WorldWideScience

Sample records for high vacuum evaporation-condensation

  1. Measure Guideline: Evaporative Condensers

    Energy Technology Data Exchange (ETDEWEB)

    German, A [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States); Dakin, B. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States); Hoeschele, M. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States)

    2012-03-01

    This measure guideline on evaporative condensers provides information on properly designing, installing, and maintaining evaporative condenser systems as well as understanding the benefits, costs, and tradeoffs. This is a prescriptive approach that outlines selection criteria, design and installation procedures, and operation and maintenance best practices.

  2. Measure Guideline: Evaporative Condensers

    Energy Technology Data Exchange (ETDEWEB)

    German, A.; Dakin, B.; Hoeschele, M.

    2012-03-01

    The purpose of this measure guideline on evaporative condensers is to provide information on a cost-effective solution for energy and demand savings in homes with cooling loads. This is a prescriptive approach that outlines selection criteria, design and installation procedures, and operation and maintenance best practices. This document has been prepared to provide a process for properly designing, installing, and maintaining evaporative condenser systems as well as understanding the benefits, costs, and tradeoffs.

  3. Test results of reliable and very high capillary multi-evaporators / condenser loop

    Energy Technology Data Exchange (ETDEWEB)

    Van Oost, S.; Dubois, M.; Bekaert, G. [Societe Anonyme Belge de Construction Aeronautique - SABCA (Belgium)

    1996-12-31

    The paper present the results of various SABCA activities in the field of two-phase heat transport system. These results have been based on a critical review and analysis of the existing two-phase loop and of the future loop needs in space applications. The research and the development of a high capillary wick (capillary pressure up to 38 000 Pa) are described. These activities have led towards the development of a reliable high performance capillary loop concept (HPCPL), which is discussed in details. Several loop configurations mono/multi-evaporators have been ground tested. The presented results of various tests clearly show the viability of this concept for future applications. Proposed flight demonstrations as well as potential applications conclude this paper. (authors) 7 refs.

  4. Quantitative microbiological analysis of bacterial community shifts in a high-rate anaerobic bioreactor treating sulfite evaporator condensate.

    Science.gov (United States)

    Ney, U; Macario, A J; Conway de Macario, E; Aivasidis, A; Schoberth, S M; Sahm, H

    1990-08-01

    The bacterial population of a high-rate, anaerobic, fixed-bed loop reactor treating sulfite evaporator condensate from the pulp industry was studied over a 14-month period. This period was divided into seven cycles that included a startup at the beginning of each cycle. Some 82% of the total biomass was immobilized on and between the porous glass rings filling the reactor. The range of the total number of microorganisms in these biofilms was 2 x 10 to 7 x 10 cells per ml. Enumeration and characterization by microbiological methods and by phase-contrast, epifluorescence, and electron microscopy showed that the samples consisted mainly of the following methanogens: a Methanobacterium sp., a Methanosarcina sp., a Methanobrevibacter sp., and a Methanothrix sp., as well as furfural-degrading sulfate-reducing bacteria resembling Desulfovibrio furfuralis. Viable counts of hydrogenotrophic methanogens were relatively stable (mostly within the range of 3.2 x 10 to 7.5 x 10 cells per ml), but Methanobrevibacter cells increased from fixed bed into a second reactor vessel. Acetotrophic methanogens reached their highest numbers of 1.3 x 10 to 2.6 x 10 cells per ml in the last fermentation cycles. They showed a morphological shift from sarcinalike packets in early samples to single coccoid forms in later phases of the fermentation. Furfural-degrading sulfate reducers reached counts of 1 x 10 to 5.8 x 10 cells per ml. The distribution of the chief metabolic groups between free fluid and biofilms was analyzed in the fifth fermentation cycle: 4.5 times more furfural degraders were found in the free fluid than in the biofilms. In contrast, 5.8 times more acetotrophic and 16.6 times more hydrogenotrophic methanogens were found in the biofilms than in the free liquid. The data concerning time shifts of morphotypes among the trophic groups of methanogens corroborated the trends observed by using immunological assays on the same samples.

  5. Evaporative Condensers in Comfortable Air Conditioning System

    Institute of Scientific and Technical Information of China (English)

    YIN Ying-de; ZHU Dong-sheng; DU Gui-mei; LI Yuan-xi; SUN He-jing; LIU Qing-ming

    2009-01-01

    The operating theory of an evaporative condenser was expatiated.The difference between an e-vaporative condensing refrigeration system and a general refrigeration system was analyzed.Compared with the air-cooled and the water-cooled,the virtues of energy-conservation and water-conservation of evaporative con-densers were analyzed.Some questions existing in the application of evaporative condensers were pointed out,the corresponding solving methods were analyzed accordingly,and the development trend of evaporative con-densing technique in mechanical refrigeration system field and the applied foreground of evaporative condensers in comfortable air conditioning were prospected.

  6. Analysis of an evaporator-condenser-separated mechanical vapor compression system

    Science.gov (United States)

    Wu, Hong; Li, Yulong; Chen, Jiang

    2013-04-01

    An evaporator-condenser-separated mechanical vapor compression (MVC) system was presented. The better effect of descaling and antiscaling was obtained by the new system. This study focused on the method of thermodynamic analysis, and the energy and exergy flow diagrams were established by using the first and second law of thermodynamics analysis. The results show that the energy utilization rate is very high and the specific power consumption is low. Exergy analysis indicates that the exergy efficiency is low, and the largest exergy loss occurs within the evaporator -condenser and the compressor.

  7. Improving Best Air Conditioner Efficiency by 20-30% through a High Efficiency Fan and Diffuser Stage Coupled with an Evaporative Condenser Pre-Cooler

    Energy Technology Data Exchange (ETDEWEB)

    Parker, Danny S; Sherwin, John R; Raustad, Richard

    2014-04-10

    The Florida Solar Energy Center (FSEC) conducted a research project to improve the best residential air conditioner condenser technology currently available on the market by retrofitting a commercially-available unit with both a high efficiency fan system and an evaporative pre-cooler. The objective was to integrate these two concepts to achieve an ultra-efficient residential air conditioner design. The project produced a working prototype that was 30% more efficient compared to the best currently-available technologies; the peak the energy efficiency ratio (EER) was improved by 41%. Efficiency at the Air-Conditioning and Refrigeration Institute (ARI) standard B-condition which is used to estimate seasonal energy efficiency ratio (SEER), was raised from a nominal 21 Btu/Wh to 32 Btu/Wh.

  8. Artificial neural network analysis of a refrigeration system with an evaporative condenser

    Energy Technology Data Exchange (ETDEWEB)

    Ertunc, H.M. [Department of Mechatronics Engineering, Kocaeli University, 41040 Kocaeli (Turkey); Hosoz, M. [Department of Mechanical Education, Kocaeli University, 41380 Kocaeli (Turkey)

    2006-04-01

    This paper describes an application of artificial neural networks (ANNs) to predict the performance of a refrigeration system with an evaporative condenser. In order to gather data for training and testing the proposed ANN, an experimental refrigeration system with an evaporative condenser was set up. Then, steady-state test runs were conducted varying the evaporator load, air and water flow rates passing through the condenser and both dry and wet bulb temperatures of the air stream entering the condenser. Utilizing some of the experimental data, an ANN model for the system based on standard backpropagation algorithm was developed. The ANN was used for predicting various performance parameters of the system, namely the condenser heat rejection rate, refrigerant mass flow rate, compressor power, electric power input to the compressor motor and the coefficient of performance. The ANN predictions usually agree well with the experimental values with correlation coefficients in the range of 0.933-1.000, mean relative errors in the range of 1.90-4.18% and very low root mean square errors. Results show that refrigeration systems, even complex ones involving concurrent heat and mass transfer such as systems with an evaporative condenser, can alternatively be modelled using ANNs within a high degree of accuracy. [Author].

  9. Beryllium coating produced by evaporation-condensation method and some their properties

    Energy Technology Data Exchange (ETDEWEB)

    Pepekin, G.I.; Anisimov, A.B.; Chernikov, A.S.; Mozherinn, S.I.; Pirogov, A.A. [SRI SIA Lutch., Podolsk (Russian Federation)

    1998-01-01

    The method of vacuum evaporation-condensation for deposition of beryllium coatings on metal substrates, considered in the paper, side by side with a plasma-spray method is attractive fon ITER application. In particular this technique may be useful for repair the surface of eroded tiles which is operated in a strong magnetic field. The possibility of deposition of beryllium coatings with the rate of layer growth 0.1-0.2 mm/h is shown. The compatibility of beryllium coating with copper or stainless steel substrate is provided due to intermediate barrier. The results of examination of microstructure, microhardness, porosity, thermal and physical properties and stability under thermal cycling of beryllium materials are presented. The value of thermal expansion coefficient and thermal conductivity of condensed beryllium are approximately the same as for industrial grade material produced by powder mettalurgy technique. However, the condensed beryllium has higher purity (up to 99.9-99.99 % wt.). (author)

  10. HIGH TEMPERATURE VACUUM MIXER

    Directory of Open Access Journals (Sweden)

    E. D. Chertov

    2015-01-01

    Full Text Available The work is devoted to the creation of a new type of mixer to produce homogeneous mixtures of dissimilar materials applied to recycling of housing and communal services waste. The article describes the design of a dual-chamber device of the original high-temperature vacuum mixer, there investigated the processes occurring in the chambers of such devices. The results of theoretical and experimental research of the process of mixing recycled polyethylene with a mixture of "grinded food waste – Eco wool” are presented. The problem of the optimum choice of bending the curvilinear blades in the working volume of the seal, which is achieved by setting their profile in the form of involute arc of several circles of different radii, is examined . The dependences, allowing to define the limits of the changes of the main mode parameters the angular velocity of rotation of the working body of the mixer using two ways of setting the profile of the curvilinear blade mixer are obtained. Represented design of the mixer is proposed to use for a wide range of tasks associated with the mixing of the components with a strongly pronounced difference of physic al chemical properties and, in particular, in the production of composites out of housing and communal services waste.

  11. Pore-scale evaporation-condensation dynamics resolved by synchrotron x-ray tomography

    Science.gov (United States)

    Shahraeeni, Ebrahim; Or, Dani

    2012-01-01

    Capillary processes greatly influence vapor mediated transport dynamics and associated changes in liquid phase content of porous media. Rapid x-ray synchrotron tomography measurements were used to resolve liquid-vapor interfacial dynamics during evaporation and condensation within submillimetric pores forming between sintered glass bead samples subjected to controlled ambient temperature and relative humidity. Evolution of gas-liquid interfacial shapes were in agreement with predictions based on our analytical model for interfacial dynamics in confined wedge-shaped pores. We also compared literature experimental data at the nanoscale to illustrate the capability of our model to describe early stages of condensation giving rise to the onset of capillary forces between rough surfaces. The study provides high resolution, synchrotron-based observations of capillary evaporation-condensation dynamics at the pore scale as the confirmation of the pore scale analytical model for capillary condensation in a pore and enables direct links with evolution of macroscopic vapor gradients within a sintered glass bead sample through their effect on configuration and evolution of the local interfaces. Rapid condensation processes play a critical role in the onset of capillary-induced friction affecting mechanical behavior of physical systems and industrial applications.

  12. High Vacuum Furnace for HIRFL-CSR

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In order to satisfy the requirement of ultra-high vacuum and low out-gassing rate of materials which are used to make HIIRFL-CSR vacuum chambers, a high vacuum furnace for degassing the beam chambers, flanges, and the other vacuum components has been designed and manufactured by IMP and Vacuum Equipment Factory in Lanzhou.

  13. Evaporation-condensation transition of the two-dimensional Potts model in the microcanonical ensemble

    KAUST Repository

    Nogawa, Tomoaki

    2011-12-05

    The evaporation-condensation transition of the Potts model on a square lattice is numerically investigated by the Wang-Landau sampling method. An intrinsically system-size-dependent discrete transition between supersaturation state and phase-separation state is observed in the microcanonical ensemble by changing constrained internal energy. We calculate the microcanonical temperature, as a derivative of microcanonical entropy, and condensation ratio, and perform a finite-size scaling of them to indicate the clear tendency of numerical data to converge to the infinite-size limit predicted by phenomenological theory for the isotherm lattice gas model. © 2011 American Physical Society.

  14. Evaporation-condensation transition of the two-dimensional Potts model in the microcanonical ensemble.

    Science.gov (United States)

    Nogawa, Tomoaki; Ito, Nobuyasu; Watanabe, Hiroshi

    2011-12-01

    The evaporation-condensation transition of the Potts model on a square lattice is numerically investigated by the Wang-Landau sampling method. An intrinsically system-size-dependent discrete transition between supersaturation state and phase-separation state is observed in the microcanonical ensemble by changing constrained internal energy. We calculate the microcanonical temperature, as a derivative of microcanonical entropy, and condensation ratio, and perform a finite-size scaling of them to indicate the clear tendency of numerical data to converge to the infinite-size limit predicted by phenomenological theory for the isotherm lattice gas model.

  15. Effects of Evaporation/Condensation on Spreading and Contact Angle of a Volatile Liquid Drop

    Science.gov (United States)

    Zhang, Nengli; Chao, David F.; Singh, Bhim S. (Technical Monitor)

    2000-01-01

    Effects of evaporation/condensation on spreading and contact angle were experimentally studied. A sessile drop of R-113 was tested at different vapor environments to determine the effects of evaporation/condensation on the evolution of contact diameter and contact angle of the drop. Condensation on the drop surface occurs at both the saturated and a nonsaturated vapor environments and promotes the spreading. When the drop is placed in the saturated vapor environment it tends to completely wetting and spreads rapidly. In a nonsaturated vapor environment, the evolution of the sessile drop is divided three stages: condensation-spreading stage, evaporation-retracting stage and rapid contracting stage. In the first stage the drop behaves as in the saturated environment. In the evaporation -retracting stage, the competition between spreading and evaporation of the drop determines the evolution characteristics of the contact diameter and the contact angle. A lower evaporation rate struggles against the spreading power to turn the drop from spreading to retracting with a continuous increase of the contact angle. The drop placed in open air has a much higher evaporation rate. The strong evaporation suppresses the spreading and accelerates the retraction of the drop with a linear decrease of the contact diameter. The contraction of the evaporating drops is gradually accelerated when the contact diameter decreases to 3 min and less till drying up, though the evaporation rate is gradually slowing down.

  16. Comparative analysis of an evaporative condenser using artificial neural network and adaptive neuro-fuzzy inference system

    Energy Technology Data Exchange (ETDEWEB)

    Metin Ertunc, H. [Department of Mechatronics Engineering, Kocaeli University, Umuttepe, 41380 Kocaeli (Turkey); Hosoz, Murat [Department of Mechanical Education, Kocaeli University, Umuttepe, 41380 Kocaeli (Turkey)

    2008-12-15

    This study deals with predicting the performance of an evaporative condenser using both artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) techniques. For this aim, an experimental evaporative condenser consisting of a copper tube condensing coil along with air and water circuit elements was developed and equipped with instruments used for temperature, pressure and flow rate measurements. After the condenser was connected to an R134a vapour-compression refrigeration circuit, it was operated at steady state conditions, while varying both dry and wet bulb temperatures of the air stream entering the condenser, air and water flow rates as well as pressure, temperature and flow rate of the entering refrigerant. Using some of the experimental data for training, ANN and ANFIS models for the evaporative condenser were developed. These models were used for predicting the condenser heat rejection rate, refrigerant temperature leaving the condenser along with dry and wet bulb temperatures of the leaving air stream. Although it was observed that both ANN and ANFIS models yielded a good statistical prediction performance in terms of correlation coefficient, mean relative error, root mean square error and absolute fraction of variance, the accuracies of ANFIS predictions were usually slightly better than those of ANN predictions. This study reveals that, having an extended prediction capability compared to ANN, the ANFIS technique can also be used for predicting the performance of evaporative condensers. (author)

  17. Silicates materials of high vacuum technology

    CERN Document Server

    Espe, Werner

    2013-01-01

    Materials of High Vacuum Technology, Volume 2: Silicates covers silicate insulators of special importance to vacuum technology. The book discusses the manufacture, composition, and physical and chemical properties of technical glasses, quartz glass, quartzware, vycor glass, ceramic materials, mica, and asbestos.

  18. STRUCTURE IMPROVEMENT AND TEMPERATURE FIELD SIMULATION OF PREPARING NANOPOWDER BY EVAPORATION-CONDENSATION METHOD

    Institute of Scientific and Technical Information of China (English)

    J.S.Bao; Y.Yin; T.G.Liu; Z.Y.Yang

    2008-01-01

    A new apparatus, with a segregable conical water cooling condenser, which is heated by an electric arc using the evaporation-condensation method to prepare carbon-coated nanopowder, has been developed by the authors. Numerical simulation of the temperaturc field is done by the ANSYS software, and temperature in the reaction vessel is measured with the help of an experiment, to verify the simulation result. Influence of the temperature field in the reaction vessel, on the process of preparing nanopowder is then discussed simply. It is shown that the segrcgable conical water cooling condenser and carbon-coated surface process can be used to prepare steady carbon-coated metal nanopowder, at a lower cost and higher yield rate than the traditional structure. Simulation of the temperature field in the apparatus shows that the arc heating method can form a temperature field in the apparatus, which is quite favorable for nanopowder formation. Experiments show that the rational parameters using this apparatus, with the arc heating method to prepare carbon-coated nanopowder are electricity 60-100 A and arc length 5-8 mm.

  19. Pressurization of a Flightweight, Liquid Hydrogen Tank: Evaporation & Condensation at a Liquid/Vapor Interface

    Science.gov (United States)

    Stewart, Mark E. M.

    2017-01-01

    This paper presents an analysis and simulation of evaporation and condensation at a motionless liquid/vapor interface. A 1-D model equation, emphasizing heat and mass transfer at the interface, is solved in two ways, and incorporated into a subgrid interface model within a CFD simulation. Simulation predictions are compared with experimental data from the CPST Engineering Design Unit tank, a cryogenic fluid management test tank in 1-g. The numerical challenge here is the physics of the liquid/vapor interface; pressurizing the ullage heats it by several degrees, and sets up an interfacial temperature gradient that transfers heat to the liquid phase-the rate limiting step of condensation is heat conducted through the liquid and vapor. This physics occurs in thin thermal layers O(1 mm) on either side of the interface which is resolved by the subgrid interface model. An accommodation coefficient of 1.0 is used in the simulations which is consistent with theory and measurements. This model is predictive of evaporation/condensation rates, that is, there is no parameter tuning.

  20. Can hydrodynamic contact line paradox be solved by evaporation-condensation?

    Science.gov (United States)

    Janeček, V; Doumenc, F; Guerrier, B; Nikolayev, V S

    2015-12-15

    We investigate a possibility to regularize the hydrodynamic contact line singularity in the configuration of partial wetting (liquid wedge on a solid substrate) via evaporation-condensation, when an inert gas is present in the atmosphere above the liquid. The no-slip condition is imposed at the solid-liquid interface and the system is assumed to be isothermal. The mass exchange dynamics is controlled by vapor diffusion in the inert gas and interfacial kinetic resistance. The coupling between the liquid meniscus curvature and mass exchange is provided by the Kelvin effect. The atmosphere is saturated and the substrate moves at a steady velocity with respect to the liquid wedge. A multi-scale analysis is performed. The liquid dynamics description in the phase-change-controlled microregion and visco-capillary intermediate region is based on the lubrication equations. The vapor diffusion is considered in the gas phase. It is shown that from the mathematical point of view, the phase exchange relieves the contact line singularity. The liquid mass is conserved: evaporation existing on a part of the meniscus and condensation occurring over another part compensate exactly each other. However, numerical estimations carried out for three common fluids (ethanol, water and glycerol) at the ambient conditions show that the characteristic length scales are tiny.

  1. Can hydrodynamic contact line paradox be solved by evaporation--condensation?

    CERN Document Server

    Janeček, V; Guerrier, B; Nikolayev, V S

    2016-01-01

    We investigate a possibility to regularize the hydrodynamic contact line singularity in the configuration of partial wetting (liquid wedge on a solid substrate) via evaporation-condensation, when an inert gas is present in the atmosphere above the liquid. The no-slip condition is imposed at the solid-liquid interface and the system is assumed to be isothermal. The mass exchange dynamics is controlled by vapor diffusion in the inert gas and interfacial kinetic resistance. The coupling between the liquid meniscus curvature and mass exchange is provided by the Kelvin effect. The atmosphere is saturated and the substrate moves at a steady velocity with respect to the liquid wedge. A multi-scale analysis is performed. The liquid dynamics description in the phase-change-controlled microregion and visco-capillary intermediate region is based on the lubrication equations. The vapor diffusion is considered in the gas phase. It is shown that from the mathematical point of view, the phase exchange relieves the contact l...

  2. Evaporation condensation-induced bubble motion after temperature gradient set-up

    Science.gov (United States)

    Nikolayev, Vadim S.; Garrabos, Yves; Lecoutre, Carole; Pichavant, Guillaume; Chatain, Denis; Beysens, Daniel

    2017-01-01

    Thermocapillary (Marangoni) motion of a gas bubble (or a liquid drop) under a temperature gradient can hardly be present in a one-component fluid. Indeed, in such a pure system, the vapor-liquid interface is always isothermal (at saturation temperature). However, evaporation on the hot side and condensation on the cold side can occur and displace the bubble. We have observed such a phenomenon in two different fluids submitted to a temperature gradient under reduced gravity: hydrogen under magnetic compensation of gravity in the HYLDE facility at CEA-Grenoble and water in the DECLIC facility onboard the ISS. The experiments and the subsequent analysis are performed in the vicinity of the vapor-liquid critical point to benefit from critical universality. In order to better understand the phenomena, a 1D numerical simulation has been performed. After the temperature gradient is imposed, two regimes can be evidenced. At early times, the temperatures in the bubble and the surrounding liquid become different thanks to their different compressibility and the "piston effect" mechanism, i.e. the fast adiabatic bulk thermalization induced by the expansion of the thermal boundary layers. The difference in local temperature gradients at the vapor-liquid interface results in an unbalanced evaporation/condensation phenomenon that makes the shape of the bubble vary and provoke its motion. At long times, a steady temperature gradient progressively forms in the liquid (but not in the bubble) and induces steady bubble motion towards the hot end. We evaluate the bubble velocity and compare with existing theories.

  3. Materials for high vacuum technology, an overview

    CERN Document Server

    Sgobba, Stefano

    2007-01-01

    In modern accelerators stringent requirements are placed on materials of vacuum systems. Their physical and mechanical properties, machinability, weldability or brazeability are key parameters. Adequate strength, ductility, magnetic properties at room as well as low temperatures are important factors for vacuum systems of accelerators working at cryogenic temperatures, such as the Large Hadron Collider (LHC) under construction at CERN. In addition, baking or activation of Non-Evaporable Getters (NEG) at high temperatures impose specific choices of material grades of suitable tensile and creep properties in a large temperature range. Today, stainless steels are the dominant materials of vacuum constructions. Their metallurgy is extensively treated. The reasons for specific requirements in terms of metallurgical processes are detailed, in view of obtaining adequate purity, inclusion cleanliness, and fineness of the microstructure. In many cases these requirements are crucial to guarantee the final leak tightnes...

  4. THE FRICTION OF QUARTZ IN HIGH VACUUM

    Science.gov (United States)

    the effects of surface cleanliness . Ultra-high vacuums (to 10 to the minus 10th power torr) and high temperatures (to 350 deg C) were combined with...chemical cleaning and careful handling techniques to produce the maximum surface cleanliness . The coefficient of static friction under varying...on 30-40 mesh glass balls. The coefficient of friction of smooth quartz was found to vary from 0.1 to 1.0 depending on the surface cleanliness . The

  5. Vacuum MOCVD fabrication of high efficience cells

    Science.gov (United States)

    Partain, L. D.; Fraas, L. M.; Mcleod, P. S.; Cape, J. A.

    1985-01-01

    Vacuum metal-organic-chemical-vapor-deposition (MOCVD) is a new fabrication process with improved safety and easier scalability due to its metal rather than glass construction and its uniform multiport gas injection system. It uses source materials more efficiently than other methods because the vacuum molecular flow conditions allow the high sticking coefficient reactants to reach the substrates as undeflected molecular beams and the hot chamber walls cause the low sticking coefficient reactants to bounce off the walls and interact with the substrates many times. This high source utilization reduces the materials costs power device and substantially decreases the amounts of toxic materials that must be handled as process effluents. The molecular beams allow precise growth control. With improved source purifications, vacuum MOCVD has provided p GaAs layers with 10-micron minority carrier diffusion lengths and GaAs and GaAsSb solar cells with 20% AMO efficiencies at 59X and 99X sunlight concentration ratios. Mechanical stacking has been identified as the quickest, most direct and logical path to stacked multiple-junction solar cells that perform better than the best single-junction devices. The mechanical stack is configured for immediate use in solar arrays and allows interconnections that improve the system end-of-life performance in space.

  6. Procurement specification high vacuum test chamber and pumping system

    Energy Technology Data Exchange (ETDEWEB)

    Cormick, J. E.

    1976-05-31

    The specification establishes requirements for a high-vacuum test chamber, associated vacuum pumps, valves, controls, and instrumentation that shall be designed and fabricated for use as a test chamber for testing a closed loop Brayton Isotope Power System (BIPS) Ground Demonstration System (GDS). The vacuum system shall include all instrumentation required for pressure measurement and control of the vacuum pumping system. A general outline of the BIPS-GDS in the vacuum chamber and the preliminary piping and instrumentation interface to the vacuum chamber are shown.

  7. High vacuum tribology of polycrystalline diamond coatings

    Indian Academy of Sciences (India)

    Awadesh K Mallik; S A Shivashankar; S K Biswas

    2009-10-01

    Polycrystalline diamond coatings have been grown on unpolished side of Si(100) wafers by hot filament chemical vapour deposition process. The morphology of the grown coatings has been varied from cauliflower morphology to faceted morphology by manipulation of the growth temperature from 700°C to 900°C and methane gas concentration from 3% to 1·5%. It is found that the coefficient of friction of the coatings under high vacuum of 133·32 × 10-7 Pa (10-7 torr) with nanocrystalline grains can be manipulated to 0·35 to enhance tribological behaviour of bare Si substrates.

  8. High Vacuum Techniques for Anionic Polymerization

    KAUST Repository

    Ratkanthwar, Kedar

    2015-09-01

    Anionic polymerization high vacuum techniques (HVTs) are the most suitable for the preparation of polymer samples with well-defined complex macromolecular architectures. Though HVTs require glassblowing skill for designing and making polymerization reactor, it is the best way to avoid any termination of living polymers during the number of steps for the synthesis of polymers with complex structure. In this chapter, we describe the different polymerization reactors and HVTs for the purification of monomers, solvents, and other reagents for anionic polymerization as well as few model reactions for the synthesis of polymers with simple to complex structure.

  9. Application of plate evaporative condenser on a 300 MW direct air-cooling unit%板式蒸发式凝汽器在300 MW直接空冷机组中的应用

    Institute of Scientific and Technical Information of China (English)

    吕凯; 彭兆春; 刘文华; 李高潮; 叶军; 陈胜利

    2015-01-01

    针对直接空冷机组在夏季时背压偏高、出力受限的问题,提出采用板式蒸发式凝汽器分流部分汽轮机排汽,以降低空冷岛热负荷,从而降低机组背压.以某300 MW直接空冷机组为例进行上述技术改造.改造后机组运行结果表明:额定负荷工况、环境温度30℃下,投运板式蒸发式凝汽器系统后,机组背压由33.47 kPa 降至29.05 kPa,达到了额定工况下,对机组背压的要求(设计值30 kPa);TRL工况、环境温度30℃下(湿球温度为17.68℃),板式蒸发式凝汽器系统冷凝能力为50.11 t/h,机组背压较投运前降低4.1 kPa;板式蒸发式凝汽器的水耗率为0.7~0.8;板式蒸发式凝汽器系统的运行效果随着环境温度的升高而提高;板式蒸发式凝汽器的冷凝量和补水流量随着外部空气湿度的增大而减小,且趋势相同,空气湿度增大到一定程度后,其冷凝量和补水流量趋于定值.%In summer,the direct air cooling units will suffer high back pressure and its output power will be insufficient.Against this problem,the plate evaporative condensing system was proposed to diverge part of the turbine exhaust steam and reduce the heat load of air cooling island,thus the unit operating back pres-sure can be decreased.Taking a 300 MW direct air cooling unit as the example,the retrofitting was carried out.The operation results show that,under condition with rated load and ambient temperature of 30 ℃,af-ter the plate evaporative condensing system was put into service,the unit back pressure decreased from 33. 47 kPa to 29.05 kPa,satisfying the requirements under rated condition (30 kPa).Under the TRL condition and at ambient temperature of 30 ℃ (the wet bulb temperature of 17.68 ℃),the condensing ability of the plate evaporative condensing system was 50.11 t/h,and the unit back pressure decreased by 4.1 kPa.The water consumption rate of the plate evaporative condensing system was 0.7 to 0.8.The

  10. Design and development of low pressure evaporator/condenser unit for water-based adsorption type climate control systems

    Science.gov (United States)

    Venkataramanan, Arjun; Rios Perez, Carlos A.; Hidrovo, Carlos H.

    2016-11-01

    Electric vehicles (EVs) are the future of clean transportation and driving range is one of the important parameters which dictates its marketability. In order to increase driving range, electrical battery energy consumption should be minimized. Vapor-compression refrigeration systems currently employed in EVs for climate control consume a significant fraction of the battery charge. Thus, by replacing this traditional heating ventilation and air-conditioning system with an adsorption based climate control system one can have the capability of increasing the drive range of EVs.The Advanced Thermo-adsorptive Battery (ATB) for climate control is a water-based adsorption type refrigeration cycle. An essential component of the ATB is a low pressure evaporator/condenser unit (ECU) which facilitates both the evaporation and condensation processes. The thermal design of the ECU relies predominantly on the accurate prediction of evaporation/boiling heat transfer coefficients since the standard correlations for predicting boiling heat transfer coefficients have large uncertainty at the low operating pressures of the ATB. This work describes the design and development of a low pressure ECU as well as the thermal performance of the actual ECU prototype.

  11. CSRm Ultra-High Vacuum System

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The new accelerator project ( HIRFL-CSR ) constructed at the Heavy Ion Research Facility in Lanzhou (HIRFL) is approaching completion. It is a multipurpose cooler-storage-ring system [1], consisting of a maim ring (CSRm), an experimental ring (CSRe) and two transfer beam lines. The UHV system of CSRm is the most representative subsystem in the project. To minimize the beam loss due to charge exchange of the heavy ions with the residual gas molecules,the pressure of the CSRm vacuum system should reach 3.5 × 10-9 Pa (N2 equivalent) and the pressure of 8 × 10-10 Pa is expected for very heavy ion such as uranium to make its lifetime longer than 50 s in the ring. Now, the vacuum system of CSRm has been completed and a pressure less than 5 × 10-10 Pa has been obtained. In this paper the layout of the CSRm vacuum system, the vacuum equipment in CSRm, the treatment method for the CSRm vacuum chambers, and the installation and operation of the system will be reported.

  12. New Materials for Vacuum Chambers in High Energy Physics

    CERN Document Server

    Garion, Cédric

    2014-01-01

    Vacuum chambers must fulfil ultra-high vacuum requirements while withstanding thermo-mechanical loads. This is particularly true in high energy particle accelerator where interactions of particles with matter may induce thermal load, material activation, background… The choice of the material of the vacuum chamber is crucial for the final application. Metals such as stainless steel, copper and aluminium are usually used. Even with outstanding mechanical and physical properties, beryllium is used for very specific applications because of its cost and toxicity.Ceramics such as alumina are usually used for fast magnet vacuum chambers. With the next generation of high energy physics accelerator generation such as CLIC and TLEP, the problematic of high cyclic thermal load induced by synchrotron radiation is raised. This paper aims at defining some figures of merit of different materials with respect to several load scenarios and presents briefly their vacuum compatibility.

  13. MEMS ion-sorption high vacuum pump

    Science.gov (United States)

    Grzebyk, T.; Knapkiewicz, P.; Szyszka, P.; Gorecka-Drzazga, A.; Dziuban, J. A.

    2016-11-01

    In the article a miniature MEMS-type ion-sorption vacuum pump has been presented. The influence of electric and magnetic field, as well as horizontal and vertical dimensions of the micropump and type of material used for electrodes on the pump properties has been investigated. It has been found that the micropump works efficiently as long as the magnetic field is higher than 0.3 T, and pumping cell is larger than 1x1x1 mm3. The pump allows generating vacuum at the level of 10-7-10-9 hPa in 100 mm3 volume.

  14. Vacuum amplification of the high-frequency electromagnetic radiation

    OpenAIRE

    Vilkovisky, G. A.

    1998-01-01

    When an electrically charged source is capable of both emitting the electromagnetic waves and creating charged particles from the vacuum, its radiation gets so much amplified that only the backreaction of the vacuum makes it finite. The released energy and charge are calculated in the high-frequency approximation. The technique of expectation values is advanced and employed.

  15. Evaporative Condenser and Heat Transfer Enhancement%蒸发式冷凝器传热强化研究及应用现状分析

    Institute of Scientific and Technical Information of China (English)

    李若兰; 彭鹏

    2015-01-01

    介绍蒸发式冷凝器工程信息:结构形式,强化传热技术,强化传热效率;应用现状;运行面临的问题及应对方法;简述蒸发式冷凝器的工作原理,分析强化传热机理。%This article introduces the engineering information of the evaporative condenser:the structural form , the enhanced heat transfer technology , the enhanced heat transfer efficiency , the application status , the operation problems and response measures. Briefly describe the working principle of the evaporative condenser, and analyzes its enhanced heat transfer mechanism.

  16. Modeling and simulation of evaporative condensation cooling water system for subway%地铁蒸发冷凝冷水系统建模与仿真

    Institute of Scientific and Technical Information of China (English)

    孙超

    2016-01-01

    针对某地铁车站的空调水系统,描述系统中各主要组件的数学模型,在 EASY5平台上建立空调水系统仿真模型,将冷却塔系统与蒸发冷凝系统进行对比。结果表明:蒸发冷凝系统的COP 明显高于风冷系统,且系统动态响应更快,建立的仿真模型能够为蒸发冷凝冷水系统的模拟提供参考。%The mathematical model of the main components is described according to the air-conditioning water system for subway.The simulation model of air-conditioning water system is established based on EASY5 .The evaporative condensation system is compared with the cooling tower system.The results show that the COP of the evapora-tive condensation cooling water system is higher than that of the air cooling system and its dynamic response is faster.The simulation model can provide valuable reference for the simulation of evaporative condensation cooling water system.

  17. Design of intelligent controller for evaporative condenser%蒸发式冷凝器智能控制器设计

    Institute of Scientific and Technical Information of China (English)

    姜珊; 冯恩民; 于洪海

    2012-01-01

    An intelligent controller for evaporative condenser is introduced, including both hardware and software. One or more evaporative condensers can be controlled by this intelligent controller with intelligence,modularity and net-working operation in the project, and it's easy to operate and manage. This intelligent controller reduces the initial investment cost and running cost of evaporative condensers to be energy-saving and has broad market prospects.%从硬件和软件两方面介绍一种用于蒸发式冷凝器自动控制的智能控制器.该智能控制器能够实现工程上单台或多台蒸发式冷凝器运行控制的智能化、模块化和网络化,便于运行管理,同时降低制冷系统的初投资及运行成本,节能降耗,具有广泛的市场前景.

  18. Evaporation-condensation synthesis and optical property of In2O3 octahedrons

    Science.gov (United States)

    Senapati, Subrata; Nanda, Karuna Kar

    2015-06-01

    Synthesis of In2O3 octahedrons is carried out successfully by heating Indium metal pieces in air ambient. The sample is characterized by scanning electron microscopy (SEM), Energy dispersive X-ray spectroscope (EDS), X-ray diffraction (XRD) and Raman spectroscopy. The as-prepared In2O3 octahedrons are highly crystalline and exhibit body centered cubic structure. Room temperature and temperature (293-453K) dependence photoluminescence reveals a deep levelbroad emission of yellowish-orange spectra centered around 605 nm. The emission is due to the presence of defect levels in the band gap of materials.

  19. Optical levitation of high purity nanodiamonds in vacuum without heating

    CERN Document Server

    Frangeskou, A C; Gines, L; Mandal, S; Williams, O A; Barker, P F; Morley, G W

    2016-01-01

    Levitated nanodiamonds containing nitrogen vacancy centres in high vacuum are a potential test bed for numerous phenomena in fundamental physics. However, experiments so far have been limited to low vacuum due to heating arising from optical absorption of the trapping laser. We show that milling pure diamond creates nanodiamonds that do not heat up as the optical intensity is raised above 700 GW/m$^2$ below 5 mbar of pressure. This advance now means that the level of attainable vacuum for nanodiamonds in optical dipole traps is no longer temperature limited.

  20. Ultra-high vacuum in superconducting accelerator rings

    Science.gov (United States)

    Bazanov, A. M.; Butenko, A. V.; Galimov, A. R.; Lugovnin, A. K.; Smirnov, A. V.

    2016-12-01

    Achieving the ultra-high vacuum (UHV) in the collider and booster of the NICA project is one of the main challenges when creating this device. It determines the need for a serious approach to this issue and conducting research in this direction. First, it is necessary to understand the effect of the various components of the vacuum systems on the degree of vacuum. It is also necessary to carry out studies of pumping devices for producing the required vacuum (10-9 Pa) in the beam chamber and choose the most optimal pumping scheme. At the same time, it is necessary to figure out how various operations are carried out with the vacuum chamber: preparation of vacuum surfaces, letting in the atmosphere, and warming the chamber after closing the influence on the degree of vacuum and the composition of the residual gas. The temperature may vary from room temperature to liquid helium temperature due to the difficulty of keeping the beam-chamber walls at a constant temperature, including the inner components. This complicates the processes taking place within it. Additional complexity arises due the heating of the chamber walls by various processes during the operation of the accelerator (for example, cycling the magnetic field).

  1. Vacuum high harmonic generation in the shock regime

    CERN Document Server

    Böhl, P; Ruhl, H

    2015-01-01

    Electrodynamics becomes nonlinear and permits the self-interaction of fields when the quantised nature of vacuum states is taken into account. The effect on a plane probe pulse propagating through a stronger constant crossed background is calculated using numerical simulation and by analytically solving the corresponding wave equation. The electromagnetic shock resulting from vacuum high harmonic generation is investigated and a nonlinear shock parameter identified.

  2. Measuring vacuum polarization with high-power lasers

    Institute of Scientific and Technical Information of China (English)

    B.King; T.Heinzl

    2016-01-01

    When exposed to intense electromagnetic fields, the quantum vacuum is expected to exhibit properties of a polarizable medium akin to a weakly nonlinear dielectric material. Various schemes have been proposed to measure such vacuum polarization effects using a combination of high- power lasers. Motivated by several planned experiments, we provide an overview of experimental signatures that have been suggested to confirm this prediction of quantum electrodynamics of real photon–photon scattering.

  3. Overview of High Power Vacuum Dry RF Load Designs

    Energy Technology Data Exchange (ETDEWEB)

    Krasnykh, Anatoly [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-27

    A specific feature of RF linacs based on the pulsed traveling wave (TW) mode of operation is that only a portion of the RF energy is used for the beam acceleration. The residual RF energy has to be terminated into an RF load. Higher accelerating gradients require higher RF sources and RF loads, which can stably terminate the residual RF power. RF feeders (from the RF source though the accelerating section to the load) are vacuumed to transmit multi-megawatt high power RF. This overview will outline vacuumed RF loads only. A common method to terminate multi-MW RF power is to use circulated water (or other liquid) as an absorbing medium. A solid dielectric interface (a high quality ceramic) is required to separate vacuum and liquid RF absorber mediums. Using such RF load approaches in TW linacs is troubling because there is a fragile ceramic window barrier and a failure could become catastrophic for linac vacuum and RF systems. Traditional loads comprising of a ceramic disk have limited peak and average power handling capability and are therefore not suitable for high gradient TW linacs. This overview will focus on ''vacuum dry'' or ''all-metal'' loads that do not employ any dielectric interface between vacuum and absorber. The first prototype is an original design of RF loads for the Stanford Two-Mile Accelerator.

  4. Superconducting Vacuum-Gap Crossovers for High Performance Microwave Applications

    CERN Document Server

    Denis, Kevin L; Chang, Meng-Ping; Hu, Ron; U-Yen, Kongpop; Wollack, Edward

    2016-01-01

    The design and fabrication of low-loss wide-bandwidth superconducting vacuum-gap crossovers for high performance millimeter wave applications are described. In order to reduce ohmic and parasitic losses at millimeter wavelengths a vacuum gap is preferred relative to dielectric spacer. Here, vacuum-gap crossovers were realized by using a sacrificial polymer layer followed by niobium sputter deposition optimized for coating coverage over an underlying niobium signal layer. Both coplanar waveguide and microstrip crossover topologies have been explored in detail. The resulting fabrication process is compatible with a bulk micro-machining process for realizing waveguide coupled detectors, which includes sacrificial wax bonding, and wafer backside deep reactive ion etching for creation of leg isolated silicon membrane structures. Release of the vacuum gap structures along with the wax bonded wafer after DRIE is implemented in the same process step used to complete the detector fabrication

  5. A transparent vacuum window for high-intensity pulsed beams

    CERN Document Server

    Monteil, M; Veness, R

    2011-01-01

    The HiRadMat (High-Radiation to Materials) facility Ill will allow testing of accelerator components, in particular those of the Large Hadron Collider (LHC) at CERN, under the impact of high-intensity pulsed beams. To reach this intensity range, the beam will be focused on a focal point where the target to be tested is located. A 60 mm aperture vacuum window will separate the vacuum of the beam line which is kept under high vacuum 10(-8) mbar, from the test area which is at atmospheric pressure. This window has to resist collapse due to beam passage. The high-intensity of the beam means that typical materials used for standard vacuum windows (such as stainless steel, aluminium and titanium alloy) cannot endure the energy deposition induced by the beam passage. Therefore, a vacuum window has been designed to maintain the differential pressure whilst resisting collapse due to the beam impact on the window. In this paper, we will present calculations of the energy transfer from beam to window, the design of the ...

  6. Long distance manipulation of a levitated nanoparticle in high vacuum

    CERN Document Server

    Mestres, Pau; Spasenović, Marko; Gieseler, Jan; Novotny, Lukas; Quidant, Romain

    2015-01-01

    Accurate delivery of small targets in high vacuum is a pivotal task in many branches of science and technology. Beyond the different strategies developed for atoms, proteins, macroscopic clusters and pellets, the manipulation of neutral particles over macroscopic distances still poses a formidable challenge. Here we report a novel approach based on a mobile optical trap operated under feedback control that enables long range 3D manipulation of a silica nanoparticle in high vacuum. We apply this technique to load a single nanoparticle into a high-finesse optical cavity through a load-lock vacuum system. We foresee our scheme to benefit the field of optomechanics with levitating nano-objects as well as ultrasensitive detection and monitoring.

  7. A squeezed light source operated under high vacuum

    Science.gov (United States)

    Wade, Andrew R.; Mansell, Georgia L.; Chua, Sheon S. Y.; Ward, Robert L.; Slagmolen, Bram J. J.; Shaddock, Daniel A.; McClelland, David E.

    2015-01-01

    Non-classical squeezed states of light are becoming increasingly important to a range of metrology and other quantum optics applications in cryptography, quantum computation and biophysics. Applications such as improving the sensitivity of advanced gravitational wave detectors and the development of space-based metrology and quantum networks will require robust deployable vacuum-compatible sources. To date non-linear photonics devices operated under high vacuum have been simple single pass systems, testing harmonic generation and the production of classically correlated photon pairs for space-based applications. Here we demonstrate the production under high-vacuum conditions of non-classical squeezed light with an observed 8.6 dB of quantum noise reduction down to 10 Hz. Demonstration of a resonant non-linear optical device, for the generation of squeezed light under vacuum, paves the way to fully exploit the advantages of in-vacuum operations, adapting this technology for deployment into new extreme environments. PMID:26657616

  8. Plasma backflow phenomenon in high-current vacuum arc

    Energy Technology Data Exchange (ETDEWEB)

    Wang Lijun [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); Jia Shenli [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); Zhang Ling [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); Shi Zongqian [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); Yang Dingge [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); Gentils, Francois [Schneider Electric SAS, 37 quai Paul-Louis Merlin, 38050 Grenoble Cedex 9 (France); Jusselin, BenoIt [Schneider Electric SAS, 37 quai Paul-Louis Merlin, 38050 Grenoble Cedex 9 (France)

    2007-10-07

    Based on the two-temperature magnetohydrodynamic model, a high-current vacuum arc (HCVA) in vacuum interrupters is simulated and analysed. The phenomenon of plasma backflow in arc column is found, which is ultimately ascribed to the strong magnetic pinch effect of HCVA. Due to plasma backflow, the maximal value of ion density at the cathode side is not located at the centre of the cathode side, but at the paraxial region of the cathode side, that is to say, ion density appears to sag at the centre of the cathode side (arc column seems to be divided into two parts). The sag of light intensity is also found by experiments.

  9. Vacuum stripping of ethanol during high solids fermentation of corn.

    Science.gov (United States)

    Shihadeh, Jameel K; Huang, Haibo; Rausch, Kent D; Tumbleson, Mike E; Singh, Vijay

    2014-05-01

    In corn-ethanol industry, yeast stress inducing glucose concentrations produced during liquefaction and subsequent high ethanol concentrations produced during fermentation restrict slurry solids to 32 % w/w. These limits were circumvented by combining two novel technologies: (1) granular starch hydrolyzing enzyme (GSHE) to break down starch simultaneously with fermentation and (2) vacuum stripping to remove ethanol. A vacuum stripping system was constructed and applied to fermentations at 30, 40, and 45 % solids. As solids increased from 30 to 40 %, ethanol yield decreased from 0.35 to 0.29 L/kg. Ethanol yield from 45 % solids was only 0.18 L/kg. An improvement was conducted by increasing enzyme dose from 0.25 to 0.75 g/g corn and reducing yeast inoculum by half. After improvement, ethanol yield from 40 % solids vacuum treatment increased to 0.36 L/kg, comparable to ethanol yield from 30 % solids (control).

  10. A highly reliable trigger for vacuum ARC plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Bernardet, H.; Godechot, X.; Jarjat, F. [SODERN, Limeil-Brevannes (France)

    1996-08-01

    The authors have developed a reliable electrical trigger and its associated circuitry to fire vacuum arc plasma or ion source. They tested different embodiments of the trigger device in order to get a highly reliable one, which is able to perform more than 1.2 x 10{sup 6} shots at 60 A and 6.5 ps pulse length. The evolution of the ion current emitted has been recorded as a function of the number of shots. They have also investigated in which direction the plasma jet is emitted : axially or radially. This device can be used to fire a vacuum arc plasma or ion source by plasma injection. It has obvious advantage to be placed outside the cathode and therefore would ease maintenance of vacuum arc devices.

  11. Vacuum high-harmonic generation and electromagnetic shock

    Science.gov (United States)

    Böhl, P.; King, B.; Ruhl, H.

    2016-04-01

    > When one takes into account the presence of virtual charged states in the quantum vacuum, a nonlinear self-interaction can arise in the propagation of electromagnetic fields. This self-interaction is often referred to as `real photon-photon scattering'. When the centre-of-mass energy of colliding photons is much lower than the rest energy of an electron-positron pair, this quantum effect can be included in the classical field equations of motion as a vacuum current and charge density using the Heisenberg-Euler Lagrangian. Using analytical and numerical methods for subcritical fields, the intrinsic solution to Maxwell's equations has been found for counterpropagating probe and pump plane waves in the presence of vacuum four- and six-wave mixing. In the corresponding all-order solution for the scattered probe, a route to vacuum high-harmonic generation is identified in which a long phase length can compensate for the weakness of interacting fields. The resulting shocks in the probe carrier wave and envelope are studied for different parameter regimes and polarisation set-ups. In this special issue, we study two additional set-ups: that of a slowly varying single-cycle background to highlight the effect of an oscillating background on the probe harmonic spectrum, and that of a few-cycle probe to highlight the smoothing of the harmonic peaks produced by a wider spectrum of probe photons. We also correct sign errors in an earlier publication.

  12. An Underappreciated Radiation Hazard from High Voltage Electrodes in Vacuum

    CERN Document Server

    West, Adam; DeMille, David; West, Elizabeth; Panda, Cristian; Doyle, John; Gabrielse, Gerald; Kryskow, Adam; Mitchell, Corinne

    2016-01-01

    The use of high voltage (HV) electrodes in vacuum is commonplace in physics laboratories. In such systems, it has long been known that electron emission from an HV cathode can lead to bremsstrahlung X-rays; indeed, this is the basic principle behind the operation of standard X-ray sources. However, in laboratory setups where X-ray production is not the goal and no electron source is deliberately introduced, field-emitted electrons accelerated by HV can produce X-rays as an unintended hazardous byproduct. Both the level of hazard and the safe operating regimes for HV vacuum electrode systems are not widely appreciated, at least in university laboratories. A reinforced awareness of the radiation hazards associated with vacuum HV setups would be beneficial. We present a case study of a HV vacuum electrode device operated in a university atomic physics laboratory. We describe the characterisation of the observed X-ray radiation, its relation to the observed leakage current in the device, the steps taken to contai...

  13. An Underappreciated Radiation Hazard from High Voltage Electrodes in Vacuum.

    Science.gov (United States)

    West, Adam D; Lasner, Zack; DeMille, David; West, Elizabeth P; Panda, Cristian D; Doyle, John M; Gabrielse, Gerald; Kryskow, Adam; Mitchell, Corinne

    2017-01-01

    The use of high voltage (HV) electrodes in vacuum is commonplace in physics laboratories. In such systems, it has long been known that electron emission from an HV cathode can lead to bremsstrahlung x rays; indeed, this is the basic principle behind the operation of standard x-ray sources. However, in laboratory setups where x-ray production is not the goal and no electron source is deliberately introduced, field-emitted electrons accelerated by HV can produce x rays as an unintended hazardous byproduct. Both the level of hazard and the safe operating regimes for HV vacuum electrode systems are not widely appreciated, at least in university laboratories. A reinforced awareness of the radiation hazards associated with vacuum HV setups would be beneficial. The authors present a case study of a HV vacuum electrode device operated in a university atomic physics laboratory. They describe the characterization of the observed x-ray radiation, its relation to the observed leakage current in the device, the steps taken to contain and mitigate the radiation hazard, and suggested safety guidelines.

  14. Understanding and Improving High Voltage Vacuum Insulators for Microsecond Pulses

    Energy Technology Data Exchange (ETDEWEB)

    Javedani, J B; Goerz, D A; Houck, T L; Lauer, E J; Speer, R D; Tully, L K; Vogtlin, G E; White, A D

    2007-03-05

    High voltage insulation is one of the main areas of pulsed power research and development, and dielectric breakdown is usually the limiting factor in attaining the highest possible performance in pulsed power devices. For many applications the delivery of pulsed power into a vacuum region is the most critical aspect of operation. The surface of an insulator exposed to vacuum can fail electrically at an applied field more than an order or magnitude below the bulk dielectric strength of the insulator. This mode of breakdown, called surface flashover, imposes serious limitations on the power flow into a vacuum region. This is especially troublesome for applications where high voltage conditioning of the insulator and electrodes is not practical and for applications where relatively long pulses, on the order of several microseconds, are required. The goal of this project is to establish a sound fundamental understanding of the mechanisms that lead to surface flashover, and then evaluate the most promising techniques to improve vacuum insulators and enable high voltage operation at stress levels near the intrinsic bulk breakdown limits of the material. The approach we proposed and followed was to develop this understanding through a combination of theoretical and computation methods coupled with experiments to validate and quantify expected behaviors. In this report we summarize our modeling and simulation efforts, theoretical studies, and experimental investigations. The computational work began by exploring the limits of commercially available codes and demonstrating methods to examine field enhancements and defect mechanisms at microscopic levels. Plasma simulations with particle codes used in conjunction with circuit models of the experimental apparatus enabled comparisons with experimental measurements. The large scale plasma (LSP) particle-in-cell (PIC) code was run on multiprocessor platforms and used to simulate expanding plasma conditions in vacuum gap regions

  15. Vacuum Window Design for High-Power Lasers

    CERN Document Server

    Shaftan, T V

    2005-01-01

    One of the problems in the high-power lasers design is in outcoupling of a powerful laser beam out of a vacuum volume into atmosphere. Usually the laser device is located inside a vacuum tank. The laser radiation is transported to the outside world through the transparent vacuum window. While considered transparent, some of the light passing through the glass is absorbed and converted to heat. For most applications, these properties are academic curiosities; however, in multi-kilowatt lasers, the heat becomes significant and can lead to a failure. The absorbed power can result in thermal stress, reduction of light transmission and, consequently, window damage. Modern optical technology has developed different types of glass (Silica, BK7, diamond, etc.) that have high thermal conductivity and damage threshold. However, for kilo- and megawatt lasers the issue still remains open. In this paper we present a solution that may relieve the heat load on the output window. We discuss advantages and issues of this part...

  16. Experimental study on the storage performance of high-vacuum-multilayer-insulation tank after sudden, catastrophic loss of insulating vacuum

    Science.gov (United States)

    Xie, G. F.; Li, X. D.; Wang, R. S.

    2012-05-01

    High-vacuum-multilayer-insulation (HVMLI) cryogenic tank is one kind of dangerous pressure vessels. One of the worst accidents that may occur in a high-vacuum-multilayer-insulation (HVMLI) cryogenic tank is a sudden, catastrophic loss of insulating vacuum (SCLIV). The influence of SCLIV on storage performance for a HVMLI cryogenic tank is experimentally studied in this paper. A test rig was built up and experiments were conducted using LN2 as the test medium. The cryogenic tank was tested in the conditions of various combinations with different initial liquid level and number of insulation layers. Some important conclusions for storage performance with a vacuum-lost HVMLI cryogenic tank have been obtained. The experimental results show that the numbers of insulation layers and the initial liquid level have obvious effect on the storage performance after SCLIV for cryogenic tanks.

  17. Low-Cost, Rugged High-Vacuum System

    Science.gov (United States)

    Sorensen, Paul; Kline-Schoder, Robert

    2012-01-01

    A need exists for miniaturized, rugged, low-cost high-vacuum systems. Recent advances in sensor technology have led to the development of very small mass spectrometer detectors as well as other analytical instruments such as scanning electron microscopes. However, the vacuum systems to support these sensors remain large, heavy, and power-hungry. To meet this need, a miniaturized vacuum system was developed based on a very small, rugged, and inexpensive-to-manufacture molecular drag pump (MDP). The MDP is enabled by a miniature, very-high-speed (200,000 rpm), rugged, low-power, brushless DC motor optimized for wide temperature operation and long life. The key advantages of the pump are reduced cost and improved ruggedness compared to other mechanical hig-hvacuum pumps. The machining of the rotor and stators is very simple compared to that necessary to fabricate rotor and stator blades for other pump designs. Also, the symmetry of the rotor is such that dynamic balancing of the rotor will likely not be necessary. Finally, the number of parts in the unit is cut by nearly a factor of three over competing designs. The new pump forms the heart of a complete vacuum system optimized to support analytical instruments in terrestrial applications and on spacecraft and planetary landers. The MDP achieves high vacuum coupled to a ruggedized diaphragm rough pump. Instead of the relatively complicated rotor and stator blades used in turbomolecular pumps, the rotor in the MDP consists of a simple, smooth cylinder of aluminum. This will turn at approximately 200,000 rpm inside an outer stator housing. The pump stator comprises a cylindrical aluminum housing with one or more specially designed grooves that serve as flow channels. To minimize the length of the pump, the gas is forced down the flow channels of the outer stator to the base of the pump. The gas is then turned and pulled toward the top through a second set of channels cut into an inner stator housing that surrounds the

  18. High-temperature vacuum distillation separation of plutonium waste salts

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, E. [Los Alamos National Lab., NM (United States)

    1996-10-01

    In this task, high-temperature vacuum distillation separation is being developed for residue sodium chloride-potassium chloride salts resulting from past pyrochemical processing of plutonium. This process has the potential of providing clean separation of the salt and the actinides with minimal amounts of secondary waste generation. The process could produce chloride salt that could be discarded as low-level waste (LLW) or low actinide content transuranic (TRU) waste, and a concentrated actinide oxide powder that would meet long-term storage standards (DOE-DTD-3013-94) until a final disposition option for all surplus plutonium is chosen.

  19. Hydrogen permeability of Nb membrane annealed under ultra high vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, Helmut T.; Pundt, Astrid; Kirchheim, Reiner [Institut fuer Materialphysik, Goettingen (Germany); Yamazaki, Yoshihiro [California Institute of Technology, California (United States); Kamegawa, Atsunori; Takamura, Hitoshi; Koike, Junichi; Okada, Masuo [Department of Materials Science, School of Engineering, Tohoku University, Sendai (Japan)

    2007-07-01

    In this research, hydrogen permeability of Pd-free Nb membrane using hydrogen annealing process by ultra high vacuum equipment was investigated. Pure Nb (99.85 percent) was used as membrane. The hydrogen permeation experiment was carried out in the temperature range of 773-1173 K, and the H{sub 2} pressure range of 1-3.5 atm in the inlet side. Hydrogen flux and hydrogen pressures in the inlet side and outlet side of chamber were measured using mass flow meter and capacitance manometer, respectively. Hydrogen permeability was determined by Fick's first low. Effects of annealing conditions and heat treatment under hydrogen atmosphere on hydrogen permeability were investigated. It is supposed that the surface oxidation of Nb is reduced by the hydrogen annealing. Moreover, it is found that the value of hydrogen permeability becomes almost equivalent to the theoretical value when the sample preparation was optimized by an extension of the evacuating time. The best hydrogen permeability is obtained in metal membranes using the annealing under ultra-high vacuum and pure hydrogen atmosphere.

  20. New perspectives in vacuum high voltage insulation. II. Gas desorption

    CERN Document Server

    Diamond, W T

    1998-01-01

    An examination has been made of gas desorption from unbaked electrodes of copper, niobium, aluminum, and titanium subjected to high voltage in vacuum. It has been shown that the gas is composed of water vapor, carbon monoxide, and carbon dioxide, the usual components of vacuum outgassing, plus an increased yield of hydrogen and light hydrocarbons. The gas desorption was driven by anode conditioning as the voltage was increased between the electrodes. The gas is often desorbed as microdischarges-pulses of a few to hundreds of microseconds-and less frequently in a more continuous manner without the obvious pulsed structure characteristic of microdischarge activity. The quantity of gas released was equivalent to many monolayers and consisted mostly of neutral molecules with an ionic component of a few percent. A very significant observation was that the gas desorption was more dependent on the total voltage between the electrodes than on the electric field. It was not triggered by field-emitted electrons but oft...

  1. Cavity Control and Cooling of Nanoparticles in High Vacuum

    Science.gov (United States)

    Millen, James

    2016-05-01

    Levitated systems are a fascinating addition to the world of optically-controlled mechanical resonators. It is predicted that nanoparticles can be cooled to their c.o.m. ground state via the interaction with an optical cavity. By freeing the oscillator from clamping forces dissipation and decoherence is greatly reduced, leading to the potential to produce long-lived, macroscopically spread, mechanical quantum states, allowing tests of collapse models and any mass limit of quantum physics. Reaching the low pressures required to cavity-cool to the ground state has proved challenging. Our approach is to cavity cool a beam of nanoparticles in high vacuum. We can cool the c.o.m. motion of nanospheres, and control the rotation of nanorods, with the potential to produce cold, aligned nanostructures. Looking forward, we will utilize novel microcavities to enhance optomechanical cooling, preparing particles in a coherent beam ideally suited to ultra-high mass interferometry at 107 a.m.u.

  2. Advances in high voltage insulation and arc interruption in SF6 and vacuum

    CERN Document Server

    Maller, V N

    1982-01-01

    Advances in High Voltage Insulation and Arc Interruption in SF6 and Vacuum deals with high voltage breakdown and arc extinction in sulfur hexafluoride (SF6) and high vacuum, with special emphasis on the application of these insulating media in high voltage power apparatus and devices. The design and developmental aspects of various high voltage power apparatus using SF6 and high vacuum are highlighted. This book is comprised of eight chapters and opens with a discussion on electrical discharges in SF6 and high vacuum, along with the properties and handling of SF6 gas. The following chapters fo

  3. High-Reflectivity Coatings for a Vacuum Ultraviolet Spectropolarimeter

    Science.gov (United States)

    Narukage, Noriyuki; Kubo, Masahito; Ishikawa, Ryohko; Ishikawa, Shin-nosuke; Katsukawa, Yukio; Kobiki, Toshihiko; Giono, Gabriel; Kano, Ryouhei; Bando, Takamasa; Tsuneta, Saku; Auchère, Frédéric; Kobayashi, Ken; Winebarger, Amy; McCandless, Jim; Chen, Jianrong; Choi, Joanne

    2017-03-01

    Precise polarization measurements in the vacuum ultraviolet (VUV) region are expected to be a new tool for inferring the magnetic fields in the upper atmosphere of the Sun. High-reflectivity coatings are key elements to achieving high-throughput optics for precise polarization measurements. We fabricated three types of high-reflectivity coatings for a solar spectropolarimeter in the hydrogen Lyman-α (Lyα; 121.567 nm) region and evaluated their performance. The first high-reflectivity mirror coating offers a reflectivity of more than 80 % in Lyα optics. The second is a reflective narrow-band filter coating that has a peak reflectivity of 57 % in Lyα, whereas its reflectivity in the visible light range is lower than 1/10 of the peak reflectivity (˜ 5 % on average). This coating can be used to easily realize a visible light rejection system, which is indispensable for a solar telescope, while maintaining high throughput in the Lyα line. The third is a high-efficiency reflective polarizing coating that almost exclusively reflects an s-polarized beam at its Brewster angle of 68° with a reflectivity of 55 %. This coating achieves both high polarizing power and high throughput. These coatings contributed to the high-throughput solar VUV spectropolarimeter called the Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP), which was launched on 3 September, 2015.

  4. High Specific Surface area Aerogel Cryoadsorber for Vacuum Pumping Applications

    Energy Technology Data Exchange (ETDEWEB)

    Hill, Randal M.; Fought, Eric R.; Biltoft, Peter J.

    1998-12-22

    A cryogenic pumping system is provided, comprising a vacuum environment, an aerogel sorbent formed from a carbon aerogel disposed within the vacuum environment, and cooling means for cooling the aerogel sorbent sufficiently to adsorb molecules from the vacuum environment onto the aerogel sorbent. Embodiments of the invention include a liquid refrigerant cryosorption pump, a compressed helium cryogenic pump, a cryopanel and a Meissner coil, each of which uses carbon aerogel as a sorbent material.

  5. Ferroelectric Domain Imaging Mechanism in High-Vacuum Scanning Force Microscopy

    Institute of Scientific and Technical Information of China (English)

    ZENG Hua-Rong; YU Han-Feng; CHU Rui-Qing; LI Guo-Rong; YIN Qing-Rui

    2005-01-01

    @@ High-vacuum scanning force microscopy of the domain structures in PMN-PT single crystals is investigated. It has been shown that under high vacuum conditions, the polarization charges are not effectively compensated for by intrinsic screening charges from the ferroelectrics. This result suggests that the electrostatic tip-sample interaction plays a great contribution to the domain imaging mechanism in PMN-PT ferroelectric single crystals under high vacuum conditions.

  6. Ultra-high vacuum compatible preparation chain for intermetallic compounds

    Science.gov (United States)

    Bauer, A.; Benka, G.; Regnat, A.; Franz, C.; Pfleiderer, C.

    2016-11-01

    We report the development of a versatile material preparation chain for intermetallic compounds, which focuses on the realization of a high-purity growth environment. The preparation chain comprises an argon glovebox, an inductively heated horizontal cold boat furnace, an arc melting furnace, an inductively heated rod casting furnace, an optically heated floating-zone furnace, a resistively heated annealing furnace, and an inductively heated annealing furnace. The cold boat furnace and the arc melting furnace may be loaded from the glovebox by means of a load-lock permitting to synthesize compounds starting with air-sensitive elements while handling the constituents exclusively in an inert gas atmosphere. All furnaces are all-metal sealed, bakeable, and may be pumped to ultra-high vacuum. We find that the latter represents an important prerequisite for handling compounds with high vapor pressure under high-purity argon atmosphere. We illustrate the operational aspects of the preparation chain in terms of the single-crystal growth of the heavy-fermion compound CeNi2Ge2.

  7. Evaporation-condensation synthesis and optical property of In{sub 2}O{sub 3} octahedrons

    Energy Technology Data Exchange (ETDEWEB)

    Senapati, Subrata, E-mail: subrata@mrc.iisc.ernet.in; Nanda, Karuna Kar [Materials Research Centre, Indian Institute of Science, Bangalore-560012, Karnataka (India)

    2015-06-24

    Synthesis of In{sub 2}O{sub 3} octahedrons is carried out successfully by heating Indium metal pieces in air ambient. The sample is characterized by scanning electron microscopy (SEM), Energy dispersive X-ray spectroscope (EDS), X-ray diffraction (XRD) and Raman spectroscopy. The as-prepared In{sub 2}O{sub 3} octahedrons are highly crystalline and exhibit body centered cubic structure. Room temperature and temperature (293-453K) dependence photoluminescence reveals a deep levelbroad emission of yellowish-orange spectra centered around 605 nm. The emission is due to the presence of defect levels in the band gap of materials.

  8. Avoiding vacuum arcs in high gradient normal conducting RF structures

    CERN Document Server

    Sjøbæk, Kyrre Ness; Adli, Erik; Grudiev, Alexej; Wuensch, Walter

    In order to build the Compact LInear Collider (CLIC), accelerating structures reaching extremely high accelerating gradients are needed. Such structures have been built and tested using normal-conducting copper, powered by X-band RF power and reaching gradients of 100 MV/m and above. One phenomenon that must be avoided in order to reliably reach such gradients, is vacuum arcs or “breakdowns”. This can be accomplished by carefully designing the structure geometry such that high surface fields and large local power flows are avoided. The research presented in this thesis presents a method for optimizing the geometry of accelerating structures so that these breakdowns are made less likely, allowing the structure to operate reliably at high gradients. This was done primarily based on a phenomenological scaling model, which predicted the maximum gradient as a function of the break down rate, pulse length, and field distribution in the structure. The model is written in such a way that it allows direct comparis...

  9. Copper coated carbon fiber reinforced plastics for high and ultra high vacuum applications

    Science.gov (United States)

    Burri, F.; Fertl, M.; Feusi, P.; Henneck, R.; Kirch, K.; Lauss, B.; Rüttimann, P.; Schmidt-Wellenburg, P.; Schnabel, A.; Voigt, J.; Zenner, J.; Zsigmond, G.

    2014-03-01

    We have used copper-coated carbon fiber reinforced plastic (CuCFRP) for the construction of high and ultra-high vacuum recipients. The vacuum performance is found to be comparable to typical stainless steel used for this purpose. In test recipients we have reached pressures of 2E-8 mbar and measured a desorption rate of 1E-11 mbar*liter/s/cm^2; no degradation over time (2 years) has been found. Suitability for baking has been found to depend on the CFRP production process, presumably on the temperature of the autoclave curing. Together with other unique properties of CuCFRP such as low weight and being nearly non-magnetic, this makes it an ideal material for many high-end vacuum applications.

  10. Copper coated carbon fiber reinforced plastics for high and ultra high vacuum applications

    CERN Document Server

    Burri, F; Feusi, P; Henneck, R; Kirch, K; Lauss, B; Ruettimann, P; Schmidt-Wellenburg, P; Schnabel, A; Voigt, J; Zenner, J; Zsigmond, G

    2013-01-01

    We have used copper-coated carbon fiber reinforced plastic (CuCFRP) for the construction of high and ultra-high vacuum recipients. The vacuum performance is found to be comparable to typical stainless steel used for this purpose. In test recipients we have reached pressures of 2E-8 mbar and measured a desorption rate of 1E-11 mbar*liter/s/cm^2; no degradation over time (2 years) has been found. Suitability for baking has been found to depend on the CFRP production process, presumably on the temperature of the autoclave curing. Together with other unique properties of CuCFRP such as low weight and being nearly non-magnetic, this makes it an ideal material for many high-end vacuum applications.

  11. Cavity cooling of free silicon nanoparticles in high vacuum.

    Science.gov (United States)

    Asenbaum, Peter; Kuhn, Stefan; Nimmrichter, Stefan; Sezer, Ugur; Arndt, Markus

    2013-01-01

    Laser cooling has given a boost to atomic physics throughout the last 30 years, as it allows one to prepare atoms in motional states, which can only be described by quantum mechanics. Most methods rely, however, on a near-resonant and cyclic coupling between laser light and well-defined internal states, which has remained a challenge for mesoscopic particles. An external cavity may compensate for the lack of internal cycling transitions in dielectric objects and it may provide assistance in the cooling of their centre-of-mass state. Here we demonstrate cavity cooling of the transverse kinetic energy of silicon nanoparticles freely propagating in high vacuum (<10(-8) mbar). We create and launch them with longitudinal velocities down to v≤1 m s(-1) using laser-induced ablation of a pristine silicon wafer. Their interaction with the light of a high-finesse infrared cavity reduces their transverse kinetic energy by up to a factor of 30.

  12. Highly efficient vacuum processed BHJ solar cell based on merocyanines

    Energy Technology Data Exchange (ETDEWEB)

    Steinmann, Vera; Kronenberg, Nils M.; Lenze, Martin R.; Hertel, Dirk; Meerholz, Klaus [Department fuer Chemie, Universitaet Koeln (Germany); Buerckstuemmer, Hannah; Wuerthner, Frank [Institut fuer Organische Chemie, Roentgen Research Center for Complex Material Systems, Universitaet Wuerzburg (Germany)

    2011-07-01

    Bulk heterojunction (BHJ) organic solar cells have attracted considerable interest due to their potential for large-scale, cost-effective and environmentally friendly power generation. Small molecules have been successfully introduced in solution- (SOL) as well as vacuum- (VAC) processed devices, reporting efficiencies (PCE) up to 4.4% and 5.7% respectively. For simple layer stack devices (2-3 layers) based on CuPc as electron donor and C{sub 60} as electron acceptor PCEs up to 5.0% have been achieved. Recently, we presented a direct comparison of highly efficient SOL and VAC BHJ cells based on merocyanine dyes (MC) with a similarly simple layer stack as reported in the literature. Our most efficient devices exhibited PCEs up to 4.9%. Further optimizations on the VAC processed cells led to high PCEs exceeding 6% while keeping the same simple layer stack. In addition, these cells have demonstrated exceptional performance even at lower light intensities. Due to the simple chemical variability of MC dyes, they are ideally suited for tandem solar cells. We present first attempts in this direction.

  13. High pressure hydrocracking of vacuum gas oil to middle distillates

    Science.gov (United States)

    Lahiri, C. R.; Biswas, Dipa

    1986-05-01

    Hydrocracking of heavier petroleum fractions into lighter ones is of increasing importance today to meet the huge demand, particularly for gasoline and middle distillates. Much work on hydrocracking of a gas oil range feed stock to mainly gasoline using modified zeolite catalyst-base exchanged with metals (namely Ni, Pd, Mo, etc.) has been reported. In India, however, present demand is for a maximum amount of middle distillate. The present investigation was therefore aimed to maximize the yield of middle distillate (140-270°C boiling range) by hydrocracking a vacuum gas oil (365-450°C boiling range) fraction from an Indian Refinery at high hydrogen pressure and temperature. A zeolite catalyst-base exchanged with 4.5% Ni was chosen for the reaction. A high pressure batch reactor with a rocking arrangement was used for the study. No pretreatment of the feed stock for sulphur removal applied as the total sulphur in the feed was less than 2%. The process variables studied for the maximum yield of the middle distillate were temperature 300-450°C, pressure 100-200 bar and residence period 1-3 h at the feed to catalyst ratio of 9.3 (wt/wt). The optimum conditions for the maximum yield of 36% middle distillate of the product were: temperature 400°C, pressure 34.5 bar (initially) and residence period 2 h. A carbon balance of 90-92% was found for each run.

  14. High Voltage Coaxial Vacuum Gap Breakdown for Pulsed Power Liners

    Science.gov (United States)

    Cordaro, Samuel; Bott-Suzuki, Simon; Caballero Bendixsen, Luis Sebastian

    2015-11-01

    The dynamics of Magnetized Liner Inertial Fusion (MagLIF)1, are presently under detailed study at Sandia National Laboratories. Alongside this, a comprehensive analysis of the influence of the specific liner design geometry in the MagLIF system on liner initiation is underway in the academic community. Recent work at UC San Diego utilizes a high voltage pulsed system (25kV, 150ns) to analyze the vacuum breakdown stage of liner implosion. Such experimental analyses are geared towards determining how the azimuthal symmetry of coaxial gap breakdown affect plasma initiation within the liner. The final aim of the experimental analysis is to assess to what scale symmetry remains important at high (MV) voltages. An analysis of the above will utilize plasma self-emission via optical MCP, current measurements, voltage measurements near the gap, exact location of breakdown via 2D b-dot probe triangulation, as well as measuring the evolution of the B-field along the length of the liner via b-dot array. Results will be discussed along with analytical calculations of breakdown mechanisms

  15. Research for Surface Insulating Treatment Technique in High Vacuum

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Many insulation components are installed in the main vacuum chamber (5×10-6 Pa) of the 100 MeV compact cyclotron under development. The material of these components should be of low outgas rate,

  16. Highly precise and compact ultrahigh vacuum rotary feedthrough

    Science.gov (United States)

    Aiura, Y.; Kitano, K.

    2012-03-01

    The precision and rigidity of compact ultrahigh vacuum (UHV) rotary feedthroughs were substantially improved by preparing and installing an optimal crossed roller bearing with mounting holes. Since there are mounting holes on both the outer and inner races, the bearing can be mounted directly to rotary and stationary stages without any fixing plates and housing. As a result, it is possible to increase the thickness of the bearing or the size of the rolling elements in the bearing without increasing the distance between the rotating and fixing International Conflat flanges of the UHV rotary feedthrough. Larger rolling elements enhance the rigidity of the UHV rotary feedthrough. Moreover, owing to the structure having integrated inner and outer races and mounting holes, the performance is almost entirely unaffected by the installation of the bearing, allowing for a precise optical encoder to be installed in the compact UHV rotary feedthrough. Using position feedback via a worm gear system driven by a stepper motor and a precise rotary encoder, the actual angle of the compact UHV rotary feedthrough can be controlled with extremely high precision.

  17. The system for delivery of IR laser radiaton into high vacuum

    CERN Document Server

    Abakumova, E V; Krasnov, A A; Muchnoi, N Yu; Pyata, E E

    2015-01-01

    The system for insertion of a laser beam into the vacuum chamber of high-energy storage ring is described. The main part of the system is the high-vacuum viewport for the IR radiation, based on ZnSe or GaAs crystals. The design of the viewports is presented.

  18. Calculation Method to Determine the Group Composition of Vacuum Distillate with High Content of Saturated Hydrocarbons

    Directory of Open Access Journals (Sweden)

    Nazarova Galina

    2016-01-01

    Full Text Available Calculation method to determine the group composition of the heavy fraction of vacuum distillate with high content of saturated hydrocarbons, obtained by vacuum distillation of the residue from the West Siberian oil with subsequent hydrotreating, are given in this research. The method is built on the basis of calculation the physico-chemical characteristics and the group composition of vacuum distillate according to the fractional composition and density considering with high content of saturated hydrocarbons in the fraction. Calculation method allows to determine the content of paraffinic, naphthenic, aromatic hydrocarbons and the resins in vacuum distillate with high accuracy and can be used in refineries for rapid determination of the group composition of vacuum distillate.

  19. High current multicharged metal ion source using high power gyrotron heating of vacuum arc plasma.

    Science.gov (United States)

    Vodopyanov, A V; Golubev, S V; Khizhnyak, V I; Mansfeld, D A; Nikolaev, A G; Oks, E M; Savkin, K P; Vizir, A V; Yushkov, G Yu

    2008-02-01

    A high current, multi charged, metal ion source using electron heating of vacuum arc plasma by high power gyrotron radiation has been developed. The plasma is confined in a simple mirror trap with peak magnetic field in the plug up to 2.5 T, mirror ratio of 3-5, and length variable from 15 to 20 cm. Plasma formed by a cathodic vacuum arc is injected into the trap either (i) axially using a compact vacuum arc plasma gun located on axis outside the mirror trap region or (ii) radially using four plasma guns surrounding the trap at midplane. Microwave heating of the mirror-confined, vacuum arc plasma is accomplished by gyrotron microwave radiation of frequency 75 GHz, power up to 200 kW, and pulse duration up to 150 micros, leading to additional stripping of metal ions by electron impact. Pulsed beams of platinum ions with charge state up to 10+, a mean charge state over 6+, and total (all charge states) beam current of a few hundred milliamperes have been formed.

  20. Efficient thermoelectric trap for metal vapours suitable for high-vacuum system

    Science.gov (United States)

    Piwinski, Mariusz; Klosowski, Lukasz; Dziczek, Darek; Chwirot, Stanislaw

    2016-09-01

    Atomic beams are widely used in various collisional experiments. Typically, cold traps are used to prevent the investigated atoms from spreading within the vacuum chamber and contaminating the system. Usually such a trap consists of a vacuum feedthrough with metal element cooled with liquid nitrogen or dry ice on the atmosphere side and a metal trap in the vacuum. Using liquid nitrogen or dry ice is relatively inconvenient due to high costs of operation and a need of periodically refilling the reservoir of the cold medium. We present a new thermoelectric cold trap composed of water-cooled vacuum feedthrough with Peltier modules placed at the high vacuum end. The present system ensures the cold trap temperature below -20°C, low enough to efficiently catch the atoms of interest. The new cold trap was characterised and compared with typical LN2 trap.

  1. Flexible Furnace Concepts for Vacuum Heat Treatment Combined with High-pressure Gas Quenching

    Institute of Scientific and Technical Information of China (English)

    Karl Ritter; Stefan Wiebach

    2004-01-01

    IN the past five years the process combination of vacuum hardening, respectively vacuum carburizing with high-pressure gas quenching was successfully introduced to the market, especially in the manufacture of gears. In the meantime furnace concepts for various applications are available to the industry. In the following report three plant varieties are introduced, which differ in process flexibility and throughput. This report also explains criteria for the selection of a furnace in view of the existing application requirements. Besides this a short introduction is given into the vacuum carburizing process and the high-pressure gas quenching technology.

  2. Very Low-Cost, Rugged, High-Vacuum System for Mass Spectrometers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA, the DoD, DHS, and commercial industry have a pressing need for miniaturized, rugged, low-cost, high vacuum systems. Recent advances in sensor technology at...

  3. Very Low-Cost, Rugged, High-Vacuum System for Mass Spectrometers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA, DoD, DHS, and commercial industry have a pressing need for miniaturized, rugged, low-cost high-vacuum systems. Recent advances in sensor technology at NASA and...

  4. Development of precision numerical controlled high vacuum electron beam welding machine

    CERN Document Server

    Li Shao Lin

    2002-01-01

    The structure, main technical parameters and characteristics of the precision numerical controlled high vacuum electron beam welding machine are introduced. The design principle, some features and solutions to some key technique problems of this new type machine are described

  5. Numerical Simulation of High-current Vacuum Arc in Short Gap%Numerical Simulation of High-current Vacuum Arc in Short Gap

    Institute of Scientific and Technical Information of China (English)

    XIANG Chuan; LIAO Min-fu; DONG Hua-jun; HUANG Zhi-hui; ZOU Ji-yan

    2011-01-01

    The plasma status of vacuum arc before arc current zero, has a great influence on the interruption perform- ance of the vacuum circuit breakers. In this paper, a vacuum arc model in a short gap was established based on the magnet hydrodynamic (MHD) and a common computational fluid dynamics (CFD) software was utilized to specially investigate the properties of this arc. The spatial distributions of plasma pressure, plasma density, ion axial velocity, and axial current density in front of the anode surface of vacuum arc in this case were obtained. Simulation results in- dicate that: from the cathode to the anode, both of the plasma pressure and the plasma density increase gradually, and the plasma axial velocity decreases gradually; the axial current density in front of anode has a large radial gradient, and the maximum value is still smaller than the threshold current density for the anode-spot formation, thus, the anode is still passive. The comparison between the plasma density of simulation and the CMOS images taken by the high-speed camera indicates that they are in reasonable agreement with each other and demonstrates the feasibility of the vacuum arc model.

  6. W(310) cold-field emission characteristics reflecting the vacuum states of an extreme high vacuum electron gun

    Science.gov (United States)

    Cho, Boklae; Shigeru, Kokubo; Oshima, Chuhei

    2013-01-01

    An extremely high vacuum cold-field electron emission (CFE) gun operating at pressures ranging from ˜10-8 Pa to ˜10-10 Pa was constructed. Only the CFE current emitting from W(310) surfaces revealed the existence of a "stable region" with high current angular density just after tip flash heating. In the "stable region," the CFE current was damped very slowly. The presence of non-hydrogen gas eliminated this region from the plot. Improvement of the vacuum prolonged the 90% damping time of the CFE current from ˜10 min to 800 min. The current angular density I' of CFE current was 60 and 250 μA/sr in the "stable region" for total CFE currents of 10 and 50 μA, respectively. These results were about three times larger than I' when measured after the complete damping of the CFE current. The CFE gun generated bright scanning transmission electron microscopy images of a carbon nanotube at 30 kV.

  7. High ion charge states in a high-current, short-pulse, vacuum ARC ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Anders, A.; Brown, I.; MacGill, R.; Dickinson, M. [Lawrence Berkeley National Lab., CA (United States)

    1996-08-01

    Ions of the cathode material are formed at vacuum arc cathode spots and extracted by a grid system. The ion charge states (typically 1-4) depend on the cathode material and only little on the discharge current as long as the current is low. Here the authors report on experiments with short pulses (several {mu}s) and high currents (several kA); this regime of operation is thus approaching a more vacuum spark-like regime. Mean ion charge states of up to 6.2 for tungsten and 3.7 for titanium have been measured, with the corresponding maximum charge states of up to 8+ and 6+, respectively. The results are discussed in terms of Saha calculations and freezing of the charge state distribution.

  8. Different approach to pulsed high-voltage vacuum-insulation design

    Directory of Open Access Journals (Sweden)

    John G. Leopold

    2007-06-01

    Full Text Available A theoretical methodology promising improved design of vacuum insulation in high-voltage pulsed-power systems is described. It consists of shaping the electromagnetic fields within the system in such a way that charged particles which can in principle initiate vacuum surface breakdown are deflected away from the insulator surface, and secondary electrons, if emitted, are prevented from restriking the surface. Thus, vacuum surface breakdown is prevented before it is able to develop. Our methodology is presented here by a set of case studies.

  9. Preparation of high-purity bismuth by sulphur deleadization in vacuum distillation

    Institute of Scientific and Technical Information of China (English)

    熊利芝; 何则强; 刘文萍; 麻成金; 戴永年

    2004-01-01

    The feasibility of separation of impurities in refined bismuth and sulphur deleadization with vacuum distillation was studied theoretically. Experimental studies on sulphur deleadization were carried out under vacuum.The influences of amount of sulphur, distillation temperature, vacuum degree and distillation time on deleadization were investigated and an optimal technical condition was achieved. The content of lead in refined bismuth can be decreased from 30 μg/g to 0.21 μg/g, which has reached the level of "5N" high-purity bismuth. Other impurities in refined bismuth can be also removed effectively under certain conditions.

  10. LHCb: Design of a Highly Optimised Vacuum Chamber Support for the LHCb Experiment

    CERN Multimedia

    Leduc, L; Veness, R

    2011-01-01

    The beam vacuum chamber in the LHCb experimental area passes through the centre of a large aperture dipole magnet. The vacuum chamber and all its support systems lie in the acceptance of the detector, so must be highly optimised for transparency to particles. As part of the upgrade programme for the LHCb vacuum system, the support system has been re-designed using advanced lightweight materials. In this paper we discuss the physics motivation for the modifications, the criteria for the selection of materials and tests performed to qualify them for the particular environment of a particle physics experiment. We also present the design of the re-optimised support system.

  11. Study on the heat transfer of high-vacuum-multilayer-insulation tank after sudden, catastrophic loss of insulating vacuum

    Science.gov (United States)

    Xie, G. F.; Li, X. D.; Wang, R. S.

    2010-10-01

    One of the worst accidents that may occur in a high-vacuum-multilayer-insulation (HVMLI) cryogenic tank is a sudden, catastrophic loss of insulating vacuum (SCLIV). There is no doubt that the gases leaking into the insulation jacket have some influence on the heat transfer process of it. However, this issue has not been thoroughly studied so far. In this paper, a test rig was built up and experiments were conducted using a SCLIV cryogenic tank and with nitrogen, helium and air as the working medium, respectively. The venting rates of the tank and temperature in the insulation jacket were measured respectively after the three different gases leaking into the jacket. A heat transfer model describing the heat transfer process of a SCLIV tank was also presented. The calculated results using this model were compared against the experimental data. It is found that the heat transfer performance of the HVMLI cryogenic tank after SCLIV is strong relevant to the type of gas leaking into the insulation jacket.

  12. Influence of a high vacuum on the precise positioning using an ultrasonic linear motor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Wan-Soo; Lee, Dong-Jin; Lee, Sun-Kyu [School of Mechatronics, Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Gwangju 500-712 (Korea, Republic of)

    2011-01-15

    This paper presents an investigation of the ultrasonic linear motor stage for use in a high vacuum environment. The slider table is driven by the hybrid bolt-clamped Langevin-type ultrasonic linear motor, which is excited with its different modes of natural frequencies in both lateral and longitudinal directions. In general, the friction behavior in a vacuum environment becomes different from that in an environment of atmospheric pressure and this difference significantly affects the performance of the ultrasonic linear motor. In this paper, to consistently provide stable and high power of output in a high vacuum, frequency matching was conducted. Moreover, to achieve the fine control performance in the vacuum environment, a modified nominal characteristic trajectory following control method was adopted. Finally, the stage was operated under high vacuum condition, and the operating performances were investigated compared with that of a conventional PI compensator. As a result, robustness of positioning was accomplished in a high vacuum condition with nanometer-level accuracy.

  13. Simulation of Electron Beam Dynamics in a Nonmagnetized High-Current Vacuum Diode

    CERN Document Server

    Anishchenko, Sergey

    2016-01-01

    The electron beam dynamics in a nonmagnetized high-current vacuum diode is analyzed for different cathode-anode gap geometries. The conditions enabling to achieve the minimal {initial} momentum spread in the electron beam are found out. A drastic rise of current density in a vacuum diode with a ring-type cathode is described. The effect is shown to be caused by electrostatic repulsion.

  14. Improving the vacuum-infusion process to manufacture high quality structural composite for the aeronautic market

    OpenAIRE

    Oliveira, Luís; Nunes, J. P.; Ferreira, F

    2014-01-01

    In last years, the vacuum-infusion processing method is being replacing successfully autoclave technologies to manufacture advanced composite structures, namely, the carbon-fibre reinforced plastic (CFRP) ones, for aeronautical and aerospace applications. The high investment associated with autoclave “prepreg” manufacturing has prompted interest in the use of alternative vacuum-infusion technologies that proven to be much more cost-effective processing methods. The present work presents, desc...

  15. Upgrade of RHIC Vacuum Systems for High Luminosity Operation

    CERN Document Server

    Hseuh Hsiao Chaun; Smart, Loralie; Todd, Robert J; Weiss, Daniel

    2005-01-01

    With increasing ion beam intensity during recent RHIC operations, pressure rises of several decades were observed at most room temperature sections and at a few cold sections. The pressure rises are associated with electron multi-pacting, electron stimulated desorption and beam ion induced desorption and have been one of the major intensity and luminosity limiting factors for RHIC. Improvement of the warm sections has been carried out in the last few years. Extensive in-situ bakes, additional UHV pumping, anti-grazing ridges and beam tube solenoids have been implemented. Several hundred meters of NEG coated beam pipes have been installed and activated. Vacuum monitoring and interlock were enhanced to reduce premature beam aborts. Preliminary measures, such as pumping before cool down to reduce monolayer condensates, were also taken to suppress the pressure rises in the cold sections. The effectiveness of these measures in reducing the pressure rises during machine studies and during physics runs are discussed...

  16. Gas and RRR Distribution in High Purity Niobium EB Welded in Ultra-High Vacuum.

    OpenAIRE

    Anakhov, S.; Singer, X.; W. Singer; Wen, H.

    2006-01-01

    Electron beam (EB) welding in UHV (ultra-high vacuum, 10(-5) divided by 10(-8) mbar) is applied in the standard fabrication of high gradient niobium superconducting radio frequency (SRF) cavities of TESLA design. The quality of EB welding is critical for cavity performance. Experimental data of gas content (H-2, O-2, N-2) and RRR (residual resistivity ratio) measurements in niobium (Nb) welding seams are presented. EB welding in UHV conditions allow to preserve low gas content (1 divided by 3...

  17. Vacuum-integrated electrospray deposition for highly reliable polymer thin film.

    Science.gov (United States)

    Park, Soohyung; Lee, Younjoo; Yi, Yeonjin

    2012-10-01

    Vacuum electrospray deposition (ESD) equipment was designed to prepare polymer thin films. The polymer solution can be injected directly into vacuum system through multi-stage pumping line, so that the solvent residues and ambient contaminants are highly reduced. To test the performance of ESD system, we fabricated organic photovoltaic cells (OPVCs) by injecting polymer solution directly onto the substrate inside a high vacuum chamber. The OPVC fabricated has the structure of Al∕P3HT:PCBM∕PEDOT:PSS∕ITO and was optimized by varying the speed of solution injection and concentration of the solution. The power conversion efficiency (PCE) of the optimized OPVC is 3.14% under AM 1.5G irradiation without any buffer layer at the cathode side. To test the advantages of the vacuum ESD, we exposed the device to atmosphere between the deposition steps of the active layer and cathode. This showed that the PCE of the vacuum processed device is 24% higher than that of the air exposed device and confirms the advantages of the vacuum prepared polymer film for high performance devices.

  18. A highly miniaturized vacuum package for a trapped ion atomic clock

    Energy Technology Data Exchange (ETDEWEB)

    Schwindt, Peter D. D., E-mail: pschwin@sandia.gov; Jau, Yuan-Yu; Partner, Heather; Casias, Adrian; Wagner, Adrian R.; Moorman, Matthew; Manginell, Ronald P. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Kellogg, James R.; Prestage, John D. [Jet Propulsion Laboratory, Pasadena, California 91109 (United States)

    2016-05-15

    We report on the development of a highly miniaturized vacuum package for use in an atomic clock utilizing trapped ytterbium-171 ions. The vacuum package is approximately 1 cm{sup 3} in size and contains a linear quadrupole RF Paul ion trap, miniature neutral Yb sources, and a non-evaporable getter pump. We describe the fabrication process for making the Yb sources and assembling the vacuum package. To prepare the vacuum package for ion trapping, it was evacuated, baked at a high temperature, and then back filled with a helium buffer gas. Once appropriate vacuum conditions were achieved in the package, it was sealed with a copper pinch-off and was subsequently pumped only by the non-evaporable getter. We demonstrated ion trapping in this vacuum package and the operation of an atomic clock, stabilizing a local oscillator to the 12.6 GHz hyperfine transition of {sup 171}Y b{sup +}. The fractional frequency stability of the clock was measured to be 2 × 10{sup −11}/τ{sup 1/2}.

  19. HIGH-TEMPERATURE VACUUM CEMENTATION – THE RESERVE TO REDUCE THE ENERGY INTENSITY OF MANUFACTURE AND IMPROVE THE QUALITY OF TRANSMISSIONS GEARWHEELS OF HIGH-ENERGY MACHINES

    Directory of Open Access Journals (Sweden)

    A. A. Shipko

    2016-01-01

    Full Text Available Results of research of influence of high-temperature vacuum chemical heat treatment on the amount of grain structural steels are presented. The efficiency of hereditary fine-grained steel for high temperature vacuum carburizing are shown.

  20. Thermo-Mechanical Stress in High-Frequency Vacuum Electron Devices

    Science.gov (United States)

    Gamzina, Diana; Luhmann, Neville C.; Ravani, Bahram

    2017-01-01

    Analysis of the thermo-mechanical performance of high-frequency vacuum electron devices is essential to the advancement of RF sources towards high-power generation. Operation in an ultra-high vacuum environment, space restricting magnetic focusing, and limited material options are just some of the constraints that complicate thermal management in a high-power VED. An analytical method for evaluating temperature, stress, and deformation distribution in thin vacuum-to-cooling walls is presented, accounting for anisotropic material properties. Thin plate geometry is used and analytical expressions are developed for thermo-mechanical analysis that includes the microstructure effects of grain orientations. The method presented evaluates the maximum allowable heat flux that can be used to establish the power-handling limitation of high-frequency VEDs prior to full-scale design, accelerating time-to-manufacture.

  1. Thermo-Mechanical Stress in High-Frequency Vacuum Electron Devices

    Science.gov (United States)

    Gamzina, Diana; Luhmann, Neville C.; Ravani, Bahram

    2016-09-01

    Analysis of the thermo-mechanical performance of high-frequency vacuum electron devices is essential to the advancement of RF sources towards high-power generation. Operation in an ultra-high vacuum environment, space restricting magnetic focusing, and limited material options are just some of the constraints that complicate thermal management in a high-power VED. An analytical method for evaluating temperature, stress, and deformation distribution in thin vacuum-to-cooling walls is presented, accounting for anisotropic material properties. Thin plate geometry is used and analytical expressions are developed for thermo-mechanical analysis that includes the microstructure effects of grain orientations. The method presented evaluates the maximum allowable heat flux that can be used to establish the power-handling limitation of high-frequency VEDs prior to full-scale design, accelerating time-to-manufacture.

  2. Vacuum encapsulated, high temperature diamond amplified cathode capsule and method for making same

    Science.gov (United States)

    Rao, Triveni; Walsh, Josh; Gangone, Elizabeth

    2015-12-29

    A vacuum encapsulated, hermetically sealed cathode capsule for generating an electron beam of secondary electrons, which generally includes a cathode element having a primary emission surface adapted to emit primary electrons, an annular insulating spacer, a diamond window element comprising a diamond material and having a secondary emission surface adapted to emit secondary electrons in response to primary electrons impinging on the diamond window element, a first high-temperature solder weld disposed between the diamond window element and the annular insulating spacer and a second high-temperature solder weld disposed between the annular insulating spacer and the cathode element. The cathode capsule is formed by a high temperature weld process under vacuum such that the first solder weld forms a hermetical seal between the diamond window element and the annular insulating spacer and the second solder weld forms a hermetical seal between the annular spacer and the cathode element whereby a vacuum encapsulated chamber is formed within the capsule.

  3. Development of a high vacuum sample preparation system for helium mass spectrometer

    Science.gov (United States)

    Kumar, P.; Das, N. K.; Mallik, C.; Bhandari, R. K.

    2012-11-01

    A high vacuum sample preparation system for the 3He/4He ratio mass spectrometer (Helix SFT) has been developed to remove all the gaseous constituents excluding helium from the field gases. The sample preparation system comprises of turbo molecular pump, ion pump, zirconium getter, pipettes and vacuum gauges with controller. All these are fitted with cylindrical SS chamber using all metal valves. The field samples are initially treated with activated charcoal trap immersed in liquid nitrogen to cutoff major impurities and moisture present in the sample gas. A sample of 5 ml is collected out of this stage at a pressure of 10-2 mbar. This sample is subsequently purified at a reduced pressure of 10-7 mbar before it is injected into the ion source of the mass spectrometer. The sample pressure was maintained below 10-7 mbar with turbo molecular vacuum pumps and ion pumps. The sample gas passes through several getter elements and a cold finger with the help of manual high vacuum valves before it is fed to the mass spectrometer. Thus the high vacuum sample preparation system introduces completely clean, dry and refined helium sample to the mass spectrometer for best possible analysis of isotopic ratio of helium.

  4. Gas and RRR distribution in high purity Niobium EB welded in Ultra-High Vacuum

    Science.gov (United States)

    Anakhov, S.; Singer, X.; Singer, W.; Wen, H.

    2006-05-01

    Electron beam (EB) welding in UHV (ultra-high vacuum, 10-5÷10-8 mbar) is applied in the standard fabrication of high gradient niobium superconducting radio frequency (SRF) cavities of TESLA design. The quality of EB welding is critical for cavity performance. Experimental data of gas content (H2, O2, N2) and RRR (residual resistivity ratio) measurements in niobium (Nb) welding seams are presented. EB welding in UHV conditions allow to preserve low gas content (1÷3 wt. ppm hydrogen and 5÷7 ppm oxygen and nitrogen), essential for high values of RRR — 350÷400 units. Gas content redistribution in the electron beam welded and heat affected region take place in the welding process. Correlation between gas solubility parameters, RRR and thermal conductivity are presented. Mechanisms of gas solubility in EB welding process are discussed.

  5. Vacuum mechatronics

    Science.gov (United States)

    Hackwood, Susan; Belinski, Steven E.; Beni, Gerardo

    1989-01-01

    The discipline of vacuum mechatronics is defined as the design and development of vacuum-compatible computer-controlled mechanisms for manipulating, sensing and testing in a vacuum environment. The importance of vacuum mechatronics is growing with an increased application of vacuum in space studies and in manufacturing for material processing, medicine, microelectronics, emission studies, lyophylisation, freeze drying and packaging. The quickly developing field of vacuum mechatronics will also be the driving force for the realization of an advanced era of totally enclosed clean manufacturing cells. High technology manufacturing has increasingly demanding requirements for precision manipulation, in situ process monitoring and contamination-free environments. To remove the contamination problems associated with human workers, the tendency in many manufacturing processes is to move towards total automation. This will become a requirement in the near future for e.g., microelectronics manufacturing. Automation in ultra-clean manufacturing environments is evolving into the concept of self-contained and fully enclosed manufacturing. A Self Contained Automated Robotic Factory (SCARF) is being developed as a flexible research facility for totally enclosed manufacturing. The construction and successful operation of a SCARF will provide a novel, flexible, self-contained, clean, vacuum manufacturing environment. SCARF also requires very high reliability and intelligent control. The trends in vacuum mechatronics and some of the key research issues are reviewed.

  6. Attonewton force detection using microspheres in a dual-beam optical trap in high vacuum

    CERN Document Server

    Ranjit, Gambhir; Stutz, Jordan H; Cunningham, Mark; Geraci, Andrew A

    2015-01-01

    We describe the implementation of laser-cooled silica microspheres as force sensors in a dual-beam optical dipole trap in high vacuum. Using this system we have demonstrated trap lifetimes exceeding several days, attonewton force detection capability, and wide tunability in trapping and cooling parameters. Measurements have been performed with charged and neutral beads to calibrate the sensitivity of the detector. This work establishes the suitability of dual beam optical dipole traps for precision force measurement in high vacuum with long averaging times, and enables future applications including the study of gravitational inverse square law violations at short range, Casimir forces, acceleration sensing, and quantum opto-mechanics.

  7. Ultrasonic Spray Drying vs High Vacuum and Microwaves Technology for Blueberries

    Science.gov (United States)

    Candia-Muñoz, N.; Ramirez-Bunster, M.; Vargas-Hernández, Y.; Gaete-Garretón, L.

    Interest in high quality foods: good taste and a high content of nutrients with healthy beneficial effects are increasing. Fruits have good properties but, they are lost because the oxidation process, additionally, for different reasons a 40% of harvested fruit are lost. To conserve the fruit properties an ultrasonic assisted spray dryer was developed and tested, comparing its results with microwave-vacuum drying technology. Results did shown taste, color, smell, particle shape and size distribution better than the conventional one. The antioxidants conservation were quite good except in the anthocyanins, in which the microwave and vacuum technology shown best results.

  8. Ethanol production from food waste at high solids content with vacuum recovery technology.

    Science.gov (United States)

    Huang, Haibo; Qureshi, Nasib; Chen, Ming-Hsu; Liu, Wei; Singh, Vijay

    2015-03-18

    Ethanol production from food wastes does not only solve environmental issues but also provides renewable biofuels. This study investigated the feasibility of producing ethanol from food wastes at high solids content (35%, w/w). A vacuum recovery system was developed and applied to remove ethanol from fermentation broth to reduce yeast ethanol inhibition. A high concentration of ethanol (144 g/L) was produced by the conventional fermentation of food waste without a vacuum recovery system. When the vacuum recovery is applied to the fermentation process, the ethanol concentration in the fermentation broth was controlled below 100 g/L, thus reducing yeast ethanol inhibition. At the end of the conventional fermentation, the residual glucose in the fermentation broth was 5.7 g/L, indicating incomplete utilization of glucose, while the vacuum fermentation allowed for complete utilization of glucose. The ethanol yield for the vacuum fermentation was found to be 358 g/kg of food waste (dry basis), higher than that for the conventional fermentation at 327 g/kg of food waste (dry basis).

  9. Use of Polycarbonate Vacuum Vessels in High-Temperature Fusion-Plasma Research

    Energy Technology Data Exchange (ETDEWEB)

    B. Berlinger, A. Brooks, H. Feder, J. Gumbas, T. Franckowiak and S.A. Cohen

    2012-09-27

    Magnetic fusion energy (MFE) research requires ultrahigh-vacuum (UHV) conditions, primarily to reduce plasma contamination by impurities. For radiofrequency (RF)-heated plasmas, a great benefit may accrue from a non-conducting vacuum vessel, allowing external RF antennas which avoids the complications and cost of internal antennas and high-voltage high-current feedthroughs. In this paper we describe these and other criteria, e.g., safety, availability, design flexibility, structural integrity, access, outgassing, transparency, and fabrication techniques that led to the selection and use of 25.4-cm OD, 1.6-cm wall polycarbonate pipe as the main vacuum vessel for an MFE research device whose plasmas are expected to reach keV energies for durations exceeding 0.1 s

  10. Vacuum Outgassing Behavior of Carbon Nanotube Cathode with High-Intensity Pulsed Electron Emission

    Science.gov (United States)

    Shen, Yi; Zhang, Huang; Xia, Liansheng; Liu, Xingguang; Pan, Haifeng; Lv, Lu; Yang, Anmin; Shi, Jinshui; Zhang, Linwen; Deng, Jianjun

    2015-02-01

    Experimental investigations on the vacuum outgassing of a carbon nanotube (CNT) cathode with high-intensity pulsed electron emission on a 2 MeV linear induction accelerator injector are presented. Under the 1.60 MV diode voltage, the CNT cathode could provide 1.67 kA electron beam with the amount of outgassing of about 0.51 Pa·L. It is found that the amount of outgassing, which determines the cathode emission current, depends on the diode voltage and the vacuum.

  11. Thick-film technology for ultra high vacuum interfaces of micro-structured traps

    CERN Document Server

    Kaufmann, Delia; Baig, M Tanveer; Kaufmann, Peter; Asenwar, Eman; Johanning, Michael; Wunderlich, Christof

    2011-01-01

    We adopt thick-film technology to produce ultra high vacuum compatible interfaces for electrical signals. These interfaces permit voltages of hundreds of Volts and currents of several Amperes and allow for very compact vacuum setups, useful in quantum optics in general, and especially for quantum information and quantum simulations using miniaturized traps for ions or neutral atoms. Such printed circuits can also be useful as pure in-vacuum devices. We demonstrate a specific interface, which provides eleven current feedthroughs, more than 70 dc feedthroughs and a feedthrough for radio frequencies. We achieve a pressure in the low 1e-11mbar range and demonstrate the full functionality of the interface by trapping chains of cold ytterbium ions, which requires all of the signals mentioned above being present. In addition, a versatile multi-channel device for supplying precise time-dependent voltages has been developed.

  12. Ethanol production from food waste at high solid contents with vacuum recovery technology

    Science.gov (United States)

    Ethanol production from food wastes does not only solve the environmental issues but also provide renewable biofuel to partially substitute fossil fuels. This study investigated the feasibility of utilization of food wastes for producing ethanol at high solid contents (35%, w/w). Vacuum recovery sys...

  13. Direct vacuum inlet system enabling highly sensitive in-situ analysis of chemical reaction products

    DEFF Research Database (Denmark)

    Trimarco, Daniel Bøndergaard; Scott, Søren Bertelsen; Pedersen, Thomas

    , a capillary maintaining a controlled flow over a pressure drop to ultra-high vacuum, and inlet and outlet channels for an inert make up gas. The use of a direct inlet enables orders of magnitude higher sensitivity than differentially pumped systems without a loss in time response for volatile products, while...

  14. A vacuum spark ion source: High charge state metal ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Yushkov, G. Yu., E-mail: gyushkov@mail.ru; Nikolaev, A. G.; Frolova, V. P. [High Current Electronics Institute, Siberian Branch of the Russian Academy of Science, Tomsk 634055 (Russian Federation); Oks, E. M. [High Current Electronics Institute, Siberian Branch of the Russian Academy of Science, Tomsk 634055 (Russian Federation); Tomsk State University of Control System and Radioelectronics, Tomsk 634050 (Russian Federation)

    2016-02-15

    High ion charge state is often important in ion beam physics, among other reasons for the very practical purpose that it leads to proportionately higher ion beam energy for fixed accelerating voltage. The ion charge state of metal ion beams can be increased by replacing a vacuum arc ion source by a vacuum spark ion source. Since the voltage between anode and cathode remains high in a spark discharge compared to the vacuum arc, higher metal ion charge states are generated which can then be extracted as an ion beam. The use of a spark of pulse duration less than 10 μs and with current up to 10 kA allows the production of ion beams with current of several amperes at a pulse repetition rate of up to 5 pps. We have demonstrated the formation of high charge state heavy ions (bismuth) of up to 15 + and a mean ion charge state of more than 10 +. The physics and techniques of our vacuum spark ion source are described.

  15. A vacuum spark ion source: High charge state metal ion beams

    Science.gov (United States)

    Yushkov, G. Yu.; Nikolaev, A. G.; Oks, E. M.; Frolova, V. P.

    2016-02-01

    High ion charge state is often important in ion beam physics, among other reasons for the very practical purpose that it leads to proportionately higher ion beam energy for fixed accelerating voltage. The ion charge state of metal ion beams can be increased by replacing a vacuum arc ion source by a vacuum spark ion source. Since the voltage between anode and cathode remains high in a spark discharge compared to the vacuum arc, higher metal ion charge states are generated which can then be extracted as an ion beam. The use of a spark of pulse duration less than 10 μs and with current up to 10 kA allows the production of ion beams with current of several amperes at a pulse repetition rate of up to 5 pps. We have demonstrated the formation of high charge state heavy ions (bismuth) of up to 15 + and a mean ion charge state of more than 10 +. The physics and techniques of our vacuum spark ion source are described.

  16. Electron beam gun with kinematic coupling for high power RF vacuum devices

    Energy Technology Data Exchange (ETDEWEB)

    Borchard, Philipp

    2016-11-22

    An electron beam gun for a high power RF vacuum device has components joined by a fixed kinematic coupling to provide both precise alignment and high voltage electrical insulation of the components. The kinematic coupling has high strength ceramic elements directly bonded to one or more non-ductile rigid metal components using a high temperature active metal brazing alloy. The ceramic elements have a convex surface that mates with concave grooves in another one of the components. The kinematic coupling, for example, may join a cathode assembly and/or a beam shaping focus electrode to a gun stem, which is preferably composed of ceramic. The electron beam gun may be part of a high power RF vacuum device such as, for example, a gyrotron, klystron, or magnetron.

  17. Electron beam gun with kinematic coupling for high power RF vacuum devices

    Science.gov (United States)

    Borchard, Philipp

    2016-11-22

    An electron beam gun for a high power RF vacuum device has components joined by a fixed kinematic coupling to provide both precise alignment and high voltage electrical insulation of the components. The kinematic coupling has high strength ceramic elements directly bonded to one or more non-ductile rigid metal components using a high temperature active metal brazing alloy. The ceramic elements have a convex surface that mates with concave grooves in another one of the components. The kinematic coupling, for example, may join a cathode assembly and/or a beam shaping focus electrode to a gun stem, which is preferably composed of ceramic. The electron beam gun may be part of a high power RF vacuum device such as, for example, a gyrotron, klystron, or magnetron.

  18. Development of Deep Penetration Welding Technology with High Brightness Laser under Vacuum

    Science.gov (United States)

    Katayama, Seiji; Yohei, Abe; Mizutani, Masami; Kawahito, Yousuke

    The authors have developed a new chamber for laser welding under the low vacuum conditions achieved by using rotary pumps. High-power disk laser bead-on-plate welding was performed on Type 304 stainless steel or A5052 aluminium alloy plate at the powers of 10, 16 and 26 kW at various welding speeds under low vacuum. The sound welds of more than 50 and 70 mm in penetration depth could be produced in Type 304 at the pressure of 0.1 kPa, the speed of 0.3 m/min and the power of 16 kW and 26 kW, respectively. Similar penetration was achieved in A 5052 aluminum alloy. Welding phenomena under low vacuum were also understood by observing the behavior of a keyhole inlet, a molten pool, melt flows and a plume ejected from a keyhole through high speed video cameras. Low interaction between a laser beam and a plume under low vacuum was confirmed by using probe laser beam method.

  19. Proposal to Negotiate, without Competitive Tendering, a Contract for the Supply of Beryllium Ultra-High-Vacuum Chambers for the ALICE, ATLAS and CMS Vacuum Systems

    CERN Document Server

    2002-01-01

    This document concerns a contract to be placed, without competitive tendering, for the supply of UHV (ultra-high-vacuum) chambers for the ALICE, ATLAS and CMS vacuum systems. Following a market survey carried out among 12 firms in five Member States and two non-Member States, a call for tenders (IT-2926/LHC/LHC) was sent on 14 August 2002 to one firm, in a non-Member State. By the closing date, CERN had received one tender. The Finance Committee is invited to agree to the negotiation of a contract with BRUSH WELLMAN (US) for the supply of UHV chambers for the ALICE, ATLAS and CMS vacuum systems for an amount of 1 074 220 US dollars, (1 613 428 Swiss francs), not subject to revision. The rate of exchange used is that stipulated in the tender. The firm has indicated the following distribution by country of the contract value covered by this adjudication proposal: US - 100%.

  20. 板式蒸发式冷凝器传热传质的数值模拟%Numerical Simulation on Heat and Mass Transfer of Plate Evaporative Condenser

    Institute of Scientific and Technical Information of China (English)

    董俐言; 王宝龙; 石文星; 李先庭; 李志明; 谭栋

    2013-01-01

    Two-dimensional mathematical model of the heat and mass transfer process among refrigerant, cooling water and air in the plate evaporative condenser was established on the basis of energy and mass conservation. Distributions of cooling water temperature, air temperature and air humidity ratio are obtained. And then studies on influencing factors of plate evaporative condenser heat flux, i.e., air flow rate, cooling water spray density, air dry bulb temperature, wet bulb temperature and the condensing temperature were conducted. Simulation results were verified through experiments, and the error was less than 10%. The results showed that heat flux increased with increasing air flow rate, increasing condensing temperature and decreasing air wet bulb temperature, and is not relevant to air dry bulb temperature. With the increasing cooling water spray density, heat flux gradually increased and then kept constant. These conclusions are instructive for optimization design of plate evaporative condenser.%  根据能量守恒和质量守恒定律,对板式蒸发式冷凝器中制冷剂、冷却水与空气之间的传热传质过程,建立了热质交换过程的二维数学模型,由此分析板式蒸发式冷凝器中冷却水温度、空气温度和空气含湿量等参数的分布规律,以及空气流速、干湿球温度、冷却水喷淋密度和冷凝温度对板式蒸发式冷凝器热流密度的影响,并将模拟结果通过实验进行了验证,两者之间的误差在10%以内。研究表明:板式蒸发式冷凝器的热流密度随进口空气流速的增加而增大,随湿球温度的升高而减小,几乎不受进口空气干球温度的影响;热流密度随着冷却水喷淋密度的增加逐渐增大,但增大至一定量后不再对热流密度有明显影响;冷凝温度越高,其热流密度越大。上述结论对板式蒸发式冷凝器的优化设计具有指导意义。

  1. Preparation of High-Grade Powders from Tomato Paste Using a Vacuum Foam Drying Method.

    Science.gov (United States)

    Sramek, Martin; Schweiggert, Ralf Martin; van Kampen, Andreas; Carle, Reinhold; Kohlus, Reinhard

    2015-08-01

    We present a rapid and gentle drying method for the production of high-grade tomato powders from double concentrated tomato paste, comparing results with powders obtained by foam mat air drying and freeze dried powders. The principle of this method consists of drying tomato paste in foamed state at low temperatures in vacuum. The formulations were dried at temperatures of 50, 60, and 70 °C and vacuum of 200 mbar. Foam stability was affected by low serum viscosity and the presence of solid particles in tomato paste. Consequently, serum viscosity was increased by maltodextrin addition, yielding optimum stability at tomato paste:maltodextrin ratio of 2.4:1 (w/w) in dry matter. Material foamability was improved by addition of 0.5% (w/w, fresh weight) egg white. Because of solid particles in tomato paste, foam air filling had to be limited to critical air volume fraction of Φ = 0.7. The paste was first pre-foamed to Φ = 0.2 and subsequently expanded in vacuo. After drying to a moisture content of 5.6% to 7.5% wet base (w.b.), the materials obtained were in glassy state. Qualities of the resulting powders were compared with those produced by freeze and air drying. Total color changes were the least after vacuum drying, whereas air drying resulted in noticeable color changes. Vacuum foam drying at 50 °C led to insignificant carotenoid losses, being equivalent to the time-consuming freeze drying method. In contrast, air drying caused lycopene and β-carotene losses of 18% to 33% and 14% to 19% respectively. Thus, vacuum foam drying enables production of high-grade tomato powders being qualitatively similar to powders obtained by freeze drying.

  2. Numerical Simulation of the Thermal Conductivity of Thermal Insulation Pipe by Vacuum and High Pressure Argon Pre-filled

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    [Abstract]By analyzing the insulation effect of argon-filled tubing and vacuum-insulated tubing before and after hydrogen permeation respectively, a conclusion can be drawn that the insulated tubing filled with high pressure argon is better than the vacuum insulated tubing considering the lifetime and heat insulation effect.

  3. The high resolution vacuum ultraviolet absorption spectra of the group VI dihydrides and deuterides Rydberg series

    CERN Document Server

    Mayhew, C A

    1984-01-01

    The high resolution absorption spectra of the important group VI dihydrides and deuterides in the vacuum ultraviolet below, and up to, their first ionisation potentials are presented. These spectra were recorded using synchrotron radiation as the background light source in conjunction with a 3m normal incidence vacuum spectrograph, equipped with holographic gratings. Due to the nature of the originating orbital for the majority of optical transitions in the VUV well developed Rydberg series are observed. One particular series can be followed up to fairly high n, so that accurate values of the first ionisation potential are determined. The identifications of the Rydberg series are made from arguments relating to their oscillator strengths, quantum defects, symmetries and from comparisons with the spectra of the corresponding united atoms i.e. the inert gases. Examples of the symmetry assignments for Rydberg series from rotational band contour analyses of the lower Rydberg members for the H sub 2 S, H sub 2 Se ...

  4. Characterization of Magnetic Ni Clusters on Graphene Scaffold after High Vacuum Annealing

    CERN Document Server

    Zhang, Zhenjun; Grisafe, Benjamin; Lee, Ji Ung; Lloyd, James R

    2015-01-01

    Magnetic Ni nanoclusters were synthesized by electron beam deposition utilizing CVD graphene as a scaffold. The subsequent clusters were subjected to high vacuum (5-8 x10-7 torr) annealing between 300 and 600 0C. The chemical stability, optical and morphological changes were characterized by X-ray photoemission microscopy, Raman spectroscopy, atomic force microscopy and magnetic measurement. Under ambient exposure, nickel nanoparticles was observed to be oxidized quickly, forming antiferromagnetic nickel oxide. Here, we report that the majority of the oxidized nickel is in non-stoichiometric form and can be reduced under high vacuum at temperature as low as 300 0C. Importantly, the resulting annealed clusters are relatively stable and no further oxidation was detectable after three weeks of air exposure at room temperature.

  5. Project W-320 high vacuum 241-AY-102 annulus ventilation system operability test report

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, J.W.

    1998-03-12

    This report documents the test results of OTP-320-001, Tank 241-AY-102 Annulus Ventilation System Testing. Included in the appendices are: (1) Supporting documentation prepared to demonstrate the structural integrity of the tank at high annulus vacuum (<20 INWG), and (2) a report that identifies potential cross connections between the primary and annulus ventilation systems. These cross connections were verified to be eliminated prior to the start of testing.

  6. Vacuum Infusion Molding Process Part 1:VIMP Based on a High-Permeable Medium

    Institute of Scientific and Technical Information of China (English)

    ZHU Ying-dan; WANG Ji-hui; YANG Zui; TAN Hua

    2003-01-01

    The visualization experiments were carried out to investigate the permeability of the high-permeable medium (HPM) and the roles of the peel ply and the HPM in the mold filling.The influence of process parameters on mold filling is discussed.Furthermore,the whole vacuum infusion molding process (VIMP) procedure is introduced in detail taking the manufacture of a model boat for example.

  7. A Versatile High-Vacuum Cryo-transfer System for Cryo-microscopy and Analytics

    OpenAIRE

    Tacke, Sebastian; Krzyzanek, Vladislav; Nüsse, Harald; Wepf, Roger Albert; Klingauf, Jürgen; Reichelt, Rudolf

    2016-01-01

    Cryogenic microscopy methods have gained increasing popularity, as they offer an unaltered view on the architecture of biological specimens. As a prerequisite, samples must be handled under cryogenic conditions below their recrystallization temperature, and contamination during sample transfer and handling must be prevented. We present a high-vacuum cryo-transfer system that streamlines the entire handling of frozen-hydrated samples from the vitrification process to low temperature imaging fo...

  8. Characterization of magnetic Ni clusters on graphene scaffold after high vacuum annealing

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhenjun, E-mail: zzhang1@albany.edu; Matsubayashi, Akitomo, E-mail: norwegianwood.1984@gmail.com; Grisafe, Benjamin, E-mail: bgrisafe@albany.edu; Lee, Ji Ung, E-mail: jlee1@albany.edu; Lloyd, James R., E-mail: JLloyd@sunycnse.com

    2016-02-15

    Magnetic Ni nanoclusters were synthesized by electron beam deposition utilizing CVD graphene as a scaffold. The subsequent clusters were subjected to high vacuum (5−8 x10{sup −7} torr) annealing between 300 and 600 °C. The chemical stability, optical and morphological changes were characterized by X-ray photoemission microscopy, Raman spectroscopy, atomic force microscopy and magnetic measurement. Under ambient exposure, nickel nanoparticles were observed to be oxidized quickly, forming antiferromagnetic nickel oxide. Here, we report that the majority of the oxidized nickel is in non-stoichiometric form and can be reduced under high vacuum at temperature as low as 300 °C. Importantly, the resulting annealed clusters were relatively stable and no further oxidation was detectable after three weeks of air exposure at room temperature. - Highlights: • Random oriented nickel clusters were assembled on monolayer graphene scaffold. • Nickel oxide shell was effectively reduced at moderate temperature. • Coercivity of nickel clusters are greatly improved after high vacuum annealing.

  9. The surface topography of the choroid plexus. Environmental, low and high vacuum scanning electron microscopy.

    Science.gov (United States)

    Mestres, Pedro; Pütz, Norbert; Garcia Gómez de Las Heras, Soledad; García Poblete, Eduardo; Morguet, Andrea; Laue, Michael

    2011-05-01

    Environmental scanning electron microscopy (ESEM) allows the examination of hydrated and dried specimens without a conductive metal coating which could be advantageous in the imaging of biological and medical objects. The aim of this study was to assess the performance and benefits of wet-mode and low vacuum ESEM in comparison to high vacuum scanning electron microscopy (SEM) using the choroid plexus of chicken embryos as a model, an organ of the brain involved in the formation of cerebrospinal fluid in vertebrates. Specimens were fixed with or without heavy metals and examined directly or after critical point drying with or without metal coating. For wet mode ESEM freshly excised specimens without any pre-treatment were also examined. Conventional high vacuum SEM revealed the characteristic morphology of the choroid plexus cells at a high resolution and served as reference. With low vacuum ESEM of dried but uncoated samples the structure appeared well preserved but charging was a problem. It could be reduced by a short beam dwell time and averaging of images or by using the backscattered electron detector instead of the gaseous secondary electron detector. However, resolution was lower than with conventional SEM. Wet mode imaging was only possible with tissue that had been stabilized by fixation. Not all surface details (e.g. microvilli) could be visualized and other structures, like the cilia, were deformed. In summary, ESEM is an additional option for the imaging of bio-medical samples but it is problematic with regard to resolution and sample stability during imaging. Copyright © 2011 Elsevier GmbH. All rights reserved.

  10. Monte Carlo simulations of ultra high vacuum and synchrotron radiation for particle accelerators

    CERN Document Server

    AUTHOR|(CDS)2082330; Leonid, Rivkin

    With preparation of Hi-Lumi LHC fully underway, and the FCC machines under study, accelerators will reach unprecedented energies and along with it very large amount of synchrotron radiation (SR). This will desorb photoelectrons and molecules from accelerator walls, which contribute to electron cloud buildup and increase the residual pressure - both effects reducing the beam lifetime. In current accelerators these two effects are among the principal limiting factors, therefore precise calculation of synchrotron radiation and pressure properties are very important, desirably in the early design phase. This PhD project shows the modernization and a major upgrade of two codes, Molflow and Synrad, originally written by R. Kersevan in the 1990s, which are based on the test-particle Monte Carlo method and allow ultra-high vacuum and synchrotron radiation calculations. The new versions contain new physics, and are built as an all-in-one package - available to the public. Existing vacuum calculation methods are overvi...

  11. Initiation of vacuum insulator surface high-voltage flashover with electrons produced by laser illumination

    Science.gov (United States)

    Krasik, Ya. E.; Leopold, J. G.

    2015-08-01

    In this paper, experiments are described in which cylindrical vacuum insulator samples and samples inclined at 45° relative to the cathode were stressed by microsecond timescale high-voltage pulses and illuminated by focused UV laser beam pulses. In these experiments, we were able to distinguish between flashover initiated by the laser producing only photo-electrons and when plasma is formed. It was shown that flashover is predominantly initiated near the cathode triple junction. Even dense plasma formed near the anode triple junction does not necessarily lead to vacuum surface flashover. The experimental results directly confirm our conjecture that insulator surface breakdown can be avoided by preventing its initiation [J. G. Leopold et al., Phys. Rev. ST Accel. Beams 10, 060401 (2007)] and complement our previous experimental results [J. Z. Gleizer et al., IEEE Trans. Dielectr. Electr. Insul. 21, 2394 (2014) and J. Z. Gleizer et al., J. Appl. Phys. 117, 073301 (2015)].

  12. Initiation of vacuum insulator surface high-voltage flashover with electrons produced by laser illumination

    Energy Technology Data Exchange (ETDEWEB)

    Krasik, Ya. E.; Leopold, J. G. [Physics Department, Technion, Haifa 32000 (Israel)

    2015-08-15

    In this paper, experiments are described in which cylindrical vacuum insulator samples and samples inclined at 45° relative to the cathode were stressed by microsecond timescale high-voltage pulses and illuminated by focused UV laser beam pulses. In these experiments, we were able to distinguish between flashover initiated by the laser producing only photo-electrons and when plasma is formed. It was shown that flashover is predominantly initiated near the cathode triple junction. Even dense plasma formed near the anode triple junction does not necessarily lead to vacuum surface flashover. The experimental results directly confirm our conjecture that insulator surface breakdown can be avoided by preventing its initiation [J. G. Leopold et al., Phys. Rev. ST Accel. Beams 10, 060401 (2007)] and complement our previous experimental results [J. Z. Gleizer et al., IEEE Trans. Dielectr. Electr. Insul. 21, 2394 (2014) and J. Z. Gleizer et al., J. Appl. Phys. 117, 073301 (2015)].

  13. Probing vacuum birefringence using x-ray free electron and optical high-intensity lasers

    CERN Document Server

    Karbstein, Felix

    2016-01-01

    Vacuum birefringence is one of the most striking predictions of strong field quantum electrodynamics: Probe photons traversing a strong field region can indirectly sense the applied "pump" electromagnetic field via quantum fluctuations of virtual charged particles which couple to both pump and probe fields. This coupling is sensitive to the field alignment and can effectively result in two different indices of refraction for the probe photon polarization modes giving rise to a birefringence phenomenon. In this article we perform a dedicated theoretical analysis of the proposed discovery experiment of vacuum birefringence at a x-ray free electron laser/optical high-intensity laser facility. Describing both pump and probe laser pulses realistically in terms of their macroscopic electromagnetic fields, we go beyond previous analyses by accounting for various effects not considered before in this context. Our study facilitates stringent quantitative predictions and optimizations of the signal in an actual experim...

  14. Probing vacuum birefringence using x-ray free electron and optical high-intensity lasers

    Science.gov (United States)

    Karbstein, Felix; Sundqvist, Chantal

    2016-07-01

    Vacuum birefringence is one of the most striking predictions of strong field quantum electrodynamics: Probe photons traversing a strong field region can indirectly sense the applied "pump" electromagnetic field via quantum fluctuations of virtual charged particles which couple to both pump and probe fields. This coupling is sensitive to the field alignment and can effectively result in two different indices of refraction for the probe photon polarization modes giving rise to a birefringence phenomenon. In this article, we perform a dedicated theoretical analysis of the proposed discovery experiment of vacuum birefringence at an x-ray free electron laser/optical high-intensity laser facility. Describing both pump and probe laser pulses realistically in terms of their macroscopic electromagnetic fields, we go beyond previous analyses by accounting for various effects not considered before in this context. Our study facilitates stringent quantitative predictions and optimizations of the signal in an actual experiment.

  15. Optimization of Multilayer Laminated Film and Absorbent of Vacuum Insulation Panel for Use at High Temperature

    Science.gov (United States)

    Araki, Kuninari; Echigoya, Wataru; Tsuruga, Toshimitsu; Kamoto, Daigorou; Matsuoka, Shin-Ichi

    For the energy saving regulation and larger capacity, Vacuum Insulation Panel (VIP) has been used in refrigerators with urethane foam in recent years. VIP for low temperature is constructed by laminated plastic film, using heat welding of each neighboring part for keeping vacuum, so that the performance decrement is very large under high temperature. But recently high efficiency insulation material is desired for high temperature water holding devices (automatic vending machine, heat pump water heater, electric hot-water pot water, etc.), and we especially focused on cost and ability of the laminated plastic film and absorbent for high temperature VIP. We measured the heatproof temperature of plastic films and checked the amount of water vapor and out coming gas on temperature-programmed adsorption in absorbent. These results suggest the suitable laminated film and absorbent system for VIP use at high temperature, and the long-term reliability was evaluated by measuring thermal conductivity of high temperature. As a result it was found that high-retort pouch of CPP (cast polypropylene film) and adding of aluminum coating are the most suitable materials for use in the welded layers of high-temperature VIPs (105°C).

  16. Investigation of vacuum properties of CuCrZr alloy for high-heat-load absorber

    Science.gov (United States)

    Shueh, C.; Chan, C. K.; Chang, C. C.; Sheng, I. C.

    2017-01-01

    The Taiwan Photon Source (TPS) uses high-heat-load (HHL) absorbers to protect downstream ultrahigh-vacuum chambers from overheating. In this work, we propose to use the CuCrZr alloy (ASTM C18150) for the HHL absorber body and the ConFlat flanges. We use the throughput method to measure the thermal outgassing rate and a helium leak detector to verify the vacuum seal between the CuCrZr alloy and stainless-steel flanges. The measured outgassing rate of the CuCrZr alloy was 5.8×10-10 Pa m/s after 72 h of pumping and decreased to 2.0 × 10-10 Pa m/s after 100 h of pumping. The leak rate through the vacuum seal between a CuCrZr flange and a stainless-steel flange was less than 1 × 10-10 Pa m3/s even after mounting and unmounting the flanges ten times and baking them at 250 °C. These results indicate that CuCrZr alloy is suitable for integrating HHL components with ConFlat CuCrZr flanges for the absorption of the synchrotron radiation generated by the TPS.

  17. Recent advances in high current vacuum arc ion sources for heavy ion fusion

    CERN Document Server

    Qi Nian Sheng; Prasad, R R; Krishnan, M S; Anders, A; Kwan, J; Brown, I

    2001-01-01

    For a heavy ion fusion induction linac driver, a source of heavy ions with charge states 1+-3+, approx 0.5 A current beams, approx 20 mu s pulse widths and approx 10 Hz repetition rates is required. Thermionic sources have been the workhorse for the Heavy Ion Fusion (HIF) program to date, but suffer from heating problems for large areas and contamination. They are limited to low (contact) ionization potential elements and offer relatively low ion fluxes with a charge state limited to 1+. Gas injection sources suffer from partial ionization and deleterious neutral gas effects. The above shortcomings of the thermionic ion sources can be overcome by a vacuum arc ion source. The vacuum arc ion source is a good candidate for HIF applications. It is capable of providing ions of various elements and different charge states in short and long pulse bursts and high beam current density. Under a Phase-I STTR from DOE, the feasibility of the vacuum arc ion source for the HIF applications was investigated. We have modifie...

  18. Development of fast heating electron beam annealing setup for ultra high vacuum chamber

    Science.gov (United States)

    Das, Sadhan Chandra; Majumdar, Abhijit; Katiyal, Sumant; Shripathi, T.; Hippler, R.

    2014-02-01

    We report the design and development of a simple, electrically low powered and fast heating versatile electron beam annealing setup (up to 1000 °C) working with ultra high vacuum (UHV) chamber for annealing thin films and multilayer structures. The important features of the system are constant temperature control in UHV conditions for the temperature range from room temperature to 1000 °C with sufficient power of 330 W, at constant vacuum during annealing treatment. It takes approximately 6 min to reach 1000 °C from room temperature (˜10-6 mbar) and 45 min to cool down without any extra cooling. The annealing setup consists of a UHV chamber, sample holder, heating arrangement mounted on suitable UHV electrical feed-through and electronic control and feedback systems to control the temperature within ±1 °C of set value. The outside of the vacuum chamber is cooled by cold air of 20 °C of air conditioning machine used for the laboratory, so that chamber temperature does not go beyond 50 °C when target temperature is maximum. The probability of surface oxidation or surface contamination during annealing is examined by means of x-ray photoelectron spectroscopy of virgin Cu sample annealed at 1000 °C.

  19. A new Design for an High Gain Vacuum Photomultiplier: The Silicon PMT Used as Amplification Stage

    Energy Technology Data Exchange (ETDEWEB)

    Barbarino, Giancarlo [Universita di Napoli ' Federico II' , Dipartimento di Scienze fisiche, via Cintia 80126 Napoli (Italy); Asmundis, Riccardo de; De Rosa, Gianfranca [Istituto Nazionale di fisica Nucleare, sezione di Napoli, Complesso di Monte S. Angelo Ed. 6, via Cintia 80126 Napoli (Italy); Fiorillo, Giuliana; Russo, Stefano [Universita di Napoli ' Federico II' , Dipartimento di Scienze fisiche, via Cintia 80126 Napoli (Italy)

    2009-12-15

    Photons detection will continue to be a channel of great interest in the High Energy Physics and Astroparticle Physics fields for medium and big scale experiments in the next future. Thus, new solutions for photon detectors, that overcome the current limits of classical photomultipliers, are welcomed. We propose an innovative design for a hybrid, modern, high gain Vacuum Silicon Photomultiplier Tube (VSiPMT) which is boosted by the recent Geiger-mode avalanche silicon photodiode (G-APD) for which a massive production is today available.

  20. Development of High Power Electron Beam Measuring and Analyzing System for Microwave Vacuum Electron Devices

    Science.gov (United States)

    Ruan, C. J.; Wu, X. L.; Li, Q. S.; Li, C. S.

    The measurement and analysis of high power electron beam during its formation and transmission are the basic scientific problems and key techniques for the development of high performance microwave vacuum electron devices, which are widely used in the fields of military weapon, microwave system and scientific instruments. In this paper, the dynamic parameters measurement and analysis system being built in Institute of Electronics, Chinese Academy of Sciences (IECAS) recently are introduced. The instrument are designed to determine the cross-section, the current density, and the energy resolution of the high power electron beam during its formation and transmission process, which are available both for the electron gun and the electron optics system respectively. Then the three dimension trajectory images of the electron beam can be rebuilt and display with computer controlled data acquisition and processing system easily. Thus, much more complicated structures are considered and solved completely to achieve its detection and analysis, such as big chamber with 10-6 Pa high vacuum system, the controlled detector movement system in axis direction with distance of 600 mm inside the vacuum chamber, the electron beam energy analysis system with high resolution of 0.5%, and the electron beam cross-section and density detector using the YAG: Ce crystal and CCD imaging system et al. At present, the key parts of the instrument have been finished, the cross-section experiment of the electron beam have been performed successfully. Hereafter, the instrument will be used to measure and analyze the electron beam with the electron gun and electron optics system for the single beam and multiple beam klystron, gyrotron, sheet beam device, and traveling wave tube etc. thoroughly.

  1. High vacuum tip-enhanced Raman spectroscope based on a scanning tunneling microscope

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Yurui [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P. O. Box 603-146, Beijing 100190 (China); Bionanophotonics, Department of Applied Physics, Chalmers University of Technology, Göteborg, SE 41296 (Sweden); Zhang, Zhenglong [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P. O. Box 603-146, Beijing 100190 (China); School of Physics and Information Technology, Shaanxi Normal University, 710062 Xi’an (China); Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena (Germany); Sun, Mengtao, E-mail: mtsun@iphy.ac.cn [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P. O. Box 603-146, Beijing 100190 (China)

    2016-03-15

    In this paper, we present the construction of a high-vacuum tip-enhanced Raman spectroscopy (HV-TERS) system that allows in situ sample preparation and measurement. A detailed description of the prototype instrument is presented with experimental validation of its use and novel ex situ experimental results using the HV-TERS system. The HV-TERS system includes three chambers held under a 10{sup −7} Pa vacuum. The three chambers are an analysis chamber, a sample preparation chamber, and a fast loading chamber. The analysis chamber is the core chamber and contains a scanning tunneling microscope (STM) and a Raman detector coupled with a 50 × 0.5 numerical aperture objective. The sample preparation chamber is used to produce single-crystalline metal and sub-monolayer molecular films by molecular beam epitaxy. The fast loading chamber allows ex situ preparation of samples for HV-TERS analysis. Atomic resolution can be achieved by the STM on highly ordered pyrolytic graphite. We demonstrate the measurement of localized temperature using the Stokes and anti-Stokes TERS signals from a monolayer of 1,2-benzenedithiol on a gold film using a gold tip. Additionally, plasmonic catalysis can be monitored label-free at the nanoscale using our device. Moreover, the HV-TERS experiments show simultaneously activated infrared and Raman vibrational modes, Fermi resonance, and some other non-linear effects that are not observed in atmospheric TERS experiments. The high spatial and spectral resolution and pure environment of high vacuum are beneficial for basic surface studies.

  2. Ultra-high vacuum compatible induction-heated rod casting furnace

    CERN Document Server

    Bauer, Andreas; Münzer, Wolfgang; Regnat, Alexander; Benka, Georg; Meven, Martin; Pedersen, Björn; Pfleiderer, Christian

    2016-01-01

    We report the design of a radio-frequency induction-heated rod casting furnace that permits the preparation of polycrystalline ingots of intermetallic compounds under ultra-high vacuum compatible conditions. The central part of the system is a bespoke water-cooled Hukin crucible supporting a casting mold. Depending on the choice of mold, typical rods have a diameter between 6 mm and 10 mm and a length up to 90 mm, suitable for single-crystal growth by means of float-zoning. The setup is all-metal sealed and may be baked out. We find that the resulting ultra-high vacuum represents an important precondition for processing compounds with high vapor pressures under a high-purity argon atmosphere up to 3 bar. Using the rod casting furnace, we succeeded to prepare large high-quality single crystals of two half-Heusler compounds, namely the itinerant antiferromagnet CuMnSb and the half-metallic ferromagnet NiMnSb.

  3. Ultra-high vacuum surface analysis study of rhodopsin incorporation into supported lipid bilayers.

    Science.gov (United States)

    Michel, Roger; Subramaniam, Varuni; McArthur, Sally L; Bondurant, Bruce; D'Ambruoso, Gemma D; Hall, Henry K; Brown, Michael F; Ross, Eric E; Saavedra, S Scott; Castner, David G

    2008-05-06

    Planar supported lipid bilayers that are stable under ambient atmospheric and ultra-high-vacuum conditions were prepared by cross-linking polymerization of bis-sorbylphosphatidylcholine (bis-SorbPC). X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were employed to investigate bilayers that were cross-linked using either redox-initiated radical polymerization or ultraviolet photopolymerization. The redox method yields a more structurally intact bilayer; however, the UV method is more compatible with incorporation of transmembrane proteins. UV polymerization was therefore used to prepare cross-linked bilayers with incorporated bovine rhodopsin, a light-activated, G-protein-coupled receptor (GPCR). A previous study (Subramaniam, V.; Alves, I. D.; Salgado, G. F. J.; Lau, P. W.; Wysocki, R. J.; Salamon, Z.; Tollin, G.; Hruby, V. J.; Brown, M. F.; Saavedra, S. S. J. Am. Chem. Soc. 2005, 127, 5320-5321) showed that rhodopsin retains photoactivity after incorporation into UV-polymerized bis-SorbPC, but did not address how the protein is associated with the bilayer. In this study, we show that rhodopsin is retained in supported bilayers of poly(bis-SorbPC) under ultra-high-vacuum conditions, on the basis of the increase in the XPS nitrogen concentration and the presence of characteristic amino acid peaks in the ToF-SIMS data. Angle-resolved XPS data show that the protein is inserted into the bilayer, rather than adsorbed on the bilayer surface. This is the first study to demonstrate the use of ultra-high-vacuum techniques for structural studies of supported proteolipid bilayers.

  4. Case report of nipple shield trauma associated with breastfeeding an infant with high intra-oral vacuum.

    Science.gov (United States)

    Perrella, Sharon L; Lai, Ching T; Geddes, Donna T

    2015-07-26

    Nipple pain is associated with early cessation of breastfeeding and may be caused by high intra-oral vacuum. However identification of high intra-oral vacuum is typically restricted to the research setting. This is the first reported case of an infant with high intra-oral vacuum that was clinically identified through a specific pattern of nipple trauma associated with nipple shield use. Knowledge of clinical signs associated with high intra-oral vacuum may facilitate early recognition of this unusual breastfeeding challenge. The mother of an exclusively breastfed 3 month old infant had severe bilateral nipple pain with minimal trauma that persisted from birth. The nipples were not misshapen immediately after breastfeeding and adjustments to infant attachment at the breast did not attenuate the pain. Examination of the infant's oral anatomy was unremarkable with no ankyloglossia present. Microbiological cultures of nipple swabs and breast milk were negative for bacterial and fungal growth, and prescribed antimicrobial treatments did not reduce the nipple pain. Mild blanching and erythema of the nipples were occasionally observed, and were not consistent with nipple vasospasm. Nipple shields were used regularly as they modified the pain, although this resulted in blisters that corresponded with the nipple shield holes. Measurement of infant intra-oral vacuum during breastfeeding confirmed intra-oral vacuum up to 307 % higher than reference values. Breastfeeding gradually became less painful, and after 6 months was completely comfortable. High intra-oral vacuum is difficult to assess in the clinical setting and is likely an under-reported cause of early weaning that is not well understood. This original case report highlights high intra-oral vacuum as at differential diagnosis to be considered by health professionals when evaluating mothers experiencing strong nipple pain during the initiation of breastfeeding. A clinical screening tool is needed to enable prompt

  5. High Contrast Vacuum Nuller Testbed (VNT) Contrast, Performance and Null Control

    Science.gov (United States)

    Lyon, Richard G.; Clampin, Mark; Petrone, Peter; Mallik, Udayan; Madison, Timothy; Bolcar, Matthew R.

    2012-01-01

    Herein we report on our Visible Nulling Coronagraph high-contrast result of 109 contrast averaged over a focal planeregion extending from 14 D with the Vacuum Nuller Testbed (VNT) in a vibration isolated vacuum chamber. TheVNC is a hybrid interferometriccoronagraphic approach for exoplanet science. It operates with high Lyot stopefficiency for filled, segmented and sparse or diluted-aperture telescopes, thereby spanning the range of potential futureNASA flight telescopes. NASAGoddard Space Flight Center (GSFC) has a well-established effort to develop the VNCand its technologies, and has developed an incremental sequence of VNC testbeds to advance this approach and itsenabling technologies. These testbeds have enabled advancement of high-contrast, visible light, nulling interferometry tounprecedented levels. The VNC is based on a modified Mach-Zehnder nulling interferometer, with a W configurationto accommodate a hex-packed MEMS based deformable mirror, a coherent fiber bundle and achromatic phase shifters.We give an overview of the VNT and discuss the high-contrast laboratory results, the optical configuration, criticaltechnologies and null sensing and control.

  6. O-Ring sealing arrangements for ultra-high vacuum systems

    Science.gov (United States)

    Kim, Chang-Kyo; Flaherty, Robert

    1981-01-01

    An all metal reusable O-ring sealing arrangement for sealing two concentric tubes in an ultra-high vacuum system. An O-ring of a heat recoverable alloy such as Nitinol is concentrically positioned between protruding sealing rings of the concentric tubes. The O-ring is installed between the tubes while in a stressed martensitic state and is made to undergo a thermally induced transformation to an austenitic state. During the transformation the O-ring expands outwardly and contracts inwardly toward a previously sized austenitic configuration, thereby sealing against the protruding sealing rings of the concentric tubes.

  7. High Quality SiGe Layer Deposited by a New Ultrahigh Vacuum Chemical Vapor Deposition System

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An ultrahigh vacuum chemical vapor deposition (UHV/CVD) system is developed and the details of its construction and operation are reported. Using high purity SiH4 and GeH4 reactant gases,the Si0.82Ge0.18 layer is deposited at 550℃. With the measurements by double crystal X-ray diffraction (DCXRD), transmission electron microscopy (TEM) and Rutherford backscattering spectroscopy (RBS) techniques, it is shown that the crystalline quality of the SiGe layer is good,and the underlying SiGe/Si heterointerface is sharply defined.

  8. Development of high-vacuum planar magnetron sputtering using an advanced magnetic field geometry

    Energy Technology Data Exchange (ETDEWEB)

    Ohno, Takahiro; Yagyu, Daisuke; Saito, Shigeru, E-mail: saito@ee.kagu.tus.ac.jp; Ohno, Yasunori; Itoh, Masatoshi; Uhara, Yoshio; Miura, Tsutomu [Department of Electrical Engineering, Faculty of Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585 (Japan); Nakano, Hirofumi [Ikazuti Ltd., 3-28-10 Kikunodai, Chofu, Tokyo 182-0007 (Japan)

    2015-11-15

    A permanent magnet in a new magnetic field geometry (namely, with the magnetization in the radial direction) was fabricated and used for high-vacuum planar magnetron sputtering using Penning discharge. Because of the development of this magnet, the discharge current and deposition rate were increased two to three times in comparison with the values attainable with a magnet in the conventional geometry. This improvement was because the available space for effective discharge of the energetic electrons for the ionization increased because the magnetic field distribution increased in both the axial and radial directions of discharge.

  9. Preparation methodology and possible treatments for improved ceramics for high voltage vacuum applications

    CERN Document Server

    Tan, J

    1998-01-01

    The flashover characteristics of an insulator bridged high voltage vacuum gap can play an important role in the overall performance of a high voltage device, for example in the extreme environments of high energy particle accelerators. The detailed preparation of the insulators is, at present, governed by the commercial production methods and by standard bulk cleaning processes, which for a particular application may be far from optimum. The influence of the mechanical preparation, thermal history and particular cleaning technique have been investigated for commercially available alumina samples, with measurement of surface characteristics by scanning electron microscopy and laser diffraction, measurement of the secondary electron emission curve and analysis of the high voltage performance with the possibility of applied fields up to 200kV/cm. The results of the different measurements are discussed in the overall context of the problems encountered in the full sized high voltage devices, and suggestions are m...

  10. Extension of the shelf life of prawns (Penaeus japonicus) by vacuum packaging and high-pressure treatment.

    Science.gov (United States)

    López-Caballero, M E; Pérez-Mateos, M; Borderías, J A; Montero, P

    2000-10-01

    The present study has investigated the application of high pressures (200 and 400 MPa) in chilled prawn tails, both conventionally stored (air) and vacuum packaged. Vacuum packaging and high-pressure treatment did extend the shelf life of the prawn samples, although it did affect muscle color very slightly, giving it a whiter appearance. The viable shelf life of 1 week for the air-stored samples was extended to 21 days in the vacuum-packed samples, 28 days in the samples treated at 200 MPa, and 35 days in the samples pressurized at 400 MPa. Vacuum packaging checked the onset of blackening, whereas high-pressure treatment aggravated the problem. From a microbiological point of view, batches conventionally stored reached about 6 log CFU/g or even higher at 14 days. Similar figures were reached in total number of bacteria in vacuum-packed samples and in pressurized at 200-MPa samples at 21 days. When samples were pressurized at 400 MPa, total numbers of bacteria were below 5.5 log CFU/g at 35 days of storage. Consequently, a combination of vacuum packaging and high-pressure treatment would appear to be beneficial in prolonging freshness and preventing spotting.

  11. New Laboratory Technique to Determine Thermal Conductivity of Complex Regolith Simulants Under High Vacuum

    Science.gov (United States)

    Ryan, A. J.; Christensen, P. R.

    2016-12-01

    Laboratory measurements have been necessary to interpret thermal data of planetary surfaces for decades. We present a novel radiometric laboratory method to determine temperature-dependent thermal conductivity of complex regolith simulants under high vacuum and across a wide range of temperatures. Here, we present our laboratory method, strategy, and initial results. This method relies on radiometric temperature measurements instead of contact measurements, eliminating the need to disturb the sample with thermal probes. We intend to determine the conductivity of grains that are up to 2 cm in diameter and to parameterize the effects of angularity, sorting, layering, composition, and cementation. These results will support the efforts of the OSIRIS-REx team in selecting a site on asteroid Bennu that is safe and meets grain size requirements for sampling. Our system consists of a cryostat vacuum chamber with an internal liquid nitrogen dewar. A granular sample is contained in a cylindrical cup that is 4 cm in diameter and 1 to 6 cm deep. The surface of the sample is exposed to vacuum and is surrounded by a black liquid nitrogen cold shroud. Once the system has equilibrated at 80 K, the base of the sample cup is rapidly heated to 450 K. An infrared camera observes the sample from above to monitor its temperature change over time. We have built a time-dependent finite element model of the experiment in COMSOL Multiphysics. Boundary temperature conditions and all known material properties (including surface emissivities) are included to replicate the experiment as closely as possible. The Optimization module in COMSOL is specifically designed for parameter estimation. Sample thermal conductivity is assumed to be a quadratic or cubic polynomial function of temperature. We thus use gradient-based optimization methods in COMSOL to vary the polynomial coefficients in an effort to reduce the least squares error between the measured and modeled sample surface temperature.

  12. Eucentric four-axis ultrahigh vacuum goniometer for reflection high-energy electron diffraction applications

    Science.gov (United States)

    Schmehl, A.; Schulz, R. R.; Mannhart, J.

    2005-12-01

    The design and performance of a four-axis low-profile eucentric UHV goniometer for in situ reflection high-energy electron diffraction (RHEED) studies during film deposition is reported. The design provides one translational and three rotational degrees of freedom that are fully independent. Although developed to facilitate high-pressure RHEED during the growth of oxide thin films by pulsed laser deposition, this goniometer design is applicable to other UHV techniques including molecular beam epitaxy. The goniometer requires only a single DN 100 CF flange (6in. o.d., 100mm i.d.), making it suitable for small deposition systems, too. Samples, attached to a resistively heated holder, can be easily transferred on and off of the goniometer without breaking vacuum. The holder accommodates samples up to 10mm×10mm in size and allows them to be heated to 900°C in pure oxygen while being attached to the goniometer. Full eucentric motion of the hot sample is possible with a typical axis precision of mechanism is located in air, allowing the use of standard materials and lubricants, substantially reducing the in-vacuum mechanics, and increasing the precision, reliability, and robustness of the system.

  13. Deformation of contact surfaces in a vacuum interrupter after high-current interruptions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Haoran; Wang, Zhenxing, E-mail: zxwang@xjtu.edu.cn; Zhou, Zhipeng; Jiang, Yanjun; Wang, Jianhua; Geng, Yingsan; Liu, Zhiyuan [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China)

    2016-08-07

    In a high-current interruption, the contact surface in a vacuum interrupter might be severely damaged by constricted vacuum arcs causing a molten area on it. As a result, a protrusion will be initiated by a transient recovery voltage after current zero, enhancing the local electric field and making breakdowns occur easier. The objective of this paper is to simulate the deformation process on the molten area under a high electric field by adopting the finite element method. A time-dependent Electrohydrodynamic model was established, and the liquid-gas interface was tracked by the level-set method. From the results, the liquid metal can be deformed to a Taylor cone if the applied electric field is above a critical value. This value is correlated to the initial geometry of the liquid metal, which increases as the size of the liquid metal decreases. Moreover, the buildup time of a Taylor cone obeys the power law t = k × E{sup −3}, where E is the initial electric field and k is a coefficient related to the material property, indicating a temporal self-similar characteristic. In addition, the influence of temperature has little impact on the deformation but has great impact on electron emission. Finally, the possible reason to initiate a delayed breakdown is associated with the deformation. The breakdown does not occur immediately when the voltage is just applied upon the gap but is postponed to several milliseconds later when the tip is formed on the liquid metal.

  14. Deformation of contact surfaces in a vacuum interrupter after high-current interruptions

    Science.gov (United States)

    Wang, Haoran; Wang, Zhenxing; Zhou, Zhipeng; Jiang, Yanjun; Wang, Jianhua; Geng, Yingsan; Liu, Zhiyuan

    2016-08-01

    In a high-current interruption, the contact surface in a vacuum interrupter might be severely damaged by constricted vacuum arcs causing a molten area on it. As a result, a protrusion will be initiated by a transient recovery voltage after current zero, enhancing the local electric field and making breakdowns occur easier. The objective of this paper is to simulate the deformation process on the molten area under a high electric field by adopting the finite element method. A time-dependent Electrohydrodynamic model was established, and the liquid-gas interface was tracked by the level-set method. From the results, the liquid metal can be deformed to a Taylor cone if the applied electric field is above a critical value. This value is correlated to the initial geometry of the liquid metal, which increases as the size of the liquid metal decreases. Moreover, the buildup time of a Taylor cone obeys the power law t = k × E-3, where E is the initial electric field and k is a coefficient related to the material property, indicating a temporal self-similar characteristic. In addition, the influence of temperature has little impact on the deformation but has great impact on electron emission. Finally, the possible reason to initiate a delayed breakdown is associated with the deformation. The breakdown does not occur immediately when the voltage is just applied upon the gap but is postponed to several milliseconds later when the tip is formed on the liquid metal.

  15. Effects of water vapor in high vacuum chamber on the properties of HfO2 films

    Institute of Scientific and Technical Information of China (English)

    Bo Ling; Hongbo He; Jianda Shao

    2007-01-01

    The influence of water vapor content in high vacuum chamber during the coating process on physical properties of HfO2 films was investigated. Coatings were deposited on BK7 substrates by electron beam evaporation and photoelectric maximum control method. An in situ residual gas analyzer (RGA) was used to monitor the residual gas composition in the vacuum chamber. The optical properties, microstructure,absorption and laser-induced damage threshold (LIDT) of the samples were characterized by Lambda 900 spectrophotometer, X-ray diffraction (XRD), surface thermal lensing (STL) technique and 1064-nm Qswitched pulsed laser at a pulse duration of 12 ns respectively. It was found that a cold trap is an effective equipment to suppress water vapor in the vacuum chamber during the pumping process, and the coatings deposited in the vacuum atmosphere with relatively low water vapor composition show higher refractive index and smaller grain size. Meanwhile, the higher LIDT value is corresponding to lower absorbance.

  16. High Temperature Vacuum Annealing and Hydrogenation Modification of Exfoliated Graphite Nanoplatelets

    Directory of Open Access Journals (Sweden)

    Xiaobing Li

    2013-01-01

    Full Text Available Highly active defect sites on the edges of graphene automatically capture oxygen from air to form various oxygen groups. A two-step procedure to remove various oxygen functional groups from the defect sites of exfoliated graphene nanoplatelets (GNPs has been developed to reduce the atomic oxygen concentration from 9.5% to 4.8%. This two-step approach involves high temperature vacuum annealing followed by hydrogenation to protect the reduced edge carbon atoms from recombining with the atmospheric oxygen. The reduced GNPs exhibit decreased surface resistance and graphitic potential-dependent capacitance characteristics compared to the complex potential-dependent capacitance characteristics exhibited by the unreduced GNPs as a result of the removal of the oxygen functional groups present primarily at the edges. These reduced GNPs also exhibit high electrochemical cyclic stability for electrochemical energy storage applications.

  17. An Efficient, Movable Single-Particle Detector for Use in Cryogenic Ultra-High Vacuum Environments

    CERN Document Server

    Spruck, Kaija; Fellenberger, Florian; Grieser, Manfred; von Hahn, Robert; Klinkhamer, Vincent; Novotný, Oldřich; Schippers, Stefan; Vogel, Stephen; Wolf, Andreas; Krantz, Claude

    2014-01-01

    A compact, highly efficient single-particle counting detector for ions of keV/u kinetic energy, movable by a long-stroke mechanical translation stage, has been developed at the Max-Planck-Institut f\\"ur Kernphysik (Max Planck Institute for Nuclear Physics, MPIK). Both, detector and translation mechanics, can operate at ambient temperatures down to $\\sim$ 10 K and consist fully of ultra-high vacuum (UHV) compatible, high-temperature bakeable and non-magnetic materials. The set-up is designed to meet the technical demands of MPIK's Cryogenic Storage Ring (CSR). We present a series of functional tests that demonstrate full suitability for this application and characterise the set-up with regard to its particle detection efficiency.

  18. Vacuum stability and supersymmetry at high scales with two Higgs doublets

    Energy Technology Data Exchange (ETDEWEB)

    Bagnaschi, E.; Buchmueller, W.; Voigt, A.; Weiglein, G. [DESY Hamburg (Germany); Bruemmer, F. [Montpellier Univ. (France). Lab. Univers et Particules de Montpellier

    2016-02-15

    We investigate the stability of the electroweak vacuum for two-Higgs doublet models with a supersymmetric UV completion. The supersymmetry breaking scale is taken to be of the order of the grand unification scale. We first study the case where all superpartners decouple at this scale. We show that contrary to the Standard Model with one Higgs doublet, matching to the supersymmetric UV completion is possible if the low-scale model contains two Higgs doublets. In this case vacuum stability and experimental constraints point towards low values of tanβhigh scales when requiring a 125 GeV Higgs. Light neutral and charged higgsinos therefore emerge as a promising signature of a supersymmetric UV completion of the Standard Model at the grand unification scale.

  19. Simple, highly efficient vacuum-processed bulk heterojunction solar cells based on merocyanine dyes

    Energy Technology Data Exchange (ETDEWEB)

    Steinmann, Vera; Kronenberg, Nils M.; Lenze, Martin R.; Graf, Steven M.; Hertel, Dirk; Meerholz, Klaus [Department fuer Chemie, Universitaet Koeln, Luxemburger Strasse 116, 50939 Koeln (Germany); Buerckstuemmer, Hannah; Tulyakova, Elena V.; Wuerthner, Frank [Institut fuer Organische Chemie and Roentgen Research Center for Complex Material Systems, Universitaet Wuerzburg, Am Hubland, 97074 Wuerzburg (Germany)

    2011-10-15

    In order to be competitive on the energy market, organic solar cells with higher efficiency are needed. To date, polymer solar cells have retained the lead with efficiencies of up to 8%. However, research on small molecule solar cells has been catching up throughout recent years and is showing similar efficiencies, however, only for more sophisticated multilayer device configurations. In this work, a simple, highly efficient, vacuum-processed small molecule solar cell based on merocyanine dyes - traditional colorants that can easily be mass-produced and purified - is presented. In the past, merocyanines have been successfully introduced in solution-processed as well as vacuum-processed devices, demonstrating efficiencies up to 4.9%. Here, further optimization of devices is achieved while keeping the same simple layer stack, ultimately leading to efficiencies beyond the 6% mark. In addition, physical properties such as the charge carrier transport and the cell performance under various light intensities are addressed. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. [Design and study of a high resolution vacuum ultraviolet imaging spectrometer carried by satellite].

    Science.gov (United States)

    Yu, Lei; Lin, Guan-yu; Qu, Yi; Wang, Shu-rong; Wang, Long-qi

    2011-12-01

    A high resolution vacuum ultraviolet imaging spectrometer prototype carried by satellite applied to the atmosphere detection of particles distribution in 115-300 nm was developed for remote sensing. First, based on the analysis of advanced loads, the optical system including an off-axis parabolic mirror as the telescope and Czerny-Turner structure as the imaging spectrometer was chosen Secondly, the 2-D photon counting detector with MCP was adopted for the characteristic that the radiation is weak in vacuum ultraviolet waveband. Then the geometric method and 1st order differential calculation were introduced to improve the disadvantages that aberrations in the traditional structure can not be corrected homogeneously to achieve perfect broadband imaging based on the aberration theory. At last, an advanced example was designed. The simulation and calculation of results demonstrate that the modulation transfer function (MTF) of total field of view is more than 0.6 in the broadband, and the spectral resolution is 1.23 nm. The structure is convenient and predominant. It proves that the design is feasible.

  1. Vacuum interrupter, high reliability component of distribution switches, circuit breakers and contactors

    Institute of Scientific and Technical Information of China (English)

    SLADE Paul G.; LI Wang-pei; MAYO Stephen; SMITH R.Kirkland; TAYLOR Erik D.

    2007-01-01

    The use of vacuum interrupters (VIs) as the current interruption component for switches, circuit breakers, reclosers and contactors operating at distribution voltages has escalated since their introduction in the mid-1950's. This electrical product has developed a dominating position for switching and protecting distribution circuits. VIs are even being introduced into switching products operating at transmission voltages. Among the reasons for the VI's popularity are its compactness, its range of application, its low cost, its superb electrical and mechanical life and its ease of application. Its major advantage is its well-established reliability. In this paper we show how this reliability has been achieved by design, by mechanical life testing and by electrical performance testing. We introduce the "sealed for life" concept for the VI's integrity. We discuss this in terms of what is meant by a practical leak rate for VIs with a life of over 30 years. We show that a simple high voltage withstand test is an easy and effective method for monitoring the long-term vacuum integrity. Finally we evaluate the need for routine inspection of this electrical product when it is used in adverse ambient environments.

  2. Isolated Bacterial Spores at High-velocity Survive Surface Impacts in Vacuum

    Science.gov (United States)

    Austin, Daniel; Barney, Brandon

    We present experiments in which bacterial spores were found to survive being accelerated in vacuum to velocities in the range 30-120 m/s and impacted on a dense target. In these experiments, spores of Bacillus subtilis spores were charged using electrospray at atmospheric pressure, dried, and then introduced into high vacuum. Through choice of skimmers and beam tubes, different velocity ranges were achieved. An image-charge detector observed the charged spores, providing total charge and velocity. The spores then impacted a glass target within a collection vessel. After the experiment, the collection vessel contents were extracted and cultured. Several positive and negative controls were used, including the use of antibiotic-resistant spores and antibiotic-containing (rifampicin) agar for culturing. These impact velocities are of particular interest for possible transport of bacterial spores from Mars to Phobos, and may have implications for planetary protection in a Phobos sample return mission. In addition, bacteria may reach similar velocities during a spacecraft crash (e.g., within components, or from spacecraft to surface materials during impact, etc.), raising concerns about forward contamination. The velocities of interest to transport of life between planets (panspermia) are somewhat higher, but these results complement shock-based experiments and contribute to the general discussion of impact survivability of organisms.

  3. Matrix-assisted ionization vacuum for high-resolution Fourier transform ion cyclotron resonance mass spectrometers.

    Science.gov (United States)

    Wang, Beixi; Tisdale, Evgenia; Trimpin, Sarah; Wilkins, Charles L

    2014-07-15

    Matrix-assisted ionization vacuum (MAIV) produces charge states similar to electrospray ionization (ESI) from the solid state without requiring high voltage or added heat. MAIV differs from matrix-assisted laser desorption/ionization (MALDI) in that no laser is needed and abundant multiply charged ions are produced from molecules having multiple basic sites such as proteins. Here we introduce simple modifications to the commercial vacuum MALDI and ESI sources of a 9.4 T Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometer to perform MAIV from both intermediate and atmospheric pressure. The multiply charged ions are shown for the proteins bovine insulin, ubiquitin, and lysozyme using 3-nitrobenzonitrile as matrix. These are the first examples of MAIV operating at pressures as low as 10(-6) mbar in an FT-ICR mass spectrometer source, and the expected mass resolving power of 100000 to 400000 is achieved. Identical protein charge states are observed with and without laser ablation indicating minimal, if any, role of photochemical ionization for the compounds studied.

  4. Highly efficient Agrobacterium-mediated transformation of banana cv. Rasthali (AAB) via sonication and vacuum infiltration.

    Science.gov (United States)

    Subramanyam, Kondeti; Subramanyam, Koona; Sailaja, K V; Srinivasulu, M; Lakshmidevi, K

    2011-03-01

    A reproducible and efficient transformation method was developed for the banana cv. Rasthali (AAB) via Agrobacterium-mediated genetic transformation of suckers. Three-month-old banana suckers were used as explant and three Agrobacterium tumefaciens strains (EHA105, EHA101, and LBA4404) harboring the binary vector pCAMBIA1301 were used in the co-cultivation. The banana suckers were sonicated and vacuum infiltered with each of the three A. tumefaciens strains and co-cultivated in the medium containing different concentrations of acetosyringone for 3 days. The transformed shoots were selected in 30 mg/l hygromycin-containing selection medium and rooted in rooting medium containing 1 mg/l IBA and 30 mg/l hygromycin. The presence and integration of the hpt II and gus genes into the banana genome were confirmed by GUS histochemical assay, polymerase chain reaction, and southern hybridization. Among the different combinations tested, high transformation efficiency (39.4 ± 0.5% GUS positive shoots) was obtained when suckers were sonicated and vacuum infiltered for 6 min with A. tumefaciens EHA105 in presence of 50 μM acetosyringone followed by co-cultivation in 50 μM acetosyringone-containing medium for 3 days. These results suggest that an efficient Agrobacterium-mediated transformation protocol for stable integration of foreign genes into banana has been developed and that this transformation system could be useful for future studies on transferring economically important genes into banana.

  5. High-pressure (>1-bar) dielectric barrier discharge lamps generating short pulses of high-peak power vacuum ultraviolet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Carman, R J; Mildren, R P; Ward, B K; Kane, D M [Short Wavelength Interactions with Materials (SWIM), Physics Department, Macquarie University, North Ryde, Sydney, NSW 2109 (Australia)

    2004-09-07

    We have investigated the scaling of peak vacuum ultraviolet output power from homogeneous Xe dielectric barrier discharges excited by short voltage pulses. Increasing the Xe fill pressure above 1-bar provides an increased output pulse energy, a shortened pulse duration and increases in the peak output power of two to three orders of magnitude. High peak power pulses of up to 6 W cm{sup -2} are generated with a high efficiency for pulse rates up to 50 kHz. We show that the temporal pulse characteristics are in good agreement with results from detailed computer modelling of the discharge kinetics.

  6. Silicon epitaxy using tetrasilane at low temperatures in ultra-high vacuum chemical vapor deposition

    Science.gov (United States)

    Hazbun, Ramsey; Hart, John; Hickey, Ryan; Ghosh, Ayana; Fernando, Nalin; Zollner, Stefan; Adam, Thomas N.; Kolodzey, James

    2016-06-01

    The deposition of silicon using tetrasilane as a vapor precursor is described for an ultra-high vacuum chemical vapor deposition tool. The growth rates and morphology of the Si epitaxial layers over a range of temperatures and pressures are presented. The layers were characterized using transmission electron microscopy, x-ray diffraction, spectroscopic ellipsometry, Atomic Force Microscopy, and secondary ion mass spectrometry. Based on this characterization, high quality single crystal silicon epitaxy was observed. Tetrasilane was found to produce higher growth rates relative to lower order silanes, with the ability to deposit crystalline Si at low temperatures (T=400 °C), with significant amorphous growth and reactivity measured as low as 325 °C, indicating the suitability of tetrasilane for low temperature chemical vapor deposition such as for SiGeSn alloys.

  7. Search for Z′, vacuum (instability and hints of high-energy structures

    Directory of Open Access Journals (Sweden)

    Accomando Elena

    2016-01-01

    Full Text Available We study the high-energy behaviour of a class of anomaly-free abelian extensions of the Standard Model. We focus on the interplay among the phenomenological characterisation of the model and the use of precise renormalisation group methods. Using as boundary conditions regions of the parameter space at the verge of current LHC probe, interesting unification patterns emerge linked to thresholds belonging to a SO(10 grand unification theory (GUT. We stress how the evolution of the mixing between the two abelian factors may provide a valuable tool to address the candidate high-energy embedding. The emerging unification scenarios are then challenged to be perturbative and to allow for a stable vacuum.

  8. Search for $Z'$, vacuum (in)stability and hints of high-energy structures

    CERN Document Server

    Accomando, Elena; Rose, Luigi Delle; Fiaschi, Juri; Marzo, Carlo; Moretti, Stefano

    2016-01-01

    We study the high-energy behaviour of a class of anomaly-free abelian extensions of the Standard Model. We focus on the interplay among the phenomenological characterisation of the model and the use of precise renormalisation group methods. Using as boundary conditions regions of the parameter space at the verge of current LHC probe, interesting unification patterns emerge linked to thresholds belonging to a SO(10) grand unification theory (GUT). We stress how the evolution of the mixing between the two abelian factors may provide a valuable tool to address the candidate high-energy embedding. The emerging unification scenarios are then challenged to be perturbative and to allow for a stable vacuum.

  9. Ultra-high vacuum seals operating under pressure and at 1.8 K

    CERN Document Server

    Brunet, J C

    1996-01-01

    The Large Hadron Collider (LHC) project will be the next major high energy physics facility at CERN. Superconducting magnets operating at a magnetic field of 8.4 Tesla in a superfluid helium bath at 1.8 K are required to guide the high energy beams of protons on their trajectory. As part of the magnet qualification tests, magnetic measurements are made using a special device where demountable seals are required. The seals must be leak tight to vacuum and must be able to resist for short periods to pressure bursts up to 20 bar during resistive transitions (quench). Two types of seals have been qualified. Maximum leak rates were in the range 6.10-10 to 1.10-9 mbar.l.s-1, in the worst conditions (20 bar, superfluid helium at 1.8 K).

  10. Use of space ultra-vacuum for high quality semiconductor thin film growth

    Science.gov (United States)

    Ignatiev, A.; Sterling, M.; Sega, R. M.

    1992-01-01

    The utilization of space for materials processing is being expanded through a unique concept of epitaxial thin film growth in the ultra-vacuum of low earth orbit (LEO). This condition can be created in the wake of an orbiting space vehicle; and assuming that the vehicle itself does not pertub the environment, vacuum levels of better than 10 exp -14 torr can be attained. This vacuum environment has the capacity of greatly enhancing epitaxial thin film growth and will be the focus of experiments conducted aboard the Wake Shield Facility (WSF) currently being developed by the Space Vacuum Epitaxy Center (SVEC), Industry, and NASA.

  11. New perspectives in vacuum high voltage insulation. I. The transition to field emission

    CERN Document Server

    Diamond, W T

    1998-01-01

    Vacuum high-voltage insulation has been investigated for many years. Typically, electrical breakdown occurs between two broad-area electrodes at electric fields 100-1000 times lower than the breakdown field (about 5000 MV/m) between a well-prepared point cathode and a broad-area anode. Explanations of the large differences remain unsatisfactory, usually evoking field emission from small projections on the cathode that are subject to higher peak fields. The field emission then produces secondary effects that lead to breakdown. This article provides a significant resolution to this long standing problem. Field emission is not present at all fields, but typically starts after some process occurs at the cathode surface. Three effects have been identified that produce the transition to field emission: work function changes; mechanical changes produced by the strong electrical forces on the electrode surfaces; and gas desorption from the anode with sufficient density to support an avalanche discharge. Material adso...

  12. The jointing stress analysis of one-shot seal-off high-voltage vacuum interrupters

    Institute of Scientific and Technical Information of China (English)

    Zhao Zhizhong; Zou Jiyan; Cong Jiyuan; Wen Huabin; Sun Hui

    2006-01-01

    The free shrinkage of ceramic or metal is restricted due to solidification of the solder. Hence the shrinkage stress arises and the jointing strength is reduced during the brazing of high-voltage vacuum interrupters ( HVVIs ) . The solder bound contour was gained by solved energy bound equation. The finite element model of weld beads was established with Surface Evolver software. Then the stress in two different cooling techniques ( natural cooling and force cooling) was calculated with ANSYS. Comparing the stress, a better cooling technique was selected for HVVIs. Its cooling time is shortened by 3 hours while the jointing stress doesn' t increase and the tensile strength of ceramic to metal seal is not decreased. The stress-rupture tests have validated the calculated results. More important, a method is found, by which the brazing technique could be improved in advance instead of blind experiments.

  13. Fluorescence resonance energy transfer of gas-phase ions under ultra high vacuum and ambient conditions.

    Science.gov (United States)

    Frankevich, Vladimir; Chagovets, Vitaliy; Widjaja, Fanny; Barylyuk, Konstantin; Yang, Zhiyi; Zenobi, Renato

    2014-05-21

    We report evidence for fluorescence resonance energy transfer (FRET) of gas-phase ions under ultra high vacuum conditions (10(-9) mbar) inside a mass spectrometer as well as under ambient conditions inside an electrospray plume. Two different FRET pairs based on carboxyrhodamine 6G (donor) and ATTO590 or Bodipy TR (acceptor) dyes were examined and their gas-phase optical properties were studied. Our measurements indicate a different behavior for the two FRET pairs, which can be attributed to their different conformations in the gas phase. Upon desolvation via electrospray ionization, one of the FRET pairs undergoes a conformational change that leads to disappearance of FRET. This study shows the promise of FRET to obtain a direct correlation between solution and gas-phase structures.

  14. Influence of rapid thermal vacuum annealing and high temperature treatment on the properties of PSG films

    Energy Technology Data Exchange (ETDEWEB)

    Beschkov, G [Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Science, 72 Tsarigradsko Chaussee, 1784 Sofia (Bulgaria); Bakardjieva, V; Alexieva, Z [Central Laboratory of Solar Energy and New Energy Sources, Bulgarian Academy of Science, 72 Tsarigradsko Chaussee, 1784 Sofia (Bulgaria)], E-mail: vlabakar@phys.bas.bg

    2008-05-01

    The effect is presented of rapid thermal annealing (RTA) in vacuum and thermal annealing in water vapor at 850 deg. C on the properties of phosphosilicate glass (PSG) films deposited in PECVD and {mu}PCVD reactors. The films were characterized by etch rates and XPS and AES analyses. The RTA was carried out at 800 - 1400 deg. C at annealing times varying from 15 to 180 sec. The RTA caused a significant decrease in the etch rate, which is indicative of structural changes. The XPS and AES analyses showed that the PECVD PSG films contain excess Si due to the lower oxidation activity of N{sub 2}O. The excess Si can be oxidized in water vapor at high temperatures. The excess Si leads to a decrease in the etching rate of the PECVD PSG layers as compared to that of the {mu}PCVD films.

  15. Influence of rapid thermal vacuum annealing and high temperature treatment on the properties of PSG films

    Science.gov (United States)

    Beschkov, G.; Bakardjieva, V.; Alexieva, Z.

    2008-05-01

    The effect is presented of rapid thermal annealing (RTA) in vacuum and thermal annealing in water vapor at 850 °C on the properties of phosphosilicate glass (PSG) films deposited in PECVD and μPCVD reactors. The films were characterized by etch rates and XPS and AES analyses. The RTA was carried out at 800 - 1400 °C at annealing times varying from 15 to 180 sec. The RTA caused a significant decrease in the etch rate, which is indicative of structural changes. The XPS and AES analyses showed that the PECVD PSG films contain excess Si due to the lower oxidation activity of N2O. The excess Si can be oxidized in water vapor at high temperatures. The excess Si leads to a decrease in the etching rate of the PECVD PSG layers as compared to that of the μPCVD films.

  16. Highly reflective and adhesive surface of aluminized polyvinyl chloride film by vacuum evaporation

    Science.gov (United States)

    Li, Denian; Tai, Qile; Feng, Qiang; Li, Qi; Xu, Xizhe; Li, Hairong; Huang, Jing; Dong, Lijie; Xie, Haian; Xiong, Chuanxi

    2014-08-01

    Aluminized poly(vinyl chloride) (PVC) film with high reflectivity and strong adhesion was facilely fabricated by vacuum evaporation. The technical study revealed that both alkali-pretreatment of the PVC matrix and thermal annealing after aluminization could greatly promote the peeling adhesion force of this metal/polymer composite by producing interfacial active chemical groups and removing the inner stress, respectively. Reflectivity test and AFM study indicated that the reflecting capacitance of the aluminum coating was closely related to the surface roughness, which can be easily controlled by modulating deposition of aluminum. Moreover, the formation of aluminum layer follows an island model process, and a continuous and smooth coating with highest reflectivity and lowest surface resistance was achieved at deposition time of 60 s. We anticipate that the cost-effective metallized PVC film by this strategy may find extensive applications in light harvesting, solar energy, and flexible mirrors, among others.

  17. Nano-materials for adhesive-free adsorbers for bakable extreme high vacuum cryopump surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Stutzman, Marcy; Jordan, Kevin; Whitney, Roy R.

    2016-10-11

    A cryosorber panel having nanomaterials used for the cryosorption material, with nanomaterial either grown directly on the cryopanel or freestanding nanomaterials attached to the cryopanel mechanically without the use of adhesives. Such nanomaterial cryosorber materials can be used in place of conventional charcoals that are attached to cryosorber panels with special low outgassing, low temperature capable adhesives. Carbon nanotubes and other nanomaterials could serve the same purpose as conventional charcoal cryosorbers, providing a large surface area for cryosorption without the need for adhesive since the nanomaterials can be grown directly on a metallic substrate or mechanically attached. The nanomaterials would be capable of being fully baked by heating above 100.degree. C., thereby eliminating water vapor from the system, eliminating adhesives from the system, and allowing a full bake of the system to reduce hydrogen outgassing, with the goal of obtaining extreme high vacuum where the pump can produce pressures below 1.times.10.sup.-12 Torr.

  18. Vacuum ultraviolet argon excimer laser at 126 nm excited by a high intensity laser

    Science.gov (United States)

    Kaku, Masanori; Harano, Shinya; Katto, Masahito; Kubodera, Shoichi

    2010-09-01

    We have observed the optical amplification of the Ar2* excimer at 126 nm pumped by optical-field-induced ionization (OFI) caused by an infrared high-intensity laser. We have evaluated similar small signal gain coefficients of approximately 1.0 cm-1 in two different experiments, where OFI Ar plasmas as gain media were produced in free space filled with Ar and inside an Ar-filled hollow fiber. This indicates that the function of a hollow fiber was to guide the infrared excitation laser and VUV Ar2* emissions, and not to regulate the OFI plasma. Despite the gain coefficient value at 126 nm, the laser oscillation has not been observed. This was limited by the optical quality of available state-of-the-art vacuum ultraviolet optics.

  19. A vacuum sealed high emission current and transmission efficiency carbon nanotube triode

    Directory of Open Access Journals (Sweden)

    Yunsong Di

    2016-04-01

    Full Text Available A vacuum sealed carbon nanotubes (CNTs triode with a concave and spoke-shaped Mo grid is presented. Due to the high aperture ratio of the grid, the emission current could be modulated at a relatively high electric field. Totally 75mA emission current has been obtained from the CNTs cathode with the average applied field by the grid shifting from 8 to 13 V/μm. Whilst with the electron transmission efficiency of the grid over 56%, a remarkable high modulated current electron beam over 42mA has been collected by the anode. Also contributed by the high aperture ration of the grid, desorbed gas molecules could flow away from the emission area rapidly when the triode has been operated at a relative high emission current, and finally collected by a vacion pump. The working pressure has been maintained at ∼1 × 10−7 Torr, seldom spark phenomena occurred. Nearly perfect I-V curve and corresponding Fowler-Nordheim (FN plot confirmed the accuracy of the measured data, and the emission current was long term stable and reproducible. Thusly, this kind of triode would be used as a high-power electron source.

  20. A vacuum sealed high emission current and transmission efficiency carbon nanotube triode

    Science.gov (United States)

    Di, Yunsong; Wang, Qilong; Zhang, Xiaobing; Lei, Wei; Du, Xiaofei; Yu, Cairu

    2016-04-01

    A vacuum sealed carbon nanotubes (CNTs) triode with a concave and spoke-shaped Mo grid is presented. Due to the high aperture ratio of the grid, the emission current could be modulated at a relatively high electric field. Totally 75mA emission current has been obtained from the CNTs cathode with the average applied field by the grid shifting from 8 to 13 V/μm. Whilst with the electron transmission efficiency of the grid over 56%, a remarkable high modulated current electron beam over 42mA has been collected by the anode. Also contributed by the high aperture ration of the grid, desorbed gas molecules could flow away from the emission area rapidly when the triode has been operated at a relative high emission current, and finally collected by a vacion pump. The working pressure has been maintained at ˜1 × 10-7 Torr, seldom spark phenomena occurred. Nearly perfect I-V curve and corresponding Fowler-Nordheim (FN) plot confirmed the accuracy of the measured data, and the emission current was long term stable and reproducible. Thusly, this kind of triode would be used as a high-power electron source.

  1. A vacuum sealed high emission current and transmission efficiency carbon nanotube triode

    Energy Technology Data Exchange (ETDEWEB)

    Di, Yunsong [School of Electronic Science & Engineering, Southeast University, Nanjing 210096 (China); Jiangsu Key Laboratory of Optoelectronic Technology, Nanjing Normal University, Nanjing 210023 (China); Wang, Qilong; Zhang, Xiaobing, E-mail: bell@seu.edu.cn; Lei, Wei; Du, Xiaofei; Yu, Cairu [School of Electronic Science & Engineering, Southeast University, Nanjing 210096 (China)

    2016-04-15

    A vacuum sealed carbon nanotubes (CNTs) triode with a concave and spoke-shaped Mo grid is presented. Due to the high aperture ratio of the grid, the emission current could be modulated at a relatively high electric field. Totally 75 mA emission current has been obtained from the CNTs cathode with the average applied field by the grid shifting from 8 to 13 V/μm. Whilst with the electron transmission efficiency of the grid over 56%, a remarkable high modulated current electron beam over 42 mA has been collected by the anode. Also contributed by the high aperture ration of the grid, desorbed gas molecules could flow away from the emission area rapidly when the triode has been operated at a relative high emission current, and finally collected by a vacion pump. The working pressure has been maintained at ∼1 × 10{sup −7} Torr, seldom spark phenomena occurred. Nearly perfect I-V curve and corresponding Fowler-Nordheim (FN) plot confirmed the accuracy of the measured data, and the emission current was long term stable and reproducible. Thusly, this kind of triode would be used as a high-power electron source.

  2. High power spectrometer for the characterization of photovoltaic cells in a controlled atmosphere or vacuum

    DEFF Research Database (Denmark)

    Krebs, Frederik C; Jørgensen, M.

    2003-01-01

    single monochromator grating. The photovoltaic sample under test is placed in a stainless-steel vacuum chamber allowing for operating pressures down to 10(-6) mbar equipped with a quartz window and electrical connections. The entire vacuum chamber was placed on a moving arm allowing for positioning...

  3. Design and installation of a low particulate, ultrahigh vacuum system for a high power free-electron laser

    CERN Document Server

    Dyll, Aa; Feldl, E; Parkinson, J; Preble, J; Siggins, T; Williams, S; Wisema, M

    1999-01-01

    A high-average power (kW) infrared (IR) free-electron laser (FEL) is currently being commissioned for the Jefferson Laboratory FEL User Facility. The IR FEL is driven by a unique superconducting rf linac which is recirculated to recover electron beam power that is not radiated in the FEL. The design and installation of the vacuum system for the FEL involved particular attention to minimizing particulate contamination which could cause problems with the superconducting acceleration cavities and the high power FEL optics. Particulate contamination levels of all vacuum components were monitored during the cleaning process using laser scattering. Cleaning, transport, and installation procedures were developed to minimize the contamination of the complete system. We will summarize a data base we compiled of particulate contamination levels of the various components installed in the FEL vacuum system.

  4. Development of High Performance Composite Foam Insulation with Vacuum Insulation Cores

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Kaushik [ORNL; Desjarlais, Andre Omer [ORNL; SmithPhD, Douglas [NanoPore, Inc.; LettsPhD, John [Firestone Building Products; YaoPhD, Jennifer [Firestone Building Products

    2016-01-01

    Development of a high performance thermal insulation (thermal resistance or R-value per inch of R-12 hr-ft2- F/Btu-in or greater), with twice the thermal resistance of state-of-the-art commercial insulation materials ( R6/inch for foam insulation), promises a transformational impact in the area of building insulation. In 2010, in the US, the building envelope-related primary energy consumption was 15.6 quads, of which 5.75 quads were due to opaque wall and roof sections; the total US consumption (building, industrial and transportation) was 98 quads. In other words, the wall and roof contribution was almost 6% of the entire US primary energy consumption. Building energy modeling analyses have shown that adding insulation to increase the R-value of the external walls of residential buildings by R10-20 (hr-ft2- F/Btu) can yield savings of 38-50% in wall-generated heating and cooling loads. Adding R20 will require substantial thicknesses of current commercial insulation materials, often requiring significant (and sometimes cost-prohibitive) alterations to existing buildings. This article describes the development of a next-generation composite insulation with a target thermal resistance of R25 for a 2 inch thick board (R12/inch or higher). The composite insulation will contain vacuum insulation cores, which are nominally R35-40/inch, encapsulated in polyisocyanurate foam. A recently-developed variant of vacuum insulation, called modified atmosphere insulation (MAI), was used in this research. Some background information on the thermal performance and distinguishing features of MAI has been provided. Technical details of the composite insulation development and manufacturing as well as laboratory evaluation of prototype insulation boards are presented.

  5. Flash flow pyrolysis: mimicking flash vacuum pyrolysis in a high-temperature/high-pressure liquid-phase microreactor environment.

    Science.gov (United States)

    Cantillo, David; Sheibani, Hassan; Kappe, C Oliver

    2012-03-02

    Flash vacuum pyrolysis (FVP) is a gas-phase continuous-flow technique where a substrate is sublimed through a hot quartz tube under high vacuum at temperatures of 400-1100 °C. Thermal activation occurs mainly by molecule-wall collisions with contact times in the region of milliseconds. As a preparative method, FVP is used mainly to induce intramolecular high-temperature transformations leading to products that cannot easily be obtained by other methods. It is demonstrated herein that liquid-phase high-temperature/high-pressure (high-T/p) microreactor conditions (160-350 °C, 90-180 bar) employing near- or supercritical fluids as reaction media can mimic the results obtained using preparative gas-phase FVP protocols. The high-T/p liquid-phase "flash flow pyrolysis" (FFP) technique was applied to the thermolysis of Meldrum's acid derivatives, pyrrole-2,3-diones, and pyrrole-2-carboxylic esters, producing the expected target heterocycles in high yields with residence times between 10 s and 10 min. The exact control over flow rate (and thus residence time) using the liquid-phase FFP method allows a tuning of reaction selectivities not easily achievable using FVP. Since the solution-phase FFP method does not require the substrate to be volatile any more--a major limitation in classical FVP--the transformations become readily scalable, allowing higher productivities and space-time yields compared with gas-phase protocols. Differential scanning calorimetry measurements and extensive DFT calculations provided essential information on pyrolysis energy barriers and the involved reaction mechanisms. A correlation between computed activation energies and experimental gas-phase FVP (molecule-wall collisions) and liquid-phase FFP (molecule-molecule collisions) pyrolysis temperatures was derived.

  6. Growth control of oxygen stoichiometry in homoepitaxial SrTiO3 films by pulsed laser epitaxy in high vacuum.

    Science.gov (United States)

    Lee, Ho Nyung; Ambrose Seo, Sung S; Choi, Woo Seok; Rouleau, Christopher M

    2016-01-29

    In many transition metal oxides, oxygen stoichiometry is one of the most critical parameters that plays a key role in determining the structural, physical, optical, and electrochemical properties of the material. However, controlling the growth to obtain high quality single crystal films having the right oxygen stoichiometry, especially in a high vacuum environment, has been viewed as a challenge. In this work, we show that, through proper control of the plume kinetic energy, stoichiometric crystalline films can be synthesized without generating oxygen defects even in high vacuum. We use a model homoepitaxial system of SrTiO3 (STO) thin films on single crystal STO substrates. Physical property measurements indicate that oxygen vacancy generation in high vacuum is strongly influenced by the energetics of the laser plume, and it can be controlled by proper laser beam delivery. Therefore, our finding not only provides essential insight into oxygen stoichiometry control in high vacuum for understanding the fundamental properties of STO-based thin films and heterostructures, but expands the utility of pulsed laser epitaxy of other materials as well.

  7. Probe characterization of high-current driven metal plasma in a vacuum-arc rail gun

    Science.gov (United States)

    Vijayan, T.; Roychowdhury, P.; Venkatramani, N.

    2004-10-01

    The characteristics of metal plasma launched by high-current electric arc in a vacuum-arc rail gun are determined by employing electrical and magnetic probes. These measurements are validated by results from theoretical simulations. The arc coupled nonlinear circuit equations are solved simultaneously with the Newtonian arc motion and revealed the undercritically damped behavior of the arc current identical to the arc-current signal recorded by the Rogowski magnetic probe. Similarly the arc velocity and displacement derived from the signatures of B-dot probes are shown to concur closely with the results of J ×B propulsion from simulation. The heating of plasma is formulated in a three-electron population regime with direct arc energy coupling through magnetohydrodynamic, ion-acoustic, Coulomb, and neutral interactions. This results in high temperature (Te) of hundreds of eV in the arc as revealed by the simulation. Hence Te of the rapidly cooling and equilibrating plasma that emerged from the muzzle is high around 80-90eV, which is confirmed by Langmuir electric probe measurements. Density ne of this metal plasma is shown to be in the range 4×1021-6×1021m-3 and includes multiple ion charge states. The exit velocity of the plasma measured by a pair of Langmuir probes is close to 2.2×106cm/s and matched well with the arc velocity determined by the B-dot probes and the results from simulation.

  8. Direct electroplating of copper on tantalum from ionic liquids in high vacuum: origin of the tantalum oxide layer.

    Science.gov (United States)

    Schaltin, Stijn; D'Urzo, Lucia; Zhao, Qiang; Vantomme, André; Plank, Harald; Kothleitner, Gerald; Gspan, Christian; Binnemans, Koen; Fransaer, Jan

    2012-10-21

    In this paper, it is shown that high vacuum conditions are not sufficient to completely remove water and oxygen from the ionic liquid 1-ethyl-3-methylimidazolium chloride. Complete removal of water demands heating above 150 °C under reduced pressure, as proven by Nuclear Reaction Analysis (NRA). Dissolved oxygen gas can only be removed by the use of an oxygen scavenger such as hydroquinone, despite the fact that calculations show that oxygen should be removed completely by the applied vacuum conditions. After applying a strict drying procedure and scavenging of molecular oxygen, it was possible to deposit copper directly on tantalum without the presence of an intervening oxide layer.

  9. Systematic study of the dolomite (104) surface by bimodal dynamic force microscopy in ultra-high vacuum.

    Science.gov (United States)

    Kawai, Shigeki; Pina, Carlos M; Bubendorf, Alexander; Fessler, Gregor; Glatzel, Thilo; Gnecco, Enrico; Meyer, Ernst

    2013-02-08

    We have investigated the morphology and structure of dolomite MgCa(CO(3))(2)(104) surfaces by bimodal dynamic force microscopy with flexural and torsional resonance modes in ultra-high vacuum at room temperature. We found that the surface slowly decomposes by degassing CO(2) in a vacuum and becomes covered by amorphous clusters, presumably MgO and CaO. By choosing an optimal sample preparation procedure (i.e. cleaving in a vacuum and mild annealing for stabilizing clusters for a short time), atomically clean surfaces were obtained. The complex tip-sample interaction, arising from carbonate groups and Mg and Ca atoms of the surface, induces a large variety of atomic-scale imaging features.

  10. High-speed organic photo-detectors fabricated by vacuum and solution processes and application for optical transmission

    Science.gov (United States)

    Ohmori, Yutaka; Hamasaki, Tatsunari; Morimune, Taichiro; Kajii, Hirotake

    2008-04-01

    Organic photo-detectors (OPDs) have been discussed as high-speed photo-detectors fabricated by vacuum and solution processes. By vacuum process, OPD was fabricated on an ITO-coated glass substrate by organic molecular beam deposition (OMBD). Copper phthalocyanine (CuPc) and N,N'-bis(2,5-di-tert-butylphenyl) 3,4,9,10-perylene dicarboximide (BPPC) were used as a p-type and an n-type material. The photo response of OPD was evaluated using a laser (λ=650 nm) and clear response signals at 100 MHz were observed. The imaging signals were successfully received using the OPDs. For solution processed OPDs, poly(9,9-dioctylfluorene) and a phosphorescent iridium derivative were used as a host and a dopant material, respectively. A pulsed signal of 100MHz and amore than 40 MHz were observed by the OPDs fabricated by the vacuum processed and the solution processed devices, respectively.

  11. High-resolution vacuum-ultraviolet photoabsorption spectra of 1-butyne and 2-butyne

    Energy Technology Data Exchange (ETDEWEB)

    Jacovella, U. [Laboratorium für Physikalische Chemie, ETH Zürich, 8093 Zürich (Switzerland); Holland, D. M. P. [STFC, Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD (United Kingdom); Boyé-Péronne, S.; Gans, B. [Institut des Sciences Moléculaires d’Orsay, UMR 8214, CNRS and Université Paris-Sud, F-91405 Orsay (France); Oliveira, N. de; Joyeux, D.; Archer, L. E. [Synchrotron Soleil, L’Orme des Merisiers, F-91192 Gif-sur-Yvette (France); Lucchese, R. R. [Department of Chemistry, Texas A& M University, College Station, Texas 77843 (United States); Xu, H.; Pratt, S. T. [Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2015-07-21

    The absolute photoabsorption cross sections of 1- and 2-butyne have been recorded at high resolution by using the vacuum-ultraviolet Fourier-Transform spectrometer at the SOLEIL Synchrotron. Both spectra show more resolved structure than previously observed, especially in the case of 2-butyne. In this work, we assess the potential importance of Rydberg states with higher values of orbital angular momentum, l, than are typically observed in photoabsorption experiments from ground state molecules. We show how the character of the highest occupied molecular orbitals in 1- and 2-butyne suggests the potential importance of transitions to such high-l (l = 3 and 4) Rydberg states. Furthermore, we use theoretical calculations of the partial wave composition of the absorption cross section just above the ionization threshold and the principle of continuity of oscillator strength through an ionization threshold to support this conclusion. The new absolute photoabsorption cross sections are discussed in light of these arguments, and the results are consistent with the expectations. This type of argument should be valuable for assessing the potential importance of different Rydberg series when sufficiently accurate direct quantum chemical calculations are difficult, for example, in the n ≥ 5 manifolds of excited states of larger molecules.

  12. High-performance parallel image reconstruction for the New Vacuum Solar Telescope

    Science.gov (United States)

    Li, Xue-Bao; Liu, Zhong; Wang, Feng; Jin, Zhen-Yu; Xiang, Yong-Yuan; Zheng, Yan-Fang

    2015-06-01

    Many technologies have been developed to help improve spatial resolution of observational images for ground-based solar telescopes, such as adaptive optics (AO) systems and post-processing reconstruction. As any AO system correction is only partial, it is indispensable to use post-processing reconstruction techniques. In the New Vacuum Solar Telescope (NVST), a speckle-masking method is used to achieve the diffraction-limited resolution of the telescope. Although the method is very promising, the computation is quite intensive, and the amount of data is tremendous, requiring several months to reconstruct observational data of one day on a high-end computer. To accelerate image reconstruction, we parallelize the program package on a high-performance cluster. We describe parallel implementation details for several reconstruction procedures. The code is written in the C language using the Message Passing Interface (MPI) and is optimized for parallel processing in a multiprocessor environment. We show the excellent performance of parallel implementation, and the whole data processing speed is about 71 times faster than before. Finally, we analyze the scalability of the code to find possible bottlenecks, and propose several ways to further improve the parallel performance. We conclude that the presented program is capable of executing reconstruction applications in real-time at NVST.

  13. Unintentional carbide formation evidenced during high-vacuum magnetron sputtering of transition metal nitride thin films

    Science.gov (United States)

    Greczynski, G.; Mráz, S.; Hultman, L.; Schneider, J. M.

    2016-11-01

    Carbide signatures are ubiquitous in the surface analyses of industrially sputter-deposited transition metal nitride thin films grown with carbon-less source materials in typical high-vacuum systems. We use high-energy-resolution photoelectron spectroscopy to reveal details of carbon temporal chemical state evolution, from carbide formed during film growth to adventitious carbon adsorbed upon contact with air. Using in-situ grown Al capping layers that protect the as-deposited transition metal nitride surfaces from oxidation, it is shown that the carbide forms during film growth rather than as a result of post deposition atmosphere exposure. The XPS signature of carbides is masked by the presence of adventitious carbon contamination, appearing as soon as samples are exposed to atmosphere, and eventually disappears after one week-long storage in lab atmosphere. The concentration of carbon assigned to carbide species varies from 0.28 at% for ZrN sample, to 0.25 and 0.11 at% for TiN and HfN, respectively. These findings are relevant for numerous applications, as unintentionally formed impurity phases may dramatically alter catalytic activity, charge transport and mechanical properties by offsetting the onset of thermally-induced phase transitions. Therefore, the chemical state of C impurities in PVD-grown films should be carefully investigated.

  14. Concept for support and heating of plate-like samples in the ultra-high vacuum

    Science.gov (United States)

    Tröger, L.; Pieper, H. H.; Reichling, M.

    2013-01-01

    We present the concept for a sample holder designed for mounting and heating of plate-like samples that is based on a clamping mechanism for easy handling. The clamping mechanism consists of a U-shaped bracket encompassing the sample support plate from the rear. Two spring wires are fixed in the walls of the bracket spanning the sample to secure it with only two point contacts. This enables the sample to freely expand or contract during heating and cooling. To accommodate for a large variety in sample size, shape, and quality, we introduce two designs differing in the generation of the clamping force: One pressing the sample against the spring wires, the other one pulling the spring wires onto the sample. Both designs yield an automatically even alignment of the sample during the mounting process to achieve an even load distribution and reliable fixation specifically for brittle samples. For high temperature treatment, the sample holders are enhanced by a resistive heating plate. As only the sample and a small fraction of the sample holder are heated, temperatures of 1300 °C are reached with only 8 W heating power. The sample support and heating components are mounted on a 11 mm × 13 mm base plate with a handle that can be transferred between the sample entry stage, the preparation stage, and surface science experiments in the ultra-high vacuum system.

  15. Non vacuum electron beam welding of zinc coated high-strength steels

    Energy Technology Data Exchange (ETDEWEB)

    Bach, F.W.; Beniyash, A.; Lau, K.; Versemann, R. [Hannover Univ. (Germany). Inst. of Materials Science

    2005-07-01

    Due to the requirement of conservation of nature and natural resources, today more and more high-strength steels are applied for modern concepts of lightweight construction in auto body manufacturing. For a better corrosion protection mainly hot-dip galvanized sheets or electrolytically coated sheets are used. Non Vacuum Electron Beam Welding (NVEBW) offers several technological and economical advantages for joining zinc coated sheets, which are presented in this paper. The results are based on extensive welding investigations that were performed with the 175 kV-NVEBW machine at Institute of Materials Science, University of Hanover. Different zinc coated steels (microalloyed steel, dualphase steel, residualaustenite steel, complexphase steel, martensitic steel) with sheet thicknesses between 0.8-2.0 mm were welded. A main focus of the work is to investigate the influence of the zinc coating on the welding behaviour at different seam geometries (butt joint, edge-raised seam, lap joint, fillet weld, tailored blank). Up to welding speeds of 10 m/min welds with good properties were obtained. In some cases (lap joints, edge raised seams) it is necessary to weld with a weld gap for zinc evaporation. But it turned out that NVEBW has a wide tolerance concerning the gap width. Furthermore, the presentation shows the results of extensive mechanical tests to NVEBW-welded high-strength steels, especially to hardness tests, tensile tests and forming investigations. (orig.)

  16. High-accuracy measurement of the emission spectrum of liquid xenon in the vacuum ultraviolet region

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Keiko, E-mail: fujii-keiko-nv@ynu.jp [Faculty of Engineering, Yokohama National University, Yokohama, Kanagawa 240-8501 (Japan); Endo, Yuya; Torigoe, Yui; Nakamura, Shogo [Faculty of Engineering, Yokohama National University, Yokohama, Kanagawa 240-8501 (Japan); Haruyama, Tomiyoshi; Kasami, Katsuyu [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan); Mihara, Satoshi; Saito, Kiwamu; Sasaki, Shinichi [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan); The Graduate School of Advanced Studies, Hayama, Kanagawa 240-0193 (Japan); Tawara, Hiroko [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan)

    2015-09-21

    The emission spectrum of cryogenic liquid xenon in the vacuum ultraviolet region was measured by irradiating liquid xenon with gamma-rays from a radioactive source. To achieve a high signal-to-noise ratio, we employed coincident photon counting. Additionally, the charge of the photo-sensor signals was measured to estimate the number of detected photons accurately. In addition, proper corrections were incorporated for the wavelength; response functions of the apparatus obtained using a low-pressure mercury lamp, and photon detection efficiencies of the optical system were considered. The obtained emission spectrum is found to be in the shape of a Gaussian function, with the center at 57,199±34 (stat.)±33 (syst.) cm{sup −1} (174.8±0.1 (stat.)±0.1 (syst.) nm) and the full width at half maximum of 3328±72 (stat.)±65 (syst.) cm{sup −1} (10.2±0.2 (stat.)±0.2 (sys.) nm). These results are the most accurate values obtained in terms of the data acquisition method and the calibration for the experimental system and provide valuable information regarding the high-precision instruments that employ a liquid-xenon scintillator.

  17. Calibrating System for Vacuum Gauges

    Institute of Scientific and Technical Information of China (English)

    MengJun; YangXiaotian; HaoBinggan; HouShengjun; HuZhenjun

    2003-01-01

    In order to measure the vacuum degree, a lot of vacuum gauges will be used in CSR vacuum system. We bought several types of vacuum gauges. We know that different typos of vacuum gauges or even one type of vacuum gauges have different measure results in same condition, so they must be calibrated. But it seems impossible for us to send so many gauges to the calibrating station outside because of the high price. So the best choice is to build a second class calibrating station for vacuum gauges by ourselves (Fig.l).

  18. Study of the suitability of 3D printing for Ultra-High Vacuum applications

    Science.gov (United States)

    Jenzer, Stéphane; Alves, Manuel; Delerue, Nicolas; Gonnin, Alexandre; Grasset, Denis; Letellier-Cohen, Frederic; Mercier, Bruno; Mistretta, Eric; Prevost, Christophe; Vion, Alexis; Wilmes, Jean-Pierre

    2017-07-01

    In the recent year additive manufacturing (3D printing) has revolutionized mechanical engineering by allowing the quick production of mechanical components with complex shapes. So far most of these components are made in plastic and therefore can not be used in accelerator beam pipes. We have investigated samples printed using a metal 3D printer to study their behavior under vacuum. We report on our first tests showing that such samples are vacuum compatible and comparing pumping time.

  19. The development of an atom chip with through silicon vias for an ultra-high-vacuum cell

    Science.gov (United States)

    Chuang, Ho-Chiao; Li, Hsiang-Fu; Lin, Yun-Siang; Lin, Yu-Hsin; Huang, Chi-Sheng

    2013-08-01

    This paper describes the development, fabrication and examination of an atom chip through silicon vias (TSV), which is anodically bonded with a Pyrex glass cell to form an ultra-high-vacuum system for the application of Bose-Einstein condensation (BEC) experiments. The silicon via is etched by the inductively coupled plasma reactive ion etch and filled by copper plating technology. The metal wires on both sides of the atom chips are patterned by the lithography process. Three different sizes of TSV are made and tested by continuously applying a maximum current of 17 A under the vacuum (70 Torr) and in air. In addition, after the thermal cycling of an anodic bonding process (requested at 350 °C) and a high electric field of 1000 V m-1, the TSV on atom chips can still hold the ultra-high vacuum (UHV). The conductive and vacuum yields of the TSV improved from 50% to 100% and from 75% to 81.25%, respectively after the modification of the fabrication process. Finally, the UHV test of TSV on atom chips at room temperature can be reached at 8 × 10-10 Torr, thus satisfying the requirements of atomic physics experiments under the UHV environment.

  20. Development of Subischial Prosthetic Sockets with Vacuum-Assisted Suspension for Highly Active Persons with Transfemoral Amputations

    Science.gov (United States)

    2016-12-01

    with flexible check socket. 488 Figure 6 Still frame from one of the split- screen videos used to visually assess gait in both 489 sockets during the...Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT The purpose of this project was to develop a highly flexible sub-ischial prosthetic socket with assisted...vacuum suspension for highly active persons with transfemoral amputation. The Specific Aims were to: A1. Develop a highly flexible socket with sub

  1. High-Quality ZrO2 Thin Films Deposited on Silicon by High Vacuum Electron Beam Evaporation

    Institute of Scientific and Technical Information of China (English)

    章宁琳; 万青; 宋志棠; 沈勤我; 祝向荣; 林成鲁

    2002-01-01

    Zirconium oxide films were deposited on p-type Si(l00) substrates using high vacuum electron beam evaporation (HVEBE) at room temperature. X-ray photoelectric spectroscopy shows that the dominant chemical state of zirconia thin films is in the fully oxidized state of Zr4+, no matter whether annealed in oxygen. The structural information from x-ray diffraction shows that zirconia thin films deposited at room temperature by HVEBEwere completely amorphous before and after the annealing. The spreading resistance profile indicates that ZrO2 thin films have excellent insulation property (with a resistance of more than 10s Ω) and the thickness is 800A.After thermal treatment at 600°C in O2 ambient, the root-mean-square roughness changed from 8.09 A of the as-deposited film to 13.8A across an area of i × 1μm2.

  2. Magnetic Flashover Inhibition Testing of High Power Vacuum-Insulator Interfaces

    Science.gov (United States)

    Benwell, Andrew; Kovaleski, Scott; Gahl, John

    2004-11-01

    University of Missouri Terawatt Test Stand, Department of Electrical and Computer Engineering, University of Missouri Â- Columbia, Columbia, MO. Flashover occurring at vacuum-insulator interfaces is a common problem in the design of high power pulsed power machines. Avalanche breakdown might be prevented on the insulator surface by taking advantage of the E × B force to bend the path of electrons away from the insulator. Magnetic flashover inhibition (MFI) has been demonstrated [1]; however particular breakdown conditions such as the ratio of E/B are not well known. An inductive load to test the conditions under which MFI occurs is being designed for the MU Terrawatt Test Stand (MUTTS). The test stand can provide a 150 ns pulse at 2.7MV and 400kA peak and can accommodate an adjustable design load. Details of the load design will be presented as well as theoretical analysis of the experimental circuit and of the physics of magnetic flashover insulation. [1] J.P. VanDevender, D.H. McDaniel, E.L. Neau, R.E. Mattis, K.D. Bergeron, "Magnetic Inhibition of Insulator Flashover", Journal of Applied Physics 53(6), June 1982

  3. High Power Proton Accelerator Development at KAERI and its Vacuum System

    Science.gov (United States)

    Choi, Byung-Ho; Park, Mi Young; Kim, Kui Young; Kim, Kye Ryung; Kim, Jun Yeon; Cho, Yong-Sub

    The Proton Engineering Frontier Project (PEFP), approved and launched by the Korean government in July 2002, includes a 100 MeV proton linear accelerator (linac) development and programs for its utilization and application. The main goals in the first phase of the project, spanning from 2002 to 2005, were the design of a 100 MeV proton linac and the development of a 20 MeV linac consisting of a 50 keV proton injector, a 3 MeV radio frequency quadrupole (RFQ), and a 20 MeV drift tube linac (DTL). The 50 keV injector and 3 MeV RFQ have been installed and tested, and the 20 MeV DTL is being assembled, tuned and under a beam test. At the same time, the utilization programs using the proton beam have been planned, and some are now under way. The vacuum system of the 20 MeV proton linac and its related issues, especially in operation with a high duty, are discussed in detail.

  4. Lipid and protein oxidation and sensory properties of vacuum-packaged dry-cured ham subjected to high hydrostatic pressure.

    Science.gov (United States)

    Fuentes, Verónica; Ventanas, Jesús; Morcuende, David; Estévez, Mario; Ventanas, Sonia

    2010-07-01

    The effect of HHP treatment (600 MPa) on the oxidative stability of lipids and proteins of vacuum-packaged Iberian dry-cured ham and the impact on the sensory characteristics of the product was investigated. In order to assess how different commercial presentations are affected by HHP treatment, three different presentations of vacuum-packaged Iberian dry-cured ham were considered, namely, (i) intact format (IF) corresponding to non-sliced vacuum-packaged dry-cured ham, (ii) conventional-sliced format (CSF) corresponding to dry-cured ham slices placed stretched out in the package and (iii) alternative-sliced format (ASF) corresponding to dry-cured ham slices piled up horizontally. The oxidation of dry-cured ham lipids and proteins was enhanced by HHP-treatment with the presentation being highly influential on these oxidative reactions. Pre-slicing dry-cured ham results in a more susceptible product to oxidative reactions during pressurisation and subsequent refrigerated storage. Possible mechanisms, by which HHP-induced oxidative reactions would affect particular sensory traits in vacuum-packaged Iberian dry-cured ham such as colour, texture and flavour attributes, are discussed.

  5. Recent study of nanomaterials prepared by inert gas condensation using ultra high vacuum chamber

    Indian Academy of Sciences (India)

    S Ramasamy; D J Smith; P Thangadurai; K Ravichandran; T Prakash; K Padmaprasad; V Sabarinathan

    2005-11-01

    The ultra high vacuum chamber was developed in the Department of Nuclear Physics, University of Madras with the funding from DST, India. This UHV chamber is used to prepare nanocrystalline materials by inert gas condensation technique (IGCT). Nanocrystalline materials such as PbF2, Mn2+-doped PbF2, Sn-doped In2O3 (ITO), ZnO, Al2O3, Ag2O, CdO, CuO, ZnSe:ZnO etc., were prepared by this technique and characterized. Results of some of these materials will be presented in this paper. In solid-state 207Pb NMR on PbF2 a separate signal due to the presence of grain boundary has been observed. The structural phase transition pressure during the phase transformation from the cubic phase to orthorhombic phase under high pressure shows an increase with the decrease in grain size. Presence of electronic centres in nanocrystalline PbF2 is observed from Raman studies and the same has been confirmed by photoluminescence studies. Al2O3 was prepared and 56Fe ions were implanted. After implantation segregation of 56Fe ions was examined by SEM. The oxidation properties of ITO were studied by HRTEM. As against the expectation of oxide coating on individual nanograins of In{Sn alloy, ITO nanograins grew into faceted nanograins on heat treatment in air and O2 atmosphere. The growth of ITO under O2 atmosphere showed pentagon symmetry. The PMN was initially prepared by solid-state reaction. Further, this PMN relaxor material will be used to convert into nanocrystalline PMN by IGCT with sputtering and will be studied.

  6. Generation of high charge state metal ion beams by electron cyclotron resonance heating of vacuum arc plasma in cusp trap.

    Science.gov (United States)

    Nikolaev, A G; Savkin, K P; Oks, E M; Vizir, A V; Yushkov, G Yu; Vodopyanov, A V; Izotov, I V; Mansfeld, D A

    2012-02-01

    A method for generating high charge state heavy metal ion beams based on high power microwave heating of vacuum arc plasma confined in a magnetic trap under electron cyclotron resonance conditions has been developed. A feature of the work described here is the use of a cusp magnetic field with inherent "minimum-B" structure as the confinement geometry, as opposed to a simple mirror device as we have reported on previously. The cusp configuration has been successfully used for microwave heating of gas discharge plasma and extraction from the plasma of highly charged, high current, gaseous ion beams. Now we use the trap for heavy metal ion beam generation. Two different approaches were used for injecting the vacuum arc metal plasma into the trap--axial injection from a miniature arc source located on-axis near the microwave window, and radial injection from sources mounted radially at the midplane of the trap. Here, we describe preliminary results of heating vacuum arc plasma in a cusp magnetic trap by pulsed (400 μs) high power (up to 100 kW) microwave radiation at 37.5 GHz for the generation of highly charged heavy metal ion beams.

  7. A vacuum-sealed, gigawatt-class, repetitively pulsed high-power microwave source

    Science.gov (United States)

    Xun, Tao; Fan, Yu-wei; Yang, Han-wu; Zhang, Zi-cheng; Chen, Dong-qun; Zhang, Jian-de

    2017-06-01

    A compact L-band sealed-tube magnetically insulated transmission line oscillator (MILO) has been developed that does not require bulky external vacuum pump for repetitive operations. This device with a ceramic insulated vacuum interface, a carbon fiber array cathode, and non-evaporable getters has a base vacuum pressure in the low 10-6 Pa range. A dynamic 3-D Monte-Carlo model for the molecular flow movement and collision was setup for the MILO chamber. The pulse desorption, gas evolution, and pressure distribution were exactly simulated. In the 5 Hz repetition rate experiments, using a 600 kV diode voltage and 48 kA beam current, the average radiated microwave power for 25 shots is about 3.4 GW in 45 ns pulse duration. The maximum equilibrium pressure is below 4.0 × 10-2 Pa, and no pulse shortening limitations are observed during the repetitive test in the sealed-tube condition.

  8. Conceptual Design of Vacuum Chamber for testing of high heat flux components using electron beam as a source

    Science.gov (United States)

    Khan, M. S.; Swamy, Rajamannar; Khirwadkar, S. S.; Divertors Division, Prototype

    2012-11-01

    A conceptual design of vacuum chamber is proposed to study the thermal response of high heat flux components under energy depositions of the magnitude and durations expected in plasma fusion devices. It is equipped with high power electron beam with maximum beam power of 200 KW mounted in a stationary horizontal position from back side of the chamber. The electron beam is used as a heat source to evaluate the heat removal capacity, material performance under thermal loads & stresses, thermal fatigue etc on actively cooled mock - ups which are mounted on a flange system which is the front side door of the chamber. The tests mock - ups are connected to a high pressure high temperature water circulation system (HPHT-WCS) operated over a wide range of conditions. The vacuum chamber consists of different ports at different angles to view the mock -up surface available for mock -up diagnostics. The vacuum chamber is pumped with different pumps mounted on side ports of the chamber. The chamber is shielded from X - rays which are generated inside the chamber when high-energy electrons are incident on the mock-up. The design includes development of a conceptual design with theoretical calculations and CAD modelling of the system using CATIA V5. These CAD models give an outline on the complete geometry of HHF test chamber, fabrication challenges and safety issues. FEA analysis of the system has been performed to check the structural integrity when the system is subjected to structural & thermal loads.

  9. Development of High-Voltage Vacuum Circuit Breaker%高电压真空断路器的发展

    Institute of Scientific and Technical Information of China (English)

    吴红亚; 李建基

    2011-01-01

    六氟化硫断路器在高压断路器中居主导地位,而真空断路器在中压领域占绝对优势,并在高电压领域崭露头角。阐述了开发高电压真空断路器的必要性,介绍了现有产品的结构与特点,并提出了研发高电压真空断路器需解决的技术问题及相关的应对措施。%Sulfur hexafluoride circuit breakers take a leading position in high-voltage circuit breakers and vacuum circuit breakers hold all the trumps in medium voltage field,making a figure in high-voltage field.Description was made to the necessity of development of high-voltage vacuum circuit breakers.Introduction was made to structure and features of the existing products.This paper raised technical issues to be solved in RD of high-voltage vacuum circuit breakers and their related countermeasures.

  10. High performance thermal insulation systems (HiPTI). Vacuum insulated products (VIP). Proceedings of the international conference and workshop

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, M.; Bertschinger, H.

    2001-07-01

    These are the proceedings of the International Conference and Workshop held at EMPA Duebendorf, Switzerland, in January 2001. The papers presented at the conference's first day included contributions on the role of high-performance insulation in energy efficiency - providing an overview of available technologies and reviewing physical aspects of heat transfer and the development of thermal insulation as well as the state of the art of glazing technologies such as high-performance and vacuum glazing. Also, vacuum-insulated products (VIP) with fumed silica, applications of VIP systems in technical building systems, nanogels, VIP packaging materials and technologies, measurement of physical properties, VIP for advanced retrofit solutions for buildings and existing and future applications for advanced low energy building are discussed. Finally, research and development concerning VIP for buildings are reported on. The workshops held on the second day covered a preliminary study on high-performance thermal insulation materials with gastight porosity, flexible pipes with high performance thermal insulation, evaluation of modern insulation systems by simulation methods as well as the development of vacuum insulation panels with a stainless steel envelope.

  11. An atomic beam source for fast loading of a magneto-optical trap under high vacuum

    DEFF Research Database (Denmark)

    McDowall, P.D.; Hilliard, Andrew; Grünzweig, T.

    2012-01-01

    is capable of loading 90 of a magneto-optical trap (MOT) in less than 7 s while maintaining a low vacuum pressure of 10 -11 Torr. The transverse velocity components of the atomic beam are measured to be within typical capture velocities of a rubidium MOT. Finally, we show that the atomic beam can be turned...

  12. Surface Effects and Challenges for Application of Piezoelectric Langasite Substrates in Surface Acoustic Wave Devices Caused by High Temperature Annealing under High Vacuum

    Directory of Open Access Journals (Sweden)

    Marietta Seifert

    2015-12-01

    Full Text Available Substrate materials that are high-temperature stable are essential for sensor devices which are applied at high temperatures. Although langasite is suggested as such a material, severe O and Ga diffusion into an O-affine deposited film was observed during annealing at high temperatures under vacuum conditions, leading to a damage of the metallization as well as a change of the properties of the substrate and finally to a failure of the device. Therefore, annealing of bare LGS (La 3 Ga 5 SiO 14 substrates at 800 ∘ C under high vacuum conditions is performed to analyze whether this pretreatment improves the suitability and stability of this material for high temperature applications in vacuum. To reveal the influence of the pretreatment on the subsequently deposited metallization, RuAl thin films are used as they are known to oxidize on LGS at high temperatures. A local study of the pretreated and metallized substrates using transmission electron microscopy reveals strong modification of the substrate surface. Micro cracks are visible. The composition of the substrate is strongly altered at those regions. Severe challenges for the application of LGS substrates under high-temperature vacuum conditions arise from these substrate damages, revealing that the pretreatment does not improve the applicability.

  13. Fundamental Studies of Electronic Properties of Materials and Devices for High Power, Compact Terahertz Vacuum Electron Devices

    Science.gov (United States)

    2011-12-23

    Workshop on Computational Electronics, (full length conference paper) Beijing, China, May 2009, pp. 265-268. Available online through IEEE Xplore ...of traveling-wave tube regenerative oscillators,” IEEE Trans Elec Dev, vol 57, 1152-1159 (2010). [5] P. Gao, J. H. Booske, Z.-H. Yang, B. Li, J. He...J. Temkin, “Vacuum Electronic High Power Terahertz Sources,” invited review paper, Inaugural Issue, IEEE Transactions on Terahertz Science and

  14. Treating osteoporotic vertebral compression fractures with intraosseous vacuum phenomena using high-viscosity bone cement via bilateral percutaneous vertebroplasty.

    Science.gov (United States)

    Guo, Dan; Cai, Jun; Zhang, Shengfei; Zhang, Liang; Feng, Xinmin

    2017-04-01

    Osteoporotic vertebral compression fractures with intraosseous vacuum phenomena could cause persistent back pains in patients, even after receiving conservative treatment. The aim of this study was to evaluate the efficacy of using high-viscosity bone cement via bilateral percutaneous vertebroplasty in treating patients who have osteoporotic vertebral compression fractures with intraosseous vacuum phenomena.Twenty osteoporotic vertebral compression fracture patients with intraosseous vacuum phenomena, who received at least 2 months of conservative treatment, were further treated by injecting high-viscosity bone cement via bilateral percutaneous vertebroplasty due to failure of conservative treatment. Treatment efficacy was evaluated by determining the anterior vertebral compression rates, visual analog scale (VAS) scores, and Oswestry disability index (ODI) scores at 1 day before the operation, on the first day of postoperation, at 1-month postoperation, and at 1-year postoperation.Three of 20 patients had asymptomatic bone cement leakage when treated via percutaneous vertebroplasty; however, no serious complications related to these treatments were observed during the 1-year follow-up period. A statistically significant improvement on the anterior vertebral compression rates, VAS scores, and ODI scores were achieved after percutaneous vertebroplasty. However, differences in the anterior vertebral compression rate, VAS score, and ODI score in the different time points during the 1-year follow-up period was not statistically significant (P > 0.05).Within the limitations of this study, the injection of high-viscosity bone cement via bilateral percutaneous vertebroplasty for patients who have osteoporotic vertebral compression fractures with intraosseous vacuum phenomena significantly relieved their back pains and improved their daily life activities shortly after the operation, thereby improving their life quality. In this study, the use of high-viscosity bone

  15. Technology handbook of vacuum physics

    CERN Document Server

    Beck, A H

    2013-01-01

    Handbook of Vacuum Physics, Volume 3: Technology is part of a series of publications that presents articles featuring the whole spectrum of vacuum physics. This particular volume presents materials that deal with technology concerns in vacuum mechanics. The first material talks about the utilization of ceramic materials in the construction of vacuum devices. The next paper details the application of vacuum physics in soldering and brazing process. The last article deals with the utilization of vacuum technology in high frequency heating. The book will be of great use to professionals involved

  16. Water purification through vacuum system; Purificacion de agua bajo vacio

    Energy Technology Data Exchange (ETDEWEB)

    Armenta-Deu, C.

    2004-07-01

    Fresh water production through vacuum systems are today a reasonable option at a much lower cost than tray conventional units, also based on evaporation-condensation process. The use of simple devices such as vacuum ejectors allows to reduce pressure down to 5 kPa at a very low cost, only 7. The requirement of having a constant water flow to reduce pressure has been easily solved using a close circuit and a low power pump which is powered by solar energy. The energy cost has been reduced dramatically, as the system operates at a very reduced temperature, 45 degree Celsius, and even as low as 35 degree Celsius, what causes a much lower energy requirement. The results obtained during the tests have shown that is possible to save up to 230 kJ per litre of fresh water, and up to 40 W per l/h. The system is fully compatible with thermal solar collectors of low temperature, and can be electrically powered by a solar panel of low power. (Author)

  17. VACUUM TRAP

    Science.gov (United States)

    Gordon, H.S.

    1959-09-15

    An improved adsorption vacuum trap for use in vacuum systems was designed. The distinguishing feature is the placement of a plurality of torsionally deformed metallic fins within a vacuum jacket extending from the walls to the central axis so that substantially all gas molecules pass through the jacket will impinge upon the fin surfaces. T fins are heated by direct metallic conduction, thereby ol taining a uniform temperature at the adeorbing surfaces so that essentially all of the condensible impurities from the evacuating gas are removed from the vacuum system.

  18. Microfabricated triggered vacuum switch

    Science.gov (United States)

    Roesler, Alexander W.; Schare, Joshua M.; Bunch, Kyle

    2010-05-11

    A microfabricated vacuum switch is disclosed which includes a substrate upon which an anode, cathode and trigger electrode are located. A cover is sealed over the substrate under vacuum to complete the vacuum switch. In some embodiments of the present invention, a metal cover can be used in place of the trigger electrode on the substrate. Materials used for the vacuum switch are compatible with high vacuum, relatively high temperature processing. These materials include molybdenum, niobium, copper, tungsten, aluminum and alloys thereof for the anode and cathode. Carbon in the form of graphitic carbon, a diamond-like material, or carbon nanotubes can be used in the trigger electrode. Channels can be optionally formed in the substrate to mitigate against surface breakdown.

  19. Effect of Injection Velocity on Structure Part Characteristic in AZ50 Die Casting Process with High Vacuum System

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    When diecasting large and thin Mg alloy parts, material defects occur, which include porosity, nonuniform mechanical properties, irregular surfaces, and incomplete filling. To resolve these problems, it is necessary to have uniform injection velocities and temperatures as well as control the melt. This study investigated the feasibility of producing large and thin components using a die caster by attaching a high vacuum system. In particular, the effects of injection velocity on surface quality and the mechanical properties of the products were investigated. Hence, an injection velocity scheme and a die structure capable of casting in a vacuum were proposed. As a result, it was found that the critical low injection velocity was 0.2 m/s to produce large thin Mg alloy structures having good mechanical properties.

  20. The source of X-rays and high-charged ions based on moderate power vacuum discharge with laser triggering

    Directory of Open Access Journals (Sweden)

    Alkhimova Mariya A.

    2015-06-01

    Full Text Available The source of X-ray radiation with the energy of quanta that may vary in the range hν = 1÷12 keV was developed for studies in X-ray interaction with matter and modification of solid surfaces. It was based on a vacuum spark discharge with the laser triggering. It was shown in our experiments that there is a possibility to adjust X-ray radiation spectrum by changing the configuration of the electrode system when the energy stored in the capacitor is varied within the range of 1÷17 J. A comprehensive study of X-ray imaging and quanta energy was carried out. These experiments were carried out for the case of both direct and reverse polarity of the voltage on the electrodes. Additionally, ion composition of plasma created in a laser-triggered vacuum discharge was analyzed. Highly charged ions Zn(+21, Cu(+20 and Fe(+18 were observed.

  1. Vacuum Technology

    Energy Technology Data Exchange (ETDEWEB)

    Biltoft, P J

    2004-10-15

    The environmental condition called vacuum is created any time the pressure of a gas is reduced compared to atmospheric pressure. On earth we typically create a vacuum by connecting a pump capable of moving gas to a relatively leak free vessel. Through operation of the gas pump the number of gas molecules per unit volume is decreased within the vessel. As soon as one creates a vacuum natural forces (in this case entropy) work to restore equilibrium pressure; the practical effect of this is that gas molecules attempt to enter the evacuated space by any means possible. It is useful to think of vacuum in terms of a gas at a pressure below atmospheric pressure. In even the best vacuum vessels ever created there are approximately 3,500,000 molecules of gas per cubic meter of volume remaining inside the vessel. The lowest pressure environment known is in interstellar space where there are approximately four molecules of gas per cubic meter. Researchers are currently developing vacuum technology components (pumps, gauges, valves, etc.) using micro electro mechanical systems (MEMS) technology. Miniature vacuum components and systems will open the possibility for significant savings in energy cost and will open the doors to advances in electronics, manufacturing and semiconductor fabrication. In conclusion, an understanding of the basic principles of vacuum technology as presented in this summary is essential for the successful execution of all projects that involve vacuum technology. Using the principles described above, a practitioner of vacuum technology can design a vacuum system that will achieve the project requirements.

  2. A High-resolution Vacuum Ultraviolet Laser Photoionization and Photoelectron Study of the Co Atom

    Science.gov (United States)

    Huang, Huang; Wang, Hailing; Luo, Zhihong; Shi, Xiaoyu; Chang, Yih-Chung; Ng, C. Y.

    2016-12-01

    We have measured the vacuum ultraviolet-photoionization efficiency (VUV-PIE) spectrum of Co in the energy range of 63,500-67,000 cm-1, which covers the photoionization transitions of Co(3d74s2 4F9/2) \\to Co+(3d8 3F4), Co(3d74s2 4F7/2) \\to Co+(3d8 3F3), Co(3d74s2 4F9/2) \\to Co+(3d8 3F3), Co(3d74s2 4F9/2) \\to Co+(3d8 3F2), and Co(3d74s2 4F9/2) \\to Co+(3d74s1 5F5). We have also recorded the pulsed field ionization photoelectron spectrum of Co in the same energy range, allowing accurate determinations of ionization energies (IEs) for the photoionization transitions from the Co(3d74s2 4F9/2) ground neutral state to the Co+(3F J ) (J = 4 and 3) and Co+(5F5) ionic states, as well as from the Co(3d74s2 4F7/2) excited neural state to the Co+(3d8 3F3) ionic state. The high-resolution nature of the VUV laser used has allowed the observation of many well-resolved autoionizing resonances in the VUV-PIE spectrum, among which an autoionizing Rydberg series, 3d74s1(5F5)np (n = 19-38), converging to the Co+(3d74s1 5F5) ionic state from the Co(3d74s2 4F9/2) ground neutral state is identified. The fact that no discernible step-like structures are present at these ionization thresholds in the VUV-PIE spectrum indicates that direct photoionization of Co is minor compared to autoionization in this energy range. The IE values, the autoionizing Rydberg series, and the photoionization cross sections obtained in this experiment are valuable for understanding the VUV opacity and abundance measurement of the Co atom in stars and solar atmospheres, as well as for benchmarking the theoretical results calculated in the Opacity Project and the IRON Project, and thus are of relevance to astrophysics.

  3. Ultrahigh vacuum/high pressure chamber for surface x-ray diffraction experiments

    Science.gov (United States)

    Bernard, P.; Peters, K.; Alvarez, J.; Ferrer, S.

    1999-02-01

    We describe an ultrahigh vacuum chamber that can be internally pressurized to several bars and that is designed to perform surface x-ray diffraction experiments on solid-gas interfaces. The chamber has a cylindrical beryllium window that serves as the entrance and exit for the x rays. The sample surface can be ion bombarded with an ancillary ion gun and annealed to 1200 K.

  4. Vacuum extraction

    DEFF Research Database (Denmark)

    Maagaard, Mathilde; Oestergaard, Jeanett; Johansen, Marianne

    2012-01-01

    Objectives. To develop and validate an Objective Structured Assessment of Technical Skills (OSATS) scale for vacuum extraction. Design. Two part study design: Primarily, development of a procedure-specific checklist for vacuum extraction. Hereafter, validationof the developed OSATS scale for vacuum...... extraction in a prospective observational study. Setting. Rigshospitalet, University Hospital of Copenhagen. Population. For development an obstetric expert from each labor ward in Denmark (28 departments) were invited to participate. For validation nine first-year residents and ten chief physicians...... with daily work in the obstetric field were tested. Methods. The Delphi method was used for development of the scale. In a simulated vacuum extraction scenario first-year residents and obstetric chief physicians were rated using the developed OSATS scale for vacuum extraction to test construct validity...

  5. Vacuum extraction

    DEFF Research Database (Denmark)

    Maagaard, Mathilde; Oestergaard, Jeanett; Johansen, Marianne

    2012-01-01

    Objectives. To develop and validate an Objective Structured Assessment of Technical Skills (OSATS) scale for vacuum extraction. Design. Two part study design: Primarily, development of a procedure-specific checklist for vacuum extraction. Hereafter, validationof the developed OSATS scale for vacuum...... extraction in a prospective observational study. Setting. Rigshospitalet, University Hospital of Copenhagen. Population. For development an obstetric expert from each labor ward in Denmark (28 departments) were invited to participate. For validation nine first-year residents and ten chief physicians...... with daily work in the obstetric field were tested. Methods. The Delphi method was used for development of the scale. In a simulated vacuum extraction scenario first-year residents and obstetric chief physicians were rated using the developed OSATS scale for vacuum extraction to test construct validity...

  6. Gravitational vacuum

    Science.gov (United States)

    Grigoryan, L. S.; Saakyan, G. S.

    1984-09-01

    The existence of a special gravitational vacuum is considered in this paper. A phenomenological method differing from the traditional Einsteinian formalization is utilized. Vacuum, metric and matter form a complex determined by field equations and at great distances from gravitational masses vacuum effects are small but could be large in powerful fields. Singularities and black holes justify the approach as well as the Ambartsmyan theory concerning the existence of supermassive and superdense prestallar bodies that then disintegrate. A theory for these superdense bodies is developed involving gravitational field equations that describe the vacuum by an energy momentum tensor and define the field and mass distribution. Computations based on the theory for gravitational radii with incompressible liquid models adequately reflecting real conditions indicate that a gravitational vacuum could have considerable effects on superdense stars and could have radical effects for very large masses.

  7. Preventing and Reversing Vacuum-Induced Optical Losses in High-Finesse Tantalum (V) Oxide Mirror Coatings

    CERN Document Server

    Gangloff, Dorian; Wu, Tailin; Bylinskii, Alexei; Braverman, Boris; Gutierrez, Michael; Nichols, Rosanna; Li, Junru; Aichholz, Kai; Cetina, Marko; Karpa, Leon; Jelenković, Branislav; Chuang, Isaac; Vuletić, Vladan

    2015-01-01

    We study the vacuum-induced degradation of high-finesse optical cavities with mirror coatings composed of SiO$_2$-Ta$_{2}$O$_{5}$ dielectric stacks, and present methods to protect these coatings and to recover their initial quality factor. For separate coatings with reflectivities centered at 370 nm and 422 nm, a vacuum-induced continuous increase in optical loss occurs if the surface-layer coating is made of Ta$_{2}$O$_{5}$, while it does not occur if it is made of SiO$_2$. The incurred optical loss can be reversed by filling the vacuum chamber with oxygen at atmospheric pressure, and the recovery rate can be strongly accelerated by continuous laser illumination at 422 nm. Both the degradation and the recovery processes depend strongly on temperature. We find that a 1 nm-thick layer of SiO$_2$ passivating the Ta$_{2}$O$_{5}$ surface layer is sufficient to reduce the degradation rate by more than a factor of 10, strongly supporting surface oxygen depletion as the primary degradation mechanism.

  8. Metals and metal oxides particles produced by pulsed laser ablation under high vacuum

    OpenAIRE

    SIRAJ, Khurram; TABASSUM, Yasir SOHAIL and Aasma

    2011-01-01

    A pulsed KrF Excimer laser (248 nm, 15 mJ) was utilized to synthesize different particles on (111) Si substrate under vacuum \\sim 10-6 torr using Aluminum (Al), Platinum (Pt), Tungsten (W), Molybdenum (Mo), Cadmium Oxide (CdO), and Yttrium Oxide (Y2O3) targets. Scanning electron microscope (SEM) was used to study particle size distribution on silicon substrate. The size of individual metal particles was found to be ranging from 71 nm to 2 m m whereas metal oxides particles were found...

  9. Production of ceramic-metal joints for high-vacuum applications and development of simulation program for discharge tube

    Energy Technology Data Exchange (ETDEWEB)

    Kang, S. H.; Chung, K. H. [Seoul National University, Seoul (Korea)

    2000-04-01

    To develop a ceramic-metal jointed tube for high-vacuum applications, metalizing process and active metal brazing were investigated. Active metal brazing was adopted as a joining process to produce a high-vacuum tube which had high joint strength and reliability. A possibility for the development of new composition of Mo-Mn paste was studied. Also, to improve the strength and reliability of active metal brazed joint, TiN coating was introduced as a diffusion barrier. It was revealed that TiN coating could improve the joint strength and reliability. 100mm {phi} tube joint was produced using incusil ABA brazing alloy. The strength and reliability of manufactured tube showed higher value than commercial one. The electric field distribution in ceramic tube under high voltage was analyzed. Two dimensional electric field distribution was investigated under the existence of charged particles. From this result, electric field distribution at the surface of ceramic tube and the location of high electric field was predicted. Finally, Arc discharge was simulated to analyze the effect of arc discharge on the discharge tube wall. The maximum temperature of arc was 12000-13000K. The wall temperature was increased 100-170K by the arc discharge. 45 refs., 57 figs., 4 tabs. (Author)

  10. Production of ceramic-metal joints for high-vacuum applications and development of simulation program for discharge tube

    Energy Technology Data Exchange (ETDEWEB)

    Kang, S. H.; Chung, K. H. [Seoul National University, Seoul (Korea)

    2000-04-01

    To develop a ceramic-metal jointed tube for high-vacuum applications, metalizing process and active metal brazing were investigated. Active metal brazing was adopted as a joining process to produce a high-vacuum tube which had high joint strength and reliability. A possibility for the development of new composition of Mo-Mn paste was studied. Also, to improve the strength and reliability of active metal brazed joint, TiN coating was introduced as a diffusion barrier. It was revealed that TiN coating could improve the joint strength and reliability. 100mm {phi} tube joint was produced using incusil ABA brazing alloy. The strength and reliability of manufactured tube showed higher value than commercial one. The electric field distribution in ceramic tube under high voltage was analyzed. Two dimensional electric field distribution was investigated under the existence of charged particles. From this result, electric field distribution at the surface of ceramic tube and the location of high electric field was predicted. Finally, Arc discharge was simulated to analyze the effect of arc discharge on the discharge tube wall. The maximum temperature of arc was 12000-13000K. The wall temperature was increased 100-170K by the arc discharge. 45 refs., 57 figs., 4 tabs. (Author)

  11. Quasi-adiabatic vacuum-based column housing for very high-pressure liquid chromatography.

    Science.gov (United States)

    Gritti, Fabrice; Gilar, Martin; Jarrell, Joseph A

    2016-07-22

    A prototype vacuum-based (10(-6)Torr) column housing was built to thermally isolate the chromatographic column from the external air environment. The heat transfer mechanism is solely controlled by surface radiation, which was minimized by wrapping the column with low-emissivity aluminum tape. The adiabaticity of the column housing was quantitatively assessed from the measurement of the operational pressure and fluid temperature at the outlet of a 2.1mm×100mm column (sub-2 μm particles). The pressure drop along the column was raised up to 1kbar. The enthalpy balance of the eluent (water, acetonitrile, and one water/acetonitrile mixture, 70/30, v/v) showed that less than 1% of the viscous heat generated by friction of the fluid against the packed bed was lost to the external air environment. Such a vacuum-based column oven minimizes the amplitude of the radial temperature gradients across the column diameter and maximizes its resolving power.

  12. A vacuum double-crystal spectrometer for reference-free highly charged ions X-ray spectroscopy

    CERN Document Server

    Amaro, P; Schlesser, S; Gumberidze, Alexandre; Kessler, Ernest G; Henins, Albert; Bigot, E -O Le; Trassinelli, M; Isac, Jean-Michel; Travers, Pascal; Guerra, Mauro; Santos, J P; Indelicato, Paul

    2012-01-01

    We have built a vacuum double crystal spectrometer, which coupled to an electron-cyclotron resonance ion source, allows to measure low-energy x-ray transitions in highly-charged ions with accuracies of the order of a few parts per million. We describe in detail the instrument and its performances. Furthermore, we present a few spectra of transitions in Ar$^{14+}$, Ar$^{15+}$ and Ar$^{16+}$. We have developed an \\emph{ab initio} simulation code that allows us to obtain accurate line profiles. It can reproduce experimental spectra with unprecedented accuracy. The quality of the profiles allows the direct determination of line width.

  13. Trapping of xenon gas in closed inner spaces of carbon nanomaterials for stable gas storage under high-vacuum condition

    Science.gov (United States)

    Kobayashi, Keita; Yasuda, Hidehiro

    2017-01-01

    Xe gas can be trapped in the closed inner spaces of glassy carbon derived from C60 fullerene by thermal coalescence of C60 in Xe atmosphere and in cap-opened carbon nanotubes (CNTs) covered with an ionic liquid by soaking Xe-adsorbing CNTs in an ionic liquid. The trapped Xe gas is detected by energy dispersive X-ray spectrometry using a spectrometer mounted on an analytical transmission electron microscope. The closed inner spaces store gas molecules even under high-vacuum condition (˜10-5 Pa).

  14. Probing vacuum birefringence under a high-intensity laser field with gamma-ray polarimetry at the GeV scale

    CERN Document Server

    Nakamiya, Yoshihide; Moritaka, Toseo; Seto, Keita

    2015-01-01

    Probing vacuum structures deformed by high intense fields is of great interest in general. In the context of quantum electrodynamics (QED), the vacuum exposed by a linearly polarized high-intensity laser field is expected to show birefringence. We consider the combination of a 10 PW laser system to pump the vacuum and 1 GeV gamma-rays to probe the birefringent effect. The vacuum birefringence can be measured via the polarization flip of the probe gamma-rays. We discuss the design of the gamma-ray polarimeter and then evaluate the measurability of the reduction of the degree of linear polarization due to the appearance of birefringence. We found that the measurement is indeed feasible given a realistic set of laser parameters and achievable pulse statistics.

  15. Carbon Nanotube-based Cold Cathode for High Power MicrowaveVacuum Electronic Devices: A Potential Field Emitter

    Directory of Open Access Journals (Sweden)

    P. Verma

    2008-09-01

    Full Text Available Carbon nanotubes (CNTs can be grown in the form of small, sharp spikes capable of carrying very highcurrent densities which suggest great potential application of CNTs as cold cathode in high power microwavevacuum device applications. These cold cathode vacuum microwave devices are expected to be ideally suitedfor air-borne and space applications. This paper  reports the initial efforts made in the development of coldcathode using PECVD grown vertically-aligned matrix of CNTs with uniform height and optimum tip densityon silicon substrate. The high aspect ratio (of the order of 10,000 and novel electrical, mechanical, and thermalproperties of the CNT are found to be very attractive characteristics for emission of large and stable currentdensities at reasonably low field. The field emission current voltage characteristics of a typical cathode gaveemission current density in excess of 35 mA/cm2 at reasonably low field. The emission current in most of thesamples is found to be stable over long period of time but is greatly effected by the vacuum condition duringmeasurement. The initial measured data suggests great promise for achieving high current densities at practicalelectric fields.Defence Science Journal, 2008, 58(5, pp.650-654, DOI:http://dx.doi.org/10.14429/dsj.58.1688

  16. Electron-beam-ignited, high-frequency-driven vacuum ultraviolet excimer light source

    CERN Document Server

    Dandl, T; Heindl, T; Krücken, R; Wieser, J; Ulrich, A

    2015-01-01

    Transformation of a table-top electron beam sustained 2.45 GHz RF discharge in rare gases into a self burning discharge has been observed for increasing RF-amplitude. Thereby, the emission spectrum undergoes significant changes in a wide spectral range from the vacuum ultraviolet (VUV) to the near infrared. A strong increase of VUV excimer emission is observed for the self burning discharge. The so called first excimer continuum, in particular, shows a drastic increase in intensity. For argon this effect results in a brilliant light source emitting near the 105 nm short wavelength cutoff of LiF windows. The appearance of a broad-band continuum in the UV and visible range as well as effects of RF excitation on the atomic line radiation and the so called third excimer continuum are briefly described.

  17. Photochemical/Microchannel Plasma Reactors Driven By High Power Vacuum Ultraviolet Lamps

    Science.gov (United States)

    Shin, Chul; Park, Sung-Jin; Eden, Gary

    2016-09-01

    Experiments are being conducted in which molecular dissociation or other chemical reactions in microchannel plasmas are accelerated by the introduction of vacuum ultraviolet photons. Initial emphasis is being placed on recently-developed Xe2 lamps that are efficient sources of 172 nm (h ν 7.2 eV) photons. Thin, flat lamps, fabricated from fused silica and having microcavity arrays internal to the lamp, have been developed by the University of Illinois and Eden Park Illumination and produce intensities above 200 mW/cm2. Integrating such lamps into a microcavity plasma reactor yields a hybrid photochemical/plasma system in which product yield and power consumption can be optimized. The selectivity of photodissociation in generating radicals and atomic fragments offers new synergies in plasma processing. Data concerning CO2 dissociation in arrays of microchannel plasmas, and the modification of this process by external 172 nm radiation, will be presented.

  18. Large-Area and High-Throughput PDMS Microfluidic Chip Fabrication Assisted by Vacuum Airbag Laminator

    Directory of Open Access Journals (Sweden)

    Shuting Xie

    2017-07-01

    Full Text Available One of the key fabrication steps of large-area microfluidic devices is the flexible-to-hard sheet alignment and pre-bonding. In this work, the vacuum airbag laminator (VAL which is commonly used for liquid crystal display (LCD production has been applied for large-area microfluidic device fabrication. A straightforward, efficient, and low-cost method has been achieved for 400 × 500 mm2 microfluidic device fabrication. VAL provides the advantages of precise alignment and lamination without bubbles. Thermal treatment has been applied to achieve strong PDMS–glass and PDMS–PDMS bonding with maximum breakup pressure of 739 kPa, which is comparable to interference-assisted thermal bonding method. The fabricated 152 × 152 mm2 microfluidic chip has been successfully applied for droplet generation and splitting.

  19. Vacuum brazing of high volume fraction SiC particles reinforced aluminum matrix composites

    Science.gov (United States)

    Cheng, Dongfeng; Niu, Jitai; Gao, Zeng; Wang, Peng

    2015-03-01

    This experiment chooses A356 aluminum matrix composites containing 55% SiC particle reinforcing phase as the parent metal and Al-Si-Cu-Zn-Ni alloy metal as the filler metal. The brazing process is carried out in vacuum brazing furnace at the temperature of 550°C and 560°C for 3 min, respectively. The interfacial microstructures and fracture surfaces are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy spectrum analysis (EDS). The result shows that adequacy of element diffusion are superior when brazing at 560°C, because of higher activity and liquidity. Dislocations and twins are observed at the interface between filler and composite due to the different expansion coefficient of the aluminum alloy matrix and SiC particles. The fracture analysis shows that the brittle fracture mainly located at interface of filler and composites.

  20. Vacuum phenomenon.

    Science.gov (United States)

    Yanagawa, Youichi; Ohsaka, Hiromichi; Jitsuiki, Kei; Yoshizawa, Toshihiko; Takeuchi, Ikuto; Omori, Kazuhiko; Oode, Yasumasa; Ishikawa, Kouhei

    2016-08-01

    This article describes the theory of the formation of the vacuum phenomenon (VP), the detection of the VP, the different medical causes, the different locations of the presentation of the VP, and the differential diagnoses. In the human body, the cavitation effect is recognized on radiological studies; it is called the VP. The mechanism responsible for the formation of the VP is as follows: if an enclosed tissue space is allowed to expand as a rebound phenomenon after an external impact, the volume within the enclosed space will increase. In the setting of expanding volume, the pressure within the space will decrease. The solubility of the gas in the enclosed space will decrease as the pressure of the space decreases. Decreased solubility allows a gas to leave a solution. Clinically, the pathologies associated with the VP have been reported to mainly include the normal joint motion, degeneration of the intervertebral discs or joints, and trauma. The frequent use of CT for trauma patients and the high spatial resolution of CT images might produce the greatest number of chances to detect the VP in trauma patients. The VP is observed at locations that experience a traumatic impact; thus, an analysis of the VP may be useful for elucidating the mechanism of an injury. When the VP is located in the abdomen, it is important to include perforation of the digestive tract in the differential diagnosis. The presence of the VP in trauma patients does not itself influence the final outcome.

  1. High-temperature compatible 3D-integration processes for a vacuum-sealed CNT-based NEMS

    Science.gov (United States)

    Gueye, R.; Lee, S. W.; Akiyama, T.; Briand, D.; Roman, C.; Hierold, C.; de Rooij, N. F.

    2013-03-01

    A System-in-Package (SiP) concept for the 3D-integration of a Single Wall Carbon Nanotube (SWCNT) resonator with its CMOS driving electronics is presented. The key element of this advanced SiP is the monolithic 3D-integration of the MEMS with the CMOS electronics using Through Silicon Vias (TSVs) on an SOI wafer. This SiP includes: A glass cap vacuum-sealed to the main wafer using an eutectic bonding process: a low leak rate of 2.7 10-9 mbar•l/s was obtained; Platinum-TSVs, compatible with the SWCNT growth and release process; The TSVs were developed in a "via first" process and characterized at high-temperature — up to 850 °C. An ohmic contact between the Pt-metallization and the SOI silicon device layer was obtained; The driving CMOS electronic device is assembled to the MEMS using an Au stud bump technology. Keywords: System-in-Package (SiP), vacuum packaging, eutectic bonding, "via-first" TSVs, high-temperature platinum interconnects, ohmic contacts, Au-stud bumps assembly, CMOS electronics.

  2. Design and fabrication of high performance wafer-level vacuum packaging based on glass-silicon-glass bonding techniques

    Science.gov (United States)

    Zhang, Jinwen; Jiang, Wei; Wang, Xin; Zhou, Jilong; Yang, Huabing

    2012-12-01

    In this paper, a high performance wafer-level vacuum packaging technology based on GSG triple-layer sealing structure for encapsulating large mass inertial MEMS devices fabricated by silicon-on-glass bulk micromachining technology is presented. Roughness controlling strategy of bonding surfaces was proposed and described in detail. Silicon substrate was thinned and polished by CMP after the first bonding with the glass substrate and was then bonded with the glass micro-cap. Zr thin film was embedded into the concave of the micro-cap by a shadow-mask technique. The glass substrate was thinned to about 100 µm, wet etched through and metalized for realizing vertical feedthrough. During the fabrication, all patterning processes were operated carefully so as to reduce extrusive fragments to as little as possible. In addition, a high-performance micro-Pirani vacuum gauge was integrated into the package for monitoring the pressure and the leak rate further. The result shows that the pressure in the package is about 120 Pa and has no obvious change for more than one year indicating 10-13 stdcc s-1 leak rate.

  3. Test of the beam effect on vacuum arc occurrence in a high-gradient accelerating structure for the CLIC project

    CERN Document Server

    AUTHOR|(CDS)2130409; Gagliardi, Martino

    A new generation of lepton colliders capable of reaching TeV energies is pres- ently under development, and to succeed in this task it is necessary to show that the technology for such a machine is available. The Compact Linear Collider (CLIC) is a possible design option among the future lepton collider projects. It consists of two normal-conducting linacs. Accelerating structures with a gradient of the order of 100 MV/m are necessary to reach the required high energies within a reasonable machine length. One of the strictest require- ments for such accelerating structures is a relatively low occurrence of vacuum arcs. CLIC prototype structures have been tested in the past, but only in absence of beam. In order to proof the feasibility of the high gradient technology for building a functional collider, it is necessary to understand the effect of the beam presence on the vacuum breakdowns. Tests of this type have never been performed previously. The main goal of this work is to provide a first measurement of t...

  4. Vacuum Incalescence

    CERN Document Server

    Intravaia, F

    2016-01-01

    In quantum theory the vacuum is defined as a state of minimum energy that is devoid of particles but still not completely empty. It is perhaps more surprising that its definition depends on the geometry of the system and on the trajectory of an observer through space-time. Along these lines we investigate the case of an atom flying at constant velocity near a planar surface. Using general concepts of statistical mechanics it is shown that the motion-modified interaction with the electromagnetic vacuum is formally equivalent to the interaction with a thermal field having an effective temperature determined by the atom's velocity and distance from the surface. This result suggests new ways to experimentally investigate the properties of the quantum vacuum in non-equilibrium systems and effects such as quantum friction.

  5. Multifunctional ultra-high vacuum apparatus for studies of the interactions of chemical warfare agents on complex surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Wilmsmeyer, Amanda R.; Morris, John R. [Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061 (United States); Gordon, Wesley O.; Mantooth, Brent A.; Lalain, Teri A. [Research and Technology Directorate, U.S. Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, Maryland 21010 (United States); Davis, Erin Durke [OptiMetrics, Inc., Abingdon, Maryland 21009 (United States)

    2014-01-15

    A fundamental understanding of the surface chemistry of chemical warfare agents is needed to fully predict the interaction of these toxic molecules with militarily relevant materials, catalysts, and environmental surfaces. For example, rules for predicting the surface chemistry of agents can be applied to the creation of next generation decontaminants, reactive coatings, and protective materials for the warfighter. Here, we describe a multifunctional ultra-high vacuum instrument for conducting comprehensive studies of the adsorption, desorption, and surface chemistry of chemical warfare agents on model and militarily relevant surfaces. The system applies reflection-absorption infrared spectroscopy, x-ray photoelectron spectroscopy, and mass spectrometry to study adsorption and surface reactions of chemical warfare agents. Several novel components have been developed to address the unique safety and sample exposure challenges that accompany the research of these toxic, often very low vapor pressure, compounds. While results of vacuum-based surface science techniques may not necessarily translate directly to environmental processes, learning about the fundamental chemistry will begin to inform scientists about the critical aspects that impact real-world applications.

  6. arXiv Analytical methods for vacuum simulations in high energy accelerators for future machines based on LHC performances

    CERN Document Server

    Aichinger, Ida; Chiggiato, Paolo

    The Future Circular Collider (FCC), currently in the design phase, will address many outstanding questions in particle physics. The technology to succeed in this 100 km circumference collider goes beyond present limits. Ultra-high vacuum conditions in the beam pipe is one essential requirement to provide a smooth operation. Different physics phenomena as photon-, ion- and electron- induced desorption and thermal outgassing of the chamber walls challenge this requirement. This paper presents an analytical model and a computer code PyVASCO that supports the design of a stable vacuum system by providing an overview of all the gas dynamics happening inside the beam pipes. A mass balance equation system describes the density distribution of the four dominating gas species $\\text{H}_2, \\text{CH}_4$, $\\text{CO}$ and $\\text{CO}_2$. An appropriate solving algorithm is discussed in detail and a validation of the model including a comparison of the output to the readings of LHC gauges is presented. This enables the eval...

  7. Vacuum chamber with distributed titanium sublimation pumping for the G-line wiggler at Cornell High Energy Synchrotron Source

    Science.gov (United States)

    Li, Y.; He, Y.; Mistry, N. B.

    2003-07-01

    This article describes a 3-m-long vacuum chamber for the new wiggler magnet at the Cornell Electron Storage Ring (CESR) for the synchrotron light beam line of the Cornell High Energy Synchrotron Source (CHESS). Copper was chosen as the main chamber material for its good electric and thermal conductivities. Proper mechanical design and welding procedure were implemented to meet very tight tolerances to ensure adequate vertical aperture for the stored beams in CESR while allowing the required small wiggler gap. Distributed titanium sublimation pumping is incorporated along the 3 m length of the chamber to provide sufficient pumping speed and capacity for CESR and CHESS operations. The chamber pumping performance was evaluated prior to installation. Linear distributed pumping speeds at the beam line of ~720 l/s/m for N2 and CO and ~4000 l/s/m for H2 were measured. The measured pumping capacities for N2, CO and H2 are ~1.0, ~2.0 and ~77 Torr l, respectively, for each titanium sublimation cycle. Measurements also showed that CO molecules adsorb on the N2 and H2 saturated titanium films with virtually the same initial sticking coefficient as on a fresh titanium film. Analyses indicated very different CO adsorption mechanisms between the N2 and H2 saturated titanium films. While the replacement of surface H2 by CO was observed, little desorption of nitrogen was measured. Operational experience showed excellent vacuum pumping performance over two years after the chamber installation.

  8. Electron stimulated carbon adsorption in ultra high vacuum monitored by Auger Electron Spectroscopy (AES)

    CERN Document Server

    Scheuerlein, C

    2001-01-01

    Electron stimulated carbon adsorption at room temperature (RT) has been studied in the context of radiation induced surface modifications in the vacuum system of particle accelerators. The stimulated carbon adsorption was monitored by AES during continuous irradiation by 2.5 keV electrons and simultaneous exposure of the sample surface to CO, CO2 or CH4. The amount of adsorbed carbon was estimated by measuring the carbon Auger peak intensity as a function of the electron irradiation time. Investigated substrate materials are technical OFE copper and TiZrV non-evaporable getter (NEG) thin film coatings, which are saturated either in air or by CO exposure inside the Auger electron spectrometer. On the copper substrate electron induced carbon adsorption from gas phase CO and CO2 is below the detection limit of AES. During electron irradiation of the non-activated TiZrV getter thin films, electron stimulated carbon adsorption from gas phase molecules is detected when either CO or CO2 is injected, whereas the CH4 ...

  9. Fractal model for evaluating heat transfer of high temperature porous corundum shell in vacuum investment casting

    Directory of Open Access Journals (Sweden)

    WAN Xin

    2006-02-01

    Full Text Available Under vacuum, heat transfer in porous corundum shell of investment casting depends on the characteristics of the solid materials and the spatial arrangement of solids and pores. In this study, we present a modified fractal approach to model the pore structure of corundum shell and to describe its influence on the thermal conductivity. We assumed that there is no heat convection in the shell. A sectioned view of porous corundum shell was studied and used to describe the geometric structure and to calculate the fractal dimension d. Based on the fractal dimension d, we obtained the relationship between volumetric solid content and pore arrangement in different measure scales. A heat transfer model was thus established using a network of resistors in which we applied an equivalent approach to calculate the effective thermal conductivity of real porous corundum shell that include the effects of heat conduction and heat radiation of solid. From the obtained results we discuss these effects on the effective thermal conductivity including the scale of measurement, the structure of pore and the temperature. At last these results were compared with other empirical model, which computed by assuming even porosity in which effect of pore structure was not being considered. Though the thermal conductivity calculated essentially in agreement with that obtained from empirical model, model used in this study is more close to the real heat transfer process.

  10. Investigations of the electrical breakdown properties of insulator materials used in high voltage vacuum diodes

    Energy Technology Data Exchange (ETDEWEB)

    Shurter, R.P.; Carlson, R.L.; Melton, J.G.

    1993-08-01

    The Injector for the proposed Dual-Axis Radiographic Hydrodynamic Testing (DARHT) Facility at Los Alamos utilizes a monolithic insulator deployed in a radial configuration. The 1.83-m-diam {times} 25.4-cm-thick insulator with embedded grading rings separates the output oil transmission line from the vacuum vessel that contains the re-entrant anode and cathode assemblies. Although much work has been done by the pulse power community in studying surface flash-over of insulating materials used in both axial and radial configurations, dendrite growth at the roots of grading rings embedded in materials suitable for very large insulators is less well characterized. Degradation of several acrylic insulators has been observed in the form of dendrites growing at the roots of the grading rings for large numbers (100`s) of pulses on the prototype DARHT Injector and other machines using similar radial geometries. In a few cases, these dendrites have led to catastrophic bulk breakdown of the acrylic between two grading rings making the insulator a costly loss. Insulating materials under investigation are acrylic (Lucite), epoxy (Furane), and cross-linked polystyrene (Rexolite); each of these materials has its own particular mechanical and electrical merits. All of these materials have been cast and machined into the required large size for the Injector. Test methods and the results of investigations into the breakdown strength of various interface geometries and the susceptibility of these materials to dendrite growth are reported.

  11. High-intensity coherent vacuum ultraviolet source using unfocussed commercial dye lasers.

    Science.gov (United States)

    Albert, Daniel R; Proctor, David L; Davis, H Floyd

    2013-06-01

    Using two or three commercial pulsed nanosecond dye lasers pumped by a single 30 Hz Nd:YAG laser, generation of 0.10 mJ pulses at 125 nm (6 × 10(13) photons∕pulse) has been demonstrated by resonance enhanced four-wave mixing of collimated (unfocussed) laser beams in mercury (Hg) vapor. Phase matching at various vacuum ultraviolet (VUV) wavelengths is achieved by tuning one laser in the vicinity of the 6 (1)S0 → 6 (3)P1 resonance near 253.1 nm. A number of different mixing schemes are characterized. Our observations using broadband lasers (~0.15 cm(-1) bandwidths) are compared to previous calculations pertaining to four-wave mixing of low intensity narrowband laser beams. Prospects for further increases in pulse energies are discussed. We find that VUV tuning curves and intensities are in good agreement with theoretical predictions. The utility of the VUV light source is demonstrated by "soft universal" single-photon VUV ionization in crossed molecular beam studies and for generation of light at 130.2 nm for oxygen atom Rydberg time-of-flight experiments.

  12. Cooling of the Mechanical Motion of Diamond Nanocrystals in a Magneto-Gravitational Trap in High Vacuum

    Science.gov (United States)

    Hsu, Jen-Feng; Ji, Peng; Lewandowski, Charles W.; D'Urso, Brian

    2016-05-01

    We present a magneto-gravitational trap for diamagnetic particles, such as diamond nanocrystals, with stable trapping from atmospheric pressure to high vacuum. Characterization and feedback cooling of the mechanical motion of the trapped particle are described. This static trap is achieved by permanent magnets and ferromagnetic pole pieces. The magnetic field confines the particle in two dimensions, while confinement in the third dimension relies on gravity. The weak trapping forces result in mechanical oscillation frequencies in the extremely low to super low frequency range and exceptionally high sensitivity to external forces. Particles can be trapped for an indefinite length of time without active cooling. With feedback, the mechanical motion can be cooled by several orders of magnitude. With trapped diamond nanocrystals containing nitrogen-vacancy centers, the system has potential as a platform for experiments in quantum nanomechanics. This material is based upon work supported by the National Science Foundation under Grant No. 1540879.

  13. Fabrication of ZnO Nanowires Arrays by Anodization and High-Vacuum Die Casting Technique, and Their Piezoelectric Properties.

    Science.gov (United States)

    Kuo, Chin-Guo; Chang, Ho; Wang, Jian-Hao

    2016-03-24

    In this investigation, anodic aluminum oxide (AAO) with arrayed and regularly arranged nanopores is used as a template in the high-vacuum die casting of molten zinc metal (Zn) into the nanopores. The proposed technique yields arrayed Zn nanowires with an aspect ratio of over 600. After annealing, arrayed zinc oxide (ZnO) nanowires are obtained. Varying the anodizing time yields AAO templates with thicknesses of approximately 50 μm, 60 μm, and 70 μm that can be used in the fabrication of nanowires of three lengths with high aspect ratios. Experimental results reveal that a longer nanowire generates a greater measured piezoelectric current. The ZnO nanowires that are fabricated using an alumina template are anodized for 7 h and produce higher piezoelectric current of up to 69 pA.

  14. Fabrication of ZnO Nanowires Arrays by Anodization and High-Vacuum Die Casting Technique, and Their Piezoelectric Properties

    Directory of Open Access Journals (Sweden)

    Chin-Guo Kuo

    2016-03-01

    Full Text Available In this investigation, anodic aluminum oxide (AAO with arrayed and regularly arranged nanopores is used as a template in the high-vacuum die casting of molten zinc metal (Zn into the nanopores. The proposed technique yields arrayed Zn nanowires with an aspect ratio of over 600. After annealing, arrayed zinc oxide (ZnO nanowires are obtained. Varying the anodizing time yields AAO templates with thicknesses of approximately 50 μm, 60 μm, and 70 μm that can be used in the fabrication of nanowires of three lengths with high aspect ratios. Experimental results reveal that a longer nanowire generates a greater measured piezoelectric current. The ZnO nanowires that are fabricated using an alumina template are anodized for 7 h and produce higher piezoelectric current of up to 69 pA.

  15. Influence of electrode surface microstructures on the state of short vacuum gaps after interruption of high-frequency currents

    Science.gov (United States)

    Niayesh, Kaveh

    2000-09-01

    In this paper the influences of electrode surface microstructures on the electrical field near the new cathode surface and on the distribution of ion density and velocity in the space-charge region after interruption of high-frequency currents in short vacuum gaps have been studied. To investigate these effects, the equations of conservation of mass and momentum are solved two dimensionally in the space-charge region. The results indicate a considerable increase in ion density at the points with high electrical fields, which results in an enhancement of the electrical field at these points compared with one-dimensional calculations. Considering the calculated electrical field near the cathode surface and the power density deposited into the cathode surface by ions, the initiation of a breakdown during the post arc period under the mechanism of explosive electron emission may be possible.

  16. [Prophylactic Effectiveness of Vacuum-assisted Closure for High-risk Patients Undergoing Cardiovascular Surgery through Median Sternotomy].

    Science.gov (United States)

    Takazawa, Ippei; Misawa, Yoshio; Uesugi, Satoshi; Sugaya, Akira; Akutsu, Hirohiko; Kurumisawa, Souki; Satoh, Hirotaka; Muraoka, Arata; Aizawa, Kei; Ohki, Shinichi; Kawahito, Koji

    2017-08-01

    Vacuum-assisted closure(VAC) therapy is mainly used for tissue defects. VAC therapy can remove exudate that could impair the healing process. We applied VAC therapy in patients considered at high risk of surgical site infection who underwent cardiovascular surgery via standard median sternotomy. Risk factors included advanced heart failure, obesity, diabetes mellitus, steroid administration, immunosuppressant administration, and chronic renal failure, etc. VAC therapy was used in 134 patients. Only 3 of these patients (2.2%) developed surgical site infection caused by Staphylococcus epidermidis;2 patients fully recovered after prolonged VAC therapy for 2 weeks, and the other required an additional sternal fixation after the sternal wires were removed for wound infection control. No patient developed infective mediastinitis. Prophylactic VAC therapy can reduce postoperative wound infection in high risk patients undergoing open heart surgery via full sternotomy.

  17. Vacuum Valve

    CERN Multimedia

    1974-01-01

    This valve was used in the Intersecting Storage Rings (ISR) to protect against the shock waves that would be caused if air were to enter the vacuum tube. Some of the ISR chambers were very fragile, with very thin walls - a design required by physicists on the lookout for new particles.

  18. Thermal noise limit for ultra-high vacuum noncontact atomic force microscopy

    Directory of Open Access Journals (Sweden)

    Jannis Lübbe

    2013-01-01

    Full Text Available The noise of the frequency-shift signal Δf in noncontact atomic force microscopy (NC-AFM consists of cantilever thermal noise, tip–surface-interaction noise and instrumental noise from the detection and signal processing systems. We investigate how the displacement-noise spectral density dz at the input of the frequency demodulator propagates to the frequency-shift-noise spectral density dΔf at the demodulator output in dependence of cantilever properties and settings of the signal processing electronics in the limit of a negligible tip–surface interaction and a measurement under ultrahigh-vacuum conditions. For a quantification of the noise figures, we calibrate the cantilever displacement signal and determine the transfer function of the signal-processing electronics. From the transfer function and the measured dz, we predict dΔf for specific filter settings, a given level of detection-system noise spectral density dzds and the cantilever-thermal-noise spectral density dzth. We find an excellent agreement between the calculated and measured values for dΔf. Furthermore, we demonstrate that thermal noise in dΔf, defining the ultimate limit in NC-AFM signal detection, can be kept low by a proper choice of the cantilever whereby its Q-factor should be given most attention. A system with a low-noise signal detection and a suitable cantilever, operated with appropriate filter and feedback-loop settings allows room temperature NC-AFM measurements at a low thermal-noise limit with a significant bandwidth.

  19. Ultra thin films of gadolinium deposited by evaporation in ultra high vacuum conditions: Composition, growth and morphology

    Energy Technology Data Exchange (ETDEWEB)

    Herrera-Sancho, O.A.; Castro-Gonzalez, D.; Araya-Pochet, J.A. [Centro de Investigacion en Ciencia e Ingenieria de Materiales, Universidad de Costa Rica, 2060 San Pedro, San Jose (Costa Rica); Escuela de Fisica, Universidad de Costa Rica, 2060 San Pedro, San Jose (Costa Rica); Vargas-Castro, W.E., E-mail: william.vargascastro@ucr.ac.cr [Centro de Investigacion en Ciencia e Ingenieria de Materiales, Universidad de Costa Rica, 2060 San Pedro, San Jose (Costa Rica); Escuela de Fisica, Universidad de Costa Rica, 2060 San Pedro, San Jose (Costa Rica)

    2011-02-01

    Ultra-thin gadolinium films with thicknesses between 8 and 101 A were deposited on AT-cut crystalline quartz substrates under ultra high vacuum conditions, and subsequently subjected to composition and morphologic characterization through X-ray photo-spectroscopy analysis and atomic force microscopy. Oxygen contamination is found on the samples, and its amount is estimated in terms of the thickness of an oxygen layer over the gadolinium films after subtracting the contribution to the XPS spectra of the underlying background. Atomic force microscope pictures provide evidence of having metal island films, with two growing regimes: the Volmer-Weber mode for the thinner films considered and the Stranski-Krastanov growing mode for the thicker ones. From evaluation of the sticking coefficient, the shape of the islands is approximated in terms of oblate spheroid caps and variation of the contact angle with film mass thickness is reported.

  20. Growth of high-quality CuInSe sub 2 polycrystalline films by magnetron sputtering and vacuum selenization

    CERN Document Server

    Xie Da Tao; Wang Li; Zhu Feng; Quan Sheng Wen; Meng Tie Jun; Zhang Bao Cheng; Chen J

    2002-01-01

    High-quality CuInSe sub 2 thin films have been prepared using a two stages process. Cu and In were co-deposited onto glass substrates by magnetron sputtering method to produce a predominant Cu sub 1 sub 1 In sub 9 phase. The alloy films were selenised and annealed in vacuum at different temperature in the range of 200-500 degree C using elemental selenium in a closed graphite box. X-ray diffraction and scanning electron microscopy were used to characterize the films. It is found that the polycrystalline and single-phase CuInSe sub 2 films were uniform and densely packed with a grain size of about 3.0 mu m

  1. A surface science compatible epifluorescence microscope for inspection of samples under ultra high vacuum and cryogenic conditions

    Science.gov (United States)

    Marquardt, Christian; Paulheim, Alexander; Rohbohm, Nils; Merkel, Rudolf; Sokolowski, Moritz

    2017-08-01

    We modified an epi-illumination light microscope and mounted it on an ultra high vacuum chamber for investigating samples used in a surface science experiment. For easy access and bake out, all optical components are placed outside the vacuum and the sample is imaged through a glass window. The microscope can be operated in reflection brightfield or epifluorescence mode to image the sample surface or fluorescent dye molecules adsorbed on it. The homemade sample mounting was made compatible for the use under the microscope; sample temperatures as low as 6 K can be achieved. The performance of the microscope is demonstrated on two model samples: Brightfield-images of a well-prepared Ag(100) surface show a macroscopic corrugation of the surface, although low energy electron diffraction data indicate a highly ordered crystalline surface. The surface shows macroscopic protrusions with flat regions, about 20-200 μm in diameter, in between. Fluorescence images of diluted 3,4,9,10-perylene tetracarboxylicacid dianhydride (PTCDA) molecules adsorbed on an ultrathin epitaxial KCl film on the Ag(100) surface show a shading effect at surface protrusions due to an inclined angle of incidence of the PTCDA beam during deposition. For some preparations, the distribution of the fluorescence intensity is inhomogeneous and shows a dense network of bright patches about 5 μm in diameter related to the macroscopic corrugation of the surface. We propose that such a light microscope can aid many surface science experiments, especially those dealing with epitaxial growth or fluorescent materials.

  2. A surface science compatible epifluorescence microscope for inspection of samples under ultra high vacuum and cryogenic conditions.

    Science.gov (United States)

    Marquardt, Christian; Paulheim, Alexander; Rohbohm, Nils; Merkel, Rudolf; Sokolowski, Moritz

    2017-08-01

    We modified an epi-illumination light microscope and mounted it on an ultra high vacuum chamber for investigating samples used in a surface science experiment. For easy access and bake out, all optical components are placed outside the vacuum and the sample is imaged through a glass window. The microscope can be operated in reflection brightfield or epifluorescence mode to image the sample surface or fluorescent dye molecules adsorbed on it. The homemade sample mounting was made compatible for the use under the microscope; sample temperatures as low as 6 K can be achieved. The performance of the microscope is demonstrated on two model samples: Brightfield-images of a well-prepared Ag(100) surface show a macroscopic corrugation of the surface, although low energy electron diffraction data indicate a highly ordered crystalline surface. The surface shows macroscopic protrusions with flat regions, about 20-200 μm in diameter, in between. Fluorescence images of diluted 3,4,9,10-perylene tetracarboxylicacid dianhydride (PTCDA) molecules adsorbed on an ultrathin epitaxial KCl film on the Ag(100) surface show a shading effect at surface protrusions due to an inclined angle of incidence of the PTCDA beam during deposition. For some preparations, the distribution of the fluorescence intensity is inhomogeneous and shows a dense network of bright patches about 5 μm in diameter related to the macroscopic corrugation of the surface. We propose that such a light microscope can aid many surface science experiments, especially those dealing with epitaxial growth or fluorescent materials.

  3. The fabrication of a double-layer atom chip with through silicon vias for an ultra-high-vacuum cell

    Science.gov (United States)

    Chuang, Ho-Chiao; Lin, Yun-Siang; Lin, Yu-Hsin; Huang, Chi-Sheng

    2014-04-01

    This study presents a double-layer atom chip that provides users with increased diversity in the design of the wire patterns and flexibility in the design of the magnetic field. It is more convenient for use in atomic physics experiments. A negative photoresist, SU-8, was used as the insulating layer between the upper and bottom copper wires. The electrical measurement results show that the upper and bottom wires with a width of 100 µm can sustain a 6 A current without burnout. Another focus of this study is the double-layer atom chips integrated with the through silicon via (TSV) technique, and anodically bonded to a Pyrex glass cell, which makes it a desired vacuum chamber for atomic physics experiments. Thus, the bonded glass cell not only significantly reduces the overall size of the ultra-high-vacuum (UHV) chamber but also conducts the high current from the backside to the front side of the atom chip via the TSV under UHV (9.5 × 10-10 Torr). The TSVs with a diameter of 70 µm were etched through by the inductively coupled plasma ion etching and filled by the bottom-up copper electroplating method. During the anodic bonding process, the electroplated copper wires and TSVs on atom chips also need to pass the examination of the required bonding temperature of 250 °C, under an applied voltage of 1000 V. Finally, the UHV test of the double-layer atom chips with TSVs at room temperature can be reached at 9.5 × 10-10 Torr, thus satisfying the requirements of atomic physics experiments under an UHV environment.

  4. Extending the laserspray ionization concept to produce highly charged ions at high vacuum on a time-of-flight mass analyzer.

    Science.gov (United States)

    Trimpin, Sarah; Ren, Yue; Wang, Beixi; Lietz, Christopher B; Richards, Alicia L; Marshall, Darrell D; Inutan, Ellen D

    2011-07-15

    A new matrix compound, 2-nitrophloroglucinol, is reported which not only produces highly charged ions similar to electrospray ionization (ESI) under atmospheric pressure (AP) and intermediate pressure (IP) laserspray ionization (LSI) conditions but also the most highly charged ions so far observed for small proteins in mass spectrometry (MS) under high vacuum (HV) conditions. This new matrix extends the compounds that can successfully be employed as matrixes with LSI, as demonstrated on an LTQ Velos (Thermo) at AP, a matrix-assisted laser desorption/ionization (MALDI)-ion mobility spectrometry (IMS) time-of-flight (TOF) SYNAPT G2 (Waters) at IP, and MALDI-TOF Ultraflex, UltrafleXtreme, and Autoflex Speed (Bruker) mass spectrometers at HV. Measurements show that stable multiple charged molecular ions of proteins are formed under all pressure conditions indicating softer ionization than MALDI, which suffers a high degree of metastable fragmentation when multiply charged ions are produced. An important analytical advantage of this new LSI matrix are the potential for high sensitivity equivalent or better than AP-LSI and vacuum MALDI and the potential for enhanced mass selected fragmentation of the abundant highly charged protein ions. A second new LSI matrix, 4,6-dinitropyrogallol, produces abundant multiply charged ions at AP but not under HV conditions. The differences in these similar compounds ability to produce multiply charged ions under HV conditions is believed to be related to their relative ability to evaporate from charged matrix/analyte clusters.

  5. Fabrication and characterization of free-standing, high-line-density transmission gratings for the vacuum UV to soft X-ray range

    NARCIS (Netherlands)

    Goh, S.J.; Bastiaens, H.J.M.; Vratzov, B.; Huang, Q.; Bijkerk, F.; Boller, K-J.

    2015-01-01

    We present state-of-the-art high resolution transmission gratings, applicable for spectroscopy in the vacuum ultraviolet (VUV) and the soft X-ray (SRX) wavelength range, fabricated with a novel process using ultraviolet based nano imprint lithography (UV-NIL). Free-standing, high-line-density gratin

  6. 75 FR 76019 - Compliance Policy Guide Sec. 390.500 Definition of “High-Voltage Vacuum Switch”-21 CFR 1002.61(a...

    Science.gov (United States)

    2010-12-07

    ... HUMAN SERVICES Food and Drug Administration Compliance Policy Guide Sec. 390.500 Definition of ``High... Administration, HHS. ACTION: Notice; withdrawal. SUMMARY: The Food and Drug Administration (FDA) is announcing the withdrawal of Compliance Policy Guide Sec. 390.500 Definition of ``High-Voltage Vacuum...

  7. Vacuum measurement on vacuum packaged MEMS devices

    Energy Technology Data Exchange (ETDEWEB)

    Gan Zhiyin; Lin Dong; Wang Xuefang; Chenggang; Zhang Honghai; Liu Sheng [Institute of Microsystems and Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China, 430074 (China)

    2007-07-15

    This paper investigates the relationship between the resonance impedance of a tuning fork quartz oscillator and the small size cavity vacuum pressure and develops an on-line vacuum measurement system to track real-time vacuum pressure in MEMS devices. Furthermore, authors completely analyze all facts that affect the resonance impedance. A set of metal vacuum packaged devices have been monitored for more than 10 months using this on-line vacuum measurement system. The results indicate that it is very critical to investigate vacuum packaging processes, reliability and durability of the vacuum devices by using this on-line vacuum measurement system.

  8. New Vacuum Solar Telescope

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    With its pure aperture up to 985mm, the New Vacuum Solar Telescope of China (NVST) has become the world's biggest vacuum solar telescope. The main science task of NVST is the high-resolution observation of photosphere and chromosphere including their fine structure of magnetic field on the sun. The NVST was equipped with many new technologies and powerful instruments, such as an adaptive optical system, a polarization analyzer, two vertical spectrographs, a high-resolution image system and a very narrow Ha filter (0.125A).

  9. Superoleophobicity under vacuum

    Science.gov (United States)

    Liu, Xinjie; Wang, Xiaolong; Liang, Yongmin; Bell, Steven E. J.; Liu, Weimin; Zhou, Feng

    2011-05-01

    By using superoleophobic alumina and low vapor pressure oils we have been able to study wetting behavior at high vacuum. Here, we show that a superoleophobic state can exist for some probe liquids, even under high vacuum. However, with other liquids the surfaces are only superoloephobic because air is trapped beneath the droplet and the contact angle decreases dramatically (150°-120°) if this air is removed. These observations open up the possibility of designing materials which fully exploit the potential of physically trapped air to achieve extreme oleophobicity and/or hydrophobicity.

  10. Effects of vacuum thermal cycling on mechanical and physical properties of high performance carbon/bismaleimide composite

    Energy Technology Data Exchange (ETDEWEB)

    Yu Qi [State Key Laboratory of Fine Chemicals and School of Chemical Engineering, Dalian University of Technology, Dalian Liaoning 116024 (China); Liaoning Key Laboratory of Advanced Polymer Matrix Composites and College of Aerospace Engineering, Shenyang Aerospace University, Shenyang Liaoning 110136 (China); Chen Ping, E-mail: chenping_898@126.com [State Key Laboratory of Fine Chemicals and School of Chemical Engineering, Dalian University of Technology, Dalian Liaoning 116024 (China) and Liaoning Key Laboratory of Advanced Polymer Matrix Composites and College of Aerospace Engineering, Shenyang Aerospace University, Shenyang Liaoning 110136 (China); Gao Yu; Mu Jujie; Chen Yongwu; Lu Chun [Liaoning Key Laboratory of Advanced Polymer Matrix Composites and College of Aerospace Engineering, Shenyang Aerospace University, Shenyang Liaoning 110136 (China); Liu Dong [State Key Laboratory of Fine Chemicals and School of Chemical Engineering, Dalian University of Technology, Dalian Liaoning 116024 (China)

    2011-11-01

    Highlights: {yields} The level of cross-links was improved to a certain extent. {yields} The thermal stability was firstly improved and then decreased. {yields} The transverse and longitudinal CTE were both determined by the degree of interfacial debonding. {yields} The mass loss ratio increases firstly and then reaches a plateau value. {yields} The surface morphology was altered and the surface roughness increased firstly and then decreased. {yields} The transverse tensile strength was reduced. {yields} The flexural strength increased firstly and then decreased to a plateau value. {yields} The ILSS increased firstly and then decreased to a plateau value. - Abstract: The aim of this article was to investigate the effects of vacuum thermal cycling on mechanical and physical properties of high performance carbon/bismaleimide (BMI) composites used in aerospace. The changes in dynamic mechanical properties and thermal stability were characterized by dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA), respectively. The changes in linear coefficient of thermal expansion (CTE) were measured in directions perpendicular and parallel to the fiber direction, respectively. The outgassing behavior of the composites were examined. The evolution of surface morphology and surface roughness were observed by atomic force microscopy (AFM). Changes in mechanical properties including transverse tensile strength, flexural strength and interlaminar shear strength (ILSS) were measured. The results indicated that the vacuum thermal cycling could improve the crosslinking degree and the thermal stability of resin matrix to a certain extent, and induce matrix outgassing and thermal stress, thereby leading to the mass loss and the interfacial debonding of the composite. The degradation in transverse tensile strength was caused by joint effects of the matrix outgassing and the interfacial debonding, while the changes in flexural strength and ILSS were affected by a competing

  11. Gases and vacua handbook of vacuum physics

    CERN Document Server

    Beck, A H

    2013-01-01

    Handbook of Vacuum Physics, Volume 1: Gases and Vacua provides information on the many aspects of vacuum technology, from material on the quantum theoretical aspects of the complex semi-conductors used for thermionic and photo-electric emission to data on the performance of commercially available pumps, gauges, and high-vacuum materials. The handbook satisfies the need of workers using vacuum apparatuses or works on the diverse applications of high-vacuum technology in research and industry. The book is a compilation of long articles prepared by experts in vacuum technology. Sufficient theoret

  12. High-precision potassium measurements using laser-induced breakdown spectroscopy under high vacuum conditions for in situ K–Ar dating of planetary surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yuichiro, E-mail: cho@rikkyo.ac.jp [Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501 (Japan); Department of Complexity Science and Engineering, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Sugita, Seiji [Department of Complexity Science and Engineering, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Kameda, Shingo [Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501 (Japan); Miura, Yayoi N. [Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-0032 (Japan); Ishibashi, Ko; Ohno, Sohsuke [Planetary Exploration Research Center, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba 275-0016 (Japan); Kamata, Shunichi [Hokkaido University Graduate School of Science, 8-2-10 Kita-10 Nishi-8, Kita-ku, Sapporo, Hokkaido 060-0810 (Japan); Arai, Tomoko [Planetary Exploration Research Center, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba 275-0016 (Japan); Morota, Tomokatsu [Department of Earth and Environmental Sciences, Nagoya University, Furo Chikusa, Nagoya, Aichi 464-8601 (Japan); Namiki, Noriyuki [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Matsui, Takafumi [Planetary Exploration Research Center, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba 275-0016 (Japan)

    2015-04-01

    We conducted a series of laser induced breakdown spectroscopy (LIBS) experiments for K measurements under high vacuum conditions (10{sup -6} Pa) for the purpose of developing in-situ isochron type K–Ar dating instruments for planetary missions. Unlike whole rock measurement methods, isochron measurements require LIBS experiments in a vacuum chamber because simultaneous Ar isotopic measurements are necessary. However, detailed examination of detection limits and accuracy of this method at low pressures has not been examined extensively before. In this study, the capability of K measurements under high vacuum conditions was examined using LIBS. A compact Czerny-Turner type spectrometer equipped with a charge-coupled device (CCD) as a detector was employed. Twenty-three geologic standard samples were measured using the LIBS method. The second strongest K emission line at 769.89 nm was used for calibration because the strongest emission line at 766.49 nm may suffer from strong interference from another emission line. A calibration curve was constructed for K using internal normalization with the oxygen line at 777 nm and well fitted by a power-law function. Based on the prediction band method, the detection limit and the quantitation limit were estimated to be 300 and 800 ppm, respectively. The 1σ relative uncertainty of the K calibration was 20% for 1 wt.% K{sub 2}O and 40% for 3000 ppm K{sub 2}O. If the amount of Ar is measured with 15% error for the 3.5 billion years rocks containing 1 and 0.3 wt.% K{sub 2}O, the K–Ar ages would be determined with 10% and 20% 1σ errors, respectively. This level of precision will significantly improve the current Martian chronology, which has uncertainty about a factor of two to four. These results indicate that the concentration of K can be measured quantitatively under high vacuum conditions using a combination of instruments that have previously been carried in planetary missions, which suggests the viability of building in

  13. R&D ERL: Vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Mapes, M.; Smart, L.; Weiss, D.; Steszyn, A.; Todd, R.

    2010-01-01

    The ERL Vacuum systems are depicted in a figure. ERL has eight vacuum volumes with various sets of requirements. A summary of vacuum related requirements is provided in a table. Five of the eight volumes comprise the electron beamline. They are the 5-cell Superconducting RF Cavity, Superconducting e-gun, injection, loop and beam dump. Two vacuum regions are the individual cryostats insulating the 5-cell Superconducting RF Cavity and the Superconducting e-gun structures. The last ERL vacuum volume not shown in the schematic is the laser transport line. The beamline vacuum regions are separated by electropneumatic gate valves. The beam dump is common with loop beamline but is considered a separate volume due to geometry and requirements. Vacuum in the 5-cell SRF cavity is maintained in the {approx}10{sup -9} torr range at room temperature by two 20 l/s ion pumps and in the e-gun SRF cavity by one 60 l/s ion pump. Vacuum in the SRF cavities operated at 2{sup o}K is reduced to low 10{sup -11} torr via cryopumping of the cavity walls. The cathode of the e-gun must be protected from poisoning, which can occur if vacuum adjacent to the e-gun in the injection line exceeds 10-11 torr range in the injection warm beamline near the e-gun exit. The vacuum requirements for beam operation in the loop and beam dump are 10-9 torr range. The beamlines are evacuated from atmospheric pressure to high vacuum level with a particulate free, oil free turbomolecular pumping cart. 25 l/s shielded ion pumps distributed throughout the beamlines maintain the vacuum requirement. Due to the more demanding vacuum requirement of the injection beamline proximate to the e-gun, a vacuum bakeout of the injection beamline is required. In addition, two 200 l/s diode ion pumps and supplemental pumping provided by titanium sublimation pumps are installed in the injection line just beyond the exit of the e-gun. Due to expected gas load a similar pumping arrangement is planned for the beam dump. The

  14. Development of a high-speed vacuum ultraviolet (VUV) imaging system for the Experimental Advanced Superconducting Tokamak

    Science.gov (United States)

    Zhou, Fan; Ming, Tingfeng; Wang, Yumin; Wang, Zhijun; Long, Feifei; Zhuang, Qing; Li, Guoqiang; Liang, Yunfeng; Gao, Xiang

    2017-07-01

    A high-speed vacuum ultraviolet (VUV) imaging system for edge plasma studies is being developed on the Experimental Advanced Superconducting Tokamak (EAST). Its key optics is composed of an inverse type of Schwarzschild telescope made of a set of Mo/Si multilayer mirrors, a micro-channel plate (MCP) equipped with a P47 phosphor screen and a high-speed camera with CMOS sensors. In order to remove the contribution from low-energy photons, a Zr filter is installed in front of the MCP detector. With this optics, VUV photons with a wavelength of 13.5 nm, which mainly come from the line emission from intrinsic carbon (C vi: n = 4-2 transition) or the Ly-α line emission from injected Li iii on the EAST, can be selectively measured two-dimensionally with both high temporal and spatial resolutions. At present, this system is installed to view the plasma from the low field side in a horizontal port in the EAST. It has been operated routinely during the 2016 EAST experiment campaign, and the first result is shown in this work. To roughly evaluate the system performance, synthetic images are created. And it indicates that this system mainly measures the edge localized emissions by comparing the synthetic images and experimental data.

  15. Baryogenesis in false vacuum

    CERN Document Server

    Hamada, Yuta

    2016-01-01

    The null result in the LHC may indicate that the standard model is not drastically modified up to very high scale such as the GUT/string scale. Having this in the mind, we suggest a novel leptogenesis scenario realized in the false vacuum of the Higgs field. If the Higgs field develops the large vacuum expectation value in the early universe, the lepton number violating process is enhanced, which we use for baryogenesis. To demonstrate the scenario, several models are discussed. For example, we show that the observed baryon asymmetry is successfully generated in the standard model with a second Higgs doublet and a singlet scalar.

  16. 1.5 kW high-peak-power vacuum ultraviolet flash lamp using a pulsed silent discharge of krypton gas

    Science.gov (United States)

    Kawanaka, J.; Shirai, T.; Kubodera, S.; Sasaki, W.

    2001-12-01

    A 1.5 kW high-peak-power discharge lamp with short emission duration of 140 ns has been developed in the vacuum ultraviolet spectral region. Our numerical calculation ensured that the peak emission at 147 nm was due to singlet excimers (1Σ), which were mainly produced via electron-collisional mixing of triplet excimers (3Σ).

  17. Effects of Precipitates in Cu upon Impact Fracture : An Ultra-High-Vacuum Study with Local Probe Scanning Auger/Electron Microscopy

    NARCIS (Netherlands)

    Agterveld, D.T.L. van; Palasantzas, G.; Hosson, J.Th.M. De

    2000-01-01

    In situ fracture under ultra-high vacuum (UHV) conditions of copper-alloys containing copper sulfide precipitates exhibits areas in the form of pits. The wide variety of morphologies depends significantly on the size of the existing precipitate. For large precipitates, the fractured surface reveals

  18. Molecular Surface Chemistry by Metal Single Crystals and Nanoparticles from Vacuum to High Pressure.

    Energy Technology Data Exchange (ETDEWEB)

    Somorjai, Gabor A.; Park, Jeong Y.

    2008-04-05

    Model systems for studying molecular surface chemistry have evolved from single crystal surfaces at low pressure to colloidal nanoparticles at high pressure. Low pressure surface structure studies of platinum single crystals using molecular beam surface scattering and low energy electron diffraction techniques probe the unique activity of defects, steps and kinks at the surface for dissociation reactions (H-H, C-H, C-C, O{double_bond}O bonds). High-pressure investigations of platinum single crystals using sum frequency generation vibrational spectroscopy have revealed the presence and the nature of reaction intermediates. High pressure scanning tunneling microscopy of platinum single crystal surfaces showed adsorbate mobility during a catalytic reaction. Nanoparticle systems are used to determine the role of metal-oxide interfaces, site blocking and the role of surface structures in reactive surface chemistry. The size, shape and composition of nanoparticles play important roles in determining reaction activity and selectivity.

  19. High-reflectivity multilayer mirrors for a vacuum-ultraviolet interval of 35-50nm.

    Science.gov (United States)

    Uspenskii, Y A; Levashov, V E; Vinogradov, A V; Fedorenko, A I; Kondratenko, V V; Pershin, Y P; Zubarev, E N; Fedotov, V Y

    1998-05-15

    Sc-Si multilayers are suggested as high-reflectivity coatings for a VUV interval of 35-50 nm. Fabricated mirrors show normal-incidence reflectivity of 30-54%, which is high enough for effective manipulation of the beams of compact-discharge, laser-driven x-ray lasers. The values obtained are not, however, limits for Sc-Si coatings. Theoretical estimations as well as electron microscopy studies of Sc-Si interfaces indicate a large potential for a further increase in their reflectivity.

  20. High-Efficiency Solar Thermal Vacuum Demonstration Completed for Refractive Secondary Concentrator

    Science.gov (United States)

    Wong, Wayne A.

    2001-01-01

    Common to many of the space applications that utilize solar thermal energy--such as electric power conversion, thermal propulsion, and furnaces--is a need for highly efficient, solar concentration systems. An effort is underway at the NASA Glenn Research Center to develop the refractive secondary concentrator, which uses refraction and total internal reflection to efficiently concentrate and direct solar energy. When used in combination with advanced lightweight primary concentrators, the refractive secondary concentrator enables very high system concentration ratios (10,000 to 1) and very high temperatures (>2000 K). The innovative refractive secondary concentrator offers significant advantages over all other types of secondary concentrators. The refractive secondary offers the highest throughput efficiency, provides for flux tailoring, requires no active cooling, relaxes the pointing and tracking requirements of the primary concentrator, and enables very high system concentration ratios. This technology has broad applicability to any system that requires the conversion of solar energy to heat. Glenn initiated the development of the refractive secondary concentrator in support of Shooting Star, a solar thermal propulsion flight experiment, and continued the development in support of Space Solar Power.

  1. Complete elution of vacuum gas oil resins by comprehensive high-temperature two-dimensional gas chromatography.

    Science.gov (United States)

    Boursier, Laure; Souchon, Vincent; Dartiguelongue, Cyril; Ponthus, Jérémie; Courtiade, Marion; Thiébaut, Didier

    2013-03-08

    The development of efficient conversion processes requires extended knowledge on vacuum gas oils (VGOs). Among these processes, hydrocracking is certainly one of the best suited to meet the increasing demand on high quality diesel fuels. Most of refractory and inhibiting compounds towards hydrocracking and especially nitrogen containing compounds are contained in a fraction of the VGO called the resin fraction, which corresponds to the most polar fraction of a VGO obtained by liquid chromatography (LC) fractionation on a silica column. However, the lack of resolution observed through existing analytical methods does not allow a detailed characterization of these fractions. A recent study showed that comprehensive high temperature two-dimensional gas chromatography (HT-GC×GC) methods could be optimized in order to elute heavy compounds. This method was implemented for the analysis of VGO resin fractions and complete elution was reached. Firstly, the method was validated through repeatability, accuracy, linearity and response factors calculations. Four VGO resin fractions were analyzed and their HT-GC×GC simulated distillation curves were compared to their GC simulated distillation (GC-SimDist) curves. This comparison showed that the method allows complete elution of most of the analyzed VGO resin fractions. However, a detailed characterization of these fractions is not yet obtained due to the very large number of heteroatomic and aromatic species that a flame ionization detector can detect. Current work aims at increasing the selectivity of GC×GC by using heteroatom selective detectors in order to improve the characterization of such products.

  2. Sensitivity to Dark Energy candidates by searching for four-wave mixing of high-intensity lasers in the vacuum

    CERN Document Server

    Homma, Kensuke

    2012-01-01

    Theoretical challenges to understand Dark Matter and Dark Energy suggest the existence of low-mass and weakly coupling fields in the universe. The quasi-parallel photon-photon collision system (QPS) can provide chances to probe the resonant production of these light dark fields and the induced decay by the coherent nature of laser fields simultaneously. By focusing high-intensity lasers with different colors in the vacuum, new colors emerge as the signature of the interaction. Because four photons in the initial and final states interplay via the dark field exchange, this process is analogous to four-wave mixing in quantum optics, where the frequency sum and difference among the incident three waves generate the fourth wave with a new frequency via the nonlinear property of crystals. The interaction rate of the four-wave mixing process has the cubic dependence on the intensity of each wave. Therefore, if high-intensity laser fields are given, the sensitivity to the weakly coupling of dark fields to photons ra...

  3. Vacuum ultra-violet damage and damage mitigation for plasma processing of highly porous organosilicate glass dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Marneffe, J.-F. de, E-mail: marneffe@imec.be; Lukaszewicz, M.; Porter, S. B.; Vajda, F.; Rutigliani, V.; Verdonck, P.; Baklanov, M. R. [IMEC v.z.w., 3001 Leuven (Belgium); Zhang, L.; Heyne, M.; El Otell, Z.; Krishtab, M. [IMEC v.z.w., 3001 Leuven (Belgium); Department of Chemistry, KULeuven, 3001 Leuven (Belgium); Goodyear, A.; Cooke, M. [Oxford Instruments Plasma Technology, BS49 4AP Bristol (United Kingdom)

    2015-10-07

    Porous organosilicate glass thin films, with k-value 2.0, were exposed to 147 nm vacuum ultra-violet (VUV) photons emitted in a Xenon capacitive coupled plasma discharge. Strong methyl bond depletion was observed, concomitant with a significant increase of the bulk dielectric constant. This indicates that, besides reactive radical diffusion, photons emitted during plasma processing do impede dielectric properties and therefore need to be tackled appropriately during patterning and integration. The detrimental effect of VUV irradiation can be partly suppressed by stuffing the low-k porous matrix with proper sacrificial polymers showing high VUV absorption together with good thermal and VUV stability. In addition, the choice of an appropriate hard-mask, showing high VUV absorption, can minimize VUV damage. Particular processing conditions allow to minimize the fluence of photons to the substrate and lead to negligible VUV damage. For patterned structures, in order to reduce VUV damage in the bulk and on feature sidewalls, the combination of both pore stuffing/material densification and absorbing hard-mask is recommended, and/or the use of low VUV-emitting plasma discharge.

  4. A proposal for testing subcritical vacuum pair production with high power lasers

    Science.gov (United States)

    Gregori, G.; Blaschke, D. B.; Rajeev, P. P.; Chen, H.; Clarke, R. J.; Huffman, T.; Murphy, C. D.; Prozorkevich, A. V.; Roberts, C. D.; Röpke, G.; Schmidt, S. M.; Smolyansky, S. A.; Wilks, S.; Bingham, R.

    2010-06-01

    We present a proposal for testing the prediction of non-equilibrium quantum field theory below the Schwinger limit. The proposed experiments should be able to detect a measurable number of gamma rays resulting from the annihilation of pairs in the focal spot of two opposing high-intensity laser beams. We discuss the dependence of the expected number of gamma rays with the laser parameters and compare with the estimated background level of gamma hits for realistic laser conditions.

  5. A proposal for testing subcritical vacuum pair production with high power lasers

    CERN Document Server

    Gregori, G; Rajeev, P P; Chen, H; Clarke, R J; Huffman, T; Murphy, C D; Prozorkevich, A V; Roberts, C D; Röpke, G; Schmidt, S M; Smolyansky, S A; Wilks, S; Bingham, R; 10.1016/j.hedp.2009.11.001

    2010-01-01

    We present a proposal for testing the prediction of non-equilibrium quantum field theory below the Schwinger limit. The proposed experiments should be able to detect a measurable number of gamma rays resulting from the annihilation of pairs in the focal spot of two opposing high intensity laser beams. We discuss the dependence of the expected number of gamma rays with the laser parameters and compare with the estimated background level of gamma hits for realistic laser conditions.

  6. A proposal for testing subcritical vacuum pair production with high power lasers.

    Energy Technology Data Exchange (ETDEWEB)

    Gregori, G.; Blaschke, D. B.; Rajeev, P. P.; Chen, H.; Clarke, R. J.; Huffman, T.; Murphy, C. D.; Prozorkevich, A. V.; Roberts, C. D.; Ropke, G.; Schmidt, S. M.; Smolyansky, S. A.; Wilks, S.; Bingham, R.; Physics; Univ. of Oxford; Rutherford Appleton Lab.; Univ. of Wroclaw; Joint Inst. for Nuclear Research; LLNL; Saratov State Univ.; Univ. Rostock; Technische Univ. Dortmund; Forschungszentrum Julich GmbH

    2009-01-01

    We present a proposal for testing the prediction of non-equilibrium quantum field theory below the Schwinger limit. The proposed experiments should be able to detect a measurable number of gamma rays resulting from the annihilation of pairs in the focal spot of two opposing high-intensity laser beams. We discuss the dependence of the expected number of gamma rays with the laser parameters and compare with the estimated background level of gamma hits for realistic laser conditions.

  7. 大型高真空容器的气体负荷分析%Gas load analysis of large-scale high vacuum vessel

    Institute of Scientific and Technical Information of China (English)

    陆长胜; 于文泉; 黄金祥; 陆艳君; 岳向吉; 巴德纯

    2014-01-01

    With the improvement of science and technology , the development of some vacuum equipments goes toward large scale and high vacuum . Analysis shows that material degassing and gas leakage are the main gas load of large-scale high vacuum vessels . In order to enhance the technical level of large high-vacuum equipments , degassing and leakage should be given more attention in the design of chamber and sealing structure , leak detection design and technological analysis for manufacturing process .%随着科学技术的进步,某些用途的真空装置向大型化、高真空度的方向发展。分析表明材料出气和漏气是大型高真空容器的主要气体负荷,在容器及密封结构设计、检漏设计、制造工艺技术分析中应重点研究,以提高大型高真空装备的技术水平。

  8. New Applications of Scanning Tunneling Microscopy in Air, Liquids, and Ultra-High Vacuum

    Science.gov (United States)

    Dovek, Moris Musa

    Scanning tunneling microscopy (STM) offers a wide range of applications besides being a high resolution tool for atomic scale surface structure determination. We present three applications that are of particular relevance to integrated circuit fabrication: molecular imaging of ultrathin resists, nanometer scale lithography, and epitaxial growth characterization on an atomically flat substrate. The use of thin organic films as ultrathin resists for nanometer scale fabrication and information recording requires an understanding of their microstructure. We have used the Langmuir-Blodgett technique to prepare and the STM to study monolayer and submonolayer films of poly(octadecylacrylate) (PODA) and poly(methylmethacrylate) (PMMA) on graphite. One striking feature was the degree of order observed; a second was the morphological differences between films of submonolayer thickness and those of at least one monolayer. We were also able to locally modify and apparently cut through the polymer fibrils by pulsing the gap voltage in excess of 4 V. Nanometer-scale surface modification has important potential applications in areas such as high resolution lithography for solid-state devices or high density data storage. The STM can be used for surface modification by either mechanical indentation of the surface with the very sharp tip or by applying short voltage or current pulses across the tunnel junction. We review some of the mechanical writing techniques on Au(111), which render depressions of approximately 100 A in diameter. We also introduce a technique for writing permanent features on graphite of 40 A average and 20 A minimum diameter with an average resolvable spacing of 60 A. We found the reliability of the writing process on graphite to depend strongly on the presence of water vapor. STM can also be used to analyze epitaxial growth on an atomic scale, a resolution range not available to SEM, HRTEM, and REM, which have so far been the only tools used to verify

  9. Reduction of Listeria innocua contamination in vacuum-packaged dry-cured Italian pork products after high hydrostatic pressure treatment

    Directory of Open Access Journals (Sweden)

    Giuseppe Merialdi

    2015-06-01

    Full Text Available The present work aims to present the results of the application of a treatment with high hydrostatic pressure (HHP on Italian fermented and dry-cured pork products. The products used in this study were portioned cured ham, portioned bacon and salami, vacuumpackaged and produced by a single processing company. Two studies were conducted on a single batch of the three products by means of an artificial contamination with Listeria innocua as a surrogate of L. monocytogenes. In the first trial a superficial contamination was obtained by immersion for 3 min in the culture broth with a concentration of approximately 9 log cfu/mL. At the end of the inoculum step, the pieces were dred at room temperature and vacuum packaged. In the second trial 50 kg of minced pork meat were contaminated before production of salami. In both cases the inoculum contained 5 strains of L. innocua. Subsequently, in both trials, 10 samples were randomly divided into two groups of 5 pieces each: i TH group, samples treated with HHP; ii group C, control samples, not subjected to any treatment. All samples were stored at refrigeration temperature at the end of HHP treatments (if applied, and analyzed for the determination of the surface (1st trial and deep (2nd trial quantitative contamination of L. innocua. pH and aW were also determined on 3 pieces of each products belonging to group C. The difference between the medians of the log cfu/cm2 or g established between controls and treated were compared using the non-parametric test (Kruskal-Wallis test with P<0.01. In all products and in both trials the level of contamination detected in treatment groups was always significantly lower than in controls (P<0.01. In particular, in vacuum-packaged ham, bacon and salami viability logarithmic viability reductions equal to -2.29, -2.54 and -2.51 were observed, respectively. This study aimed to evaluate a not-thermal treatment on Italian cured or fermented pork products. The results of

  10. Design and initial characterization of a compact, ultra high vacuum compatible, low frequency, tilt accelerometer

    Science.gov (United States)

    O'Toole, A.; Peña Arellano, F. E.; Rodionov, A. V.; Shaner, M.; Sobacchi, E.; Dergachev, V.; DeSalvo, R.; Asadoor, M.; Bhawal, A.; Gong, P.; Kim, C.; Lottarini, A.; Minenkov, Y.; Murphy, C.

    2014-07-01

    A compact tilt accelerometer with high sensitivity at low frequency was designed to provide low frequency corrections for the feedback signal of the Advanced Laser Interferometer Gravitational Wave Observatory active seismic attenuation system. It has been developed using a Tungsten Carbide ceramic knife-edge hinge designed to avoid the mechanical 1/f noise believed to be intrinsic in polycrystalline metallic flexures. Design and construction details are presented; prototype data acquisition and control limitations are discussed. The instrument's characterization reported here shows that the hinge is compatible with being metal-hysteresis-free, and therefore also free of the 1/f noise generated by the dislocation Self-Organized Criticality in the metal. A tiltmeter of this kind will be effective to separate the ground tilt component from the signal of horizontal low frequency seismometers, and to correct the ill effects of microseismic tilt in advanced seismic attenuation systems.

  11. Electrical and structural R&D activities on high voltage dc solid insulator in vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Pilan, N., E-mail: nicola.pilan@igi.cnr.it [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); Marcuzzi, D.; Rizzolo, A.; Grando, L.; Gambetta, G. [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); Rosa, S. Dalla [Umicore – Italbras S.p.A., Strada del Balsego, n.6, 36100 Vicenza (Italy); Kraemer, V.; Quirmbach, T. [FRIATEC Ceramics Division, Steinzeugstrasse 50, 68229 Mannheim (Germany); Chitarin, G. [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); Gobbo, R.; Pesavento, G. [DII, Università di Padova, v. Gradenigo 6/A, I-35131 Padova (Italy); De Lorenzi, A.; Lotto, L.; Rizzieri, R.; Fincato, M.; Romanato, L.; Trevisan, L.; Cervaro, V.; Franchin, L. [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy)

    2015-10-15

    Highlights: • A thorough R&D activity on the MITICA post insulator prototypes is being carried out. • The design has been numerically verified considering both mechanical and electrical aspects. • Experimental validation has been started, with positive results in both involved fields. • Alternative design solutions thickness have been proposed and successfully tested. - Abstract: This paper describes the R&D work performed in support of the design of the alumina insulators for the MITICA Neutral Beam Injector. The ceramic insulators are critical elements, both from the structural and electrical point of view, of the 1 MV electrostatic accelerator of the MITICA injector, as they are required to sustain both the mechanical loads due to the cantilevered weight of the ion source and the high electric field between the accelerator grids. This paper presents the results of numerical simulations and experimental tests on prototypes that have been carried out to validate the insulator design under realistic operating conditions.

  12. Experimental study of DC vacuum breakdown and application to high-gradient accelerating structures for CLIC

    CERN Document Server

    Shipman, Nicholas; Jones, Roger

    2016-01-01

    The compact linear collider (CLIC) is a leading candidate for the next generation high energy linear collider. As any breakdown would result in a partial or full loss of luminosity for the pulse in which it occurs, obtaining a low breakdown rate in CLIC accelerating structures is a critical requirement for the successful operation of the proposed collider. This thesis presents investigations into the breakdown phenomenon primarily in the low breakdown rate regime of interest to CLIC, performed using the CERN DC spark systems between 2011 and 2014. The design, construction and commissioning of several new pieces of hardware, as well as the development of improved techniques to measuring the inter-electrode gap distance are detailed. These hardware improvements were fundamental in enabling the exciting new experiments mentioned below, which in turn have provided significant additional insight into the phenomenon of breakdown. Experiments were performed to measure fundamental parameters of individual breakdowns...

  13. Design and initial characterization of a compact, ultra high vacuum compatible, low frequency, tilt accelerometer

    Energy Technology Data Exchange (ETDEWEB)

    O’Toole, A., E-mail: amandajotoole@gmail.com, E-mail: riccardo.desalvo@gmail.com [Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 405 Hilgard Ave, Los Angeles, California 90095 (United States); Peña Arellano, F. E. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Rodionov, A. V.; Kim, C. [California Institute of Technology, Pasadena, California 91125 (United States); Shaner, M.; Asadoor, M. [Mayfield Senior School, 500 Bellefontaine Street Pasadena, California 91105 (United States); Sobacchi, E. [Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa (Italy); Dergachev, V.; DeSalvo, R., E-mail: amandajotoole@gmail.com, E-mail: riccardo.desalvo@gmail.com [LIGO Laboratory, California Institute of Technology, MS 100-36, Pasadena, California 91125 (United States); Bhawal, A. [Arcadia High School, 180 Campus Drive, Arcadia, California 91007 (United States); Gong, P. [Department of Precision Instrument, Tsinghua University, Beijing 100084 (China); Lottarini, A. [Department of Computer Science, University of Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Minenkov, Y. [Sezione INFN Tor Vergata, via della Ricerca Scientfica 1, 00133 Roma (Italy); Murphy, C. [School of Physics, The University of Western Australia, 35 Stirling Highway, Crawley, Perth, Western Australia 6009 (Australia)

    2014-07-15

    A compact tilt accelerometer with high sensitivity at low frequency was designed to provide low frequency corrections for the feedback signal of the Advanced Laser Interferometer Gravitational Wave Observatory active seismic attenuation system. It has been developed using a Tungsten Carbide ceramic knife-edge hinge designed to avoid the mechanical 1/f noise believed to be intrinsic in polycrystalline metallic flexures. Design and construction details are presented; prototype data acquisition and control limitations are discussed. The instrument's characterization reported here shows that the hinge is compatible with being metal-hysteresis-free, and therefore also free of the 1/f noise generated by the dislocation Self-Organized Criticality in the metal. A tiltmeter of this kind will be effective to separate the ground tilt component from the signal of horizontal low frequency seismometers, and to correct the ill effects of microseismic tilt in advanced seismic attenuation systems.

  14. Preparation and thermal stability on non-vacuum high temperature solar selective absorbing coatings

    Institute of Scientific and Technical Information of China (English)

    HAO Lei; WANG ShuMao; JIANG LiJun; LIU XiaoPeng; LI HuaLing; LI ZhiNian

    2009-01-01

    Spectrally selective TiAI/TiAIN/TiAION/TiAIO coating was deposited on stainless steel and copper sub-strates using a multi-arc ion plating system.The structure,morphology,optical reflectance and elec-trical resistivity were investigated by X-ray diffraction (XRD),scanning electron microscopy (SEM),spectrophotometer and four-point probe meter,respectively.The results show that the coating exhibits high absorptance (-0.9) and low emittance (0.09-0.19).The coating remains stable in air up to 650℃ for 1h.These properties are of extraordinary interest in solar thermal power generations and energy saving buildings.

  15. Impact of high oxygen and vacuum retail ready packaging formats on lamb loin and topside eating quality.

    Science.gov (United States)

    Frank, Damian Conrad; Geesink, Geert; Alvarenga, Tharcilla I R C; Polkinghorne, Rod; Stark, Janet; Lee, Michael; Warner, Robyn

    2017-01-01

    Lamb steaks from semimembranosus (SM) and longissimus thoracis et lumborum (LTL) muscles were allocated to three different packaging treatments - Darfresh® vacuum skin packaging (VSP), Darfresh® Bloom packaging (80% O2:20% CO2; Hi-Ox-DB) or high oxygen modified atmosphere packaging (80% O2:20% CO2; Hi-Ox-MAP) - and stored in simulated retail display for 5 or 10days and then subjected to consumer sensory and chemical analyses. Hi-Ox-MAP and Hi-Ox-DB samples had lower tenderness, flavor, juiciness and overall liking scores and higher TBARS values, compared to VSP. Hi-Ox-MAP samples deteriorated in juiciness and flavor between 5 and 10days. Hi-Ox-MAP LTL samples had a lower myofibrillar fragmentation index, consistent with reduced proteolysis, although desmin proteolysis and desmin and troponin-T cross-linking were not influenced by packaging. The LTL exhibited greater desmin degradation and reduced desmin cross-linking relative to the SM, supporting the higher tenderness scores in this muscle. Direct packaging of lamb into retail ready VSP may provide the sheepmeat industry with greater flexibility while increasing consumer satisfaction.

  16. Improved ion transmission from atmospheric pressure to high vacuum using a multicapillary inlet and electrodynamic ion funnel interface

    Science.gov (United States)

    Kim; Udseth; Smith

    2000-10-15

    A heated multicapillary inlet and ion funnel interface was developed to couple an electrospray ionization (ESI) source to a high-vacuum stage for obtaining improved sensitivity in mass spectrometric applications. The inlet was constructed from an array of seven thin-wall stainless steel tubes soldered into a central hole of a cylindrical heating block. An electrodynamic ion funnel was used in the interface region to more effectively capture, focus, and transmit ions from the multicapillary inlet. The interface of seven capillary inlets with the ion funnel showed more than 7 times higher transmission efficiency compared to that of a single capillary inlet with the ion funnel and a 23-fold greater transmission efficiency than could be obtained using the standard orifice-skimmer interface of a triple-quadrupole MS. The multiple-capillary inlet and ion funnel interface showed an overall 10% ion transmission efficiency and approximately 3-4% overall detection efficiency of ions from solution based (i.e., prior to electrospray). The improved performance was achieved under conditions where ESI operation is robust and results in a significant increase in dynamic range.

  17. Temporal distribution of electron and ion emission caused by laser excitation of optical surfaces in ultra-high vacuum

    Science.gov (United States)

    Siekhaus, W. J.; Chase, L. L.; Milam, D.

    1986-05-01

    We have measured electron and ion emission under high vacuum conditions from several semiconductor and insulator surfaces excited by the first and third harmonics of a 1.06 micron Nd laser. The dependence of this emission on laser fluence and wavelength is consistent with a multiphoton excitation process. The dependence on laser pulse length implies, however, that other processes, either diffusive, thermal or thermomechanical, are also involved. Additional information is provided by the temporal and spatial distribution of the charge emission. The most extensive results have been obtained with single crystals of ZnS, for which nearly equal magnitudes of negative and positive charge emission are observed. The results suggest the possibility that the observed charge emission results primarily from the ejection of neutral atoms and molecules from the surface, followed by selective multiphoton ionization of one or more of the neutral species. The irreversible surface modification implied by the observed emission may be the precursor to observable surface damage. Detailed studies of the properties of the emitted particles may be very useful in developing a basic understanding of the damage mechanisms.

  18. Ion-ion coincidence imaging at high event rate using an in-vacuum pixel detector

    Science.gov (United States)

    Long, Jingming; Furch, Federico J.; Durá, Judith; Tremsin, Anton S.; Vallerga, John; Schulz, Claus Peter; Rouzée, Arnaud; Vrakking, Marc J. J.

    2017-07-01

    A new ion-ion coincidence imaging spectrometer based on a pixelated complementary metal-oxide-semiconductor detector has been developed for the investigation of molecular ionization and fragmentation processes in strong laser fields. Used as a part of a velocity map imaging spectrometer, the detection system is comprised of a set of microchannel plates and a Timepix detector. A fast time-to-digital converter (TDC) is used to enhance the ion time-of-flight resolution by correlating timestamps registered separately by the Timepix detector and the TDC. In addition, sub-pixel spatial resolution (algorithm. This performance is achieved while retaining a high event rate (104 per s). The spectrometer was characterized and used in a proof-of-principle experiment on strong field dissociative double ionization of carbon dioxide molecules (CO2), using a 400 kHz repetition rate laser system. The experimental results demonstrate that the spectrometer can detect multiple ions in coincidence, making it a valuable tool for studying the fragmentation dynamics of molecules in strong laser fields.

  19. Hadron Contribution to Vacuum Polarisation

    Science.gov (United States)

    Davier, M.; Hoecker, A.; Malaescu, B.; Zhang, Z.

    2016-10-01

    Precision tests of the Standard Theory require theoretical predictions taking into account higher-order quantum corrections. Among these vacuum polarisation plays a predominant role. Vacuum polarisation originates from creation and annihilation of virtual particle-antiparticle states. Leptonic vacuum polarisation can be computed from quantum electrodynamics. Hadronic vacuum polarisation cannot because of the non-perturbative nature of QCD at low energy. The problem is remedied by establishing dispersion relations involving experimental data on the cross section for e+ e- annihilation into hadrons. This chapter sets the theoretical and experimental scene and reviews the progress achieved in the last decades thanks to more precise and complete data sets. Among the various applications of hadronic vacuum polarisation calculations, two are emphasised: the contribution to the anomalous magnetic moment of the muon, and the running of the fine structure constant α to the Z mass scale. They are fundamental ingredients to high precision tests of the Standard Theory.

  20. An electrostatic ion pump with nanostructured Si field emission electron source and Ti particle collectors for supporting an ultra-high vacuum in miniaturized atom interferometry systems

    Science.gov (United States)

    Basu, Anirban; Velásquez-García, Luis F.

    2016-12-01

    We report a field emission-based, magnetic-less ion pump architecture for helping maintain a high vacuum within a small chamber that is compatible with miniaturized cold-atom interferometry systems. A nanostructured silicon field emitter array, with each nano-sharp tip surrounded by a self-aligned proximal gate electrode, is used to generate a surplus of electrons that cause impact ionization of gas molecules. A two-stage cylindrical electron collector, made of titanium, is used to increase the travel distance of the electrons, augmenting the ionization probability; gas ionization is subsequently followed by gettering of the ions by a negatively charged, annular-shaped titanium electrode. A proof-of-concept pump prototype was characterized using a 25 cm3 stainless steel vacuum chamber backed up by an external turbomolecular pump, a diaphragm pump, and a standard ion pump. Pumping action was observed with the electrostatic pump operating alone after an initial rapid rise of the chamber pressure due to electron/ion scrubbing. In addition, running the electrostatic pump in combination with the standard ion pump results in a lower vacuum level compared to the vacuum level produced by the standard ion pump acting alone. A proposed reduced-order model accurately predicts the functional dependence of the pressure versus time data and provides a good estimate of the characteristic pumping time constant inferred from the experiments.

  1. Electrical characterization of SiGeSn grown on Ge substrate using ultra high vacuum chemical vapor deposition

    Science.gov (United States)

    Ahoujja, Mo; Kang, S.; Hamilton, M.; Yeo, Y. K.; Kouvetakis, J.; Menendez, J.

    2012-02-01

    There has been recently considerable interest in growing SiyGe1-x-ySnx alloys for the fabrication of photonic devices that could be integrated with Si technologies. We report temperature dependent Hall (TDH) measurements of the hole concentration and mobility from high quality p-type doped Si0.08Ge0.90Sn0.02 layers grown on p-type doped Ge substrates using ultra high vacuum chemical vapor deposition. The TDH measurements show the hole sheet density remains constant at low temperatures before slightly decreasing and dipping at ˜ 125 K. It then exponentially increases with temperature due to the activation of shallow acceptors. At temperatures above ˜ 450 K, the hole sheet density increases sharply indicating the onset of intrinsic conduction in the SiGeSn and/or Ge layers. To extract the electrical properties of the SiGeSn layer alone, a parametric fit using a multi layer conducting model is applied to the measured hole concentration and mobility data. The analysis yields boron and gallium doping concentrations of 3x10^17 cm-3 and 1x10^18 cm-3 with activation energies of 10 meV and 11 meV for the SiGeSn layer and Ge substrate, respectively. Furthermore, a temperature independent hole sheet concentration of ˜5x10^15 cm-2 with a mobility of ˜250 cm^2/Vs, which is believed to be due to an interfacial layer between the SiGeSn layer and the Ge substrate, is also determined.

  2. Effect of high substrate bias and hydrogen and nitrogen incorporation on filtered cathodic vacuum arc deposited tetrahedral amorphous carbon films

    Energy Technology Data Exchange (ETDEWEB)

    Panwar, O.S. [Plasma Processed Materials Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi-110 012 (India)], E-mail: ospanwar@mail.nplindia.ernet.in; Khan, Mohd. Alim [Plasma Processed Materials Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi-110 012 (India); Kumar, Mahesh; Shivaprasad, S.M. [Surface Physics and Nanostructures Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi-110 012 (India); Satyanarayana, B.S. [MIT Innovation Centre and Electronics and Communication Department, Manipal Institute of Technology, Manipal-579104 (India); Dixit, P.N. [Plasma Processed Materials Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi-110 012 (India); Bhattacharyya, R. [Emeritus Scientist, National Physical Laboratory, New Delhi-110012 (India); Khan, M.Y. [Department of Physics, Jamia Millia Islamia, Central University, New Delhi-110025 (India)

    2008-02-29

    The application of a sufficiently high negative substrate bias, during the growth of tetrahedral amorphous carbon (ta-C), is usually associated with low sp{sup 3} bonding configuration and stressed films. However, in an effort to understand and utilize the higher pseudo thermo dynamical conditions during the film growth, at high negative substrate bias (- 300 V), reported here is a study on ta-C films grown under different hydrogen and nitrogen concentration. As grown ta-C films were studied under different negative substrate bias conditions. The variation of the sp{sup 3} content and sp{sup 3}/sp{sup 2} ratio in the ta-C films exhibits a trend similar to those reported in literature, with a subtle variation in this report being the substrate bias voltage, which was observed to be around - 200 V, for obtaining the highest sp{sup 3} (80%) bonding and sp{sup 3}/sp{sup 2} (3.95) ratio. The hydrogen and nitrogen incorporated ta-C films studied, at a bias of - 300 V, show an increase in sp{sup 3} (87-91%) bonding and sp{sup 3}/sp{sup 2} (7-10) ratio in the range of studies reported. The inference is drawn on the basis of the set of data obtained from measurements carried out using X-ray photoelectron spectroscopy, X-ray induced Auger electron spectroscopy and Raman spectroscopy of as grown and hydrogen and nitrogen incorporated ta-C films deposited using an S bend filtered cathodic vacuum arc system. The study indicates the possibility of further tailoring ta-C film properties and also extending capabilities of the cathodic arc system for developing carbon based films for electronics and tribological applications.

  3. Vacuum fiber-fiber coupler

    Science.gov (United States)

    Heinrici, Axel; Bjelajac, Goran; Jonkers, Jeroen; Jakobs, Stefan; Olschok, Simon; Reisgen, Uwe

    2017-02-01

    Research and development carried out by the ISF Welding and Joining Institute of RWTH Aachen University has proven that combining high power laser and low vacuum atmosphere provides a welding performance and quality, which is comparable to electron beam welding. The developed welding machines are still using a beam forming which takes place outside the vacuum and the focusing laser beam has to be introduced to the vacuum via a suitable window. This inflexible design spoils much of the flexibility of modern laser welding. With the target to bring a compact, lightweight flying optics with flexible laser transport fibers into vacuum chambers, a high power fiber-fiber coupler has been adapted by II-VI HIGHYAG that includes a reliable vacuum interface. The vacuum-fiber-fiber coupler (V-FFC) is tested with up to 16 kW sustained laser power and the design is flexible in terms of a wide variety of laser fiber plug systems and vacuum flanges. All that is needed to implement the V-FFC towards an existing or planned vacuum chamber is an aperture of at least 100 mm (4 inch) diameter with any type of vacuum or pressure flange. The V-FFC has a state-of-the-art safety interface which allows for fast fiber breakage detection for both fibers (as supported by fibers) by electric wire breakage and short circuit detection. Moreover, the System also provides connectors for cooling and electric signals for the laser beam optics inside the vacuum. The V-FFC has all necessary adjustment options for coupling the laser radiation to the receiving fiber.

  4. Set-up of a High-Resolution 300 mK Atomic Force Microscope in an Ultra-High Vacuum Compatible 3He/10T Cryostat

    CERN Document Server

    von Allwörden, Henning; Köhler, Arne; Eelbo, Thomas; Schwarz, Alexander; Wiesendanger, Roland

    2016-01-01

    The design of an atomic force microscope with an all-fiber interferometric detection scheme capable of atomic resolution at about 500 mK is presented. The microscope body is connected to a small pumped 3He reservoir with a base temperature of about 300 mK. The bakeable insert with the cooling stage can be moved from its measurement position inside the bore of a superconducting 10 T magnet into an ultra-high vacuum chamber, where tip and sample can be exchanged in-situ. Moreover, single atoms or molecules can be evaporated onto a cold substrate located inside the microscope. Two side chambers are equipped with standard surface preparation and surface analysis tools. The performance of the microscope at low temperatures is demonstrated by resolving single Co atoms on Mn/W(110) and by showing atomic resolution on NaCl(001).

  5. Set-up of a high-resolution 300 mK atomic force microscope in an ultra-high vacuum compatible 3He/10 T cryostat

    Science.gov (United States)

    von Allwörden, H.; Ruschmeier, K.; Köhler, A.; Eelbo, T.; Schwarz, A.; Wiesendanger, R.

    2016-07-01

    The design of an atomic force microscope with an all-fiber interferometric detection scheme capable of atomic resolution at about 500 mK is presented. The microscope body is connected to a small pumped 3He reservoir with a base temperature of about 300 mK. The bakeable insert with the cooling stage can be moved from its measurement position inside the bore of a superconducting 10 T magnet into an ultra-high vacuum chamber, where the tip and sample can be exchanged in situ. Moreover, single atoms or molecules can be evaporated onto a cold substrate located inside the microscope. Two side chambers are equipped with standard surface preparation and surface analysis tools. The performance of the microscope at low temperatures is demonstrated by resolving single Co atoms on Mn/W(110) and by showing atomic resolution on NaCl(001).

  6. Set-up of a high-resolution 300 mK atomic force microscope in an ultra-high vacuum compatible (3)He/10 T cryostat.

    Science.gov (United States)

    von Allwörden, H; Ruschmeier, K; Köhler, A; Eelbo, T; Schwarz, A; Wiesendanger, R

    2016-07-01

    The design of an atomic force microscope with an all-fiber interferometric detection scheme capable of atomic resolution at about 500 mK is presented. The microscope body is connected to a small pumped (3)He reservoir with a base temperature of about 300 mK. The bakeable insert with the cooling stage can be moved from its measurement position inside the bore of a superconducting 10 T magnet into an ultra-high vacuum chamber, where the tip and sample can be exchanged in situ. Moreover, single atoms or molecules can be evaporated onto a cold substrate located inside the microscope. Two side chambers are equipped with standard surface preparation and surface analysis tools. The performance of the microscope at low temperatures is demonstrated by resolving single Co atoms on Mn/W(110) and by showing atomic resolution on NaCl(001).

  7. Comment on "The Lamb Shift and Ultra High Energy Cosmic Rays" and Comment on "Vacuum Polarization Energy Losses of High Energy Cosmic Rays"

    CERN Document Server

    Deligny, O

    2002-01-01

    The cosmic rays spectrum has been shown to extend well beyond 10^20 eV. With nearly 20 events observed in the last 40 years, it is now established that particles with energies near or above 10^21 eV. No nearby astrophysical object has been shown to correlate with the arrival directions of the highest energy events, yet the exponential cut-off in the high energy end of the spectrum one expects to see in the case of far sources is not visible. It was recently pointed out that the influence of the vacuum of quantum electrodynamics on particle propagation could explain qualitatively this mystery. This note is a critic to these ideas.

  8. FOREWORD: The 4th CCM International Conference on Pressure Metrology from Ultra-High Vacuum to Very High Pressures (10-9 Pa to 109 Pa)

    Science.gov (United States)

    Legras, Jean-Claude; Jousten, Karl; Severn, Ian

    2005-12-01

    The fourth CCM (Consultative Committee for Mass and related quantities) International Conference on Pressure Metrology from Ultra-High Vacuum to Very High Pressures (10-9 Pa to 109 Pa) was held at the Institute of Physics in London from 19-21 April 2005. The event, which was organized by the Low, Medium and High Pressure working groups of the CCM, was attended by in excess of one hundred participants with representatives from five continents and every regional metrology organization. The purpose of this conference is to review all the work that is devoted to the highest quality of pressure measurement by primary standards as well as the dissemination of the pressure scale. A total of 52 papers were presented orally, and 26 as posters, in sessions that covered the following topics: Latest scientific advances in pressure and vacuum metrology Innovative transfer standards, advanced sensors and new instrument development Primary (top-level) measurement standards International and regional key comparisons New approaches to calibration It is interesting the note that since the third conference in 1999 the pressure range covered has increased by two orders of magnitude to 109 Pa, to take into account more exacting scientific and industrial demands for traceable vacuum measurement. A further feature of the conference was the increased range of instrumentation and techniques used in the realization and potential realization of pressure standards. Seton Bennett, Director of International Metrology at the National Physical Laboratory, opened the conference and Andrew Wallard, Director of the Bureau International des Poids et Mesures (BIPM), gave the keynote address which described the implementation of the mutual recognition arrangement and the resulting removal of metrological barriers to international trade. Many experts have contributed significant amounts of their time to organize the event and to review the submitted papers. Thanks are due to all of these people

  9. Assessing the feasibility of a high-temperature, helium-cooled vacuum vessel and first wall for the Vulcan tokamak conceptual design

    Energy Technology Data Exchange (ETDEWEB)

    Barnard, H.S., E-mail: hbar@mit.edu [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA (United States); Hartwig, Z.S.; Olynyk, G.M.; Payne, J.E. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA (United States)

    2012-03-15

    The Vulcan conceptual design (R = 1.2 m, a = 0.3 m, B{sub 0} = 7 T), a compact, steady-state tokamak for plasma-material interaction (PMI) science, must incorporate a vacuum vessel capable of operating at 1000 K in order to replicate the temperature-dependent physical chemistry that will govern PMI in a reactor. In addition, the Vulcan divertor must be capable of handling steady-state heat fluxes up to 10 MW m{sup -2} so that integrated materials testing can be performed under reactor-relevant conditions. A conceptual design scoping study has been performed to assess the challenges involved in achieving such a configuration. The Vulcan vacuum system comprises an inner, primary vacuum vessel that is thermally and mechanically isolated from the outer, secondary vacuum vessel by a 10 cm vacuum gap. The thermal isolation minimizes heat conduction between the high-temperature helium-cooled primary vessel and the water-cooled secondary vessel. The mechanical isolation allows for thermal expansion and enables vertical removal of the primary vessel for maintenance or replacement. Access to the primary vessel for diagnostics, lower hybrid waveguides, and helium coolant is achieved through {approx}1 m long intra-vessel pipes to minimize temperature gradients and is shown to be commensurate with the available port space in Vulcan. The isolated primary vacuum vessel is shown to be mechanically feasible and robust to plasma disruptions with analytic calculations and finite element analyses. Heat removal in the first wall and divertor, coupled with the ability to perform in situ maintenance and replacement of divertor components for scientific purposes, is achieved by combining existing helium-cooled techniques with innovative mechanical attachments of plasma facing components, either in plate-type helium-cooled modules or independently bolted, helium-jet impingement-cooled tiles. The vacuum vessel and first wall design enables a wide range of potential PFC materials and

  10. Household vacuum cleaners vs. the high-volume surface sampler for collection of carpet dust samples in epidemiologic studies of children

    Directory of Open Access Journals (Sweden)

    Buffler Patricia A

    2008-02-01

    Full Text Available Abstract Background Levels of pesticides and other compounds in carpet dust can be useful indicators of exposure in epidemiologic studies, particularly for young children who are in frequent contact with carpets. The high-volume surface sampler (HVS3 is often used to collect dust samples in the room in which the child had spent the most time. This method can be expensive and cumbersome, and it has been suggested that an easier method would be to remove dust that had already been collected with the household vacuum cleaner. However, the household vacuum integrates exposures over multiple rooms, some of which are not relevant to the child's exposure, and differences in vacuuming equipment and practices could affect the chemical concentration data. Here, we compare levels of pesticides and other compounds in dust from household vacuums to that collected using the HVS3. Methods Both methods were used in 45 homes in California. HVS3 samples were collected in one room, while the household vacuum had typically been used throughout the home. The samples were analyzed for 64 organic compounds, including pesticides, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls (PCBs, using GC/MS in multiple ion monitoring mode; and for nine metals using conventional microwave-assisted acid digestion combined with ICP/MS. Results The methods agreed in detecting the presence of the compounds 77% to 100% of the time (median 95%. For compounds with less than 100% agreement, neither method was consistently more sensitive than the other. Median concentrations were similar for most analytes, and Spearman correlation coefficients were 0.60 or higher except for allethrin (0.15 and malathion (0.24, which were detected infrequently, and benzo(kfluoranthene (0.55, benzo(apyrene (0.55, PCB 105 (0.54, PCB 118 (0.54, and PCB 138 (0.58. Assuming that the HVS3 method is the "gold standard," the extent to which the household vacuum cleaner method yields relative risk

  11. INTENSIFICATION OF HEAT- AND MASS TRANSFER IN EVAPORATION - CONDENSATION DEVICES

    OpenAIRE

    A. G. Kulakov

    2005-01-01

    Results of investigation of capillary structure properties used in evaporation – condensation devices are presented.Constructive solutions for intensification of heat transfer in evaporation and condensation heat exchangers are offered. The obtained heat transfer experimental data at film-type vapor conden-sation are generalized in criterion form.Description of general rule of heat and mass transfer processes in miniature heat pipes with three various capillary structures at wide range of ope...

  12. Superhydrophobic coated apparatus for liquid purification by evaporative condensation

    Science.gov (United States)

    Simpson, John T; McNeany, Steve R; Dinsmore, Thomas V; Hunter, Scott R; Ivanov, Ilia N

    2014-03-11

    Disclosed are examples of apparatuses for evaporative purification of a contaminated liquid. In each example, there is a first vessel for storing the contaminated fluid. The first vessel includes a surface coated with a layer of superhydrophobic material and the surface is at least partially in contact with the contaminated liquid. The contaminants do not adhere to the surface as the purified liquid evaporates, thus simplifying maintenance of the apparatus.

  13. Effect of Evaporation-Condensation on Photoacoustics of Aerosols

    Science.gov (United States)

    2007-11-02

    Gases and Liquids, (Wiley, New York, 1954). 9F. Reif , Fundamentals of Statistical and Thermal Physics, (McGraw - Hill, New York, 1965). l0Alan D. Pierce...been provided for the mechanism of decrease. The data set will be further analyzed, and compared with theory. 4 2. THEORY OF THE EFFECT OF EVPORATION...and E.M. Lifshitz, Fluid Mechanics , (Butterworth-Heinemann, Oxford 1997), 2 nd Ed. 8J.V. Hirschfelder, C. Curtiss, R. B. Bird, Molecular Theory of

  14. Consistency of Students' Ideas across Evaporation, Condensation, and Boiling

    Science.gov (United States)

    Kirbulut, Zubeyde Demet; Beeth, Michael Edward

    2013-01-01

    Existing research on students' conceptions contain competing philosophical positions concerning the nature of students' ideas--whether those ideas are coherent, systematic and theory-like, or fragmented and incoherent. Existing research has also focused primarily on studies of individual conceptions rather than investigating multiple, related…

  15. Consistency of Students' Ideas across Evaporation, Condensation, and Boiling

    Science.gov (United States)

    Kirbulut, Zubeyde Demet; Beeth, Michael Edward

    2013-01-01

    Existing research on students' conceptions contain competing philosophical positions concerning the nature of students' ideas--whether those ideas are coherent, systematic and theory-like, or fragmented and incoherent. Existing research has also focused primarily on studies of individual conceptions rather than investigating multiple, related…

  16. Passive evaporation-condensation system for laser cooling

    Directory of Open Access Journals (Sweden)

    Gershuni A. N.

    2012-04-01

    Full Text Available A special heat pipe for ensuring the thermal regime of the active element of an optical quantum generator (laser under heat sink by radiation has been developed. It is shown that under the simulated fuel element power of 50 W wall temperature in the heat pipe heating zone does not exceed 30°C, and the emergency heating prevents deep freezing of the entire system in the absence of heat generation of the object itself.

  17. Vacuum production; Produccion de vacio

    Energy Technology Data Exchange (ETDEWEB)

    Segovia, J. L. de

    2010-07-01

    Since the advent of ultra high vacuum in 1958 has been a great demand for new as means of production and to meet the process needs to be done: industry heavy, high technology and space research areas, large accelerator systems particles or nuclear fusion. In this paper we explore the modern media production: dry vacuum pumps, turbo pumps, pump status diffusion ion pumps and cryopumps. (Author)

  18. Direct comparison of highly efficient solution- and vacuum-processed organic solar cells based on merocyanine dyes

    Energy Technology Data Exchange (ETDEWEB)

    Kronenberg, Nils M.; Steinmann, Vera; Hertel, Dirk; Meerholz, Klaus [Department fuer Chemie, Universitaet Koeln, Luxemburger Strasse 116, 50939 Koeln (Germany); Buerckstuemmer, Hannah; Wuerthner, Frank [Institut fuer Organische Chemie and Roentgen Research Center for Complex Material Systems, Universitaet Wuerzburg, Am Hubland, 97074 Wuerzburg (Germany); Hwang, Jaehyung [BASF SE, Carl-Bosch-Strasse 38, 67056 Ludwigshafen (Germany)

    2010-10-01

    Identically configured bulk heterojunction organic solar cells based on merocyanine dye donor and fullerene acceptor compounds are manufactured either from solution or by vacuum deposition, to enable a direct comparison. Whereas the former approach is more suitable for screening purposes, the latter approach affords higher short-circuit current density and power conversion efficiency. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  19. Direct comparison of highly efficient solution- and vacuum-processed organic solar cells based on merocyanine dyes.

    Science.gov (United States)

    Kronenberg, Nils M; Steinmann, Vera; Bürckstümmer, Hannah; Hwang, Jaehyung; Hertel, Dirk; Würthner, Frank; Meerholz, Klaus

    2010-10-01

    Identically configured bulk heterojunction organic solar cells based on merocyanine dye donor and fullerene acceptor compounds (see figure) are manufactured either from solution or by vacuum deposition, to enable a direct comparison. Whereas the former approach is more suitable for screening purposes, the latter approach affords higher short-circuit current density and power conversion efficiency.

  20. Use of vacuum tubes in test instrumentation for measuring characteristics of fast high-voltage semiconductor devices

    Science.gov (United States)

    Berning, D.

    1981-01-01

    Circuits are described that permit measurement of fast events occurring in power semiconductors. These circuits were developed for the dynamic characterization of transistors used in inductive-load switching applications. Fast voltage clamping using vacuum diodes is discussed, and reference is made to a unique circuit that was built for performing nondestructive, reverse-bias, second-breakdown tests on transistors.

  1. Vacuum Brazing of Accelerator Components

    Science.gov (United States)

    Singh, Rajvir; Pant, K. K.; Lal, Shankar; Yadav, D. P.; Garg, S. R.; Raghuvanshi, V. K.; Mundra, G.

    2012-11-01

    Commonly used materials for accelerator components are those which are vacuum compatible and thermally conductive. Stainless steel, aluminum and copper are common among them. Stainless steel is a poor heat conductor and not very common in use where good thermal conductivity is required. Aluminum and copper and their alloys meet the above requirements and are frequently used for the above purpose. The accelerator components made of aluminum and its alloys using welding process have become a common practice now a days. It is mandatory to use copper and its other grades in RF devices required for accelerators. Beam line and Front End components of the accelerators are fabricated from stainless steel and OFHC copper. Fabrication of components made of copper using welding process is very difficult and in most of the cases it is impossible. Fabrication and joining in such cases is possible using brazing process especially under vacuum and inert gas atmosphere. Several accelerator components have been vacuum brazed for Indus projects at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore using vacuum brazing facility available at RRCAT, Indore. This paper presents details regarding development of the above mentioned high value and strategic components/assemblies. It will include basics required for vacuum brazing, details of vacuum brazing facility, joint design, fixturing of the jobs, selection of filler alloys, optimization of brazing parameters so as to obtain high quality brazed joints, brief description of vacuum brazed accelerator components etc.

  2. Effect of High Temperature Storage in Vacuum, Air, and Humid Conditions on Degradation of Gold/Aluminum Wire Bonds in PEMs

    Science.gov (United States)

    Teverovsky, Alexander

    2006-01-01

    Microcircuits encapsulated in three plastic package styles were stored in different environments at temperatures varying from 130 C to 225 C for up to 4,000 hours in some cases. To assess the effect of oxygen, the parts were aged at high temperatures in air and in vacuum chambers. The effect of humidity was evaluated during long-term highly accelerated temperature and humidity stress testing (HAST) at temperatures of 130 C and 150 C. High temperature storage testing of decapsulated microcircuits in air, vacuum, and HAST chambers was carried out to evaluate the role of molding compounds in the environmentally-induced degradation and failure of wire bonds (WB). This paper reports on accelerating factors of environment and molding compound on WB failures. It has been shown that all environments, including oxygen, moisture, and the presence of molding compounds reduce time-to-failures compared to unencapsulated devices in vacuum conditions. The mechanism of the environmental effect on KB degradation is discussed.

  3. Quantum Electrodynamics vacuum polarization solver

    CERN Document Server

    Carneiro, Pedro; Fonseca, Ricardo; Silva, Luís

    2016-01-01

    The self-consistent modeling of vacuum polarization due to virtual electron-positron fluctuations is of relevance for many near term experiments associated with high intensity radiation sources and represents a milestone in describing scenarios of extreme energy density. We present a generalized finite-difference time-domain solver that can incorporate the modifications to Maxwells equations due to virtual vacuum polarization. Our multidimensional solver reproduced in one dimensional configurations the results for which an analytic treatment is possible, yielding vacuum harmonic generation and birefringence. The solver has also been tested for two-dimensional scenarios where finite laser beam spot sizes must be taken into account. We employ this solver to explore different types of counter-propagating configurations that can be relevant for future planned experiments aiming to detect quantum vacuum dynamics at ultra-high electromagnetic field intensities.

  4. Combined high-pressure cell-ultrahigh vacuum system for fast testing of model metal alloy catalysts using scanning mass spectrometry

    DEFF Research Database (Denmark)

    Johansson, Martin; Jørgensen, Jan Hoffmann; Chorkendorff, Ib

    2004-01-01

    An apparatus for fabrication, surface analysis in ultrahigh vacuum, and testing of the catalytic activity of model metal alloy catalysts is described. Arrays of model catalysts are produced by electron-beam deposition of up to four metals simultaneously onto a substrate. The surface analysis...... techniques available are scanning electron microscopy, x-ray photoemission spectroscopy, ion scattering spectroscopy, Auger electron spectroscopy, sputter profiling, and temperature programmed desorption. The catalytic activity of the model catalysts is tested individually by scanning a combined gas delivery...... be studied on a substrate 10 mm in diameter. A high pressure cell with an all-metal sealed ultrahigh vacuum lock is also described as part of the work. ©2004 American Institute of Physics....

  5. Overview spectra and axial distribution of spectral line intensities in a high-current vacuum arc with CuCr electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Lisnyak, M.; Pipa, A. V.; Gorchakov, S., E-mail: gorchakov@inp-greifswald.de, E-mail: weltmann@inp-greifswald.de; Iseni, S.; Franke, St.; Khapour, A.; Methling, R.; Weltmann, K.-D., E-mail: gorchakov@inp-greifswald.de, E-mail: weltmann@inp-greifswald.de [Leibniz-Institut für Plasmaforschung und Technologie e.V., Felix-Hausdorff-Straße 2, 17489 Greifswald (Germany)

    2015-09-28

    Spectroscopic investigations of free-burning vacuum arcs in diffuse mode with CuCr electrodes are presented. The experimental conditions of the investigated arc correspond to the typical system for vacuum circuit breakers. Spectra of six species Cu I, Cu II, Cu III, Cr I, Cr II, and Cr III have been analyzed in the wavelength range 350–810 nm. The axial intensity distributions were found to be strongly dependent on the ionization stage of radiating species. Emission distributions of Cr II and Cu II can be distinguished as well as the distributions of Cr III and Cu III. Information on the axial distribution was used to identify the spectra and for identification of overlapping spectral lines. The overview spectra and some spectral windows recorded with high resolution are presented. Analysis of axial distributions of emitted light, which originates from different ionization states, is presented and discussed.

  6. Vacuum-Packaging Technology for IRFPAs

    Science.gov (United States)

    Matsumura, Takeshi; Tokuda, Takayuki; Tsutinaga, Akinobu; Kimata, Masafumi; Abe, Hideyuki; Tokashiki, Naotaka

    We developed vacuum-packaging equipment and low-cost vacuum packaging technology for IRFPAs. The equipment is versatile and can process packages with various materials and structures. Getters are activated before vacuum packaging, and we can solder caps/ceramic-packages and caps/windows in a high-vacuum condition using this equipment. We also developed a micro-vacuum gauge to measure pressure in vacuum packages. The micro-vacuum gauge uses the principle of thermal conduction of gases. We use a multi-ceramic package that consists of six packages fabricated on a ceramic sheet, and confirm that the pressure in the processed packages is sufficiently low for high-performance IRFPA.

  7. Experimental Investigation on the Influence of Axial Magnetic Field Distribution on Resisting the Constriction of a High-Current Vacuum Arc

    Institute of Scientific and Technical Information of China (English)

    SHI Zongqian; LIU Zhigang; JIA Shenli; SONG Xiaochuan; WANG Lijun

    2009-01-01

    Effect of the axial magnetic field (AMF) on resisting the constriction of a high-current vacuum arc is studied in this paper. Two typical AMF distributions were investigated, i.e., the traditional bell-shaped AMF, and the saddle-shaped AMF. Experiments were conducted in a detachable vacuum chamber with a rms arc current in the range of 10 kA to 25 kA. The arc column was photographed by a high-speed digital camera with an exposure time of 2 microseconds. The constriction of the vacuum arc was compared by processing the images of the arc column under the two different field configurations and numerically determining the dimensions of the arc column near the electrodes. It was also confirmed that the AMF distribution had a signifcant influence on its effectiveness in resisting arc constriction, Furthermore, the AMF strength near the periphery of the arc is more influential than that at the centre of the electrodes in resisting arc constriction.

  8. Vacuum mechatronics. Proceedings.

    Science.gov (United States)

    Belinski, S. E.; Shirazi, M.; Hackwood, S.; Beni, G.

    The discipline of vacuum mechatronics is the design and development of vacuum-compatible, computer-controlled mechanisms for manipulating, sensing and testing in a vacuum environment. Vacuum mechantronics is relevant to research engineers in integrated circuit manufacturing, surface physics, food processing, biotechnology, materials handling, space sciences and manufacturing.

  9. Development of Subischial Prosthetic Sockets with Vacuum-Assisted Suspension for Highly Active Persons with Transfemoral Amputations

    Science.gov (United States)

    2014-10-01

    International Organization for Stan- dardization, Li-Ion = lithium -ion, VAS = vacuum-assisted sus- pension. *Address all correspondence to Stefania Fatone...both electrical pumps, a lithium -ion (Li-Ion) battery powered a direct current motor, which ran a small capacity pump. Microprocessor circuitry...were deter- mined prior to initiation of the test. At the three weight settings tested for the Harmony P2 and Harmony HD pumps, there were no

  10. 大功率微波真空电子器件的应用%Application of high power microwave vacuum electron devices

    Institute of Scientific and Technical Information of China (English)

    丁耀根; 刘濮鲲; 张兆传; 王勇; 沈斌

    2011-01-01

    大功率微波真空电子器件具有工作频率高、峰值和平均功率大等特点,已广泛应用于微波电子系统,在科学研究和国民经济方面的应用越来越广泛.在科学研究方面,它主要应用在高能粒子加速器和可控热核聚变加热装置等大型科学装置上,主要包括高峰值功率速调管、连续波和长脉冲高功率速调管和高功率回旋管等器件.在国民经济方面,则主要应用于天气雷达、导航雷达、医用和工业辐照加速器、电视广播和通信等微波电子系统,主要包括大功率脉冲和连续波速调管、分布作用速调管、行波管、磁控管和感应输出管等.为此,介绍了这些微波真空电子器件的技术现状、共性技术问题和发展趋势.%High power microwave vacuum electron devices can work at high frequency, high peak and average power. They have been widely used in military and civil microwave electron systems, such as radar, communication, countermeasure, TV broadcast, particle accelerators, plasma heating devices of fusion, microwave sensing and microwave heating. In scientific research, high power microwave vacuum electron devices are used mainly on high energy particle accelerator and fusion research. The devices include high peak power klystron, CW and long pulse high power klystron, multi-beam klystron, and high power gy-rotron. In national economy, high power microwave vacuum electron devices are used mainly on weather and navigation radar, medical and radiation accelerator, TV broadcast and communication system. The devices include high power pulse and CW klystron, extended interaction klystron, traveling wave tube(TWT), magnetron and induced output tube(IOT). The state of art, common technology problems and trends of high power microwave vacuum electron devices are introduced in this paper.

  11. Ultra high vacuum high precision low background setup with temperature control for thermal desorption mass spectroscopy (TDA-MS) of hydrogen in metals.

    Science.gov (United States)

    Merzlikin, Sergiy V; Borodin, S; Vogel, D; Rohwerder, M

    2015-05-01

    In this work, a newly developed UHV-based high precision low background setup for hydrogen thermal desorption analysis (TDA) of metallic samples is presented. Using an infrared heating with a low thermal capacity enables a precise control of the temperature and rapid cool down of the measurement chamber. This novel TDA-set up is superior in sensitivity to almost every standard hydrogen analyzer available commercially due to the special design of the measurement chamber, resulting in a very low hydrogen background. No effects of background drift characteristic as for carrier gas based TDA instruments were observed, ensuring linearity and reproducibility of the analysis. This setup will prove to be valuable for detailed investigations of hydrogen trapping sites in steels and other alloys. With a determined limit of detection of 5.9×10(-3)µg g(-1) hydrogen the developed instrument is able to determine extremely low hydrogen amounts even at very low hydrogen desorption rates. This work clearly demonstrates the great potential of ultra-high vacuum thermal desorption mass spectroscopy instrumentation.

  12. Design and performance of an ultra-high vacuum scanning tunneling microscope operating at dilution refrigerator temperatures and high magnetic fields

    CERN Document Server

    Misra, Shashank; Drozdov, Ilya K; Seo, Jungpil; Gyenis, Andras; Kingsley, Simon C J; Jones, Howard; Yazdani, Ali

    2013-01-01

    We describe the construction and performance of a scanning tunneling microscope (STM) capable of taking maps of the tunneling density of states with sub-atomic spatial resolution at dilution refrigerator temperatures and high (14 T) magnetic fields. The fully ultra-high vacuum system features visual access to a two-sample microscope stage at the end of a bottom-loading dilution refrigerator, which facilitates the transfer of in situ prepared tips and samples. The two-sample stage enables location of the best area of the sample under study and extends the experiment lifetime. The successful thermal anchoring of the microscope, described in detail, is confirmed through a base temperature reading of 20 mK, along with a measured electron temperature of 250 mK. Atomically-resolved images, along with complementary vibration measurements, are presented to confirm the effectiveness of the vibration isolation scheme in this instrument. Finally, we demonstrate that the microscope is capable of the same level of perform...

  13. Development of high-pressure dry ice blasting method for decontamination. 3. Barrel type- and vacuum type- dry ice blasting methods

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Ryuichirou; Ishijima, Noboru; Morishita, Yoshitsugu; Tanimoto, Ken-ichi

    1997-05-01

    In order to decrease radioactivity of high-level radioactive wastes to low-level (lower than 500 {mu}Sv/h), the dry-ice blasting method has been developing. This method can decontaminate radioactive wastes up to 10{sup 2} in decontamination factor, and can minimize the secondary generated wastes. However, the method was not applicable to smaller and lighter objects because the objects scatter with the blasting flow. Two types of decontamination method, which are a barrel type- and a vacuum type- dry ice blasting methods, therefore, were planned. The barrel type method can decontaminate smaller solid wastes with preventing the scattering of the wastes by blast pressure. The vacuum type method has advantages to localize and collect the removed contamination from larger wastes. In this work, their basic efficiency on decontamination were investigated experimentally using painted specimens simulating contaminated wastes. Basic characteristics regarding with both barrel type- and the vacuum type- methods were obtained from above experiments. Moreover, items to be improved were clarified. (J.P.N.)

  14. Maintenance measures for preservation and recovery of permeable pavement surface infiltration rate--The effects of street sweeping, vacuum cleaning, high pressure washing, and milling.

    Science.gov (United States)

    Winston, Ryan J; Al-Rubaei, Ahmed M; Blecken, Godecke T; Viklander, Maria; Hunt, William F

    2016-03-15

    The surface infiltration rates (SIR) of permeable pavements decline with time as sediment and debris clog pore spaces. Effective maintenance techniques are needed to ensure the hydraulic functionality and water quality benefits of this stormwater control. Eight different small-scale and full-scale maintenance techniques aimed at recovering pavement permeability were evaluated at ten different permeable pavement sites in the USA and Sweden. Maintenance techniques included manual removal of the upper 2 cm of fill material, mechanical street sweeping, regenerative-air street sweeping, vacuum street sweeping, hand-held vacuuming, high pressure washing, and milling of porous asphalt. The removal of the upper 2 cm of clogging material did not significantly improve the SIR of concrete grid paves (CGP) and permeable interlocking concrete pavers (PICP) due to the inclusion of fines in the joint and bedding stone during construction, suggesting routine maintenance cannot overcome improper construction. For porous asphalt maintenance, industrial hand-held vacuum cleaning, pressure washing, and milling were increasingly successful at recovering the SIR. Milling to a depth of 2.5 cm nearly restored the SIR for a 21-year old porous asphalt pavement to like-new conditions. For PICP, street sweepers employing suction were shown to be preferable to mechanical sweepers; additionally, maintenance efforts may become more intensive over time to maintain a threshold SIR, as maintenance was not 100% effective at removing clogging material.

  15. Vacuum Technology and Standardization-An Update

    Science.gov (United States)

    Akram, H. M.; Rashid, H.

    2011-06-01

    Vacuum technology has been vital for the progress in almost every field of modern industrial & scientific research and technological developments. Research in this field is therefore important for the rapid progress in other sophisticated technologies. The modern society require precise know-how of vacuum metrology for its complex and sophisticated manufacturing processes and research activities. Accuracy in vacuum measurements is therefore an essential need for every application. The required accuracy is achieved with the help of well-calibrated vacuum gauges and this is possible only, if there exist proper vacuum standards of required range and accuracy. In this paper, a brief review of recently developed different vacuum standards, namely Standard Mercury Manometer, Standard Volume Expansion System and Standard Orifice Flow System will be presented, employed for the calibration of low, medium and high vacuum gauges respectively. Our recently developed standards are simple in design, least in vibration & degassing rate with desired accuracy, ease of operation and cost effective.

  16. Research on energy consumption in actual production of vacuum freeze-dried garlic slice%真空冷冻干燥蒜丁实际生产的能耗研究

    Institute of Scientific and Technical Information of China (English)

    刘业凤; 周国梁; 李续

    2014-01-01

    为了研究真空冷冻干燥蒜丁实际生产的能耗组成及节能措施,该文根据实地考察食品冷冻干燥厂蒜丁的真空冷冻干燥生产过程所得的资料,研究了冻干蒜丁实际生产过程的能耗,得到实际生产时单位脱水能耗为1.19 kW·h/kg,满足行业标准JB/T 10285-2001规定的冻干设备单位脱水量能耗不高于规定值即蒸汽加热单位脱水耗电量1.22 kW·h/kg的105%的要求。分析了生产过程中产品冻结、冻干过程中制冷系统、真空系统、加热系统、控制系统4大部分的能耗组成,从适当提高制冷系统蒸发温度及提高干燥仓压力等方面提出一些建议并达到了节能的目的,为以后食品冷冻干燥生产的节能设计提供一定参考。%Vacuum Freeze Drying has a great impact upon the production of dehydrated food because of the superior quality of the product obtained. Whereas, due to the slow rate of vacuum freeze drying, the long operation cycle, the high energy consumption generated by the vacuum freeze drying machine at run time, the development of freeze drying food will be restricted. In order to find energy-efficient approaches and seek lower cost productions, investigation was made on the process of freeze-dried garlic slice production in the freeze-dried food factory. In this paper, through analyzing the basic principle and drying process of vacuum freeze-dried garlic slice, energy consumption of refrigerating system, heating system and vacuum pump system was studied. By asking technicians and production manager from the factory, the main processing technology was learned. In addition, according to the experiences and field investigation, the technical date of lyophilized system including compressor, evaporator, condenser, ammonia pump, drying chamber and industrial boiler was learned as well as the stable parameter during the actual production process. Based on the obtained datum, using the principle of refrigeration

  17. Proposal to negotiate a collaboration agreement for the design and prototyping of a machine for laser treatment of metallic vacuum chamber walls for electron cloud mitigation at the High Luminosity LHC

    CERN Document Server

    2016-01-01

    Proposal to negotiate a collaboration agreement for the design and prototyping of a machine for laser treatment of metallic vacuum chamber walls for electron cloud mitigation at the High Luminosity LHC

  18. The vacuum universe the vacuum deposit and the dimensional hierarchy

    CERN Document Server

    Chung Ding Yu

    2001-01-01

    In this paper, it is proposed that the universe not only gains its existence from the vacuum but also fattens itself with the vacuum. It is the vacuum universe. The vacuum is deposited in the inflationary universe before the inflation. During the inflation, the deposited vacuum is spent to acquire space. In terms of elementary particles, the deposited vacuum is spent to dilute (fractionalize) the primordial high mass mixed 9-branes to form the low mass hierarchical mixed branes from 9 to 3 whose masses decrease with the space-time dimension numbers. This formation of the hierarchical mixed branes is followed by the internal empty space formation. The internal empty space is generate internally by the annihilation of some of the mixed branes through charge symmetry. The energy released is cosmic radiation. The inflationary emergence of the hierarchical mixed branes and the non-inflationary emergence of cosmic radiation after the inflation constitute the hybrid inflation. The mixed 3-brane is the mixture of lep...

  19. Fabrication of highly transparent Al-ion-implanted ZnO thin films by metal vapor vacuum arc method

    Science.gov (United States)

    Lee, Han; Sivashanmugan, Kundan; Kao, Chi-Yuan; Liao, Jiunn-Der

    2017-03-01

    In this study, we utilized the metal vapor vacuum arc technique to implant vaporized aluminum (Al) ions in zinc oxide (ZnO) thin films. By adjusting the ion implantation dose and operational parameters, the conductivity and optical properties of the ZnO thin film can be controlled. The electrical sheet resistance of Al-ion-implanted ZnO decreased from 3.02 × 107 to 3.03 × 104 Ω/sq, while the transparency of the film was mostly preserved (91.5% at a wavelength of 550 nm). The ZnO thin-film Young’s modulus significantly increased with increasing Al ion dose.

  20. The effect of molybdenum on niobium, titanium carbonitride precipitate evolution and grain refinement in high-temperature vacuum carburizing alloys

    Science.gov (United States)

    Enloe, Charles M.

    Existing commercial carburizing alloys can be processed at higher temperatures and shorter processing times utilizing vacuum carburizing due to the suppression of intergranular oxidation. To provide resistance to undesired grain coarsening at these elevated temperatures and associated reduction in fatigue performance, microalloyed steel variants have been developed which employ fine Ti- and Nb-carbonitrides to suppress grain growth. Grain coarsening resistance is believed to be limited by the coarsening resistance of the precipitates themselves at high temperature, so further alloy/processing developments to enhance microalloy precipitate coarsening resistance based on a greater mechanistic understanding of solute interaction with microalloy precipitates would be beneficial. Molybdenum is known to affect microalloy precipitate evolution during processing in ferrite and austenite, but a unified explanation of the role of Mo in precipitate evolution is still lacking. Accordingly, the effect of molybdenum on microalloy precipitate size and composition evolutions and the associated onset of abnormal grain growth in austenite was investigated in Mo-bearing and Mo-free, Nb,Ti-microalloyed SAE 4120 steels. Molybdenum additions of 0.30 wt pct to alloys containing Nb additions of 0.05 and 0.10 wt pct Nb delayed the onset of abnormal grain growth in hot-rolled alloys reheated and soaked at 1050 °C and 1100 °C. The coarsening rate of microalloy precipitates was also reduced in Mo-bearing alloys relative to Mo-free alloys during isothermal soaking at 1050 °C, 1100 °C, and 1150 °C. The observed microalloy precipitate coarsening rates exceeded those predicted by the Lifshitz-Slyozov-Wagner relation for volume-diffusion-controlled coarsening, which is attributed to an initial bimodal precipitate size distribution prior to reheating to elevated temperature. Heat-treatments of hot-rolled alloys (tempering and solutionizing) prior to reheating to elevated temperature in

  1. Indian Vacuum Society: The Indian Vacuum Society

    Science.gov (United States)

    Saha, T. K.

    2008-03-01

    The Indian Vacuum Society (IVS) was established in 1970. It has over 800 members including many from Industry and R & D Institutions spread throughout India. The society has an active chapter at Kolkata. The society was formed with the main aim to promote, encourage and develop the growth of Vacuum Science, Techniques and Applications in India. In order to achieve this aim it has conducted a number of short term courses at graduate and technician levels on vacuum science and technology on topics ranging from low vacuum to ultrahigh vacuum So far it has conducted 39 such courses at different parts of the country and imparted training to more than 1200 persons in the field. Some of these courses were in-plant training courses conducted on the premises of the establishment and designed to take care of the special needs of the establishment. IVS also regularly conducts national and international seminars and symposia on vacuum science and technology with special emphasis on some theme related to applications of vacuum. A large number of delegates from all over India take part in the deliberations of such seminars and symposia and present their work. IVS also arranges technical visits to different industries and research institutes. The society also helped in the UNESCO sponsored post-graduate level courses in vacuum science, technology and applications conducted by Mumbai University. The society has also designed a certificate and diploma course for graduate level students studying vacuum science and technology and has submitted a syllabus to the academic council of the University of Mumbai for their approval, we hope that some colleges affiliated to the university will start this course from the coming academic year. IVS extended its support in standardizing many of the vacuum instruments and played a vital role in helping to set up a Regional Testing Centre along with BARC. As part of the development of vacuum education, the society arranges the participation of

  2. ITER diagnostic system: Vacuum interface

    Energy Technology Data Exchange (ETDEWEB)

    Patel, K.M., E-mail: Kaushal.Patel@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-Lez-Durance (France); Udintsev, V.S.; Hughes, S.; Walker, C.I.; Andrew, P.; Barnsley, R.; Bertalot, L. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-Lez-Durance (France); Drevon, J.M. [Bertin Technologies, BP 22, 13762 Aix-en Provence cedex 3 (France); Encheva, A. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-Lez-Durance (France); Kashchuk, Y. [Institution “PROJECT CENTER ITER”, 1, Akademika Kurchatova pl., Moscow (Russian Federation); Maquet, Ph. [Bertin Technologies, BP 22, 13762 Aix-en Provence cedex 3 (France); Pearce, R.; Taylor, N.; Vayakis, G.; Walsh, M.J. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-Lez-Durance (France)

    2013-10-15

    Diagnostics play an essential role for the successful operation of the ITER tokamak. They provide the means to observe control and to measure plasma during the operation of ITER tokamak. The components of the diagnostic system in the ITER tokamak will be installed in the vacuum vessel, in the cryostat, in the upper, equatorial and divertor ports, in the divertor cassettes and racks, as well as in various buildings. Diagnostic components that are placed in a high radiation environment are expected to operate for the life of ITER. There are approx. 45 diagnostic systems located on ITER. Some diagnostics incorporate direct or independently pumped extensions to maintain their necessary vacuum conditions. They require a base pressure less than 10{sup −7} Pa, irrespective of plasma operation, and a leak rate of less than 10{sup −10} Pa m{sup 3} s{sup −1}. In all the cases it is essential to maintain the ITER closed fuel cycle. These directly coupled diagnostic systems are an integral part of the ITER vacuum containment and are therefore subject to the same design requirements for tritium and active gas confinement, for all normal and accidental conditions. All the diagnostics, whether or not pumped, incorporate penetration of the vacuum boundary (i.e. window assembly, vacuum feedthrough etc.) and demountable joints. Monitored guard volumes are provided for all elements of the vacuum boundary that are judged to be vulnerable by virtue of their construction, material, load specification etc. Standard arrangements are made for their construction and for the monitoring, evacuating and leak testing of these volumes. Diagnostic systems are incorporated at more than 20 ports on ITER. This paper will describe typical and particular arrangements of pumped diagnostic and monitored guard volume. The status of the diagnostic vacuum systems, which are at the start of their detailed design, will be outlined and the specific features of the vacuum systems in ports and extensions

  3. Technical specification for vacuum systems

    Energy Technology Data Exchange (ETDEWEB)

    Khaw, J. (ed.)

    1987-01-01

    The vacuum systems at the Stanford Linear Accelerator Center (SLAC) are primarily of all-metal construction and operate at pressures from 10/sup -5/ to 10/sup -11/ Torr. The primary gas loads during operation result from thermal desorption and beam-induced desorption from the vacuum chamber walls. These desorption rates can be extremely high in the case of hydrocarbons and other contaminants. These specifications place a major emphasis on eliminating contamination sources. The specifications and procedures have been written to insure the cleanliness and vacuum integrity of all SLAC vacuum systems, and to assist personnel involved with SLAC vacuum systems in choosing and designing components that are compatible with existing systems and meet the quality and reliability of SLAC vacuum standards. The specification includes requirements on design, procurement, fabrication, chemical cleaning, clean room practices, welding and brazing, helium leak testing, residual gas analyzer testing, bakeout, venting, and pumpdown. Also appended are specifications regarding acceptable vendors, isopropyl alcohol, bakeable valve cleaning procedure, mechanical engineering safety inspection, notes on synchrotron radiation, and specifications of numerous individual components. (LEW)

  4. p-Si(1 1 1):H/ionic liquid interface investigated through a combination of electrochemical measurements and reflection high energy electron diffraction surface analysis in vacuum

    Science.gov (United States)

    Watanabe, Ko; Maruyama, Shingo; Matsumoto, Yuji

    2016-07-01

    A combination study of electrochemical measurements and reflection high energy electron diffraction (RHEED) surface analysis experiments in a vacuum was first demonstrated to characterize a p-Si(1 1 1):H/ionic liquid interface. Mott-Schottky plot analysis was made to successfully not only evaluate the acceptor density and flat band potential of the p-Si(1 1 1):H, but also get some insight into its surface states. Furthermore, the electric double layer capacitance and specific adsorption properties at the IL/Si(1 1 1):H interface as well as the electrochemical interface stability will be discussed in this paper.

  5. Study of semi-transparent conductive layers for the realization of high quantum efficiency transmission mode CsI photocathodes for vacuum photodetectors

    Science.gov (United States)

    Barbato, F. C. T.; Valentini, A.; Casamassima, G.; Campajola, L.; Di Capua, F.

    2017-07-01

    We worked on the R&D of an innovative photodetector, the Vacuum Silicon Photomultiplier Tube (VSiPMT). The VSiPMT is composed by a photocathode and a solid state amplification stage. A semi-transparent conductive layer is necessary to supply voltage and to obtain a highly efficient CsI photocathode. Since the literature is poor on this topic we performed a systematic and detailed study of a set of semi-transparent conductive layers, made by different material and thickness. A CsI photocathode was evaporated on each sample. The impact of the semi-transparent conductive layer on the quantum efficiency of the photocathode is discussed.

  6. Advanced light source vacuum policy and vacuum guidelines for beamlines and experiment endstations

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Z.

    1995-08-01

    The purpose of this document is to: (1) Explain the ALS vacuum policy and specifications for beamlines and experiment endstations. (2) Provide guidelines related to ALS vacuum policy to assist in designing beamlines which are in accordance with ALS vacuum policy. This document supersedes LSBL-116. The Advanced Light Source is a third generation synchrotron radiation source whose beam lifetime depends on the quality of the vacuum in the storage ring and the connecting beamlines. The storage ring and most of the beamlines share a common vacuum and are operated under ultra-high-vacuum (UHV) conditions. All endstations and beamline equipment must be operated so as to avoid contamination of beamline components, and must include proper safeguards to protect the storage ring vacuum from an accidental break in the beamline or endstation vacuum systems. The primary gas load during operation is due to thermal desorption and electron/photon induced desorption of contaminants from the interior of the vacuum vessel and its components. The desorption rates are considerably higher for hydrocarbon contamination, thus considerable emphasis is placed on eliminating these sources of contaminants. All vacuum components in a beamline and endstation must meet the ALS vacuum specifications. The vacuum design of both beamlines and endstations must be approved by the ALS Beamline Review Committee (BRC) before vacuum connections to the storage ring are made. The vacuum design is first checked during the Beamline Design Review (BDR) held before construction of the beamline equipment begins. Any deviation from the ALS vacuum specifications must be approved by the BRC prior to installation of the equipment on the ALS floor. Any modification that is incorporated into a vacuum assembly without the written approval of the BRC is done at the user`s risk and may lead to rejection of the whole assembly.

  7. Advanced light source vacuum policy and vacuum guidelines for beamlines and experiment endstations

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Z.

    1995-08-01

    The purpose of this document is to: (1) Explain the ALS vacuum policy and specifications for beamlines and experiment endstations. (2) Provide guidelines related to ALS vacuum policy to assist in designing beamlines which are in accordance with ALS vacuum policy. This document supersedes LSBL-116. The Advanced Light Source is a third generation synchrotron radiation source whose beam lifetime depends on the quality of the vacuum in the storage ring and the connecting beamlines. The storage ring and most of the beamlines share a common vacuum and are operated under ultra-high-vacuum (UHV) conditions. All endstations and beamline equipment must be operated so as to avoid contamination of beamline components, and must include proper safeguards to protect the storage ring vacuum from an accidental break in the beamline or endstation vacuum systems. The primary gas load during operation is due to thermal desorption and electron/photon induced desorption of contaminants from the interior of the vacuum vessel and its components. The desorption rates are considerably higher for hydrocarbon contamination, thus considerable emphasis is placed on eliminating these sources of contaminants. All vacuum components in a beamline and endstation must meet the ALS vacuum specifications. The vacuum design of both beamlines and endstations must be approved by the ALS Beamline Review Committee (BRC) before vacuum connections to the storage ring are made. The vacuum design is first checked during the Beamline Design Review (BDR) held before construction of the beamline equipment begins. Any deviation from the ALS vacuum specifications must be approved by the BRC prior to installation of the equipment on the ALS floor. Any modification that is incorporated into a vacuum assembly without the written approval of the BRC is done at the user`s risk and may lead to rejection of the whole assembly.

  8. A high-Q resonant pressure microsensor with through-glass electrical interconnections based on wafer-level MEMS vacuum packaging.

    Science.gov (United States)

    Luo, Zhenyu; Chen, Deyong; Wang, Junbo; Li, Yinan; Chen, Jian

    2014-12-16

    This paper presents a high-Q resonant pressure microsensor with through-glass electrical interconnections based on wafer-level MEMS vacuum packaging. An approach to maintaining high-vacuum conditions by integrating the MEMS fabrication process with getter material preparation is presented in this paper. In this device, the pressure under measurement causes a deflection of a pressure-sensitive silicon square diaphragm, which is further translated to stress build up in "H" type doubly-clamped micro resonant beams, leading to a resonance frequency shift. The device geometries were optimized using FEM simulation and a 4-inch SOI wafer was used for device fabrication, which required only three photolithographic steps. In the device fabrication, a non-evaporable metal thin film as the getter material was sputtered on a Pyrex 7740 glass wafer, which was then anodically bonded to the patterned SOI wafer for vacuum packaging. Through-glass via holes predefined in the glass wafer functioned as the electrical interconnections between the patterned SOI wafer and the surrounding electrical components. Experimental results recorded that the Q-factor of the resonant beam was beyond 22,000, with a differential sensitivity of 89.86 Hz/kPa, a device resolution of 10 Pa and a nonlinearity of 0.02% F.S with the pressure varying from 50 kPa to 100 kPa. In addition, the temperature drift coefficient was less than -0.01% F.S/°C in the range of -40 °C to 70 °C, the long-term stability error was quantified as 0.01% F.S over a 5-month period and the accuracy of the microsensor was better than 0.01% F.S.

  9. A High-Q Resonant Pressure Microsensor with Through-Glass Electrical Interconnections Based on Wafer-Level MEMS Vacuum Packaging

    Directory of Open Access Journals (Sweden)

    Zhenyu Luo

    2014-12-01

    Full Text Available This paper presents a high-Q resonant pressure microsensor with through-glass electrical interconnections based on wafer-level MEMS vacuum packaging. An approach to maintaining high-vacuum conditions by integrating the MEMS fabrication process with getter material preparation is presented in this paper. In this device, the pressure under measurement causes a deflection of a pressure-sensitive silicon square diaphragm, which is further translated to stress build up in “H” type doubly-clamped micro resonant beams, leading to a resonance frequency shift. The device geometries were optimized using FEM simulation and a 4-inch SOI wafer was used for device fabrication, which required only three photolithographic steps. In the device fabrication, a non-evaporable metal thin film as the getter material was sputtered on a Pyrex 7740 glass wafer, which was then anodically bonded to the patterned SOI wafer for vacuum packaging. Through-glass via holes predefined in the glass wafer functioned as the electrical interconnections between the patterned SOI wafer and the surrounding electrical components. Experimental results recorded that the Q-factor of the resonant beam was beyond 22,000, with a differential sensitivity of 89.86 Hz/kPa, a device resolution of 10 Pa and a nonlinearity of 0.02% F.S with the pressure varying from 50 kPa to 100 kPa. In addition, the temperature drift coefficient was less than −0.01% F.S/°C in the range of −40 °C to 70 °C, the long-term stability error was quantified as 0.01% F.S over a 5-month period and the accuracy of the microsensor was better than 0.01% F.S.

  10. A High-Q Resonant Pressure Microsensor with Through-Glass Electrical Interconnections Based on Wafer-Level MEMS Vacuum Packaging

    Science.gov (United States)

    Luo, Zhenyu; Chen, Deyong; Wang, Junbo; Li, Yinan; Chen, Jian

    2014-01-01

    This paper presents a high-Q resonant pressure microsensor with through-glass electrical interconnections based on wafer-level MEMS vacuum packaging. An approach to maintaining high-vacuum conditions by integrating the MEMS fabrication process with getter material preparation is presented in this paper. In this device, the pressure under measurement causes a deflection of a pressure-sensitive silicon square diaphragm, which is further translated to stress build up in “H” type doubly-clamped micro resonant beams, leading to a resonance frequency shift. The device geometries were optimized using FEM simulation and a 4-inch SOI wafer was used for device fabrication, which required only three photolithographic steps. In the device fabrication, a non-evaporable metal thin film as the getter material was sputtered on a Pyrex 7740 glass wafer, which was then anodically bonded to the patterned SOI wafer for vacuum packaging. Through-glass via holes predefined in the glass wafer functioned as the electrical interconnections between the patterned SOI wafer and the surrounding electrical components. Experimental results recorded that the Q-factor of the resonant beam was beyond 22,000, with a differential sensitivity of 89.86 Hz/kPa, a device resolution of 10 Pa and a nonlinearity of 0.02% F.S with the pressure varying from 50 kPa to 100 kPa. In addition, the temperature drift coefficient was less than −0.01% F.S/°C in the range of −40 °C to 70 °C, the long-term stability error was quantified as 0.01% F.S over a 5-month period and the accuracy of the microsensor was better than 0.01% F.S. PMID:25521385

  11. Ultra-High-Vacuum Problem for 200 keV Polarized Electron Gun with NEA-GaAs Photocathode

    CERN Document Server

    Nakanishi, T; Kuwahara, M; Naniwa, K; Okumi, S; Yamamoto, M; Yamamoto, N; Yasui, K

    2004-01-01

    For a polarized electron source based on photoemission from GaAs, a NEA (Negative Electron Affinity) surface makes an indispensable role to extract polarized electrons in conduction band into vacuum. The NEA surface is also considered as a best surface to provide a beam with a minimum initial beam-emittance. However, the NEA surface state is realized by a mono-layer of electric dipole moment (that is Ga(-)-Cs(+)) formed at the surface and thus it is easily degraded by desorption of harmful residual gas, desorption of harmful gas created by field emission from HV-cathodes and ion back-bombardment. In order to reduce the effects of (a) and (c), extremely good UHV is required. Presently total pressure of 4·10-12

  12. High risk of fistula formation in vacuum-assisted closure therapy in patients with open abdomen due to secondary peritonitis-a retrospective analysis.

    Science.gov (United States)

    Mintziras, Ioannis; Miligkos, Michael; Bartsch, Detlef Klaus

    2016-08-01

    The aim of this study was to evaluate the efficacy of vacuum-assisted closure therapy in patients with open abdomen due to secondary peritonitis and to identify possible risk factors of fistula formation. The hospital OPS-database (time period 2005-2014) was searched to identify patients treated with an open abdomen due to secondary peritonitis, who underwent vacuum-assisted closure therapy. Medical records were retrospectively analyzed for patients' characteristics, cause of peritonitis, duration of vacuum therapy, number of relaparotomies, fascial closure rates, and risk factors of fistula formation. Forty-three patients (19 male, 24 female) with a median age of 65 years (range 24-90 years) were identified. The major cause of secondary peritonitis was anastomotic leakage after intestinal anastomosis or bowel perforation, the median APACHE II score was 11. Median duration of VAC treatment was 12 days (range 3-88 days). Twenty of 43 (47 %) patients died from septic complications. Delayed fascial closure was obtained by suturing in 20 of 43 patients (47 %). Overall 16 of 43 (37 %) patients developed enteroatmospheric fistulas. Re-explorations after starting VAC treatment and duration of VAC therapy were significantly associated with the occurrence of enteroatmospheric fistulas (p analysis determined the optimal duration of VAC therapy to reduce the risk of fistula formation at 13 days. Long-term VAC treatment of patients with an open abdomen due to secondary peritonitis results in a relatively low fascial closure rate and a high risk of fistula formation.

  13. RFQ Vacuum brazing at CERN

    CERN Document Server

    Mathot, S

    2008-01-01

    The aim of this paper is to describe the vacuum brazing procedure used at CERN for the brazing of Radio Frequency Quadrupole (RFQ). The RFQ is made of high precision machined OFE copper pieces assembled together. Vacuum brazing is one of the most promising techniques used to join the individual components leading to vacuum tightness and high precision alignment. The RFQ modules brazed at CERN are made of four 100 or 120 cm long vanes (two major and two minor vanes). Our brazing procedure consists of two steps. The first step involves the brazing of the four vanes in a horizontal position. The second step consists of brazing the vacuum stainless steel flanges to the copper structure in a vertical position. The paper describes the problems encountered with the alignment and the vacuum tightness. The difficulties related to the stress relaxation of the machined copper pieces during the brazing heat treatment are discussed. In addition, the solutions developed to improve the alignment of the brazed RFQ’s are...

  14. Study of impurity distribution in mechanically polished, chemically treated and ultra-high vacuum degassed pure Niobium samples using TOFSIMS technique

    CERN Document Server

    Bose, A

    2015-01-01

    The performance of Superconducting radio frequency cavities (SCRF) are highly dependent on the surface treatment processes, which in turn is influenced by the chemistry within the penetration depth of Niobium (Nb). The present study analyses various impurities within the RF penetration depth (~50nm) of Nb samples treated by SCRF cavity processing techniques like colloidal silica polishing (simulating centrifugal barrel polishing), buffer chemical polishing (BCP), high pressure rinsing (HPR) and degassing under ultra high vacuum (UHV) condition at 600{\\deg}C for 10hrs. Various modes of Time of flight secondary ion mass spectrometry (TOFSIMS) technique was employed to study the effect of the above treatments on the vast spectrum of impurities that include interstitials, hydrocarbons, oxides, acidic residuals, reaction products and metallic impurities. UHV degassing treatment was the only treatment capable of reducing hydrogen contamination, but, it led to extensive oxygen, carbon and metallic impurities in the ...

  15. Vacuum-sealed silicon micromachined pressure sensors

    Energy Technology Data Exchange (ETDEWEB)

    Esashi, Masayoshi [Tohoku Univ., Aobaku, Sendai (Japan); Sugiyama, Susumu [Ritsumeikan Univ., Kusatsu, Shiga (Japan); Ikeda, Kyoichi [Yokogawa Electric Corp., Nagano (Japan); Wang, Y. [Zhejian Univ., Hangzhou (China); Miyashita, Haruzo [Anelva Corp., Yamanashi (Japan)

    1998-08-01

    Considerable progress in silicon pressure sensors has been made in recent years. This paper discusses three types of vacuum-sealed silicon micromachined pressure sensors that represent the present state of the art in this important area. The devices are a capacitive vacuum sensor, a surface-micromachined microdiaphragm pressure sensor, and a resonant pressure sensor. Vacuum sealing for these devices is accomplished using anodic bonding, films deposited using low-pressure chemical vapor deposition, and thermal out-diffusion of hydrogen, respectively. These sensors emphasize high sensitivity; small size, and excellent stability, respectively. The silicon-diaphragm vacuum sensor uses electrostatic force balancing to achieve a wide pressure measurement range.

  16. A 'NanoSuit' surface shield successfully protects organisms in high vacuum: observations on living organisms in an FE-SEM.

    Science.gov (United States)

    Takaku, Yasuharu; Suzuki, Hiroshi; Ohta, Isao; Tsutsui, Takami; Matsumoto, Haruko; Shimomura, Masatsugu; Hariyama, Takahiko

    2015-03-01

    Although extremely useful for a wide range of investigations, the field emission scanning electron microscope (FE-SEM) has not allowed researchers to observe living organisms. However, we have recently reported that a simple surface modification consisting of a thin extra layer, termed 'NanoSuit', can keep organisms alive in the high vacuum (10(-5) to 10(-7) Pa) of the SEM. This paper further explores the protective properties of the NanoSuit surface-shield. We found that a NanoSuit formed with the optimum concentration of Tween 20 faithfully preserves the integrity of an organism's surface without interfering with SEM imaging. We also found that electrostatic charging was absent as long as the organisms were alive, even if they had not been coated with electrically conducting materials. This result suggests that living organisms possess their own electrical conductors and/or rely on certain properties of the surface to inhibit charging. The NanoSuit seems to prolong the charge-free condition and increase survival time under vacuum. These findings should encourage the development of more sophisticated observation methods for studying living organisms in an FE-SEM.

  17. Thermal Gradient During Vacuum-Deposition Dramatically Enhances Charge Transport in Organic Semiconductors: Toward High-Performance N-Type Organic Field-Effect Transistors.

    Science.gov (United States)

    Kim, Joo-Hyun; Han, Singu; Jeong, Heejeong; Jang, Hayeong; Baek, Seolhee; Hu, Junbeom; Lee, Myungkyun; Choi, Byungwoo; Lee, Hwa Sung

    2017-03-09

    A thermal gradient distribution was applied to a substrate during the growth of a vacuum-deposited n-type organic semiconductor (OSC) film prepared from N,N'-bis(2-ethylhexyl)-1,7-dicyanoperylene-3,4:9,10-bis(dicarboxyimide) (PDI-CN2), and the electrical performances of the films deployed in organic field-effect transistors (OFETs) were characterized. The temperature gradient at the surface was controlled by tilting the substrate, which varied the temperature one-dimensionally between the heated bottom substrate and the cooled upper substrate. The vacuum-deposited OSC molecules diffused and rearranged on the surface according to the substrate temperature gradient, producing directional crystalline and grain structures in the PDI-CN2 film. The morphological and crystalline structures of the PDI-CN2 thin films grown under a vertical temperature gradient were dramatically enhanced, comparing with the structures obtained from either uniformly heated films or films prepared under a horizontally applied temperature gradient. The field effect mobilities of the PDI-CN2-FETs prepared using the vertically applied temperature gradient were as high as 0.59 cm(2) V(-1) s(-1), more than a factor of 2 higher than the mobility of 0.25 cm(2) V(-1) s(-1) submitted to conventional thermal annealing and the mobility of 0.29 cm(2) V(-1) s(-1) from the horizontally applied temperature gradient.

  18. Nanograting-based compact vacuum ultraviolet spectrometer and beam profiler for in situ characterization of high-order harmonic generation light sources.

    Science.gov (United States)

    Kornilov, Oleg; Wilcox, Russell; Gessner, Oliver

    2010-06-01

    A compact, versatile device for vacuum ultraviolet (VUV) beam characterization is presented. It combines the functionalities of a VUV spectrometer and a VUV beam profiler in one unit and is entirely supported by a standard DN200 CF flange. The spectrometer employs a silicon nitride transmission nanograting in combination with a microchannel plate-based imaging detector. This enables the simultaneous recording of wavelengths ranging from 10 to 80 nm with a resolution of 0.25-0.13 nm. Spatial beam profiles with diameters up to 10 mm are imaged with 0.1 mm resolution. The setup is equipped with an in-vacuum translation stage that allows for in situ switching between the spectrometer and beam profiler modes and for moving the setup out of the beam. The simple, robust design of the device is well suited for nonintrusive routine characterization of emerging laboratory- and accelerator-based VUV light sources. Operation of the device is demonstrated by characterizing the output of a femtosecond high-order harmonic generation light source.

  19. Physisorption of ammonia on AISI 304L stainless steel at different surface temperature under high vacuum conditions

    Directory of Open Access Journals (Sweden)

    A. de Castro

    2016-12-01

    Full Text Available The physisorption of ammonia molecules (sticking on the walls of a stainless steel pipe (AISI 304L has been studied at different wall temperatures (323-473K. The total amount of ammonia that is retained on the walls, once equilibrium is reached, has been measured by differentially-pumped mass spectrometry in gas exposure laboratory experiments. The results show ammonia retentions in the range of μg/cm2 resulting in a multilayer adsorption with lower amounts of stuck ammonia at higher temperatures of the stainless steel surface. The sticking coefficient follows an exponential decay evolution with time. The activation energy of the process has been estimated by an Arrhenius fit, assuming that the characteristic time for this decay is inversely proportional to the kinetic adsorption constant. A value of 0.15eV per ammonia molecule has been obtained, being in agreement with nominal values for the physisorption of small molecules or atoms (CO, N2, Ar… that can be found in the specialized literature. The implication of these results in the possible extrapolation to the ITER vacuum system under nitrogen seeded plasma operation is also addressed.

  20. Adding high time resolution to charge-state-specific ion energy measurements for pulsed copper vacuum arc plasmas

    CERN Document Server

    Tanaka, Koichi; Zhou, Xue; Anders, André

    2015-01-01

    Charge-state-resolved ion energy-time-distributions of pulsed Cu arc plasma were obtained by using direct (time dependent) acquisition of the ion detection signal from a commercial ion mass-per-charge and energy-per-charge analyzer. We find a shift of energies of Cu2+, Cu3+ and Cu4+ ions to lower values during the first few hundred microseconds after arc ignition, which is evidence for particle collisions in the plasma. The generation of Cu1+ ions in the later part of the pulse, measured by the increase of Cu1+ signal intensity and an associated slight reduction of the mean charge state point to charge exchange reactions between ions and neutrals. At the very beginning of the pulse, when the plasma expands into vacuum and the plasma potential strongly fluctuates, ions with much higher energy (over 200 eV) were observed. Early in the pulse, the ion energies observed are approximately proportional to the ion charge state, and we conclude that the acceleration mechanism is primarily based on acceleration in an e...

  1. Of vacuum and gas

    CERN Multimedia

    Katarina Anthony

    2015-01-01

    A new LHCb programme is delving into uncharted waters for the LHC: exploring how protons interact with noble gases inside the machine pipe. While, at first glance, it may sound risky for the overall quality of the vacuum in the machine, the procedure is safe and potentially very rich in rewards. The results could uncover the high-energy helium-proton cross-section (with all the implications thereof), explore new boundaries of the quark-gluon plasma and much more.   As the beam passes through LHCb, interactions with neon gas allow the experiment to measure the full beam profile. In this diagram, beam 1 (blue) and beam 2 (red) are measured by the surrounding VELO detector. It all begins with luminosity. In 2011, LHCb set out to further improve its notoriously precise measurements of the beam profile, using the so-called Beam-Gas Imaging (BGI) method. BGI does exactly what it says on the tin: a small amount of gas is inserted into the vacuum, increasing the rate of collisions around the interaction ...

  2. Impact of high pressure treatment and intramuscular fat content on colour changes and protein and lipid oxidation in sliced and vacuum-packaged Iberian dry-cured ham.

    Science.gov (United States)

    Fuentes, Verónica; Utrera, Mariana; Estévez, Mario; Ventanas, Jesús; Ventanas, Sonia

    2014-08-01

    The effect of high hydrostatic pressure (HHP) (600MPa) and intramuscular fat content (IMF) on colour parameters and oxidative stability of lipids and proteins in sliced vacuum-packaged Iberian dry-cured ham during refrigerated storage (120 days at 2°C) was investigated. Several studies have investigated the influence of HHP on lipid oxidation of meat products. However, its effects on protein carbonylation, as also the influence of IMF content on this carbonylation are poorly understood. HHP treatment had a significant effect on lean lightness after 0 and 120 days of storage while IMF content increased lightness and yellowness over time. Regarding oxidative stability, the effect of HHP treatment depended on IMF content samples with a high IMF having greater lipid instability while samples with a low IMF underwent more protein carbonylation.

  3. Direct growth of Ge1-xSnx films on Si using a cold-wall ultra-high-vacuum chemical-vapor-deposition system

    Directory of Open Access Journals (Sweden)

    Aboozar eMosleh

    2015-04-01

    Full Text Available Germanium tin alloys were grown directly on Si substrate at low temperatures using a cold-wall ultra-high vacuum chemical vapor deposition system. Epitaxial growth was achieved by adopting commercial gas precursors of germane and stannic chloride without any carrier gases. The X-ray diffraction analysis showed the incorporation of Sn and that the Ge1-xSnx films are fully epitaxial and strain relaxed. Tin incorporation in the Ge matrix was found to vary from 1% to 7%. The scanning electron microscopy images and energy dispersive X-ray spectra maps show uniform Sn incorporation and continuous film growth. Investigation of deposition parameters shows that at high flow rates of stannic chloride the films were etched due to the production of HCl. The photoluminescence study shows the reduction of bandgap from 0.8 eV to 0.55 eV as a result of Sn incorporation.

  4. Vacuum-sealed casting process under pressure

    Institute of Scientific and Technical Information of China (English)

    LI Chen-xi; GUO Tai-ming; WU Chun-jing; WANG Hong

    2006-01-01

    A new casting method, the vacuum-sealed mold casting under pressure, has been developed, and thin wall iron castings with high precision and smooth surface have been produced successfully with this casting method. The experimental results show that the liquid iron has a very excellent filling ability because a high negative pressure is formed in the mold cavity during filling process. The vacuum-sealed mold under pressure has very high compressive strength greater than 650 kPa, which is 3-4 times as high as that of the molds produced by high-pressure molding process or vacuum-sealed molding process.

  5. High-resolution threshold photoelectron study of the propargyl radical by the vacuum ultraviolet laser velocity-map imaging method

    Science.gov (United States)

    Gao, Hong; Xu, Yuntao; Yang, Lei; Lam, Chow-Shing; Wang, Hailing; Zhou, Jingang; Ng, C. Y.

    2011-12-01

    By employing the vacuum ultraviolet (VUV) laser velocity-map imaging (VMI) photoelectron scheme to discriminate energetic photoelectrons, we have measured the VUV-VMI-threshold photoelectrons (VUV-VMI-TPE) spectra of propargyl radical [C3H3({tilde X}{}^2B_1)] near its ionization threshold at photoelectron energy bandwidths of 3 and 7 cm-1 (full-width at half-maximum, FWHM). The simulation of the VUV-VMI-TPE spectra thus obtained, along with the Stark shift correction, has allowed the determination of a precise value 70 156 ± 4 cm-1 (8.6982 ± 0.0005 eV) for the ionization energy (IE) of C3H3. In the present VMI-TPE experiment, the Stark shift correction is determined by comparing the VUV-VMI-TPE and VUV laser pulsed field ionization-photoelectron (VUV-PFI-PE) spectra for the origin band of the photoelectron spectrum of the {tilde X}^ + {- tilde X} transition of chlorobenzene. The fact that the FWHMs for this origin band observed using the VUV-VMI-TPE and VUV-PFI-PE methods are nearly the same indicates that the energy resolutions achieved in the VUV-VMI-TPE and VUV-PFI-PE measurements are comparable. The IE(C3H3) value obtained based on the VUV-VMI-TPE measurement is consistent with the value determined by the VUV laser PIE spectrum of supersonically cooled C3H3({tilde X}{}^2B_1) radicals, which is also reported in this article.

  6. Simulations and Vacuum Tests of a CLIC Accelerating Structure

    CERN Document Server

    Garion, C

    2011-01-01

    The Compact LInear Collider, under study, is based on room temperature high gradient structures. The vacuum specificities of these cavities are low conductance, large surface areas and a non-baked system. The main issue is to reach UHV conditions (typically 10-7 Pa) in a system where the residual vacuum is driven by water outgassing. A finite element model based on an analogy thermal/vacuum has been built to estimate the vacuum profile in an accelerating structure. Vacuum tests are carried out in a dedicated set-up, the vacuum performances of different configurations are presented and compared with the predictions.

  7. Improved anchoring of SSS with vacuum barrier to avoid displacement

    CERN Document Server

    Capatina, O; Foreste, A; Parma, V; Renaglia, T; Quesnel, J

    2009-01-01

    As presented in the previous speech, the incident in sector 3-4 of the LHC caused a high pressure build-up inside the cryostat insulation vacuum resulting in high longitudinal forces acting on the insulation vacuum barriers. This resulted in braking floor and floor fixations of the SSS with vacuum barrier. The strategy of improving anchoring of SSS with vacuum barrier to avoid displacement is presented and discussed.

  8. Vacuum Energy: Myths and Reality

    OpenAIRE

    Volovik, G. E.

    2006-01-01

    We discuss the main myths related to the vacuum energy and cosmological constant, such as: ``unbearable lightness of space-time''; the dominating contribution of zero point energy of quantum fields to the vacuum energy; non-zero vacuum energy of the false vacuum; dependence of the vacuum energy on the overall shift of energy; the absolute value of energy only has significance for gravity; the vacuum energy depends on the vacuum content; cosmological constant changes after the phase transition...

  9. Physical Vacuum in Superconductors

    CERN Document Server

    de Matos, Clovis Jacinto

    2009-01-01

    Although experiments carried out by Jain et al. showed that the Cooper pairs obey the strong equivalence principle, The measurement of the Cooper pairs inertial mass by Tate et al. revealed an anomalous excess of mass. In the present paper we interpret these experimental results in the framework of an electromagnetic model of dark energy for the superconductors' vacuum. We argue that this physical vacuum is associated with a preferred frame. Ultimately from the conservation of energy for Cooper pairs we derive a model for a variable vacuum speed of light in the superconductors physical vacuum in relation with a possible breaking of the weak equivalence principle for Cooper pairs.

  10. Updates of the KArLE Experiment: New Libs Calibration Under High Vacuum for the Quantification of Potassium in Basalt for In Situ Geochronology

    Science.gov (United States)

    Devismes, D.; Cohen, B. A.; Li, Z.-H.; Miller, J. S.

    2014-01-01

    In planetary exploration, in situ absolute geochronology is one of the main important measurements that needs to be accomplished. Until now, on Mars, the age of the surface is only determined by crater density counting, which gives relative ages. These ages can have a lot of uncertainty as they depend on many parameters. More than that, the curves must be ties to absolute ages. Thus far, only the lost lander Beagle 2 was designed to conduct absolute geochronology measurements, though some recent attempts using MSL Curiosity show that this investigation is feasible and should be strongly encouraged for future flight. Experimental: The Potassium (K)-Argon Laser Experiment (KArLE) is being developed at MSFC through the NASA Planetary Instrument Definition and Development Program (PIDDP). The goal of this experiment is to provide in situ geochronology based on the K-Ar method. A laser ablates a rock under high vacuum, creating a plasma which is sensed by an optical spectrometer to do Laser Induced Breakdown Spectroscopy (LIBS). The ablated material frees gases, including radiogenic 40Ar,which is measured by a mass spectrometer (MS). As the potassium is a content and the 40Ar is a quantity, the ablated mass needed in order to relate them. The mass is given by the product of the ablated volume by the density of this material. So we determine the mineralogy of the ablated material with the LIBS spectra and images and calculate its density. The volume of the pit is measured by using microscopy. LIBS measurement of K under high vacuum: Three independant projects [1, 2, 3] including KArLE, are developing geochronological instruments based on this LA-LIBS-MS method. Despite several differences in their setup, all of them have validated the methods with analyses and ages. However, they all described difficulties with the LIBS measurements of K [3,4]. At ambient pressure, the quantification of K by LIBS on geological materials can be accurate [5]. However the protocol of the LA

  11. A compact Ultra-High Vacuum (UHV) compatible instrument for time of flight-energy measurements of slow heavy reaction products

    CERN Document Server

    Kuznetsov, A V; Westerberg, L; Lyapin, V G; Aleklett, K; Loveland, W; Bondorf, J P; Jakobsson, B; Whitlow, H J; El-Bouanani, M

    2000-01-01

    A compact Ultra-High Vacuum (UHV) compatible instrument for time of flight-energy measurements of slow heavy reaction products from nuclear reactions has been designed and tested at the CELSIUS storage ring in Uppsala. The construction is based on MicroChannel Plate (MCP) time detectors of the electron mirror type and silicon p-i-n diodes, and permits the detectors to be stacked side-by-side to achieve large solid angle coverage. This kind of telescope measures the Time of Flight (ToF) and Energy (E) of the particle from which one can reconstruct mass. The combination of an ultra-thin cluster gas-jet target and thin carbon emitter foils allows one to measure heavy residues down to an energy of approx 35 keV/nucleon from the interactions of 400 MeV/nucleon sup 1 sup 6 O with sup n sup a sup t Xe gas targets.

  12. Potential method for gas production: high temperature co-pyrolysis of lignite and sewage sludge with vacuum reactor and long contact time.

    Science.gov (United States)

    Yang, Xiao; Yuan, Chengyong; Xu, Jiao; Zhang, Weijiang

    2015-03-01

    Lignite and sewage sludge were co-pyrolyzed in a vacuum reactor with high temperature (900°C) and long contact time (more than 2h). Beneficial synergetic effect on gas yield was clearly observed. Gas yield of blend fuel was evidently higher than that of both parent fuels. The gas volume yield, gas lower heating value (LHV), fixed carbon conversion and H2/CO ratio were 1.42 Nm(3)/kg(blend fuel), 10.57 MJ/Nm(3), 96.64% and 0.88% respectively, which indicated this new method a feasible one for gas production. It was possible that sewage sludge acted as gasification agents (CO2 and H2O) and catalyst (alkali and alkaline earth metals) provider during co-pyrolysis, promoting CO2-char and H2O-char gasification which, as a result, invited the improvement of gas volume yield, gas lower heating value and fixed carbon conversion.

  13. 真空引纸器在高速纸机中的运用%Application of vacuum threading belt in high speed paper machines

    Institute of Scientific and Technical Information of China (English)

    欧志勇

    2013-01-01

    The structure, principle, adjustment and maintenance for vacuum threading facilities from two type of treading equipment in high speed paper machine were introduced. From safety reliability ideas and hommization management, it was discussed that the old paper machines in domestic are transformed so as to improve threading automation.%  介绍两种运用在高速纸机中的真空引纸设备的结构、操作原理、调整及维修,并从安全可靠理念、人性化管理出发,探讨在国内的一些老旧纸机相关部位方面进行改造安装、提高引纸的自动化程度。

  14. In situ studies of the atomic layer deposition of thin HfO{sub 2} dielectrics by ultra high vacuum atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Kolanek, Krzysztof, E-mail: kolanek@tu-cottbus.d [Brandenburg University of Technology, Department of Applied Physics and Sensors, Konrad-Wachsmann-Allee 17, 03046 Cottbus (Germany); Tallarida, Massimo; Karavaev, Konstantin; Schmeisser, Dieter [Brandenburg University of Technology, Department of Applied Physics and Sensors, Konrad-Wachsmann-Allee 17, 03046 Cottbus (Germany)

    2010-06-01

    We studied in situ the initial stages of atomic layer deposition (ALD) of HfO{sub 2} by an ultra high vacuum atomic force microscope working in frequency-modulation mode. The ALD cycles, made by using tetrakis-di-methyl-amido-Hf and water as precursors, were performed on the Si(001)/SiO{sub 2} substrate maintained at 230 {sup o}C. After each ALD cycle we studied the influence of the HfO{sub 2} growth on the surface height histogram, the root mean square roughness, the surface fractal dimension and the autocorrelation function. This detailed analysis of the surface topography allowed us to confirm the completion of the first HfO{sub 2} layer after four ALD cycles.

  15. Absorption spectroscopy of xenon and ethylene-noble gas mixtures at high pressure: Towards Bose-Einstein condensation of vacuum ultraviolet photons

    CERN Document Server

    Wahl, Christian; Schmitt, Julian; Vewinger, Frank; Christopoulos, Stavros; Weitz, Martin

    2016-01-01

    Bose-Einstein condensation is a phenomenon well known for material particles as cold atomic gases, and this concept has in recent years been extended to photons confined in microscopic optical cavities. Essential for the operation of such a photon condensate is a thermalization mechanism that conserves the average particle number, as in the visible spectral regime can be realized by subsequent absorption re-emission processes in dye molecules. Here we report on the status of an experimental effort aiming at the extension of the concept of Bose-Einstein condensation of photons towards the vacuum ultraviolet spectral regime, with gases at high pressure conditions serving as a thermalization medium for the photon gas. We have recorded absorption spectra of xenon gas at up to 30 bar gas pressure of the $5p^6 - 5p^56s$ transition with a wavelength close to 147 nm. Moreover, spectra of ethylene noble gas mixtures between 155 and 180 nm wavelength are reported.

  16. Design and Development of the Telescope-deployment High-vacuum teleOperated Rover (THOR) in an Airless Body Environment

    CERN Document Server

    Womack, Chris; Kruger, Laura; DeGeorge, Kelsey; Tuan, Karynna; Burns, Jack

    2014-01-01

    The harsh environment on the lunar surface presents unique technological challenges for space exploration. This paper presents research on the design and development of the Tele- scope-deployment High-vacuum teleOperated Rover (THOR), currently being built and tested in the Lunar and Airless Bodies Simulator (LABS) facility at the University of Colorado Boulder. This rover is fabricated entirely out of cost-effective commercial off-the-shelf (COTS) components and materials. THOR can potentially survive for more than one simulated year in conditions similar to that of the lunar environment, demonstrating the successful initial results of a first phase research study on material and electronic survivability in an extreme environment such as the Moon.

  17. Mass flux response comparisons of a 200-MHz surface acoustic wave (SAW) resonator microbalance to a 15-MHz thermoelectric quartz crystal microbalance (TQCM) in a high-vacuum environment

    Science.gov (United States)

    Wallace, Donald A.; Bowers, William D.

    1994-10-01

    Using a 200 MHz Surface Acoustic Wave (SAW) resonator device as a high-vacuum molecular deposition microbalance, similar to a bulk quartz crystal microbalance (QCM), and an often-used 15 MHz thermoelectric QCM (TQCM), a comparison of various parameters was made during a high-vacuum outgassing experiment. The source of molecular outgassing was a bright aluminum foil which was cooled to liquid nitrogen temperature and alternately, to ambient temperature. The two sensors, the SAW QCM and the TQCM were placed next to each other and viewed only the aluminum foil. In this high-vacuum environment, a comparison between various parameters, i.e., mass sensitivity, long term drift rate, stability, thermal effects and dynamic range of the SAW and the TQCM, was obtained.

  18. Vacuum Birefringence as a Vacuum Emission Process

    CERN Document Server

    Karbstein, Felix

    2015-01-01

    We argue that the phenomenon of vacuum birefringence in strong inhomogeneous electromagnetic fields can be most efficiently analyzed in terms of a vacuum emission process. In this contribution, we exemplarily stick to the case of vacuum birefringence in a stationary perpendicularly directed, purely magnetic background field extending over a finite spatial extent. Similar field configurations are realized in the BMV and PVLAS experiments. We demonstrate that we can reproduce the conventional constant field result. Our focus is on effects which arise when the probe photons originate in the field free region, are directed towards the magnetic field region, and detected well after the interaction with the magnetic field has taken place, again at zero field.

  19. Abnormal piezoresponse behavior of Pb(Mg1/3Nb2/3)O3-30%PbTiO3 single crystal studied by high vacuum scanning force microscopy

    Institute of Scientific and Technical Information of China (English)

    ZENG Huarong; YIN Qingrui; LI Guorong; LUO Haosu; XU Zhenkui

    2003-01-01

    The piezoresponse behavior dependence of the Pb(Mg1/3Nb2/3)O3-30%PbTiO3 single crystal on the vacuum degree has been investigated by scanning force microscopy in the piezoresponse mode under high vacuum. Unusual piezo- response behavior related to the screening charges compensation mechanism is observed on the (111) crystal face. The significant piezoresponse degradation behavior with low piezoresponse signal under high vacuum is attributed to the instability of thepolarization state due to the insufficient compensation of the intrinsic screening charges for the polarization charges in PMN-30%PT single crystal. In contrast, the remarkable domain contrast of the sample at ambient pressure is owing to the dominant surface screening charges deriving from surface adsorption, which plays an important role in determining the stability of the domain behavior and in achieving the optimal properties.

  20. Cervical spine annulus vacuum.

    Science.gov (United States)

    Bohrer, S P; Chen, Y M

    1988-01-01

    Thirty-eight annulus vacuums in 27 patients were analyzed with regard to location, configuration, and associated vertebral abnormalities such as degenerative changes, absent and compressed anterosuperior vertebral body corners, and annulus calcification. It is concluded that most annulus vacuums are a degenerative phenomenon at the attachment of the annulus to bone. These vacuums may be associated with other degenerative changes such as osteophytes and annulus calcification. Vacuums have a strong association with compressed anterosuperior corners. These deformed corners are thought to be early osteophytes and may be related to previous trauma, a vertebra with an absent corner, and/or normal motion. Small annulus vacuums adjacent to vertebral corners with a normal appearance are more likely to result from acute trauma.

  1. ELETTRA vacuum system

    Science.gov (United States)

    Bernardini, M.

    1991-08-01

    A status report of the vacuum system of ELETTRA, the 2 GeV, 400 mA light source under construction in Trieste, will be described. The Vacuum project, presented at ``Synchrotron Radiation Vacuum Workshop'' at Riken (Japan 22-24 March 1990) and more recently at EVC-2, the European Vacuum Conference at Trieste (Italy 21-26 May 1990), is now in the phase of testing a prototype sector, which is 1/24 of the ring circumference. Details and some technological aspects of the fabrication will be reviewed together with the vacuum performances. Results of laboratory experiments on components, standard or not, allowed us to finalize the main choices in light of the general philosophy of the project and will be properly summarized.

  2. Cervical spine annulus vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Bohrer, S.P.; Chen, Y.M.

    1988-07-01

    Thirty-eight annulus vacuums in 27 patients were analyzed with regard to location, configuration, and associated vertebral abnormalities such as degenerative changes, absent and compressed anterosuperior vertebral body corners, and annulus calcification. It is concluded that most annulus vacuums are a degenerative phenomenon at the attachment of the annulus to bone. These vacuums may be associated with other degenerative changes such as osteophytes and annulus calcification. Vacuums have a strong association with compressed anterosuperior corners. These deformed corners are thought to be early osteophytes and may be related to previous trauma, a vertebra with an absent corner, and/or normal motion. Small annulus vacuums adjacent to vertebral corners with a normal appearance are more likely to result from acute trauma.

  3. Vacuum controls and interlocks

    CERN Document Server

    Strubin, P

    2007-01-01

    The vacuum control system is, in most cases, a subset of the general control system of an accelerator. As such, it shares the architecture and communication infrastructure of the main control system. Considered as a ‘slow process’ to control in the frame of accelerators, the vacuum control system can be built using commercial industrial controllers (PLCs). A data driven approach allows for changes in configuration without changing the software code but at the expense of a solid database. Modelling the equipment allows for easy adaptation of a variety of control units with the same functionality but different physical interfaces. It also allows for a uniform display of the available data and status values. Interlocks are required to protect the vacuum equipment itself against abnormal conditions, but also to protect other systems, like RF, which need a good vacuum to operate. They are an integral part of any vacuum control system.

  4. Instrument Description and Performance Evaluation of a High-Order Adaptive Optics System for the 1 m New Vacuum Solar Telescope at Fuxian Solar Observatory

    Science.gov (United States)

    Rao, Changhui; Zhu, Lei; Rao, Xuejun; Zhang, Lanqiang; Bao, Hua; Kong, Lin; Guo, Youming; Zhong, Libo; Ma, Xue'an; Li, Mei; Wang, Cheng; Zhang, Xiaojun; Fan, Xinlong; Chen, Donghong; Feng, Zhongyi; Gu, Naiting; Liu, Yangyi

    2016-12-01

    A high-order solar adaptive optics (AO) system including a fine tracking loop and a high-order wavefront correction loop has been installed at the 1 m New Vacuum Solar Telescope of the Fuxian Solar Observatory, in routine operation since 2016. The high-order wavefront correction loop consists of a deformable mirror with 151 actuators, a correlating Shack-Hartmann wavefront sensor with 102 subapertures of which the Absolute Difference Square Algorithm is used to extract the gradients, and a custom-built real-time controller based on a Field-Programmable Gate Array (FPGA) and multi-core Digital Signal Processor (DSP). The frame rate of the wavefront sensor is up to 3500 Hz and this is, to our knowledge, the fastest solar AO system. This AO system can work with a Fried parameter r 0, at the 500 nm wavelength, of larger than 3 cm. The first 65 modes of the Zernike aberrations can be efficiently corrected and the Strehl ratio of the corrected TiO image for the solar pore is superior to 0.75 with the Fried parameter r 0 larger than 10 cm. In this paper, the design of the system is described, and high-resolution solar observational images are presented. Furthermore, the performances of the AO system are evaluated according to the data recorded by the real-time controller.

  5. Vacuum Furnace - Integrated "Sub zero" Treatment

    Institute of Scientific and Technical Information of China (English)

    B. Zieger; Hubert Schulte

    2004-01-01

    The vacuum heat treatment with overpressure gas quenching is more and more accepted due to considerable advantages compared to the traditional oil and salt bath processes. Continuous further developments and new concepts like multi-directional cooling systems, a separate quenching chamber and "sub zero" systems lead towards an oxidation free and low distortion vacuum heat treatment for a broad range of parts and materials. Short and energy saving processes guarantee a high economic efficiency and environmental compatibility.The "sub zero" system which is integrated into the standard vacuum furnace achieves a heat treatment result with a high conversion of retained austenite in fully automatic hardening and tempering processes.

  6. 防止高速重轨钢真空喷溅的生产实践%Production practice for preventing vacuum splashing of high speed heavy rail

    Institute of Scientific and Technical Information of China (English)

    段光豪; 王光进; 朱志鹏

    2015-01-01

    The mechanism of high speed heavy rail splashing in the vacuumize process was analyzed,it was found that existing of oxidizing slag in vacuum chamber and rapid decreasing of vacuum degree were the main reasons for the splashing.According to the practical production,the improvement measures for controlling vacuum degree and slag deposition in vacuum chamber,optimizing driving gas mode,changing the time for adding carbon powder and ferromanganese were put forward,which obtained better effects.%对高速重轨钢在抽真空过程中发生喷溅的机理进行分析,发现真空室内含有氧化性积渣以及真空度的快速下降是导致喷溅的主要原因。结合生产实践,提出了控制真空度、真空室内积渣及优化驱动气体模式和碳粉、锰铁加入时间等改进措施,取得了较好的效果。

  7. Baking results of KSTAR vacuum vessel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. T.; Kim, Y. J.; Kim, K. M.; Im, D. S.; Joung, N. Y.; Yang, H. L.; Kim, Y. S.; Kwon, M. [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2009-05-15

    The Korea Superconducting Tokamak Advanced Research (KSTAR) is an advanced superconducting tokamak designed to establish a scientific and technological basis for an attractive fusion reactor. The fusion energy in the tokamak device is released through fusion reactions of light atoms such as deuterium or helium in hot plasma state, of which temperature reaches several hundreds of millions Celsius. The high temperature plasma is created in the vacuum vessel that provides ultra high vacuum status. Accordingly, it is most important for the vacuum condition to keep clean not only inner space but also surface of the vacuum vessel to make high quality plasma. There are two methods planned to clean the wall surface of the KSTAR vacuum vessel. One is surface baking and the other is glow discharge cleaning (GDC). To bake the vacuum vessel, De-Ionized (DI) water is heated to 130 .deg. C and circulated in the passage between double walls of the vacuum vessel (VV) in order to bake the surface. The GDC operation uses hydrogen and inert gas discharges. In this paper, general configuration and brief introduction of the baking result will be reported.

  8. High-temperature two-dimensional gas chromatography of hydrocarbons up to nC60 for analysis of vacuum gas oils.

    Science.gov (United States)

    Dutriez, Thomas; Courtiade, Marion; Thiébaut, Didier; Dulot, Hugues; Bertoncini, Fabrice; Vial, Jérôme; Hennion, Marie-Claire

    2009-04-03

    In a tense energetic context, the characterization of heavy petroleum fractions becomes essential. Conventional comprehensive two-dimensional gas chromatography (2D-GC or GCxGC) is widely used for middle distillates analysis, but only a few applications are devoted to these heavier fractions. In this paper, it is shown how the optimization of GCxGC separation allowed the determination of suitable high-temperature (HT) conditions, adjusting column properties and operating conditions. 2D separations were evaluated using 2D separation criteria and a new concept of 2D asymmetry (As(2D)). New HT conditions allowed the extension of GCxGC range of applications to heavier hydrocarbons, up to nC(60). A first application of high-temperature two-dimensional gas chromatography (HT-2D-GC) to a full vacuum gas oil (VGO) feed stock is described. Comparisons with other standardized methods illustrate the high potential of HT-2D-GC for heavy fractions analysis.

  9. Modified growth of Ge quantum dots using C{sub 2}H{sub 4} mediation by ultra-high vacuum chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.W. [Institute of Materials Science and Engineering, National Central University, Jhong-Li 32001, Taiwan (China)], E-mail: swlee@ncu.edu.tw; Chen, P.S. [Department of Materials Science and Engineering, Minghsin University of Science and Technology, Hsinchu 30401, Taiwan (China); Cheng, S.L. [Institute of Materials Science and Engineering, National Central University, Jhong-Li 32001, Taiwan (China); Department of Chemical and Materials Engineering, National Central University, Jhong-Li 32001, Taiwan (China); Lee, M.H. [Institute of Electro-optical Science and Technology, National Taiwan Normal University, Taipei 11677, Taiwan (China); Chang, H.T. [Institute of Materials Science and Engineering, National Central University, Jhong-Li 32001, Taiwan (China); Lee, C.-H.; Liu, C.W. [Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2008-07-30

    C{sub 2}H{sub 4} mediations were used to modify the Stranski-Krastanow growth mode of Ge dots on Si(0 0 1) at 550 deg. C by ultra-high vacuum chemical vapor deposition. With appropriate C{sub 2}H{sub 4}-mediation to modify the Si surface, the elongated Ge hut clusters can be transformed to highly uniform Ge domes with a high Ge composition at the core. These C{sub 2}H{sub 4}-mediated Ge dots, almost bounded by {l_brace}1 1 3{r_brace} facets, have an average diameter and height of 55 and 9 nm, respectively. We propose two major mechanisms to depict the formation of these C{sub 2}H{sub 4}-mediated Ge dots: (i) an almost hydrogen-passivated Si surface to limit the nucleation sites for dot formation, and (ii) the incorporation of Ge atoms, repelled by the C-rich areas, into the existing Ge dots. This work provides a useful scheme to tune the topography of Ge dots in an UHV/CVD condition for possible optoelectronic applications.

  10. Vacuum insulation - Panel properties and building applications. HiPTI - High Performance Thermal Insulation - IEA/ECBCS Annex 39 - Final report

    Energy Technology Data Exchange (ETDEWEB)

    Erb, M. (ed.)

    2005-12-15

    This paper takes a look at the properties of vacuum insulation panels (VIP) that have already been developed some time ago for use in appliances such as refrigerators and deep-freezers. Their insulation performance is a factor of five to ten times better than that of conventional insulation. The paper discusses the use of such panels in buildings to provide thin, highly-insulating constructions for walls, roofs and floors. The motivation for examining the applicability of high performance thermal insulation in buildings is discussed, including solutions where severe space limitations and other technical and aesthetic considerations exist. The use of nano-structured materials and laminated foils is examined and discussed. The questions arising from the use of such panels in buildings is discussed and the open questions and risks involved are examined. Finally, an outlook on the introduction of VIP technology is presented and quality assurance aspects are examined. This work was done within the framework of the Task 39 'High Performance Thermal Insulation' of the 'Energy Conservation in Buildings and Community Systems ECBCS' programme of the International Energy Agency IEA.

  11. Mask-free, vacuum-free fabrication of high-conductivity metallic nanowire by spatially shaped ultrafast laser (Conference Presentation)

    Science.gov (United States)

    Wang, Andong; Li, Xiaowei; Qu, Lianti; Lu, Yongfeng; Jiang, Lan

    2017-03-01

    Metal nanowire fabrication has drawn tremendous attention in recent years due to its wide application in electronics, optoelectronics, and plasmonics. However, conventional laser fabrication technologies are limited by diffraction limit thus the fabrication resolution cannot meet the increasingly high demand of modern devices. Herein we report on a novel method for high-resolution high-quality metal nanowire fabrication by using Hermite-Gaussian beam to ablate metal thin film. The nanowire is formed due to the intensity valley in the center of the laser beam while the surrounding film is ablated. Arbitrary nanowire can be generated on the substrate by dynamically adjusting the orientation of the intensity valley. This method shows obvious advantages compared to conventional methods. First, the minimum nanowire has a width of 60 nm (≍1/13 of the laser wavelength), which is much smaller than the diffraction limit. The high resolution is achieved by combining the ultrashort nature of the femtosecond laser and the low thermal conductivity of the thin film. In addition, the fabricated nanowires have good inside qualities. No inner nanopores and particle intervals are generated inside the nanowire, thus endowing the nanowire with good electronic characteristics: the conductivity of the nanowires is as high as 1.2×107 S/m (≍1/4 of buck material), and the maximum current density is up to 1.66×108 A/m2. Last, the nanowire has a good adhesion to the substrates, which can withstand ultrasonic bath for a long time. These advantages make our method a good approach for high-resolution high-quality nanowire fabrication as a complementary method to conventional lithography methods.

  12. Thermophoretic vacuum wand

    Science.gov (United States)

    Klebanoff, Leonard Elliott; Rader, Daniel John

    2000-01-01

    A thermophoretic vacuum wand that is particularly suited for transporting articles in a cleanroom environment so that potential particle contaminants in the air do not become adhered to the surface of the article is described. The wand includes a housing having a platen with a front surface with suction port(s) through the platen; a vacuum source for applying a negative pressure to the suction port(s); and heating device for the object. Heating the article when it is held by the vacuum wand affords thermophoretic protection that effectively prevents particles in the air from depositing onto the article.

  13. Evading death by vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Barroso, A. [Universidade de Lisboa, Centro de Fisica Teorica e Computacional, Faculdade de Ciencias, Lisboa (Portugal); Ferreira, P.M.; Santos, Rui [Universidade de Lisboa, Centro de Fisica Teorica e Computacional, Faculdade de Ciencias, Lisboa (Portugal); Instituto Superior de Engenharia de Lisboa, Lisboa (Portugal); Ivanov, I.P. [Universite de Liege, IFPA, Liege (Belgium); Sobolev Institute of Mathematics, Novosibirsk (Russian Federation); Silva, Joao P. [Instituto Superior de Engenharia de Lisboa, Lisboa (Portugal); Universidade Tecnica de Lisboa, Centro de Fisica Teorica de Particulas (CFTP), Instituto Superior Tecnico, Lisboa (Portugal)

    2013-09-15

    In the Standard Model, the Higgs potential allows only one minimum at tree level. But the open possibility that there might be two scalar doublets enriches the vacuum structure, allowing for the risk that we might now be in a metastable state, which we dub the panic vacuum. Current experiments at the LHC are probing the Higgs particle predicted as a result of the spontaneous symmetry breaking. Remarkably, in the two Higgs model with a softly broken U(1) symmetry, the LHC experiments already allow to exclude many panic vacuum solutions. (orig.)

  14. Cryogenic tritium-hydrogen-deuterium and deuterium-tritium layer implosions with high density carbon ablators in near-vacuum hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Meezan, N. B., E-mail: meezan1@llnl.gov; Hopkins, L. F. Berzak; Pape, S. Le; Divol, L.; MacKinnon, A. J.; Döppner, T.; Ho, D. D.; Jones, O. S.; Khan, S. F.; Ma, T.; Milovich, J. L.; Pak, A. E.; Ross, J. S.; Thomas, C. A.; Benedetti, L. R.; Bradley, D. K.; Celliers, P. M.; Clark, D. S.; Field, J. E.; Haan, S. W. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808 (United States); and others

    2015-06-15

    High Density Carbon (or diamond) is a promising ablator material for use in near-vacuum hohlraums, as its high density allows for ignition designs with laser pulse durations of <10 ns. A series of Inertial Confinement Fusion (ICF) experiments in 2013 on the National Ignition Facility [Moses et al., Phys. Plasmas 16, 041006 (2009)] culminated in a deuterium-tritium (DT) layered implosion driven by a 6.8 ns, 2-shock laser pulse. This paper describes these experiments and comparisons with ICF design code simulations. Backlit radiography of a tritium-hydrogen-deuterium (THD) layered capsule demonstrated an ablator implosion velocity of 385 km/s with a slightly oblate hot spot shape. Other diagnostics suggested an asymmetric compressed fuel layer. A streak camera-based hot spot self-emission diagnostic (SPIDER) showed a double-peaked history of the capsule self-emission. Simulations suggest that this is a signature of low quality hot spot formation. Changes to the laser pulse and pointing for a subsequent DT implosion resulted in a higher temperature, prolate hot spot and a thermonuclear yield of 1.8 × 10{sup 15} neutrons, 40% of the 1D simulated yield.

  15. Conformational studies of self-organized regioregular poly(3-dodecylthiophene)s using non-contact atomic force microscopy in ultra high vacuum condition

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Shukichi [Kansai Advanced Research Center, National Institute of Information and Communications Technology (KARC-NiCT), 588-2, Iwaoka, Nishi-ku, Kobe 651-2492 (Japan)]. E-mail: tanakas@nict.go.jp; Grevin, Benjamin [Laboratoire de Physique des Metaux Synthetiques UMR5819-SprAM, DRFMC CEA-Grenoble, 17 rue des Martyrs 38054 Grenoble Cedex 9 (France); Rannou, Patrice [Laboratoire de Physique des Metaux Synthetiques UMR5819-SprAM, DRFMC CEA-Grenoble, 17 rue des Martyrs 38054 Grenoble Cedex 9 (France); Suzuki, Hitoshi [Kansai Advanced Research Center, National Institute of Information and Communications Technology (KARC-NiCT), 588-2, Iwaoka, Nishi-ku, Kobe 651-2492 (Japan); Mashiko, Shinro [Kansai Advanced Research Center, National Institute of Information and Communications Technology (KARC-NiCT), 588-2, Iwaoka, Nishi-ku, Kobe 651-2492 (Japan)

    2006-03-21

    Conformations of one of the variations of {pi}-conjugated poly-alkylthiophene, poly(3-dodecylthiophene)s (P3DDT)s on the surface in ultra high vacuum (UHV) were investigated by non-contact atomic force microscopy (NC-AFM) operated by frequency-modulation mode (FM-mode). From individual molecules to several multi-layered ones, polymer chains on the surface were clearly resolved on conducting highly oriented pyrolytic graphite (HOPG) substrates and insulating mica ones, respectively. Solvent evaporation was found to have two stages, which influenced the diffusion, ordering, and adhesion processes of polymer chains on the substrate. To keep the ordered conformations of deposited polymer chains when they are transferred from ambient condition to UHV, these evaporation processes should be carefully considered. The initial conformation of polymers on the substrate was found to depend strongly on the lattice matching conditions and interactions between polymers and substrates. Formations of stripe-like structures of P3DDT polymers were found on the mica substrates, which is promising for device application.

  16. Space simulation chambers for complete satellites: High vacuum and extreme temperatures challenges; Camaras de simulacion espacial para satelites completos: los retos de alto vacio y temperaturas extremas

    Energy Technology Data Exchange (ETDEWEB)

    Galan, M.; Cazador, M.

    2010-07-01

    During any satellite development phase, many operational factors can only be experimentally determined by testing under the most extreme environmental conditions that will be encountered in its life. Simulating the different temperatures, thermal loads and vacuum conditions allows analyzing the suitability of new materials, components and systems for these extreme conditions. In a space project, thermal vacuum testing reaches 70% of the total testing costs. They are the most similar conditions to the real ones that will be encountered in the outer space.In this article, the function of both the thermal and vacuum subsystems are explained and analyzed.Thermal control units are the most fundamental part in a space simulation chamber; they must cover the required extreme temperature range with the required heating and cooling speed. The vacuum subsystem must allow reaching the required operating pressure within the specified time, handling significant degassing loads both from the satellite and the large exposed surfaces inside the chamber. (Author) 6 refs.

  17. Vacuum mechatronics first international workshop

    Energy Technology Data Exchange (ETDEWEB)

    Belinski, S.E.; Shirazi, M.; Hackwood, S.; Beni, G. (eds.) (California Univ., Santa Barbara, CA (USA))

    1989-01-01

    This report contains papers on the following topics: proposed epitaxial thin film growth in the ultra-vacuum of space; particle monitoring and control in vacuum processing equipment; electrostatic dust collector for use in vacuum systems; materials evaluation of an electrically noisy vacuum slip ring assembly; an overview of lubrication and associated materials for vacuum service; the usage of lubricants in a vacuum environment; guidelines and practical applications for lubrication in vacuum; recent development in leak detector and calibrator designs; the durability of ballscrews for ultrahigh vacuum; vacuum-compatible robot for self-contained manufacturing systems; the design, fabrication, and assembly of an advanced vacuum robotics system for space payload calibration; design criteria for mechanisms used in space; and concepts and requirements for semiconductor multiprocess integration in vacuum. These papers are indexed separately elsewhere.

  18. Improved Vacuum-Tight Connector

    Science.gov (United States)

    Rudin, Frank

    1989-01-01

    Simple reinforcing tube increases service life and improves seal. Short stainless-steel tube inserted in copper tube to reinforce against compression, preventing leaks due to thermal distortion or to collapse under squeeze of ferrule in compressure fitting. Several test specimens of improved connector constructed, tested, and evaluated. Fittings not only operated successfully at required operating conditions of vacuum and temperature but also consistently demonstrated high reliability after loosened and tightened many times.

  19. NCSX Vacuum Vessel Fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Viola, M. E.; Brown, T.; Heitzenroeder, P.; Malinowski, F.; Reiersen, W.; Sutton, L.; Goranson, P.; Nelson, B.; Cole, M.; Manuel, M.; McCorkle, D.

    2005-10-07

    The National Compact Stellarator Experiment (NCSX) is being constructed at the Princeton Plasma Physics Laboratory (PPPL) in conjunction with the Oak Ridge National Laboratory (ORNL). The goal of this experiment is to develop a device which has the steady state properties of a traditional stellarator along with the high performance characteristics of a tokamak. A key element of this device is its highly shaped Inconel 625 vacuum vessel. This paper describes the manufacturing of the vessel. The vessel is being fabricated by Major Tool and Machine, Inc. (MTM) in three identical 120º vessel segments, corresponding to the three NCSX field periods, in order to accommodate assembly of the device. The port extensions are welded on, leak checked, cut off within 1" of the vessel surface at MTM and then reattached at PPPL, to accommodate assembly of the close-fitting modular coils that surround the vessel. The 120º vessel segments are formed by welding two 60º segments together. Each 60º segment is fabricated by welding ten press-formed panels together over a collapsible welding fixture which is needed to precisely position the panels. The vessel is joined at assembly by welding via custom machined 8" (20.3 cm) wide spacer "spool pieces." The vessel must have a total leak rate less than 5 X 10-6 t-l/s, magnetic permeability less than 1.02μ, and its contours must be within 0.188" (4.76 mm). It is scheduled for completion in January 2006.

  20. Vacuum plasma spray coating

    Science.gov (United States)

    Holmes, Richard R.; Mckechnie, Timothy N.

    1989-01-01

    Currently, protective plasma spray coatings are applied to space shuttle main engine turbine blades of high-performance nickel alloys by an air plasma spray process. Originally, a ceramic coating of yttria-stabilized zirconia (ZrO2.12Y2O3) was applied for thermal protection, but was removed because of severe spalling. In vacuum plasma spray coating, plasma coatings of nickel-chromium-aluminum-yttrium (NiCrAlY) are applied in a reduced atmosphere of argon/helium. These enhanced coatings showed no spalling after 40 MSFC burner rig thermal shock cycles between 927 C (1700 F) and -253 C (-423 F), while current coatings spalled during 5 to 25 test cycles. Subsequently, a process was developed for applying a durable thermal barrier coating of ZrO2.8Y2O3 to the turbine blades of first-stage high-pressure fuel turbopumps utilizing the enhanced NiCrAlY bond-coating process. NiCrAlY bond coating is applied first, with ZrO2.8Y2O3 added sequentially in increasing amounts until a thermal barrier coating is obtained. The enchanced thermal barrier coating has successfully passed 40 burner rig thermal shock cycles.

  1. Development of Subischial Prosthetic Sockets with Vacuum-Assisted Suspension for Highly Active Persons with Transfemoral Amputations

    Science.gov (United States)

    2015-10-01

    comfort during sitting, standing, walking, and running in highly active transfemoral prosthesis users. The Specific Aims of this project are to: A1...with 3 lost to follow up (Table 1). Of the remaining 7 subjects, 6 have completed baseline biomechanics testing in their standard of care socket; 6/7...have completed baseline fluoroscopy testing in their standard of care socket; 3/7 have completed biomechanics testing in the sub-ischial socket (data

  2. Cold Vacuum Drying Facility

    Data.gov (United States)

    Federal Laboratory Consortium — Located near the K-Basins (see K-Basins link) in Hanford's 100 Area is a facility called the Cold Vacuum Drying Facility (CVDF).Between 2000 and 2004, workers at the...

  3. Cosmology of gravitational vacuum

    CERN Document Server

    Burdyuzha, V; Pacheco, J

    2008-01-01

    Production of gravitational vacuum defects and their contribution to the energy density of our Universe are discussed. These topological microstructures (defects) could be produced in the result of creation of the Universe from "nothing" when a gravitational vacuum condensate has appeared. They must be isotropically distributed over the isotropic expanding Universe. After Universe inflation these microdefects are smoothed, stretched and broken up. A part of them could survive and now they are perceived as the structures of Lambda-term and an unclustered dark matter. It is shown that the parametrization noninvariance of the Wheeler-De Witt equation can be used to describe phenomenologically vacuum topological defects of different dimensions (worm-holes, micromembranes, microstrings and monopoles). The mathematical illustration of these processes may be the spontaneous breaking of the local Lorentz-invariance of the quasi-classical equations of gravity. Probably the gravitational vacuum condensate has fixed tim...

  4. Handbook of vacuum technology

    CERN Document Server

    2016-01-01

    This comprehensive, standard work has been updated to remain an important resource for all those needing detailed knowledge of the theory and applications of vacuum technology. With many numerical examples and illustrations to visualize the theoretical issues.

  5. Vacuum Camera Cooler

    Science.gov (United States)

    Laugen, Geoffrey A.

    2011-01-01

    Acquiring cheap, moving video was impossible in a vacuum environment, due to camera overheating. This overheating is brought on by the lack of cooling media in vacuum. A water-jacketed camera cooler enclosure machined and assembled from copper plate and tube has been developed. The camera cooler (see figure) is cup-shaped and cooled by circulating water or nitrogen gas through copper tubing. The camera, a store-bought "spy type," is not designed to work in a vacuum. With some modifications the unit can be thermally connected when mounted in the cup portion of the camera cooler. The thermal conductivity is provided by copper tape between parts of the camera and the cooled enclosure. During initial testing of the demonstration unit, the camera cooler kept the CPU (central processing unit) of this video camera at operating temperature. This development allowed video recording of an in-progress test, within a vacuum environment.

  6. ISR Intersection Vacuum Chamber

    CERN Multimedia

    1975-01-01

    This special vacuum chamber presenting a lateral opening at the beam crossing point is one of the many chambers specifically designed for a particular experiment. Here it is shown during assembly at the ISR mechanical worshop.

  7. On Puthoff's Semiclassical Electron and Vacuum Energy

    Science.gov (United States)

    Pereira, N. R.

    2016-09-01

    A possible connection between a point electron and vacuum energy was recently claimed by Puthoff (Int. J. Theor. Phys. 46, 3005 (2007)). He envisions a point electron as an ideally conducting spherical shell with a distributed charge on the surface, in equilibrium with the radiation pressure from electromagnetic vacuum fluctuations on the outside, and claims that his analysis demonstrates the reality of high-energy-density vacuum fluctuation fields. The present paper finds, instead, that the analysis is meaningless without specific knowledge on the cutoff frequency that is a free parameter in the model.

  8. A Planck Vacuum Cosmology

    Directory of Open Access Journals (Sweden)

    Daywitt W. C.

    2009-04-01

    Full Text Available Both the big-bang and the quasi-steady-state cosmologies originate in some type of Planck state. This paper presents a new cosmological theory based on the Planck- vacuum negative-energy state, a state consisting of a degenerate collection of negative- energy Planck particles. A heuristic look at the Einstein field equation provides a con- vincing argument that such a vacuum state could provide a theoretical explanation for the visible universe.

  9. Power vacuum tubes handbook

    CERN Document Server

    Whitaker, Jerry

    2012-01-01

    Providing examples of applications, Power Vacuum Tubes Handbook, Third Edition examines the underlying technology of each type of power vacuum tube device in common use today. The author presents basic principles, reports on new development efforts, and discusses implementation and maintenance considerations. Supporting mathematical equations and extensive technical illustrations and schematic diagrams help readers understand the material. Translate Principles into Specific Applications This one-stop reference is a hands-on guide for engineering personnel involved in the design, specification,

  10. Wireless Integrated Microelectronic Vacuum Sensor System

    Science.gov (United States)

    Krug, Eric; Philpot, Brian; Trott, Aaron; Lawrence, Shaun

    2013-01-01

    NASA Stennis Space Center's (SSC's) large rocket engine test facility requires the use of liquid propellants, including the use of cryogenic fluids like liquid hydrogen as fuel, and liquid oxygen as an oxidizer (gases which have been liquefied at very low temperatures). These fluids require special handling, storage, and transfer technology. The biggest problem associated with transferring cryogenic liquids is product loss due to heat transfer. Vacuum jacketed piping is specifically designed to maintain high thermal efficiency so that cryogenic liquids can be transferred with minimal heat transfer. A vacuum jacketed pipe is essentially two pipes in one. There is an inner carrier pipe, in which the cryogenic liquid is actually transferred, and an outer jacket pipe that supports and seals the vacuum insulation, forming the "vacuum jacket." The integrity of the vacuum jacketed transmission lines that transfer the cryogenic fluid from delivery barges to the test stand must be maintained prior to and during engine testing. To monitor the vacuum in these vacuum jacketed transmission lines, vacuum gauge readings are used. At SSC, vacuum gauge measurements are done on a manual rotation basis with two technicians, each using a handheld instrument. Manual collection of vacuum data is labor intensive and uses valuable personnel time. Additionally, there are times when personnel cannot collect the data in a timely fashion (i.e., when a leak is detected, measurements must be taken more often). Additionally, distribution of this data to all interested parties can be cumbersome. To simplify the vacuum-gauge data collection process, automate the data collection, and decrease the labor costs associated with acquiring these measurements, an automated system that monitors the existing gauges was developed by Invocon, Inc. For this project, Invocon developed a Wireless Integrated Microelectronic Vacuum Sensor System (WIMVSS) that provides the ability to gather vacuum

  11. COMPARISON OF VACUUM AND HIGH PRESSURE EVAPORATED WOOD HYDROLYZATE FOR ETHANOL PRODUCTION BY REPEATED FED-BATCH USING FLOCCULATING SACCHAROMYCES CEREVISIAE

    Directory of Open Access Journals (Sweden)

    Anahita Dehkhoda

    2009-02-01

    Full Text Available With the aim of increasing the sugars concentration in dilute-acid ligno-cellulosic hydrolyzate to more than 100 g/l for industrial applications, the hydrolyzate from spruce was concentrated about threefold by high-pressure or vacuum evaporations. It was then fermented by repeated fed-batch cultivation using flocculating Saccharomyces cerevisiae with no prior detoxification. The sugars and inhibitors concentrations in the hydrolyzates were compared after the evaporations and also fermenta-tion. The evaporations were carried out either under vacuum (VEH at 0.5 bar and 80°C or with 1.3 bar pressure (HPEH at 107.5°C, which resulted in 153.3 and 164.6 g/l total sugars, respectively. No sugar decomposition occurred during either of the evaporations, while more than 96% of furfural and to a lesser extent formic and acetic acids disappeared from the hydrolyzates. However, HMF and levulinic acid remained in the hydrolyzates and were concentrated proportionally. The concentrated hydrolyzates were then fermented in a 4 l bioreactor with 12-22 g/l yeast and 0.14-0.22 h-1 initial dilute rates (ID. More than 84% of the fermentable sugars present in the VEH were fermented by fed-batch cultivation using 12 g/l yeast and initial dilution rate (ID of 0.22 h-1, and resulted in 0.40±0.01 g/g ethanol from the fermentable sugars in one cycle of fermentation. Fermentation of HPEH was as successful as VEH and resulted in more than 86% of the sugar consumption under the corresponding conditions. By lowering the initial dilution rate to 0.14 h-1, more than 97% of the total fermentable sugars were consumed, and ethanol yield was 0.44±0.01 g/g in one cycle of fermentation. The yeast was able to convert or assimilate HMF, levulinic, acetic, and formic acids by 96, 30, 43, and 74%, respectively.

  12. High-Resolution Infrared-Vacuum Ultraviolet Photoion and Pulsed Field Ionization-Photoelectron Methods for Spectroscopic Studies of Neutrals and Cations

    Institute of Scientific and Technical Information of China (English)

    Xi Xing; Beth Reed; Mi Kyung Bahng; Peng Wang; Hin Koo Woo; Sun Jong Baek; Chee Shine Lam; Cheuk Yiu Ng

    2008-01-01

    We show that by scanning the frequency of a single mode infrared (IR) optical parametric oscillator (IR- OPO) laser to excite the molecular species of interest and fixing the frequency of a vacuum ultraviolet (VUV) laser to photoionize the IR excited species, high-resolution IR spectra of polyatomic neutrals can be obtained with high sensitivity. The fact that this IR-VUV-photoion (IR-VUV-PI) method is based on VUV photoionization probe, and thus, allows the identification of the neutral IR absorber, makes it applicable for IR spectroscopy measurements of isotopemers, radicals, and clusters, which usually exist as impure samples. The highly resolved IR-VUV-PI measurements achieved using the single mode IR-OPO laser have made possible the selection of single rovibrational states of CH3X (X=Br and I), C2H4, and C3H4 for VUV-pulsed field ionization-photoelectron (VUV-PFI-PE) measurements, resulting in rovibrationally resolved photoelectron spectra for these polyatomic molecules. These experiments show that the signal- to-noise ratios of the IR-VUV-PI and IR-VUV-PFI-PE spectra obtained by employing the high-resolution IR-OPO laser are significantly higher than those observed in previous IR-VUV-PI and IR-VUV-PFI-PE studies using a low-resolution IR-OPO laser. Further improvement in sensitivity of IR-VUV-PI and IR- VUV-PFI-PE measurements by using the collinear arrangement of IR-VUV lasers and molecular beam is discussed.

  13. Absorption spectroscopy of xenon and ethylene-noble gas mixtures at high pressure: towards Bose-Einstein condensation of vacuum ultraviolet photons

    Science.gov (United States)

    Wahl, Christian; Brausemann, Rudolf; Schmitt, Julian; Vewinger, Frank; Christopoulos, Stavros; Weitz, Martin

    2016-12-01

    Bose-Einstein condensation is a phenomenon well known for material particles as cold atomic gases, and this concept has in recent years been extended to photons confined in microscopic optical cavities. Essential for the operation of such a photon condensate is a thermalization mechanism that conserves the average particle number, as in the visible spectral regime can be realized by subsequent absorption re-emission processes in dye molecules. Here we report on the status of an experimental effort aiming at the extension of the concept of Bose-Einstein condensation of photons towards the vacuum ultraviolet spectral regime, with gases at high-pressure conditions serving as a thermalization medium for the photon gas. We have recorded absorption spectra of xenon gas at up to 30 bar gas pressure of the 5p^6-5p^56s transition with a wavelength close to 147 nm. Moreover, spectra of ethylene noble gas mixtures between 158 and 180 nm wavelength are reported.

  14. Changes in the microbiota of lamb packaged in a vacuum and in modified atmospheres during chilled storage analysed by high-throughput sequencing.

    Science.gov (United States)

    Wang, Taojun; Zhao, Liang; Sun, Yanan; Ren, Fazheng; Chen, Shanbin; Zhang, Hao; Guo, Huiyuan

    2016-11-01

    Changes in the microbiota of lamb were investigated under vacuum packaging (VP) and under 20% CO2/80% N2 (LC), 60% CO2/40% N2 (MC), and 100% CO2 (HC) modified atmosphere packaging (MAP) during chilled storage. Viable counts were monitored, and the total microbial communities were assessed by high-throughput sequencing. The starting community had the highest microbial diversity, after which Lactococcus and Carnobacterium spp. outcompeted during the 28-day storage. The relative abundances of Brochothrix spp. in the LC atmosphere were much higher than those of the other groups on days 7 and 28. The bacterial inhibiting effect of the MAP environments on microbial growth was positively correlated with the CO2 concentration. The HC atmosphere inhibited microbial growth and delayed changes in the microbial community composition, extending the lamb's shelf life by approximately 7days compared with the VP atmosphere. Lamb packaged in the VP atmosphere had a more desirable colour but a higher weight loss than lamb packaged in the MAP atmospheres.

  15. Generation of a quasi-monoenergetic high energy proton beam from a vacuum-sandwiched double layer target irradiated by an ultraintense laser pulse

    Energy Technology Data Exchange (ETDEWEB)

    Nam Kim, Kyung; Lee, Kitae, E-mail: klee@kaeri.re.kr; Hee Park, Seong; Young Lee, Ji; Uk Jeong, Young; Vinokurov, Nikolay [Center for Quantum-Beam-based Radiation Research, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Gi Kim, Yong [Department of Physics, Kongju National University, Kongju (Korea, Republic of)

    2014-04-15

    An acceleration mechanism to generate a high energy proton beam with a narrow energy spread in the laser-induced plasma acceleration of a proton beam is proposed; this mechanism employs two thin foils separated by a narrow vacuum gap. Instead of a thin sheath field at the plasma surfaces, it utilizes an electrostatic field formed in the bulk of the plasma. From a one-dimensional fluid analysis, it has been found that with an appropriate target thickness, protons on the front surface of the second layer can be fed into the plasma, in which the protons are accelerated by an electrostatic field built into the bulk of the plasma. This leads to a proton beam with higher energy and a narrower energy spread than those accelerated at the rear surface of the second layer. The acceleration mechanism is also verified by a two-dimensional particle-in-cell simulation. With a 27-fs long and 2×10{sup 19} W/cm{sup 2} intense laser pulse, a proton beam with an 18-MeV peak energy and a 35% energy spread is generated. The peak energy is higher than that from the rear surface of the second layer by a factor of 3.

  16. An Examination of the Surface and Sub-Surface of Modern and Historical Platinum Photographic Prints Using Low Vacuum High-Resolution Scanning Electron Microscopy.

    Science.gov (United States)

    Ravines, Patrick; Erdman, Natasha; McElroy, Rob

    2016-08-01

    Photographic prints of platinum metal on paper supports are some of the most exquisite and expressive in the world of fine art photography. Platinum prints were produced from about 1890 to 1920 in the USA and Europe. The chemical and material nature of these valuable prints is of great interest to many who are interested in their long-term preservation, in the intersection of science and art, and in the scientific and technical study of cultural heritage. This paper presents the results of a characterization study using newer electron microscopy techniques. In this study, a low vacuum high-resolution scanning electron microscope was used to study the surface and sub-surface of historic and modern platinum and/or palladium print samples. Using environmental SEM pressures allowed us to investigate the actual top surface and sub-surface with cross-sections without any preparation; no coatings of carbon or other material. Cross-sections were prepared using an argon plasma cross-polishing system. This study shows that the photographic image of platinum prints is composed of platinum nanoparticles embedded in the upper layers of the paper's cellulosic fibers.

  17. "Flat-Fish" Vacuum Chamber

    CERN Multimedia

    CERN PhotoLab

    1978-01-01

    The picture shows a "Flat-Fish" vacuum chamber being prepared in the ISR workshop for testing prior to installation in the Split Field Magnet (SFM) at intersection I4. The two shells of each part were hydroformed from 0.15 mm thick inconel 718 sheet (with end parts in inconel 600 for easier manual welding to the arms) and welded toghether with two strips which were attached by means of thin stainless steel sheets to the Split Field Magnet poles in order to take the vertical component of the atmospheric pressure force. This was the thinnest vacuum chamber ever made for the ISR. Inconel material was chosen for its high elastic modulus and strenght at chamber bake-out temperature. In this picture the thin sheets transferring the vertical component of the atmosferic pressure force are attached to a support frame for testing. See also 7712182, 7712179.

  18. Stabilization flyuorytopodibnoyi structure in oxide vacuum condensate

    Directory of Open Access Journals (Sweden)

    О.М. Заславський

    2006-01-01

    Full Text Available  The influence of the oxide-stabilizer content, M'-cation radius and film deposition temperature on the stabilization of the fluorite-like solid solutions in the zirconium and hafnium oxides-based vacuum condensates, obtained by Laser-evaporating method, was investigated. The optimum parameters of the coatication of the isotropic thermostable coverings was determined. This results were explained by using of the high-speed condensation in vacuum theory.

  19. LER Vacuum Studies

    Energy Technology Data Exchange (ETDEWEB)

    Matter, Regina S.

    2000-06-27

    During the Summer of 1999 the vacuum in LER was studied in order to answer a few questions: (1) how fast is the vacuum system cleaning; (2) when will the required operating pressure 10 nTorr be reached; (3) how fast do the TSP's saturate; and (4) what is the present average pressure in LER and what is the corresponding beam lifetime? Once {Delta}P/I, the coefficient relating the pressure to beam current and the base pressure is calculated, it is easy to find the time constants associated with the cleaning of the vacuum system and the saturation of the TSP's. In addition, these calculations showed that vertical steering of the LER orbit affects the vacuum and that leaks cause the TSP's to saturate. It is difficult to calculate the average pressure in the ring because most of the ion pumps in the straight sections do not read pressure accurately. Secondly, how do you calculate the conductance between the chamber and the anti-chamber? Thirdly, the gas load is unevenly distributed along the ring because of photon stops and leaks. However, the average vacuum pressure seen by the beam in the arcs is roughly three times higher than the pressure measured at the ion pumps, according to Artem Kulikov. Instead of calculating the average pressure in the ring, the author has calculated the coefficient relating the inverse beam lifetime to the beam current to see the long term improvement of the LER beam lifetime as the vacuum system is scrubbed. These calculations showed that the lifetime, including the low intensity lifetime, is limited by the vacuum pressure. The results reported here are obtained from numerical calculations.

  20. Technology Study on Producing High Melting Point Microcrystalline Wax From Shenbei/Daqing Vacuum Residue Oil%沈北/大庆减压渣油生产高熔点微晶蜡工艺研究

    Institute of Scientific and Technical Information of China (English)

    金秀英; 陈白莉; 杜晓敏; 王玉玲; 范燕

    2013-01-01

      沈北/大庆减压渣油中含有丰富的微晶蜡。将渣油亚临界丙烷脱沥青得到轻脱油,再经酮苯脱油-白土精制生产高熔点微晶蜡。说明大庆、沈北混合原油减压渣油经脱沥青等系列工艺处理生产光亮油和微晶蜡的技术可行性,提出了大庆、沈北混合原油减压渣油综合利用的途径。%There is abundant microcrystalline wax in Shenbei/Taqing vacuum residue oil. Light deasphalting oil is often obtained from vacuum residue oil by subcritical propane deasphalting process, then microcrystalline wax with high melting point can be produced by butanone-toluene solvent deoiling and clay-treated refining. In this paper,the technical and economic feasibility of producing bright stock and microcrystalline wax from the vacuum residue of Daqing and Shenbei mixed crude by deasphalting etc.processes was discussed according to the pilot plant test results .Utilization ways of vacuum residue of Daqing and Shenbei mixed crude were put forward.

  1. Femtosecond time-resolved photoelectron spectroscopy with a vacuum-ultraviolet photon source based on laser high-order harmonic generation.

    Science.gov (United States)

    Wernet, Philippe; Gaudin, Jérôme; Godehusen, Kai; Schwarzkopf, Olaf; Eberhardt, Wolfgang

    2011-06-01

    A laser-based tabletop approach to femtosecond time-resolved photoelectron spectroscopy with photons in the vacuum-ultraviolet (VUV) energy range is described. The femtosecond VUV pulses are produced by high-order harmonic generation (HHG) of an amplified femtosecond Ti:sapphire laser system. Two generations of the same setup and results from photoelectron spectroscopy in the gas phase are discussed. In both generations, a toroidal grating monochromator was used to select one harmonic in the photon energy range of 20-30 eV. The first generation of the setup was used to perform photoelectron spectroscopy in the gas phase to determine the bandwidth of the source. We find that our HHG source has a bandwidth of 140 ± 40 meV. The second and current generation is optimized for femtosecond pump-probe photoelectron spectroscopy with high flux and a small spot size at the sample of the femtosecond probe pulses. The VUV radiation is focused into the interaction region with a toroidal mirror to a spot smaller than 100 × 100 μm(2) and the flux amounts to 10(10) photons/s at the sample at a repetition rate of 1 kHz. The duration of the monochromatized VUV pulses is determined to be 120 fs resulting in an overall pump-probe time resolution of 135 ± 5 fs. We show how this setup can be used to map the transient valence electronic structure in molecular dissociation. © 2011 American Institute of Physics

  2. FRIB driver linac vacuum model and benchmarks

    CERN Document Server

    Durickovic, Bojan; Kersevan, Roberto; Machicoane, Guillaume

    2014-01-01

    The Facility for Rare Isotope Beams (FRIB) is a superconducting heavy-ion linear accelerator that is to produce rare isotopes far from stability for low energy nuclear science. In order to achieve this, its driver linac needs to achieve a very high beam current (up to 400 kW beam power), and this requirement makes vacuum levels of critical importance. Vacuum calculations have been carried out to verify that the vacuum system design meets the requirements. The modeling procedure was benchmarked by comparing models of an existing facility against measurements. In this paper, we present an overview of the methods used for FRIB vacuum calculations and simulation results for some interesting sections of the accelerator. (C) 2013 Elsevier Ltd. All rights reserved.

  3. Fate of Electroweak Vacuum during Preheating

    CERN Document Server

    Ema, Yohei; Nakayama, Kazunori

    2016-01-01

    Our electroweak vacuum may be metastable in light of the current experimental data of the Higgs/top quark mass. If this is really the case, high-scale inflation models require a stabilization mechanism of our vacuum during inflation. A possible candidate is the Higgs-inflaton/-curvature coupling because it induces an additional mass term to the Higgs during the slow roll regime. However, after the inflation, the additional mass term oscillates, and it can potentially destabilize our electroweak vacuum via production of large Higgs fluctuations during the inflaton oscillation era. In this paper, we study whether or not the Higgs-inflaton/-curvature coupling can save our vacuum by properly taking account of Higgs production during the preheating stage. We put upper bounds on the Higgs-inflaton/-curvature coupling, and discuss possible dynamics that might relax them.

  4. Re-circulating linac vacuum system

    Energy Technology Data Exchange (ETDEWEB)

    Wells, Russell P.; Corlett, John N.; Zholents, Alexander A.

    2003-05-09

    The vacuum system for a proposed 2.5 GeV, 10{Mu}A recirculating linac synchrotron light source [1] is readily achievable with conventional vacuum hardware and established fabrication processes. Some of the difficult technical challenges associated with synchrotron light source storage rings are sidestepped by the relatively low beam current and short beam lifetime requirements of a re-circulating linac. This minimal lifetime requirement leads directly to relatively high limits on the background gas pressure through much of the facility. The 10{Mu}A average beam current produces very little synchrotron radiation induced gas desorption and thus the need for an ante-chamber in the vacuum chamber is eliminated. In the arc bend magnets, and the insertion devices, the vacuum chamber dimensions can be selected to balance the coherent synchrotron radiation and resistive wall wakefield effects, while maintaining the modest limits on the gas pressure and minimal outgassing.

  5. Experiment on heat transfer and temperature distribution of insulation jacket in a high-vacuum-multilayer-insulation cryogenic tank after sudden, catastrophic loss of insulation vacuum%高真空多层绝热低温容器完全真空丧失后传热及绝热夹层内温度分布规律实验

    Institute of Scientific and Technical Information of China (English)

    谢高峰; 朱鸣; 汪荣顺

    2011-01-01

    在搭建了高真空多层绝热低温容器完全真空丧失传热研究实验台的基础上,分别利用干燥氮气、二氧化碳、氧气、氦气及空气为破空介质,进行了高真空多层绝热低温容器发生完全真空丧失事故后的传热实验研究.实验中通过流量计和温度采集系统测得了高真空多层绝热低温容器在发生完全真空丧失事故后的排放率和绝热夹层内的温度分布规律.实验结果表明,导入高真空多层绝热低温容器绝热夹层的气体种类对其完全真空丧失后的传热过程有很大的影响.%A test rig for high-vacuum-multilayer-insulation( HVMLI) cryogenic tank was built up and experiments were conducted on a sudden, catastrophic loss of insulation vacuum ( SCLIV) cryogenic tank by using gases of nitrogen, carbon dioxide, oxygen, helium and air as leaking medium respectively. The venting rates and temperature in the insulation jacket were measured after five kinds of gas leaking into it. The results show that the type of gas leaking into the vacuum interlayer has great influence on the process of heat transfer after when the loss of vacuum happens.

  6. 真空蒸汽在热敏性药物浓缩的应用探讨%Discussion on Application of Vacuum Steam in Concentrating Thermosensitive Drug

    Institute of Scientific and Technical Information of China (English)

    王国君; 徐世富

    2013-01-01

    选择温度低于100℃的真空蒸汽作为热源,通过间壁列管式降膜蒸发器对热敏性药物中的乙酸乙酯蒸发、冷凝、回收,从而提高热敏性药物的纯度。提高蒸发效率,降低设备占地面积。以工业应用为例对设备选型及加热介质选择进行阐述。%Using vacuum steam whose temperature was below 100 ℃ as heat source, the thermosensitive drug was purified via evaporation, condensation and recovery of ethyl acetate in the thermosensitive drug with the tubular falling film evaporator. The results show that the evaporation efficiency is improved;the occupied area of the equipment is reduced. At last, selection of equipment types and heating media were discussed.

  7. High temperature autoclave vacuum seals

    Science.gov (United States)

    Hoffman, J. R.; Simpson, W. G.; Walker, H. M.

    1971-01-01

    Aluminum sheet forms effective sealing film at temperatures up to 728 K. Soft aluminum wire rings provide positive seal between foil and platen. For applications at temperatures above aluminum's service temperature, stainless steel is used as film material and copper wire as sealant.

  8. Acetylene Vacuum Carburizing

    Institute of Scientific and Technical Information of China (English)

    Hitoshi Iwata

    2004-01-01

    Almost 30 years has passed since the publication of materials on vacuum carburizing technology, and is attracting a great deal of attention as a technology capable of being used as a substitute for gas carburizing technology.However, the technology was not popular except in specific fields. The main reason for this is due to a variety of harmful influences accompanying the sooting problems caused by CH4 or C3H8. We have succeeded in that the occurrence of sooting was suppressed by utilizing acetylene, at extremely low pressure for carburizing (below 1 kPa). This process is now showing the excellent quality and prospects for this technology in terms of quality, economy and safety. At present almost 70 practical mass production furnaces are used in production lines, in Japan and abroad. At this time, we will report summary of the present acetylene vacuum carbufizing process and the actual results obtained by these acetylene vacuum carbufizing furnaces for mass production.

  9. Handbook of vacuum physics

    CERN Document Server

    1964-01-01

    Handbook of Vacuum Physics, Volume 3: Technology is a handbook of vacuum physics, with emphasis on the properties of miscellaneous materials such as mica, oils, greases, waxes, and rubber. Accurate modern tables of physical constants, properties of materials, laboratory techniques, and properties of commercial pumps, gauges, and leak detectors are presented. This volume is comprised of 12 chapters and begins with a discussion on pump oils, divided into rotary pump oils and vapor pump oils. The next chapter deals with the properties and applications of greases, including outgassing and vapor pr

  10. A rotating quantum vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Lorenci, V.A. de; Svaiter, N.F. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)

    1996-11-01

    It was investigated which mapping has to be used to compare measurements made in a rotating frame to those made in an inertial frame. Using a non-Galilean coordinate transformation, the creation-annihilation operators of a massive scalar field in the rotating frame are not the same as those of an inertial observer. This leads to a new vacuum state(a rotating vacuum) which is a superposition of positive and negative frequency Minkowski particles. Polarization effects in circular accelerators in the proper frame of the electron making a connection with the inertial frame point of view were analysed. 65 refs.

  11. Ahşap Kurutmada Çevre Dostu bir Teknoloji : Yüksek Frekans / High-Frequency-Vacuum Wood Drying Technology

    Directory of Open Access Journals (Sweden)

    Cengiz Güler

    2012-12-01

    Full Text Available Katma değerli olmasına karşın kurutulması güç ağaç türlerine ait kalın kerestelerin, klasik kurutma metoduyla çok uzun sürelerde kurutulabilmesi ve istenen kalite düzeylerinin tam olarak elde edilememesi nedeniyle günümüzde Yüksek Frekans-Vakum kombinasyonlu kurutma metodu (YFV kendini göstermiş durumdadır. Geçmişte özellikle yatırım maliyetleri ve teknolojik altyapı zorlukları nedeniyle yaygınlaşamayan bu yöntem tekrar güncel hale gelmiştir. Bu kurutma metodunda prensip; ısı kaynağının, elektrik enerjisi olmasıdır. Dolayısı ile katı ve sıvı yakıta göre çevre dostu olduğu kabul edilebilir. Bu metot ile ağaç malzemeye gönderilen elektromanyetik dalgaların meydana getirdiği ısıdan yararlanmak suretiyle, kalın ve güç kuruyan, başlangıç nemi yüksek olan ağaç türlerinin %10 un altındaki sonuç nemlerine kadar çok kısa sürelerde kurutulması amaçlanmaktadır. Bu çalışmada öncelikle kurutma teknoloji hakkında genel bilgi verilmiştir. Daha sonra ise, günümüze kadar yapılan orijinal çalışmalar özetlenerek klasik yöntemle kurutulmasında önemli zorluklar olan, kurutma süresi çok uzun olan veya hiç kurutulamayan Meşe, Ceviz, Kayın, İroko, Kestane gibi ağaç türlerinin kalın kerestelerinin kurutulması denemelerinden elde edilen sonuçlar ortaya konulmuştur. Son bölümde ise elde edilen bu sonuçlar özellikle metodun donanım ve işletme giderleri, ortaya çıkan kurutma süreleri ve kalite düzeyleri, çevreye uyumlu teknoloji ekseninde ele alınmıştır. Ayrıca, bu metodun kereste kurutma dışında diğer tarımsal ürün ve atıkların kurutulmasında kullanılabilir olması nedeniyle çevreye uyumlu üretim ve geri dönüşüme sağladığı katkı da bu kapsamda irdelenmiştir. High-Frequency-Vacuum Wood Drying Technology High density wood species dried very long period’s and very low quality levels with method in conventional drying. So High

  12. Model electrochemical interfaces in ultra-high vacuum: solvent-induced surface potential profiles on Pt(111) from work-function measurements and infrared Stark effects

    Science.gov (United States)

    Kizhakevariam, Naushad; Villegas, Ignacio; Weaver, Michael J.

    1995-08-01

    The influence of various solvents upon the interfacial-potential profile on Pt(111) has been investigated by means of work-function changes and infrared frequency Stark shifts attending sequential-molecular dosing in ultra-high vacuum (UHV) at a suitably low temperature (ca. 100 K) with the primary objective of assessing the role of surface solvation in related electrochemical systems. The solvents examined — dichloromethane, benzene, acetone, acetonitrile, methanol, and ammonia — span a range of polarity and other solvating properties. These species were dosed onto both clean and CO-saturated Pt(111), the Stark shifts being evaluated for the CO stretching mode of terminally co-ordinated carbon monoxide. Marked decreases (≥ 1 eV) in the work function, Φ, and hence in the surface potential, φ, are observed on the addition of most solvents onto clean Pt(111). Milder yet still substantial Φ decreases are also observed for solvent dosage upon CO-saturated Pt(111). These latter Φ changes correlate approximately with the observed vCO frequency downshifts, suggesting that the latter property is also sensitive to the solvent-induced electrostatic interfacial field. The functional form of both the Φ decreases and the corresponding vCO frequency downshifts induced by solvent dosage provide insight into the dosage-dependent potential profile and its relationship to both the monolayer and multilayer solvent structure. The present findings are also briefly compared with corresponding vtCO - Φ data obtained for potassium atom dosing, where the surface potential is altered instead by varying the surface electronic charge in the presence of a given solvent. The underlying factors responsible for the surprisingly large solvent-induced surface potential shifts are discussed in detail, and the likely importance of the surface electronic charge distribution as well as solvent dipole orientation and adsorbate-metal charge sharing is pointed out.

  13. Analysis and Treatment of Common Faults of High Voltage Vacuum Contactor%高压真空接触器常见故障的处理及原因分析

    Institute of Scientific and Technical Information of China (English)

    盛明学

    2011-01-01

    High voltage vacuum contactors are widely used in high voltage power system of power plant. In order to help the field workers correctly and promptly treat the common faults of high voltage vacuum contactors, this paper introduced the working principle of high voltage vacuum contactor operating mechanism, detailedly described the common faults and treatment methods in previous operation and maintenance, and analyzed the causes of the faults. In addition, suggestions were offered to reduce the fault rate of high voltage vacuum contactors.%高压真空接触器在发电厂高压厂用电系统中应用广泛.若发生的故障处理不及时,将会直接影响发电厂机组的安全经济运行.为帮助现场工作人员正确、及时处理高压真空接触器的常见故障,笔者根据多年的实践经验,首先对高压真空接触器操作机构的工作原理进行简要叙述,然后重点对实际运行和检修维护中发现的故障及处理经过进行详细描述,对造成故障的原因进行分析,最后对如何降低高压真空接触器故障发生率提出建议.

  14. Industry-relevant magnetron sputtering and cathodic arc ultra-high vacuum deposition system for in situ x-ray diffraction studies of thin film growth using high energy synchrotron radiation.

    Science.gov (United States)

    Schroeder, J L; Thomson, W; Howard, B; Schell, N; Näslund, L-Å; Rogström, L; Johansson-Jõesaar, M P; Ghafoor, N; Odén, M; Nothnagel, E; Shepard, A; Greer, J; Birch, J

    2015-09-01

    We present an industry-relevant, large-scale, ultra-high vacuum (UHV) magnetron sputtering and cathodic arc deposition system purposefully designed for time-resolved in situ thin film deposition/annealing studies using high-energy (>50 keV), high photon flux (>10(12) ph/s) synchrotron radiation. The high photon flux, combined with a fast-acquisition-time (<1 s) two-dimensional (2D) detector, permits time-resolved in situ structural analysis of thin film formation processes. The high-energy synchrotron-radiation based x-rays result in small scattering angles (<11°), allowing large areas of reciprocal space to be imaged with a 2D detector. The system has been designed for use on the 1-tonne, ultra-high load, high-resolution hexapod at the P07 High Energy Materials Science beamline at PETRA III at the Deutsches Elektronen-Synchrotron in Hamburg, Germany. The deposition system includes standard features of a typical UHV deposition system plus a range of special features suited for synchrotron radiation studies and industry-relevant processes. We openly encourage the materials research community to contact us for collaborative opportunities using this unique and versatile scientific instrument.

  15. The vacuum strikes back

    CERN Multimedia

    2007-01-01

    "Modern physics has shown that the vacuum, previously thought of as a stated of total nothingness, is really a seething background of virtual particles springing in and out of eixstence until they can seize enough energy to materialize as "real" particles." (1,5 page)

  16. ISR vacuum system

    CERN Multimedia

    1971-01-01

    Some of the most important components of the vacuum system are shown. At the left, the rectangular box is a sputter-ion pump inside its bake-out oven. The assembly in the centre includes a sector valve, three roughing valves, a turbomolecular pump, a rotary backing pump and auxiliary equipment. At the right, the small elbow houses a Bayard-

  17. LEP Vacuum Chamber

    CERN Multimedia

    1983-01-01

    This is a cut-out of a LEP vacuum chamber for dipole magnets showing the beam channel and the pumping channel with the getter (NEG) strip and its insulating supports. A water pipe connected to the cooling channel can also be seen at the back.The lead radiation shield lining is also shown. See also 8305563X.

  18. Vacuum-assisted delivery

    Science.gov (United States)

    ... a handle on the cup to move the baby through the birth canal. When is Vacuum-assisted Delivery Needed? Even after your cervix is fully dilated ( ... delivers the baby's head, you will push the baby the rest of the way out. After delivery, you can hold your baby on your tummy ...

  19. ISR vacuum system

    CERN Multimedia

    1970-01-01

    A pressure of 5 x 10-11 Torr has been obtained repreatedly in this pilot section of the ISR vacuum system. The pilot section is 45 m long is pumped by 9 sputter-ion pumps pf 350 l/s pumping speed, and is baked out at 200 degrees C before each pump down.

  20. LEP vacuum chamber, prototype

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    Final prototype for the LEP vacuum chamber, see 8305170 for more details. Here we see the strips of the NEG pump, providing "distributed pumping". The strips are made from a Zr-Ti-Fe alloy. By passing an electrical current, they were heated to 700 deg C.

  1. The rotating quantum vacuum

    CERN Document Server

    Davies, Paul Charles William; Manogue, C A; Davies, Paul C W; Dray, Tevian; Manogue, Corinne A

    1996-01-01

    We derive conditions for rotating particle detectors to respond in a variety of bounded spacetimes and compare the results with the folklore that particle detectors do not respond in the vacuum state appropriate to their motion. Applications involving possible violations of the second law of thermodynamics are briefly addressed.

  2. Microstructure and properties of vacuum counter-pressure cast aluminum alloy

    OpenAIRE

    YAN Qing-song; Yu, Huan; WEI Bo-kang

    2006-01-01

    The microstructure and properties of vacuum counter-pressure cast aluminum alloy were studied. Results indicated that under the condition of vacuum counter-pressure, liquid melts fill mould cavity under the vacuum and crystallize under high pressure which have very good effect on nucleation and solidification feeding. Compared with gravity casting, the microstructure of vacuum counter-pressure cast aluminum alloy is much finer and more uniformly distributed. Mechanical properties of vacuum co...

  3. Vacuum packaging technology for mass production of uncooled IRFPAs

    Science.gov (United States)

    Ito, Takuya; Tokuda, Takayuki; Kimata, Masafumi; Abe, Hideyuki; Tokashiki, Naotaka

    2009-05-01

    We developed vacuum packaging equipment and low-cost vacuum packaging technology for the mass production of uncooled IRFPAs. The equipment consists of two chambers with identical construction. Two-chamber architecture provides flexibility in the vacuum packaging process, so we can bake the components and achieve getter activation by heating, stem/cap soldering, and cap/window soldering in a series under high-vacuum conditions. Heaters and component-holding jigs are made of graphite to assure rapid and uniform heating to 500°C. The batch size is 27 if we choose a 15-mm diameter TO8 package and can be increased by enlarging the graphite heater area. We also developed a micro-vacuum gauge to evaluate the vacuum level in encapsulated packages. The operation principle of this vacuum gauge is based on thermal conduction by air molecules. It can be integrated in IRFPA chips since the fabrication process is compatible with that for IRFPAs. We encapsulated the vacuum gauges in TO8 packages with our vacuum packaging equipment, and confirmed that the pressure in fabricated packages is sufficiently low for high performance IRFPA operation (<< 1 Pa) with the micro-vacuum gauges.

  4. 高负压劈核技术在硬核白内障复明手术中的效果观察%Effect of High Vacuum Phaco Chop Technique for Hard Nucleolus Cataract

    Institute of Scientific and Technical Information of China (English)

    卢建民

    2011-01-01

    Objective To observe the effect of high vacuum phaco chop technique for hard nucleolus cataract. Methods 51 cases (65 eyes) of hard nucleolus cataract were performed by high vacuum phaco chop. Results The best corrected visual acuity (BCVA) ≥ 0. 3 was in 56 eyes (86%) one day after operation. The best corrected visual acuity (BCVA) ≥ 0.3 was in 61 eyes (94%) one month after operation. 3 eyes had posterior capsule rupture in operation. Conclusion High vacuum phaco chop technique is safe and effective for hard nucleolus cataract.%目的观察高负压劈核技术在硬核白内障手术的效果.方法采用高负压下劈核技术对51例65眼硬核白内障进行超声乳化手术.结果术后1 d矫正视力≥0.3者56眼(86%),术后1个月矫正视力≥0.3者61眼(94%),后囊膜破裂3例.结论高负压劈核技术对硬核白内障具有安全高效的复明效果.

  5. Gas bearing operates in vacuum

    Science.gov (United States)

    Perkins, G. S.

    1975-01-01

    Bearing has restrictions to reduce air leaks and is connected to external pumpout facility which removes exhausted air. Token amount of air which is lost to vacuum is easily removed by conventional vacuum pump.

  6. Tritium handling in vacuum systems

    Energy Technology Data Exchange (ETDEWEB)

    Gill, J.T. [Monsanto Research Corp., Miamisburg, OH (United States). Mound Facility; Coffin, D.O. [Los Alamos National Lab., NM (United States)

    1986-10-01

    This report provides a course in Tritium handling in vacuum systems. Topics presented are: Properties of Tritium; Tritium compatibility of materials; Tritium-compatible vacuum equipment; and Tritium waste treatment.

  7. Research on vacuum membrane distillation technique disposing of high concentration inorganic salt reverse osmosis dense dewatering%减压膜蒸馏技术处理无机高盐 RO 浓排水研究

    Institute of Scientific and Technical Information of China (English)

    郭建中; 路全忠; 杨才伟

    2012-01-01

      针对无机高盐 RO 浓排水具有含盐量高难处理的特点,本文研究了减压膜蒸馏技术处理无机高盐RO 浓排水试验阶段中不同料液温度、真空度、流速对膜通量的影响.结果表明:料液温度、真空度、流速与膜通量存在相关性.随着料液温度和真空度的提高,膜通量会相应增加;随着料液流速的增加膜通量也有增加,但流速小于0.2 m/s 时对膜通量的影响明显,当流速大于0.2m/s 时对膜通量影响小%  Aimed at the characteristic of high salinity and difficult dispose of high concentration inorganic salt reverse osmosis dewatering, this paper studies the vacuum membrane distillation technique dispose of high concentration inorganic salt reverse osmosis dewatering, and analyse the influence of different vacuum, material fluid temperature, flow velocity to membrane flux. The result shows that there is a correlation between membrane flux and vacuum, material fluid temperature and flow velocity. With increasing of vacuum and material fluid temperature, membrane flux increased accordingly; and when the velocity increased and membrane flux increased at the same time. With the velocity was less than 0.2 m/s, the influence to membrane flux came to be obvious, when the velocity was above 0.2 m/s, the influence to membrane flux went light.

  8. Surge-damping vacuum valve

    Science.gov (United States)

    Bullock, Jack C.; Kelly, Benjamin E.

    1980-01-01

    A valve having a mechanism for damping out flow surges in a vacuum system which utilizes a slotted spring-loaded disk positioned adjacent the valve's vacuum port. Under flow surge conditions, the differential pressure forces the disk into sealing engagement with the vacuum port, thereby restricting the flow path to the slots in the disk damping out the flow surge.

  9. Vacuum system of SST-1 Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Ziauddin, E-mail: ziauddin@ipr.res.in [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382 428 (India); Pathan, Firozkhan; George, Siju; Semwal, Pratibha; Dhanani, Kalpesh; Paravastu, Yuvakiran; Thankey, Prashant; Ramesh, Gattu; Himabindu, Manthena; Pradhan, Subrata [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382 428 (India)

    2013-10-15

    Highlights: ► Air leaks developed during ongoing SST-1 cooldown campaign were detected online using RGA. ► The presence of N{sub 2} and O{sub 2} gases with the ratio of their partial pressures with ∼3.81:1 confirmed the air leaks. ► Baking of SST-1 was done efficiently by flowing hot N{sub 2} gas in C-channels welded on inner surfaces without any problem. ► In-house fabricated demountable bull nose couplers were demonstrated for high temperature and pressure applications. ► Cryopumping effect was observed when liquid helium cooled superconducting magnets reached below 63 K. -- Abstract: Vacuum chambers of Steady State Superconducting (SST-1) Tokamak comprises of the vacuum vessel and the cryostat. The plasma will be confined inside the vacuum vessel while the cryostat houses the superconducting magnet systems (TF and PF coils), LN{sub 2} cooled thermal shields and hydraulics for these circuits. The vacuum vessel is an ultra-high (UHV) vacuum chamber while the cryostat is a high-vacuum (HV) chamber. In order to achieve UHV inside the vacuum vessel, it would be baked at 150 °C for longer duration. For this purpose, U-shaped baking channels are welded inside the vacuum vessel. The baking will be carried out by flowing hot nitrogen gas through these channels at 250 °C at 4.5 bar gauge pressure. During plasma operation, the pressure inside the vacuum vessel will be raised between 1.0 × 10{sup −4} mbar and 1.0 × 10{sup −5} mbar using piezoelectric valves and control system. An ultimate pressure of 4.78 × 10{sup −6} mbar is achieved inside the vacuum vessel after 100 h of pumping. The limitation is due to the development of few leaks of the order of 10{sup −5} mbar l/s at the critical locations of the vacuum vessel during baking which was confirmed with the presence of nitrogen gas and oxygen gas with the ratio of ∼3.81:1 indicating air leak. Similarly an ultimate vacuum of 2.24 × 10{sup −5} mbar is achieved inside the cryostat. Baking of the

  10. Infra-red reflection absorption spectroscopic study on adsorption structures of acrolein on polycrystalline gold and Au(111) surfaces under ultra-high vacuum conditions

    Science.gov (United States)

    Akita, M.; Osaka, N.; Itoh, K.

    1998-05-01

    Infra-red reflection absorption (IRA) spectra were measured at 80 K under ultra-high vacuum conditions for acrolein adsorbed on two kinds of gold films; Au(111) and polycrystalline gold surfaces. Upon increasing the amount of exposure from 0.02 to 200 L (1 L=1×10 -6 Torr·s), the adsorbate at Au(111) gave rise to a series of sharp IRA bands due to a CH 2 out-of-plane wagging vibration [ ω(CH 2)] successively, indicating discrete adsorption states, i.e. 964 (type 1)→978(type 1')→991(type 2)→1003 cm -1(type 3). All these states have the molecular plane parallel to the surface; type 1 is in an isolated state, and type 2 is in an associated state with a two-dimensional arrangement, whereas type 3 forms an ordered multilayered structure. Type 1' was tentatively assigned either to a trapped state at step sites or to an associated state forming small oligomers at the surface. Only type 3 gives rise to IRA bands due to ν(CO), which appears at 1677 cm -1 as a singlet at relatively small exposure levels and splits into doublets, giving the 1686 and 1672 cm -1 components at 2.0 L. The doublets were explained as being due to a crystal field splitting, which conforms to the fact that the adsorbate forms an ordered three-dimensional arrangement. The IRA spectrum of type 3 is readily converted to that of a more stable polycrystalline state upon increasing the temperature from 80 to 100 K. Thus, type 3 is a thermodynamically metastable state. Acrolein adsorbed on a polycrystalline gold film assumes an amorphous state in the exposure level of 0.06-4.8 L, giving broad IRA bands due to ν(CO) and ω(CH 2) in the 1686-1699 and 974-991 cm -1 regions, respectively. The IRA spectra of acrolein adsorbed on Ag(111) were also measured, which indicated that the adsorbates exist in a less ordered state than those on Au(111), although a multilayered structure gives IRA features that are almost identical with those of type 3.

  11. HiPTI - High Performance Thermal Insulation, Annex 39 to IEA/ECBCS-Implementing Agreement. Vacuum insulation in the building sector. Systems and applications

    Energy Technology Data Exchange (ETDEWEB)

    Binz, A.; Moosmann, A.; Steinke, G.; Schonhardt, U.; Fregnan, F. [Fachhochschule Nordwestschweiz (FHNW), Muttenz (Switzerland); Simmler, H.; Brunner, S.; Ghazi, K.; Bundi, R. [Swiss Federal Laboratories for Materials Testing and Research (EMPA), Duebendorf (Switzerland); Heinemann, U.; Schwab, H. [ZAE Bayern, Wuerzburg (Germany); Cauberg, H.; Tenpierik, M. [Delft University of Technology, Delft (Netherlands); Johannesson, G.; Thorsell, T. [Royal Institute of Technology (KTH), Stockholm (Sweden); Erb, M.; Nussbaumer, B. [Dr. Eicher und Pauli AG, Basel and Bern (Switzerland)

    2005-07-01

    This final report on vacuum insulation panels (VIP) presents and discusses the work done under IEA/Energy Conservation in Buildings and Community Systems (ECBCS) Annex 39, subtask B on the basis of a wide selection of reports from practice. The report shows how the building trade deals with this new material today, the experience gained and the conclusions drawn from this work. As well as presenting recommendations for the practical use of VIP, the report also addresses questions regarding the effective insulation values to be expected with current VIP, whose insulation performance is stated as being a factor of five to eight times better than conventional insulation. The introduction of this novel material in the building trade is discussed. Open questions and risks are examined. The fundamentals of vacuum insulation panels are discussed and the prerequisites, risks and optimal application of these materials in the building trade are examined.

  12. Ultrahigh-vacuum facility for high-resolution grazing-angle X-ray diffraction at a vertical wiggler source of synchrotron radiation.

    Science.gov (United States)

    Sakata, O; Tanaka, Y; Nikolaenko, A M; Hashizume, H

    1998-07-01

    A versatile ultrahigh-vacuum chamber has been designed for grazing-angle X-ray standing-wave and diffraction experiments at the vertical wiggler source of the Photon Factory. Unlike at other sources, the vertically polarized X-rays from the wiggler favour the use of a horizontal scattering geometry. The X-ray chamber is equipped with a hemispherical beryllium window, which allows any scattering angle to be attained and secondary emissions to be measured. The chamber is of a compact design, sitting on a precision rotary table which is rotated for scans. Samples are introduced from a portable vessel. The whole procedure can be performed in a vacuum better than 10(-7) Pa. The system has successfully been applied to a grazing-angle X-ray standing-wave experiment, which determined the dimer bond length and the domain structure of Si(001) surfaces deposited with monolayer arsenic.

  13. Cold Vacuum Drying (CVD) Set Point Determination

    Energy Technology Data Exchange (ETDEWEB)

    PHILIPP, B.L.

    2000-03-21

    The Safety Class Instrumentation and Control (SCIC) system provides active detection and response to process anomalies that, if unmitigated, would result in a safety event. Specifically, actuation of the SCIC system includes two portions. The portion which isolates the MCO and initiates the safety-class helium (SCHe) purge, and the portion which detects and stops excessive heat input to the MCO on high tempered water MCO inlet temperature. For the MCO isolation and purge, the SCIC receives signals from MCO pressure (both positive pressure and vacuum), helium flow rate, bay high temperature switches, seismic trips and time under vacuum trips.

  14. A Rotating Quantum Vacuum

    CERN Document Server

    De Lorenci, V A

    1996-01-01

    We investigate which mapping we have to use to compare measurements made in a rotating frame to those made in an inertial frame. Using a "Lorentz-like" coordinate transformation we obtain that creation-anihilation operators of a massless scalar field in the rotating frame are not the same as those of an inertial observer. This leads to a new vacuum state (a rotating vacuum) which is a superposition of positive and negative frequency Minkowski particles. After this, introducing an apparatus device coupled linearly with the field we obtain that there is a strong correlation between number of rotating particles (in a given state) obtained via canonical quantization and via response function of the rotating detector. Finally, we analyse polarization effects in circular accelerators in the proper frame of the electron making a connection with the inertial frame point of view.

  15. Dry vacuum pumps

    Science.gov (United States)

    Sibuet, R.

    2008-05-01

    For decades and for ultimate pressure below 1 mbar, oil-sealed Rotary Vane Pumps have been the most popular solution for a wide range of vacuum applications. In the late 80ies, Semiconductor Industry has initiated the development of the first dry roughing pumps. Today SC applications are only using dry pumps and dry pumping packages. Since that time, pumps manufacturers have developed dry vacuum pumps technologies in order to make them attractive for other applications. The trend to replace lubricated pumps by dry pumps is now spreading over many other market segments. For the Semiconductor Industry, it has been quite easy to understand the benefits of dry pumps, in terms of Cost of Ownership, process contamination and up-time. In this paper, Technology of Dry pumps, its application in R&D/industries, merits over conventional pumps and future growth scope will be discussed.

  16. 高压真空断路器的检修与维护%Maintenance of High Voltage Vacuum Circuit Breaker

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    Vacuum circuit breaker has advantages of large capacity, good arc extin-guishing performance, long life of contact head, a small amount of operation maintenance and long maintenance cycle. Therefore, the vacuum circuit breaker has been widely used in every substation of Jigang Group Co., Ltd. The problems in maintenance of the vacuum circuit breaker are analyzed, and the improvement suggestions and measures are offered.%  真空断路器具有开断容量大、灭弧性能好、触头寿命长、运行维护量小、检修周期长等特点。因此,真空断路器在济钢各个变电站得到了广泛的应用。针对济钢内部真空断路器维护检修中出现的一些问题进行分析,并提出改进建议和措施。

  17. Testing of improved polyimide actuator rod seals at high temperature and under vacuum conditions for use in advanced aircraft hydraulic systems

    Science.gov (United States)

    Sellereite, B. K.; Waterman, A. W.; Nelson, W. G.

    1974-01-01

    Polyimide second-stage rod seals were evaluated to determine their suitability for applications in space station environments. The 6.35-cm (2.5-in.)K-section seal was verified for thermal cycling operation between room temperature and 478 K (400 F) and for operation in a 133 micron PA(0.000001 mm Hg) vacuum environment. The test seal completed the scheduled 96 thermal cycles and 1438 hr in vacuum with external rod seal leakage well within the maximum allowable of two drops per 25 actuation cycles. At program completion, the seals showed no signs of structural degradation. Posttest inspection showed the seals retained a snug fit against the shaft and housing walls, indicating additional wear life capability. Evaluation of a molecular flow section during vacuum testing, to inhibit fluid loss through vaporization, showed it to be beneficial with MIL-H-5606, a petroleum-base fluid, in comparison with MIL-H-83282, a synthetic hydrocarbon-base fluid.

  18. PARAFFIN SEPARATION VACUUM DISTILLATION

    Directory of Open Access Journals (Sweden)

    Zaid A. Abdulrahman

    2013-05-01

    Full Text Available Simulated column performance curves were constructed for existing paraffin separation vacuum distillation column in LAB plant (Arab Detergent Company/Baiji-Iraq. The variables considered in this study are the thermodynamic model option, top vacuum pressure, top and bottom temperatures, feed temperature, feed composition & reflux ratio. Also simulated columns profiles for the temperature, vapor & liquid flow rates composition were constructed. Four different thermodynamic model options (SRK, TSRK, PR, and ESSO were used, affecting the results within 1-25% variation for the most cases.The simulated results show that about 2% to 8 % of paraffin (C10, C11, C12, & C13 present at the bottom stream which may cause a problem in the LAB plant. The major variations were noticed for the top temperature & the  paraffin weight fractions at bottom section with top vacuum pressure. The bottom temperature above 240 oC is not recommended because the total bottom flow rate decreases sharply, where as  the weight fraction of paraffins decrease slightly. The study gives evidence about a successful simulation with CHEMCAD

  19. Bake-Out Mobile Controls for Large Vacuum Systems

    CERN Document Server

    Blanchard, S; Gomes, P; Pereira, H; Kopylov, L; Merker, S; Mikheev, M

    2014-01-01

    Large vacuum systems at CERN (Large Hadron Collider - LHC, Low Energy Ion Rings - LEIR...) require bake-out to achieve ultra-high vacuum specifications. The bake-out cycle is used to decrease the outgassing rate of the vacuum vessel and to activate the Non-Evaporable Getter (NEG) thin film. Bake-out control is a Proportional-Integral-Derivative (PID) regulation with complex recipes, interlocks and troubleshooting management and remote control. It is based on mobile Programmable Logic Controller (PLC) cabinets, fieldbus network and Supervisory Control and Data Acquisition (SCADA) application. The CERN vacuum installations include more than 7 km of baked vessels; using mobile cabinets reduces considerably the cost of the control system. The cabinets are installed close to the vacuum vessels during the time of the bake-out cycle. Mobile cabinets can be used in any of the CERN vacuum facilities. Remote control is provided through a fieldbus network and a SCADA application

  20. Four wave mixing as a probe of the vacuum

    Science.gov (United States)

    Tennant, Daniel M.

    2016-06-01

    Much attention has been paid to the quantum structure of the vacuum. Higher order processes in quantum electrodynamics are strongly believed to cause polarization and even breakdown of the vacuum in the presence of strong fields soon to be accessible in high intensity laser experiments. Less explored consequences of strong field electrodynamics include effects from Born-Infeld type of electromagnetic theories, a nonlinear electrodynamics that follows from classical considerations as opposed to coupling to virtual fluctuations. In this article, I will demonstrate how vacuum four wave mixing has the possibility to differentiate between these two types of vacuum responses: quantum effects on one hand and nonlinear classical extensions on the other.

  1. Cold Vacuum Drying (CVD) Set Point Determination

    Energy Technology Data Exchange (ETDEWEB)

    PHILIPP, B.L.

    2000-09-04

    The Safety Class Instrumentation and Control (SCIC) system provides active detection and response to process anomalies that, if unmitigated, would result in a safety event. Specifically, actuation of the SCIC system includes two portions. The portion which isolates the MCO and initiates the safety-class helium (SCHe) purge, and the portion which detects and stops excessive heat input to the MCO annulus on high Tempered Water (TW) inlet temperature. For the MCO isolation and purge, the SCIC receives MCO pressure (both positive pressure and vacuum), helium flow rate, bay high temperature switch status, seismic trip status, and time-under-vacuum trips signals. The SCIC system will isolate the MCO and start an SCHe system purge if any of the following occur. (1) Isolation and purge from one of the SCHe ''isolation'' and ''purge'' buttons is manually initiated (administratively controlled). (2) The first vacuum cycle exceeds 8 hours at vacuum, or any subsequent vacuum cycle exceeds 4 hours at vacuum without re-pressurizing the MCO for a minimum of 4 hours. (This is referred to as the 8/4/4 requirement and provides thermal equilibrium within the MCO.) (3) MCO is below atmospheric pressure and the helium flow is below the minimum required to keep hydrogen less than 4% by volume. (When MCO pressure is below 12 torr there is insufficient hydrogen to exceed the 4% level and therefore no purge is required. A five minute time delay on low flow allows flow to be stopped in order to reach < 12 torr.) (4) The duration for the transition from above atmospheric pressure to vacuum (time to reach pressure below -11.7 psig [{approx}155 torr]) exceeds 5 minutes. (5) The duration for the transition from vacuum (below -11.1 psig [{approx}185 torr]) back to pressure [greater than 0.5 psig] exceeds 5 minutes. (6) MCO reaches a vacuum state (<0.5 psig) without an adequate, verified purge volume. (The MCO must be maintained above atmospheric pressure

  2. Testing of a vacuum insulated flexible line with flowing liquid nitrogen during the loss of insulating vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Demko, Jonathan A [ORNL; Duckworth, Robert C [ORNL; Gouge, Michael J [ORNL; Roden, Mark L [ORNL

    2008-01-01

    Long length vacuum insulated lines are used to carry flowing liquid nitrogen in several high temperature superconducting cable projects. An important, but rare, failure scenario is the abrupt or catastrophic loss of the thermal insulating vacuum producing a rapid increase in heat transfer to the liquid nitrogen stream. In this experimental investigation, a vacuum superinsulated 3 inch by 5 inch NPS (88.9 mm by 141.3 mm) flexible cryostat is subjected to an abrupt loss of vacuum in order to measure the thermal response of a flowing liquid nitrogen stream and the temperature response of the cryostat. The measured outlet stream temperature has a slight peak shortly after the loss of vacuum incident and decreases as the cryostat warms up. The heat loads measured before and after the vacuum loss event are reported. Measurements of the temperatures in the multi-layer superinsulation are also discussed.

  3. Compressed Air/Vacuum Transportation Techniques

    Science.gov (United States)

    Guha, Shyamal

    2011-03-01

    General theory of compressed air/vacuum transportation will be presented. In this transportation, a vehicle (such as an automobile or a rail car) is powered either by compressed air or by air at near vacuum pressure. Four version of such transportation is feasible. In all versions, a ``c-shaped'' plastic or ceramic pipe lies buried a few inches under the ground surface. This pipe carries compressed air or air at near vacuum pressure. In type I transportation, a vehicle draws compressed air (or vacuum) from this buried pipe. Using turbine or reciprocating air cylinder, mechanical power is generated from compressed air (or from vacuum). This mechanical power transferred to the wheels of an automobile (or a rail car) drives the vehicle. In type II-IV transportation techniques, a horizontal force is generated inside the plastic (or ceramic) pipe. A set of vertical and horizontal steel bars is used to transmit this force to the automobile on the road (or to a rail car on rail track). The proposed transportation system has following merits: virtually accident free; highly energy efficient; pollution free and it will not contribute to carbon dioxide emission. Some developmental work on this transportation will be needed before it can be used by the traveling public. The entire transportation system could be computer controlled.

  4. Recent advances in vacuum sciences and applications

    Science.gov (United States)

    Mozetič, M.; Ostrikov, K.; Ruzic, D. N.; Curreli, D.; Cvelbar, U.; Vesel, A.; Primc, G.; Leisch, M.; Jousten, K.; Malyshev, O. B.; Hendricks, J. H.; Kövér, L.; Tagliaferro, A.; Conde, O.; Silvestre, A. J.; Giapintzakis, J.; Buljan, M.; Radić, N.; Dražić, G.; Bernstorff, S.; Biederman, H.; Kylián, O.; Hanuš, J.; Miloševič, S.; Galtayries, A.; Dietrich, P.; Unger, W.; Lehocky, M.; Sedlarik, V.; Stana-Kleinschek, K.; Drmota-Petrič, A.; Pireaux, J. J.; Rogers, J. W.; Anderle, M.

    2014-04-01

    Recent advances in vacuum sciences and applications are reviewed. Novel optical interferometer cavity devices enable pressure measurements with ppm accuracy. The innovative dynamic vacuum standard allows for pressure measurements with temporal resolution of 2 ms. Vacuum issues in the construction of huge ultra-high vacuum devices worldwide are reviewed. Recent advances in surface science and thin films include new phenomena observed in electron transport near solid surfaces as well as novel results on the properties of carbon nanomaterials. Precise techniques for surface and thin-film characterization have been applied in the conservation technology of cultural heritage objects and recent advances in the characterization of biointerfaces are presented. The combination of various vacuum and atmospheric-pressure techniques enables an insight into the complex phenomena of protein and other biomolecule conformations on solid surfaces. Studying these phenomena at solid-liquid interfaces is regarded as the main issue in the development of alternative techniques for drug delivery, tissue engineering and thus the development of innovative techniques for curing cancer and cardiovascular diseases. A review on recent advances in plasma medicine is presented as well as novel hypotheses on cell apoptosis upon treatment with gaseous plasma. Finally, recent advances in plasma nanoscience are illustrated with several examples and a roadmap for future activities is presented.

  5. Vacuum packaging design and analysis for UFPA

    Science.gov (United States)

    Liu, Dafu; Xu, Qinfei

    2010-10-01

    Uncooled focal plane array (UFPA) has broad application prospects in civilian and space because it's cheaper, more compact and high reliability. Many research institutes and companies have carried out the research of uncooled focal plane array. This paper shows a vacuum package design of UFPA, and its architecture will be given. The assembly is an all-metal vacuum package, which has been proven rugged and reliable. Out-gassing, permeation, evaporator, and air leak are factors to reduce the component vacuum lifetime. Theoretical analysis shows that material out-gassing is the main factor of pressure rise inside package. Theoretical analysis and calculation show that designed metallic structure can meet the need of 10-years life.

  6. Vacuum System for HL-2A Tokamak

    Institute of Scientific and Technical Information of China (English)

    曹曾; 崔成和; 刘德权; 蔡萧; 高霄燕

    2005-01-01

    The vacuum system for HL-2A was built in 2003. The test results indicated that this system is feasible. It consists of three main parts: a pumping system, a pumping divertor and a glow discharge cleaning (GDC) system. For the pumping system, there are three main functions:(1) evacuating the vacuum vessel thus to produce an ultra high vacuum, (2) removal of impurities released during baking and (3) pumping during GDC. The pumping divertor controls the particles at the plasma edge and the GDC system provides a clean wall conditioning. During the first campaign of physical trial experiment on HL-2A, the ultimate pressure reached 4.6×10-6 Pa, and of ASDEX.

  7. Vacuum interrupters and thyratrons as opening switches

    Science.gov (United States)

    Honig, E. M.

    High power opening switches for inductive storage for large scale energy storage applications are described. The triggered vacuum interrupter and the magnetically quenched thyratrons are discussed. By electrically retriggering the discharge in the vacuum interrupter between pulses, the dependence on mechanical motion is eliminated. This should enable repetition rate operation at 10 to 15 kHz while still maintaining the vacuum interrupter's proven interrupting performance of tens of kiloamps at tens of kilovolts. The magnetically quenched thyratron uses a cross magnetic field to raise the switch impedance by decreasing the electron mobility and driving the discharge into an arc chute wall where it is quenched. Attempts to understand the basic mechanisms involved and to increase the switch, ratings, and particularly the conduction time, are discussed.

  8. Mathematical Model for the Continuous Vacuum Drying

    Institute of Scientific and Technical Information of China (English)

    DAI Hui-liang

    2002-01-01

    An improved mathematical model for the continuous vacuum drying of highly viscous and heatsensitive foodstuffs was proposed, The process of continuous vacuum drying was presented as a moving boundary problem of moisture evaporation in cylindrical coordinates. Boundary condition of the first kind for the known functional dependence of the drying body surface temperature on time was considered. Finally, the appropriate system of differential equations was solved numerically and the values of drying rate, integral moisture content of the material, moving boundary position as well as temperature in any point of the material and at any moment time were obtained. This procedure was applied to continuous vacuum drying of foods such as natural cheese and fresh meat paste.

  9. Friedmann cosmology with decaying vacuum density

    CERN Document Server

    Borges, H A

    2005-01-01

    Among the several proposals to solve the incompatibility between the observed small value of the cosmological constant and the huge value obtained by quantum field theories, we can find the idea of a decaying vacuum energy density, leading from high values at early times of universe evolution to the small value observed nowadays. In this paper we consider a variation law for the vacuum density recently proposed by Schutzhold on the basis of quantum field estimations in the curved, expanding background, characterized by a vacuum density proportional to the Hubble parameter. We show that, in the context of an isotropic and homogeneous, spatially flat model, the corresponding solutions retain the well established features of the standard cosmology, and, in addition, are in accordance with the observed cosmological parameters. Our scenario presents an initial phase dominated by radiation, followed by a dust era long enough to permit structure formation, and by an epoch dominated by the cosmological term, which te...

  10. Development of vacuum die-casting process

    Institute of Scientific and Technical Information of China (English)

    Masashi Uchida

    2009-01-01

    The vacuum die-casting process, started 25 years ago in Japan, has been widely applied. This technology contributes very much to improvement of castings quality. The main factor causing the defects of die castings is the trapped air in the mold cavity, while the key technology of vacuum die-casting process is to avoid the trapped air effectively by evacuating the cavity before casting. At the same time, due to the shot speed and the casting pressure reduced in half, the service life of the die is prolonged and the productivity is enhanced, as well. Vacuum die-casting process is of great significance in improving the die castings quality and making up the shortcomings of super-high-speed shot casting.

  11. Ultra-low birefringence dodecagonal vacuum glass cell

    CERN Document Server

    Brakhane, Stefan; Meschede, Dieter; Moon, Geol; Robens, Carsten; Alberti, Andrea

    2015-01-01

    We eport on an ultra-low birefringence dodecagonal glass cell for ultra-high vacuum applications. The epoxy-bonded trapezoidal windows of the cell are made of SF57 glass, which exhibits a very low stress-induced birefringence. We characterize the birefringence $\\Delta n$ of each window with the cell under vacuum conditions, obtaining values around $\

  12. Vacuum bell therapy

    Science.gov (United States)

    Sesia, Sergio

    2016-01-01

    Background For specific therapy to correct pectus excavatum (PE), conservative treatment with the vacuum bell (VB) was introduced more than 10 years ago in addition to surgical repair. Preliminary results using the VB were encouraging. We report on our 13-year experience with the VB treatment including the intraoperative use during the Nuss procedure and present some technical innovations. Methods A VB with a patient-activated hand pump is used to create a vacuum at the anterior chest wall. Three different sizes of vacuum bells, as well as a model fitted for young women, exist. The appropriate size is selected according to the individual patient’s age and ventral surface. The device should be used at home for a minimum of 30 minutes (twice a day), and may be used up to a maximum of several hours daily. The intensity of the applied negative pressure can be evaluated with an integrated pressure gauge during follow-up visits. A prototype of an electronic model enables us to measure the correlation between the applied negative pressure and the elevation of the anterior chest wall. Results Since 2003, approx. 450 patients between 2 to 61 years of age started the VB therapy. Age and gender specific differences, depth of PE, symmetry or asymmetry, and concomitant malformations such as scoliosis and/or kyphosis influence the clinical course and success of VB therapy. According to our experience, we see three different groups of patients. Immediate elevation of the sternum was confirmed thoracoscopically during the Nuss procedure in every patient. Conclusions The VB therapy has been established as an alternative therapeutic option in selected patients suffering from PE. The initial results up to now are encouraging, but long-term results comprising more than 15 years are so far lacking, and further evaluation and follow-up studies are necessary. PMID:27747177

  13. Plasmons in QED vacuum

    Science.gov (United States)

    Petrov, E. Yu.; Kudrin, A. V.

    2016-09-01

    The problem of longitudinal oscillations of an electric field and a charge polarization density in a quantum electrodynamics (QED) vacuum is considered. Within the framework of semiclassical analysis, we calculate time-periodic solutions of bosonized (1 +1 )-dimensional QED (massive Schwinger model). Applying the Bohr-Sommerfeld quantization condition, we determine the mass spectrum of charge-zero bound states (plasmons) which correspond in quantum theory to the found classical solutions. We show that the existence of such plasmons does not contradict any fundamental physical laws and study qualitatively their excitation in a (3 +1 )-dimensional real world.

  14. Vacuum ultraviolet spectroscopy I

    CERN Document Server

    Samson, James A; Lucatorto, Thomas

    1998-01-01

    This volume is for practitioners, experimentalists, and graduate students in applied physics, particularly in the fields of atomic and molecular physics, who work with vacuum ultraviolet applications and are in need of choosing the best type of modern instrumentation. It provides first-hand knowledge of the state-of-the-art equipment sources and gives technical information on how to use it, along with a broad reference bibliography.Key Features* Aimed at experimentalists who are in need of choosing the best type of modern instrumentation in this applied field* Contains a detailed chapter on la

  15. LHC vacuum system

    CERN Document Server

    Gröbner, Oswald

    1999-01-01

    The Large Hadron Collider (LHC) project, now in the advanced construction phase at CERN, comprises two proton storage rings with colliding beams of 7-TeV energy. The machine is housed in the existing LEP tunnel with a circumference of 26.7 km and requires a bending magnetic field of 8.4 T with 14-m long superconducting magnets. The beam vacuum chambers comprise the inner 'cold bore' walls of the magnets. These magnets operate at 1.9 K, and thus serve as very good cryo-pumps. In order to reduce the cryogenic power consumption, both the heat load from synchrotron radiation emitted by the proton beams and the resistive power dissipation by the beam image currents have to be absorbed on a 'beam screen', which operates between 5 and 20 K and is inserted inside the vacuum chamber. The design of this beam screen represents a technological challenge in view of the numerous and often conflicting requirements and the very tight mechanical tolerances imposed. The synchrotron radiation produces strong outgassing from the...

  16. Compact Vacuum Pump for Titan Lander Missions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — For a number of years Creare has developed, fabricated, and tested highly miniaturized, high vacuum pumps specifically designed for mass spectrometers used on NASA...

  17. Vacuum metastability with black holes

    Energy Technology Data Exchange (ETDEWEB)

    Burda, Philipp [Centre for Particle Theory, Durham University,South Road, Durham, DH1 3LE (United Kingdom); Gregory, Ruth [Centre for Particle Theory, Durham University,South Road, Durham, DH1 3LE (United Kingdom); Perimeter Institute, 31 Caroline Street North,Waterloo, ON, N2L 2Y5 (Canada); Moss, Ian G. annd [School of Mathematics and Statistics, Newcastle University,Newcastle Upon Tyne, NE1 7RU (United Kingdom)

    2015-08-24

    We consider the possibility that small black holes can act as nucleation seeds for the decay of a metastable vacuum, focussing particularly on the Higgs potential. Using a thin-wall bubble approximation for the nucleation process, which is possible when generic quantum gravity corrections are added to the Higgs potential, we show that primordial black holes can stimulate vacuum decay. We demonstrate that for suitable parameter ranges, the vacuum decay process dominates over the Hawking evaporation process. Finally, we comment on the application of these results to vacuum decay seeded by black holes produced in particle collisions.

  18. Pseudo-redundant vacuum energy

    CERN Document Server

    Batra, Puneet; Hui, Lam; Kabat, Daniel

    2008-01-01

    We discuss models that can account for today's dark energy. The underlying cosmological constant may be Planck scale but starts as a redundant coupling which can be eliminated by a field redefinition. The observed vacuum energy arises when the redundancy is explicitly broken, say by a non-minimal coupling to curvature. We give a recipe for constructing models, including R + 1/R type models, that realize this mechanism and satisfy all solar system constraints on gravity. A similar model, based on Gauss-Bonnet gravity, provides a technically natural explanation for dark energy and exhibits an interesting see-saw behavior: a large underlying cosmological constant gives rise to both low and high curvature solutions. Such models could be statistically favored in the string landscape.

  19. Effect of vacuum conditions and plasma concentration on the chemical composition and adhesion of vacuum-plasma coatings

    Science.gov (United States)

    Borisov, D. P.; Kuznetsov, V. M.; Slabodchikov, V. A.

    2015-11-01

    The paper reports on the chemical composition of titanium nitride (TiN) and silicon (Si) coatings deposited with a new technological vacuum plasma setup which comprises magnetron sputtering systems, arc evaporators, and an efficient plasma generator. It is shown that due to highly clean vacuum conditions and highly clean surface treatment in the gas discharge plasma, both the coating-substrate interface and the coatings as such are almost free from oxygen and carbon. It is found that the coating-substrate interface represents a layer of thickness ≥ 60 nm formed through vacuum plasma mixing of the coating and substrate materials. The TiN coatings obtained on the new equipment display a higher adhesion compared to brass coatings deposited by industrial technologies via intermediate titanium oxide layers. It is concluded that the designed vacuum plasma equipment allows efficient surface modification of materials and articles by vacuum plasma immersion processes.

  20. THERMOCOUPLE VACUUM GAUGE

    Science.gov (United States)

    Price, G.W.

    1954-08-01

    A protector device is described for use in controlling the pressure within a cyclotron. In particular, an electrical circuit functions to actuate a vacuum pump when a predetermined low pressure is reached and disconnect the pump when the pressure increases abcve a certain value. The principal feature of the control circuit lies in the use of a voltage divider network at the input to a relay control tube comprising two parallel, adjustable resistances wherein one resistor is switched into the circuit when the relay connects the pump to a power source. With this arrangement the relay is energized at one input level received from a sensing element within the cyclotron chamber and is de-energized when a second input level, representing the higher pressure limit, is reached.

  1. Vacuum Energy Sequestering and Graviton Loops

    CERN Document Server

    Kaloper, Nemanja

    2016-01-01

    We recently formulated a local mechanism of vacuum energy sequester. This mechanism automatically removes all matter loop contributions to vacuum energy from the stress energy tensor which sources the curvature. Here we adapt the local vacuum energy sequestering mechanism to also cancel all the vacuum energy loops involving virtual gravitons, in addition to the vacuum energy generated by matter fields alone.

  2. Vacuum Energy Sequestering and Graviton Loops

    OpenAIRE

    Kaloper, Nemanja; Padilla, Antonio

    2016-01-01

    We recently formulated a local mechanism of vacuum energy sequester. This mechanism automatically removes all matter loop contributions to vacuum energy from the stress energy tensor which sources the curvature. Here we adapt the local vacuum energy sequestering mechanism to also cancel all the vacuum energy loops involving virtual gravitons, in addition to the vacuum energy generated by matter fields alone.

  3. Vacuum Gas Tungsten Arc Welding

    Science.gov (United States)

    Weeks, J. L.; Todd, D. T.; Wooten, J. R.

    1997-01-01

    A two-year program investigated vacuum gas tungsten arc welding (VGTAW) as a method to modify or improve the weldability of normally difficult-to-weld materials. After a vacuum chamber and GTAW power supply were modified, several difficult-to-weld materials were studied and key parameters developed. Finally, Incoloy 903 weld overlays were produced without microfissures.

  4. Vacuum enhanced cutaneous biopsy instrument

    Science.gov (United States)

    Collins, Joseph

    2000-01-01

    A syringe-like disposable cutaneous biopsy instrument equipped with a tubular blade at its lower end, and designed so that a vacuum is created during use, said vacuum serving to retain undeformed a plug of tissue cut from a patient's skin.

  5. ULTRARAPID VACUUM-MICROWAVE HISTOPROCESSING

    NARCIS (Netherlands)

    KOK, LP; BOON, ME

    1995-01-01

    A novel histoprocessing method for paraffin sections is presented in which the combination of vacuum and microwave exposure is the key element. By exploiting the decrease in boiling temperature under vacuum, the liquid molecules in the tissues have been successfully extracted and exchanged at relati

  6. ULTRARAPID VACUUM-MICROWAVE HISTOPROCESSING

    NARCIS (Netherlands)

    KOK, LP; BOON, ME

    A novel histoprocessing method for paraffin sections is presented in which the combination of vacuum and microwave exposure is the key element. By exploiting the decrease in boiling temperature under vacuum, the liquid molecules in the tissues have been successfully extracted and exchanged at

  7. Breather cloth for vacuum curing

    Science.gov (United States)

    Reed, M. W.

    1979-01-01

    Finely-woven nylon cloth that has been treated with Teflon improves vacuum adhesive bonding of coatings to substrates. Cloth is placed over coating; entire assembly, including substrate, coating, and cloth, is placed in plastic vacuum bag for curing. Cloth allows coating to "breathe" when bag is evacuated. Applications include bonding film coatings to solar concentrators and collectors.

  8. Research on high flow bidirectional sealed three vacuum eccentric butterfly valves design research%高流量双向密封三偏心真空蝶阀的设计

    Institute of Scientific and Technical Information of China (English)

    陈五星

    2012-01-01

    通过Solidworks软件对高流量双向密封三偏心真空蝶阀进行整体建模,论述了高流量双向密封三偏心真空蝶阀的结构特点。运用COSMOS及CoSMOSFLOWWORKS分析了蝶阀承压部件应力,并对不同开度下的流场进行模拟,为绘制流量特性曲线及求解不同开度下的K值提供了可靠的参数。%This paper uses Solidworks software to high flow bidirectional sealed three vacuum eccentric butterfly valve for the whole modeling, analysis of the high flow of two-way sealing structure characteristics of three vacuum eccentric butterfly valves, and the use of COSMOS and COSMOSFLOWWORKS butterfly valve on pressure parts stress analysis, to different degrees under the flow field simulation, for the latter part of drawing the flow characteristic curve and solving different opening degree under the Kv value provides reliable parameters.

  9. Hadron Contribution to Vacuum Polarisation

    CERN Document Server

    Davier, M; Malaescu, B; Zhang, Z

    2016-01-01

    Precision tests of the Standard Theory require theoretical predictions taking into account higher-order quantum corrections. Among these vacuum polarisation plays a predominant role. Vacuum polarisation originates from creation and annihilation of virtual particle–antiparticle states. Leptonic vacuum polarisation can be computed from quantum electrodynamics. Hadronic vacuum polarisation cannot because of the non-perturbative nature of QCD at low energy. The problem is remedied by establishing dispersion relations involving experimental data on the cross section for e+ e− annihilation into hadrons. This chapter sets the theoretical and experimental scene and reviews the progress achieved in the last decades thanks to more precise and complete data sets. Among the various applications of hadronic vacuum polarisation calculations, two are emphasised: the contribution to the anomalous magnetic moment of the muon, and the running of the fine structure constant α to the Z mass scale. They are fundamental ingre...

  10. Vacuum energy as dark matter

    Science.gov (United States)

    Albareti, F. D.; Cembranos, J. A. R.; Maroto, A. L.

    2014-12-01

    We consider the vacuum energy of massive quantum fields in an expanding universe. We define a conserved renormalized energy-momentum tensor by means of a comoving cutoff regularization. Using exact solutions for de Sitter space-time, we show that in a certain range of mass and renormalization scales there is a contribution to the vacuum energy density that scales as nonrelativistic matter and that such a contribution becomes dominant at late times. By means of the WKB approximation, we find that these results can be extended to arbitrary Robertson-Walker geometries. We study the range of parameters in which the vacuum energy density would be compatible with current limits on dark matter abundance. Finally, by calculating the vacuum energy in a perturbed Robertson-Walker background, we obtain the speed of sound of density perturbations and show that the vacuum energy density contrast can grow on sub-Hubble scales as in standard cold dark matter scenarios.

  11. Vacuum energy as dark matter

    CERN Document Server

    Albareti, F D; Maroto, A L

    2014-01-01

    We consider the vacuum energy of massive quantum fields in an expanding universe. We define a conserved renormalized energy-momentum tensor by means of a comoving cutoff regularization. Using exact solutions for de Sitter space-time, we show that in a certain range of mass and renormalization scales there is a contribution to the vacuum energy density that scales as non-relativistic matter and that such a contribution becomes dominant at late times. By means of the WKB approximation, we find that these results can be extended to arbitrary Robertson-Walker geometries. We study the range of parameters in which the vacuum energy density would be compatible with current limits on dark matter abundance. Finally, by calculating the vacuum energy in a perturbed Robertson-Walker background, we obtain the speed of sound of density perturbations and show that the vacuum energy density contrast can grow on sub-Hubble scales as in standard cold dark matter scenarios.

  12. Vacuum Energy and Its Consequences

    Science.gov (United States)

    Hewett, Lionel

    2009-10-01

    Intuitively one would think that a perfect vacuum should contain no energy. However, quantum mechanics asserts that virtual particles popping in and out of existence too fast to be observed directly should produce a non-zero average energy density for empty space. This presentation discusses how quantum mechanics predicts too large a value for this energy density, how the Casimir effect correctly predicts the measured value of the vacuum energy between closely spaced objects, how time-symmetric cosmology predicts the energy density of interstellar space, how vacuum energy produces negative pressure, how vacuum energy causes the current universe to accelerate its expansion, and why vacuum energy cannot be tapped so as to produce an inexhaustible source of energy for all mankind.

  13. The HIE-ISOLDE Vacuum System

    CERN Document Server

    Vandoni, G; Radwan, K; Chiggiato, P

    2014-01-01

    The High Intensity and Energy Isolde (HIE-Isolde) project aims at increasing the energy and intensity of the radioactive ion beams (RIB) delivered by the present Rex-Isolde facility. Energy up to 10MeV/amu will be reached by a new post-accelerating, superconducting (SC) linac. Beam will be delivered via a HEBT to three experimental stations for nuclear physics. To keep the SC linac compact and avoid cold-warm transitions, the cryomodules feature a common beam and insulation vacuum. Radioactive ion beams require a hermetically sealed vacuum, with transfer of the effluents to the nuclear ventilation chimney. Hermetically sealed, dry, gas transfer vacuum pumps are preferred to gas binding pumps, for an optimized management of radioactive contamination risk during maintenance and intervention. The vacuum system of the SC-linac is isolated by two fast valves, triggered by fast reacting cold cathode gauges installed on the warm linac, the HEBT and the experimental stations. Rough pumping is distributed, while the H...

  14. ALICE's first vacuum bakeout a success

    CERN Multimedia

    2007-01-01

    At the beginning of April, the ALICE central beryllium beam pipe and absorber beam pipes were successfully conditioned. The installation and bakeout shell surround the beam pipe (lower left), running through the middle of the ITS and TPC. Notice the high-tech cooling system, an additional precaution to avoid overheating the ALICE detection equipment.One end of the vacuum sector during the bakeout and pure gas refill. It is unusual for a vacuum sector to end as it does in the middle of a non-accessible detector and made the installation and cabling of the bakeout equipment a more difficult procedure. Just before Easter, the first bakeout and NEG activation of experimental chambers in the LHC was carried out, followed by ultra pure gas refill. The bakeout consisted of externally heating the chambers under vacuum in order to lower their outgassing. This same heating process also activates the NEG, a coating on the inside surface of the beam vacuum chambers, which pumps the residual gas. ALICE's bakeout was pa...

  15. True random numbers from amplified quantum vacuum.

    Science.gov (United States)

    Jofre, M; Curty, M; Steinlechner, F; Anzolin, G; Torres, J P; Mitchell, M W; Pruneri, V

    2011-10-10

    Random numbers are essential for applications ranging from secure communications to numerical simulation and quantitative finance. Algorithms can rapidly produce pseudo-random outcomes, series of numbers that mimic most properties of true random numbers while quantum random number generators (QRNGs) exploit intrinsic quantum randomness to produce true random numbers. Single-photon QRNGs are conceptually simple but produce few random bits per detection. In contrast, vacuum fluctuations are a vast resource for QRNGs: they are broad-band and thus can encode many random bits per second. Direct recording of vacuum fluctuations is possible, but requires shot-noise-limited detectors, at the cost of bandwidth. We demonstrate efficient conversion of vacuum fluctuations to true random bits using optical amplification of vacuum and interferometry. Using commercially-available optical components we demonstrate a QRNG at a bit rate of 1.11 Gbps. The proposed scheme has the potential to be extended to 10 Gbps and even up to 100 Gbps by taking advantage of high speed modulation sources and detectors for optical fiber telecommunication devices.

  16. 49 CFR 570.56 - Vacuum brake assist unit and vacuum brake system.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Vacuum brake assist unit and vacuum brake system... Vehicles With GVWR of More Than 10,000 Pounds § 570.56 Vacuum brake assist unit and vacuum brake system. The following requirements apply to vehicles with vacuum brake assist units and vacuum brake systems...

  17. Development of Beryllium Vacuum Chamber Technology for the LHC

    CERN Document Server

    Veness, R; Dorn, C

    2011-01-01

    Beryllium is the material of choice for the beam vacuum chambers around collision points in particle colliders due to a combination of transparency to particles, high specific stiffness and compatibility with ultra-high vacuum. New requirements for these chambers in the LHC experiments have driven the development of new methods for the manufacture of beryllium chambers. This paper reviews the requirements for experimental vacuum chambers. It describes the new beryllium technology adopted for the LHC and experience gained in the manufacture and installation.

  18. High field electron paramagnetic resonance spectroscopy under ultrahigh vacuum conditions—A multipurpose machine to study paramagnetic species on well defined single crystal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Rocker, J.; Cornu, D.; Kieseritzky, E.; Hänsel-Ziegler, W.; Freund, H.-J. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Seiler, A. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Laboratorium für Applikationen der Synchrotronstrahlung, KIT Campus Süd, Kaiserstr. 12, 76131 Karlsruhe (Germany); Bondarchuk, O. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); CIC energiGUNE, Parque Tecnologico, C/Albert Einstein 48, CP 01510 Minano (Alava) (Spain); Risse, T., E-mail: risse@chemie.fu-berlin.de [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin (Germany)

    2014-08-01

    A new ultrahigh vacuum (UHV) electron paramagnetic resonance (EPR) spectrometer operating at 94 GHz to investigate paramagnetic centers on single crystal surfaces is described. It is particularly designed to study paramagnetic centers on well-defined model catalysts using epitaxial thin oxide films grown on metal single crystals. The EPR setup is based on a commercial Bruker E600 spectrometer, which is adapted to ultrahigh vacuum conditions using a home made Fabry Perot resonator. The key idea of the resonator is to use the planar metal single crystal required to grow the single crystalline oxide films as one of the mirrors of the resonator. EPR spectroscopy is solely sensitive to paramagnetic species, which are typically minority species in such a system. Hence, additional experimental characterization tools are required to allow for a comprehensive investigation of the surface. The apparatus includes a preparation chamber hosting equipment, which is required to prepare supported model catalysts. In addition, surface characterization tools such as low energy electron diffraction (LEED)/Auger spectroscopy, temperature programmed desorption (TPD), and infrared reflection absorption spectroscopy (IRAS) are available to characterize the surfaces. A second chamber used to perform EPR spectroscopy at 94 GHz has a room temperature scanning tunneling microscope attached to it, which allows for real space structural characterization. The heart of the UHV adaptation of the EPR experiment is the sealing of the Fabry-Perot resonator against atmosphere. To this end it is possible to use a thin sapphire window glued to the backside of the coupling orifice of the Fabry Perot resonator. With the help of a variety of stabilization measures reducing vibrations as well as thermal drift it is possible to accumulate data for a time span, which is for low temperature measurements only limited by the amount of liquid helium. Test measurements show that the system can detect paramagnetic

  19. Conceptual design and application studies of piezoelectric crystal motors under ultra-high vacuum conditions; Konzepterstellung und Verwendungsmoeglichkeiten eines Piezokristallmotors im Ultrahochvakuum

    Energy Technology Data Exchange (ETDEWEB)

    Nagler, Jens

    2009-08-15

    For the operation of accelerators it is important that motions in the vacuum occur. The here produced diploma thesis deals with the possibility to perform thes motions with piezocrystal motors in order to abandon wear-susceptible membrane bellows. For this studies have been performed, which should show for which it is useful to apply a piezocrystal motor. Limits are shown, advances and disadvantages are weighted in the thesis. Construction with with subsequent test of a tandem facility and an outlook on possible future concepts form the main content. [German] Fuer den Betrieb von Beschleunigern ist es wichtig, dass Bewegungen im Vakuum stattfinden. Die hier angefertigte Diplomarbeit befasst sich mit der Moeglichkeit, diese Bewegungen mit Piezokristallmotoren durchzufuehren, um auf verschleissanfaellige Membranbaelge zu verzichten. Hierfuer sind Studien durchgefuehrt worden, die zeigen sollen, wofuer es ratsam ist, einen Piezokristallmotor zu verwenden. Grenzen werden aufgezeigt, Vor- und Nachteile werden in der Arbeit abgewogen. Konstruktion mit anschliessenden Tests eines Tandemaufbaus und ein Ausblick auf moegliche zukuenftige Konzepte bilden den Kerninhalt. (orig.)

  20. In-service helium leak testing of vacuum furnace

    Science.gov (United States)

    Ahmad, Anis; Tripathi, S. K.; Sawant, P. S.; Mukharjee, D.; Shah, B. K.

    2012-11-01

    Helium leak detection of vacuum furnaces and equipments used for processing of nuclear material is generally carried out by utilizing vacuum spray technique. In this technique helium leak detector is connected to the furnace, back ground reading is noted and helium gas is sprayed on all the suspected joints. Any increase in back ground is noted as leak signal. Processing of Zirconium alloy cladded fuel pins is carried out in vacuum furnace of about 3 meter length and 500 mm inside diameter. Furnace is connected with two numbers of rotary vacuum pump and one number of diffusion pump for creating vacuum (1 × 10-6 torr) inside the furnace. It is desirable that furnace should have good vacuum and best possible leak tightness during dynamic and static vacuum. During dynamic vacuum at higher temperature although required vacuum is achieved the furnace may have fine leakage through which air may enter and cause oxidation of clad tube leading to change in its coloration. This change in coloration will cause rejection of fuel element. Such fine leakages may not be reflected in the dynamic vacuum of the system at high temperature. During trial run change in coloration of outside surface of clad tube was observed although dynamic vacuum of the furnace was in the range of 1×10-6 torr range. To eliminate such possibilities of oxidation due to fine leakages in the system, it was decided to carry out in-service leak testing of the furnace. Helium leak testing of the furnace was carried out by using vacuum spray method and leaks observed were repaired and furnace was retested to ensure the leak tightness. The in-service helium leak testing of the furnace helped in maintaining its leak tightness during service under dynamic vacuum and prevent oxidation of fuel element. This paper describes the techniques of in- service helium leak testing, it's importance for detection of fine leak under dynamic vacuum and discusses details of the testing method and result obtained.