. These oxide films were transported with the melt and used as nucleation sites for gas porosity formation. The influence of melt flow due to filling and oxide film distribution was analyzed using a simple 3-block test geometry. The test geometry was cast in A356 and analyzed by computer tomography to validate the porosity prediction.

  19. Four-phase fully-coupled mold-filling and solidification simulation for gas porosity prediction in aluminum sand casting

    Science.gov (United States)

    Jakumeit, J.; Jana, S.; Waclawczyk, T.; Mehdizadeh, A.; Sadiki, A.; Jouani, J.

    2012-07-01

    The impact of mold-filling and oxide film enclosure on gas porosity in A356 was investigated using a three-phase, fully-coupled, mold-filling and solidification simulation. For the prediction of gas porosity, a fourth hydrogen phase was added. At the solidification front hydrogen is rejected from the solid and accumulates in the melt. Pores nucleate if the solute gas exceeds the solubility limit. Air and melt are separated by a volume of fluid interface and special treatment of the hydrogen phase convection was necessary to limit the hydrogen to the melt. Folding of the melt surface was used as a source for oxide film entrainment. These oxide films were transported with the melt and used as nucleation sites for gas porosity formation. The influence of melt flow due to filling and oxide film distribution was analyzed using a simple 3-block test geometry. The test geometry was cast in A356 and analyzed by computer tomography to validate the porosity prediction.

  20. Generation Control of ZnO Nanoparticles Using a Coaxial Gas-Flow Pulse Plasma Ar/O2 Plasma

    Directory of Open Access Journals (Sweden)

    Hiroki Shirahata

    2015-01-01

    Full Text Available Generation of ZnO nanoparticles was investigated using a coaxial gas-flow pulse plasma. We studied how zinc atoms, sputtered from a zinc target, reacted with oxygen in a plasma and/or on a substrate to form ZnO nanoparticles when the discharge parameters, such as applied pulse voltage and gas flow rate, were controlled in an O2/Ar plasma. The formation processes were estimated by SEM, TEM, and EDX. We observed many ZnO nanoparticles deposited on Si substrate. The particle yield and size were found to be controlled by changing the experimental parameters. The diameter of the particles was typically 50–200 nm.

  1. Reliability of semiconductor and gas-filled diodes for over-voltage protection exposed to ionizing radiation

    Directory of Open Access Journals (Sweden)

    Stanković Koviljka

    2009-01-01

    Full Text Available The wide-spread use of semiconductor and gas-filled diodes for non-linear over-voltage protection results in a variety of possible working conditions. It is therefore essential to have a thorough insight into their reliability in exploitation environments which imply exposure to ionizing radiation. The aim of this paper is to investigate the influence of irradiation on over-voltage diode characteristics by exposing the diodes to californium-252 combined neutron/gamma radiation field. The irradiation of semiconductor over-voltage diodes causes severe degradation of their protection characteristics. On the other hand, gas-filled over-voltage diodes exhibit a temporal improvement of performance. The results are presented with the accompanying theoretical interpretations of the observed changes in over-voltage diode behaviour, based on the interaction of radiation with materials constituting the diodes.

  2. Study of the 30P(α,p)33S reaction using a gas-filled magnetic spectrograph

    International Nuclear Information System (INIS)

    We have developed a technique using a gas-filled magnetic spectrograph which enables us to study (α,p) transfer reactions of astrophysical interest in inverse kinematics and by means of the time-inverse reactions. We present preliminary experimental results of the reaction 30P(α,p)33S which confirm that the technique permits the study of these kinds of transfer reactions.

  3. An experimental challenge: Unraveling the dependencies of ultrasonic and electrical properties of sandy sediments with pore-filling gas hydrates

    Science.gov (United States)

    Heeschen, Katja; Spangenberg, Erik; Seyberth, Karl; Priegnitz, Mike; Schicks, Judith M.

    2016-04-01

    The accuracy of gas hydrate quantification using seismic or electric measurements fundamentally depends on the knowledge of any factor describing the dependencies of physical properties on gas hydrate saturation. Commonly, these correlations are the result of laboratory measurements on artificially produced gas hydrates of exact saturation. Thus, the production of gas hydrates and accurate determination of gas hydrate concentrations or those of a substitute are a major concern. Here we present data of both, seismic and electric measurements on accurately quantified pore-filling ice as a substitute for natural gas hydrates. The method was validated using selected gas hydrate saturations in the same experimental set-up as well as literature data from glass bead samples [Spangenberg and Kulenkampff, 2006]. The environmental parameters were chosen to fit those of a possible gas hydrate reservoir in the Danube Delta, which is in the focus of models for joint inversions of seismic and electromagnetic data in the SUGAR III project. The small effective pressures present at this site proved to be yet another challenge for the experiments. Using a more powerful pulse generator and a 4 electrode electric measurement, respectively, models for a wide range of gas hydrate saturations between 20 - 90 % vol. could be established. Spangenberg, E. and Kulenkampff, J., Influence of methane hydrate content on electrical sediment properties. Geophysical Research Letters 2006, 33, (24).

  4. Hybrid recoil mass analyzer at IUAC – First results using gas-filled mode and future plans

    Indian Academy of Sciences (India)

    N Madhavan; S Nath; T Varughese; J Gehlot; A Jhingan; P Sugathan; A K Sinha; R Singh; K M Varier; M C Radhakrishna; E Prasad; S Kalkal; G Mohanto; J J Das; Rakesh Kumar; R P Singh; S Muralithar; R K Bhowmik; A Roy; Rajesh Kumar; S K Suman; A Mandal; T S Datta; J Chacko; A Choudhury; U G Naik; A J Malyadri; M Archunan; J Zacharias; S Rao; Mukesh Kumar; P Barua; E T Subramanian; K Rani; B P Ajith Kumar; K S Golda

    2010-08-01

    Hybrid recoil mass analyzer (HYRA) is a unique, dual-mode spectrometer designed to carry out nuclear reaction and structure studies in heavy and medium-mass nuclei using gas-filled and vacuum modes, respectively and has the potential to address newer domains in nuclear physics accessible using high energy, heavy-ion beams from superconducting LINAC accelerator (being commissioned) and ECR-based high current injector system (planned) at IUAC. The first stage of HYRA is operational and initial experiments have been carried out using gas-filled mode for the detection of heavy evaporation residues and heavy quasielastic recoils in the direction of primary beam. Excellent primary beam rejection and transmission efficiency (comparable with other gas-filled separators) have been achieved using a smaller focal plane detection system. There are plans to couple HYRA to other detector arrays such as Indian national gamma array (INGA) and 4 spin spectrometer for ER tagged spectroscopic/spin distribution studies and for focal plane decay measurements.

  5. Observation of reduced beam deflection using smoothed beams in gas-filled hohlraum symmetry experiments at Nova

    International Nuclear Information System (INIS)

    Execution and modeling of drive symmetry experiments in gas-filled hohlraums have been pursued to provide both a better understanding of radiation symmetry in such hohlraums and to verify the accuracy of the design tools which are used to predict target performance for the National Ignition Facility (NIF) [J. Lindl, Phys. Plasmas 2, 3933 (1995)]. In this paper, the results of a series of drive symmetry experiments using gas-filled hohlraums at the Nova laser facility [C. Bibeau et al., Appl. Opt. 31, 5799 (1992)] at Lawrence Livermore National Laboratory are presented. A very important element of these experiments was the use of kineform phase plates (KPP) to smooth the Nova beams. The effect of smoothing the ten Nova beams with KPP phase plates is to remove most of the beam bending which had been observed previously, leaving a residual bending of only 1.5 degree sign , equivalent to a 35 μm pointing offset at the hohlraum wall. The results show that the symmetry variation with pointing of implosions in gas-filled hohlraums is consistent with time integrated modeling. (c) 2000 American Institute of Physics

  6. Adding Some Gas Can Completely Change How an Object in a Liquid-Filled Housing Responds to Vibration

    Science.gov (United States)

    Torczynski, J. R.; O'Hern, T. J.; Clausen, J. R.

    2015-11-01

    Adding a little gas can completely change the motion of an object in a liquid-filled housing during vibration. A common system exhibiting this behavior is a spring-supported piston in a liquid-filled cylinder, where the gaps between them are narrow and depend on the piston position. When gas is absent, the piston's vibrational response is highly overdamped due to forcing viscous liquid through narrow gaps. When a small amount of gas is added, Bjerknes forces cause some of the gas to migrate below the piston. The resulting two gas regions form a pneumatic spring that enables the liquid to move with the piston, with the result that very little liquid is forced through the narrow gaps. This ``Couette mode'' has low damping and thus has a strong resonance near the frequency given by the pneumatic spring constant and the piston mass. At this frequency, the piston response is large, and the nonlinearity from the gap geometry produces a net force on the piston. This ``rectified'' force can be many times the piston's weight and can cause the piston to compress its supporting spring. 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 National Nuclear Security Administration under contract DE-AC04-94AL85000.

  7. Characteristics and interpretation of fracture-filled gas hydrate: an example from the Ulleung Basin, East Sea of Korea

    Science.gov (United States)

    Lee, Myung Woong; Collett, Timothy S.

    2013-01-01

    Through the use of 2-D and 3-D seismic data, a total of thirteen sites were selected and drilled in the East Sea of Korea in 2010. A suite of logging-while-drilling (LWD) logs was acquired at each site. LWD logs from the UBGH2-3A well indicate significant gas hydrate in clay-bearing sediments including several zones with massive gas hydrate with a bulk density less than 1.0 g/m3 for depths between 5 and 103 m below the sea floor. The UBGH2-3A well was drilled on a seismically identified chimney structure with a mound feature at the sea floor. Average gas hydrate saturations estimated from the isotropic analysis of ring resistivity and P-wave velocity logs are 80 ± 13% and 47 ± 16%, respectively, whereas they are 46 ± 17% and 45 ± 16%, respectively from the anisotropic analysis. Modeling indicates that the upper part of chimney (between 5 and 45 m below sea floor [mbsf]) is characterized by gas hydrate filling near horizontal fractures (7° dip) and the lower part of chimney (between 45 and 103 mbsf) is characterized by gas hydrate filling high angle fractures on the basis of ring resistivity and P-wave velocity. The anisotropic analysis using P40H resistivity (phase shift resistivity at 32 mHz with 40 inch spacing) and the P-wave velocity yields a gas hydrate saturation of 46 ± 15% and 46 ± 15% respectively, similar to those estimated using ring resistivity and P-wave velocity, but with quite different fracture dip angles. Differences in vertical resolution, depth of investigation, and a finite fracture dimension relative to the tool separation appear to contribute to this discrepancy. Forward modeling of anisotropic resistivity and velocity are essential to identify gas hydrate in fractures and to estimate accurate gas hydrate amounts.

  8. High-power gas-discharge excimer ArF, KrCl, KrF and XeCl lasers utilising two-component gas mixtures without a buffer gas

    Science.gov (United States)

    Razhev, A. M.; Kargapol'tsev, E. S.; Churkin, D. S.

    2016-03-01

    Results of an experimental study of the influence of a gas mixture (laser active medium) composition on an output energy and total efficiency of gas-discharge excimer lasers on ArF* (193 nm), KrCl* (222 nm), KrF* (248 nm) and XeCl* (308 nm) molecules operating without a buffer gas are presented. The optimal ratios of gas components (from the viewpoint of a maximum output energy) of an active medium are found, which provide an efficient operation of laser sources. It is experimentally confirmed that for gas-discharge excimer lasers on halogenides of inert gases the presence of a buffer gas in an active medium is not a necessary condition for efficient operation. For the first time, in two-component gas mixtures of repetitively pulsed gas-discharge excimer lasers on electron transitions of excimer molecules ArF*, KrCl*, KrF* and XeCl*, the pulsed energy of laser radiation obtained under pumping by a transverse volume electric discharge in a low-pressure gas mixture without a buffer gas reached up to 170 mJ and a high pulsed output power (of up to 24 MW) was obtained at a FWHM duration of the KrF-laser pulse of 7 ns. The maximal total efficiency obtained in the experiment with two-component gas mixtures of KrF and XeCl lasers was 0.8%.

  9. Efficient spectral broadening in the 100-W average power regime using gas-filled kagome HC-PCF and pulse compression.

    Science.gov (United States)

    Emaury, Florian; Saraceno, Clara J; Debord, Benoit; Ghosh, Debashri; Diebold, Andreas; Gèrôme, Frederic; Südmeyer, Thomas; Benabid, Fetah; Keller, Ursula

    2014-12-15

    We present nonlinear pulse compression of a high-power SESAM-modelocked thin-disk laser (TDL) using an Ar-filled hypocycloid-core kagome hollow-core photonic crystal fiber (HC-PCF). The output of the modelocked Yb:YAG TDL with 127 W average power, a pulse repetition rate of 7 MHz, and a pulse duration of 740 fs was spectrally broadened 16-fold while propagating in a kagome HC-PCF containing 13 bar of static argon gas. Subsequent compression tests performed using 8.4% of the full available power resulted in a pulse duration as short as 88 fs using the spectrally broadened output from the fiber. Compressing the full transmitted power through the fiber (118 W) could lead to a compressed output of >100  W of average power and >100  MW of peak power with an average power compression efficiency of 88%. This simple laser system with only one ultrafast laser oscillator and a simple single-pass fiber pulse compressor, generating both high peak power >100  MW and sub-100-fs pulses at megahertz repetition rate, is very interesting for many applications such as high harmonic generation and attosecond science with improved signal-to-noise performance. PMID:25503011

  10. The gas holdup in a multiphase reciprocating plate column filled with carboxymethylcellulose solutions

    Directory of Open Access Journals (Sweden)

    I. S. STAMENKOVIC

    2005-12-01

    Full Text Available Gas holdup was investigated in a gas–liquid and gas–liquid-solid reciprocating plate column (RPC under various operation conditions. Aqueous carboxymethylcellulose (sodium salt, CMC solutions were used as the liquid phase, the solid phase was spheres placed into interplate spaces, and the gas plase was air. The gas holdup in the RPC was influenced by: the vibration intensity, i.e., the power consumption, the superficial gas velocity, the solids content and the rheological properties of the liquid phase. The gas holdup increased with increasing vibration intensity and superficial gas velocity in both the two- and three-phase system. With increasing concentration of the CMC PP 50 solution (Newtonian fluid, the gas holdup decreased, because the coalescence of the bubbles was favored by the higher liquid viscosity. In the case of the CMC PP 200 solutions (non-Newtonian liquids, the gas holdup depends on the combined influence of the rheological properties of the liquid phase, the vibration intensity and the superficial gas velocity. The gas holdup in the three-phase systems was greater than that in the two-phase ones under the same operating conditions. Increasing the solids content has little influence on the gas holdup. The gas holdup was correlated with the power consumption (either the time-averaged or total power consuption and the superficial gas velocity.

  11. Electron temperature and density measurement of tungsten inert gas arcs with Ar-He shielding gas mixture

    International Nuclear Information System (INIS)

    The diagnostics of atmospheric welding plasma is a well-established technology. In most cases the measurements are limited to processes using pure shielding gas. However in many applications shielding gas is a mixture of various components including metal vapor in gas metal arc welding (GMAW). Shielding gas mixtures are intentionally used for tungsten inert gas (TIG) welding in order to improve the welding performance. For example adding Helium to Argon shielding gas allows the weld geometry and porosity to be influenced. Yet thermal plasmas produced with gas mixtures or metal vapor still require further experimental investigation. In this work coherent Thomson scattering is used to measure electron temperature and density in these plasmas, since this technique allows independent measurements of electron and ion temperature. Here thermal plasmas generated by a TIG process with 50% Argon and 50% Helium shielding gas mixture have been investigated. Electron temperature and density measured by coherent Thomson scattering have been compared to the results of spectroscopic measurements of the plasma density using Stark broadening of the 696.5 nm Argon spectral line. Further investigations of MIG processes using Thomson scattering technique are planned

  12. The gas holdup in a multiphase reciprocating plate column filled with carboxymethylcellulose solutions

    OpenAIRE

    I. S. STAMENKOVIC; OLIVERA S. STAMENKOVIC; IVANA B. BANKOVIC-ILIC; M. L. LAZIC; V. B. VELJKOVIC; D. U. SKALA

    2005-01-01

    Gas holdup was investigated in a gas–liquid and gas–liquid-solid reciprocating plate column (RPC) under various operation conditions. Aqueous carboxymethylcellulose (sodium salt, CMC) solutions were used as the liquid phase, the solid phase was spheres placed into interplate spaces, and the gas plase was air. The gas holdup in the RPC was influenced by: the vibration intensity, i.e., the power consumption, the superficial gas velocity, the solids content and the rheological properties of the ...

  13. Annual and transient signatures of gas exchange and transport in the Castañar de Ibor cave (Spain

    Directory of Open Access Journals (Sweden)

    Fernandez-Cortes A.

    2009-07-01

    Full Text Available The large microclimatic stability is a basic characteristic of the subterranean karst systems and causes a high sensitivity to changesin environmental conditions. High-accuracy monitoring of Castañar de Ibor cave (Spain determined the temporal evolution of theaerodynamic processes and ventilation rate by tracking CO2 and 222Rn levels over a twelve-month period. This cave is characterizedby a very stable microclimate, with high and relatively constant radon content (the mean value is 32200 Bq/m3, roughly, and thestandard deviation is 7600 Bq/m3 and a moderate and quite stable CO2 concentration (the mean value is 3730 ppm and the standarddeviation is 250 ppm. Beside the general patterns of cave microclimate throughout an annual cycle, some particular microclimaticprocesses are described with regard to the gas exchange between the cave and the outside atmosphere. There is a complexmicroclimatic functional relationship between the meteorological and cave microclimate conditions and the diffusion and flow of tracergases from the fractures and the pore system of soil and host rock to cave atmosphere. Transient variations of tracer gas on cave airare controlled by natural barometric fluxes and anthropogenic forced ventilation due to uncontrolled opening of cave entrance. Theshort-term fluctuations of gas levels on cave air reveal distinct patterns during the exhalation process of theses gases from the netof fissures and pores to the cave atmosphere, depending on the isolation effect of soil and host rock.

  14. Adsorbent filled membranes for gas separation. Part 1. Improvement of the gas separation properties of polymeric membranes by incorporation of microporous adsorbents

    OpenAIRE

    Duval, J.-M.; Folkers, B.; Mulder, M.H.V.; Desgrandchamps, G.; Smolders, C.A.

    1993-01-01

    The effect of the introduction of specific adsorbents on the gas separation properties of polymeric membranes has been studied. For this purpose both carbon molecular sieves and zeolites are considered. The results show that zeolites such as silicate-1, 13X and KY improve to a large extent the separation properties of poorly selective rubbery polymers towards a mixture of carbon dioxide/methane. Some of the filled rubbery polymers achieve intrinsic separation properties comparable to cellulos...

  15. Inductively coupled plasma reactive ion etching of IrMn magnetic thin films using a CH4/O2/Ar gas

    International Nuclear Information System (INIS)

    In this study, the etch characteristics of IrMn magnetic thin films patterned with TiN hard mask were investigated using an inductively coupled plasma reactive ion etching in CH4/Ar and CH4/O2/Ar gas mixes. As the CH4 concentration increased in the CH4/Ar gas, the etch rates of IrMn and TiN films simultaneously decreased, while the etch selectivity increased and etch profiles improved without any redeposition. The addition of O2 to the CH4/Ar gas led to an increase in the etch selectivity and a higher degree of anisotropy in etch profile. The dc-bias voltage and gas pressure were varied to examine and optimize the etching process of IrMn films. Low gas pressure and high dc-bias voltage improved the etch profile, which displayed a high degree of anisotropy. Surface analysis of etched films by X-ray photoelectron spectroscopy was performed to identify the existence of compounds during etching.

  16. Origins of the residual pulse height deficit in propane-filled gas ionization detectors

    International Nuclear Information System (INIS)

    This work investigates the origins of the residual pulse height deficit in gas ionization detectors. It is motivated by the recent observation that the species dependence of gas detector response cannot be accounted for solely by considering the energy loss of the ions in the detector window and non-ionizing energy loss processes in the detector gas. It was found that the residual pulse height deficit is approximately proportional to the square of the ionization density. However, only a weak dependence of the residual deficit on gas pressure (in the range 70-120mbar) was observed. It is hypothesized that the residual pulse height deficit in gas ionization detectors results from the effect of multiple ionization of individual gas molecules at high ionization densities on the energy required to create an electron-ion pair

  17. Picosecond pulses compression at 1053-nm center wavelength by using a gas-filled hollow-core fiber compressor

    International Nuclear Information System (INIS)

    We theoretically study the nonlinear compression of picosecond pulses with 10-mJ of input energy at the 1053-nm center wavelength by using a one-meter-long gas-filled hollow-core fiber (HCF) compressor and considering the third-order dispersion (TOD) effect. It is found that when the input pulse is about 1 ps/10 mJ, it can be compressed down to less than 20 fs with a high transmission efficiency. The gas for optimal compression is krypton gas which is filled in a HCF with a 400-μm inner diameter. When the input pulse duration is increased to 5 ps, it can also be compressed down to less than 100 fs efficiently under proper conditions. The results show that the TOD effect has little impact on picosecond pulse compression and the HCF compressor can be applied on compressing picosecond pulses efficiently with a high compression ratio, which will benefit the research of high-field laser physics. (paper)

  18. Resonant third harmonic generation of KrF laser in Ar gas.

    Science.gov (United States)

    Rakowski, R; Barna, A; Suta, T; Bohus, J; Földes, I B; Szatmári, S; Mikołajczyk, J; Bartnik, A; Fiedorowicz, H; Verona, C; Verona Rinati, G; Margarone, D; Nowak, T; Rosiński, M; Ryć, L

    2014-12-01

    Investigations of emission of harmonics from argon gas jet irradiated by 700 fs, 5 mJ pulses from a KrF laser are presented. Harmonics conversion was optimized by varying the experimental geometry and the nozzle size. For the collection of the harmonic radiation silicon and solar-blind diamond semiconductor detectors equipped with charge preamplifiers were applied. The possibility of using a single-crystal CVD diamond detector for separate measurement of the 3rd harmonic in the presence of a strong pumping radiation was explored. Our experiments show that the earlier suggested 0.7% conversion efficiency can really be obtained, but only in the case when phase matching is optimized with an elongated gas target length corresponding to the length of coherence. PMID:25554270

  19. Effect of Cl2/Ar gas mixing ratio on (Pb,Sr)TiO3 thin film etching behavior in inductively coupled plasma

    International Nuclear Information System (INIS)

    The development of anisotropic etching process for (Pb,Sr)TiO3 (PST) thin films is an important task to provide a small feature size and an accurate pattern transfer. Etching characteristics of PST thin films were investigated using inductively coupled plasma etching system as functions of Cl2/Ar gas mixing ratio. The PST etch rate increased with the increase of chlorine radical and ion energy intensity. It was found that the increasing of Ar content in gas mixture lead to sufficient increasing of etch rate. The maximum etch rate of PST film is 56.2 nm/min at Cl2/(Cl2+Ar) of 0.2. It was proposed that the sputter etching is a dominant etching mechanism while the contribution of chemical reaction is relatively low due to low volatility of etching products

  20. First results from the nuclear astrophysics AMS program at the NSL using the MANTIS system in gas-filled mode

    International Nuclear Information System (INIS)

    The Magnet for Astrophysical Nucleosynthesis studies Through Isobar Separation (MANTIS) system is the new Accelerator Mass Spectrometry (AMS) set-up created during recent upgrades of the Browne-Buechner spectrograph at the University of Notre Dame. Commissioning measurements performed on the separation of 58Fe-58Ni isobars at 114 MeV out of the FN tandem accelerator have shown clear separation, opening the door for a number of future measurements in nuclear astrophysics. The separation of mass-58 isobars has made this system the first in the world to utilise a Browne-Buechner spectrograph in gas-filled mode for AMS measurements with a special focus on nuclear astrophysics

  1. Nuclear charge and isobar separation in a gas-filled enge split-pole magnetic spectrograph

    International Nuclear Information System (INIS)

    The sepration technique is based on the fact that charge-changing processes of an ion in a gas, if they occur frequently enough in a magnetic field region, lead to trajectories determined by the average charge state of the ion in the gas. The technique has been used to separate isobaric 58Ni and 58Fe ions. 7 refs., 4 figs., 1 tab

  2. The gas amplification factor in Kr + iso-pentane filled proportional counters

    International Nuclear Information System (INIS)

    Measurements of gas amplification in a proportional counters with Kr/iso-pentane mixture were performed at pressures ranging from 160 to 970 hPa. A new formula for gas amplification in a proportional counters was derived. A good agreement between the formula and experimental data was found over the range of variables studied. 16 refs., 4 figs., 1 tab. (author)

  3. The Lampedusa supersite of ChArMex: observing aerosol-radiation interactions and gas phase chemistry in the Mediterranean

    Science.gov (United States)

    Formenti, Paola; di Sarra, Alcide Giorgio

    2014-05-01

    Within the frame of the ADRIMED (Aerosol Direct Radiative Impact in the regional climate in the MEDiterranean region) project of the Chemistry-Aerosol Mediterranean experiment (ChArMex), the ENEA Laboratory for Climate Study "Roberto Sarao" (WMO/GAW/NDACC) on the Island of Lampedusa (35°31'N, 12°37°E) has been augmented to one of the supersites of the first phase of the Special Observing Period 1 by the measurements of the in situ properties of aerosols and trace gases by the of the PortablE Gas and Aerosol Sampling Units (PEGASUS) mobile station. The ground-based measurements have been completed by several coordinated overpasses of the ATR-42 and the F20 of SAFIRE. In this paper we present the first highlights of operations, which took place between June 6 and July 8 2013. Insights on the data provide with an unprecedented characterisation of the physico-chemical and properties aerosols and gas phase chemistry on air masses of various origins (pollution, marine, mineral dust, …..). The effect of aerosols on radiation fields is ascertained by coupling ground-based and aircraft measurements during dedicated overpasses providing with measurements of upwelling and downwelling shortwave and longwave radiation fluxes together with the properties of the aerosol load resolved on the column. Coordination with CALIPSO overpasses will also be explored.

  4. Ars disyecta Ars disyecta

    Directory of Open Access Journals (Sweden)

    Alejandra Castillo

    2012-07-01

    Full Text Available Bajo la nominación Ars Disyecta se busca exponer el vínculo entre artes visuales, feminismo y metamorfosis. Las prácticas artísticas feministas aquí presentadas se proponen perturbar el espacio metafórico heredado de la diferencia sexual (pensemos, por ejemplo, en las palabras engendramiento, matriz, vida, compenetración o invaginamiento. En este sentido, la nominación Ars disyecta pone en escena un conjunto de prácticas e intervenciones que intentan interrumpir la matriz de la diferencia, desestabilizando lo femenino desde aquellas figuras que se resisten a la lógica de la totalidad y de un tiempo propio. Buscando seguir la huella de un arte disyecto es que interrogaré en este ensayo aquellas autorías feministas que en el arte contemporáneo trafican con las huellas del contagio, la mutación y la alteridad.This article aims to present the relation between visual arts, feminism I and metamorphosis. The feminist artistic practices portrayed in this article attempt to question categories inherited from the metaphor of sexual difference such as engendering, matrix and life. From this perspective, Ars disyecta will establish a set of artistic practices and interventions that intend to interrupt the proper idea of «feminine difference». Following this line of argument, I will discuss in this article a few contemporary feminist works of art that could be defined by words such as contagious, mutation and otherness.

  5. An overview of noble gas (He, Ne, Ar, Xe) contents and isotope signals in terrestrial diamond

    Science.gov (United States)

    Basu, S.; Jones, A. P.; Verchovsky, A. B.; Kelley, S. P.; Stuart, F. M.

    2013-11-01

    The noble gas geochemistry of different types of terrestrial diamond including coated stones, alluvial diamonds, framesites, carbonados and impact diamonds yields a wealth of information on the sources of volatiles responsible for diamond formation. We present an illustrated compilation of published analyses of noble gases in different types of natural diamond. Noble gases in diamond record primary signatures from the mantle indicative of their integrated sources, and, the contribution of different metasomatic agents including subducting fluids and kimberlitic melt sampled during diamond growth. In addition, they show evidence of secondary processes such as resorption. Most data are available for coated stones, which trap abundant volatile-rich microscopic inclusions in their rims. While the coated stones are dominated by Mid-Oceanic-Ridge-Basalt (MORB) type noble gas signatures, the other diamond types contain predominantly crustal and atmospheric components although some mantle gases may be present, the latter indicated in elevated 20Ne/22Ne and/or 129Xe/132Xe ratios relative to atmospheric values. Some alluvial diamonds have very high 3He/4He that may represent the presence of a solar component trapped during their formation, but are just as likely to be the result of cosmogenic 3He implantation during their prolonged residence at the Earth's surface. Oceanic-Island-Basalt (OIB) type noble gases occur in nanometer sized inclusions in metamorphic diamond from Kazakhstan, yet their significance as a fingerprint of mantle processes is not fully understood. Implanted noble gases occur near the outer surfaces of individual crystals, and are generally not a major hindrance for the study of mantle signatures, except for polycrystalline diamond like framesites with small grain size. Some diamonds including the polycrystalline carbonados, are dominated by crustal noble gases with no discernible mantle component evidenced by very low 3He/4He and 20Ne/22Ne ratios, and very

  6. Operation of low-pressure proportional counter filled with argon-based gas mixtures

    International Nuclear Information System (INIS)

    Mixtures of argon with propane, DME (Dimethyl-ether) and isobutane at total pressures P from 2 kPa to 90 kPa were studied in a low-pressure proportional counter. Strong non-uniform electric fields were thus produced at the anode surface (Sa). Deviations from the exponential dependence of gas gain on high voltage above a certain value of gas gain, M0, were observed in all mixtures. The best energy resolution has been obtained at low gas gains, and at gas gains above M0 resolution degrades much faster in ''thin'' mixtures due to avalanche chain formation. The reduced ionization coefficient α/P under non-equilibrium conditions is a function of mixture composition and of gas pressure. Crossings of α/P curves for different mixture compositions at the same total pressure are observed. The statistics of the avalanche size distribution (relative variance f) was determined by measuring the single-electron (SE) spectra. In pure gases and in mixtures with relatively high content of the molecular gas, the value is f 1. The gas gain where f ∝ 1 is roughly equal to the value of M0, showing that both effects are caused by insufficient quenching of the molecular admixture. (orig.)

  7. A computational model of gas bubble evolution in liquid filled straight tubes

    Science.gov (United States)

    Himm, Jeff; Halpern, David

    1996-11-01

    Deep sea divers suffer from decompression sickness (DCS) when their rate of ascent to the surface is too quick. When the ambient pressure drops, inert gas bubbles are usually formed in blood vessels and tissues of divers. It is believed that the existence of gas bubbles is the cause of DCS that manifests itself as itching, joint pain, and neurological abnormalities. While models of gas bubbles in tissues are relatively well developed, the mechanism of bubble growth in the circulation is far less well understood. The existence of gas bubbles may affect gas exchange in small blood vessels by blocking the flow of blood. Gas bubble evolution in the circulation is investigated using an analytical method for small bubbles and the boundary element method for bubbles whose effective radius is close to the tube radius. The concentration field for the dissolved gas surrounding the bubble is solved numerically using finite differences. The bubble volume is adjusted over time according to the mass flux at the surface. It is shown that the effect of increasing the flow rate is to enhance bubble evolution, up to a factor of two compared with the evolution in tissue where there is no flow. This work was supported by the Naval Medical Research and Development Command work unit 62233N.MM33P30.0041509.

  8. Niobium films produced by magnetron sputtering using an Ar-He mixture as discharge gas

    CERN Document Server

    Schucan, G M; Calatroni, Sergio

    1995-01-01

    Superconducting RF accelerating cavities have been produced at CERN by sputter-coating, with a thin niobium layer, cavities made of copper. In the present work, the discharge behaviour and niobium film properties have been investigated when part of the argon sputtering gas is replaced with helium. Helium is chosen because of its low mass, which reduces the energy lost by the niobium atoms colliding with the sputter gas atoms. The higher niobium atom energy should lead to higher adatom mobility on the substrate and, hence, to a larger grain size, a feature which is highly desirable to reduce the cavity surface resistance. It has been found that helium addition effectively helps to maintain the discharge at considerably lower argon pressures, via metastable-neutral ionisation and high secondary electron yield. However, a large amount of helium is trapped in the film, amount which is proportional to the helium partial pressure during the discharge, resulting in a reduction of both Residual Resistivity Ratio and ...

  9. Surface modification of graphite-encapsulated iron nanoparticles by RF excited Ar/NH3 gas mixture plasma and their application to Escherichia coli capture

    Science.gov (United States)

    Viswan, Anchu; Chou, Han; Sugiura, Kuniaki; Nagatsu, Masaaki

    2016-09-01

    Graphite-encapsulated iron nanoparticles with an average diameter of 20 nm were synthesized using the DC arc discharge method. For biomedical application, the nanoparticles were functionalized with amino groups using an inductively coupled radio-frequency (RF) plasma. The Ar, NH3, and Ar/NH3 plasmas that were used for functionalization were diagnosed using optical emission spectroscopy, confirming the presence of the required elements. The best conditions for functionalization were optimized by changing various parameters. The pretreatment time with Ar plasma was varied from 0 to 12.5 min, the post-treatment time from 30 s to 3 min. The dependence of the RF power and the gas mixture ratio of Ar/NH3 on the amino group population was also analyzed. From Raman spectroscopy, x-ray photoelectron spectroscopy, and determination of absolute number of amino groups through chemical derivatization, it was found that 5 min of Ar pretreatment and 6%NH3/94%Ar plasma post-treatment for 3 min with an RF power of 80 W gives the best result of about 5  ×  104 amino groups per particle. The nanoparticles that were amino functionalized under optimized conditions and immobilized with an Escherichia coli (E.coli) antibody on their surface were incubated with E.coli bacteria to determine the efficiency of collection by direct culture assay.

  10. Sustenance of a gas-filled ΔE-counter at subatmospheric pressures for more than 150 days

    International Nuclear Information System (INIS)

    The long-term sustenance of the performance of a metal body ΔE-gas counter filled to subatmospheric pressures is extended from our previous study. This has been possible by introducing within the counter volume an iron-oxide based catalyst that can efficiently reduce the presence of electronegative impurities. By this means the gas counter can be continuously operated for more than five months with minimal peak channel shift and good resolution. Initially the counter was kept in the atmospheric environment which led to a slow decrease in peak channel, but subsequently when it was operated in vacuum environment the peak channel starts to appreciate and ultimately saturates at the initial value. The resolution (%) also remains steady around 11-13%. Various other factors determining the counter performance viz., efficiency, shape of the peak etc., are also studied. The experiment is carried out both for stainless steel and aluminum body counters. (orig.)

  11. Strong Raman-induced noninstantaneous soliton interactions in gas-filled photonic crystal fibers.

    Science.gov (United States)

    Saleh, Mohammed F; Armaroli, Andrea; Marini, Andrea; Biancalana, Fabio

    2015-09-01

    We have developed an analytical model based on the perturbation theory to study the optical propagation of two successive solitons in hollow-core photonic crystal fibers filled with Raman-active gases. Based on the time delay between the two solitons, we have found that the trailing soliton dynamics can experience unusual nonlinear phenomena, such as spectral and temporal soliton oscillations and transport toward the leading soliton. The overall dynamics can lead to a spatiotemporal modulation of the refractive index with a uniform temporal period and a uniform or chirped spatial period. PMID:26368711

  12. Strong Raman-induced non-instantaneous soliton interactions in gas-filled photonic crystal fibers

    CERN Document Server

    Saleh, Mohammed F; Marini, Andrea; Biancalana, Fabio

    2015-01-01

    We have developed an analytical model based on the perturbation theory in order to study the optical propagation of two successive intense solitons in hollow-core photonic crystal fibers filled with Raman-active gases. Based on the time delay between the two solitons, we have found that the trailing soliton dynamics can experience unusual nonlinear phenomena such as spectral and temporal soliton oscillations and transport towards the leading soliton. The overall dynamics can lead to a spatiotemporal modulation of the refractive index with a uniform temporal period and a uniform or chirped spatial period.

  13. Optical design and characterization of a gas filled MEMS Fabry-Perot filter

    Science.gov (United States)

    Ayerden, N. Pelin; Ghaderi, Mohammadamir; de Graaf, Ger; Wolffenbuttel, Reinoud F.

    2015-05-01

    A concept for a highly integrated and miniaturized gas sensor based on infrared absorption, a Fabry-Perot type linear variable optical filter with integrated gas cell, is presented. The sample chamber takes up most of the space in a conventional spectrometer and is the only component that has so far not been miniaturized. In this concept the gas cell is combined with the resonator cavity of the filter. The optical design, fabrication, and characterization results on a MEMSbased realization are reported for a 24-25.5 μm long tapered resonator cavity. Multiple reflections from highly reflective mirrors enable this optical cavity to also act as a gas cell with an equivalent optical absorption path length of 8 mm. Wideband operation of the filter is ensured by fabrication of a tapered mirror. In addition to the functional integration and significant size reduction, the filter contains no moving parts, thus enables the fabrication of a robust microspectrometer

  14. Smoothing single-crystalline SiC surfaces by reactive ion etching using pure NF3 and NF3/Ar mixture gas plasmas

    International Nuclear Information System (INIS)

    In pure NF3 plasma, the etching rates of four kinds of single-crystalline SiC wafer etched at NF3 pressure of 2 Pa were the highest and it decreased with an increase in NF3 pressure. On the other hand, they increased with an increase in radio frequency (RF) power and were the highest at RF power of 200 W. A smooth surface was obtained on the single-crystalline 4H-SiC after reactive ion etching at NF3/Ar gas pressure of 2 Pa and addition of Ar to NF3 plasma increased the smoothness of SiC surface. Scanning electron microscopy observation revealed that the number of pillars decreased with an increase in the Ar-concentration in the NF3/Ar mixture gas. The roughness factor (Ra) values were decreased from 51.5 nm to 25.5 nm for the As-cut SiC, from 0.25 nm to 0.20 nm for the Epi-SiC, from 5.0 nm to 0.7 nm for the Si-face mirror-polished SiC, and from 0.20 nm to 0.16 nm for the C-face mirror-polished SiC by adding 60% Ar to the NF3 gas. Both the Ra values of the Epi- and the C-face mirror-polished wafer surfaces etched using the NF3/Ar (40:60) plasma were similar to that treated with mirror polishing, so-called the Catalyst-Referred Etching (CARE) method, with which the lowest roughness of surface was obtained among the chemical mirror polishing methods. Etching duration for smoothing the single-crystalline SiC surface using its treatment was one third of that with the CARE method

  15. Heat and mass transfer across gas-filled enclosed spaces between a hot liquid surface and a cooled roof

    International Nuclear Information System (INIS)

    A detailed knowledge is required of the amounts of sodium vapour which may be transported from the hot surface of a fast reactor coolant pool through the cover gas to cooler regions of the structure. Evaporation from the unbounded liquid surfaces of lakes and seas has been studied extensively but the heat and mass transfer mechanisms in gas-vapour mixtures which occur in enclosed spaces have received less attention. Recent work at Harwell has provided a theoretical model from which the heat and mass transfer in idealised plane cavities can be calculated. An experimental study is reported in this paper which seeks to verify the theoretical prediction. Heat and mass transfer measurements have been made on a system in which a heated water pool transfers heat and mass across a gas-filled space to a cooled horizontal cover plate. Several cover gases were used in the experiments and the results show that, provided the partial density of the vapour is low compared with that of the gas, the heat transfer mechanism is that of combined convection and radiation. The enhancement in heat transfer due to the presence of the vapour is broadly consistent with assumption of a direct analogy between heat and mass transfer neglecting condensation in the interspace. The mass transfer measurements, in which water condensing on the cooled roof was measured directly, showed for low roof temperatures an imbalance between the mass and heat transfer. This observation is consistent with the theoretical predictions that heat transfer in the convecting system should be independent of the amount of condensation and 'rain-back' within the cavity. The results of tests with helium showed that convection was entirely suppressed by the presence of the water vapour. This confirms the behaviour predicted for gas-vapour mixtures in which the vapour density is of the same order as the gas density. (author)

  16. Study of x-rays produced from debris-free sources with Ar, Kr and Kr/Ar mixture linear gas jets irradiated by UNR Leopard laser beam with fs and ns pulse duration

    Science.gov (United States)

    Kantsyrev, V. L.; Schultz, K. A.; Shlyaptseva, V. V.; Safronova, A. S.; Shrestha, I. K.; Petrov, G. M.; Moschella, J. J.; Petkov, E. E.; Stafford, A.; Cooper, M. C.; Weller, M. E.; Cline, W.; Wiewior, P.; Chalyy, O.

    2016-06-01

    Experiments of x-ray emission from Ar, Kr, and Ar/Kr gas jet mixture were performed at the UNR Leopard Laser Facility operated with 350 fs pulses at laser intensity of 2 × 1019 W/cm2 and 0.8 ns pulses at an intensity of 1016 W/cm2. Debris free x-ray source with supersonic linear nozzle generated clusters/monomer jet with an average density of ≥1019 cm-3 was compared to cylindrical tube subsonic nozzle, which produced only monomer jet with average density 1.5-2 times higher. The linear (elongated) cluster/gas jet provides the capability to study x-ray yield anisotropy and laser beam self-focusing with plasma channel formation that are interconnecting with efficient x-ray generation. Diagnostics include x-ray diodes, pinhole cameras and spectrometers. It was observed that the emission in the 1-9 keV spectral region was strongly anisotropic depending on the directions of laser beam polarization for sub-ps laser pulse and supersonic linear jet. The energy yield in the 1-3 keV region produced by a linear nozzle was an order of magnitude higher than from a tube nozzle. Non-LTE models and 3D molecular dynamic simulations of Ar and Kr clusters irradiated by sub-ps laser pulses have been implemented to analyze obtained data. A potential evidence of electron beam generation in jets' plasma was discussed. Note that the described debris-free gas-puff x-ray source can generate x-ray pulses in a high repetition regime. This is a great advantage compared to solid laser targets.

  17. Noble Gas Inserted Protonated Silicon Monoxide Cations: HNgOSi(+) (Ng = He, Ne, Ar, Kr, and Xe).

    Science.gov (United States)

    Sekhar, Pooja; Ghosh, Ayan; Ghanty, Tapan K

    2015-11-25

    The existence of noble gas containing protonated silicon monoxide complexes have been predicted theoretically through ab initio quantum chemical methods. The predicted HNgOSi(+) ions are obtained by insertion of a noble gas atom (Ng = He, Ne, Ar, Kr, and Xe) between the H and O atoms in SiOH(+) ion. The structural parameters, energetics, harmonic vibrational frequencies, and charge distributions have been analyzed by optimizing the minima and the transition state structures using second-order Møller-Plesset perturbation theory (MP2), density functional theory (DFT), and coupled-cluster theory (CCSD(T)) based techniques. The predicted HNgOSi(+) ions are found to be stable with respect to all possible 2-body and 3-body dissociation channels, except the dissociation path leading to the respective global minimum products. However, these ions are found to be kinetically stable with respect to the global minimum dissociation process as revealed from the finite barrier heights, which in turn can prevent the transformation of these metastable species to the global minimum products. Furthermore, the computed bond lengths, vibrational frequencies, and force constant values suggest that a strong covalent bond exists between the H and Ng atoms in HNgOSi(+) ions while the Ng and O atoms share a strong van der Waals kind of interaction. Charge distributions and bonding analysis indicate that HNgOSi(+) ions can be best represented as strong complexes between the [HNg](+) ions and OSi molecule. All the computational results suggest that the predicted species, HNgOSi(+), may be prepared and characterized by suitable experimental technique at cryogenic temperature. PMID:26501440

  18. Noble-Gas-Inserted Fluoro(sulphido)boron (FNgBS, Ng = Ar, Kr, and Xe): A Theoretical Prediction.

    Science.gov (United States)

    Ghosh, Ayan; Dey, Sourav; Manna, Debashree; Ghanty, Tapan K

    2015-06-01

    The possibility of the existence of a new series of neutral noble gas compound, FNgBS (where Ng = Ar, Kr, Xe), is explored theoretically through the insertion of a Ng atom into the fluoroborosulfide molecule (FBS). Second-order Møller-Plesset perturbation theory, density functional theory, and coupled cluster theory based methods have been employed to predict the structure, stability, harmonic vibrational frequencies, and charge distribution of FNgBS molecules. Through energetics study, it has been found that the molecules could dissociate into global minima products (Ng + FBS) on the respective singlet potential energy surface via a unimolecular dissociation channel; however, the sufficiently large activation energy barriers provide enough kinetic stability to the predicted molecules, which, in turn, prevent them from dissociating into the global minima products. Moreover, the FNgBS species are thermodynamically stable, owing to very high positive energies with respect to other two two-body dissociation channels, leading to FNg + BS and F(-) + NgBS(+), and two three-body dissociation channels, corresponding to the dissociation into F + Ng + BS and F(-) + Ng + BS(+). Furthermore, the Mulliken and NBO charge analysis together with the AIM results reveal that the Ng-B bond is more of covalent in nature, whereas the F-Ng bond is predominantly ionic in character. Thus, these compounds can be better represented as F(-)[NgBS](+). This fact is also supported by the detail analysis of bond length, bond dissociation energy, and stretching force constant values. All of the calculated results reported in this work clearly indicate that it might be possible to prepare and characterize the FNgBS molecules in cryogenic environment through matrix isolation technique by using a mixture of OCS/BF3 in the presence of large quantity of noble gas under suitable experimental conditions. PMID:25928588

  19. Fabrication and testing of gas filled targets for large scale plasma experiments on Nova

    International Nuclear Information System (INIS)

    An experimental campaign on the Nova laser was started in July 1993 to study one st of target conditions for the point design of the National Ignition Facility (NIF). The targets were specified to investigate the current NIF target conditions--a plasma of ∼3 keV electron temperature and an electron density of ∼1.0 E + 21 cm-3. A gas cell target design was chosen to confine as gas of ∼0.01 cm3 in volume at ∼ 1 atmosphere. This paper will describe the major steps and processes necessary in the fabrication, testing and delivery of these targets for shots on the Nova Laser at LLNL

  20. Fabrication and testing of gas filled targets for large scale plasma experiments on Nova

    Energy Technology Data Exchange (ETDEWEB)

    Stone, G.F.; Spragge, M.; Wallace, R.J. [Lawrence Livermore National Lab., CA (United States); Rivers, C.J. [Lawrence Livermore National Lab., CA (United States)]|[Schafer (W.J.) Associates, Inc., Livermore, CA (United States)

    1995-03-06

    An experimental campaign on the Nova laser was started in July 1993 to study one st of target conditions for the point design of the National Ignition Facility (NIF). The targets were specified to investigate the current NIF target conditions--a plasma of {approximately}3 keV electron temperature and an electron density of {approximately}1.0 E + 21 cm{sup {minus}3}. A gas cell target design was chosen to confine as gas of {approximately}0.01 cm{sup 3} in volume at {approximately} 1 atmosphere. This paper will describe the major steps and processes necessary in the fabrication, testing and delivery of these targets for shots on the Nova Laser at LLNL.

  1. Fabrication and testing of gas-filled targets for large-scale plasma experiments on nova

    Energy Technology Data Exchange (ETDEWEB)

    Stone, G.F.; Rivers, C.J.; Spragge, M.R.; Wallace, R.J.

    1996-06-01

    The proposed next-generation ICF facility, the National Ignition Facility (NIF) is designed to produce energy gain from x-ray heated {open_quotes}indirect-drive{close_quotes} fuel capsules. For indirect-drive targets, laser light heats the inside of the Au hohlraum wall and produces x rays which in turn heat and implode the capsule to produce fusion conditions in the fuel. Unlike Nova targets, in NIF-scale targets laser light will propagate through several millimeters of gas, producing a plasma, before impinging upon the Au hohlraum wall. The purpose of the gas-produced plasma is to provide sufficient pressure to keep the radiating Au surface from expanding excessively into the hohlraum cavity. Excessive expansion of the Au wall interacts with the laser pulse and degrades the drive symmetry of the capsule implosion. The authors have begun an experimental campaign on the Nova laser to study the effect of hohlraum gas on both laser-plasma interaction and implosion symmetry. In their current NIF target design, the calculated plasma electron temperature is T{sub e} {approx} 3 keV and the electron density is N{sub e} {approx} 10{sup 21}cm{sup {minus}3}.

  2. Synchrotron X-Ray Study of Melting in Submonolayer Ar and other Rare-Gas Films on Graphite

    DEFF Research Database (Denmark)

    McTague, J. P.; Als-Nielsen, Jens Aage; Bohr, Jakob;

    1982-01-01

    Synchrotron x-ray diffraction studies of the (10) peak of Ar on the (001) surface of ZYX graphite show a sharp but continuous broadening of the Bragg peak with increasing temperature. Below a coverage of ∼ 1 Ar atom per six surface carbon atoms (ρ=1) the onset of this transition occurs at a...

  3. Absolute CF2 density and gas temperature measurements by absorption spectroscopy in dual-frequency capacitively coupled CF4/Ar plasmas

    International Nuclear Information System (INIS)

    Broadband ultraviolet absorption spectroscopy has been used to determine the CF2 radical density in dual-frequency capacitively coupled CF4/Ar plasmas, using the CF2 A~1B1←X~1A1 system of absorption spectrum. The rotational temperature of ground state CF2 and excited state CF was also estimated by using A~1B1←X~1A1 system and B2Δ−X2Π system, respectively. The translational gas temperature was deduced from the Doppler width of the Ar*(3P2) and Ar*(3P0) metastable atoms absorption line by using the tunable diode laser absorption spectroscopy. The rotational temperatures of the excited state CF are about 100 K higher than those of ground state CF2, and about 200 K higher than the translational gas temperatures. The dependences of the radical CF2 density, electron density, electron temperature, rotational temperature, and gas temperature on the high frequency power and pressure have been analyzed. Furthermore, the production and loss mechanisms of CF2 radical and the gas heating mechanisms have also been discussed

  4. Accelerator mass spectrometry of 63Ni using a gas-filled magnet at the Munich Tandem Laboratory

    Science.gov (United States)

    Rugel, G.; Faestermann, T.; Knie, K.; Korschinek, G.; Marchetti, A. A.; McAninch, J. E.; Rühm, W.; Straume, T.; Wallner, C.

    2000-10-01

    The detection of 63Ni ( T1/2=100.1 yr) by means of accelerator mass spectrometry (AMS) using a gas-filled magnet (GFM) is described. The experimental setup includes a dedicated ion source, a 14 MV MP tandem, a GFM and a multi-anode ionization chamber. First results indicate a background level of 63Ni/Ni ratios as low as 2×10 -14. This sensitivity will allow - for the first time ever - to detect 63Ni induced by fast neutrons in copper samples from Hiroshima and Nagasaki, even for distances beyond 1500 m from the hypocenters. Thus, it will be possible to reconstruct experimentally the neutron doses of the A-bomb survivors from Hiroshima and Nagasaki.

  5. Accelerator mass spectrometry of 63Ni using a gas-filled magnet at the Munich Tandem Laboratory

    International Nuclear Information System (INIS)

    The detection of 63Ni (T1/2=100.1 yr) by means of accelerator mass spectrometry (AMS) using a gas-filled magnet (GFM) is described. The experimental setup includes a dedicated ion source, a 14 MV MP tandem, a GFM and a multi-anode ionization chamber. First results indicate a background level of 63Ni/Ni ratios as low as 2x10-14. This sensitivity will allow - for the first time ever - to detect 63Ni induced by fast neutrons in copper samples from Hiroshima and Nagasaki, even for distances beyond 1500 m from the hypocenters. Thus, it will be possible to reconstruct experimentally the neutron doses of the A-bomb survivors from Hiroshima and Nagasaki

  6. Effect of a transverse magnetic field on the generation of electron beams in the gas-filled diode

    Science.gov (United States)

    Baksht, E. H.; Burachenko, A. G.; Erofeev, M. V.; Kostyrya, I. D.; Lomaev, M. I.; Rybka, D. V.; Tarasenko, V. F.

    2008-06-01

    The effect of a transverse magnetic field (0.080 and 0.016 T) on generation of an electron beam in the gas-filled diode is experimentally investigated. It is shown that, at voltage U = 25 kV across the diode and a low helium pressure (45 Torr), the transverse magnetic field influences the beam current amplitude behind a foil and its distribution over the foil cross section. At elevated pressures and under the conditions of ultrashort avalanche electron beam formation in helium, nitrogen, and air, the transverse magnetic field (0.080 and 0.016 T) has a minor effect on the amplitude and duration of the beam behind the foil. It is established that, when the voltage of the pulse generator reaches several hundreds of kilovolts, some runaway electrons (including the electrons from the discharge plasma near the cathode) are incident on the side walls of the diode.

  7. Gas filled prototype of a CdZnTe pixel detector

    International Nuclear Information System (INIS)

    CdZnTe pixel structures are currently the most promising detectors for the focal planes of hard X-ray telescopes, for astronomical observation in the range 5-100 keV. In Sharma et al. (Proc. SPIE 3765 (1999) 822) and Ramsey et al. (Nucl. Instrum. Methods A 458 (2001) 55) we presented preliminary results on the development of prototype 4x4 CdZnTe imaging detectors operated under vacuum. These pixel detectors were installed inside vacuum chambers on three-stage Peltier coolers providing detector temperatures down to -40 deg. C. A miniature sputter ion pump inside each chamber maintained the necessary vacuum of 10-5 Torr. At a temperature of -20 deg. C we achieved an FWHM energy resolution of between 2% and 3% at 60 keV and ∼15% at 5.9 keV; however, the dependency on temperature was weak and at +20 deg. C the respective resolutions were 3% and 20%. As the detectors could be operated at room temperature without loss of their good characteristics it was possible to exclude the sputter ion pump and fill the chamber with dry nitrogen instead. We have tested a nitrogen-filled CdZnTe (5x5x1 mm3) prototype having 0.65x0.65 mm2 readout pads on a 0.75 mm pitch. The interpixel resistance at an applied voltage of 10 V was higher than 50 GΩ and the pixel leakage currents at room temperature with a bias of 200 V between each pad and the common electrode did not exceed 0.8 nA. The pixel detector inside the microassembly, which also contained the input stages of the preamplifiers, was installed on a Peltier cooler to maintain the detector temperature at +20 deg. C. To define real leakage currents of the pixels in their switched-on state we have checked the voltage on the preamplifiers feedback resistors. The resulting currents were 10-50 pA at a detector bias of 500 V. Under test, the typical energy resolution per pixel at +20 deg. C was ∼3% at energy 59.6 keV and ∼20% at energy 5.9 keV, which are similar to the values obtained in the vacuum prototype at room temperature

  8. Gas filled prototype of a CdZnTe pixel detector

    Energy Technology Data Exchange (ETDEWEB)

    Ramsey, B.; Sharma, D.; Sipila, H.; Gostilo, V. E-mail: bsi@bsi.lv; Loupilov, A

    2001-06-01

    CdZnTe pixel structures are currently the most promising detectors for the focal planes of hard X-ray telescopes, for astronomical observation in the range 5-100 keV. In Sharma et al. (Proc. SPIE 3765 (1999) 822) and Ramsey et al. (Nucl. Instrum. Methods A 458 (2001) 55) we presented preliminary results on the development of prototype 4x4 CdZnTe imaging detectors operated under vacuum. These pixel detectors were installed inside vacuum chambers on three-stage Peltier coolers providing detector temperatures down to -40 deg. C. A miniature sputter ion pump inside each chamber maintained the necessary vacuum of 10{sup -5} Torr. At a temperature of -20 deg. C we achieved an FWHM energy resolution of between 2% and 3% at 60 keV and {approx}15% at 5.9 keV; however, the dependency on temperature was weak and at +20 deg. C the respective resolutions were 3% and 20%. As the detectors could be operated at room temperature without loss of their good characteristics it was possible to exclude the sputter ion pump and fill the chamber with dry nitrogen instead. We have tested a nitrogen-filled CdZnTe (5x5x1 mm{sup 3}) prototype having 0.65x0.65 mm{sup 2} readout pads on a 0.75 mm pitch. The interpixel resistance at an applied voltage of 10 V was higher than 50 G{omega} and the pixel leakage currents at room temperature with a bias of 200 V between each pad and the common electrode did not exceed 0.8 nA. The pixel detector inside the microassembly, which also contained the input stages of the preamplifiers, was installed on a Peltier cooler to maintain the detector temperature at +20 deg. C. To define real leakage currents of the pixels in their switched-on state we have checked the voltage on the preamplifiers feedback resistors. The resulting currents were 10-50 pA at a detector bias of 500 V. Under test, the typical energy resolution per pixel at +20 deg. C was {approx}3% at energy 59.6 keV and {approx}20% at energy 5.9 keV, which are similar to the values obtained in the

  9. Supernova Feedback and the Hot Gas Filling Fraction of the Interstellar Medium

    CERN Document Server

    Li, Miao; Cen, Renyue; Bryan, Greg L; Naab, Thorsten

    2015-01-01

    Supernovae are the most energetic among stellar feedback processes, and are crucial for regulating the interstellar medium (ISM) and launching galactic winds. We explore how supernova remnants (SNRs) create a multiphase medium by performing high resolution, 3D hydrodynamical simulations at various SN rates, $S$, and ISM average densities, $n$. We find that the evolution of a SNR in a self-consistently generated three-phase ISM is qualitatively different from that in a uniform or a two-phase warm/cold medium. By traveling faster and further in the cooling-inefficient hot phase, the spatial-temporal domain of a SNR is enlarged by $>10^{2.5}$ in a hot-dominated multiphase medium (HDMM) compared to the uniform case. We then examine the resultant ISM as we vary $n$ and $S$, finding that a steady state can only be achieved when the hot gas volume fraction \\fvh $\\lesssim 0.6\\pm 0.1$. Above that, overlapping SNRs render connecting topology of the hot gas, and such a HDMM is subjected to thermal runaway with growing p...

  10. Effect of stratified inequality of blood flow on gas exchange in liquid-filled lungs.

    Science.gov (United States)

    West, J. B.; Maloney, J. E.; Castle, B. L.

    1972-01-01

    This investigation set out to answer two questions: (1) are the distal alveoli in the terminal lung units less well perfused than the proximal alveoli, i.e., is there stratification of blood flow; and (2) if so, does this enhance gas exchange in the presence of stratified inequality of ventilation. Excised dog lungs were ventilated with saline and perfused with blood. Following single inspirations of xenon 133 in saline and various periods of breath holding, the expired xenon concentration against volume was measured and it confirmed marked stratified inequality of ventilation under these conditions. By measuring the rate of depletion of xenon from alveoli during a period of blood flow, we showed that the alveoli which emptied at the end of expiration had 16% less blood flow than those exhaling earlier. However, by measuring the xenon concentration in pulmonary venous blood, we found that about 10% less tracer was transferred from the alveoli into the blood when the inspired xenon was stratified within the respiratory zone. Thus while stratification of blood flow was confirmed, it was shown to impair rather than enhance the efficiency of gas transfer.

  11. Electrical compensation method of mechanically induced disturbances in gas-filled radiation detectors

    International Nuclear Information System (INIS)

    In recent years ionization chambers could be improved in many properties such as accuracy and speed. Rise time values of about 1 ms could be realized by the implementation of high sophisticated inner electrode configurations reducing the free length between the electrodes of about 10 mm distance, so that the slow gas-ions generate a displacement current only over a short time interval. These improvements are combined with the disadvantage of increasing sensitivity to mechanical loads as vibrations and shocks. These effects reduce the good applicability of ionization chambers specially in a rough industrial environment. The solution for this problem can be found by using improved mechanical constructions enclosed damped mounting and stabilized construction elements. This paper describes an electrical compensation method of mechanically induced disturbing signals. The implementation is independent of a special detector and can be applied for the suppression of interference signals caused by the 'microphony' effect, comparable with the known operation of a condenser microphone. (orig.)

  12. Supernova Feedback and the Hot Gas Filling Fraction of the Interstellar Medium

    Science.gov (United States)

    Li, Miao; Ostriker, Jeremiah P.; Cen, Renyue; Bryan, Greg L.; Naab, Thorsten

    2015-11-01

    Supernovae (SNe), the most energetic stellar feedback mechanism, are crucial for regulating the interstellar medium (ISM) and launching galactic winds. We explore how supernova remnants (SNRs) create a multiphase medium by performing three-dimentional hydrodynamical simulations at various SN rates, S, and ISM average densities, \\bar{n}. The evolution of an SNR in a self-consistently generated three-phase ISM is qualitatively different from that in a uniform or a two-phase warm/cold medium. By traveling faster and further in the low-density hot phase, the domain of an SNR increases by >102.5. Varying \\bar{n} and S, we find that a steady state can only be achieved when the hot gas volume fraction {f}{{V,hot}}≲ 0.6+/- 0.1. Above that level, overlapping SNRs render connecting topology of the hot gas, and the ISM is subjected to thermal runaway. Photoelectric heating (PEH) has a surprisingly strong impact on {f}{{V,hot}}. For \\bar{n}≳ 3 {{cm}}-3, a reasonable PEH rate is able to suppress the thermal runaway. Overall, we determine the critical SN rate for the onset of thermal runaway to be {S}{{crit}}=200{(\\bar{n}/1 {{cm}}-3)}k{({E}{{SN}}/{10}51 {{erg}})}-1 {{{kpc}}}-3 {{Myr}}-1, where k = (1.2, 2.7) for \\bar{n}≤slant 1 and \\gt 1 {{cm}}-3, respectively. We present a fitting formula of the ISM pressure P(\\bar{n},S), which can be used as an effective equation of state in cosmological simulations. Despite the five orders of magnitude span of (\\bar{n},S), the average Mach number varies little: {M} ≈ 0.5 ± 0.2, 1.2 ± 0.3, and 2.3 ± 0.9 for the hot, warm, and cold phases, respectively.

  13. Effects of Ar or O2 Gas Bubbling for Shape, Size, and Composition Changes in Silver-Gold Alloy Nanoparticles Prepared from Galvanic Replacement Reaction

    Directory of Open Access Journals (Sweden)

    Md. Jahangir Alam

    2013-01-01

    Full Text Available The galvanic replacement reaction between silver nanostructures and AuCl4- solution has recently been demonstrated as a versatile method for generating metal nanostructures with hollow interiors. Here we describe the results of a systematic study detailing the morphological, structural, compositional, and spectral changes involved in such a heterogeneous reaction on the nanoscale. Effects of Ar or O2 gas bubbling for the formation of Ag-Au alloy nanoparticles by the galvanic replacement between spherical Ag nanoparticles and AuCl4- especially were studied in ethylene glycol (EG at 150°C. The shape, size, and composition changes occur rapidly under O2 bubbling in comparison with those under Ar bubbling. The major product after 60 min heating under Ar gas bubbling was perforated Ag-Au alloy particles formed by the replacement reaction and the minor product was ribbon-type particles produced from splitting off some perforated particles. On the other hand, the major product after 60 min heating under O2 gas bubbling was ribbon-type particles. In addition, small spherical Ag particles are produced. They are formed through rereduction of Ag+ ions released from the replacement reaction and oxidative etching of Ag nanoparticles by O2/Cl− in EG.

  14. Standard practice for examination of seamless, Gas-Filled, pressure vessels using acoustic emission

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This practice provides guidelines for acoustic emission (AE) examinations of seamless pressure vessels (tubes) of the type used for distribution or storage of industrial gases. 1.2 This practice requires pressurization to a level greater than normal use. Pressurization medium may be gas or liquid. 1.3 This practice does not apply to vessels in cryogenic service. 1.4 The AE measurements are used to detect and locate emission sources. Other nondestructive test (NDT) methods must be used to evaluate the significance of AE sources. Procedures for other NDT techniques are beyond the scope of this practice. See Note 1. Note 1—Shear wave, angle beam ultrasonic examination is commonly used to establish circumferential position and dimensions of flaws that produce AE. Time of Flight Diffraction (TOFD), ultrasonic examination is also commonly used for flaw sizing. 1.5 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only. 1.6 This standa...

  15. Analysis of burns caused by pre-filled gas canisters used for lamps or portable camping stoves.

    Science.gov (United States)

    Desouches, C; Salazard, B; Romain, F; Karra, C; Lavie, A; Volpe, C Della; Manelli, J C; Magalon, G

    2006-12-01

    The use of pre-filled valveless gas canisters for lamps or camping stoves has caused a number of serious burn incidents. We performed a retrospective analysis of all of the patients who were victims of such incidents admitted to the Marseille Burn Centre between January 1990 and March 2004. There were a total of 21 patients burned in such conditions. Adult males made up the majority of the victims of this sort. Lesions were often extensive (60% of the patients were burned over more than 10% of their body surface) and systematically deep. In order of frequency, burn locations were: the lower limbs, the upper limbs, the hands and the face. The incidents principally occurred during replacement of the canister near an open flame. The marketing of a canister with a valve in order to avoid gas leaks did not cause the old canisters to be taken off the market. On the contrary, European Safety Standard EN417, updated in October 2003, validated the use of these valveless canisters. The severity of the lesions caused and the existence of safe equivalent products requires the passage of a law that forbids valveless canisters. PMID:16982156

  16. Microcontroller based system for electrical breakdown time delay measurement in gas-filled devices

    International Nuclear Information System (INIS)

    This paper presents realization of a digital embedded system for measuring electrical breakdown time delay. The proposed system consists of three major parts: dc voltage supply, analog subsystem, and a digital subsystem. Any dc power source with the range from 100 to 1000 V can be used in this application. The analog subsystem should provide fast and accurate voltage switching on the testing device as well as transform the signals that represent the voltage pulse on the device and the device breakdown into the form suitable for detection by a digital subsystem. The insulated gate bipolar transistor IRG4PH40KD driven by TC429 MOSFET driver is used for high voltage switching on the device. The aim of a digital subsystem is to detect the signals from the analog subsystem and to measure the elapsed time between their occurrences. Moreover, the digital subsystem controls various parameters that influence time delay and provides fast data storage for a large number of measured data. For this propose, we used the PIC18F4550 microcontroller with a full-speed compatible universal serial bus (USB) engine. Operation of this system is verified on different commercial and custom made gas devices with different structure and breakdown mechanisms. The electrical breakdown time delay measurements have been carried out as a function of several parameters, which dominantly influence electrical breakdown time delay. The obtained results have been verified using statistical methods, and they show good agreement with the theory. The proposed system shows good repeatability, sensitivity, and stability for measuring the electrical breakdown time delay.

  17. Microcontroller based system for electrical breakdown time delay measurement in gas-filled devices

    Science.gov (United States)

    Pejović, Milić M.; Denić, Dragan B.; Pejović, Momčilo M.; Nešić, Nikola T.; Vasović, Nikola

    2010-10-01

    This paper presents realization of a digital embedded system for measuring electrical breakdown time delay. The proposed system consists of three major parts: dc voltage supply, analog subsystem, and a digital subsystem. Any dc power source with the range from 100 to 1000 V can be used in this application. The analog subsystem should provide fast and accurate voltage switching on the testing device as well as transform the signals that represent the voltage pulse on the device and the device breakdown into the form suitable for detection by a digital subsystem. The insulated gate bipolar transistor IRG4PH40KD driven by TC429 MOSFET driver is used for high voltage switching on the device. The aim of a digital subsystem is to detect the signals from the analog subsystem and to measure the elapsed time between their occurrences. Moreover, the digital subsystem controls various parameters that influence time delay and provides fast data storage for a large number of measured data. For this propose, we used the PIC18F4550 microcontroller with a full-speed compatible universal serial bus (USB) engine. Operation of this system is verified on different commercial and custom made gas devices with different structure and breakdown mechanisms. The electrical breakdown time delay measurements have been carried out as a function of several parameters, which dominantly influence electrical breakdown time delay. The obtained results have been verified using statistical methods, and they show good agreement with the theory. The proposed system shows good repeatability, sensitivity, and stability for measuring the electrical breakdown time delay.

  18. Effect of gas flow on transport of O (3Pj) atoms produced in ac power excited non-equilibrium atmospheric-pressure O2/Ar plasma jet

    International Nuclear Information System (INIS)

    The Spatial distribution of O (3Pj) atoms emitted from a non-equilibrium atmospheric-pressure O2/Ar plasma jet in ambient N2 gas has been measured by using the vacuum ultraviolet absorption spectroscopy. In remote regions of the plasma, the absolute density of O (3Pj) atoms for a total gas flow rate of 1 slm decreased from 4.1 × 1014 to 1.5 × 1013 cm−3 as the distance from the main discharge region increased from 10 to 16 mm and that for 5 slm decreased from 7.7 × 1014 to 2.0 × 1014 cm−3. The reduction ratio thus changed from 0.037 to 0.259 with increasing total gas flow rate. Although loss of O (3Pj) atoms occurs frequently due to the influence of N2 or nitrogen oxide species produced by the inflow of ambient gas, it is found that the gas flow velocity is a very important factor for the transport of the active species to longer distances from the plasma, and it determines the material processing performance for a non-equilibrium atmospheric-pressure O2/Ar plasma jet. (paper)

  19. Smoothing single-crystalline SiC surfaces by reactive ion etching using pure NF{sub 3} and NF{sub 3}/Ar mixture gas plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Tasaka, Akimasa, E-mail: aki-tasaka-load@yahoo.co.jp [Department of Molecular Chemistry and Biochemistry, Faculty of Science and Engineering, Doshisha University, 1-3 Miyako-dani, Tatara, Kyotanabe, Kyoto 610-0321, Japan and Department of Applied Chemistry, Graduate School of Engineering, Doshisha University, 1-3 Miyako-dani, Tatara, Kyotanabe, Kyoto 610-0321 (Japan); Kotaka, Yuki [Department of Applied Chemistry, Graduate School of Engineering, Doshisha University, 1-3 Miyako-dani, Tatara, Kyotanabe, Kyoto 610-0321 (Japan); Oda, Atsushi; Saito, Morihiro [Department of Molecular Chemistry and Biochemistry, Faculty of Science and Engineering, Doshisha University, 1-3 Miyako-dani, Tatara, Kyotanabe, Kyoto 610-0321 (Japan); Tojo, Tetsuro [Toyo Tanso Co, Ltd., 5-7-2 Takeshima, Nishi yodogawa-ku, Osaka 555-0011 (Japan); Inaba, Minoru [Department of Molecular Chemistry and Biochemistry, Faculty of Science and Engineering, Doshisha University, 1-3 Miyako-dani, Tatara, Kyotanabe, Kyoto 610-0321, Japan and Department of Applied Chemistry, Graduate School of Science and Engineering, Doshisha University, 1-3 Miyako-dani, Tatara, Kyotanabe, Kyoto 610-0321 (Japan)

    2014-09-01

    In pure NF{sub 3} plasma, the etching rates of four kinds of single-crystalline SiC wafer etched at NF{sub 3} pressure of 2 Pa were the highest and it decreased with an increase in NF{sub 3} pressure. On the other hand, they increased with an increase in radio frequency (RF) power and were the highest at RF power of 200 W. A smooth surface was obtained on the single-crystalline 4H-SiC after reactive ion etching at NF{sub 3}/Ar gas pressure of 2 Pa and addition of Ar to NF{sub 3} plasma increased the smoothness of SiC surface. Scanning electron microscopy observation revealed that the number of pillars decreased with an increase in the Ar-concentration in the NF{sub 3}/Ar mixture gas. The roughness factor (R{sub a}) values were decreased from 51.5 nm to 25.5 nm for the As-cut SiC, from 0.25 nm to 0.20 nm for the Epi-SiC, from 5.0 nm to 0.7 nm for the Si-face mirror-polished SiC, and from 0.20 nm to 0.16 nm for the C-face mirror-polished SiC by adding 60% Ar to the NF{sub 3} gas. Both the R{sub a} values of the Epi- and the C-face mirror-polished wafer surfaces etched using the NF{sub 3}/Ar (40:60) plasma were similar to that treated with mirror polishing, so-called the Catalyst-Referred Etching (CARE) method, with which the lowest roughness of surface was obtained among the chemical mirror polishing methods. Etching duration for smoothing the single-crystalline SiC surface using its treatment was one third of that with the CARE method.

  20. Effects of total CH4/Ar gas pressure on the structures and field electron emission properties of carbon nanomaterials grown by plasma-enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    The effects of total CH4/Ar gas pressure on the growth of carbon nanomaterials on Si (1 0 0) substrate covered with CoO nanoparticles, using plasma-enhanced chemical vapor deposition (PECVD), were investigated. The structures of obtained products were correlated with the total gas pressure and changed from pure carbon nanotubes (CNTs) through hybrid CNTs/graphene sheets (GSs), to pure GSs as the total gas pressure changed from 20 to 4 Torr. The total gas pressure influenced the density of hydrogen radicals and Ar ions in chamber, which in turn determined the degree of how CoO nanoparticles were deoxidized and ion bombardment energy that governed the final carbon nanomaterials. Moreover, the obtained hybrid CNTs/GSs exhibited a lower turn-on field (1.4 V/μm) emission, compared to either 2.7 V/μm for pure CNTs or 2.2 V/μm for pure GSs, at current density of 10 μA/cm2.

  1. Effect of N2 and Ar gas on DC arc plasma generation and film composition from Ti-Al compound cathodes

    International Nuclear Information System (INIS)

    DC arc plasma from Ti, Al, and Ti1−xAlx (x = 0.16, 0.25, 0.50, and 0.70) compound cathodes has been characterized with respect to plasma chemistry (charged particles) and charge-state-resolved ion energy for Ar and N2 pressures in the range 10−6 to 3 × 10−2 Torr. Scanning electron microscopy was used for exploring the correlation between the cathode and film composition, which in turn was correlated with the plasma properties. In an Ar atmosphere, the plasma ion composition showed a reduction of Al of approximately 5 at. % compared to the cathode composition, while deposited films were in accordance with the cathode stoichiometry. Introducing N2 above ∼5 × 10−3 Torr, lead to a reduced Al content in the plasma as well as in the film, and hence a 1:1 correlation between the cathode and film composition cannot be expected in a reactive environment. This may be explained by an influence of the reactive gas on the arc mode and type of erosion of Ti and Al rich contaminations, as well as on the plasma transport. Throughout the investigated pressure range, a higher deposition rate was obtained from cathodes with higher Al content. The origin of generated gas ions was investigated through the velocity rule, stating that the most likely ion velocities of all cathode elements from a compound cathode are equal. The results suggest that the major part of the gas ions in Ar is generated from electron impact ionization, while gas ions in a N2 atmosphere primarily originate from a nitrogen contaminated layer on the cathode surface. The presented results provide a contribution to the understanding processes of plasma generation from compound cathodes. It also allows for a more reasonable approach to the selection of composite cathode and experimental conditions for thin film depositions

  2. Experimental tests of Rayleigh-Taylor stabilization mechanisms with long pulse gas-filled halfraums on OMEGA

    Science.gov (United States)

    Casner, A.; Huser, G.; Vandenboomgaerde, M.; Liberatore, S.; Masse, L.; Galmiche, D.

    2008-11-01

    Mitigation of Rayleigh-Taylor instabilities growth is a key issue on the road toward ignition. The graded doped ablator is a common concept for NIF [1] and LMJ [2] point designs. A complementary stabilization mechanism based on anisotropic thermal diffusion was theoretically underlined [3] for the ablative Rayleigh-Taylor instability. We will present the first ever experimental tests of these mechanisms. Indirect drive experiments were performed on the OMEGA laser facility with a long-pulse platform. We used in fact gas-filled halfraums and stack 15 drive beams along 2 cones to create a 7 ns long radiation drive. Halfraum energetics with E-IDI-300 phase plates was validated by dedicated shots along P5/P8 and is fairly reproduced by the simulations. These drive measurements allowed also to determine the graded doped planar emulator whose layers thicknesses and composition should be carefully optimized . Side-on and face-on data acquired with germanium-doped plastic samples (modulations wavelength 35 and 50 microns) will be presented and compared with FCI2 hydrocodes simulations. [1] S.W. Haan et al., Phys. Plasmas 12, 056316 (2005). [2] C C-Cl'erouin et al 2008 J. Phys.: Conf. Ser. 112 022023 [3] L. Masse., Phys. Rev. Lett. 98, 245001 (2007).

  3. Studies of implosion dynamics of D{sup 3}He gas-filled plastic targets using nuclear diagnostics at OMEGA

    Energy Technology Data Exchange (ETDEWEB)

    Falk, Magnus

    2004-09-01

    Information about target-implosion dynamics is essential for understanding how assembly occurs. Without carefully tailored assembly of the fuel, hot-spot ignition on National Ignition Facility (NIF) will fail. Hot spot ignition relies on shock convergence to 'ignite' the hot spot (shock burn), followed by propagation of the burn into the compressed shell material (compressive burn). The relationship between these events must be understood to ensure the success of Inertial Confinement Fusion (ICF) ignition. To further improve our knowledge about the timing of these events, temporal evolution of areal density (density times radius, normally referred to as {rho}R) and burn of direct-drive, D{sup 3}He gas-filled plastic target implosions have been studied using dd neutrons and d{sup 3}He protons. The proton temporal diagnostic (PTD) code was developed for this purpose. {rho}R asymmetries were observed at shock-bang time (time of peak burn during shock phase) and grew approximately twice as fast as the average {rho}R, without any phase changes. Furthermore, it was observed that the shock-bang and compression-bang time occur earlier, and that the time difference between these events decreases for higher laser energy on target, which indicates that the compression-bang time is more sensitive to the variation of laser energy on target. It was also observed that the duration of shock and compression phase might decrease for higher laser energy on target.

  4. Understanding fast neutrons utilizing a water Cherenkov detector and a gas-filled detector at the soudan underground laboratory

    Science.gov (United States)

    Ghimire, Chiranjibi

    Many experiments are currently searching for Weakly Interactive Massive Particles (WIMPs), a well-motivated class of hypothetical dark matter candidates. These direct dark matter detection experiments are located in deep underground to shield from cosmic-ray muons and the fast neutrons they produce. Fast neutrons are particularly dangerous to WIMP detectors because they can penetrate a WIMP-search experiment's neutron shielding. Once inside, these fast neutrons can interact with high-Z material near the WIMP detector, producing slower neutrons capable of mimicking the expected WIMP signal. My research uses two detectors located in Soudan Underground Laboratory to understand fast neutron production by muons in an underground environment: a water-Cherenkov detector sensitive to fast neutrons; and a gas-filled detector sensitive to charged particles like muons. The different kinds of selection criterion and their efficiencies are reported in this thesis. This thesis estimate the number of high energy neutron-like candidates associated with a nearby muon by using data from both detector systems.

  5. Portable optical frequency standard based on sealed gas-filled hollow-core fiber using a novel encapsulation technique

    Science.gov (United States)

    Triches, Marco; Brusch, Anders; Hald, Jan

    2015-12-01

    A portable stand-alone optical frequency standard based on a gas-filled hollow-core photonic crystal fiber is developed to stabilize a fiber laser to the ^{13}{C}_2{H}_2 P(16) (ν _1 + ν _3) transition at 1542 nm using saturated absorption. A novel encapsulation technique is developed to permanently seal the hollow-core fiber with easy light coupling, showing negligible pressure increase over two months. The locked laser shows a fractional frequency instability below 8 × 10^{-12} for an averaging time up to 104 s. The lock-point repeatability over one month is 2.6 × 10^{-11}, corresponding to a standard deviation of 5.3 kHz. The system is also assembled in a more compact and easy-to-use configuration ( Plug&Play), showing comparable performance with previously published work. The real portability of this technology is proved by shipping the system to a collaborating laboratory, showing unchanged performance after the return.

  6. Development of the Focal Plane Detection System for the Future Gas-Filled Separator at the Cyclotron Institute

    Science.gov (United States)

    Bertelsen, Erin; Mayorov, Dmitriy; Folden, Charles ``Cody'', III

    2015-10-01

    A focal plane detection system is being developed for use with the gas-filled separator previously known as SASSYER (Small Angle Separator System at Yale for Evaporation Residues) that will be installed at the Cyclotron Institute at Texas A&M University. This system will be used to study heavy (Z >= 90) elements and features two 60×40 strip double-sided silicon detectors (DSSDs) and accompanying multiplexing read-out electronics. The DSSDs cover an area of 120×40 mm2 and are read-out by fourteen 16-channel multiplexers (Mesytec MUX-16) that perform the function of a preamplifier, shaper, and leading-edge discriminator in one unit. The multiplexers are controlled by four ``MUX drivers,'' each of which serves as a signal bus for multiple MUX-16 boards. The system allows a single 16-channel ADC to read the combined 200 strips of both DSSDs. A four peak source composed of 148Gd, 239Pu, 241Am, and 244Cm was used to characterize the performance of the system, with a preliminary energy resolution of ~ 60 keV measured for the 241Am alphas. This contribution will discuss the work performed in assembly of the test setup, optimization and performance check of the multiplexers, and the preliminary energy and position data collected with the α-source. Present address: Los Alamos National Laboratory, Los Alamos, NM 87545.

  7. Studies of implosion dynamics of D3He gas-filled plastic targets using nuclear diagnostics at OMEGA

    International Nuclear Information System (INIS)

    Information about target-implosion dynamics is essential for understanding how assembly occurs. Without carefully tailored assembly of the fuel, hot-spot ignition on National Ignition Facility (NIF) will fail. Hot spot ignition relies on shock convergence to 'ignite' the hot spot (shock burn), followed by propagation of the burn into the compressed shell material (compressive burn). The relationship between these events must be understood to ensure the success of Inertial Confinement Fusion (ICF) ignition. To further improve our knowledge about the timing of these events, temporal evolution of areal density (density times radius, normally referred to as ρR) and burn of direct-drive, D3He gas-filled plastic target implosions have been studied using dd neutrons and d3He protons. The proton temporal diagnostic (PTD) code was developed for this purpose. ρR asymmetries were observed at shock-bang time (time of peak burn during shock phase) and grew approximately twice as fast as the average ρR, without any phase changes. Furthermore, it was observed that the shock-bang and compression-bang time occur earlier, and that the time difference between these events decreases for higher laser energy on target, which indicates that the compression-bang time is more sensitive to the variation of laser energy on target. It was also observed that the duration of shock and compression phase might decrease for higher laser energy on target

  8. Measurement of the viscosities of He, Ne and Ar for the determination of their gas – kinetic diameters.

    Directory of Open Access Journals (Sweden)

    P.N. Ekemezie

    2015-11-01

    Full Text Available The viscosities of He, Ne and Ar gases were measured using pressure transducer to obtain the pressure, time data. Using the viscosity of dry air at the measured 320C ambient temperature, the evacuation data (pressure, time were converted to viscosity values thus: He (1.03 x 10-4 poise, Ne (1.72 x 10-4 poise, and Ar (1.96 x 10-4 poise. Finally, the collision diameter of the gases were calculated using appropriate equations to obtain He (0.19nm, Ne (0.22nm, and Ar (0.33nm. The values obtained were compared with those of literature (He = 0.21nm, Ne = 0.24nm, Ar = 0.36nm. Since the values of collision diameter obtained in this experiment are in conformity with those obtained from literature, we can safely conclude that measurement of collision diameter can be used as a quality assay for gases.

  9. Angle-resolved photoemission spectroscopy with 9-eV photon-energy pulses generated in a gas-filled hollow-core photonic crystal fiber

    Energy Technology Data Exchange (ETDEWEB)

    Bromberger, H., E-mail: Hubertus.Bromberger@mpsd.mpg.de; Liu, H.; Chávez-Cervantes, M.; Gierz, I. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Ermolov, A.; Belli, F.; Abdolvand, A.; Russell, P. St. J.; Travers, J. C. [Max Planck Institute for the Science of Light, Günther-Scharowsky-Str. 1, 91058 Erlangen (Germany); Calegari, F. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Institute for Photonics and Nanotechnologies, IFN-CNR, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy); Li, M. T.; Lin, C. T. [Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart (Germany); Cavalleri, A. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Clarendon Laboratory, Department of Physics, University of Oxford, Parks Rd. Oxford OX1 3PU (United Kingdom)

    2015-08-31

    A recently developed source of ultraviolet radiation, based on optical soliton propagation in a gas-filled hollow-core photonic crystal fiber, is applied here to angle-resolved photoemission spectroscopy (ARPES). Near-infrared femtosecond pulses of only few μJ energy generate vacuum ultraviolet radiation between 5.5 and 9 eV inside the gas-filled fiber. These pulses are used to measure the band structure of the topological insulator Bi{sub 2}Se{sub 3} with a signal to noise ratio comparable to that obtained with high order harmonics from a gas jet. The two-order-of-magnitude gain in efficiency promises time-resolved ARPES measurements at repetition rates of hundreds of kHz or even MHz, with photon energies that cover the first Brillouin zone of most materials.

  10. Angle-resolved photoemission spectroscopy with 9-eV photon-energy pulses generated in a gas-filled hollow-core photonic crystal fiber

    CERN Document Server

    Bromberger, H; Belli, F; Liu, H; Calegari, F; Chavez-Cervantes, M; Li, M T; Lin, C T; Abdolvand, A; Russell, P St J; Cavalleri, A; Travers, J C; Gierz, I

    2015-01-01

    A recently developed source of ultraviolet radiation, based on optical soliton propagation in a gas-filled hollow-core photonic crystal fiber, is applied here to angle-resolved photoemission spectroscopy (ARPES). Near-infrared femtosecond pulses of only few {\\mu}J energy generate vacuum ultraviolet (VUV) radiation between 5.5 and 9 eV inside the gas-filled fiber. These pulses are used to measure the band structure of the topological insulator Bi2Se3 with a signal to noise ratio comparable to that obtained with high order harmonics from a gas jet. The two-order-of-magnitude gain in efficiency promises time-resolved ARPES measurements at repetition rates of hundreds of kHz or even MHz, with photon energies that cover the first Brillouin zone of most materials.

  11. Dependence of charge collection distributions and dose on the gas type filling the ionization chamber for a p(66)Be(49) clinical neutron beam

    International Nuclear Information System (INIS)

    Measurements of central axis depth charge distributions (CADCD) in a p(66)Be(49) clinical neutron beam using A-150 TE plastic ionization chambers (IC) have shown that these distributions are dependent on the gas type filling the ICs. IC volumes from 0.1 to 8 cm3 and nine different gases were investigated. Off axis ratios and build-up measurements do not seem to be as sensitive to gas type. The gas dosimetry constants given in the AAPM Protocol for Neutron Beam Dosimetry for air and methane based TE gases were tested for consistency in water and in TE solution filled phantoms at depths of 10 cm, when used in conjunction with an IC having 5 mm thick walls of A-150. 29 refs., 7 figs., 1 tab

  12. Angle-resolved photoemission spectroscopy with 9-eV photon-energy pulses generated in a gas-filled hollow-core photonic crystal fiber

    International Nuclear Information System (INIS)

    A recently developed source of ultraviolet radiation, based on optical soliton propagation in a gas-filled hollow-core photonic crystal fiber, is applied here to angle-resolved photoemission spectroscopy (ARPES). Near-infrared femtosecond pulses of only few μJ energy generate vacuum ultraviolet radiation between 5.5 and 9 eV inside the gas-filled fiber. These pulses are used to measure the band structure of the topological insulator Bi2Se3 with a signal to noise ratio comparable to that obtained with high order harmonics from a gas jet. The two-order-of-magnitude gain in efficiency promises time-resolved ARPES measurements at repetition rates of hundreds of kHz or even MHz, with photon energies that cover the first Brillouin zone of most materials

  13. Late-time radiography of beryllium ignition-target ablators in long-pulse gas-filled hohlraums

    International Nuclear Information System (INIS)

    A multiple-laboratory campaign is underway to qualify beryllium as a fusion capsule ablator for the National Ignition Facility [Moses and Wuest, Fusion Sci. Technol. 43, 420 (2003)]. Although beryllium has many advantages over other ablator materials, individual crystals of beryllium have anisotropic properties, e.g., sound speed, elastic constants, and thermal expansion coefficients, which may seed hydrodynamic instabilities during the implosion phase of ignition experiments. Experiments based on modeling have begun at the OMEGA laser [Boehly, McCrory, Verdon et al., Fusion Eng. Design 44, 35 (1999)] to create a test bed for measuring instability growth rates with face-on radiography of perturbed beryllium samples with the goal of establishing a specification for microstructure in beryllium used as an ablator. The specification would include the size and distribution of sizes of grains and voids and the impurity content. The experimental platform is a 4 kJ laser-heated (for ∼6 ns) hohlraum that is well modeled for radiation temperature and for shock pressure and breakout timing through the driven beryllium sample. A 1 atm methane gas fill has been used to maintain a clear line of sight through the hohlraum for radiography with acceptable plasma backscatter losses. The peak radiation temperature is 145 eV; the pressure early in the laser pulse is 1 Mbar for over 1 ns. Radiographs of sinusoidally perturbed copper-doped (0.9% by atom) beryllium samples have been obtained more than 10 ns after drive initiation. With the current laser drive, a growth factor approaching ten has been measured for initial 2.5 μm perturbations with on-axis radiography

  14. [Time resolved plasma spectroscopy of imploded gas-filled microballoons: The next generation]. Final technical report, 17 April 1995--30 September 1997

    Energy Technology Data Exchange (ETDEWEB)

    Hooper, C.F. Jr.

    1998-03-01

    This report is comprised of three documents which deal with plasma spectroscopy of laser-produced plasmas. In Appendix A the authors present a discussion of plasma line broadening with emphasis on the effects of accounting for ion-dynamic corrections. For two decades, high power lasers have been used to implode microballoons filled with gases such as neon, argon, deuterium, or mixtures of deuterium and argon. These implosions have generated high-temperature ({approx} 1 keV) and high density ({approx} 10{sup 23}/cc--10{sup 25}/cc) plasmas. As a result of these experiments, the authors are able to observe the radiative properties of highly charged ions in the presence of a variety of strongly coupled plasmas. Spectral radiation observed from these experiments is frequently in the x-ray region and the radiative properties are greatly influenced by plasma effects. In section 2 of this paper the authors discuss the theoretical techniques employed to interpret these spectra and describe two sets of implosion experiments. In section 3 they list some conclusions. Appendix B presents more research related to ion-dynamic corrections. The authors examine the combined effects of ion dynamics and opacity on line profiles used in the analysis of hot dense plasmas. Specifically, they have calculated Stark broadened line profiles for both resonance and satellite lines in highly stripped Ar ions, both in the quasi-static ion approximation, and including the effects of ion dynamics. Using the results of an NLTE kinetics code, combined with an escape factor formalism to account for the effects of radiative transfer, they have calculated the relative intensities of these lines, as well as the effects of opacity on their profiles. This model spectra is used in the analysis of experimental data. In a series of experiments performed at the Laboratory for Laser Energetics plastic microballoons filled with DD and doped with Ar were imploded using the Omega laser system. Here, the authors

  15. Density of atoms in Ar*(3p{sup 5}4s) states and gas temperatures in an argon surfatron plasma measured by tunable laser spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Huebner, S.; Carbone, E. A. D.; Mullen, J. J. A. M. van der [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven (Netherlands); Sadeghi, N. [LIPhy, Universite Joseph Fourier and CNRS, UMR 5588, Grenoble F-38041 (France)

    2013-04-14

    This study presents the absolute argon 1 s (in Paschens's notation) densities and the gas temperature, T{sub g}, obtained in a surfatron plasma in the pressure range 0.65gas pressures of p<10 mbar, changes to a Voigt shape at p>10 mbar, for which the pressure broadening can no more be neglected. T{sub g} is in the range of 480-750 K, increasing with pressure and decreasing with the distance from the microwave launcher. Taking into account the line of sight effects of the absorption measurements, a good agreement is found with our previous measurements by Rayleigh scattering of T{sub g} at the tube center. In the studied pressure range, the Ar(4 s) atom densities are in the order of 10{sup 16}-10{sup 18} m{sup -3}, increasing towards the end of the plasma column, decreasing with the pressure. In the low pressure side, a broad minimum is found around 10Ar(4 s) atom densities increase slightly with rising pressure. For the studied pressure range and all axial positions, the density ratio: 1s{sub 5}/1s{sub 4}/1s{sub 3} is very close to a Boltzmann equilibrium by electron impact mixing at the local T{sub e}, which was previously measured by Thomson scattering. The Ar(4 s) densities are successfully compared to a detailed Collisional Radiative Model.

  16. Investigations on Ni-Co-Mn-Sn thin films: Effect of substrate temperature and Ar gas pressure on the martensitic transformations and exchange bias properties

    International Nuclear Information System (INIS)

    We report the effect of substrate temperature (TS) and Ar gas pressure (PD) on the martensitic transformations, magnetic and exchange bias (EB) properties in Heusler type Ni-Co-Mn-Sn epitaxial thin films. Martensitic transformation temperatures and EB fields at 5 K were found to increase with increasing TS. The observed maximum EB value of 320 Oe after field cooling in the film deposited at 650 ∘C is high among the values reported for Ni-Mn-Sn thin films which is attributed to the coexistence of ferromagnetic (FM) and antiferromagnetic (AF) phases in the martensitic state. In the case of PD variation, with increase in PD, martensitic transformation temperatures were increased and a sharp transformation was observed in the film deposited at 0.06 mbar. Magnetization values at 5 K were higher for increasing PD. These observations are attributed to the compositional shift. EB effect is also present in these films. Microstructural features observed using atomic force microscopy (AFM) shows a fine twinning and reduced precipitation with increase in PD, which is also confirmed from the scanning electron microscopy (SEM) images. EB effects in both series were confirmed from the training effect. Target ageing effect has been observed in the films deposited before and after ninety days of time interval. This has been confirmed both on substrate temperature and Ar gas pressure variations

  17. Multistage plasma initiation process by pulsed CO2 laser irradiation of a Ti sample in an ambient gas (He, Ar, or N2)

    Science.gov (United States)

    Hermann, J.; Boulmer-Leborgne, C.; Mihailescu, I. N.; Dubreuil, B.

    1993-02-01

    New experimental results are reported on plasma initiation in front of a titanium sample irradiated by ir (λ=10.6 μm) laser pulses in an ambient gas (He, Ar, and N2) at pressures ranging from several Torr up to the atmosphere. The plasma is studied by space- and time-resolved emission spectroscopy, while sample vaporization is probed by laser-induced fluorescence spectroscopy. Threshold laser intensities leading to the formation of a plasma in the vapor and in the ambient gases are determined. Experimental results support the model of a vaporization mechanism for the plasma initiation (vaporization-initiated plasma breakdown). The plasma initiation is described by simple numerical criteria based on a two-stage process. Theoretical predictions are found to be in a reasonable agreement with the experiment. This study provides also a clear explanation of the influence of the ambient gas on the laser beam-metal surface energy transfer. Laser irradiation always causes an important vaporization when performed in He, while in the case of Ar or N2, the interaction is reduced in heating and vaporization of some surface defects and impurities.

  18. Ionization-induced asymmetric self-phase modulation and universal modulational instability in gas-filled hollow-core photonic crystal fibers

    CERN Document Server

    Saleh, Mohammed F; Travers, John C; Russell, Philip St J; Biancalana, Fabio

    2012-01-01

    We study theoretically the propagation of relatively long pulses with ionizing intensities in a hollow-core photonic crystal fiber filled with a Raman-inactive gas. Due to photoionization, previously unknown types of asymmetric self-phase modulation and `universal' modulational instabilities existing in both normal and anomalous dispersion regions appear. We also show that it is possible to spontaneously generate a plasma-induced continuum of blueshifting solitons, opening up new possibilities for pushing supercontinuum generation towards shorter and shorter wavelengths.

  19. Ars Electronica

    DEFF Research Database (Denmark)

    Kristensen, Thomas Bjørnsten

    2009-01-01

    Anmeldelse af Ars Electronica festivalen 3. - 8. september, 2009 i Linz, Østrig, der fejrede 30 års jubilæum under temaet "Human Nature". Festivalen fokuserer på interaktion mellem menneske, teknologi, kunst og samfund med særlig vægt på udviklingen af computeren og det digitale. Udgivelsesdato: 15.12...

  20. The size and structure of the laser entrance hole in gas-filled hohlraums at the National Ignition Facility

    International Nuclear Information System (INIS)

    At the National Ignition Facility, a thermal X-ray drive is created by laser energy from 192 beams heating the inside walls of a gold cylinder called a “hohlraum.” The x-ray drive heats and implodes a fuel capsule. The laser beams enter the hohlraum via laser entrance holes (LEHs) at each end. The LEH radius decreases as heated plasma from the LEH material blows radially inward but this is largely balanced by hot plasma from the high-intensity region in the center of the LEH pushing radially outward. The x-ray drive on the capsule is deduced by measuring the time evolution and spectra of the x-radiation coming out of the LEH and correcting for geometry and for the radius of the LEH. Previously, the LEH radius was measured using time-integrated images in an x-ray band of 3–5 keV (outside the thermal x-ray region). For gas-filled hohlraums, the measurements showed that the LEH radius is larger than that predicted by the standard High Flux radiation-hydrodynamic model by about 10%. A new platform using a truncated hohlraum (“ViewFactor hohlraum”) is described, which allows time-resolved measurements of the LEH radius at thermal x-ray energies from two views, from outside the hohlraum and from inside the hohlraum. These measurements show that the LEH radius closes during the low power part of the pulse but opens up again at peak power. The LEH radius at peak power is larger than that predicted by the models by about 15%–20% and does not change very much with time. In addition, time-resolved images in a >4 keV (non-thermal) x-ray band show a ring of hot, optically thin gold plasma just inside the optically thick LEH plasma. The structure of this plasma varies with time and with Cross Beam Energy Transfer

  1. The size and structure of the laser entrance hole in gas-filled hohlraums at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, M. B., E-mail: schneider5@llnl.gov; MacLaren, S. A.; Widmann, K.; Meezan, N. B.; Hammer, J. H.; Yoxall, B. E.; Bell, P. M.; Benedetti, L. R.; Bradley, D. K.; Callahan, D. A.; Dewald, E. L.; Döppner, T.; Eder, D. C.; Edwards, M. J.; Hinkel, D. E.; Hsing, W. W.; Kervin, M. L.; Landen, O. L.; Lindl, J. D.; May, M. J. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States); and others

    2015-12-15

    At the National Ignition Facility, a thermal X-ray drive is created by laser energy from 192 beams heating the inside walls of a gold cylinder called a “hohlraum.” The x-ray drive heats and implodes a fuel capsule. The laser beams enter the hohlraum via laser entrance holes (LEHs) at each end. The LEH radius decreases as heated plasma from the LEH material blows radially inward but this is largely balanced by hot plasma from the high-intensity region in the center of the LEH pushing radially outward. The x-ray drive on the capsule is deduced by measuring the time evolution and spectra of the x-radiation coming out of the LEH and correcting for geometry and for the radius of the LEH. Previously, the LEH radius was measured using time-integrated images in an x-ray band of 3–5 keV (outside the thermal x-ray region). For gas-filled hohlraums, the measurements showed that the LEH radius is larger than that predicted by the standard High Flux radiation-hydrodynamic model by about 10%. A new platform using a truncated hohlraum (“ViewFactor hohlraum”) is described, which allows time-resolved measurements of the LEH radius at thermal x-ray energies from two views, from outside the hohlraum and from inside the hohlraum. These measurements show that the LEH radius closes during the low power part of the pulse but opens up again at peak power. The LEH radius at peak power is larger than that predicted by the models by about 15%–20% and does not change very much with time. In addition, time-resolved images in a >4 keV (non-thermal) x-ray band show a ring of hot, optically thin gold plasma just inside the optically thick LEH plasma. The structure of this plasma varies with time and with Cross Beam Energy Transfer.

  2. Analysis of the insulation characteristics of CF3I gas mixtures with Ar, Xe, He, N2, and CO2 using Boltzmann equation method

    Science.gov (United States)

    Deng, Yunkun; Xiao, Dengming

    2014-09-01

    The present study is devoted to the calculation of electron swarm parameters, including the reduced effective ionization coefficient, electron mean energy, and electron drift velocity, for the gas mixtures of CF3I with Ar, Xe, He, N2, and CO2. These data are computed by employing the Boltzmann equation method with two-term approximation in the condition of steady-state Townsend (SST) discharge. For the purpose of evaluating the insulation strength of CF3I gas mixtures, values of the limiting field strength (E/N)lim for which the ionization exactly balances the electron attachment are determined from the variation curves of (α - η)/N. The results indicate that mixtures of CF3I-N2 present the greatest insulation strength among all the combinations for CF3I content varied from 20 to 90%. Furthermore, the gas mixture with 70% CF3I can achieve a very similar dielectric strength to that of SF6. The concerned liquefaction issues are also taken into account to fully assess the possibility of applying CF3I gas mixtures in power equipment as an insulation medium.

  3. First in situ determination of gas transport coefficients (DO2, DAr and DN2) from bulk gas concentration measurements (O2, N2, Ar) in natural sea ice

    DEFF Research Database (Denmark)

    Crabeck, O.; Delille, B.; Rysgaard, Søren;

    2014-01-01

    evolution of an internal gas peak within the ice, we deduced the bulk gas transport coefficients for oxygen (DO2), argon (DAr), and nitrogen (DN2). The values fit to the few existing estimates from experimental work, and are close to the diffusivity values in water (1025 cm2 s21). We suggest that gas...

  4. Laser propagation in a gas-filled target with 0.53 and 0.35 μm at various electron densities on Nova

    International Nuclear Information System (INIS)

    Thin-walled gas-filled targets have been irradiated with the Nova laser in order to measure laser propagation into a gas to form a plasma with electron density ranging from 0.05--0.25 nc. The targets consist of a thin (0.6--1.0 μm) polyimide skin that is stretched across the two faces of a washer, and then inflated to hold 1 atmosphere of gas. The experiments were done with ≤ 1 atmosphere of neopentane (3 mg/cm3). Additional shots were done to propagate a Nova beam into a preformed plasma by using two opposing beams with a relative delay. Peak laser irradiance on the target was varied from 3 x 1014 to 6 x 1015 W/cm2. The beam propagation into the gas was measured from streaked and gated x-ray images taken normal to the direction of laser propagation. Plasma temperature was measured spectroscopically with dopants in the gas-fill mixture. The effect of phase plates and SSD on beam propagation into the gas were studied using an f/4 and an f/8 laser beam on Nova. Lateral heat flow was also measured from the gated x-ray imaging. The propagation of the laser burn-front is compared to LASNEX calculations. A mm-scale plasma is created at approximately 1--1.5 keV with 2--3 kJ of laser energy delivered to the target in a 1 ns square-profile pulse

  5. Effect of glow DBD modulation on gas and thin film chemical composition: case of Ar/SiH4/NH3 mixture

    International Nuclear Information System (INIS)

    In recent years, atmospheric pressure plasma-enhanced chemical vapour deposition has been identified as a convenient way to deposit good quality thin films. With this type of process, where the gas mixture is injected on one side of the electrodes, the chemical composition of the gas evolves with the gas residence time in the plasma. The consequence is a possible gradient in the chemical composition over the thickness of in-line coatings. The present work shows that the modulation of the plasma with a square signal significantly reduces this gradient while the drawback of low growth rate is avoided by increasing the discharge power. This study deals with plane/plane glow dielectric barrier discharges (DBDs) in an Ar/NH3/SiH4 gas mixture to make thin films. The 50 kHz discharge power of the glow DBD was varied by increasing voltage and modulating excitation. The impact on (i) the plasma development was observed through emission spectroscopy and (ii) the thin film coating through Fourier transform infrared measurements. It is shown that the modulation significantly decreases the time and the energy needed to achieve stable chemistry, enhances secondary chemistry and limits disturbance induced by impurities because of a slower decrease of SiH4 concentration and thus a higher ratio of SiH4/impurities, all very important points for in-line AP-PECVD development. When the growth rate is limited by diffusion, coating growth continues when the discharge is off, so long as there is a precursor gradient between the surface and the gas bulk. A higher discharge power steepens this gradient, which enhances diffusion from the bulk and thus growth rate. (paper)

  6. Dependence of the measured 38Ar/36Ar ratio on the total Ar amount and its implications

    International Nuclear Information System (INIS)

    The sensitivity of a mass spectrometer for different isotopes of an element usually is not the same and causes a systematic difference between measured and actual isotopic ratios and is defined as mass discrimination. In noble gas mass spectrometry, the correction factor for mass discrimination can be calculated using a reference gas (air in most cases) with known isotopic composition. The mass discrimination factor (mdf) is defined as the ratio of true isotopic ratio to the measured isotopic ratio. Usually, mdf values, determined using argon in air as standard, are nearly constant for a given element over long periods of time. Both mass discrimination and sensitivity remain the same over a certain range of total pressure in the mass spectrometer, during the measurement of a given gas. For the case of Xe, Kr and Ne, in general, the total gas pressure in the mass spectrometer during the analysis of a sample gas falls within this range and consequently, a fixed value of sensitivity and mdf are used. But in the case of argon and particularly in certain cases (like in ureilites), this may not be true as we deal with samples having a wide range of 40Ar/36Ar ratios (10-3 to 104). It was noticed that the values for 38Ar/36Ar in ureilites (having 40Ar/36Ar 40Ar/36Ar = 295.5. This was the motivation for investigating the pressure effect on the measured ratio of 38Ar/36Ar

  7. Raman-free, noble-gas-filled PCF source for ultrafast, very bright twin-beam squeezed vacuum

    CERN Document Server

    Finger, Martin A; Joly, Nicolas Y; Chekhova, Maria V; Russell, Philip St J

    2015-01-01

    We report a novel source of twin beams based on modulational instability in high-pressure argon-filled hollow-core kagom\\'e-style photonic-crystal fibre. The source is Raman-free and manifests strong photon-number correlations for femtosecond pulses of squeezed vacuum with a record brightness of ~2500 photons per mode. The ultra-broadband (~50 THz) twin beams are frequency tunable and contain one spatial and less than 5 frequency modes.

  8. Performance of gas proportional counters at high pressures

    International Nuclear Information System (INIS)

    The performances of gas proportional counters intended to some isotopes absolute activity measurements are investigated at a gas pressure ranging from 5 to 100 atm. The counter working agent (filling gas) is pure Ar and the CH4/Ar,Xe/Ar,CH4/Xe/Ar gas mixtures. The counter has cathode diameters 6,10,14 mm and anode diameters are 10,16,20 μm. It is found that an addition of 0.5% Xe to Ar results in a considerable decrease (approximately by a factor of 2) of working voltage applied to counters, compared to pure Ar filling, just as maximum gas amplification factor is increased. The counter energy resolution is 5.5-7% (FWHM) for 241Am γ-quanta with the 59.57 keV energy at Ar+0.5% Xe mixture pressure ranging from 8 to 100 atm. It is shown that it is more efficiently to use argon with addition of xenon, but no methan for stabilization of the gas counters performance at high pressures

  9. Gas isotopic signatures (He, C, and Ar) in the Lake Kivu region (western branch of the East African rift system): Geodynamic and volcanological implications

    Science.gov (United States)

    Tedesco, D.; Tassi, F.; Vaselli, O.; Poreda, R. J.; Darrah, T.; Cuoco, E.; Yalire, M. M.

    2010-01-01

    On 17 January 2002, the city of Goma was partly destroyed by two of the several lava flows erupted from a roughly N-S oriented fracture system opened along the southern flank of Mount Nyiragongo (Democratic Republic of Congo), in the western branch of the East African rift system. A humanitarian and scientific response was promptly organized by international, governmental, and nongovernmental agencies coordinated by the United Nations and the European Union. Among the different scientific projects undertaken to study the mechanisms triggering this and possible future eruptions, we focused on the isotopic (He, C, and Ar) analysis of the magmatic-hydrothermal and cold gas discharges related to the Nyiragongo volcanic system, the Kivu and Virunga region. The studied area includes the Nyiragongo volcano, its surroundings, and peripheral areas inside and outside the rift. They have been subdivided into seven regions characterized by distinct 3He/4He (expressed as R/Rair) ratios and/or δ13C-CO2 values. The Nyiragongo summit crater fumaroles, whose R/Rair and δ13C-CO2 values are up to 8.73 and from -3.5‰ to -4.0‰ VPDB, respectively, show a clear mantle, mid-ocean ridge basalt (MORB)-like contribution. Similar mantle-like He isotopic values (6.5-8.3 R/Rair) are also found in CO2-rich gas emanations (mazukus) along the northern shoreline of Lake Kivu main basin, whereas the 13δC-CO2 values range from -5.3‰ to -6.8‰ VPDB. The mantle influence progressively decreases in (1) dissolved gases of Lake Kivu (2.6-5.5 R/Rair) and (2) the distal gas discharges within and outside the two sides of the rift (from 0.1 to 1.7 R/Rair). Similarly, δ13C-CO2 ratios of the peripheral gas emissions are lighter (from -5.9‰ to -11.6‰ VPDB) than those of the crater fumaroles. Therefore, the spatial distribution of He and C signatures in the Lake Kivu region is mainly produced by mixing of mantle-related (e.g., Nyiragongo crater fumaroles and/or mazukus gases) and crustal-related (e

  10. Plasma-induced asymmetric self-phase modulation and modulational instability in gas-filled hollow-core photonic crystal fibers.

    Science.gov (United States)

    Saleh, Mohammed F; Chang, Wonkeun; Travers, John C; Russell, Philip St J; Biancalana, Fabio

    2012-09-14

    We study theoretically the propagation of relatively long pulses with ionizing intensities in a hollow-core photonic crystal fiber filled with a Raman-inactive noble gas. Because of photoionization, an extremely asymmetric self-phase modulation and a new kind of "universal" plasma-induced modulational instability appear in both normal and anomalous dispersion regions. We also show that it is possible to spontaneously generate a plasma-induced continuum of blueshifting solitons, opening up new possibilities for pushing supercontinuum generation towards shorter and shorter wavelengths. PMID:23005629

  11. Corrosion behavior of Hastelloy-N alloys in molten salt fluoride in Ar gas or in air

    International Nuclear Information System (INIS)

    The effects of air on the corrosion of Hastelloy-N alloys in molten salt coolant containing fission product elements were investigated to determine the safety of structural materials in high-temperature reactors cooled with fluoride salt. Corrosion tests of Hastelloy-N in the molten fluoride salt FLiNaK in an alumina crucible and a graphite crucible under argon gas or air were performed at 773–923 K for 100 h. The depth of corrosive attack, as well as the extent of chromium and molybdenum depletion, increased with increasing temperature. The extent of Hastelloy-N corrosion in molten salt under air was significantly greater than under argon gas. The effect of adding the impurity cesium iodide to molten salt containing nuclear waste fuel on the corrosion behavior was negligible. (author)

  12. Ordering and growth of rare gas films (Xe, Kr, Ar, and Ne) on the pseudo-ten-fold quasicrystalline approximant Al13Co4(100) surface

    International Nuclear Information System (INIS)

    Adsorption of the rare gases Kr, Ar, and Ne on the complex alloy surface Al13Co4(100) was studied using grand canonical Monte Carlo (GCMC) computer simulations. This surface is an approximant to the ten-fold decagonal Al–Ni–Co quasicrystalline surface, on which rare gas adsorption was studied previously. Comparison of adsorption results on the periodic Al13Co4(100) surface with those of the quasiperiodic Al–Ni–Co surface indicates some similarities, such as layer-by-layer growth, and some dissimilarities, such as the formation of Archimedes tiling phases (Mikhael et al 2008 Nature 454 501, Shechtman et al 1984 Phys. Rev. Lett. 53 1951, Macia 2006 Rep. Prog. Phys. 69 397, Schmiedeberg et al 2010 Eur. Phys. J. E 32 25–34, Kromer et al 2012 Phys. Rev. Lett. 108 218301, Schmiedeberg and Stark 2008 Phys. Rev. Lett. 101 218302). The conditions under which Archimedes tiling phases (ATP) emerge on Al13Co4(100) are examined and their presence is related to the gas–gas and gas–surface interaction parameters. (paper)

  13. Dramatic Raman Gain Suppression in the Vicinity of the Zero Dispersion Point in Gas-Filled Hollow-Core Photonic Crystal Fiber

    CERN Document Server

    Bauerschmidt, Sebastian T; Russell, Philip St J

    2015-01-01

    In 1964 Bloembergen and Shen predicted that Raman gain could be suppressed if the rates of phonon creation and annihilation (by inelastic scattering) exactly balance. This is only possible if the momentum required for each process is identical, i.e., phonon coherence waves created by pump-to-Stokes scattering are identical to those annihilated in pump-to-anti-Stokes scattering. In bulk gas cells, this can only be achieved over limited interaction lengths at an oblique angle to the pump axis. Here we report a simple system that provides dramatic Raman gain suppression over long collinear path-lengths in hydrogen. It consists of a gas-filled hollow-core photonic crystal fiber whose zero dispersion point is pressure-adjusted to lie close to the pump laser wavelength. At a certain precise pressure, generation of Stokes light in the fundamental mode is completely suppressed, allowing other much weaker nonlinear processes to be explored.

  14. The self–vibrations of cylindrical shell, filled by the flowing non viscous Gas-Liquid mixture

    Directory of Open Access Journals (Sweden)

    Ohanyan G.G.

    2014-03-01

    Full Text Available The problem of non-symmetrical self–vibrations of the infinite long shell, filled by the flowing non viscous Liquid with large or small sizes of bubbles is considered. The subsonic regime of the shell–mixture system with small bubbles which vibration frequencies exceed the frequencies values of those with the large bubbles is considered. The frequency values of the system is increased, when shell thickness and flow speed are increased as when vibration modes are decreased analogous to the case of shell with the pure liquids.

  15. Spectrum Blueshifting of Ultrashort UV Laser Pulse Induced by Ionization of Supersonic He and Ar Gas Jets

    Institute of Scientific and Technical Information of China (English)

    YAN Lixin; ZHANG Yongsheng; LIU Jingru; HUANG Wenhui; TANG Chuanxiang; CHENG Jianping

    2008-01-01

    The predominant spectral blueshifting of a sub-picosecond UV laser pulse induced by ultrafast ionization of noble gases was investigated. Spectral measurements were made at various gas densities. Typical quasi-periodic structures in the blueshifted spectrum were obtained. The observations were in connection with the so-called self-phase modulation of laser pulses in the ultrafast ionization process which was simply simulated with an ADK (Ammosov-Delone-Krainov) ionization model. Some quantitative information can be deduced from the measurements and calculations.

  16. Enfoque “Aprendizaje Basado en Proyectos” para enseñar sistemas de potencia de gas y vapor

    Directory of Open Access Journals (Sweden)

    Asier Aranzábal

    2014-12-01

    Full Text Available El objetivo de este trabajo es presentar la experiencia y los resultados derivados de la aplicación del método Aprendizaje Basado en Proyectos (PBL en la asignatura Termotecnia de la Titulación de Ingeniería Química de la Universidad del País Vasco/Euskal Herriko Unibertsitatea, para aprender sistemas de potencia de gas y vapor. Tras un análisis crítico de los resultados académicos de los alumnos que aprenden estos sistemas, se observa que la estrategia de enseñanza-aprendizaje tradicional, basada en clases “magistrales + clases de aplicación en una lista de ejercicios (totalmente acotados y con una solución única, estaba fallando. Ante esta situación se plantea un enfoque constructivista centrado en el alumno para que él mismo construya su aprendizaje activa y cooperativamente, y no escuchando clases magistrales, ni memorizando.

  17. Simulation of the transition radiation detection conditions in the ATLAS TRT detector filled with argon and krypton gas mixtures

    International Nuclear Information System (INIS)

    Performance of the Transition Radiation Tracker (TRT) at the ATLAS experiment with argon and krypton gas mixtures was simulated. The efficiency of transition radiation registration, which is necessary for electron identification, was estimated along with the electron identification capabilities under such conditions

  18. Simulation of the transition radiation detection conditions in the ATLAS TRT detector filled with argon and krypton gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Boldyrev, A. S., E-mail: Alexey.Boldyrev@cern.ch [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation); Maevskiy, A. S., E-mail: Artem.Maevskiy@cern.ch [Moscow State University, Faculty of Physics (Russian Federation)

    2015-12-15

    Performance of the Transition Radiation Tracker (TRT) at the ATLAS experiment with argon and krypton gas mixtures was simulated. The efficiency of transition radiation registration, which is necessary for electron identification, was estimated along with the electron identification capabilities under such conditions.

  19. Understanding the amorphous-to-microcrystalline silicon transition in SiF{sub 4}/H{sub 2}/Ar gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Dornstetter, Jean-Christophe [TOTAL New Energies, 24 cours Michelet, 92069 Paris La Défense Cedex (France); LPICM-CNRS, Ecole Polytechnique, 91128 Palaiseau (France); Bruneau, Bastien; Bulkin, Pavel; Johnson, Erik V.; Roca i Cabarrocas, Pere [LPICM-CNRS, Ecole Polytechnique, 91128 Palaiseau (France)

    2014-06-21

    We report on the growth of microcrystalline silicon films from the dissociation of SiF{sub 4}/H{sub 2}/Ar gas mixtures. For this growth chemistry, the formation of HF molecules provides a clear signature of the amorphous to microcrystalline growth transition. Depositing films from silicon tetrafluoride requires the removal of F produced by SiF{sub 4} dissociation, and this removal is promoted by the addition of H{sub 2} which strongly reacts with F to form HF molecules. At low H{sub 2} flow rates, the films grow amorphous as all the available hydrogen is consumed to form HF. Above a critical flow rate, corresponding to the full removal of F, microcrystalline films are produced as there is an excess of atomic hydrogen in the plasma. A simple yet accurate phenomenological model is proposed to explain the SiF{sub 4}/H{sub 2} plasma chemistry in accordance with experimental data. This model provides some rules of thumb to achieve high deposition rates for microcrystalline silicon, namely, that increased RF power must be balanced by an increased H{sub 2} flow rate.

  20. Mechanism and computational model for Lyman-α-radiation generation by high-intensity-laser four-wave mixing in Kr-Ar gas

    Science.gov (United States)

    Louchev, Oleg A.; Bakule, Pavel; Saito, Norihito; Wada, Satoshi; Yokoyama, Koji; Ishida, Katsuhiko; Iwasaki, Masahiko

    2011-09-01

    We present a theoretical model combined with a computational study of a laser four-wave mixing process under optical discharge in which the non-steady-state four-wave amplitude equations are integrated with the kinetic equations of initial optical discharge and electron avalanche ionization in Kr-Ar gas. The model is validated by earlier experimental data showing strong inhibition of the generation of pulsed, tunable Lyman-α (Ly-α) radiation when using sum-difference frequency mixing of 212.6 nm and tunable infrared radiation (820-850 nm). The rigorous computational approach to the problem reveals the possibility and mechanism of strong auto-oscillations in sum-difference resonant Ly-α generation due to the combined effect of (i) 212.6-nm (2+1)-photon ionization producing initial electrons, followed by (ii) the electron avalanche dominated by 843-nm radiation, and (iii) the final breakdown of the phase matching condition. The model shows that the final efficiency of Ly-α radiation generation can achieve a value of ˜5×10-4 which is restricted by the total combined absorption of the fundamental and generated radiation.

  1. Mechanism and computational model for Lyman-{alpha}-radiation generation by high-intensity-laser four-wave mixing in Kr-Ar gas

    Energy Technology Data Exchange (ETDEWEB)

    Louchev, Oleg A.; Saito, Norihito; Wada, Satoshi [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Bakule, Pavel [STFC, ISIS Facility, Rutherford Appleton Laboratory, Chilton, Oxfordshire OX11 0QX (United Kingdom); Yokoyama, Koji [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Advanced Meson Science Laboratory, RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan); Ishida, Katsuhiko; Iwasaki, Masahiko [Advanced Meson Science Laboratory, RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan)

    2011-09-15

    We present a theoretical model combined with a computational study of a laser four-wave mixing process under optical discharge in which the non-steady-state four-wave amplitude equations are integrated with the kinetic equations of initial optical discharge and electron avalanche ionization in Kr-Ar gas. The model is validated by earlier experimental data showing strong inhibition of the generation of pulsed, tunable Lyman-{alpha} (Ly-{alpha}) radiation when using sum-difference frequency mixing of 212.6 nm and tunable infrared radiation (820-850 nm). The rigorous computational approach to the problem reveals the possibility and mechanism of strong auto-oscillations in sum-difference resonant Ly-{alpha} generation due to the combined effect of (i) 212.6-nm (2+1)-photon ionization producing initial electrons, followed by (ii) the electron avalanche dominated by 843-nm radiation, and (iii) the final breakdown of the phase matching condition. The model shows that the final efficiency of Ly-{alpha} radiation generation can achieve a value of {approx}5x10{sup -4} which is restricted by the total combined absorption of the fundamental and generated radiation.

  2. Development of VUV wavelength shifter for the use with a visible light photodetector in noble gas filled detectors

    Energy Technology Data Exchange (ETDEWEB)

    Akimov, D.Yu., E-mail: akimov_d@itep.ru [State Scientific Centre of Russian Federation Institute for Theoretical and Experimental Physics (ITEP), 25 Bolshaya Cheremushkinskaya street, 117218 Moscow (Russian Federation); Akindinov, A.V.; Alexandrov, I.S.; Belov, V.A. [State Scientific Centre of Russian Federation Institute for Theoretical and Experimental Physics (ITEP), 25 Bolshaya Cheremushkinskaya street, 117218 Moscow (Russian Federation); Borshchev, O.V. [Enikolopov Institute of Synthetic Polymer Materials, Russian Academy of Science, 70 Profsoyuznaya street, 117393 Moscow (Russian Federation); Burenkov, A.A.; Danilov, M.V.; Kovalenko, A.G. [State Scientific Centre of Russian Federation Institute for Theoretical and Experimental Physics (ITEP), 25 Bolshaya Cheremushkinskaya street, 117218 Moscow (Russian Federation); Luponosov, Y.N.; Ponomarenko, S.A. [Enikolopov Institute of Synthetic Polymer Materials, Russian Academy of Science, 70 Profsoyuznaya street, 117393 Moscow (Russian Federation); Stekhanov, V.N. [State Scientific Centre of Russian Federation Institute for Theoretical and Experimental Physics (ITEP), 25 Bolshaya Cheremushkinskaya street, 117218 Moscow (Russian Federation); Surin, N.M. [Enikolopov Institute of Synthetic Polymer Materials, Russian Academy of Science, 70 Profsoyuznaya street, 117393 Moscow (Russian Federation); Zav' yalov, S.A. [State Scientific Centre of Russian Federation Karpov Institute of Physical Chemistry, 10 Vorontsovo Pole street, 105064 Moscow (Russian Federation); Yablokov, M.Yu. [Enikolopov Institute of Synthetic Polymer Materials, Russian Academy of Science, 70 Profsoyuznaya street, 117393 Moscow (Russian Federation)

    2012-12-11

    Development study of a wavelength shifter (WLS) to convert a noble gas emission light from the VUV region to the visible range is presented. The shifter is developed for the use with an array of blue-sensitive multipixel avalanche Geiger photodiodes (MRS APD) to detect Xe 175 nm emission. It was found that a polycrystalline p-terphenyl having an absorption peak at 180 nm with a molar extinction coefficient {epsilon} of 37500{+-}5000 mol{sup -1}{center_dot}l cm{sup -1} is well suited for this. To satisfy a requirement of compatibility with an extra pure noble gas detection medium the p-terphenyl layer was coated with an {approx}1 {mu}m thick poly-para-xylylene protection film. A new WLS with maximum of emission spectrum at 390 nm and at 420 nm is developed on the basis of a nanostructured organosilicon luminophore.

  3. Azaporphine guest-host complexes in solution and gas-phase: evidence for partially filled nanoprisms and exchange reactions

    OpenAIRE

    Weis, Patrick; Schwarz, Ulrike; Hennrich, Frank; Wagner, Danny; Bräse, Stefan; Kappes, Manfred

    2015-01-01

    Supramolecular guest-host complexes comprising various azaporphines stacked in a coordination nanoprism consisting of tris(4-pyridyl)triazines as panels{,} 1{,}4-bis(pyridyl)benzenes as pillars and (en)Pd as hinges were synthesized according to the procedure of Fujita and coworkers and characterized as ions in the gas-phase by high-resolution electrospray ionization mass spectrometry and collision induced dissociation as well as in solution by analytical ultracentrifugation. Apart from fully ...

  4. Shaping frequency correlations of ultrafast pulse-pumped modulational instability in gas-filled hollow-core PCF

    CERN Document Server

    Finger, Martin A; Russell, Philip St J; Chekhova, Maria V

    2016-01-01

    We vary the time-frequency mode structure of ultrafast pulse-pumped modulational instability (MI) in an argon-filled hollow-core kagom\\'e-style PCF by adjusting the pressure, pump pulse chirp, fiber length and parametric gain. Compared to solid-core systems, the pressure dependent dispersion landscape brings increased flexibility to the tailoring of frequency correlations. The resulting mode content is characterized by measuring the multimode second-order correlation function g(2) and by directly observing frequency correlations in single-shot MI spectra. We show that, from such measurements, the shapes and weights of time-frequency Schmidt (TFS) modes can be extracted and that the number of modes directly influences the shot-to-shot pulse-energy and spectral-shape fluctuations in MI. Using this approach we are able to change the number of TFS modes from 1.3 (g(2) = 1.75) to 4 (g(2) = 1.25) using only a single fiber.

  5. Performance of a gas flow ionization detector filled with He-iso-C4H10 mixtures for STIM-T

    International Nuclear Information System (INIS)

    A cylindrical gas flow ionization chamber has been developed for measuring particle energy in Scanning Transmission Ion Microscopy Tomography (STIM-T) experiments due to its ability to withstand the direct beam. The response of a He-iso-C4H10 filled ionization detector to 2 MeV H+ and He+ beams was studied. Different operating parameters, such as concentration of isobutane (in the range of 55–100%), anode voltage, amplifier shaping time, the geometry of the detector entrance canal and the solid angle of the detector, were investigated. The stable operating plateau and the anode voltage at which the best energy resolution is attained were also determined for every gas mixture. The best energy resolution achieved so far for 2 MeV H+ and He+ static beams was ∼1.3%, which is comparable to that of Si PIN diode detectors (in the range of 15–30 keV). Computed tomography (CT) was applied to a set of STIM projections acquired with the gas ionization chamber at the IST/CTN microprobe beam line in order to visualize the 3D-mass distribution in a test structure

  6. Performance of a gas flow ionization detector filled with He-iso-C{sub 4}H{sub 10} mixtures for STIM-T

    Energy Technology Data Exchange (ETDEWEB)

    Marques, A.C. [IST/IPFN, Universidade de Lisboa, Campus Tecnológico e Nuclear, E.N.10, 2695-066 Bobadela LRS (Portugal); Centro de Física Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); Fraga, M.M.F.R. [Laboratório de Instrumentação e Física Experimental de Partículas, 3004-516 Coimbra (Portugal); Departamento de Física, Universidade de Coimbra, 3004-516 Coimbra (Portugal); Fonte, P. [Laboratório de Instrumentação e Física Experimental de Partículas, 3004-516 Coimbra (Portugal); Instituto Superior de Engenharia de Coimbra, 3030-199 Coimbra (Portugal); Beasley, D.G. [IST/C2TN, Universidade de Lisboa, Campus Tecnológico e Nuclear, E.N.10, 2695-066 Bobadela LRS (Portugal); Cruz, C. [IST/IPFN, Universidade de Lisboa, Campus Tecnológico e Nuclear, E.N.10, 2695-066 Bobadela LRS (Portugal); Alves, L.C. [IST/C2TN, Universidade de Lisboa, Campus Tecnológico e Nuclear, E.N.10, 2695-066 Bobadela LRS (Portugal); Centro de Física Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); Silva, R.C. da [IST/IPFN, Universidade de Lisboa, Campus Tecnológico e Nuclear, E.N.10, 2695-066 Bobadela LRS (Portugal); Centro de Física Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal)

    2015-04-01

    A cylindrical gas flow ionization chamber has been developed for measuring particle energy in Scanning Transmission Ion Microscopy Tomography (STIM-T) experiments due to its ability to withstand the direct beam. The response of a He-iso-C{sub 4}H{sub 10} filled ionization detector to 2 MeV H{sup +} and He{sup +} beams was studied. Different operating parameters, such as concentration of isobutane (in the range of 55–100%), anode voltage, amplifier shaping time, the geometry of the detector entrance canal and the solid angle of the detector, were investigated. The stable operating plateau and the anode voltage at which the best energy resolution is attained were also determined for every gas mixture. The best energy resolution achieved so far for 2 MeV H{sup +} and He{sup +} static beams was ∼1.3%, which is comparable to that of Si PIN diode detectors (in the range of 15–30 keV). Computed tomography (CT) was applied to a set of STIM projections acquired with the gas ionization chamber at the IST/CTN microprobe beam line in order to visualize the 3D-mass distribution in a test structure.

  7. Three sources and three components of success in detection of ultra-rare alpha decays at the Dubna Gas-Filled Recoil separator

    CERN Document Server

    Tsyganov, Y S

    2015-01-01

    General philosophy of procedure of detecting rare events in the recent experiments with 48Ca projectile at the Dubna Gas-Filled Recoil Separator(DGFRS) aimed to the synthesis of superheavy elements (SHE) has been reviewed. Specific instruments and methods are under consideration. Some historical sources of the successful experiments for Z=112-118 are considered too. Special attention is paid to application of method of active correlations in heavy-ion induced complete fusion nuclear reactions. Example of application in Z=115 experiment is presented. Brief description of the 243Am + 48Ca -> 291-x115+xn experiment is presented too. Some attention is paid to the role of chemical experiments in discoveries of SHEs. The DGFRS detection/monitoring system is presented in full firstly.

  8. Amplification of spontaneous emission of neon-like argon in a fast gas-filled capillary discharge

    Czech Academy of Sciences Publication Activity Database

    Koláček, Karel; Schmidt, Jiří; Boháček, Vladislav; Řípa, Milan; Frolov, Oleksandr; Vrba, Pavel; Štraus, Jaroslav; Prukner, Václav; Rupasov, A. A.; Shikanov, A. S.

    2008-01-01

    Roč. 34, č. 2 (2008), s. 162-168. ISSN 1063-780X R&D Projects: GA ČR GA202/06/1324; GA MŠk LA08024; GA AV ČR KJB100430702; GA AV ČR KAN300100702 Institutional research plan: CEZ:AV0Z20430508 Keywords : soft X-ray * laser * fast high-current * capillary discharge Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.785, year: 2008

  9. Ar-Ar_Redux: rigorous error propagation of 40Ar/39Ar data, including covariances

    Science.gov (United States)

    Vermeesch, P.

    2015-12-01

    Rigorous data reduction and error propagation algorithms are needed to realise Earthtime's objective to improve the interlaboratory accuracy of 40Ar/39Ar dating to better than 1% and thereby facilitate the comparison and combination of the K-Ar and U-Pb chronometers. Ar-Ar_Redux is a new data reduction protocol and software program for 40Ar/39Ar geochronology which takes into account two previously underappreciated aspects of the method: 1. 40Ar/39Ar measurements are compositional dataIn its simplest form, the 40Ar/39Ar age equation can be written as: t = log(1+J [40Ar/39Ar-298.5636Ar/39Ar])/λ = log(1 + JR)/λ Where λ is the 40K decay constant and J is the irradiation parameter. The age t does not depend on the absolute abundances of the three argon isotopes but only on their relative ratios. Thus, the 36Ar, 39Ar and 40Ar abundances can be normalised to unity and plotted on a ternary diagram or 'simplex'. Argon isotopic data are therefore subject to the peculiar mathematics of 'compositional data', sensu Aitchison (1986, The Statistical Analysis of Compositional Data, Chapman & Hall). 2. Correlated errors are pervasive throughout the 40Ar/39Ar methodCurrent data reduction protocols for 40Ar/39Ar geochronology propagate the age uncertainty as follows: σ2(t) = [J2 σ2(R) + R2 σ2(J)] / [λ2 (1 + R J)], which implies zero covariance between R and J. In reality, however, significant error correlations are found in every step of the 40Ar/39Ar data acquisition and processing, in both single and multi collector instruments, during blank, interference and decay corrections, age calculation etc. Ar-Ar_Redux revisits every aspect of the 40Ar/39Ar method by casting the raw mass spectrometer data into a contingency table of logratios, which automatically keeps track of all covariances in a compositional context. Application of the method to real data reveals strong correlations (r2 of up to 0.9) between age measurements within a single irradiation batch. Propertly taking

  10. Electron scattering from 36Ar and 40Ar

    International Nuclear Information System (INIS)

    The argon isotopes, 36Ar and 40Ar, have been investigated using electron scattering at the high-resolution Linac facilities of the National Bureau of Standards. Both elastic scattering and scattering to low-lying states have been observed. A high-pressure, low-volume gas target cell was designed and developed for this experiment. The cell features a transmission geometry and has resolution comparable to solid targets. Spectra were obtained at incident beam energies ranging from 65 to 115 MeV at scattering angles of 92.50 and 1100. Values obtained for the rms charge radii are 3.327 +- 0.015 and 3.393 +- 0.015 fm for 36Ar and 40Ar respectively. A sensitive measurement was made of the difference in the two radii yielding a value of Δ r = 0.079 +- 0.006 fm. The inelastic levels observed are the 1.97 (2+) and 4.18 MeV (3-) levels in 36Ar, and the 1.46 (2+), 2.52 (2+), 3.21 (2+), and 3.68 MeV (3-) levels in 40Ar. A Tassie model analysis was made of the inelastic transitions in the DWBA approximation and transition strengths of these levels were extracted

  11. Standard practice for examination of Gas-Filled filament-wound composite pressure vessels using acoustic emission

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice provides guidelines for acoustic emission (AE) examination of filament-wound composite pressure vessels, for example, the type used for fuel tanks in vehicles which use natural gas fuel. 1.2 This practice requires pressurization to a level equal to or greater than what is encountered in normal use. The tanks' pressurization history must be known in order to use this practice. Pressurization medium may be gas or liquid. 1.3 This practice is limited to vessels designed for less than 690 bar [10,000 psi] maximum allowable working pressure and water volume less than 1 m3 or 1000 L [35.4 ft3]. 1.4 AE measurements are used to detect emission sources. Other nondestructive examination (NDE) methods may be used to gain additional insight into the emission source. Procedures for other NDE methods are beyond the scope of this practice. 1.5 This practice applies to examination of new and in-service filament-wound composite pressure vessels. 1.6 This practice applies to examinations conducted at amb...

  12. 39Ar/Ar measurements using ultra-low background proportional counters

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Jeter C.; Aalseth, Craig E.; Bonicalzi, Ricco; Brandenberger, Jill M.; Day, Anthony R.; Humble, Paul H.; Mace, Emily K.; Panisko, Mark E.; Seifert, Allen

    2016-01-08

    Age dating groundwater and seawater using 39Ar/Ar ratios is an important tool to understand water mass flow rates and mean residence time. For modern or contemporary argon, the 39Ar activity is 1.8 mBq per liter of argon. Radiation measurements at these activity levels require ultra low-background detectors. Low-background proportional counters have been developed at Pacific Northwest National Laboratory. These detectors use traditional mixtures of argon and methane as counting gas, and the residual 39Ar from commercial argon has become a predominant source of background activity in these detectors. We demonstrated sensitivity to 39Ar by using geological or ancient argon from gas wells in place of commercial argon. The low level counting performance of these proportional counters is then demonstrated for sensitivities to 39Ar/Ar ratios sufficient to date water masses as old as 1000 years.

  13. Surface reactivity of molybdenum thin films exposed to (Ar-N{sub 2}-H{sub 2}) expanding microwave plasma at low temperature: influence of the addition of H{sub 2} gas in the plasma

    Energy Technology Data Exchange (ETDEWEB)

    Jauberteau, I [UMR 6638 CNRS, SPCTS, Faculte des Sciences et Techniques, F-87060 Limoges cedex (France); Jauberteau, J L [UMR 6638 CNRS, SPCTS, Faculte des Sciences et Techniques, F-87060 Limoges cedex (France); Cahoreau, M [UMR 6630 CNRS, SP2MI, UFR des Sciences, Bd3, Teleport 2, BP 179, F-86960 Futuroscope (France); Aubreton, J [UMR 6638 CNRS, SPCTS, Faculte des Sciences et Techniques, F-87060 Limoges cedex (France)

    2005-10-07

    The rapid transfer of a large amount of nitrogen into the surface layers followed by diffusion into the inner layers occurs in thin molybdenum films exposed to expanding microwave plasma using (Ar-35%N{sub 2}) and (Ar-25%N{sub 2}-30%H{sub 2}) gas mixtures. The nitrogen transfer into the surface layers nearly correlates to a Gaussian distribution law, which is explained by the formation of a large number of defects at the film surface in which nitrogen piles up before diffusing into the inner metal layers. Such an effect could be induced by the impinging energetic plasma species as ions, NH{sub x<3} radicals. The diffusion part is successfully fitted to Fick's second law by introducing diffusion coefficients of about (5-7) x 10{sup -14} cm{sup 2} s{sup -1} at 673 K. These values are lower than the diffusion coefficient calculated for a solid solution of nitrogen in molybdenum which is equal to about 4 x 10{sup -13} cm{sup 2} s{sup -1}. A surprisingly high diffusion coefficient of about 3 x 10{sup -13} cm{sup 2} s{sup -1} is found for the molybdenum film exposed to (Ar-25%N{sub 2}-30%H{sub 2}) plasma at room temperature. These results highlight the role of plasma hydrogen species on the enhancement of the metal surface reactivity and nitrogen diffusion into the inner metal layers. A modification of the morphology of the film surface exposed to hydrogen species is also seen. The values of electron densities measured in the various (Ar-N{sub 2}-H{sub 2}) gas mixtures are consistent with the formation of expanded plasma far from the centre of the discharge, apart from(Ar-30%N{sub 2}-12%H{sub 2}) where the plasma expansion is very low. At a distance of 10.5 cm from the centre of the discharge, the electron density is equal to about 1.66 x 10{sup 17} m{sup -3} and 1.16 x 10{sup 17} m{sup -3} for (Ar-25%N{sub 2}-30%H{sub 2}) and (Ar-35%N{sub 2}) gas mixtures, respectively.

  14. Nabucco Turks filled with gas from Iran. Turkish state company TPAO has invested in one of the largest gas deposits in the world

    International Nuclear Information System (INIS)

    Planned European Nabucco pipeline has a chance to meet - Iranian natural gas. Turkey can help. Energy ministers of Iran and Turkey, namely last week (November 2009) during the visit of Turkish Prime Minister Recep Erdogan to Tehran signed intergovernmental memorandum of understanding on energy.

  15. The GEM photomultiplier operated with noble gas mixtures

    International Nuclear Information System (INIS)

    We present the results of detailed investigations of the Gas Electron Multiplier (GEM)-based photomultiplier, consisting of a solid CsI photocathode coupled to a cascade of GEM elements. The detector is filled with non-ageing mixtures based on noble gases: Ar, Ne, Ar+Ne, Ar+Xe, Ar+CH4 and Ar+N2. Very high gas gains, reaching 106, and rather fast anode pulses, of a width of 10 ns, were observed in some mixtures. Various phenomena and physical processes, found to affect the device operation, are discussed here: additional gain due to secondary scintillation; mixtures with enhanced ionization efficiency; improvement of pulse-height resolution due to avalanche confinement in the GEM holes; avalanche extension outside the GEM holes; gain limitation due to ion feedback and charging-up of GEM electrodes; photoelectron backscattering

  16. The use of concomitant elements to evaluate an Ar-N2 mixed-gas plasma by electrothermal vaporization inductively coupled plasma orthogonal time-of-flight mass spectrometry

    International Nuclear Information System (INIS)

    The performance of an Ar-N2 mixed-gas plasma was compared to an Ar plasma using electrothermal vaporization as a sample introduction source to an inductively coupled plasma orthogonal time-of-flight mass spectrometer. The effect of sample matrices NaNO3 and Pd(NO3)2 on a multi-element solution was investigated in mass amounts ranging from 0.1 to 5 μg of the metal matrix (e.g., Na and Pd). Addition of 2% N2 to the outer plasma gas of an Ar plasma reduced signal suppressions observed in the presence of high concentrations of Na and Pd at the expense of a large reduction in analyte sensitivity (ca. 83%). Signal profiles indicate that suppression may be caused, in part, by space charge effects that are dependent on the ion density of analyte and matrix ions. By reducing the magnitude of the signal from the N2-free plasma by repositioning the torch away from the sampling cone, comparable immunity to excess matrix was observed when compared to a plasma with N2 included in the outer plasma gas

  17. The use of concomitant elements to evaluate an Ar-N{sub 2} mixed-gas plasma by electrothermal vaporization inductively coupled plasma orthogonal time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Balsanek, William J. [Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712 (United States); Ertas, Gulay [Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712 (United States); Holcombe, James A. [Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712 (United States)]. E-mail: holcombe@mail.utexas.edu

    2006-06-15

    The performance of an Ar-N{sub 2} mixed-gas plasma was compared to an Ar plasma using electrothermal vaporization as a sample introduction source to an inductively coupled plasma orthogonal time-of-flight mass spectrometer. The effect of sample matrices NaNO{sub 3} and Pd(NO{sub 3}){sub 2} on a multi-element solution was investigated in mass amounts ranging from 0.1 to 5 {mu}g of the metal matrix (e.g., Na and Pd). Addition of 2% N{sub 2} to the outer plasma gas of an Ar plasma reduced signal suppressions observed in the presence of high concentrations of Na and Pd at the expense of a large reduction in analyte sensitivity (ca. 83%). Signal profiles indicate that suppression may be caused, in part, by space charge effects that are dependent on the ion density of analyte and matrix ions. By reducing the magnitude of the signal from the N{sub 2}-free plasma by repositioning the torch away from the sampling cone, comparable immunity to excess matrix was observed when compared to a plasma with N{sub 2} included in the outer plasma gas.

  18. Direct comparative study on the energy level alignments in unoccupied/occupied states of organic semiconductor/electrode interface by constructing in-situ photoemission spectroscopy and Ar gas cluster ion beam sputtering integrated analysis system

    International Nuclear Information System (INIS)

    Through the installation of electron gun and photon detector, an in-situ photoemission and damage-free sputtering integrated analysis system is completely constructed. Therefore, this system enables to accurately characterize the energy level alignments including unoccupied/occupied molecular orbital (LUMO/HOMO) levels at interface region of organic semiconductor/electrode according to depth position. Based on Ultraviolet Photoemission Spectroscopy (UPS), Inverse Photoemission Spectroscopy (IPES), and reflective electron energy loss spectroscopy, the occupied/unoccupied state of in-situ deposited Tris[4-(carbazol-9-yl)phenyl]amine (TCTA) organic semiconductors on Au (ELUMO: 2.51 eV and EHOMO: 1.35 eV) and Ti (ELUMO: 2.19 eV and EHOMO: 1.69 eV) electrodes are investigated, and the variation of energy level alignments according to work function of electrode (Au: 4.81 eV and Ti: 4.19 eV) is clearly verified. Subsequently, under the same analysis condition, the unoccupied/occupied states at bulk region of TCTA/Au structures are characterized using different Ar gas cluster ion beam (Ar GCIB) and Ar ion sputtering processes, respectively. While the Ar ion sputtering process critically distorts both occupied and unoccupied states in UPS/IPES spectra, the Ar GCIB sputtering process does not give rise to damage on them. Therefore, we clearly confirm that the in-situ photoemission spectroscopy in combination with Ar GCIB sputtering allows of investigating accurate energy level alignments at bulk/interface region as well as surface region of organic semiconductor/electrode structure.

  19. Modification of stearic acid in Ar and Ar-O2 pulsed DC discharge

    Directory of Open Access Journals (Sweden)

    Euclides Alexandre Bernardelli

    2011-12-01

    Full Text Available Stearic acid (CH3(CH216COOH was treated with Ar and Ar-O2 (10% pulsed DC discharges created by a cathode-anode confined system to elucidate the role of oxygen in plasma cleaning. The treatment time (5 to 120 minutes and plasma gas mixture (Ar and Ar-O2 were varied, and the results showed that the mass variation of stearic acid after Ar-O2 plasma exposure was greater than that of pure Ar plasma treatment. Thus, compared to Ar*, active oxygen species (O and O2, in all states enhance the etching process, regardless of their concentration. During the treatments, a liquid phase developed at the melting temperature of stearic acid, and differential thermal analyses showed that the formation of a liquid phase was associated with the breakage of bonds due to treatment with an Ar or Ar-O2 plasma. After treatment with Ar and Ar-O2 plasmas, the sample surface was significantly modified, especially when Ar-O2 was utilized. The role of oxygen in the treatment process is to break carbonaceous chains by forming oxidized products and/or to act as a barrier again ramification, which accelerates the etching of stearic acid.

  20. Atmospheric pressure plasma produced inside a closed package by a dielectric barrier discharge in Ar/CO2 for bacterial inactivation of biological samples

    DEFF Research Database (Denmark)

    Chiper, Alina Silvia; Chen, Weifeng; Mejlholm, Ole;

    2011-01-01

    The generation and evaluation of a dielectric barrier discharge produced inside a closed package made of a commercially available packaging film and filled with gas mixtures of Ar/CO2 at atmospheric pressure is reported. The discharge parameters were analysed by electrical measurements and optical...... emission spectroscopy in two modes of operation: trapped gas atmosphere and flowing gas atmosphere. Gas temperature was estimated using the OH(A–X) emission spectrum and the rotational temperature reached a saturation level after a few minutes of plasma running. The rotational temperature was almost three...

  1. The improvement of mechanical properties of aluminum nitride and alumina by 1 keV Ar+ ion irradiation in reactive gas environment

    International Nuclear Information System (INIS)

    Ar ions with 1 keV energy was irradiated on aluminum nitride in an O2 environment to increase the bonding strength with Cu and also on alumina in an N2 environment to increase the bending strength. Cu(1,000 angstrom) films were deposited by ion-beam sputter on Ar+ irradiated/unirradiated AlN surfaces and the change of the bond strength was investigated by a scratch test. For the study of chemical structural change don the Ar+ irradiated AlN surface. Cu(50 angstrom) were deposited on an AlN substrate and XPS depth profile analysis was performed. Cu films deposited on Ar+ irradiated AlN under an O2 environment showed the bond strength of 30 Newton by a scratch test. On the basis of Cu3p, Al2p near core levels and O1s, N1s core level spectra, it was found that the improvement of bond strength of Cu films on the AlN surface resulted from the formation of intermediate layers such as copper oxide and aluminum oxynitride. The bending strength of polycrystalline alumina irradiated by Ar ions in an N2 environment was also increased

  2. The improvement of mechanical properties of aluminum nitride and alumina by 1 keV Ar{sup +} ion irradiation in reactive gas environment

    Energy Technology Data Exchange (ETDEWEB)

    Koh, S.K.; Son, Y.B.; Gam, J.S.; Kim, C.J.; Choi, W.K.; Jung, H.J. [Korea Inst. of Science and Technology, Seoul (Korea, Republic of). Div. of Ceramics

    1996-12-31

    Ar ions with 1 keV energy was irradiated on aluminum nitride in an O{sub 2} environment to increase the bonding strength with Cu and also on alumina in an N{sub 2} environment to increase the bending strength. Cu(1,000 {angstrom}) films were deposited by ion-beam sputter on Ar{sup +} irradiated/unirradiated AlN surfaces and the change of the bond strength was investigated by a scratch test. For the study of chemical structural change don the Ar{sup +} irradiated AlN surface. Cu(50{angstrom}) were deposited on an AlN substrate and XPS depth profile analysis was performed. Cu films deposited on Ar{sup +} irradiated AlN under an O{sub 2} environment showed the bond strength of 30 Newton by a scratch test. On the basis of Cu3p, Al2p near core levels and O1s, N1s core level spectra, it was found that the improvement of bond strength of Cu films on the AlN surface resulted from the formation of intermediate layers such as copper oxide and aluminum oxynitride. The bending strength of polycrystalline alumina irradiated by Ar ions in an N{sub 2} environment was also increased.

  3. Ar + CO2 and He + CO2 Plasmas in ASTRAL

    Science.gov (United States)

    Boivin, R. F.; Gardner, A.; Munoz, J.; Kamar, O.; Loch, S.

    2007-11-01

    Spectroscopy study of the ASTRAL helicon plasma source running Ar + CO2 and He + CO2 gas mixes is presented. ASTRAL produces plasmas with the following parameters: ne = 10^10 - 10^13 cm-3, Te = 2 - 10 eV and Ti = 0.03 - 0.5 eV, B-field <= 1.3 kGauss, rf power <= 2 kWatt. A 0.33 m scanning monochromator is used for this study. Using Ar + CO2 gas mixes, very different plasmas are observed as the concentration of CO2 is changed. At low CO2 concentration, the bluish plasma is essentially atomic and argon transitions dominate the spectra. Weak C I and O I lines are present in the 750 - 1000 nm range. At higher CO2 concentration, the plasma becomes essentially molecular and is characterized by intense, white plasma columns. Here, spectra are filled with molecular bands (CO2, CO2^+, CO and CO^+). Limited molecular dissociative excitation processes associated with the production of C I and O I emission are also observed. On the other hand, He + CO2 plasmas are different. Here, rf matches are only possible at low CO2 concentration. Under these conditions, the spectra are characterized by strong C I and O I transitions with little or no molecular bands. Strong dissociative processes observed in these plasmas can be link to the high Te associated with He plasmas. An analysis of the spectra with possible scientific and industrial applications will be presented.

  4. Study of atmospheric pressure chemical vapor deposition by using a double discharge system for SiOx thin-film deposition with a HMDS/Ar/He/O2 gas mixture

    International Nuclear Information System (INIS)

    SiOx thin films were deposited at atmospheric pressure by using a double discharge system composed of a remote-type dielectric barrier discharge (DBD) formed above the substrate and a direct-type DBD formed by applying an AC power to the substrate with a gas mixture of hexamethyldisilazane (HMDS)/O2/He/Ar. Instead of using a single DBD, the use of the double discharge system not only showed higher SiOx thin film deposition rates but also produced fewer impurities in the deposited SiOx thin film. The improvement was partially related to the increased gas dissociation near the substrate through the direct-type DBD and to the remote-type DBD. A 7-kV, 30-kHz AC voltage was applied to the remote-type DBD and a 5-kV, 20-kHz AC voltage was applied to the direct-type DBD, with a gas mixture of HMDS (400 sccm)/O2 (20 slm)/He (5 slm)/Ar (3 slm). As a result, a SiOx deposition rate of 58.29 nm/scan could be obtained while moving the substrate at a speed of 0.25 meter/min.

  5. Effect of Different Filling Materials in Anammox Bacteria Enrichment

    Directory of Open Access Journals (Sweden)

    Dilek ÖZGÜN

    2012-12-01

    Full Text Available Purpose: Anaerobic ammonium oxidation (Anammox is a process that ammonium as electron donor is oxidized to nitrogen gas using nitrite as electron acceptor. Compared to conventional nitrification-denitrification processes, this process is used less oxygen and no organic material (methanol, glucose. However, the slow growth rate of Anammox bacteria (11-30 days is disadvantages. Therefore, batch reactors have been carried out in these bacteria enrichment. In this study continuously operated upflow anaerobic sludge reactor (UASB using different filling materials disposing of sensitive and slow-growing Anammox bacteria out of the system is purposed. Design and Methods: System is operated up-flow column reactor at 2 days hydraulic retention time (HRT in 45 days. In this study, ceramic stones and Linpor filling material are used. Using synthetic wastewater containing ammonium and nitrite, Ar/CO2 anaerobic conditions (95/5% supplied with gas. System is operated at a temperature 253 C in UASB. Temperature, pH, ammonia-nitrogen and nitrite nitrogen are measured. Results: Both filling material reactors are operated in 45 days. Ceramic stones filling reactor is observed quickly reaches 90% were used reactor ammonium removal. The ammonium nitrogen removal was slower in Linpor filling materials reactor. Nitrite removal is reached up to 90% in both the reactor. When compared to the stoichiometric equation in Linpor was composed of large amounts of nitrate. At the end of 25 days the results were similar to ceramic stone filling reactor with Linpor filling material reactors. Conclusions and Original Value: Anammox process as from nitrogen removal processes was discovered in 1995. Anammox bacteria that make up this process due to very low growth rates of microbial bacteria in the system must be kept in the system. Most of the studies in the literature, these bacteria enrichment stage is started instead of a continuous batch reactor system. In this study

  6. Capillary filling in closed end nanochannels.

    Science.gov (United States)

    Phan, Vinh Nguyen; Nguyen, Nam-Trung; Yang, Chun; Joseph, Pierre; Djeghlaf, Lyes; Bourrier, David; Gue, Anne-Marie

    2010-08-17

    We investigated the interactions between liquid, gas, and solid phases in the capillary filling process of closed-end nanochannels. This paper presents theoretical models without and with absorption and diffusion of gas molecules in the liquid. Capillary filling experiments were carried out in closed-end silicon nanochannels with different lengths. The theoretical and measured characteristics of filling length versus time are compared. The results show that the filling process consists of two stages. The first stage resembles the capillary filling process in an open-end nanochannel. However, a remarkable discrepancy between the experimental results and the theory without gas absorption is observed in the second stage. A closer investigation of the second stage reveals that the dissolution of gas in the liquid is important and can be explained by the model with gas absorption and diffusion. PMID:20695566

  7. Effects of shock pressure on 40Ar-39Ar radiometric age determinations

    International Nuclear Information System (INIS)

    The relation of shock to the drop in the 40*Ar/39*Ar ratio seen at high release temperatures in some neutron-irradiated lunar samples is investigated through measurements of the 40*Ar/39*Ar ratio in gas samples released by stepwise heating of rock samples previously subjected to shock, either in the laboratory or in nature. Explosives were used to shock solid pieces and powder of a basalt from a diabase dike in Liberia to calculated pressures of 65, 150 and 270 kbar. These, an unshocked sample of the powder, two naturally shocked samples from the Brent impact crater in Canada, one unshocked sample from near the crater, and appropriate monitors were irradiated. Ar from stepwise heating was analyzed. The unshocked basalt shows a good 40*Ar/39*Ar plateau at age 198 +-9 m.y. in agreement with a previous result of 186 +- 2 m.y. The shocked samples contain varying amounts of implanted atmospheric Ar, the isotopes of which have experienced mass fractionation. This effect is small enough in four samples so that the linearity of their graphs of 39*Ar/40Ar vs 36Ar/40Ar is evidence of a plateau. The ages of these samples are then 201 +- 10, 205 +- 12 and 201 +-9 m.y. It appears that the shock has had little effect on the 40Ar-39Ar age spectrum, although the release patterns of the 39*Ar are shifted downward by the order of 2000C. Shock implantation of Ar was at lower shock pressure, in the presence of less Ar, and into a less porous material than previously demonstrated. The Brent Crater samples do not all show good plateaus, but do indicate an age of 420 m.y. for the crater event and 795 +- 24 m.y. for the rock formation, in agreement with previous results. None of the 40*Ar/39*Ar profiles shows a drop at high temperature, but a possible role of shock implantation of Ar is indicated in the production of this effect. Further experiments are suggested. (author)

  8. Coupled cluster calculations of mean excitation energies of the noble gas atoms He, Ne and Ar and of the H2 molecule

    DEFF Research Database (Denmark)

    Sauer, Stephan P. A.; Haq, Inam U.; Sabin, John R.;

    2013-01-01

    Using an asymmetric-Lanczos-chain algorithm for the calculation of the coupled cluster linear response functions at the CCSD and CC2 levels of approximation, we have calculated the mean excitation energies of the noble gases He, Ne and Ar, and of the hydrogen molecule H2. Convergence with respect...... for the mean excitation energy of these two systems within the Bethe theory for the chosen basis set and, in the case of H2, at the experimental equilibrium geometry....

  9. Lipon thin films grown by plasma-enhanced metalorganic chemical vapor deposition in a N{sub 2}-H{sub 2}-Ar gas mixture

    Energy Technology Data Exchange (ETDEWEB)

    Meda, Lamartine, E-mail: LMeda@xula.edu [Department of Chemistry, Xavier University of Louisiana, 1 Drexel Drive, New Orleans, LA, 70125 (United States); Maxie, Eleston E. [Excellatron Solid State LLC, 263 Decatur Street, Atlanta, GA 30312 (United States)

    2012-01-01

    Lithium phosphorus oxynitride (Lipon) thin films have been deposited by a plasma-enhanced metalorganic chemical vapor deposition method. Lipon thin films were deposited on approximately 0.2 {mu}m thick Au-coated alumina substrates in a N{sub 2}-H{sub 2}-Ar plasma at 13.56 MHz, a power of 150 W, and at 180 Degree-Sign C using triethyl phosphate [(CH{sub 2}CH{sub 3}){sub 3}PO{sub 4}] and lithium tert-butoxide [(LiOC(CH{sub 3}){sub 3}] precursors. Lipon growth rates ranged from 10 to 42 nm/min and thicknesses varied from 1 to 2.5 {mu}m. X-ray powder diffraction showed that the films were amorphous, and X-ray photoelectron spectroscopy (XPS) revealed approximately 4 at.% N in the films. The ionic conductivity of Lipon was measured by electrochemical impedance spectroscopy to be approximately 1.02 {mu}S/cm, which is consistent with the ionic conductivity of Lipon deposited by radio frequency magnetron sputtering of Li{sub 3}PO{sub 4} targets in either mixed Ar-N{sub 2} or pure N{sub 2} atmosphere. Attempts to deposit Lipon in a N{sub 2}-O{sub 2}-Ar plasma resulted in the growth of Li{sub 3}PO{sub 4} thin films. The XPS analysis shows no C and N atom peaks. Due to the high impedance of these films, reliable conductivity measurements could not be obtained for films grown in N{sub 2}-O{sub 2}-Ar plasma.

  10. Dynamics of the spectral behaviour of an ultrashort laser pulse in an argon-gas-filled capillary discharge-preformed plasma channel

    Directory of Open Access Journals (Sweden)

    Sakai S.

    2013-11-01

    Full Text Available We have reported the argon plasma waveguide produced in an alumina (Al2O3 capillary discharge and used to guide ultrashort laser pulses at intensities of the order of 1016  W/cm2. A one-dimensional magnetohydrodynamic (MHD code was used to evaluate the average degree of ionization of Ar in the preformed plasma channel. The spectrum of the propagated laser pulse in the Ar plasma waveguide was not modified and was well reproduced by a particle-in-cell (PIC simulation under initial ion charge state of Ar3+ in the preformed plasma waveguide. The optimum timing for the laser pulse injection was around 150 ns after initiation of a discharge with a peak current of 200 A.

  11. Dynamics of the spectral behaviour of an ultrashort laser pulse in an argon-gas-filled capillary discharge-preformed plasma channel

    Science.gov (United States)

    Sakai, S.; Higashiguchi, T.; Yugami, N.; Bobrova, N.; Sentoku, Y.; Kodama, R.

    2013-11-01

    We have reported the argon plasma waveguide produced in an alumina (Al2O3) capillary discharge and used to guide ultrashort laser pulses at intensities of the order of 1016 W/cm2. A one-dimensional magnetohydrodynamic (MHD) code was used to evaluate the average degree of ionization of Ar in the preformed plasma channel. The spectrum of the propagated laser pulse in the Ar plasma waveguide was not modified and was well reproduced by a particle-in-cell (PIC) simulation under initial ion charge state of Ar3+ in the preformed plasma waveguide. The optimum timing for the laser pulse injection was around 150 ns after initiation of a discharge with a peak current of 200 A.

  12. Space-filling polyhedral sorbents

    Science.gov (United States)

    Haaland, Peter

    2016-06-21

    Solid sorbents, systems, and methods for pumping, storage, and purification of gases are disclosed. They derive from the dynamics of porous and free convection for specific gas/sorbent combinations and use space filling polyhedral microliths with facial aplanarities to produce sorbent arrays with interpenetrating interstitial manifolds of voids.

  13. Lipon thin films grown by plasma-enhanced metalorganic chemical vapor deposition in a N2–H2–Ar gas mixture

    International Nuclear Information System (INIS)

    Lithium phosphorus oxynitride (Lipon) thin films have been deposited by a plasma-enhanced metalorganic chemical vapor deposition method. Lipon thin films were deposited on approximately 0.2 μm thick Au-coated alumina substrates in a N2–H2–Ar plasma at 13.56 MHz, a power of 150 W, and at 180 °C using triethyl phosphate [(CH2CH3)3PO4] and lithium tert-butoxide [(LiOC(CH3)3] precursors. Lipon growth rates ranged from 10 to 42 nm/min and thicknesses varied from 1 to 2.5 μm. X-ray powder diffraction showed that the films were amorphous, and X-ray photoelectron spectroscopy (XPS) revealed approximately 4 at.% N in the films. The ionic conductivity of Lipon was measured by electrochemical impedance spectroscopy to be approximately 1.02 μS/cm, which is consistent with the ionic conductivity of Lipon deposited by radio frequency magnetron sputtering of Li3PO4 targets in either mixed Ar–N2 or pure N2 atmosphere. Attempts to deposit Lipon in a N2–O2–Ar plasma resulted in the growth of Li3PO4 thin films. The XPS analysis shows no C and N atom peaks. Due to the high impedance of these films, reliable conductivity measurements could not be obtained for films grown in N2–O2–Ar plasma.

  14. Theoretical Study of Decomposition Pathways for Rare-gas-containing Compounds HRgX (Rg = He, Ne, Ar, Kr; X = Cl, Br)

    Institute of Scientific and Technical Information of China (English)

    AI Chun-Zhi; SUN Ren-An; YAN Jie

    2005-01-01

    Eight species, HRgX (Rg = He, Ne, Ar, Kr; X = Cl, Br), are predicted to have bending transition states at B3PW91/AUG-cc-PVTZ level, leading to 2-body decomposition pathway like . The reaction path has been obtained with Intricate Reaction Coordinates (IRC) method on identical theoretical level. Additionally, the linear transition states of HArCl, HArBr, HKrCl and HKrBr were obtained at MP2/6-311++G (2d, 2p) level, resulting in 3-body dissociation channel as.

  15. A house with its own filling station

    International Nuclear Information System (INIS)

    This short article describes how a house in Erlinsbach, Switzerland was rebuilt and, at the same time, fitted with a new gas-fired heating system - and with its own natural gas filling station. The history behind this unusual project is discussed. The inclusion of a filling station in the project made it worthwhile for the gas utility to lay a connection from the gas mains to the house. The economic advantages for its builder, who sells such natural gas filling station equipment, are mentioned. The consumption of the natural gas used as motor fuel is measured and taxed separately. Equivalent fuel costs are now said by the owner to be already below today's petrol prices and will become even lower when the planned reduction of levies on such use of natural gas come into force

  16. Dating quartz: Ar/Ar analyses of coexisting muscovite and fluid inclusion - rich quartz from paleocene amorphic aureole

    International Nuclear Information System (INIS)

    We present Ar/Ar total fusion and step-heating data for coexisting muscovite and white quartz from the metamorphic aureole of the Lower Paleocene La Copiapina Pluton, 6 km south of Inca de Oro, III Region, Chile. The pluton intrudes the upper clastic sedimentary member of the Punta del Cobre Group (Upper Jurassic - Lower Cretaceous) and the calcareous sedimentary rocks of the Chanarcillo Group (Neocomian), and comprises fine to coarse grained pyroxene-hornblende-biotite quartz diorites and monzodiorites. Its emplacement was controlled on its north-western side by a subvertical NE-trending fault, along which were developed vertically banded skarns (skarn mylonite), suggesting syntectonic intrusion. Biotite K-Ar ages for the pluton fall in the range 61-63 Ma, relating it to a latest Cretaceous to Lowest Paleocene syn-compressional intrusive belt which is present in the area (Matthews and Cornejo, 2000). A metamorphic / metasomatic aureole is developed within the sandstones of the Punta del Cobre Group, on the extreme northern limit of the pluton. In this area, the sedimentary rocks have been replaced by quartz-sericite and quartz-muscovite assemblages, with minor hematite and tourmaline, and late supergene kaolinite and pyrophyllite. A coarse muscovite-quartz-tourmaline-hematite assemblage is developed in and around older (early Upper Cretaceous) andesitic dykes, in the form of replacement / fracture fill veins and replacement zones. Further from the contact with the pluton, fine-grained quartz-sericite rock with coarser muscovite-rich replacement veins represents the dominant lithology. Quartz in the coarse replacement rock is very rich in fluid inclusions. Primary inclusions are mainly of two coexisting types; bi-phase (liquid and gas bubble) and tri-phase (liquid, gas bubble and halite crystal), indicating that the quartz formed in the presence of a boiling fluid. Some inclusions also contain sylvite and occasional hematite daughter crystals. Secondary inclusions

  17. Indium-tin oxide thin films deposited at room temperature on glass and PET substrates: Optical and electrical properties variation with the H2–Ar sputtering gas mixture

    International Nuclear Information System (INIS)

    Highlights: • ITO deposition on glass and PET at room temperature by using H. • High transparency and low resistance is obtained by tuning the H. • The figure of merit for ITO films on PET becomes maximal for thickness near 100 nm. - Abstract: The optical and electrical properties of indium tin oxide (ITO) films deposited at room temperature on glass and polyethylene terephthalate (PET) substrates were investigated. A clear evolution of optical transparency and sheet resistance with the content of H2 in the gas mixture of H2 and Ar during magnetron sputtering deposition is observed. An optimized performance of the transparent conductive properties ITO films on PET was achieved for samples prepared using H2/(Ar + H2) ratio in the range of 0.3–0.6%. Moreover, flexible ITO-PET samples show a better transparent conductive figure of merit, ΦTC = T10/RS, than their glass counterparts. These results provide valuable insight into the room temperature fabrication and development of transparent conductive ITO-based flexible devices

  18. 39Ar-40Ar dating of mesosiderites: Evidence for major parent body disruption < 4 Ga ago

    International Nuclear Information System (INIS)

    39Ar-40Ar ages were measured on 17 samples of 14 different mesosiderites and indicate major degassing of Ar by one or more thermal events less than 4.0 Ga ago. Three samples gave release patterns of constant age, whereas the other samples typically showed 200-400 Ma increases in 39Ar-40Ar age with increasing gas extraction temperature. These stepwise releases indicate ages of ∼3.4-3.8 Ga; averaged ages for individual meteorites are 3.45-3.82 Ga. No substantial evidence exists in the temperature releases for 39Ar-40Ar ages older than 4.0 Ga, and the Ar ages appear to be in contradiction to 244Pu fission track ages previously reported for a few mesosiderites. We suggest that metal-silicate mixing occurred ∼4.4 Ga ago, but that a major collisional event disrupted the mesosiderite parent planet 500 degree C, and left them deeply buried to undergo slow cooling

  19. Phase diagram of two dimensional electron gas in a perpendicular magnetic field around Landau level filling factors ν = 1 and 3

    International Nuclear Information System (INIS)

    The measured melting curve Tm(ν) between the crystal and liquid phases is analyzed using thermodynamics to extract the change of magnetization ΔM as a function of the Landau level filling factor ν near ν = 1. An explanation of ΔM(ν)$ is proposed in terms of Skyrmions. Near ν = 3, a Wigner crystal is the most probable solid phase, experiments excluding Skyrmions. (author)

  20. Phase diagram of two-dimensional electron gas in a perpendicular magnetic field around Landau level filling factors {nu}=1 and 3

    Energy Technology Data Exchange (ETDEWEB)

    March, Norman H. [Abdus Salam International Center for Theoretical Physics, Trieste (Italy); Department of Physics, University of Antwerp, Antwerp (Belgium); Oxford University, Oxford (United Kingdom); Cabo, Alejandro [Abdus Salam International Center for Theoretical Physics, Trieste (Italy) and Grupo de Fisica Teorica, Instituto de Cibernetica, Matematica y Fisica, Havana (Cuba)]. E-mail: cabo@cidet.icmf.inf.cu; Claro, Francisco [Facultad de Fisica, Pontificia Universidad Catolica de Chile, Santiago de Chile (Chile)

    2006-01-09

    The measured melting curve T{sub m}({nu}) between the crystal and liquid phases is analyzed using thermodynamics to extract the change of magnetization {delta}M as a function of the Landau level filling factor {nu}, near {nu}=1. An explanation of {delta}M({nu}) is proposed in terms of skyrmions. Near {nu}=3, a Wigner crystal is the most probable solid phase, experiments excluding skyrmions.

  1. Tunable coherent soft X-ray source based on the generation of high-order harmonic of femtosecond laser radiation in gas-filled capillaries

    International Nuclear Information System (INIS)

    We have carried out experimental and theoretical investigations of a tunable coherent soft X-ray radiation source in the 30 – 52 nm wavelength range based on the generation of high-order harmonics of femtosecond laser radiation propagating in a dielectric xenon-filled capillary. The long path of laser pulse propagation through the capillary permits tuning the generated harmonic wavelengths to almost completely span the range under consideration. (interaction of radiation with matter)

  2. Contributions to the 37Ar background by research reactor operations

    International Nuclear Information System (INIS)

    Radioargon has been identified as a useful nuclide for verifying compliance with the Comprehensive Nuclear-Test-Ban Treaty. Use of 37Ar to identify a nuclear explosion requires quantification of contributions to the 37Ar background at a potential measurement site. A method of estimating 37Ar release activities using isotopes of radioxenon and radioargon has been developed in this paper. Numerical solutions to the system of equations describing air-activation in a reactor were used to determine ratios of release activities for 135Xe/133Xe, 133mXe/131mXe, and 37Ar /41Ar as function of irradiation time and off-gas residence time prior to measurement and release. Published radioactive noble gas effluent data for the High Flux Isotope Reactor, HFIR (ORNL) from the year 1996 to 2010 were compiled as a test data set to predict the 37Ar release on a yearly basis. An average 37Ar release rate of 1.86 x 1010 Bq per year was calculated. The estimated release rate was used as a source term for atmospheric transport to run a test case for 37Ar release over a typical HFIR operation cycle. Results showed that ground-level concentrations of 37Ar did not exceed the minimum detectable concentration for a 37Ar field measurement system beyond the immediate vicinity of the release point. (author)

  3. Hydrogen Filling Station

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, Robert F; Sabacky, Bruce; Anderson II, Everett B; Haberman, David; Al-Hassin, Mowafak; He, Xiaoming; Morriseau, Brian

    2010-02-24

    Hydrogen is an environmentally attractive transportation fuel that has the potential to displace fossil fuels. The Freedom CAR and Freedom FUEL initiatives emphasize the importance of hydrogen as a future transportation fuel. Presently, Las Vegas has one hydrogen fueling station powered by natural gas. However, the use of traditional sources of energy to produce hydrogen does not maximize the benefit. The hydrogen fueling station developed under this grant used electrolysis units and solar energy to produce hydrogen fuel. Water and electricity are furnished to the unit and the output is hydrogen and oxygen. Three vehicles were converted to utilize the hydrogen produced at the station. The vehicles were all equipped with different types of technologies. The vehicles were used in the day-to-day operation of the Las Vegas Valley Water District and monitoring was performed on efficiency, reliability and maintenance requirements. The research and demonstration utilized for the reconfiguration of these vehicles could lead to new technologies in vehicle development that could make hydrogen-fueled vehicles more cost effective, economical, efficient and more widely used. In order to advance the development of a hydrogen future in Southern Nevada, project partners recognized a need to bring various entities involved in hydrogen development and deployment together as a means of sharing knowledge and eliminating duplication of efforts. A road-mapping session was held in Las Vegas in June 2006. The Nevada State Energy Office, representatives from DOE, DOE contractors and LANL, NETL, NREL were present. Leadership from the National hydrogen Association Board of Directors also attended. As a result of this session, a roadmap for hydrogen development was created. This roadmap has the ability to become a tool for use by other road-mapping efforts in the hydrogen community. It could also become a standard template for other states or even countries to approach planning for a hydrogen

  4. Hydrogen Filling Station

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, Robert F; Sabacky, Bruce; Anderson II, Everett B; Haberman, David; Al-Hassin, Mowafak; He, Xiaoming; Morriseau, Brian

    2010-02-24

    Hydrogen is an environmentally attractive transportation fuel that has the potential to displace fossil fuels. The Freedom CAR and Freedom FUEL initiatives emphasize the importance of hydrogen as a future transportation fuel. Presently, Las Vegas has one hydrogen fueling station powered by natural gas. However, the use of traditional sources of energy to produce hydrogen does not maximize the benefit. The hydrogen fueling station developed under this grant used electrolysis units and solar energy to produce hydrogen fuel. Water and electricity are furnished to the unit and the output is hydrogen and oxygen. Three vehicles were converted to utilize the hydrogen produced at the station. The vehicles were all equipped with different types of technologies. The vehicles were used in the day-to-day operation of the Las Vegas Valley Water District and monitoring was performed on efficiency, reliability and maintenance requirements. The research and demonstration utilized for the reconfiguration of these vehicles could lead to new technologies in vehicle development that could make hydrogen-fueled vehicles more cost effective, economical, efficient and more widely used. In order to advance the development of a hydrogen future in Southern Nevada, project partners recognized a need to bring various entities involved in hydrogen development and deployment together as a means of sharing knowledge and eliminating duplication of efforts. A road-mapping session was held in Las Vegas in June 2006. The Nevada State Energy Office, representatives from DOE, DOE contractors and LANL, NETL, NREL were present. Leadership from the National hydrogen Association Board of Directors also attended. As a result of this session, a roadmap for hydrogen development was created. This roadmap has the ability to become a tool for use by other road-mapping efforts in the hydrogen community. It could also become a standard template for other states or even countries to approach planning for a hydrogen

  5. Tooth-Colored Fillings

    Science.gov (United States)

    ... past, teeth were filled with a mixture—or amalgam—of different metals. Today that is changing as more natural-looking and metal-free dental fillings are becoming the preferred approach. Dentists are ...

  6. Strong magnetism observed in carbon nanoparticles produced by the laser vaporization of a carbon pellet in hydrogen-containing Ar balance gas.

    Science.gov (United States)

    Asano, Hirohito; Muraki, Susumu; Endo, Hiroki; Bandow, Shunji; Iijima, Sumio

    2010-08-25

    Nanometer-scale carbon particles driven by the pulsed-laser vaporization of pelletized pure carbon powder at 1000 °C in a hydrogen-containing environment show anomalous magnetism like a superparamagnet, while the sample prepared in 100% of Ar does not show such magnetism. The observed magnetism was unchanged over months in the ambient. The structure of this nanomaterial resembles the foam of a laundry detergent and transmission electron microscopy indicates a clear corrugated line contrast. On the other hand, a sample without strong magnetism does not give such an image contrast. The x-ray diffraction pattern coincides with that of graphite and no other peak is detected. Thermogravimetry indicates that all samples completely burn out up to approx. 820 °C and no material remains after combustion, indicating that the sample does not contain impurity metals. Magnetization is easily saturated by ∼10,000 G at 280 K with no hysteresis, but the hysteresis appears at 4.2 K. This phenomenon is explained by introducing a crystalline anisotropy which restricts the motion of the magnetic moment and stabilizes the remnant magnetization at zero magnetic field. Magnitudes of the saturation magnetization are in the range of 1-5 emu G g(-1) at 4.2 K, which correspond to 0.002-0.01 Bohr magneton per carbon atom. This concentration may be increased by ten times or more, because only about 4-10% of particles have a magnetic domain in the present samples. PMID:21386499

  7. The state dependence of the interaction of metastable rare gas atoms Rg sup * (ms sup 3 P sub 2 , sup 3 P sub 0 ) (Rg=Ne, Ar, Kr, Xe) with ground state sodium atoms

    Energy Technology Data Exchange (ETDEWEB)

    Schohl, S.; Mueller, M.W.; Meijer, H.A.J.; Ruf, M.W.; Hotop, H. (Kaiserslautern Univ. (Germany, F.R.). Fachbereich Physik); Morgner, H. (Witten-Herdecke Univ., Witten (Germany, F.R.). Inst. fuer Experimentalphysik)

    1990-08-01

    Using crossed beams of metastable rare gas atoms Rg{sup *}(ms {sup 3}P{sub 2}, {sup 3}P{sub 0}) (Rg=Ne, Ar, Kr, Xe) and ground state sodium atoms Na(3s {sup 2}S{sub 1/2}), we have measured the energy spectra of electrons released in the respective Penning ionization processes at thermal collision energies. For Rg{sup *}({sup 3}P{sub 2})+Na(3s), the spectra are quite similar for the different rare gases, both in width and shape; they reflect attractive interactions in the entrance channel with well depths D{sub e}{sup *} (meV) decreasing slowly from Rg=Ne to Xe as follows: 676(18); 602(23); 565(26); 555(30). For Rg{sup *}({sup 3}P{sub 0})+Na(3 s), the spectra vary strongly with the rare gas, indicating a change in the character of the interaction from van der Waals type attraction (Ne) to chemical binding for Kr and Xe with well depths D{sub e}{sup *} (meV) of: 51(19); 107(25); 432(30); 530(50). These findings are explained through model calculations of the respective potential curves, in which the exchange and the spin orbit interaction in the excited rare gas and the molecular interaction between the two valence s-electrons in terms of suitably chosen singlet and triplet potentials are taken into account. These calculations also explain qualitatively the experimental finding that the ratios q{sub 2}/q{sub 0} of the ionization cross sections for Rg{sup *}({sup 3}P{sub 2})+Na and Rg{sup *}({sup 3}P{sub 0})+Na vary strongly with the rare gas from Ne to Xe as follows: 15.8(3.2); 2.6(4); 1.4(2); 1.6(4). (orig.).

  8. Raman-Free, Noble-Gas-Filled Photonic-Crystal Fiber Source for Ultrafast, Very Bright Twin-Beam Squeezed Vacuum.

    Science.gov (United States)

    Finger, Martin A; Iskhakov, Timur Sh; Joly, Nicolas Y; Chekhova, Maria V; Russell, Philip St J

    2015-10-01

    We report a novel source of twin beams based on modulational instability in high-pressure argon-filled hollow-core kagome-style photonic-crystal fiber. The source is Raman-free and manifests strong photon-number correlations for femtosecond pulses of squeezed vacuum with a record brightness of ∼2500 photons per mode. The ultra-broadband (∼50  THz) twin beams are frequency tunable and contain one spatial and less than 5 frequency modes. The presented source outperforms all previously reported squeezed-vacuum twin-beam sources in terms of brightness and low mode content. PMID:26551812

  9. Superdeformation of Ar hypernuclei

    Science.gov (United States)

    Isaka, Masahiro; Kimura, Masaaki; Hiyama, Emiko; Sagawa, Hiroyuki

    2015-10-01

    We investigate the differences in the Λ separation energies (S_Λ ) of the ground and superdeformed (SD) states in {}^{37}_Λ Ar, ^{39}_Λ Ar, and ^{41}_Λ Ar within the framework of antisymmetrized molecular dynamics (AMD). In this study, we find that the calculated S_Λ values in the SD states are much smaller than those in the ground states, unlike the result using the relativistic mean-field (RMF) calculation [B.-N. Lu et al., Phys. Rev. C, 89, 044307 (2014)]. One of the reasons for this difference between the present work and the RMF calculation is the difference in the density profile of the SD states in the core nuclei. We also find that the property of the Λ N odd-parity interaction affects the S_Λ trend between the ground and SD states.

  10. Practical reactor production of {sup 41}Ar from argon clathrate

    Energy Technology Data Exchange (ETDEWEB)

    Mercer, J.R. E-mail: jmercer@pharmacy.ualberta.ca; Duke, M.J.M.; McQuarrie, S.A

    2000-06-01

    The radionuclide {sup 41}Ar has many ideal properties as a gas flow tracer. However, the modest cross-section of {sup 40}Ar for thermal neutron activation makes preparation of suitable activities of {sup 41}Ar technically difficult particularly for low flux reactors. Argon can however be trapped in a molecular complex called a clathrate that can then be irradiated. We prepared argon clathrate and explored its irradiation and stability characteristics. Argon clathrate can be used to provide gigabecquerel quantities of {sup 41}Ar even with low power reactors.

  11. Study of Ar and Ar-CO2 microwave surfaguide discharges by optical spectroscopy

    Science.gov (United States)

    Silva, Tiago; Britun, Nikolay; Godfroid, Thomas; van der Mullen, Joost; Snyders, Rony

    2016-05-01

    A surfaguide microwave discharge operating at 2.45 GHz in Ar and Ar-CO2 mixtures is studied using diagnostics methods based on optical emission spectroscopy. The population densities of Ar metastable and resonant states of the lowest group of excited levels ( 1 s x ) are investigated for several experimental conditions using the self-absorption technique. It is found that the densities of these levels, ranging from 1017 to 1016 m-3 for the pure Ar case, are dependent on the discharge pressure and applied power. The electron temperature and electron density are calculated via the balances of creation/loss mechanisms of radiative and metastable levels. In the range of the studied experimental conditions (50-300 W of applied power and 0.5-6 Torr of gas pressure), the results have shown that lower values of electron temperature correspond to higher values of power and pressure in the discharge. Adding CO2 to the argon plasma results in a considerable decrease (about 3 orders of magnitude) of the Ar metastable atom density. The feasibility of using the ratio of two Ar emission line intensities to measure the electron temperature in CO2 discharges with small Ar admixtures is studied.

  12. Accurate and precise 40Ar/39Ar dating by high-resolution, multi-collection, mass spectrometry

    DEFF Research Database (Denmark)

    Storey, Michael; Rivera, Tiffany; Flude, Stephanie

    -Instruments multi-collector Noblesse noble gas mass spectrometer configured with a faraday detector and three ion-counting electron multipliers. The instrument has the capability to measure several noble gas isotopes simultaneously and to change measurement configurations instantaneously by the use of QUAD lenses......New generation, high resolution, multi-collector noble gas mass spectrometers equipped with ion-counting electron multipliers provide opportunities for improved accuracy and precision in 40Ar/39Ar dating. Here we report analytical protocols and age cross-calibration studies using a NU...... (zoom optics). The Noblesse offer several advantages over previous generation noble gas mass spectrometers and is particularly suited for single crystal 40Ar/39Ar dating because of: (i) improved source sensitivity (ii) ion-counting electron multipliers, which have much lower signal to noise ratios than...

  13. Supercontinuum generation and tunable ultrafast emission in the vacuum ultraviolet using noble-gas-filled hollow-core photonic crystal fiber

    CERN Document Server

    Ermolov, Alexey; Frosz, Michael H; Travers, John C; Russell, Philip St J

    2015-01-01

    We report on the generation of a three-octave supercontinuum extending from the vacuum ultraviolet (VUV) to the near-infrared, spanning at least 113 to 1000 nm (i.e., 11 to 1.2 eV), in He-filled hollow-core kagome-style photonic crystal fiber. The same system also permits generation of narrower-band VUV radiation tunable from 113 to 200 nm with efficiencies exceeding 1% and VUV pulse energies in excess of 50 nJ. Modeling confirms that the mechanism involves soliton self-compression to sub-femtosecond pulse durations, dispersive-wave emission and the plasma-induced soliton self-frequency blue-shift. The bandwidth of the generated VUV light, which modeling shows to be coherent, is sufficient to support 500 as single-cycle pulses.

  14. The thermal significance of potassium feldspar K-Ar ages inferred from 40Ar/39Ar age spectrum results

    International Nuclear Information System (INIS)

    40Ar/39Ar age spectrum analyses of three microcline separates from the Separation Point Batholith, northwest Nelson, New Zealand, which cooled slowly through the temperature zone of partial radiogenic 40Ar accumulation are characterized by a linear age increase over the first 65 percent of gas release with the lowest ages corresponding to the time that the samples cooled below about 1000C. The last 35 percent of 39Ar released from the microclines yields plateau ages which reflect the different bulk mineral ages, and correspond to cooling temperatures between about 130 to 1600C. Theoretical calculations confirm the likelihood of diffusion gradients in feldspars cooling at rates =0C-Ma-1. Diffusion parameters calculated from the 39Ar release yield an activation energy, E = 28.8 +- 1.9 kcal-mol-1, and a frequency factor/grain size parameter, D0/l2 = 5.6sub(-3.9)sup(+14) sec-1. This Arrhenius relationship corresponds to a closure temperature of 132 +- 130C which is very similar to the independently estimated temperature. From the observed diffusion compensation correlation, this D0/l2 implies an average diffusion half-width of about 3 μm, similar to the half-width of the perthite lamellae in the feldspars. The results are discussed. (author)

  15. ARS Biodiesel Research Initiatives

    Science.gov (United States)

    Biodiesel activities within ARS are concerned with the production, quality, and properties of this alternative fuel from agriculturally derived fats and oils. Currently, in the absence of tax incentives, biodiesel production when using refined fats and oils and conventional alkali transesterificati...

  16. ARS Culture Collection

    Science.gov (United States)

    The internationally recognized Agricultural Research Service (ARS) Culture Collection will be described to include the microorganisms maintained by the collection, preservation methods and worldwide distribution of cultures. The impact of the germplasm will be described to include discovery of the f...

  17. ``Smoking From The Same Pipe": Developement of an 40Ar/39Ar Datting Intercalibration PIpette System (Invited)

    Science.gov (United States)

    Turrin, B. D.; Swisher, C. C.; Deino, A.; Hemming, S. R.; Hodges, K.; Renne, P. R.

    2010-12-01

    The precision and accuracy of Ar isotope ratio measurements is one of the main limiting factors in the uncertainties of an 40Ar/39Ar age. Currently, it is relatively common to measure Ar isotopic ratios to a precision of 1-2‰ or better on an intralaboratory basis. This level of analytical precision equates to a comparable level of precision (1-3‰) in the calculated age, depending on the extent of atmospheric Ar contamination, importance of nucleogenic interference corrections, and other factors. However, it has become clear that improving the precision of mass spectrometry is not the only bottleneck towards improving the accuracy and precision of 40Ar/39Ar dating in general. Rather, the most urgent issue is interlaboratory reproducibility. This became obvious in a recent EARTHTIME initiative undertaken to intercalibrate two commonly used 40Ar/39Ar standards [the Fish Canyon sanidine (FCs) and the Alder Creek sanidine (ACs)]. This effort revealed variations amongst laboratories (at the 1-2% level), an order of magnitude greater than the internal analytical precisions. To address these issues, we have proposed (to NSF) to construct two identical pipette systems loaded to identical starting pressures and with identical isotopic compositions. One pipette system will travel between participating 40Ar/39Ar labs and the second system will not travel and serve as the “Master” system to test for any fractionation or undocumented depletion of the traveling pipette system. In order to ensure delivery of uniform amounts of homogenous gas, the pipette system will be computer-controlled with preprogrammed routines and lockouts to prevent compromising the reservoirs. The pipette systems will deliver three gas samples with different isotopic ratios at two different pressures/concentrations. One pipette bulb will be of atmospheric isotopic composition, and the other two pipette bulbs will have 40Ar*/39ArK ratios corresponding to co-irradiated ACs and FCs fixed by their

  18. Advantages and disadvantages associated with introducing an extra rarefied gas layer into a rotating microsystem filled with a liquid lubricant: First and second law analyses

    International Nuclear Information System (INIS)

    In the present study, the effects of rarefaction, viscous dissipation, aspect ratio, and accommodation coefficients on transport characteristics associated with a two-phase flow within a rotating microsystem are investigated. It is assumed that centrifugal acceleration due to rotation separates the mixture into two immiscible gas and liquid layers. The incompressible Navier–Stokes–Fourier (NSF) equations in the cylindrical reference frame are employed, while the effects of velocity slip and temperature jump phenomena for the gaseous phase are taken into account. Considering external heating influence and applying the classical thermal boundary conditions of Uniform Heat Flux and Constant Wall Temperature, three different thermal cases are constructed. Expressions for the velocity and temperature distributions of these thermal cases as well as the average entropy generation rate and the Bejan number pertained to the gas and liquid layers are presented. In addition, the criteria for evaluating the impact of the gas layer on shear and temperature reductions at the shaft and also irreversibility rise in the medium are discussed. -- Highlights: ► An immiscible gas–liquid flow in a shaft-housing micro-configuration is studied. ► The investigation includes both first and second law analyses of thermodynamics. ► Analytical solutions of the velocity and temperature distributions are obtained. ► These solutions are employed to carry out the associated second law analysis. ► The impact of the gas layer on overall behavior of the system is then discussed.

  19. 46 CFR 98.25-65 - Filling density.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Filling density. 98.25-65 Section 98.25-65 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL... § 98.25-65 Filling density. (a) The filling density, or the percent ratio of the liquefied gas that...

  20. Intermolecular polarizabilities in H{sub 2}-rare-gas mixtures (H{sub 2}–He, Ne, Ar, Kr, Xe): Insight from collisional isotropic spectral properties

    Energy Technology Data Exchange (ETDEWEB)

    Głaz, Waldemar, E-mail: glaz@kielich.amu.edu.pl; Bancewicz, Tadeusz [Nonlinear Optics Division, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland); Godet, Jean-Luc [Laboratoire de photonique d’Angers, Université d’Angers, 2 boulevard Lavoisier, 49045 Angers (France); Gustafsson, Magnus [Department of Chemistry and Molecular Biology, University of Gothenburg, SE 412 96 Gothenburg (Sweden); Maroulis, George; Haskopoulos, Anastasios [Department of Chemistry, University of Patras, GR-26500 Patras (Greece)

    2014-08-21

    The report presents results of theoretical and numerical analysis of the electrical properties related to the isotropic part of the polarizability induced by interactions within compounds built up of a hydrogen H{sub 2} molecule and a set of noble gas atoms, Rg, ranging from the least massive helium up to the heaviest xenon perturber. The Cartesian components of the collisional polarizabilities of the H{sub 2}–Rg systems are found by means of the quantum chemistry methods and their dependence on the intermolecular distance is determined. On the basis of these data, the spherical, symmetry adapted components of the trace polarizability are derived in order to provide data sets that are convenient for evaluating collisional spectral profiles of the isotropic polarized part of light scattered by the H{sub 2}–Rg mixtures. Three independent methods of numerical computing of the spectral intensities are applied at room temperature (295 K). The properties of the roto-translational profiles obtained are discussed in order to determine the role played by contributions corresponding to each of the symmetry adapted parts of the trace polarizability. By spreading the analysis over the collection of the H{sub 2}–Rg systems, evolution of the spectral properties with the growing masses of the supermolecular compounds can be observed.

  1. Magnetron sputter deposition of low-stress, carbon-containing cubic boron nitride films using Ar-N2-CH4 gas mixtures

    International Nuclear Information System (INIS)

    Cubic boron nitride (c-BN) films produced by PVD and plasma-assisted CVD techniques typically exhibit undesired high compressive stresses. One of the effective and feasible methods to reduce stress and hence improve film adhesion has been a controlled addition of a third element into the film during deposition. In the present study, BN films were grown on to silicon substrates using reactive magnetron sputtering with a hexagonal BN target. An auxiliary flow of methane was mixed into argon and nitrogen as the working gas. The deposition was conducted at various methane flow rates at 400 oC substrate temperature, 0.2 Pa total working pressure, and - 250 V r.f. substrate bias. The microstructure of the deposited films was then examined in dependence of the methane flow rate. With increasing methane flow rate from 0 to approx. 2.0 sccm, the fraction of the cubic BN phase in the deposited films decreased gradually down to approx. 75 vol.%, whereas the film stress was reduced much more rapidly and almost linearly in relation to the methane flow rate. At 2.1 sccm methane, the stress became approx. 3 times reduced. Owing to the significantly decreased film stress, adherent, micrometer thick, cubic-phase dominant films can be allowed to form on silicon substrate. The microstructure of the films will be illustrated through FTIR and XRR.

  2. Study of gas amplification and first Townsend coefficient in parallel plate avalanche counter (PPAC) filled with pure isobutene by using heavy ions

    International Nuclear Information System (INIS)

    In this study by analyzing the PPAC pulse height at low pressures of iso-C4H10 gas (0.5-8.2 Torr) the following results were obtained: First, we described the Townsend coefficient over 171-526 (V/cm.torr) by employing the Brunner method and using O3+ ions. The applicability of these data to the other heavy ions was confirmed by 131 MeV Ne4+ ions. Our data are good agreement with the present data as well. Second, fig.6 shows that at lower pressures, by selecting proper operation condition, one can keep the energy loss approx. = 3 times less and reduced electric field approx. = 3 times higher without loss of pulse height. This is due to irregular behavior of the pulse height and was explained with a simple model of gas amplification. (author)

  3. Ion-kinetic simulations of D-3He gas-filled inertial confinement fusion target implosions with moderate to large Knudsen number

    Science.gov (United States)

    Larroche, O.; Rinderknecht, H. G.; Rosenberg, M. J.; Hoffman, N. M.; Atzeni, S.; Petrasso, R. D.; Amendt, P. A.; Séguin, F. H.

    2016-01-01

    Experiments designed to investigate the transition to non-collisional behavior in D3He-gas inertial confinement fusion target implosions display increasingly large discrepancies with respect to simulations by standard hydrodynamics codes as the expected ion mean-free-paths λc increase with respect to the target radius R (i.e., when the Knudsen number NK=λc/R grows). To take properly into account large NK's, multi-ion-species Vlasov-Fokker-Planck computations of the inner gas in the capsules have been performed, for two different values of NK, one moderate and one large. The results, including nuclear yield, reactivity-weighted ion temperatures, nuclear emissivities, and surface brightness, have been compared with the experimental data and with the results of hydrodynamical simulations, some of which include an ad hoc modeling of kinetic effects. The experimental results are quite accurately rendered by the kinetic calculations in the smaller-NK case, much better than by the hydrodynamical calculations. The kinetic effects at play in this case are thus correctly understood. However, in the higher-NK case, the agreement is much worse. The remaining discrepancies are shown to arise from kinetic phenomena (e.g., inter-species diffusion) occurring at the gas-pusher interface, which should be investigated in the future work.

  4. Numerical simualtion of underground 37Ar transportation to the ground

    International Nuclear Information System (INIS)

    Monitoring radioactive gas 37Ar is an important technique for the On-Site Inspection(OSI) of the Comprehensive Nuclear Test Ban Treaty (CTBT) verification regime. In order to establish a theoretical model that can be used to calculate the appearing time and radioactivity of 37Ar which transports to the ground after a nuclear explosion, the rock media in the test area is assumed to be a homogeneous porous media, without consideration of gas absorption by and release from the rock media. The seepage model in the porous media is used to calculate 37Ar transportation. Computational results give the time 37Ar leaks to the ground and the variation of its radioactivity with time. And we can analyze and consider the computational results when we have developed OSI noble gas monitoring systems and evaluated their effectiveness. (authors)

  5. Ars Electronica tulekul / Rael Artel

    Index Scriptorium Estoniae

    Artel, Rael, 1980-

    2003-01-01

    6.-11. IX toimub Austrias Linzis "Ars Electronica" festival, mille teema on "Code - The Language of Our Time". Festivali kavast, osalejatest, ava-performance'ist "Europe - A Symphonic Vision", näitusest "Cyberarts 2003. Prix Ars Electronica"

  6. Efeitos do pneumoperitônio com ar e CO2 na gasometria de suínos Effects of CO2 and air pneumoperitoneum on blood gas changes in pigs

    Directory of Open Access Journals (Sweden)

    Silvio Luis da Silveira Lemos

    2003-10-01

    Full Text Available OBJETIVO: O pneumoperitônio produz várias alterações na fisiologia humana. Algumas destas alterações, como hipercapnia e acidose, dependem ou são agravadas com o uso de CO2, tendo maior repercussão em pacientes com problema cardio-respiratório. A necessidade de uma melhor alternativa para insuflação da cavidade; a observação de que as cirurgias abertas, assim como as laparoscópicas com suspensão mecânica, são realizadas na presença de Ar ambiente; e a escassez de trabalhos testando o Ar em substituição ao CO2 para insuflação da cavidade, foram motivos para a realização deste trabalho. MÉTODOS: Vinte (0 suínos anestesiados foram submetidos a pneumoperitônio com 1 hora de duração. Os animais foram distribuídos em 4 grupos de 5 animais: Grupo A1 - Pneumoperitônio de Ar a 10 mmHg; Grupo A - Pneumoperitônio de Ar a 16 mmHg; Grupo B1 - Pneumoperitônio de CO2 a 10 mmHg; Grupo B - Pneumoperitônio de CO2 a 16 mmHg. O pneumoperitônio foi realizado pela técnica aberta com trocater de Hasson. Através de um cateter venoso central colhe-se amostra de sangue para exame de gasometria em 3 momentos. RESULTADOS: A análise da gasometria venosa não revelou alterações significativas entre os grupos em relação a PaO2 e a saturação do O2. Nos Grupos A1, A e B1 não foram observadas alterações no equilíbrio ácido-básico. No Grupo B após uma hora de pneumoperitônio houve nítida tendência a hipercapnia e acidose. CONCLUSÃO: O ar, com a técnica aberta de pneumoperitônio foi uma opção segura para insuflação de cavidade em procedimentos laparoscópicos diagnósticos de suínos.PURPOSE: The pneumoperitoneum causes several physiological alterations in humans. Some of these alterations, as hypercapnia and acidosis, are dependent on the use of CO2 or aggravated by its use, and affects mainly the patients with cardiopulmonary problems. The need for a better alternative of cavity insufflation; the observation that open

  7. ARABIC LIGHT STEMMER (ARS

    Directory of Open Access Journals (Sweden)

    ASMA AL-OMARI

    2014-12-01

    Full Text Available Stemming is a main step used to process textual data. It is usually used in several types of applications such as: text mining, information retrieval (IR, and natural language processing (NLP. A major task in stemming is to standardize words; which can be achieved by reducing each word to its base (root or stem. Arabic stemming is not an easy task. Unlike other languages, Arabic language is a highly inflected language, since it uses many inflectional forms. Researchers are divided on the benefit of using stemming in fields of IR, NLP...etc., since in Arabic the morphological variants of a certain word are not always semantically related. The aim of this paper is to design and implement a new Arabic light stemmer (ARS which is not based on Arabic root patterns. Instead, it depends on well defined mathematical rules and several relations between letters. A series of tests were conducted on ARS stemmer to compare its effectiveness with the effectiveness of two other Arabic stemmers. Test shows clearly the effectiveness superiority of ARS compared to effectiveness of these two Arabic stemmers.

  8. Filling Tanks with Hydrazine

    Science.gov (United States)

    Krueger, K.

    2004-10-01

    At the Hydrazine workshop in 2002 in Noordwijk several presentations dealt with the filling of satellite tanks. I was a bit surprised about the amount of manpower that is needed for this work. But I saw the same during the filling of the SCA system tanks some years ago in Trauen/Germany. I want to present the work flow of filling RESUS Hydrazine tanks. This bladder tanks have a capacity of 64 litres and are similar to some of the satellite tanks. We fill this tanks 25 to 50 times a year. Although the specifications are not exactly the same as those for satellite tank filling, it might be interesting to see how this work can be done half-automatically, because handling with Hydrazine is not a nice job, and the faster it goes, the better.

  9. Investigating Diffusion and Entropy with Carbon Dioxide-Filled Balloons

    Science.gov (United States)

    Jadrich, James; Bruxvoort, Crystal

    2010-01-01

    Fill an ordinary latex balloon with helium gas and you know what to expect. Over the next day or two the volume will decrease noticeably as helium escapes from the balloon. So what happens when a latex balloon is filled with carbon dioxide gas? Surprisingly, carbon dioxide balloons deflate at rates as much as an order of magnitude faster than…

  10. Laser parametric instability experiments of a 3ω, 15 kJ, 6-ns laser pulse in gas-filled hohlraums at the Ligne d'Intégration Laser facility

    Energy Technology Data Exchange (ETDEWEB)

    Rousseaux, C.; Huser, G.; Loiseau, P.; Casanova, M.; Alozy, E.; Villette, B.; Wrobel, R. [Commissariat à l' Energie Atomique, DAM, DIF, F-91297 Arpajon (France); Henry, O.; Raffestin, D. [Commissariat à l' Energie Atomique, DAM, CESTA, F-33114 Le Barp (France)

    2015-02-15

    Experimental investigation of stimulated Raman (SRS) and Brillouin (SBS) scattering have been obtained at the Ligne-d'Intégration-Laser facility (LIL, CEA-Cesta, France). The parametric instabilities (LPI) are driven by firing four laser beamlets (one quad) into millimeter size, gas-filled hohlraum targets. A quad delivers energy on target of 15 kJ at 3ω in a 6-ns shaped laser pulse. The quad is focused by means of 3ω gratings and is optically smoothed with a kinoform phase plate and with smoothing by spectral dispersion-like 2 GHz and/or 14 GHz laser bandwidth. Open- and closed-geometry hohlraums have been used, all being filled with 1-atm, neo-pentane (C{sub 5}H{sub 12}) gas. For SRS and SBS studies, the light backscattered into the focusing optics is analyzed with spectral and time resolutions. Near-backscattered light at 3ω and transmitted light at 3ω are also monitored in the open geometry case. Depending on the target geometry (plasma length and hydrodynamic evolution of the plasma), it is shown that, at maximum laser intensity about 9 × 10{sup 14} W/cm{sup 2}, Raman reflectivity noticeably increases up to 30% in 4-mm long plasmas while SBS stays below 10%. Consequently, laser transmission through long plasmas drops to about 10% of incident energy. Adding 14 GHz bandwidth to the laser always reduces LPI reflectivities, although this reduction is not dramatic.

  11. High-resolution Auger spectroscopy on 79 MeV Ar5+, 89 MeV Ar6+, and 136 MeV Ar7+ ions after excitation by helium

    International Nuclear Information System (INIS)

    In this thesis the atomic structure of highly excited Ar6+ and Ar7+ ions was studied. For this 79 MeV Ar5+, 89 MeV Ar6+, and 136 MeV Ar7+ ions of a heavy ion accelerator were excited by a He gas target to autoionizing states and the Auger electrons emitted in the decay were measured in highly-resolving state. The spectra were taken under an observational angle of zero degree relative to the beam axis in order to minimize the kinematical broadening of the Auger lines. (orig./HSI)

  12. Spectroanalytical investigations on inductively coupled N2/Ar and Ar/Ar high frequency plasmas

    International Nuclear Information System (INIS)

    In order to improve the detection limits of trace elements in corrosion products of metallic materials, the inductively coupled plasma excitation source (ICP) was applied for spectroscopic analysis. Besides optimizing the working conditions for the mentioned materials, the fundamental research clearing the excitation processes in ICP was carried out. Basicly, two plasma systems were investigated: the nitrogen cooled N2/Ar- and pure Ar/Ar-plasma. The computed detection limits for 8 chosen elements are between 0.1 and 50 μg ml-1 in both plasmas. The advantage of ion lines was clearly present; in N2/Ar-plasma it was larger than in Ar/Ar-plasma. The excitation temperatures measured with help of ArI, FeI and ZnI lines rise with increasing power and decreasing distance from the induction coil. The distribution of Zn excitation temperature in N2/Ar-plasma as well as the measured N+2 rotational and CN vibrational temperatures indicate, that the toroidal structure of Ar/Ar-plasma is not analogue to the N2/Ar-plasma. The values of the various excitation temperatures (Ar, Fe, Zn) and the differences between the excitation, vibration, rotation and ionization temperatures (Tsub(i) > Tsub(n) = Tsub(vib) > Tsub(rot)) indicate an absence of thermal equilibrium in the concerned system. (orig.)

  13. A Participatory Geographic Information System (PGIS Utilizing the GeoWeb 2.0: Filling the Gaps of the Marcellus Shale Natural Gas Industry

    Directory of Open Access Journals (Sweden)

    Drew Michanowicz

    2012-06-01

    Full Text Available The application of neocartography, specifically through the Web 2.0, is a new phase of participatory geographic information system (PGIS research. Neocartography includes the encouragement of non-expert participation through visual design (e.g., map layering, and knowledge discovery via the Web. To better understand the challenges from an increase in natural gas extraction in the Marcellus Shale region of the United States, a GeoWeb 2.0 platform titled FracTracker (FracTracker.org that relies upon PGIS and neocartography was created and implemented in June 2010. FracTracker focuses on data-to-information translation to stimulate capacity building for a range of user types by leveraging the immense benefits of a spatial component. The main features of FracTracker are the ability to upload and download geospatial data as various file types, visualize data through thematic mapping and charting tools, and learn about and share drilling experiences. In less than 2 years, 2,440 registered users have effectively participated in creating 956 maps or „snapshots' using 399 available datasets. FracTracker demonstrates that participatory, interoperable GeoWebs can be utilized to help understand and localize related impacts of complex systems, such as the extractive energy industry.

  14. Characterization of Mg/Al butt joints welded by gas tungsten arc filling with Zn–29.5Al–0.5Ti filler metal

    International Nuclear Information System (INIS)

    The multivariate alloying design of a welding joint is used in the Mg to Al welding process. A Zn–29.5Al–0.5Ti alloy is added as filler metal in gas tungsten arc welding of Mg and Al alloy joint based on the analysis of Al and Mg alloy characteristics. The tensile strength, microstructure, and phase constitution of the weld seam are analyzed. The formation of brittle and hard Mg–Al intermetallic compounds is avoided because of the effects of Zn, Al, and Ti. The average tensile strength of the joint is 148 MPa. Al3Ti is first precipitated and functions as the nucleus of heterogeneous nucleation during solidification. Moreover, the precipitated Al–MgZn2 hypoeutectic phase exhibited a feather-like structure, which enhances the property of the Mg–Al dissimilar joint. - Highlights: • Mg alloy AZ31B and Al alloy 6061 are butt welded by fusion welding. • The effect of Ti in filler metal is investigated. • The formation of Mg–Al intermetallic compounds is avoided

  15. About Dental Amalgam Fillings

    Science.gov (United States)

    ... decay and then shapes the tooth cavity for placement of the amalgam filling. Next, under appropriate safety ... About FDA Contact FDA Browse by Product Area Product Areas back Food Drugs Medical Devices Radiation-Emitting ...

  16. Primary retention following nuclear recoil in β-decay: Proposed synthesis of a metastable rare gas oxide (38ArO4) from (38ClO4−) and the evolution of chemical bonding over the nuclear transmutation reaction path

    International Nuclear Information System (INIS)

    (d)]. - Highlights: • Mathematical model for the yield of primary retention after β-decay. • The nature of metastable chemical bonding in thermodynamically unstable compounds. • The changes in the nature of chemical bond upon nuclear transmutation. • Synthetic protocol of metastable rare gas oxides (ArO4) from a hot chemistry route

  17. Acoustic resonance spectroscopy (ARS): ARS300 operations manual, software version 2.01

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-07-25

    Acoustic Resonance Spectroscopy (ARS) is a nondestructive evaluation technology developed at the Los Alamos National Laboratory. The ARS technique is a fast, safe, and nonintrusive technique that is particularly useful when a large number of objects need to be tested. Any physical object, whether solid, hollow, or fluid filled, has many modes of vibration. These modes of vibration, commonly referred to as the natural resonant modes or resonant frequencies, are determined by the object`s shape, size, and physical properties, such as elastic moduli, speed of sound, and density. If the object is mechanically excited at frequencies corresponding to its characteristic natural vibrational modes, a resonance effect can be observed when small excitation energies produce large amplitude vibrations in the object. At other excitation frequencies, i.e., vibrational response of the object is minimal.

  18. H- Beam Stripping Loss at Background Partial Pressure of Ar

    Institute of Scientific and Technical Information of China (English)

    Hu Chundong; Wang Shaohu; Hu Liqun

    2005-01-01

    It has been observed that H- current could be improved by adding Ar to H2 plasma.But due to a slower pumping speed for Ar with the existing pumping scheme, the tank pressure will increase quickly during the length of a beam pulse. Since H- stripping loss depends on the tank pressure and gas species, part of the H- beam can be converted to H0 and then H0 can be converted into H+ with background H2 and Ar gas thickness. Therefore, the H- beam current,measured by a Faraday cup, situated at a distance L from GG (ground grid), will decrease because it will be converted into a H+ current. This gives a ratio of the Faraday cup net current to the H- beam current before stripping at background partial pressure of Ar.

  19. Development of optical imaging capillary plate gas detector

    International Nuclear Information System (INIS)

    A capillary plate (CP) gas detector has been developed as a hole-type micropattern gas detector for several applications in many fields as follows: X-ray crystal structure analysis, cosmic X-ray polarimetry, cold neutron imaging, medical imaging application called portal imaging, and cellular function analysis. The optical imaging CP gas detector has been successfully operated with a gas mixture of Ar + CF4. Gas gains of up to 104 can be achieved with the gas mixtures. Scintillation light simultaneously emitted during the development of electron avalanches can be observed using a photomultiplier tube (PMT) and a CCD camera coupled to lens optics. The energy resolutions obtained for the charge signal and the light signal were 22% and 24% for 10 keV X-rays, respectively. The emission spectrum of the Ar (90%) + CF4 (10%) gas mixture was measured using the grating spectrophotometer for the CP gas detector. We can obtain one broad continuum extending from 450 nm to 680 nm with the peak of 620 nm owing to the dissociating process of CF4 molecules. The presence of the near infrared Ar I atomic lines were also observed at the wavelength between 700 nm and 850 nm due to transitions between the atomics states of Ar (3p5 4p) and Ar (3p5 4s). Utilizing the visible and near-infrared emission from the Ar + CF4 gas mixture, we can observe the scintillation light from the CP gas detector using a typical CCD camera coupled to a conventional lens system. Although the event acquisition rate is restricted to approximately 10 Hz by the sequential speed of the CCD readout, the optical method is very simple and powerful. Moreover, the CCD camera can provide fine imaging due to the very large number of channels (up to 106) having a pixel size of as small as 6 μm x 6 μm. We are also currently developing a gaseous photomultiplier (PMT) with a bi-alkali photocathode filled with an Ar (90%) + CF4 (10%) gas mixture in collaboration with Hamamatsu Photonics K.K. The final goal is to develop a

  20. MULTI-KEV X-Ray Yields From High-Z Gas Targets Fielded At Omega

    International Nuclear Information System (INIS)

    The authors report on modeling of x-ray yield from gas-filled targets shot at the OMEGA laser facility. The OMEGA targets were 1.8 mm long, 1.95 mm in diameter Be cans filled with either a 50:50 Ar:Xe mixture, pure Ar, pure Kr or pure Xe at ∼ 1 atm. The OMEGA experiments heated the gas with 20 kJ of 3ω (∼ 350 nm) laser energy delivered in a 1 ns square pulse. the emitted x-ray flux was monitored with the x-ray diode based DANTE instruments in the sub-keV range. Two-dimensional x-ray images (for energies 3-5 keV) of the targets were recorded with gated x-ray detectors. The x-ray spectra were recorded with the HENWAY crystal spectrometer at OMEGA. Predictions are 2D r-z cylindrical with DCA NLTE atomic physics. Models generally: (1) underpredict the Xe L-shell yields; (2) overpredict the Ar K-shell yields; (3) correctly predict the Xe thermal yields; and (4) greatly underpredict the Ar thermal yields. However, there are spreads within the data, e.g. the DMX Ar K-shell yields are correctly predicted. The predicted thermal yields show strong angular dependence.

  1. Geochronology and thermochronology by the 40Ar/39Ar method

    International Nuclear Information System (INIS)

    This work is a response to the authors' belief that there is a need for a monograph on 40Ar/39Ar dating to provide concise knowledge concerning the application of this method to geological studies. They aim to provide a reasonably comprehensive but by no means exhaustive coverage of the principles and practices of 40Ar/39Ar dating, with emphasis on interpretation of results. In attempting to provide an overview of the current state of knowledge, they commonly cite examples from the available literature. They draw rather heavily upon their own work, because they feel comfortable with their own examples. (author)

  2. The radon gas at the context of legislation on the quality of internal air in buildings - the Portuguese experience; O gas radao no contexto da legislacao sobre a qualidade do ar interior em edificios - a experiencia portuguesa

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, Paulo G.A.N.; Pereira, Alcides J.S.C.; Neves, Luis J.P.F., E-mail: ppinto@dct.uc.p, E-mail: apereira@dct.uc.p, E-mail: luisneves@dct.uc.p [Universidade de Coimbra (Portugal). Dept. de Ciencias da Terra. Instituto do Mar

    2011-10-26

    Radon gas has been recognized as an important environmental risk factor, especially when found in high concentrations inside buildings, and is currently classified by the World Health Organization as a carcinogen type 1. In this context, there is legislation in Portugal since 2006 that sets limits to its concentration in indoor air. The aim of this work was to synthesize the existing legislation with focus on the sampling and analysis. Some statistical data about the measurements obtained in the Natural Radioactivity Laboratory, of the Department of Earth Sciences, of the University of Coimbra are presented, and discussed in the context of the National Energy Certification of Buildings System

  3. Experimental study of NO2 reduction in N2/Ar and O2/Ar mixtures by pulsed corona discharge.

    Science.gov (United States)

    Zhu, Xinbo; Zheng, Chenghang; Gao, Xiang; Shen, Xu; Wang, Zhihua; Luo, Zhongyang; Cen, Kefa

    2014-11-01

    Non-thermal plasma technology has been regarded as a promising alternative technology for NOx removal. The understanding of NO2 reduction characteristics is extremely important since NO2 reduction could lower the total NO oxidation rate in the plasma atmosphere. In this study, NO2 reduction was experimentally investigated using a non-thermal plasma reactor driven by a pulsed power supply for different simulated gas compositions and operating parameters. The NO2 reduction was promoted by increasing the specific energy density (SED), and the highest conversion rates were 33.7%, 42.1% and 25.7% for Ar, N2/Ar and O2/Ar, respectively. For a given SED, the NO2 conversion rate had the order N2/Ar>Ar>O2/Ar. The highest energy yield of 3.31g/kWh was obtained in N2/Ar plasma and decreased with increasing SED; the same trends were also found in the other two gas compositions. The conversion rate decreased with increasing initial NO2 concentration. Furthermore, the presence of N2 or O2 led to different reaction pathways for NO2 conversion due to the formation of different dominating reactive radicals. PMID:25458679

  4. Geological Dating by 40 Ar - 39 Ar method

    International Nuclear Information System (INIS)

    The isotope 40 K is radioactive, it decays to 40 Ar stable. The number of 40 Ar atoms produced from 40 K, permits to calculate the date of rocks and minerals. This dating technique is named 'Conventional K-Ar Dating Method'. The 40 Ar - 39 Ar dating method permits to calculate the age of rocks and minerals eliminating the limitation of the K-Ar method by calculating potassium and argon concentrations in a single measurement of the ratio of argon isotopes. In this work, the irradiation of the sample with fast neutrons in the nuclear reactor was established. 39 Ar is obtained from the induced reaction 39 K (n,p) 39 Ar. Thus the ration of 40 Ar -39 Ar allows to obtain the date of rocks and minerals. This ratio was measured in a mass spectrometer. If the measurement of argon concentration in the sample is carried out at different increasing temperature values, it is possible to get information of paleotemperatures. The number of atoms 39 Ar is a function of the number 39 K atoms, irradiation time, neutrons flux, its energy E and the capture cross section σ of 39 K. These parameters are calculate indirectly by obtaining the so called 'J value ' by using a standard mineral with known age (HD-BI y Biot-133), this mineral is irradiated together with the unknown age sample. The values of 'J' obtained are in the interval of 2.85 a 3.03 (x 10-3)J/h. Rocks from 'Tres Virgenes' were dated by the method described in this work, showing an agreement with previous values of different authors. The age of this rocks are from Cenozoico era, mainly in the miocene period. (Author)

  5. A comparative study of CF4/O2/Ar and C4F8/O2/Ar plasmas for dry etching applications

    International Nuclear Information System (INIS)

    The effect of the O2/Ar mixing ratio in CF4/O2/Ar and C4F8/O2/Ar inductively coupled plasmas with a 50% fluorocarbon gas content on plasma parameters and active species densities, which influence dry etching mechanisms, was analyzed. The investigation combined plasma diagnostics using Langmuir probes and zero-dimensional plasma modeling. It was found that, in both gas systems, the substitution of Ar for O2 results in a similar change in the ion energy flux but causes the opposite behavior for the F atom flux. The mechanisms of these phenomena are discussed with regards to plasma chemistry. - Highlights: • The goal was to conduct a comparative study of CF4/O2/Ar and C4F8/O2/Ar plasmas. • The focus was on the parameters directly influencing dry etching mechanisms. • Model-based analysis for neutral species was used in this paper

  6. 40Ar/39Ar age calibration against counted annuallayers

    DEFF Research Database (Denmark)

    Storey, Michael; Stecher, Ole

    2008-01-01

    The 40Ar/39Ar method, based on the decay of the naturally occurring radioactive isotope 40K, is capable of producing ages with precision better than ± 0.1 %. However, accuracy is limited to no better than 1 % mainly due to the relatively large uncertainty in the 40K decay constants. One approach...

  7. Phase-matched high-order harmonics by interaction of Ar atoms with high-repetition-rate low-energy femtosecond laser pulses

    Institute of Scientific and Technical Information of China (English)

    XIE; Xinhua; ZENG; Zhinan; LI; Ruxin; CHEN; Shu; LU; Haihe

    2004-01-01

    Phase-matched high-order harmonic generation in Ar gas-filled cell was investigated experimentally. We obtained phase-matched 27th order harmonic driven by a commercially available solid-state femtosecond laser system at 0.55 m J/pulse energy level and 1 kHz repetition rate. To our knowledge, this is the lowest driving laser energy used to obtain phase-matched 27th order harmonic in a static gas cell. High-order harmonic generation at different gas density was studied systematically. Spectral blueshift and broadening of high harmonics under different pressure were analyzed. We found that the source size and spatial distribution of high-order harmonics are quite different under the phase-matching condition from those of the phase-mismatching case.

  8. Study on high pressure plasma produced by ArF laser

    OpenAIRE

    Tsuda, Norio; Yamada, Jun

    2004-01-01

    When an ArF excimer laser beam was focused in a high pressure argon gas from 50 to 130 atm, the plasma development is observed by streak camera from side window of chamber. The high pressure ArF laser plasma develops symmetrically and the plasma produced by ArF excimer laser hardly develops as compared with the plasma produced by XeCl. The photon energy of ArF laser light is higher than the XeCl laser. The transmittance of ArF laser light was measured. Almost all the laser light is transmitte...

  9. High-Energy Ions Emitted from Ar Clusters Irradiated by Intense Femtosecond Laser Pulses

    Institute of Scientific and Technical Information of China (English)

    LI Zhong; LEI An-Le; NI Guo-Quan; XU Zhi-Zhan

    2000-01-01

    We have experimentally studied the energy spectra of Ar ions emitted from Ar clusters irradiated by intense femtosecond laser pulses. The Ar clusters were produced in the adiabatic expansion of Ar gas into vacuum at high backing pressures. The laser peak intensity was about 2×106 W/cm2 with a pulse duration of 45 fs. The maximum and the average energies of Ar ions are 0.2 MeV and 15kev at a backing pressure of 2. S MPa, respectively. They are almost independent of the backing pressures in the range of 0.6 to 4.5 MPa.

  10. Near- and sub-barrier fusion of 6He+40Ar

    International Nuclear Information System (INIS)

    A measurement of the fusion cross section for 6He + 40Ar near and below the Coulomb barrier has been performed using a 6He beam from the UND/Um radioactive beam facility. The 6He nucleus is thought to have a neutron skin surrounding a 6He core. If this is the case, then Coulomb polarization of the core relative to the halo might result in neutron flow along a neck, and therefore to a large enhancement of the sub-barrier fusion cross section. 6He nuclei, of incident energy 10.05 ± 0.44 MeV, were directed into a segmented ionization counter (MUSIC) filled with P10 at 40 torr. The 40Ar in the detector gas served also as the target nuclei. 6He energies in the 50-cm active length of the detector varied from 7.75 MeV down to 3.05 MeV. Calculations indicate that fusion events should be distinguishable from most non-fusion events on the basis of energy deposition patterns in the ten MUSIC detector segments. For some large-angle scattering events a more elaborate analysis involving detailed Monte Carlo simulation of the various reactions is necessary

  11. The 38Ar(p,d)37Ar reaction

    International Nuclear Information System (INIS)

    The 38Ar(p,d)37Ar reaction has been used to study the properties of the high-lying positive parity states in 37Ar. Angular distributions in the region thetasub(c.m.)=160-1320 have been analyzed using the DWBA code DWUCK to determine the spectroscopic properties of these states. The two lowest T=3/2 states have been identified at 4.98MeV (3/2+) and 6.65MeV (1/2+). The results are compared to recent shell-model calculations; their significance for the solar neutrino experiment is also discussed. (Auth.)

  12. 40Ar retention in the terrestrial planets.

    Science.gov (United States)

    Watson, E Bruce; Thomas, Jay B; Cherniak, Daniele J

    2007-09-20

    The solid Earth is widely believed to have lost its original gases through a combination of early catastrophic release and regulated output over geologic time. In principle, the abundance of 40Ar in the atmosphere represents the time-integrated loss of gases from the interior, thought to occur through partial melting in the mantle followed by melt ascent to the surface and gas exsolution. Here we present data that reveal two major difficulties with this simple magmatic degassing scenario--argon seems to be compatible in the major phases of the terrestrial planets, and argon diffusion in these phases is slow at upper-mantle conditions. These results challenge the common belief that the upper mantle is nearly degassed of 40Ar, and they call into question the suitability of 40Ar as a monitor of planetary degassing. An alternative to magmatism is needed to release argon to the atmosphere, with one possibility being hydration of oceanic lithosphere consisting of relatively argon-rich olivine and orthopyroxene. PMID:17882213

  13. 40Ar/39Ar dating and geochemistry of tholeiitic magmatism related to the early opening of the Central Atlantic rift

    International Nuclear Information System (INIS)

    Tholeiitic effusive and intrusive magnetism from Iberia, Morocco, Algeria and Mali, realted to the early opening of the Central Atlantic rift, was dated by the 40Ar/39Ar step-heating method. Four plateau ags, rangin from 203.7±2.7 to 197.1±1.8 Ma, were obtained on plagioclase from dykes from theTaoudenni area (Mali) and two lava flows from Morocco. The Messejana dyke (Iberia), which previously yielded discrepant conventional K-Ar dates, did not furnish any 40Ar/39Ar plateau dates. However, there is a clear inverse relationship between apparent age and K/Ca atio for gas fractions from a plagioclase separate (proportional to the alteration degree) which, combined with dates obtained on amphibole, biotite and pyroxene, allows us to determine an age of around 200 Ma for this body. These data, and those obtained on the Foum Zguid (Morocco) and the Ksi Ksou (Algeria) dykes, give evidence of a brief magmatic event (between 206 and 195 Ma ago) which affected a large area ca. 2500 km long. Trace-element modelling shows that most of these formations originated from a homogeneous, enriched, source material. Such a brief magmatic episode related to the opening of a continental rift is in agreement with findings in other magmatic provinces (e.g. the Deccan traps and the Red Sea rift, precisely dated by the 40Ar/39Ar method as well). (orig.)

  14. 40Ar-39Ar geochronology and thermochronology: principles and potential

    International Nuclear Information System (INIS)

    Geochronology based on radiogenic isotopes has become an invaluable tool in earth sciences. Several radioactive parent-daughter systems of varying half-lives such as Rb-Sr, Sm-Nd, K-Ar have been traditionally used by researchers for determining the timing of geological and planetary processes. 40Ar-39Ar dating, a variant of the K-Ar system, is a well-established and versatile method of determining the eruptive ages of volcanic rocks and the ∼150-500 deg C thermal histories of a variety of more slowly cooled igneous and metamorphic rocks. This technique has been the most popular tool for dating felsic and intermediate volcanic rocks. Recently several new areas of research have been explored, including total-fusion dating of mineral grains from volcanic and sedimentary samples, mapping of argon isotopic gradients in crystals, and selective dating of fabric-defining minerals in poly deformed specimens

  15. Mass spectrometric measurements in inductively coupled CF4/Ar plasmas

    International Nuclear Information System (INIS)

    Positive ion fluxes, mean ion energies and ion energy distribution functions in low pressure CF4/Ar plasmas have been measured. The experiments were conducted in a Gaseous Electronics Conference cell using an inductively coupled plasma device powered by a 13.56 MHz radiofrequency (rf) power source. The measurements were made at 200 and 300 W of input rf power and at 10, 20, 30 and 50 mTorr gas pressures for three gas mixtures: (i) 20% CF4 : 80% Ar, (ii) 50% CF4 : 50% Ar and (iii) 80% CF4 : 20% Ar. A Langmuir probe was also used to measure plasma parameters such as ne, ni+ and electron energy distribution functions (EEDF) which were subsequently used to reconcile the mass spectrometer data. CF3+ is the most dominant fluorocarbon ion product of the plasma, followed by CF2+ and CF+. Ar+ is also detected in significant amounts with its relative flux increasing with the increase in Ar content in the gas mixture. Significant amounts of etch products, SiFx+/COF+x (x = 0-3), of the quartz window were also detected. The fluorocarbon ions are produced by direct electron impact and by ion-molecule reactions between Ar+ and CF4 as well as between CF3+ and CF4. However, the concentrations of CF2+ and CF+ are much larger than that which can be possibly produced from these two processes. The available cross-section data suggest that the direct electron impact ionization of the fragment neutrals and negative ion production by electron attachment may be responsible for the increase in the concentrations of the minor ions. F- densities, estimated by using the measured EEDF and positive ion flux data and the available cross-section data, agree well with the published experimental data

  16. Etching characteristics and mechanisms of Mo thin films in Cl2/Ar and CF4/Ar inductively coupled plasmas

    Science.gov (United States)

    Lim, Nomin; Efremov, Alexander; Yeom, Geun Young; Choi, Bok-Gil; Kwon, Kwang-Ho

    2014-11-01

    The etching characteristics and mechanism of Mo thin films in Cl2/Ar and CF4/Ar inductively coupled plasmas under the same operating conditions (pressure, 6 mTorr; input power, 700 W; bias power, 200 W) were investigated. For both gas mixtures, an increase in the Ar fraction or gas pressure at a fixed gas mixing ratio was found to cause a non-monotonic change in the Mo etching rates. The X-ray photoelectron spectroscopy (XPS) diagnostics indicated contamination of the etched surfaces by reaction products. The Cl2/Ar and CF4/Ar plasma parameters were also investigated using a combination of a zero-dimensional plasma model and plasma diagnostics using Langmuir probes. An analysis of the etching kinetics with the model-predicted fluxes of the plasma active species suggests that: 1) the Mo etching process occurs in the transitional regime of the ion-assisted chemical reaction, and 2) the non-monotonic Mo etching rate is probably associated with opposing changes in the fluxes of the reactive neutral species and ion energy.

  17. Preparation of zeolite 4A filled polyurethaneurea membranes and their gas separation performance%4A沸石填充聚氨酯杂化膜的制备及气体分离性能

    Institute of Scientific and Technical Information of China (English)

    白云翔; 邹超; 张春芳; 顾瑾; 孙余凭

    2011-01-01

    两步法制备了4A沸石填充的端羟基聚丁二烯基聚氨酯膜HTPB-PU/4A,并研究了CO2、H2、O2、N2的气体透过性能.结果表明:沸石与膜的相容性较好,添加4A沸石后,膜的热稳定性明显提高,O2渗透性及O2/N2选择性显著改善;随沸石添加时间的增加,膜对各种气体体系的选择性先增加后减小,而渗透性则先增加后趋于稳定;随硬段含量的增加,气体渗透性均下降,CO2/N2、O2/N2、H2/N2的选择性先升后降;随沸石添加量的增加,O2渗透性一直上升,而O2/N2的选择性先上升后下降,最大选择性达到7.11.%Zeolite 4A-filled hydroxyl terminated polybutadiene (HTPB) -based polyurethaneurea (PU) membranes, HTPB-PU/4A, are prepared by a two-step polymerization process to investigate the permeability of CO2, H2,O2 and N2. The results show that zeolite 4A particles are compatible with the PU segments and the incorporation of the zeolite 4A particles can apparently improve the thermal stability, permeability of O2 and selectivity of O2/N2 of the membranes. With the adding time of zeolite 4A increasing,the selectivity of the various gas systems increases initially and then decreases, while the permeability increases initially and then levels off. Increasing the content of hard segment in HTPB-PU, the permeability of various gas system in this study all decrease. However,the selectivity of CO2/N2 O2/N2 ,H2/N2 increases initially and then decreases. As the amount of zeolite 4A increases, O2 permeability continuously increases while the selectivity of O2/N2 increases at first and descrease afterwards. The highest selectivity can reach 7. 11.

  18. Ars Poetica : [luuletused] / Mats Traat

    Index Scriptorium Estoniae

    Traat, Mats, 1936-

    2008-01-01

    Sisu: Ars poetica ; Veepeegel ; Kontrollõed ; Mandariiniriik ; Nikolai Siamashvili (1888-1911) ; Kolmekümne kolmas aasta ; Kiri linast 1966 ; Italmaz Nuriyev ; Rudolf Rimmelile mõeldes ; Gennadi Aigi

  19. Computational phase diagrams of noble gas hydrates under pressure

    Energy Technology Data Exchange (ETDEWEB)

    Teeratchanan, Pattanasak, E-mail: s1270872@sms.ed.ac.uk; Hermann, Andreas, E-mail: a.hermann@ed.ac.uk [Centre for Science at Extreme Conditions and SUPA, School of Physics and Astronomy, The University of Edinburgh, Edinburgh EH9 3FD (United Kingdom)

    2015-10-21

    We present results from a first-principles study on the stability of noble gas-water compounds in the pressure range 0-100 kbar. Filled-ice structures based on the host water networks ice-I{sub h}, ice-I{sub c}, ice-II, and C{sub 0} interacting with guest species He, Ne, and Ar are investigated, using density functional theory (DFT) with four different exchange-correlation functionals that include dispersion effects to various degrees: the non-local density-based optPBE-van der Waals (vdW) and rPW86-vdW2 functionals, the semi-empirical D2 atom pair correction, and the semi-local PBE functional. In the He-water system, the sequence of stable phases closely matches that seen in the hydrogen hydrates, a guest species of comparable size. In the Ne-water system, we predict a novel hydrate structure based on the C{sub 0} water network to be stable or at least competitive at relatively low pressure. In the Ar-water system, as expected, no filled-ice phases are stable; however, a partially occupied Ar-C{sub 0} hydrate structure is metastable with respect to the constituents. The ability of the different DFT functionals to describe the weak host-guest interactions is analysed and compared to coupled cluster results on gas phase systems.

  20. Benign gastric filling defect

    International Nuclear Information System (INIS)

    The gastric lesion is a common source of complaints to Orientals, however, evaluation of gastric symptoms and laboratory examination offer little specific aid in the diagnosis of gastric diseases. Thus roentgenography of gastrointestinal tract is one of the most reliable method for detail diagnosis. On double contract study of stomach, gastric filling defect is mostly caused by malignant gastric cancer, however, other benign lesions can cause similar pictures which can be successfully treated by surgery. 66 cases of benign causes of gastric filling defect were analyzed at this point of view, which was verified pathologically by endoscope or surgery during recent 7 years in Yensei University College of Medicine, Severance Hospital. The characteristic radiological picture of each disease was discussed for precise radiologic diagnosis. 1. Of total 66 cases, there were 52 cases of benign gastric tumor 10 cases of gastric varices, 5 cases of gastric bezoar, 5 cases of corrosive gastritis, 3 cases of granulomatous disease and one case of gastric hematoma. 2. The most frequent causes of benign tumors were adenomatous polyp (35/42) and the next was leiomyoma (4/42). Others were one of case of carcinoid, neurofibroma and cyst. 3. Characteristic of benign adenomatous polyp were relatively small in size, smooth surface and were observed that large size, benign polyp was frequently type IV lesion with a stalk. 4. Submucosal tumors such as leiomyoma needed differential diagnosis with polypoid malignant cancer. However, the characteristic points of differentiation was well circumscribed smooth margined filling defect without definite mucosal destruction on surface. 5. Gastric varices showed multiple lobulated filling defected especially on gastric fundus that changed its size and shape by respiration and posture of patients. Same varices lesions on esophagus and history of liver disease were helpful for easier diagnosis. 6. Gastric bezoar showed well defined movable mass

  1. Ar-39-Ar-40 Ages of Two Nakhlites, MIL03346 and Y000593: A Detailed Analysis

    Science.gov (United States)

    Park, Jisun; Garrison, Daniel; Bogard, Donald

    2007-01-01

    Radiometric dating of martian nakhlites by several techniques have given similar ages of approx.1.2-1.4 Ga [e.g. 1, 2]. Unlike the case with shergottites, where the presence of martian atmosphere and inherited radiogenic Ar-40 produce apparent Ar-39-Ar-40 ages older than other radiometric ages, Ar-Ar ages of nakhlites are similar to ages derived by other techniques. However, even in some nakhlites the presence of trapped martian Ar produces some uncertainty in the Ar-Ar age. We present here an analysis of such Ar-Ar ages from the MIL03346 and Y000593 nakhlites.

  2. REGISTRATION OF BIRDSFOOT TREFOIL GERMPLASM ARS-2622

    Science.gov (United States)

    ARS-2622 broadleafed birdsfoot trefoil (Lotus corniculatus L.) germplasm was released by the USDA-ARS in cooperation with the Missouri Agricultural Experiment Station in August 2002. The merit of ARS-2622 is that it is a rhizome producing population with a broad genetic base. ARS-2622 was developed ...

  3. Preparing for faster filling

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Following the programmed technical stop last week, operators focussed on preparing the machine for faster filling, which includes multibunch injection and a faster pre-cycle phase.   The LHC1 screen shot during the first multibunch injection operation. The LHC operational schedule incorporates a technical stop for preventive maintenance roughly every six weeks of stable operation, during which several interventions on the various machines are carried out. Last week these included the replacement of a faulty magnet in the SPS pre-accelerator, which required the subsequent re-setting of the system of particle extraction and transfer to the LHC. At the end of last week, all the machines were handed back for operation and work could start on accommodating all the changes made into the complex systems in order for normal operation to be resumed. These ‘recovery’ operations continued through the weekend and into this week. At the beginning of this week, operators succeeded in pro...

  4. Bulk-Fill Resin Composites

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Havndrup-Pedersen, Cæcilie; Honoré, Daniel;

    2015-01-01

    restorative procedure. The aim of this study, therefore, was to compare the depth of cure, polymerization contraction, and gap formation in bulk-fill resin composites with those of a conventional resin composite. To achieve this, the depth of cure was assessed in accordance with the International Organization...... for Standardization 4049 standard, and the polymerization contraction was determined using the bonded-disc method. The gap formation was measured at the dentin margin of Class II cavities. Five bulk-fill resin composites were investigated: two high-viscosity (Tetric EvoCeram Bulk Fill, SonicFill) and...... three low-viscosity (x-tra base, Venus Bulk Fill, SDR) materials. Compared with the conventional resin composite, the high-viscosity bulk-fill materials exhibited only a small increase (but significant for Tetric EvoCeram Bulk Fill) in depth of cure and polymerization contraction, whereas the low...

  5. Analysis list: AR [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available AR Blood,Breast,Prostate + hg19 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/AR.1.tsv http://dbar...chive.biosciencedbc.jp/kyushu-u/hg19/target/AR.5.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/tar...get/AR.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/AR.Blood.tsv,http://dbar...chive.biosciencedbc.jp/kyushu-u/hg19/colo/AR.Breast.tsv,http://dbarchive.biosc...iencedbc.jp/kyushu-u/hg19/colo/AR.Prostate.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/Blood.gml,http://dbar

  6. Analysis list: Ar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Ar Gonad,Kidney,Prostate + mm9 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/targe...t/Ar.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Ar.5.tsv http://dbarchive.biosciencedbc.jp/...kyushu-u/mm9/target/Ar.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Ar.Gonad.tsv,http://dbarchive.bioscience...dbc.jp/kyushu-u/mm9/colo/Ar.Kidney.tsv,http://dbarchive.bioscienced...bc.jp/kyushu-u/mm9/colo/Ar.Prostate.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Gonad.gml,http://dbarchive.bioscience

  7. Adsorption of Ar on a nonuniform MgO surface

    Science.gov (United States)

    Hinman, D. C.; Halsey, G. D.

    1976-01-01

    Data are presented for the adsorption of Ar and N2 on a strongly heterogeneous MgO surface at 84 K and for Ar at a range of temperatures between 130 and 250 K. The high-temperature data are analyzed according to a model which separates the contributions to the potential into bulk and surface terms, providing a method for the determination of the surface area from parameters characteristic of the bulk material. A solid-gas energy parameter and parameters indicating the strength of the impurity sites are also evaluated.

  8. "Ars Electronica 2009" / Raivo Kelomees

    Index Scriptorium Estoniae

    Kelomees, Raivo, 1960-

    2009-01-01

    30. "Ars Electronica" festival "Human Nature" ("Inimese loomus") Linzis. Osaka ülikooli professori Hiroshi Ishiguro mehaanilis-digitaalsest nukust. Hübriidkunsti kategoorias peapreemia saanud Eduardo Kaci inimtaimest. Konverentsidest. Näitusest "See this Sound", mis oli pühendatud helile kujutavas kunstis

  9. A note on filled groups

    OpenAIRE

    Hart, Sarah; Anabanti, Chimere

    2015-01-01

    Let $G$ be a finite group and $S$ a subset of $G$. Then $S$ is {\\em product-free} if $S \\cap SS = \\emptyset$, and $S$ {\\em fills} $G$ if $G^{\\ast} \\subseteq S \\cup SS$. A product-free set is locally maximal if it is not contained in a strictly larger product-free set. Street and Whitehead [J. Combin. Theory Ser. A \\textbf{17} (1974), 219--226] defined a group $G$ as {\\em filled} if every locally maximal product-free set in $G$ fills $G$. Street and Whitehead classified all abelian filled grou...

  10. Optical Emission Spectroscopic Studies of ICP Ar Plasma

    Institute of Scientific and Technical Information of China (English)

    QI Xuelian; REN Chunsheng; ZHANG Jian; MA Tengcai

    2007-01-01

    The ion line of 434.8 nm and atom line of 419.8 nm of Ar plasma produced by an inductively coupled plasma (ICP) were measured by optical emission spectroscopy and the influences from the working gas pressure, radio-frequency (RF) power and different positions in the discharge chamber on the line intensities were investigated in this study. It was found that the intensity of Ar atom line increased firstly and then saturated with the increase of the pressure. The line intensity of Ar+, on the other hand, reached a maximum value and then decreased along with the pressure. The intensity of the line in an RF discharge also demonstrated a jumping mode and a hysteresis phenomenon with the RF power. When the RF power increased to 400 W, the discharge jumped from the E-mode to the H-mode where the line intensity of Ar atom demonstrated a sudden increase, while the intensity of Ar+ ion only changed slightly. If the RF power decreased from a high value, e.g., 1000 W, the discharge would jump from the H-mode back to the E-mode at a power of 300 W. At this time the intensities of Ar and Ar+ lines would also decrease sharply. It was also noticed in this paper that the intensity of the ion line depended on the detective location in the chamber, namely at the bottom of the chamber the line was more intense than that in the middle of the chamber, but less intense than at the top, which is considered to be related to the capacitance coupling ability of the ICP plasma in different discharge areas.

  11. Effect of Ar/CH4 Mixture Ratio on Properties of Ag/C:H Nanocomposite Prepared by DC Sputtering

    OpenAIRE

    E. Mohsen Soltani; Ghorannevis, Z.; M. Shirazi

    2013-01-01

    Ag/C:H films were deposited by DC sputtering method on Si substrates with different Ar/CH4 gas mixture ratios. Effect of Ar/CH4 gas mixture ratios was investigated on optical and structural properties of Ag/C:H films by FTIR spectroscopy analysis, X-Ray diffractometry (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM), respectively. In order to evaluate the effect of gas flow ratio on the optical and structural properties of Ag/C:H films, Ar/CH4 gas ratio was changed...

  12. Oldest human footprints dated by Ar/Ar

    Science.gov (United States)

    Scaillet, Stéphane; Vita-Scaillet, Grazia; Guillou, Hervé

    2008-11-01

    Fossilized human trackways are extremely rare in the geologic record. These bear indirect but invaluable testimony of human/hominid locomotion in open air settings and can provide critical information on biomechanical changes relating to bipedalism evolution throughout the primitive human lineage. Among these, the "Devil's footsteps" represent one of the best preserved human footprints suite recovered so far in a Pleistocene volcanic ash of the Roccamonfina volcano (southern Italy). Until recently, the age of these footprints remained speculative and indirectly correlated with a loosely dated caldera-forming eruption that produced the Brown Leucitic Tuff. Despite extensive hydrothermal alteration of the pyroclastic deposit and variable contamination with excess 40Ar, detailed and selective 40Ar/ 39Ar laser probe analysis of single leucite crystals recovered from the ash deposit shows that the pyroclastic layer and the footprints are 345 ± 6 kyr old (1 σ), confirming for the first time that these are the oldest human trackways ever dated, and that they were presumably left by the modern human predecessor, Homo heidelbergensis, close to Climatic Termination IV.

  13. 用双天平称重法实现高精度低浓度混和气的制备%Preparing Gas Mixture of Low Concentration and High Accuracy by the Double Balance Weighing Method

    Institute of Scientific and Technical Information of China (English)

    韦冠一; Adolf.G(o)tz; 张子斌; 李雪松; H.Gerken

    2004-01-01

    The brief procedure of how to get a gas mixture of low concentration and high accuracy with the double balance weighing method was described. This method requires two balances of both different ranges and high resolutions, also tow sets of equipment for introducing Ar, Ne, Kr, Xe, and the Nitrogen for balance gas. Two sets of equipment were fulfilled according to the described procedure without any backflow of the component gases. The residual gas in the filling equipment was analyzed to correct the mass of the component gases filled into the mixture gas. By this way, the concentration of Kr and Xe in the preparing mixture gas, is about 0.1%, with the maximum uncertainty of about 0.1%.

  14. Spectroscopy Study of Ar + CO2 Plasmas in ASTRAL.

    Science.gov (United States)

    Munoz, Jorge; Boivin, Robert; Kamar, Ola; Loch, Stuart; Ballance, Connor

    2006-10-01

    A spectroscopy study of the ASTRAL (Auburn Steady sTate Research fAciLity) helicon plasma source running Ar + CO2 gas mix is presented. ASTRAL produces Ar plasmas: ne = 10^10 to 10^13 cm-3, Te = 2 to 10 eV and Ti = 0.03 to 0.5 eV. A series of 7 large coils produce an axial magnetic field up to 1.3 kGauss. A fractional helix antenna is used to introduce rf power up to 2 kWatt. A spectrometer which features a 0.33 m Criss-Cross monochromator and a CCD camera is used for this study. Very different plasmas are produced following the relative importance of CO2 in the gas mixture. At low CO2 concentration, the plasmas are similar to those obtained with pure Ar with weak CO2, CO2^+, CO and CO^+ bands. The usual blue plasma core associated with intense Ar II transitions is observed with however a significant white glow coming from the outer plasma regions. At higher CO2 concentration, the plasma becomes essentially molecular and can be described as an intense white plasma column. Molecular dissociative processes associated with the production of strong C and O atomic lines are observed under specific plasma conditions. The atomic spectral lines are compared with ADAS modeling results. This study indicates the possible advantages of using a helicon source to control the CO2 plasma chemistry for industrial applications.

  15. Study on Antigravity Mold Filling by Conservative Scalar Method

    Institute of Scientific and Technical Information of China (English)

    李日; 王友序; 杨根仓; 毛协民

    2003-01-01

    By SIMPLE method and Van-Leer scheme, a program on numerical simulation for 3D mold filling has been developed. The fluid flow field of gas and liquid is calculated in couples by a single phase N-S equation using SIMPLE method, and free surface control equation is handied by Van-Leer scheme. Then it is verified by an anti-gravity mold filling of thin wall plate. In order to demonstrate its ability to simulate 3D casting, an anti-gravity mould filling of a cube is computed by the program.

  16. The dynamic response of carbon fiber-filled polymer composites

    OpenAIRE

    Patterson B.; Orler E.B.; Furmanski J.; Rigg P.A.; Scharff R.J.; Stahl D.B.; Sheffield S.A.; Gustavsen R.L.; Dattelbaum D.M.; Coe J.D.

    2012-01-01

    The dynamic (shock) responses of two carbon fiber-filled polymer composites have been quantified using gas gun-driven plate impact experimentation. The first composite is a filament-wound, highly unidirectional carbon fiber-filled epoxy with a high degree of porosity. The second composite is a chopped carbon fiber- and graphite-filled phenolic resin with little-to-no porosity. Hugoniot data are presented for the carbon fiber-epoxy (CE) composite to 18.6 GPa in the through-thickness direction,...

  17. 40Ar-39Ar age of the Shergotty achondrite and implications for its post-shock thermal history

    International Nuclear Information System (INIS)

    Analyses of 40Ar-39Ar have been made on a whole rock sample and a maskelynite (feldspar) separate of the shocked Shergotty achondrite. The maskelynite gave a plateau age of 254 +- 10 Myr. The whole rock sample gave a complex release with apparent ages between 240 and 640 Myr. The slightly younger Rb-Sr isochron age of 165 Myr for Shergotty suggests that the maskelynite as well as the whole rock was incompletely degassed. Reasonable Ar diffusion characteristics for Shergotty for shock heating temperatures of 0C indicate D/a2 of 10-11 to 10-13sec-1. The time required to lose 95% of the 40Ar from the plagioclase would be approximately 103 to 104 yr. When this gas diffusion time is introduced into a thermal model of a cooling ejecta blanket of variable thickness, a post-shock cooling time of >= 103 yr and a burial depth of >= 300 m are indicated for Shergotty. These conclusions are not seriously affected by uncertainties in the thermal model. Most likely the shock event occurred approximately 165 Myr ago, but no earlier than 250 Myr ago, when the Shergotty parent object experienced a collision in the asteroid belt. As a result of that collision, feldspar was converted to maskelynite, the K-Ar and Rb-Sr ages were completely or nearly completely reset, and the Shergotty meteorite was heated to 0C and left to cool slowly inside the parent body. (author)

  18. Interaction of a H2O/Ar Plasma Jet with Nitrogen Atmosphere: Effect of the Method for Calculating Thermophysical Properties of the Gas Mixture on the flow field

    Czech Academy of Sciences Publication Activity Database

    Agon, N.; Vierendeels, J.; Hrabovský, Milan; Murphy, A.B.; Van Oost, G.

    2015-01-01

    Roč. 35, č. 2 (2015), s. 365-386. ISSN 0272-4324 R&D Projects: GA ČR(CZ) GA15-19444S Institutional support: RVO:61389021 Keywords : Thermal plasma * Computational fluid dynamics * Thermophysical properties * Mixing rules * Ionized gas mixtures Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.056, year: 2014 http://link.springer.com/article/10.1007%2Fs11090-014-9605-6

  19. Mechanics of filled carbon nanotubes

    KAUST Repository

    Monteiro, A.O.

    2014-04-01

    The benefits of filling carbon nanotubes (CNTs) with assorted molecular and crystalline substances have been investigated for the past two decades. Amongst the study of new structural phases, defects, chemical reactions and varied types of host-guest interactions, there is one fundamental characterisation aspect of these systems that continues to be overlooked: the mechanical behaviour of filled CNTs. In contrast to their empty counterparts, the mechanics of filled CNTs is a subject where reports appear far and apart, this despite being key to the application of these materials in technological devices. In the following paragraphs, we review the work that has been carried out up to the present on the mechanics of filled CNTs. The studies discussed range from experimental resonant frequency essays performed within electron microscopes to modelling, via molecular dynamics, of three-point bending of nanotubes filled with gases. (C) 2014 Elsevier B.V. All rights reserved.

  20. AR-39Ar-40 dating of basalts and rock breccias from Apollo 17 and the malvern achondrite

    Science.gov (United States)

    Kirsten, T.; Horn, P.

    1977-01-01

    The principles and the potential of the Ar-39/Ar-40 dating technique are illustrated by means of results obtained for 12 Apollo 17 rocks. Emphasis is given to methodical problems and the geological interpretation of lunar rock ages. Often it is ambigious to associate a given lunar breccia with a certain formation, or a formation with a basin. In addition, large-scale events on the Moon have not necessarily reset radiometric clocks completely. One rock fragment has a well-defined plateau age of 4.28 b.y., but the ages of two Apollo 17 breccias define an upper limit for the formation age of the Serenitatis basin at 4.05 b.y. Ages derived from five mare basalts indicate cessation of mare volcanism at Taurus-Littrow approximately 3.78 b.y. ago. Ca/Ar-37 exposure ages show that Camelot Crater was formed by an impact approximately 95 m.y. ago. After a short summary of the lunar timetable as it stands at the end of the Apollo program, we report about Ar-39/Ar-40 and rare gas studies on the Malvern meteorite. This achondrite resembles lunar highland breccias in texture as well as in rare-gas patterns. It was strongly annealed at some time between 3.4 and 3.8 b.y. ago. The results indicate that very similar processes have occurred on the Moon and on achondritic parent bodies at comparable times, leading to impact breccias with strikingly similar features, including the retention of rare-gas isotopes from various sources.

  1. AR DOC: Augmented reality documentaries

    DEFF Research Database (Denmark)

    Vistisen, Peter

    2014-01-01

    Augmented Reality Documentaries (AR DOC) er et ’lille’ Shareplay projekt (ansøgte midler <= 125.000 DKK), der af haft som sit formål at afprøve et unikt samarbejde omkring udforskningen af nye teknikker til augmented reality cross media løsninger, til at skabe engagerende publikumsformidling...... indenfor oplevelsesindustrien. Projektet har genereret ny viden omkring, hvordan fysisk og digital formidling kan understøttes via Augmented Reality som formidlingsformat....

  2. ARS - Helsinki - 2006 / Galina Balashova

    Index Scriptorium Estoniae

    Balashova, Galina

    2006-01-01

    Steven Holli projekteeritud Kiasma muuseumihoonest Helsingis. Kontseptuaalkunsti näitusest ARS 06 "Reaalsustunne" Kiasmas. Eestlastest esineb Mark Raidpere. Vene kunstnikegrupi AEC+F ja vene kunstnike Juri Vassiljevi ning Aleksandr Ponomarjovi töödest näitusel. Ka Gerda Steineri & Jörg Lenzlingeri (Šveits), Martin & Munoz'i (USA, Hispaania), arvutigraafik Charles Sandisoni (SB), videokunstnik Bill Viola (USA) jt. töödest

  3. Ars Industrialis, arsindustrialis.org

    Directory of Open Access Journals (Sweden)

    Frédérique Mingant

    2012-03-01

    Full Text Available The arsindustrialis.org website was created in 2005, when the association Ars Industrialis came into being. The association was founded by a group of philosophers and jurists, on the initiative of philosopher Bernard Stiegler, the former director of the IRCAM (Institut de Recherche et Coordination Acoustique/Musique–Institute of Research and Coordination on Acoustic/Music and the current director of the Department of cultural development at the Centre Georges Pompidou (French National Arts C...

  4. arXiv.org and Physics Education

    Science.gov (United States)

    Ramlo, Susan

    2007-01-01

    The website arXiv.org (pronounced "archive") is a free online resource for full-text articles in the fields of physics, mathematics, computer science, nonlinear science, and quantitative biology that has existed for about 15 years. Available directly at http://www.arXiv.org, this e-print archive is searchable. As of Jan. 3, 2007, arXiv had open…

  5. Radiopacity of root filling materials

    International Nuclear Information System (INIS)

    A method for measuring the radiopacity of root filling materials is described. Direct measurements were made of the optic density values of the materials in comparison with a standard curve relating optic density to the thickness of an aluminium step wedge exposed simultaneously. By proper selection of film and conditions for exposure and development, it was possible to obtain a near-linear standard curve which added to the safety and reproducibility of the method. The technique of radiographic assessment was modified from clinical procedures in evaluating the obturation in radiographs, and it was aimed at detecting slits or voids between the dental wall and the filling material. This radiographic assessment of potensial leakage was compared with actual in vitro lekage of dye (basic fuchsin) into the roots of filled teeth. The result of the investigation show that root filling materials display a very wide range of radiopacity, from less than 3 mm to more than 12 mm of aluminium. It also seem that tooth roots that appear to be well obturated by radiographic evaluation, stand a good chance of beeing resistant to leakage in vitro, and that the type of filling material rather than its radiographic appearance, determines the susceptibility of the filled tooth to leakage in vitro. As an appendix the report contains a survey of radiopaque additives in root filling materials

  6. Mineralogy and Ar-39 - Ar-40 of an old pristine basalt: Thermal history of the HED parent body

    Science.gov (United States)

    Takeda, Hiroshi; Mori, Hiroshi; Bogard, Donald D.

    1994-01-01

    Previous investigations of mineral chemistry and Rb-Sr and Sm-Nd ages indicated that clast,84 from eucrite Yamato 75011 had preserved the pristine nature of its initial crystallization during an early stage of the HED parent body. Microscale mineralogy and Ar-39-Ar-40 ages of this clast, however, revealed local disturbance of microtextures and partially reset ages. This evidence suggests that, in addition to initial crystallization and rapid cooling, the Y75011,84 clast experienced shock deformation, reheating of short duration at higher temperature, and brecciation. These characteristics suggest two or more impact events. Fe-rich olivine filling fractures in pyroxene may have been introduced during the accompanying shock fracturing. The inferred Ar-39-Ar-40 degassing ages for Y75011 matrix and clast, 84 are 3.94 +/- 0.04 Ga and 3.98 +/- 0.03 Ga, respectively. The suggested degassing age for a clast from Y790020, believed to be paired with Y75011, is approximately 4.03 Ga, but could be younger. We consider it likely that all three samples experienced a common degassing event 3.95 +/- 0.05 Ga ago, but we cannot rule out two or more events spaced over a approximately 0.1 Ga interval. Higher temperature extractions of the two clast samples show significantly older apparent ages up to approximately 4.5 Ga and suggest that the time/temperature regime of this event was not sufficient to degas Ar totally. Most likely, the K-Ar ages were reset by thermal metamorphism associated with one or more impact events associated with shock fracturing, formation of Fe-rich olivine veins, and/or meteorite brecciation. The pyroxene annealing that commonly occurs in many eucrites is likely to be a much earlier process than the impact-produced textural changes and reset K-Ar ages observed in these meteorites. The existence of mineralogical and chronological evidence for metamorphism in an otherwise pristine eucrite suggests that the HED parent body experienced an extensive degree of

  7. Removal of root filling materials.

    LENUS (Irish Health Repository)

    Duncan, H.F. Chong, B.S.

    2011-05-01

    Safe, successful and effective removal of root filling materials is an integral component of non-surgical root canal re-treatment. Access to the root canal system must be achieved in order to negotiate to the canal terminus so that deficiencies in the original treatment can be rectified. Since a range of materials have been advocated for filling root canals, different techniques are required for their removal. The management of commonly encountered root filling materials during non-surgical re-treatment, including the clinical procedures necessary for removal and the associated risks, are reviewed. As gutta-percha is the most widely used and accepted root filling material, there is a greater emphasis on its removal in this review.

  8. Ars Memorativa, Ars Oblivionis in Middle English Religious Plays

    Directory of Open Access Journals (Sweden)

    Ciobanu Estella Antoaneta

    2015-12-01

    Full Text Available This paper investigates the multi-layered violence of religious representation in the late medieval York biblical plays, with a focus on the Supper at Emmaus. I read Emmaus (Y40, a play which commemorates the Crucifixion and openly encourages strong anti-Judaism, alongside scenes in an early predecessor pageant, The Crucifixion (Y35, within their contemporary devotional and mnemonic practices, i.e. the confessional Book of Margery Kempe and Thomas Bradwardine’s tract on ars memorativa. Emmaus in particular demonstrates how a fundamentally violent ars memorativa, the legacy of ancient rhetoric to the Middle Ages, also underpins the instruction of the laity in the basics of Christian faith, here with the aid of highly musical prosody and repetition, and thereby hones a biased, intolerant and violence-inured Christian collective memory. To study the York play’s position relative to late medieval mnemonic practices, I frame my analysis within memory studies, enriched with the more specific insights offered by social-psychological, neurobiological and cognitivist studies of memory.

  9. Seismic performance of hillside fills

    OpenAIRE

    Stewart, Jonathan P.; Bray, Jonathan D; McMahon, David J; Smith, Patrick M.; Kropp, Alan L

    2001-01-01

    Permanent ground deformations in unsaturated, compacted hillside fills under seismic loading conditions are discussed, with emphasis given to fill performance during the 1994 Northridge earthquake. These movements represent a significant yet often unrecognized hazard to developed hillside areas, as relatively modest deformations induced widespread damage totaling hundreds of millions of dollars during the Northridge event. The development of grading standards in the Los Angeles area is review...

  10. Determination of filling factors of Active Regions, Coronal Holes and Quiet Sun for the EIT archive 1997-2011

    Science.gov (United States)

    Verbeeck, Cis; Delouille, Veronique; De Visscher, Ruben; Mampaey, Benjamin; Haberreiter, Margit

    2013-04-01

    In previous work, we have proposed a multi-channel unsupervised spatially-constrained multichannel fuzzy clustering algorithm (SPoCA) that automatically segments EUV solar images into Active Regions (AR), Coronal Holes (CH), and Quiet Sun (QS). This algorithm has been running in near real time on AIA data as part of the SDO Feature Finding Team Project since 2010, populating the Heliophysics Events Knowledgebase (HEK) with Active Region and Coronal Hole events. After having corrected for the limb brightening effect, SPoCA computes an optimal clustering with respect to the regions of interest using fuzzy segmentation. The process is fast and automatic. Morphological dilation is employed to assemble neighboring bright AR cores into individual AR regions. Combining SPoCA's detection of AR, and CH on subsequent images allows automatic tracking and naming of any region of interest. We applied SPOCA on SOHO-EIT, SECCHI-EUVI, PROBA2-SWAP, and SDO-AIA, and show in particular the filling factors of AR/QS/CH as well as AR and CH mean intensity time series obtained from the full dataset of synoptic SOHO/EIT images taken between 1997 and 2011. Such segmentation can be used for several applications. Filling factors or AR, QS, and CH can be included into (semi-) empirical models of the solar atmosphere, which can in turn feed models of solar EUV irradiance. Another application is the investigation of active longitudes as well as long-term statistical studies of AR and CH parameters.

  11. Beta decay of 31Ar

    International Nuclear Information System (INIS)

    A complete study of 31Ar beta decay has been made by high-resolution charged-particle and gamma-ray spectroscopy. Beta-delayed radiation was detected by an array of three charged-particle detectors and a large-volume germanium detector. Fifteen new energy levels were discovered in 31Cl. The beta-strength distribution, measured to 14.5 MeV, is compared with a shell-model calculation in the full sd space. The quenching of the Gamow-Teller strength and the isospin impurity of the IAS in 31Cl are discussed. (orig.)

  12. Safety Injection System Filling Using Dynamic Venting

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sung Je; Kim, Wong Bae; Huh, Jin; Lee, Joo Hee; Im, In Young; Kim, Eun kee [KEPCO Engineering and Construction Company, Daejeon (Korea, Republic of)

    2015-05-15

    In the APR+, the water-level elevation of the in-containment refueling water storage tank (IRWST) is lower than the highest piping of the SIS. Since the gravity filling of water from IRWST cannot fill all SIS piping, an SIP or an SCP test line is newly provided in order to allow the dynamic venting of the SIS. NEI 09-10 Revision 1a-A has concluded that use of dynamic venting is an effective means to remove gas from local high points and traps in piping when correctly based on the dynamic flow rate, void volume, Floude number, and the system water volume. In this study, feasibility of the dynamic vent is investigated. The work presented in this study evaluates the SIS and the SCS filling using the dynamic venting which is supposed to be applied to the APR+. The main ideas are as follows; 1. Dynamic venting using SIPs for the APR+ is not appropriate on the basis of 12 inches in diameter and with the flow rate, 1,460 gpm. 2. Because the high point of the SIS and the SCS is located at the piping that the two systems are sharing, the accumulated gas at the highest point can be removed by using the SCPs, and the dimension of the new piping will be determined by its length of them and the number of elbows. The calculated results are shown in Table 2. 3. The applicability of the dynamic venting methods using the SCPs that are mentioned above should be evaluated in the aspect of the system operation after the piping arrangements are settled in the APR+. The assessments to determine the pump operation time are also required.

  13. Laser vision based adaptive fill control system for TIG welding

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The variation of joint groove size during tungsten inert gas (TIG) welding will result in the non-uniform fill of deposited metal. To solve this problem, an adaptive fill control system was developed based on laser vision sensing. The system hardware consists of a modular development kit (MDK) as the real-time image capturing system, a computer as the controller, a D/A conversion card as the interface of controlled variable output, and a DC TIG welding system as the controlled device. The system software is developed and the developed feature extraction algorithm and control strategy are of good accuracy and robustness. Experimental results show that the system can implement adaptive fill of melting metal with high stability, reliability and accuracy. The groove is filled well and the quality of the weld formation satisfies the relevant industry criteria.

  14. Ars discendi, ars docendi : programme Pascal

    OpenAIRE

    Goyet, Thérèse

    2016-01-01

    Le latin de l’intitulé, c’est pour le plaisir, mais on peut lui donner quelques autres justifications. Ars évoque tout à la fois le savoir‑faire, le talent, la compétence professionnelle, le goût de la solution élégante. La parataxe permet le va-et-vient entre le thème et le prédicat (sujet et attribut). On interprétera au choix : savoir étudier, c’est savoir enseigner. Ou : pour apprendre, il faut enseigner ; ou : l’enseignement consiste en étude ; et d’autres variations communes sur une vér...

  15. 40Ar/39Ar dating of the Late Cretaceous

    International Nuclear Information System (INIS)

    As part of the wider European GTS Next project, I propose new constraints on the ages of the Late Cretaceous, derived from a multitude of geochronological techniques, and successful stratigraphic interpretations from Canada and Japan. In the Western Canada Sedimentary Basin, we propose a new constraint on the age of the K/Pg boundary in the Red Deer River section (Alberta, Canada). We were able to cyclo-stratigraphically tune sediments in a non-marine, fluvial environment utilising high-resolution proxy records suggesting a 11-12 precession related cyclicity. Assuming the 40Ar/39Ar method is inter-calibrated with the cyclo-stratigraphy, the apparent age for C29r suggests that the K/Pg boundary falls between eccentricity maxima and minima, yielding an age of the C29r between 65.89 ± 0.08 and 66.30 ± 0.08 Ma. Assuming that the bundle containing the coal horizon represents a precession cycle, the K/Pg boundary is within the analytical uncertainty of the youngest zircon population achieving a revised age for the K/Pg boundary as 65.75 ± 0.06 Ma. The Campanian - Maastrichtian boundary is preserved in the sedimentary succession of the Horseshoe Canyon Formation and has been placed 8 m below Coal nr. 10. Cyclo-stratigraphic studies show that the formation of these depositional sequences (alternations) of all scales are influenced directly by sea-level changes due to precession but more dominated by eccentricity cycles proved in the cyclo-stratigraphic framework and is mainly controlled by sand horizons, which have been related by auto-cyclicity in a dynamic sedimentary setting. Our work shows that the Campanian - Maastrichtian boundary in the Western Canada Sedimentary Basin coincides with 2.5 eccentricity cycles above the youngest zircon age population at the bottom of the section and 4.9 Myr before the Cretaceous - Palaeogene boundary (K/Pg), and thus corresponds to an absolute age of 70.65 ± 0.09 Ma producing an 1.4 Myr younger age than recent published ages

  16. Reorientation of quantum Hall stripes within a partially filled Landau level

    Science.gov (United States)

    Shi, Q.; Zudov, M. A.; Watson, J. D.; Gardner, G. C.; Manfra, M. J.

    2016-03-01

    We investigate the effect of the filling factor on transport anisotropies, known as stripes, in high Landau levels of a two-dimensional electron gas. We find that at certain in-plane magnetic fields, the stripes orientation is sensitive to the filling factor within a given Landau level. This sensitivity gives rise to the emergence of stripes away from half-filling while orthogonally oriented, native stripes reside at half-filling. This switching of the anisotropy axes within a single Landau level can be attributed to a strong dependence of the native symmetry-breaking potential on the filling factor.

  17. Subterranean production of neutrons, $^{39}$Ar and $^{21}$Ne: Rates and uncertainties

    OpenAIRE

    Šrámek, Ondřej; Stevens, Lauren; William F. McDonough; Mukhopadhyay, Sujoy; Peterson, R. J.

    2015-01-01

    Accurate understanding of the subsurface production of radionuclide $^{39}$Ar rate is necessary for argon dating techniques and noble gas geochemistry of the shallow and the deep Earth, and is also of interest to the WIMP dark matter experimental particle physics community. Our new calculations of subsurface production of neutrons, $^{21}$Ne, and $^{39}$Ar take advantage of the best available tools of nuclear physics to obtain reaction cross sections and spectra (TALYS) and to evaluate neutro...

  18. Ultrasonically determined fill pressure and density in closed spherical shells

    International Nuclear Information System (INIS)

    Experiments have been conducted in which the D2 fill pressure has been determined for several closed millimeter-size aluminum and beryllium shells. The vibrational resonance frequency spectrum of the shells was used to calculate the sound velocity of the interior gas. This velocity, along with the equation-of-state, determined the gas pressure and density. The accuracy in determining the fill conditions is within 0.5% in both pressure and density for near critical density (ρ approx-gt 9 mol/L) gas over a wide range of temperatures (190 K to 300 K). Reduced accuracy was apparent at low density. An attempt was made to determine the fill density of one shell by acoustic observation of the dew point temperature. While this temperature was recorded very accurately, the uncertainty in the saturated vapor density curve near the critical point yielded inaccurate results. These methods were shown to be unaffected by small deviations in the sphericity of the gas-filled cavity

  19. Transient surface photovoltage studies of bare and Ni-filled porous silicon performed in different ambients

    Science.gov (United States)

    Granitzer, Petra; Rumpf, Klemens; Strzhemechny, Yuri; Chapagain, Puskar

    2014-08-01

    Mesoporous silicon and porous silicon/Ni nanocomposites have been investigated in this work employing light-dark surface photovoltage (SPV) transients to monitor the response of surface charge dynamics to illumination changes. The samples were prepared by anodization of a highly n-doped silicon wafer and a subsequent electrodepositing of Ni into the pores. The resulting pores were oriented towards the surface with an average pore diameter of 60 nm and the thickness of the porous layer of approximately 40 μm. SPV was performed on a bare porous silicon as well as on a Ni-filled porous silicon in vacuum and in different gaseous environments (O2, N2, Ar). A significant difference was observed between the `light-on' and `light-off' SPV transients obtained in vacuum and those observed in gaseous ambiences. Such behavior could be explained by the contribution to the charge exchange in gas environments from chemisorbed and physisorbed species at the semiconductor surface.

  20. Ion species and electron behavior in capacitively coupled Ar and O2 plasma

    International Nuclear Information System (INIS)

    We investigated the change in electron density using the plasma frequency by the wave cutoff method, and the behavior of ion species with a quadrupole mass spectrometer (QMS) in pure Ar and O2 and mixed O2/Ar plasmas. The change in electron and ion density in pure Ar and O2 plasmas was evaluated while varying such process conditions as rf power and pressure. We found that electron density in a pure Ar and O2 discharge is closely correlated to loss and generation of ions. The electron densities in both pure Ar and O2 plasmas increase with rf plasma power but show different dependence on pressure due to different loss mechanism for each type of gas. The addition of Ar to an O2 plasma significantly enhances the electron density due to the rapid increase of Ar+ ions regardless of the pressure. Also, Ar addition results in more dissociation of O2, which gives more atomic O. These results indicate that the electron density calculated from the plasma frequency, measured by the wave cutoff method, is well explained by the ion behavior, as characterized by QMS

  1. Dating blueschist metamorphism: a combined 40Ar/39Ar and electron microprobe approach

    International Nuclear Information System (INIS)

    40Ar/39Ar and electron microprobe examination of blueschist samples from the Iceberg Lake schist, southern Alaska suggest that phengite inclusions are the source of 40Ar in crossite. Because such fine-grained inclusions may be susceptible to argon loss, caution should be exercised in interpreting K-Ar ages from this phase, and possibly other low-K amphiboles from blueschist suites. The estimated blocking temperature for phengite in the matrix (3140 to 4500C), however, is close to the estimated peak metamorphic temperatures (3250 +- 500C), suggesting that phengite 40Ar/39Ar plateau dates may coincide closely with the time of blueschist metamorphism. (author)

  2. Toward a high-resolution 40Ar/39Ar geochronology of the Tatun Volcano Group, Taiwan

    Science.gov (United States)

    Mesko, G. T.; Song, S.; Chang, S.; Hemming, S. R.; Turrin, B. D.

    2010-12-01

    Creek sanidine monitor standard, with an assumed age of 1.193±.001Ma (Nomade et al., 2005, Chemical Geology). Multiple-grain step-heating analyses using 3 to 5 steps were executed on several aliquots of the samples using a VG5400 noble gas mass spectrometer equipped with a 30W CO2 laser. Ages were calculated using the isochron method on all the steps run for each sample in order to avoid the necessity of assuming an initial composition and so all of the data points from a single irradiation could be plotted together. The results have yielded ages far younger than previously reported in all of the TVG, with very unradiogenic Ar and with 40Ar/36Ar intercepts that are mostly higher than the atmospheric ratio of 298.56±0.31 (Lee et al., 2006, Geochimica et Cosmochimica Acta). The second eruptive stage (using eruptive stages mapped by Lai et al., 2010, TAO) yielded ages in different locations of .053±.012Ma and .052±.014Ma. A third sample that was previously mapped in this stage yielded an age of .17±.03Ma. We have not yet been successful at obtaining reliable results on the stratigraphically youngest sample.

  3. Variable leak gas source

    Science.gov (United States)

    Henderson, Timothy M.; Wuttke, Gilbert H.

    1977-01-01

    A variable leak gas source and a method for obtaining the same which includes filling a quantity of hollow glass micro-spheres with a gas, storing said quantity in a confined chamber having a controllable outlet, heating said chamber above room temperature, and controlling the temperature of said chamber to control the quantity of gas passing out of said controllable outlet. Individual gas filled spheres may be utilized for calibration purposes by breaking a sphere having a known quantity of a known gas to calibrate a gas detection apparatus.

  4. A scintillating gas detector for 2D dose measurements in clinical carbon beams

    International Nuclear Information System (INIS)

    A two-dimensional position sensitive dosimetry system based on a scintillating gas detector has been developed for pre-treatment verification of dose distributions in hadron therapy. The dosimetry system consists of a chamber filled with an Ar/CF4 scintillating gas mixture, inside which two cascaded gas electron multipliers (GEMs) are mounted. A GEM is a thin kapton foil with copper cladding structured with a regular pattern of sub-mm holes. The primary electrons, created in the detector's sensitive volume by the incoming beam, drift in an electric field towards the GEMs and undergo gas multiplication in the GEM holes. During this process, photons are emitted by the excited Ar/CF4 gas molecules and detected by a mirror-lens-CCD camera system. Since the amount of emitted light is proportional to the dose deposited in the sensitive volume of the detector by the incoming beam, the intensity distribution of the measured light spot is proportional to the 2D hadron dose distribution. For a measurement of a 3D dose distribution, the scintillating gas detector is mounted at the beam exit side of a water-bellows phantom, whose thickness can be varied in steps. In this work, the energy dependence of the output signal of the scintillating gas detector has been verified in a 250 MeV/u clinical 12C ion beam by means of a depth-dose curve measurement. The underestimation of the measured signal at the Bragg peak depth is only 9% with respect to an air-filled ionization chamber. This is much smaller than the underestimation found for a scintillating Gd2O2S:Tb ('Lanex') screen under the same measurement conditions (43%). Consequently, the scintillating gas detector is a promising device for verifying dose distributions in high LET beams, for example to check hadron therapy treatment plans which comprise beams with different energies

  5. A scintillating gas detector for 2D dose measurements in clinical carbon beams

    Science.gov (United States)

    Seravalli, E.; de Boer, M.; Geurink, F.; Huizenga, J.; Kreuger, R.; Schippers, J. M.; van Eijk, C. W. E.; Voss, B.

    2008-09-01

    A two-dimensional position sensitive dosimetry system based on a scintillating gas detector has been developed for pre-treatment verification of dose distributions in hadron therapy. The dosimetry system consists of a chamber filled with an Ar/CF4 scintillating gas mixture, inside which two cascaded gas electron multipliers (GEMs) are mounted. A GEM is a thin kapton foil with copper cladding structured with a regular pattern of sub-mm holes. The primary electrons, created in the detector's sensitive volume by the incoming beam, drift in an electric field towards the GEMs and undergo gas multiplication in the GEM holes. During this process, photons are emitted by the excited Ar/CF4 gas molecules and detected by a mirror-lens-CCD camera system. Since the amount of emitted light is proportional to the dose deposited in the sensitive volume of the detector by the incoming beam, the intensity distribution of the measured light spot is proportional to the 2D hadron dose distribution. For a measurement of a 3D dose distribution, the scintillating gas detector is mounted at the beam exit side of a water-bellows phantom, whose thickness can be varied in steps. In this work, the energy dependence of the output signal of the scintillating gas detector has been verified in a 250 MeV/u clinical 12C ion beam by means of a depth-dose curve measurement. The underestimation of the measured signal at the Bragg peak depth is only 9% with respect to an air-filled ionization chamber. This is much smaller than the underestimation found for a scintillating Gd2O2S:Tb ('Lanex') screen under the same measurement conditions (43%). Consequently, the scintillating gas detector is a promising device for verifying dose distributions in high LET beams, for example to check hadron therapy treatment plans which comprise beams with different energies.

  6. High density plasma reactive ion etching of CoFeB magnetic thin films using a CH4/Ar plasma

    International Nuclear Information System (INIS)

    In this study, high density plasma reactive ion etching of CoFeB magnetic thin films was investigated using CH4/Ar and CH4/O2/Ar gas mixes. The etch rate, etch selectivity and etch profile of CoFeB thin films were obtained as a function of gas concentration and etch parameters. The etch rate of CoFeB thin films and Ti hard mask gradually decreased with increasing CH4 or O2 concentrations. As the CH4 gas was added to Ar gas, the etch profile of the CoFeB thin films improved. The addition of O2 gas into the CH4/Ar gas mix also led to anisotropic etching of the CoFeB thin films. With an increase in the dc-bias voltage supplied to the substrate and a decrease in gas pressure, the etch rates increased and the etch profile became vertical without any redepositions or etch residues. Based on the etch characteristics and surface analysis of the etched films by X-ray photoelectron spectroscopy, it can be concluded that the etch mechanism of CoFeB thin films in CH4/Ar and CH4/O2/Ar plasmas does not follow the reactive ion etch mechanism but rather a chemically assisted physical sputtering mechanism.

  7. Triaxial superdeformation in $^{40}$Ar

    CERN Document Server

    Taniguchi, Yasutaka; Kimura, Masaaki; Ikeda, Kiyomi; Horiuchi, Hisashi; Ideguchi, Eiji

    2010-01-01

    Superdeformed (SD) states in $^{40}$Ar have been studied using the deformed-basis antisymmetrized molecular dynamics. Low energy states were calculated by the parity and angular momentum projection (AMP) and the generator coordinate method (GCM). Basis wave functions were obtained by the energy variation with a constraint on the quadrupole deformation parameter $\\beta$, while other quantities such as triaxiality $\\gamma$ were optimized by the energy variation. By the GCM calculation, an SD band is obtained just above the ground state band. The SD band involves a $K^\\pi = 2^+$ side band due to the triaxiality. The calculated quadrupole electric transition strengths of the SD band reproduce well the experimental values. Triaxiality is significantly important to understand low-lying states.

  8. Ars grammatica de Dionisio Tracio

    Directory of Open Access Journals (Sweden)

    Beltrán Jorge Enrique

    2003-06-01

    Full Text Available

    Ars Grammatica de Dionisio Tracio (170-90 a. C fue la primera gramática griega que se escribió. Su contenido y método fueron modelos que siguieron las gramáticas escolares posteriores. La versión española que se presenta ahora responde a la necesidad que se tenía en nuestro medio de una traducción completa de este texto. Finalmente, se acompaña la traducción de una introducción y de abundantes notas, en un intento por hacerla comprensible para el hablante del español, no necesariamente conocedor de la lengua griega.

  9. QENS investigation of filled rubbers

    CERN Document Server

    Triolo, A; Desmedt, A; Pieper, J K; Lo Celso, F; Triolo, R; Negroni, F; Arrighi, V; Qian, H; Frick, B

    2002-01-01

    The polymer segmental dynamics is investigated in a series of silica-filled rubbers. The presence of inert fillers in polymers greatly affects the mechanical and physical performance of the final materials. For example, silica has been proposed as a reinforcing agent of elastomers in tire production. Results from quasielastic neutron scattering and Dynamic Mechanical Thermal Analysis (DMTA) measurements are presented on styrene-ran-butadiene rubber filled with silica. A clear indication is obtained of the existence of a bimodal dynamics, which can be rationalized in terms of the relaxation of bulk rubber and the much slower relaxation of the rubber adsorbed on the filler surface. (orig.)

  10. QENS investigation of filled rubbers

    International Nuclear Information System (INIS)

    The polymer segmental dynamics is investigated in a series of silica-filled rubbers. The presence of inert fillers in polymers greatly affects the mechanical and physical performance of the final materials. For example, silica has been proposed as a reinforcing agent of elastomers in tire production. Results from quasielastic neutron scattering and Dynamic Mechanical Thermal Analysis (DMTA) measurements are presented on styrene-ran-butadiene rubber filled with silica. A clear indication is obtained of the existence of a bimodal dynamics, which can be rationalized in terms of the relaxation of bulk rubber and the much slower relaxation of the rubber adsorbed on the filler surface. (orig.)

  11. Range-separated density functional theory: A 4-component relativistic study of the rare gas dimers He2, Ne2, Ar2, Kr2, Xe2, Rn2 and Uuo2

    International Nuclear Information System (INIS)

    Highlights: ► First implementation of 4-component relativistic long-range MP2/short-range DFT. ► First complete study of spectroscopic constants of the rare gas dimers He2–Uuo2. ► MP2-srLDA has a performance similar to pure MP2, but the overbinding of MP2 can be tuned by the range-separation parameter. - Abstract: We report the implementation of long-range second-order Møller–Plesset perturbation theory coupled with short-range density functional theory (MP2-srDFT) based on the 4-component relativistic Dirac–Coulomb Hamiltonian. The range separation of the two-electron interaction is based on the error function, such that the long-range interaction, to be handled by wave function theory, corresponds to the potential of finite electrons with a Gaussian charge distribution. We argue that the interelectronic distance associated with the range-separation parameter should accordingly be determined from a Gaussian rather than a hard-sphere model. As a first application of our relativistic MP2-srDFT implementation we calculate spectroscopic constants of the complete series of homoatomic rare gas dimers, from helium to the superheavy element 118 and with bonding dominated by dispersion forces. We find that the MP2-srDFT method is less sensitive to the basis set quality than pure MP2, but for the heavier rare gas dimers the computational cost is approximately the same as for pure MP2 if one seeks convergence with respect to both basis set and number of correlated electrons. The inclusion of a short-range DFT contribution allows to dampen the tendency of pure MP2 to overbind the heavier dimers, but it is difficult to find an optimal range-separation parameter for the whole series of diatomics. Interestingly, MP2-srLDA shows better performance than MP2-srPBE for the selected molecules.

  12. (40)Ar/(39)Ar dating, paleomagnetism, and tephrochemistry of Pliocene strata of the hominid-bearing Woranso-Mille area, west-central Afar Rift, Ethiopia.

    Science.gov (United States)

    Deino, Alan L; Scott, Gary R; Saylor, Beverly; Alene, Mulugeta; Angelini, Joshua D; Haile-Selassie, Yohannes

    2010-02-01

    (40)Ar/(39)Ar dating of tuffs and mafic lavas, tephra geochemistry, and paleomagnetic reversal stratigraphy have been used to establish the chronostratigraphy of the Pliocene hominid-bearing fossiliferous succession at Woranso-Mille, a paleontological study area in the western part of the central Afar region of Ethiopia. The succession in the northwestern part of the study area ranges in (40)Ar/(39)Ar age from 3.82-3.570 Ma, encompassed by paleomagnetic subchron C2Ar (4.187-3.596 Ma). One of the major tuff units, locally named the Kilaytoli tuff, is correlative on the basis of age and geochemistry to the Lokochot Tuff of the Turkana Basin. A hominid partial skeleton (KSD-VP-1) was found in strata whose precise stratigraphic position and age is still under investigation, but is believed to correspond to the later part of this interval. Woranso-Mille fills a significant gap in the fossil record of northeastern Africa at the time of the lower to middle Pliocene transition, when many extant species lineages of African fauna were established. PMID:20034653

  13. Atmospheric pressure plasma jet utilizing Ar and Ar/H2O mixtures and its applications to bacteria inactivation

    International Nuclear Information System (INIS)

    An atmospheric pressure plasma jet generated with Ar with H2O vapor is characterized and applied to inactivation of Bacillus subtilis spores. The emission spectra obtained from Ar/H2O plasma shows a higher intensity of OH radicals compared to pure argon at a specified H2O concentration. The gas temperature is estimated by comparing the simulated spectra of the OH band with experimental spectra. The excitation electron temperature is determined from the Boltzmann's plots and Stark broadening of the hydrogen Balmer Hβ line is applied to measure the electron density. The gas temperature, excitation electron temperature, and electron density of the plasma jet decrease with the increase of water vapor concentration at a fixed input voltage. The bacteria inactivation rate increases with the increase of OH generation reaching a maximum reduction at 2.6% (v/v) water vapor. Our results also show that the OH radicals generated by the Ar/H2O plasma jet only makes a limited contribution to spore inactivation and the shape change of the spores before and after plasma irradiation is discussed. (physics of gases, plasmas, and electric discharges)

  14. Development of a Low-Level Ar-37 Calibration Standard

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Richard M.; Aalseth, Craig E.; Bowyer, Ted W.; Day, Anthony R.; Fuller, Erin S.; Haas, Derek A.; Hayes, James C.; Hoppe, Eric W.; Humble, Paul H.; Keillor, Martin E.; LaFerriere, Brian D.; Mace, Emily K.; McIntyre, Justin I.; Miley, Harry S.; Myers, Allan W.; Orrell, John L.; Overman, Cory T.; Panisko, Mark E.; Seifert, Allen

    2016-03-07

    Argon-37 is an important environmental signature of an underground nuclear explosion. Producing and quantifying low-level 37Ar standards is an important step in the development of sensitive field measurement instruments for use during an On-Site Inspection, a key provision of the Comprehensive Nuclear-Test-Ban Treaty. This paper describes progress at Pacific Northwest National Laboratory (PNNL) in the development of a process to generate and quantify low-level 37Ar standard material, which can then be used to calibrate sensitive field systems at activities consistent with soil background levels. The 37Ar used for our work was generated using a laboratory-scale, high-energy neutron source to irradiate powdered samples of calcium carbonate. Small aliquots of 37Ar were then extracted from the head space of the irradiated samples. The specific activity of the head space samples, mixed with P10 (90% stable argon:10% methane by mole fraction) count gas, is then derived using the accepted Length-Compensated Internal-Source Proportional Counting method. Due to the low activity of the samples, a set of three Ultra-Low Background Proportional-Counters designed and fabricated at PNNL from radio-pure electroformed copper was used to make the measurements in PNNL’s shallow underground counting laboratory. Very low background levels (<10 counts/day) have been observed in the spectral region near the 37Ar emission feature at 2.8 keV. Two separate samples from the same irradiation were measured. The first sample was counted for 12 days beginning 28 days after irradiation, the second sample was counted for 24 days beginning 70 days after irradiation (the half-life of 37Ar is 35.0 days). Both sets of measurements were analyzed and yielded very similar results for the starting activity (~0.1 Bq) and activity concentration (0.15 mBq/ccSTP argon) after P10 count gas was added. A detailed uncertainty model was developed based on the ISO Guide to the Expression of Uncertainty in

  15. Pulsed electron beam propagation in argon and nitrogen gas mixture

    International Nuclear Information System (INIS)

    The paper presents the results of current measurements for the electron beam, propagating inside a drift tube filled in with a gas mixture (Ar and N2). The experiments were performed using the TEA-500 pulsed electron accelerator. The main characteristics of electron beam were as follows: 60 ns pulse duration, up to 200 J energy, and 5 cm diameter. The electron beam propagated inside the drift tube assembled of three sections. Gas pressures inside the drift tube were 760 ± 3, 300 ± 3, and 50 ± 1 Torr. The studies were performed in argon, nitrogen, and their mixtures of 33%, 50%, and 66% volume concentrations, respectively

  16. Analysis of the adsorbates and determination of the adsorption sites on Si(1 1 1)-7x7 after a large amount of Ar exposure at room temperature

    International Nuclear Information System (INIS)

    The surface structure of Si(1 1 1)-7x7 after exposure to a large dose of Ar at room temperature has been investigated by scanning tunneling microscopy and the adsorbates on the surface have been analyzed. It was found that Ar does not adsorb on the Si(1 1 1)-7x7 surface. The adsorption is dominated by the impurities, most likely to be H2O, in the Ar gas. The impurities dissociatively adsorb on the Si(1 1 1)-7x7 surface and appear as dark spots in both empty and filled state images due to the diminution of Fermi-level local density of states over the adsorption sites. The chemisorption is site selective and the ratio of reacted center sites vs. reacted corner sites is about 2:1, indicating that center-adatoms react with H2O twice as fast as corner-adatoms. After annealing the substrate to 660 deg C, this ratio keeps invariant while the total number of dark sites is significantly decreased. The remaining dark spots on the Si(1 1 1)-7x7 surface after annealing at 660 deg C are likely to be surface vacancies caused by the desorption of SiO

  17. Brain Responses to Filled Gaps

    Science.gov (United States)

    Hestvik, Arild; Maxfield, Nathan; Schwartz, Richard G.; Shafer, Valerie

    2007-01-01

    An unresolved issue in the study of sentence comprehension is whether the process of gap-filling is mediated by the construction of empty categories (traces), or whether the parser relates fillers directly to the associated verb's argument structure. We conducted an event-related potentials (ERP) study that used the violation paradigm to examine…

  18. Contemporary root canal filling strategies

    NARCIS (Netherlands)

    A.T. Moinzadeh

    2016-01-01

    Currently, clinicians can choose from a wide range of root canal filling materials and techniques, some of which have been evaluated in this thesis. Methacrylate resin-based sealers suffer from polymerization shrinkage stresses. This limitation may partly be overcome by a two-step cementation proced

  19. Gas filling pattern in Paleozoic marine carbonate reservoir of Ordos Basin%鄂尔多斯盆地海相碳酸盐岩层系天然气成藏研究

    Institute of Scientific and Technical Information of China (English)

    刘全有; 金之钧; 王毅; 韩品龙; 陶冶; 王起琮; 任站利; 李文厚

    2012-01-01

    Two sets of high quality marine source rocks in Ordos basin, including Upper Oidovician marl in Beiguoshan Formation and Middle Ordovician shale at middle and bottom parts of Pingliang Formation, were a progenitor of the past crude oil in marine carbonate reservoir and present oil-type gas which was sourced from oil cracking in Jingbian gas pooL Two sets of marine source rocks were distributed in the west and southwest of Ordos basin as " L" shape and absent in internal basin, with thickness of about 50 ~ 350m. TOC value in Middle Ordoviuian Pingiiang shale is in range of 0.5% -1.2% (average value = 0.9%), and Pingiiang limestone has TOC value of 0. 2% ~ 0. 4% (average value = 0. 3% ). TOC value in Upper Ordovician Beiguoshan source rock is more than that of Pingiiang source rock, with TOC value of 0. 22% - 3. 3% ( average value = 0.93% ). At end of Triassie, crude oil generated from two sets of high quality marine source rocks was migrated into the slope of Central Paleouplift and accumulated as an oil pooL At period of Jurassic and Early Craterous, large buried thickness and increasing geothermal gradient made not only high-over maturity of marine source rocks, but also temperature of oil reservoir more than 180t, and then the early etude oil started thermally cracking into natural gas. Increase of gas reservoir pressure which was formed by thermal cracking of oil and gas pushed natural gas diffused. At the IV episode of Yanshan Movement (corresponding to Later Cretaceous), large scale continue extrusion and uplift in the eastern part of Ordos Basin caused the structural reversion of gas reservoir from west high and east low to east high and west low, that is called as structural hinge. Thus, the predominance of oil and gas accumulation in the Central Paleo-uplift was changed. Oil cracking gas was migrated toward east or northeast, but gas was laterally blocked by salt, gypsum and fine carbonate in the eastern basin. The Carboniferous bauxitic mudstone beneath

  20. XRD-based 40Ar/39Ar age correction for fine-grained illite, with application to folded carbonates in the Monterrey Salient (northern Mexico)

    Science.gov (United States)

    Fitz-Díaz, Elisa; Hall, Chris M.; van der Pluijm, Ben A.

    2016-05-01

    Due to their minute size, 40Ar/39Ar analysis of illite faces significant analytical challenges, including mineral characterization and, especially, effects of grain size and crystallography on 39Ar recoil. Quantifying the effects of 39Ar recoil requires the use of sample vacuum encapsulation during irradiation, which permits the measurement of the fraction of recoiled 39Ar as well as the 39Ar and 40Ar∗ retained within illite crystals that are released during step heating. Total-Gas Ages (TGA) are calculated by using both recoiled and retained argon, which is functionally equivalent to K-Ar ages, while Retention Ages (RA) only involve retained Ar in the crystal. Natural applications have shown that TGA fits stratigraphic constraints of geological processes when the average illite crystallite thickness (ICT) is smaller than 10 nm, and that RA matches these constraints for ICTs larger than 50 nm. We propose a new age correction method that takes into account the average ICT and corresponding recoiled 39Ar for a sample, with X-ray Corrected Ages (XCA) lying between Total-Gas and Retention Ages depending on ICT. This correction is particularly useful in samples containing authigenic illite formed in the anchizone, with typical ICT values between 10 and 50 nm. In three samples containing authigenic illite from Cretaceous carbonates in the Monterrey Salient in northern Mexico, there is a range in TGAs among the different size-fractions of 46-49, 36-43 and 40-52 Ma, while RAs range from 54-64, 47-52 and 53-54 Ma, respectively. XCA calculations produce tighter age ranges for these samples of 52.5-56, 45.5-48.5 and 49-52.5 Ma, respectively. In an apparent age vs ICT or %2M 1illite plot, authigenic illite grains show a slope that is in general slightly positive for TGA, slightly negative for RA, but close to zero for XCA, with thinner crystallites showing more dispersion than thicker ones. In order to test if dispersion is due to a different formation history or the result

  1. Polymerisationseigenschaften von Bulk-Fill Kompositen

    OpenAIRE

    Maier, Eva

    2015-01-01

    Hintergrund und Ziele: Untersuchung der Polymerisationseigenschaften von Bulk-Fill Kompositen bzgl. Konversionsrate (degree of conversion = DC), Vickers-Härte (HV), Polymerisationsschrumpfungsstress (PSS) und Polymerisationsvolumenschrumpfung (PVS) im Vergleich zu konventionellen Kompositen. Material und Methode: Untersucht wurden die Bulk-Fill Komposite Filtek Bulk Fill Flowable (FBF, 3M ESPE, Seefeld), Surefil Smart Dentin Replacement (SDR, Dentsply, Konstanz), Tetric EvoCeram Bulk Fill...

  2. Aging Studies of Filled and Unfilled VCE

    Energy Technology Data Exchange (ETDEWEB)

    Letant, S; Herberg, J; Alviso, C; Small, W; Mulcahy, H; Pearson, M; Wilson, T; Chinn, S; Maxwell, R

    2009-11-10

    This report presents data on the effects of temperature and gamma radiation on the chemical and structural properties of both filled and unfilled VCE material produced by the Kansas City Plant using WR-qualified processes. Thermal effects up to 300 C and gamma irradiation doses of 1 MRad and 25 MRad were investigated under atmospheric conditions. Characterization techniques used in the study comprise Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), Tensile Testing, Solid Phase MicroExtraction - Gas Chromatography/Mass Spectrometry (SPME-GC/MS), phenol extraction followed by HPLC, and various Nuclear Magnetic Resonance (NMR) techniques including: {sup 13}C, {sup 13}C {l_brace}{sup 1}H{r_brace} cross polarization (CP), {sup 1}H magic angle spinning (MAS), 13C{l_brace}{sup 1}H{r_brace} Wide-line-Separation (2D-WISE) and development of Center band-Only Detection of Exchange (CODEX).

  3. 244-AR Vault Interim Stabilization Project Plan

    International Nuclear Information System (INIS)

    The 244-AR Vault Facility, constructed between 1966 and 1968, was designed to provide lag storage and treatment for the Plutonium-Uranium Extraction Facility (PUREX) tank farm sludges. Tank farm personnel transferred the waste from the 244-AR Vault Facility to B Plant for recovery of cesium and strontium. B Plant personnel then transferred the treatment residuals back to the tank farms for storage of the sludge and liquids. The last process operations, which transferred waste supporting the cesium/strontium recovery mission, occurred in April 1978. After the final transfer in 1978, the 244-AR facility underwent a cleanout. However, 2,271 L (600 gal) of sludge were left in Tank 004AR from an earlier transfer from Tank 241-AX-104. When the cleanout was completed, the facility was placed in a standby status. The sludge had been transferred to Tank 004AR to support Pacific Northwest National Laboratory [PNNL] vitrification work. Documentation of waste transfers suggests that a portion of the sludge may have been moved from Tank 004AR to Tank 002AR in preparation for transfer back to the AX Tank Farm; however, quantities of the sludge that were moved to Tank 002AR from that transfer must be estimated

  4. Numerical simulation and analysis of mould filling process in lost foam casting

    Institute of Scientific and Technical Information of China (English)

    Jiang Junxia; Wu Zhichao; Chen Liliang; Hao Jing

    2008-01-01

    In lost foam casting (LFC) the foam pattern is the key criterion, and the filling process is crucial to ensure the high quality of the foam pattern. Filling which lacks uniformity and denseness will cause various defects and affect the surface quality of the casting. The influential factors of the filling process are realized in this research. Optimization of the filling process, enhancement of efficiency, decrease of waste, etc., are obtained by the numerical simulation of the filling process using a computer. The equations governing the dense gas-solid two-phase flow are established, and the physical significance of each equation is discussed. The Euler/Lagrange numerical model is used to simulate the fluid dynamic characteristics of the dense two-phase flow during the mould filling process in lost foam casting. The experiments and numerical results showed that this method can be a very promising tool in the mould filling simulation of beads' movement.

  5. The Coronae of AR Lac

    CERN Document Server

    Huenemoerder, D P; Drake, J J; Sanz-Forcada, J; Canizares, Claude R.; Drake, Jeremy J.; Huenemoerder, David P.; Sanz-Forcada, Jorge

    2003-01-01

    We observed the coronally active eclipsing binary, AR Lac, with the High Energy Transmission Grating on Chandra for a total of 97 ks, spaced over five orbits, at quadratures and conjunctions. Contemporaneous and simultaneous EUV spectra and photometry were also obtained with the Extreme Ultraviolet Explorer. Significant variability in both X-ray and EUV fluxes were observed, dominated by at least one X-ray flare and one EUV flare. We saw no evidence of primary or secondary eclipses. X-ray flux modulation was largest at high temperature, indicative of flare heating of coronal plasma. Line widths interpreted in terms of Doppler broadening suggest that both binary stellar components are active. From line fluxes obtained from total integrated spectra, we have modeled the emission measure and abundance distributions. A strong maximum was found in the differential emission measure, characterized by peaks at log T = 6.9 and 7.4, together with a weak but significant cooler maximum near log T=6.2, and a moderately str...

  6. New accurate measurement of 36ArH+ and 38ArH+ ro-vibrational transitions by high resolution IR absorption spectroscopy

    CERN Document Server

    Cueto, M; Barlow, M J; Swinyard, B M; Herrero, V J; Tanarro, I; Domenech, J L

    2014-01-01

    The protonated Argon ion, $^{36}$ArH$^{+}$, has been identified recently in the Crab Nebula (Barlow et al. 2013) from Herschel spectra. Given the atmospheric opacity at the frequency of its $J$=1-0 and $J$=2-1 rotational transitions (617.5 and 1234.6 GHz, respectively), and the current lack of appropriate space observatories after the recent end of the Herschel mission, future studies on this molecule will rely on mid-infrared observations. We report on accurate wavenumber measurements of $^{36}$ArH$^{+}$ and $^{38}$ArH$^{+}$ rotation-vibration transitions in the $v$=1-0 band in the range 4.1-3.7 $\\mu$m (2450-2715 cm$^{-1}$). The wavenumbers of the $R$(0) transitions of the $v$=1-0 band are 2612.50135$\\pm$0.00033 and 2610.70177$\\pm$0.00042 cm$^{-1}$ ($\\pm3\\sigma$) for $^{36}$ArH$^{+}$ and $^{38}$ArH$^{+}$, respectively. The calculated opacity for a gas thermalized at a temperature of 100 K and a linewidth of 1 km.s$^{-1}$ of the $R$(0) line is $1.6\\times10^{-15}\\times N$($^{36}$ArH$^+$). For column densities ...

  7. 40Ar/39Ar ages of lunar impact glasses: Relationships among Ar diffusivity, chemical composition, shape, and size

    CERN Document Server

    Zellner, N E B

    2015-01-01

    Lunar impact glasses, quenched melts produced during cratering events on the Moon, have the potential to provide not only compositional information about both the local and regional geology of the Moon but also information about the impact flux over time. We present in this paper the results of 73 new 40Ar/39Ar analyses of well-characterized, inclusion-free lunar impact glasses and demonstrate that size, shape, chemical composition, fraction of radiogenic 40Ar retained, and cosmic ray exposure (CRE) ages are important for 40Ar/39Ar investigations of these samples. Specifically, analyses of lunar impact glasses from the Apollo 14, 16, and 17 landing sites indicate that retention of radiogenic 40Ar is a strong function of post-formation thermal history in the lunar regolith, size, and chemical composition. Based on the relationships presented in this paper, lunar impact glasses with compositions and sizes sufficient to have retained 90% of their radiogenic Ar during 750 Ma of cosmic ray exposure at time-integra...

  8. 40Ar/39Ar laser-probe dating of diamond inclusions from the Premier kimberlite

    International Nuclear Information System (INIS)

    Inclusions encapsulated by diamonds at the time of their formation provide a means for determining diamond crystallization ages and the chemistry of the surrounding upper mantle at that time. Sm-Nd studies of peridotitic inclusions, from Cretaceous-age kimberlites in southern Africa, suggest that the diamonds formed 3.3 Gyr ago. By contrast, eclogite-suite inclusions generally yield younger ages, sometimes approaching the time of kimberlite eruption. Here we report the results of 40Ar/39Ar laser-probe analyses of individual eclogitic clinopyroxene inclusions from Premier diamonds, which yield a mean age of 1,198±14 Myr. This age agrees well with Sm-Nd and 40Ar/39Ar analyses on similar Premier inclusions, and is indistinguishable from the inferred time of emplacement of the host kimberlite (1,150-1,230 Myr), which implies that diamond formation was essentially synchronous with kimberlite generation. The extrapolated non-radiogenic 40Ar/36Ar ratio of 334±102 is similar to the present-day atmospheric composition. This value is inconsistent with Sr and Nd isotopic signatures from Premier eclogite inclusions, which suggest a depleted mantle source (40Ar/36Ar>20,000). Pre-entrapment equilibration of the inclusions with an 36Ar-rich fluid is the most probable explanation for the low non-radiogenic (40Ar/36Ar) composition. (author)

  9. 40Ar/39Ar ages of lunar impact glasses: Relationships among Ar diffusivity, chemical composition, shape, and size

    Science.gov (United States)

    Zellner, N. E. B.; Delano, J. W.

    2015-07-01

    Lunar impact glasses, which are quenched melts produced during cratering events on the Moon, have the potential to provide not only compositional information about both the local and regional geology of the Moon but also information about the impact flux over time. We present in this paper the results of 73 new 40Ar/39Ar analyses of well-characterized, inclusion-free lunar impact glasses and demonstrate that size, shape, chemical composition, fraction of radiogenic 40Ar retained, and cosmic ray exposure (CRE) ages are important for 40Ar/39Ar investigations of these samples. Specifically, analyses of lunar impact glasses from the Apollo 14, 16, and 17 landing sites indicate that retention of radiogenic 40Ar is a strong function of post-formation thermal history in the lunar regolith, size, and chemical composition. This is because the Ar diffusion coefficient (at a constant temperature) is estimated to decrease by ∼3-4 orders of magnitude with an increasing fraction of non-bridging oxygens, X(NBO), over the compositional range of most lunar impact glasses with compositions from feldspathic to basaltic. Based on these relationships, lunar impact glasses with compositions and sizes sufficient to have retained ∼90% of their radiogenic Ar during 750 Ma of cosmic ray exposure at time-integrated temperatures of up to 290 K have been identified and are likely to have yielded reliable 40Ar/39Ar ages of formation. Additionally, ∼50% of the identified impact glass spheres have formation ages of ⩽500 Ma, while ∼75% of the identified lunar impact glass shards and spheres have ages of formation ⩽2000 Ma. Higher thermal stresses in lunar impact glasses quenched from hyperliquidus temperatures are considered the likely cause of poor survival of impact glass spheres, as well as the decreasing frequency of lunar impact glasses in general with increasing age. The observed age-frequency distribution of lunar impact glasses may reflect two processes: (i) diminished

  10. Contemporary root canal filling strategies

    OpenAIRE

    Moinzadeh, A.T.

    2016-01-01

    Currently, clinicians can choose from a wide range of root canal filling materials and techniques, some of which have been evaluated in this thesis. Methacrylate resin-based sealers suffer from polymerization shrinkage stresses. This limitation may partly be overcome by a two-step cementation procedure. This alternative placement technique results in an increase and homogenization of the adhesion of the material to intraradicular dentin. Subsequent research should aim at developing sealers wi...

  11. Rice Husk Filled Polymer Composites

    OpenAIRE

    Reza Arjmandi; Azman Hassan; Khaliq Majeed; Zainoha Zakaria

    2015-01-01

    Natural fibers from agricultural wastes are finding their importance in the polymer industry due to the many advantages such as their light weight, low cost and being environmentally friendly. Rice husk (RH) is a natural sheath that forms around rice grains during their growth. As a type of natural fiber obtained from agroindustrial waste, RH can be used as filler in composites materials in various polymer matrices. This review paper is aimed at highlighting previous works of RH filled polyme...

  12. Ar-40/Ar-39 laser-probe dating of diamond inclusions from the Premier kimberlite

    Science.gov (United States)

    Phillips, D.; Onstott, T. C.; Harris, J. W.

    1989-01-01

    The results of Ar-40/Ar-39 laser-probe analyses of individual eclogitic clinopyroxene inclusions from Premier diamonds are reported which yield a mean age of 1198 + or - 14 Myr. This age agrees well with Sm-Nd and Ar-40/Ar-39 analyses on similar Premier inclusions and is indistinguishable from the inferred time of emplacement of the host kimberlite, which implies that diamond formation was essentially synchronous with kimberlite generation. The extrapolated nonradiogenic Ar-40/Ar-36 ratio of 334 + or - 102 is similar to the present-day atmospheric composition. This value is inconsistent with Sr and Nd isotopic signatures from Premier eclogite inclusions, which suggest a depleted mantle source. Preentrapment equilibration of the inclusions with an Ar-36-rich fluid is the most probable explanation for the low nonradiogenic composition.

  13. 39Ar-40Ar systematics of two millimeter-sized rock fragments from Mare Crisium

    International Nuclear Information System (INIS)

    Two small fragments, L24B, a glass-rich agglutinate (1.9mg) and L24A, a fine-grained lithic fragment (9.4mg), from the Luna 24 landing site have been neutron irradiated for the purpose of 39Ar-40Ar dating. A fairly well-defined 39Ar-40Ar plateau age of 3.65+-0.12 AE was found for the larger fragment. After appropriate corrections the composition of the trapped and spallogenic Ar could be deciphered. The evolution of 38Arsub(sp)/37Ar showed that 660 m.y. and 500 m.y. were the most reliable exposure ages for L24A and L24B, respectively. The Ti contents of <=0.6% determined by gamma-counting prior to the Ar analysis indicate both fragments being associated with the group of low-Ti or even very low-Ti basalts. (Auth.)

  14. Energy resolution of gas ionization chamber for high-energy heavy ions

    Science.gov (United States)

    Sato, Yuki; Taketani, Atsushi; Fukuda, Naoki; Takeda, Hiroyuki; Kameda, Daisuke; Suzuki, Hiroshi; Shimizu, Yohei; Nishimura, Daiki; Fukuda, Mitsunori; Inabe, Naohito; Murakami, Hiroyuki; Yoshida, Koichi; Kubo, Toshiyuki

    2014-01-01

    The energy resolution is reported for high-energy heavy ions with energies of nearly 340 MeV/nucleon and was measured using a gas ionization chamber filled with a 90%Ar/10%CH4 gas mixture. We observed that the energy resolution is proportional to the inverse of the atomic number of incident ions and to the inverse-square-root of the gas thickness. These results are consistent with the Bethe-Bloch formula for the energy loss of charged particles and the Bohr expression for heavy ion energy straggling. In addition, the influence of high-energy δ-rays generated in the detector on the energy deposition is discussed.

  15. arXiv.org and Physics Education

    Science.gov (United States)

    Ramlo, Susan

    2007-09-01

    The website arXiv.org (pronounced archive) is a free online resource for full-text articles in the fields of physics, mathematics, computer science, nonlinear science, and quantitative biology that has existed for about 15 years. Available directly at http://www.arXiv.org, this e-print archive is searchable. As of Jan. 3, 2007, arXiv had open access to 401,226 e-prints in the topic areas. Those who sign up for an ID and password can also sign up for daily submission abstract emails for specific subject classes of arXiv, including physics education, physics and society, and history of physics. Founded and developed by Paul Ginsparg when he was at Los Alamos National Laboratory, arXiv's original name was the LANL preprint archive or xxx.lanl.gov. The location and name changed after Ginsparg moved to the physics department at Cornell University. Today, arXiv is hosted and operated by Cornell University library. Mirror sites for arXiv exist worldwide.2

  16. On mechanism of Ar(3p54p) states excitation in low-energy Ar-Ar collisions

    International Nuclear Information System (INIS)

    The present work is devoted to study of Ar(3p54p) states excitation in binary low-energy Ar-Ar collisions. The results of the experimental investigation of excitation cross sections of Ar I 4p'[l/2]1, 4p'[3/2]1, 4p'[3/2]2 and 4p[3/2]2 levels in the collision energy range from threshold up to 500 eV (cm) and degree of polarization for 4s[3/2]20-4p'[l/2]1 and 4s[3/2]20-4p[3/2]2 transitions in this energy range are represented.

  17. Ars Baltica-verkoston puheenjohtajuus Suomeen Risto Ruohoselle

    Index Scriptorium Estoniae

    1999-01-01

    1990. a. loodud võrgustiku Ars Baltica sekretariaat (Ars Baltica Contact Point & Communication Center) tuleb Kielist Tallinnasse Eesti kultuuriministeeriumi kuni aastani 2002 (Suur-Karja 23). Ars Baltica (ühendus)

  18. Instrumentation development for planetary in situ 40Ar/39Ar geochronology

    Science.gov (United States)

    Davidheiser-Kroll, B.; Morgan, L. E.; Munk, M.; Warner, N. H.; Gupta, S.; Slaybaugh, R.; Harkness, P.; Mark, D. F.

    2015-12-01

    The chronology of the Solar System, particularly the timing of formation of extraterrestrial bodies and their features, is a major outstanding problem in planetary science. Although various chronological methods for in situ geochronology have been proposed (e.g. Rb-Sr, K-Ar), and even applied (K-Ar, Farley et al., 2014), the reliability, accuracy, and applicability of the 40Ar/39Ar method makes it by far the most desirable chronometer for dating extraterrestrial bodies. The method however relies on the neutron irradiation of samples, and thus a neutron source. We will discuss the challenges and feasibility of deploying a passive neutron source to planetary surfaces for the in situ application of the 40Ar/39Ar chronometer. Requirements in generating and shielding neutrons, as well as analyzing samples are discussed, along with an exploration of limitations such as mass, power, and cost. Two potential solutions for the in situ extraterrestrial deployment of the 40Ar/39Ar method will be presented. Although this represents a challenging task, developing the technology to apply the 40Ar/39Ar method on planetary surfaces would represent a major advance towards constraining the timescale of solar system formation and evolution.

  19. 3c/4e [small sigma, Greek, circumflex]-type long-bonding competes with ω-bonding in noble-gas hydrides HNgY (Ng = He, Ne, Ar, Kr, Xe, Rn; Y = F, Cl, Br, I): a NBO/NRT perspective.

    Science.gov (United States)

    Zhang, Guiqiu; Li, Hong; Weinhold, Frank; Chen, Dezhan

    2016-03-01

    Noble-gas hydrides HNgY are frequently described as a single ionic form (H-Ng)(+)Y(-). We apply natural bond orbital (NBO) and natural resonance theory (NRT) analyses to a series of noble-gas hydrides HNgY (Ng = He, Ne, Ar, Kr, Xe, Rn; Y = F, Cl, Br, I) to gain quantitative insight into the resonance bonding of these hypervalent molecules. We find that each of the studied species should be better represented as a resonance hybrid of three leading resonance structures, namely, H-Ng(+ -):Y (I), H:(- +)Ng-Y (II), and H^Y (III), in which the "ω-bonded" structures I and II arise from the complementary donor-acceptor interactions nY → σ*HNg and nH → σ*NgY, while the "long-bond" ([small sigma, Greek, circumflex]-type) structure III arises from the nNg → [small sigma, Greek, circumflex]*HY/[small sigma, Greek, circumflex]HY interaction. The bonding for all of the studied molecules can be well described in terms of the continuously variable resonance weightings of 3c/4e ω-bonding and [small sigma, Greek, circumflex]-type long-bonding motifs. Furthermore, we find that the calculated bond orders satisfy a generalized form of "conservation of bond order" that incorporates both ω-bonding and long-bonding contributions [viz., (bHNg + bNgY) + bHY = bω-bonding + blong-bonding = 1]. Such "conservation" throughout the title series implies a competitive relationship between ω-bonding and [small sigma, Greek, circumflex]-type long-bonding, whose variations are found to depend in a chemically reasonable manner on the electronegativity of Y and the outer valence-shell character of the central Ng atom. The calculated bond orders are also found to exhibit chemically reasonable correlations with bond lengths, vibrational frequencies, and bond dissociation energies, in accord with Badger's rule and related empirical relationships. Overall, the results provide electronic principles and chemical insight that may prove useful in the rational design of noble-gas hydrides of

  20. Reaction of Li with O2 in the presence of He or Ar

    International Nuclear Information System (INIS)

    The reaction of Li with O2 in the presence of He or Ar was studied at a temperature near 150 0C for inert gas pressures between 29 and 1500 Torr. In both cases, the rate of loss of free Li atoms was linear with O2 partial pressure between approximately 0.003 and 1.3 Torr, but had a more complex dependence on inert gas pressure. In He, the reaction probably proceeded by means of the energy transfer mechanism where the dominant intermediate was LiO2*. The results in Ar are consistent with a reaction occurring through both the energy transfer mechanism in which LiO2* plays an important role and the bound intermediate complex mechanism where LiAr is the primary intermediate

  1. Ars ornata / Kadri Mälk

    Index Scriptorium Estoniae

    Mälk, Kadri, 1958-

    1998-01-01

    V rahvusvaheline ehtekunsti konverents 'Ars ornata Europeana' juuni lõpus Stockholmis. New Yorgis elava kuraatori Charon Kranseni ja prantsuse ehtekunstniku Christophe Burger' juhitud vestlusringidest. 1997. a. Pariisis loodud International Craft Design Association'ist (ICDA).

  2. "Ars Ornata" Mediterrania / Kadri Mälk

    Index Scriptorium Estoniae

    Mälk, Kadri, 1958-

    1999-01-01

    VI rahvusvaheline ehtekunstinäitus "Ars Ornata" juuni lõpus Barcelonas. Konverentsist, peanäitusest (osalejad Eestist), ehtekunstiõpetust andvast kõrgkoolist Escola Massana'st Barcelonas, õppejõude. Eesti ehtekunsti tulevikust.

  3. ARS 01 Helsingi Kiasmas / Tarmo Virki

    Index Scriptorium Estoniae

    Virki, Tarmo

    2001-01-01

    Helsingis Kiasmas avatud rahvusvahelisest kunstinäitusest ARS 01 alapealkirjaga "Avanevaid perspektiive", kus esines oma töödega ka Marko Mäetamm. Näituse raames toimuvast Santiago Sierra kunstiprojektist kodututega

  4. The mass of 32Ar and 33Ar for fundamental tests

    International Nuclear Information System (INIS)

    Masses of the short-lived radionuclides 32Ar (T1/2 = 98 ms) 33Ar (T1/2 = 173 ms) have been determined with the Penning trap mass spectrometer ISOLTRAP. Relative uncertainties of 6.0 x 10-8 (δm = 1.8 keV) and 1.4 x 10-8 (δm = 0.44 keV), respectively, have been achieved. At present, these new mass data serve as the most stringent test of the quadratic form of the isobaricmultiplet mass equation IMME. Furthermore, the improved accuracy for the mass of 32Ar yields a better constraint on scalar contributions to the weak interaction. New mass values have also been measured for 44Ar and 45Ar, and a 20σ deviation for 44Ar from the literature value was found and interpreted. (orig.)

  5. Dating blueschist metamorphism: a combined /sup 40/Ar//sup 39/Ar and electron microprobe approach

    Energy Technology Data Exchange (ETDEWEB)

    Sisson, V.B.; Onstott, T.C.

    1986-09-01

    /sup 40/Ar//sup 39/Ar and electron microprobe examination of blueschist samples from the Iceberg Lake schist, southern Alaska suggest that phengite inclusions are the source of /sup 40/Ar in crossite. Because such fine-grained inclusions may be susceptible to argon loss, caution should be exercised in interpreting K-Ar ages from this phase, and possibly other low-K amphiboles from blueschist suites. The estimated blocking temperature for phengite in the matrix (314/sup 0/ to 450/sup 0/C), however, is close to the estimated peak metamorphic temperatures (325/sup 0/ +- 50/sup 0/C), suggesting that phengite /sup 40/Ar//sup 39/Ar plateau dates may coincide closely with the time of blueschist metamorphism.

  6. Development of a laser detection system for Ar-39 and application to oceanographic mixing studies. Final report, October 1, 1980-March 31, 1984

    International Nuclear Information System (INIS)

    The report describes research aimed at developing an Ar-39 detector sensitive enough to be used in tracer studies of oceanic mixing, air-sea exchange processes, and deep-sea exchange processes. The concept of a generalized noble gas detector was accepted as the approach most likely to produce an Ar-39 detector. Reasons for the failure to achieve an Ar-39 detector and its future prospects are discussed

  7. The effects of retrograde reactions and of diffusion on 39Ar-40Ar ages of micas

    DEFF Research Database (Denmark)

    Allaz, Julien; Engi, Martin; Berger, Alfons;

    2011-01-01

    Effects of metamorphic reactions occurring during decompression were explored to understand their influence on 39Ar-40Ar ages of micas. Monometamorphic metasediments from the Lepontine Alps (Switzerland) were studied. Collected samples reached lower amphibolite facies during the Barrovian...... retrograde chlorite formation. We conclude that even very minor chloritisation of biotite is apparently a more effective parameter than temperature in resetting the Ar clock, as is the formation of plagioclase from paragonite decomposition. Multi-equilibrium thermobarometry is necessary to ensure that...

  8. Numerical simulation of mould filling process for pressure plate and valve handle in LFC

    Directory of Open Access Journals (Sweden)

    Jiang Junxia

    2010-11-01

    Full Text Available In lost foam casting (LFC, the distribution of polymer beads during the bead filling process is not uniform, and the collision between polymer beads determines the distribution of two-phase flow of gas and solid. The interaction between the gas and solid phases reveals as coupling effect of the force that gas exerts on particles or vice versa, or that among particles. The gas-solid flow in filling process is nonlinearity, which makes the coupling effect an essential point to carry out a simulation properly. Therefore, information of each particle’s motion is important for acquiring the law of filling process. In bead filling process, compressed air is pressed into mold cavity, and discharged from gas vent, creating a pressure difference between outer and inner space near the gas vent. This pressure difference directly changes the spatial distribution and motion trace of gas and solid phases. In this paper, Discrete Element Method (DEM and Computational Fluid Dynamics (CFD are employed to simulate the fluid dynamic character based on Newton’s Third Law of Motion. The simulation results of some casting products such as pressure plate and valve handle are compared with the result obtained from practical experiment in order to test the feasibility of DEM. The comparison shows that this DEM method can be a very promising tool in the mould filling simulation of beads’ movement.

  9. 7 CFR 58.923 - Filling containers.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Filling containers. 58.923 Section 58.923 Agriculture... Procedures § 58.923 Filling containers. (a) The filling of small containers with product shall be done in a sanitary manner. The containers shall not contaminate or detract from the quality of the product in any...

  10. Multiple Electron Capture Processes in Slow Collisions of Ar9+ Ions with Na Atoms

    Institute of Scientific and Technical Information of China (English)

    ZhuXiaolong; ShaShan; LiuHuiping; WeiBaoren; MaXinwen; WangZhengling; CaoShiping; QianDongbing; YangZhihu

    2003-01-01

    Slow collisions of highly charged ions with neutral atoms and molecules are of great importance in basic atomic collision physics, Recently, we built a new research facility for atomic physics at the Institute of Modern Physics. We report here the multiple electron transfer processes in collisions of Ar9+ with Na gas target at energy of 180 keV.

  11. 40Ar/39Ar age and thermal history of the Kirin chondrite

    International Nuclear Information System (INIS)

    The Kirin meteorite, a large (> 2800 kg) H5 chondrite, fell in Kirin Province, China in 1976. A sample from each of the two largest fragments (K-1. K-2) yield 40Ar/39Ar total fusion ages of 3.63 +- 0.02 b.y. and 2.78 +- 0.02 b.y. respectively. 40Ar/40Ar age spectra show typical diffusional argon loss profiles. Maximum apparent ages of 4.36 b.y. (K-1) and approx. 4.0 b.y. (K-2) are interpreted as possible minimum estimates for the age of crystallization of the parent body. (orig./ME)

  12. Ar-39-Ar-40 Evidence for Early Impact Events on the LL Parent Body

    Science.gov (United States)

    Dixon, E. T.; Bogard, D. D.; Garrison, D. H.; Rubin, A. E.

    2006-01-01

    We determined Ar-39-Ar-40 ages of eight LL chondrites, and one igneous inclusion from an LL chondrite, with the object of understanding the thermal history of the LL-chondrite parent body. The meteorites in this study have a range of petrographic types from LL3.3 to LL6, and shock stages from S1 to S4. These meteorites reveal a range of K-Ar ages from 23.66 to 24.50 Ga, and peak ages from 23.74 to 24.55 Ga. Significantly, three of the eight chondrites (LL4, 5, 6) have K-Ar ages of -4.27 Ga. One of these (MIL99301) preserves an Ar-39-Ar-40 age of 4.23 +/- 0.03 Ga from low-temperature extractions, and an older age of 4.52 +/- 0.08 Ga from the highest temperature extractions. In addition, an igneous-textured impact melt DOM85505,22 has a peak Ar-39-Ar-40 age of >= 4.27 Ga. We interpret these results as evidence for impact events that occurred at about 4.27 Ga on the LL parent body that produced local impact melts, reset the Ar-39-Ar-40 ages of some meteorites, and exhumed (or interred) others, resulting in a range of cooling ages. The somewhat younger peak age of 3.74 Ga from GR095658 (LL3.3) suggests an additional impact event close to timing of impact-reset ages of some other ordinary chondrites between 3.6-3.8 Ga. The results from MIL99301 suggest that some apparently unshocked (Sl) chondrites may have substantially reset Ar-39-Ar-40 ages. A previous petrographic investigation of MIL99301 suggested that reheating to temperatures less than or equal to type 4 petrographic conditions (600C) caused fractures in olivine to anneal, resulting in a low apparent shock stage of S1 (unshocked). The Ar-39-Ar-40 age spectrum of MIL99301 is consistent with this interpretation. Older ages from high-T extractions may date an earlier impact event at 4.52 +/- 0.08 Ga, whereas younger ages from lower-T extractions date a later impact event at 4.23 Ar-39-Ar-40 0.03 Ga that may have caused annealing of feldspar and olivine

  13. 40Ar - 39Ar dating of meteorites and the history of chondrite parent bodies

    International Nuclear Information System (INIS)

    The 40Ar-39Ar analyses of eleven ordinary chondrites and the unique meteorite Pontylyfni are presented. Results of previous 40Ar-39Ar age analyses have shown that the uncertainty in the calculated ages arises principally from the difficulties of interpretation of release patterns obtained from stepped heating experiments. For this reason considerable attention is paid to identifying the causes of complicating features in the age spectra. The ages obtained range from 4.52Ga to a lower limit of 4.38Ga and it is inferred that these date the time of cooling of the chondrites after formation and metamorphism. (author)

  14. NEW ACCURATE MEASUREMENT OF {sup 36}ArH{sup +} AND {sup 38}ArH{sup +} RO-VIBRATIONAL TRANSITIONS BY HIGH RESOLUTION IR ABSORPTION SPECTROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    Cueto, M.; Herrero, V. J.; Tanarro, I.; Doménech, J. L. [Molecular Physics Department, Instituto de Estructura de la Materia (IEM-CSIC), Serrano 123, E-28006 Madrid (Spain); Cernicharo, J. [Department of Astrophysics, CAB. INTA-CSIC. Crta Torrejón-Ajalvir Km 4, E-28850 Torrejón de Ardoz, Madrid (Spain); Barlow, M. J.; Swinyard, B. M., E-mail: jl.domenech@csic.es [Department of Physics and Astronomy, University College London. Gower Street, London WC1E 6BT (United Kingdom)

    2014-03-01

    The protonated argon ion, {sup 36}ArH{sup +}, was recently identified in the Crab Nebula from Herschel spectra. Given the atmospheric opacity at the frequency of its J = 1-0 and J = 2-1 rotational transitions (617.5 and 1234.6 GHz, respectively), and the current lack of appropriate space observatories after the recent end of the Herschel mission, future studies on this molecule will rely on mid-infrared observations. We report on accurate wavenumber measurements of {sup 36}ArH{sup +} and {sup 38}ArH{sup +} rotation-vibration transitions in the v = 1-0 band in the range 4.1-3.7 μm (2450-2715 cm{sup –1}). The wavenumbers of the R(0) transitions of the v = 1-0 band are 2612.50135 ± 0.00033 and 2610.70177 ± 0.00042 cm{sup –1} (±3σ) for {sup 36}ArH{sup +} and {sup 38}ArH{sup +}, respectively. The calculated opacity for a gas thermalized at a temperature of 100 K and with a linewidth of 1 km s{sup –1} of the R(0) line is 1.6 × 10{sup –15} × N({sup 36}ArH{sup +}). For column densities of {sup 36}ArH{sup +} larger than 1 × 10{sup 13} cm{sup –2}, significant absorption by the R(0) line can be expected against bright mid-IR sources.

  15. 40Ar/39Ar ages in deformed potassium feldspar: evidence of microstructural control on Ar isotope systematics

    Science.gov (United States)

    Reddy, Steven M.; Potts, Graham J.; Kelley, Simon P.

    2001-05-01

    Detailed field and microstructural studies have been combined with high spatial resolution ultraviolet laser 40Ar/39Ar dating of naturally deformed K-feldspar to investigate the direct relationship between deformation-related microstructure and Ar isotope systematics. The sample studied is a ~1,000 Ma Torridonian arkose from Skye, Scotland, that contains detrital feldspars previously metamorphosed at amphibolite-facies conditions ~1,700 Ma. The sample was subsequently deformed ~430 Ma ago during Caledonian orogenesis. The form and distribution of deformation-induced microstructures within three different feldspar clasts has been mapped using atomic number contrast and orientation contrast imaging, at a range of scales, to identify intragrain variations in composition and lattice orientation. These variations have been related to thin section and regional structural data to provide a well-constrained deformation history for the feldspar clasts. One hundred and forty-three in-situ 40Ar/39Ar analyses measured using ultraviolet laser ablation record a range of apparent ages (317-1030 Ma). The K-feldspar showing the least strain records the greatest range of apparent ages from 420-1,030 Ma, with the oldest apparent ages being found close to the centre of the feldspar away from fractures and the detrital grain boundary. The most deformed K-feldspar yields the youngest apparent ages (317-453 Ma) but there is no spatial relationship between apparent age and the detrital grain boundary. Within this feldspar, the oldest apparent ages are recorded from orientation domain boundaries and fracture surfaces where an excess or trapped 40Ar component resides. Orientation contrast images at a similar scale to the Ar analyses illustrate a significant deformation-related microstructural difference between the feldspars and we conclude that deformation plays a significant role in controlling Ar systematics of feldspars at both the inter- and intragrain scales even at relatively low

  16. Effect of expansive fillings on fracture seepage

    Institute of Scientific and Technical Information of China (English)

    CHEN Jin-gang; YANG Jun-li; ZHANG Jing-fei

    2009-01-01

    Based on an investigation of the damage process of fractures filled with expansion media, samples of filling media col-lected on the spot, were obtained. The physical water properties of fracture fillings were tested by a WZ-2 type Dilatometer. Given our test results of the hydrated properties of fracture fillings and the mechanical parameters of altered rock mass collected from the Daye Iron Mine and comparisons between the expansion stress of fracture fillings and mechanical parameters of altered rock mass, the effects of the mechanical response of fillings on fracture seepage are discussed. The results show that the ratio of filling swell pressure to tensile strength of altered rock specimen varied between 11.79 and 36.77 and the ratio of filling swell pressure to shear strength of these rock specimen ranged from 72.11 to 171.18. Therefore, fillings have an important effect on fracture seepage, and the effect of deformation of the fracture caused by swell pressure of the filling mechanics cannot be ignored either. The multiple hydraulic coupling effects of fillings on the impact of fracture permeability are discussed according to theoretical analyses. It is shown that the effect of expansion of fracture fillings greatly affects the deformation of altered rock masses. Both tensile effect and shear effect produced by fracture fillings greatly increase the permeability of fractures. The plastic and liquefaction effects of frac-ture fillings also improve the permeability of fractures. On the basis of this analysis, a mechanical seepage model of filled fracture is established.

  17. Electron Cyclotron Resonance-Reactive Ion Etching of III-V Semiconductors by Cyclic Injection of CH4/H2/Ar and O2 with Constant Ar Flow

    Science.gov (United States)

    Haneji, Nobuo; Segami, Goh; Ide, Tomoyoshi; Suzuki, Tatsuya; Arakawa, Taro; Tada, Kunio; Shimogaki, Yukihiro; Nakano, Yoshiaki

    2003-06-01

    Electron cyclotron resonance-reactive ion etching (ECR-RIE) is very useful for fabricating semiconductor photonic devices and integrated circuits (PICs). The mixture gas of CH4/H2 is used for etching III-V semiconductors, but the carbon polymer film deposited on the surface during the etching process presents some problems. Thus, the polymer film must be ashed off using an O2 plasma. We introduced the cyclic injection of CH4/H2/Ar and O2 to ECR-RIE, and demonstrated that it was very useful for etching of InP. However, compound semiconductors containing Al (e.g., AlGaAs and InAlAs) react with oxygen and an alumina layer is formed, which cannot be etched by CH4/H2 etching. Therefore, we used a new cyclic etching process with constant Ar flow in the chamber to remove this alumina layer by Ar ion etching, and obtained good results for etching rate and surface morphology for the compound semiconductors containing Al. We also proposed a suitable combination of three cyclic etching procedures (continuous etching, cyclic etching without constant Ar flow and cyclic etching with constant Ar flow) for etching the multilayer heterostructure of III-V semiconductors including InP and/or compound semiconductors containing Al.

  18. Using ICD for structural analysis of clusters: a case study on NeAr clusters

    International Nuclear Information System (INIS)

    We present a method to utilize interatomic Coulombic decay (ICD) to retrieve information about the mean geometric structures of heteronuclear clusters. It is based on observation and modelling of competing ICD channels, which involve the same initial vacancy, but energetically different final states with vacancies in different components of the cluster. Using binary rare gas clusters of Ne and Ar as an example, we measure the relative intensity of ICD into (Ne+)2 and Ne+Ar+ final states with spectroscopically well separated ICD peaks. We compare in detail the experimental ratios of the Ne–Ne and Ne–Ar ICD contributions and their positions and widths to values calculated for a diverse set of possible structures. We conclude that NeAr clusters exhibit a core–shell structure with an argon core surrounded by complete neon shells and, possibly, further an incomplete shell of neon atoms for the experimental conditions investigated. Our analysis allows one to differentiate between clusters of similar size and stochiometric Ar content, but different internal structure. We find evidence for ICD of Ne 2s−1, producing Ar+ vacancies in the second coordination shell of the initial site. (paper)

  19. Effect of gas pressure on ionization of ambient gas

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An Nd: YAG pulsed laser (145 mJ) was used to ablate aluminum target and Ar was used as protecting gas. Time-and space-resolved spectra of the plasmas under pressure 100 Pa, 1 kPa, 10 kPa and 100 kPa were acquired with time- and space-resolved technique. The characteristics of the plasma radiating under each pressure were briefly described, and the laws of Ar characteristical radiaton were analyzed in detail. Based on the profile of Ar characteristical radiation under these pressure, the relation between protecting gas pressure and its ionization was briefly discussed, and explained with quantum theory. Farther more, the mechanism of ambient gas ionization was investigated. As the result, it was suggested that the main mechanism inducing protecting gas to ionize should be the absorption of the plasma continuum radiation by the gas.

  20. Modified bunch filling scheme for Indus-2

    International Nuclear Information System (INIS)

    Currently Indus-2 is operated with all bunches filled mode. It may be required to fill the ring with different bunch filling patterns in future as per requirements of the users and also to mitigate the problems of ion trapping and beam instabilities. In Indus-2 one can store beam current in maximum of 291 bunches. A bunch-filling scheme has been evolved in which, it is possible to fill Indus-2 with different filling patterns. In the earlier scheme, three patterns of bunch filling are proposed namely all bunches, three symmetric bunches and a single bunch. In this scheme there is problem of bunch overlapping in the buckets, if more than one bunch is extracted from the booster. In the new scheme, a formulation has been derive to avoid the overlapping of bunches. (author)

  1. Application of Cl2/BCl3/Ar Plasma Treatment in the Improvement of Ti/Al/Mo/Au Ohmic Contacts

    Directory of Open Access Journals (Sweden)

    Jacek Gryglewicz

    2016-01-01

    Full Text Available Significant improvement of Ti/Al/Mo/Au ohmic contacts deposited on previously Cl2/BCl3/Ar plasma treated surface was observed. The standard deviation of contact resistance was crucially reduced due to the incorporation of Cl2/BCl3/Ar plasma treatment. The Cl2:BCl3:Ar gas mixture was used in order to thin the top of AlGaN layer prior to deposition of Ti/Al/Mo/Au ohmic contacts. The surface morphology of AlGaN was investigated using scanning electron microscopy and atomic force microscopy. TLM measurements revealed a consequential decrease of contact resistivity.

  2. ArDroneXT - Ar.Drone 2 eXTension for swarming and service hosting

    OpenAIRE

    Autefage, Vincent; Chaumette, Serge

    2013-01-01

    This report explains how to upgrade an Ar.Drone 2 for swarming and services hosting. In other words, it gives the technical information required to easily create a swarm of Ar.Drone 2 sharing a Wi-Fi network. Moreover, it describes the process to install new services and applications on the drone.

  3. A Refined Astronomically Calibrated 40Ar/39Ar Age for Fish Canyon Sanidine

    DEFF Research Database (Denmark)

    Rivera, Tiffany; Storey, Michael; Zeeden, Christian; Hilgen, Frederik; Kuiper, Klaudia

    sanidine age of 0.7674±0.0022 Ma (2σ, external errors) is indistinguishable from the ID-TIMS U/Pb zircon age (0.7671±0.0019 Ma). The consistency between the astronomically calibrated 40Ar/39Ar sanidine age and U/Pb zircon age for this Quaternary unit suggests that agreement between these two radio...

  4. High radon levels in subterranean environments: monitoring and technical criteria to ensure human safety (case of Castañar cave, Spain).

    Science.gov (United States)

    Alvarez-Gallego, Miriam; Garcia-Anton, Elena; Fernandez-Cortes, Angel; Cuezva, Soledad; Sanchez-Moral, Sergio

    2015-07-01

    Castañar cave contains the highest radon gas ((222)Rn) concentration in Spain with an annual average of 31.9 kBq m(-)(3). Seasonal variations with summer minimums and maximum values in fall were recorded. The reduction of air-filled porosity of soil and rock by condensation or rainfalls hides the radon exchange by gas diffusion, determining this seasonal stair-step pattern of the radon activity concentration in underground air. The effective total dose and the maximum hours permitted have been evaluated for the guides and public safety with a highly detailed radon measurement along 2011 and 2012. A network of 12 passive detectors (kodalphas) has been installed, as well as, two radon continuous monitoring in the most interesting geological sites of the subterranean environment. A follow up of the recommended time (max. 50 min) inside the underground environment has been analysed since the reopen to public visitors for not surpassing the legal maximum effective dose for tourists and guides. Results shown that public visitors would receive in fall a 12.1% of the total effective dose permitted per visit, whereas in summer it is reduced to 8.6%, while the cave guide received a total effective dose of 6.41 mSv in four months. The spatial radon maps allow defining the most suitable touristic paths according to the radon concentration distribution and therefore, appropriate fall and summer touristic paths are recommended. PMID:25863322

  5. AR-40 AR-39 Age of an Impact-Melt Lithology in DHOFAR 961

    Science.gov (United States)

    Frasl, B.; Cohen, B. A.; Li, Z.-H.; Jolliff, B.; Korotev, R.; Zeigler, R.

    2016-01-01

    The South Pole-Aitken (SPA) basin is the stratigraphically oldest identifiable lunar basin and is therefore one of the most important targets for absolute age-dating to help understand whether ancient lunar bombardment history smoothly declined or was punctuated by a cataclysm. The SPA basin also has another convenient property, a geochemically distinct interior, unobscured by extensive mare basalt fill. A case has been made for the possible origin of the Dhofar 961 lunar meteorite in the South Pole-Aitken (SPA) basin, based on comparing its composition with Lunar Prospector gamma-ray data for the interior of the SPA basin. Dhofar 961 contains several different impact-melt (IM) lithologies. Jolliff et al. described two classes of mafic impact-melt lithologies, one dominated by olivine (Lithology A) and the other by plagioclase (An 95-96.5) (Lithology B). Broad-beam analyses of these lithologies yielded (is) approximately 14.0 wt% FeO, 11.7 wt% MgO, and 15.4 wt% Al2O3. Lithologies A and B differ by approximately 2.5% Al2O3, 1.5% FeO and 1.5% MgO, consistent with the occurrence of olivine phenocrysts in A and plagioclase clasts in B. Both lithologies are considerably more mafic than the Apollo mafic impact-melt breccias, corresponding to olivine gabbronorite. Joy et al. used U-Pb dating to investigate phosphate fragments in the Dhofar 961 matrix and impact-melt clasts. Matrix phosphates have 4.34 to 4 Ga ages, consistent with ancient KREEP-driven magmatic episodes and Pre-Nectarian ((is) greater than 3.92 Ga). Phosphates found within Dhofar 961 crystalline impact melt breccia clasts range from 4.26 to 3.89 Ga, potentially recording events throughout the basin forming epoch of lunar history. The youngest reset ages in the Dhofar 961 sample represent an upper limit for the time of formation of the meteorite. Joy et al suggested this age represents the final impact that mixed and consolidated several generations of precursor rocks into the Dhofar meteorite group

  6. K/Ar ages from basal gneiss region

    International Nuclear Information System (INIS)

    K/Ar and 40Ar/39Ar geochronology of minerals from the Stadlandet region, Norway, is complicated by the presence of excess 40Ar in many samples. There is a correlation between excess 40Ar concentration and textural occurrence of samples. Amphiboles and micas closely accociated with eclogite pods are likely to contain significant concentrations of excess 40Ar, while samples from the country rocks are not. K/Ar and 40Ar/39Ar ages for hornblende from the country rocks suggest that post-metamorphic cooling through 5000C occured about 410 Ma ago, shortly after eclogite formation. Biotites containing no excess 40Ar cooled through 3000C about 370 Ma ago. A post-metamorphic cooling rate of about 50C/Ma can be inferred

  7. Ar-41 measurements and nuclear emergency preparedness

    International Nuclear Information System (INIS)

    During the early phase of an emergency is necessary to confirm the release of radioactivity predictions made by the operator of the nuclear plant. In this context, it has begun measuring Ar-41 in the vicinity of a research reactor. Since the Ar-41 is produced in the reactor, it has been studied as a good way to validate the air dispersion model used in nuclear emergencies and to develop a method to improve the characterization of the release. For this latter purpose a pilot experiment was conducted to determine computational and experimental methods, the flux of 1.29 MeV of Ar-41 and compared to evaluate the accuracy of the assessments made. This paper describes meteorological forecasting systems used in the experiment, the estimate of the stability class and the concentration of nuclides using a calculation code developed by the ARN, as well as the methodology and equipment used for measurement in the field. (authors)

  8. Improved Ar(II) transition probabilities

    OpenAIRE

    Danzmann, K.; de Kock, M

    1986-01-01

    Precise Ar(II) branching ratios have been measured on a high current hollow cathode with a 1-m Fourier transform spectrometer. Absolute transition probabilities for 11 Ar(II) lines were calculated from these branching ratios and lifetime measurements published by Mohamed et al. For the prominent 4806 Å line, the present result is Aik = 7.12×107s-1 ±2.8%, which is in excellent agreement with recent literature data derived from pure argon diagnostics, two-wavelength-interferometry, and Hβ-diagn...

  9. Online Scene Modeling for Interactive AR Applications

    OpenAIRE

    Yoo, Jaesang; Cho, Kyusung; Jung, Jinki; Yang, Hyun S.

    2010-01-01

    Augmented reality applications require 3D model of environment to provide even more realistic experience. Unfortunately, however, most of researches on 3D modeling have been restricted to an offline process up to now, which conflicts with characteristics of AR such as realtime and online experience. In addition, it is barely possible not only to generate 3D model of whole world in advance but also trasfer the burden of 3D model generation to a user, which limits the usability of AR. Thus, it ...

  10. AR-扩增实境

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    1、什么是AR-扩增实境?AR-扩增实境(Augmented Reality,简称AR),简单地说,就是把虚拟的物体和现实的场景进行嫁接。这是一种实时地计算摄影机影像的位置及角度并加上相应图像的技术,这种技术的目标是在屏幕上把虚拟世界套在现实世界并进行互动。

  11. Penning ionization : In benzene · Ar and fluorobenzene · Ar van der waals molecules and in collisions of benzene with metastable Ar atoms

    Science.gov (United States)

    Rühl, E.; Bisling, P.; Brutschy, B.; Beckmann, K.; Leisen, O.; Morgner, H.

    1986-08-01

    The photoion efficiency curves of the van der Waals complexes benzene ·Ar (Bz·Ar) and fluorobenzene·Ar (Fb·Ar) exhibit sharp resonances, which correspond to excitation to the Ar 2P 3/24s and 2P 1/24s resonance states. The peaks are redshifted relative to their asymptotic values (Bz·Ar, Δ E = -70 ± 10 meV; Fb·Ar, Δ E = -40 ± 10 meV). These findings are supported by electron spectroscopy studies of the Penning ionization of benzene by state-selected metastable Ar ( 3p 2, 3p 0) atoms. Strong evidence is presented that Penning ionization is the process observed in both cases.

  12. Dielectric-filled radiofrequency linacs

    International Nuclear Information System (INIS)

    High current, high brightness electron beam accelerators promise to open up dramatic new applications. Linear induction accelerators are currently viewed as the appropriate technology for these applications. A concept by Humphries and Hwang may permit radiofrequency accelerators to fulfill the same functions with greater simplicity and enhanced flexibility. This concept involves the replacement of vacuum rf cavities with dielectric filled ones. Simple analysis indicates that the resonant frequencies are reduced by a factor of (ε0/ε)1/2 while the stored energy is increased by ε/ε0. For a high dielectric constant like water, this factor can approach 80. A series of numerical calculations of simple pill-box cavities was performed. Eigenfunctions and resonant frequencies for a full system configuration, including dielectric material, vacuum beamline, and a ceramic window separating the two have been computed. These calculations are compared with the results of a small experimental cavity which have been constructed and operated. Low power tests show excellent agreement. (author). 4 figs., 8 refs

  13. Dedicated composite fillings − inlays

    Directory of Open Access Journals (Sweden)

    Šaulić Slobodan

    2003-01-01

    Full Text Available Background. The aim of the study was to evaluate the quality and persistance of esthetics of dedicated inlay by clinical methods. Methods. The paper reviews the clinical significance and technique of preparing particular composite inlays before and after the construction of the metallic framework partial denture. On the basis of indications the total of 30 inlays were placed into cavities under relatively dry working conditions. Six, twelve eighteen and twenty-four months after the placement of filling, control check-up was carried out by Ryge criteria. Results. After two years marginal discoloration as well as the change of the colour occured in 3.3% of inlays. There was neither detectable secondary caries, nor the symtoms of pulpal damage. The requirements to be fulfilled concerning the composite materials in order that they can be implemented for this purpose, were also discussed. Conclusion. From the clinical point of view, purpouse inlays from Herculite XRV lab C8B in combination with Opti Bond System and composite cement Porcelite Dual Cure showed high functional and esthetic values in the observational period of two years.

  14. NUMERICAL SIMULATION OF CASTING'S MOLD FILLING PROCESS

    Institute of Scientific and Technical Information of China (English)

    J.X. Zhou; R.X. Liu; L.L. Chen; D.M. Liao; H.S. Wei

    2005-01-01

    Numerical simulation of casting's mold filling process is the main and the most important aspect of the foundry CAE technology. But it is time-consuming; it may take dozens of hours or several days. While with the development of computer hardware, numerical simulation of casting' s mold filling process has made rapid progress. The simulation results, therefore, have become more and more practical. This study tries to find some clues of the computational time of mold filling process. Firstly, this paper introduces mathematic model and the basic route of numerical simulation of casting's mold filling process. Then the computational time of mold filling process has been carefully studied, and some new and useful results have been gained from the study of the computational time. Finally, this paper has given some real applications of numerical simulation of casting's mold filling process.

  15. Comparative 40Ar/39Ar and K-Ar dating of illite-type clay minerals: A tentative explanation for age identities and differences

    Science.gov (United States)

    Clauer, Norbert; Zwingmann, Horst; Liewig, Nicole; Wendling, Raymond

    2012-10-01

    The 40K/40Ar (K-Ar) and 40Ar/39Ar dating methods are applied here to the same, very small, micrometric illite-type particles that crystallized under low-temperature (samples with a total of fifteen size fractions from advantages, such as the plateaus obtained by incremental step heating of the various size fractions, even if not translatable straight as ages of the illite populations; they allow identification of two generations of authigenic illite that formed at about 200 and 175 Ma, and one detrital generation. However, 40Ar/39Ar dating of clay minerals remains challenging as technical factors, such as the non-standardized encapsulation, may have potential unexpected effects. Both dating methods have their limitations: (1) K-Ar dating requires relatively large samples (ca. 10-20 mg) incurring potential sample homogeneity problems, with two aliquots required for K and Ar analysis for an age determination, also inducing a higher analytical uncertainty; (2) an identified drawback of 40Ar/39Ar dating is Ar recoil and therefore potential loss that occurs during neutronic creation of 39Ar from 39K, mostly in the finer mineral particles. If all the recoiled 39Ar is redistributed into adjacent grains/minerals, the final 40Ar/39Ar age of the analyzed size fraction remains theoretically identical, but it is not systematic in clay-type material. The finest grain sizes (e.g., convenient and straightforward use supported by a standardized and well-controlled technical approach. The present comparison of the two Ar-dating methods as applied to clay material shows that neither method is presently outdated, and that they are even of reciprocal use. Both methods have distinct application fields in clay geochronology and complementary application fields in clay crystallography.

  16. Collective dipole response of proton-rich nuclei 32Ar and 34Ar

    International Nuclear Information System (INIS)

    The earlier observation of low-lying dipole strength in neutron rich nuclei and its interpretation with respect to basic nuclear properties (symmetry energy, skin thickness) initiated the investigation of this phenomenon in proton-rich nuclei. Macroscopically this strength could be explained with the resonant dipole oscillation of a proton skin against the isospin-symmetric core. For nuclei like 32Ar the occurrence of pronounced dipole strength is predicted in the low-energy region between 8-10 MeV excitation energy. For the 34Ar the pygmy strength is expected to drop sharply and vanish entirely for the N=Z nucleus 36Ar. The experiment S327 has been performed in August 2008 at the GSI Darmstadt in Cave C using the LAND reaction setup. Fragmentation of a 800 A MeV primary 36Ar beam on a Be target was used to produce the radioactive isotopes 34Ar and 32Ar. After passing the FRS (Fragment Separator) the ions impinged on a Pb target. The dipole response is observed using the Coulomb excitation method in inverse kinematics. The concept and the experimental method will be shown in the context of the underlying physics case in 32,34Ar.

  17. Modification of stearic acid in Ar and Ar-O2 pulsed DC discharges

    International Nuclear Information System (INIS)

    Stearic acid (C18H36O2) was treated into Ar and Ar-O2(10%) pulsed DC discharge created by a cathode-anode confined system. The samples were placed at the floating potential. The results show that the mass variation of the stearic acid samples after Ar-O2 plasma exposure is more important than the pure Ar plasma treatments. This comportment demonstrate that the oxygen actives species (O and O2 in all states) strongly enhance the etching process with regards to A* species, regardless of their concentration. After treatment by Ar and Ar-O2 plasma, analyses by X-ray diffraction show a significant structural modification of the samples surface, utilizing Ar-O2 plasma the modification was more pronounced. The chemical composition evolution shows that the acid function is etched preferentially in the beginning of the treatment (about 5 min) and that after 10 min the carbonic chains seems to be functionalized by oxygen. (author)

  18. Explicit Dehn filling and Heegaard splittings

    CERN Document Server

    Futer, David

    2012-01-01

    We prove an explicit, quantitative criterion that ensures the Heegaard surfaces in Dehn fillings behave "as expected." Given a cusped hyperbolic manifold X, and a Dehn filling whose meridian and longitude curves are longer than 2pi(2g-1), we show that every genus g Heegaard splitting of the filled manifold comes from a splitting of the original manifold X. The analogous statement holds for fillings of multiple boundary tori. This gives an effective version of a theorem of Moriah-Rubinstein and Rieck-Sedgwick.

  19. Age of Cu-Au mineralisation, Cloncurry district, eastern Mt Isa Inlier, Queensland, as determined by 40Ar/39Ar dating

    International Nuclear Information System (INIS)

    The 40Ar/39Ar dating of alteration biotite. muscovite and amphibole from a number of post-peak metamorphic Cu-Au deposits and alteration systems in the Cloncurry district. north Queensland has determined the timing of mineralisation and hydrothermal activity. Alteration biotite from the Ernest Henry Cu-Au, Starra Au-Cu, and Mt Elliott Cu-Au deposits, sericite associated with hematite breccias in the Wimberu Granite, muscovite from an albitite pipe that intrudes the Gilded Rose Breccia. And sericite from a granitoid near the Osborne Cu-Au deposit. yield ages which are broadly contemporaneous with the late ca 1510-1485 Ma phases of the Williams and Naraku Batholiths. Hornblende and biotite alteration, which pre-date Cu-Au mineralisation at Osborne. give a maximum age of ca 1540 Ma for the deposit. which is also a probable minimum age for peak metamorphism. Metamorphic minerals from the vicinity of Osborne yield dates which are significantly older (ca 1590-1570 Ma) than those from the hydrothermal phases. Dating by the K-Ar method of red. Hematitic K-feldspars which are regionally common in the Cloncurry district was not effective as the mineral yields ages up to 300 million years younger than coexisting alteration sericite. The 40Ar/39Ar age spectra obtained from most hydrothermal phases in the Eastern Fold Belt. Mt Isa Inlier commonly contain flat parts which comprise a large proportion of the released gas and are indicative of rapid cooling through the temperature of partial closure to Ar diffusion for the respective minerals. Copyright (1998) Blackwell Science Asia

  20. Potassium Isotopic Compositions of NIST Potassium Standards and 40Ar/39Ar Mineral Standards

    Science.gov (United States)

    Morgan, Leah; Tappa, Mike; Ellam, Rob; Mark, Darren; Higgins, John; Simon, Justin I.

    2013-01-01

    Knowledge of the isotopic ratios of standards, spikes, and reference materials is fundamental to the accuracy of many geochronological methods. For example, the 238U/235U ratio relevant to U-Pb geochronology was recently re-determined [1] and shown to differ significantly from the previously accepted value employed during age determinations. These underlying values are fundamental to accurate age calculations in many isotopic systems, and uncertainty in these values can represent a significant (and often unrecognized) portion of the uncertainty budget for determined ages. The potassium isotopic composition of mineral standards, or neutron flux monitors, is a critical, but often overlooked component in the calculation of K-Ar and 40Ar/39Ar ages. It is currently assumed that all terrestrial materials have abundances indistinguishable from that of NIST SRM 985 [2]; this is apparently a reasonable assumption at the 0.25per mille level (1s) [3]. The 40Ar/39Ar method further relies on the assumption that standards and samples (including primary and secondary standards) have indistinguishable 40K/39K values. We will present data establishing the potassium isotopic compositions of NIST isotopic K SRM 985, elemental K SRM 999b, and 40Ar/39Ar biotite mineral standard GA1550 (sample MD-2). Stable isotopic compositions (41K/39K) were measured by the peak shoulder method with high resolution MC-ICP-MS (Thermo Scientific NEPTUNE Plus), using the accepted value of NIST isotopic SRM 985 [2] for fractionation [4] corrections [5]. 40K abundances were measured by TIMS (Thermo Scientific TRITON), using 41K/39K values from ICP-MS measurements (or, for SRM 985, values from [2]) for internal fractionation corrections. Collectively these data represent an important step towards a metrologically traceable calibration of 40K concentrations in primary 40Ar/39Ar mineral standards and improve uncertainties by ca. an order of magnitude in the potassium isotopic compositions of standards.

  1. Plasma chemistry in an atmospheric pressure Ar/NH3 dielectric barrier discharge

    DEFF Research Database (Denmark)

    Fateev, A.; Leipold, F.; Kusano, Y.;

    2005-01-01

    An atmospheric pressure dielectric barrier discharge (DBD) in Ar/NH3 (0.1 - 10%) mixtures with a parallel plate electrode geometry was studied. The plasma was investigated by emission and absorption spectroscopy in the UV spectral range. Discharge current and voltage were measured as well. UV...... absorption spectroscopy was also employed for the detection of stable products in the exhaust gas. To clarify the different processes for ammonia decomposition, N-2(2 - 10%) was added to the plasma. Modeling of the chemical kinetics in an Ar/NH3 plasma was performed as well. The dominant stable products of...... an atmospheric pressure Ar/NH3 DBD are H-2, N-2 and N2H4. The hydrazine (N2H4) concentration in the plasma and in the exhaust gases at various ammonia concentrations and different discharge powers was measured. Thermal N2H4 decomposition into NH2 radicals may be used for NOx reduction processes....

  2. Subterranean production of neutrons, $^{39}$Ar and $^{21}$Ne: Rates and uncertainties

    CERN Document Server

    Šrámek, Ondřej; McDonough, William F; Mukhopadhyay, Sujoy; Peterson, R J

    2015-01-01

    Accurate understanding of the subsurface production of radionuclide $^{39}$Ar rate is necessary for argon dating techniques and noble gas geochemistry of the shallow and the deep Earth, and is also of interest to the WIMP dark matter experimental particle physics community. Our new calculations of subsurface production of neutrons, $^{21}$Ne, and $^{39}$Ar take advantage of the best available tools of nuclear physics to obtain reaction cross sections and spectra (TALYS) and to evaluate neutron propagation in rock (MCNP6). We discuss our method and results in relation to previous studies and show the relative importance of various neutron, $^{21}$Ne, and $^{39}$Ar nucleogenic production channels. Uncertainty in nuclear reaction cross sections, which is the major contributor to overall calculation uncertainty, is estimated from variability in existing experimental and library data. Depending on selected rock composition, on the order of $10^7$-$10^{10}$ {\\alpha} particles are produced in one kilogram of rock pe...

  3. A study of the 40Ar(p,γ)41K reaction

    International Nuclear Information System (INIS)

    This experiment has been undertaken to gain information on 40Ar(p,γ)41K resonances and the 41K nucleus. The targets were prepared by implanting high purity argon gas into tantalum backings. Proton beams were produced by the 2,6 MeV Van de Graaff accelerator at the Potchefstroom University for CHE. The spread in beam energy was 1 keV at 1 MeV. The excitation curve for the 40Ar(p,γ)41K reaction has been measured in the energy range 0,9 MeV 40Ar(p,γ)41K resonances. The gamma decay of these resonances have been studied utilizing a large Ge(Li) detector. The uncertain 4.03→2.32 and 4.75→1.70 keV transitions are confirmed. 9 figs., 30 refs., 5 tabs

  4. Hazard evaluation for 244-AR vault facility

    International Nuclear Information System (INIS)

    This document presents the results of a hazard identification and evaluation performed on the 244-AR Vault Facility to close a USQ (USQ No. TF-98-0785, Potential Inadequacy in Authorization Basis (PIAB): To Evaluate Miscellaneous Facilities Listed in HNF-2503 And Not Addressed In The TWRS Authorization Basis) that was generated as part of an evaluation of inactive TWRS facilities

  5. "ARS 01", perspektiivide avamine / Helen Kivisoo

    Index Scriptorium Estoniae

    Kivisoo, Helen

    2001-01-01

    30. IX 2001-20. I 2002 Kiasmas kuuendat korda toimuvast rahvusvahelisest näitusest "ARS", kus Eestist osaleb Marko Mäetamm. Kuraatorid Tuula Arkio, Maaretta Jaukkuri, Patrik Nyberg, Jari-Pekka Vanhala. Teemaks "kolmas ruum". Näituse kajastamisest.

  6. Lignocellulosic Biofuels: Bioenergy Research at ARS

    Science.gov (United States)

    The growth and long-term viability of bioenergy production in the Nation are impeded by a number of technical and commercial barriers. Agricultural Research Service (ARS) addresses technical barriers and does so by leveraging its strengths and unique capabilities to (1) pursue technical barriers th...

  7. Ionization of Argon n=2 (Ar+9 to Ar+16) by a 'relativistic' laser field

    International Nuclear Information System (INIS)

    The high field photoionization cross sections for the (n=2) shell of argon were measured with pulsed 800 nm radiation (27±5 fs duration) at an intensity of 1.5x1019 W/cm2±1x1019 W/cm2. The pondermotive energy for an electron at these field intensities is approximately 1 MeV. The best agreement with a calculated AC tunneling model was at an intensity of 0.6x1019 W/cm2. The difference between experimental and calculated relative charge state yields is less than an order of magnitude for Ar+9 to Ar+14 and Ar+16

  8. A compilation of 40Ar-39 and K-Ar ages: report 25

    International Nuclear Information System (INIS)

    Twenty-three 40Ar-39Ar age determinations (including two potassium-argon analyses) carried out by the Geological Survey of Canada are reported. Each age determination is accompanied by a description of the rock and mineral concentrate used; brief interpretative comments regarding the geological significance of each age are also provided where possible. The experimental procedures employed are described in outline. An index of all Geological Survey of Canada K-Ar age determinations published in this format has been prepared using NTS quadrangles as the primary reference. (author). 6 refs., 2 tabs., 1 fig

  9. Use of 4He-filled proportional counters as neutron spectrometers

    International Nuclear Information System (INIS)

    Neutron response functions of two commercially available cylindrical 4He-filled proportional counters (filling pressure about 2 MPa) have been measured in the neutron energy range 144-14000 keV. Measurements were carried out using optimal settings for the detector high voltage and amplifier shaping time which were determined within the scope of this study. The experimental results have been analyzed and compared to calculated response functions using empirically determined energy and resolution calibration functions. The theoretically determined response functions show good agreement with the measured response except for energies above 10 MeV. The discrepancies are attributed to unsatisfactory electronics. The Monte-Carlo code gas-filled neutron spectrometer response (GNSR) which has been developed for the calculation of response functions and efficiencies of gas-filled neutron detectors, is briefly described. (orig.)

  10. The ChArMEx database

    Science.gov (United States)

    Ferré, Hélène; Belmahfoud, Nizar; Boichard, Jean-Luc; Brissebrat, Guillaume; Cloché, Sophie; Descloitres, Jacques; Fleury, Laurence; Focsa, Loredana; Henriot, Nicolas; Mière, Arnaud; Ramage, Karim; Vermeulen, Anne; Boulanger, Damien

    2015-04-01

    The Chemistry-Aerosol Mediterranean Experiment (ChArMEx, http://charmex.lsce.ipsl.fr/) aims at a scientific assessment of the present and future state of the atmospheric environment in the Mediterranean Basin, and of its impacts on the regional climate, air quality, and marine biogeochemistry. The project includes long term monitoring of environmental parameters , intensive field campaigns, use of satellite data and modelling studies. Therefore ChARMEx scientists produce and need to access a wide diversity of data. In this context, the objective of the database task is to organize data management, distribution system and services, such as facilitating the exchange of information and stimulating the collaboration between researchers within the ChArMEx community, and beyond. The database relies on a strong collaboration between ICARE, IPSL and OMP data centers and has been set up in the framework of the Mediterranean Integrated Studies at Regional And Locals Scales (MISTRALS) program data portal. ChArMEx data, either produced or used by the project, are documented and accessible through the database website: http://mistrals.sedoo.fr/ChArMEx. The website offers the usual but user-friendly functionalities: data catalog, user registration procedure, search tool to select and access data... The metadata (data description) are standardized, and comply with international standards (ISO 19115-19139; INSPIRE European Directive; Global Change Master Directory Thesaurus). A Digital Object Identifier (DOI) assignement procedure allows to automatically register the datasets, in order to make them easier to access, cite, reuse and verify. At present, the ChArMEx database contains about 120 datasets, including more than 80 in situ datasets (2012, 2013 and 2014 summer campaigns, background monitoring station of Ersa...), 25 model output sets (dust model intercomparison, MEDCORDEX scenarios...), a high resolution emission inventory over the Mediterranean... Many in situ datasets

  11. Fabrication of ZnO photonic crystals by nanosphere lithography using inductively coupled-plasma reactive ion etching with CH4/H2/Ar plasma on the ZnO/GaN heterojunction light emitting diodes

    International Nuclear Information System (INIS)

    This article reports fabrication of n-ZnO photonic crystal/p-GaN light emitting diode (LED) by nanosphere lithography to further booster the light efficiency. In this article, the fabrication of ZnO photonic crystals is carried out by nanosphere lithography using inductively coupled plasma reactive ion etching with CH4/H2/Ar plasma on the n-ZnO/p-GaN heterojunction LEDs. The CH4/H2/Ar mixed gas gives high etching rate of n-ZnO film, which yields a better surface morphology and results less plasma-induced damages of the n-ZnO film. Optimal ZnO lattice parameters of 200 nm and air fill factor from 0.35 to 0.65 were obtained from fitting the spectrum of n-ZnO/p-GaN LED using a MATLAB code. In this article, we will show our recent result that a ZnO photonic crystal cylinder has been fabricated using polystyrene nanosphere mask with lattice parameter of 200 nm and radius of hole around 70 nm. Surface morphology of ZnO photonic crystal was examined by scanning electron microscope.

  12. Intense Infrared Scintillation of Liquid Ar-Xe Mixtures

    CERN Document Server

    Neumeier, A; Heindl, T; Himpsl, A; Hagn, H; Hofmann, M; Oberauer, L; Potzel, W; Roth, S; Schönert, S; Wieser, J; Ulrich, A

    2015-01-01

    Intense infrared (IR) light emission from liquid Ar-Xe mixtures has been observed using 12 keV electron-beam excitation. The emission peaks at a wavelength of 1.18 $\\mu$m and the half-width of the emission band is 0.1 $\\mu$m. Maximum intensity has been found for a 10 ppm xenon admixture in liquid argon. The conversion efficiency of electron beam-power to IR-light is about 1% (10000 photons per MeV electron energy deposited). A possible application of this intense IR emission for a new particle discrimination concept in liquid noble gas detectors is discussed. No light emission was found for perfectly purified liquid argon in the wavelength range from 0.5 to 3.5 $\\mu$m on the current level of sensitivity.

  13. Airborne contamination during blow-fill-seal pharmaceutical production.

    Science.gov (United States)

    Whyte, W; Matheis, W; Dean-Netcher, M; Edwards, A

    1998-01-01

    The routes of airborne contamination, during Blow-Fill-Seal (BFS) production, were studied using tracer gas, particles and bacteria. The prevention of airborne contamination, by the air shower at the point of fill, was effective (> 99.2% efficient). However, microbe-carrying particles could gain access, by deposition or air exchange, when the containers were cut open and before they shuttled under the protection of the air shower. The use of SF6 tracer gas demonstrated that when the air shower was not on, 50% of the air within the containers came from the area round the machine. When the air shower was switched on, only about 5% of the air came from the surroundings. Airborne microbial contamination of containers is in proportion to: the number of airborne microbes around the machine, the time the container is open, the neck area and the amount of air left within the container. The likely microbial contamination rate can be calculated from a model incorporating these variables. Microbial contamination of containers during BFS manufacturing is normally very low, but by increasing the naturally occurring bacteria in the air of the production rooms by about 100-fold, it was possible to verify the accuracy of this model. The contamination model agrees well with the observation that microbial contamination levels of between 1 in 10(5) and in 10(7) will be found when small containers (< 10 ml) are filled in conventionally ventilated rooms. To achieve similar contamination rates when filling of larger bottles, it is likely that unidirectional flow, or barrier technology will be required. PMID:9691671

  14. Cryogenic resonance-electron Moessbauer spectroscopy with a helium-filled proportional counter

    International Nuclear Information System (INIS)

    As studied in our previous works,a proportional counter filled with pure helium gas works well at low temperatures near 4.2 K. The helium-filled proportional counter (HFPC) provides us with method to detect nuclear radiations at low temperatures. A typical application of this counter is resonance-electron Moessbauer spectroscopy (REMS) at low temperatures (<∼30 K). In this article some examples of REMS measurements with HFPC are given. (author)

  15. Detonation and transition to detonation in partially water-filled pipes

    OpenAIRE

    Bitter, Neal P.; Shepherd, Joseph E.

    2012-01-01

    Detonations and deflagration-to-detonation transition (DDT) are experimentally studied in horizontal pipes which are partially filled with water. The gas layer above the water is stoichiometric hydrogen-oxygen at 1 bar. For detonation cases, ignition and transition occur outside of the water-filled section. For DDT cases, ignition and transition occur over the surface of the water. Pressure and hoop strain are measured incrementally along the pipe, with pressure transducers located both above...

  16. LHCB RICH gas system proposal

    CERN Document Server

    Bosteels, Michel; Haider, S

    2001-01-01

    Both LHCb RICH will be operated with fluorocarbon as gas radiator. RICH 1 will be filled with 4m^3 of C4F10 and RICH 2 with 100m^3 of CF4. The gas systems will run as a closed loop circulation and a gas recovery system within the closed loop is planned for RICH 1, where the recovery of the CF4 will only be realised during filling and emptying of the detector. Inline gas purification is foreseen for the gas systems in order to limit water and oxygen impurities.

  17. The ArDM, a ton-scale liquid argon experiment for direct dark matter detection

    International Nuclear Information System (INIS)

    Full text: The ArDM is a 1-ton liquid argon based experiment which aims at the direct detection of Weakly Interacting Massive Particles (WIMPs). The detector is sensitive to the small signals of scintillation light and the ionization charge independently. The sufficient discrimination between nuclear recoils and the background is possible by the ratio of scintillation to ionization and by the different time structure of the scintillation. In the present time the experiment is under construction at CERN. The detector was recently tested being fully filled with Liquid Argon. Promising results on the light yield and on the detector performance were obtained. (author)

  18. A comparative study of CF{sub 4}/O{sub 2}/Ar and C{sub 4}F{sub 8}/O{sub 2}/Ar plasmas for dry etching applications

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Inwoo [Department of Control and Instrumentation Engineering, Korea University, 2511 Sejong-Ro, Sejong 339-700 (Korea, Republic of); Efremov, Alexander [Department of Electronic Devices & Materials Technology, State University of Chemistry & Technology, 7F. Engels St., 153000 Ivanovo (Russian Federation); Yeom, Geun Young [Department of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kwon, Kwang-Ho, E-mail: kwonkh@korea.ac.kr [Department of Control and Instrumentation Engineering, Korea University, 2511 Sejong-Ro, Sejong 339-700 (Korea, Republic of)

    2015-03-31

    The effect of the O{sub 2}/Ar mixing ratio in CF{sub 4}/O{sub 2}/Ar and C{sub 4}F{sub 8}/O{sub 2}/Ar inductively coupled plasmas with a 50% fluorocarbon gas content on plasma parameters and active species densities, which influence dry etching mechanisms, was analyzed. The investigation combined plasma diagnostics using Langmuir probes and zero-dimensional plasma modeling. It was found that, in both gas systems, the substitution of Ar for O{sub 2} results in a similar change in the ion energy flux but causes the opposite behavior for the F atom flux. The mechanisms of these phenomena are discussed with regards to plasma chemistry. - Highlights: • The goal was to conduct a comparative study of CF{sub 4}/O{sub 2}/Ar and C{sub 4}F{sub 8}/O{sub 2}/Ar plasmas. • The focus was on the parameters directly influencing dry etching mechanisms. • Model-based analysis for neutral species was used in this paper.

  19. New Approach to Estimate 40Ar/36Ar Ratio in Shocked Meteorites

    Science.gov (United States)

    Fujimoto, H.; Hyodo, H.; Ninagawa, K.

    2008-12-01

    Measurement of a 40Ar/39Ar age in a meteorite requires proper estimation of a 40Ar/36Ar "initial" ratio. For a primordial one, it is reported to be an order of 10-4, suggesting that one can ignore it in age calculation. However, there is no basis for applying this value as individual meteorites have different histories. In terms of 40Ar/39Ar studies on various meteorites, very few studies discuss how the ratios were estimated. Using terrestrial value of 295.5 is invalid. The only case in which the ratio does not affect on the results is when an age of a meteorite is in an order of billion years, resulting in a large raw 40Ar/36Ar ratio. A proper approach to estimate the ratio is application of isochron analyses. When a small amount of sample (a few micrograms) is studied in laserprobe analysis, this often becomes difficult. A shocked meteorite Y-75097 has developed maskelynite veins, which were identified in optical microscope, electron microprobe and thermoluminescence studies. We have applied 40Ar/39Ar dating method using both stepwise heating by a continuous laser and pinpoint dating by a pulsed laser. Stepwise heating results of several fragments (about 50 micrograms) of the meteorite yielded various old and young ages. Most pinpoint analyses gave the raw 40Ar/36Ar ratio less than the terrestrial value with sporadically and anomalously old ages. Among the data, three points isochron from a maskelynite vein yielded about 300 Ma with "initial" ratio of 180. To confirm this result, plagioclase and olivine data near the vein were plotted in a correlation diagram, but an isochron is not well defined due to relatively large analytical errors. A new method to analyze these data is proposed. Once 40Ar/39Ar ratio is determined from an experiment, the only factor which determines the age is the "initial" ratio in the 40Ar/39Ar age equation. Instead of using a known fixed ratio, we set the ratio (y-axis) and the age (x-axis) as variables. In this diagram, a single data

  20. Inductively coupled plasma reactive ion etching of FePt magnetic thin films in a CH4/O2/Ar plasma

    International Nuclear Information System (INIS)

    An inductively coupled plasma (ICP) reactive ion etching of FePt thin films masked with TiN films was carried out in CH4/O2/Ar plasma. As CH4 gas was added to Ar, the etch rates of the FePt thin films and TiN hard mask decreased gradually, and the etch profile of the FePt films improved slightly. The addition of O2 gas to the CH4/Ar gas mixture enhanced the etch profile due to an increase in the etch selectivity of the FePt film to the TiN hard mask. From optical emission spectroscopy (OES) for the CH4/O2/Ar gas mix, the increase in etch selectivity was attributed to the increase in [H] species as well as [O] species due to the addition of O2 gas. With increasing ICP rf power and dc-bias voltage to the substrate, the etch rates increased and the etch profiles improved with a higher degree of anisotropy. X-ray photoelectron spectroscopy (XPS) of the etched FePt films revealed the existence of Fe-containing compounds formed during etching in CH4/O2/Ar plasma. The etch characteristics, OES and XPS analysis of the film surface showed that the etching of FePt films in CH4/O2/Ar plasma follows mainly sputter etching with the assistance of chemical reactions with the films. - Highlights: ► Development of a CH4/O2/Ar gas to etch FePt magnetic films ► Films etched by inductively coupled plasma reactive ion etching. ► Etch mechanism of FePt films in CH4/O2/Ar gas mixture ► High etch rate and high etch selectivity of FePt thin films ► Extremely high anisotropy of FePt films without redeposition or etch residue