WorldWideScience

Sample records for art high vacuum

  1. Ultra-high vacuum

    CERN Document Server

    Fischer, E

    1974-01-01

    This paper mentions first the requirement of ultra-high vacuum (UHV) for storage rings with colliding beams, and then describes how, in the mid-1950's, the fast development of UHV technology made the construction of the Intersecting Storage Rings (ISR) possible with their 2 km of vacuum pipes at 10/sup -11/ Torr. The performance features are discussed with special emphasis on the problem of stimulated gas desorption from chamber walls. The placing of contracts for sputter-ion pumps and the need for developing sector valves at CERN is mentioned to illustrate that there was some feedback from these constructions to the general development of UHV. Finally, some problems and solutions are listed which are common to other fields where UHV is used: namely in thermonuclear fusion, space research, and manufacturing of integrated circuits.

  2. The fine art of preparing a vacuum

    CERN Multimedia

    2006-01-01

    The vacuum chambers, or beam pipes, of the LHC experiments are located right at the interface between the detectors and the accelerator, and are therefore crucial to the LHC project as a whole. In this domain, the ALICE and CMS experiments have just passed an important milestone, with the completion of the first of CMS's two end-cap vacuum chambers, together with the completion and bakeout of an 18-metre section of the ALICE vacuum chamber. These complex projects, for which CERN's AT/VAC Group is responsible, involved dozens of people over a number of years.

  3. HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM

    International Nuclear Information System (INIS)

    The Department of Energy (DOE) needs improved technologies to decontaminate large areas of both concrete and steel surfaces. The technology should have high operational efficiency, minimize exposures to workers, and produce low levels of secondary waste. In order to meet the DOE's needs, an applied research and development project for the improvement of a current decontamination technology, Vacuum Blasting, is proposed. The objective of this project is to improve the productivity and lower the expense of the existing vacuum blasting technology which has been widely used in DOE sites for removing radioactive contamination, PCBs, and lead-based paint. The proposed work would increase the productivity rate and provide safe and cost-effective decontamination of the DOE sites

  4. Application of high power microwave vacuum electron devices

    International Nuclear Information System (INIS)

    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 gyrotron. 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. (authors)

  5. 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.

  6. High temperature high vacuum creep testing facilities

    International Nuclear Information System (INIS)

    Creep is the term used to describe time-dependent plastic flow of metals under conditions of constant load or stress at constant high temperature. Creep has an important considerations for materials operating under stresses at high temperatures for long time such as cladding materials, pressure vessels, steam turbines, boilers,...etc. These two creep machines measures the creep of materials and alloys at high temperature under high vacuum at constant stress. By the two chart recorders attached to the system one could register time and temperature versus strain during the test . This report consists of three chapters, chapter I is the introduction, chapter II is the technical description of the creep machines while chapter III discuss some experimental data on the creep behaviour. Of helium implanted stainless steel. 13 fig., 3 tab

  7. High vacuum facility for hydrazine thruster testing

    Science.gov (United States)

    Neary, Patrick F.

    1990-01-01

    An ongoing modification is described of a large vacuum chamber to accommodate the ignition of an arcjet hydrazine thruster while maintaining a vacuum level of 1 x 10(exp -5) torr or less. The vacuum facility consists of a 20 ft stainless steel vacuum tank with an internal LN2 shroud, four 35 in. cryopumps and an 8 in. turbopump. To maintain a vacuum level of 1 x 10(exp -5) torr or less, 900 sq ft of liquid helium (LHe) shroud surface was installed to maintain the vacuum level and pumping requirements. A vacuum level of 1 x 10(exp -5) torr or less will allow the hydrazine thrust to exit the thruster nozzle and radiate into a space type environment so that the plume flow field can be analyzed and compared to the analytical model density distribution profile. Some other arcjet thruster characteristics measured are the electromagnetic interference (EMI) and exhaust contamination. This data is used to evaluate if the arcjet thruster with its high specific impulse in comparison to current chemical propulsion thruster can be used for the next generation of communication satellites.

  8. Vacuum requirements in high power microwave tubes

    Energy Technology Data Exchange (ETDEWEB)

    Dammertz, Guenter [Kernforschungszentrum Karlsruhe GmbH (Germany). Inst. fuer Technische Physik

    1995-08-01

    During recent years microwave tubes for low and medium power have been replaced by solid state devices. However, the generation of microwaves at high power is still only possible by the use of high-vacuum electron tubes. For reliable operation and sufficiently long life times severe requirements on vacuum conditions have to be fulfilled. To avoid poisoning of the electron emitter material, high voltage and rf breakdowns, multipactoring and beam instabilities caused by ion oscillations, the pressure in the tubes should not exceed 10{sup -5} Pa. In many cases the tubes are used without any additional pumps or with very small pumps. To preserve the good vacuum conditions over long periods, only very low degassing rates and very low leaking rates (10{sup -12} Pa M{sup 3} s{sup -1}) are required. (author).

  9. High temperature, high vacuum facility for heavy ion simulation studies

    International Nuclear Information System (INIS)

    A high vacuum irradiation facility for heavy ion simulation studies with a tandem accelerator is described. Specimen irradiations are performed at vacuums of less than 10-8 Torr. The samples are heated to temperatures as high as 11000C by a thermal radiation heater. Partial pressure analysis reveals that H2, H2O and CO are the main constituents (approximately 97 percent) of the vacuum. Smaller amounts of CO2, CH4 and C2H4 (approximately 3 percent total) are also present. Beam charge state distribution and beam purity are measured by Rutherford scattering from a gold foil. Beam current densities and profiles are also measured

  10. 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.

  11. Procurement specification high vacuum test chamber and pumping system

    International Nuclear Information System (INIS)

    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

  12. 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.

  13. New small gauge for ultra high vacuum

    International Nuclear Information System (INIS)

    Recently, for large accelerators and storage rings, ultra high vacuum of about 10-11 Torr, and 10-12 Torr for specific cases have been required. In the vacuum measurement for these accelerators, it is estimated that the maintenance of its accuracy is very difficult because of (1) causing error by the incidence of secondary charged particles into vacuum gauges, and (2) the presence of intense noise sources such as electromagnetic interference in the way of output signal transmission and induction by commercial AC power lines. As a solution for (1), the method to prevent the intrusion of charged particles by applying appropriate potential to the double meshes surrounding gauges is considered. However, this method requires to make gauge size small, and necessitates the development of gauges whose K/lambda is larger than 5/Torr-cm, where lambda is the cube root of anode volume in cm, and K is the sensitivity of extractor type ionization gauges in Torr-1. As a solution for (2), the method is considered, in which a modulator electrode is added to a gauge, and an AC amplifier is employed by modulating the ion current. Especially the lock-in detection is effective for improving the S/N ratio. In this paper, the construction and the experimental results of the gauge to which those measures were applied are described. The experimental results include fundamental characteristics, the permeating rate of ions and modulation characteristic. Employing a hemispherical anode in the ion source, the production of the gauges smaller than 1/2 in size as compared with conventional extractor gauges is possible without decreasing the sensitivity. (Wakatsuki, Y.)

  14. High vacuum cells for classical surface techniques

    International Nuclear Information System (INIS)

    Novel glass cells were designed and built to be able to perform surface potential and surface tension measurements in a contained environment. The cells can withstand pressures of approximately 1x10-6 Torr, providing a reasonable level of control in terms of the amounts of volatile contaminants during experimentation. The measurements can take several hours; thus the cells help maintain the integrity of the sample in the course of the experiment. To test for the feasibility of the cell design, calibration measurements were performed. For the surface potential cell, the modified TREK 6000B-7C probe exhibited performance comparable to its unmodified counterpart. The correlation measurements between applied potential on the test surface and the measured potential showed R-values very close to 1 as well as standard deviation values of less than 1. Results also demonstrate improved measurement values for experiments performed in vacuum. The surface tension cell, on the other hand, which was used to perform the pendant drop method, was tested on common liquids and showed percentage errors of 0.5% when compared to literature values. The fabricated cells redefine measurements using classical surface techniques, providing unique and novel methods of sample preparation, premeasurement preparation, and sample analysis at highly beneficial expenditure cost.

  15. 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.

  16. 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.

  17. Performing Arts High Schools: A Burgeoning Movement.

    Science.gov (United States)

    Curtis, Thomas E.

    1987-01-01

    Discusses performing arts high schools that train students in general education and music, visual arts, theater, and dance. Enumerates purposes, advantages (mainly, a challenging and motivating atmosphere with opportunities to concentrate in one area), and problems (funding, understaffing, academic standards, and admission criteria). Advises…

  18. Piezoelectrically Actuated Shutter for High Vacuum

    Science.gov (United States)

    Thompson, Robert; Klose, Gerhard

    2003-01-01

    A piezoelectrically actuated shutter is undergoing development for use in experiments on laser cooling of atoms. The shutter is required to be compatible with ultrahigh vacuum [pressure of 10(exp -9) torr (.1.3 x 10(exp -7) Pa) or less] and to be capable of performing reliably in the vacuum for at least one year. In operation, the shutter would enable the collection and launch of successive samples of cold atoms and would enable the interrogation of the immediately preceding sample while preventing disturbance of the atoms of that sample by light from the collection region. A major constraint is imposed on the design and operation of the shutter by a requirement that it not generate a magnetic field large enough to perturb an atomic clock. An electromagnetically actuated shutter could satisfy all requirements except this one. Hence, it was decided to use piezoelectric instead of electromagnetic actuation. The shutter (see figure) includes two commercial piezoelectrically driven flexure stages that produce a travel of 0.5 mm. Levers mechanically amplify the travel to the required level of 1 cm. Problems that remained to be addressed at the time of reporting the information for this article included lifetime testing and correction of a tendency for shutter blades to bounce open.

  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. 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.

  1. The ultra high vacuum system of the AGS Booster

    Energy Technology Data Exchange (ETDEWEB)

    Hseuh, H.C.; Sadinsky, S.; Savino, J.; Schnitzenbaumer, P.; Sattel, P.; Van Zwienen, W.; Xiuhua, Cui

    1989-01-01

    The AGS Booster currently under construction at Brookhaven is a synchrotron for the acceleration of both protons and heavy ions. The design pressure of 3 /times/ 10/sup /minus/11/ Torr is required to minimize beam loss of the partially stripped heavy ions. This paper described the design and processing of the ultra high vacuum system, and the performance of the prototype vacuum half cells. 9 refs., 4 figs.

  2. A squeezed light source operated under high vacuum

    OpenAIRE

    Wade, Andrew R.; Georgia L. Mansell; Sheon S. Y. Chua; 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 sy...

  3. Large high-vacuum systems for CERN accelerators

    Science.gov (United States)

    Strubin, P.

    2008-05-01

    CERN operated over the more than 50 years of its existence particle accelerators and storage rings ranging from a few tens of metre to 27 km, the size of its latest project, the Large Hadron Collider (LHC) which is under construction and will be started in 2008. The challenges began with the Intersection Storage Rings (ISR) in the seventies. With a beam pipe length of 2 × 1 km, this accelerator required innovative solutions like bake-out and glow discharge to achieve the required static vacuum level, fight against beam-induced pressure increases and cancel beam neutralisation by trapped electrons. The vacuum system of the Large Electron Positron (LEP) storage ring (in operation between 1989 and 2001) of a total length of 27 km had to cope with very high levels of synchrotron power. The beam vacuum system of LHC (2 × 27 km) integrates some parts at 1.9 K and others at room temperature and will also have to cope with dynamic effects. In addition to the beam vacuum system, LHC requires insulation vacuum for the superconducting magnets and the helium distribution line. Whereas the required pressure is not very low, the leak detection and localisation is significantly more demanding for the insulation vacuum than for the beam vacuum because of the large volumes and the thermal insulation. When the size of an accelerator grows, the difficulties are not only to get a clean and leak tight vacuum system, but also to be able to measure reliably pressure or gas composition over long distances. Furthermore, in the case of LHC the integration of the beam vacuum system was particularly difficult because of the complexity induced by a superconducting magnet scheme and the reduced space available for the beam pipes. Planning and logistics aspects during installation, including the usage of mobile pumping and diagnostic means, were much more difficult to manage in LHC than in previous projects.

  4. 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.

  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. Selection and evaluation of an ultra high vacuum gate valve for Isabelle beam line vacuum system

    Energy Technology Data Exchange (ETDEWEB)

    Foerster, C L; McCafferty, D

    1980-01-01

    A minimum of eighty-four (84) Ultra High Vacuum Gate Valves will be utilized in ISABELLE to protect proton beam lines from catastrophic vacuum failure and to provide sector isolation for maintenance requirements. The valve to be selected must function at less than 1 x 10/sup -11/ Torr pressure and be bakeable to 300/sup 0/C in its open or closed position. In the open position, the valve must have an RF shield to make the beam line walls appear continuous. Several proposed designs were built and evaluated. The evaluation consisted mainly of leak testing, life tests, thermal cycling, mass spectrometer analysis, and 10/sup -12/ Torr operation. Problems with initial design and fabrication were resolved. Special requirements for design and construction were developed. This paper describes the tests on two final prototypes which appear to be the best candidates for ISABELLE operation.

  8. 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.

    2015-12-01

    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.

  9. Large high-vacuum systems for CERN accelerators

    CERN Document Server

    Strubin, P

    2008-01-01

    CERN operated over the more than 50 years of its existence particle accelerators and storage rings ranging from a few tens of metre to 27 km, the size of its latest project, the Large Hadron Collider (LHC) which is under construction and will be started in 2008. The challenges began with the Intersection Storage Rings (ISR) in the seventies. With a beam pipe length of 2 × 1 km, this accelerator required innovative solutions like bake-out and glow discharge to achieve the required static vacuum level, fight against beam-induced pressure increases and cancel beam neutralisation by trapped electrons. The vacuum system of the Large Electron Positron (LEP) storage ring (in operation between 1989 and 2001) of a total length of 27 km had to cope with very high levels of synchrotron power. The beam vacuum system of LHC (2 × 27 km) integrates some parts at 1.9 K and others at room temperature and will also have to cope with dynamic effects. In addition to the beam vacuum system, LHC requires insulation vacuum for th...

  10. KIVA reactive hydrodynamics code applied to detonations in high vacuum

    Science.gov (United States)

    Greiner, N. Roy

    1989-08-01

    The KIVA reactive hydrodynamics code was adapted for modeling detonation hydrodynamics in a high vacuum. Adiabatic cooling rapidly freezes detonation reactions as a result of free expansion into the vacuum. After further expansion, a molecular beam of the products is admitted without disturbance into a drift tube, where the products are analyzed with a mass spectrometer. How the model is used for interpretation and design of experiments for detonation chemistry is explained. Modeling of experimental hydrodynamic characterization by laser-schlieren imaging and model-aided mapping that will link chemical composition data to particular volume elements in the explosive charge are also discussed.

  11. Evaluation of ISABELLE full cell ultra high vacuum system

    International Nuclear Information System (INIS)

    The ISABELLE Full Cell Vacuum System consisting of a 40 m long, by 8.8 cm diameter stainless steel tube pumped by seven pumping stations was assembled and processed for 10-12 Torr operation. Evaluation and testing of the system and its sub-assemblies has been completed. Detail design of system components and the determination of the conditioning process was completed. The best procedure to rough pump, leak test, vacuum bake the system, condition pumps, degas gauges, turn on ion pumps and flash sublimation pumps was established. Pressures below 2 x 10-11 Torr are now routinely achieved in normal operation of the Full Cell. This includes pump down after replacement of various components and pump down after back fill with moist unfiltered air. The techniques developed for the Full Cell will be used to build the ISABELLE Ultra High Vacuum System

  12. A highly versatile optical fibre vacuum feed-through

    Science.gov (United States)

    Davidson, Ian A.; Azzouz, Hatim; Hueck, Klaus; Bourennane, Mohamed

    2016-05-01

    Coupling light into a vacuum system is a non-trivial problem, requiring the use of a specialized feed-through. This feed-through must be both leak tight and offer a low optical loss if it is to be suitable for general use. In this paper, we report on the development of an extremely simple yet versatile, low cost, demountable optical fiber vacuum feed-through based on the modification of a standard optical fiber bulkhead connector. The modified connector was found to have a leak rate of 6.6 ± 2.1 × 10-6 mbar l/s and an optical loss of -0.41 ± 0.28 dB, making it suitable for use in high vacuum applications.

  13. 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.

  14. A cryo high-vacuum shuttle for correlative cryogenic investigations

    Czech Academy of Sciences Publication Activity Database

    Tacke, S.; Krzyžánek, Vladislav; Reichelt, R.; Klingauf, J.

    Praha : Czechoslovak Microscopy Society, 2014. ISBN 978-80-260-6720-7. [International Microscopy Congres /18./. Praha (CZ), 07.09.2014-12.09.2014] R&D Projects: GA ČR(CZ) GA14-20012S Institutional support: RVO:68081731 Keywords : cryo-preparation * cryo high-vacuum shuttle * correlative microscopy Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  15. Semipermanent sealing of leaks in high vacuum systems

    Science.gov (United States)

    Christian, J. D.; Gilbreath, W. P.

    1974-01-01

    Silicone-rubber adhesive is applied externally to seal hair-line cracks in sections of high vacuum system while system is partially evacuated. No pretreatment of surface is required since adhesive will be drawn into crack while diffusion or ion pump is off.

  16. Apparatus facilitates high-temperature tensile testing in vacuum

    Science.gov (United States)

    Sikora, P. F.

    1964-01-01

    An apparutus for heating refractory materials to high temperatures during tensile testing includes a water-cooled stainless steel vacuum chamber. This contains a resistance heater consisting of a slit tube of tantalum or tungsten to enclose the tensile test rod.

  17. System for ultra high vacuum made of aluminum alloys

    International Nuclear Information System (INIS)

    We have developed the system for ultra high vacuum made of aluminum alloys for proton and electron synchrotron. This is the first system for ultra high vacuum in which bakable metal seal flange and small diametral bellows of aluminum alloys have been put to practical use. The system consists of the flange protected by a CrN thin film and made of 2219-T87 alloy, the chamber made of 6063-T6 alloy, the aluminum metal gasket of Helico Flex and the bellows made of 5052 alloy. As a result of experiments at the National Laboratory for High Energy Physics (KEK), it had been confirmed that this system shows the special qualities of ultra high vacuum operation, resistance to hard radiation and baking and cooling operations. Up to now, this system has been widely used for the beam lines of the booster synchrotron utilization facility, K1, K2, linac, PI 1 and EP2-B extension of the KEK proton synchrotron. We investigate that this system is applicable to nuclear energy utilization facility and general vacuum apparatus. (author)

  18. Vacuum electronics

    CERN Document Server

    Eichmeier, Joseph A

    2008-01-01

    Nineteen experts from the electronics industry, research institutes and universities have joined forces to prepare this book. ""Vacuum Electronics"" covers the electrophysical fundamentals, the present state of the art and applications, as well as the future prospects of microwave tubes and systems, optoelectronics vacuum devices, electron and ion beam devices, light and X-ray emitters, particle accelerators and vacuum interrupters. These topics are supplemented by useful information about the materials and technologies of vacuum electronics and vacuum technology.

  19. Decay rate of the false vacuum at high tempratures

    International Nuclear Information System (INIS)

    Within the semiclassical approach, the high temperaure behaviour of the decay rate of the metastable vacuum in Field Theory is investigated. It is shown that, contrarily to what has been proposed in the literature, the pre-exponential factor exhibits a nontrivial dependence on the temperature. Furthermore, this dependence is such that at very high temperatures it is as important as the exponential factor and consequently it spoils many conclusions drawn up to now on Cosmological Phase Transitions. (Author)

  20. 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...

  1. New vacuum solar telescope and observations with high resolution

    International Nuclear Information System (INIS)

    The New Vacuum Solar Telescope (NVST) is a one meter vacuum solar telescope that aims to observe fine structures on the Sun. The main goals of NVST are high resolution imaging and spectral observations, including measurements of the solar magnetic field. NVST is the primary ground-based facility used by the Chinese solar research community in this solar cycle. It is located by Fuxian Lake in southwest China, where the seeing is good enough to perform high resolution observations. We first introduce the general conditions at the Fuxian Solar Observatory and the primary science cases of NVST. Then, the basic structures of this telescope and instruments are described in detail. Finally, some typical high resolution data of the solar photosphere and chromosphere are also shown

  2. Vacuum improvements for ultra high charge state ion acceleration

    International Nuclear Information System (INIS)

    The installation of a second cryo panel has significantly improved the vacuum in the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. The neutral pressure in the extraction region decreased from 1.2 x 10-6 down to about 7 x 10-7 Torr. The vacuum improvement reduces beam loss from charge changing collisions and enhances the cyclotron beam transmission, especially for the high charge state heavy ions. Tests with improved vacuum show the cyclotron transmission increased more than 50% (from 5.7% to 9.0%) for a Xe27+ at 603 MeV, more than doubled for a Bi41+ beam (from 1.9% to 4.6%) at 904 MeV and tripled for a U47+ beam (from 1.2% to 3.6%) at 1,115 MeV. At about 5 NeV/nucleon 92 enA (2.2 pnA) for Bi41+ and 14 enA (0.3 pnA) for U47+ were extracted ut of the 88-Inch Cyclotron Ion beams with charge states as high as U64+ have been produced by the LBNL AECR-U ion source and accelerated through the cyclotron for the first time. The beam losses for a variety of ultra high charge state ions were measured as a function of cyclotron pressure and compared with the calculations from the existing models

  3. 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...

  4. Indigenous development of ultra high vacuum (UHV) magnetron sputtering system for the preparation of Permalloy magnetic thin films

    International Nuclear Information System (INIS)

    We have designed and developed an indigenous ultra high vacuum (UHV) sputtering system which can deposit magnetic thin films with high purity and good uniformity. The equipment consists of state-of the-art technologies and sophistication. Turbo-molecular pump combined with sputter ion pump is used to pump down the vacuum chamber up to 10−10 to 10−11 mbar of pressure. With this system it is possible to deposit coatings of various materials on a sample size of diameter 3. The Ni81Fe19 ferromagnetic thin films, with Tantalum (Ta) as a buffer and cap layers have been deposited on silicon substrates using this ultra high vacuum (UHV) sputtering system. The magneto transport measurement study indicated a significant variation in the AMR values of the films for varying thicknesses of tantalum and NiFe layers.

  5. 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

  6. Field installed brazed thermocouple feedthroughs for high vacuum experiments

    Science.gov (United States)

    Anderson, P. M.; Messick, C.

    1983-12-01

    In order to reduce the occurrence of vacuum leaks and to increase the availability of the DIII vacuum vessel for experimental operation, effort was applied to developing a vacuum-tight brazed feedthrough system for sheathed thermocouples, stainless steel sheathed conductor cables and tubes for cooling fluids. This brazed technique is a replacement for elastomer O ring sealed feedthroughs that have proven vulnerable to leaks caused by thermal cycling, etc. To date, about 200 feedthroughs were used. Up to 91 were grouped on a single conflat flange mounted in a bulkhead connector configuration which facilitates installation and removal. Investigation was required to select a suitable braze alloy, flux and installation procedure. Braze alloy selection was challenging since the alloy was required to have: (1) melting temperature in excess of the 250 C (482 F) bakeout temperature; (2) no high vapor pressure elements; (3) good wetting properties when used in air with acceptable flux; and (4) good wettability to 300 series stainless steel and Inconel.

  7. Cooling and stabilization of graphene nanoplatelets in high vacuum

    Science.gov (United States)

    Nagornykh, Pavel

    The study of 2D materials is a rapidly growing area of research, where the ability to isolate and probe an individual single-layer specimen is of high importance. The levitation approach serves as a natural solution for this problem and can be used in ways complementary to the standard techniques. Experiments, including study of properties at high or close to melting temperatures, stretching, folding, vibration and functionalization, can be conducted on levitated 2D materials. As a first step towards realization of all these ideas, one needs to develop and test a system allowing for control over the thermal state and orientation of mono-layer flakes. In this thesis, I present the results of implementation of the parametric feedback cooling scheme in a quadrupole ion trap for stabilization and cooling of graphene nanopletelets. I have tested and showed that the feedback allows to stabilize levitated graphene nanoplatelets in high vacuum conditions (<1 microTorr) to have trapped life times longer than a week. Cooling of the center of mass motion to temperatures below 20 K for all translational degrees of freedom was observed. I have also studied the coupling of DC patch potentials, which were found to be present in the high vacuum chamber. Their effect on cooling was studied and the protocol for minimizing the noise coupling created by the DC fields was designed. We have shown that by varying DC voltages on a set of auxiliary DC electrodes, placed near the trap, one can balance out the DC fields and achieve the lowest cooling temperature. The settings corresponding to this temperature were measured to have a slow drift in time. Ability to tune the settings to balance this drift without breaking the vacuum was studied and found to be a viable solution for the drift cancellation. In addition, our effort in characterization of the flakes is presented. It was shown that the flake discharge quantization observed during the initial pumping down of the high vacuum chamber

  8. Thermal Stabilization in a High Vacuum Cryogenic Optical System

    Science.gov (United States)

    Wallace, Rosa; Cripe, Jonathan; Corbitt, Thomas

    2016-03-01

    The existing technology for gravitational wave detection is limited in part by quantum noise. In our tabletop experiments, we are attempting to lower the noise floor to the quantum limit through the use of a seismically isolated cryogenic high vacuum environment, with the intention of exploring different methods to reduce quantum noise. In the development phase of this environment, we have implemented a customized strategy of ultraviolet irradiation combined with cryogenically cooled radiation shielding to reduce the impact of water vapor and blackbody radiation on the thermal stability of the cryogenic micro-components. Supported by National Science Foundation REU Site #1262890 and CAREER Award #1150531.

  9. High vacuum portable pumping station suitable for accelerator use

    International Nuclear Information System (INIS)

    The need for a Portable Pump Station for Ultra High Vacuum use became apparent when the ''Isabelle'' collider was first being designed. A Portable Pump Station had to be developed which contained the following features: maneuverability, compact size, rugged, self protected against various failures, capable of running unattended, and capable of reaching 10-9 torr. The Pump Station that was developed and other variations are the subject of this paper. Emphasis will be on the Isabelle and HITL versions. 1 ref., 2 figs., 1 tab

  10. Plasma cleaning device. [designed for high vacuum environments

    Science.gov (United States)

    Shannon, R. L.; Gillette, R. B. (Inventor)

    1978-01-01

    High vacuum cleaning of contaminated surfaces such as hydrocarbon containment films can be accomplished by a plasma cleaning device which includes a plasma discharge housing to permit generation of a plasma in an environment having a higher pressure than the surface which is to be cleaned. A ground electrode and a radio frequency electrode partially surround a quartz plasma tube, for the introduction of an ionizable gas. These electrodes ionize the gas and help generate the plasma. This plasma flows through a non-constrictive aperture, through the plasma discharge housing and then on to the contaminated surface.

  11. 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.

  12. 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

  13. Design Status of the ITER Cryostat High Vacuum Pumping System

    International Nuclear Information System (INIS)

    The superconducting magnets and structures of ITER are enveloped by the cryostat vessel which, during normal operation, is evacuated to 0.1 mPa to limit the gas conduction heat load to the cold components to an acceptable level. When the magnets are cold all gases except helium (and to an extent protium) are pumped by the cold magnet surfaces; the former gas arises from leaks in helium bearing pipework inside the cryostat while protium outgases from the warm metallic surfaces facing the cryostat vacuum. Neutron irradiation of epoxy can result in evolution of protium and alkanes. Prior to magnet cool-down, the cryostat has to be pumped down from the crossover pressure of 10 Pa (reached using the mechanical rough pumps) to the nominal operating pressure of 0.1 mPa by the cryostat high vacuum cryopumps. In this operation mode the gas load comprises mainly air and water, the latter outgassing from the ∼ 1300 m2 of vacuum facing epoxy of the poloidal field coils. In order to pump protium and helium at 5 K, the pumping mechanism is cryo-sorption. The sorbent panels have provision for regeneration at three temperature levels, 100 K for helium and protium regeneration, 300 K for regeneration of air-likes and to 475 K for regeneration of water-likes. The last two mentioned have an influence on the sorbent at increasing dose while the amount of helium that can be pumped without regeneration is limited by the sorbent helium capacity. Protium accumulation is limited by the safety requirement to keep the peak regenerated concentration below 1.5 mole/m3, corresponding to a peak deflagration pressure of 0.2 MPa in the event of an air leak into the closed pump prior to or during regeneration. For the cryostat cryopump, adequate total pumping speeds are required for the timely evacuation of water and air during the transient pump-down. Likewise a good helium pumping speed is needed for pumping helium coolant leaks into cryostat vacuum and to obtain an acceptable response time

  14. 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...

  15. 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

  16. Vacuum system design for the PEP-II B Factory High-Energy Ring

    International Nuclear Information System (INIS)

    The design of the vacuum system for the PEP-II B Factory High-Energy Ring is reviewed. The thermal design and vacuum requirements are particularly challenging in PEP-II due to high stored beam currents up to 3.0 amps in 1658 bunches. The vacuum chambers for the HER arcs are fabricated by electron beam welding extruded copper sections up to 6 m long. Design of these chambers and the vacuum PumPing configuration is described with results from vacuum and thermal analyses

  17. Reflections on Teaching and Learning the Arts: A Middle-Grade Classroom and a High School for the Arts

    Science.gov (United States)

    Barilla, Rosemary; Brown, Tina Boyer

    2015-01-01

    Rosemary Barilla, a middle-grade language arts teacher, inspired by her own dedication to the arts, describes the ways she integrates the fine arts into her classroom program that is designed to teach reading and writing. Tina Boyer Brown, a founding teacher at The Chicago High School for the Arts (ChiArts®), describes the school as a place where…

  18. Mechanical design considerations for a precision, ultra high vacuum manipulator

    International Nuclear Information System (INIS)

    The design of mechanisms for use in an ultra high vacuum (UHV) environment presents special problems. The additional design constraints due to requirements of fusion machines further limit the engineer's flexibility in the design process. Requirements for precise control of position and large range of motion present a further challenge. With the advent of tritium in fusion devices, reliability and ease of remote maintenance are matters of paramount importance. The design of the TFTR impurity injector illustrates some of these problems and their solutions. The effects of different impurities on a plasma can be studied by injecting small amounts of an impurity into the plasma and using other diagnostic instruments to record the results. A thin layer of an impurity is coated on a glass slide which is approximately two inches square. A high energy laser beam is focused onto a small spot on the slide. When the laser is pulsed, the impurity evaporates from the target and drifts into the plasma. The TFTR impurity injector will hold sixteen coated slides inside a vacuum. The required positioning accuracy is one tenth of a millimeter. Simultaneous requirements for a large range of motion and high positioning accuracy present unusual design problems. Requirements for radiation resistance and remote maintainability have an impact on the design. In this paper, the trade-offs between different design methodologies are discussed in detail. Various design concepts for the TFTR impurity injector are analyzed from the standpoints of functionality, reliability, and cost; the results are generalized so that they will be of use to other designers

  19. Inductive energy storage using high voltage vacuum circuit breakers

    International Nuclear Information System (INIS)

    Controlled thermonuclear fusion experiments currently being planned require large amounts of pulsed energy. Inductive energy storage systems (IES) appear to be attractive for at least two applications in the fusion research program: high beta devices and those employing turbulent heating. The well-known roadblock to successful implementation of IES is the development of a reliable and cost-effective off-switch capable of handling high currents and withstanding high recovery voltages. The University of Texas at Austin has a program to explore the application of conventional vacuum circuit breakers designed for use in AC systems, in conjunction with appropriate counter pulse circuits, as off-switches in inductive energy storage systems. The present paper describes the IES employing vacuum circuit breakers as off-switches. Since the deionization property of these circuit breakers is of great importance to the design and the cost of the counter-pulse circuit, a synthetic test installation to test these breakers has been conceived, designed and is being installed in the Fusion Research Center, University of Texas at Austin. Some design aspects of the facility will be discussed here. Finally, the results of the study on a mathematical model developed and optimized to determine the least cost system which meets both the requirements of an off-switch for IES Systems and the ratings of circuit breakers used in power systems has been discussed. This analysis indicates that the most important factor with respect to the system cost is the derating of the circuit breakers to obtain satisfactory lifetimes

  20. Fast-action flap valve for high-vacuum or ultrahigh-vacuum operation

    International Nuclear Information System (INIS)

    To prevent the hazardous effects of air ingress into accelerators and into the ultrahigh vacuum of these; a fast-action flap valve for large rated diameters and with a maximum response time of 10 msec has been developed. The valve is characterized by short paths and small amounts of a titanium alloy. (TK)

  1. Ultra high vacuum heating and rotating specimen stage

    Science.gov (United States)

    Coombs, A.W. III

    1995-05-02

    A heating and rotating specimen stage provides for simultaneous specimen heating and rotating. The stage is ideally suited for operation in ultrahigh vacuum (1{times}10{sup {minus}9} torr or less), but is useful at atmosphere and in pressurized systems as well. A specimen is placed on a specimen holder that is attached to a heater that, in turn, is attached to a top housing. The top housing is rotated relative to a bottom housing and electrically connected thereto by electrically conductive brushes. This stage is made of materials that are compatible with UHV, able to withstand high temperatures, possess low outgassing rates, are gall and seize resistant, and are able to carry substantial electrical loading without overheating. 5 figs.

  2. Micro-damage propagation in ultra-high vacuum seals

    International Nuclear Information System (INIS)

    The paper addresses a fundamental problem of tightness of ultra-high vacuum systems (UHV) at cryogenic temperatures in the light of continuum damage mechanics (CDM). The problem of indentation of a rigid punch into an elastic-plastic half-space is investigated based on rate independent plasticity with mixed kinematic and isotropic hardening. The micro-damage fields are modeled by using an anisotropic approach with a kinetic law of damage evolution suitable for ductile materials and cryogenic temperatures. The model has been experimentally validated and the results are used to predict the onset of macro-cracking (loss of tightness) and the corresponding load (contact pressure). The algorithm is applied in the design of UHV systems for particle accelerators.

  3. Micro-damage propagation in ultra-high vacuum seals

    CERN Document Server

    Lutkiewicz, P; Garion, C

    2010-01-01

    The paper addresses a fundamental problem of tightness of ultra-high vacuum systems (UHV) at cryogenic temperatures in the light of continuum damage mechanics (CDM). The problem of indentation of a rigid punch into an elastic-plastic half-space is investigated based on rate independent plasticity with mixed kinematic and isotropic hardening. The micro-damage fields are modeled by using an anisotropic approach with a kinetic law of damage evolution suitable for ductile materials and cryogenic temperatures. The model has been experimentally validated and the results are used to predict the onset of macro-cracking (loss of tightness) and the corresponding load (contact pressure). The algorithm is applied in the design of UHV systems for particle accelerators. (C) 2009 Published by Elsevier Ltd.

  4. Prediction of the quality of coke obtained from vacuum residues by using spectroscopy infrared FTIR-ART

    Science.gov (United States)

    León, A. Y.; Rodríguez, N. A.; Mejía, E.; Cabanzo, R.

    2016-02-01

    According to the trend of the heavy crudes and high demand of fuels, it is projected a considerable increase in the production of vacuum residues. With the purpose of taking advantage of these loads, the refineries have been improving conversion processes for the production of better quality distillates. However, as increasing the severity conditions and the species content of resins and asphaltenes high concentrations of coke are obtained. To provide an insight into the quality and cokes properties, in this study fifty (50) coke samples obtained from vacuum residues processed under conditions of thermal cracking and hydroconversion were selected. Each coke was analysed in detail with properties such as fixed carbon, volatile material, ash, and calorific value. Subsequently, a characterization methodology was developed to predict the properties of cokes, by using partial least squares regression, and infrared spectroscopy (FTIR-ATR) in the spectral range from 4000 to 500cm-1. The models obtained by chemometrics allowed to predict the quality of the coke produced from vacuum residues with reliable responses in short periods of time.

  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. 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.

  7. High Quality Art Education: For Inclusion and Resilience

    OpenAIRE

    Stewart, Rachel Dawn

    2011-01-01

    Increasingly, general education teachers must incorporate special education learners into the mainstream learning classroom. This thesis summarizes the way in which integrating a high-quality education in the arts (dance, music, theatre, visual arts) can support the alternative learner and enhance the educational experience in the general education classroom. By creating a multi-modal learning environment and supporting general studies with arts-based therapies, least restrictive and cultur...

  8. 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.

  9. High-current picosecond electron source with a high-impedance vacuum diode

    International Nuclear Information System (INIS)

    The picosecond (∼ 190 ps) high-current channel of direct-action electron accelerator with the beam energy of approximately 1.2 MeV by the current of about 0.4 kA is described. Three-stage line and vacuum diode, the impedance whereof is essentially higher than the line wave resistance, are used for formation of high accelerating voltage. The method for calculating the accelerating voltage, beam current, vacuum diode impedance and other parameters by measured incident and reflection pulses, extending in the line, is considered

  10. Vacuum disc: frequency of high signal intensity on T2-weighted MR images

    International Nuclear Information System (INIS)

    Objective. To determine the frequency of lumbar intervertebral disc vacuum clefts demonstrating high signal intensity on T2-weighted magnetic resonance (MR) images. Design and patients. MR images of the lumbosacral spine of 100 patients with radiographic evidence of the lumbar intervertebral disc vacuum phenomenon were retrospectively studied for the signal pattern of the intervertebral disc vacuum clefts. Results and conclusion. Twelve of the reviewed MR studies demonstrated high signal intensity of the vacuum clefts on long TR and TE sequences while the remaining 88 cases demonstrated the vacuum as signal void on both T1- and T2-weighted images. It is concluded that vacuum clefts not infrequently show high T2 signal intensity. (orig.)

  11. Vacuum birefringence in high-energy laser-electron collisions

    CERN Document Server

    King, B

    2016-01-01

    Real photon-photon scattering is a long-predicted phenomenon that is being searched for in experiment in the form of a birefringent vacuum at optical and X-ray frequencies. We present results of calculations and numerical simulations for a scenario to measure this effect using multi-MeV photons generated in the collision of electrons with a laser pulse. We find that the birefringence of the vacuum should be measurable using experimental parameters attainable in the near future.

  12. Artfulness

    DEFF Research Database (Denmark)

    Chemi, Tatiana

    2011-01-01

    a collage of previously published materials on Artfulness, in this journal targeted teachers for dysfunctional behaviour children.......a collage of previously published materials on Artfulness, in this journal targeted teachers for dysfunctional behaviour children....

  13. Cavity cooling of free silicon nanoparticles in high-vacuum

    CERN Document Server

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

    2013-01-01

    Laser cooling has given a boost to atomic physics throughout the last thirty years since it allows one to prepare atoms in motional states which can only be described by quantum mechanics. Most methods, such as Doppler cooling, polarization gradient cooling or sub-recoil laser cooling rely, however, on a near-resonant and cyclic coupling between laser light and well-defined internal states. Although this feat has recently even been achieved for diatomic molecules, it is very hard for mesoscopic particles. It has been proposed that an external cavity may compensate for the lack of internal cycling transitions in dielectric objects and it may thus provide assistance in the cooling of their centre of mass state. Here, we demonstrate cavity cooling of the transverse kinetic energy of silicon nanoparticles propagating in genuine high-vacuum (< 10^8 mbar). We create and launch them with longitudinal velocities even down to v < 1 m/s using laser induced thermomechanical stress on a pristine silicon wafer. The ...

  14. Design and performance of vacuum system for high heat flux test facility

    International Nuclear Information System (INIS)

    High heat flux test facility (HHFTF) at IPR is used for testing thermal performance of plasma facing material or components. It consists of various subsystems like vacuum system, high power electron beam system, diagnostic and calibration system, data acquisition and control system and high pressure high temperature water circulation system. Vacuum system consists of large D-shaped chamber, target handling system, pumping systems and support structure. The net volume of vacuum chamber is 5m3 was maintained at the base pressure of the order of 10-6 mbar for operation of electron gun with minimum beam diameter. Inorder to achieve the ultimate vacuum, turbo-molecular pump (TMP) and cryo pump are installed. Each TMP and cryo-pump unit has an electro-pneumatic gate valve of respective size to isolate the pump in the case of either vacuum break in the D-shaped chamber or in case of the pump failure to protect each in either condition. A variable conductance gate valve is used for maintaining required vacuum in the chamber. Initial pumping of the chamber was carried out by using suitable rotary and root pumps. PXI and PLC based faster real time data acquisition and control system is implemented for performing the various operations like remote operation, online vacuum data measurements, display and status indication of all vacuum equipments. This paper describes in detail the design and implementation of various vacuum subsystems including relevant experimental details. (author)

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

    International Nuclear Information System (INIS)

    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

  16. Stable Field Emission from Layered MoS2 Nanosheets in High Vacuum and Observation of 1/f Noise

    OpenAIRE

    Ranjit V. Kashid; Joag, Pracheetee D.; Thripuranthaka, M.; Rout, Chandra S.; Late, Dattatray J.; More, Mahendra A.

    2015-01-01

    Field emission and current noise of hydrothermally synthesized MoS2 nanosheets are investigated in ultra- high-vacuum and industrially suited high-vacuum conditions. The study reveals that the emission turn-on field is pressure dependent. Moreover, the MoS2 nano‐ sheets exhibit more stable field-electron emission in high- vacuum than in ultra-high-vacuum conditions. The investigations on field-emission current fluctuations show features of 1/f-type noise in ultra-high-vacuum and high- vacuum ...

  17. High Reliability R-10 Windows Using Vacuum Insulating Glass Units

    Energy Technology Data Exchange (ETDEWEB)

    Stark, David

    2012-08-16

    The objective of this effort was for EverSealed Windows (“EverSealed” or “ESW”) to design, assemble, thermally and environmentally test and demonstrate a Vacuum Insulating Glass Unit (“VIGU” or “VIG”) that would enable a whole window to meet or exceed the an R-10 insulating value (U-factor ≤ 0.1). To produce a VIGU that could withstand any North American environment, ESW believed it needed to design, produce and use a flexible edge seal system. This is because a rigid edge seal, used by all other know VIG producers and developers, limits the size and/or thermal environment of the VIG to where the unit is not practical for typical IG sizes and cannot withstand severe outdoor environments. The rigid-sealed VIG’s use would be limited to mild climates where it would not have a reasonable economic payback when compared to traditional double-pane or triple-pane IGs. ESW’s goals, in addition to achieving a sufficiently high R-value to enable a whole window to achieve R-10, included creating a VIG design that could be produced for a cost equal to or lower than a traditional triple-pane IG (low-e, argon filled). ESW achieved these goals. EverSealed produced, tested and demonstrated a flexible edge-seal VIG that had an R-13 insulating value and the edge-seal system durability to operate reliably for at least 40 years in the harshest climates of North America.

  18. Art

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    What is Art?Art is a way of interpreting the worldaround us and our place within it.We can seeart not only in paintings,but in sculpture(雕塑),buildings and even advertising.Traditionally(传统上,照惯例),artists werejudged more for their technical skill,but artnowhas an aesthetic(美学的,审美的)valueand/or emotional impact(冲动).Art doesn't

  19. 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.

  20. The latest vacuum detectors for high energy physics

    International Nuclear Information System (INIS)

    In recent energy physics experiments, many environmental conditions have changed in comparison with past experiments, mainly because of the higher energies, luminosities and measuring accuracy. Hamamatsu is continuously developing new types of detectors to keep up with this trend. The performance and expected applications of the latest vacuum detectors are discussed in this paper. (orig.)

  1. Adaptive reduction of the vibrations from a vacuum pump for high-precision equipment

    NARCIS (Netherlands)

    Berkhoff, A.P.; Wesselink, J.M.; Basten, T.G.H.

    2008-01-01

    This paper describes experiments with active vibration reduction on a setup with a vacuum pump that is tightly coupled with high-precision equipment. The precision of this equipment is critically dependent on the level of the vibrations that are introduced by the vacuum pump. The vibrations were red

  2. The development of ultrahigh and extreme high vacuum technology for physics research

    CERN Document Server

    Dylla, H F

    2007-01-01

    Over the last 50 years increasingly larger and more sophisticated devices have been designed and put into operation for the study of particle and nuclear physics, magnetic confinement of high-temperature plasmas for thermonuclear fusion research, and gravity wave observatories based on laser interferometers. The evolution of these devices has generated many developments in ultrahigh and extreme high vacuum technology that were required for these devices to meet their operational goals. The technologies that were developed included unique ultrahigh vacuum vessel structures, ultrahigh vacuum compatible materials, surface conditioning techniques, specialized vacuum pumps and vacuum diagnostics. Associated with these technological developments are scientific advancements in the understanding of outgassing limits of UHV-compatible materials and particle-induced desorption effects.

  3. A simple, high-yield, apparatus for NEG coating of vacuum beamline elements

    International Nuclear Information System (INIS)

    Non-Evaporable Getter (NEG) materials are extremely useful in vacuum systems for achieving Ultra High Vacuum. Recently, these materials have been used to coat the inner surfaces of vacuum components, acting as an internal, passive, vacuum pump. We have constructed a low cost apparatus, which allows coating of very small diameter vacuum tubes, used as differential pumping stages. Despite the relative ease of construction, we are routinely able to achieve high coating yields. We further describe an improvement to our system, which is able to achieve the same yield, at an even lower complexity by using an easily manufactured permanent magnet arrangement. The designs described are extendible to virtually any combination of length and diameter of the components to be coated.

  4. Ultra high vacuum system for Isabelle full cell

    International Nuclear Information System (INIS)

    A vacuum system consisting of a 40 m long 8.8 cm diameter stainless steel tube, pumped by 7 pumping stations, has been assembled using automatic welding methods. All components have been fired at 9500C in a vacuum furnace at a pressure -4 Torr. Each pumping station contains a Ti-sublimator, a 30 liter/s ion pump and an UHV gauge. After assembly, the entire system was baked out at 2500C for 24 hours. A pressure -11 Torr was reached after titanium flash. Surface treatment of stainless for 10-11 Torr operation, bake out and conditioning cycle to read 1 x 10-11 Torr, and leak checking at low pressures are discussed

  5. High separative power vacuum arc centrifuge (HSP-VAC)

    International Nuclear Information System (INIS)

    The reliability of supply of stable isotopes needed in medicine and science has been a problem for decades. Among the many sources of enriched stable isotopes are the Calutrons at Oak Ridge National Laboratory, ICONS of Cambridge Isotopes Limited, and reactors such as at Atomic Energy of Canada Ltd. and elsewhere. Alameda Applied Sciences Corporation (AASC) staff have spearheaded the development of a new type of isotope separator, dubbed the Vacuum Arc Centrifuge (VAC). This effort dates to the 1980s under National Science Foundation sponsorship at Yale, the early 1990s under a U.S. Department of Energy grant, and more recently, under AASC internal funding. The VAC consists of a vacuum arc discharge between a metal cathode (containing the substances to be separated) and a mesh anode across a small gap

  6. Vacuum Shear Force Microscopy Application to High Resolution Work

    Science.gov (United States)

    Polonski, Vitali; Yamamoto, Yoh; White, Jonathon; Kourogi, Motonobu; Ohtsu, Motoichi

    1999-07-01

    A new technique—Vacuum Shear Force Microscopy (VSFM)—is introduced as a reliable method for maintaining a constant separation between a probe and sample. Elimination of many of the instabilities observed when applying the shear force mechanism to imaging under ambient conditions, allows for routine nanometer lateral and sub-nanometer normal resolution. In this paper this technique is applied, firstly, to the imaging of microtubules (biology) and, secondly, to the patterning and subsequent imaging of nanoscale metal lines (nanofabrication).

  7. ARTS

    DEFF Research Database (Denmark)

    Mahadevan, Shankar; Virk, Kashif M.; Madsen, Jan

    2007-01-01

    . We present an abstract system-level modelling and simulation framework (ARTS) which allows for cross-layer modelling and analysis covering the application layer, middleware layer, and hardware layer. ARTS allows MPSoC designers to explore and analyze the network performance under different traffic...... and load conditions, consequences of different task mappings to processors (software or hardware) including memory and power usage, and effects of RTOS selection, including scheduling, synchronization and resource allocation policies. We present the application and platform models of ARTS as well as...... their implementation in SystemC. We present the usage of the ARTS framework as seen from platform developers’ point of view, where new components may be created and integrated into the framework, and from application designers’ point of view, where existing components are used to explore possible...

  8. Detecting vacuum birefringence with x-ray free electron lasers and high-power optical lasers: a feasibility study

    Science.gov (United States)

    Schlenvoigt, Hans-Peter; Heinzl, Tom; Schramm, Ulrich; Cowan, Thomas E.; Sauerbrey, Roland

    2016-02-01

    We study the feasibility of measuring vacuum birefringence by probing the focus of a high-intensity optical laser with an x-ray free electron laser (XFEL). This amounts to performing a new type of QED precision experiment, employing only laser pulses, hence space- and time-dependent fields. To set the stage, we briefly review the status of QED precision tests and then focus on the example of vacuum birefringence. Adopting a realistic laser beam model in terms of pulsed Gaussian beams we calculate the induced phase shift and translate it into an experimental signal, counting the number of photons with flipped polarization. We carefully design a detailed experiment at the European XFEL operating in self-seeded mode, supplemented by a petawatt class optical laser via the HIBEF project. Assuming all components to represent the current state of the art, in particular the x-ray polarizers, realistic estimates of signal-to-noise ratios plus ensuing acquisition times are provided. This is accompanied by a statistical analysis of the impact of poor laser focus overlap either due to timing and pointing jitter as well as limited alignment accuracy. A number of parasitic effects are analyzed together with appropriate countermeasures. We conclude that vacuum birefringence can indeed be measured upon combining an XFEL with a high-power optical laser if depolarization effects in the x-ray lenses can be controlled.

  9. 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.

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

    International Nuclear Information System (INIS)

    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

  11. 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...

  12. 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...

  13. 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.

  14. Cermet insert high voltage holdoff improvement for ceramic/metal vacuum devices

    Science.gov (United States)

    Ierna, W.F.

    1986-03-11

    An improved metal-to-ceramic seal is provided wherein the ceramic body of the seal contains an integral region of cermet material in electrical contact with the metallic member, e.g., an electrode, of the seal. The seal is useful in high voltage vacuum devices, e.g., vacuum switches, and increases the high-voltage holdoff capabilities of such devices. A method of fabricating such seals is also provided.

  15. Cermet insert high voltage holdoff for ceramic/metal vacuum devices

    Science.gov (United States)

    Ierna, William F.

    1987-01-01

    An improved metal-to-ceramic seal is provided wherein the ceramic body of the seal contains an integral region of cermet material in electrical contact with the metallic member, e.g., an electrode, of the seal. The seal is useful in high voltage vacuum devices, e.g., vacuum switches, and increases the high-voltage holdoff capabilities of such devices. A method of fabricating such seals is also provided.

  16. Examination of Taiwan’s Contemporary Art: Discourse Analysis of Contemporary Art in Taiwan in High School Textbooks

    OpenAIRE

    Tian-An Chuu

    2009-01-01

    This article selects two editions of a high school textbook with chapters on contemporary art in Taiwan. We borrow the language use and social production of discourse analysis to analyze the text of the two editions.From the above discourse analysis, it is possible to summarize the present status of contemporary art in Taiwan as it is presented in high school textbooks. It is as follows: (1) contemporary art represents the development of art in a certain period of time in the history of art i...

  17. Practical of Ethics Education in Junior High School Technical Arts

    Science.gov (United States)

    Iwata, Ryo; Hirano, Shigeo

    Now, such as forgery, camouflage, concealment, and the alteration, the problems resulting from lack of the sense of ethics are occurring frequently. The department of junior high school technical arts to engineering ethics education is required for the solution. However, the example of introducing the ethics education is few in a current junior high school technical arts department. It is considered that it leads to a further improvement of the morality consideration by teaching from a past case to the engineering ethics at the stage of the compulsory education. In this thesis, it reports on the execution contents and an educational result.

  18. Managing Coil Epoxy Vacuum Impregnation Systems at the Manufacturing Floor Level To Achieve Ultimate Properties in State-of-the-Art Magnet Assemblies

    CERN Document Server

    Hubrig, Jeffrey G

    2005-01-01

    Liquid epoxy resin impregnation systems remain a state-of-the-art polymer material for vacuum and vacuum/pressure impregnation applications in the manufacture of both advanced and conventional coil winding configurations. Epoxy resins inherent latitude in processing parameters accounts for their continued popularity in engineering applications, but also for the tendency to overlook or misinterpret the requisite processing parameters on the manufacturing floor. Resin system impregnation must be managed in detail in order to achieve device life cycle reliability. This closer look reveals how manufacturing floor level management of material acceptance, handling and storage, pre- and post- impregnation processing and cure can be built into a manufacturing plan to increase manufacturing yield, lower unit cost and ensure optimum life cycle performance of the coil.

  19. Managing Coil Epoxy Vacuum Impregnation Systems at the Manufacturing Floor Level To Achieve Ultimate Properties in State-of-the-Art Magnet Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    J.G. Hubrig; G.H. Biallas

    2005-05-01

    Liquid epoxy resin impregnation systems remain a state-of-the-art polymer material for vacuum and vacuum/pressure impregnation applications in the manufacture of both advanced and conventional coil winding configurations. Epoxy resins inherent latitude in processing parameters accounts for their continued popularity in engineering applications, but also for the tendency to overlook or misinterpret the requisite processing parameters on the manufacturing floor. Resin system impregnation must be managed in detail in order to achieve device life cycle reliability. This closer look reveals how manufacturing floor level management of material acceptance, handling and storage, pre- and post- impregnation processing and cure can be built into a manufacturing plan to increase manufacturing yield, lower unit cost and ensure optimum life cycle performance of the coil.

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2008-05-01

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

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

    CERN Document Server

    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.

  3. 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.

  4. 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.

  5. Vacuum deposition of high quality metal films on porous substrates

    International Nuclear Information System (INIS)

    A composite mandrel has been developed consisting of a core of low density polymethylpentene foam overcoated with a thin layer of film-forming polymer. The surface tension and viscosity of the coating solution are important parameters in obtaining a polymer film which forms a continuous, smooth skin over the core without penetrating into the foam matrix. Water soluble film formers with surface tensions in the range of 45 dyn/cm and minimum viscosities of a few hundred centipoises have been found most satisfactory for coating polymethylpentene foam. By means of this technique, continuous polymer fims with thicknesses of 10--20 μm have been formed on the surface of machined polymethylpentene foam blanks. Aluminum has been vacuum deposited onto these composite mandrels to produce metal films which appear smooth and generally defect free even at 10 000 times magnification

  6. Development of High vacuum facility for baking and cool down experiments for SST-1 Tokamak components

    International Nuclear Information System (INIS)

    SST-1 Tokamak, a steady state super-conducting device, is under refurbishment to demonstrate the plasma discharge for the duration of 1000 second. The major fabricated components of SST-1 like vacuum vessel, thermal shields, superconducting magnets etc have to be tested for their functional parameters. During machine operation, vacuum vessel will be baked at 150 °C, thermal shields will be operated at 85 K and magnet system will be operated at 4.5 K. All these components must have helium leak tightness under these conditions so far as the machine operation is concerned. In order to validate the helium leak tightness of these components, in-house high vacuum chamber is fabricated. This paper describes the analysis, design and fabrication of high vacuum chamber to demonstrate these functionalities. Also some results will be presented.

  7. Stable Field Emission from Layered MoS2 Nanosheets in High Vacuum and Observation of 1/f Noise

    Directory of Open Access Journals (Sweden)

    Ranjit V. Kashid

    2015-04-01

    Full Text Available Field emission and current noise of hydrothermally synthesized MoS2 nanosheets are investigated in ultra- high-vacuum and industrially suited high-vacuum conditions. The study reveals that the emission turn-on field is pressure dependent. Moreover, the MoS2 nano‐ sheets exhibit more stable field-electron emission in high- vacuum than in ultra-high-vacuum conditions. The investigations on field-emission current fluctuations show features of 1/f-type noise in ultra-high-vacuum and high- vacuum conditions, attributed to adsorption and desorp‐ tion processes. The post-field-emission results indicate the MoS2 nanosheets are a robust field emitter in high- vacuum conditions.

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

    OpenAIRE

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

    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...

  9. Observation of Live Ticks (Haemaphysalis flava) by Scanning Electron Microscopy under High Vacuum Pressure

    OpenAIRE

    ISHIGAKI, YASUHITO; Nakamura, Yuka; Oikawa, Yosaburo; Yano, Yasuhiro; Kuwabata, Susumu; Nakagawa, Hideaki; Tomosugi, Naohisa; Takegami, Tsutomu

    2012-01-01

    Scanning electron microscopes (SEM), which image sample surfaces by scanning with an electron beam, are widely used for steric observations of resting samples in basic and applied biology. Various conventional methods exist for SEM sample preparation. However, conventional SEM is not a good tool to observe living organisms because of the associated exposure to high vacuum pressure and electron beam radiation. Here we attempted SEM observations of live ticks. During 1.5×10−3 Pa vacuum pressure...

  10. 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.

  11. Alchemy in Iowa: Arts Education at Harding Junior High School.

    Science.gov (United States)

    Vallance, Elizabeth

    1991-01-01

    Case study of an Iowa junior high school describes how the school and community identified their resources and used them to create successful arts education programs from ordinary resources. The article examines four types of commitment that shaped school practice, noting effective teaching practices and administrative policy. (SM)

  12. An assessment of the hardness of miniature vacuum tubes to high-voltage transients

    Energy Technology Data Exchange (ETDEWEB)

    Orvis, W.J.

    1990-03-01

    Miniature vacuum tubes are vacuum switching and control devices fabricated on a silicon wafer, using the same technology as is used to make integrated circuits. They operate in much the same manner as conventional vacuum tubes, but with two important differences: they are micron sized devices, and they employ field emission instead of thermionic emission as the electron source. As these devices have a vacuum as their active region, they will be extremely hard to nuclear radiation and relatively insensitive to temperature effects, they are also expected to be extremely fast devices. We have estimated here that their hardness to high-voltage transients will be at least as good as existing semiconductor devices and possibly better. 5 figs.

  13. An assessment of the hardness of miniature vacuum tubes to high-voltage transients

    Science.gov (United States)

    Orvis, William J.

    1990-03-01

    Miniature vacuum tubes are vacuum switching and control devices fabricated on a silicon wafer, using the same technology as is used to make integrated circuits. They operate in much the same manner as conventional vacuum tubes, but with two important differences: they are micron sized devices, and they employ field emission instead of thermionic emission as the electron source. As these devices have a vacuum as their active region, they will be extremely hard to nuclear radiation and relatively insensitive to temperature effects, they are also expected to be extremely fast devices. We have estimated here that their hardness to high-voltage transients will be at least as good as existing semiconductor devices and possibly better.

  14. Construction and commissioning of the AGS Booster ultra-high vacuum system

    International Nuclear Information System (INIS)

    The recently completed AGS Booster is a synchrotron for the acceleration of both protons and heavy ions. To minimize the beam loss due to charge exchange of the partially stripped, low β (= v/c), very heavy ions with the residual gas molecules, ultra high vacuum of 10-11 Torr is required for the 200 m Booster ring. An average pressure of mid 10-11 Torr has been achieved and maintained after initial insitu bakes and commissioning. In this paper we describe: (1) design and layout of the vacuum systems; (2) material selection and vacuum processing; (3) PC/PLC based bakeout system; (4) operation of vacuum instrumentation over long cable length; (5) results of bakeout and evaluation; and (6) experience gained during construction and commissioning

  15. Design and fabrication of hotbox of high temperature vacuum degassing furnace

    International Nuclear Information System (INIS)

    A storage ring of Indus-I and Indus-II SRS made of several components has been developed at Centre for Advanced Technology, Indore. These components are made ultra high vacuum (UHV) compatible by way of vacuum degassing at elevated temperature under high vacuum environment by using vacuum degassing facility available at the centre. The furnace was designed for hotbox size of 700mm x 700mm x 800mm. The vacuum degassing has been carried out at a temperature of 800 deg C and at an operating vacuum of 5 x 10-6 Torr. The above facility is in continuous use since 1992. The core part of the furnace is the hotbox. It consists of heating elements, radiation shields etc. Failure of heating element due to distortion is a major problem. It is because of repeated heating and cooling cycles of the furnace. A hotbox has been designed and fabricated keeping in view the above problem of distortion of the heating elements. Necessary corrections and modifications have been done in the conventional design of the hotbox. Frequent failures of heating elements have come down to the minimum. Down time of the system is reduced and there is drastic improvement in performance of the facility. This paper discusses suitable techniques and methods adopted for fabrication of the hotbox and its components. (author)

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

    Science.gov (United States)

    Schwindt, Peter D. D.; Jau, Yuan-Yu; Partner, Heather; Casias, Adrian; Wagner, Adrian R.; Moorman, Matthew; Manginell, Ronald P.; Kellogg, James R.; Prestage, John D.

    2016-05-01

    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 cm3 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 171Y b+. The fractional frequency stability of the clock was measured to be 2 × 10-11/τ1/2.

  17. An ultra-high vacuum chamber for scattering experiments featuring in-vacuum continuous in-plane variation of the angle between entrance and exit vacuum ports

    International Nuclear Information System (INIS)

    A concept that enables in-vacuum continuous variation of the angle between two ports in one plane has been developed and implemented. The vacuum chamber allows for measuring scattering cross sections as a function of scattering angle and is intended for resonant inelastic X-ray scattering experiments. The angle between the ports can be varied in the range of 30°-150°, while the pressure change is less than 2 × 10−10 mbars

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

    International Nuclear Information System (INIS)

    Electron beam (EB) welding in UHV (ultra-high vacuum, 10-5 divide 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 divide 3 wt. ppm hydrogen and 5 divide 7 ppm oxygen and nitrogen), essential for high values of RRR - 350 divide 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

  19. Note: Simple leak sealing technique for ultra-high vacuum cryostat by using freezable liquid.

    Science.gov (United States)

    Kim, Min-Seong; Kim, Ji-Ho; Lyo, In-Whan

    2015-05-01

    Here we introduce a simple, low-cost, contamination-free, and highly reliable technique for sealing an ultra-high vacuum (UHV) cryostat by using cryogenically freezable liquid. We demonstrate it by sealing an UHV cryostat with dry leaks in the high vacuum range; ethanol was utilized to fill and block the leakage pathways through the subsequent in situ solidification by LN2. The seal is reversible and can be maintained as long as the cryostat is kept at cryogenic temperature. PMID:26026566

  20. Interaction of organic surfaces with active species in the high-vacuum environment

    Science.gov (United States)

    Podzorov, V.; Menard, E.; Pereversev, S.; Yakshinsky, B.; Madey, T.; Rogers, J. A.; Gershenson, M. E.

    2005-08-01

    Using single-crystal organic field-effect transistors with the conduction channel exposed to environmental agents, we have observed generation of electronic defects at the organic surface in the high-vacuum environment. Rapid decrease of the source-drain current of an operating device is observed upon exposure of the channel to the species generated by high-vacuum gauges. We attribute this effect to interaction of the organic surface with electrically neutral free radicals produced in the process of hydrocarbon cracking on hot filaments with a relatively low activation energy Ea˜2.5eV (240kJ/mol). The reported results might be important for optimizing the high-vacuum processes of fabrication and characterization of a wide range of organic and molecular electronic devices.

  1. RF high voltage test and thermal analysis on the ICRF vacuum feed-through

    International Nuclear Information System (INIS)

    The KSTAR Ion Cyclotron Range of Frequency (ICRF) system has been developed for high-power, long-pulse plasma heating at frequencies from 25 to 60 MHz. KSTAR achieved the first high-performance confinement fusion plasmas in the 2010 experimental campaign, which is an important milestone for the reactor-relevant research of steady-state, high performance fusion plasma in the superconducting tokamak. The feed-through has to withstand high RF voltage or large RF current, while keeping the antenna in high vacuum. In order to study RF voltage and thermal characteristics in the VFT, we have fabricated and tested a new feed-through in the vacuum chamber with a high voltage/current RF test stand. We have fabricated and tested a vacuum feed through to investigate the RF high voltage and thermal characteristics of the KSTAR ICRF system for high power and long pulse operation. In comparison with the temperature measurement of VFT at the RF high voltage test, we found ANSYS thermal analysis helps us to resolve the temperature distributions in complex geometry such as the vacuum feed-through

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

    International Nuclear Information System (INIS)

    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.

  3. 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.

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

    OpenAIRE

    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 gratings with up to 10,000 lines per mm and various space-to-period ratios were fabricated. An optical characterization of the gratings was carried out in the range from 17 to 34 nm wavelength using high...

  5. Study on condensation-sorption forevacuum and high-vacuum traps

    International Nuclear Information System (INIS)

    Condensation-sorption forevacuum and high-vacuum traps and the results of tests of their performances are described. These traps are designed for preventing the vapor of working liquids of vacuum pumps from penetrating to the pumped-out volumes. The DU-25 nitrogen forevacuum trap has been tested at vacuum of (10-4-10-5) torr. The efficiency of the DU-25 heated condensation-sorption trap has been studied combining it with the oil-diffusion forevacuum, oil-diffusion, turbomolecular pumps. The conclusions are as follows: the DU-63 trap can be recommended as a simple, reliable and effective shielding of pumped-out volumes from penetration of the oil vapors from forevacuum mechanical pumps; the DU-63 trap is an economical, universal and high efficiency shielding preventing the penetration of the vapor of working liquids to pumped-out volumes in the range from 10-3 to 10-10 torr. It can be used as an autonomous pump, which enables to achieve the vacuum up to 10-10 torr. The DU-63 trap can successfully be used for pumping-out an extended vacuum tubes of physical devices and instruments, particle accelerators, in particular

  6. Art Animates: Ideas Inspired by a University-Sponsored Summer Arts Academy for Middle and High School Students

    Science.gov (United States)

    Danker, Stephanie; French, Kelley

    2016-01-01

    Art can provide a vehicle for animating learning. Teachers bring ideas to life through curriculum, while artists realize their ideas through images, often translating between forms, media and spaces. This paper describes the context, content and format of a residential Summer Arts Academy for gifted and talented middle and high school students,…

  7. A high-resolution vacuum ultraviolet spectrometer for plasma spectroscopy

    NARCIS (Netherlands)

    Meijer, F. G.

    1999-01-01

    A high-resolution spectrometer for the wavelength range 40-200 nm was adapted to a high-speed photo-electric detection system. A wavelength range of 3 nm can be measured up to every 0.2 ms with a resolution of 0.0012 nm and a wavelength accuracy of 0.0001 nm. The system is used for plasma spectrosco

  8. 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.

  9. High-Flux Beamline for Ultraviolet and Vacuum-Ultraviolet Circular Dichroism at NSRL

    International Nuclear Information System (INIS)

    This paper describes the commissioning and characterization of an NSRL bending magnet beamline constructed for the measurement of vacuum-ultraviolet circular dichroism on biological and other materials. The beamline provides high fluxes of ultraviolet and vacuum-ultraviolet radiation, which is converted into plane polarized light using a polarizer and subsequently converted into circularly polarized light using a photoelastic modulator with a switching frequency of 50 kHz. The beamline has the best wavelength resolution of 0.3 nm and stray light levels better than 0.03%. Example spectra of (1s)-(+)-10-camphorsulphonic acid (CSA) and myoglobin are given

  10. Influence of a vacuum region on the stability of a high-beta screw pinch

    International Nuclear Information System (INIS)

    To ascertain the influence of a vacuum region on the stability of a high-β screw pinch, the stability properties of two confinement configurations are compared. Both configurations involve diffuse equilibrium profiles and a rigid, perfectly conducting cylindrical shell. In the first problem, perfectly conducting plasma extends to the rigid conducting wall; the plasma is extremely tenuous in the outer region of the pinch, however. In the second case, profiles identical to those of the first problem are chosen for the central portion of the pinch, but the outer tenuous plasma is replaced by a perfectly insulating vacuum region. The two configruations are found to be unstable for the same range of external parameter values; different modes are unstable in the two cases, however. Thus, the presence of a vacuum region does not affect the stability boundary of the pinch, but it does affect the nature of the unstable modes

  11. 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...

  12. Technique for testing high-vacuum pump pumping-out rate

    International Nuclear Information System (INIS)

    Technique for measuring high-vacuum pump pumping-out rate using calibrated diaphragm is presented. Account of measuring chamber intrinsic gas release permits to determine pumping-out characteristics of pumps over the whole operating range of pressures, including the limiting values

  13. High-precision evaluation of four-loop vacuum bubbles in three dimensions

    CERN Document Server

    Schröder, Y

    2003-01-01

    In this letter we present a high-precision evaluation of the expansions in eps=(3-d)/2 of (up to) four-loop scalar vacuum master integrals, using the method of difference equations developed by Laporta. We cover the complete set of fully massive master integrals.

  14. Solid-film lubricant is effective at high temperatures in vacuum

    Science.gov (United States)

    Sliney, H. E.

    1966-01-01

    Calcium fluoride with a suitable inorganic binder forms a stable solid-film lubricant when fused to the surface to be lubricated. It is effective in environments at elevated temperatures and gas pressures ranging from atmospheric to high vacuum. It is not stable in reducing atmospheres.

  15. Preparation of Silver and Silver-backing self-supported thin targets by high vacuum evaporation

    CERN Document Server

    Cabanelas, P; Henriques, A; Sánchez-Benítez, A; Teubig, P; Velho, P

    2016-01-01

    We have produced in the Nuclear Physics Center in Lisbon thin film self-supported targets of Ag, LiF/Ag and CaF$_2$/Ag by a high vacuum resistance evaporation method. The production setup, materials, methods, characterization and results are described.

  16. The Effects of High-Stakes Testing Policy on Arts Education

    Science.gov (United States)

    Baker, Richard A., Jr.

    2012-01-01

    This study examined high-stakes test scores for 37,222 eighth grade students enrolled in music and/or visual arts classes and those students not enrolled in arts courses. Students enrolled in music had significantly higher mean scores than those not enrolled in music (p less than 0.001). Results for visual arts and dual arts were not as…

  17. 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.

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

    International Nuclear Information System (INIS)

    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

  19. 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.

  20. Calculation of the vacuum Green's function valid for high toroidal mode number in tokamaks.

    Science.gov (United States)

    Chance, Morrell; Turnbull, Alan

    2005-10-01

    The present evaluation of the Green's function used for the magmetic scalar potential in vacuum calculations for axisymmetric geometry in the vacuum segments of gato, pest and other mhd stability codes has been found to be deficient for moderately high toroidal mode numbers. This was due to the loss of numerical precision arising from the upward recursion relation used for generating the functions to high mode numbers. The recursion is initiated from the complete elliptic integrals of the first and second kinds. To ameliorate this, a direct integration of the integral representation of the function was crafted to achieve the necessary high accuracy for moderately high mode numbers. At very high mode numbers the loss of numerical precision due to the oscillatory behavior of the integrand is further avoided by judiciously deforming the integration contour in the complex plane. Machine precision, roughly 14 -- 16 digits, accuracy can be achieved by using a combination of both these techniques.

  1. 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.

  2. Effect of High Solenoidal Magnetic Fields on Breakdown Voltages of High Vacuum 805 MHz Cavities

    CERN Document Server

    Moretti, A; Geer, S; Qian, Z

    2004-01-01

    The demonstration of muon ionization cooling by a large factor is necessary to demonstrate the feasilibility of a collider or neutrino factory. An important cooling experiment, MICE [1], has been proposed to demonstrate 10 % cooling which will validate the technology. Ionization cooling is accomplished by passing a high-emittance beam in a multi-Tesla solenoidal channel alternately through regions of low Z material and very high accelerating RF Cavities. To determine the effect of very large solenoidal magnetic fields on the generations of Dark current, X-Rays and breakdown Voltage gradients of vacuum RF cavities, a test facility has been established at Fermilab in Lab G. This facility consists of a 12 MW 805 MHz RF station, and a large bore 5 T solenoidal superconducting magnet containing a pill box type Cavity with thin removable window apertures allowing dark current studies and breakdown studies of different materials. The results of this study will be presented. The study has shown that the peak achievab...

  3. Leybold vacuum handbook

    CERN Document Server

    Diels, K; Diels, Kurt

    1966-01-01

    Leybold Vacuum Handbook presents a collection of data sets that are essential for numerical calculation of vacuum plants and vacuum processes. The title first covers vacuum physics, which includes gas kinetics, flow phenomena, vacuum gauges, and vapor removal. Next, the selection presents data on vacuum, high vacuum process technology, and gas desorption and gettering. The text also deals with materials, vapor pressure, boiling and melting points, and gas permeability. The book will be of great interest to engineers and technicians that deals with vacuum related technologies.

  4. Annealing effect for SnS thin films prepared by high-vacuum evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Revathi, Naidu, E-mail: revathi.naidu@ttu.ee; Bereznev, Sergei; Loorits, Mihkel; Raudoja, Jaan; Lehner, Julia; Gurevits, Jelena; Traksmaa, Rainer; Mikli, Valdek; Mellikov, Enn; Volobujeva, Olga [Department of Materials Science, Tallinn University of Technology, Ehitajate tee 5, Tallinn 19086 (Estonia)

    2014-11-01

    Thin films of SnS are deposited onto molybdenum-coated soda lime glass substrates using the high-vacuum evaporation technique at a substrate temperature of 300 °C. The as-deposited SnS layers are then annealed in three different media: (1) H{sub 2}S, (2) argon, and (3) vacuum, for different periods and temperatures to study the changes in the microstructural properties of the layers and to prepare single-phase SnS photoabsorber films. It is found that annealing the layers in H{sub 2}S at 400 °C changes the stoichiometry of the as-deposited SnS films and leads to the formation of a dominant SnS{sub 2} phase. Annealing in an argon atmosphere for 1 h, however, causes no deviations in the composition of the SnS films, though the surface morphology of the annealed SnS layers changes significantly as a result of a 2 h annealing process. The crystalline structure, surface morphology, and photosensitivity of the as-deposited SnS films improves significantly as the result of annealing in vacuum, and the vacuum-annealed films are found to exhibit promising properties for fabricating complete solar cells based on these single-phase SnS photoabsorber layers.

  5. Ultra-high vacuum compatible optical chopper system for synchrotron x-ray scanning tunneling microscopy

    International Nuclear Information System (INIS)

    High-speed beam choppers are a crucial part of time-resolved x-ray studies as well as a necessary component to enable elemental contrast in synchrotron x-ray scanning tunneling microscopy (SX-STM). However, many chopper systems are not capable of operation in vacuum, which restricts their application to x-ray studies with high photon energies, where air absorption does not present a significant problem. To overcome this limitation, we present a fully ultra-high vacuum (UHV) compatible chopper system capable of operating at variable chopping frequencies up to 4 kHz. The lightweight aluminum chopper disk is coated with Ti and Au films to provide the required beam attenuation for soft and hard x-rays with photon energies up to about 12 keV. The chopper is used for lock-in detection of x-ray enhanced signals in SX-STM

  6. Vacuum system of the high energy ring of an asymmetric B-factory based on PEP

    International Nuclear Information System (INIS)

    The multi-ampere currents required for high luminosity operation of an asymmetric B factory leads to extremely stressing requirements on a vacuum system suitable for maintaining long beam-gas lifetimes and acceptable background levels in the detector. We present the design for a Cu alloy vacuum chamber and its associated pumping system for the 9 GeV electron storage ring of the proposed B factory based on PEP. The excellent thermal and photo-desorption properties of Cu allows handling the high proton flux in a conventional, single chamber design with distributed ion pumps. The x-ray opacity of the Cu is sufficiently high that no additional lead shielding is necessary to protect the dipoles from the intense synchrotron radiation generated by the beam. The design allows chamber commissioning in <500 hr of operation. 5 refs., 3 figs., 2 tabs

  7. Ultra-high vacuum compatible optical chopper system for synchrotron x-ray scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Hao, E-mail: hc000211@ohio.edu [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Nanoscale and Quantum Phenomena Institute, Physics & Astronomy Department, Ohio University, Athens, Ohio 45701 (United States); Cummings, Marvin; Shirato, Nozomi; Stripe, Benjamin; Preissner, Curt; Freeland, John W. [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Rosenmann, Daniel [Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Kersell, Heath; Hla, Saw-Wai [Nanoscale and Quantum Phenomena Institute, Physics & Astronomy Department, Ohio University, Athens, Ohio 45701 (United States); Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Rose, Volker, E-mail: vrose@anl.gov [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)

    2016-01-28

    High-speed beam choppers are a crucial part of time-resolved x-ray studies as well as a necessary component to enable elemental contrast in synchrotron x-ray scanning tunneling microscopy (SX-STM). However, many chopper systems are not capable of operation in vacuum, which restricts their application to x-ray studies with high photon energies, where air absorption does not present a significant problem. To overcome this limitation, we present a fully ultra-high vacuum (UHV) compatible chopper system capable of operating at variable chopping frequencies up to 4 kHz. The lightweight aluminum chopper disk is coated with Ti and Au films to provide the required beam attenuation for soft and hard x-rays with photon energies up to about 12 keV. The chopper is used for lock-in detection of x-ray enhanced signals in SX-STM.

  8. Development of high resolution vacuum ultraviolet beam line at Indus-1 synchrotron source

    International Nuclear Information System (INIS)

    High resolution vacuum ultraviolet beamline at Indus-1 450 MeV synchrotron source has been developed for carrying out absorption spectral studies of atoms and molecules. The beamline consists of three major parts i.e. a focusing optical system, an absorption cell and a high resolution 6.65 m vacuum ultraviolet spectrometer in Eagle mount. The wavelength range of the spectrometer is from 700 A to 2000 A and the resolution of the spectrometer is 0.01 A. Using the synchrotron source Indus-1, the absorption spectra of oxygen, ammonia and carbon disulphide have been recorded at the wavelength band of 1750 A, 1881 A and 3100 A respectively. Details of different aspects of design and development of the high resolution VUV beamline are described in this report. (author)

  9. Cavity-assisted manipulation of freely rotating silicon nanorods in high vacuum

    CERN Document Server

    Kuhn, Stefan; Kosloff, Alon; Sclafani, Michele; Stickler, Benjamin A; Nimmrichter, Stefan; Hornberger, Klaus; Cheshnovsky, Ori; Patolsky, Fernando; Arndt, Markus

    2015-01-01

    Optical control of nanoscale objects has recently developed into a thriving field of research with far-reaching promises for precision measurements, fundamental quantum physics and studies on single-particle thermodynamics. Here, we demonstrate the optical manipulation of silicon nanorods in high vacuum. Initially, we sculpture these particles into a silicon substrate with a tailored geometry to facilitate their launch into high vacuum by laser-induced mechanical cleavage. We manipulate and trace their center-of-mass and rotational motion through the interaction with an intense intra-cavity field. Our experiments show optical forces on nanorotors three times stronger than on silicon nanospheres of the same mass. The optical torque experienced by the spinning rods will enable cooling of the rotational motion and torsional opto-mechanics in a dissipation-free environment.

  10. 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.

  11. Experience of operating the large vacuum system of the KEKB collider. High stored current issues

    International Nuclear Information System (INIS)

    For the KEK B-factory, an electron-positron collider which consists of two storage rings intersecting at the collision point has been running in operation since December 1998. The ring has a circumference of 3016 m, and its vacuum chambers are mainly made of copper. Until July 2001, a fill with the initial current of 940 mA positron and 730 mA electron was established and the world record luminosity was achieved. Before the goal currents of 2.6 A positron and 1.1 A electron are achieved, the effect of high beam current has been emerging. The effect of electron cloud became evident especially in the LER. Some bellows were found to be warmed by the TE mode of beam induced fields. Direct damage by beam is seen at the surface of the movable mask. An indirect effect of the high beam current passing close to a vacuum seal is also observed. (author)

  12. 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 ...

  13. Interaction of a stream of dielectric spheres in an electric field in a high vacuum

    International Nuclear Information System (INIS)

    The interaction of a stream of dielectric spheres in an electric field in a high vacuum is investigated both theoretically and experimentally. This investigation is motivated by an elaborate attempt to detect fractional electric charges which might exist in matter, namely, a search for isolated quarks in matter. The theoretical analysis is intended for pinpointing the basic interaction mechanism by which a stream of dielectric spheres becomes destablized in an electric field. One important result of this analysis is a suggested method by which to eliminate the destabilizing forces. The experiments performed are intended to study the behavior of a stream of monodisperse dielectric liquid drops in an electric field in a high vacuum. It is seen from these experiments that the deflections of any two drops in the stream with charges differing by one electronic charge is not always the same due to the destabilization effects

  14. 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.

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

    International Nuclear Information System (INIS)

    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

  16. 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.

  17. Hardening Inspection Devices to Ultra-High Vacuum, Temperature and High Magnetic Field

    International Nuclear Information System (INIS)

    In order to demonstrate the feasibility of a mini-invasive inspection arm in ITER, the next step in fusion energy research machines, and to match the need for such a device in the French tokamak Tore Supra, a hardened long-reach robot has been developed by the CEA-LIST robotics team. The AIA (Articulated Inspection Arm), a 8 m long, highly articulated dexterous carrier with a 10 kg payload has been developed to be deployed anywhere in the Tore Supra vacuum vessel from one single 250 mm entry point, while the vessel is kept at the operating temperature (120 degrees C) and pressure (10-5 Pa). Since its successful demonstration in Tore Supra in September 2008, the robot has been identified by different teams of scientists working on the tokamak for various potential tasks, from vision to diagnostic calibration or component analysis. In order to make such a device even more available, the CEA-LIST team is now working on the magnetic field constraint on robots. The goal being to demonstrate capabilities of intervention in ITER conditions, the considered field is 4 to 8 T. Technologies, command schemes and design strategies available for an inspection robot tolerant to high magnetic field have been studied. This paper first details the different technologies chosen for the AIA. How such an inspection device has been integrated on a multidisciplinary research machine such as Tore Supra is then detailed in a second part. The paper finally presents various concepts and experimentations to be used in a magnetic field tolerant robot for inspection of a large superconductor machine. (authors)

  18. Heating of super high vacuum system in the pumping out by the nitrogen forevacuum pump

    International Nuclear Information System (INIS)

    Highvacuum system training technology by heating at chamber pressures from atmospheric to 10 mm Hg provided with nitrogen condensation pump has been suggested and tested. The small chamber warm-up to 300 deg C for several hours with further pumping out by helium high vacuum pump results in attaining partial pressures of water vapours and hydrocarbons less than 10-11 mm Hg. Large chamber warm-up of 0.5 m3 volume at temperatures about 150 deg C decreases the level of degassing of surfaces locating in vacuum by water vapours and hydrocarbons down to values about 10-10 and 10-12 mm Hg l/s-1xcm-2 respectively. It is proposed to apply the given procedure of surface decontamination when pumping out of thermonuclear system chambers

  19. 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)].

  20. High-speed imaging of explosive exoemission from an alumina ceramic in vacuum

    Science.gov (United States)

    Coaker, B. M.; Xu, N. S.; Jones, F. J.; Latham, R. V.

    1994-05-01

    A fast-video imaging technique was used to observe the pulsed breakdown behavior of an alumina tube, having two concentric planar electrodes on its end-face. Voltage-pulses, typically of 5 kV amplitude (5 kV microsecond(s) -1 time rate-of-rise), were applied to the radial M-I-M insulator-electrode regime under ultra-high vacuum (pressure < 10-8 Torr), with video recordings made at 1000 frames per second. Images of the observed breakdown phenomena are presented, viewing along the center-axis and also in the plane of the M-I-M structure. These images are discussed in relation to plasma-jets associated with vacuum arcs, and the nature of the ion species within such jets.

  1. 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.

  2. 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...

  3. 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...

  4. Windowless transition between atmospheric pressure and high vacuum via differential pumping for synchrotron radiation applications.

    Science.gov (United States)

    Gog, T; Casa, D M; Kuzmenko, I; Krakora, R J; Bolin, T B

    2007-07-01

    A differential pump assembly is introduced which can provide a windowless transition between the full atmospheric pressure of an in-air sample environment and the high-vacuum region of a synchrotron radiation beamline, while providing a clear aperture of approximately 1 mm to pass through the X-ray beam from a modern third-generation synchrotron radiation source. This novel pump assembly is meant to be used as a substitute for an exit vacuum window on synchrotron beamlines, where the existence of such a window would negatively impact the coherent nature of the X-ray beam or would introduce parasitic scattering, distorting weak scattering signals from samples under study. It is found that the length of beam pipe necessary to reduce atmospheric pressure to below 10 mbar is only about 130 mm, making the expected photon transmission for hard X-rays through this pipe competitive with that of a regular Be beamline window. This result is due to turbulent flow dominating the first pumping stage, providing a mechanism of strong gas conductance limitation, which is further enhanced by introducing artificial surface roughness in the pipe. Successive reduction of pressure through the transitional flow regime into the high-vacuum region is accomplished over a length of several meters, using beam pipes of increasing diameter. While the pump assembly has not been tested with X-rays, possible applications are discussed in the context of coherent and small-angle scattering. PMID:17587659

  5. Femtosecond laser ablation of aluminum in vacuum and air at high laser intensity

    International Nuclear Information System (INIS)

    In this study, the ablation of aluminum by a near-infrared femtosecond laser pulse (800 nm, 100 fs) at different intensity is investigated by a two-dimensional hydrodynamic model. The ablation rates are compared between the cases in vacuum and in air over a wide range of laser power density. It has been reported before that at low (13 W/cm2) and moderate laser intensity (1013–1014 W/cm2), two different ablation regimes exist, and the ablation depth per pulse is dependent on the optical penetration depth and electron heat penetration depth, respectively. By considering both collisional and collisionless absorptions, the model in this study predicts the third ablation regime with a much higher ablation rate increase with respect to laser intensity in the high intensity range (>1014 W/cm2) in vacuum, which shows good agreement with the experimental data. This phenomenon is attributed to the change of dominant absorption mechanism from collisional to collisionless absorption. For the case in air, the ablation depth increases slowly with the laser intensity in the high intensity regime, and is much smaller than that in vacuum. It is revealed that this is due to the strong early plasma-laser interaction in air.

  6. Cooling the 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

    2016-01-01

    Levitated diamond nanocrystals with nitrogen-vacancy (NV) centres in high vacuum have been proposed as a unique system for experiments in fundamental quantum mechanics, including the generation of large quantum superposition states and tests of quantum gravity. This system promises extreme isolation from its environment while providing quantum control and sensing through the NV centre spin. While optical trapping has been the most explored method of levitation, recent results indicate that excessive optical heating of the nanodiamonds under vacuum may make the method impractical with currently available materials. Here, we study an alternative magneto-gravitational trap for diamagnetic particles, such as diamond nanocrystals, with stable levitation from atmospheric pressure to high vacuum. Magnetic field gradients from permanent magnets confine the particle in two dimensions, while confinement in the third dimension is gravitational. We demonstrate that feedback cooling of the centre-of-mass motion of a trapped nanodiamond cluster results in cooling of one degree of freedom to less than 1 K. PMID:27444654

  7. Arts Education in a High-Stakes Environment. The Informed Educator Series

    Science.gov (United States)

    Tucker, Carrie

    2007-01-01

    What is the place of the arts in our schools? In a world of high-stakes testing and accountability, can schools "afford" to teach the arts? This "Informed Educator" explores why many who have studied this issue consider the arts to have an important role in the curriculum. Examples of the ways some leaders effectively communicate the benefits of…

  8. Research on the development of high-level martial-art teams of universities in Shanghai

    Directory of Open Access Journals (Sweden)

    MING Lei

    2014-06-01

    Full Text Available Five Universities with high level martial art sport teams in Shanghai have been chosen for research to initiate a comprehensive investigation and analysis for following aspects during establishment and development of the martial-art teams: status of athletes and coachers, status of learning and training of martial-art teams, martial-art team stimulating system and logistic support by using documentary, questionnaire survey, interview and mathematic survey, so as to find existing disadvantages and their relevant solutions.

  9. 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...

  10. Rolling contact fatigue in high vacuum using ion plated nickel-copper-silver solid lubrication

    International Nuclear Information System (INIS)

    Ion plated, nickel-copper-silver coated steel ball bearings that were tested in rolling contact fatigue (RCF) experiments in high vacuum are presented in this article. ANSI T5 ball bearings were coated with approximately 10 nm of nickel-copper followed by 100 nm of silver using a dc ion plating process. The balls were then tested for RCF in vacuum in the 10-7 Torr range at 130 Hz rotational speed and at 4.1 GPa Hertzian contact stress. The significance of this work is in the extension of RCF testing to an ultrahigh vacuum (UHV) application using silver as a lubricant instead of oil. The effects of pressure and voltage on the ion plating process were also investigated using scanning electron microscopy and RCF life testing in UHV. Test results with a ball size of 5/16 in. in UHV show that deposition at voltages greater than 2.5 kV shortens the RCF life and introduces a unique failure mode. Voltage and pressure fluctuations during the deposition process result in significant thickness monitor measurement errors as well. A regulator control scheme that minimizes the process pressure overshoot is also simulated.

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

    International Nuclear Information System (INIS)

    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.

  12. Preventing and reversing vacuum-induced optical losses in high-finesse tantalum (V) oxide mirror coatings

    OpenAIRE

    Gangloff, Dorian; Shi, Molu; Wu, Tailin; Bylinskii, Alexei; Braverman, Boris; Nichols, Rosanna; Li, Junru; Aichholz, Kai; Cetina, Marko; Karpa, Leon; Chuang, Isaac; Gutierrez, Michael Steven; Jelenkovic, Branislav; Vuletic, Vladan

    2015-01-01

    High-finesse optical cavities placed under vacuum are foundational platforms in quantum information science with photons and atoms. We study the vacuum-induced degradation of high-finesse optical cavities with mirror coatings composed of SiO[subscript 2]-Ta[subscript 2]O[subscript 5] dielectric stacks, and present methods to protect these coatings and to recover their initial low loss levels. For separate coatings with reflectivities centered at 370 nm and 422 nm, a vacuum-induced continuous ...

  13. The design of high vacuum system for baby electron beam machine (baby ebm): a comparison between theoretical and experimental

    International Nuclear Information System (INIS)

    Baby ebm which was developed to study the engineering and physics of electrons requires the use of high vacuum system in order to prevent electron loss and ionization of air molecules. In selecting the high vacuum system for baby ebm two main factors were considered: the ultimate pressure and the pump down time. The ultimate pressure required for the operation of the baby ebm is in 10-7 torr range. The pump down time was estimated from calculations, taking into account the vacuum pump and chamber size. The turbomolecular pump system (tmp), which is capable of achieving the required vacuum level was selected as the high vacuum system and installed to baby ebm. The tmp is currently fully operational. It was found that the vacuum pumping performance of the tmp differs considerably from what the calculations indicate. Compared to the calculations, it takes a much longer time to achieve the required operating pressure of baby ebm. This could be due to the fact that the formula used for the calculations was a very simplified formula that takes into account the main factors only which are the vacuum pump and chamber size. This paper attempts to present the comparison of the tmp performance between the theoretical and experimental. (Author)

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

    Science.gov (United States)

    Fang, Yurui; Zhang, Zhenglong; Sun, Mengtao

    2016-03-01

    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(-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. PMID:27036755

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

    Science.gov (United States)

    Fang, Yurui; Zhang, Zhenglong; Sun, Mengtao

    2016-03-01

    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 10-7 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.

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

    Science.gov (United States)

    Bauer, A.; Neubauer, A.; Münzer, W.; Regnat, A.; Benka, G.; Meven, M.; Pedersen, B.; Pfleiderer, C.

    2016-06-01

    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 the 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 bars. 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.

  17. 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.

  18. Visualisation of natural aquatic colloids and particles - A comparison of conventional high vacuum and environmental scanning electron microscopy

    OpenAIRE

    Doucet, F. J.; Lead, J. R.; Maguire, L.; Achterberg, Eric P.; Millward, G. E.

    2005-01-01

    The applicability of environmental scanning electron microscopy (ESEM; imaging of hydrated samples) and conventional high vacuum scanning electron microscopy (SEM; imaging of dried samples at high vacuum) for the observation of natural aquatic colloids and particles was explored and compared. Specific attention was given to the advantages and limitations of these two techniques when used to assess the sizes and morphologies of complex and heterogeneous environmental systems. The observation o...

  19. Visualisation and art articulation of high school students

    OpenAIRE

    Jakša, Janja

    2016-01-01

    When a child enters adolescent age, his or her art development is coming to an end. That is, in this period their wish for expression in the field of art is dwindling, however, at the same time the wish for individual visual expression becomes stronger and often also the tendency for clichéd artistic representation. Using an appropriate teaching method and especially through transposition and alternative techniques, the teacher can succeed in greatly boosting the imagination of young people g...

  20. Study on vacuum brazing of high purity alumina for application in proton synchrotron

    International Nuclear Information System (INIS)

    Highlights: • Study compares Mo–Mn metallization and active brazing routes for joining alumina. • Targeted application: UHV chamber of proton synchrotron. • Both kinds of joints were UHV compatible with helium leak rate <1.1 × 10−10 mbar l/s. • Active brazed joints met tensile and flexural strength design requirement (>50 MPa). • Active brazing is a simpler and economical route for joining high purity alumina. - Abstract: The paper describes an experimental study to evaluate two different vacuum brazing processes to obtain high purity alumina (99.7%) joints suitable for application in rapid cycle proton synchrotron. Two different brazing routes, adopted for making alumina–alumina brazed joints, included (i) multi-step Mo–Mn metallization, followed by brazing with BVAg-8 alloy and (ii) advanced single-step active brazing with CuSil-ABA® alloy. Both the brazing routes yielded helium leak tight and ultra-high vacuum (pressure < 10−9 mbar) compatible joints. Active-brazed specimens exhibited tensile and mean flexural strengths of 62 and 110 MPa, respectively. Metallized-brazed specimens, although associated with relatively lower tensile strength (35 MPa) than the targeted value (>50 MPa), displayed higher mean flexural strength of 149 MPa. The results of the study demonstrated that active brazing is a simple and cost effective alternative to conventional multi-step metallization route for producing quality joints of high purity alumina for application in rapid cycle proton synchrotron machine

  1. Use of high-thermal conductive aluminum nitride based ceramics in vacuum UHF electronic devices

    Directory of Open Access Journals (Sweden)

    Chasnyk V. I.

    2013-06-01

    Full Text Available Analysis of properties and characteristics of the alumina, beryllium oxide and aluminum nitride based ceramic materials used in UHF electronic devices has been made. It was shown that the complex of parameters including structural and functional characteristics of the high-thermal conductive aluminum nitride ceramics prevail over all types of alumina ceramics and is not lower than the same characteristics of the beryllium oxide ceramics especially at the temperatures higher than 450 °C. The examples of the prevailing use of the aluminum nitride ceramics inside vacuum UHF-region devices: TWT’s and klystrons.

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

    International Nuclear Information System (INIS)

    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

  3. 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.

  4. Low loss hollow optical-waveguide connection from atmospheric pressure to ultra-high vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Ermolov, A.; Mak, K. F.; Tani, F.; Hölzer, P.; Travers, J. C. [Max Planck Institute for the Science of Light, Günther-Scharowsky-Str. 1, 91058 Erlangen (Germany); Russell, P. St. J. [Max Planck Institute for the Science of Light, Günther-Scharowsky-Str. 1, 91058 Erlangen (Germany); Department of Physics, University of Erlangen-Nuremberg, Günther-Scharowsky-Str. 1, 91058 Erlangen (Germany)

    2013-12-23

    A technique for optically accessing ultra-high vacuum environments, via a photonic-crystal fiber with a long small hollow core, is described. The small core and the long bore enable a pressure ratio of over 10{sup 8} to be maintained between two environments, while permitting efficient and unimpeded delivery of light, including ultrashort optical pulses. This delivery can be either passive or can encompass nonlinear optical processes such as optical pulse compression, deep UV generation, supercontinuum generation, or other useful phenomena.

  5. The reduction and distillation of isotopically enriched zinc oxides under high vacuum conditions

    International Nuclear Information System (INIS)

    Historically, enriched zinc (Zn) metal was produced at the Oak Ridge National Laboratory's Isotope Enrichment Facility (IEF) by either electrodeposition, followed by melting to produce a metal ingot, or purified by hydrogen reduction and distillation at atmospheric pressure in a tube furnace as a prelude to electroplating. Electroplated material was generally poor in quality, and losses were high during subsequent melting. Adapting the distillation purifying technique as an ultimate means of recovery of Zn metal proved to be difficult and inefficient. To resolve these problems, the well-established vacuum reduction/distillation process was adapted for the conversion of Zn oxide to metal

  6. An ultra-high-vacuum multiple grating chamber and scan drive with improved grating change

    International Nuclear Information System (INIS)

    We describe a new grating chamber and scan drive which has been designed, built, and tested by Physical Sciences Laboratory of the University of Wisconsin for the new high flux, high-resolution spectroscopy branch line of the TOK hybrid wiggler/undulator on the NSLS VUV ring. The chamber will contain spherical gratings to be used in the Spherical Grating Monochromator (SGM) configuration introduced by Chen and Sette. The grating chamber houses five 180 mm x 35 mm x 30 mm gratings capable of scanning a range of 12 degree (-14 degree to +8 degree with respect to the incoming beam direction) for VUV and soft X-ray diffraction. The gratings can be switched and precisely indexed while under ultra-high vacuum (UHV) at any scan angle and are mechanically isolated from the vacuum chamber to prevent inaccuracies due to chamber distortions. The gratings can separately be adjusted for height, yaw, pitch, and roll, with the latter three performed while in vacuo. The scan drive provides a resolution of 0.03 arc sec with linearity over the 12 degree range of ∼1.5 arc sec and absolute reproducibility of 1 arc sec. 5 refs., 5 figs

  7. Avtomatizacija postopka naprševanja na laboratorijskem visokovakuumskem sistemu: Automation of the sputtering process on high vacuum lab system:

    OpenAIRE

    Berič, Boris; Drab, Marjan; Pregelj, Andrej; Sulčič, Slavko

    1997-01-01

    The modern vacuum systems have valves and other elements PC or PLC controlled. For safety reasons all movements are checked in real time and adapted to real values of pressure temperature, current, thickness of sputtering layer, etching time etc. Motion, pressure and other sensors are essential. In data analyzing and motion control microprocessor plays important role. This article describes development of automated module for controlling the Lab High Vacuum System.

  8. Energetic high-voltage breakdowns in vacuum over a large gap for ITER neutral beam accelerator

    International Nuclear Information System (INIS)

    Highlights: ► We performed energetic high voltage breakdowns up to 370 kV with a stored energy of 1 kJ. ► No breakdowns at 200 kV could be produced over a gap of 85 mm using 100 cm2 copper electrodes. ► Electrodes damage was visible after the experiment. ► The number of arcs impacts is orders of magnitude above the number of breakdowns. -- Abstract: CEA has undertaken tests to study the resilience of copper electrodes in vacuum against energetic high-voltage breakdowns using external capacitors to provide the energy. Earlier tests succeeded in dissipating a maximum of 150 J in a 30 mm gap, limited by the equivalent series resistance (ESR) in the external capacitors. Using new ones with an ESR that is a factor of 10 lower it was unsuccessfully tried to produce breakdowns at 200 kV over the 85 mm gap, despite the use of a UV flash lamp and a “field enhancement ring” (FER) that locally increased the electric field on the cathode by 50%. Consequently, the breakdowns had to be produced by raising the voltage to 300–350 kV while maintaining the gap at 85 mm. During these tests, single breakdowns dissipated up to 1140 J in the 85 mm vacuum gap. Inspection of the electrodes revealed that substantial amounts of copper appear have been evaporated from the anode and deposited on to the cathode. Also electrode deconditioning occurred

  9. 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.

  10. Induced pulse discharge formation along dielectric surface in high-current vacuum switches

    International Nuclear Information System (INIS)

    For low-inductive high-current switches of capacitive high-energy storages an effective method of fast pulsed discharge formation induced by triggering sparks in the form of a plasma layer along dielectric surface in technical vacuum of 10-2-10-1 Pa is developed and studied. Comparative results of experimental study of delay times of controlled switch triggering at voltages considerably lower than static breakdown; switching time at current variation in the control circuit and initial pressure in case of control by triggering spark at the cathode far from the dilectric wall and just near the wall are given. Development of high-current discharge induced near the dielectric surface is caused mainly by electron-avalanche processes in a layer of gas desorbed from this surface

  11. 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.

  12. 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.

  13. 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.

  14. 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)

  15. 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.

  16. High risk of ART non-adherence and delay of ART initiation among HIV positive double orphans in Kigali, Rwanda.

    Directory of Open Access Journals (Sweden)

    Kimiyo Kikuchi

    Full Text Available BACKGROUND: To reduce HIV/AIDS related mortality of children, adherence to antiretroviral treatment (ART is critical in the treatment of HIV positive children. However, little is known about the association between ART adherence and different orphan status. The aims of this study were to assess the ART adherence and identify whether different orphan status was associated with the child's adherence. METHODS: A total of 717 HIV positive children and the same number of caregivers participated in this cross-sectional study. Children's adherence rate was measured using a pill count method and those who took 85% or more of the prescribed doses were defined as adherent. To collect data about adherence related factors, we also interviewed caregivers using a structured questionnaire. RESULTS: Of all children (N = 717, participants from each orphan category (double orphan, maternal orphan, paternal orphan, non-orphan were 346, 89, 169, and 113, respectively. ART non-adherence rate of each orphan category was 59.3%, 44.9%, 46.7%, and 49.7%, respectively. The multivariate analysis indicated that maternal orphans (AOR 0.31, 95% CI 0.12-0.80, paternal orphans (AOR 0.35, 95% CI 0.14-0.89, and non-orphans (AOR 0.45, 95% CI 0.21-0.99 were less likely to be non-adherent compared to double orphans. Double orphans who had a sibling as a caregiver were more likely to be non-adherent. The first mean CD4 count prior to initiating treatment was 520, 601, 599, and 844 (cells/ml, respectively (p<0.001. Their mean age at sero-status detection was 5.9, 5.3, 4.8, and 3.9 (year old, respectively (p<0.001. CONCLUSIONS: Double orphans were at highest risk of ART non-adherence and especially those who had a sibling as a caregiver had high risk. They were also in danger of initiating ART at an older age and at a later stage of HIV/AIDS compared with other orphan categories. Double orphans need more attention to the promote child's adherence to ART.

  17. Dynamic vacuum analysis for APS high heat flux beamline front ends using optical ray-tracing simulation methods

    International Nuclear Information System (INIS)

    The high-power and high-flux x-ray beams produced by third generation synchrotron radiation sources such as the Advanced Photon Source (APS) can cause significantly high gas desorption rates on beamline front-end components if beam missteering occurs. The effect of this gas desorption needs to be understood for dynamic vacuum analysis. To simulate beam missteering conditions, optical ray-tracing methods have been employed. The results of the ray-tracing analysis have been entered into a system-oriented vacuum program to provide dynamic vacuum calculations for determination of pumping requirements for the beamline front-ends. The APS will provide several types of synchrotron radiation sources, for example, undulators, wigglers, and bending magnets. For the purpose of this study, the wiggler source was chosen as a ''worst case'' scenario due to its high photon flux, high beam power, and relatively large beam cross section

  18. Dynamic vacuum analysis for APS high heat flux beamline front ends using optical ray-tracing simulation methods

    International Nuclear Information System (INIS)

    The high-power and high-flux x-ray beams produced by third generation synchrotron radiation sources such as the Advanced Photon Source (APS) can cause significantly high gas desorption rates on beamline front-end components if beam missteering occurs. The effect of this gas desorption needs to be understood for dynamic vacuum analysis. To simulate beam missteering conditions, optical ray-tracing methods have been employed. The results of the ray-tracing analysis have been entered into a system-oriented vacuum program to provide dynamic vacuum calculations for determination of pumping requirements for the beamline front-ends. The APS will provide several types of synchrotron radiation sources, for example, undulators, wigglers, and bending magnets. For the purpose of this study, the wiggler source was chosen as a worst case scenario due to its high photon flux, high beam power, and relatively large beam cross section

  19. Development and high power RF test of the vacuum feed through for KSTAR ICRF antenna

    International Nuclear Information System (INIS)

    A 1-MW vacuum feed through for the KSTAR ICRF antenna is fabricated and high power RF test is performed. It is designed to have two alumina(Al2O3) ceramic cylinders and O-ring seal instead of a brazed seal for good mechanical and thermal strength, which is important in long pulse or steady state operation. For cooling of the ceramic, dry air is circulated in a space between the two cylinders and the outer conductor. Independent cooling water channels are installed to cool the inner conductor of the feed through. RF high voltage test is performed using two kinds of ceramics with the purities of 99.7% and 97%. Stable operation is possible with the RF voltage of 30 kVp at long pulse of 300 sec without any severe damage

  20. A vacuum tolerant high voltage system with a low noise and low power Cockcroft–Walton photomultiplier base

    International Nuclear Information System (INIS)

    We developed a high voltage system for the electromagnetic calorimeter of the KOTO detector. The system is designed around a low noise, low power Cockcroft–Walton (CW) photomultiplier tube base with a high gain preamplifier. The low power makes it suitable for operations in vacuum. The low noise and high gain allow detecting signals in the 1 MeV range. We achieved a final noise level below 180μVrms for a preamplifier gain of more than 40. A vacuum tolerant control system for the CW bases power distribution was also designed. This system is able to control and monitor the high voltage of each individual base

  1. A vacuum tolerant high voltage system with a low noise and low power Cockcroft–Walton photomultiplier base

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, T., E-mail: taka@scphys.kyoto-u.ac.jp [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Iwai, E. [Department of Physics, Osaka University, Osaka 560-0043 (Japan); Kawasaki, N. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Kim, E.J. [Division of Science Education, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Komatsubara, T.K. [High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan); Lee, J.W. [Department of Physics, Osaka University, Osaka 560-0043 (Japan); Lim, G.Y. [High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan); Maeda, Y.; Naito, D.; Nanjo, H. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Nomura, T. [High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan); Ri, Y.D. [Department of Physics, Osaka University, Osaka 560-0043 (Japan); Sasao, N. [Research Core for Extreme Quantum World, Okayama University, Tsushima-naka 3-1-1 Kita-ku, Okayama 700-8530 (Japan); Sato, K. [Department of Physics, Osaka University, Osaka 560-0043 (Japan); Seki, S. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Shiomi, K.; Sugiyama, Y.; Togawa, M. [Department of Physics, Osaka University, Osaka 560-0043 (Japan); Watanabe, H. [High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan); Yamanaka, T. [Department of Physics, Osaka University, Osaka 560-0043 (Japan)

    2014-05-11

    We developed a high voltage system for the electromagnetic calorimeter of the KOTO detector. The system is designed around a low noise, low power Cockcroft–Walton (CW) photomultiplier tube base with a high gain preamplifier. The low power makes it suitable for operations in vacuum. The low noise and high gain allow detecting signals in the 1 MeV range. We achieved a final noise level below 180μV{sub rms} for a preamplifier gain of more than 40. A vacuum tolerant control system for the CW bases power distribution was also designed. This system is able to control and monitor the high voltage of each individual base.

  2. An (ultra) high-vacuum compatible sputter source for oxide thin film growth

    Energy Technology Data Exchange (ETDEWEB)

    Mayr, Lukas; Köpfle, Norbert; Auer, Andrea; Klötzer, Bernhard; Penner, Simon [Institute for Physical Chemistry, University of Innsbruck, Innrain 52a, A-6020 Innsbruck (Austria)

    2013-09-15

    A miniaturised CF-38 mountable sputter source for oxide and metal thin film preparation with enhanced high-vacuum and ultra-high-vacuum compatibility is described. The all home-built sputtering deposition device allows a high flexibility also in oxidic sputter materials, suitable deposition rates for preparation of films in the nm- and the sub-monolayer regime and excellent reliability and enhanced cleanliness for usage in UHV chambers. For a number of technologically important – yet hardly volatile – materials, the described source represents a significant improvement over thermal deposition techniques like electron-beam- or thermal evaporation, as especially the latter are no adequate tool to prepare atomically clean layers of refractory oxide materials. Furthermore, it is superior to commercially available magnetron sputter devices, especially for applications, where highly reproducible sub-monolayer thin film preparation under very clean UHV conditions is required (e.g., for studying phase boundary effects in catalysis). The device in turn offers the usage of a wide selection of evaporation materials and special target preparation procedures also allow the usage of pressed oxide powder targets. To prove the performance of the sputter-source, test preparations with technologically relevant oxide components, comprising ZrO{sub 2} and yttrium-stabilized ZrO{sub 2}, have been carried out. A wide range of characterization methods (electron microscopy, X-ray photoelectron spectroscopy, low-energy ion scattering, atomic force microscopy, and catalytic testing) were applied to demonstrate the properties of the sputter-deposited thin film systems.

  3. Investigation of the thermally induced laser beam distortion associated with vacuum compressor gratings in high energy and high average power femtosecond laser systems

    OpenAIRE

    Fourmaux, S.; Serbanescu, C.; Lecherbourg, L; S. Payeur; Martin, F.; Kieffer, J.C.

    2009-01-01

    We report successful compensation of the thermally induced laser beam distortion associated with high energy 110 mJ and high average power femtosecond laser system of 11 Watts operated with vacuum compressor gratings. To enhance laser-based light source brightness requires development of laser systems with higher energy and higher average power. Managing the high thermal loading on vacuum optical components is a key issue in the implementation of this approach. To our knowledge this is the fi...

  4. A vacuum tolerant high voltage system with a low noise and low power Cockcroft–Walton photomultiplier base

    OpenAIRE

    Masuda, T.; Iwai, E.; Kawasaki, N; Kim, E. J.; Komatsubara, T. K.; Lee, J.W.; Lim, G. Y.; Maeda, Y.; Naito, D.; Nanjo, H.; Nomura, T.; Ri, Y. D.; Sasao, N.; Sato, K.; Seki, S.

    2014-01-01

    We developed a high voltage system for the electromagnetic calorimeter of the KOTO detector. The system is designed around a low noise, low power Cockcroft–Walton (CW) photomultiplier tube base with a high gain preamplifier. The low power makes it suitable for operations in vacuum. The low noise and high gain allow detecting signals in the 1 MeV range. We achieved a final noise level below 180 μV[rms] for a preamplifier gain of more than 40. A vacuum tolerant control system for the CW bases p...

  5. Development of non-destructive vacuum testing system using high frequency spark generator for sterile evacuated vials verification

    International Nuclear Information System (INIS)

    Sterile evacuated vial (SEV) used for elution of 99mTc from the 99mTc/99Mo generator for radiopharmaceuticals preparation have direct impact on the capability and product sterility. Conventional visual inspection by puncture tests may detect level of vacuum within SEV, but this technique is rather a destructive procedure. A non-destructive vacuum testing is thus considered highly desirable. A new system for checking the vacuum of SEV has been developed to provide rapid, reliable and non-destructive procedure. Vacuum verification were made in a set of thirty 10 ml clear glass tubing SEV with pre-control 20% failure pattern. The SEV was placed in the multipoint test compartment, according to pre-defined pattern and a high frequency, low voltage is applied to the electrical discharge distribution plate to ionized residual gas within the SEV. The glow discharge within the SEV ware transmitted via light guide module (LGM) and recorded as high resolution color images. The images are then subjected to image processing and analysis using HSL color space algorithm. The testing was repeated using 3 different test patterns. The results of this experiment show that the system was adhere to the pre-defined patterns. These types of testing for verification would not be possible with a destructive testing method. The system, provide a virtually instant verification of the presence of vacuum, selecting against simple pass/fail criteria or reporting quantitative testing of vacuum level. The ability of nondestructively vacuum testing over a short period of time in substantial quantity in a single container can reduce the cost and time for testing while providing for more meaningful data for decision making. (Author)

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

    International Nuclear Information System (INIS)

    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 μPCVD 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 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

  7. 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.

  8. 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.

  9. 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...

  10. Native defects in ultra-high vacuum grown graphene islands on Cu(1 1 1)

    International Nuclear Information System (INIS)

    We present a scanning tunneling microscopy (STM) study of native defects in graphene islands grown by ultra-high vacuum decomposition of ethylene on Cu(1 1 1). We characterize these defects through a survey of their apparent heights, atomic-resolution imaging, and detailed tunneling spectroscopy. Bright defects that occur only in graphene regions are identified as C site point defects in the graphene lattice and are most likely single C vacancies. Dark defect types are observed in both graphene and Cu regions, and are likely point defects in the Cu surface. We also present data showing the importance of bias and tip termination to the appearance of the defects in STM images and the ability to achieve atomic resolution. Finally, we present tunneling spectroscopy measurements probing the influence of point defects on the local electronic landscape of graphene islands. (paper)

  11. Harvesting Robots for High-value Crops: State-of-the-art Review and Challenges Ahead

    NARCIS (Netherlands)

    Bac, C.W.; Henten, van E.; Hemming, J.; Edan, Y.

    2014-01-01

    This review article analyzes state-of-the-art and future perspectives for harvesting robots in high-value crops. The objectives were to characterize the crop environment relevant for robotic harvesting, to perform a literature review on the state-of-the-art of harvesting robots using quantitative me

  12. 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.

  13. English Teaching Strategies Research--Based on the Vocational High School Art Students’Learning Style

    Institute of Scientific and Technical Information of China (English)

    Sun Jianxia

    2014-01-01

    Diagnosing learners' learning style is meaningful for “student-centered” teaching mode and individualized teaching.But the teaching strategies based on the students' learning style should gain the same attention.Seldom do researchers regard vocational high school art students as their subjects.Using Reid’s Perceptual Learning Style Survey as the research instrument, this paper viewed vocational high school art students as the subjects;the purpose is to find some effective strategies to teach art students of vocational high school well.

  14. English Teaching Strategies Research——Based on the Vocational High School Art Students’ Learning Style

    Institute of Scientific and Technical Information of China (English)

    Sun; Jianxia

    2014-01-01

    Diagnosing learners’ learning style is meaningful for "student一centered" teaching mode and individualized teaching.But the teaching strategies based on the students’ learning style should gain the same attention.Seldom do researchers regard vocational high school art students as their subjects.Using Reid’s Perceptual Learning Style Survey as the research instrument, this paper viewed vocational high school art students as the subjects; the purpose is to find some effective strategies to teach art students of vocational high school well.

  15. STG-CT: High-vacuum plume test facility for chemical thrusters

    OpenAIRE

    Grabe, Martin

    2016-01-01

    The STG-CT, operated by the DLR Institute for Aerodynamics and Flow Technology in Göttingen, is a vacuum facility specically designed to provide and maintain a space-like vacuum environment for researching plume flow and plume impingement from satellite reaction control thrusters. Its unique liquid-helium driven cryopump of 30m2 allows maintaining a background pressure

  16. Mirror movement mechanism in ultra high vacuum for synchrotron radiation mirror box

    International Nuclear Information System (INIS)

    In a synchrotron radiation (SR) beamline pre and post mirrors are important optical components for precisely focussing SR on a monochromator and on the target in an experimental station. These mirrors are mounted in the ultra high vacuum chamber (UHV) along with high precision mirror movement mechanism. The mirror movement mechanism provides backlash free six degrees of freedom to the mirror. Three precision motions are linear in nature and three are rotational. Two rotational precision motions are performed by elastic movement of spring steel fork with a backlash free resolution of 10 arc seconds and with a range of 0 to +/-1 degree. The another rotational motion has been performed by angular displacement of a plate through precision high tensile bolts with backlash free resolution of 10 arc seconds and with a range of 0 to +/-1 degree. Three linear motions have been performed by linear displacement of a plate through precision high tensile bolts with backlash free resolution of 10 microns with a range of 0 to +/- 10 mm. Two rotational precision motions are transferred to the mirror in UHV through a bellow and other four precision motions are transferred through the UHV chamber. (author). 3 refs., 2 figs

  17. Ultra high vacuum activities and required modification at 14 UD BARC-TIFR pelletron accelerator facility

    International Nuclear Information System (INIS)

    Full text: The 14 UD pelletron accelerator is working round the clock since 1989. The accelerator is housed inside a tank which is 6 meter in diameter and 25 meter long. The accelerator tank is pressurized with SF6 at 80 to 100 PSIG in order to achieve 14MV. In pelletron, ions are extracted from SNICS are pre-accelerated up to 300 keV before being injected into low energy accelerator tube. In the terminal which is at high potential (4MV to 14 MV), the ion beam pass through the stripper and positive ions with high charge states are produced. The high energy beams are focussed and analyzed by 90 deg magnet. The analyzed beam is then transported to the various experimental ports. In order to achieve uniform ultra high vacuum (to reduce the loss of intensity and spread in the energy of ions beams) in more than 100 metre and 100 mm diameter beam lines including magnet chambers and various beam diagnostic devices, combination of getter-ion pumps and turbo pumps are being used at Pelletron Accelerator Facility. The 14 UD pelletron is equipped with a combination of foil and gas stripper in high voltage terminal section. The foil and gas stripper in the terminal section are mainly used for stripping of light and heavy ions respectively. The gas stripper plays a great role for stripping of heavy ions and its efficiency depends on gas stripper parameters and supporting pumps. The gas stripper is originally installed with getter pumps. These pumps required periodic replacement of titanium cartridges and slowly the pumping speed used to diminish with time. A new recirculation turbo molecular pumps based system is being designed to improve good beam transmission. Details of design will be presented. Proton beam of tens of MeV energy and μA range current is in demand to carry out specific radiochemistry experiments in this facility. It is proposed to built and accommodate a proton experimental setup in the tower area of the existing facility. Details of required UHV system for

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

    International Nuclear Information System (INIS)

    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 JxB 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 80-90 eV, which is confirmed by Langmuir electric probe measurements. Density ne of this metal plasma is shown to be in the range 4x1021-6x1021 m-3 and includes multiple ion charge states. The exit velocity of the plasma measured by a pair of Langmuir probes is close to 2.2x106 cm/s and matched well with the arc velocity determined by the B-dot probes and the results from simulation

  19. Modeling of the anode surface deformation in high-current vacuum arcs with AMF contacts

    Science.gov (United States)

    Huang, Xiaolong; Wang, Lijun; Deng, Jie; Jia, Shenli; Qin, Kang; Shi, Zongqian

    2016-02-01

    A high-current vacuum arc subjected to an axial magnetic field is maintained in a diffuse status. With an increase in arc current, the energy carried by the arc column to the anode becomes larger and finally leads to the anode temperature exceeding the melting point of the anode material. When the anode melting pool is formed, and the rotational plasma of the arc column delivers its momentum to the melting pool, the anode melting pool starts to rotate and also flow outwards along the radial direction, which has been photographed by some researchers using high-speed cameras. In this paper, the anode temperature and melting status is calculated using the melting and solidification model. The swirl flow of the anode melting pool and deformation of the anode is calculated using the magneto-hydrodynamic (MHD) model with the volume of fraction (VOF) method. All the models are transient 2D axial-rotational symmetric models. The influence of the impaction force of the arc plasma, electromagnetic force, viscosity force, and surface tension of the liquid metal are all considered in the model. The heat flux density injected into the anode and the arc pressure are obtained from the 3D numerical simulation of the high-current vacuum arc using the MHD model, which gives more realistic parameters for the anode simulation. Simulation results show that the depth of the anode melting pool increases with an increase in the arc current. Some droplets sputter out from the anode surface, which is caused by the inertial centrifugal force of the rotational melting pool and strong plasma pressure. Compared with the previous anode melting model without consideration of anode deformation, when the deformation and swirl flow of the anode melting pool are considered, the anode temperature is relatively lower, and just a little more than the melting point of Cu. This is because of liquid droplets sputtering out of the anode surface taking much of the energy away from the anode surface. The

  20. Modeling of the anode surface deformation in high-current vacuum arcs with AMF contacts

    International Nuclear Information System (INIS)

    A high-current vacuum arc subjected to an axial magnetic field is maintained in a diffuse status. With an increase in arc current, the energy carried by the arc column to the anode becomes larger and finally leads to the anode temperature exceeding the melting point of the anode material. When the anode melting pool is formed, and the rotational plasma of the arc column delivers its momentum to the melting pool, the anode melting pool starts to rotate and also flow outwards along the radial direction, which has been photographed by some researchers using high-speed cameras. In this paper, the anode temperature and melting status is calculated using the melting and solidification model. The swirl flow of the anode melting pool and deformation of the anode is calculated using the magneto-hydrodynamic (MHD) model with the volume of fraction (VOF) method. All the models are transient 2D axial-rotational symmetric models. The influence of the impaction force of the arc plasma, electromagnetic force, viscosity force, and surface tension of the liquid metal are all considered in the model. The heat flux density injected into the anode and the arc pressure are obtained from the 3D numerical simulation of the high-current vacuum arc using the MHD model, which gives more realistic parameters for the anode simulation. Simulation results show that the depth of the anode melting pool increases with an increase in the arc current. Some droplets sputter out from the anode surface, which is caused by the inertial centrifugal force of the rotational melting pool and strong plasma pressure. Compared with the previous anode melting model without consideration of anode deformation, when the deformation and swirl flow of the anode melting pool are considered, the anode temperature is relatively lower, and just a little more than the melting point of Cu. This is because of liquid droplets sputtering out of the anode surface taking much of the energy away from the anode surface. The

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

    OpenAIRE

    Gangloff, Dorian; Shi, Molu; 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 opti...

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

    International Nuclear Information System (INIS)

    We have investigated the morphology and structure of dolomite MgCa(CO3)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 CO2 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. (paper)

  3. The construction, characterization and use of a low-energy, ultra-high vacuum compatible, metal ion source

    International Nuclear Information System (INIS)

    The design, operation, and use of a low-cost, single grid, electron impact, ultra-high vacuum (UHV) compatible, low-to-medium energy (50-500 eV) ion source capable of operating with medium vapour pressure source material such as Indium is described. (author)

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

    International Nuclear Information System (INIS)

    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−1 (174.8±0.1 (stat.)±0.1 (syst.) nm) and the full width at half maximum of 3328±72 (stat.)±65 (syst.) cm−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

  5. 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.

  6. 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.

  7. Experimental program to study the physical vacuum: high-energy nucleus-nucleus collisions

    International Nuclear Information System (INIS)

    Quarks and gluons exist; they are nearly massless, but it is very hard or even impossible to knock them out of the proton. It is now widely believed that this strange state of affairs is due to the properties of the physical vacuum state as it now exists in our part of the Universe. On this view, the ground state of the vacuum is not that familiar in quantum electrodynamics (QED). That state is basically empty space, perturbed by fluctuations which occasionally give rise to a virtual electron-positron pair. In the quantum chromodynamic (QCD) theory of quarks and gluons, the stronger and more complicated forces give rise to a state which cannot be described as a perturbation on empty space. Instead, the physical vacuum has properties which resemble those of a physical medium. For example, the color field is completely excluded, or at least strongly repelled, from a macroscopic volume of physical vacuum. This effect confines the quarks and gluons which carry color, inside the hadrons. On the scale of hadrons, quantum fluctuations make the phenomena more complex, but a simple picture postulates that the strong color fields inside the hadron create a local volume of space more like the perturbative vacuum state, reverting to the physical vacuum state outside. This concept has been quantitatively expressed by the bag model, with some success. It seems that the physical vacuum has acquired properties reminiscent of Maxwell's ether. At least, so we are asked to believe. Maxwell introduced his ether for plausible reasons, but crucial experimental tests were found, and the theory was found wanting. In this talk, experiments for testing the idea that the physical vacuum is not identical to the perturbative one are discussed

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

    International Nuclear Information System (INIS)

    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. (paper)

  9. TRIBOLOGICAL BEHAVIORS OF PLASMA NITRIDED AISI 316 LN TYPE STAINLESS STEEL IN AIR AND HIGH VACUUM ATMOSPHERE AT ROOM TEMPERATURE

    Directory of Open Access Journals (Sweden)

    A.DEVARAJU

    2010-09-01

    Full Text Available In this work, tribological behaviors of the plasma nitrided AISI 316 LN type austenitic stainless steel specimens (both pins and rings have been analyzed. The experiments have been conducted in high vacuum and in air atmosphere using Vacuum based high temperature Pin-on-disc tribometer. The tribological parameters such as friction coefficient and wear resistance have been analyzed by Origin graphs. The wear mechanisms involved have been identified by recording surface morphology on the wear track and pin surface through scanning electron microscope (SEM and Optical profilometer. The self mating of AISI 316 LN type stainless steel (316LN exhibits strong adhesion between the contact surfaces and severe surface damage both in air and in vacuum atmosphere. But, the self mating of Plasma Nitrided 316LN (CrN/CrN reveals mild wear till the CrN coating peeled off from the pin surface. It has also been proved that Plasma Nitrided (CrN layer on 316 LN ring was wear resistant layer when it issliding against the untreated 316 LN pin in air and high vacuum atmosphere.

  10. Ultra-high vacuum scanning thermal microscopy for nanometer resolution quantitative thermometry.

    Science.gov (United States)

    Kim, Kyeongtae; Jeong, Wonho; Lee, Woochul; Reddy, Pramod

    2012-05-22

    Understanding energy dissipation at the nanoscale requires the ability to probe temperature fields with nanometer resolution. Here, we describe an ultra-high vacuum (UHV)-based scanning thermal microscope (SThM) technique that is capable of quantitatively mapping temperature fields with ∼15 mK temperature resolution and ∼10 nm spatial resolution. In this technique, a custom fabricated atomic force microscope (AFM) cantilever, with a nanoscale Au-Cr thermocouple integrated into the tip of the probe, is used to measure temperature fields of surfaces. Operation in an UHV environment eliminates parasitic heat transport between the tip and the sample enabling quantitative measurement of temperature fields on metal and dielectric surfaces with nanoscale resolution. We demonstrate the capabilities of this technique by directly imaging thermal fields in the vicinity of a 200 nm wide, self-heated, Pt line. Our measurements are in excellent agreement with computational results-unambiguously demonstrating the quantitative capabilities of the technique. UHV-SThM techniques will play an important role in the study of energy dissipation in nanometer-sized electronic and photonic devices and the study of phonon and electron transport at the nanoscale. PMID:22530657

  11. Improved Contacts to MoS2 Transistors by Ultra-High Vacuum Metal Deposition.

    Science.gov (United States)

    English, Chris D; Shine, Gautam; Dorgan, Vincent E; Saraswat, Krishna C; Pop, Eric

    2016-06-01

    The scaling of transistors to sub-10 nm dimensions is strongly limited by their contact resistance (RC). Here we present a systematic study of scaling MoS2 devices and contacts with varying electrode metals and controlled deposition conditions, over a wide range of temperatures (80 to 500 K), carrier densities (10(12) to 10(13) cm(-2)), and contact dimensions (20 to 500 nm). We uncover that Au deposited in ultra-high vacuum (∼10(-9) Torr) yields three times lower RC than under normal conditions, reaching 740 Ω·μm and specific contact resistivity 3 × 10(-7) Ω·cm(2), stable for over four months. Modeling reveals separate RC contributions from the Schottky barrier and the series access resistance, providing key insights on how to further improve scaling of MoS2 contacts and transistor dimensions. The contact transfer length is ∼35 nm at 300 K, which is verified experimentally using devices with 20 nm contacts and 70 nm contact pitch (CP), equivalent to the "14 nm" technology node. PMID:27232636

  12. Distribution and formation of molecularly thin lubricants by thermostatic high vacuum AFM

    International Nuclear Information System (INIS)

    Distribution and formation of molecularly thin lubricants (95% Zdol and 5% X-1P) on CHx carbon surfaces has been studied by thermostatic high vacuum atomic force microscopy (THV-AFM). Results show that Zdol or/and X-1P distribute in island-shaped aggregation independent of topography of CHx surfaces at different temperatures. At 20 deg. C, 10-7 Torr, distribution of X-1P additive can be mapped distinctly without interfering features from Zdol lubes. As temperature decreases, features from Zdol gradually present both in topographic images and in phase images. Measured heights of Zdol islands increase with temperature varying from -20 to -60 deg. C, however, the island diameters do not change significantly. At -60 deg. C and 10-7 Torr, lubricant islands have a typical height of ∼3.5 nm and a typical diameter of ∼100 nm. The area coverage ratio of lubricant islands to CHx surfaces is ∼0.59. To interpret these results, we present a lubricant distribution model involving an initial site-specific adsorption process in the solutions and a long time reorganization process after solvent evaporation

  13. High aspect ratio lead zirconate titanate tube structures: I. Template assisted fabrication - vacuum infiltration method

    Directory of Open Access Journals (Sweden)

    Vladimír Kovaľ

    2012-03-01

    Full Text Available Polycrystalline Pb(Zr0.52Ti0.48O3 (PZT microtubes are fabricated by a vacuum infiltration method. The method is based on repeated infiltration of precursor solution into macroporous silicon (Si templates at a sub-atmospheric pressure. The pyrolyzed PZT tubes of a 2-µm outer diameter, extending to over 30 µm in length were released from the template using a selective isotropic-pulsed XeF2 reactive ion etching of silicon. Free-standing microtubes, partially anchored at the bottom of the Si template, were then crystallized in pure oxygen atmosphere at 750 °C for 2 min using a rapid thermal annealer. The perovskite phase of the final PZT tubes was confirmed by X-ray diffraction (XRD analysis. The XRD spectrum also revealed a small amount of the pyrochlore phase in the structure and signs of possible fluoride contamination caused most likely by the XeF2 etching process. The surface morphology was examined using scanning electron microscopy. It was demonstrated that the whole surface of the pore walls was conformally coated during the repeated infiltration of templates, resulting in straight tubes with closed tips formed on the opposite ends as replicas of the pore bottoms. These high aspect ratio ferroelectric structures are suggested as building units for developing miniaturized electronic devices, such as memory storage (DRAM trenched capacitors, piezoelectric scanners and actuators, and are of fundamental value for the theory of ferroelectricity in systems with low dimensionality.

  14. Effect of irradiation dose on plastic deformation of vacuum hot pressed ultra high molecular weight polyethylene

    International Nuclear Information System (INIS)

    Ultra high molecular weight polyethylene is a type of semi-crystalline polymer which is widely used in artificial joints. Degradation of it's mechanical properties under irradiation is an important aspect for its applications. In this study, molded and ram extruded material were gamma irradiated in vacuum at doses of 50 kGy, 100 kGy and 150 kGy and its uniaxial tensile properties were investigated at room temperature. The results showed that the tensile modulus, true ultimate stress and true ultimate strain were reduced as the dose increased. There was no significant difference of the true yield strain between non-crosslinked and crosslinked material, but the true yield stress of non-crosslinked material was significantly higher than the crosslinked material. The curvature of the true stress-true strain curve after yielding did not exhibit a significant relationship as a function of dose. However, both molded and ram extruded material showed a significant exponent relationship with dose.

  15. Mechanical design, development, and installation of ultra high vacuum compatible beam position indicators for insertion devices in Indus-2

    International Nuclear Information System (INIS)

    Recently, two insertion devices (undulators) have been installed in long straight sections LS-2 and LS-3 of Indus-2. For precise monitoring of electron beam position at the entry and exit of these insertion devices, 17 mm vertical low gap type ultra high vacuum (UHV) compatible insertion device beam position indicators (IDBPls) have been designed, developed, and installed by Beam Diagnostics Section. The water cooled RF shielded bellows have also been designed, developed, and integrated in IDBPI assembly by Ultra High Vacuum Technology Section. The IDBPI has 17 mm (V) x 81 mm (H) internal race track profile aperture same as of vacuum chamber of insertion device. It incorporates four numbers of electrode subassemblies directly welded (by TIG) to its vacuum chamber. The button diameter is 9 mm. The horizontal separation between buttons is 12 mm. The IDBPI assemblies have been installed in Indus-2 ring and are in operation since Jan 2015. The mechanical design, development procedure and initial results have been described in this paper

  16. Influence of the cold cathode material on the operating mode of the pulse high-current vacuum diode in a microsecond range

    International Nuclear Information System (INIS)

    The present work is aimed at the description of experimental results on the drop fraction of high-power electrical vacuum discharge and analysis of processes,which take place in cold cathodes working in microsecond range of pulses,and also on the influence of the material of a cold cathode on the operating mode of the pulse high-current vacuum diode

  17. IFSMTF experiences and conclusions regarding the use of Kapton insulated, high-voltage cable in a vacuum/cryogenic environment

    International Nuclear Information System (INIS)

    This paper describes the experiences of the International Fusion Superconducting Magnet Test Facility (IFSMTF), formerly called the Large Coil Test Facility, with regard to the use of Kapton insulated cable for high-voltage instrumentation within the IFSMTF vacuum vessel. Initial high-potential tests performed on the General Dynamics electrical system were disappointing and led to a general review and subsequent change of the philosophy and technology associated with the use of Kapton insulated cable

  18. 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.

  19. 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. PMID:22380156

  20. Ultra-high-vacuum tight transition joints of titanium-stainless steel produced by explosive tube to tube welding

    International Nuclear Information System (INIS)

    The parameters for explosive welding of Stainless Steel to Titanium were determined with the objective to avoid intermetallic compounds and tubular needles at the interface. The optimum parameters were applied for the production of tubular transition joints between Titanium and stainless steel for ultra high vacuum applications. Prototypes were examined mechanically and by metallographic methods and tested under ultra high varuum conditions. An extraordinary mechanical strength of the connection was found, and, in contrary to transition joints, produced by other means, not a single leak occurred in joints fabricated by concentric explosive cladding. Transition joints of the described type were used in laboratories and in the ultra-high-vacuum system of the ISR. (orig.)

  1. Proceedings of the 5th meeting on ultra high vacuum techniques for accelerators and storage rings

    International Nuclear Information System (INIS)

    This is the proceedings of the 5th meeting on UHV Techniques for Accelerators and Storage Rings held at KEK, March 26-27, 1984. More than 110 vacuum scientists attended the meeting, and 23 reports were presented. Main subjects were, of course, concerning with the vacuum systems for large accelerators and plasma devices under planning or construction in Japan. At the same time, many reports on the general problems of vacumm science were also presented. The subjects of these reports were outgassing phenomenon, surface problems, new type UHV pumps and others. (author)

  2. High power Nd:YAG laser welding in manufacturing of vacuum vessel of fusion reactor

    International Nuclear Information System (INIS)

    Laser welding has shown many advantages over traditional welding methods in numerous applications. The advantages are mainly based on very precise and powerful heat source of laser light, which change the phenomena of welding process when compared with traditional welding methods. According to the phenomena of the laser welding, penetration is deeper and thus welding speed is higher. Because of the precise power source and high-welding speed, the heat input to the workpiece is small and distortions are reduced. Also, the shape of laser weld is less critical for distortions than traditional welds. For welding thick sections, the usability of lasers is not so practical than with thin sheets, because with power levels of present Nd:YAG lasers depth of penetration is limited up to about 10 mm by single-pass welding. One way to overcome this limitation is to use multi-pass laser welding, in which narrow gap and filler wire is applied. By this process, thick sections can be welded with smaller heat input and then smaller distortions and the process seems to be very effective comparing 'traditional' welding methods, not only according to the narrower gap. Another way to increase penetration and fill the groove is by using the so-called hybrid process, in which laser and GMAW (gas metal arc welding) are combined. In this paper, 20-mm thick austenitic stainless steel was welded using narrow gap configuration with a multi-pass technique. Two welding procedures were used: Nd:YAG laser welding with filler wire and with addition of GMAW, the hybrid process. In the welding experiments, it was noticed that both processes are feasible for welding thicker sections with good quality and with minimal distortions. Thus, these processes should be considered when the evaluation of the welding process is done for joining vacuum vessel sectors of ITER

  3. High power Nd:YAG laser welding in manufacturing of vacuum vessel of fusion reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jokinen, Tommi E-mail: tommi.jokinen@vtt.fi; Kujanpaeae, Veli E-mail: veli.kujanpaa@lut.fi

    2003-09-01

    Laser welding has shown many advantages over traditional welding methods in numerous applications. The advantages are mainly based on very precise and powerful heat source of laser light, which change the phenomena of welding process when compared with traditional welding methods. According to the phenomena of the laser welding, penetration is deeper and thus welding speed is higher. Because of the precise power source and high-welding speed, the heat input to the workpiece is small and distortions are reduced. Also, the shape of laser weld is less critical for distortions than traditional welds. For welding thick sections, the usability of lasers is not so practical than with thin sheets, because with power levels of present Nd:YAG lasers depth of penetration is limited up to about 10 mm by single-pass welding. One way to overcome this limitation is to use multi-pass laser welding, in which narrow gap and filler wire is applied. By this process, thick sections can be welded with smaller heat input and then smaller distortions and the process seems to be very effective comparing 'traditional' welding methods, not only according to the narrower gap. Another way to increase penetration and fill the groove is by using the so-called hybrid process, in which laser and GMAW (gas metal arc welding) are combined. In this paper, 20-mm thick austenitic stainless steel was welded using narrow gap configuration with a multi-pass technique. Two welding procedures were used: Nd:YAG laser welding with filler wire and with addition of GMAW, the hybrid process. In the welding experiments, it was noticed that both processes are feasible for welding thicker sections with good quality and with minimal distortions. Thus, these processes should be considered when the evaluation of the welding process is done for joining vacuum vessel sectors of ITER.

  4. 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.

  5. State of the art in applied high-current superconductivity

    International Nuclear Information System (INIS)

    The report is aimed at describing the state of the works in the applied high-current superconductivity (AHS). The helium and nitrogen temperature levels are considered. The 2001 and 2003 comparative data on the belt superconductors on the Bi-2223/Ag basis are presented. The performance characteristics of the operating power transmission superconducting lines and the tested and designed HTSC transformers are also presented. The scheme and principles of operation of the SC current limiter with a saturated yoke is presented as well

  6. The Effect of the Time Management Art on Academic Achievement among High School Students in Jordan

    Science.gov (United States)

    Al-Zoubi, Maysoon

    2016-01-01

    This study aimed at recognizing the effect of the Time Management Art on academic achievement among high school students in the Hashemite Kingdom of Jordan. The researcher employed the descriptive-analytic research to achieve the purpose of the study where he chose a sample of (2000) high school female and male students as respondents to the…

  7. A study of the high vacuum engineering for the accelerator tube construction has performed

    International Nuclear Information System (INIS)

    Failure of the accelerator tube vacuum systems due to construction and physical chemistry aspect are reported in this study. The problem solving are presented in this paper, where the results of this engineering concepts are met with the requirement of the technical specifications. (author)

  8. A 10 mK scanning tunneling microscope operating in ultra high vacuum and high magnetic fields.

    Science.gov (United States)

    Assig, Maximilian; Etzkorn, Markus; Enders, Axel; Stiepany, Wolfgang; Ast, Christian R; Kern, Klaus

    2013-03-01

    We present design and performance of a scanning tunneling microscope (STM) that operates at temperatures down to 10 mK providing ultimate energy resolution on the atomic scale. The STM is attached to a dilution refrigerator with direct access to an ultra high vacuum chamber allowing in situ sample preparation. High magnetic fields of up to 14 T perpendicular and up to 0.5 T parallel to the sample surface can be applied. Temperature sensors mounted directly at the tip and sample position verified the base temperature within a small error margin. Using a superconducting Al tip and a metallic Cu(111) sample, we determined an effective temperature of 38 ± 1 mK from the thermal broadening observed in the tunneling spectra. This results in an upper limit for the energy resolution of ΔE = 3.5 kBT = 11.4 ± 0.3 μeV. The stability between tip and sample is 4 pm at a temperature of 15 mK as demonstrated by topography measurements on a Cu(111) surface. PMID:23556826

  9. RF properties at 6 GHz of ultra-high vacuum cathodic arc films up to 450 oersted

    International Nuclear Information System (INIS)

    Several films of niobium were deposited on copper plates via the ultra-high vacuum cathodic arc (UHVCA) deposition method as described by R. Russo et al. [R. Russo et al., Supercond. Sci. Tech. 18 (2005) L41; R. Russo et al., J. Appl. Phys., submitted for publication]. We attached these end plates to a 6 GHz cavity operating in the TE011 mode for characterizing the film quality by measuring the Q versus surface magnetic field

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

    OpenAIRE

    Verma, P.; S Gautam; Pal, S.; Kumar, P.; Chaturvedi, P; J.S.B.S. Rawat; P. K. Chaudhary; Dr. Harsh; Basu, P K; P. K. Bhatanagar

    2008-01-01

    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 he...

  11. High temperature fission chambers. State-of-the-art

    International Nuclear Information System (INIS)

    In the control and the surveillance of fast breeder reactors, high temperature fission chambers able to operate in extremes of temperature and gamma dose perform two essential functions: in-vessel integrated neutronic control; clad failure detection by integrated detectors. In addition, they can be used for example to: measure the weight of the control rods; monitor the insertion of new sub assemblies (SAs) and withdrawal of irradiated SAs; eventually monitor the neutron flux in Boiling Water Reactors (BWR). Since 1970, a major research development and qualification programme has been undertaken in France. This programme has resulted in the development of: dedicated manufacturing processes for fission chambers to cope with the specific conditions in fast breeder reactors; a complete range of detectors to cover all other possible applications. This paper reviews: the detectors in their dedicated applications; the main problems encountered, studies made and solutions found; the detector qualification status; the performance of the detectors in the French fast breeder reactors. (authors)

  12. Influence of vacuum anealling in mechanical properties of high pure polycrystalline niobium with and without neutronic irradiation

    International Nuclear Information System (INIS)

    Electron been melted Niobium specimens, 96% reduction in area by rolling were annealed at 11500C for 2 hours in two kinds of vacuum atmospheres, static and dynamic vacuum. In the treatment in static vacuum the specimens are scaled under vacuum in quartz capsules. In dynamic vacuum the specimens are treated in a continuum operation vacuum system. Both vacuum are better than 10-5 torr. Some of these specimens were irradiated with fast neutrons (E > = 0,1 MeV) at 1400C to a fluence of 1.3 x 1018 n/cm2. The mechanical properties of 5 lots were compared (a) the original cold-rolled state (b) cold-rolled annealed in static vacuum (b') cold-rolled annealed in static vacuum and irradiated, (c) cold-rolled, annealed in dynamic vacuum (c') cold-rolled, annealed in dynamic vacuum and irradiated. Tensile tests were done in sub-size specimens. (Author)

  13. State of the art of high energy photon treatment planning

    International Nuclear Information System (INIS)

    A virtual revolution in computer capability has occurred in the last few years, based largely on rapidly decreasing costs and increasing reliability of digital memory and mass-storage capability. These developments have now made it possible to consider the application of both computer and display technologies to a much broader range of problems in radiation therapy including dose computation, therapy planning and treatment verification. Various similar methods of three-dimensional dose computations in heterogeneous media capable of 2-3% accuracy are likely to be available, but significant work still remains especially for high energy X-rays where electron transport, and possibly pair production, needs to be considered. Innovative display and planning techniques are emerging and show great promise for the future. No doubt these advances will lead to substantially improved treatment planning systems in the next few years. However, it must be emphasized that for many of these applications a tremendous software and hardware development effort is required. Yet it is not clear whether the investments and efforts for improved capabilities and accuracies are warranted with respect to clinical outcome. The question must be addressed for the advancement in the practice of radiotherapy

  14. Large area scanning probe microscope in ultra-high vacuum demonstrated for electrostatic force measurements on high-voltage devices

    Directory of Open Access Journals (Sweden)

    Urs Gysin

    2015-12-01

    Full Text Available Background: The resolution in electrostatic force microscopy (EFM, a descendant of atomic force microscopy (AFM, has reached nanometre dimensions, necessary to investigate integrated circuits in modern electronic devices. However, the characterization of conducting or semiconducting power devices with EFM methods requires an accurate and reliable technique from the nanometre up to the micrometre scale. For high force sensitivity it is indispensable to operate the microscope under high to ultra-high vacuum (UHV conditions to suppress viscous damping of the sensor. Furthermore, UHV environment allows for the analysis of clean surfaces under controlled environmental conditions. Because of these requirements we built a large area scanning probe microscope operating under UHV conditions at room temperature allowing to perform various electrical measurements, such as Kelvin probe force microscopy, scanning capacitance force microscopy, scanning spreading resistance microscopy, and also electrostatic force microscopy at higher harmonics. The instrument incorporates beside a standard beam deflection detection system a closed loop scanner with a scan range of 100 μm in lateral and 25 μm in vertical direction as well as an additional fibre optics. This enables the illumination of the tip–sample interface for optically excited measurements such as local surface photo voltage detection.Results: We present Kelvin probe force microscopy (KPFM measurements before and after sputtering of a copper alloy with chromium grains used as electrical contact surface in ultra-high power switches. In addition, we discuss KPFM measurements on cross sections of cleaved silicon carbide structures: a calibration layer sample and a power rectifier. To demonstrate the benefit of surface photo voltage measurements, we analysed the contact potential difference of a silicon carbide p/n-junction under illumination.

  15. A new high-gain vacuum photomultiplier based upon the amplification of a Geiger-mode p-n junction

    International Nuclear Information System (INIS)

    The future astroparticle experiments will study both energetic phenomena and extremely rare events from astrophysical sources. Since most of these families of experiments are carried out by using scintillation phenomena, Cherenkov or fluorescence radiation, the development of photosensitive detectors seems to be the right way to increase the experimental sensitivity. We therefore propose an innovative design for a modern, high gain, silicon-based Vacuum Silicon Photomultiplier Tube (VSiPMT), which combines three fully established and well-understood technologies: the manufacture of hemispherical vacuum tubes with the possibility of very large active areas, the photocathode glass deposition and the recent Geiger-mode avalanche silicon photodiode (G-APD) for which a mass production is today available. This new design, based on G-APD as the electron multiplier, allows overcoming the limits of the classical PMT dynode chain

  16. 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.

  17. Re-Cr-Ni high-temperature resistant coatings on Cu substrates prepared by thermionic vacuum arc (TVA) method

    International Nuclear Information System (INIS)

    Re-Cr-Ni composite metallic films were prepared using an original plasma deposition method developed at INFLPR, Bucharest, called thermionic vacuum arc (TVA). The method is based on the evaporation of a metal followed by ignition of a plasma in the vapours. These three-component films/alloy films were deposited using three simultaneous TVA plasma sources in the same vacuum chamber. Surface corrosion at temperatures up to 1000 deg. C was found not to take place in these Re-Cr-Ni alloy films as shown by thermogravimetric analysis. The current results demonstrate that the TVA method is a promising candidate tool for the synthesis of multiple compound films. Films of uniform and controlled composition can be simultaneously obtained using this method. Moreover, high melting point metals can be involved in these superalloy films, thus leading to applications in extremely hot conditions such as turbine blades and aircraft parts. (fast track communication)

  18. Purification by high vacuum fusion and progressive solidification of uranium from electrolytic origin

    International Nuclear Information System (INIS)

    Within the general framework of research on uranium purification by zone melting, an attempt was made to determine the degree of purification which could be obtained by a simple gradual solidification of a normal nuclear-pure uranium paying close attention to the rate and direction of solidification. This uranium of intermediate purity would provide a starting material more suited to the first purification which is a vertical zone-melting process, so-called 'floating'. For this purpose, ingots of electrolytic uranium were melted under vacuum (2 to 5 x 10-6 mm) in a long crucible after a slow rise in temperature to eliminate as much as possible the gases and volatiles impurities. This degassing and impurities volatilisation are completed by maintaining both at a high temperature for a considerable time. The beth is then made to solidify from the one an in the other the crucible by slowly moving the solid-liquid interface at a constant rate so as to obtain an impurity distribution according to the laws established by PFANN. Various experimental methods have made it possible to show that the metal which solidifies first is much purer than that at the other end of the ingot. The degree of purification of the metal at the beginning of the ingot has been evaluated either quantitatively by measuring the ratio of the electrical resistivities at room temperature and at the liquid nitrogen temperature, or qualitatively by an examination of the micrographic structure and by a study of the recrystallisation of the metal. On the one hand the purified metal re-crystallises during iso-chromic annealings carried out at increasing temperatures, at a temperature much lower than the initial metal or than the end of the ingot. The passage from the cold-worked state to the recrystallised state is followed by micro-hardness measurements. On the other end, only is the purified metal, strongly cold-worked by unidirectional melting, is the phenomenon of 'dissociative growth' of the grain

  19. Ultra high vacuum fracture and transfer device for AES analysis of irradiated austenitic stainless steel

    International Nuclear Information System (INIS)

    An ultrahigh vacuum fracture and transfer device for analysis of irradiated and non-irradiated SS 316 fuel cladding is described. Mechanical property tests used to study the behavior of cladding during reactor transient over-power conditions are reported. The stress vs temperature curves show minimal differences between unirradiated cladding and unfueled cladding. The fueled cladding fails at a lower temperature. All fueled specimens failed in an intergranular mode

  20. Design and fabrication of a high vacuum box, to be used in one ion polarization system

    International Nuclear Information System (INIS)

    The paper discusses in considerable detail some of the concepts associated with vacuum systems as well as some of the factors which enter into the design of components and units employed in such systems. One of the aims pursued is to establish national technology suited to designing and manufacturing needs arising in connection with problems like the one described, with training, as appropriate, for the personnel involved in the entire development process. (author)

  1. Junior High Curriculum Guide to Language Arts of the Mehlville School District.

    Science.gov (United States)

    Mehlville R-9 School District, St. Louis, MO.

    Based on the latest research and theories, this junior high school curriculum guide was prepared for teachers of language arts. Following a statement of the philosophy of the program, teaching objectives are stated for writing, literature, and related skill areas. Other sections include a scope and sequence chart, evaluation and testing…

  2. ?Ffects of Using of Contemporary Art in High Education on Students Metacognitive Awareness

    Science.gov (United States)

    Delibaltova, Vasya

    2016-01-01

    The aim of this study was to determine the effects of the use of contemporary art in High Education on Students' Metacognitive Awareness from students' point of view after their involvement in specially designed activities. The learning context was created under the main thesis that metacognitive development can be supported by the creation of…

  3. 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

  4. 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.

  5. Preventing and reversing vacuum-induced optical losses in high-finesse tantalum (V) oxide mirror coatings

    Science.gov (United States)

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

    2015-07-01

    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.

  6. 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.

  7. Vacuum Virtues

    Science.gov (United States)

    Rathey, Allen

    2007-01-01

    Upright vacuums, like cars, vary in quality, features and performance. Like automobiles, some uprights are reliable, others may be problematic, and some become a problem as a result of neglect or improper use. So, how do education institutions make an informed choice and, having done so, ensure that an upright vacuum goes the distance? In this…

  8. Design and performance of an ultra-high vacuum scanning tunneling microscope operating at dilution refrigerator temperatures and high magnetic fields

    OpenAIRE

    Misra, Shashank; Zhou, Brian B.; 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 loca...

  9. 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. PMID:27324623

  10. A Large High Vacuum Reaction Chamber for Nuclear Physics Research at VECC, Kolkata

    Science.gov (United States)

    Kundu, S.; Bhattacharya, S.; Meena, J. K.; Ghosh, T. K.; Bhattacharjee, T.; Mukhopadhyay, P.; Bhattacharya, C.; Rana, T. K.; Banerjee, K.; Mukherjee, G.; Banerjee, S. R.; Bandyopadhyay, D. L.; Ahammed, M.; Bhattacharya, P.

    2012-11-01

    A large, segmented, horizontal axis, reaction chamber (SHARC) has recently been fabricated, installed and integrated with the beam line in the VECC superconducting cyclotron (SCC) experimental area. It is a cylindrical, three segment, stainless steel chamber of length 2.2 m, diameter 1 m. Two pairs of parallel rails have been provided internally for placement of the target assembly and detector systems within the chamber. The whole target assembly can be placed anywhere on the rail to facilitate optimum flight path. The nominal vacuum of ~1×10-7 mbar has been obtained in ~8 hrs by means of two turbo molecular (1000 l/s) and two cryo pumps (2500 l/s) backed by mechanical pumps. The whole vacuum system as well as the target positioning (vertical and rotational movements) operations are fully automated with manual override option; both are monitored and controlled locally as well as remotely through the local and remote control units providing real time status display.

  11. A Large High Vacuum Reaction Chamber for Nuclear Physics Research at VECC, Kolkata

    International Nuclear Information System (INIS)

    A large, segmented, horizontal axis, reaction chamber (SHARC) has recently been fabricated, installed and integrated with the beam line in the VECC superconducting cyclotron (SCC) experimental area. It is a cylindrical, three segment, stainless steel chamber of length 2.2 m, diameter 1 m. Two pairs of parallel rails have been provided internally for placement of the target assembly and detector systems within the chamber. The whole target assembly can be placed anywhere on the rail to facilitate optimum flight path. The nominal vacuum of ∼1×10−7 mbar has been obtained in ∼8 hrs by means of two turbo molecular (1000 l/s) and two cryo pumps (2500 l/s) backed by mechanical pumps. The whole vacuum system as well as the target positioning (vertical and rotational movements) operations are fully automated with manual override option; both are monitored and controlled locally as well as remotely through the local and remote control units providing real time status display.

  12. Measurement of thermal conductivity of Bi2Te3 nanowire using high-vacuum scanning thermal wave microscopy

    Science.gov (United States)

    Park, Kyungbae; Hwang, Gwangseok; Kim, Hayeong; Kim, Jungwon; Kim, Woochul; Kim, Sungjin; Kwon, Ohmyoung

    2016-02-01

    With the increasing application of nanomaterials in the development of high-efficiency thermoelectric energy conversion materials and electronic devices, the measurement of the intrinsic thermal conductivity of nanomaterials in the form of nanowires and nanofilms has become very important. However, the current widely used methods for measuring thermal conductivity have difficulties in eliminating the influence of interfacial thermal resistance (ITR) during the measurement. In this study, by using high-vacuum scanning thermal wave microscopy (HV-STWM), we propose a quantitative method for measuring the thermal conductivity of nanomaterials. By measuring the local phase lag of high-frequency (>10 kHz) thermal waves passing through a nanomaterial in a high-vacuum environment, HV-STWM eliminates the measurement errors due to ITR and the distortion due to heat transfer through air. By using HV-STWM, we measure the thermal conductivity of a Bi2Te3 nanowire. Because HV-STWM is quantitatively accurate and its specimen preparation is easier than in the thermal bridge method, we believe that HV-STWM will be widely used for measuring the thermal properties of various types of nanomaterials.

  13. Cu-TBPP and PTCDA molecules on insulating surfaces studied by ultra-high-vacuum non-contact AFM

    OpenAIRE

    Nony, Laurent; Bennewitz, Roland; Pfeiffer, Oliver; Gnecco, Enrico; Baratoff, Alexis; Meyer, Ernst; Eguchi, Toyoaki; Gourdon, André; Joachim, Chrisitan

    2004-01-01

    The adsorption of two kinds of porphyrin (Cu-TBPP) and perylene (PTCDA) derived organic molecules deposited on KBr and Al2O3 surfaces has been studied by non-contact force microscopy in ultra-high vacuum, our goal being the assembly of ordered molecular arrangements on insulating surfaces at room temperature. On a Cu(100) surface, well ordered islands of Cu-TBPP molecules were successfully imaged. On KBr and Al2O3 surfaces, it was found that the same molecules aggregate in small clusters at s...

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

    OpenAIRE

    Amaro, P.; Szabo, C. I.; Schlesser, S.; Gumberidze, Alexandre; G. Kessler Jr, Ernest; Henins, Albert; Le Bigot, E.-O.; Trassinelli, Martino; 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....

  15. 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.

  16. 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

  17. The use of high vacuum soil vapor extraction to improve contaminant recovery from ground water zones of low transmissivity

    International Nuclear Information System (INIS)

    This study examines the potential for enhancing hydrocarbon contaminant mass recovery from ground water using high vacuum soil vapor extraction (SVE). The effectiveness of this form of remediation is compared with the effectiveness of conventional pump-and-treat. This study focuses on the performance of a high vacuum SVE system at two ground water monitoring wells (MW-17 and MW-65b) at a site in Santa Barbara, California, US. The site is a highly characterized site with vadose zone and ground water petroleum hydrocarbon contamination (gasoline). The ground water wells are located beyond a defined area of vadose zone soil contamination. Ground water hydrocarbon contamination [light non-aqueous phase liquid (LNAPL) and dissolved phase] is present at each of the wells. the ground water wells have been part of a low-flow, pump-and-treat, ground water treatment system (GWTS) since August, 1986. The low transmissivity of the aquifer sediments prevent flow rates above approximately 0.02 gpm (0.01 l/min) per well

  18. In situ preparation of biomimetic thin films and their surface-shielding effect for organisms in high vacuum.

    Directory of Open Access Journals (Sweden)

    Hiroshi Suzuki

    Full Text Available Self-standing biocompatible films have yet to be prepared by physical or chemical vapor deposition assisted by plasma polymerization because gaseous monomers have thus far been used to create only polymer membranes. Using a nongaseous monomer, we previously found a simple fabrication method for a free-standing thin film prepared from solution by plasma polymerization, and a nano-suit made by polyoxyethylene (20 sorbitan monolaurate can render multicellular organisms highly tolerant to high vacuum. Here we report thin films prepared by plasma polymerization from various monomer solutions. The films had a flat surface at the irradiated site and were similar to films produced by vapor deposition of gaseous monomers. However, they also exhibited unique characteristics, such as a pinhole-free surface, transparency, solvent stability, flexibility, and a unique out-of-plane molecular density gradient from the irradiated to the unirradiated surface of the film. Additionally, covering mosquito larvae with the films protected the shape of the organism and kept them alive under the high vacuum conditions in a field emission-scanning electron microscope. Our method will be useful for numerous applications, particularly in the biological sciences.

  19. A vacuum flash-assisted solution process for high-efficiency large-area perovskite solar cells.

    Science.gov (United States)

    Li, Xiong; Bi, Dongqin; Yi, Chenyi; Décoppet, Jean-David; Luo, Jingshan; Zakeeruddin, Shaik Mohammed; Hagfeldt, Anders; Grätzel, Michael

    2016-07-01

    Metal halide perovskite solar cells (PSCs) currently attract enormous research interest because of their high solar-to-electric power conversion efficiency (PCE) and low fabrication costs, but their practical development is hampered by difficulties in achieving high performance with large-size devices. We devised a simple vacuum flash-assisted solution processing method to obtain shiny, smooth, crystalline perovskite films of high electronic quality over large areas. This enabled us to fabricate solar cells with an aperture area exceeding 1 square centimeter, a maximum efficiency of 20.5%, and a certified PCE of 19.6%. By contrast, the best certified PCE to date is 15.6% for PSCs of similar size. We demonstrate that the reproducibility of the method is excellent and that the cells show virtually no hysteresis. Our approach enables the realization of highly efficient large-area PSCs for practical deployment. PMID:27284168

  20. A vacuum flash–assisted solution process for high-efficiency large-area perovskite solar cells

    Science.gov (United States)

    Li, Xiong; Bi, Dongqin; Yi, Chenyi; Décoppet, Jean-David; Luo, Jingshan; Zakeeruddin, Shaik Mohammed; Hagfeldt, Anders; Grätzel, Michael

    2016-07-01

    Metal halide perovskite solar cells (PSCs) currently attract enormous research interest because of their high solar-to-electric power conversion efficiency (PCE) and low fabrication costs, but their practical development is hampered by difficulties in achieving high performance with large-size devices. We devised a simple vacuum flash–assisted solution processing method to obtain shiny, smooth, crystalline perovskite films of high electronic quality over large areas. This enabled us to fabricate solar cells with an aperture area exceeding 1 square centimeter, a maximum efficiency of 20.5%, and a certified PCE of 19.6%. By contrast, the best certified PCE to date is 15.6% for PSCs of similar size. We demonstrate that the reproducibility of the method is excellent and that the cells show virtually no hysteresis. Our approach enables the realization of highly efficient large-area PSCs for practical deployment.

  1. High current RF shield for PEP-II vacuum system expansion joint

    International Nuclear Information System (INIS)

    A novel RF shield was developed for the circular expansion joint used throughout the PEP-II vacuum system straight sections. Existing RF shield designs, used in accelerators/storage rings throughout the world, have been the source of many failures at beam currents much smaller than the 3 amps planned for PEP-II. This RF shield uses a unique spring-loaded finger mechanism to maintain proper electrical contact across the joint, accommodate 1.5 mm transverse and 32 mm longitudinal excursions, while minimizing geometry-driven trapped-mode RF heating at GHz frequencies. Alumina-dispersed, copper alloy fingers are used to maintain desired mechanical properties at higher temperatures instead of the more commonly used beryllium-copper alloys. A prototype expansion joint was assembled, mechanically tested, and subjected to 200% of the expected operational RF load. This RF shield design can be easily adapted to non-circular geometries

  2. High-temperature fatigue behavior of unirradiated V-15Cr-5Ti tested in vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Liu, K.C.

    1981-01-01

    Limited results of in-vacuum fatigue tests are presented for unirradiated V-15Cr-5Ti tested at room temperature, 550, and 650/sup 0/C, respectively. The test data were analyzed using a power law equation to correlate the total strain range and cycles to failure. Comparison with data for 20% cold-worked Type 316 stainless steel tested at 550/sup 0/C shows that on the basis of strain range the vanadium alloy is about the same as the stainless steel below 10,000 cycles to failure but becomes superior above the point. The general data trend further suggests that endurance limits may exist at strain ranges of approximately 0.7 and 0.6% at 550 and 650/sup 0/C, respectively.

  3. 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.

  4. 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.

  5. Cultivating Common Ground: Integrating standards-based visual arts, math and literacy in high-poverty urban classrooms

    OpenAIRE

    Cunnington, Marisol; Kantrowitz, Andrea; Harnett, Susanne; Hill-Ries, Aline

    2014-01-01

    The Framing Student Success: Connecting Rigorous Visual Arts, Math and Literacy Learning experimental demonstration project was designed to develop and test an instructional program integrating high-quality, standards-based instruction in the visual arts, math, and literacy. Developed and implemented by arts-in-education organization Studio in a School (STUDIO), in partnership with the New York City Department of Education, the Framing Student Success curriculum was designed by e...

  6. A state of the art review of vitrification of high level waste in Europe

    International Nuclear Information System (INIS)

    This paper gives a review of the state-of-the-art of the development and demonstration of vitrification processes for high level radioactive waste solutions on an industrial scale in four European countries (France, United Kingdom, Federal Republic of Germany and Belgium). Historical development, experiences and operations present status and future plans are presented. Three of the processes which seem to be of major importance are described (AVM-France, HARVEST-United Kingdom, PAMELA Germany/Belgium). (author)

  7. Conceptualizing entrepreneurship in music: A project-based view of entrepreneurship in high art music performance

    OpenAIRE

    Crookes, Deborah

    2008-01-01

    The concept of entrepreneurship in research and society has been firmly rooted in the realm of economics and business. This narrow focus excludes a large number of entrepreneurial acts that occur outside of economic contexts. The discipline of high art music performance is rich with innovative acts that challenge the boundaries of conventional practices. However, these acts largely go unnoticed because of the strength of the bond between entrepreneurship and economics. In this research paper,...

  8. Cosmic vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Chernin, Artur D [P.K. Shternberg State Astronomical Institute at the M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

    2001-11-30

    Recent observational studies of distant supernovae have suggested the existence of cosmic vacuum whose energy density exceeds the total density of all the other energy components in the Universe. The vacuum produces the field of antigravity that causes the cosmological expansion to accelerate. It is this accelerated expansion that has been discovered in the observations. The discovery of cosmic vacuum radically changes our current understanding of the present state of the Universe. It also poses new challenges to both cosmology and fundamental physics. Why is the density of vacuum what it is? Why do the densities of the cosmic energy components differ in exact value but agree in order of magnitude? On the other hand, the discovery made at large cosmological distances of hundreds and thousands Mpc provides new insights into the dynamics of the nearby Universe, the motions of galaxies in the local volume of 10 - 20 Mpc where the cosmological expansion was originally discovered. (reviews of topical problems)

  9. Cosmic vacuum

    International Nuclear Information System (INIS)

    Recent observational studies of distant supernovae have suggested the existence of cosmic vacuum whose energy density exceeds the total density of all the other energy components in the Universe. The vacuum produces the field of antigravity that causes the cosmological expansion to accelerate. It is this accelerated expansion that has been discovered in the observations. The discovery of cosmic vacuum radically changes our current understanding of the present state of the Universe. It also poses new challenges to both cosmology and fundamental physics. Why is the density of vacuum what it is? Why do the densities of the cosmic energy components differ in exact value but agree in order of magnitude? On the other hand, the discovery made at large cosmological distances of hundreds and thousands Mpc provides new insights into the dynamics of the nearby Universe, the motions of galaxies in the local volume of 10 - 20 Mpc where the cosmological expansion was originally discovered. (reviews of topical problems)

  10. Vacuum chamber

    International Nuclear Information System (INIS)

    A detailed description is given of the vacuum chamber of the so-called experimental equipment DEMAS (double-arm-time-of-flight spectrometer) at the heavy ion accelerator U-400 at the JINR-Dubna. (author)

  11. Vacuum properties of high quality value tuning fork in high magnetic field up to 8 Tesla and at mK temperatures

    OpenAIRE

    Clovecko, M.; Kupka, M.; Skyba, P.; Vavrek, F.

    2014-01-01

    Tuning forks are very popular experimental tools widely applied in low and ultra low temperature physics as mechanical resonators and cantilevers in the study of quantum liquids, STM and AFM techniques, etc. As an added benefit, these forks being cooled, have very high Q-value, typically $10^6$ and their properties seems to be magnetic field independent. We present preliminary vacuum measurements of a commercial tuning fork oscillating at frequency 32~kHz conducted in magnetic fields up to 8~...

  12. Vacuum II

    CERN Document Server

    Franchetti, G

    2013-01-01

    This paper continues the presentation of pumps begun in ‘Vacuum I’. The main topic here is gauges and partial-pressure measurements. Starting from the kinetics of gases, the various strategies for measuring vacuum pressures are presented at an introductory level, with some reference to hardware devices. Partial-pressure measurement techniques are introduced, showing that the principles of ion selection have a direct similarity to particle dynamics in accelerators.

  13. 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.

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

    International Nuclear Information System (INIS)

    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. (paper)

  15. New trends in oil free vacuum generation equipment

    Directory of Open Access Journals (Sweden)

    Vasiliev Yu. K.

    2010-03-01

    Full Text Available Main modern trends of vacuum technology and vacuum equipment market such as fore-vacuum and high-vacuum pumps, analytical devices and vacuum components are shown. Amount of different regional markets is also reviewed by main world vacuum equipment suppliers turnover.

  16. New trends in oil free vacuum generation equipment

    OpenAIRE

    Vasiliev Yu. K.; Nesterov S. B.; Vasilieva T. S.

    2010-01-01

    Main modern trends of vacuum technology and vacuum equipment market such as fore-vacuum and high-vacuum pumps, analytical devices and vacuum components are shown. Amount of different regional markets is also reviewed by main world vacuum equipment suppliers turnover.

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

    International Nuclear Information System (INIS)

    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

  18. Development of ultra high vacuum gate valves with polyimide resin plate seal and measurement of their performance

    International Nuclear Information System (INIS)

    Polyimide resin was used for manufacturing ultra high vacuum gate valves. First of all, the gas permeability of the resin was measured. The test gases were helium and argon, and the sample temperature was up to 250 degree C. The permeability constant for helium was about 1 x 10-8 Torr. l.mm/s.Cm_2. atm at room temperature, and 1.5 x 10-6 Torr.l.mm/s.Cm_2. atm at 250 degree C. The outgas from the polyimide resin was also measured, and was less than 1/10 of that from viton. The composition of residual gases of the polyimide showed good features at 300 degree C. Since the helium leak rate from polyimide gate valves depends on the applied stress on the resin, and the required accuracy of the surface finishing is severe, careful treatment is necessary for the manufacturing. The difference of leak rate was seen between the use below 250 degree C and above 300 degree C. Electrically insulated gaskets can be manufactured, and their performance in vacuum was satisfactory. (Kato, T.)

  19. A diamond-based scanning probe spin sensor operating at low temperature in ultra-high vacuum

    International Nuclear Information System (INIS)

    We present the design and performance of an ultra-high vacuum (UHV) low temperature scanning probe microscope employing the nitrogen-vacancy color center in diamond as an ultrasensitive magnetic field sensor. Using this center as an atomic-size scanning probe has enabled imaging of nanoscale magnetic fields and single spins under ambient conditions. In this article we describe an experimental setup to operate this sensor in a cryogenic UHV environment. This will extend the applicability to a variety of molecular systems due to the enhanced target spin lifetimes at low temperature and the controlled sample preparation under UHV conditions. The instrument combines a tuning-fork based atomic force microscope (AFM) with a high numeric aperture confocal microscope and the facilities for application of radio-frequency (RF) fields for spin manipulation. We verify a sample temperature of <50 K even for strong laser and RF excitation and demonstrate magnetic resonance imaging with a magnetic AFM tip

  20. 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

    2016-01-01

    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. PMID:27023546

  1. 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.

  2. Interwell coupling effect in Si/SiGe quantum wells grown by ultra high vacuum chemical vapor deposition

    Directory of Open Access Journals (Sweden)

    Loh Ter-Hoe

    2007-01-01

    Full Text Available AbstractSi/Si0.66Ge0.34coupled quantum well (CQW structures with different barrier thickness of 40, 4 and 2 nm were grown on Si substrates using an ultra high vacuum chemical vapor deposition (UHV-CVD system. The samples were characterized using high resolution x-ray diffraction (HRXRD, cross-sectional transmission electron microscopy (XTEM and photoluminescence (PL spectroscopy. Blue shift in PL peak energy due to interwell coupling was observed in the CQWs following increase in the Si barrier thickness. The Si/SiGe heterostructure growth process and theoretical band structure model was validated by comparing the energy of the no-phonon peak calculated by the 6 + 2-bandk·pmethod with experimental PL data. Close agreement between theoretical calculations and experimental data was obtained.

  3. 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.

  4. Vacuum filtration based formation of liquid crystal films of semiconducting carbon nanotubes and high performance transistor devices

    International Nuclear Information System (INIS)

    In this paper, we report ultra-thin liquid crystal films of semiconducting carbon nanotubes using a simple vacuum filtration process. Vacuum filtration of nanotubes in aqueous surfactant solution formed nematic domains on the filter membrane surface and exhibited local ordering. A 2D fast Fourier transform was used to calculate the order parameters from scanning electron microscopy images. The order parameter was observed to be sensitive to the filtration time demonstrating different regions of transformation namely nucleation of nematic domains, nanotube accumulation and large domain growth.Transmittance versus sheet resistance measurements of such films resulted in optical to dc conductivity of σ opt/σ dc = 9.01 indicative of purely semiconducting nanotube liquid crystal network.Thin films of nanotube liquid crystals with order parameters ranging from S = 0.1–0.5 were patterned into conducting channels of transistor devices which showed high I on/I off ratios from 10–19 800 and electron mobility values μ e = 0.3–78.8 cm2 (V-s)−1, hole mobility values μ h = 0.4–287 cm2 (V-s)−1. High I on/I off ratios were observed at low order parameters and film mass. A Schottky barrier transistor model is consistent with the observed transistor characteristics. Electron and hole mobilities were seen to increase with order parameters and carbon nanotube mass fractions. A fundamental tradeoff between decreasing on/off ratio and increasing mobility with increasing nanotube film mass and order parameter is therefore concluded. Increase in order parameters of nanotubes liquid crystals improved the electronic transport properties as witnessed by the increase in σ dc/σ opt values on macroscopic films and high mobilities in microscopic transistors. Liquid crystal networks of semiconducting nanotubes as demonstrated here are simple to fabricate, transparent, scalable and could find wide ranging device applications. (papers)

  5. Artful creation

    DEFF Research Database (Denmark)

    Darsø, Lotte

    2013-01-01

    An introduction to the field of Arts-in-Business outlining 4 different approaches: 1) Art as decoration, 2) Art as intertainment, 3) Arts as instrumental, 4) Art as strategic......An introduction to the field of Arts-in-Business outlining 4 different approaches: 1) Art as decoration, 2) Art as intertainment, 3) Arts as instrumental, 4) Art as strategic...

  6. Vacuum extraction

    DEFF Research Database (Denmark)

    Maagaard, Mathilde; Oestergaard, Jeanett; Johansen, Marianne;

    2012-01-01

    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 of the scale. Main outcome measures. Consensus for the content of the scale. To test the scale of Cronbach's alpha, interclass correlation and differential item function was calculated in the prospective study. Results. 89% completed the first and 61% completed the second Delphi round. Hereafter...

  7. A unique dosing system for the production of OH under high vacuum for the study of environmental heterogeneous reactions

    International Nuclear Information System (INIS)

    A unique dosing system for the production of hydroxyl radicals under high vacuum for the study of environmental heterogeneous reactions is described. Hydroxyl radicals are produced by the photodissociation of a hydrogen peroxide aqueous gas mixture with 254 nm radiation according to the reaction H2O2+hν (254 nm)→OH+OH. Under the conditions of the current design, 0.6% conversion of hydrogen peroxide is expected yielding a hydroxyl number density on the order of 1010 molecules/cm3. The flux distribution of the dosing system is calculated using a Monte Carlo simulation method and compared with the experimentally determined results. The performance of this unique hydroxyl dosing system is demonstrated for the heterogeneous reaction with a solid surface of potassium iodide. Coupling of the hydroxyl radical dosing system to a quantitative surface analysis system should help provide molecular level insight into detailed reaction mechanisms

  8. Cu-TBPP and PTCDA molecules on insulating surfaces studied by ultra-high-vacuum non-contact AFM

    CERN Document Server

    Nony, L; Pfeiffer, O D; Gnecco, E D; Baratoff, A P; Meyer, E P; Eguchi, T; Gourdon, A; Joachim, C; Nony, Laurent; Bennewitz, Roland Prof.; Pfeiffer, Oliver Dr.; Gnecco, Enrico Dr.; Baratoff, Alexis Prof.; Meyer, Ernst Prof.; Eguchi, Toyoaki; Gourdon, Andr\\'{e}; Joachim, Chrisitan

    2004-01-01

    The adsorption of two kinds of porphyrin (Cu-TBPP) and perylene (PTCDA) derived organic molecules deposited on KBr and Al2O3 surfaces has been studied by non-contact force microscopy in ultra-high vacuum, our goal being the assembly of ordered molecular arrangements on insulating surfaces at room temperature. On a Cu(100) surface, well ordered islands of Cu-TBPP molecules were successfully imaged. On KBr and Al2O3 surfaces, it was found that the same molecules aggregate in small clusters at step edges, rather than forming ordered monolayers. First measurements with PTCDA on KBr show that nanometre-scale rectangular pits in the surface can act as traps to confine small molecular assemblies.

  9. A compact Ultra High Vacuum (UHV) compatible instrument for time of flight energy measurements of slow heavy reaction products

    International Nuclear Information System (INIS)

    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 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 ∼ 35 keV/nucleon from the interactions of 400 MeV/nucleon 16O with nat Xe gas targets

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

    International Nuclear Information System (INIS)

    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.

  11. 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.

  12. 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

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

    International Nuclear Information System (INIS)

    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. (paper)

  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. Searching for minicharged particles via birefringence, dichroism and Raman spectroscopy of the vacuum polarized by a high-intensity laser wave

    International Nuclear Information System (INIS)

    Absorption and dispersion of probe photons in the field of a high-intensity circularly polarized laser wave are investigated. The optical theorem is applied for determining the absorption coefficients in terms of the imaginary part of the vacuum polarization tensor. Compact expressions for the vacuum refraction indices and the photon absorption coefficients are obtained in various asymptotic regimes of interest. The outcomes of this analysis reveal that, far from the region relatively close to the threshold of the two-photon reaction, the birefringence and dichroism of the vacuum are small and, in some cases, strongly suppressed. On the contrary, in a vicinity of the region in which the photo-production of a pair occurs, these optical properties are manifest with lasers of moderate intensities. We take advantage of such a property in the search of minicharged particles by considering high-precision polarimetric experiments. In addition, Raman-like electromagnetic waves resulting from the inelastic part of the vacuum polarization tensor are suggested as an alternative form for finding exclusion limits on these hypothetical charge carriers. The envisaged parameters of upcoming high-intensity laser facilities are used for establishing upper bounds on the minicharged particles. -- Highlights: •Via dichroism and birefringence of the vacuum by a strong laser wave, minicharged particles can be probed. •The discovery potential is the highest in a vicinity of the first pair production threshold. •As alternative observable, Raman scattered waves are put forward

  16. 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

    ... FR 48180 at 48233), FDA included the Compliance Policy Guides Manual, which includes CPG Sec. 390.500... HUMAN SERVICES Food and Drug Administration Compliance Policy Guide Sec. 390.500 Definition of ``High... the withdrawal of Compliance Policy Guide Sec. 390.500 Definition of ``High-Voltage Vacuum...

  17. High-risk lesions diagnosed at MRI-guided vacuum-assisted breast biopsy: can underestimation be predicted?

    Energy Technology Data Exchange (ETDEWEB)

    Crystal, Pavel [Mount Sinai Hospital, University Health Network, Division of Breast Imaging, Toronto, ON (Canada); Mount Sinai Hospital, Toronto, ON (Canada); Sadaf, Arifa; Bukhanov, Karina; Helbich, Thomas H. [Mount Sinai Hospital, University Health Network, Division of Breast Imaging, Toronto, ON (Canada); McCready, David [Princess Margaret Hospital, Department of Surgical Oncology, Toronto, ON (Canada); O' Malley, Frances [Mount Sinai Hospital, Department of Pathology, Laboratory Medicine, Toronto, ON (Canada)

    2011-03-15

    To evaluate the frequency of diagnosis of high-risk lesions at MRI-guided vacuum-assisted breast biopsy (MRgVABB) and to determine whether underestimation may be predicted. Retrospective review of the medical records of 161 patients who underwent MRgVABB was performed. The underestimation rate was defined as an upgrade of a high-risk lesion at MRgVABB to malignancy at surgery. Clinical data, MRI features of the biopsied lesions, and histological diagnosis of cases with and those without underestimation were compared. Of 161 MRgVABB, histology revealed 31 (19%) high-risk lesions. Of 26 excised high-risk lesions, 13 (50%) were upgraded to malignancy. The underestimation rates of lobular neoplasia, atypical apocrine metaplasia, atypical ductal hyperplasia, and flat epithelial atypia were 50% (4/8), 100% (5/5), 50% (3/6) and 50% (1/2) respectively. There was no underestimation in the cases of benign papilloma without atypia (0/3), and radial scar (0/2). No statistically significant differences (p > 0.1) between the cases with and those without underestimation were seen in patient age, indications for breast MRI, size of lesion on MRI, morphological and kinetic features of biopsied lesions. Imaging and clinical features cannot be used reliably to predict underestimation at MRgVABB. All high-risk lesions diagnosed at MRgVABB require surgical excision. (orig.)

  18. 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

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

    International Nuclear Information System (INIS)

    Highlights: → The level of cross-links was improved to a certain extent. → The thermal stability was firstly improved and then decreased. → The transverse and longitudinal CTE were both determined by the degree of interfacial debonding. → The mass loss ratio increases firstly and then reaches a plateau value. → The surface morphology was altered and the surface roughness increased firstly and then decreased. → The transverse tensile strength was reduced. → The flexural strength increased firstly and then decreased to a plateau value. → 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 effect between the crosslinking degree

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

    OpenAIRE

    von Allwörden, Henning; Ruschmeier, Kai; 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 ...

  1. Vacuum welding of metals

    International Nuclear Information System (INIS)

    This new welding process has been developed by the Commissariat a l'Energie Atomique (CEA) in France. The edges of the work-pieces are melted by the impact of an electron beam produced by an electron gun. Welding is carried out in a vacuum of 10-4 to 10-8 mm of mercury. The welding machine consists, diagrammatically, of: a) a metal enclosure in which a vacuum is produced; b) a cathode for electron emission, a high-voltage generator for accelerating these electrons, a focusing device; c) a mechanical device for moving (rotating) the work-piece. Advantages of the process: 1) possible welding of highly oxidizable metals (e.g. zirconium); 2) fabrication of high-vacuum-sealed metal containers; 3) production of very deeply penetrated welds. Therefore, this new process is particularly advantageous for atomic power applications, the fabrication of electron tubes and, more generally, for all industries in which very special metals are used. (author)

  2. Student and teacher perspectives on art-infused science education in an urban high school in south Texas

    Science.gov (United States)

    de Leon, Debbie Lee Murray

    Over the past three decades there has been curricular and methodological integration of arts into core subjects. Existing literature illustrates a variety of factors inherent in art-integrated education which encourages a positive, effective, and successful learning experience. This process oriented study was initiated to gain the perspectives of students and teachers involved in traditional and art integrated biology classes teaching the concept of cells. The learning environments are contingent upon three different science instruction methods taught simultaneously (traditional, manual visualization and digital visualization). The study was done in an urban Charter High School in south Texas. Participants involved 58 high school biology students and two state certified science and art teachers. Three student focus groups, six student interviews, two teacher interviews as well as teacher journals was used to collect data. The framework utilized for this study was Hume's (2006) student engagement distinctions, school process and learning task. The resulting local conceptual model describes and compares the nature of each of the instruction-specific learning environments. Results indicated that students in art integrated biology classes benefited more than those involved in traditional class. Students are more engaged in art integrated instruction because they enjoyed a student-centered teacher-student interaction. Student outcomes with art infused methods show more active learning and had a higher chance of acquiring additional skills.

  3. Analysis of x-ray spectra emitted from highly ionized atoms in the vacuum spark and laser-produced high power plasma sources

    International Nuclear Information System (INIS)

    The interest in atomic spectroscopy has greatly been reinforced in the last ten years. This gain of interest is directly related to the developments in different fields of research where hot plasmas are created. These fields include in particular controlled thermonuclear fusion research by means of inertial or magnetic confinement approaches and also the most recent efforts to achieve lasers in the XUV region. The present work is based on the specific contribution of the atomic spectroscopy group at the Hebrew University. The recent development of both theoretical and experimental tools allowed us to progress in the understanding of the highly ionized states of heavy elements. In this work the low-inductance vacuum-spark developed at the Hebrew University was used as the hot plasma source. The spectra were recorded in the 7-300 A range by means of a high-resolution extreme-grazing-incidence spectrometer developed at the Racah Institute by Profs. J.L. Schwob and B.S. Fraenkel. To the extend the spectroscopic studies to higher-Z atoms, the laser-produced plasma facility at Soreq Nuclear Center was used. In this work the spectra of the sixth row elements were recorded in the x-rays by means of a crystal spectrometer. All these experimental systems are briefly described in chapter one. Chapter two deals with the theoretical methods used in the present work for the atomic calculations. Chapter three deals with the spectra of elements of the fifth row emitted from the vacuum-spark in the 30-150 A range. These spectra as experimental data were used in order to test ab-initio computations along the NiI sequence 3d-nl transitions. The results of this work are presented in chapter four. Chapter five is devoted to the measurement and analysis of spectra emitted from the vacuum-spark by rare-earth elements. (author)

  4. 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

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

    International Nuclear Information System (INIS)

    We conducted a series of laser induced breakdown spectroscopy (LIBS) experiments for K measurements under high vacuum conditions (10-6 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.% K2O and 40% for 3000 ppm K2O. If the amount of Ar is measured with 15% error for the 3.5 billion years rocks containing 1 and 0.3 wt.% K2O, 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 situ isochron K

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

    Science.gov (United States)

    Cho, Yuichiro; Sugita, Seiji; Kameda, Shingo; Miura, Yayoi N.; Ishibashi, Ko; Ohno, Sohsuke; Kamata, Shunichi; Arai, Tomoko; Morota, Tomokatsu; Namiki, Noriyuki; Matsui, Takafumi

    2015-04-01

    We conducted a series of laser induced breakdown spectroscopy (LIBS) experiments for K measurements under high vacuum conditions (10- 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.% K2O and 40% for 3000 ppm K2O. If the amount of Ar is measured with 15% error for the 3.5 billion years rocks containing 1 and 0.3 wt.% K2O, 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 situ isochron K-Ar dating

  7. Vacuum ultraviolet Ar excimer emission initiated by high intensity laser produced electrons

    International Nuclear Information System (INIS)

    We have observed Ar2* emission using a tabletop femtosecond high intensity laser as an excitation source. High intensity laser produced electrons via an optical field induced ionization (OFI) process initiated the Ar2* production kinetics, which made themselves analogous to those produced in an electron beam produced plasma. A fast conductive cooling of the OFI plasma was found to be appropriate to initiate the excimer formation kinetics more efficiently. (author)

  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. Calculation of the vacuum Green’s function valid even for high toroidal mode numbers in tokamaks

    Science.gov (United States)

    Chance, M. S.; Turnbull, A. D.; Snyder, P. B.

    2007-01-01

    The present evaluation of the Green's function used for the magnetic scalar potential in vacuum calculations for axisymmetric geometry has been found to be deficient even for moderately high, n, the toroidal mode number. This is relevant to the edge localized peeling-ballooning modes calculated by GATO, PEST and other MHD stability codes. The deficiency was due to the loss of numerical precision arising from the upward recursion relation used for generating the functions from the values at n = 0 from the complete elliptic integrals of the first and second kinds. To ameliorate this, a direct integration of the integral representation of the function is crafted to achieve the necessary high accuracy for moderately high mode numbers, with due consideration to the singular behavior of the integrand involved. At higher mode numbers the loss of numerical precision due to cancellations from the oscillatory behavior of the integrand is further avoided by judiciously deforming the integration contour into the complex plane to obtain a new integral representation for the Green's function. Near machine precision, roughly 12-16 digits, can be achieved by using a combination of these techniques. The relation to the associated Legendre functions, as well as a novel integral representation of these are also described.

  10. High-resolution three-dimensional spin- and angle-resolved photoelectron spectrometer using vacuum ultraviolet laser light

    Science.gov (United States)

    Yaji, Koichiro; Harasawa, Ayumi; Kuroda, Kenta; Toyohisa, Sogen; Nakayama, Mitsuhiro; Ishida, Yukiaki; Fukushima, Akiko; Watanabe, Shuntaro; Chen, Chuangtian; Komori, Fumio; Shin, Shik

    2016-05-01

    We describe a spin- and angle-resolved photoelectron spectroscopy (SARPES) apparatus with a vacuum-ultraviolet (VUV) laser (hν = 6.994 eV) developed at the Laser and Synchrotron Research Center at the Institute for Solid State Physics, The University of Tokyo. The spectrometer consists of a hemispherical photoelectron analyzer equipped with an electron deflector function and twin very-low-energy-electron-diffraction-type spin detectors, which allows us to analyze the spin vector of a photoelectron three-dimensionally with both high energy and angular resolutions. The combination of the high-performance spectrometer and the high-photon-flux VUV laser can achieve an energy resolution of 1.7 meV for SARPES. We demonstrate that the present laser-SARPES machine realizes a quick SARPES on the spin-split band structure of a Bi(111) film even with 7 meV energy and 0.7∘ angular resolutions along the entrance-slit direction. This laser-SARPES machine is applicable to the investigation of spin-dependent electronic states on an energy scale of a few meV.

  11. Development of High Power Vacuum Tubes for Accelerators and Plasma Heating

    International Nuclear Information System (INIS)

    High pulsed power magnetrons and klystrons for medical and industrial accelerators, and high CW power klystrons and gyrotrons for plasma heating in tokamak, are being developed at CEERI. S-band 2.0MW pulsed tunable magnetrons of centre frequency 2856MHz and 2998 MHz were developed, and S-band 2.6MW pulsed tunable magnetron is being developed for medical LINAC, and 3MW pulsed tunable magnetron is being developed for industrial accelerator. S-band (2856MHz), 5MW pulsed klystron was developed for particle accelerator, and S-band 6MW pulsed klystron is under development for 10MeV industrial accelerator. 350MHz, 100kW (CW) klystron is being developed for proton accelerator, and C-band 250kW (CW) klystron is being developed for plasma heating. 42GHz, 200kW (CW/Long pulse) gyrotron is under development for plasma heating. Plasma filled tubes are also being developed for switching. 25kV/1kA and 40kV/3kA thyratrons were developed for high voltage high current switching in pulse modulators for magnetrons and klystrons. 25kV/3kA Pseudospark switch of current rise time of 1kA/|a-sec and pulse repetition rate of 500Hz is being developed. Plasma assisted high power microwave device is also being investigated.

  12. Development of High Power Vacuum Tubes for Accelerators and Plasma Heating

    Science.gov (United States)

    Srivastava, Vishnu

    2012-11-01

    High pulsed power magnetrons and klystrons for medical and industrial accelerators, and high CW power klystrons and gyrotrons for plasma heating in tokamak, are being developed at CEERI. S-band 2.0MW pulsed tunable magnetrons of centre frequency 2856MHz and 2998 MHz were developed, and S-band 2.6MW pulsed tunable magnetron is being developed for medical LINAC, and 3MW pulsed tunable magnetron is being developed for industrial accelerator. S-band (2856MHz), 5MW pulsed klystron was developed for particle accelerator, and S-band 6MW pulsed klystron is under development for 10MeV industrial accelerator. 350MHz, 100kW (CW) klystron is being developed for proton accelerator, and C-band 250kW (CW) klystron is being developed for plasma heating. 42GHz, 200kW (CW/Long pulse) gyrotron is under development for plasma heating. Plasma filled tubes are also being developed for switching. 25kV/1kA and 40kV/3kA thyratrons were developed for high voltage high current switching in pulse modulators for magnetrons and klystrons. 25kV/3kA Pseudospark switch of current rise time of 1kA/|a-sec and pulse repetition rate of 500Hz is being developed. Plasma assisted high power microwave device is also being investigated.

  13. For What Purpose the Arts? An Analysis of the Mission Statements of Urban Arts High Schools in Canada and the United States

    Science.gov (United States)

    Gaztambide-Fernández, Rubén; Nicholls, Rachael; Arráiz-Matute, Alexandra

    2016-01-01

    While general arts programs have declined in many schools across the United States and Canada, the number of specialized art programs in public secondary schools has swelled since the 1980s. While this increase is often celebrated by arts educators, questions about the justification of specialized arts programs are rarely raised, and their value…

  14. 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.

  15. 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

    We report on a directional atomic beam created using an alkali metal dispenser and a nozzle. By applying a high current (15 A) pulse to the dispenser at room temperature we can rapidly heat it to a temperature at which it starts dispensing, avoiding the need for preheating. The atomic beam produced...

  16. High-vacuum synthesis of SiC from rice husk: a novel method

    Science.gov (United States)

    Sarangi, M.; Mallick, B.; Mishra, S. C.; Tiwari, T. N.; Nayak, P.

    2013-08-01

    A new technique for the production of SiC from rice husk is reported in this paper. The high-purity β-SiC is synthesized in a short time of 5 min. The samples are characterized by x-ray diffraction and scanning electron microscopy analysis. The results are compared with the previously reported result that was obtained by conventional process.

  17. High-vacuum synthesis of SiC from rice husk: a novel method

    International Nuclear Information System (INIS)

    A new technique for the production of SiC from rice husk is reported in this paper. The high-purity β-SiC is synthesized in a short time of 5 min. The samples are characterized by x-ray diffraction and scanning electron microscopy analysis. The results are compared with the previously reported result that was obtained by conventional process. (paper)

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

    International Nuclear Information System (INIS)

    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

  19. 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.

  20. High-RRR thin-films of NB produced using energetic condensation from a coaxial, rotating vacuum ARC plasma (CEDTM)

    International Nuclear Information System (INIS)

    We have recently demonstrated unprecedentedly high values of RRR (up to 542) in thin-films of pure Nb deposited on a-plane sapphire and MgO crystal substrates. The Nb films were grown using a vacuum arc discharge struck between a reactor grade Nb cathode rod (RRR ∼ 30) and a coaxial, semi-transparent Mo mesh anode, with a heated substrate placed just outside it. The substrates were pre-heated for several hours prior to deposition at different temperatures. Low pre-heat temperatures (600 C) is correlated with better epitaxial crystal structure in both a-sapphire and MgO substrate grown films. However, the SIMS data reveal that the most important requirement for high-RRR Nb films on either substrate is the reduction of impurities in the film, especially hydrogen. The hydrogen content in the MgO grown films is 1000 times lower than in bulk Nb tested as a reference from SRF cavity grade Nb. This result has potential implications for SRF accelerators. Coating bulk Nb cavities with an MgO layer followed by our CEDTM deposited Nb films, might create superior SRF cavities that would avoid Q-slope and operate at higher peak fields.

  1. Ultrahigh vacuum sample mount for x-ray photoelectron spectroscopy up to very high temperature (150-1400 K)

    International Nuclear Information System (INIS)

    Spectroscopic studies are rarely performed at very high temperature, especially when combined with light from a synchrotron source. Demanding conditions of maintaining ultrahigh vacuum (UHV) during heating, together with the typically brief access to beam time at multiuser synchrotron end stations, may contribute to some of the reasons for the difficulty of such experiments. Consequently, a large number of materials with interesting properties and industrial applications at high temperature remain unexplored. The authors describe here a simple portable sample mount assembly that can be easily utilized at a beamline, with potential utility for a variety of spectroscopic measurements requiring elevated temperatures and an UHV environment. In the specific application described here, the authors use a resistive cartridge heater interfaced with a standard manipulator previously designed for cooling by liquid nitrogen with an UHV chamber and a cylindrical mirror analyzer for x-ray photoemission spectroscopy (XPS) [also known as electron spectroscopy for chemical analysis (ESCA)] at the Synchrotron Radiation Center in Stoughton, WI. The heater cartridge required only modest power to reach target temperatures using an open-loop temperature control. Finally, the authors describe the measurements of XPS (ESCA) and total-electron yield x-ray absorption spectroscopy on nanopowders and on single crystals grown by them. They emphasize the simplicity of the setup, which they believe would be of interest to groups performing measurements at large facilities, where access and time are both limited.

  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. 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

    The complete description of a high power spectrometer, allowing for large area illumination of up to 10 cm(2) in the wavelength range 200-800 nm with average power densities of 2 mW cm(2), is provided. The setup employs a stationary 150 W xenon lamp used in conjunction with a simple stationary...... selected part of the diffracted beam of the monochromator. The typical spectral resolution was 12 nm cm(-1) which gave bandwidths of 25 nm with a 2 cm sample width. The electrical characteristics of the photovoltaic device under test was measured using a source meter giving an experimental current...

  4. Field-proven high-power vacuum tubes for plasma fusion applications

    International Nuclear Information System (INIS)

    For applications in plasma heating for fusion experiments, especially for HV power supplies for neutral beam injectors and gyrotrons as well as ion cyclotron frequency generation, fieldproven high power tetrodes are available from Brown Boveri. Two types of tetrodes from Brown Boveri are discussed, the CQK 200-4 and CQK 650-2. Since their introduction, these tubes and their accessories have been further developed according to user requirements, and considerable production, testing and field experience has been accumulated. This paper summarizes the present technical status and the performance data achieved to date

  5. Study of high coercive force films made by vacuum deposition of cobalt onto chromium

    International Nuclear Information System (INIS)

    A new method to make high coercive force films, by successive evaporations of chromium and cobalt, was demonstrated in 1966 at the 'Laboratoire d'Electronique et de Technologie de l'Informatique'. This work first contains a description of the magnetic properties of these films according to the conditions of preparation. These properties, which are isotropic in the plane of the film, are then related to the crystallographic structure of chromium and cobalt, in particular through electron microscopy. It is concluded that the coercive force is essentially due to the high magneto-crystalline anisotropy of cobalt in its hexagonal phase and depends, altogether with the shape of the hysteresis loop, on the magnetostatic coupling between the grains, which varies according to their dimensions. The chromium underlayer, if its surface is free enough of oxygen contamination, induces the growth of the hexagonal phase and influences the grain size of cobalt by a sort of epitaxy. At last, the behaviour of the Co/Cr films as a magnetic recording material is briefly examined and discussed. (author)

  6. 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

  7. 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...

  8. 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.

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

    International Nuclear Information System (INIS)

    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

  10. The State of the Art of the Borehole Disposal Concept for High Level Radioactive Waste

    International Nuclear Information System (INIS)

    As an alternative of the high-level radioactive waste disposal in the subsurface repository, a deep borehole disposal is reviewed by several nuclear advanced countries. In this study, the state of the art on the borehole disposal researches was reviewed, and the possibility of borehole disposal in Korean peninsula was discussed. In the deep borehole disposal concept radioactive waste is disposed at the section of 3 - 5 km depth in a deep borehole, and it has known that it has advantages in performance and cost due to the layered structure of deep groundwater and small surface disposal facility. The results show that it is necessary to acquisite data on deep geologic conditions of Korean peninsula, and to research the engineering barrier system, numerical modeling tools and disposal techniques for deep borehole disposal.

  11. 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.

  12. FMIT accelerator vacuum system

    International Nuclear Information System (INIS)

    The Fusion Materials Irradiation Test (FMIT) Facility accelerator is being designed to continuously accelerate 100-mA deuterons to 25 MeV. High vacuum pumping of the accelerator structure and beam lines will be done by ion pumps and titanium sublimation pumps. The design of the roughing system includes a Roots blower/mechanical pump package. For economy the size of the system has been designed to operate at 10-6 torr, where beam particle scattering on residual gases is negligible. For minimum maintenance in this neutron factory, the FMIT vacuum system is designed from the point of view of simplicity and reliability

  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. About an expansion of a high-power-laser produced plasma in vacuum

    International Nuclear Information System (INIS)

    Complete test of publication follows. We consider the results of an experimental investigation of the temporal evolution of plasmas produced by high power laser irradiation of various materials. The experiment was done at the LULI Laboratory (Ecole Polytechnique, Paris). The investigation of hydrodynamics expansion of laser-produced plasmas (in the intensity range I ∼ 1014 W/cm3) is fundamental for several physics areas, first of all inertial confinement fusion. Although several theoretical models of plasma expansion were developed already in the 70's and in the 80's and many experiments have studied this aspect, still there are not many clean experimental results. In recent years, several techniques have been introduced which allow the production of flat-top intensity profiles. Hence one fundamental experimental parameter, the laser intensity on target, is clearly defined, which is not the usual Gaussian-like intensity distribution or, even worse, with typical focal spots affected by hot spots. This allows a well-characterized study of plasma expansion. Also, 2D effects in plasma expansion are strongly reduced, getting much closer to that described by 1D theoretical models. One of such technique is that of Phase Zone Plates which appeared in recent years, and which was also used in our experiment. The experimental set up includes a Nd:glass high power laser system with typical intensity of 1014 W/cm3 (the temporal profile is approximately trapezoidal with rise and fall time of 150 ps and a flat top duration of 600 ps), a probe beam (Nd laser converted to 2ω) coupled to an interferometer and to a streak-camera with ps resolution. The diagnostic system allows the evolution of the plasma density profile to be measured as a function of time. We report the result of 5 shots performed with 3 kinds of target material (Au, Al, and CH2). The comparison between theoretical predictions, computer simulations and experimental data are provided. The authors warmly

  15. Direct current breakdown in gases for complex geometries from high vacuum to atmospheric pressure

    International Nuclear Information System (INIS)

    The demand for improved performances of power transmission devices requires ever smaller dimensions and higher working voltages which lead to increased risk of breakdown, for example, in satellite slip rings. Previous works are mostly limited to breakdown in simple geometries such as parallel plates or pin to plate. Here we discuss the effect of more complex geometries for dc breakdown in gases over a large pressure range (2 × 10−5 to 103 mbar). Experimental measurements of dc gas discharge breakdown in a ring assembly geometry are compared with a numerical simulation model for gas breakdown using a fluid model. Starting with parallel plates (1 and 100 mm gap width representing approximately the shortest and longest electric field path lengths in the ring assembly geometry) and extending to double gap and multi-gap geometries, an understanding of the overall shape of the breakdown voltage versus pressure curve is established. The high (low) pressure thresholds of gas discharge are determined by the shortest (longest) electric field path length in a complex geometry. Moreover, the availability of multiple path lengths leads to a breakdown voltage minimum over a wide range of intermediate pressure because breakdown can occur in the most favourable gap. Finally, the numerical simulation in the ring assembly shows the importance of parameters such as the secondary electron emission coefficient which play a major role in determining the breakdown voltage value. (paper)

  16. Beam tube vacuum in low field and high field very large hadron colliders

    International Nuclear Information System (INIS)

    Bounds on the beam tube gas pressure and the required pumping speed are estimated for ∼ 2 T low field (LF) and - 12 T high field (HF) 100 TeV center-of-mass hadron colliders. In both cases photodesorption by synchrotron radiation is the dominant source of gas. Assuming beam-gas scattering limited luminosity lifetime five times the IP scattering lifetime, the required CO equivalent beam tube pressure is 0.25 ntorr for LF and 1.8 ntorr for HF, ambient room temperature equivalent. The CO equivalent pumping speeds required to achieve this pressure within a reasonable beam conditioning time (a few tenths of an operational year at design intensity) are estimated to be ∼ 300 I/s-m for LF and - 40 I/s-m for HF. For the LF case with a superferric warm and a distributed NEG plus lumped ion or cryo pump system is considered. The size of antechamber needed, ID- 6 cm, requires that it be located outside the - 2 cm C-coil magnet gap. Lumped pumps for pumping CH4 need to be spaced at - 20 in intervals on the antechamber. For the HF case the likely beam tube temperature .is 15-20 K and cryopumping with a beam screen system is considered. The necessary pumping speed can be achieved with slots covering ∼ 2 per cent of the beam screen surface

  17. 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

  18. Frozen Vacuum

    CERN Document Server

    Bousso, Raphael

    2014-01-01

    Modes just outside the horizon of a typical old black hole are thermally entangled with distant Hawking radiation. This precludes their entangled purity with interior modes, leading to a firewall. Identifying the interior with the distant radiation ("A=R_B", "ER=EPR") can resolve the entanglement conflict. But the map must adjust for any interactions, or else the firewall will reappear if the Hawking radiation scatters off the CMB. With a self-correcting map, an infalling observer is unable to excite the vacuum near the horizon. This allows the horizon to be locally detected and so violates the equivalence principle.

  19. Generation of vacuum ultraviolet radiation by intracavity high-harmonic generation toward state detection of single trapped ions

    CERN Document Server

    Wakui, Kentaro; Ido, Tetsuya

    2014-01-01

    Optical clocks based on trapped ions with two outer electrons supply frequency accuracy in the order of $10^{-18}$ level. The difficulties of the present implementation with quantum logic spectroscopy might be overcome if vacuum ultraviolet (VUV) radiation is available for detecting the ions by direct excitation of their electronic transitions in the VUV region. We report generation of VUV radiation at around 159 nm toward this goal by intracavity high-harmonic generation. The radiation is generated as the fifth harmonic of a femtosecond Ti:S oscillator in a xenon gas jet placed at the beam waist of a passive femtosecond enhancement cavity. A fluoride-multilayer-coated output-coupler was designed for this wavelength, and we experimentally confirmed its reflectance in the VUV region. Using this coupler, an average power reaching 6.4 $\\mu$W at around 159 nm is coupled out from a modest fundamental power of 650 mW. When a single comb component out of $1.9\\times10^5$ teeth is resonant to the atomic transition, hu...

  20. Measurement of phenol and p-cresol in urine and feces using vacuum microdistillation and high-performance liquid chromatography.

    Science.gov (United States)

    King, Roger A; May, Bruce L; Davies, Debbie A; Bird, Anthony R

    2009-01-01

    In this article, we describe a simple, sensitive, accurate, and repeatable method for the measurement of phenol and p-cresol (4-methylphenol) in human urine and feces. We examined a number of parameters to identify an optimal extraction protocol. Purification of sample extracts was achieved by low-temperature vacuum microdistillation. Separation was achieved in approximately 15 min by high-performance liquid chromatography (HPLC) with quantification by fluorescence at 284/310 nm. Limits of detection for phenol were 2 ng/ml for urine and 20 ng/g for feces, and those for p-cresol were 10 ng/ml for urine and 100 ng/g for feces. For comparison, approximate mean values for urine are 3 microg/ml for phenol and 30 microg/ml for p-cresol, and those for feces are 1 microg/g for phenol and 50 microg/g for p-cresol. An experienced analyst can process 60 samples each day using this method. PMID:18848516

  1. Reduction of Vanadium Oxide (VOx) under High Vacuum Conditions as Investigated by X-Ray Photoelectron Spectroscopy

    Science.gov (United States)

    Chourasia, A.

    2015-03-01

    Vanadium oxide thin films were formed by depositing thin films of vanadium on quartz substrates and oxidizing them in an atmosphere of oxygen. The deposition was done by the e-beam technique. The oxide films were annealed at different temperatures for different times under high vacuum conditions. The technique of x-ray photoelectron spectroscopy has been employed to study the changes in the oxidation states of vanadium and oxygen in such films. The spectral features in the vanadium 2p, oxygen 1s, and the x-ray excited Auger regions were investigated. The Auger parameter has been utilized to study the changes. The complete oxidation of elemental vanadium to V2O5 was observed to occur at 700°C. At any other temperature, a mixture of oxides consisting of V2O5 and VO2 was observed in the films. Annealing of the films resulted in the gradual loss of oxygen followed by reduction in the oxidation state from +5 to 0. The reduction was observed to depend upon the annealing temperature and the annealing time. Organized Research, TAMU-Commerce.

  2. Vacuum-arc chromium coatings for Zr-1%Nb alloy protection against high-temperature oxidation in air

    International Nuclear Information System (INIS)

    The effect of vacuum-arc Cr coatings on the alloy E110 resistance to the oxidation in air at temperatures 1020 and 1100 deg C for 3600 s has been investigated. The methods of scanning electron microscope, X-ray analysis and nanoindentation were used to determine the thickness, phase, mechanical properties of coatings and oxide layers. The results show that the chromium coating can effectively protect fuel tubes against high-temperature oxidation in air for one hour. In the coating during oxidation at T = 1100 deg C a Cr2O3 oxide layer of 5 μm thickness is formed preventing further oxygen penetration into the coating, and thus the tube shape is conserved. Under similar test conditions the oxidation of uncoated tubes with formation of a porous monocline oxide of ZrO2 of a thickness more than ≥ 250 μm is observed, then the deformation and cracking of samples occur and the oxide layer breaks away

  3. Discontinuation of cART postpartum in a high prevalence district of South Africa in 2014

    OpenAIRE

    Claessens, Lore; Voce, Anna; Knight, Stephen; Sartorius, Benn; Coovadia, Ashraf

    2014-01-01

    Background Combination antiretroviral therapy (cART) is the current strategy to prevent mother-to-child transmission (PMTCT) of HIV. Women initiated on cART should continue taking treatment life-long or stop after cessation of breastfeeding depending on their CD4 cell count or on their World Health Organization (WHO) staging. Keeping people living with HIV on treatment is essential for the success of any antiretroviral therapy (ART) programme. There has been a rapid scale-up of cART in the PM...

  4. The FTU (Frascati Tokamak Upgrade) vacuum chamber

    International Nuclear Information System (INIS)

    The FTU vacuum vassel has been designed to withstand high electromagnetic and thermal loads and to reach high vacuum conditions which are essential to obtain clean, impurity free plasma. After a survey of the vacuum chamber requirements and of the design development, the paper reports the main manufactoring process such as welding, stress relieving, machining, nondestructive testing, outgassing and preassembly

  5. Vacuum ultra-violet emission of plasma discharges with high Xe partial pressure using a cathode protective layer with high secondary electron emission

    International Nuclear Information System (INIS)

    In this work, the mechanism of the vacuum ultra-violet (VUV) emission of plasma discharges, with high Xe partial pressure and high ion-induced secondary electrons emission protective layer, is studied by measuring the VUV light emission directly and comparing it with two-dimensional simulations. From the panel measurement, we find that the high intensity of excimer VUV mainly contributes to the high luminous efficacy of SrCaO-plasma display panels (PDP) at a low sustain voltage. The unchanged Xe excitation efficiency indicates that the electron temperature is not decreased by the high secondary electrons emission protective layer, even though the sustain voltage is much lower. From the two-dimensional simulations, we can find that the ratio of excimer VUV to resonant VUV, which is determined by the collision rate in the discharge, is only significantly affected by the Xe partial pressure, while it is independent of the sustain voltage and the secondary-electrons-emission capability of protective layer. The unchanged average electron energy at the moment when the electric field becomes maximum confirms that the improvement of the VUV production efficiency mainly is attributed to the increase in electron heating efficiency of a PDP with high ion-induced secondary electrons emission protective layer. Combining the experimental and the simulation results, we conclude about the mechanism by which the VUV production is improved for the plasma display panel with a high Xe partial pressure and a cold cathode with high ion-induced secondary electrons emission

  6. Identification of Mathematics Competencies Taught in Industrial Arts/Technology Education Programs in Louisiana High Schools. Vocational Education Research.

    Science.gov (United States)

    Northwestern State Univ., Natchitoches, LA.

    A study that identified mathematics processes and concepts taught in industrial arts-technology education courses in Louisiana high schools and the time spent teaching used the following methods: literature review; phone interviews with persons recognized nationally for their efforts at infusing math, science, and technology into the high school…

  7. A Different Perspective t o Fine Art High School Students i n Emotional Intelligence

    Directory of Open Access Journals (Sweden)

    Öznur TULUNAY ATEŞ

    2014-12-01

    Full Text Available The aim of this study is to examine the emot ional intelligence of different high school students . To this end; EQ - NED and personal information form developed by the researcher were used to collect information about the variable in order to determine the emotional intelligence of the participating st udents to the research. In this study data were collected from a total of 439, 246 female and 193 male students through these scales . T he data were analyzed by using SPSS Windows 17.0 program . To evaluate the data , descriptive statistical methods (frequenc y, percentage, mean, standard deviation were used. Kruskal - Wallis H - test and Mann - Whitney U analysis test were usedas non - parametric hypothesis testing procedures. According to the r esearch results, the mean of the total score of emotional intelligence sho wed a significant difference in terms of school variables where the students study . In the study, EQ T, EQ 1, EQ 2 and EQ 3 scores of the students studying Fine Arts and Sports High School are found higher than the students studying in other high schools.

  8. Excellent outcomes among HIV+ children on ART, but unacceptably high pre-ART mortality and losses to follow-up: a cohort study from Cambodia.

    OpenAIRE

    Soeung Seithabot; Te Vantha; Zachariah Rony; Isaakidis Petros; Raguenaud Marie-Eve; Akao Kazumi; Kumar Varun

    2009-01-01

    Abstract Background Although HIV program evaluations focusing on mortality on ART provide important evidence on treatment effectiveness, they do not asses overall HIV program performance because they exclude patients who are eligible but not started on ART for whatever reason. The objective of this study was to measure mortality that occurs both pre-ART and during ART among HIV-positive children enrolled in two HIV-programs in Cambodia. Methods Retrospective cohort study on 1168 HIV-positive ...

  9. Study of impurity distribution in mechanically polished, chemically treated and high vacuum degassed pure niobium samples using the TOFSIMS technique

    Science.gov (United States)

    Bose, A.; Joshi, S. C.

    2015-07-01

    The performance of superconducting radio frequency (SRF) cavities is strongly influenced by various impurities within the penetration depth (∼50 nm) of niobium (Nb), which in turn depends on the applied surface treatments. The effect of these surface treatments on the impurities of Nb has been explored using various surface analytical techniques. However, the results are still inadequate in many aspects and the effect of sequential SRF treatments on the impurity distribution has not been explored. The present study analyzes various impurities within the penetration depth of Nb samples, treated by SRF cavity processing techniques such as colloidal silica polishing (simulating centrifugal barrel polishing), buffer chemical polishing (BCP), high pressure rinsing (HPR) and degassing under a high vacuum (HV) condition at 600 °C for 10 h. Static, dynamic and slow sputtering modes of the time of flight secondary ion mass spectrometry (TOFSIMS) technique were employed to study the effect of the above treatments on interstitial impurities, hydrocarbons, oxides, acidic residues, reaction products and metallic contaminations. The study confirms that the impurity distribution in Nb is not only sensitive to the surface treatments, but also to their sequence. Varying the treatment sequence prior to HV degassing treatments affected the final impurity levels in HV degassed bulk Nb samples. The HV degassing treatment was capable of reducing hydrogen contamination, but oxygen, carbon and metallic impurities were introduced into bulk Nb due to poor isolation from furnace contamination. On the other hand, BCP treated samples exhibited minimum hydrocarbon and metallic contamination along with the thinnest oxide layer at ∼2.8 nm, but led to extensive contamination of the oxide layer with residuals and reaction products of acids used in the BCP solution. HPR treatment, on the other hand, was effective in reducing the acidic impurities on the top surface. Variability of the

  10. Integrating atomic layer deposition and ultra-high vacuum physical vapor deposition for in situ fabrication of tunnel junctions

    International Nuclear Information System (INIS)

    Atomic Layer Deposition (ALD) is a promising technique for growing ultrathin, pristine dielectrics on metal substrates, which is essential to many electronic devices. Tunnel junctions are an excellent example which require a leak-free, ultrathin dielectric tunnel barrier of typical thickness around 1 nm between two metal electrodes. A challenge in the development of ultrathin dielectric tunnel barriers using ALD is controlling the nucleation of dielectrics on metals with minimal formation of native oxides at the metal surface for high-quality interfaces between the tunnel barrier and metal electrodes. This poses a critical need for integrating ALD with ultra-high vacuum (UHV) physical vapor deposition. In order to address these challenges, a viscous-flow ALD chamber was designed and interfaced to an UHV magnetron sputtering chamber via a load lock. A sample transportation system was implemented for in situ sample transfer between the ALD, load lock, and sputtering chambers. Using this integrated ALD-UHV sputtering system, superconductor-insulator-superconductor (SIS) Nb-Al/Al2O2/Nb Josephson tunnel junctions were fabricated with tunnel barriers of thickness varied from sub-nm to ∼1 nm. The suitability of using an Al wetting layer for initiation of the ALD Al2O3 tunnel barrier was investigated with ellipsometry, atomic force microscopy, and electrical transport measurements. With optimized processing conditions, leak-free SIS tunnel junctions were obtained, demonstrating the viability of this integrated ALD-UHV sputtering system for the fabrication of tunnel junctions and devices comprised of metal-dielectric-metal multilayers

  11. High-RRR thin-films of NB produced using energetic condensation from a coaxial, rotating vacuum ARC plasma (CEDTM)

    Science.gov (United States)

    Valderrama, Enrique Francisco; James, Colt; Krishnan, Mahadevan; Zhao, Xin; Phillips, Larry; Reece, Charles; Seo, Kang

    2012-06-01

    We have recently demonstrated unprecedentedly high values of RRR (up to 542) in thin-films of pure Nb deposited on a-plane sapphire and MgO crystal substrates. The Nb films were grown using a vacuum arc discharge struck between a reactor grade Nb cathode rod (RRR 30) and a coaxial, semi-transparent Mo mesh anode, with a heated substrate placed just outside it. The substrates were pre-heated for several hours prior to deposition at different temperatures. Low pre-heat temperatures (RRR (RRR=214 on a-sapphire and RRR=542 on MgO. XRD (Bragg-Brentano scans and Pole Figures), EBSD and SIMS data reveal several features: (1) on asapphire, higher temperatures show better 3D registry for epitaxial growth of Nb; the crystal structure evolves from textured, polycrystalline (with twins) to single-crystal; (2) on MgO, there is a transition from {110} planes to {100} as the temperature is increased beyond 500°C. The dramatic increase in RRR (from 10 at 600°C) is correlated with better epitaxial crystal structure in both a-sapphire and MgO substrate grown films. However, the SIMS data reveal that the most important requirement for high-RRR Nb films on either substrate is the reduction of impurities in the film, especially hydrogen. The hydrogen content in the MgO grown films is 1000 times lower than in bulk Nb tested as a reference from SRF cavity grade Nb. This result has potential implications for SRF accelerators. Coating bulk Nb cavities with an MgO layer followed by our CEDTM deposited Nb films, might create superior SRF cavities that would avoid Q-slope and operate at higher peak fields. This research was supported by Department of Energy grants DE-SC0004994 and DE-FG02-08ER85162.

  12. 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).

  13. 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). PMID:27475560

  14. Vacuum properties of high quality value tuning fork in high magnetic field up to 8 Tesla and at mK temperatures

    International Nuclear Information System (INIS)

    Tuning forks are very popular experimental tools widely applied in low and ultra low temperature physics as mechanical resonators and cantilevers in the study of quantum liquids, STM and AFM techniques, etc. As an added benefit, these forks being cooled, have very high Q-value, typically 106 and their properties seems to be magnetic field independent. We present preliminary vacuum measurements of a commercial tuning fork oscillating at frequency 32 kHz conducted in magnetic fields up to 8 T and at temperature ∼ 10 mK. We found an additional weak damping of the tuning fork motion depending on magnetic field magnitude and we discuss physical nature of the observed phenomena

  15. 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).

  16. Experimental study on the effect of applying a crossed magnetic field on the insulator flashover behavior in high vacuum

    Science.gov (United States)

    Abu-Elabass, K.

    2015-09-01

    In this study, a possible method of reducing the flashover stress is achieved by the effect of an additional magnetic field in the transverse direction on the main applied electric field. The degree of vacuum used in this study was 5×10-5 Pa. The magnetic flux density B employed in this study extends from 4×10-3 to 24×10-3 T. From the results obtained throughout this work, the transverse magnetic field increases the flashover voltage and decreases the leakage current. The effect of the transverse magnetic field on the surface flashover of the dielectric solid in vacuum shows a marked dependence on the material and the thickness of the test specimen, the vacuum degree, the type of electric field (AC or DC) as well as the type of magnetic field (AC or DC).

  17. Arte precolombino, arte moderno y arte latinoamericano

    OpenAIRE

    Gamboa Hinestrosa, Pablo

    2014-01-01

    ¿Cuál es la vigencia del arte precolombino? ¿Qué ha aportado ala corriente del arte universal? ¿Qué se deben mutuamente arte modernoy arte precolombino? Estos planteamientos nos sirven para establecerla vigencia del arte precolombino en Latinoamérica, buscandoantecedentes desde los tiempos de la Conquista hasta nuestros días.

  18. 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

  19. State-of-the-art exposure chamber for highly controlled and reproducible THz biological effects studies

    Science.gov (United States)

    Cerna, Cesario Z.; Elam, David P.; Echchgadda, Ibtissam; Sloan, Mark A.; Wilmink, Gerald J.

    2014-03-01

    Terahertz (THz) imaging and sensing technologies are increasingly being used at international airports for security screening purposes and at major medical centers for cancer and burn diagnosis. The emergence of new THz applications has directly resulted in an increased interest regarding the biological effects associated with this frequency range. Knowledge of THz biological effects is also desired for the safe use of THz systems, identification of health hazards, and development of empirically-based safety standards. In this study, we developed a state-of-the-art exposure chamber that allowed for highly controlled and reproducible studies of THz biological effects. This innovative system incorporated an industry grade cell incubator system that permitted a highly controlled exposure environment, where temperatures could be maintained at 37 °C +/- 0.1 °C, carbon dioxide (CO2) levels at 5% +/- 0.1%, and relative humidity (RH) levels at 95% +/- 1%. To maximize the THz power transmitted to the cell culture region inside the humid incubator, a secondary custom micro-chamber was fabricated and incorporated into the system. This micro-chamber shields the THz beam from the incubator environment and could be nitrogen-purged to eliminate water absorption effects. Additionally, a microscope that allowed for real-time visualization of the live cells before, during, and after THz exposure was integrated into the exposure system.

  20. Characteristics of three-grid type modulated Bayard-Alpert ionization gauge in ultra high vacuum region

    International Nuclear Information System (INIS)

    In Bayard-Alpert (B-A) ionization gauges widely used as total pressure-measuring gauges, the collector current is expressed as the sum of ion current Ii and soft X-ray photoelectron current Ix, if noise current is composed of only Ix. Ii and Ix are proportional to emission current Ie, respectively, and the pressure Px = α/S at which Ie is equal to Ix is called X-ray limit pressure, where α is X-ray current generating rate, and S is sensitivity coefficient. Therefore, it is necessary to make α smaller, and at the same time, to make S larger in order to reduce Px. But actually, the noise current is not composed of Ix only. Thereupon, the collector current other than true ion current in the lump is expressed as In, then the measuring limit pressure can be improved by epsilon n/kappa fold, where epsilon n and kappa are modulation coefficients of In and Ii, respectively. The authors have studied the three concentric cylindrical grid type modulated B-A gauge, and presently are working to try to make epsilon n smaller, putting the emphasis on holding the electric field around the collector constant. By the detailed consideration on the noise current of this gauge, it can be expected that the gauge holds linearity down to considerably low pressure region, but there are many problems to verify it. Thus this gauge is expected to be developed further as the gauges for ultra-high vacuum application. (Wakatsuki, Y.)

  1. Vacuum Arc Ion Sources

    OpenAIRE

    Brown, I.

    2014-01-01

    The vacuum arc ion source has evolved into a more or less standard laboratory tool for the production of high-current beams of metal ions, and is now used in a number of different embodiments at many laboratories around the world. Applications include primarily ion implantation for material surface modification research, and good performance has been obtained for the injection of high-current beams of heavy-metal ions, in particular uranium, into particle accelerators. As the use of the sourc...

  2. The AGS Booster vacuum systems

    Energy Technology Data Exchange (ETDEWEB)

    Hseuh, H.C.

    1989-01-01

    The AGS Booster is a synchrotron for the acceleration of both protons and heavy ions. The design pressure of low 10{sup {minus}11} mbar is required to minimize beam loss of the partially stripped heavy ions. To remove contaminants and to reduce outgassing, the vacuum chambers and the components located in them will be chemically cleaned, vacuum fired, baked then treated with nitric oxide. The vacuum sector will be insitu baked to a minimum of 200{degree}C and pumped by the combination of sputter ion pumps and titanium sublimation pumps. This paper describes the design and the processing of this ultra high vacuum system, and the performance of some half-cell vacuum chambers. 9 refs., 7 figs.

  3. The AGS Booster vacuum systems

    International Nuclear Information System (INIS)

    The AGS Booster is a synchrotron for the acceleration of both protons and heavy ions. The design pressure of low 10-11 mbar is required to minimize beam loss of the partially stripped heavy ions. To remove contaminants and to reduce outgassing, the vacuum chambers and the components located in them will be chemically cleaned, vacuum fired, baked then treated with nitric oxide. The vacuum sector will be insitu baked to a minimum of 200 degree C and pumped by the combination of sputter ion pumps and titanium sublimation pumps. This paper describes the design and the processing of this ultra high vacuum system, and the performance of some half-cell vacuum chambers. 9 refs., 7 figs

  4. 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

  5. Calculation of the screened self-energy and vacuum-polarization corrections in high-Z lithium-like ions

    International Nuclear Information System (INIS)

    We present results of a calculation of the two-electron self-energy and vacuum-polarization corrections to the 2p1/2 - 2s transition energy in Li-like uranium and bismuth. The calculation is performed to all orders in αZ. (orig.)

  6. Vapor pressure and evaporation rate of certain heat-resistant compounds in a vacuum at high temperatures

    Science.gov (United States)

    Bolgar, A. S.; Verkhoglyadova, T. S.; Samsonov, G. V.

    1985-01-01

    The vapor pressure and evaporation rate of borides of titanium, zirconium, and chrome; and of strontium and carbides of titanium, zirconium, and chrome, molybdenum silicide; and nitrides of titanium, niobium, and tantalum in a vacuum were studied. It is concluded that all subject compounds evaporate by molecular structures except AlB sub 12' which dissociates, losing the aluminum.

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

    Science.gov (United States)

    Berning, D.

    1981-09-01

    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.

  8. A fixed collector employing reversible vee-trough concentrator and a vacuum tube receiver for high temperature solar energy systems

    Science.gov (United States)

    Selcuk, M. K.

    1976-01-01

    A solar heat collection system employing non-tracking reflectors integrated with a fixed vacuum tube receiver which achieves modest year-round concentration (about 2) of the sunlight at low capital costs is discussed. The axis of the vee-trough reflector lies in a east-west direction and requires reversal of the reflector surfaces only twice a year without disturbing the receiver tubes and associated plumbing. It collects most of the diffuse flux. The vacuum tube receiver with selective absorber has no convection losses while radiation and conduction losses are minimal. Significant cost reductions are offered since the vee-trough can be fabricated from inexpensive polished or plastic reflector laminated sheet metal covering 2/3 of the collection area, and only about 1/3 of the area is covered with the more expensive vacuum tube receivers. Thermal and economic performance of the vee-trough vacuum tube system, year-round variation of the concentration factor, incident flux, useful heat per unit area at various operation temperatures and energy cost estimates are presented. The electrical energy cost is estimated to be 77 mills/kWh, and the system construction cost is estimated to be $1140/kWe.

  9. 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.

  10. Research on vacuum insulation for cryocables

    International Nuclear Information System (INIS)

    Vacuum insulation, as compared with solid insulation, simplifies the construction of both resistive or superconducting cryogenic cables. The common vacuum space in the cable can furnish thermal insulation between the environment and the cryogenic coolant, provide electrical insulation between conductors, and establish thermal isolation between go- and return-coolant streams. The differences between solid and vacuum high voltage insulation are discussed, and research on the design, materials selection, and testing of vacuum insulated cryogenic cables is described

  11. Integrated structure vacuum tube

    Science.gov (United States)

    Dimeff, J.; Kerwin, W. J. (Inventor)

    1976-01-01

    High efficiency, multi-dimensional thin film vacuum tubes suitable for use in high temperature, high radiation environments are described. The tubes are fabricated by placing thin film electrode members in selected arrays on facing interior wall surfaces of an alumina substrate envelope. Cathode members are formed using thin films of triple carbonate. The photoresist used in photolithography aids in activation of the cathodes by carbonizing and reacting with the reduced carbonates when heated in vacuum during forming. The finely powdered triple carbonate is mixed with the photoresist used to delineate the cathode locations in the conventional solid state photolithographic manner. Anode and grid members are formed using thin films of refractory metal. Electron flow in the tubes is between grid elements from cathode to anode as in a conventional three-dimensional tube.

  12. About Art

    OpenAIRE

    Blich, Baruch

    2001-01-01

    In his article, "About Art," Baruch Blich investigates why is art -- and especially modern art -- so difficult to understand? Why do art objects raise questions as to their status? Why scrutinizing art involves semiotics, philosophy of language, linguistics, epistemology, ontology, and even metaphysics? Why art is interpreted by psychoanalysis as well as by behaviorism and psychology of perception? What anthropology and sociology have to do with art and why do we witness art debated in the co...

  13. State of the art in high-power microwaves: An overview

    Energy Technology Data Exchange (ETDEWEB)

    Swegle, J. [Lawrence Livermore National Lab., CA (United States); Benford, J. [Physics International Co., San Leandro, CA (United States)

    1993-12-01

    In the two decades since the presentation of the first experimental results, the study of high-power microwaves (HPM) has aimed at the production of microwave pulses with ever higher peak power and ever larger energy content. Drawing on the electrical pulsed power and relativistic electron beam technologies, a mix of sources have produced power levels in excess of 1 GW and pulse energies of tens to a thousand joules in both the centimeter and millimeter wavelength ranges. The potential for military applications of such powerful bursts became a major driving force for substantial research programs -- and considerable advancements -- in the United States and the former Soviet Union. The end of the Cold War and a reexamination of national priorities has diminished the momentum of military HPM development in these countries. Nevertheless, the field hasn`t reached its limits, in capability or applicability, and one sees at present a diffusion of the technology across national borders. As examples, one sees commitments in the UK, France, and China to national programs aimed at the exploration of the defensive capabilities of HPM. The purpose of this paper will be to examine the state of the art in HPM at this juncture. We will look at: (1) Peak power production; (2) Pulse energy production and the phenomenon of pulse shortening at high peak power levels; (3) Coherent phasing of multiple high-power sources; (4) Compact HPM source development; and (5) Repetitive operation of sources. We will also briefly mention some emerging applications and offer some concluding thoughts.

  14. Probing charge transport at the single-molecule level on silicon by using cryogenic ultra-high vacuum scanning tunneling microscopy

    OpenAIRE

    Guisinger, Nathan P.; Yoder, Nathan L.; Hersam, Mark C.

    2005-01-01

    A cryogenic variable-temperature ultra-high vacuum scanning tunneling microscope is used for measuring the electrical properties of isolated cyclopentene molecules adsorbed to the degenerately p-type Si(100)-2×1 surface at a temperature of 80 K. Current–voltage curves taken under these conditions show negative differential resistance at positive sample bias, in agreement with previous observations at room temperature. Because of the enhanced stability of the scanning tunneling microscope at c...

  15. "Integration" of the Language Arts and Teacher Training: An Examination of Speech Communication Instruction in High School English Classrooms.

    Science.gov (United States)

    Barnes, Judith A.; Hayes, Andrew F.

    1995-01-01

    Surveys high school English teachers in California. Finds that in many areas English teachers' classroom practices do not conform to the integration curriculum guidelines issued by the state. Finds no systematic trend for teachers with an oral communication background to be integrating the language arts more than teachers without this training.…

  16. High-performance vacuum tubes for more energy efficiency. Building-integrated CPC vacuum tube collectors unite several functions.; Hochleistungs-Vakuumroehren fuer mehr Energieeffizienz. Gebaeudeintegrierte CPC-Vakuumroehren-Kollektoren vereinen mehrere Funktionen

    Energy Technology Data Exchange (ETDEWEB)

    Theiss, Eric

    2013-10-15

    The performance of solar collectors primarily contributes to increased efficiency and reduced operating costs of solar thermal systems. With the use of building-integrated CPC vacuum tube collectors an extremely high energy yield is achieved on a smaller collector gross area. As a building-integrated system solution the CPC facade provide panels in addition to its use as spandrel panels within the glazed buildings not only an architectural design element, but unite as a multifunctional component for several functions. [German] Die Leistungsfaehigkeit der Solarkollektoren traegt primaer zur Effizienzsteigerung und Reduzierung der Betriebskosten einer Solarthermieanlagen bei. Mit dem Einsatz gebaeudeintegrierter CPC-Vakuumroehrenkollektoren wird auf einer kleineren Kollektorbruttoflaeche ein extrem hoher Energieertrag erreicht. Als gebaeudeintegrierte Systemloesung bieten die CPC-Fassadenkollektoren neben dem Einsatz als Bruestungselemente auch innerhalb der verglasten Gebaeuden nicht nur ein architektonisches Gestaltungselement, sondern vereinen als multifunktionaler Bestandteil noch mehrere Funktionen.

  17. Regulating vacuum pump speed with feedback control

    International Nuclear Information System (INIS)

    Considerable energy is wasted by the vacuum pump/motor on dairy farms. The output capacity (m3/min or cfm) of the vacuum pump always exceeds the capacity needed to milk cows and wash pipelines. Vacuum pumps run at full speed and load regardless of actual need for air. Excess air is admitted through a controller. Energy can be saved from electrical demand reduced by regulating vacuum pump speed according to air based on air usage. An adjustable speed drive (ASD) on the motor and controlled based upon air usage, can reduce the energy used by the vacuum pump. However, the ASD unit tested could not maintain vacuum levels within generally accepted guidelines when air usage changed. Adding a high vacuum reserve and a dual vacuum controller between the vacuum pump and the milking pipeline brought vacuum stability within guidelines. The ASD/dual vacuum system can reduce energy consumption and demand by at least 50 percent during milking and provide better vacuum stability than conventional systems. Tests were not run during washing cycles. Using 1990 costs and only the energy saved during milking, the simple payback on investment in new equipment for a 5 hp motor, speed controller and vacuum regulator would be about 5 years

  18. 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)

  19. State-of-the-art and recent developments of high-power gyrotron oscillators

    International Nuclear Information System (INIS)

    brazing techniques are available. Recently, gyrotron oscillators have also been successfully used in materials processing. Such technological applications require gyrotrons with the following parameters: ISM frequency f≥24 GHz, Pout=10-50 kW, CW, η=30%. The present paper reviews recent developments and the state-of-the-art of high-power gyrotron oscillators for fusion plasma and industrial applications

  20. State-of-the-art and recent developments of high-power gyrotron oscillators

    Science.gov (United States)

    Thumm, Manfred

    1999-05-01

    brazing techniques are available. Recently, gyrotron oscillators have also been successfully used in materials processing. Such technological applications require gyrotrons with the following parameters: ISM frequency f⩾24 GHz, Pout=10-50 kW, CW, η=30%. The present paper reviews recent developments and the state-of-the-art of high-power gyrotron oscillators for fusion plasma and industrial applications.

  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. Vacuum Brazing of Accelerator Components

    International Nuclear Information System (INIS)

    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.

  3. The influence of nitrogen pressure on the structure of condensates, obtained at vacuum-arc deposition from high entropy alloy AlCrTiZrNbY

    International Nuclear Information System (INIS)

    The possibilities of structural engineering of vacuum-arc coatings based on the high entropy alloy AlCrTiZrNbY have been studied by means of electron microscopy with energy dispersion element analysis, X-ray diffractometry and microidentation methods. It was found, that the coatings formed by means of vacuum-arc method are two-phase objects. The change of nitrogen pressure from 2.0 centre dot 10-4 to 5.0 centre dot 10-4 Torr during the deposition increases the contents of its atoms in the condensate from 2.7 to 21.62%, and this is accompanied by the transfer from nanocrystallic and claster to nanocrystallic two phase state (combination of bcc and fcc structures) and leads to hardness increase from 6.7 to 7.6 GPa. The observed structure changes are explained by the formation of defects of packaging in fcc crystal lattice at low nitrogen content.

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

    Science.gov (United States)

    Lisnyak, M.; Pipa, A. V.; Gorchakov, S.; Iseni, S.; Franke, St.; Khapour, A.; Methling, R.; Weltmann, K.-D.

    2015-09-01

    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.

  5. 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.

  6. 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...

  7. Design and performance of an ultra-high vacuum scanning tunneling microscope operating at dilution refrigerator temperatures and high magnetic fields.

    Science.gov (United States)

    Misra, S; Zhou, B B; Drozdov, I K; Seo, J; Urban, L; Gyenis, A; Kingsley, S C J; Jones, H; Yazdani, A

    2013-10-01

    We describe the construction and performance of a scanning tunneling microscope 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 performance as typical machines with more modest refrigeration by measuring spectroscopic maps at base temperature both at zero field and in an applied magnetic field. PMID:24182125

  8. 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. PMID:25702992

  9. The state of the art on nuclides separation in high level liquid wastes by Truex process

    International Nuclear Information System (INIS)

    For the advancement of the back-end of nuclear fuel cycle, novel CMPO RUEX process was studied for separating minor actinides from fission products in high level liquid waste using real radioactive solutions from PUREX experiments, so as to support PNC's actinides recycling program using fast reactor. The present PUREX process was also studied to improve the separation of 237Np, 106Ru and 99Tc, the most interfering-natured nuclides in both PUREX and TRUEX processes, by utilizing electrochemistry-based salt-free methods which can eliminate the secondary radioactive waste. The state of the art of separation technologies are described by summarizing the extraction behaviors of nuclides in recent hot counter-current runs using CMPO RUEX process with mild salt-free stripping reagents. The degradation and regeneration characteristics of CMPO/TBP/n-dodecane mixture solvent were also simulated by semi-hot experiments. Several experiments to separate minor actinides and lanthanides from the TRUEX mixture product using aqueous amino-poly-carboxylate complexant, DTPA, resulted in reasonable MA/Ln separation profiles in multiple mixer-settler stages and allowed a unique separation flowsheet adaptable to the TRUEX process to be proposed. Application of electrochemistry to assist both solvent extraction processes, e.g., 'anodic oxidation' to destroy PUREX and TRUEX solvent waste in the presence of electron transfer mediator Age2+ or 'cathodic reduction' for electrolytic extraction of Pd2+, RuNO3+ and 99TcO4- from 3 M nitric acid medium is under study. (authors)

  10. Formation of stress students in the process of notions of martial arts in high school

    Directory of Open Access Journals (Sweden)

    Uskov S.V.

    2013-10-01

    Full Text Available Various aspects of the development of resistance to psychophysiological stress among students in the classroom arts. In the experiment involved 40 students (20 - boys, 20 girls. In the experiment, teaching methods and means of special psychological training in the martial arts. Disclosed the specifics of individual psycho-oriented methodology in the modern system of martial arts. The possibility of its use in physical education classes. It is noted that not all stress are barriers health, and only excessive. The most destructive are excessive psychogenic stresses caused by adverse of psychological factors. Psychogenic stress has a great destructive impact on health. It is a major cause of morbidity students. Recommended didactically well-designed prevention techniques.

  11. Estado da arte da cromatografia gasosa de alta resolução e alta temperatura State of the art of high temperature high resolution gas chromatography

    OpenAIRE

    Alberto dos Santos Pereira; Francisco Radler de Aquino Neto

    2000-01-01

    The developments in stationary phase synthesis and capillary column technology, have opened new perspectives in analysis of high molecular mass compounds (³600 daltons) and thermolabile organic compounds by High Temperature High Resolution Gas Chromatography (HT-HRGC). HT-HRGC is a new analytical borderline and its application to the analysis of high molecular mass compounds is still in its infancy. The apolar and medium polar gum phases can now be operated at temperatures up to 400-480º...

  12. 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.

  13. The electrical resistance of vacuum

    Science.gov (United States)

    Bringuier, E.

    2013-07-01

    This paper deals with the physics of electrical conduction in vacuum between two parallel conducting planes (planar vacuum diode). After reviewing known features of conduction in the high-voltage range, we turn to the low-voltage range. An ohmic current-voltage characteristic is calculated in the case of identical cathodic and anodic electrodes, whence an electrical resistance of the vacuum gap can be defined. The inverse resistance involves the elemental conductance 2e 2/h and the number of conductance channels between the two electrodes. The channels are thermally populated from the electrodes and the population is analytically calculable from the Poisson equation of electrostatics and the Boltzmann law of thermal equilibrium. The observed resistance of a real vacuum diode (Mullard's EB 91) is accounted for without adjusting parameters. The paper also examines the link-up between Joule's law, involving dissipation, and Ohm's law, with vacuum being contrasted with a material conducting medium; the origin of dissipation in vacuum is understood. Quantum and statistical physics are kept at the undergraduate level. Finally, the results obtained for the vacuum diode shed light upon the quantized conductance of nanoscale semiconductor wires, a topic usually handled only in graduate courses.

  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. PMID:26735865

  15. Art Imitating Art

    Directory of Open Access Journals (Sweden)

    Eric Brook

    2008-01-01

    Full Text Available Using as a contextual reference my experience of seeing the original and copy of Michelangelo's David in Florence, I briefly introduce how the Platonic legacy has affected that discourse. The Western preference in art and aesthetics is typically in favor of the original over the copy, despite whatever indiscernibility may exist between them. Since Arthur Danto has treated this phenomenon in his text The Transfiguration of the Commonplace, his relevant comments are considered and adapted for the purpose of working through how one understands the relationship between the original and copy in terms of a criterion for defining art.

  16. MEA vacuum system

    International Nuclear Information System (INIS)

    This report describes construction and operation of the MEA vacuum system of NIKHEF (Netherlands). First, the klystron vacuum system, beam transport system, diode pump and a triode pump are described. Next, the isolation valve and the fast valves of the vacuum system are considered. Measuring instruments, vacuum system commands and messages of failures are treated in the last chapter. (G.J.P.)

  17. State-of-the-Art Highly Insulating Window Frames - Research and Market Review

    Energy Technology Data Exchange (ETDEWEB)

    Gustavsen, Arild; Jelle, Bjorn Petter; Arasteh, Dariush; Kohler, Christian

    2007-01-01

    This document reports the findings of a market and research review related to state-of-the-art highly insulating window frames. The market review focuses on window frames that satisfy the Passivhaus requirements (window U-value less or equal to 0.8 W/m{sup 2}K ), while other examples are also given in order to show the variety of materials and solutions that may be used for constructing window frames with a low thermal transmittance (U-value). The market search shows that several combinations of materials are used in order to obtain window frames with a low U-value. The most common insulating material seems to be Polyurethane (PUR), which is used together with most of the common structural materials such as wood, aluminum, and PVC. The frame research review also shows examples of window frames developed in order to increase the energy efficiency of the frames and the glazings which the frames are to be used together with. The authors find that two main tracks are used in searching for better solutions. The first one is to minimize the heat losses through the frame itself. The result is that conductive materials are replaced by highly thermal insulating materials and air cavities. The other option is to reduce the window frame area to a minimum, which is done by focusing on the net energy gain by the entire window (frame, spacer and glazing). Literature shows that a window with a higher U-value may give a net energy gain to a building that is higher than a window with a smaller U-value. The net energy gain is calculated by subtracting the transmission losses through the window from the solar energy passing through the windows. The net energy gain depends on frame versus glazing area, solar factor, solar irradiance, calculation period and U-value. The frame research review also discusses heat transfer modeling issues related to window frames. Thermal performance increasing measures, surface modeling, and frame cavity modeling are among the topics discussed. The

  18. A Web-Based Peer-Assessment Approach to Improving Junior High School Students' Performance, Self-Efficacy and Motivation in Performing Arts Courses

    Science.gov (United States)

    Hsia, Lu-Ho; Huang, Iwen; Hwang, Gwo-Jen

    2016-01-01

    In this paper, a web-based peer-assessment approach is proposed for conducting performing arts activities. A peer-assessment system was implemented and applied to a junior high school performing arts course to evaluate the effectiveness of the proposed approach. A total of 163 junior high students were assigned to an experimental group and a…

  19. Development of gas-fired vacuum furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Sikirica, S.J. (Gas Research Inst. (United States)); Hemsath, K.H. (Indugas Inc. (United States)); Panahi, S.K. (Southern California Gas Co. (United States))

    1994-01-01

    Vacuum processing in metallurgical heat treating processes is finding widespread acceptance. Gas-fired vacuum furnaces have several features that make them perform differently from electrically heated vacuum furnaces. This paper describes the development and preliminary performance results of a gas-fired vacuum-capable furnace system. A gas-fired vacuum furnace, with a novel high convection heating system, is show to result in lower energy operating cost and improved temperature uniformity in processes such as ion nitriding. Industrial gas-fired furnace designs, capable of operation to 1850 F, are described for horizontal and vertical configurations. (orig.)

  20. Language Arts Practices in the Instruction of Oral Communication in California High Schools.

    Science.gov (United States)

    Barnes, Judith A.; Hayes, Andrew F.

    1995-01-01

    Expresses concern with the trend in K-12 education to subsume oral communication programs under the rubric of language arts in English departments. Uses California as a case study to examine whether English teachers are integrating speech communication into the English classroom. Finds that little direct instruction in communication principles and…

  1. 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

  2. Very-Low-Cost, Rugged Vacuum System

    Science.gov (United States)

    Kline-Schoder, Robert; Sorensen, Paul; Passow, Christian; Bilski, Steve

    2013-01-01

    NASA, DoD, DHS, and commercial industry have a need for miniaturized, rugged, low-cost vacuum systems. Recent advances in sensor technology have led to the development of very small mass spectrometer detectors as well as other miniature analytical instruments. However, the vacuum systems to support these sensors remain large, heavy, and power-hungry. To meet this need, a miniaturized vacuum system was created based on a very small, rugged, and inexpensive- to-manufacture molecular drag pump (MDP). The MDP is enabled by the development of a miniature, veryhigh- speed, rugged, low-power, brushless DC motor optimized for wide temperature operation and long life. Such a pump represents an order-of-magnitude reduction in mass, volume, and cost over current, commercially available, state-ofthe- art vacuum pumps. The vacuum system consists of the MDP coupled to a ruggedized rough pump (for terrestrial applications or for planets with substantial atmospheres). The rotor in the MDP consists of a simple smooth cylinder of aluminum spinning 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 motor. The compressed gas then flows down channels in the motor housing to the exhaust port of the pump. The exhaust port of the pump is connected to a diaphragm or scroll pump. This pump delivers very high performance in a very small envelope. The design was simplified so that a smaller compression ratio, easier manufacturing process, and enhanced ruggedness can be achieved at the lowest possible cost. The machining of the rotor and stators is very simple compared to that necessary to fabricate TMP

  3. Fabrication of a Zinc Aluminum Oxide Nanowire Array Photoelectrode for a Solar Cell Using a High Vacuum Die Casting Technique

    OpenAIRE

    Chin-Guo Kuo; Jung-Hsuan Chen; Yueh-Han Liu

    2014-01-01

    Zinc aluminum alloy nanowire was fabricated by the vacuum die casting. Zinc aluminum alloy was melted, injected into nanomold under a hydraulic pressure, and solidified as nanowire shape. Nanomold was prepared by etching aluminum sheet with a purity of 99.7 wt.% in oxalic acid solution. A nanochannel within nanomold had a pore diameter of 80 nm and a thickness of 40 μm. Microstructure and characteristic analysis of the alumina nanomold and zinc-aluminum nanowire were performed by scanning ele...

  4. Room temperature deposition of highly dense TiO2 thin films by filtered cathodic vacuum arc

    Science.gov (United States)

    Guillén, E.; Heras, I.; Rincón Llorente, G.; Lungwitz, F.; Alcon-Camas, M.; Escobar-Galindo, R.

    2015-08-01

    A systematic study of TiO2 films deposited by dc filtered cathodic vacuum arc (FCVA) was carried out by varying the deposition parameters in a reactive oxygen atmosphere. The influence of the oxygen partial pressure on film properties is analyzed. Composition was obtained by Rutherford backscattering spectroscopy (RBS) measurements, which also allow us to obtain the density of the films. Morphology of the samples was studied by scanning electron microscopy (SEM) and their optical properties by ellipsometry. Transparent, very dense and stoichiometric TiO2 films were obtained by FCVA at room temperature.

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

    OpenAIRE

    Alkhimova Mariya A.; Vovchenko Evgeniy D.; Melekhov Andrey P.; Ramakoti Ravi S.; Savelov Alexander S.; Krapiva Pavel S.; Moskalenko Ilya N.

    2015-01-01

    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 comprehe...

  6. Estado da arte da cromatografia gasosa de alta resolução e alta temperatura State of the art of high temperature high resolution gas chromatography

    Directory of Open Access Journals (Sweden)

    Alberto dos Santos Pereira

    2000-06-01

    Full Text Available The developments in stationary phase synthesis and capillary column technology, have opened new perspectives in analysis of high molecular mass compounds (³600 daltons and thermolabile organic compounds by High Temperature High Resolution Gas Chromatography (HT-HRGC. HT-HRGC is a new analytical borderline and its application to the analysis of high molecular mass compounds is still in its infancy. The apolar and medium polar gum phases can now be operated at temperatures up to 400-480ºC, being used for the analysis of n-alcanes up to C-100, lipids, oligosaccharides, industrial resins, polyglycerols, cyclodextrins, porphyrins, etc. This technique should play a leading role as a powerful tool, for many different analysis types, in multidisciplinary fields of Science.

  7. CERN Accelerator School: A vacuum well filled

    CERN Multimedia

    2006-01-01

    CAS and the ALBA Synchrotron Light Facility (Consortium CELLS) jointly organized a specialized school on 'Vacuum in Accelerators' in Platja d'Aro, Spain from 16 to 24 May, 2006. The last CAS course dedicated to the vacuum was organized in 1999, so there was plenty of ground to cover. The challenging programme proposed a review of the latest state of the art developments in the field and included 36 hours of course work. A one-day excursion to Barcelona was also part of the programme. A record of 93 students of more than 24 nationalities attended the course, not only from Europe and North America, but also from Brazil, China, India, Jordan, Morocco and Taiwan. European industry showed a welcome and solid interest in the school both by sending participants to the course, and by providing a few scholarships for highly deserving young students, who would not otherwise have been able to participate without this support. Feedback from the participants acknowledged the expertise of the lecturers, as well as the ...

  8. Surface Emitting, High Efficiency Near-Vacuum Ultraviolet Light Source with Aluminum Nitride Nanowires Monolithically Grown on Silicon.

    Science.gov (United States)

    Zhao, S; Djavid, M; Mi, Z

    2015-10-14

    To date, it has remained challenging to realize electrically injected light sources in the vacuum ultraviolet wavelength range (∼200 nm or shorter), which are important for a broad range of applications, including sensing, surface treatment, and photochemical analysis. In this Letter, we have demonstrated such a light source with molecular beam epitaxially grown aluminum nitride (AlN) nanowires on low cost, large area Si substrate. Detailed angle dependent electroluminescence studies suggest that, albeit the light is TM polarized, the dominant light emission direction is from the nanowire top surface, that is, along the c axis, due to the strong light scattering effect. Such an efficient surface emitting device was not previously possible using conventional c-plane AlN planar structures. The AlN nanowire LEDs exhibit an extremely large electrical efficiency (>85%), which is nearly ten times higher than the previously reported AlN planar devices. Our detailed studies further suggest that the performance of AlN nanowire LEDs is predominantly limited by electron overflow. This study provides important insight on the fundamental emission characteristics of AlN nanowire LEDs and also offers a viable path to realize an efficient surface emitting near-vacuum ultraviolet light source through direct electrical injection. PMID:26375576

  9. Vacuum system for JAERI AVF cyclotron

    International Nuclear Information System (INIS)

    JAERI AVF cyclotron system has been already constructed to promote the application of advanced radiation technology. This cyclotron system consists of two ion sources, an ion injection line, an AVF cyclotron and eight main beam transport lines. The ultimate pressure in each vacuum section was mainly designed on the basis of the ion beam losses caused by the charge exchange with residual gas. The pressure distributions in whole vacuum sections, which were estimated on the practical arrangement of the vacuum components, showed clearly that the objective ultimate pressure could be attainable. The specification for the vacuum system was fixed up taking into account guiding principles such as clean vacuum, maintenance-free and high reliability, and the details of its final composition were described. We also showed the several results of evacuation curve measurement and residual gas analysis in the cyclotron vacuum chamber, reliability test for the vacuum gauge controller and so on. (author) 55 refs

  10. High Road into the Cloud --- Ni Yun-lin's Art of Painting and Its Cultural Value

    Directory of Open Access Journals (Sweden)

    Qiuli Yu

    2010-01-01

    Full Text Available Ni Yun-lin, Painter in the Yuan Dynasty, had great influences in the history of Chinese painting, especially the history of painting of man-of-letters. He stepped over the spatio-temporal limitation and guided trend of painting of man-of-letters several hundred years later. Although he was familiar with Confucianism, Buddhism and Taoism, and was endowed with a kind, sentimental and sincere heart, the abnormality of political ruling of Meng and Yuan Dynasty together with his obstinate and unruly character determined since his birth his destiny --- living in seclusion. He re-organized the value system of human being and established a virtual spiritual homeland. His art of painting was a monument which stood like a giant at the top of the world ethnic arts, with an intangible, cold, secluded and lonely style of painting. It was Ni Yun-lin who pushed the quality of painting to perfection which was most impressive.

  11. Development of vacuum brazing furnace

    International Nuclear Information System (INIS)

    In joining of components where welding process is not possible brazing processes are employed. Value added components, high quality RF systems, UHV components of high energy accelerators, carbide tools etc. are produced using different types of brazing methods. Furnace brazing under vacuum atmosphere is the most popular and well accepted method for production of the above mentioned components and systems. For carrying out vacuum brazing successfully it is essential to have a vacuum brazing furnace with latest features of modern vacuum brazing technology. A vacuum brazing furnace has been developed and installed for carrying out brazing of components of copper, stainless steel and components made of dissimilar metals/materials. The above furnace has been designed to accommodate jobs of 700mm diameter x 2000mm long sizes with job weight of 500kgs up to a maximum temperature of 1250 degC at a vacuum of 5 x 10-5 Torr. Oil diffusion pumping system with a combination of rotary and mechanical booster pump have been employed for obtaining vacuum. Molybdenum heating elements, radiation shield of molybdenum and Stainless Steel Grade 304 have been used. The above furnace is computer controlled with manual over ride facility. PLC and Pentium PC are integrated together to maneuver steps of operation and safety interlocks of the system. Closed loop water supply provides cooling to the system. The installation of the above system is in final stage of completion and it will be ready for use in next few months time. This paper presents insights of design and fabrication of a modern vacuum brazing furnace and its sub-system. (author)

  12. 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.

  13. 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

    and gas sampling device over the sample surface. The gas sampled is analyzed with mass spectrometry. Experiments can be made at pressures up to 1 bar and temperatures up to 500 °C. It is shown that the lateral resolution is better than 0.2 mm and that up to 20 circular spots, 1 mm in diameter, can 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....

  14. The RHIC vacuum systems

    Science.gov (United States)

    Burns, R.; Hseuh, H. C.; Lee, R. C.; McIntyre, G.; Pate, D.; Smart, L.; Sondericker, J.; Weiss, D.; Welch, K.

    2003-03-01

    There are three vacuum systems in RHIC: the insulating vacuum vessels housing the superconducting magnets, the cold beam tubes surrounded by the superconducting magnets, and the warm beam tube sections at the insertion regions and the experimental regions. These systems have a cumulative length over 10 km and a total volume over 3000 m 3. Conventional ultrahigh vacuum technology was used in the design and construction of the cold and warm beam vacuum systems with great success. The long and large insulating vacuum volumes without vacuum barriers require careful management of the welding and leak checking of the numerous helium line joints. There are about 1500 vacuum gauges and pumps serial-linked to eight PLCs distributed around RHIC, which allow the monitoring and control of these devices through Ethernet networks to remote control consoles. With the exception of helium leaks through the cryogenic valve boxes into the insulating vacuum volumes, the RHIC vacuum systems have performed well beyond expectations.

  15. The evaluation of popular music in the United States, Germany and the Netherlands: a comparison of the use of high art and popular aesthetic criteria

    NARCIS (Netherlands)

    A. van Venrooij; V. Schmutz

    2010-01-01

    Popular music has apparently gained much in status and artistic legitimacy. Some have argued that popular music criticism has assimilated the evaluative criteria traditionally associated with high art aesthetics to legitimate pop music as a serious art form, while others have claimed that popular mu

  16. ITER diagnostic system: Vacuum interface

    International Nuclear Information System (INIS)

    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 10−7 Pa, irrespective of plasma operation, and a leak rate of less than 10−10 Pa m3 s−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 will be described

  17. The response to high magnetic fields of the vacuum phototriodes for the Compact Muon Solenoid endcap electromagnetic calorimeter

    International Nuclear Information System (INIS)

    The endcap electromagnetic calorimeter of the compact muon solenoid detects particles with the dense fast scintillator lead tungstate (PbWO4). Due to the low light yield of this scintillator, photodetectors with internal gain are required. Silicon avalanche photodiodes cannot be used in the endcap region due to the intense neutron flux. Following an extensive R and D programme, 26 mm diameter single-stage photomultipliers (vacuum phototriodes) have been chosen as the photodetector in the endcap region. The first 1400 production devices are currently being evaluated following recent tests of a pre-production batch of 500 tubes. Tubes passing our acceptance tests have responses, averaged over the angular acceptance of the endcap calorimeter, corresponding to the range 20-55 electrons/MeV deposited in PbWO4. These phototriodes operate, with a typical gain of 10, in magnetic fields up to 4 T

  18. Technical specification for vacuum systems

    International Nuclear Information System (INIS)

    The vacuum systems at the Stanford Linear Accelerator Center (SLAC) are primarily of all-metal construction and operate at pressures from 10-5 to 10-11 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

  19. 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)

  20. Vacuum arc under axial magnetic fields: experimental and simulation research

    International Nuclear Information System (INIS)

    Axial magnetic field (AMF) technology is a most important control method of vacuum arc, particularly for high-current vacuum arcs in vacuum interrupters. In this paper, a review of the state of current research on vacuum arcs under AMF is presented. The major aspects of vacuum arc in an AMF such as arc voltage, the motion of cathode spots, and anode activities are discussed, and the most recent progress both of experimental and simulation research is presented. (topical review)

  1. Influence of Gap Distance on Vacuum Arc Characteristics of Cup Type AMF Electrode in Vacuum Interrupters

    Science.gov (United States)

    Cheng, Shaoyong; Xiu, Shixin; Wang, Jimei; Shen, Zhengchao

    2006-11-01

    The greenhouse effect of SF6 is a great concern today. The development of high voltage vacuum circuit breakers becomes more important. The vacuum circuit breaker has minimum pollution to the environment. The vacuum interrupter is the key part of a vacuum circuit breaker. The interrupting characteristics in vacuum and arc-controlling technique are the main problems to be solved for a longer gap distance in developing high voltage vacuum interrupters. To understand the vacuum arc characteristics and provide effective technique to control vacuum arc in a long gap distance, the arc mode transition of a cup-type axial magnetic field electrode is observed by a high-speed charge coupled device (CCD) video camera under different gap distances while the arc voltage and arc current are recorded. The controlling ability of the axial magnetic field on vacuum arc obviously decreases when the gap distance is longer than 40 mm. The noise components and mean value of the arc voltage significantly increase. The effective method for controlling the vacuum arc characteristics is provided by long gap distances based on the test results. The test results can be used as a reference to develop high voltage and large capacity vacuum interrupters.

  2. C-O relations of the extremely low carbon austenitic stainless steels and nickel base high alloys in vacuum induction melting

    International Nuclear Information System (INIS)

    It is well known that in vacuum-melted austenitic stainless steel and nickel base alloy, the impurities of minute amounts affect adversely the corrosion resistance and high temperature strength. Therefore the materials of high quality, such as those in extremely low carbon range below 0.01%, are required in nuclear and chemical plants. In this study, austenitic stainless steel such as SUS 308, 309 and 316 and nickel base alloy such as Ni-20 Cr-2.6 Nb and Ni-20 Mo-3W were melted in a 200 kg vacuum induction furnace, and the behaviors of C and O during the refining were investigated, also the thermodynamical analysis was performed. For comparison, pure iron was studied at the same time. The amounts of C and O were reduced from the beginning of melting through intensive boiling period, and when quiescent period was reached, the equilibrium relation of C and O was able to be applied also to the case of austenitic stainless steel. In case of the nickel base alloy, it was presumed that the relation of C and O in quiescent period of molten alloy was near the equilibrium state. The partial pressure of CO in the stainless steel was low as compared with the pure iron, because the effect of refractory material to the oxygen potential of molten steel is different according to the steel composition. (auth.)

  3. A low temperature ultrahigh vacuum scanning tunneling microscope with high-NA optics to probe optical interactions at the atomic scale

    Science.gov (United States)

    Zhang, Haigang; Smerdon, Joseph; Suzer, Ozgun; Kersell, Heath; Guest, Jeffrey

    2015-03-01

    The optical and photophysical properties of single molecules/atoms, defects, and nanoscale structures at surfaces hinge on structure at the atomic scale. In order to characterize and control this structure and unravel these correlations, we are developing a low temperature (LT) laser-coupled ultrahigh vacuum (UHV) scanning tunneling microscope (LT Laser UHV STM) based on the Pan-style STM scanner with integrated high-numerical-aperture (NA) optics for single particle spectroscopy measurements under the STM tip. Using slip-stick inertial piezo steppers, the sample stage can be coarsely translated in X and Y directions. For optical measurements, high-NA optics behind and above the sample focus laser excitation on and collect photons emitted from the tip-sample junction. The STM is cooled by a liquid helium bath surrounded by a liquid nitrogen jacket for operation near 5 K; two separate ultrahigh vacuum chambers are used for sample preparation and STM measurements, respectively. We will describe our progress in demonstrating this instrument and plans for experiments studying the correlation between structure and optical function in nanoscale systems. U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences.

  4. 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 ...

  5. Microstructure of X210Cr12 steel after the forming in semi-solid state visualized by very low energy SEM in ultra high vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Mikmeková, Š., E-mail: sarka@isibrno.cz [Institute of the Scientific Instruments of the ASCR, v.v.i., Královopolská 147, Brno 612 64 (Czech Republic); Mašek, B.; Jirková, H.; Aišman, D. [University of West Bohemia in Pilsen, Research Centre of Forming Technology – FORTECH, Univerzitni 22, 306 14 Pilsen (Czech Republic); Müllerová, I.; Frank, L. [Institute of the Scientific Instruments of the ASCR, v.v.i., Královopolská 147, Brno 612 64 (Czech Republic)

    2013-06-15

    Progress in materials science is inseparably connected with development of new analytical methods which make possible to observe the materials microstructure with high sensitivity. The aim of the present study is shown that scanning low energy electron microscopy (SLEEM) has a significant impact in advance of a fundamental understanding of the evolution of microstructure upon semi-solid processing. This paper deals with the application of the ultra high vacuum scanning low energy electron microscopy (UHV SLEEM) to the study of microstructure of X210Cr12 steel after the formation in semi-solid state and the study of the annealing of deformed metastable austenite. Examples from these specimens show that the contrast between differently oriented grains in polycrystalline materials is very sensitive to the parameters such as energy of the primary beam, working distance and detection of high angle backscattered electrons.

  6. Physical characteristics, structure and stress state of vacuum-arc TiN coating, deposition on the substrate when applying high-voltage pulse during the deposition

    International Nuclear Information System (INIS)

    Method of vacuum-arc deposition with ion implantation, (mode PBIID) obtained by coating of titanium nitride with a hardness of 62 GPa and reaches a high resistance to wear during the cutting. Submission of high-voltage pulses results in the formation of a stable structural state of titanium with cubic mononitride (structural type NaCl) crystal lattice. Comparison of the structure and stress state of titanium nitride coatings obtained in the usual way without additional supply of high-voltage pulses to the substrate during the deposition and the imposition of such pulses, shows that the influence of the pulse characteristics are a significant decrease in crystallite size and undirected growth at low significance of potential bias on substrate (from the 'floating' around -5 to -40 V), and a significant reduction of internal stresses.

  7. Advanced light source vacuum policy and vacuum guidelines for beamlines and experiment endstations

    International Nuclear Information System (INIS)

    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. Ceramic vacuum tubes for geothermal well logging

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, R.D.

    1977-01-01

    Useful design data acquired in the evaluation of ceramic vacuum tubes for the development of a 500/sup 0/C instrumentation amplifier are presented. The general requirements for ceramic vacuum tubes are discussed for application to the development of high temperature well logs. Commercially available tubes are described and future contract activities that specifically relate to ceramic vacuum tubes are detailed. Supplemental data are presented in the appendix.

  9. Progress in vacuum metal extraction, refining and consolidation

    International Nuclear Information System (INIS)

    The unique achievements in the process metallurgy of rare metals in the past quarter century should largely be attributed to advances in vacuum technology. New standards for high purity, increasing demand for pure metals and alloys for established applications, and steady improvement in sophistication and capacity of vacuum furnaces have provided the stimulus for developing and expanding vacuum metal extraction processes, and also exploring totally new processes. The paper discusses the thermochemistry of vacuum metallurgy, carbothermic and metallothermic reduction reactions, consolidation and refining by vacuum arc melting, electron beam melting and high temperature high vacuum sintering, and ultrapurification, with special reference to the reactive and refractory metals of Group IV to VI. (author)

  10. The art of scent

    DEFF Research Database (Denmark)

    Stenslund, Anette

    2016-01-01

    At the Museum of Art and Design in New York the The Art of Scent (1889–2012) exhibition announced its declared aim of bringing to the forefront of the arts what has long been considered the fallen angel of the senses: it would inscribe scent into fine art through a display characterised by its ex...... situ superiority detached from everyday culture in situ. The exhibition would thus give cause to sketch in a phenomenology of the art of scent that opts for greater inclusion of visitors’ experienced noses. Unfolding within the framework of Martin Heidegger’s critique of aesthetics and the advocacy of...... art, this paper argues that scent that is not of high culture may yet, phenomenologically speaking, be considered great art....

  11. 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...

  12. A suggestion of the graphene/Ge(111) structure based on ultra-high vacuum scanning tunneling microscopy investigation

    International Nuclear Information System (INIS)

    We report on the 5.5√3x5.5√3- R300 overlayers superstructure observed by the scanning tunneling microscopy on the Ge(111) surface. It shows pronounced effects of the local density of states leading to the strong dependence of STM images on the bias voltage and some dynamic changes of images at 300 K. This overlayer is tentatively interpreted as graphene formed in small submonolayer amounts due to the pyrolysis of hydrocarbon constituents of the residual atmosphere of the vacuum chamber during the annealing of a Ge(111) sample at 900 K. We suggest a model of the graphene/Ge(111)- 5.5 √3x5.5√3-R300. Heteroepitaxial interface, featuring the reconstructed Ge(111) substrate with no long-range order under the graphene layer, the latter being corrugated due to spatial variations of the interatomic geometry of the Ge(111) and graphene(0001) atomic lattices with extremely large mismatch

  13. Signal Processing in High-End Hearing Aids: State of the Art, Challenges, and Future Trends

    Science.gov (United States)

    Hamacher, V.; Chalupper, J.; Eggers, J.; Fischer, E.; Kornagel, U.; Puder, H.; Rass, U.

    2005-12-01

    The development of hearing aids incorporates two aspects, namely, the audiological and the technical point of view. The former focuses on items like the recruitment phenomenon, the speech intelligibility of hearing-impaired persons, or just on the question of hearing comfort. Concerning these subjects, different algorithms intending to improve the hearing ability are presented in this paper. These are automatic gain controls, directional microphones, and noise reduction algorithms. Besides the audiological point of view, there are several purely technical problems which have to be solved. An important one is the acoustic feedback. Another instance is the proper automatic control of all hearing aid components by means of a classification unit. In addition to an overview of state-of-the-art algorithms, this paper focuses on future trends.

  14. Signal Processing in High-End Hearing Aids: State of the Art, Challenges, and Future Trends

    Directory of Open Access Journals (Sweden)

    U. Rass

    2005-11-01

    Full Text Available The development of hearing aids incorporates two aspects, namely, the audiological and the technical point of view. The former focuses on items like the recruitment phenomenon, the speech intelligibility of hearing-impaired persons, or just on the question of hearing comfort. Concerning these subjects, different algorithms intending to improve the hearing ability are presented in this paper. These are automatic gain controls, directional microphones, and noise reduction algorithms. Besides the audiological point of view, there are several purely technical problems which have to be solved. An important one is the acoustic feedback. Another instance is the proper automatic control of all hearing aid components by means of a classification unit. In addition to an overview of state-of-the-art algorithms, this paper focuses on future trends.

  15. Realisation of a ultra-high vacuum system and technique development of microscopical emitters preparation in silicium. First measurements of field emission current and field photoemission

    International Nuclear Information System (INIS)

    The development of research in the domain of photocathode (electron sources) illuminated by laser light to produce intense multiple bunches of electrons in short time is needed by many applications as linear collider e+e-, free electron laser, lasertron, etc... In this way, after a study of field emission, of photoemission and of photofield emission, we prepared microscopical emitters in silicium heavy and weakly doped a boron using a technique of microlithography. Then, we realized a system of ultra-high vacuum of studying property of emission from photocathodes realized. The experiment results obtained in field emission and photofield emission have shown that a behaviour unexpected for P-silicium tips array compared to P+-silicon tips array. With P-type silicon, a quantum yield of 21 percent has been measured for laser power of 140 mW and for applied field of 1.125 x 107 V/m and an instantaneous response to laser light beam has been observed. It has been noted that presence of oxyde at the surface of photocathode limits extensively the emission current. The fluctuations of emission current are due to quality of vacuum

  16. Effect of surface oxide layers on deuterium permeation through stainless steels with reference to outgassing reduction in ultra-to extremely high vacuum

    International Nuclear Information System (INIS)

    Hydrogen is a dominant outgassing species from stainless steel vacuum chambers in ultra-to extremely high vacuum. Oxidation of stainless steel surfaces has been known to reduce the outgassing. The oxide layer formed on the stainless steel surface is expected to serve as a diffusion barrier for hydrogen diffusing from the bulk. In the present study the effects of oxidation on the outgassing rate, on hydrogen thermal desorption spectra, on surface contamination and on deuterium permeation and diffusion characteristics through the stainless steels are summarized. Discussion is given to the role of the surface oxide layer in outgassing reduction as well as to the effect of thickness and chemical compositions on reduction in hydrogen permeability and diffusion. The surface oxide formed in the present study appears to serve as the diffusion barrier for hydrogen and is found to decrease the deuterium permeability to 1/2-1/3 of the unoxidized one by lowering the diffusion coefficient. The most effective oxide is proposed to be Cr-rich oxide with 100-200 ''A'' thickness. (Author)

  17. Novel multi-beam X-ray source for vacuum electronics enabled medical imaging applications

    Science.gov (United States)

    Neculaes, V. Bogdan

    2013-10-01

    For almost 100 of years, commercial medical X-ray applications have relied heavily on X-ray tube architectures based on the vacuum electronics design developed by William Coolidge at the beginning of the twentieth century. Typically, the Coolidge design employs one hot tungsten filament as the electron source; the output of the tube is one X-ray beam. This X-ray source architecture is the state of the art in today's commercial medical imaging applications, such as Computed Tomography. Recently, GE Global Research has demonstrated the most dramatic extension of the Coolidge vacuum tube design for Computed Tomography (CT) in almost a century: a multi-beam X-ray source containing thirty two cathodes emitting up to 1000 mA, in a cathode grounded - anode at potential architecture (anode up to 140 kV). This talk will present the challenges of the X-ray multi-beam vacuum source design - space charge electron gun design, beam focusing to compression ratios needed in CT medical imaging applications (image resolution is critically dependent on how well the electron beam is focused in vacuum X-ray tubes), electron emitter choice to fit the aggressive beam current requirements, novel electronics for beam control and focusing, high voltage and vacuum solutions, as well as vacuum chamber design to sustain the considerable G forces typically encountered on a CT gantry (an X-ray vacuum tube typically rotates on the CT gantry at less than 0.5 s per revolution). Consideration will be given to various electron emitter technologies available for this application - tungsten emitters, dispenser cathodes and carbon nano tubes (CNT) - and their tradeoffs. The medical benefits potentially enabled by this unique vacuum multi-beam X-ray source are: X-ray dose reduction, reduction of image artifacts and improved image resolution. This work was funded in part by NIH grant R01EB006837.

  18. 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.

  19. Cryogenic tritium-hydrogen-deuterium and deuterium-tritium layer implosions with high density carbon ablators in near-vacuum hohlraums

    Science.gov (United States)

    Meezan, N. B.; Berzak Hopkins, L. F.; Le Pape, S.; 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.; Izumi, N.; Kyrala, G. A.; Moody, J. D.; Patel, P. K.; Ralph, J. E.; Rygg, J. R.; Sepke, S. M.; Spears, B. K.; Tommasini, R.; Town, R. P. J.; Biener, J.; Bionta, R. M.; Bond, E. J.; Caggiano, J. A.; Eckart, M. J.; Gatu Johnson, M.; Grim, G. P.; Hamza, A. V.; Hartouni, E. P.; Hatarik, R.; Hoover, D. E.; Kilkenny, J. D.; Kozioziemski, B. J.; Kroll, J. J.; McNaney, J. M.; Nikroo, A.; Sayre, D. B.; Stadermann, M.; Wild, C.; Yoxall, B. E.; Landen, O. L.; Hsing, W. W.; Edwards, M. J.

    2015-06-01

    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 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 × 1015 neutrons, 40% of the 1D simulated yield.

  20. Car Art.

    Science.gov (United States)

    Meilach, Dona Z.

    2002-01-01

    Discusses car art and its appeal to boys and girls. Describes the popularity of customizing cars, focusing on this as a future career for students. Includes a list of project ideas that focuses on car art. (CMK)

  1. Street art

    OpenAIRE

    Mulcahy, Linda

    2014-01-01

    This film considers what collectors lose when they take street art away from the street. More generally, it looks at the challenges posed by street art and the way it encourages us to reclaim our city.

  2. Organisational Art

    DEFF Research Database (Denmark)

    Ferro-Thomsen, Martin

    the boundaries of the art institution ? and thereby expanding it without suspending it. The thesis takes its historical outset with ?Artist Placement Group? (formed in 1966), a British art group that developed an unprecedented framework for placing artists in organisational environments to circumvent......University of Copenhagen / Learning Lab Denmark. 2005 Kort beskrivelse: Organisational Art is a tentative title for an art form that works together with organisations to produce art. This is most often done together with non-artist members of the organisation and on-site in their social context. OA...... is characterised as socially engaged, conceptual, discursive, site-specific and contextual. Abstract: This investigation is about Organisational Art (OA), which is a tentative title for an art form that works together with organisations (companies, institutions, communities, governments and NGOs) to produce art...

  3. Ceramic vacuum tubes for geothermal well logging

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, R.D.

    1977-01-12

    The results of investigations carried out into the availability and suitability of ceramic vacuum tubes for the development of logging tools for geothermal wells are summarized. Design data acquired in the evaluation of ceramic vacuum tubes for the development of a 500/sup 0/C instrumentation amplifier are presented. The general requirements for ceramic vacuum tubes for application to the development of high temperature well logs are discussed. Commercially available tubes are described and future contract activities that specifically relate to ceramic vacuum tubes are detailed. Supplemental data is presented in the appendix. (MHR)

  4. Vacuum polarization in Schwarzschild spacetime: Boulware vacuum

    International Nuclear Information System (INIS)

    Approximate regularized expectation values of the field fluctuation (Φ2)reg and the stress-energy tensor (Tμν)reg of the massless, conformally invariant, scalar field in the Boulware vacuum state in Schwarzschild spacetime are constructed by means of Hadamard regularization. It is shown that reconstruction of the characteristics of the vacuum polarization from its asymptotic behaviour leads to formulas that satisfactorily reproduce existing approximate expressions and closely follow exact numerical calculations. (author)

  5. 高压电机定子VPI浸漆渗透性分析%Permeability Analysis of High Voltage Motor Stator Vacuum Pressure Impregnating

    Institute of Scientific and Technical Information of China (English)

    任科; 邓灿华; 王晓群; 周杏军; 钟军

    2016-01-01

    高压电机定子线圈的绝缘层较厚,在VPI浸漆过程中,浸渍漆渗入线圈内部越充分,浸漆后云母带与浸渍漆形成绝缘体越紧密,电气强度也越大;反之,若浸渍漆未充分渗入线圈内部,极易引起浸漆后定子对地耐压击穿。本文通过验证并分析浸漆过程真空度、浸漆压力、保压时间、云母带与浸渍漆的相容性、浸漆液面高度等因素对高压电机定子线圈浸渍漆渗透性影响,提出了改善线圈绝缘漆渗透性的工艺措施,有效解决了高压电机浸漆后定子耐压击穿的问题。%High-voltage motor stator coil insulation is thick, in the process of vacuum pressure impregnating, the more varnish impregnated into the coil, the more closely insulation formed by MICA tape and varnish after vacuum pressure impregnating, the electric strength is greater. On the contrary, if the varnish was not fully penetrated into the coil, can easily lead to stator breakdown in the voltage withstand test after vacuum pressure impregnating. By tested and analyzed impregnation pressure, holding time, the compatibility between MICA tapes and varnish, the height of varnish and other factors influence on permeability of high-voltage motor stator coil in the impregnating process, proposed measures to improve the permeability of coil, effectively solve the problem of high voltage motor stator breakdown in the voltage withstand test after the impregnating.

  6. 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

  7. 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 ...

  8. 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.

  9. Vacuum brazing of metals (1961)

    International Nuclear Information System (INIS)

    We have studied brazing in vacuum aiming its application for the making of containers and apparatus meant for high vacuum (p -8 torr). We first define the wettability of a brazing alloy on a metal and we remind the influence of the various parameters which act on this wettability (nature of the solid, of the liquid, geometrical and physicochemical state of the surface, metallurgical reactions occurring at the interface, temperature, time). We give then the results of the tests carried out in order to determine the conditions of wettability in vacuum of some brazing alloys on metals which can be used for the above mentioned apparatus (stainless steel, aluminium, bronze, titanium, zirconium, kovar, nickel, copper). (author)

  10. A compact Ultra-High Vacuum (UHV) compatible instrument for time of flight-energy measurements of slow heavy reaction products

    International Nuclear Information System (INIS)

    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 ∼35 keV/nucleon from the interactions of 400 MeV/nucleon 16O with natXe gas targets

  11. Effect of high-k and vacuum dielectrics as gate stack on a junctionless cylindrical surrounding gate (JL-CSG) MOSFET

    Science.gov (United States)

    Sharma, Aniruddh; Jain, Arushi; Pratap, Yogesh; Gupta, R. S.

    2016-09-01

    In this paper, the impact of asymmetric gate stack architecture using a combination of vacuum and high-k dielectrics on a junctionless cylindrical surrounding gate (JL-CSG) MOSFET has been investigated. A comparative evaluation of short channel effects (SCEs) for various device structures has also been carried out with figure of merit (FOM) metrics such as electric field, electron temperature, drain current (Ids), and drain induced barrier lowering (DIBL). A two-dimensional analytical model has been developed for the asymmetric architecture using Poisson's equation in cylindrical coordinates assuming a parabolic potential profile. It is observed that the asymmetric gate stack device demonstrates effectiveness in suppressing hot carrier degradation and short channel effects along with improving the current drivability of the device as compared to the other device configurations. The analytical results have been verified with the simulated data obtained from ATLAS 3-D device simulator.

  12. 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.

  13. The Relationships among the Fine Arts, School Culture, and High School Graduation Rates in Georgia

    Science.gov (United States)

    Lovett, Andrew, Jr.

    2014-01-01

    High school graduation is the single largest hurdle that students must achieve to prepare for college and career (National Governor's Association, 2011). Fleischman & Heppen (2009) agree that American high schools must address the problem of declining graduation rate. Approximately 1.28 million students drop out of high school annually (Amos,…

  14. State of the art and trends of high-Tc superconductivity

    International Nuclear Information System (INIS)

    In this paper a brief account is given on some aspects of the development of high-Tc Superconductivity since the last edition of the SATT Conference. This year significant results have been obtained in the challenging endeavor of increasing high critical current densities and in the context of high-Tc junctions. The attention is confined to achievements and perspectives in these two topics

  15. Quantum vacuum friction

    International Nuclear Information System (INIS)

    The quantum vacuum may in certain circumstances be regarded as a type of fluid medium, or aether, exhibiting energy density, pressure, stress and friction. Vacuum friction may be thought of as being responsible for the spontaneous creation of particles from the vacuum state when the system is non-stationary. Examples include the expanding universe, rotating black holes, moving mirrors, atoms passing close to surfaces, and the activities of sub-cellular biosystems. The concept of vacuum friction will be reviewed and illustrated, and some suggestions for future experiments made

  16. Gravitation and vacuum field

    International Nuclear Information System (INIS)

    This paper presents equations that describe particles with spins s = 0, 1/2, 1 completely and which also describe 2s + 2 limiting fields as E → ∞. It is shown that the ordinary Hilbert-Einstein action for the gravitation field must be augmented by the action for the Bose vacuum field. This means that one must introduce in the gravitational equations a cosmological term proportional to the square of the strength of the Bose vacuum field. It is shown that the theory of gravitation describes three realities: matter, field, and vacuum field. A new form of matter--the vacuum field--is introduced into field theory

  17. 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.

  18. Probing charge transport at the single-molecule level on silicon by using cryogenic ultra-high vacuum scanning tunneling microscopy.

    Science.gov (United States)

    Guisinger, Nathan P; Yoder, Nathan L; Hersam, Mark C

    2005-06-21

    A cryogenic variable-temperature ultra-high vacuum scanning tunneling microscope is used for measuring the electrical properties of isolated cyclopentene molecules adsorbed to the degenerately p-type Si(100)-2x1 surface at a temperature of 80 K. Current-voltage curves taken under these conditions show negative differential resistance at positive sample bias, in agreement with previous observations at room temperature. Because of the enhanced stability of the scanning tunneling microscope at cryogenic temperatures, repeated measurements can be routinely taken over the same molecule. Taking advantage of this improved stability, we show that current-voltage curves on isolated cyclopentene molecules are reproducible and possess negligible hysteresis for a given tip-molecule distance. On the other hand, subsequent measurements with variable tip position show that the negative differential resistance voltage increases with increasing tip-molecule distance. By using a one-dimensional capacitive equivalent circuit and a resonant tunneling model, this behavior can be quantitatively explained, thus providing insight into the electrostatic potential distribution across a semiconductor-molecule-vacuum-metal tunnel junction. This model also provides a quantitative estimate for the alignment of the highest occupied molecular orbital of cyclopentene with respect to the Fermi level of the silicon substrate, thus suggesting that this experimental approach can be used for performing chemical spectroscopy at the single-molecule level on semiconductor surfaces. Overall, these results serve as the basis for a series of design rules that can be applied to silicon-based molecular electronic devices. PMID:15956214

  19. Teaching the Holocaust with Online Art: A Case Study of High School Students

    Science.gov (United States)

    Russell, William Benedict, III

    2007-01-01

    This article examines student's perceptions of using primary sources (online Holocaust artwork) and non-traditional teaching methods in a high school social studies classroom to help students gain a deeper understanding and appreciation for the content. Nine high school students (5 female and 4 male) were studied. Students were interviewed after…

  20. Arte Brasileno Erudito y Arte Brasileno Popular. (Brazilian Fine Art and Brazilian Popular Art)

    Science.gov (United States)

    Valladares, Clarival Do Prado

    1969-01-01

    Class differences in Brazil explain the inequality between the art produced in the high strata of society and that originating in the economically inferior communities. Genuine expression of art degenerates for two reasons: the influence of modern industrial civilization and the tendency to satisfy the taste of the acquisitive group. (Author/MF)

  1. The Art of Education

    Science.gov (United States)

    Abdul-Alim, Jamaal

    2012-01-01

    Dr. Robert F. Sabol, professor of visual and performing arts at Purdue University says that art education has suffered some serious setbacks since No Child Left Behind--the landmark federal education law that put a greater emphasis on high-stakes testing. Since No Child Left Behind became law in 2002, school systems--under increased pressure to…

  2. 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.

  3. The Effect of High-voltage Pulse Potential Applied to the Substrate on the Phase Composition and Structure of the Vacuum-arc TiN Coatings

    Directory of Open Access Journals (Sweden)

    O.V. Sobol

    2015-06-01

    Full Text Available The effect of the high-voltage supply capacity in the form of different pulse duration on the formation of preferentially oriented crystallites and the stress-strain state of the vacuum-arc TiN coatings was analyzed. It is shown that the deposition of coatings in a high-voltage cascade forming exposure leads to the growth of the crystallites with axis texture [110] and the change in the stress-strain state: strengthening of a strain in a group of crystallites with the axis [110] and reduction of the strain in a group of crystallites with axis [111]. The results are explained by the increase in mobility of atoms and streamlining processes in the field of displacement cascades, formed under the influence of high-energy bombarding ions accelerated in the field of high-voltage pulse potential. A generalized graph of the texture type on the pulse potential and influence of the pulse duration, applied to the substrate, on the total deposition time are plotted.

  4. Installation Art

    DEFF Research Database (Denmark)

    Petersen, Anne Ring

    Despite its large and growing popularity – to say nothing of its near-ubiquity in the world’s art scenes and international exhibitions of contemporary art –installation art remains a form whose artistic vocabulary and conceptual basis have rarely been subjected to thorough critical examination....... In Installation Art: Between Image and Stage, Anne Ring Petersen aims to change that. She begins by exploring how installation art developed into an interdisciplinary genre in the 1960s, and how its intertwining of the visual and the performative has acted as a catalyst for the generation of new artistic...... phenomena. It investigates how it became one of today’s most widely used art forms, increasingly expanding into consumer, popular and urban cultures, where installation’s often spectacular appearance ensures that it meets contemporary demands for sense-provoking and immersive cultural experiences. The main...

  5. Vacuum vessel of thermonuclear device

    International Nuclear Information System (INIS)

    An innermost wall joining portion and an outermost wall joining portion are disposed at the innermost and the outermost walls of ribs secured to sector pieces at both ends which constitutes a vacuum vessel, to which first inner wall pieces and first outer wall pieces used for walls of a vacuum vessel at a first stage of assembling are connected. In addition, an inner wall joining portion and an outer wall joining portion are disposed to a portion inner than the innermost and the outermost walls of the rib, to which second inner wall pieces and, outer wall pieces to be used as walls of the vacuum vessel are connected upon reassembling of walls. Since robots can access easily from the inner side of the vacuum vessel, the first inner wall pieces and the outer wall pieces are each connected to the innermost and the outermost wall connection portions upon initial stage of the assembly, and the second inner wall pieces and outer wall pieces are connected to the inner and outer wall connection portions previously fabricated other than cutting portions at high accuracy and high strength upon reassembling of walls. (N.H.)

  6. Vacuum test bench for high-voltage tests of storage chambers in the electric dipole moment spectrometer

    Science.gov (United States)

    Lasakov, M. S.; Polyushkin, A. O.; Serebrov, A. P.; Kolomenskii, E. A.; Pirozhkov, A. N.; Krasnoshchekova, I. A.

    2016-04-01

    We describe the structure of the high-voltage test bench for checking individual insulators and their assemblies with separate control of leakage currents in each insulator. The test bench is mainly intended for preparing the high-voltage block of the spectrometer for the search for the electric dipole moment (EDM) of the neutron. The main part of the bench is the high-voltage source with controllable polarity and voltages up to 200 kV with complex control over parameters. An analogous converter is used in experiment on measuring the EDM of the neutron. We report on the results of testing the new design of the storage chambers of the EDM spectrometer operating with a high voltage; we also test the maximal potentialities of the converter under nearly working conditions; its optimization and calibration are performed.

  7. State-of-the-art report on ultra-high performance concrete (UHPC

    Directory of Open Access Journals (Sweden)

    Gheorghe-Alexandru BĂRBOS

    2014-07-01

    Full Text Available Ultra - High Performance Concrete (UHPC is a special material with compressive strength higher than 150 MPa and an increased durability, which is reflected in its name. It was discovered by Japanese researches in the mid eighties, but since then the study of this material has been expanded all over the world. Besides its high - strength it has an enhanced ductility, due to the presence of steel fibers in the concrete matrix. It can be used as structural material for buildings located in areas with high seismic risk and also in marine or industrial (where chemical attack is possible environments. This type of concrete is still in the research-development stage, no design standard being available.

  8. State of art report for high temperature wear test of SMART MCP and CEDM bearing material

    International Nuclear Information System (INIS)

    Wear resistance properties of machine elements has been more critical in view of its significant effect on life extension, economics and material saving because it has been recognized that nearly 80 percent of damages of mechanical elements in the friction pairs are due to the material loss by wear. And wear properties have direct influence on the life of a machine in a great extend under extremely severe operating condition. Therefore highly improved wear properties of machine elements operating in such circumstances is heavily required. The purpose of this report is to survey current technology for high temperature wear test in order to establish the test plan for the life evaluation of SMART MCP and CEDM bearing materials. Friction and wear test will be done under high pressure (170 MPa) and high temperature (350 degree C) with water as lubricant to simulate the operating condition of the nuclear power reactor. Because pump type for MCP is selected as the caned motor pump which needs no mechanical sealing, the rotating shaft on which bearing is fully submerged by main coolant with high temperature. So MCP bearing operates without additional lubricant. CEDM is adopted as the ball-screw type with fine controllability. So the driving part is designed as the immersed-in type by main coolant. Therefore the anti-wear and reliability of driving parts are much consequent to guarantee the lifetime and the safety of the whole system. Tribometer adapted to high temperature and pressure circumstance is needed to execute bearing material testing. Test parameters are material, sliding speed, sliding distance and applied load. In order to identify the wear mechanism, optical microscope and surface roughness testers are required. The result of this report will provide an elementary data to develop bearing materials and to estimate bearing lifetime for the bearings of MCP and CEDM in SMART. (author)

  9. State of art report for high temperature wear test of SMART MCP and CEDM bearing material

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yong Hu; Lee, Jae Seon; Park, Jin Seok; Kim, Ji Ho; Kim, Jong In

    2000-03-01

    Wear resistance properties of machine elements has been more critical in view of its significant effect on life extension, economics and material saving because it has been recognized that nearly 80 percent of damages of mechanical elements in the friction pairs are due to the material loss by wear. And wear properties have direct influence on the life of a machine in a great extend under extremely severe operating condition. Therefore highly improved wear properties of machine elements operating in such circumstances is heavily required. The purpose of this report is to survey current technology for high temperature wear test in order to establish the test plan for the life evaluation of SMART MCP and CEDM bearing materials. Friction and wear test will be done under high pressure (170 MPa) and high temperature (350 degree C) with water as lubricant to simulate the operating condition of the nuclear power reactor. Because pump type for MCP is selected as the caned motor pump which needs no mechanical sealing, the rotating shaft on which bearing is fully submerged by main coolant with high temperature. So MCP bearing operates without additional lubricant. CEDM is adopted as the ball-screw type with fine controllability. So the driving part is designed as the immersed-in type by main coolant. Therefore the anti-wear and reliability of driving parts are much consequent to guarantee the lifetime and the safety of the whole system. Tribometer adapted to high temperature and pressure circumstance is needed to execute bearing material testing. Test parameters are material, sliding speed, sliding distance and applied load. In order to identify the wear mechanism, optical microscope and surface roughness testers are required. The result of this report will provide an elementary data to develop bearing materials and to estimate bearing lifetime for the bearings of MCP and CEDM in SMART. (author)

  10. High-temperature flaw assessment procedure: A state-of-the-art survey

    International Nuclear Information System (INIS)

    High-temperature crack growth under cyclic, static, and combined loading is received with an emphasis on fracture mechanics aspects. Experimental studies of the effects of loading history, microstructure, temperature, and environment on crack growth behavior are described and interpreted. The experimental evidence is used to examine crack growth parameters and theoretical models for fatigue, creep, and creep-fatigue crack propagation at elevated temperatures. The limitations of both elastic and elastic-plastic fracture mechanics for high-temperature subcritical crack growth are assessed. Existing techniques for modeling critical crack growth/ligament instability failure are also presented. Related topics of defect modeling and engineering flaw assessment procedures, nondestructive evaluation methods, and probabilistic failure analysis are briefly discussed. 142 refs., 33 figs

  11. Characterization of Alkali Metal Dispensers and Non-Evaporable Getter Pumps in Ultra-High Vacuum Systems for Cold Atomic Sensors

    OpenAIRE

    Scherer, David R.; Fenner, David B.; Hensley, Joel M.

    2012-01-01

    A glass ultrahigh vacuum chamber with rubidium alkali metal dispensers and non-evaporable getter pumps has been developed and used to create a cold atomic sample in a chamber that operates with only passive vacuum pumps. The ion-mass spectrum of evaporated gases from the alkali metal dispenser has been recorded as a function of dispenser current. The efficacy of the non-evaporable getter pumps in promoting and maintaining vacuum has been characterized by observation of the Rb vapor optical ab...

  12. Interlochen: Exemplary Education in the Arts.

    Science.gov (United States)

    Stathakis, Cathy A.; Pellegrino, Ann S.

    1991-01-01

    The arts and college preparatory academic program at the Interlochen Arts Academy (Michigan) for talented high school students is described. The academy offers intense training in creative writing, dance, music, theater, and visual arts. Also briefly described is the Interlochen Arts Camp which offers intense study in a performing or visual art.…

  13. Teaching Conversations, Contemporary Art, and Figure Drawing

    Science.gov (United States)

    Graham, Mark A.

    2012-01-01

    An important problem for high school art teachers is deciding what belongs in the art curriculum. What works of art, media, or ideas will inspire their students to more fully develop their own artistic potential and critically engage with contemporary art and culture? What artifacts of art, visual culture, or material culture should be included…

  14. Art Markets

    NARCIS (Netherlands)

    P.A. Arora (Payal); F.R.R. Vermeylen (Filip)

    2013-01-01

    textabstractThe advent of digitization has had a profound impact on the art market and its institutions. In this chapter, we focus on the market for visual arts as it finds its expression in (among other) paintings, prints, drawings, photographs, sculpture and the like. These artistic disciplines cl

  15. Vacuum switchgear for fusion experiments

    International Nuclear Information System (INIS)

    A frequently encountered switch application is the interruption of a high level, pulsed, dc current followed by a fast rising recovery voltage. A 7 in. vacuum interrupter with an axial magnetic field has proven to be an effective switch for currents up to 25 kA. Beyond 25 kA, a parallel configuration becomes necessary. The influence of the axial magnetic field on the behavior of parallel vacuum interrupters and test results up to 50 kA are discussed. Also, test results on experimental devices with novel electrode geometries such as the rod-array vacuum interrupter and the Amsler contact interrupter are presented. Interrupters which can carry large dc currents on a continuous basis are frequently required in fusion applications. This requirement occurs in superconducting coil protection circuits and generally involves recovery voltages of 5 kV or less. A specially designed vacuum interrupter with water cooled electrodes has been used to extend the continuous current rating of a commercial interrupter from 1200 A to 13 kA. Two second generation devices with special electrode materials are currently being developed for use with a special actuator and are intended to extend the continuous rating to 25 kA

  16. Extended characterization of a vacuum gas oil by offline LC-high-temperature comprehensive two-dimensional gas chromatography.

    Science.gov (United States)

    Dutriez, Thomas; Courtiade, Marion; Thiébaut, Didier; Dulot, Hugues; Bertoncini, Fabrice; Hennion, Marie-Claire

    2010-06-01

    In a context of environmental preservation, purification and conversion of heavy petroleum cuts into high-quality fuel becomes essential. The interest for the characterization of those very complex matrices becomes a trendy analytical challenge, when it comes to get molecular information for the optimization of industrial processes. Among new analytical techniques, high-temperature 2-D GC has recently proved its applicability to heavy petroleum matrices, but lacks in selectivity to separate all chemical groups. To gain resolution, heart cutting is demonstrated for LC separation of saturated, aromatic and polar compounds prior to high-temperature 2-D GC. Therefore, an extended global resolution was obtained, especially by a better distinction of saturated compounds. This includes iso-paraffins and biomarker polynaphthenic structures, which are impossible to quantify with MS methods. This new way to analyze heavy petroleum fractions gives innovative opportunities for the construction of global weight distributions by carbon atoms number and by chemical families. This can right now be employed for quantitative analysis of heavy petroleum fractions and for studying conversion processes. PMID:20506240

  17. Adsorption geometry, conformation, and electronic structure of 2H-octaethylporphyrin on Ag(111) and Fe metalation in ultra high vacuum

    Science.gov (United States)

    Borghetti, Patrizia; Santo, Giovanni Di; Castellarin-Cudia, Carla; Fanetti, Mattia; Sangaletti, Luigi; Magnano, Elena; Bondino, Federica; Goldoni, Andrea

    2013-04-01

    Due to the growing interest in the ferromagnetic properties of Fe-octaethylporphyrins (Fe-OEP) for applications in spintronics, methods to produce stable Fe-porphyrins with no Cl atoms are highly demanded. Here, we demonstrate the formation of Fe-OEP layers on Ag(111) single crystal by the ultra high vacuum in situ metalation of the free-base 2H-2,3,7,8,12,13,17,18-octaethylporphyrin (2H-OEP) molecules. The metalation proceeds exactly as in the case of 2H-5,10,15,20-tetraphenylporphyrin (2H-TPP) on the same substrate. An extensive surface characterization by means of X-ray photoemission spectroscopy, valence band photoemission, and NEXAFS with synchrotron radiation light provides information on molecular conformation and electronic structure in the monolayer and multilayer cases. We demonstrate that the presence of the ethyl groups affects the tilt of the adsorbed molecules, the conformation of the macrocycle, and the polarization screening in multilayers, but has only a minor effect in the metalation process with respect to 2H-TPP.

  18. 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.

  19. Preparation of Au, U films and Au/U/Au multilayer film by ultra-high vacuum pulsed-laser deposition

    International Nuclear Information System (INIS)

    Metallic uranium has the characteristic of high efficiency of laser to X-ray energy conversion The ultra-high vacuum pulsed-laser deposition (PLD) system was used to prepare Au film, U film and Au/U/Au multilayer film on single Si(100) substrate to prevent the oxidation of uranium. The SEM pictures show that there are spherical metal droplets with diameters less than several microns on the Au and U film surface prepared by PLD under present technology. The surface roughness Ra of less droplet region is less than 1 nm, and the big droplet containing region is less than 15 nm. The amount of droplet on U film surface is much more than Au film surface under the same -deposition condition. The Au/U/Au multilayer film with thickness about 195 nm and Rq between 0.3-1.5 nm was prepared after PLD technology optimization. AES depth profile results reveal that the oxygen content in Au/U/Au multilayer film is less than 5% (atomic percentage), and uranium remains in metal chemical state. It may be effective to reduce the number and size of droplets by reducing the laser power, increasing the distance of target from the substrate and appropriately rising the substrate temperature. (authors)

  20. Cryogenic tritium-hydrogen-deuterium and deuterium-tritium layer implosions with high density carbon ablators in near-vacuum hohlraums

    International Nuclear Information System (INIS)

    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 × 1015 neutrons, 40% of the 1D simulated yield